JP4877413B2 - Display device and portable terminal using the same - Google Patents

Description

  The present invention relates to a display device and a portable terminal using the display device, and more particularly to a display device such as a liquid crystal display (LCD) or an electroluminescence (EL) display and a portable terminal using the display device as a display unit. About.

  In recent years, thin and low power consumption panel displays have been widely used as display devices such as television receivers, computers, and portable terminals. As this panel display, on a transparent insulating substrate (panel) such as a glass substrate, a large number of pixels using TFT (thin film transistor) as a switching element, for example, are arranged in a matrix, and liquid crystal, electroluminescence, etc. An active matrix display device combined with a substance having an electro-optic effect is known.

As this active matrix display device, conventionally, for example, at least a part of peripheral circuits formed on a substrate for driving a pixel portion is made to be a complementary type similar to an active element connected to a pixel. There is known a liquid crystal display device composed of the above TFT and the remaining peripheral circuit composed of a semiconductor chip (for example, see Patent Document 1).

JP-A-4-242724

  In the case of this prior art, as shown in FIG. 12, a liquid crystal is interposed between a transparent insulating substrate 102 on which a part of the peripheral circuit 101 is formed and a transparent insulating substrate (counter substrate) 103 disposed opposite thereto. In the liquid crystal display device having the layer 104, a peripheral circuit constituted by a semiconductor chip, that is, an IC chip 105 is attached to a surface of the transparent insulating substrate 102 opposite to the peripheral circuit 101, and the peripheral circuit is formed using a flexible cable 106. A configuration for establishing electrical connection with the circuit 101 is adopted.

  However, when such a configuration is adopted, as apparent from FIG. 12, the thickness tb of the entire liquid crystal display device is increased by the thickness ta (for example, about 1 mm) of the IC chip 105 and the flexible cable 106. Therefore, the thickness of a device using the liquid crystal display device as a display unit is also increased. In particular, in a mobile terminal, for example, a mobile phone, the device main body is being thinned. If the thickness tb of a liquid crystal display device used as a display unit of the mobile phone is thick, the thinning of the phone main body is hindered. .

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a display device capable of reducing the thickness of the entire device and a portable terminal using the display device.

  A display device according to the present invention includes a first substrate on which a pixel portion in which a plurality of pixels are arranged in a matrix and a drive system that drives the pixel portion to write pixel signals are formed. A display device comprising: a second substrate disposed opposite to a substrate at a predetermined interval; and a material layer having an electro-optic effect held between the first and second substrates, the drive system And a control system that is formed on the first substrate with a semiconductor chip. And this display apparatus is used as the display part in portable terminals, such as a mobile telephone.

  In the display device having the above-described configuration and a mobile terminal using the display device, a control system for controlling the drive system is formed on the substrate on which the drive system is formed using a semiconductor chip, so that the thickness of the entire display device is the semiconductor chip. It does not depend on the thickness of Therefore, it is possible to reduce the thickness of the entire display device, and thus to reduce the thickness of a portable terminal using the display device as a display unit.

  According to the present invention, the thickness of the entire display device depends on the thickness of the semiconductor chip by forming the control system for controlling the drive system with the semiconductor chip on the substrate on which the drive system is formed. Therefore, it is possible to reduce the thickness of the entire display device, and thus to reduce the thickness of a portable terminal using the display device as a display portion.

1 is a schematic configuration diagram illustrating a configuration example of a liquid crystal display device according to an embodiment of the present invention, and illustrates a case where the present invention is applied to an analog dot sequential drive type active matrix liquid crystal display device. It is a block diagram showing an example of a configuration of a vertical driver in an analog dot sequential drive type active matrix type liquid crystal display device. FIG. 6 is a block diagram illustrating an example of a configuration of a horizontal driver in an analog dot sequential drive type active matrix liquid crystal display device. It is sectional drawing which shows the cross-sectional structure of a polysilicon TFT, (a) has shown the case of the bottom gate structure, (b) has shown the case of the top gate structure, respectively. It is a cross-sectional view of the liquid crystal display device which concerns on one Embodiment of this invention. It is sectional drawing which shows the structure of the electrical connection part of the circuit part and IC chip on a transparent insulating substrate. 1 is a schematic configuration diagram illustrating a configuration example of an active matrix liquid crystal display device of a time-division driving method to which the present invention is applied. FIG. 11 is a block diagram illustrating an example of a configuration of a horizontal driver in a time division drive type active matrix liquid crystal display device. It is a circuit diagram which shows an example of a structure of a time division switch part. It is a schematic block diagram which shows the application example of this invention. It is an external view which shows the outline of a structure of the mobile telephone which concerns on this invention. It is a cross-sectional view which shows the liquid crystal display device which concerns on a prior art example.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a configuration example of a liquid crystal display device according to an embodiment of the present invention, and shows a case where the present invention is applied to an analog dot sequential drive type active matrix liquid crystal display device.

