JP4376599B2 - Active drive type display device - Google Patents

Description

  The present invention relates to a reference current generating circuit of an active drive type display device that drives an electro-optic element at a constant current.

  In recent years, display devices using organic EL elements have been researched and developed as self-luminous elements. Among these, active drive organic EL display devices have advantages such as higher brightness, lower power consumption, and larger screens, and therefore are actively developed.

  For example, in EURODISPLAY2002 16-1 (Non-Patent Document 1): “A Poly-Si TFT 6-bit Current Data Driver for Active Matrix Organic Light Emitting Diode Displays” A circuit configuration of an accurate current-driven data driver (signal electrode driving circuit) has been proposed.

  The circuit configuration of the announced current-driven data driver will be briefly described below with reference to FIGS. 13, 14, and 15. FIG.

  FIG. 13 shows a data driver circuit for driving a display panel in which a current driving circuit is arranged for each pixel and a gate driver circuit (scanning electrode driving circuit) in order to drive the organic EL element with constant current. In particular, the circuit configuration of the data driver circuit is shown in more detail.

  Reference numeral 200 denotes a display panel having 120 dots × RGB in the horizontal direction and 136 dots in the vertical direction, in which a current driving circuit is arranged for each pixel. Reference numeral 201 is a 60-bit shift register. Reference numeral 202 is a 6-bit data register. Reference numeral 203 is a 6-bit line latch, and reference numeral 204 is a 60-bit shift register different from the shift register 201. Reference numeral 205 is a digital-to-current converter unit (hereinafter simply referred to as DCC) that converts a 6-bit digital signal into a current signal. Reference numeral 206 is a 6-bit standard current signal generating circuit, and reference numeral 207 is a 1 to 2 selector. Reference numeral 208 is a gate driver.

  The shift register 201 sequentially shifts the data shift signal and outputs the signal to the data register 202. The data register 202 stores RGB 6-bit digital image signals in the register in accordance with the input signal.

  Here, for convenience of explanation, a circuit for processing the red image signal is shown, and a circuit for processing the green and blue image signals is omitted. The stored 6-bit digital image signal is output to the line latch 203, and the 6-bit digital image signal is latched by the line latch 203 in accordance with the latch signal. The latched 6-bit digital image signal is output to the DCC 205.

  The shift register 204 sequentially shifts the memorize signal and outputs the signal to the DCC 205. The reference current signal generation circuit 206 has six types of reference current signals Is, Is × 2, Is × 4, Is × 8, Is × 16, which serve as a reference for generating 64 types (6 bits) of current signals in the DCC 205. A circuit that generates Is × 32 outputs these six types of reference current signals to the DCC 205.

  The DCC 205 converts the 6-bit digital image signal output from the line latch 203 into current signals based on the six types of reference current signals output from the reference current signal generation circuit 206 and outputs the current signals to the selector 207. When the digital image signal is not converted into a current signal, the reference current signal output from the reference current signal generation circuit 206 is sampled and held in the DCC circuit 205 in accordance with the signal output from the shift register 204.

  Whether the selector 207 outputs the current signal output from the DCC 205 in response to the selector signal (selection control signal) to outputs 1, 3,..., 127, 129 or outputs 2, 4,. Is selected. The outputs 1 to 120 are connected to data electrodes (not shown) of the display panel (organic EL panel) 200.

  Next, a detailed circuit configuration of the DCC 205 in FIG. 13 will be described below with reference to FIGS. 14 and 15.

  In FIG. 14, the 6-bit line latch, 60-bit shift register 2, 6-bit DCC, 6-bit reference current signal generation circuit, and 1-to-2 selector are the same as those in FIG. Reference numeral 210 is a 6-bit DCC unit, reference numeral 211 is 6-bit DCC (A), reference numeral 212 is 6-bit DCC (B), reference numeral 213 is a selector for selecting A or B, and reference numeral 214 is 1-bit DCC.

  FIG. 15 shows a 1-bit DCC 214. In the figure, reference numerals 220, 221, 222, and 223 are N-channel TFTs, and reference numeral 224 is a capacitor.

  The drain of the N-channel TFT 220 is connected to the input current signal Iin, the gate is connected to the control signal MS together with the gate of the N-channel TFT 221, and the source is connected to the drain of the N-channel TFT 221, the drain of the N-channel TFT 222, and the source of the N-channel TFT 223. It is connected. The source of the N-channel TFT 221 is connected to the gate of the N-channel TFT 222 and the capacitor 224, the source of the N-channel TFT 222 is connected to GND, the gate of the N-channel TFT 223 is connected to Data, and the drain outputs a current signal. Connected to a terminal Iout.

  Here, the operation of the 1-bit DCC 214 in FIG. 15 will be briefly described. By setting the MS signal to “H” (high level) and the Data signal to “L” (low level), the N-channel TFTs 220 and 221 are turned on and the N-channel TFT 223 is turned off. At this time, when the reference current signal Is is input to Iin which is the drain terminal of the N-channel TFT 220, a voltage necessary for the TFT 222 to flow this Is is generated at the gate of the N-channel TFT 222 (sample operation). Further, this voltage is held in the capacitor 224 (hold operation).

  Thereafter, the N-channel TFTs 220 and 221 are turned off by setting the MS signal to “L”. Then, the Data signal is changed from “L” to “H” according to the image Data input to the 6-bit data register 202 in FIG. 13, or the “L” state is maintained. When Data is “H”, the N-channel TFT 223 is turned on, and the current of the reference current signal Is is sucked from Iout which is the drain terminal of the N-channel TFT 223. On the other hand, when Data is “L”, the N-channel TFT 223 is turned off and no current is sucked from the drain terminal Iout of the N-channel TFT 223.

  The 1-bit DCC 214 that performs such an operation includes six same circuits in the 6-bit DCC (A) 211 in FIG. The 6-bit DCC unit 210 includes a 6-bit DCC (B) 212 having the same circuit configuration as that of the 6-bit DCC (A) 211.

  That is, in the DCC 205, the reference currents Is, Is × 2, Is × 4, Is × 8, which are output from the 6-bit reference current generation circuit to the 6-bit DCC (A) 211 in accordance with the signal output from the shift register 204, Whether six types of reference current signals of Is × 16 and Is × 32 are sampled and held, or whether six types of reference current signals are sampled and held in the 6-bit DCC (B) 212 is determined. Further, the reference current signal is sampled and held in order in 60 circuits in the DCC 205.

  Next, each output control TFT in the 6-bit DCC (A) 211 is turned on or off according to the data of the 6-bit line latch 203, so that a current corresponding to the 6-bit image data passes through the selector 213 and the selector 207. Current is sucked in from output 1 or 2.

  On the other hand, when the 6-bit-DCC (A) 211 is performing an output operation, the 6-bit-DCC (B) 212 samples and holds six types of reference current signals by signals output from the shift register 204. In addition, 60 DCC circuits (B) in the DCC 205 are sequentially sampled and held. When this is completed, this time, each output control TFT in the 6-bit DCC (B) 212 is turned on or off according to the data of the line latch 203, so that the current corresponding to the 6-bit data passes through the selector 213 and the selector 207. Current is sucked in from output 1 or 2. When this operation is performed, the 6-bit DCC (A) 211 performs a sample and hold operation of the reference current signal. In this manner, the current driver shown in FIG. 13 converts the current signal into a 6-bit digital image signal, and transmits the signal to output connected to the display panel 200.

  Here, for convenience of explanation, since 64 kinds of sink current values are determined according to 6-bit data, 6 of Is, Is × 2, Is × 4, Is × 8, Is × 16, and Is × 32 are used as reference current signals. Although the type is input, the circuit configuration for generating the reference current signal is not particularly mentioned.

  Incidentally, as a reference current signal generation circuit of a semiconductor integrated circuit using single crystal Si, there is a circuit configuration proposed in Japanese Patent Laid-Open No. 2000-293245 (Patent Document 1). FIG. 16 shows a circuit configuration example.

  In FIG. 16, reference numeral 300 is a constant voltage circuit, which outputs a constant voltage. Reference numeral 301 denotes an operational amplifier such as an operational amplifier. A signal voltage is applied to the gate of the control N-channel transistor 302 so that the voltages generated in the reference resistor 303 are equal with respect to the output voltage from the constant voltage circuit 300. give.

  The reference resistor 303 is connected to the source side of the control N-channel transistor 302 via the reference voltage input terminal VREF. The drain of the P-channel transistor 304 is connected to the drain side of the control N-channel transistor 302.

  The control N-channel transistor 302 of the minimum reference current signal generation circuit 309 passes the minimum reference current signal Is, which is a constant current, based on the output voltage from the constant voltage circuit 300 and the reference resistor 303.

  In the current mirror circuit 310, the P channel transistors 304 and 305, 304 and 306, and 304 and 307 constitute current mirrors, respectively. Therefore, in the reference current generation circuit of FIG. 16, currents Is-1, Is-2, and Is-3 flowing between the source and drain of the P-channel transistors 305, 306, and 307 are generated in the minimum reference current signal generation circuit 309. And operate so as to be equal to the minimum reference current signal Is.

  FIG. 17 does not output the same current by changing the connection of the P-channel transistors in the current mirror circuit 310 as in FIG. 16, but instead of 1 ×, 2 ×, 4 ×, 8 ×, 16 ×, and 32 ×. The circuit which outputs each electric current is shown.

As shown in FIG. 17, in the current mirror circuit 320, the P-channel transistor 304 forms a current mirror with each of the P-channel transistors 321 to 383. The P channel transistor 321 outputs the same current as the minimum reference current signal Is generated by the minimum reference current signal generation circuit 309, and the P channel transistors 322 and 323 to which the drains are connected have a current twice as large as the minimum reference current signal Is. The P channel transistors 324, 325, 326, and 327 to which Is × 2 is output and the drain is connected output a current Is × 4 that is four times the minimum reference current signal Is, and the P channel to which the drain is connected The transistors 328 to 335 output a current Is × 8 that is eight times the minimum reference current signal Is, and the P-channel transistors 336 to 351 connected to the drain output a current Is × 16 that is 16 times the minimum reference current signal Is. The P-channel transistors 352 to 383 to which the drains are connected have a minimum reference current. No. outputs a 32-fold current Is × 32 of Is. The reference current signal output in this way is connected to, for example, the 6-bit DCC unit 205 in FIG.

JP 2000-293245 (release date: October 20, 2000) 16-1 of EURODISPLAY2002, “A Poly-Si TFT 6-bit Current Data Driver for Active Matrix Organic Light Emitting Diode Displays”, p279-p282, by K. Abe et al, published 2002

  However, the above conventional technique has the following problems. That is, in the configuration shown in FIGS. 16 and 17, the reference current generating circuit is formed using a single crystal Si substrate, but when formed on a glass substrate, the reference current generating circuit is formed using a polycrystalline Si (polysilicon) thin film. 16 and the reference current generating circuit shown in FIG. 17 are formed.

  It is known that a thin film transistor (TFT) formed using a polycrystalline Si thin film has a large difference in TFT characteristics such as threshold voltage and electron mobility between TFTs formed on the same glass substrate. That is, when the circuits shown in FIGS. 16 and 17 are configured with TFTs, the current flowing in the input-side transistor and the current flowing in the output side can be obtained only when the characteristics of the transistors constituting the current mirror circuit are the same. However, in the configuration of FIG. 16, there are cases where the currents output from the three locations with respect to the minimum reference current signal Is are not the same as Is.

  In the configuration of FIG. 17, an accurate double current signal is not output with respect to the minimum reference current signal Is, and an accurate multiple current signal is obtained in the same manner as 4 times, 8 times, 16 times, and 32 times. It may not be possible.

  When such a reference current signal is input to the circuit shown in FIG. 13, an accurate current value corresponding to the image data cannot be obtained. Therefore, the pixel portion in a display device such as an organic EL display device is not desired. The desired brightness may not be obtained, and a desired image cannot be obtained.

  The present invention has been made in view of the above problems, and an object of the present invention is to accurately generate a plurality of double current reference current signals determined by a multiple of the minimum reference current signal, and to input image data. An object of the present invention is to provide an active drive type display device that can always display a desired image.

  In order to solve the above problems, the active drive type display device of the present invention is based on n kinds of reference current signals output from a reference current generating circuit, which are digital image signals of n (n: natural number of 2 or more) bits. In an active drive type display device that includes a digital signal-current signal conversion circuit for converting into a current signal and displays the electro-optic elements in gradation based on the converted current signal via a signal electrode drive circuit, It is characterized by taking measures.

  That is, the active drive type display device includes a minimum reference current signal generation circuit that generates a minimum reference current signal, and a plurality of the reference signals that are connected to output the n types of reference current signals by duplicating the minimum reference current signal. Current discharge type current duplication circuit, and the minimum reference current signal from the current discharge type current duplication circuit so that the minimum reference current signal does not flow from two or more current discharge type current duplication circuits at the same time. Each of the reference current signal generation circuits is duplicated by flowing it, and the minimum reference current signal duplicated from the current discharge type current duplication circuit is output to obtain the n kinds of reference current signals.

  The current discharge type current duplicating circuit preferably includes a sample and hold unit that samples and holds the minimum reference current signal, and an output unit that discharges the sampled and held minimum reference current signal.

  The sample and hold unit includes first and third TFTs of P or N channel, respectively. The first, second, and third TFTs sample the minimum reference current signal, and the third TFT samples the minimum reference current. It is preferable that the signal is held through a capacitor, and the output unit is composed of third and fourth TFTs of P or N channel and discharges the sampled and held minimum reference current signal.

  In order to solve the above problem, another active drive type display device of the present invention converts n (n: a natural number of 2 or more) bits of digital image signals into n types of reference current signals output from the reference current generation circuit. In an active drive type display device comprising a digital signal-current signal conversion circuit for converting into a current signal based on the signal electrode drive circuit and displaying the electro-optic elements in gradation based on the converted current signal via a signal electrode drive circuit, It is characterized by the following measures.

  That is, the active drive type display device includes a minimum reference current signal generation circuit that generates a minimum reference current signal, and a plurality of currents that are connected to duplicate the minimum reference current signal and suck the n types of reference current signals. A current sink type current replication circuit, and the current sink type current reference circuit receives the minimum reference current signal from the minimum reference current signal generation circuit so that two or more current current sink type current replication circuits do not suck the minimum reference current signal at the same time. Each of the current duplicating circuits is duplicated by flowing into each of the current replicating circuits, and the minimum reference current signal replicated in the current sink type current replicating circuit is sucked to obtain the n kinds of reference current signals.

  The current sink type current duplicating circuit preferably includes a sample and hold unit that samples and holds the minimum reference current signal and an output unit that sucks the sampled and held minimum reference current signal.

  The sample and hold unit includes first and third TFTs of P or N channel, respectively. The first, second, and third TFTs sample the minimum reference current signal, and the third TFT samples the minimum reference current. It is preferable that the signal is held through a capacitor, and the output unit is composed of third and fourth TFTs of P or N channel, and sucks the sampled and held minimum reference current signal.

  In order to solve the above-described problem, another active drive type display device of the present invention provides n types of reference current signals output from a reference current generation circuit as digital image signals of n (n: natural number of 2 or more) bits. In an active drive display device that includes a digital signal-current signal conversion circuit that converts a current signal based on the signal, and that performs gradation display on each electro-optic element based on the converted current signal via a signal electrode drive circuit The following measures have been taken.

