JP4896446B2 - Display device, driving method thereof, and electronic apparatus - Google Patents

Description

The present invention relates to a passive matrix display device. In particular, the present invention relates to a passive matrix display device using a light emitting element such as an organic electroluminescent element in a pixel portion.

  In recent years, so-called self-luminous display devices in which pixels are formed by light-emitting elements such as light-emitting diodes (LEDs) have attracted attention. Organic light emitting diodes (also referred to as organic light emitting diodes (OLEDs), organic EL elements, and electro luminescence (EL) elements) attract attention as light emitting elements used in such self-luminous display devices. It has been used for organic EL displays and the like.

  Since light-emitting elements such as OLEDs are self-luminous, there are advantages such as higher pixel visibility than a liquid crystal display, no need for a backlight, and high response speed. The luminance of the light emitting element is controlled by the value of current flowing therethrough.

  In a display device using such a self-luminous light emitting element, a simple matrix (passive) method and an active matrix method are known as driving methods. The active matrix system includes a control circuit having several switching thin film transistors (also referred to as TFTs) in each pixel, and the light emission / non-light emission of each pixel is controlled by the control circuit of each pixel. On the other hand, in a simple matrix display device, a plurality of column signal lines and a plurality of row signal lines are arranged so as to intersect each other, and an organic EL element is sandwiched between the intersections. Therefore, a potential difference is generated in a region sandwiched between the selected row signal line and the column signal line that performs output, and an organic EL element (referred to as a pixel) emits light when a current flows.

A light-emitting element has a property that its resistance value (internal resistance value) changes depending on ambient temperature (hereinafter referred to as environmental temperature). Specifically, when the room temperature is a normal temperature, the resistance value decreases when the temperature is higher than normal, and the resistance value increases when the temperature is lower than normal. Therefore, in constant voltage driving, the current value increases to a higher brightness than the desired brightness when the temperature increases, and the current value decreases to a brightness lower than the desired brightness when the temperature decreases. Further, the light emitting element has a property that its current value decreases with time.

Due to the properties of the light-emitting element as described above, when the environmental temperature changes or changes with time occur, the luminance varies. In view of the above circumstances, it is an object of the present invention to provide a constant voltage drive display device that suppresses an influence caused by a change in a current value of a light emitting element due to a change in environmental temperature and a change over time.

The structure of the present invention includes a column signal line, a row signal line, a light emitting element in which a layer containing an organic compound is formed between the column signal line and the row signal line, a first electrode, and a second electrode. A monitor element formed in a region sandwiched between electrodes, a current source, and an amplifier;
A first electrode of the monitor element and the current source are connected;
A first electrode of the monitor element and an input terminal of the amplifier are connected;
In the display device, an output of the amplifier is input to the column signal line.

In another structure, a column signal line, a row signal line, a light emitting element in which a layer containing an organic compound is formed between the column signal line and the row signal line, a first electrode, A plurality of monitor elements formed in a region sandwiched between two electrodes, a current source, and an amplifier;
A first electrode of each of the plurality of monitor elements and the current source are connected;
A first electrode of each of the plurality of monitor elements and an input terminal of the amplifier are connected;
In the display device, an output of the amplifier is input to the column signal line.

In another configuration, the column signal line, the row signal line, a light emitting element in which a layer containing an organic compound is formed between the column signal line and the row signal line, the first electrode, A monitor element formed in a region sandwiched between row signal lines, a current source, and an amplifier;
A first electrode of the monitor element and the current source are connected;
A first electrode of the monitor element and an input terminal of the amplifier are connected;
In the display device, an output of the amplifier is input to the column signal line.

In another configuration, the column signal line, the row signal line, a light emitting element in which a layer containing an organic compound is formed between the column signal line and the row signal line, the first electrode, A plurality of monitor elements formed in a region sandwiched between row signal lines, a current source, and an amplifier,
A first electrode of each of the plurality of monitor elements and the current source are connected;
A first electrode of each of the plurality of monitor elements and an input terminal of the amplifier are connected;
In the display device, an output of the amplifier is input to the column signal line.

Another configuration includes a column signal line, a row signal line, a light emitting element sandwiched between the column signal line and the row signal line, a monitor element, and a current source that supplies a constant current to the monitor element. ,
The monitor element is driven by a constant current from a current source,
This is a display device that detects a voltage applied between both electrodes of the monitor element and inputs it to the light emitting element.

Another configuration includes a column signal line, a row signal line, a light emitting element sandwiched between the column signal line and the row signal line, a monitor element, and a current source that supplies a constant current to the monitor element. ,
The monitor element is driven by a constant current from a current source,
The potential of the column signal line is a display device that is set by detecting the potential on the anode side of the monitor element.

In addition, another configuration includes a column signal line, a row signal line, a light emitting element sandwiched between the column signal line and the row signal line, a monitor element, a current source that supplies a constant current to the monitor element, an amplifier, With
The monitor element is driven by a constant current from a current source,
This is a display device in which the potential on the anode side of the monitor element is detected by an amplifier, and the detected potential is set to a column signal line.

In addition, other configurations include a column signal line, a row signal line, a light emitting element sandwiched between the column signal line and the row signal line, a monitor element, a current source for supplying a constant current to the monitor element, and a monitor element A capacitive element that holds a voltage between the two electrodes; a first switch that turns on and off the connection between the capacitive element and the current source; a second switch that turns on and off the connection between the current source and the monitor element; and an amplifier;
The monitor element is driven by a constant current from a current source,
The display device is characterized in that the potential on the anode side of the monitor element is detected by an amplifier, and the detected potential is set to a column signal line.

Another structure is a display device in which the monitor element is formed over the same substrate as the light-emitting element in the above structure.

An electronic apparatus including the display device having the above structure in a display portion.

In addition, the present invention uses a display device including a column signal line, a row signal line, a light emitting element sandwiched between the column signal line and the row signal line, and a monitor element.
The monitor element is driven by a constant current,
Detects the voltage applied between the monitor element poles,
This is a method for driving a display device in which a detected voltage is set in a light emitting element.

Another configuration includes a column signal line, a row signal line, a light emitting element sandwiched between the column signal line and the row signal line, a monitor element, and a current source that supplies a constant current to the monitor element. Using the device,
The monitor element is driven by a constant current from a current source,
Detect the potential on the anode side of the monitor element,
This is a method for driving a display device in which a detected potential is set in a light emitting element.

In another configuration, a column signal line, a row signal line, a light emitting element sandwiched between the column signal line and the row signal line, a monitor element, a current source for supplying a constant current to the monitor element, and an amplifier are provided. Using a display device with
The monitor element is driven by a constant current from a current source,
This is a display device driving method in which the potential on the anode side of the monitor element is detected by an amplifier, and the detected potential is set in a column signal line.

In addition, other configurations include a column signal line, a row signal line, a light emitting element sandwiched between the column signal line and the row signal line, a monitor element, a current source for supplying a constant current to the monitor element, and a monitor element A display device including a capacitive element that holds a voltage between both electrodes, a first switch that turns on and off the connection between the capacitive element and the current source, a second switch that turns on and off the connection between the current source and the monitor element, and an amplifier Using,
When the first switch and the second switch are on, the monitor element is driven by a constant current from a current source,
Detect the potential on the anode side of the monitor element with an amplifier, set the detected potential to the column signal line,
When the first switch and the second switch are turned off, the capacitance element holds the potential on the anode side of the monitoring element at the moment of turning off,
This is a driving method of a display device in which a potential held by a capacitor element is detected by an amplifier, and the detected potential is set to a column signal line.

In the above structure, the display device driving method is such that the period during which current flows through the monitor element is 30% of the period during which the display device performs display.

In the above-described configuration, the period during which the current flows through the monitor element is g (Q _p ) / g (Q _m ) = exp [(k · t) β] (g (Q _p ) is the total charge amount Q of the light emitting element. monotonically decreasing function of the _p parameters, g (Q _m) is monotonically decreasing function of a parameter the total charge Q _m of the monitoring element, k is the rate constant, beta is set so as to satisfy the parameters) representing the initial degradation A display device driving method.

In the above structure, the first switch and the second switch are driving methods of the display device formed by transistors having different polarities.

In the above structure, the first switch and the second switch are driving methods of the display device formed by transistors having the same polarity.

In another structure, a column signal line, a row signal line, a light emitting element in which a layer containing an organic compound is formed between the column signal line and the row signal line, a first electrode, A monitor element formed in a region sandwiched between two electrodes, a first current source, a second current source, and an amplifier;
In the precharge period, a current is supplied from the first current source to the monitor element,
The potential of the first electrode of the monitor element is input to the input terminal of the amplifier,
From the output terminal of the amplifier, a potential approximately equal to the potential of the first electrode of the monitor element is output to the column signal line,
In the light emission period, the display device is driven by supplying current from the second current source to the monitor element to emit light.

In another structure, a column signal line, a row signal line, a light emitting element in which a layer containing an organic compound is formed between the column signal line and the row signal line, a first electrode, A monitor element formed in a region sandwiched between two electrodes, a current source, and an amplifier;
In the precharge period, current is supplied from the current source to the monitor element,
The potential of the first electrode of the monitor element is input to the input terminal of the amplifier,
From the output terminal of the amplifier, a potential approximately equal to the potential of the first electrode of the monitor element is output to the column signal line,
In the light emission period, the display device is driven by supplying current from the current source to the monitor element to emit light.

Variations in luminance due to changes in the current value of the light-emitting element due to changes in environmental temperature and changes over time can be suppressed.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention can be implemented in many different modes, and those skilled in the art can easily understand that the modes and details can be variously changed without departing from the spirit and scope of the present invention. Is done. Therefore, the present invention is not construed as being limited to the description of this embodiment mode.

The basic principle of temperature and deterioration compensation according to the present invention will be described with reference to FIG. FIG. 1 is a schematic view of a display device having a circuit for compensating for temperature and deterioration.

The display device of the present invention includes a column signal line driver circuit 101, a row signal line driver circuit 102, a pixel portion 103, an amplifier 104, a constant current source 105, and a monitor element 107. The pixel portion 103 includes a plurality of light emitting elements 108. Note that the monitor element 107 is formed using a light-emitting element having the same voltage-current characteristics as the light-emitting element 108. For example, in the case where a light-emitting element is formed using an EL element, the EL element of the monitor element 107 and the EL element of the light-emitting element 108 are manufactured using the same EL material under the same conditions. Moreover, it is desirable to form integrally on the same board | substrate. The display device of the present invention has a temperature and deterioration compensation function (hereinafter, simply referred to as a compensation function means a temperature and deterioration compensation function).