  1, the active matrix type liquid crystal display device according to the present embodiment sequentially selects a pixel unit (effective pixel region) 12 in which a large number of pixels 11 are arranged in a matrix and each pixel 11 of the pixel unit 12 in units of rows. The vertical driver 13, the horizontal driver 14 that writes pixel signals to each pixel 11 selected in units of rows, and the control system 15 that controls these drivers 13 and 14 are mounted on the LCD panel 16.

  The LCD panel 16 includes two transparent insulating substrates (for example, glass substrates). In the pixel unit 12, m rows of gate lines (vertical selection lines) 17-1 to 17-m are formed on one substrate. A structure in which n columns of signal lines (source lines) 18-1 to 18-n are wired in a matrix, and a liquid crystal layer is held between the other substrates opposed to each other with a predetermined interval It has become. The pixels 11 are arranged at the intersections of the gate lines 17-1 to 17-m and the signal lines 18-1 to 18-n.

  Each of the pixels 11 includes a polysilicon TFT 19 which is a pixel transistor having a gate electrode connected to the gate lines 17-1 to 17-m and a source electrode connected to the signal lines 18-1 to 18-n. The liquid crystal cell (liquid crystal capacitor) 20 has a pixel electrode connected to the drain electrode, and the auxiliary capacitor 21 has one electrode connected to the drain electrode of the TFT 19.

  In this pixel structure, the liquid crystal cell 20 means a capacitance generated between a pixel electrode formed by the TFT 19 and a counter electrode formed corresponding thereto. The counter electrode of the liquid crystal cell 20 is connected to the common line 22 together with the other electrode of the auxiliary capacitor 21. A predetermined DC voltage is applied to the common line 22 as a common voltage VCOM.

  Here, as a driving method of the liquid crystal cell 20, for example, a so-called common inversion driving method in which the common voltage VCOM is inverted every 1H (one horizontal period) is employed. By using this common inversion driving method, the polarity of the common voltage VCOM is inverted every 1H. Therefore, the power supply voltage of the horizontal driver 14 for writing a pixel signal to each pixel 11 can be reduced, and the power consumption of the entire device It is possible to contribute to the reduction.

  For example, as shown in FIG. 2, the vertical driver 13 includes a shift register 31, a level shifter 32, and a gate buffer 33. When the vertical start pulse VST is input, the shift register 31 sequentially outputs the vertical start pulse VST as a shift pulse from each transfer stage by sequentially transferring the vertical start pulse VST in synchronization with the vertical clock VCK.

  The level shifter 32 boosts the shift pulse output from each transfer stage of the shift register 31 and supplies it to the gate buffer 33. The gate buffer 33 sequentially applies the shift pulse boosted by the level shifter 32 to the gate lines 17-1 to 17-m of the pixel unit 12 as a vertical scanning pulse, and selectively drives each pixel 11 of the pixel unit 12 in units of rows. Thus, vertical scanning is performed.

  For example, as shown in FIG. 3, the horizontal drive 14 includes a shift register 34, a level shifter, a data latch circuit 36, a D / A converter 37, and a buffer 38. When the horizontal start pulse HST is input, the shift register 34 sequentially outputs the horizontal start pulse HST as a shift pulse from each transfer stage by sequentially transferring the horizontal start pulse HST in synchronization with the horizontal clock HCK to perform horizontal scanning.