  That is, the active drive type display device is connected to a minimum reference current signal generating circuit for generating a minimum reference current signal and to output the n kinds of reference current signals, respectively, and a current that duplicates the minimum reference current signal Two first current replication circuits composed of discharge type current replication circuits, and a plurality of second current replication circuits composed of a pair of current suction type current replication circuits and a current ejection type current replication circuit connected in series The output terminal of the first current replication circuit and the input terminal of the second current replication circuit are connected to each other, and the second current replication circuit other than for outputting the n kinds of reference current signals is connected to the output terminal. The minimum reference current signal is supplied from the first current replication circuit so that the minimum reference current signal does not flow from two first current replication circuits at the same time. With flow respectively into the flow signal generating circuit is characterized in that output the reference current signal of the n type second current duplication circuit for the output.

  The current discharge type current replication circuit of the first current replication circuit is configured to sample and hold the minimum reference current signal, and to discharge the sampled and held minimum reference current signal to the output terminal. Each of the second current duplicating circuits includes a second sample and hold unit that samples and holds a current signal flowing through the input terminal, and the second current duplicating circuit includes: The current discharge type current duplicating circuit of the duplicating circuit includes a third sample-and-hold unit that samples and holds the current signal held by the second sample-and-hold unit, and the output terminal that receives the sample-held current signal. And a third output unit that discharges to the outlet.

  The first sample and hold unit includes first and third TFTs of P or N channel, respectively. The first, second, and third TFTs sample the minimum reference current signal, and the third TFT samples the minimum sampled. A reference current signal is held through a first capacitor, and the first output unit includes third and fourth TFTs of P or N channel, and discharges the sampled and held minimum reference current signal, and the second sample. The hold unit is composed of P or N channel fifth to seventh TFTs, the fifth, sixth and seventh TFTs sample the current signal flowing to the input terminal, and the seventh TFT captures the sampled current signal. The third sample-and-hold unit is composed of P- or N-channel eighth to tenth TFTs, respectively, through a second capacitor. The eighth, ninth, and tenth TFTs sample the current signal held through the second capacitor, the tenth TFT holds the sampled current signal through the third capacitor, and the third output unit. Is preferably composed of P and N channel tenth and eleventh TFTs, and discharges the sampled and held current signal to the output terminal.

  In order to solve the above-described problem, another active drive type display device of the present invention provides n types of reference current signals output from a reference current generation circuit as digital image signals of n (n: natural number of 2 or more) bits. In an active drive display device that includes a digital signal-current signal conversion circuit that converts a current signal based on the signal, and that performs gradation display on each electro-optic element based on the converted current signal via a signal electrode drive circuit The following measures have been taken.

  That is, the active drive type display device is connected to a minimum reference current signal generating circuit for generating a minimum reference current signal and to output the n kinds of reference current signals, respectively, and a current that duplicates the minimum reference current signal Two first current replication circuits composed of suction type current replication circuits, and a plurality of second current replication circuits composed of a pair of current discharge type current replication circuits and a current suction type current replication circuit connected in series The output terminal of the first current replication circuit and the input terminal of the second current replication circuit are connected to each other, and the second current replication circuit other than for outputting the n kinds of reference current signals is connected to the output terminal and the input terminal. The minimum reference current signal is supplied from the minimum reference current signal generation circuit to prevent the minimum reference current signal from flowing to two first current replication circuits at the same time. With flow respectively to the current duplication circuit, a second current duplication circuit for the output it is characterized by sucking the n kinds of reference current signals, respectively.

  The current sink type current replication circuit of the first current replication circuit includes a first sample and hold unit that samples and holds the minimum reference current signal, and a first sample and hold unit that samples and holds the minimum reference current signal into the output terminal. Each of the second current duplicating circuits includes a second sample and hold unit that samples and holds a current signal flowing through an input terminal, and the second current duplicating circuit includes: The current sink type current replication circuit of the circuit samples and holds a current signal held by the second sample and hold unit, and sucks the sampled and held current signal from the output terminal. The structure provided with the 3rd output part may be sufficient.

  The first sample and hold unit includes first and third TFTs of P or N channel, respectively. The first, second, and third TFTs sample the minimum reference current signal, and the third TFT samples the minimum sampled. A reference current signal is held through a first capacitor, and the first output unit includes third and fourth TFTs of P or N channel, and sucks in the sampled and held minimum reference current signal, and The hold unit is composed of P or N channel fifth to seventh TFTs. The fifth, sixth, and seventh TFTs sample current signals flowing through the input terminals, and the seventh TFT receives the sampled current signals. The third sample and hold unit is composed of P or N channel 8th to 10th TFTs, respectively. The eighth, ninth, and tenth TFTs sample the current signal held through the second capacitor, the tenth TFT holds the sampled current signal through the third capacitor, and the third output unit. Is preferably composed of 10th and 11th TFTs of P or N channel, and sucks the sampled and held current signal from the output terminal.

  In order to solve the above-described problem, another active drive type display device of the present invention provides n types of reference current signals output from a reference current generation circuit as digital image signals of n (n: natural number of 2 or more) bits. In an active drive display device that includes a digital signal-current signal conversion circuit that converts a current signal based on the signal, and that performs gradation display on each electro-optic element based on the converted current signal via a signal electrode drive circuit The following measures have been taken.

  That is, the active drive type display device is connected to a minimum reference current signal generating circuit for generating a minimum reference current signal and to output the n kinds of reference current signals, respectively, and a current that duplicates the minimum reference current signal Two first current replication circuits composed of discharge type current replication circuits, and a plurality of second current replication circuits composed of a pair of current suction type current replication circuits and a current ejection type current replication circuit connected in series And the output terminal of the first current replication circuit and the input terminal of the second current replication circuit are connected to each other, and the second current replication circuit is connected to the output terminal and the input terminal, respectively. When the minimum reference current signal is sent from the first current replication circuit to the minimum reference current signal generation circuit so that the minimum reference current signal does not flow from the one current replication circuit, Is characterized in that outputs a reference current signal of the n type from said first and second current replication circuit.

  The current discharge type current replication circuit of the first current replication circuit is configured to sample and hold the minimum reference current signal, and to discharge the sampled and held minimum reference current signal to the output terminal. Each of the second current duplicating circuits includes a second sample and hold unit that samples and holds a current signal flowing through the input terminal, and the second current duplicating circuit includes: The current discharge type current duplicating circuit of the duplicating circuit includes a third sample-and-hold unit that samples and holds the current signal held by the second sample-and-hold unit, and the output terminal that receives the sample-held current signal. The structure provided with the 3rd output part discharged to is preferable.

  The first sample and hold unit includes first and third TFTs of P or N channel, respectively. The first, second, and third TFTs sample the minimum reference current signal, and the third TFT samples the minimum sampled. A reference current signal is held through a first capacitor, and the first output unit includes third and fourth TFTs of P or N channel, and discharges the sampled and held minimum reference current signal, and the second sample. The hold unit is composed of P or N channel fifth to seventh TFTs, the fifth, sixth and seventh TFTs sample the current signal flowing to the input terminal, and the seventh TFT captures the sampled current signal. The third sample-and-hold unit is composed of P- or N-channel eighth to tenth TFTs, respectively, through a second capacitor. The eighth, ninth, and tenth TFTs sample the current signal held through the second capacitor, the tenth TFT holds the sampled current signal through the third capacitor, and the third output unit. Is preferably composed of P and N channel tenth and eleventh TFTs, and discharges the sampled and held current signal to the output terminal.

  In order to solve the above-described problem, another active drive type display device of the present invention provides n types of reference current signals output from a reference current generation circuit as digital image signals of n (n: natural number of 2 or more) bits. In an active drive display device that includes a digital signal-current signal conversion circuit that converts a current signal based on the signal, and that performs gradation display on each electro-optic element based on the converted current signal via a signal electrode drive circuit The following measures have been taken.

  That is, the active drive type display device is connected to a minimum reference current signal generating circuit for generating a minimum reference current signal and to output the n kinds of reference current signals, respectively, and a current that duplicates the minimum reference current signal Two first current replication circuits composed of suction type current replication circuits, and a plurality of second current replication circuits composed of a pair of current discharge type current replication circuits and a current suction type current replication circuit connected in series The output terminal of the first current replication circuit and the input terminal of the second current replication circuit are connected to each other, and the second current replication circuit has an output terminal and an input terminal connected to each other. The minimum reference current signal is supplied from the minimum reference current signal generation circuit to the first current replication circuit so that the minimum reference current signal does not flow to the current replication circuit. It said first and second current replication circuit is characterized by sucking respective reference current signal of the n type.

  The current sink type current replication circuit of the first current replication circuit includes a first sample and hold unit that samples and holds the minimum reference current signal, and a first sample and hold unit that samples and holds the minimum reference current signal into the output terminal. Each of the second current duplicating circuits includes a second sample and hold unit that samples and holds a current signal flowing through an input terminal, and the second current duplicating circuit includes: The current sink type current duplicating circuit of the circuit includes a third sample and hold unit that samples and holds the current signal held by the second sample and hold unit, and the sample and hold current signal from the output terminal. The structure provided with the 3rd output part which inhales is preferable.

  The first sample and hold unit includes first and third TFTs of P or N channel, respectively. The first, second, and third TFTs sample the minimum reference current signal, and the third TFT samples the minimum sampled. A reference current signal is held through a first capacitor, and the first output unit includes third and fourth TFTs of P or N channel, and sucks in the sampled and held minimum reference current signal, and The hold unit is composed of P or N channel fifth to seventh TFTs. The fifth, sixth, and seventh TFTs sample current signals flowing through the input terminals, and the seventh TFT receives the sampled current signals. The third sample and hold unit is composed of P or N channel 8th to 10th TFTs, respectively. The eighth, ninth, and tenth TFTs sample the current signal held through the second capacitor, the tenth TFT holds the sampled current signal through the third capacitor, and the third output unit. Is preferably composed of 10th and 11th TFTs of P or N channel, and sucks the sampled and held current signal from the output terminal.

  In order to solve the above-described problem, another active drive type display device according to the present invention includes scanning electrodes arranged in rows and signal electrodes arranged in columns, and pixels where these scanning electrodes and signal electrodes intersect. An electro-optic element, a plurality of thin film transistors, and a capacitor are disposed in the region, and includes a scan electrode drive circuit that drives the scan electrode, a signal electrode drive circuit that drives the signal electrode, and a reference current generation circuit, and is provided in the pixel region In an active drive type display device for writing a desired current signal in a current duplicating circuit and controlling gradation of current flowing to the electro-optic element, a current discharge type current duplicating circuit for duplicating a current signal as a minimum reference is provided. Current discharge capable of generating multiple reference current signals by connecting a plurality of current discharge type current duplicating circuits in parallel as a minimum unit to generate a desired reference current signal Comprising a mold reference current generating circuit, the plurality of reference current signals digital signals of the signal electrode driving circuit - is characterized by connecting to a current signal conversion circuit.

  In order to solve the above-described problem, another active drive type display device according to the present invention includes scanning electrodes arranged in rows and signal electrodes arranged in columns, and pixels where these scanning electrodes and signal electrodes intersect. An electro-optic element, a plurality of thin film transistors, and a capacitor are disposed in the region, and includes a scan electrode drive circuit that drives the scan electrode, a signal electrode drive circuit that drives the signal electrode, and a reference current generation circuit, and is provided in the pixel region Write a desired current signal to the current replication circuit, and control the current flowing to the electro-optic element, and in an active drive display device that displays gradation, minimize the current sink type current replication circuit that replicates the minimum reference current signal. A current sink capable of generating a plurality of reference current signals by generating a desired reference current signal by connecting a plurality of current sink type current duplicating circuits in parallel as a unit Comprising a mold reference current generating circuit, the plurality of reference current signals digital signals of the signal electrode driving circuit - is characterized by connecting to a current signal conversion circuit.

  In order to solve the above-described problem, another active drive type display device according to the present invention includes scanning electrodes arranged in rows and signal electrodes arranged in columns, and pixels where these scanning electrodes and signal electrodes intersect. An electro-optic element, a plurality of thin film transistors, and a capacitor are disposed in the region, and includes a scan electrode drive circuit that drives the scan electrode, a signal electrode drive circuit that drives the signal electrode, and a reference current generation circuit, and is provided in the pixel region A plurality of current discharge type current duplications for duplicating a minimum reference current signal in an active drive type display device for writing a desired current signal in a current duplication circuit and controlling gradation of the current flowing to the electro-optic element. The current, which is the minimum standard, is composed of a plurality of current discharge type current duplication circuits that are configured in pairs with a current sink type current duplication circuit and a current discharge type current duplication circuit. It has a reference current generation circuit configured by a current discharge type current duplicating circuit for generating a current signal that is double the signal and holding each generated current signal, and the reference current signal is a signal electrode drive circuit. The digital signal-current signal conversion circuit is connected.

  In order to solve the above-described problem, another active drive type display device according to the present invention includes scanning electrodes arranged in rows and signal electrodes arranged in columns, and pixels where these scanning electrodes and signal electrodes intersect. An electro-optic element, a plurality of thin film transistors, and a capacitor are disposed in the region, and includes a scan electrode drive circuit that drives the scan electrode, a signal electrode drive circuit that drives the signal electrode, and a reference current generation circuit, and is provided in the pixel region A plurality of current suction type current duplicating circuits for duplicating a current signal serving as a minimum reference in an active drive type display device in which a desired current signal is written in a current duplicating circuit and gray scale is displayed by controlling a current flowing to the electro-optic element In addition, a current discharge type current duplicating circuit and a current sink type current duplicating circuit are paired with a plurality of current sinking type current duplicating circuits to form a minimum reference voltage. A reference current generation circuit configured by a current sink type current duplicating circuit for generating a current signal twice the signal and holding each generated current signal, and the reference current signal of the signal electrode drive circuit It is characterized by being connected to a digital signal-current signal conversion circuit.

  In order to solve the above-described problem, another active drive type display device according to the present invention includes scanning electrodes arranged in rows and signal electrodes arranged in columns, and pixels where these scanning electrodes and signal electrodes intersect. An electro-optic element, a plurality of thin film transistors, and a capacitor are disposed in the region, and includes a scan electrode drive circuit that drives the scan electrode, a signal electrode drive circuit that drives the signal electrode, and a reference current generation circuit, and is provided in the pixel region A plurality of current discharge type current duplications for duplicating a minimum reference current signal in an active drive type display device for writing a desired current signal in a current duplication circuit and controlling gradation of the current flowing to the electro-optic element. The current, which is the minimum standard, is composed of a plurality of current discharge type current duplication circuits that are configured in pairs with a current sink type current duplication circuit and a current discharge type current duplication circuit. Duplicate the multiplied times the current of the signal, connect all the outputs of the current discharge type current replication circuit, the output of the digital signal of the signal electrode driving circuit - is characterized by connecting to a current signal conversion circuit.

  In order to solve the above-described problem, another active drive type display device according to the present invention includes scanning electrodes arranged in rows and signal electrodes arranged in columns, and pixels where these scanning electrodes and signal electrodes intersect. An electro-optic element, a plurality of thin film transistors, and a capacitor are disposed in the region, and includes a scan electrode drive circuit that drives the scan electrode, a signal electrode drive circuit that drives the signal electrode, and a reference current generation circuit, and is provided in the pixel region A plurality of current suction type current duplicating circuits for duplicating a current signal serving as a minimum reference in an active drive type display device in which a desired current signal is written in a current duplicating circuit and gray scale is displayed by controlling a current flowing to the electro-optic element In addition, a current discharge type current duplicating circuit and a current sink type current duplicating circuit are paired with a plurality of current sinking type current duplicating circuits to form a minimum reference voltage. Duplicate the multiplied times the current of the signal, connect all the outputs of the current sink-type current replication circuit, the output of the digital signal of the signal electrode driving circuit - is characterized by connecting to a current signal conversion circuit.