The constant current source 105 supplies a constant current to the monitor element 107. That is, the monitor element 107 is driven at a constant current. Therefore, the current value of the monitor element 107 is always constant. When the environmental temperature changes in this state, the resistance value of the monitor element 107 itself changes. When the resistance value of the monitor element 107 changes, the current value of the monitor element 107 is constant, so that the potential difference between both electrodes of the monitor element 107 changes. By detecting the potential difference of the monitor element 107 due to this temperature change, a change in the environmental temperature is detected. More specifically, since the potential of the electrode on the side of the monitor element 107 maintained at a constant potential, that is, the potential of the cathode in FIG. 1, does not change, the potential on the side connected to the current source 105, that is, in FIG. A change in potential on the anode 106 side is detected.

Here, the temperature dependence of the voltage / current characteristics of the monitor element 107 will be described with reference to FIG. The voltage / current characteristics of the monitor element 107 at room temperature, low temperature, and high temperature are shown by lines 1001, 1002, and 1003, respectively. When the current value flowing from the constant current source 105 to the monitor element 107 is I ₀ , the voltage of V ₀ is applied to the monitor element at room temperature. At a low temperature, the voltage is V ₁ , and at a high temperature, the voltage is V ₂ . That is, when a current having a current value I ₀ flows through the monitor element at room temperature, the voltage drop becomes V ₀ , the voltage drop becomes V _{1 in the} low temperature monitor element, and the voltage drop becomes V _{2 in the} high temperature monitor element.

Information including such a change in the voltage of the monitor element 107 is supplied to the amplifier 104, and the potential supplied to the light emitting element 108 by the amplifier 104 is set based on the potential of the anode 106. That is, as shown in FIG. 10, the potential is set so that the voltage V ₁ is applied to the light emitting element 108 when the environmental temperature is low, and the voltage V ₂ is applied to the light emitting element 108 when the temperature is high. Set the potential as follows. Then, the power supply potential input to the light emitting element 108 can be corrected according to the temperature change. That is, the fluctuation of the current value caused by the temperature change can be suppressed.

FIG. 11 is a graph of voltage / current characteristics for explaining the deterioration of the monitor element 107 with time. The initial characteristic of the monitor element 107 is represented by a line 1101, and the characteristic after degradation is represented by 1102. Note that the initial characteristics and the characteristics after deterioration are measured under the same temperature conditions. When the current I ₀ flows through the monitor element 107 in the initial characteristic state, the voltage applied to the monitor element 107 becomes V ₃ , and the voltage applied to the monitor element 107 after deterioration becomes V ₄ . Therefore, if this voltage V ₄ is applied to the light emitting element 108 that has deteriorated in the same manner, the apparent deterioration of the light emitting element 108 can be reduced. As described above, when the monitor element 107 deteriorates together with the light emitting element 108, the deterioration of the light emitting element 108 can be compensated.

As described above, a voltage follower circuit using an operational amplifier can be applied to the amplifier 104 that sets the same potential to the anode of the light emitting element 108 in accordance with the change in the potential of the anode 106 of the monitor element 107. Since the non-inverting input terminal of the voltage follower circuit has a high input impedance and the output terminal has a low output impedance, the input terminal and the output terminal have the same potential, and the current of the constant current source 105 does not flow into the voltage follower circuit. This is because a current can be supplied from. Therefore, it goes without saying that the circuit having such a function is not limited to the voltage follower circuit.

Thus, the potential of the anode of the light emitting element 108 is set and output to the column signal lines S1 to Sn. A bias is applied to the pixels in the region where the selected row signal lines V1 to Vm (referring to the row signal lines connected to GND in FIG. 1) and the column signal lines S1 to Sn are crossed. When the light flows, the light emitting element 108 emits light. Note that the unselected row signal line means that the current is not supplied to the light emitting element 108 (or does not emit light) by being connected to the terminal having the potential of VDD.

Here, a gradation display method of the light emitting element will be described. FIG. 13 shows a timing chart of an example for obtaining a 3-bit gradation of the time gradation method. A period obtained by dividing one frame period by the number of pixels in the vertical direction is substantially one horizontal line period. In the case of performing display with 3 bits, that is, 8 gradations, a period for outputting a potential to the column signal lines S1 to Sn may be set in proportion to the gradation as shown in FIG.

In the active matrix method, the light emitting element of each pixel can be turned on almost during one frame period. However, as described above, in the passive matrix time-graded line sequential driving method, each pixel is operated during one frame period. Since the period during which the light emitting elements are turned on cannot be set to be longer than one horizontal line period, it is necessary to instantaneously increase the luminance of each pixel. For example, in an active matrix system having the same number of pixels, a value obtained by multiplying the brightness necessary for each pixel by the number of pixels in the vertical direction is the instantaneous brightness necessary for each pixel in the passive matrix system. Thus, in order to obtain a large luminance instantaneously, power consumption also increases. In addition, when a large current flows instantaneously in order to increase the luminance of each pixel, the deterioration of the light emitting element further proceeds.

Therefore, when constant current driving is employed in the passive matrix system, when a transistor operating in a saturation region is used as a current source, the source side potential needs to be set very high. This is because, as described above, it is necessary to instantaneously increase the luminance of the light-emitting element, which requires a large current and operates a transistor used as a current source in a saturation region. This is because it is necessary to set the potential. In addition, since a large current is passed in order to instantaneously increase the luminance, the light emitting element is rapidly deteriorated. Therefore, the applied voltage is required to flow the same current to the light emitting element due to the deterioration. Therefore, the potential on the source side of a transistor used as a current source must be set higher in advance.

However, according to the present invention, if the potential on the anode side of the light emitting element is determined, constant luminance driving can be performed without setting a high potential in advance as in constant current driving.
Although FIG. 1 shows a case where there is one monitor element 107, a plurality of monitor elements may be connected in parallel. For example, if X monitor elements are connected in parallel, the current value of the constant current source 105 may be increased by X times.

(Embodiment 1)
In this embodiment mode, a specific structure of the display device of the present invention will be described.

First, a column signal line driver circuit applicable to the display device of the present invention will be described. The column signal line driving circuit shown in FIG. 2 performs time gradation display by controlling the output period of the potential set by the temperature and deterioration compensation circuit (hereinafter simply referred to as compensation circuit) to the column signal lines S1 to Sn. be able to.

First, the constant current source 201 supplies a constant current to the monitor element 202. That is, the monitor element 202 performs constant current driving. Then, the potential on the anode 203 side of the monitor element is detected by the amplifier 204 and output to the column signal line. Although a voltage follower circuit is used as an amplifier in this embodiment, it is needless to say that the circuit is not limited to this as long as it has a similar function.

In addition, a pulse is output from the pulse output circuit 205, and a video signal (DATA) is sequentially input to the first latch circuit 206 in accordance with the pulse. The data held in the first latch circuit is input to the second latch circuit 207 at the timing of the latch pulse (SLAT) signal. Then, the data held in the second latch circuit 207 controls the ON period of the switches 208a1 to 208an, and sets the period during which the data is output to the column signal lines S1 to Sn, that is, the potential is supplied to the light emitting elements. In this way, time gradation display can be performed.

In practice, for example, in the case of performing 3-bit gradation, the first latch circuit 206 and the second latch circuit 207 have three latch circuits for each column signal line, and each column signal line has Hold 3-bit data. Then, the 3-bit data output from the second latch circuit is converted into a pulse width when gradation is performed with 8 gradations, and the switches 208a1 to 208an are turned on for the period of the pulse width. In this way, display with 8 gradations can be performed.

Next, an example in which the column signal line driver circuit of FIG. 2 is applied to a display device is shown in FIG. The configuration of FIG. 14 is a configuration in which the same number of monitor elements 1407a1 to 1407am as the number of row signal lines are arranged in parallel. The display device includes a row signal line driver circuit 1402, a column signal line driver circuit 1401, and a pixel portion 1403. The column signal line driver circuit 1401 includes a pulse output circuit 1408, a first latch circuit 1409, a second latch circuit 1410, and a switch 1411. In this structure, the second latch circuit 1410 can output data while inputting data to the first latch circuit 1409. Then, a signal is output from the row signal line driving circuit 1402, and one row signal line is selected from the row signal lines V1 to Vm. Then, the potential difference between the selected row signal line and the potential set to the column signal line is applied to the light emitting element 1412 sandwiched between the row signal line and the column signal line. When a current flows, the light emitting element 1412 is turned on. At this time, the magnitude of the potential set to the column signal line is set in the same manner for each column signal line, but the period in which the potential is supplied is different. In this way, time gradation display can be performed.

In the present invention, a constant current is passed from the current source 1405 to the monitor elements 1407a1 to 1407am connected in parallel. That is, constant current driving is performed. Then, the potentials of the anodes 1406 of these monitor elements 1407a1 to 1407am are detected, and the potential supplied to the column signal line is set by the voltage follower circuit 1404. Thus, a display device having a function of temperature and deterioration compensation can be provided.

A driving method having a temperature and deterioration compensation function and driving at a constant luminance is also referred to as constant brightness.

The number of monitor elements can be selected as appropriate. Of course, there may be one or a plurality as shown in FIG. When only one monitor element is used, the current value to be supplied to the constant current source 1405 may be set to a current value to be supplied to the light emitting element of each pixel, so that power consumption can be reduced.

Further, the configuration is not limited to the configuration of FIG. 14, and the monitor element may be disposed on the column signal line driver circuit side, or may be disposed on the opposite side of the row signal line driver circuit with the pixel portion interposed therebetween. It may be arranged on the opposite side of the column signal line across the section. In order to effectively exhibit the temperature compensation function, the arrangement of the monitor elements can be selected as appropriate.

In addition, the monitor element and the light emitting element are preferably formed using the same material at the same time on the same substrate. This is because the variation in current-voltage characteristics between the monitor element and the light emitting element can be reduced.

Note that when the potentials set to the column signal lines are common as in the configuration of FIG. 14, full color display is possible by combining a monochrome display device or a light emitting element that can emit white light and a color filter. It may be applied to a display device.