  The level shifter 35 boosts the shift pulse output from each transfer stage of the shift register 34 and supplies it to the data latch circuit 36. The data latch circuit 36 sequentially latches digital image data data of predetermined bits inputted in response to a shift pulse supplied from the shift register 34 through the level shifter 35. The D / A converter 37 has, for example, a reference voltage selection type configuration, converts the digital image data latched by the data latch circuit 36 into an analog image signal, and passes through the buffer 38 to the signal lines 18-1 to 18- of the pixel unit 12. Give to n.

  In FIG. 1 again, the control system 15 that controls the vertical driver 13 and the horizontal driver 14 includes a timing controller (TC) 23, a reference voltage generation source 24, a DC-DC converter 25, and the like. The vertical driver 13 and the horizontal driver 14 are mounted on the same substrate, that is, the LCD panel 16.

  In the control system 15, the timing controller 23 receives, for example, a power supply voltage VDD from an external power supply unit (not shown), digital image data data from an external CPU (not shown), and an external clock generator (not shown). A clock CLK is input from a TCP (tape carrier package) (not shown).

  In this example, a CPU, a memory for storing image data, or a clock generator is provided outside the LCD panel 16, but at least one of them is mounted on the LCD panel 16 as a part of the control system 15. It is also possible.

  While controlling the timing, the timing controller 23 sends a clock signal such as the vertical start pulse VST and the vertical clock VCK and various control signals to the vertical driver 13, a clock signal such as the horizontal start pulse HST and the horizontal clock HCK, and various control signals. And the digital image data data are supplied to the horizontal driver 14, respectively.

  The reference voltage generation source 24 generates a plurality of reference voltages having different voltage values, and supplies the plurality of reference voltages to the reference voltage selection type D / A converter 37 of the horizontal driver 14 as the reference voltages. The DC-DC converter 25 converts a low direct current voltage (low voltage) into two or more kinds of high direct current voltages (high voltage), and each circuit unit such as the vertical driver 13, the horizontal driver 14, and the reference voltage generation source 24. To give.

  In the active matrix type liquid crystal display device of the dot sequential driving system configured as described above, the transistors constituting the vertical driver 13 and the horizontal driver 14 are the same as those of the pixel unit 12 by TFTs, particularly the same polysilicon TFT as the pixel transistor of the pixel unit 12. The liquid crystal layer is formed on the transparent insulating substrate and in the region sealed with the seal member. In this case, due to the mobility of polysilicon, the operating range of the driving frequency of the vertical driver 13 and the horizontal driver 14 is limited to 10 MHz or less.

  The polysilicon TFT used as the pixel transistor of the pixel section 12 and the transistor constituting the drive system has a bottom gate structure in which the gate electrode is disposed below the oxide film, and the gate electrode is disposed on the oxide film. There is a thing of the top gate structure made. The cross-sectional structures of these polysilicon TFTs are shown in FIGS.

4A, a gate electrode 42 is formed on a glass substrate 41, and a polysilicon (Poly-Si) layer 44 is formed thereon via a gate oxide film 43, Further thereon, an interlayer insulating film 45 is formed. A source region 46 and a drain region 47 made of an N ⁺ diffusion layer are formed on the gate insulating film 43 on the side of the gate electrode 42, and a source electrode 48 and a drain electrode 49 are respectively formed in these regions 46 and 47. It is connected.

In the TFT having the top gate structure shown in FIG. 4B, a polysilicon layer 52 is formed on a glass substrate 51, a gate electrode 54 is formed thereon via a gate oxide film 53, and an interlayer is further formed thereon. An insulating film 55 is formed. A source region 56 and a drain region 57 made of an N ⁺ diffusion layer are formed on the glass substrate 51 on the side of the polysilicon layer 52. A source electrode 58 and a drain electrode 59 are formed in these regions 56 and 57, respectively. It is connected.

  On the other hand, the timing controller 23, the reference voltage generation source 24, and the DC-DC converter 25 of the control system 15 are integrated into an IC using single crystal silicon. The silicon IC is mounted on the same plane as the vertical driver 13 and the horizontal driver 14, that is, on a substrate (transparent insulating substrate) on which the drivers 13 and 14 are formed by, for example, a COG (chip on glass) method. A silicon IC formed of this single crystal silicon can be driven even at 100 MHz.