  The electro-optical element is preferably an organic EL element.

  As described above, the active drive display device according to the present invention duplicates the minimum reference current signal generation circuit that generates the minimum reference current signal, and outputs the n types of reference current signals. A plurality of current discharge type current duplicating circuits connected in such a manner that the minimum current reference signal does not flow from two or more current discharge type current duplication circuits at the same time. The minimum reference current signal is passed through the minimum reference current signal generation circuit and replicated, and the minimum reference current signal replicated from the current discharge type current replication circuit is output to obtain the n types of reference current signals. It is characterized by that.

  According to the above invention, the n-bit digital image signal is converted into the current signal by the digital signal-current signal conversion circuit based on the n kinds of reference current signals output from the reference current generation circuit, and the signal electrode driving is performed. Through the circuit, the electro-optic elements are displayed in gradation based on the current signal thus converted.

  The plurality of current discharge type current duplicating circuits are connected so that the n kinds of reference current signals are output from the reference current generating circuit, and each duplicating circuit duplicates and duplicates the minimum reference current signal. Output the minimum reference current signal. Since each duplication circuit is connected as described above, the duplicated minimum reference current signal is output from each current discharge type current duplication circuit, so that the above-mentioned n types of reference current signals can be obtained as a whole. become.

  During the duplication, a minimum reference current signal is sent from the current discharge type current duplication circuit to the minimum reference current signal generation circuit. At this time, since the minimum reference current signal does not flow from two or more current discharge type current duplication circuits at the same time, the same minimum reference current signal always flows from the current discharge type current duplication circuit to the minimum reference current signal generation circuit. Thus, the same minimum reference current signal can be duplicated with high accuracy in each duplication circuit.

  Unlike the prior art in which an accurate reference current signal cannot be obtained when there is a large difference in characteristics such as threshold voltage and electron mobility between thin film transistors constituting a current mirror circuit, according to the above invention, the same minimum reference current is always obtained. A signal flows from the current discharge type current replication circuit to the minimum reference current signal generation circuit, and the minimum reference current signal is copied and output from the current discharge type current replication circuit.

  Thereby, it is possible to always generate an accurate reference current signal without being restricted by the characteristic difference between the thin film transistors. Therefore, the electro-optic element always has a desired luminance, and also has an effect that a desired image can be reliably obtained.

  The current discharge type current duplicating circuit preferably includes a sample and hold unit and an output unit that discharges the sampled and held minimum reference current signal.

  The sample and hold unit includes first and third TFTs of P or N channel, respectively. The first, second, and third TFTs sample the minimum reference current signal, and the third TFT samples the minimum reference current. It is preferable that the signal is held through a capacitor, and the output unit is composed of third and fourth TFTs of P or N channel and discharges the sampled and held minimum reference current signal.

  As described above, the current discharge type current duplicating circuit is not configured as a current mirror circuit, so that the above effect can be obtained.

  As described above, the other active drive type display device according to the present invention duplicates the minimum reference current signal and the minimum reference current signal generation circuit that generates the minimum reference current signal, and converts the n types of reference current signals. A plurality of current sink type current duplicating circuits connected so as to suck in, and at least two current sink type current duplicating circuits at the same time from the minimum reference current signal generating circuit so as not to suck in the minimum reference current signal. A reference current signal is duplicated by flowing to each of the current sink type current replication circuits, and the minimum reference current signal replicated to the current sink type current replication circuit is sucked to obtain the n kinds of reference current signals. It is said.

  According to the above invention, an n-bit digital image signal is converted into a current signal based on n types of reference current signals output from the reference current generation circuit by the digital signal-current signal conversion circuit in the signal electrode driving circuit. Based on the converted current signal, the electro-optic elements are displayed in grayscale via the signal electrode drive circuit.

  The plurality of current sink type current duplicating circuits are connected so that the above-mentioned n kinds of reference current signals are sucked, and each duplicating circuit duplicates the minimum reference current signal and sucks the duplicated minimum reference current signal. . Since each duplication circuit is connected as described above, the duplicated minimum reference current signal flows to each current sink type current duplication circuit, so that the n types of reference current signals are obtained as a whole.

  During the duplication, a minimum reference current signal is supplied from the minimum reference current signal generation circuit to the current sink type current duplication circuit. At this time, since the minimum reference current signal does not flow to two or more current sink type current replication circuits at the same time, the same minimum reference current signal is always sucked from the minimum reference current signal generation circuit to the current sink type current replication circuit. As a result, the same minimum reference current signal can be duplicated with high accuracy in each duplication circuit.

  Unlike the prior art in which an accurate reference current signal cannot be obtained when there is a large difference in characteristics such as threshold voltage and electron mobility between thin film transistors constituting a current mirror circuit, according to the above invention, the same minimum reference current is always obtained. A signal flows from the minimum reference current signal generation circuit to the current sink current replication circuit, and the minimum reference current signal is sucked and replicated in the current sink current replication circuit.

  Thereby, it is possible to always generate an accurate reference current signal without being restricted by the characteristic difference between the thin film transistors. Therefore, the electro-optic element always has a desired luminance, and also has an effect that a desired image can be reliably obtained.

  Preferably, the current sink type current replication circuit includes a sample and hold unit and an output unit that sucks the sampled and held minimum reference current signal.

  The sample and hold unit includes first and third TFTs of P or N channel, respectively. The first, second, and third TFTs sample the minimum reference current signal, and the third TFT samples the minimum reference current. It is preferable that the signal is held through a capacitor, and the output unit is composed of third and fourth TFTs of P or N channel, and sucks the sampled and held minimum reference current signal.

  As described above, the current suction type current duplicating circuit is not configured as a current mirror circuit, and thus the above-described effects can be obtained.

  Still another active drive type display device according to the present invention is connected to the minimum reference current signal generating circuit for generating the minimum reference current signal and to output the n kinds of reference current signals, as described above. It consists of two first current replication circuits composed of current discharge type current replication circuits that replicate the minimum reference current signal, a pair of current suction type current replication circuits and a current discharge type current replication circuit connected in series. A plurality of second current replication circuits, wherein an output terminal of the first current replication circuit and an input terminal of the second current replication circuit are connected to each other, and other than for outputting the n types of reference current signals The second current replication circuit has an output terminal and an input terminal connected to each other, and the minimum reference current signal does not flow from the two first current replication circuits at the same time. A signal with flow respectively to the minimum reference current signal generation circuit, is characterized in that output the reference current signal of the n type second current duplication circuit for the output.

  According to the above invention, an n-bit digital image signal is converted into a current signal based on n types of reference current signals output from the reference current generation circuit by the digital signal-current signal conversion circuit in the signal electrode driving circuit. Based on the converted current signal, the electro-optic elements are displayed in grayscale via the signal electrode drive circuit.

  Two first current duplicating circuits are provided, each of which comprises a current discharge type current duplicating circuit, duplicating the minimum reference current signal and outputting it. The second current replication circuit includes a pair of current suction type current replication circuits and a current discharge type current replication circuit connected in series, and a plurality of second current replication circuits are provided. The first and second current replication circuits are connected to output the n kinds of reference current signals.

  The minimum reference current signal is sent from the first current replication circuit to the minimum reference current signal generation circuit. The minimum reference current signal flows from the first current replication circuit to the minimum reference current signal generation circuit, but at this time, the minimum reference current signal does not flow from the two first current replication circuits at the same time. As a result, since the same minimum reference current signal is always discharged from the first current replication circuit to the minimum reference current signal generation circuit, the same minimum reference current signal is replicated with high accuracy in each first current replication circuit. It becomes possible to do.

  On the other hand, the output terminal of the first current replication circuit and the input terminal of the second current replication circuit are connected to each other. The second current replication circuits are connected to each other at their input terminals. In addition, the second current duplicating circuit other than that for outputting the n types of reference current signals has an output terminal and an input terminal connected to each other.

  Due to this connection relationship, when a duplicate of the same minimum reference current signal is input from one of the two first current replication circuits to one of the second current replication circuits, the same minimum reference current A duplicate of the current signal is duplicated. The output current signal of the second current replication circuit (double the same minimum reference current signal) and the minimum reference current signals from the two first current replication circuits are used as another second current replication circuit. Here, a quadruple of the same minimum reference current signal is duplicated. By duplicating in the same manner, the same minimum reference current signal multiplied by a power of 2 can be output from the second current replication circuit for outputting the reference current signal. As a result, n types of the reference current signals can be obtained.

  Unlike the prior art in which an accurate reference current signal cannot be obtained when there is a large difference in characteristics such as threshold voltage and electron mobility between thin film transistors constituting a current mirror circuit, according to the above invention, the same minimum reference current is always obtained. A signal flows from the first current replication circuit to the minimum reference current signal generation circuit, the minimum reference current signal is replicated and output, and the same minimum reference current signal multiplied by 2 is multiplied by n Can be output as a reference current signal.

  Thereby, it is possible to always generate an accurate reference current signal without being restricted by the characteristic difference between the thin film transistors. Therefore, the electro-optic element always has a desired luminance, and also has an effect that a desired image can be reliably obtained.

  The current discharge type current replication circuit of the first current replication circuit is configured to sample and hold the minimum reference current signal, and to discharge the sampled and held minimum reference current signal to the output terminal. Each of the second current duplicating circuits includes a second sample and hold unit that samples and holds a current signal flowing through the input terminal, and the second current duplicating circuit includes: The current discharge type current replication circuit of the replication circuit includes a third sample / hold unit that samples and holds a current signal flowing through the output unit of the current sink type current replication circuit, and the output of the sampled / held current signal It is preferable to include a third output unit that discharges to the terminal.

  The first sample and hold unit includes first and third TFTs of P or N channel, respectively. The first, second, and third TFTs sample the minimum reference current signal, and the third TFT samples the minimum sampled. A reference current signal is held through a first capacitor, and the first output unit includes third and fourth TFTs of P or N channel, and discharges the sampled and held minimum reference current signal, and the second sample. The hold unit is composed of P or N channel fifth to seventh TFTs. The fifth, sixth, and seventh TFTs sample current signals flowing through the input terminals, and the seventh TFT samples the sampled current signals. The third sample-and-hold unit is composed of P- or N-channel eighth to tenth TFTs, respectively, through a second capacitor. The eighth, ninth, and tenth TFTs sample the current signal held through the second capacitor, the tenth TFT holds the sampled current signal through the third capacitor, and the third output unit. Is preferably composed of P and N channel tenth and eleventh TFTs, and discharges the sampled and held current signal to the output terminal.

  As described above, the first and second current duplicating circuits are not configured as a current mirror circuit, so that the above effect can be obtained.

  Still another active drive type display device according to the present invention is connected to the minimum reference current signal generating circuit for generating the minimum reference current signal and to output the n kinds of reference current signals, as described above. A plurality of first current duplicating circuits comprising current sink type current duplicating circuits for duplicating the minimum reference current signal, and a plurality of current ejecting type current duplicating circuits and a current sink type current duplicating circuit connected in series. A second current duplicating circuit, wherein an output terminal of the first current duplicating circuit and an input terminal of the second current duplicating circuit are connected to each other, and the second current duplicating circuit is not used for outputting the n types of reference current signals The two-current replication circuit has an output terminal and an input terminal connected to each other, so that the minimum reference current signal does not flow to the two first current replication circuits at the same time. The quasi-current signal with flow respectively to said first current replication circuit, a second current duplication circuit for the output is characterized by sucking the n kinds of reference current signals, respectively.

  According to the above invention, an n-bit digital image signal is converted into a current signal based on n types of reference current signals output from the reference current generation circuit by the digital signal-current signal conversion circuit in the signal electrode driving circuit. Based on the converted current signal, the electro-optic elements are displayed in grayscale via the signal electrode drive circuit.

  Two first current duplicating circuits are provided, each of which consists of a current sink type current duplicating circuit, which sucks the minimum reference current signal and duplicates it. The second current replication circuit includes a pair of current discharge type current replication circuits and a current suction type current replication circuit connected in series, and a plurality of second current replication circuits are provided. The first and second current replication circuits are connected to output the n kinds of reference current signals.

  The minimum reference current signal is sent from the minimum reference current signal generation circuit to the first current replication circuit. Although the minimum reference current signal is supplied from the minimum reference current signal generation circuit to the first current replication circuit, the minimum reference current signal does not flow to the two first current replication circuits at the same time. As a result, since the same minimum reference current signal is always discharged from the minimum reference current signal generation circuit to the first current replication circuit, the same minimum reference current signal is replicated with high accuracy in each first current replication circuit. It becomes possible to do.

  On the other hand, the output terminal of the first current replication circuit and the input terminal of the second current replication circuit are connected to each other. The second current replication circuits are connected to each other at their input terminals. In addition, the second current duplicating circuit other than that for outputting the n types of reference current signals has an output terminal and an input terminal connected to each other.

  Due to this connection relationship, when a copy of the same minimum reference current signal is input from one of the second current replication circuits to two first current replication circuits, the same minimum reference current signal is obtained. A duplicate of the current signal is duplicated. The current signal flowing out from the second current replication circuit (double the same minimum reference current signal) and the minimum reference current signal sucked into the two first current replication circuits are the other second currents. When flowing out of the duplicating circuit, a quadruple of the same minimum reference current signal is duplicated here. By duplicating in the same manner, the same minimum reference current signal multiplied by a power of 2 can be sucked into the second current replication circuit for outputting the reference current signal. As a result, n types of the reference current signals can be obtained.

  Unlike the prior art in which an accurate reference current signal cannot be obtained when there is a large difference in characteristics such as threshold voltage and electron mobility between thin film transistors constituting a current mirror circuit, according to the above invention, the same minimum reference current is always obtained. A signal flows from the minimum reference current signal generation circuit to the first current replication circuit, the minimum reference current signal is replicated, and the same minimum reference current signal multiplied by 2 is the n reference currents. It can be output as a signal.

  Thereby, it is possible to always generate an accurate reference current signal without being restricted by the characteristic difference between the thin film transistors. Therefore, the electro-optic element always has a desired luminance, and also has an effect that a desired image can be reliably obtained.

  The current sink type current replication circuit of the first current replication circuit includes a first sample and hold unit that samples and holds the minimum reference current signal, and a first sample and hold unit that samples and holds the minimum reference current signal into the output terminal. Each of the second current duplicating circuits includes a second sample and hold unit that samples and holds a current signal flowing through an input terminal, and the second current duplicating circuit includes: The current sink type current duplicating circuit of the circuit includes a third sample and hold unit that samples and holds the current signal held by the second sample and hold unit, and the sample and hold current signal from the output terminal. The structure provided with the 3rd output part which inhales is preferable.