Further, the potential of the power supply line can be set for each pixel of RGB. An example is shown in FIG. The same reference numerals are used in common with FIG.

Here, column signal lines connected to pixels emitting R (red) are indicated by column signal lines Sr1 to Srn. Column signal lines connected to pixels emitting G (green) are indicated by column signal lines Sg1 to Sgn. Column signal lines connected to pixels emitting B (blue) light are indicated by column signal lines Sb1 to Sbn.

The operation of the column signal line in FIG. 9 will be briefly described. A pulse is output from the pulse output circuit 905, and a video signal (DATA) is sequentially input to the first latch circuit 906 according to the pulse. The data held in the first latch circuit 906 is input to the second latch circuit 907 at the timing of the latch pulse (SLAT) signal. The data held in the second latch circuit 907 controls the ON periods of the switches 908r1 to 908rn, 908g1 to 908gn, and 908b1 to 908bn, and the column signal lines Sr1 to Srn, the column signal lines Sg1 to Sgn, the column signal A period for outputting to the lines Sb1 to Sbn, that is, supplying a potential to the light emitting elements is set. In this way, time gradation display can be performed.

Here, the current source 901r supplies current to the monitor element 902r, and the voltage follower circuit 904r detects the potential of the anode 903r of the monitor element 902r, and sets this potential to the column signal lines Sr1 to Srn. The current source 901g supplies current to the monitor element 902g, and the voltage follower circuit 904g detects the potential of the anode 903g of the monitor element 902g, and sets this potential to the signal lines Sg1 to Sgn. The current source 901b supplies current to the monitor element 902b, and the voltage follower circuit 904b detects the potential of the anode 903b of the monitor element 902b, and sets this potential to the signal lines Sb1 to Sbn. Thus, since the potential can be set for each of RGB, a desired potential can be set for the light emitting element when the temperature characteristics and the deterioration characteristics differ depending on the EL material for each RGB. That is, the potential of the column signal line can be set and corrected for each RGB.

(Embodiment 2)
In the present embodiment, a configuration in which the accuracy of deterioration compensation is further improved will be described.

When the display device is continuously used for a long period of time, a difference occurs in the progress of deterioration between the monitor element and the light emitting element. This difference becomes larger as the use period is longer, and the function of deterioration compensation is lowered.

Here, the case where a difference arises in deterioration is demonstrated using FIG. The initial characteristics of the voltage / current characteristics of the monitor element 107 and the light emitting element 108 in FIG. 1 are represented by a line 1201, the characteristic after degradation of the monitor element 107 when the display device is used for a certain period is represented by a line 1202, and The characteristic is represented by a line 1203. Thus, there is a difference between the deterioration of the monitor element 107 and the progress of the deterioration of the light emitting element 108. This is because current always flows through the monitor element 107 when the display device performs display. However, since each light emitting element 108 of the pixel has a light emitting period and a non-light emitting period, an error occurs in the deterioration of the monitor element 107 and the light emitting element 108 over time. That is, the progress of the deterioration of the light emitting element is delayed as compared with the deterioration of the monitor element.

Here, in the initial characteristics of the monitor element 107 and the light emitting element 108, when a current having a current value I ₀ flows through the monitor element 107 and the light emitting element 108, a voltage of V ₅ is applied to the monitor element in the initial characteristic. The voltage V ₆ is applied after the light emitting element 108 is deteriorated, and the voltage V ₇ is applied after the monitor element 107 is deteriorated. In other words, it is necessary to apply a voltage of V ₆ in order to flow the current value I ₀ to the light emitting element 108 after deterioration, and V ₇ to flow the current value I ₀ to the monitor element 107 after deterioration. It is necessary to apply a voltage.

In this state, when the potential V ₇ of the anode 106 of the monitor element 107 is detected and this potential V ₇ is set to the light emitting element 108 by the amplifier 104, the voltage V ₆ necessary for flowing the current value I ₀ to the light emitting element. The above voltage is applied and power consumption increases. In addition, since the progress of deterioration of each light emitting element of the pixel is different, image sticking becomes conspicuous when a voltage higher than necessary is applied.

Therefore, in this embodiment, the deterioration of each light emitting element and the progress of the deterioration of the monitor element are made closer to improve the accuracy of deterioration compensation.

Therefore, in this embodiment mode, an average period of the light emission periods of the light emitting elements of the respective pixels of the display device is set as a period of current flowing through the monitor element. Preferably, a current flows through the monitor element during a period of 10% to 70% of a period during which the display device performs display.

Here, in the display device, the average value of the ratio between the light emitting period and the non-light emitting period of the light emitting element of each pixel is substantially a ratio of 3: 7. Therefore, more preferably, a current is supplied to the monitor element for 30% of the period during which the display device performs display.

FIG. 3 shows a configuration of a compensation circuit capable of setting the light emission period of the monitor element. The same reference numerals are used in common with FIG. A difference from the configuration of FIG. 2 is that a capacitor 301, a first switch 302, and a second switch 303 are provided.

When a constant current is passed through the monitor element 202, the first switch 302 and the second switch 303 are turned on. Then, a current flows through the monitor element 202, and the potential on the anode 203 side of the monitor element 202 is accumulated in the capacitor element 301. This potential is input to the non-inverting input terminal of the voltage follower circuit 204, and the same potential is applied to the output terminal. Is output. In this manner, a desired potential can be set for the light-emitting element whose voltage / current characteristics have changed due to a change in environmental temperature.

When the monitor element 202 does not emit light, the first switch 302 and the second switch 303 are turned off, and the potential on the anode 203 side of the monitor element 202 is held in the capacitor 301. At this time, the second switch 303 is turned off simultaneously with the first switch 302, or at least turned off first. This is because if the first switch 302 is turned off before the second switch 303, the potential of the capacitor in which the potential on the anode side of the monitor element 202 is accumulated fluctuates.

Thus, even in the non-light emitting period, the potential on the anode 203 side of the monitor element 202 at the moment when the second switch 303 is turned off is input to the non-inverting input terminal of the voltage follower circuit 204. Then, the same potential is output to the output terminal of the voltage follower circuit 204, and the current flowing in the monitor element 202 at the moment when the second switch 303 is turned off can be passed to the light emitting element.

In this configuration, the temperature compensation function can be achieved during the period when the current is passed through the monitor element, so that both deterioration compensation and temperature compensation can be realized. In the present embodiment, the deterioration compensation function is particularly excellent.

Here, as described above, in the time gradation display of the display device, the average value of the ratio of light emission to non-light emission of each pixel per frame period is substantially a ratio of 3: 7. Therefore, it can be seen that the ratio of the average amount of current flowing through the monitor element that continues to pass current and the amount of current flowing through each light emitting element during the display of the display device is 10: 3. Therefore, the progress of deterioration of the monitor element and the light emitting element of the pixel can be brought close to each other by setting the period for supplying current to the monitor element to 30% per one frame period. That is, the accuracy of deterioration compensation can be improved.

Further, in the above configuration, a monitor element for deterioration compensation is provided for each of RGB, and a deterioration compensation and temperature compensation function with further improved accuracy can be realized. When the degradation and life of EL are different for each RGB, or when the temperature dependency IV characteristics of the EL elements are different for each RGB, a monitor element corresponding to each RGB light emitting element is provided to compensate for temperature and degradation. It is good to do. Furthermore, the accuracy of further deterioration compensation is improved by setting the light emission period of the monitor element for each RGB in accordance with the average value (duty ratio) of the ratio of the light emission period and the non-light emission period of each RGB light emitting element. That is, since the average value of the progress of the deterioration of the monitor element and the progress of the deterioration of each light emitting element becomes substantially equal, the system for deterioration compensation becomes higher. Furthermore, since the same color EL material can be used for the monitor element, the accuracy of light-emitting element temperature compensation can be improved.

(Embodiment 3)
In the present embodiment, a configuration in which the accuracy of deterioration compensation is improved while maintaining the accuracy of temperature compensation will be described with reference to FIG.

The display device includes a current source 201, a monitor element 401a and a monitor element 401b, a voltage follower circuit 204, a switch 402a, and a switch 402b.

The operation of the compensation circuit having this configuration will be briefly described. The switches 402a or 402b are alternately turned on. Then, a current always flows through the monitor element 401a or the monitor element 401b. The potential of the anode (anode 403a or 403b) of either of these monitor elements can be detected by the voltage follower circuit 204, and the potential can be set to the column signal lines S1 to Sn. In addition, if the periods during which the switches 402a and 402b are turned on are set to be the same, deterioration over time of the monitor elements 401a and 401b can be delayed.

In addition, since current is always supplied to one of the monitor elements, the potential of the anode of the monitor element is detected, and the potential of the anode of the light emitting element is set, temperature compensation can always be performed.

An example of a switch that can be operated in this way is shown in FIG. Switch 501 performs the functions of switches 402a and 402b in FIG. The terminal a of the switch 501 is connected to the current source 201, the terminal b is connected to the anode 403a of the monitor element 401a, and the terminal c is connected to the anode 403b of the monitor element 401b. When the current from the current source 201 is supplied to the monitor element 401a, the terminal a and the terminal b of the switch 501 are in a conductive state, and when the current is supplied to the monitor element 401b, the terminal a and the terminal c are in a conductive state.

An example of a specific configuration of the switch 501 is shown in FIG. The switch 501 includes analog switches 601 and 602 and an inverter 603. A control signal is input to the control input terminals of the analog switch 601 and the analog switch 602, and either the analog switch 601 or the analog switch 602 is turned on. In this way, it is possible to select which of the monitor element 401a and the monitor element 401b the current is to flow.

Further, the functions of the switch 402a and the switch 402b can be realized using transistors as shown in FIG. A P-channel switching transistor 701 and an N-channel switching transistor 702 are used. The source terminal of the switching transistor 701 and the drain terminal of the switching transistor 702 are connected to the current source 201, the drain terminal of the switching transistor 701 is the anode 403a of the monitor element 401a, and the source terminal of the switching transistor 702 is the monitor. It is connected to the anode 403b of the element 401b. Control signals are input to the gate terminals of these transistors. Then, since the switching transistors 701 and 702 have different polarities, one of them is turned on. Thus, the monitor element 401a or 401b can be selected. Of course, this configuration may be a configuration in which a plurality of monitor elements are arranged as in the display device shown in FIG.