  As described above, a circuit portion having a large characteristic variation by low-speed driving, that is, by using the polysilicon TFT for the vertical driver 13 and the horizontal driver 14, the circuit portion by the polysilicon TFT is the pixel portion in terms of reliability. Since the structure is sealed in 12 sealed spaces, there is no mixing of Na + ions or the like that cause the Vth (threshold voltage) shift of the TFT. At this time, in terms of the thickness of the liquid crystal display device, the TFT is negligibly thin as compared with the liquid crystal cell (liquid crystal layer), and thus does not increase the thickness of the liquid crystal display device itself.

  On the other hand, a circuit portion that is driven at high speed or a circuit portion that has small variation in characteristics, that is, the timing controller 23 of the control system 15, the reference voltage generation source 24, and the DC-DC converter 25 are integrated with single crystal silicon, and the vertical driver 13 and the horizontal driver A configuration in which the driver 14 is arranged on the same substrate is adopted. FIG. 5 shows a cross section of the liquid crystal display device in this case.

  In FIG. 5, as described above, the liquid crystal layer 63 is held between the transparent insulating substrate 61 on which the vertical driver 13 and the like are formed and the transparent insulating substrate (counter substrate) 62 disposed to face the transparent insulating substrate 61, and is sealed. In the liquid crystal display device that is sealed with the member 64, an IC chip 65 obtained by converting the control system 15 into an IC is mounted on the transparent insulating substrate 61 on which the vertical driver 13 and the like are formed by the COG method.

  FIG. 6 shows a structure of an electrical connection portion between the circuit portion on the transparent insulating substrate 61 and the IC chip 65. In FIG. 6, the IC chip 65 has a circuit portion 652 formed on a silicon substrate 651, and the circuit portion 652 is electrically connected to an external connection terminal (bump material) 653. Then, the external connection terminal 653 is electrically connected to the circuit wiring on the transparent insulating substrate 61, for example, the aluminum wiring 611 through the anisotropic conductive film 66. Note that an interlayer insulating film 67 is interposed between the transparent insulating substrate 61 and the IC chip 65.

  As described above, when the IC chip 65 is mounted on the transparent insulating substrate 61, the IC chip 65 itself is not problematic in terms of reliability because the protective layer is formed on the silicon IC during IC fabrication. . In addition, since it is a COG structure, it is necessary to perform reliability reinforcement | strengthening with respect to the metal material of a connection part with a transparent insulated substrate. For this purpose, after forming the IC chip 65 on the transparent insulating substrate 61, a protective layer made of silicon resin may be formed so as to surround the IC chip 65 and the substrate 61.

  In the mounting structure, the IC chip 65 is formed such that the thickness t1 (about 0.7 mm) is equal to or less than the total thickness t3 of the transparent insulating substrate 62 and the seal member 64 on the opposite side. Thus, the thickness (thickness) t2 of the entire liquid crystal display device does not depend on the thickness t1 of the IC chip 65, so that the liquid crystal display device can be thinned. That is, the total thickness t2 of the transparent insulating substrate 61, the transparent insulating substrate 62, and the seal member 64 is the thickness of the liquid crystal display device itself.

  Further, by forming the peripheral circuit as an IC and mounting the IC chip 65 on the transparent insulating substrate 61, the number of places that are electrically connected to the external circuit of the LCD panel 16 can be reduced. The reliability against vibration and the like can be improved, and the occurrence of poor electrical connection in the manufacturing process is reduced.

  By the way, when the module is mounted, the mechanical strength of the IC chip 65 mounted by the COG method tends to be weaker than the adhesive strength of the portion of the pixel portion 12 forming the liquid crystal cell. On the other hand, by setting the thickness t1 of the IC chip 65 to be equal to or less than the total thickness t3 of the transparent insulating substrate 62 and the sealing member 64, and preferably thinner than the thickness t3. In contrast, a structure in which a force is hardly applied from the outside can be obtained.

In the liquid crystal display device according to the present embodiment, in addition to reducing the thickness of the device itself, in order to reduce the weight of the device itself, PET (polyethylene telephtalete) is used as a substrate material for the transparent insulating substrates 61 and 62. ) Or PES (poly ether sulfone).

