JP2006309260A - Pixel circuit, display device and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a decrease in screen luminance and screen unevenness by properly correcting aged deterioration if the aged deterioration includes decreases in current quantity and light emission quantity of a current driving type light emitting element or has variation. <P>SOLUTION: A pixel circuit provided for each of pixels arranged in a matrix comprises the current driving type light emitting element 224 connected between a first power feeding line 213 and a second power feeding line 215, a first thin film transistor element 223 which controls a driving current flowing to the light emitting element through the source and drain, which are connected between the first and second feeding lines in series with the light emitting element, according to the voltage of a data signal supplied to the gate, a holding capacitor 222, and driving current compensating elements 231 to 234 which increase the driving current in accordance with a decrease in current quantity of the driving current by adjusting the resistance between the first power feeding line 213 and second power feeding line 214 or the resistance between one of the first and second power feeding lines and the holding capacitor depending upon the relation between the voltage of both ends of the light emitting element and the current quantity of the driving current. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pixel circuit configured to include a light emitting element and a driving element such as a thin film transistor for driving the light emitting element, a display device configured to include such a pixel circuit in each pixel, and an electronic apparatus including the same. In particular, the present invention relates to a technical field of a pixel circuit and a display device capable of correcting the influence of deterioration over time of a light emitting element and a driving element, and an electronic apparatus including these.

As this type of display device, a display device using a thin film transistor (hereinafter referred to as TFT) as a drive element and driving a current-driven light emitting element such as an organic EL element is configured as follows, for example. That is, a data signal and a scanning signal corresponding to an image to be displayed are supplied from the scanning line driving circuit and the signal line driving circuit to the signal line and the scanning line in the display area, respectively. On the other hand, from the common electrode driving circuit and the counter electrode driving circuit, between the pixel electrode and the counter electrode in each pixel via the driving TFT provided in each of the plurality of pixels defined in a matrix in the display area. A voltage is applied. Then, at the timing when the scanning signal is supplied from the scanning line by the driving TFT of each pixel, the current driving type light emission disposed between the pixel electrode and the counter electrode according to the voltage of the data signal supplied from the signal line. The current flowing through the element is configured to be controlled.
More specifically, for example, each pixel is provided with a switching TFT, and when a scanning signal is supplied to the gate from the scanning line, a data signal from the signal line is sent via the source and drain to the driving TFT. Supply to the gate. The conductance between the source and drain of the driving TFT is controlled (changed) in accordance with the voltage of the data signal (that is, the gate voltage) supplied to the gate in this way. At this time, the gate voltage is held for a longer period than the period in which the data signal is supplied by the storage capacitor connected to the gate. The drive current is supplied to the organic EL element or the like through the source and drain whose conductance is controlled in this way, so that the organic EL element or the like is driven according to the drive current.

  In particular, the organic EL element provided with the driving TFT as described above is used as a current control type light emitting element (hereinafter referred to as TFT-OELD) for realizing a display panel having a large size, high definition, wide viewing angle, and low power consumption. Promising.

However, in a current-driven light-emitting element such as an organic EL element, since a drive current flows in the element, deterioration with time exists to a greater or lesser extent. For example, in the case of an organic EL element, it is reported that there is a remarkable deterioration with time (Jpn. J. Appl. Phys., 34, L824 (1995)). The deterioration with time of the organic EL element is roughly classified into two types. One is deterioration in which the amount of current decreases with respect to the voltage applied to the organic EL element. The other is deterioration in which the amount of light emission decreases with respect to the voltage applied to the organic EL element or the current flowing through the organic EL element. Further, the deterioration with time occurs with variation for each organic EL element. Further, in the TFT-OEL, deterioration of the TFT over time may occur due to a current flowing through the TFT as a driving element.

  For this reason, in a display device using a TFT-OEL, when such an organic EL element or a driving TFT deteriorates with time, image quality deterioration becomes a problem. That is, deterioration in which the amount of current decreases and deterioration in which the amount of light emission decreases causes a decrease in screen brightness, and variations in the amount of current decrease and variations in the amount of light emission cause screen unevenness. In particular, these deteriorations depend on the light emission characteristics of the organic EL elements at the time of manufacture, variations in the voltage / current characteristics and threshold characteristics of the driving TFT, the history of the display pattern, and the like, leading to deterioration of the image quality of the entire display device. At the same time, it causes screen unevenness.

Here, for example, in Patent Document 1, an EL element is used as a back light source (backlight) of a liquid crystal display panel, and the EL display element is illuminated so that the brightness of the entire liquid crystal display panel illuminated from behind is not reduced. A technique for detecting the luminance of the element and correcting the deterioration of the entire back light source is disclosed. However, this technology relates to a liquid crystal display panel, and EL elements are not provided in each pixel as display elements, but are used as mere back light sources. Are related to different technical fields. In a display device configured by including a current-driven light-emitting element such as an organic EL element in each pixel, an effective technique for correcting the above-described deterioration with time has not been proposed. Further, in a display device provided with such a current-driven light-emitting element in each pixel, the lifetime of the display device is extended or the display quality is improved by correcting deterioration with time in the current-driven light-emitting element and the driving TFT. At present, the technical problem itself is not recognized by those skilled in the art.
Japanese Patent Laid-Open No. 05-019234

  In view of this, the present invention corrects the deterioration over time when the deterioration with time in which the amount of current and the amount of light emission in the current-driven light emitting element decreases or when the deterioration with time varies, thereby reducing the screen brightness. Another object of the present invention is to provide a pixel circuit and a display device including a current-driven light-emitting element that can reduce screen unevenness and an electronic device including these.

  A pixel circuit according to one embodiment of the present invention includes a display region of a display device including at least a signal wiring to which a data signal is supplied and first and second power supply lines to which power for supplying a driving current is supplied. A pixel circuit provided in each of the plurality of matrix-like pixels, wherein the current-driven light-emitting element connected between the first and second power supply lines and the first and second power supply lines A first thin film transistor element for controlling the drive current flowing through the light emitting element through a source and a drain connected in series with the light emitting element according to a voltage of the data signal supplied to a gate; and both ends of the light emitting element By adjusting the resistance between the first power supply line and the second power supply line depending on the relationship between the voltage of the drive current and the current amount of the drive current, according to the decrease in the current amount of the drive current The drive power Characterized in that a driving current compensation device for increasing the.

  A pixel circuit according to another aspect of the present invention includes a display region of a display device provided with at least a signal wiring to which a data signal is supplied and first and second power supply lines to which power for supplying a driving current is supplied. A pixel circuit provided in each of a plurality of matrix-shaped pixels constituting a current-driven light-emitting element connected between the first and second power supply lines, and between the first and second power supply lines A first thin film transistor element configured to control the drive current flowing through the light emitting element via a source and a drain connected in series with the light emitting element according to a voltage of the data signal supplied to a gate; Depending on the relationship between the holding capacity for holding the gate voltage of the first thin film transistor, the voltage across the light emitting element, and the amount of the drive current. A drive current compensation element that increases the drive current according to a decrease in the amount of the drive current by adjusting a resistance between one of the first and second feeder lines and the storage capacitor; It is characterized by that.

    Furthermore, the present invention has the following features.

  (1) According to a first display device of the present invention, a current drive type light emitting element provided for each pixel and a drive current that is provided for each pixel and flows through the light emitting element according to a voltage of a data signal. A driving element to be controlled; a power supply unit that supplies power to flow the driving current to the light emitting element through the driving element; and a data signal to the driving element through the signal wiring A signal wiring driving unit, and a current amount of driving current flowing through the light emitting element and a light emission amount of light emitted from the light emitting element when a data signal having a predetermined voltage is supplied to the driving element through the signal wiring A voltage adjustment unit that adjusts at least one of a power supply in the power supply unit and a data signal in the signal wiring drive unit so that at least one approaches a predetermined reference value. That.

  According to the first display device, a driving current flows to the light emitting element through the driving element by the power supply from the power supply unit. On the other hand, a data signal is supplied to the driving element from the signal wiring driving unit via the signal wiring. And the drive current which flows into a light emitting element is controlled by the drive element according to the voltage of a data signal. As a result, the current drive type light emitting element emits light corresponding to the voltage of the data signal by the drive current. Here, for example, when a data signal having a predetermined voltage is supplied to the drive element via the signal wiring in the non-display period, the voltage adjustment unit causes the amount of drive current flowing through the light emitting element or the light emitted from the light emitting element. The voltage of at least one of the power supply in the power supply unit and the data signal in the signal wiring drive unit is adjusted so that the light emission amount approaches a predetermined reference value (that is, the reference current amount or the reference light emission amount).

  Therefore, even when the light emitting element or the driving element is deteriorated with time, the resistance of the light emitting element or the driving element increases, so that it becomes difficult for the driving current to flow or the light emitting element becomes difficult to emit light. The amount or the amount of light emission is substantially constant. That is, a decrease in the drive current amount and the light emission amount due to deterioration of the light emitting element and the drive element over time can be appropriately corrected by voltage adjustment by the voltage adjustment unit.