Note that the same function can be achieved by using transistors having the same polarity as shown in FIG. A control signal is input to the control input terminal of one switching transistor 801 as it is, and a control signal is input to the other switching transistor 802 via an inverter 803. Then, since the control signal is inverted and input to the switching transistor 802, one of the switching transistors can be turned on. Note that although FIG. 8 is described using N-channel transistors 801 and 802, the same function can be achieved by using only P-channel transistors. Of course, in this configuration, switching transistors 801 and 802 may be arranged as a set by the number of rows of the row signal lines as shown in FIG.

Note that the number of monitor elements to be selected is not limited to two, and a plurality of monitor elements can be arranged in parallel to further slow down the deterioration. Accordingly, the progress of deterioration of the light emitting element and the monitor element can be made closer by arranging the three monitor elements in parallel and sequentially selecting the monitor elements through which a current flows. By appropriately arranging and switching the number of monitor elements, the deterioration of the monitor element and the progress of the deterioration of the light emitting element can be brought close to each other.

As in the configuration of FIG. 19, when the cathodes of the monitor elements 1901a1 to 1901am are connected to the row signal lines V1 to Vm, the monitor elements are switched for each monitor element connected to the row signal lines. That is, only the monitor element connected to the selected row signal line (a row signal line in which a potential for causing a potential difference so that a current flows in the light emitting element by a signal potential from the column signal line) is set. Therefore, the duty ratio between the light emitting element and the monitor element can be made closer. Further, if a plurality of monitor elements are arranged, it is possible to average the variation in characteristics of each monitor element. As an example, FIG. 20 shows a configuration in which three monitor elements are connected in parallel to each of the row signal lines V1 to Vm. In the configuration of FIG. 20, the cathodes of monitor elements 2001a1 to 2001am, 2001b1 to 2001bm, and 2001c1 to 2001cm are connected to the row signal lines V1 to Vm, respectively. Therefore, the duty ratio of the light emitting element and the monitor element can be made closer, and the characteristics of the monitor element are averaged by the three connected in parallel. Note that the number of monitor elements that can be connected in parallel is not limited to three and can be appropriately arranged.

Further, as described with reference to FIG. 9, the configuration in which the potential is set for each of the RGB pixels can be applied to the configuration of FIG. Such a configuration is shown in FIG. The configuration of FIG. 15 sets the potential for each RGB, so that the monitor element group 1507r formed of the same material as the R light emitting element, the monitor element group 1507g formed of the same material as the G light emitting element, and B And a monitor element group 1507b formed of the same material as the light-emitting element. Each monitor element group has the same number of monitor elements as the number of row signal lines. The display device includes a row signal line driver circuit 1502, a column signal line driver circuit 1501, and a pixel portion 1503. The column signal line driver circuit 1501 includes a pulse output circuit 1508, a first latch circuit 1509, a second latch circuit 1510, and a switch 1511. The pixel portion 1503 includes an R light emitting element 1512r, a G light emitting element 1512g, and a B light emitting element 1512b. In this structure, the second latch circuit 1510 can output data while inputting data to the first latch circuit 1509. Then, a signal is output from the row signal line driving circuit 1502, and one row signal line is selected from the row signal lines V1 to Vm. Then, the potential difference between the selected row signal line and the potential set in the column signal line is applied to the light emitting element sandwiched between the row signal line and the column signal line. When the current flows, the light emitting element is turned on. At this time, the magnitude of the potential set to the column signal line can be made different for each RGB. Note that the potential of each column signal line for each RGB is set in the same way, but the period in which the potential is supplied is different. In this way, time gradation display can be performed.

The present invention applies a constant current from a current source 1505r to a monitor element group 1507r having a plurality of monitor elements connected in parallel, and sends a constant current from a current source 1505g to a monitor element group 1507g having a plurality of monitor elements connected in parallel. A constant current is passed from the current source 1505b to the monitor element group 1507b having a plurality of monitor elements connected in parallel. That is, constant current driving is performed. However, when the row signal line to which the monitor element is connected is selected (the potential for causing a potential difference to flow through the light emitting element is set in the row signal line by the signal potential from the column signal line. Current flows only in the monitor element when the monitor element group 1507r, the monitor element group 1507g, and the monitor element group 1507b. That is, each of the current sources 1505r, 1505g, and 1505b may set a current value for driving one monitor element at a constant current. The potential of the anode 1506r of the monitor element group 1507r is detected by the voltage follower circuit 1504r, the potential supplied to the column signal lines Sr1 to Srn is set, and the potential of the anode 1506g of the monitor element group 1507g is set by the voltage follower circuit 1504g. Is detected, the potential supplied to the column signal lines Sg1 to Sgn is set, the potential of the anode 1506b of the monitor element group 1507b is detected by the voltage follower circuit 1504b, and the potential supplied to the column signal lines Sb1 to Sbn is set. . Accordingly, since the monitor element can be switched every time the row signal line is switched, the duty ratio of each monitor element can be brought close to the duty ratio of the light emitting element, and the potential can be set for each of the RGB light emitting elements. Therefore, in consideration of the element characteristics for each RGB, a potential can be applied to the light emitting element. Therefore, a display device having a function of temperature and deterioration compensation can be provided.

(Embodiment 4)
In this embodiment mode, a method for correcting an error of deterioration with time due to the duty ratio between a monitor element and a light emitting element in a pixel will be described.

The current flowing through the organic thin film is called a trap charge limited current (TCLC) and is expressed by the following formula (1).
J = S · V ⁿ (1)
(J: current density, V: voltage, S: numerical value determined by the material and structure of the EL element, n: numerical value of 2 or more)
Then, when formula (1) is modified, formula (2) is obtained.
logJ = n · logV + logS (2)

Equation (2) can be represented by a straight line having an inclination n, and the smaller the logS, the more the straight line shifts to the high voltage side. Here, in an EL element having an element structure, initial IV characteristics (shown as initial characteristics in FIG. 16), IV characteristics after storage at room temperature for 1000 hr (shown after storage for 1000 hr in FIG. 16), at room temperature FIG. 16 shows IV characteristics (shown after 1000 hr drive in FIG. 16) after constant current driving at 1000 hr · initial luminance 1000 cd / m 2 (after the luminance is reduced by 30%). As can be seen from FIG. 16, it can be seen that not only after driving for 1000 hr, but also the IV characteristics after storage for 1000 hr without driving are shifted from the initial characteristics to the high voltage side.

Next, the initial state of the EL element, the state after being stored at room temperature for 1000 hr, the constant current driving at 1000 hr at room temperature and the initial luminance of 1000 cd / m ² (after the luminance is reduced by about 30%), and the n and S The change in value is shown in FIG. n is indicated by a line 401 and S is indicated by a line 402. As can be seen from FIG. 17, n decreases even when stored without passing a 1000 hr current, and the rate of decrease is almost the same as when driven by passing a 1000 hr current. That is, n is a parameter that decreases almost only with the passage of time, regardless of whether or not current is passed. That is, it can be expressed by the following formula (3).
n = f (t) (3)

On the other hand, S is a parameter that hardly changes when stored for 1000 hours, but decreases for the first time when a current is passed. Relying on the flow of current regardless of time can be said to be a function of the total charge Q that has flowed (ie, current × time = [C]). That is, it can be represented by the following formula (4).
S = g (Q) (4)

Since S decreases as a current flows, g (Q) is a monotonically decreasing function. Further, from the expressions (1), (3), and (4), the IV characteristic of the monitor element and the IV characteristic of the pixel can be expressed as the following expressions (5) and (6).
J ₀ = g (Q _m ) · V ^{f (t)} (5)
_{J p = g (Q p)} · V f (t) ··· (6)

J ₀ is the current density (= constant) of the monitor element, J _p is the current density of the pixel, Q _m is the total amount of charge flowing to the monitor element, Q _p is the total amount of charge flowing to the pixel, V is the voltage, and t is Represents time. Then, from the expressions (5) and (6), the current density J _p flowing through the pixel can be expressed by the following expression (7).
_{J p = J 0 · g (} Q p) / g (Q m) ···· (7)

Since g (Q) is a monotonically decreasing function, the duty ratio is different. When more charge is applied to the monitor element than the pixel, J _p is always greater than J ₀ . This equation (7) represents the rate of increase of the current density J _p of the pixel by the compensation function of the present invention. That is, it can be said that ideal constant luminance driving can be performed if J _p is increased according to a certain formula.

First, when the luminance of the pixel is L and the current efficiency is η, it can be expressed as in Expression (8).
L = η · J _p (8)

Further, assuming that the initial luminance is L ₀ and the initial current density is J ₀ , the current efficiency η can be expressed by Equation (9).
η = L ₀ / J ₀ · exp [− (k · t) β] (9)
(K is a rate constant, and β is a parameter indicating initial degradation. Here, the rate is the rate at which the luminescent species are not luminescent species over time, and the faster the rate constant, the faster the degradation. become.). Therefore, equation (10) is obtained from equations (8) and (9).
_{L = J p · L 0 /} J 0 · exp [- (k · t) β] ··· (10)

Here, in order to make the luminance constant, L = L ₀ (= constant) must be satisfied, and therefore Expression (11) is obtained by substituting L = L ₀ into Expression (10).
J _p = J ₀ · exp [(k · t) β] (11)

In other words, it is considered that the constant luminance drive is approached by increasing J _p according to the equation (11). Then, Expression (12) is obtained from Expressions (7) and (11).
g (Q _p ) / g (Q _m ) = exp [(k · t) β] (12)

Further, it is considered that the constant luminance drive is approached by selecting Q _p and Q _m so that “g (Q _p ) / g (Q _m )” approaches exp [(k · t) β]. Therefore, by setting the duty ratio between the light emitting element and the monitor element so as to satisfy Expression (12), the accuracy of deterioration compensation can be further increased.

(Embodiment 5)
In this embodiment, a method for correcting deterioration with time of a light-emitting element in a pixel in a period in which display is not performed using the display device described in Embodiments 1 to 3 is described.