  The following four cases can be considered as combinations of substrate materials for the transparent insulating substrates 61 and 62. In Case 1, silicon oxide is used as the substrate material for the transparent insulating substrates 61 and 62. In case 2, silicon oxide is used as the substrate material of the transparent insulating substrate 61, and an organic material such as PET or PES is used as the substrate material of the transparent insulating substrate 62. In case 3, an organic material such as PET or PES is used as the substrate material for the transparent insulating substrates 61 and 62. In case 4, an organic material such as PET or PES is used as the substrate material of the transparent insulating substrate 61, and silicon oxide is used as the substrate material of the transparent insulating substrate 62.

  Of the combinations of the substrate materials of case 1 to case 4, the organic material such as PET or PES is used as the combination of case 3, i.e., the transparent insulating substrates 61 and 62, and the material is very lightweight. Therefore, it is most advantageous in reducing the thickness and weight of the liquid crystal display device itself.

  In the above embodiment, the case where the present invention is applied to an analog dot sequential drive active matrix liquid crystal display device has been described. However, the present invention is not limited to this, and a so-called time-division drive method (selector method) described below. The present invention can also be applied to the active matrix liquid crystal display device.

  FIG. 7 is a schematic configuration diagram showing a configuration example of a time-division drive type active matrix liquid crystal display device to which the present invention is applied.

  In FIG. 7, a time division drive type active matrix liquid crystal display device includes a pixel unit 72 in which a large number of pixels 71 are arranged in a matrix, a vertical driver 73 that sequentially selects each pixel 71 of the pixel unit 72 in units of rows, A horizontal driver 74 that writes a pixel signal to each pixel 71 selected in units of rows, a time-division switch unit 75 for time-division driving, and a control system 76 that controls the vertical and horizontal drivers 73 and 74 and the time-division switch unit 75. It is configured to be mounted on the LCD panel 77.

  Each of the pixels 71 includes a polysilicon TFT 80 having a gate electrode connected to the gate lines 78-1 to 78-m and a source electrode connected to the signal lines 79-1 to 79-n, and a drain electrode of the TFT 80. The liquid crystal cell 81 is connected to an electrode, and the auxiliary capacitor 82 is connected to one of the drain electrodes of the TFT 20. In each of the pixels 71 having such a configuration, the counter electrode of the liquid crystal cell 81 is connected to the common line 83 together with the other electrode of the auxiliary capacitor 82. A predetermined DC voltage is applied to the common line 83 as a common voltage VCOM.

  Here, the time division driving method will be described. In the time division driving method, a plurality of adjacent signal lines of the pixel unit 72 are divided as one unit (block), and signal voltages applied to the plurality of signal lines in the one divided block are time-sequentially horizontal drivered. A time-division switch unit 75 is provided with a plurality of signal lines as a unit while outputting from each output terminal 74, and the time-series signal voltage output from the horizontal driver 74 by the time-division switch unit 75 is time-divisionally divided. This is a driving method for sampling and sequentially supplying a plurality of signal lines.

  In order to realize this time-division driving, the horizontal driver 74 has a configuration in which a plurality of signal lines are set as one unit, and signal voltages applied to the plurality of signal lines are output in time series. An example of the configuration of the horizontal driver 74 is shown in FIG.

  As is apparent from FIG. 8, the horizontal driver 74 includes a shift register 84, a sampling switch group 85, a level shifter 86, a data latch circuit 87, and a D / A converter 88. In this example, for example, 5-bit digital image data The data 1 to data 5 and the power supply voltages Vdd and Vss are fetched from both sides in the shift direction of the shift register 84.

  In the horizontal driver 74 configured as described above, when the horizontal start pulse HST is input, the shift register 84 sequentially outputs the horizontal start pulse HST as a shift pulse from each transfer stage by sequentially transferring the horizontal start pulse HST in synchronization with the horizontal clock HCK. Then, horizontal scanning is performed. Each of the sampling switches in the sampling switch group 85 sequentially samples the input digital image data data1 to data5 in response to shift pulses (sampling pulses) sequentially output from the shift register 84.