  The first sample and hold unit includes first and third TFTs of P or N channel, respectively. The first, second, and third TFTs sample the minimum reference current signal, and the third TFT samples the minimum sampled. A reference current signal is held through a first capacitor, and the first output unit includes third and fourth TFTs of P or N channel, and sucks in the sampled and held minimum reference current signal, and The hold unit is composed of P or N channel fifth to seventh TFTs. The fifth, sixth, and seventh TFTs sample current signals flowing through the input terminals, and the seventh TFT receives the sampled current signals. The third sample and hold unit is composed of P or N channel 8th to 10th TFTs, respectively. The eighth, ninth, and tenth TFTs sample the current signal held through the second capacitor, the tenth TFT holds the sampled current signal through the third capacitor, and the third output unit. Is preferably composed of 10th and 11th TFTs of P or N channel, and sucks the sampled and held current signal from the output terminal.

  As described above, the first and second current duplicating circuits are not configured as a current mirror circuit, so that the above effect can be obtained.

  Still another active drive type display device according to the present invention is connected to the minimum reference current signal generating circuit for generating the minimum reference current signal and to output the n kinds of reference current signals, as described above. It consists of two first current replication circuits composed of current discharge type current replication circuits that replicate the minimum reference current signal, a pair of current suction type current replication circuits and a current discharge type current replication circuit connected in series. A plurality of second current replication circuits, wherein an output terminal of the first current replication circuit and an input terminal of the second current replication circuit are connected to each other, and the second current replication circuit includes an output terminal and an input terminal. Are connected to each other, and the minimum reference current signal is generated from the first current replication circuit so that the minimum reference current signal does not flow from the two first current replication circuits at the same time. To with flow respectively, is characterized in that respectively output the n kinds of reference current signals from said first and second current replication circuit.

  According to the above invention, an n-bit digital image signal is converted into a current signal based on n types of reference current signals output from the reference current generation circuit by the digital signal-current signal conversion circuit in the signal electrode driving circuit. Based on the converted current signal, the electro-optic elements are displayed in grayscale via the signal electrode drive circuit.

  Two first current duplicating circuits are provided, each of which comprises a current discharge type current duplicating circuit, duplicating the minimum reference current signal and outputting it. The second current replication circuit includes a pair of current suction type current replication circuits and a current discharge type current replication circuit connected in series, and a plurality of second current replication circuits are provided. The first and second current replication circuits are connected to output the n kinds of reference current signals.

  The minimum reference current signal is sent from the first current replication circuit to the minimum reference current signal generation circuit. The minimum reference current signal flows from the first current replication circuit to the minimum reference current signal generation circuit, but at this time, the minimum reference current signal does not flow from the two first current replication circuits at the same time. As a result, since the same minimum reference current signal is always discharged from the first current replication circuit to the minimum reference current signal generation circuit, the same minimum reference current signal is replicated with high accuracy in each first current replication circuit. It becomes possible to do.

  On the other hand, the output terminal of the first current replication circuit and the input terminal of the second current replication circuit are connected to each other. In addition, the output terminal and the input terminal of the second current replication circuit are connected to each other.

  Due to this connection relationship, when a duplicate of the same minimum reference current signal is input from one of the two first current replication circuits to one of the second current replication circuits, the same minimum reference current A duplicate of the current signal is duplicated. The output current signal of the second current replication circuit (double the same minimum reference current signal) and the minimum reference current signals from the two first current replication circuits are used as another second current replication circuit. Here, a quadruple of the same minimum reference current signal is duplicated. By duplicating in the same manner, the same minimum reference current signal multiplied by a power of 2 can be output from the first and second current replication circuits. As a result, n types of the reference current signals can be obtained.

  Unlike the prior art in which an accurate reference current signal cannot be obtained when there is a large difference in characteristics such as threshold voltage and electron mobility between thin film transistors constituting a current mirror circuit, according to the above invention, the same minimum reference current is always obtained. A signal flows from the first current replication circuit to the minimum reference current signal generation circuit, the minimum reference current signal is replicated and output, and the same minimum reference current signal multiplied by 2 is multiplied by n Can be output as a reference current signal.

  Thereby, it is possible to always generate an accurate reference current signal without being restricted by the characteristic difference between the thin film transistors. Therefore, the electro-optic element always has a desired luminance, and also has an effect that a desired image can be reliably obtained.

  The current discharge type current replication circuit of the first current replication circuit is configured to sample and hold the minimum reference current signal, and to discharge the sampled and held minimum reference current signal to the output terminal. Each of the second current duplicating circuits includes a second sample and hold unit that samples and holds a current signal flowing through the input terminal, and the second current duplicating circuit includes: The current discharge type current duplicating circuit of the duplicating circuit includes a third sample-and-hold unit that samples and holds the current signal held by the second sample-and-hold unit, and the output terminal that receives the sample-held current signal. The structure provided with the 3rd output part discharged to is preferable.

  The first sample and hold unit includes first and third TFTs of P or N channel, respectively. The first, second, and third TFTs sample the minimum reference current signal, and the third TFT samples the minimum sampled. A reference current signal is held through a first capacitor, and the first output unit includes third and fourth TFTs of P or N channel, and discharges the sampled and held minimum reference current signal, and the second sample. The hold unit is composed of P or N channel fifth to seventh TFTs, the fifth, sixth and seventh TFTs sample the current signal flowing to the input terminal, and the seventh TFT captures the sampled current signal. The third sample-and-hold unit is composed of P- or N-channel eighth to tenth TFTs, respectively, through a second capacitor. The eighth, ninth, and tenth TFTs sample the current signal held through the second capacitor, the tenth TFT holds the sampled current signal through the third capacitor, and the third output unit. Is preferably composed of P and N channel tenth and eleventh TFTs, and discharges the sampled and held current signal to the output terminal.

  As described above, the first and second current duplicating circuits are not configured as a current mirror circuit, so that the above effect can be obtained.

  Still another active drive type display device according to the present invention is connected to the minimum reference current signal generating circuit for generating the minimum reference current signal and to output the n kinds of reference current signals, as described above. A plurality of first current duplicating circuits comprising current sink type current duplicating circuits for duplicating the minimum reference current signal, and a plurality of current ejecting type current duplicating circuits and a current sink type current duplicating circuit connected in series. A second current replication circuit, the output terminal of the first current replication circuit and the input terminal of the second current replication circuit are connected to each other, and the output terminal and the input terminal of the second current replication circuit are connected to each other. The minimum reference current signal is supplied from the minimum reference current signal generation circuit to the first current replication circuit so that the minimum reference current signal does not flow to the two first current replication circuits. With flow respectively, said first and second current replication circuit is characterized by sucking the n kinds of reference current signals, respectively.

  According to the above invention, an n-bit digital image signal is converted into a current signal based on n types of reference current signals output from the reference current generation circuit by the digital signal-current signal conversion circuit in the signal electrode driving circuit. Based on the converted current signal, the electro-optic elements are displayed in grayscale via the signal electrode drive circuit.

  Two first current duplicating circuits are provided, each of which consists of a current sink type current duplicating circuit, which sucks the minimum reference current signal and duplicates it. The second current replication circuit includes a pair of current discharge type current replication circuits and a current suction type current replication circuit connected in series, and a plurality of second current replication circuits are provided. The first and second current replication circuits are connected to output the n kinds of reference current signals.

  The minimum reference current signal is sent from the minimum reference current signal generation circuit to the first current replication circuit. Although the minimum reference current signal is supplied from the minimum reference current signal generation circuit to the first current replication circuit, the minimum reference current signal does not flow to the two first current replication circuits at the same time. As a result, since the same minimum reference current signal is always discharged from the minimum reference current signal generation circuit to the first current replication circuit, the same minimum reference current signal is replicated with high accuracy in each first current replication circuit. It becomes possible to do.

  On the other hand, the output terminal of the first current replication circuit and the input terminal of the second current replication circuit are connected to each other. In addition, the output terminal and the input terminal of the second current replication circuit are connected to each other.

  Due to this connection relationship, when a copy of the same minimum reference current signal is input from one of the second current replication circuits to two first current replication circuits, the same minimum reference current signal is obtained. A duplicate of the current signal is duplicated. The current signal flowing out from the second current replication circuit (double the same minimum reference current signal) and the minimum reference current signal sucked into the two first current replication circuits are the other second currents. When flowing out of the duplicating circuit, a quadruple of the same minimum reference current signal is duplicated here. In the same manner, the same minimum reference current signal multiplied by a power of 2 can be sucked into the first and second current duplicating circuits. As a result, n types of the reference current signals can be obtained.

  Unlike the prior art in which an accurate reference current signal cannot be obtained when there is a large difference in characteristics such as threshold voltage and electron mobility between thin film transistors constituting a current mirror circuit, according to the above invention, the same minimum reference current is always obtained. A signal flows from the minimum reference current signal generation circuit to the first current replication circuit, the minimum reference current signal is replicated, and the same minimum reference current signal multiplied by 2 is the n reference currents. It can be output as a signal.

  Thereby, it is possible to always generate an accurate reference current signal without being restricted by the characteristic difference between the thin film transistors. Therefore, the electro-optic element always has a desired luminance, and also has an effect that a desired image can be reliably obtained.

  The current sink type current replication circuit of the first current replication circuit includes a first sample and hold unit that samples and holds the minimum reference current signal, and a first sample and hold unit that samples and holds the minimum reference current signal into the output terminal. Each of the second current duplicating circuits includes a second sample and hold unit that samples and holds a current signal flowing through an input terminal, and the second current duplicating circuit includes: The current sink type current duplicating circuit of the circuit includes a third sample and hold unit that samples and holds a current signal flowing through the output unit of the current discharge type current duplicating circuit, and the output terminal that samples and holds the current signal It is preferable to provide the 3rd output part which inhales.

  The first sample and hold unit includes first and third TFTs of P or N channel, respectively. The first, second, and third TFTs sample the minimum reference current signal, and the third TFT samples the minimum sampled. A reference current signal is held through a first capacitor, and the first output unit includes third and fourth TFTs of P or N channel, and sucks in the sampled and held minimum reference current signal, and The hold unit is composed of P or N channel fifth to seventh TFTs. The fifth, sixth, and seventh TFTs sample current signals flowing through the input terminals, and the seventh TFT receives the sampled current signals. The third sample and hold unit is composed of P or N channel 8th to 10th TFTs, respectively. The eighth, ninth, and tenth TFTs sample the current signal held through the second capacitor, the tenth TFT holds the sampled current signal through the third capacitor, and the third output unit. Is preferably composed of 10th and 11th TFTs of P or N channel, and sucks the sampled and held current signal from the output terminal.

  As described above, the first and second current duplicating circuits are not configured as a current mirror circuit, so that the above effect can be obtained.

  The active drive type display device according to the present invention may have the following configuration, and even in this case, the same effects as described above are obtained.

  That is, another active drive type display device according to the present invention, as described above, has a plurality of current discharge type currents with a current discharge type current replication circuit replicating a current signal as a minimum reference as a minimum unit. It has a current discharge type reference current generation circuit that can generate a desired reference current signal by connecting duplicate circuits in parallel and generate a plurality of reference current signals. It may be characterized by being connected to a signal-current signal conversion circuit.

  As described above, another active drive type display device according to the present invention has a plurality of current sink type current duplicating circuits in parallel with a current sink type current duplicating circuit that duplicates a current signal as a minimum reference as a minimum unit. A current sink type reference current generation circuit that can generate a desired reference current signal by connecting to generate a plurality of reference current signals, and converts the plurality of reference current signals into a digital signal-current signal of a signal electrode drive circuit It may be characterized by being connected to a circuit.

  As described above, another active drive type display device according to the present invention includes a plurality of current discharge type current replication circuits that replicate a current signal that is a minimum reference, and a current suction type current replication circuit and a current discharge. A current discharge circuit that generates a current signal that is twice the minimum reference current signal by a plurality of current discharge type current replication circuits configured as a pair with the current-type current replication circuit, and holds each generated current signal A reference current generation circuit constituted by a sine-type current replication circuit may be provided, and the reference current signal may be connected to a digital signal-current signal conversion circuit of the signal electrode drive circuit.

  As described above, another active drive type display device according to the present invention includes a plurality of current suction type current replication circuits, a current discharge type current replication circuit, and a current suction type that replicate a current signal that is a minimum reference. Multiple current sink type current duplication circuits configured as a pair with the current duplication circuit generate a current signal that is twice the minimum reference current signal, and current sink type current to hold each generated double current signal A reference current generation circuit configured by a replica circuit may be provided, and the reference current signal may be connected to a digital signal-current signal conversion circuit of the signal electrode drive circuit.

  As described above, another active drive type display device according to the present invention includes a plurality of current discharge type current replication circuits that replicate a current signal that is a minimum reference, and a current suction type current replication circuit and a current discharge. Duplicate the current of double the current signal that is the minimum reference by a plurality of current discharge type current duplication circuits configured in pairs with the type current duplication circuit, and connect all the outputs of each current discharge type current duplication circuit, The output may be connected to a digital signal-current signal conversion circuit of the signal electrode driving circuit.

  As described above, another active drive type display device according to the present invention includes a plurality of current suction type current replication circuits, a current discharge type current replication circuit, and a current suction type that replicate a current signal that is a minimum reference. Duplicate current double the current signal that is the minimum reference by multiple current sink type current duplication circuits configured in pairs with the current duplication circuit, and connect all the outputs of each current sink type current duplication circuit, the output is The signal electrode driving circuit may be connected to a digital signal-current signal conversion circuit.

  In any one of the active drive display devices described above, it is preferable that the electro-optic element is an organic EL element as described above.

  One embodiment of the present invention is described below with reference to FIGS. 1 and 2A and 2B. In the following description, an active drive organic EL display device will be described as an example of the active drive display device, but the present invention is not limited to such an example.

  1 and 2 show a reference current generating circuit constituted by TFTs formed by using the polysilicon TFT technology according to the present embodiment. As shown in FIG. 1, this reference current generation circuit is mainly composed of a current sink type minimum reference current signal generation circuit 309 and a current discharge type current replication circuit 400.

  In the current sink type minimum reference current signal generating circuit 309, reference numeral 300 is a constant voltage circuit, which outputs a constant voltage. Reference numeral 301 denotes an operational amplifier such as an operational amplifier. A signal voltage is applied to the gate of the control N-channel transistor 302 so that the voltages generated in the reference resistor 303 are equal with respect to the output voltage from the constant voltage circuit 300. give. The reference resistor 303 is connected to the source side of the control N-channel transistor 302 via the reference voltage input terminal VREF.

  The control N-channel transistor 302 of the current sink type minimum reference current signal generation circuit 309 supplies a minimum reference current signal Is, which is a constant current, based on the output voltage from the constant voltage circuit 300 and the reference resistor 303.

  The drain of the control N-channel transistor 302 is connected to a 6-bit current discharge type current replication circuit 400. The current discharge type current duplication circuit 400 includes a plurality of current discharge type current duplication circuits 401 to 463. Details of each of the current discharge type current duplicating circuits 401 to 463 are shown in FIG. FIG. 2B is a model diagram showing an input current signal and an output current signal, omitting the control signal and detailed circuit in FIG. Note that the present invention is not limited to 6 bits.

  As shown in FIG. 2A, the current discharge type current duplicating circuits 401 to 463 are mainly composed of P-channel TFTs 391 to 394 and a capacitor 395, respectively. In the P-channel TFT 391, the drain is connected to the input terminal Iin of the input current signal, the gate is connected to the control terminal SS1 (terminal to input the control signal SS1) together with the gate of the P-channel TFT 392, and the source is the drain of the P-channel TFT 392. And the drain of the P-channel TFT 393 and the source of the P-channel TFT 394.