The degree of progress of the light emitting element over time is large in the initial stage and gradually decreases with time. Therefore, in a display device using light emitting elements, it is preferable to perform an initial aging process that causes an initial change over time of all the light emitting elements before adjusting the luminance of the light emitting elements (for example, before shipment). By performing such initial aging treatment and causing an initial rapid change over time of the light emitting element in advance, the change over time will not proceed rapidly thereafter, so that the seizure caused by the change over time may occur. The phenomenon can be reduced.

Note that the initial aging process is performed by turning on the light-emitting element for a certain period, but it is preferable to apply a higher voltage than in normal use. Then, the initial change with time will occur in a short time.

When the display device of the present invention is operated using a rechargeable battery, a process for lighting or blinking all pixels during charging that is not in use of the display device, a standard image (for example, a standby image) It is preferable to perform a process of displaying an image in which the brightness is inverted, a process of detecting a pixel with low lighting frequency by sampling a video signal, and a process of lighting or blinking the pixel. As described above, the above-described processing for reducing burn-in when not in use is called flash-out processing. If this flash-out process is performed, burn-in can be reduced after the process. Even if burn-in occurs, the difference between the brightest part and the darkest part of the burned-in image can be set to 5 gradations or less, more preferably 1 gradation. In order to reduce burn-in, in addition to the above-described processing, it is preferable to perform processing so as not to fix the image for as long as possible.

(Embodiment 6)
In this embodiment mode, a current-driven passive matrix display device in which a current is supplied from a current source to a monitor element and a column signal line is precharged using a voltage generated in the monitor element will be described.

First, FIG. 28 shows a schematic diagram of a column signal line driver circuit applicable to a passive matrix display device in the case where gradation is expressed by the length of light emission time. That is, the current values flowing to the column signal lines are equal, and the gradation is expressed by controlling the current supply time. Note that the column signal line driver circuit described in this embodiment can be applied to the display device illustrated in FIG. 1, and refer to Embodiment 1 for operations of the pixel portion 103 and the row signal line driver circuit 102.

A pulse output circuit 2801, a first latch circuit 2802, a second latch circuit 2803, a pulse width control circuit 2804, a current source circuit 2805, a switching circuit 2806, and a precharge circuit 2807 are provided.

The precharge circuit 2807 includes a current source 2808, a current supply switch 2811, a monitor element 2809, and an amplifier 2810. The current source 2808 is connected to the anode of the monitor element 2809 via a current supply switch 2811.

The switching circuit 2806 includes a light emission switch 2814 that switches between conduction and non-conduction between the current source 2812 at each stage of the current source circuit 2805 and the column signal line in each column. In addition, the switching circuit 2806 precharges the column signal line of the column in which the light emission switch 2814 is on, so that the precharge switch 2813 switches between the output terminal of the amplifier 2810 and the column signal line between conduction and non-conduction. have.

A clock signal (CLK), a start pulse signal (SP), and the like are input to the pulse output circuit 2801. A sampling pulse is output from the pulse output circuit 2801 in accordance with the timing of these signals.

The sampling pulse output from the pulse output circuit 2801 is input to the first latch circuit 2802. In addition, a video signal (DATA) is input to the first latch circuit 2802. Then, the video signal is held in each stage of the first latch circuit 2802 in accordance with the timing at which the sampling pulse is input.

When a latch pulse (SLAT) is input to the second latch circuit 2803, the video signals (DATA) held in the respective stages of the first latch circuit 2802 are transferred to the second latch circuit 2803 all at once. The

Then, the signal held in the second latch circuit 2803 is converted into a pulse having each pulse width by the pulse width control circuit 2804. Then, according to the pulse width of the pulse output from the pulse width control circuit 2804, a period for turning on the light emission switch 2814 in each stage of the switching circuit 2806 is set. Then, a current flows from each current source 2812 of the current source circuit 2805 in the stage where the light emission switch 2814 is turned on to the selected row signal line via each of the column signal lines S1 to Sn.

When the row signal lines of each row are sequentially selected, the current supply switch 2811 and the precharge switch 2813 are turned on immediately before or simultaneously with the selection of the row signal line. Then, current is supplied from the current source 2808 to the monitor element 2809. A voltage is generated between both electrodes of the monitor element 2809. At this time, the potential of the anode of the monitor element 2809 is input to the input terminal of the amplifier 2810. The amplifier 2810 outputs a potential approximately equal to that of the input terminal from the output terminal. This output is input to the column signal line via the switch 2813 in the stage where the light emission switch 2814 is on. At this time, current flows as shown in FIG. Actually, current also flows from the current source 2812. However, since the output impedance of the amplifier 2810 is low, the current flowing from the current source 2812 is small.

Thereafter, the current supply switch 2811 and the precharge switch 2813 are immediately turned off. As described above, since the amplifier 2810 has a low output impedance, the potential of the column signal line can be quickly made the potential of the anode of the monitor element 2809. That is, since the monitor element 2809 is formed of the same material as the light emitting element of the pixel, a potential necessary for flowing the current of the current source 2808 to the light emitting element is already input to the column signal line. Yes. Therefore, if the current values of the current source 2808 and the current source 2812 are made equal, a light emitting element composed of the column signal line at the stage where the light emission switch 2814 is turned on and the selected row signal line emits light quickly. Can be made. At this time, current flows as shown in FIG.

That is, as shown in FIG. 32A, in the precharge period, the current source 2808 and the monitor element 2809 are in conduction, and the amplifier 2810 has an input terminal connected to the anode of the monitor element 2809 and an output terminal emitting light. The element 3201 is electrically connected to the anode. Then, the current source 2812 and the anode of the light emitting element 3201 are made non-conductive. In addition, as illustrated in FIG. 32B, during the light emission period, the current source 2808 and the anode of the monitor element 2809 are turned off, and the current source 2812 and the anode of the light emitting element 3201 are turned on. Then, the output terminal of the amplifier 2810 is made non-conductive with the anode of the light emitting element 3201. What is necessary is just to connect in this way, and it is not restricted to a structure like FIG.

In addition, when the light emission switch 2814 is turned off, a potential may be input so that the light emitting elements of the pixels in the column immediately do not emit light. That is, as shown in FIG. 34, the column signal line and the wiring 3402 are connected via the switch 3401 that is turned on when the light emission switch 2814 is turned off. Note that the potential of the wiring 3402 is set to a potential at which the light-emitting element of the selected pixel is turned off.

In such a configuration, during the precharge period, as illustrated in FIG. 36A, the current source 2808 and the anode of the monitor element 2809 are electrically connected, and the amplifier 2810 has an input terminal connected to the anode of the monitor element 2809. The output terminal is electrically connected to the anode of the light emitting element 3201. Then, the current source 2812 and the anode of the light emitting element 3201 may be turned off or may be turned on. In addition, the wiring 3402 is not connected to the anode (column signal line) of the light-emitting element 3201.

In the light emission period, as shown in FIG. 36B, the current source 2808 and the anode of the monitor element 2809 are turned off, and the current source 2812 and the anode of the light emitting element 3201 are turned on. Then, the output terminal of the amplifier 2810 is made non-conductive with the anode of the light emitting element 3201. In addition, the wiring 3402 is not connected to the anode (column signal line) of the light-emitting element 3201.

When the light-emitting period of the pixels in the column ends, the current source 2812 and the anode of the light-emitting element 3201 are turned off and the anode of the light-emitting element 3201 is connected to the wiring 3402 as illustrated in FIG. To do.

Therefore, the connection may be made in this way, and the configuration is not limited to that shown in FIG.

Next, FIG. 30 shows a schematic diagram of the column signal line driver circuit of the passive matrix display device in the case where gradation is expressed by the difference in emission intensity.

A pulse output circuit 3001, a first latch circuit 3002, a second latch circuit 3003, and a power supply circuit 3004 are provided. Note that the power supply circuit 3004 includes a current source 3005, a monitor element 3006, an amplifier 3007, a first precharge switch 3008, a second precharge switch 3009, and a light emission switch 3010.

A clock signal (CLK), a start pulse signal (SP), and the like are input to the pulse output circuit 3001. A sampling pulse is output from the pulse output circuit 3001.

The sampling pulse output from the pulse output circuit 3001 is input to the first latch circuit 3002. In addition, a video signal (DATA) is input to the first latch circuit 3002. Then, the video signal is held in each stage of the first latch circuit 3002 in accordance with the input timing of the sampling pulse.

Then, when a latch pulse (SLAT) is input to the second latch circuit 3003, video signals held in the respective stages of the first latch circuit 3002 are transferred to the second latch circuit 3003 all at once.

Then, the video signal transferred to the second latch circuit 3003 determines the current value of the current source 3005 included in the power supply circuit 3004.

In the precharge period, the first precharge switch 3008 and the second precharge switch 3009 are turned on, and the light emission switch 3010 is turned off. Then, a current flows from the current source 3005 to the monitor element 3006 as shown in FIG. A voltage is generated between both electrodes of the monitor element 3006. At this time, the potential of the anode of the monitor element 3006 is input to the amplifier 3007. A potential substantially equal to the input is output from the output of the amplifier 3007. Therefore, the column signal line is charged with a potential necessary for flowing the current supplied from the current source 3005 to the light emitting element through the column signal line. Accordingly, as shown in FIG. 31B, the first precharge switch 3008 and the second precharge switch 3009 are turned off, and the light emission switch 3010 is turned on. Then, a current can be quickly passed from the current source 3005 to the light emitting element via the column signal line.

That is, when the current value supplied from the current source 3005 is small, it takes time to charge the load capacitance such as the wiring cross capacitance formed on the column signal line from the current source 3005. Then, it becomes impossible to obtain sufficient luminance according to the video signal. However, as in this configuration, the column signal line is charged with the current output from the amplifier 3007 during the precharge period, so that the load capacity of the column signal line can be quickly charged. Therefore, light emission with a desired luminance can be obtained quickly.

In addition, when the light emission switch 3010 is turned off, a potential may be input so that the light emitting elements of the pixels in the column immediately do not emit light. That is, as shown in FIG. 35, the column signal line and the wiring 3502 are connected via the switch 3501 that is turned on when the light emission switch 3010 is turned off. Note that the potential of the wiring 3502 is set to a potential at which the light-emitting element of the selected pixel is turned off.