  Furthermore, if voltage adjustment by the voltage adjustment unit is performed individually for a plurality of pixels, even if there are variations in the voltage-current characteristics and current light-emission characteristics of the light-emitting elements and drive elements among the plurality of pixels, The drive current amount or the light emission amount in the light emitting element of the pixel can be made substantially constant. That is, it is possible to appropriately correct the variation in the drive current amount and the light emission amount due to the variation in the characteristics of the light emitting element and the drive element.

  As a result, according to the first display device, in a display device in which a current-driven light-emitting element such as an organic EL element is driven by a driving element such as a thin film transistor, the screen brightness decreases due to deterioration with time and characteristic variation of each element. And screen unevenness can be reduced.

  (2) In one aspect of the first display device, the driving element is a thin film transistor in which the driving current flows between a source and a drain whose conductance is controlled by a gate voltage while the data signal is supplied to the gate. Consists of.

  According to this aspect, when a data signal is supplied to the gate of the thin film transistor, the conductance between the source and the drain is controlled (changed) by the gate voltage. Therefore, the drive current flowing through the light emitting element through the source and drain can be controlled according to the voltage of the data signal.

  (3) In another aspect of the first display device, the voltage adjustment unit measures a current amount of the drive current when the data signal of the predetermined voltage is supplied to the drive element; A voltage control unit that adjusts the at least one voltage so that the measured current amount approaches a preset reference current amount.

  According to this aspect, the current amount of the drive current when the data signal having the predetermined voltage is supplied to the drive element is measured by the current amount measurement unit. Then, the voltage of the data signal or the power supply voltage of the drive current is adjusted by the voltage control unit so that the measured current amount approaches the preset reference current amount.

  Accordingly, even when the light emitting element or the driving element is deteriorated with time and the resistance of the light emitting element or the driving element is increased to make it difficult for the driving current to flow, the amount of driving current in the light emitting element is substantially constant. Furthermore, even if the voltage-current characteristics of the light emitting element and the driving element vary among the plurality of pixels, if the voltage adjustment of the data signal is performed individually for each pixel, the light emitting elements of the plurality of pixels The amount of drive current can be made substantially constant.

  (4) In another aspect of the first display device, the voltage adjustment unit is configured to measure a light emission amount measurement unit that measures the light emission amount when a data signal of the predetermined voltage is supplied to the drive element. A voltage control unit that adjusts at least one of the voltages so that the emitted light amount approaches a preset reference light amount.

  According to this aspect, the light emission amount of the light emitting element when the data signal of the predetermined voltage is supplied to the drive element is measured by the light emission amount measuring unit. Then, the voltage of the data signal or the power supply voltage of the drive current is adjusted by the voltage control unit so that the measured light emission amount approaches a preset reference light emission amount.

  Therefore, even when the light emitting element or the driving element becomes difficult to emit light due to an increase in resistance of the light emitting element or the driving element due to the deterioration of the light emitting element or the driving element over time, the light emission amount in the light emitting element is made substantially constant. Furthermore, even if the voltage-current characteristics and current-emission characteristics of the light-emitting elements and drive elements vary among the plurality of pixels, if the voltage adjustment of the data signal is performed individually for each pixel, the plurality of pixels The amount of drive current in the light emitting element can be made substantially constant.

  (5) In another aspect of the first display device, the controller further includes a controller that controls the voltage adjusting unit so as to adjust the at least one voltage during a non-display period preceding the display period.

  According to this aspect, under the control of the controller, the voltage of the data signal or the power supply voltage of the drive current is adjusted by the voltage adjustment unit in the non-display period preceding the display period.

  Therefore, it is not necessary to occupy a part of the display period for the measurement, and at the same time, the voltage adjustment unit appropriately adjusts the voltage, and the adjustment operation does not adversely affect the image display in the display period. In view of the progress rate of deterioration over time in the light emitting element and the driving element, for example, it is often sufficient to perform adjustment by the power supply adjustment unit for each non-display period such as when the power is turned on.

  (6) In order to solve the above technical problem, the second display device of the present invention is provided with a current-driven display light emitting element provided for each pixel in the display region and for each pixel. A drive element for controlling a drive current flowing through the display light emitting element according to a voltage of a data signal, and a power source for supplying the drive current to the display light emitting element through the drive element are supplied via a power supply wiring A power supply unit that supplies the data signal to the drive element via a signal line, and a current drive type that is provided in the monitor region and is current-driven in the same manner as the display light emitting element. Among the power source in the power source unit and the data signal in the signal wiring driving unit so that at least one of the monitor light emitting element and the current amount and the light emission amount in the monitor light emitting element approaches a predetermined reference value Characterized by comprising a voltage adjusting unit for adjusting the one voltage even without.

  According to the second display device, a driving current flows through the display light emitting element through the driving element by the power supply from the power supply unit. On the other hand, a data signal is supplied to the driving element from the signal wiring driving unit via the signal wiring. The drive element controls the drive current flowing in the display light emitting element according to the voltage of the data signal. As a result, the current-driven display light emitting element emits light corresponding to the voltage of the data signal by the drive current. Here, for example, when a data signal having a predetermined voltage is supplied to the drive element via the signal wiring in the non-display period, the voltage adjustment unit performs current drive similarly to the display light-emitting element. The voltage of at least one of the power supply in the power supply unit and the data signal in the signal wiring drive unit is adjusted so that the current amount or the light emission amount in the light emitting element approaches a predetermined reference value (that is, the reference current amount or the reference light emission amount). . Here, in particular, since the monitor light emitting element provided in the monitor region is driven by current in the same manner as the display light emitting element provided in the display region, deterioration with time in the monitor light emitting element is caused in the display light emitting element. It is considered to have a similar or similar tendency to deterioration over time.

  Therefore, even if the display light-emitting element and the drive element are deteriorated with time, the resistance of the display light-emitting element and the drive element is increased, so that the drive current is difficult to flow or the display light-emitting element is difficult to emit light. The drive current amount or the light emission amount in the display light emitting element is substantially constant. That is, a decrease in the drive current amount and the light emission amount due to the deterioration of the display light emitting element and the drive element over time can be appropriately corrected by adjusting the voltage of the voltage adjustment unit based on the current amount and the light emission amount in the monitor light emitting element.

  Furthermore, if voltage adjustment by the voltage adjustment unit is performed individually for a plurality of pixels, even if there are variations in the voltage-current characteristics and current light-emission characteristics of the light-emitting elements and drive elements among the plurality of pixels, The drive current amount or the light emission amount in the light emitting element of the pixel can be made substantially constant. That is, it is possible to appropriately correct the variation in the drive current amount and the light emission amount due to the variation in the characteristics of the light emitting element and the drive element.

  As a result, according to the second display device, in a display device in which a current-driven light-emitting element such as an organic EL element is driven by a driving element such as a thin film transistor, the screen brightness decreases due to deterioration with time or characteristic variation of each element. And screen unevenness can be reduced.

  (7) In one aspect of the second display device, the driving element is a thin film transistor in which the driving current flows through a source and a drain whose conductance is controlled by a gate voltage while the data signal is supplied to the gate. Consists of.

  According to this aspect, when a data signal is supplied to the gate of the thin film transistor, the conductance between the source and the drain is controlled (changed) by the gate voltage. Therefore, the drive current flowing through the light emitting element for display via the source and drain can be controlled according to the voltage of the data signal.

  (8) In another aspect of the second display device, the voltage adjustment unit includes a current amount measurement unit that measures a current amount in the monitor light emitting element, and a reference current in which the measured current amount is set in advance. And a voltage control unit that adjusts the at least one voltage so as to approach the amount.

  According to this aspect, the current amount in the monitor light emitting element is measured by the current amount measuring unit. Then, the voltage of the data signal or the power supply voltage of the drive current is adjusted by the voltage control unit so that the measured current amount approaches the preset reference current amount.

  Accordingly, even when the light emitting element or the driving element is deteriorated with time and the resistance of the light emitting element or the driving element is increased to make it difficult for the driving current to flow, the amount of driving current in the light emitting element is substantially constant. Furthermore, even if the voltage / current characteristics of the light emitting element and the driving element vary among the plurality of pixels, if the voltage adjustment is performed for each pixel individually, the amount of driving current in the light emitting element of the plurality of pixels Can be made almost constant.

  (9) In another aspect of the second display device, the voltage adjustment unit includes a light emission amount measurement unit that measures the light emission amount in the monitor light emitting element, and a reference light emission in which the measured light emission amount is preset. And a voltage control unit that adjusts the at least one voltage so as to approach the amount.

  According to this aspect, the light emission amount in the monitor light emitting element is measured by the light emission amount measurement unit. Then, the voltage of the data signal or the power supply voltage of the drive current is adjusted by the voltage control unit so that the measured light emission amount approaches a preset reference light emission amount.

  Therefore, even when the light emitting element or the driving element becomes difficult to emit light due to an increase in resistance of the light emitting element or the driving element due to the deterioration of the light emitting element or the driving element over time, the light emission amount in the light emitting element is made substantially constant. Furthermore, even if the voltage-current characteristics and current-emission characteristics of the light-emitting elements and drive elements vary among the plurality of pixels, if the voltage adjustment of the data signal is performed individually for each pixel, the plurality of pixels The amount of drive current in the light emitting element can be made substantially constant.