  The level shifter 86 boosts, for example, 5 V digital data sampled by the sampling switch group 85 to liquid crystal drive voltage digital data. The data latch circuit 87 is a memory that accumulates digital data boosted by the level shifter 86 for 1H. The D / A converter 88 has a reference voltage selection type configuration, for example, and converts 1H digital image data output from the data latch circuit 87 into an analog image signal and outputs the analog image signal.

  A so-called column inversion driving method is used as the horizontal driver 74. In order to realize column inversion driving, the horizontal driver 74 outputs a signal voltage whose potential is inverted every odd number and even number of each output terminal, and inverts the polarity of the signal voltage for each field. Here, the column inversion driving method is a driving method in which pixels adjacent in the vertical direction have the same polarity and the state of the pixel polarity is inverted for each field. The horizontal driver 74 can also support 1H common (VCOM) inversion driving.

  On the other hand, the time division switch unit 75 includes an analog switch (transmission switch) that samples the time-series signal voltage output from the horizontal driver 74 in a time division manner. A specific configuration example of the time division switch unit 75 is shown in FIG. Note that one time division switch unit 75 is provided for each output of the horizontal driver 74. Here, a case where three-time division driving is performed corresponding to R (red), G (green), and B (blue) is shown as an example.

  The time-division switch unit 75 includes CMOS analog switches 75-1, 75-2, 75-3 in which PchMOS transistors and NchMOS transistors are connected in parallel. In this example, the analog switches 75-1, 75-2, 75-3 are CMOS switches, but it is also possible to use PMOS or NMOS switches.

  In this time division switch section 75, the input terminals of the three analog switches 75-1, 75-2, 75-3 are connected in common, and the output terminals are connected to the three signal lines 79-1, 79-2. , 79-3 are connected to the respective one ends. Signal potentials output in time series from the horizontal driver 74 are applied to the input terminals of the analog switches 75-1, 75-2, and 75-3.

Further, a total of six control lines 89-1 to 89-6 are wired, two for each analog switch. Two control input terminals (that is, gates of the CMOS transistors) of the analog switch 75-1 are connected to the control lines 89-1 and 89-2, and two control input terminals of the analog switch 75-2 are connected to the control line 89-. Two control input terminals of the analog switch 75-3 are connected to control lines 89-5 and 89-6, respectively.

  Gate selection signals S1 to S3 and XS1 to XS3 for sequentially selecting the three analog switches 75-1, 75-2, and 75-3 with respect to the six control lines 89-1 to 89-6, It is given from a timing controller (TC) 90 (see FIG. 7) described later. However, the gate selection signals XS1 to XS3 are inverted signals of the gate selection signals S1 to S3.

  The gate selection signals S1 to S3, XS1 to XS3 sequentially turn on the three analog switches 75-1, 75-2, and 75-3 in synchronization with the time-series signal potential output from the horizontal driver 74. As a result, the analog switches 75-1, 75-2, and 75-3 sample the time-series signal potential output from the horizontal driver 74 in three time divisions in the 1H period, and corresponding signal lines 79-1. , 79-2 and 79-3, respectively.

  In FIG. 7 again, the control system 76 that controls the vertical driver 73, the horizontal driver 74, and the time division switch unit 75 includes a timing controller (TC) 90, a reference voltage generation source 91, a DC-DC converter 92, and the like. The circuit is mounted on the same substrate as the pixel unit 72, that is, on the LCD panel 77 together with the vertical driver 73, the horizontal driver 74, and the time division switch unit 75.

  In the control system 76, the timing controller 90 receives, for example, a power supply voltage VDD from an external power supply unit (not shown), digital image data data from an external CPU (not shown), and an external clock generator (not shown). Clock CLK is input from TCP (not shown) from not shown.

  In this example, a CPU, a memory for storing image data, or a clock generator is provided outside the LCD panel 77. However, at least one of them is a part of the control system 76, and this control system 76 is configured as a single unit. Crystal silicon IC (COG) can be formed and mounted on the LCD panel 77.

  In addition to the CPU, the memory, or the clock generator, the LCD light source control circuit, the LCD (EL) display graphic controller, and the display device are used, for example, as a display unit of a mobile phone as described later. Various control circuits such as a transceiver circuit and a battery control circuit can be formed as a single crystal silicon IC as a part of the control system 76 and mounted on the LCD panel 77.