In such a structure, in the precharge period, as shown in FIG. 37A, the current source 3005 and the monitor element 3006 are electrically connected, and the amplifier 3007 has an input terminal electrically connected to the anode of the monitor element 3006. The output terminal is electrically connected to the anode of the light emitting element 3301. Then, the current source 3005 and the light emitting element 3301 are turned off. The wiring 3502 is kept out of conduction with the anode (column signal line) of the light-emitting element 3301.

In the light emission period, as shown in FIG. 37B, the current source 3005 and the anode of the monitor element 3006 are turned off, and the current source 3005 and the anode of the light emitting element 3301 are turned on. Then, the output terminal of the amplifier 3007 is made non-conductive with the anode of the light emitting element 3301. The wiring 3502 is kept out of conduction with the anode (column signal line) of the light-emitting element 3301.

When the light emission period of the pixels in the column ends, as illustrated in FIG. 37C, the current source 3005 and the anode of the light emitting element 3301 are turned off and the anode of the light emitting element 3301 is connected to the wiring 3502. To do.

Therefore, the connection may be made in this way, and the configuration is not limited to that shown in FIG.

(Embodiment 7)
In this embodiment, a structure of a passive display panel that can be applied to the present invention will be described.

  FIG. 21A is a diagram illustrating a top view of the pixel portion before sealing. FIG. 21B is a cross-sectional view taken along the chain line AA ′ in FIG. FIG. 21C is a cross-sectional view taken along −B ′.

  On the first substrate 2110, a plurality of first electrodes 2113 are arranged in stripes at equal intervals. A partition 2114 having an opening corresponding to each pixel is provided over the first electrode 2113, and the partition 2114 having the opening has a light-shielding material (photosensitive material in which a black pigment or carbon black is dispersed). Or a non-photosensitive organic material (polyimide, acrylic, polyamide, polyimide amide, resist or benzocyclobutene) or SOG film (for example, an SiOx film containing an alkyl group). For example, a material such as COLOR MOSAIC CK (trade name) manufactured by Fuji Film Orin Co., Ltd. is used as the partition wall 2114 having an opening. A partition 2114 having an opening functions as a black matrix (BM). Note that an opening corresponding to each pixel is a light emitting region 2121. At this time, the monitor element is also integrally formed. Then, variation in element characteristics can be reduced, so that the accuracy of the compensation function is improved.

A plurality of reverse-tapered partition walls 2122 that are parallel to each other and intersect with the first electrode 2113 are provided over the partition wall 2114 having an opening. The inversely tapered partition wall 2122 is formed by using a positive photosensitive resin as a pattern in an unexposed portion and adjusting an exposure amount or a development time so that a lower portion of the pattern is etched more in accordance with a photolithography method. This inversely tapered partition wall 2122 may also be formed of the above-described light-shielding material to further improve the contrast. At this time, the light from the monitor element can be blocked by covering the monitor element with the material of the partition wall 2122.

  Further, FIG. 22 shows a perspective view immediately after forming a plurality of parallel reverse tapered partition walls 2122. In addition, the same code | symbol is used for the same part as FIG.

  The height of the inversely tapered partition wall 2122 is set larger than the thickness of the film containing an organic compound and the conductive film. When a film containing an organic compound and a conductive film are stacked over the first substrate having the structure shown in FIG. 22, the organic compound is separated into a plurality of electrically independent regions as shown in FIG. The layers 2115R, 2115G, and 2115B including the second electrode 2116 are formed. The second electrode 2116 is a striped electrode parallel to each other and extending in a direction intersecting the first electrode 2113. Note that a film containing an organic compound and a conductive film are also formed over the reverse-tapered partition wall 2122, but the layers 2115 R, 2115 G, and 2115 B containing an organic compound and the second electrode 2116 are separated.

  Here, an example is shown in which the layers 2115R, 2115G, and 2115B containing an organic compound are selectively formed to form a light-emitting device capable of full-color display capable of obtaining three types (R, G, and B) of light emission. The layers 2115R, 2115G, and 2115B containing an organic compound are formed in stripe patterns parallel to each other. In such a configuration, as described with reference to FIG. 15, it is preferable that the display device has a configuration in which the potential of the column signal line can be set for each RGB.

  Alternatively, a layer containing an organic compound may be formed over the entire surface and a single color light emitting element may be provided, or a light emitting device capable of monochrome display or a light emitting device capable of area color display may be used. Further, a light-emitting device that can emit white light may be a light-emitting device capable of full-color display by being combined with a color filter. In the present invention, since the partition 2114 functions as a black matrix, a color filter including only a colored layer is used. That's fine. In such a case, it is possible to apply a display device having a configuration in which a common potential is set to the column signal lines described in the best mode or the first to fifth embodiments.

  In addition, the light-emitting element is sealed by bonding the second substrate with a sealant. If necessary, a protective film covering the second electrode 2116 may be formed. Note that the second substrate is preferably a substrate having a high barrier property against moisture. Further, if necessary, a desiccant may be disposed in a region surrounded by the sealing material.

  In the case where the first electrode 2113 is a light-reflective conductive material and the second electrode 2116 is a light-transmitting conductive material, light emitted from the light-emitting element is allowed to pass through the second substrate. A top emission type light emitting device can be obtained. When an aluminum alloy (Al (C + Ni)) film containing carbon and nickel is used as the first electrode 2113 as a single layer or a lower layer of a transparent conductive film, contact with ITO or ITSO even after energization or heat treatment This is preferable because it is a material that does not vary greatly in resistance value. In this case, the light from the monitor element can be blocked by covering the monitor element with the material of the partition wall 2122.

In the case where the first electrode 2113 is a light-transmitting conductive material and the second electrode 2116 is a light-reflecting conductive material, light emitted from the light-emitting element is allowed to pass through the first substrate 2110. Thus, a bottom emission type light emitting device can be obtained. In this case, it is preferable to form a light-shielding film below the monitor element in advance.

In the case where both the first electrode 2113 and the second electrode 2116 are light-transmitting conductive materials, light emission from the light-emitting element is allowed to pass through the second substrate, and light emission from the light-emitting element is performed. A light-emitting device capable of both passing through the first substrate can be obtained. In this case, the light from the monitor element can be blocked by covering the monitor element with the material of the partition wall 2122 and forming a light-shielding film under the monitor element in advance.

  FIG. 23 shows a top view of a light emitting module on which an FPC or the like is mounted after sealing.

Note that a light-emitting device in this specification refers to an image display device, a light-emitting device, or a light source (including a lighting device). Also, a module in which a connector such as an FPC (Flexible printed circuit) or TAB (Tape Automated Bonding) tape or TCP (Tape Carrier Package) is attached to the light emitting device, or a module in which a printed wiring board is provided at the end of the TAB tape or TCP In addition, a module in which an IC (integrated circuit) is directly mounted on a light emitting element by a COG (Chip On Glass) method is also included in the light emitting device.

The first substrate 2301 and the second substrate 2310 are attached with a sealant 2311 so as to face each other. As the sealant 2311, a photo-curing resin may be used, and a material with low degassing and low hygroscopicity is preferable. Further, the sealant 2311 may be added with a filler (a rod-like or fiber-like spacer) or a spherical spacer in order to keep the substrate interval constant. Note that the second substrate 2310 is preferably made of a material having the same thermal expansion coefficient as that of the first substrate 2301, and glass (including quartz glass) or plastic can be used.

As shown in FIG. 23, in the pixel portion constituting the image display, the row signal line group and the column signal line group intersect so that they are orthogonal to each other.

  The first electrode 2113 in FIG. 21 corresponds to the column signal line 2302 in FIG. 23, the second electrode 2116 corresponds to the row signal line 2303, and the inversely tapered partition 2122 corresponds to the partition 2304. A layer containing an organic compound is sandwiched between the column signal line 2302 and the row signal line 2303, and an intersection indicated by 2305 corresponds to one pixel.

  Note that the row signal line 2303 is electrically connected to the connection wiring 2308 at a wiring end, and the connection wiring 2308 is connected to the FPC 2309 b through the input terminal 2307. The column signal line is connected to the FPC 2309a via the input terminal 2306.

  Further, if necessary, an optical film such as a polarizing plate or a circular polarizing plate (including an elliptical polarizing plate), a retardation plate (λ / 4 plate, λ / 2 plate), a color filter, or the like is appropriately provided on the exit surface. Also good. Further, an antireflection film may be provided on the polarizing plate or the circularly polarizing plate. For example, anti-glare treatment can be performed that diffuses reflected light due to surface irregularities and reduces reflection. Moreover, you may perform the anti-reflection process which heat-processes to a polarizing plate or a circularly-polarizing plate. Thereafter, in order to protect from external impact, a hard coat treatment may be performed. However, when a polarizing plate or a circularly polarizing plate is used, the light extraction efficiency decreases due to the polarizing plate or the circularly polarizing plate. In addition, the cost of the polarizing plate or the circularly polarizing plate itself is high and easily deteriorates.

In the present invention, a black partition (also referred to as a bank or a barrier) serving as a black matrix (BM) is provided between pixels on a substrate side where a light-emitting element is provided, and stray light from the light-emitting element is absorbed or shielded. Thus, the display contrast can be improved.

Further, an example of manufacturing a light-emitting module on which an IC chip is mounted will be described with reference to FIGS.

  First, a column signal line (anode) 2402 having a stacked structure in which a lower layer is a reflective metal film and an upper layer is a transparent oxide conductive film is formed over a first substrate 2401. At the same time, connection wirings 2408, 2409a, and 2409b and an input terminal are formed. At this time, the monitor element group 2415 is also formed at the same time.

  Next, a partition wall having an opening corresponding to each pixel is provided. COLOR MOSAIC CK (trade name) manufactured by Fuji Film Orin Co., Ltd. is used as the partition wall having the opening. Next, a plurality of reverse-tapered partition walls 2404 that are parallel to each other and intersect the column signal line 2402 are provided over the partition walls having openings.

  FIG. 24A shows a top view at the stage where the above steps are completed.

  Next, when a film including an organic compound and a transparent conductive film are stacked, the organic compound is separated into a plurality of electrically independent regions as illustrated in FIG. The row signal line 2403 is formed. The row signal line 2403 made of a transparent conductive film is a stripe-shaped electrode extending in the direction intersecting with the column signal line 2402 and parallel to each other.

  Next, a second substrate 2414 having a light-transmitting property is attached with a sealant 2413.