  (10) In another aspect of the second display device, the display device further includes a controller that controls the voltage adjusting unit so as to adjust the at least one voltage during a non-display period preceding the display period.

  According to this aspect, under the control of the controller, the voltage of the data signal or the power supply voltage of the drive current is adjusted by the voltage adjustment unit in the non-display period preceding the display period. Therefore, while the voltage adjustment unit appropriately adjusts the voltage, the adjustment operation does not adversely affect the image display in the display period.

  (11) In another aspect of the second display device, the display light-emitting element and the monitor light-emitting element are formed on the same substrate.

  According to this aspect, by operating the display light-emitting element and the monitor light-emitting element in a similar or similar environment, the tendency of deterioration with time in both can be made similar or similar. Therefore, the voltage adjustment for the display light emitting element can be performed with high accuracy based on the current amount and the light emission amount in the monitor light emitting element.

  (12) In another aspect of the second display device, the display light-emitting element and the monitor light-emitting element are formed by the same manufacturing process.

  According to this aspect, since a separate manufacturing process is not required for manufacturing the monitor light emitting element, it is advantageous in manufacturing. In addition, the characteristics of the display light-emitting element and the monitor light-emitting element can be made to be similar or similar to each other relatively easily. Therefore, the tendency of deterioration with time in both can be made similar or similar.

  (13) In another aspect of the second display device, the power supply unit supplies power for flowing the drive current to both the display light emitting element and the monitor light emitting element during a display period.

  According to this aspect, since the drive current is supplied to both the display light-emitting element and the monitor light-emitting element during the display period, the tendency of deterioration with time in both can be made similar or similar.

  (14) In order to solve the above technical problem, the pixel circuit of the present invention is provided with at least a signal wiring to which a data signal is supplied and first and second power supply lines to which power for supplying a driving current is supplied. A pixel circuit provided in each of a plurality of matrix-like pixels constituting a display area of the display device, wherein the current-driven light-emitting element is connected between the first and second feeder lines; A first current that controls the drive current flowing through the light emitting element via a source and a drain connected in series with the light emitting element between the first and second feeder lines in accordance with a voltage of the data signal supplied to the gate. A thin film transistor (a thin film transistor for current control), and a driving current that increases the driving current in accordance with at least one of a decrease in the amount of driving current and a decrease in the amount of light emitted from the light emitting element. Characterized in that a compensating element.

  According to the pixel circuit of the present invention, the drive current flows through the light emitting element through the source and the drain of the first thin film transistor by the power supply from the first and second power supply lines. On the other hand, a data signal is supplied to the gate of the first thin film transistor through a signal wiring. Then, the conductance between the source and drain of the first thin film transistor is controlled (changed) by the gate voltage, and the drive current flowing through the light emitting element is controlled according to the voltage of the data signal. As a result, the current-driven light emitting element emits light corresponding to the voltage of the data signal by the drive current. The drive current flowing in this way is increased by the drive current compensation element in accordance with the decrease in the drive current amount or the light emission amount of the light emitting element.

  Therefore, even when the light emitting element and the first thin film transistor are deteriorated with time, the resistance of the light emitting element and the first thin film transistor increases, and thus it becomes difficult for the driving current to flow or the light emitting element becomes difficult to emit light. The drive current amount or the light emission amount is made substantially constant. That is, it is possible to automatically correct the decrease in the drive current amount and the light emission amount due to the deterioration of the light emitting element and the first thin film transistor over time by the action of increasing the drive current due to the resistance decrease by the drive current compensation element.

  Furthermore, since such correction is performed individually for a plurality of pixels, even if there are variations in the voltage-current characteristics and the current emission characteristics of the light-emitting elements and the first thin film transistors among the plurality of pixels, The drive current amount or the light emission amount in the light emitting element can be made substantially constant. That is, it is possible to automatically correct the variation in the drive current amount and the light emission amount due to the variation in the characteristics of the light emitting element and the first thin film transistor.

  As a result, according to the pixel circuit of the present invention, in a pixel circuit that drives a current-driven light-emitting element such as an organic EL element by the first thin film transistor, a decrease in screen brightness due to deterioration with time and characteristic variation of each element or screen Unevenness can be reduced.

  (15) In one aspect of the pixel circuit, the signal wiring includes a signal line to which the data signal is supplied and a scanning line to which the scanning signal is supplied, and the source and drain are supplied to the gate while the scanning signal is supplied to the gate. A second thin film transistor (switching thin film transistor) connected so that the data signal is supplied to the gate of the first thin film transistor through the first thin film transistor.

  According to this aspect, when a scanning signal is supplied to the gate of the second thin film transistor through the scanning line, the source and drain of the second thin film transistor are brought into conduction. In parallel with this, when a data signal is supplied to the source or drain of the second thin film transistor through the signal line, the data signal is supplied to the gate of the first thin film transistor through the source and drain of the second thin film transistor. The

  (16) In another aspect of the pixel circuit, the drive current compensation element depends on a relationship between a voltage at both ends of the light emitting element and a current amount of the drive current, and the first feed line and the second supply line. Adjust the resistance between the wires.

  According to this aspect, the resistance between the first feed line and the second feed line is adjusted by the drive current compensation element depending on the relationship between the voltage across the light emitting element and the amount of drive current. Thus, the drive current is increased in accordance with a decrease in the amount of drive current.

  (17) In an aspect in which the adjustment is performed depending on the relationship between the voltage and the current amount, the potential of the first feeding line is set to be higher than that of the second feeding line, and the driving current compensating element is , An n-channel type first electrode having a gate connected to the electrode on the first feeder line side of the light emitting element, and a source and a drain connected in series with the light emitting element between the light emitting element and the second feeder line. One correction thin film transistor may be included.

  In this case, the resistance between the first power supply line and the second power supply line is adjusted by the n-channel first correction thin film transistor, and the drive current is increased in accordance with a decrease in the amount of drive current. It is done.

  (18) Alternatively, in an aspect in which adjustment is performed depending on the relationship between the voltage and the current amount, the potential of the first power supply line is set lower than that of the second power supply line, and the drive current compensation is performed. The device has a p-channel type in which a gate is connected to the electrode on the first feeder line side of the light emitting element, and a source and a drain are connected in series with the light emitting element between the light emitting element and the second feeder line. The first correction thin film transistor may be included.

  In this case, the resistance between the first power supply line and the second power supply line is adjusted by the p-channel first correction thin film transistor, and the drive current is increased in accordance with the decrease in the amount of drive current. It is done.

  (19) Alternatively, in the aspect of adjusting depending on the relationship between the voltage and the current amount, the potential of the first power supply line is set higher than that of the second power supply line, and the drive current compensation is performed. The device has a p-channel type in which a gate is connected to the electrode on the second feeder line side of the light emitting element, and a source and a drain are connected in series with the light emitting element between the light emitting element and the first feeder line. The second correction thin film transistor may be included.

  In this case, the resistance between the first power supply line and the second power supply line is adjusted by the second correction thin film transistor of the p-channel type, and the drive current is increased in accordance with the decrease in the amount of drive current. It is done.

  (20) Alternatively, in the aspect of adjusting depending on the relationship between the voltage and the current amount, the potential of the first power supply line is set lower than that of the second power supply line, and the drive current compensation is performed. The element has an n-channel type in which a gate is connected to the electrode on the second feeder line side of the light emitting element, and a source and a drain are connected in series with the light emitting element between the light emitting element and the first feeder line. The second correction thin film transistor may be included.

  In this case, the resistance between the first power supply line and the second power supply line is adjusted by the n-channel second correction thin film transistor, and the drive current is increased in accordance with the decrease in the amount of drive current. It is done.

  (21) In another aspect of the pixel circuit, the pixel circuit further includes a storage capacitor connected to a gate of the first thin film transistor and configured to hold a gate voltage of the first thin film transistor.

  According to this aspect, the gate voltage of the first thin film transistor after the data signal is supplied is held by the holding capacitor. Therefore, it is possible to flow the drive current through the source and drain of the first thin film transistor over a period longer than the period for supplying the data signal.

  (22) In the aspect provided with this storage capacitor, the drive current compensation element depends on the relationship between the voltage across the light emitting element and the amount of the drive current. You may comprise so that the resistance between one side and the said retention capacity | capacitance may be adjusted.

  According to this aspect, the resistance between the first or second feeder line and the storage capacitor is adjusted by the drive current compensation element depending on the relationship between the voltage across the light emitting element and the amount of drive current. As a result, the drive current is increased in accordance with a decrease in the amount of drive current.

  (23) In the aspect in which the resistance between the power supply line and the storage capacitor is adjusted in this way, the potential of the first power supply line is set higher than that of the second power supply line, and the drive current compensation is performed. The element has the same n or the same as the first thin film transistor in which the gate is connected to the electrode on the first feeder line side of the light emitting element, and the source and drain are connected between the storage capacitor and the first feeder line. A p-channel third correction thin film transistor may be included.

  In this case, the resistance between the first or second power supply line and the storage capacitor is adjusted by the same n- or p-channel third correction thin film transistor as that of the first thin film transistor, and the second power supply from the first power supply line is adjusted. The drive current is increased according to a decrease in the amount of drive current flowing toward the electric wire.