  The source of the P-channel TFT 392 is connected to the gate of the P-channel TFT 393 and the capacitor 395. The source of the P-channel TFT 393 is connected to the power supply Vcc, the gate of the P-channel TFT 394 is connected to the control terminal OS1 (terminal to which the control signal OS1 is input), and the drain is connected to the output terminal Iout that outputs a current signal. ing.

  2A is basically the same as the circuit of FIG. 15 except that the N-channel TFT of FIG. 15 is changed to a P-channel TFT, the power source is changed from GND to Vcc, and the control signal names are changed to SS1 and OS1. It is.

  By setting the control signal SS1 to “L” (low level) and the control signal OS1 to “H” (high level), the P-channel TFTs 391 and 392 are turned on and the P-channel TFT 394 is turned off. At this time, when the minimum reference current signal Is flows from the input terminal Iin which is the drain terminal of the P-channel TFT 391, a voltage necessary for the P-channel TFT 393 to flow the minimum reference current signal Is flows to the gate of the P-channel TFT 393. Occurs (sample operation). This voltage is held in the capacitor 395 (hold operation).

  Thereafter, by setting the control signal SS1 to “H”, the P-channel TFTs 391 and 392 are turned off. Thereafter, by changing the control signal OS1 from “H” to “L”, the reference current signal Is having the same value as the minimum reference current signal Is is duplicated and output from the drain side of the P-channel TFT 393.

  That is, each of the current discharge type current replication circuits 401 to 463 samples and holds a current signal flowing through the input terminal Iin, and replicates and outputs the current signal from the output terminal Iout. Is configured. With the circuit shown in FIG. 2A as the minimum unit, 63 current discharge type current duplicating circuits 401 to 463 are used in FIG. 1, and are drawn using the model diagram shown in FIG. Yes.

  The current discharge type current duplicating circuit 401 samples and holds the minimum reference current signal Is flowing between the drain and source of the control N-channel transistor 302, and duplicates and outputs the minimum reference current signal Is.

  The current discharge type current duplicating circuits 402 and 403 are connected to each other at their output units (output terminals). Each circuit samples and holds the minimum reference current signal Is, and is twice the minimum reference current signal Is. Duplicate and output current signal.

  The current discharge type current duplicating circuits 404 to 407 are connected to each other at their output units (output terminals). Each circuit samples and holds the minimum reference current signal Is, and the current signal is four times the minimum reference current signal Is. Duplicate Is × 4 and output.

  The current discharge type current duplicating circuits 408 to 415 are connected to each other at their output units (output terminals). Each circuit samples and holds the minimum reference current signal Is, and the current signal is eight times the minimum reference current signal Is. Duplicate Is × 8 and output.

  The current discharge type current duplicating circuits 416 to 431 are connected to each other at their output units (output terminals). Each circuit samples and holds the minimum reference current signal Is, and the current signal is 16 times the minimum reference current signal Is. Duplicate Is × 16 and output.

  The current discharge type current duplicating circuits 432 to 463 are connected at their output sections (output terminals). Each circuit samples and holds the minimum reference current signal Is, and the current signal Is is 32 times the minimum reference current signal Is. Duplicate x32 and output.

  Since two or more current discharge type current duplicating circuits 401 to 463 cannot sample and hold the minimum reference current signal Is simultaneously, for example, the current discharge type current duplicating circuits 401 to 463 sequentially sample and hold from 401 to 463, for example. Therefore, the control signal SS1 is a different control signal in each of the current discharge type current duplicating circuits 401 to 463.

  In the conventional current mirror circuit, if the characteristics of the two transistors constituting the current mirror do not match, the current on the input side does not match the current on the output side (current flowing through the two transistors). In the 6-bit current discharge type current duplicating circuit 400 according to the invention, the minimum reference current signal is duplicated by a current duplicating circuit in a minimum unit, for example, one transistor called the P-channel transistor 393 in FIG. Compared with the conventional type, the current replication accuracy is remarkably improved. As a result, minimum reference current signals (reference current signals) of powers of 2, which are 1 times, 2 times, 4 times, 8 times, 16 times, and 32 times, can be obtained with high accuracy. Therefore, it is possible to output six types of reference currents with high accuracy to the signal electrode drive circuit.

  As described above, the active drive type display device according to the present embodiment duplicates the minimum reference current signal Is, the current sink type minimum reference current signal generation circuit 309 that generates the minimum reference current signal Is, and the reference A plurality of current discharge type current duplicating circuits 401 to 463 for outputting a current signal, and the minimum reference current signal Is does not flow from two or more current discharge type current duplicating circuits at the same time during the sampling operation; In operation, the current discharge type current duplicating circuits 401 to 463 are configured to obtain the above six types of reference current signals by performing an output operation simultaneously or sequentially.

  According to the above configuration, the 6-bit digital image signal is converted into a current signal based on the six types of reference current signals output from the reference current generation circuit by the DCC 205 (see FIG. 13), and the signal electrode drive circuit (Not shown), the electro-optic elements are each displayed in grayscale based on the current signal thus converted.

  The current discharge type current duplicating circuits 401 to 463 are connected so that the six types of reference current signals (Is to Is × 32) are output from the reference current generating circuit, and the duplicating circuits 401 to 463 are respectively connected. The minimum reference current signal Is is duplicated, and the duplicated minimum reference current signal Is is output. Since the duplication circuits 401 to 463 are connected as described above, the duplicated minimum reference current signal is output from each of the current discharge type current duplication circuits 401 to 463, so that the above six types of reference are obtained as a whole. A current signal (Is to Is × 32) is obtained.

  During the replication, the minimum reference current signal Is is supplied from the current discharge type current replication circuits 401 to 463 to the minimum reference current signal generation circuit 309. At this time, since the minimum reference current signal Is does not flow from two or more current discharge type current duplication circuits at the same time, the same minimum reference current signal Is is always sent from the current discharge type current duplication circuits 401 to 463 to the minimum reference current signal. As a result, the same minimum reference current signal Is can be duplicated with high accuracy in each of the duplicating circuits 401 to 463.

  Unlike the prior art in which an accurate reference current signal cannot be obtained when there is a large difference in characteristics such as threshold voltage and electron mobility between thin film transistors that constitute a current mirror circuit, the above configuration always ensures that the same minimum reference current is obtained. The signal Is flows from the current discharge type current duplication circuits 401 to 463 to the minimum reference current signal generation circuit 309, and the current discharge type current duplication circuits 401 to 463 duplicate and output the minimum reference current signal Is. The

  Thereby, it is possible to always generate an accurate reference current signal without being restricted by the characteristic difference between the thin film transistors. Therefore, it is possible to always obtain a desired luminance in the electro-optic element, and it is possible to reliably obtain a desired image.

  In the above description, the case where the circuit of FIG. 2A configured by P-channel TFTs is employed as the minimum unit of the current discharge type current duplicating circuits 401 to 463 has been described. However, the present invention is not limited to this. However, as long as the same operation is performed, one part or all of them may be composed of N-channel TFTs.

  Further, when the 6-bit DCC circuit of the signal electrode driving circuit is a current sink type circuit as shown in FIG. 14, a current discharge type current replication circuit as shown in FIG. 2A is obtained, but the 6-bit DCC circuit is a current discharge type circuit. In this case, it becomes as shown in FIG. 3, FIG. 4 (a), and FIG. 4 (b). 3, 4 (a), and 4 (b), members having the same functions as those in FIGS. 1, 2 (a), and 2 (b) are denoted by the same reference numerals, Detailed description is omitted.

  In FIG. 4A, by setting the control signal SS1 to “H” (high level) and the control signal OS1 to “L” (low level), the N-channel TFTs 391 and 392 are turned on and the N-channel TFT 394 is turned off. become. At this time, when the minimum reference current signal Is is input to the input terminal Iin which is the drain terminal of the N-channel TFT 391, it is necessary for the N-channel TFT 393 to flow the minimum reference current signal Is to the gate of the N-channel TFT 393. Voltage is generated (sample operation). This voltage is held in the capacitor 395 (hold operation).

  Thereafter, the N-channel TFTs 391 and 392 are turned off by setting the control signal SS1 to “L”. After that, by changing the control signal OS1 from “L” to “H”, the reference current signal Is having the same value as the minimum reference current signal Is is sucked from the drain side of the N-channel TFT 393 and duplicated.

  That is, a current sink type current replication circuit is configured that samples and holds the minimum reference current signal from the input terminal Iin and sucks the same current signal as the minimum reference current signal Is from the output terminal Iout. With the circuit shown in FIG. 4A as a minimum unit, 63 current sink type current duplicating circuits 401 to 463 are used in FIG. 3 and are drawn using the model diagram shown in FIG. .

  The current sink type current duplicating circuit 401 samples and holds (duplicates) the minimum reference current signal Is flowing between the drain and source of the control P-channel transistor 302 and sucks the minimum reference current signal Is.

  The current sink type current duplicating circuits 402 and 403 are connected to each other at their output parts (output terminals). Each circuit samples and holds the minimum reference current signal Is, and the current is twice the minimum reference current signal Is. Inhale and replicate signals.

  The current sink type current duplicating circuits 404 to 407 are connected to each other at their output units (output terminals). Each circuit samples and holds the minimum reference current signal Is, and the current signal Is is four times the minimum reference current signal Is. Inhale x4 and replicate.

  The current sink type current duplicating circuits 408 to 415 are connected to each other at their output units (output terminals). Each circuit samples and holds the minimum reference current signal Is, and the current signal Is is eight times the minimum reference current signal Is. Inhale x8 and replicate.

  The current sink type current duplicating circuits 416 to 431 are connected to each other at their output units (output terminals). Each circuit samples and holds the minimum reference current signal Is, and the current signal Is is 16 times the minimum reference current signal Is. Inhale x16 and replicate.

  The current sink type current duplicating circuits 432 to 463 are connected at their output sections (output terminals). Each circuit samples and holds the minimum reference current signal Is, and the current signal Is × 32 times the minimum reference current signal Is × 32 is sucked in and replicated.

  3 cannot simultaneously sample and hold the minimum reference current signal Is, for example, sequentially sample and hold from 401 to 463. Therefore, the control signal SS1 is a different control signal in the current sink type current duplicating circuits 401 to 463.

  In the current sink type current replication circuit 400 for 6 bits shown in FIG. 3, the number of transistors that replicate the current (minimum reference current signal) is one, unlike the current mirror type conventional circuit. The circuit shown in FIG. 4A having good accuracy is set as the minimum unit. As a result, minimum reference current signals of powers of 2, which are 1 times, 2 times, 4 times, 8 times, 16 times, and 32 times, can be obtained with high accuracy, and based on these, 6-bit data signals are converted into current signals. Therefore, it is possible to generate six types of reference currents with high accuracy for the signal electrode drive circuit.

  As described above, the active drive display device according to the present embodiment duplicates the minimum reference current signal Is and the minimum reference current signal generation circuit 309 that generates the minimum reference current signal Is, and the n types of reference signals. A plurality of current sink type current duplicating circuits 401 to 463 connected to suck current signals, and the minimum reference current signal Is is not sucked by two or more current sink type current duplicating circuits at the same time. The minimum reference current signal Is is supplied from the current signal generation circuit 309 to the current sink type current duplicating circuits 401 to 463 and duplicated, and the minimum reference current signal Is replicated to the current sink type current duplicating circuits 401 to 463 is obtained. Inhalation is performed to obtain the above six types of reference current signals.

  According to the above configuration, the 6-bit digital image signal is converted into a current signal based on the six types of reference current signals output from the reference current generation circuit by the DCC 205 (see FIG. 13), and the signal electrode drive circuit (Not shown), the electro-optic elements are each displayed in grayscale based on the current signal thus converted.

  The current sink type current duplicating circuits 401 to 463 are connected so that the above six types of reference current signals (Is to 32 × Is) are sucked, and the duplicating circuits 401 to 463 are connected to the minimum and minimum reference current signals. Duplicate Is and suck in the duplicated minimum reference current signal Is. Since each duplicating circuit 401 to 463 is connected as described above, the duplicated minimum reference current signal Is flows to each current sink type current duplicating circuit 401 to 463, so that the six kinds of reference current signals as a whole. Will be obtained.

  During the duplication, the minimum reference current signal Is is supplied from the minimum reference current signal generation circuit 309 to the current sink type current duplication circuits 401 to 463, respectively. At this time, since the minimum reference current signal Is does not flow to two or more current sink type current replication circuits at the same time, the same minimum reference current signal Is is always supplied from the minimum reference current signal generation circuit 309 to the current sink type current replication circuit. In this way, the same minimum reference current signal Is can be duplicated with high accuracy in each of the duplicating circuits 401 to 463.

  Unlike the prior art in which an accurate reference current signal cannot be obtained when there is a large difference in characteristics such as threshold voltage and electron mobility between thin film transistors that constitute a current mirror circuit, the above configuration always ensures that the same minimum reference current is obtained. The signal Is flows from the minimum reference current signal generating circuit 309 to the current sink type current duplicating circuits 401 to 463, respectively, and the current sink type current duplicating circuits 401 to 463 are sucked and duplicated.

  Thereby, it is possible to always generate an accurate reference current signal without being restricted by the characteristic difference between the thin film transistors. Therefore, it is possible to always obtain a desired luminance in the electro-optic element, and it is possible to reliably obtain a desired image.

  In the above description, the case where the circuit of FIG. 4 (a), which is composed of all N-channel TFTs, is used as the minimum unit of the current sink type current replication circuits 401 to 463 has been described. However, the present invention is not limited to this. However, as long as the same operation is performed, one part or all of them may be composed of P-channel TFTs.

  As described above, with respect to the operation, the operation of the configuration shown in FIG. 1, FIG. 2A, and FIG. Here, four TFTs are used as a current sinking type or current discharging type current duplicating circuit. However, the number of transistors for duplicating the current is one instead of two as in the current mirror type circuit. Any TFT may be used as long as it is configured, and there is no problem as long as the current replication function is working even if TFTs such as other switches are added or deleted, or signal electrodes and power supply lines are added.

  FIG. 5 shows an example of a reference current generating circuit composed of TFTs formed using polysilicon TFT technology according to still another embodiment of the present invention. The current sink type minimum reference current signal generation circuit 309 is the same as that shown in FIG.

  In the current signal replication circuits A10 and A20, the input terminal I1in is connected to the drain of the N-channel transistor 302, and the output terminal I1out is connected by a common line. After sampling and holding the minimum reference current signal Is flowing between the source and drain of the N-channel transistor 302, the minimum reference current signal Is is duplicated and output.

  In the current signal duplication circuits B30, B60, B70, and B80, the input terminals I2in, I4in, I8in, and I16in and the current signal output terminals I2out, I4out, I8out, and I16out are output terminals I1out of the current signal duplication circuits A10 and A20. And connected in common.

  In the current signal duplication circuits B90 to B140, input terminals I1in, I2in, I4in, I18in, I16in, and I32in are connected to the common line, and signals are output from the output terminals I1out, I2out, I4out, I8out, I16out, and I32out. A reference current signal is generated for the electrode driving circuit.

  Here, the operation of the circuit of FIG. 5 will be described with reference to FIGS. 6 and 7 as follows.

  FIG. 6 shows in detail the circuits of the current signal replication circuits A10, A20, and B30 of FIG. The current signal duplicating circuit A10 has the same circuit configuration as that shown in FIG. 2A. The input terminal I1in for inputting the current signal is connected to the drain of the control N-channel transistor 302, and is controlled by the control signal SS1 and the control signal OS1. Be controlled.