  Next, the column signal line side IC 2406 and the row signal line side IC 2407 in which a driving circuit for transmitting each signal to the pixel portion is formed in a peripheral (outside) region of the pixel portion, respectively, are mounted by a COG method. You may mount using TCP and a wire bonding system as mounting techniques other than a COG system. TCP is an IC mounted on a TAB tape, and the IC is mounted by connecting the TAB tape to a wiring on an element formation substrate. The column signal line side IC 2406 and the row signal line side IC 2407 may be those using a silicon substrate, or may be a glass substrate, a quartz substrate, or a plastic substrate formed with a drive circuit using TFTs. . In addition, although an example in which one IC is provided on one side is shown, it may be divided into a plurality of parts on one side.

  Note that the row signal line 2403 is electrically connected to the connection wiring 2408 at the wiring end, and the connection wiring 2408 is connected to the row signal line side IC 2407. This is because it is difficult to provide the row signal line side IC 2407 on the inversely tapered partition wall 2404.

  The column signal line side IC 2406 provided in the above configuration is connected to the FPC 2411 through the connection wiring 2409a and the input terminal 2410. The row signal line side IC 2407 is connected to the FPC through the connection wiring 2409b and the input terminal.

  Further, an IC chip 2412 (memory chip, CPU chip, power supply circuit chip, etc.) is mounted for integration.

Note that the light-emitting module described in FIGS. 24 and 25 can be applied to the structure of the display device described in FIG. That is, the row signal line side IC 2407 corresponds to the row signal line driver circuit 1402 in FIG. 19, and the column signal line IC 2406 corresponds to the column signal line driver circuit in FIG. The monitor element group 2415 corresponds to the monitor elements 1901a to 1901m in FIG. The IC chip 2412 includes a current source 1405 and an amplifier 1404.

FIG. 25 shows an example of a cross-sectional structure taken along the chain line CD in FIG.

A base insulating film 11 is provided on the first substrate 10, and a column signal line made of a laminate is formed thereon. The lower layer 12 is a reflective metal film, and the upper layer 13 is a transparent oxide conductive film. The upper layer 13 is preferably a conductive film having a high work function. In addition to indium tin oxide (ITO), for example, indium tin oxide containing Si element (ITSO) or indium oxide with 2 to 20% zinc oxide ( A film containing a transparent conductive material such as IZO (Indium Zinc Oxide) mixed with ZnO) or a combination of these materials can be used. In particular, ITSO does not crystallize like ITO even when baked and remains in an amorphous state. Therefore, ITSO has higher flatness than ITO, and even if the layer containing an organic compound is thin, short-circuiting with the cathode hardly occurs, so that ITSO is suitable as an anode of a light-emitting element.

  The lower layer 12 uses Ag, Al, or an Al (C + Ni) alloy film. Among them, an Al (C + Ni) film (an aluminum alloy film containing carbon and nickel (1 to 20 wt%)) is preferable because it is a material that does not greatly change the contact resistance value with ITO or ITSO even after energization or heat treatment.

  The partition wall 14 for insulating adjacent column signal lines is a black resin and serves as a black matrix (BM) that overlaps a boundary with a different colored layer (provided on the sealing substrate side) or a gap. . The region surrounded by the black partition has the same area corresponding to the light emitting region.

  The layer 15 containing an organic compound is, in order from the column signal line (anode) side, HIL (hole injection layer), HTL (hole transport layer), EML (light emitting layer), ETL (electron transport layer), EIL (electron injection layer). Are stacked in this order. Note that the layer containing an organic compound can have a single-layer structure or a mixed structure in addition to a stacked structure.

The row signal line 16 (cathode) is formed so as to intersect with the column signal line (anode). As the row signal line 16 (cathode), a transparent conductive film such as ITO, indium tin oxide containing Si element (ITSO), or IZO in which 2 to 20% zinc oxide (ZnO) is mixed with indium oxide is used. In the present invention, the row signal line 16 is important because it is an example of a top emission type light emitting device in which light emission passes through the sealing substrate 20.

Further, not all of the light generated in the layer 15 containing an organic compound is extracted from the row signal line 16 made of a transparent conductive film through the second substrate 20, for example, in the lateral direction (parallel to the substrate surface). Direction) but as a result, the light emitted in the lateral direction is not taken out, resulting in a loss. In the present invention, stray light from the light emitting element is absorbed or shielded by the partition wall 14 made of black resin.

In addition, a transparent protective film that covers the row signal line 16 may be provided in order to protect the light emitting element from damage caused by moisture or degassing. As a transparent protective film, a dense inorganic insulating film (SiN, SiNO film, etc.) by a PCVD method, a dense inorganic insulating film (SiN, SiNO film, etc.) by a sputtering method, a thin film (DLC film, CN film, amorphous carbon film), metal oxide film (WO ₂ , CaF ₂ , Al ₂ O ₃ etc.) are preferably used. Transparent means that the transmittance of visible light is 80 to 100%.

In addition, the pixel portion and the monitor element portion including the light emitting element are sealed with the sealing material 19 and the second substrate 20, and the enclosed space is sealed. In addition, a light shielding film may be provided on the monitor element portion so that light is not emitted to the outside.

As the sealing material 19, an ultraviolet curable resin, a thermosetting resin, a silicone resin, an epoxy resin, an acrylic resin, a polyimide resin, a phenol resin, PVC (polyvinyl chloride), PVB (polyvinyl butyral), or EVA (ethylene vinyl acetate) is used. It is possible. Further, the sealing material may be a filler added with a filler (bar-shaped or fiber-shaped spacer) or a spherical spacer.

Further, a glass substrate or a plastic substrate is used as the second substrate 20. As the plastic substrate, polyimide, polyamide, acrylic resin, epoxy resin, PES (polyether sulfone), PC (polycarbonate), PET (polyethylene terephthalate) or PEN (polyethylene naphthalate) may be used in the form of a plate or film. it can.

  The sealed space 18 is filled with a dry inert gas. A minute amount of moisture is removed from the inner sealed space 18 surrounded by the sealing material 19 by the desiccant 17 and is sufficiently dried. Further, as the desiccant 17, a substance that absorbs moisture by chemical adsorption, such as an oxide of an alkaline earth metal such as calcium oxide or barium oxide, can be used. As another desiccant, a substance that adsorbs moisture by physical adsorption, such as zeolite or silica gel, may be used.

  On the other hand, a terminal electrode is formed at the end of the substrate 10, and an FPC (flexible printed wiring board) 32 connected to an external circuit is bonded to this portion. The terminal electrode is composed of a laminate of a reflective metal film 30, a transparent oxide conductive film 29, and an oxide conductive film extending from the second electrode, but is not particularly limited.

As a method for mounting the FPC 32, a connection method using an anisotropic conductive material or a metal bump, or a wire bonding method can be adopted. In FIG. 25, the anisotropic conductive adhesive 31 is used for connection.

  Further, around the pixel portion, an IC chip 23 on which a drive circuit for transmitting each signal to the pixel portion is formed is electrically connected by anisotropic conductive materials 24 and 25. In order to form a pixel portion corresponding to color display, the number of column signal lines is 3072 in the XGA class, and 768 row signal lines are required. The column signal lines and row signal lines formed in such numbers are divided into several blocks at the end of the pixel portion to form lead lines, which are collected according to the pitch of the output terminals of the IC. Note that 33 is a light-shielding film, 26 is a transparent oxide conductive film, and 27 is a reflective metal film.

  The light-emitting device described above is a top emission type light-emitting device that performs display using light emission indicated by an arrow in FIG. 25, and the contrast is improved by the black partition 14.

  An example in which an optical film is provided on the display panel will be described with reference to FIG.

  An optical film 26121 is provided over a second substrate 26120 provided to face the first substrate 26110. In this embodiment, an example in which light is emitted in a direction indicated by an arrow in FIG. 26A, that is, an example in which light emitted from the light-emitting element passes through the second substrate 26120 and then passes through the optical film 26121 is shown. However, there is no particular limitation, and an optical film may be provided on the first substrate side, and light emitted from the light-emitting element may pass through the second substrate 26120 after passing through the optical film 26121.

  The optical film 26121 refers to an optical film such as a polarizing plate, a circularly polarizing plate (including an elliptically polarizing plate), a retardation plate (λ / 4 plate, λ / 2 plate), a color filter, or the like.

  A light-emitting element in a pixel of a passive matrix light-emitting device includes a layer including a column signal line (anode) having a stacked structure in which a lower layer 26112 is a reflective metal film, an upper layer 26113 is a transparent oxide conductive film, and an organic compound. 26115 and a row signal line 26116 made of a transparent conductive film. Further, the partition wall 26114 is formed of a light-blocking material.

  When a circularly polarizing plate is used as the optical film 26121, it is possible to prevent external light from being reflected on the lower layer 26112 and reducing the visibility of the image. The circularly polarizing plate is specifically a combination of a retardation plate, a retardation film, a polarizing plate, a polarizing film, or a linear polarizing film having retardation characteristics of λ / 4, λ / 4 + λ / 2. A circularly polarizing plate (including an elliptical polarizing plate). The broadband λ / 4 plate here gives a constant phase difference (90 degrees) in the visible light range. Specifically, a circularly polarizing plate is set so that the angle formed by the transmission axis of the polarizing plate and the slow axis of the retardation film is 45 °. In this specification, the circularly polarizing plate includes a circularly polarizing film.

  Further, when the light-emitting element is a white light-emitting element and a color filter is used as the optical film 26121, full-color display can be achieved.

  A plurality of types of optical films may be appropriately combined.

  An example of a bottom emission light-emitting device is described with reference to FIG.

  The light-emitting element in this embodiment includes a column signal line (anode) 26213 made of a transparent oxide conductive film, a layer 26215 containing an organic compound, and a row signal line 26216 made of a reflective conductive film. ing. In addition, the partition wall 26214 is formed using a light-blocking material.

  Light emission from the light-emitting element is extracted in a direction indicated by an arrow in FIG. 26B, that is, a direction passing through the first substrate 26210. Therefore, the second substrate 26221 does not need to have a light transmitting property and may be a metal plate. In addition, it is preferable to form a thick protective film 26217 in order to improve the reliability of the light emitting element because the light extraction efficiency does not decrease.