  (24) Alternatively, in the aspect in which the resistance between the feeder line and the storage capacitor is adjusted in this way, the potential of the first feeder line is set to be lower than that of the second feeder line, and the drive The current compensation element is the same as the first thin film transistor in which the gate is connected to the electrode on the first feeder line side of the light emitting element, and the source and drain are connected between the storage capacitor and the first feeder line. An n- or p-channel third correction thin film transistor may be included.

  In this case, the resistance between the first or second power supply line and the storage capacitor is adjusted by the same n- or p-channel third correction thin film transistor as that of the first thin film transistor, and the first supply from the second power supply line is adjusted. The drive current is increased according to a decrease in the amount of drive current flowing toward the electric wire.

  (25) Alternatively, in the aspect in which the resistance between the power supply line and the storage capacitor is adjusted in this way, the potential of the first power supply line is set to a higher potential than the second power supply line, and the drive The current compensation element is opposite to the first thin film transistor in which a gate is connected to an electrode on the first feeder line side of the light emitting element, and a source and a drain are connected between the storage capacitor and the second feeder line. The fourth correction thin film transistor of n or p channel type may be included.

  In this case, the resistance between the first or second power supply line and the storage capacitor is adjusted by the fourth n- or p-channel correction thin film transistor opposite to the first thin film transistor, and the second power supply line extends from the first power supply line to the second power supply line. The drive current is increased in accordance with a decrease in the amount of drive current flowing toward the feeder line.

  (26) Alternatively, in the aspect of adjusting the resistance between the feeder line and the storage capacitor in this way, the potential of the first feeder line is set to be lower than that of the second feeder line, and the drive The current compensation element is opposite to the first thin film transistor in which a gate is connected to an electrode on the first feeder line side of the light emitting element, and a source and a drain are connected between the storage capacitor and the second feeder line. The fourth correction thin film transistor of n or p channel type may be included.

  In this case, the resistance between the first or second power supply line and the storage capacitor is adjusted by an n- or p-channel fourth correction thin film transistor opposite to the first thin film transistor, so that the first power supply line is connected to the first power supply line. The drive current is increased in accordance with a decrease in the amount of drive current flowing toward the feeder line.

  (27) In another aspect of the pixel circuit, the drive current compensation element may be connected between the first feeder line and the second feeder line depending on the relationship between the voltage across the light emitting element and the light emission amount. Adjust the resistance between.

  According to this aspect, depending on the relationship between the voltage at both ends of the light emitting element and the light emission amount, the resistance between the first power supply line and the second power supply line is adjusted by the drive current compensation element, thereby emitting light. The drive current is increased in accordance with a decrease in the light emission amount of the element.

  (28) Further, in the aspect including the above-described storage capacitor, the drive current compensation element depends on the relationship between the voltage across the light emitting element and the light emission amount, and the first and second feeders You may comprise so that the resistance between one side and the said retention capacity | capacitance may be adjusted.

  According to this aspect, depending on the relationship between the voltage across the light emitting element and the light emission amount, the resistance between the first or second feeder and the storage capacitor is adjusted by the drive current compensation element, The drive current is increased according to the decrease in the amount of light emission.

  (29) In such an aspect in which the resistance between the feeder line and the storage capacitor is adjusted depending on the relationship between the voltage and the light emission amount, the potential of the first feeder line is higher than that of the second feeder line. The first thin film transistor is a p-channel type, and the drive current compensation element is a first correction thin film photodiode connected between the storage capacitor and the first feeder. You may comprise so that it may contain.

  In this case, the resistance between the first or second power supply line and the storage capacitor is adjusted by the first correction thin film photodiode, and the second power supply from the first power supply line to the p-channel first thin film transistor is performed. The drive current flowing toward the electric wire is increased according to the decrease in the amount of light emission.

  (30) Alternatively, in the aspect in which the resistance between the feeder line and the storage capacitor is adjusted depending on the relationship between the voltage and the light emission amount, the potential of the first feeder line is more than that of the second feeder line. Is set to a high potential, the first thin film transistor is a p-channel type, and the driving current compensation element has a source and a drain connected between the storage capacitor and the first feeder line. The correction thin film transistor may be included.

  In this case, the resistance between the first or second feeding line and the storage capacitor is adjusted by the fifth correction thin film transistor, and the first feeding line to the second feeding line with respect to the p-channel first thin film transistor. The drive current that flows toward the front is increased according to the decrease in the amount of light emission.

  (31) Alternatively, in the aspect in which the resistance between the feeder line and the storage capacitor is adjusted depending on the relationship between the voltage and the light emission amount, the potential of the first feeder line is more than that of the second feeder line. Is set to a low potential, the first thin film transistor is of an n-channel type, and the drive current compensation element is a first correction thin film connected between the storage capacitor and the first power supply line. You may comprise so that a photodiode may be included.

  In this case, the resistance between the first or second power supply line and the storage capacitor is adjusted by the first correction thin film photodiode, and the first power supply is supplied from the second power supply line to the n-channel first thin film transistor. The drive current flowing toward the electric wire is increased according to the decrease in the amount of light emission.

  (32) Alternatively, in the aspect in which the resistance between the power supply line and the storage capacitor is adjusted depending on the relationship between the voltage and the light emission amount, the potential of the first power supply line is higher than that of the second power supply line. Is set to a low potential, the first thin film transistor is an n-channel type, and the drive current compensating element has a source and a drain connected between the storage capacitor and the first feeder line. The correction thin film transistor may be included.

  In this case, the resistance between the first or second feeding line and the storage capacitor is adjusted by the fifth correction thin film transistor, and the second feeding line to the first feeding line with respect to the n-channel first thin film transistor. The drive current that flows toward the front is increased according to the decrease in the amount of light emission.

  (33) Alternatively, in the aspect in which the resistance between the feeder line and the storage capacitor is adjusted depending on the relationship between the voltage and the light emission amount, the potential of the first feeder line is more than that of the second feeder line. Is set to a high potential, the first thin film transistor is an n-channel type, and the drive current compensation element is a second thin film for correction connected between the storage capacitor and the second feed line. You may comprise so that a photodiode may be included.

  In this case, the resistance between the first or second power supply line and the storage capacitor is adjusted by the second correction thin film photodiode, and the second power supply is supplied from the first power supply line to the n-channel first thin film transistor. The drive current flowing toward the electric wire is increased according to the decrease in the amount of light emission.

  (34) Alternatively, in the aspect in which the resistance between the feeder line and the storage capacitor is adjusted depending on the relationship between the voltage and the light emission amount, the potential of the first feeder line is more than that of the second feeder line. Is set to a high potential, the first thin film transistor is an n-channel type, and the drive current compensation element has a source and a drain connected between the storage capacitor and the second feeder line. The correction thin film transistor may be included.

  In this case, the resistance between the first or second feeding line and the storage capacitor is adjusted by the sixth correction thin film transistor, and the first feeding line to the second feeding line with respect to the n-channel first thin film transistor. The drive current that flows toward the front is increased according to the decrease in the amount of light emission.

  (35) Alternatively, in the aspect in which the resistance between the feeder line and the storage capacitor is adjusted depending on the relationship between the voltage and the light emission amount, the potential of the first feeder line is more than that of the second feeder line. Is set to a low potential, the first thin film transistor is of a p-channel type, and the drive current compensation element is a second thin film for correction connected between the storage capacitor and the second feeder line. You may comprise so that a photodiode may be included.

  In this case, the resistance between the first or second feeding line and the storage capacitor is adjusted by the second correction thin film photodiode, and the first feeding from the second feeding line to the p-channel first thin film transistor is performed. The drive current flowing toward the electric wire is increased according to the decrease in the amount of light emission.

  (36) Alternatively, in the aspect in which the resistance between the feeder line and the storage capacitor is adjusted depending on the relationship between the voltage and the light emission amount, the potential of the first feeder line is more than that of the second feeder line. Is set at a low potential, the first thin film transistor is a p-channel type, and the drive current compensation element has a source and a drain connected between the storage capacitor and the second feeder line. The correction thin film transistor may be included.

  In this case, the resistance between the first or second feeding line and the storage capacitor is adjusted by the sixth correction thin film transistor, and the second feeding line to the first feeding line with respect to the p-channel first thin film transistor. The drive current that flows toward the front is increased according to the decrease in the amount of light emission.

  (37) In another aspect of the pixel circuit, the drive current compensation element includes a thin film transistor formed by the same manufacturing process as the first thin film transistor.

  According to this aspect, there is no need for a separate manufacturing process in order to manufacture the drive current compensation element, which is advantageous in manufacturing.

  (38) In order to solve the above technical problem, the third display device of the present invention is a current-driven light emitting element provided for each pixel, and is provided for each pixel and flows to the light emitting element. A drive element that controls the drive current according to the voltage of the data signal, a power supply unit that supplies power to the light emitting element through the drive element via the drive element, and an image signal source A signal line driving circuit for supplying a data signal having a voltage corresponding to an input image signal to the driving element via a signal line, and a data signal having a predetermined voltage supplied to the driving element via the signal line And a measurement unit that measures at least one of the amount of driving current flowing through the light emitting element and the amount of light emitted from the light emitting element, and is interposed between the image signal source and the signal line driving circuit. The above-mentioned measurement At least one of the current amount and the amount of light emission is is characterized in that a correcting circuit to be input to the signal line driving circuit after correcting the image signal so as to approach a predetermined reference value.