  Here, the LCD light source control circuit is a circuit that controls the backlight or front light of the LCD, and does not supply power to the light source (light emitting diode, fluorescent display tube) during standby of the mobile phone, It has a function to supply power during input operation. A graphic controller for LCD (EL) display is a circuit that converts image data supplied from a transceiver circuit into an image format that can be displayed in the image area of the LCD and EL. Convert to display format.

  The transceiver circuit is a circuit for communication, receives a digital signal or an analog signal that arrives by electromagnetic waves, converts it into a digital signal or an analog signal, and outputs it. When the battery control circuit is not in use, the CPU, LCE (EL) panel, and graphic controller clocks are automatically operated at a low speed after a certain period of time to reduce power consumption. When used as a display unit of a mobile phone, the CPU also has a function of converting input information at the time of button operation on the mobile phone into digital data.

  While controlling the timing, the timing controller 90 sends the clock signal such as the vertical start pulse VST and the vertical clock VCK and various control signals to the vertical driver 73, the clock signal such as the horizontal start pulse HST and the horizontal clock HCK, and various control signals. The digital image data data is supplied to the horizontal driver 74, and the gate selection signals S1 to S3 and XS1 to XS3 are supplied to the time division switch unit 75, respectively.

  The reference voltage generation source 91 generates a plurality of reference voltages having different voltage values, and supplies the plurality of reference voltages to the reference voltage selection type D / A converter 87 of the horizontal driver 74 as the reference voltages. The DC-DC converter 92 converts a low direct current voltage (low voltage) into two or more kinds of high direct current voltages (high voltage), and each circuit unit such as a vertical driver 73, a horizontal driver 74, a reference voltage generation source 91, and the like. To give.

  In the time-division drive type active matrix liquid crystal display device having the above configuration, the vertical driver 73, the transistors constituting the horizontal driver 74, and the analog switches constituting the time-division switch unit 75 are TFTs, particularly the pixels of the pixel unit 72. The same polysilicon TFT as the transistor is formed on the same transparent insulating substrate as the pixel portion 72 and in the region where the liquid crystal layer is sealed by the sealing member.

  On the other hand, the timing controller 90, the reference voltage generation source 91, and the DC-DC converter 92 of the control system 76 are made into an IC using single crystal silicon. The silicon IC is formed on the same plane as the vertical driver 73 and the horizontal driver 74, that is, on the substrate on which the drivers 73 and 74 are formed, for example, by the COG method.

  As described above, the circuit portion having a large variation in characteristics due to low-speed driving, that is, the vertical driver 73, the horizontal driver 74, and the time division switch unit 75 are configured using polysilicon TFTs. The small circuit portion, that is, the timing controller 90 of the control system 76, the reference voltage generation source 91, and the DC-DC converter 92 are integrated with single crystal silicon and arranged on the same substrate as the vertical driver 73 and the horizontal driver 74. As a result, it is possible to obtain the same effects as those of the above-described embodiment.

  In the present embodiment, the timing controller 90, the reference voltage generation source 91, and the DC-DC converter 92 are mounted on the vertical driver 72 side. However, as shown in FIG. 10, the timing controller 90, the reference voltage generation source 91, and The DC-DC converter 92 can be integrated with the horizontal driver 73 into a single crystal silicon IC (COG), and the IC 98 can be mounted on the LCD panel 77.

  According to this, the area for the area occupied by the timing controller 90, the reference voltage generation source 91 and the DC-DC converter 92 becomes unnecessary beside the vertical driver 72, and the LCD panel 77 corresponding to the occupied area becomes unnecessary. Since the horizontal frame width can be reduced, it is useful when applied to a display device having a specification in which the horizontal frame is desired to be narrowed.

  At this time, in addition to the timing controller 90, the reference voltage generation source 91, and the DC-DC converter 92, as described above, the CPU, the memory or the clock generator, the LCD light source control circuit, and the LCD (EL) display Of course, at least one of various control circuits such as a graphic controller, a telephone transceiver circuit, and a battery control circuit may be integrated with the horizontal driver 73 into a single crystal silicon IC.

  In each of the above embodiments, the case where the present invention is applied to an active matrix liquid crystal display device using liquid crystal as a substance having an electro-optic effect has been described as an example. However, an EL display device using electroluminescence (EL) is described. The present invention can be similarly applied to other active matrix display devices.