  The current signal duplication circuit A20 has the same configuration as the current signal duplication circuit A10, is controlled by the signals of the control signal SS2 and the control signal OS2, and the current signal duplication circuit A10 has inputs and outputs that are electrically connected to each other. Connected in parallel.

  The current signal replication circuit B30 includes a current discharge type current signal replication circuit 50 and a current suction type current signal replication circuit 40. The current discharge type current signal replication circuit 50 is the same current discharge type current signal replication circuit as the current signal replication circuit A10, and is controlled by the signals of the control signal TS3 and the control signal OS3. The current sink type current signal duplicating circuit 40 is a current sink type current duplicating circuit having a configuration opposite in polarity to the current discharging type current signal duplicating circuit 50 and the current signal duplicating circuit A10 and having no output control transistor, and the control signal SS3. Controlled by.

  In the current signal replication circuit A10, the control signal SS1 signal is set to “L” and the control signal OS1 is set to “H”, so that the minimum reference current signal Is from the current sink type minimum reference current signal generation circuit 309 is replicated as a current signal. The signal is copied in the circuit A10, and the control signal SS1 is set to “H”. Thereafter, in the current signal duplicating circuit A20, the control signal SS2 is set to “L” and the control signal OS2 is set to “H”, whereby the minimum reference current signal Is from the current sink type minimum reference current signal generating circuit 309 is duplicated. The control signal SS2 is set to “H” by duplicating in the circuit A20.

  Thereafter, by setting the control signal OS1 and the control signal OS2 to “L”, the minimum reference current signal Is is output from the current signal replication circuit A10, and the minimum reference current signal Is is also output from the current signal replication circuit A20. Is done. At the same time, the current signal (minimum reference current signal Is × 2) output from the current signal duplication circuits A10 and A20 is set to the current sink type by setting the control signal SS3 of the current sink type current signal duplication circuit 40 to “H”. In the current signal duplicating circuit 40, the control signals OS1 and OS2 are set to “H” and the control signal SS3 is set to “L”.

  Thereafter, in the current discharge type current signal replication circuit 50, the control signal TS3 is set to “L”, so that the current signal replicated in the current suction type current signal replication circuit 40 is output in the current discharge type current signal replication circuit 50. Copying is performed, and the control signal TS3 is set to “H”. Then, by setting the control signals OS1, OS2, and OS3 to “L” at the same time, the current signal duplicating circuits A10 and A20 output the minimum reference current signal Is, and the current signal duplicating circuit B30 outputs the minimum reference current signal Is. A × 2 current signal is output. As a result, the minimum reference current signal Is × 4 flows through the common line, and this signal is further duplicated.

  FIG. 7 shows the operation timing for sequentially copying the minimum reference current signal in this way. In FIG. 7, the vertical direction indicates a control signal, and the horizontal direction indicates time. In this drive timing, “◯” indicates that the transistor connected to the control signal is on, blank indicates an off operation, and “Δ” indicates that the transistor may be on or off. The above operation shows the operation from time 1 to time 5.

  Here, the operation of the circuit of FIG. 5 will be described with reference to FIG. At time 5, the minimum reference current signal Is is output from the current signal replication circuits A10 and A20, the minimum reference current signal Is × 2 is output from the current signal replication circuit B30, and the control signal SS4 is activated, whereby the current signal replication circuit B60 is activated. The current signal of the minimum reference current signal Is × 4 is duplicated.

  At time 6, a current signal is duplicated from a current suction type circuit (not shown) in the current signal duplication circuit B60 to a current discharge type circuit (not shown), and at time 7, the minimum reference current signal Is × Eight current signals are replicated.

  Further, at time 8, the current signal is replicated from a current sink type circuit (not shown) in the current signal duplication circuit B 60 to a current discharge type circuit (not shown), and at time 9, the minimum reference current signal Is × 16 is sent to the circuit 80. Current signals are replicated.

  At time 10, the current signal is replicated from the current suction type circuit (not shown) in the current signal replication circuit B80 to the current discharge type circuit (not shown). At time 11, the minimum reference current signal Is is output from the current signal replication circuit A10 and is replicated to the current signal replication circuit B90.

  At time 12, the current signal is replicated from the current suction type circuit (not shown) in the current signal replication circuit B90 to the current discharge type circuit (not shown). At time 13, the minimum reference current signal Is is output from the current signal duplicating circuits A10 and 20, and the minimum reference current signal Is × 2 is duplicated in the current signal duplicating circuit B100.

  At time 14, a current signal is replicated from a current sink type circuit (not shown) in the current signal replication circuit B100 to a current discharge type circuit (not shown). At time 15, the minimum reference current signal Is is output from the current signal replication circuit A10 / 20, the minimum reference current signal Is × 2 is output from the current signal replication circuit B30, and the minimum reference current signal Is × 4 is output to the current signal replication circuit B110. Is duplicated.

  At time 16, a current signal is replicated from a current suction type circuit (not shown) in the current signal replication circuit B110 to a current discharge type circuit (not shown). At time 17, the minimum reference current signal Is is output from the current signal replication circuit A10 / 20, the minimum reference current signal Is × 2 is output from the current signal replication circuit B30, and the minimum reference current signal Is × 4 is output from the current signal replication circuit B60. Is output, and the minimum reference current signal current signal Is × 8 is duplicated in the current signal duplication circuit B120.

  At time 18, a current signal is replicated from a current suction type circuit (not shown) in the current signal replication circuit B120 to a current discharge type circuit (not shown). At time 19, the minimum reference current signal Is is output from the current signal replication circuit A10 / 20, the minimum reference current signal Is × 2 is output from the current signal replication circuit B30, and the minimum reference current signal Is × 4 is output from the current signal replication circuit B60. Is output, the minimum reference current signal Is × 8 is output from the current signal replication circuit B70, and the minimum reference current signal Is × 16 is replicated in the current signal replication circuit B130.

  At time 20, the current signal is replicated from the current suction type circuit (not shown) in the current signal replication circuit B130 to the current discharge type circuit (not shown).

  At time 21, the minimum reference current signal Is is output from the current signal replication circuit A10 / 20, the minimum reference current signal Is × 2 is output from the current signal replication circuit B30, and the minimum reference current signal Is × 4 is output from the current signal replication circuit B60. Is output, the minimum reference current signal Is × 8 is output from the current signal replication circuit B70, the minimum reference current signal Is × 16 is output from the current signal replication circuit B130, and the minimum reference current signal Is × is output to the current signal replication circuit B140. 32 is duplicated. At time 22, a current signal is replicated from a current suction type circuit (not shown) in the current signal replication circuit B140 to a current discharge type circuit (not shown).

  In this way, six types of reference current signals to be supplied to the signal electrode drive circuit can be prepared. At time 23, 6 types of reference currents are output to the DCC circuit of the first line in the signal electrode drive circuit, and the DCC circuit duplicates the current signal. At time 24, the second line, at time 25, the third line, at time K The reference current is sequentially replicated in the Nth line and each DCC circuit. It should be noted that during the period from the time 23 to the time K, the operations performed at the times 1 to 10 may be repeated at the same time.

  FIG. 7 illustrates the case where the current signal duplicating circuits B90 to B140 output simultaneously, but the present invention is not limited to this. For example, the current signal duplicating circuits B90 to B140 output sequentially. The structure to do may be sufficient.

  In this way, in a circuit composed of a polycrystalline Si thin film, a current signal that is twice, four times, eight times, sixteen times, thirty-two times and twice the minimum reference current signal by a current duplicating circuit more accurate than the current mirror circuit. By duplicating the signal signal, the duplicated current signal is transmitted in parallel to the signal electrode driving circuit, thereby providing a highly accurate reference current generating circuit.

  In the above description, the minimum unit of the current discharge type current duplicating circuit is composed of P-channel TFTs and the current sink type current duplicating circuit is composed of all N channels. If there is a function of replicating the current signal, there is no limitation on the polarity of the N channel or the P channel.

  As described above, the active drive display device according to the present embodiment outputs the minimum reference current signal generation circuit 309 that generates the minimum reference current signal Is and the six types of reference current signals (Is to 32 × Is). And two first current signal duplication circuits (A10, A20) each composed of a current discharge type current duplication circuit that duplicates the minimum reference current signal Is, and a pair of current sinks connected in series. A plurality of second current signal replication circuits (B30 and B60 to B140) including a current-type current replication circuit 40 and a current discharge-type current replication circuit 50, and an output terminal I1out of the first current signal replication circuit and the first current signal replication circuit. The two current signal replication circuit input terminals (I1in, I2in, I4in, I8in, I16in, and I32in) are connected to each other, and the above six types of reference The second current signal duplicating circuits B60 to B80 other than those for outputting the current signal are connected to the output terminal and the input terminal, respectively, so that the minimum reference current signal Is does not flow from the two first current signal duplicating circuits at the same time. The minimum reference current signal Is is supplied from the first current signal replication circuit to the minimum reference current signal generation circuit 309, and the six types of reference currents are output from the output second current signal replication circuits B90 to B140. It has the structure which outputs each signal.

  According to the above configuration, a 6-bit digital image signal is converted into a current signal based on the six types of reference current signals output from the reference current generation circuit by the digital signal-current signal conversion circuit in the signal electrode drive circuit. Based on the converted current signal, the electro-optic elements are displayed in grayscale via the signal electrode drive circuit.

  Two first current replication circuits (A10 and A20) are provided, each of which is composed of a current discharge type current replication circuit, which replicates and outputs the minimum reference current signal Is. The second current replication circuits B30 and B60 to B140 are composed of a pair of current suction type current replication circuits 40 and current discharge type current replication circuits 50 connected in series, and a plurality of second current replication circuits B30 and B60 to B140 are provided. The first and second current signal duplicating circuits B30 and B60 to B140 are connected to output six types of reference current signals, respectively.

  The minimum reference current signal Is is supplied from the first current signal duplicating circuit (A10 / A20) to the minimum reference current signal generating circuit 309. The minimum reference current signal Is is supplied from the first current signal replication circuit to the minimum reference current signal generation circuit 309. At this time, the minimum reference current signal Is is simultaneously supplied from the two first current signal replication circuits. Absent. As a result, the same minimum reference current signal Is is always discharged from the first current signal replication circuit (A10 / A20) to the minimum reference current signal generation circuit 309, so that the first current signal replication circuit (A10 / A20) is discharged. ), The minimum reference current signal Is can be duplicated with high accuracy.

  Meanwhile, the output terminal I1out of the first current signal replication circuit and the input terminals (I1in, I2in, I4in, I8in, I16in, and I32in) of the second current signal replication circuit (B30 and B60 to B140) are connected to each other. ing. The second current signal replication circuits are connected to each other at their input terminals. In addition, in the second current signal duplicating circuits (B60 to B80) other than those for outputting the reference current signal corresponding to each bit, the output terminals (I4out, I8out, and I16out) and the input terminals (I4in, I8in, and I16in) ) Are connected to each other.

  Due to this connection relationship, a copy of the same minimum reference current signal Is is transferred from the two first current signal replication circuits (A10, A20) to one of the second current signal replication circuits (for example, B30). When input, here, a duplicate of the same minimum reference current signal Is is duplicated. The output current signal of the second current signal replication circuit (B30) (I2: the same minimum reference current signal multiplied by 2) and the minimum from the two first current signal replication circuits (A10 and A20) When the reference current signal Is is input to another second current signal duplicating circuit (for example, B60), a quadruple of the same minimum reference current signal is duplicated here. In the same manner, the same minimum reference current signal multiplied by a power of 2 can be output from the second current signal replication circuit (B90 to B140) for outputting the reference current signal. This makes it possible to obtain six types of the reference current signals (Is to 32 × Is).

  Unlike the prior art in which an accurate reference current signal cannot be obtained when there is a large difference in characteristics such as threshold voltage and electron mobility between thin film transistors constituting a current mirror circuit, according to the above invention, the same minimum reference current is always obtained. The signal Is flows from the first current duplicating circuit (A10 / A20) to the minimum reference current signal generating circuit 309, and the minimum reference current signal Is is duplicated and output. It is possible to output a power multiplied by a reference current signal.

  As a result, an accurate reference current signal can always be generated and supplied to the DCC 205 without being restricted by the characteristic difference between the thin film transistors. Therefore, it is possible to always obtain a desired luminance in the electro-optic element, and it is possible to reliably obtain a desired image.

  When the 6-bit DCC circuit of the signal electrode driving circuit is a current sink type circuit as shown in FIG. 14, a current discharge type current duplicating circuit such as the current signal duplicating circuit A10 in FIG. 6 and a current signal duplicating circuit B30 are used. The current suction type and the current discharge type are combined. However, when the 6-bit DCC circuit is a current discharge type circuit, the circuit configuration is as shown in FIGS. Since the operation is the same as that shown in FIGS. 5 and 6 except that the direction of current flow is reversed, the description thereof will be omitted.

  Here, four TFTs are used as a current sinking type or current discharging type current duplicating circuit. However, the number of transistors for duplicating the current is one instead of two as in the current mirror type circuit. If it is configured, there is no problem as long as the current replication function works even if TFTs such as other switches are added or deleted, or signal electrodes and power supply lines are added.

  FIG. 10 shows a reference current generating circuit composed of TFTs formed using polysilicon TFT technology according to still another embodiment of the present invention. This circuit has a circuit configuration in which the current signal duplication circuits B90 to 140 in the circuit of FIG. 5 are removed.

  The operation of the circuit of FIG. 10 will be described with reference to FIG. From time 1 to time 10, the minimum reference current signal Is generated by the minimum reference current signal generation circuit 309 is duplicated to the current signal duplication circuits A10 and A20 as in FIG. 7, and the current signal duplication circuit B30 produces the minimum reference current signal Is × 2, the current signal duplicating circuit B60 duplicates the minimum reference current signal Is × 4, the current signal duplicating circuit B70 duplicates the minimum reference current signal Is × 8, and the current signal duplicating circuit B60 duplicates the minimum reference current signal Is. X16 is duplicated.

  After duplicating the current signal in the current signal duplicating circuits A10 and A20 and the current signal duplicating circuits B30, B60, B70, and B80, the reference current signal is duplicated to the DCC 205 in the signal electrode driving circuit from time 11. To go.

  At time 11, the minimum reference current signal Is of the first line in the signal electrode driving circuit is duplicated in the DCC 205, at time 12, the minimum reference current signal Is × 2 is duplicated, and at time 13, the minimum reference current signal Is × 4. , And at time 14 the minimum reference current signal Is × 8 is replicated, at time 15 the minimum reference current signal Is × 16 is replicated, and at time 16 the minimum reference current signal Is × 32 is replicated. At time 17, Is, which is the minimum reference current signal for the second line, is replicated in the DCC circuit, and the minimum reference current signal Is × 32 for line N is sequentially replicated.

  As described above, in a circuit composed of a polycrystalline Si thin film, a current signal duplicating circuit more accurate than a current mirror circuit can generate a current signal that is twice, four times, eight times, sixteen times and twice the minimum reference current signal Is. By duplicating and transmitting the duplicated current signal to the signal electrode driving circuit in series, a highly accurate reference current generating circuit can be provided, and a more accurate reference current signal can be provided for the number of transistors in FIG. It is possible to copy the data with less than FIG.