  According to the third display device, a driving current flows to the light emitting element through the driving element by the power supply from the power supply unit. On the other hand, a data signal having a voltage corresponding to the image signal input from the image signal source is supplied to the drive element from the signal line drive circuit via the signal line. And the drive current which flows into a light emitting element is controlled by the drive element according to the voltage of a data signal. As a result, the current drive type light emitting element emits light corresponding to the voltage of the data signal by the drive current. Here, for example, when a data signal having a predetermined voltage is supplied to the drive element via the signal line in the non-display period, the measurement unit measures the amount of drive current flowing through the light-emitting element or the light emission amount of the light-emitting element. The The image signal is corrected by the correction circuit so that the current amount or the light emission amount thus measured approaches a predetermined reference value (that is, the reference current amount or the reference light emission amount). Then, the corrected image signal is input to the signal line driver circuit. Therefore, a data signal having a voltage corresponding to the corrected image signal is supplied to the driving element from the signal line driving circuit via the signal line.

  Therefore, even when the light emitting element or the driving element is deteriorated with time, the resistance of the light emitting element or the driving element increases, so that it becomes difficult for the driving current to flow or the light emitting element becomes difficult to emit light. The amount or the amount of light emission is substantially constant.

  Further, if correction by the correction circuit is performed individually for a plurality of pixels, even if there are variations in voltage-current characteristics and current-light emission characteristics of the light-emitting elements and drive elements between the plurality of pixels, the plurality of pixels The driving current amount or the light emission amount of the light emitting element can be made almost constant.

  As a result, according to the third display device, in a display device in which a current drive type light emitting element such as an organic EL element is driven by a drive element such as a thin film transistor, the screen brightness is lowered due to deterioration with time and characteristic variation of each element. And screen unevenness can be reduced.

  (39) In one aspect of the third display device, the driving element is a thin film transistor in which the driving current flows through a source and a drain whose conductance is controlled by a gate voltage while the data signal is supplied to the gate. Consists of.

  According to this aspect, when a data signal is supplied to the gate of the thin film transistor, the conductance between the source and the drain is controlled (changed) by the gate voltage. Therefore, the drive current flowing through the light emitting element through the source and drain can be controlled according to the voltage of the data signal.

  (40) In another aspect of the third display device, the display device further includes a memory device that stores at least one of the measured current amount and the light emission amount, and the correction circuit includes the stored current amount and light emission. The image signal is corrected based on at least one of the quantities.

  According to this aspect, the measured current amount or light emission amount is stored in the memory device. The image signal is corrected by the correction circuit based on the stored current amount or light emission amount. Therefore, correction in the display period can be performed by measurement in the non-display period that is temporally related to the display period. Furthermore, it is possible to perform correction for a plurality of pixels using the same measurement unit and correction circuit.

  (41) In another aspect of the third display device, the power supply wiring is provided corresponding to a pixel column, and the measurement unit measures the amount of the drive current and displays the power supply wiring. A changeover switch connected to the power supply unit side during a period and connected to the measurement unit side during a non-display period, a shift register that sequentially outputs pulses corresponding to each of the power supply lines, and the non-display period And a common line driving circuit including a transmission switch for sequentially controlling conduction between each of the power supply wirings and the measuring unit according to the sequential pulse.

  According to this aspect, in the common line drive circuit, the power supply wiring is connected to the power supply unit side by the changeover switch during the display period. Accordingly, the light emitting element emits light upon receiving power supply from the power supply unit and performs a normal display operation. On the other hand, during the non-display period, the power supply wiring is connected to the measurement unit side by a changeover switch. At this time, the shift register sequentially outputs pulses corresponding to each of the power supply lines, and the transmission switch sequentially establishes conduction between each of the power supply lines and the measurement unit according to the pulses. Then, the amount of drive current is measured by the measurement unit. Therefore, by sequentially selecting the power supply wiring provided corresponding to the pixel column as the measurement target, it is possible to measure the current amount for each pixel column, and further, the configuration in which the light emitting element is driven for each row using the scanning signal. If this is adopted, it is possible to measure the amount of current for each pixel. As a result, correction can be performed for each pixel column or for each pixel.

  (42) In another aspect of the third display device, the measurement unit measures the light emission amount and transmits an electric signal indicating the light emission amount provided to the pixel column to the measurement unit. Light detection, a shift register that sequentially outputs a pulse corresponding to each of the light detection, and a continuity control between each of the light detection and the measurement unit according to the sequential pulse during a non-display period And a light detection drive circuit including a transmission switch for transmitting the light.

  According to this aspect, during the non-display period, pulses are sequentially output from the shift register corresponding to each of the detection lights, and the transmission switch sequentially outputs the pulses between each of the detection lights according to the pulses. Are sequentially conducted. Then, the light emission amount is measured by the measurement unit. Therefore, the light emission amount for each pixel column can be measured by sequentially selecting the detection light provided corresponding to the pixel column as a measurement target, and the light emitting element is driven for each row using the scanning signal. If this is adopted, it is possible to measure the light emission amount for each pixel. As a result, correction can be performed for each pixel column or for each pixel.

  (43) In another aspect of the third display device, the measurement unit measures the light emission amount by a photoexcitation current of a semiconductor element.

  According to this aspect, the light emission amount of the light emitting element is measured by the measurement unit by the photoexcitation current of the semiconductor element, and correction is performed based on the measured light emission amount. Therefore, it is possible to perform highly accurate measurement using a relatively simple element.

  (44) In the aspect of measuring by the photoexcitation current of the semiconductor element as described above, the semiconductor element may be a PIN diode.

  In this case, the light emission amount of the light emitting element can be measured by the photoexcitation current at the PIN junction of the PIN diode.

  (45) Alternatively, in the aspect of measuring by the photoexcitation current of the semiconductor element as described above, the semiconductor element may be a field effect transistor.

  In this case, the light emission amount of the light emitting element can be measured by the photoexcitation current in the channel portion of the field effect transistor.

  (46) Alternatively, in the aspect of measuring by the photoexcitation current of the semiconductor element as described above, the driving element may be formed of a thin film transistor, and the thin film transistor and the semiconductor element may be formed in the same process. .

  According to this aspect, the driving element and the semiconductor element can be formed in the same process, which is advantageous in manufacturing.

  (47) In another aspect of the third display device, the drive element comprises a polycrystalline silicon thin film transistor formed by a low temperature process of 600 ° C. or lower.

  According to this aspect, it becomes possible to produce a drive element having a high drive capability on a relatively low-priced large glass substrate or the like at a low cost.

  (48) In another aspect of the third display device, the light-emitting element comprises an organic electroluminescence element formed by an inkjet process.

  According to this aspect, a light emitting element with high luminous efficiency and a long lifetime can be produced, and patterning on the substrate can be easily performed. Further, since the amount of waste material in the process is small and the process equipment is also relatively inexpensive, it is possible to reduce the cost of the display device.

  (49) In another aspect of the third display device, the measurement unit performs measurement of at least one of the drive current and the light emission amount for each pixel, and the correction circuit outputs the image signal for each pixel. to correct.

  According to this aspect, the measurement of the drive current or the light emission amount is performed for each pixel by the measurement unit, and the image signal is corrected for each pixel by the correction circuit. Therefore, even if there is a variation such as a variation due to a difference in the degree of deterioration due to a manufacturing variation or a display history in a voltage-current characteristic or a current light-emission characteristic of a light-emitting element or a driving element among a plurality of pixels, The drive current amount or the light emission amount in the light emitting element of the pixel can be made almost constant. As a result, screen unevenness due to characteristic variations of each element can be reduced in detail.

  (50) In another aspect of the third display device, the measurement unit measures at least one of the drive current and the light emission amount for each predetermined unit including a plurality of pixels, and the correction circuit includes the predetermined circuit. The image signal is corrected for each unit.

  According to this aspect, the measurement of the drive current or the light emission amount is performed by the measurement unit for each predetermined unit composed of a plurality of pixels, and the image signal is corrected for each predetermined unit by the correction circuit. The predetermined unit is composed of, for example, n pixels (n = 2, 4, 8, 16, 32, 64,...) Adjacent to each other, and the number thereof depends on the required luminance uniformity, measurement unit, It may be determined according to the processing capability of the correction circuit. Therefore, even if there are variations in the voltage-current characteristics and current-emission characteristics of the light-emitting elements and drive elements among a plurality of predetermined units due to differences in the degree of deterioration due to manufacturing variations and display histories, etc. The drive current amount or the light emission amount in the light emitting element of the predetermined unit can be made substantially constant. As a result, screen unevenness due to characteristic variations of each element can be reduced efficiently. Such measurement and correction can be easily performed in a relatively short time as compared with the case of performing measurement and correction for each pixel.

  (51) In another aspect of the third display device, the correction circuit corrects the image signal by converting the signal level of the image signal from a predetermined signal level to another predetermined signal level.