  In addition, the structure in FIG. 26B can be freely combined with the best mode and Embodiments 1 to 5. For example, when an optical film is provided in combination with the best mode, Embodiment Modes 1 to 5, an optical film may be provided over the first substrate 26210.

  An example in which the light-emitting device is different from that in FIGS. 26A and 26B will be described with reference to FIG.

  26C includes a column signal line (anode) 26313 made of a transparent oxide conductive film, a layer 26315 containing an organic compound, and a row signal line 26316 made of a transparent oxide conductive film. is doing. Further, the partition wall 26314 is formed using a light-blocking material.

  Light emission from the light-emitting element is extracted in both directions indicated by arrows in FIG. 26C, that is, a direction passing through the first substrate 26310 and a direction passing through the second substrate 26320. Therefore, both the first substrate 26310 and the second substrate 26320 are substrates having light transmittance.

  In addition, the structure in FIG. 26C can be freely combined with the best mode, Embodiment Modes 1 to 5. For example, when an optical film is provided in combination with the best mode and Embodiments 1 to 5, the optical film may be provided on both the first substrate 26310 and the second substrate 26320.

  Further, an example in which the partition wall is not a reverse taper shape but a forward taper shape will be described with reference to FIG. 27 is substantially the same as FIG. 21 except for the shape of the partition wall and the light emitting element (white).

  In the same manner as in FIG. 21, a striped first electrode 2713 is formed over the first substrate 2710. In FIG. 27, a partition 2714 having an opening is provided over the first electrode 2713, and a partition including a spacer 2721 and a wide overhang body 2722 on the spacer 2721 is formed thereon.

  The spacer 2721 uses an organic resin film such as polyimide, and the overhang body 2722 uses a photosensitive resin film such as a resist. An organic resin film such as polyimide is formed, and a pattern of a photosensitive resin film such as a resist is left between electrodes to be separated. Then, the exposed organic resin film is etched. Etching conditions are adjusted so that an undercut is generated below the pattern of the photosensitive resin during the etching. By these steps, an element isolation structure having an overhang structure, that is, a partition wall can be formed.

  In FIG. 27, a partition wall 2714 having an opening, a spacer 2721, or an overhang body 2722 is formed using a light-blocking material to improve contrast.

  After the partition shown in FIG. 27 is formed, a layer 2715 containing the organic compound and the second electrode 2716 can be formed by forming a layer containing an organic compound and a transparent conductive film.

In FIG. 27, a layer 2715 containing an organic compound is laminated, and two-layer light emission is performed using a laminate of a green light emitting layer in which Alq ₃ is doped with coumarin 6 and a yellow light emitting layer in which TPD is doped with rubrene. The white light emitting element used is used. In the present embodiment, since the step of painting for each emission color can be omitted, the manufacturing time of the passive matrix light emitting device can be shortened.

  In order to achieve full color display, the second substrate 2720 is provided with a color filter including only the colored layers 2719R, 2719G, and 2719B in a position facing the pixels of the white light-emitting element.

  The configuration of FIG. 27 can be applied to the case where the potential of each column signal line is a common potential in the display device described in the best mode, Embodiment Modes 1 to 5. Since the light-emitting element of the pixel portion is only a white light-emitting element, the monitor element is formed of the same material, so that the element characteristics can be uniformed, so that the accuracy of the compensation function can be further improved.

(Embodiment 8)
Mobile devices such as television devices (TVs, television receivers), digital cameras, digital video cameras, mobile phone devices (mobile phones), PDAs, and the like as electronic devices using display devices having pixel regions including light-emitting elements Examples thereof include a terminal, a portable game machine, a monitor, a computer, an audio playback device such as a car audio, and an image playback device equipped with a recording medium such as a home game machine. The display device of the present invention can be applied to display portions of these electronic devices. A specific example of the electronic device will be described with reference to FIG.

A portable information terminal using the display device of the present invention illustrated in FIG. 18A includes a main body 9201, a display portion 9202, and the like. Power consumption can be reduced by the present invention. A digital video camera using the display device of the present invention illustrated in FIG. 18B includes display portions 9701 and 9702, and the present invention can reduce power consumption. A mobile phone using the display device of the present invention illustrated in FIG. 18C includes a main body 9101, a display portion 9102, and the like. Power consumption can be reduced by the present invention. A portable television device using the display device of the present invention illustrated in FIG. 18D includes a main body 9301, a display portion 9302, and the like. Power consumption can be reduced by the present invention. A portable computer using the display device of the present invention illustrated in FIG. 18E includes a main body 9401, a display portion 9402, and the like. Power consumption can be reduced by the present invention. A television set using the display device of the present invention illustrated in FIG. 18F includes a main body 9501, a display portion 9502, and the like, and can reduce power consumption according to the present invention. Among the electronic devices mentioned above, those using a battery can extend the usage time of the electronic device by reducing the power consumption, and can save the trouble of charging the battery.

As described above, the display device of the present invention can be applied to various electronic devices. .

In addition, the display device having a compensation function of the present invention can maintain a certain luminance, and thus can be called a constant luminance display device. The driving method of the display device having a compensation function as in the present invention can be called a constant luminance driving method (constant brightness method, constant luminescence method, brightness control method, control brightness method, brightness control method). . In this driving method, as described above, the increase in the current value due to the compensation function and the decrease in the current value due to the change over time are obtained in advance, and the light emitting element is driven under a voltage condition in which these are just canceled. This is a driving method.

The schematic diagram of the display apparatus of this invention. FIG. 6 illustrates a column signal line driver circuit and a compensation circuit. FIG. 6 illustrates a column signal line driver circuit and a compensation circuit. FIG. 6 illustrates a column signal line driver circuit and a compensation circuit. FIG. 6 illustrates a column signal line driver circuit and a compensation circuit. 3A and 3B illustrate a structure of a switch that can be applied to the present invention. FIG. 6 illustrates a column signal line driver circuit and a compensation circuit. FIG. 6 illustrates a column signal line driver circuit and a compensation circuit. FIG. 6 illustrates a column signal line driver circuit and a compensation circuit. 6A and 6B illustrate temperature dependency of voltage / current characteristics of an EL element. The figure of the voltage-current characteristic explaining the time-dependent deterioration of EL element. The figure of the voltage-current characteristic explaining the temporal deterioration by the duty ratio of a light emitting element and a monitor element. A timing chart of a 3-bit time gradation. 4A and 4B illustrate a display device having a structure in which a plurality of monitor elements are arranged. The figure explaining the display apparatus of the structure which has arrange | positioned multiple monitor elements for every RGB. Initial characteristics, IV characteristics after storage for 1000 hours and after driving for 1000 hours. The figure explaining the change of n and S after an initial state, 1000hr preservation | save, and 1000hr drive. FIG. 14 illustrates an electronic device including the display device of the invention. 4A and 4B illustrate a display device having a structure in which a plurality of monitor elements are arranged. 4A and 4B illustrate a display device having a structure in which a plurality of monitor elements are arranged. 3A and 3B illustrate a top surface structure and a cross-sectional structure of a display panel. The perspective view of a display panel. The top view which shows the external appearance of a light emitting module. The top view of a light emitting module. Sectional drawing of a light emitting module. The figure explaining the emission direction of light. FIG. 14 is a diagram showing another example of a cross-sectional structure of a display panel. FIG. 10 illustrates a column signal line driver circuit. 4A and 4B illustrate an operation of a column signal line driver circuit. FIG. 10 illustrates a column signal line driver circuit. 4A and 4B illustrate an operation of a column signal line driver circuit. 4A and 4B illustrate connection of a column signal line driver circuit. 4A and 4B illustrate connection of a column signal line driver circuit. FIG. 10 illustrates a column signal line driver circuit. FIG. 10 illustrates a column signal line driver circuit. 4A and 4B illustrate connection of a column signal line driver circuit. 4A and 4B illustrate connection of a column signal line driver circuit.

Claims (6)

A first light emitting element including a column signal line, a row signal line, a layer including an organic compound sandwiched between a part of the column signal line and a part of the row signal line, a first electrode, and the row signal; A second light-emitting element formed of a layer containing an organic compound sandwiched between part of the lines, a current source, and an amplifier,
A first electrode of the second light emitting element is electrically connected to the current source;
A first electrode of the second light emitting element is electrically connected to an input terminal of the amplifier;
An output terminal of the amplifier is electrically connected to the column signal line. A first light emitting element including a column signal line, a row signal line, a layer including an organic compound sandwiched between a part of the column signal line and a part of the row signal line, a first electrode, and the row signal; A plurality of second light-emitting elements each including a layer containing an organic compound sandwiched between part of the wires, a current source, and an amplifier,
A first electrode of each of the plurality of second light emitting elements is electrically connected to the current source;
Each first electrode of the plurality of second light emitting elements is electrically connected to an input terminal of the amplifier,
An output terminal of the amplifier is electrically connected to the column signal line. Oite to claim 2, wherein the plurality of second light emitting element, a display apparatus characterized by being electrically connected in parallel. An electronic apparatus, comprising a display unit to display device according to any one of claims 1 to 3. A first light emitting element including a column signal line, a row signal line, a layer including an organic compound sandwiched between a part of the column signal line and a part of the row signal line, a first electrode, and a second electrode; A second light-emitting element including a layer containing an organic compound sandwiched between, a first current source, a second current source, and an amplifier,
During the precharge period,
Supplying a current from the first current source to the second light emitting element;
The potential of the first electrode of the second light emitting element is input to the input terminal of the amplifier,
From the output terminal of the amplifier, a potential approximately equal to the potential of the first electrode of the second light emitting element is output to the column signal line,
During the flash period,
A driving method of a display device, wherein a current is supplied from the second current source to the first light emitting element to cause the light emitting element to emit light. A first light emitting element including a column signal line, a row signal line, a layer including an organic compound sandwiched between a part of the column signal line and a part of the row signal line, a first electrode, and a second electrode; A second light-emitting element including a layer containing an organic compound sandwiched between, a current source, and an amplifier,
During the precharge period,
Supplying a current from the current source to the second light emitting element;
The potential of the first electrode of the second light emitting element is input to the input terminal of the amplifier,
From the output terminal of the amplifier, a potential approximately equal to the potential of the first electrode of the second light emitting element is output to the column signal line,
During the flash period,
A driving method of a display device, wherein a current is supplied from the current source to the first light emitting element to cause the light emitting element to emit light.

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