  In the above description, the minimum unit of the current discharge type current duplicating circuit is composed of P-channel TFTs, and the current sink type current duplicating circuit is composed of all N channels. However, as the current discharge type or current sink type, If there is a function of replicating the current signal, the polarity of the N channel or P channel is not limited.

  Further, unlike the configuration of FIG. 7, in the configuration of FIG. 10, the current signal duplication circuits A10, A20, B30, and B60 to B80 cannot output simultaneously.

  As described above, the active drive display device according to the present embodiment includes the minimum reference current signal generation circuit 309 that generates the minimum reference current signal Is and the current discharge type current replication that replicates the minimum reference current signal Is. A plurality of second current signal duplication circuits comprising two first current signal duplication circuits A10 and A20 each comprising a circuit, and a pair of current suction type current duplication circuits 40 and a current discharge type current duplication circuit 50 connected in series. B30 and B60 to B80, and the output terminals I1out of the first current signal duplication circuits A10 and A20 and the input terminals (I2in, I4in, I8in, and I16in) of the second current signal duplication circuit are connected to each other. In addition, the second current signal replication circuit includes an output terminal (I2out, I4out, I8out, and I16out) and an input terminal (I2in). I4in, I8in, and I16in) are connected to each other, and the minimum reference current signal Is from the first current signal replication circuit (A10 / A20) is prevented from flowing simultaneously from the two first current signal replication circuits. The signal Is is supplied to the minimum reference current signal generation circuit 309, and six types of reference current signals (Is to 32 × Is) are output from the first and second current signal replication circuits.

  According to the above configuration, the 6-bit digital image signal is converted into a current signal based on the six types of reference current signals output from the reference current generation circuit by the DCC 205 in the signal electrode driving circuit, and the signal electrode driving is performed. Through the circuit, the electro-optic elements are displayed in gradation based on the current signal thus converted.

  Two first current signal replicating circuits are provided, each of which is composed of a current discharge type current replicating circuit, replicating the minimum reference current signal Is and outputting it. The second current signal replication circuit includes a pair of current suction type current replication circuit 40 and current discharge type current replication circuit 50 connected in series, and a plurality of second current signal replication circuits are provided. The first and second current signal replicating circuits are connected to output six types of reference current signals, respectively.

  The minimum reference current signal Is is supplied from the first current replication circuit (A10 / A20) to the minimum reference current signal generation circuit 309. The minimum reference current signal Is is supplied from the first current replication circuit (A10 / A20) to the minimum reference current signal generation circuit 309. At this time, the minimum reference current signal Is is simultaneously output from the two first current replication circuits. There is no flow. As a result, the same minimum reference current signal Is is always discharged from the first current replication circuit (A10 / A20) to the minimum reference current signal generation circuit 309. Therefore, in the first current replication circuit (A10 / A20) It becomes possible to replicate the same minimum reference current signal Is with high accuracy.

  On the other hand, the output terminal (I1out) of the first current replication circuit and the input terminals (I2in, I4in, I8in, and I16in) of the second current replication circuit are connected to each other. In addition, the second current replication circuit (B30 and B60 to B80) has an output terminal (I2out, I4out, I8out, and I16out) and an input terminal (I2in, I4in, I8in, and I16in) connected to each other.

  Due to this connection relationship, a copy of the same minimum reference current signal Is is input from two first current replication circuits (A10, A20) to one of the second current replication circuits (for example, B30). Then, here, a duplicate of the same minimum reference current signal Is is duplicated. The output current signal of the second current replication circuit (for example, B30) (double the same minimum reference current signal) and the minimum reference current from the two first current replication circuits (A10 and A20) When the signal Is is input to another second current duplicating circuit (for example, B60), the quadruple of the same minimum reference current signal Is is duplicated here. By duplicating in the same manner, the same minimum reference current signal Is multiplied by 2 can be output from the first and second current duplicating circuits. This makes it possible to obtain each of the six types of reference current signals.

  Unlike the prior art in which an accurate reference current signal cannot be obtained when there is a large difference in characteristics such as threshold voltage and electron mobility between thin film transistors constituting a current mirror circuit, according to the above invention, the same minimum reference current is always obtained. A signal flows from the first current duplicating circuit (A10 / A20) to the minimum reference current signal generating circuit 309, and the minimum reference current signal Is is duplicated and output, and the same minimum reference current signal Is is set to 2. It is possible to output a power multiplied by a reference current signal.

  Thereby, it is possible to always generate an accurate reference current signal without being restricted by the characteristic difference between the thin film transistors. Therefore, it is possible to always obtain a desired luminance in the electro-optic element, and it is possible to reliably obtain a desired image.

  Further, when the 6-bit DCC circuit of the signal electrode driving circuit is a current sink type circuit as shown in FIG. 14, a current discharge type current duplicating circuit such as the current signal duplicating circuit A10 of FIG. 6 and a current such as the current signal duplicating circuit B30 are shown. The combination of the suction type and the current discharge type is shown in FIGS. 12 and 9 when the 6-bit DCC circuit is a current discharge type circuit. Since the operation is the same as that shown in FIGS. 10 and 6 except that the direction of current flow is reversed, the description thereof will be omitted.

  Here, four TFTs are used as a current sinking type or current discharging type current duplicating circuit. However, the number of transistors for duplicating the current is one instead of two as in the current mirror type circuit. If it is configured, there is no problem as long as the current replication function works even if TFTs such as other switches are added or deleted, or signal electrodes and power supply lines are added.

  As described above, the pixel TFT, the signal electrode drive circuit, the scan electrode drive circuit, and the reference current generation circuit are formed on the same substrate plane by the polysilicon TFT technology according to the present invention, and the electro-optical element is driven at a constant current. In the reference current generating circuit of the type display device, a current sucking type or current discharging type current signal duplicating circuit that duplicates the minimum reference current signal is connected in parallel as a minimum unit, and a current that is a multiple of the minimum reference current signal Since a signal is obtained, a plurality of highly accurate reference currents can be generated, and an accurate current signal corresponding to input image data can be obtained, so that a desired image on a display device can be obtained.

  Also, an active drive type display device in which a pixel circuit, a signal electrode drive circuit, a scan electrode drive circuit, and a reference current generation circuit are formed on the same substrate plane by using the polysilicon TFT technology according to another invention, and the electro-optic element is driven at a constant current. In the reference current generating circuit, the current sink type or current discharge type current signal duplicating circuit that duplicates the minimum reference current signal, the current sink type current duplicating circuit, and the current discharging type current duplicating circuit are combined into a current sink type or By using a current discharge type double current duplication circuit, the current signal is duplicated as a double current signal, and the duplicated current signal is further duplicated by a current suction type or current discharge type double current duplication circuit. By sequentially doubling the reference current signal, the reference current signal is generated by double, quadruple, eight times, and sixteen times, and each current signal is further duplicated to generate the reference current source. Since it is, it is possible to generate a highly accurate reference current, in order to correct the current signal corresponding to the input image data is obtained, the image is obtained a desired display device. In addition, since the circuit can be configured with a small number of TFTs used, the overall glass size can be reduced by reducing the circuit area of the reference current generating circuit arranged in the peripheral area other than the display screen, and the display device can be downsized. In addition, since the circuit area is reduced, the yield of the display panel is improved, and the cost can be reduced.

  Also, an active drive type display device in which a pixel circuit, a signal electrode drive circuit, a scan electrode drive circuit, and a reference current generation circuit are formed on the same substrate plane by using the polysilicon TFT technology according to another invention, and the electro-optic element is driven at a constant current. In the reference current generating circuit, the current sink type or current discharge type current signal duplicating circuit that duplicates the minimum reference current signal, the current sink type current duplicating circuit, and the current discharging type current duplicating circuit are combined into a current sink type or By using a current discharge type double current duplication circuit, the current signal is duplicated as a double current signal, and the duplicated current signal is further duplicated by a current suction type or current discharge type double current duplication circuit. Then, by sequentially doubling, the reference current signal is generated as 2 times, 4 times, 8 times, and 16 times, and the duplicated current signal is serially transmitted to the signal electrode drive circuit. By going to, it is possible to generate a highly accurate reference current, in order to correct the current signal corresponding to the input image data is obtained, the image is obtained a desired display device. In addition, it can be configured with a circuit with a small number of TFTs used, and by reducing the circuit area of the reference current generating circuit arranged in the peripheral area other than the display screen, the overall glass size can be reduced and the display device can be downsized. In addition, since the circuit area is reduced, the yield of the display panel is improved and the cost can be reduced.

  The present invention, as a reference current generating circuit, duplicates a plurality of reference current signals as a minimum unit from a current signal as a minimum reference by a current suction type or current discharge type current duplicating circuit to obtain a desired reference current signal. In this way, a plurality of current duplicating circuits are connected in parallel, and the generated reference current signal is connected to the digital signal-current signal conversion circuit of the electrode driving circuit.

  Further, according to the present invention, as a reference current generation circuit, a plurality of reference current signals as minimum units are duplicated from a current signal as a minimum reference by a current suction type or current discharge type current duplication circuit, and the duplicated current signals are A current sink type or current discharge type, which is a pair of current sink type or current discharge type, generates a current double the minimum reference current signal and generates each double current. A reference current generation circuit comprising a current sink type or current discharge type current replication circuit for holding a signal is provided, and a current signal output from the reference current generation circuit is converted into a digital signal-current signal of a signal electrode drive circuit It is characterized by being connected to a conversion circuit.

  Further, according to the present invention, as a reference current generation circuit, a plurality of reference current signals as minimum units are duplicated from a current signal as a minimum reference by a current suction type or current discharge type current duplication circuit, and the duplicated current signals are The current sink type or current discharge type, which is a pair of current sink type or current discharge type, duplicates the current double the current signal as the minimum reference, and each current sink type or current All the outputs of the discharge type current duplicating circuit are connected, and the output is connected to the digital signal-current signal converting circuit of the signal electrode driving circuit.

  In the reference current generating circuit formed of the polycrystalline Si thin film transistor, a plurality of double current reference current signals determined by a multiple of the minimum reference current signal can be generated with high accuracy, and the generated current is generated in the DCC unit of the data driving circuit. By supplying a reference current signal, the present invention can be applied to an active drive type display device that enables desired image display with respect to input image data.

1 is a block diagram showing an embodiment of a reference current generating circuit in an active drive type display device according to the present invention. (A) is a circuit diagram which shows an example of the current discharge type | mold current signal replication circuit which comprises the basic unit of the said reference current generation circuit, (b) is an example of the current discharge type | mold current signal replication circuit of (a). It is explanatory drawing which shows the model figure. It is a block diagram which shows one Embodiment of the other reference current generation circuit in the active drive type display apparatus which concerns on this invention. (A) is a figure which shows an example of the current sink type | mold current signal replication circuit which comprises the basic unit of the reference current generation circuit of FIG. 3, (b) is an example of the current sink type | mold current signal replication circuit of (a). It is explanatory drawing which shows a model figure. It is a block diagram which shows one Embodiment of the other reference current generation circuit in the active drive type display apparatus which concerns on this invention. FIG. 6 is a circuit diagram showing an example of an operation of a current discharge type current signal duplicating circuit constituting a basic unit of the reference current generating circuit of FIG. 5. FIG. 6 is an explanatory diagram showing an operation of the reference current generating circuit of FIG. 5. It is a block diagram which shows one Embodiment of the other reference current generation circuit in the active drive type display apparatus which concerns on this invention. It is a circuit diagram which shows an example of operation | movement of the current sink type | mold current signal replication circuit which comprises the basic unit of the reference current generation circuit of FIG. It is a block diagram which shows one Embodiment of the other reference current generation circuit in the active drive type display apparatus which concerns on this invention. FIG. 11 is a block diagram illustrating an operation of the reference current generation circuit of FIG. 10. It is a block diagram which shows one Embodiment of the other reference current generation circuit in the active drive type display apparatus which concerns on this invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram illustrating an active drive type organic EL display device including a current drive type data drive circuit for explaining both a conventional technique and the present invention. FIG. 14 is a circuit diagram showing details of a part of the current drive type data drive circuit shown in FIG. 13. FIG. 15 is a circuit diagram showing details of the 1-bit DCC circuit shown in FIG. 14. It is a circuit diagram which shows an example of the reference current generation circuit which is a prior art. It is a circuit diagram which shows the other reference current generation circuit which is a prior art.

Explanation of symbols

300 constant voltage circuit 301 operational amplifier circuit 302 N-channel transistor 303 reference resistor 309 minimum reference current generator circuit 400 reference current generator circuits 401 to 463 current signal replication circuit

Claims (25)