  According to this aspect, since the signal level of the image signal is converted from a predetermined signal level to another predetermined signal level during correction by the correction circuit, a signal level different from the predetermined signal level is provided. There is no need to keep it. Thereby, for example, the configuration of the signal line driving circuit can be simplified, and the types of power supplies required for the signal line driving circuit can be reduced. As a result, the circuit can be simplified, the operation speed can be increased, and the current consumption can be reduced as the display device.

  (52) In order to solve the above technical problem, a fourth display device of the present invention is provided with the pixel circuit according to the various aspects of the present invention described above for each pixel.

  According to the fourth display device, since the pixel circuit of the present invention is provided for each pixel, a high-quality image in which a decrease in screen luminance and screen unevenness due to deterioration with time and characteristic variation in the light emitting element and the driving element are reduced. Display is possible.

  (53) An electronic apparatus according to the present invention includes any one of the first, second, and third display devices in the various aspects of the present invention described above in order to solve the above technical problem. To do.

  According to the electronic device of the present invention, since the display device of the present invention is provided, a high-quality image display in which a decrease in screen brightness and screen unevenness due to deterioration with time and characteristic variations in light emitting elements and drive elements is possible. Various electronic devices can be realized.

  The best mode for carrying out the present invention will be described below with reference to the drawings for each embodiment.

  First, FIG. 1 and FIG. 2 show a basic configuration common to a display device provided with TFT-OELD (that is, a driving thin film transistor and an organic EL element driven by current by the thin film transistor) of each embodiment described below. The description will be given with reference. FIG. 1 is a block diagram illustrating a basic overall configuration of the display device, and particularly includes a circuit diagram illustrating a basic circuit configuration of a pixel circuit provided in each of four adjacent pixels. FIG. 2 is a plan view of one pixel of the display device.

  As shown in FIG. 1, the display device 100 includes a plurality of scanning lines 131 extending in the X direction and arranged in the Y direction on the TFT array substrate 1, and extending in the Y direction and arranged in the X direction. The plurality of signal lines 132 and the plurality of common lines (common power supply lines) 133, the scanning line driving circuit 11 that supplies scanning signals to the scanning lines 131, and the signal line driving circuit 12 that supplies data signals to the signal lines 132. And a common line driving circuit 13 for supplying a positive power source (or a negative power source) having a predetermined potential to the common line 133. A display area 15 is provided in the center of the TFT array substrate 1, and a plurality of pixels 10 are defined in a matrix in the display area 15.

  As shown in FIGS. 1 and 2, each pixel 10 includes a switching TFT 221 as an example of a second thin film transistor, and a TFT as an example of a first thin film transistor that is controlled by the switching TFT 221 to control a current to each pixel (hereinafter referred to as a TFT). , Which is referred to as a current TFT) 223, an organic EL element 224, and a storage capacitor 222 are provided. Further, a pixel electrode 141 made of an ITO (Indium Tin Oxide) film or the like is connected to the drain of the current TFT 223 (see FIG. 2), and an Al (aluminum) film is connected to the pixel electrode 141 via the organic EL element 224. The counter electrode which consists of etc. is opposingly arranged. The counter electrode is grounded, for example, or connected to a negative power source (or positive power source) having a predetermined potential.

  Since it is configured as described above, the light emission operation in one pixel is performed as follows. That is, when a scanning signal is output from the scanning line driving circuit 11 to the scanning line 131 and a data signal is supplied from the signal line driving circuit 12 to the signal line 132, the scanning line 131 corresponds to the scanning line 131 and the signal line 132. The switching TFT 221 in the pixel 10 to be turned on is turned on, and the voltage (Vsig) of the data signal supplied to the signal line 132 is applied to the gate of the current TFT 223. As a result, a drive current (Id) corresponding to the gate voltage flows between the drain and source of the current TFT 223 from the common line drive circuit 13 through the common line 133, and further, the organic EL through the pixel electrode 141 (see FIG. 2). The organic EL element 224 emits light by flowing from the element 224 to the counter electrode. The charge charged in the storage capacitor 222 while the switching TFT 221 is on is discharged after the switching TFT 221 is turned off, and the current flowing through the organic EL element 224 is predetermined even after the switching TFT 221 is turned off. Continue to flow for a period of time.

  In each of the following embodiments, the current-driven light-emitting element that is current-driven in each pixel of the display device is an organic EL element. Instead of this organic EL element, for example, other inorganic electroluminescence (Hereinafter referred to as “inorganic EL element”), LED (light-emitting diode = light-emitting diode), LEP (light-emitting polymer), and other known current-driven light-emitting elements are used to constitute the display device. May be. In addition, the drive element that controls the drive current of each current-driven light emitting element is a current TFT. Instead of this current TFT, other drive elements such as FETs (field effect transistors) and bipolar transistors are used. The display device may be configured. In the case of a current-driven light emitting element or a current-driving drive element, deterioration with time occurs somewhat as the drive current flows, so that the effects of the embodiments described below are exhibited. However, when the display device is configured by using the organic EL element 224 and the current TFT 223 whose deterioration with time is particularly remarkable, the effects of the embodiments described below are effectively exhibited.

  In the basic configuration described above, by adding a circuit and an element for appropriately correcting deterioration with time and variation in characteristics in the organic EL element 224 and the current TFT 223 shown in the following Examples 1 to 13, the display area 15 It is possible to prevent a decrease in screen brightness and occurrence of screen unevenness among the plurality of pixels 10. Each example will be described below.

  FIG. 3 is a block diagram of a display device including the TFT-OELD according to the first embodiment of the present invention. In the present embodiment, the common electrode drive circuit 13 is a circuit that supplies a power signal of a predetermined potential (for example, a positive potential) to the common line 133 (see FIGS. 1 and 2). The counter electrode drive circuit 14 is a circuit that supplies a power supply signal having a predetermined potential (for example, ground potential) to a counter electrode disposed to face the pixel electrode 141 (see FIG. 2) with the organic EL element 224 interposed therebetween.

  In the present embodiment, in particular, in order to correct a decrease in driving current due to deterioration with time of the organic EL element 224 and the current TFT 223 (thus, a decrease in light emission amount of the organic EL element 224), the current amount measuring device 16, the comparison circuit 21a, A voltage control circuit 22a and a controller 23 are provided. At least one of the common electrode drive circuit 13, the counter electrode drive circuit 14, the current amount measuring device 16, the comparison circuit 21a, the voltage control circuit 22a, and the controller 23 is on the TFT array substrate 1 shown in FIG. Or may be configured as an external IC and may be externally attached to the TFT array substrate 1.

  The current amount measuring device 16 measures the drive current that flows from the common electrode drive circuit 13 to the display organic EL element 224 (see FIG. 1) in the display region 15.

  The comparison circuit 21a compares the measured current amount ID measured by the current amount measuring device 16 with a preset reference current amount Iref, and the voltage control circuit 22a compares the difference between the two current amounts based on the comparison result. The output voltage (V com) of the common electrode drive circuit 13 is adjusted so that becomes smaller. That is, feedback is applied to the output voltage (V com) from the common electrode driving circuit 13 so that the measured current amount ID approaches the reference current amount I ref. As a result, if such feedback is not applied, the decrease in the drive current flowing through the organic EL element 224 due to deterioration of the organic EL element 224 and current TFT 223 over time is the output voltage (V com) of the common electrode drive circuit 13. It is corrected by the increase in drive current due to the increase in.

  Such correction operation according to this embodiment will be described with reference to FIG.

  First, a case where correction is not performed as in this embodiment will be described with reference to the upper part of FIG. In this case, when the pixel signal is displayed corresponding to the gradation level D1 of the image signal, when the data signal of the voltage V1 is supplied to the signal line, the common electrode potential, the counter electrode potential, the data in the display device so that the drive current Id1 flows. Assume that the power supply potential of the signal has been initially set. Thereafter, when the organic EL element or the current TFT deteriorates with time, the drive current Id flowing through the organic EL element decreases even if the data signal of the same voltage V1 is supplied (here, the reduced current is expressed as I d1 'And). Therefore, when an image is displayed with the various voltage settings as it is, the brightness (luminance) of the organic EL element that emits light in accordance with the drive current Id decreases.

  Next, the case of performing correction as in this embodiment will be described with reference to the lower part of FIG. In this case, even if the organic EL element 224 and the current TFT 223 are deteriorated with time, the output from the common electrode drive circuit 13 is obtained so that the same drive current I d1 as in the initial state can be obtained for the same gradation level D1. The voltage (V com) is increased. That is, by increasing the output voltage (V com) from the common electrode driving circuit 13, a data signal having a voltage V1 ′ that is higher by ΔV1 than the voltage V1 is supplied to the image signal having the gradation level D1. A drive current I d1 similar to that flows.

  Thus, the drive current Id flowing through the organic EL element 224 is corrected so that the current characteristic with respect to the image signal becomes the same as the initial state by increasing the output voltage (V com) of the common electrode drive circuit 13. is there. Therefore, when the image display is performed after the correction process for the deterioration with time (that is, the adjustment process of the output voltage (V com) of the common electrode driving circuit 13), the organic EL element 224 and the current TFT 223 are significantly deteriorated with time. Even in such a case, a decrease in the brightness (luminance) of the organic EL element 224 can be reduced.