  The display device according to the present invention is used as a display for OA devices such as personal computers and word processors and television receivers, and in particular, mobile phones and PDAs (personal digital assistants) whose device main body is being made thinner. ) Etc. are suitable for use as a display unit of a portable terminal.

  FIG. 11 is an external view schematically showing the configuration of a mobile terminal to which the present invention is applied, for example, a mobile phone.

  The mobile phone according to the present example has a configuration in which a speaker unit 94, a display unit 95, an operation unit 96, and a microphone unit 97 are arranged in this order from the upper side on the front side of the device casing 93. In the mobile phone having such a configuration, for example, a liquid crystal display device is used as the display unit 95, and the liquid crystal display device according to the present invention described above is used as the liquid crystal display device.

  As described above, in a mobile terminal such as a mobile phone, the liquid crystal display device according to the present invention is used as the display unit 95, so that the liquid crystal display device can be thinned. There is an advantage that it can greatly contribute to the thinning of the apparatus main body.

  11, 71 pixel, 12, 72 pixel unit, 13, 73 vertical driver, 14, 74 horizontal driver, 15, 76 control system, 16, 77 LCD panel, 19, 80 polysilicon TFT, 20 81, liquid crystal cell, 23, 90, timing controller, 24, 91, reference voltage source, 25, 92, DC-DC converter

Claims (9)

A pixel portion in which a plurality of pixels are arranged in a matrix;
A driving system for driving the pixel portion to write a pixel signal;
A control system for controlling the drive system;
With
The drive system has a horizontal driver including a reference voltage selection type D / A converter,
The control system includes a DC-DC converter that converts a first DC voltage into a second DC voltage, and the second DC voltage supplied from the DC-DC converter, and outputs a plurality of reference voltages having different voltage values. A reference voltage generation source that generates and serves as a reference voltage for the D / A converter;
The control system is composed of a semiconductor chip integrally with the horizontal driver,
The display device, wherein the semiconductor chip is mounted on the same substrate as the substrate on which the pixel portion is formed. The display device according to claim 1, wherein the horizontal driver supplies an analog image signal output from the D / A converter via an external connection terminal of the semiconductor chip to a signal line wired to the pixel unit. . The drive system further includes a vertical driver;
The vertical driver is supplied with the second DC voltage from the DC-DC converter to perform vertical scanning,
The horizontal driver is supplied with the second DC voltage from the DC-DC converter, is supplied with the reference voltage from the reference voltage generation source, and writes an image signal in a row selected by the vertical driver. Or the display apparatus of Claim 2. The control system further includes a timing controller in the semiconductor chip,
The horizontal driver operates based on a horizontal start pulse and a horizontal clock signal generated by the timing controller,
The display device according to claim 3, wherein the vertical driver operates based on a vertical start pulse and a vertical clock signal generated by the timing controller . The drive system is, in any one of claims 1 to 4 comprising means for sampling the image signal voltage sequence in a time division time outputted from the horizontal driver through the external connection terminals of the semiconductor chip The display device described. A transistor constituting a pixel transistor of the pixel portion is a thin film transistor,
The thin film transistor is made of polysilicon,
The display device according to claim 1, wherein the semiconductor chip is made of single crystal silicon . The display device according to claim 1, wherein the semiconductor chip is mounted by a COG method . The display device according to claim 1, wherein at least one of the first substrate and the second substrate is made of silicon oxide or an organic material . A pixel portion in which a plurality of pixels are arranged in a matrix;
A driving system for driving the pixel portion to write a pixel signal;
A control system for controlling the drive system;
With
The drive system has a horizontal driver including a reference voltage selection type D / A converter,
The control system includes a DC-DC converter that converts a first DC voltage into a second DC voltage, and the second DC voltage supplied from the DC-DC converter, and outputs a plurality of reference voltages having different voltage values. A reference voltage generation source that generates and serves as a reference voltage for the D / A converter;
The control system is composed of a semiconductor chip integrally with the horizontal driver,
The semiconductor chip is mounted on the same substrate on which the pixel portion is formed.
A display device was used as a display unit
Mobile device.

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