Provided with a digital signal-current signal conversion circuit for converting a digital image signal of n (n: natural number of 2 or more) bits into a current signal based on n types of reference current signals output from the reference current generation circuit, and driving a signal electrode In an active drive type display device that performs gradation display of each electro-optic element based on the converted current signal through a circuit,
A minimum reference current signal generation circuit for generating a minimum reference current signal;
A plurality of current discharge type current replication circuits connected to replicate the minimum reference current signal and output the n types of reference current signals;
At the same time, the minimum reference current signal is passed from the current discharge type current replication circuit to the minimum reference current signal generation circuit so that the minimum reference current signal does not flow from two or more current discharge type current replication circuits. And outputting the minimum reference current signal duplicated from the current discharge type current duplicating circuit to obtain the n kinds of reference current signals. The current discharge type current replication circuit is:
A sample and hold unit for sampling and holding the minimum reference current signal;
The active drive type display device according to claim 1, further comprising: an output unit that discharges the sampled and held minimum reference current signal. Each of the sample and hold units includes first or third TFTs of P or N channel,
The first, second, and third TFTs sample the minimum reference current signal, the third TFT holds the sampled minimum reference current signal through a capacitor,
3. The active drive type display device according to claim 2, wherein the output unit includes third and fourth TFTs of P or N channel, and discharges the sampled and held minimum reference current signal. Provided with a digital signal-current signal conversion circuit for converting a digital image signal of n (n: natural number of 2 or more) bits into a current signal based on n types of reference current signals output from the reference current generation circuit, and driving a signal electrode In an active drive type display device that performs gradation display of each electro-optic element based on the converted current signal through a circuit,
A minimum reference current signal generation circuit for generating a minimum reference current signal;
A plurality of current sink type current replication circuits connected to replicate the minimum reference current signal and to absorb the n types of reference current signals;
At the same time, the minimum reference current signal generation circuit passes the minimum reference current signal to the current sink current replication circuit so that two or more current sink current replication circuits do not absorb the minimum reference current signal. An active drive type display device wherein the minimum reference current signal replicated to the current sink type current replication circuit is sucked to obtain the n kinds of reference current signals. The current sink type current replication circuit is:
A sample and hold unit for sampling and holding the minimum reference current signal;
The active drive type display device according to claim 4, further comprising an output unit configured to suck in the sampled and held minimum reference current signal. Each of the sample and hold units includes first or third TFTs of P or N channel,
The first, second, and third TFTs sample the minimum reference current signal, the third TFT holds the sampled minimum reference current signal through a capacitor,
6. The active drive type display device according to claim 5, wherein the output unit includes third and fourth TFTs of P or N channel, and sucks the sampled and held minimum reference current signal. Provided with a digital signal-current signal conversion circuit for converting a digital image signal of n (n: natural number of 2 or more) bits into a current signal based on n types of reference current signals output from the reference current generation circuit, and driving a signal electrode In an active drive type display device that performs gradation display of each electro-optic element based on the converted current signal through a circuit,
A minimum reference current signal generation circuit for generating a minimum reference current signal;
Two first current duplicating circuits, each of which is connected to output the n kinds of reference current signals and is composed of a current discharge type current duplicating circuit for duplicating the minimum reference current signal, and a pair of series connected in series A plurality of second current replication circuits comprising a current sink type current replication circuit and a current discharge type current replication circuit;
The output terminal of the first current replication circuit and the input terminal of the second current replication circuit are connected to each other, and the second current replication circuit other than for outputting the n types of reference current signals has an output terminal and an input terminal. Are connected to each other,
At the same time, the minimum reference current signal flows from the first current replication circuit to the minimum reference current signal generation circuit so that the minimum reference current signals do not flow from the two first current replication circuits. An active drive type display device that outputs the n kinds of reference current signals from a current duplicating circuit. Provided with a digital signal-current signal conversion circuit for converting a digital image signal of n (n: natural number of 2 or more) bits into a current signal based on n types of reference current signals output from the reference current generation circuit, and driving a signal electrode In an active drive type display device that performs gradation display of each electro-optic element based on the converted current signal through a circuit,
A minimum reference current signal generation circuit for generating a minimum reference current signal;
Two first current duplicating circuits, each of which is connected to output the n kinds of reference current signals and is composed of a current sink type current duplicating circuit for duplicating the minimum reference current signal, and a pair of currents connected in series A plurality of second current replication circuits comprising a discharge type current replication circuit and a current sink type current replication circuit;
The output terminal of the first current replication circuit and the input terminal of the second current replication circuit are connected to each other, and the second current replication circuit other than for outputting the n types of reference current signals has an output terminal and an input terminal. Are connected to each other,
At the same time, the minimum reference current signal is supplied from the minimum reference current signal generation circuit to the first current replication circuit so that the minimum reference current signal does not flow to the two first current replication circuits. An active drive type display device, wherein a current duplicating circuit sucks the n kinds of reference current signals. The current discharge type current replication circuit of the first current replication circuit is:
A first sample and hold unit that samples and holds the minimum reference current signal;
A first output unit for discharging the sampled and held minimum reference current signal to the output terminal,
The current sink type current replication circuit of the second current replication circuit is:
A second sample and hold unit for sampling and holding the current signal flowing through the input terminal;
The current discharge type current replication circuit of the second current replication circuit is:
A third sample and hold unit for sampling and holding the current signal held by the second sample and hold unit;
The active drive type display device according to claim 7, further comprising a third output unit that discharges the sampled and held current signal to the output terminal. The current sink type current replication circuit of the first current replication circuit is:
A first sample and hold unit that samples and holds the minimum reference current signal;
A first output section for sucking the sampled and held minimum reference current signal into the output terminal,
The current discharge type current replication circuit of the second current replication circuit is:
A second sample and hold unit for sampling and holding the current signal flowing through the input terminal;
The current sink type current replication circuit of the second current replication circuit is:
A third sample and hold unit that samples and holds the current signal held by the second sample and hold unit;
9. The active drive type display device according to claim 8, further comprising a third output unit that sucks the sampled and held current signal from the output terminal. The first sample and hold unit includes first or third TFTs of P or N channel,
The first, second, and third TFTs sample the minimum reference current signal, the third TFT holds the sampled minimum reference current signal via a first capacitor,
The first output unit includes third and fourth TFTs of P or N channel, and discharges the sampled and held minimum reference current signal.
Each of the second sample and hold units includes P or N channel fifth to seventh TFTs,
The fifth, sixth, and seventh TFTs sample a current signal flowing through the input terminal, and the seventh TFT holds the sampled current signal via a second capacitor,
The third sample and hold unit is composed of 8th to 10th TFTs of P or N channel,
The eighth, ninth and tenth TFTs sample the current signal held through the second capacitor, the tenth TFT holds the sampled current signal through the third capacitor,
10. The active drive type display device according to claim 9, wherein the third output unit includes tenth and eleventh TFTs of P or N channel, and discharges the sampled and held current signal to the output terminal. 11. . The first sample and hold unit includes first or third TFTs of P or N channel,
The first, second, and third TFTs sample the minimum reference current signal, the third TFT holds the sampled minimum reference current signal via a first capacitor,
The first output unit includes third and fourth TFTs of P or N channel and sucks the sampled and held minimum reference current signal.
Each of the second sample and hold units includes P or N channel fifth to seventh TFTs,
The fifth, sixth, and seventh TFTs sample a current signal flowing through the input terminal, and the seventh TFT holds the sampled current signal via a second capacitor,
The third sample and hold unit is composed of 8th to 10th TFTs of P or N channel,
The eighth, ninth and tenth TFTs sample the current signal held through the second capacitor, the tenth TFT holds the sampled current signal through the third capacitor,
11. The active drive type display device according to claim 10, wherein the third output unit includes tenth and eleventh TFTs of P or N channel, and sucks the sampled and held current signal from the output terminal. Provided with a digital signal-current signal conversion circuit for converting a digital image signal of n (n: natural number of 2 or more) bits into a current signal based on n types of reference current signals output from the reference current generation circuit, and driving a signal electrode In an active drive type display device that performs gradation display of each electro-optic element based on the converted current signal through a circuit,
A minimum reference current signal generation circuit for generating a minimum reference current signal;
Two first current duplicating circuits, each of which is connected to output the n kinds of reference current signals and is composed of a current discharge type current duplicating circuit for duplicating the minimum reference current signal, and a pair of series connected in series A plurality of second current replication circuits comprising a current sink type current replication circuit and a current discharge type current replication circuit;
The output terminal of the first current replication circuit and the input terminal of the second current replication circuit are connected to each other, and the output terminal and the input terminal of the second current replication circuit are connected to each other,
At the same time, the minimum reference current signal is sent from the first current replication circuit to the minimum reference current signal generation circuit so that the minimum reference current signals do not flow from the two first current replication circuits. An active drive type display device that outputs the n kinds of reference current signals from a current duplicating circuit. Provided with a digital signal-current signal conversion circuit for converting a digital image signal of n (n: natural number of 2 or more) bits into a current signal based on n types of reference current signals output from the reference current generation circuit, and driving a signal electrode In an active drive type display device that performs gradation display of each electro-optic element based on the converted current signal through a circuit,
A minimum reference current signal generation circuit for generating a minimum reference current signal;
Two first current duplicating circuits, each of which is connected to output the n kinds of reference current signals and is composed of a current sink type current duplicating circuit for duplicating the minimum reference current signal, and a pair of currents connected in series A plurality of second current replication circuits comprising a discharge type current replication circuit and a current sink type current replication circuit;
The output terminal of the first current replication circuit and the input terminal of the second current replication circuit are connected to each other, and the output terminal and the input terminal of the second current replication circuit are connected to each other,
At the same time, the minimum reference current signal is supplied from the minimum reference current signal generation circuit to the first current replication circuit so that the minimum reference current signal does not flow to the two first current replication circuits. An active drive type display device, wherein a current duplicating circuit sucks the n kinds of reference current signals. The current sink type current replication circuit of the first current replication circuit is:
A first sample and hold unit that samples and holds the minimum reference current signal;
A first output section for sucking the sampled and held minimum reference current signal into the output terminal,
The current discharge type current replication circuit of the second current replication circuit is:
A second sample and hold unit for sampling and holding the current signal flowing through the input terminal;
The current sink type current replication circuit of the second current replication circuit is:
A third sample and hold unit for sampling and holding a current signal flowing in the output unit of the current discharge type current replication circuit;
The active drive type display device according to claim 14, further comprising a third output unit that sucks the sampled and held current signal from the output terminal. The current discharge type current replication circuit of the first current replication circuit is:
A first sample and hold unit that samples and holds the minimum reference current signal;
A first output unit for discharging the sampled and held minimum reference current signal to the output terminal,
The current sink type current replication circuit of the second current replication circuit is:
A second sample and hold unit for sampling and holding the current signal flowing through the input terminal;
The current discharge type current replication circuit of the second current replication circuit is:
A third sample and hold unit for sampling and holding a current signal flowing through the output unit of the current sink type current replication circuit;
The active drive type display device according to claim 13, further comprising a third output unit that discharges the sampled and held current signal from the output terminal. The first sample and hold unit includes first or third TFTs of P or N channel,
The first, second, and third TFTs sample the minimum reference current signal, the third TFT holds the sampled minimum reference current signal via a first capacitor,
The first output unit includes third and fourth TFTs of P or N channel and sucks the sampled and held minimum reference current signal.
Each of the second sample and hold units includes P or N channel fifth to seventh TFTs,
The fifth, sixth, and seventh TFTs sample a current signal flowing through the input terminal, and the seventh TFT holds the sampled current signal via a second capacitor,
The third sample and hold unit is composed of 8th to 10th TFTs of P or N channel,
The eighth, ninth and tenth TFTs sample the current signal held through the second capacitor, the tenth TFT holds the sampled current signal through the third capacitor,
16. The active drive type display device according to claim 15, wherein the third output unit includes P and N channel tenth and eleventh TFTs, and sucks the sampled and held current signal from the output terminal. The first sample and hold unit includes first or third TFTs of P or N channel,
The first, second, and third TFTs sample the minimum reference current signal, the third TFT holds the sampled minimum reference current signal via a first capacitor,
The first output unit includes third and fourth TFTs of P or N channel, and discharges the sampled and held minimum reference current signal.
Each of the second sample and hold units includes P or N channel fifth to seventh TFTs,
The fifth, sixth, and seventh TFTs sample a current signal flowing through the input terminal, and the seventh TFT holds the sampled current signal via a second capacitor,
The third sample and hold unit is composed of 8th to 10th TFTs of P or N channel,
The eighth, ninth and tenth TFTs sample the current signal held through the second capacitor, the tenth TFT holds the sampled current signal through the third capacitor,
17. The active drive type display device according to claim 16, wherein the third output unit comprises P and N channel tenth and eleventh TFTs, and discharges the sampled and held current signal to the output terminal. .   A scanning electrode arranged in a row and a signal electrode arranged in a column, and an electro-optic element, a plurality of thin film transistors and a capacitor are arranged in each pixel region where the scanning electrode and the signal electrode intersect to drive the scanning electrode. By having a scanning electrode driving circuit, a signal electrode driving circuit for driving the signal electrode, and a reference current generating circuit, a desired current signal is written in a current duplicating circuit provided in the pixel region, and the current flowing to the electro-optical element is controlled. In an active drive type display device for gradation display, a plurality of current discharge type current duplicating circuits are connected in parallel with a current discharge type current duplicating circuit for duplicating a current signal as a minimum reference as desired. A current discharge type reference current generating circuit that generates a reference current signal and can generate a plurality of reference current signals is provided. Digital signal - active drive type display apparatus characterized by connecting to a current signal conversion circuit.   A scanning electrode arranged in a row and a signal electrode arranged in a column, and an electro-optic element, a plurality of thin film transistors and a capacitor are arranged in each pixel region where the scanning electrode and the signal electrode intersect to drive the scanning electrode. By having a scanning electrode driving circuit, a signal electrode driving circuit for driving the signal electrode, and a reference current generating circuit, a desired current signal is written in a current duplicating circuit provided in the pixel region, and the current flowing to the electro-optical element is controlled. In an active drive type display device for gray scale display, a desired reference current is obtained by connecting a plurality of current sink type current duplicating circuits in parallel with a current sink type current duplicating circuit duplicating a current signal as a minimum reference as a minimum unit. A current suction type reference current generation circuit capable of generating a signal and generating a plurality of reference current signals is provided. Digital signal - active drive type display apparatus characterized by connecting to a current signal conversion circuit.   A scanning electrode arranged in a row and a signal electrode arranged in a column, and an electro-optic element, a plurality of thin film transistors and a capacitor are arranged in each pixel region where the scanning electrode and the signal electrode intersect to drive the scanning electrode. By having a scanning electrode driving circuit, a signal electrode driving circuit for driving the signal electrode, and a reference current generating circuit, a desired current signal is written in a current duplicating circuit provided in the pixel region, and the current flowing to the electro-optical element is controlled. In an active drive display device for gradation display, a plurality of current discharge type current duplication circuits that duplicate the current signal that is the minimum reference, and a current suction type current duplication circuit and a current discharge type current duplication circuit are paired To generate a current signal that is twice the minimum reference current signal by using a plurality of current discharge type current duplicating circuits and hold each generated current signal Current discharge type current replica circuit includes a reference current generation circuit which is composed of, the reference current signal digital signal of the signal electrode driving circuit - active drive type, characterized in that connected to the current signal converting circuit display device.   A scanning electrode arranged in a row and a signal electrode arranged in a column, and an electro-optic element, a plurality of thin film transistors and a capacitor are arranged in each pixel region where the scanning electrode and the signal electrode intersect to drive the scanning electrode. By having a scanning electrode driving circuit, a signal electrode driving circuit for driving the signal electrode, and a reference current generating circuit, a desired current signal is written in a current duplicating circuit provided in the pixel region, and the current flowing to the electro-optical element is controlled. In an active drive display device for gradation display, a plurality of current sink type current duplicating circuits that duplicate the current signal that is the minimum reference, and a current discharge type current duplicating circuit and a current sink type current duplicating circuit are configured as a pair. To generate a current signal that is twice the minimum reference current signal using multiple current sink-type current replication circuits, and to hold each generated current signal Current sink-type current replica circuit includes a reference current generation circuit which is composed of, the reference current signal digital signal of the signal electrode driving circuit - active drive type, characterized in that connected to the current signal converting circuit display device.   A scanning electrode arranged in a row and a signal electrode arranged in a column, and an electro-optic element, a plurality of thin film transistors and a capacitor are arranged in each pixel region where the scanning electrode and the signal electrode intersect to drive the scanning electrode. By having a scanning electrode driving circuit, a signal electrode driving circuit for driving the signal electrode, and a reference current generating circuit, a desired current signal is written in a current duplicating circuit provided in the pixel region, and the current flowing to the electro-optical element is controlled In an active drive display device for gradation display, a plurality of current discharge type current duplication circuits that duplicate the current signal that is the minimum reference, and a current suction type current duplication circuit and a current discharge type current duplication circuit are paired Multiple current discharge type current duplication circuits replicate the current that is twice the minimum reference current signal, and connect all the current discharge type current duplication circuit outputs. , The output digital signal of the signal electrode driving circuit - active drive type display apparatus characterized by connecting to a current signal conversion circuit.   A scanning electrode arranged in a row and a signal electrode arranged in a column, and an electro-optic element, a plurality of thin film transistors and a capacitor are arranged in each pixel region where the scanning electrode and the signal electrode intersect to drive the scanning electrode. By having a scanning electrode driving circuit, a signal electrode driving circuit for driving the signal electrode, and a reference current generating circuit, a desired current signal is written in a current duplicating circuit provided in the pixel region, and the current flowing to the electro-optical element is controlled In an active drive display device for gradation display, a plurality of current sink type current duplicating circuits that duplicate the current signal that is the minimum reference, and a current discharge type current duplicating circuit and a current sink type current duplicating circuit are configured as a pair. Multiple current sink type current duplication circuits duplicate the current that is twice the minimum reference current signal and connect all the current sink type current duplication circuit outputs. , The output digital signal of the signal electrode driving circuit - active drive type display apparatus characterized by connecting to a current signal conversion circuit.   The active drive display device according to claim 1, wherein the electro-optical element is an organic EL element.

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