  The correction processing as described above can be performed in real time in parallel with the display operation. However, in view of the progress speed of deterioration over time, it is not necessary to perform the display device 100 all the time during the display operation, and it is sufficient to carry out an appropriate period. Therefore, in this embodiment, the controller 23 performs correction processing for such deterioration with time independently of the normal display operation, for example, when the main power of the display device 100 is turned on or at regular intervals prior to the display period. In the period from one correction process to the next correction process, the output voltage value (V com) of the common electrode drive circuit 13 is fixed to the value corrected (adjusted) last. According to this configuration, it is possible to obtain an advantage that the image quality of the display image is not adversely affected by the correction process and an advantage that the operation speed and the refresh rate in the display device 100 are not reduced.

  Furthermore, in this embodiment, such a voltage control circuit is used while performing image display of a predetermined pattern in the display area 15 such as supplying a data signal for maximally emitting light from all the organic EL elements 224 by the controller 23. It is configured to perform correction processing using 22a or the like. With this configuration, the amount of current can be accurately measured, and the influence of deterioration with time can be corrected accurately.

  As a result of the above, according to the present embodiment, when deterioration with time occurs in which the amount of drive current Id flowing through the organic EL element 224 decreases, the current decrease due to the deterioration with time is accurately corrected, and the screen luminance is improved. It is possible not to cause a decrease.

  In this embodiment, the voltage applied to the common line 133, that is, the voltage applied to the pixel electrode 141 is adjusted in accordance with the measured current amount ID flowing through the measured organic EL element 224. Yes. However, as a modification of the present embodiment, the scanning line 131 and the signal line 132 (the scanning line 131 and the signal line 132 are collectively referred to as “bus wiring”) corresponding to the measured current amount ID thus measured. Alternatively, the voltage applied to the counter electrode (the pixel electrode 141 and the counter electrode are collectively referred to as “electrode”) may be adjusted.

  That is, for example, as shown in FIG. 5, instead of the voltage control circuit 22a shown in FIG. 3, the counter electrode is set so that the measured current amount ID and the reference current amount Iref compared in the comparison circuit 21a match. Even if the voltage control circuit 22b for adjusting the voltage of the drive circuit 14 is provided, the same effect as in the first embodiment can be obtained. However, in this case, it goes without saying that it does not function if the counter electrode is grounded.

  Alternatively, as shown in FIG. 6, in place of the voltage control circuit 22a shown in FIG. 3, the signal line driving circuit is configured so that the measured current amount ID compared with the reference current amount I ref matches in the comparison circuit 21a. Even if the voltage control circuit 22c for adjusting the voltage of 12 is provided, the same effect as in the first embodiment can be obtained.

  Furthermore, in the above-described first embodiment and its modified examples, the predetermined pattern displayed in the display area 15 when performing the correction process (voltage adjustment process by the voltage control circuit 22a or the like) is, for example, all organic as described above. One type of pattern for supplying a data signal for maximally emitting light from the EL element 224 may be used, or a measurement current amount ID for a plurality of patterns is set in advance for each pattern under the control of the controller 23. For example, the voltage control circuit 22a or the like may be configured to perform voltage adjustment so that the sum of the differences between the plurality of patterns is minimized as compared with the reference current amount I ref.

  In particular, in the case of a modification in which the output voltage (that is, the voltage V sig of the data signal) of the signal line driving circuit 12 shown in FIG. 6 is adjusted, a plurality of patterns are measured in this way under the control of the controller 23. By adjusting the voltage V sig of the data signal so that the current amount ID matches the corresponding reference current amount I ref, each voltage (Vn) of the data signal is changed to the drive current Id as shown in FIG. It is possible to individually increase each value I d1, I d2,..., I dn,. That is, when the voltage-current characteristic curve of the drive current Id with respect to the data signal V sig changes in a complicated manner due to deterioration with time such as C1 to C2 (for example, when the change due to deterioration with time is more severe on the low current side than on the high current side or If the correction amount is determined according to the value of each drive current Id in this manner, the drive current Id and the light emission amount in the organic EL element 224 are set for each gradation level of the input image signal. It becomes possible to maintain with high accuracy.

  As described above in detail, according to the present embodiment and its modification, the drive current (measured current amount ID) that actually flows through the organic EL element 224 and the preset reference current (reference current amount I ref) Corresponding to the difference, the voltage applied to the bus wiring or the electrode is adjusted, so that it is possible to correct the deterioration with time in the organic EL element 224 and the current TFT 223.

  FIG. 8 is a block diagram of a display device including a TFT-OELD according to the second embodiment of the present invention. 8, the same components as those in the first embodiment shown in FIG. 3 are denoted by the same reference numerals, and the description thereof is omitted. In this embodiment, a voltage between the common electrode and the counter electrode is applied to the monitoring organic EL element 17a in the current monitoring region 17 provided adjacent to the display region 15, and the display period The organic EL element for monitoring 17a is driven by current under substantially the same conditions as those of the organic EL element 224 (see FIG. 1). When the correction process for the deterioration with time is performed, the current amount measuring device 16 measures the current I dm flowing through the monitoring organic EL element 17a. The comparison circuit 21a, the voltage control circuit 22a, and the controller 23 output the common electrode drive circuit 13 so that the measured current amount ID, which is the measured value of the current I dm by the current amount measuring device 16, matches the reference current amount Iref. It is configured to adjust the voltage (V com). Other configurations are the same as those in the first embodiment.

  Since it is configured as described above, according to the second embodiment, when deterioration with time occurs in which the current amount of the organic EL element 224 and the current TFT 223 (see FIGS. 1 and 2) decreases, the current due to the deterioration with time It is possible to correct the decrease and reduce the decrease in screen brightness in the display area 15.

  In the present embodiment, in particular, the display organic EL element 224 and the monitor EL element 17a are formed on the same TFT array substrate 1 by the same manufacturing process. Accordingly, there is no need to provide a separate process for forming the monitoring organic EL element 17a. In addition, the deterioration with time of the current-driven display organic EL element 224 and the monitor organic EL element 17a can be made similar to each other, and the display-use organic EL element 224 is displayed based on the current I dm flowing through the monitor organic EL element 17a. The organic EL element 224 can be considerably appropriately corrected for deterioration with time.

  In the second embodiment, as in the case of the first embodiment, the correction process for the deterioration with time may be performed, for example, when the main power of the display device 100 is turned on or every certain period prior to the display period, or in real time. You may go on. Further, as a modification, the output voltage in the scanning line driving circuit 11, the signal line driving circuit 12, or the counter electrode driving circuit 14 may be adjusted in accordance with the measured current amount ID thus measured. Good. In particular, in the case of a modification in which the output voltage of the signal line driving circuit 12 is adjusted, the monitor organic EL element 17a is configured to display a plurality of displays with different brightness in the current monitor region 17 under the control of the controller 23. , By adjusting the voltage V sig of the data signal so that the measured current amount ID obtained for each brightness matches the corresponding reference current amount I ref, the current-voltage characteristics due to deterioration over time can be obtained. It is possible to deal with cases where complicated changes occur.

  FIG. 9 is a block diagram of a display device including a TFT-OELD according to Example 3 of the present invention. 9, the same components as those in the first embodiment shown in FIG. 3 are denoted by the same reference numerals, and the description thereof is omitted.

  In this embodiment, instead of the current amount measuring device 16 in the first embodiment, a light emission amount measuring device 18 for measuring the light emission amount of the display organic EL element 224 (see FIG. 1) in the display region 15 is provided. Yes. When correcting the deterioration with time, a scanning signal of a predetermined voltage from the scanning line driving circuit 11, a data signal of a predetermined voltage from the signal line driving circuit 12, and the common electrode driving circuit 13 and the counter electrode driving circuit 14 A power supply signal having a predetermined voltage is applied. The light emission amount measuring device 18 detects the light emitted from the organic EL element 224 that emits light in response thereto. The comparison circuit 21b compares the measured light emission amount LD with a preset reference light emission amount Lref. The output voltage of the common electrode drive circuit 13 is adjusted by the comparison circuit 21b, the voltage control circuit 22a, and the controller 23 so that the light emission amount LD to be compared and the reference light emission amount Lref are matched. ing. Other configurations are the same as those in the first embodiment.

  According to the third embodiment configured as described above, deterioration with time in which the drain current (driving current) amount with respect to the gate voltage in the current TFT 223 (see FIGS. 1 and 2) decreases, and the current amount with respect to the voltage in the organic EL element 224 Degradation over time, degradation over time in which the amount of light emission with respect to the drive current in the organic EL element 224 decreases, and when the amount of light emission in the organic EL element 224 eventually decreases, the amount of decrease in light emission due to the degradation over time. Can be corrected by increasing the voltage applied to the organic EL element 224 to prevent the screen luminance in the display area 15 from being lowered.

  Also in the third embodiment, as in the first embodiment, the correction for the deterioration with time may be performed, for example, when the main power of the display device 100 is turned on or every certain period prior to the display period, or in real time. You may go. Furthermore, as a modification, the output voltage in the scanning line driving circuit 11, the signal line driving circuit 12, or the counter electrode driving circuit 14 may be adjusted in accordance with the measured light emission amount LD thus measured. Alternatively, the predetermined pattern for correcting the deterioration with time may be one type or a plurality of types. In particular, in the modification in which the output voltage of the signal line drive circuit 12 is adjusted, under the control of the controller 23, the measured light emission amount LD is made to coincide with the corresponding reference light emission amount L ref for a plurality of predetermined patterns. By adjusting the voltage Vsig of the data signal, it is possible to cope with a complicated change in current-voltage characteristics due to deterioration with time.

  FIG. 10 is a block diagram of a display device including a TFT-OELD according to Embodiment 4 of the present invention. 10, the same components as those of the first and third embodiments shown in FIGS. 3 and 9 are given the same reference numerals, and the description thereof is omitted.

  In this embodiment, a voltage between the common electrode and the counter electrode is applied to the monitor organic EL element 19a in the light emission monitor region 19 provided adjacent to the display region 15, and the display period The organic EL element for monitoring 19a is driven by current under substantially the same conditions as those of the organic EL element 224 (see FIG. 1). Then, when correcting the deterioration with time, the light emission amount measuring device 18 measures the light emission of the monitoring organic EL element 19a. The comparison circuit 21b, the voltage control circuit 22a, and the controller 23 output the output voltage of the common electrode drive circuit 13 so that the measured light emission amount LD, which is a measurement value of light emission by the light emission amount measuring device 18, matches the reference light emission amount Lref. Configured to adjust. Other configurations are the same as those in the first and third embodiments.

  According to the fourth embodiment configured as described above, in the same manner as in the third embodiment, the current TFT 223 (refer to FIGS. 1 and 2) and the organic EL element 224 are deteriorated over time due to deterioration in the amount of current with respect to the voltage. When deterioration of the light emission amount with respect to the driving current in the EL element 224 is deteriorated with time, and the light emission amount in the organic EL element 224 is finally reduced, the decrease in the light emission amount is corrected, and the screen luminance in the display region 15 is corrected. Can be prevented.

  Also in the fourth embodiment, as in the first embodiment, the correction for the deterioration with time may be performed, for example, when the main power of the display device 100 is turned on or every certain period prior to the display period, or in real time. You may go. Furthermore, as a modification, the output voltage in the scanning line driving circuit 11, the signal line driving circuit 12, or the counter electrode driving circuit 14 may be adjusted in accordance with the measured light emission amount LD thus measured. Alternatively, the predetermined pattern for correcting the deterioration with time may be one type or a plurality of types. In particular, in the modification in which the output voltage of the signal line drive circuit 12 is adjusted, under the control of the controller 23, the measured light emission amount LD is made to coincide with the corresponding reference light emission amount L ref for a plurality of predetermined patterns. By adjusting the voltage Vsig of the data signal, it is possible to cope with a complicated change in current-voltage characteristics due to deterioration with time. In the present embodiment, in particular, the display organic EL element 224 and the monitor organic EL element 19a are formed on the same TFT array substrate 1 by the same manufacturing process. Accordingly, there is no need to provide a separate process for forming the monitor EL element 19a. Moreover, the tendency of deterioration with time in the current-driven display organic EL element 224 and the monitor organic EL element 19a can be made similar, and the display is based on the light emitted from the monitor EL element 19a. It is possible to accurately correct the deterioration with time in the organic EL element 224.

  In the fifth to tenth embodiments described below, unlike the above-described first to fourth embodiments, the drive current amount decreases due to deterioration over time in the organic EL element 224 and the current TFT 223 generated in units of each pixel. Alternatively, the present invention relates to a pixel circuit that corrects a decrease in light emission amount of the organic EL element 224 in units of pixels.

  In the following fifth to tenth embodiments, the configuration of a display device including a plurality of pixel circuits for each pixel is the same as that shown in FIG. FIG. 11 is an equivalent circuit diagram of a pixel circuit including the TFT-OELD according to the fifth embodiment of the present invention. In FIG. 11, the same components as those shown in the circuit diagram of each pixel 10 in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.

  In FIG. 11, in the pixel circuit according to the present embodiment, depending on the relationship between the voltage across the organic EL element 224 and the amount of the drive current Id flowing through the organic EL element 224, the distance between the first power supply line 213 and the second power supply line. The resistance of 215 is changed. Here, the first power supply line 213 is a common line portion in each pixel connected to the pixel electrode to which a power signal having a predetermined potential is supplied from the common line driving circuit. On the other hand, the second inter-feed line 215 is a feed line portion in each pixel connected to the counter electrode to which a power signal having a predetermined potential is supplied from the counter electrode drive circuit.

  More specifically, the potential of the first power supply line (common electrode) 213 is higher than that of the second power supply line (counter electrode) 215 (that is, positive power is supplied to the common electrode and negative voltage is applied to the counter electrode). When the power is supplied), as shown in FIG. 11, the n-channel first correction TFT 231 has its gate electrode connected to the electrode on the first feeder line side of the organic EL element 224, A source electrode and a drain electrode are added so as to be connected in series with the organic EL element 224 between the organic EL element 224 and the second feeder line 215. According to this configuration, when the resistance of the organic EL element 224 increases, the gate voltage of the first correction TFT 231 increases and the resistance between the source electrode and the drain electrode decreases. Therefore, according to the fifth embodiment, even if the resistance of the organic EL element 224 increases due to deterioration over time, the driving current due to the increase in resistance in the organic EL element 224 is decreased due to the decrease in resistance between the source and drain of the first correction TFT 231. It is possible to correct a decrease in the current amount of Id and reduce a decrease in screen luminance. In addition, since such correction is performed on a pixel-by-pixel basis, when deterioration with time occurs with a variation between a plurality of pixels, or when there is a variation in current-voltage characteristics between a plurality of pixels in the initial state, It is possible to prevent unevenness.

  As a modification of the fifth embodiment, the potential of the first power supply line 213 is lower than that of the second power supply line 215 (that is, a negative power supply is supplied to the common electrode and a positive power supply is supplied to the counter electrode. The first correction TFT 231 is a p-channel type, the gate electrode thereof is connected to the electrode on the first feeder line side of the organic EL element 224, and the source electrode and the drain electrode are connected to the organic EL element 224 and the first What is necessary is just to comprise so that it may connect in series with the organic EL element 224 between the 2 electric power feeding lines 215. According to this configuration, when the resistance of the organic EL element 224 increases, the gate voltage of the first correction TFT 231 decreases, the resistance between the source electrode and the drain electrode decreases, and correction is automatically performed. In the present embodiment, the switching TFT 221, the current TFT 223, and the first correction TFT 231 are preferably formed on the same TFT array substrate by the same manufacturing process. According to this configuration, it is possible to correct the decrease in the drive current Id due to deterioration with time for each pixel without increasing the number of manufacturing steps.

  FIG. 12 is an equivalent circuit diagram of a pixel circuit including a TFT-OELD according to Example 6 of the present invention. In FIG. 12, the same components as those shown in FIGS. 1 and 11 are denoted by the same reference numerals, and the description thereof is omitted.

  In FIG. 12, in the pixel circuit of this embodiment, depending on the relationship between the voltage at both ends of the organic EL element 224 and the amount of the drive current Id flowing through the organic EL element 224, the distance between the first feed line 213 and the second feed line is determined. The resistance of 215 is changed.

  More specifically, when the potential of the first power supply line 213 is higher than that of the second power supply line 215, as shown in FIG. The gate electrode is connected to the electrode on the second feeding line side of the organic EL element 221, and the source electrode and the drain electrode are added so as to be connected in series with the organic EL element 224 between the organic EL element 224 and the first feeding line. The According to this configuration, when the resistance of the organic EL element 224 increases, the gate voltage of the second correction TFT 232 decreases, and the resistance between the source electrode and the drain electrode decreases.

  Therefore, according to the sixth embodiment, even if the resistance of the organic EL element 224 increases due to deterioration with time, the driving current due to the increase in resistance in the organic EL element 224 is reduced due to the decrease in resistance between the source and drain of the second correction TFT 232. It is possible to correct a decrease in the current amount of Id and reduce a decrease in screen luminance. In addition, since such correction is performed on a pixel-by-pixel basis, when deterioration with time occurs with a variation between a plurality of pixels, or when there is a variation in current-voltage characteristics between a plurality of pixels in the initial state, It is possible to prevent unevenness.

  As a modification of the sixth embodiment, when the potential of the first power supply line 213 is lower than that of the second power supply line 215, the second correction TFT 232 is an n-channel TFT and the gate electrode thereof is The organic EL element 224 may be connected to the electrode on the second feeder line side, and the source electrode and the drain electrode may be connected in series with the organic EL element 224 between the organic EL element 224 and the first feeder line. According to this configuration, when the resistance of the organic EL element 224 increases, the gate voltage of the second correction TFT 232 increases, the resistance between the source electrode and the drain electrode decreases, and correction is automatically performed.

  In this embodiment, the switching TFT 221, the current TFT 223, and the second correction TFT 232 are preferably formed on the same TFT array substrate by the same manufacturing process. According to this configuration, it is possible to correct the decrease in the drive current Id due to deterioration with time for each pixel without increasing the number of manufacturing steps.

  FIG. 13 is an equivalent circuit diagram of a pixel circuit including a TFT-OELD according to Example 7 of the present invention. In FIG. 13, the same components as those shown in FIGS. 1 and 11 are denoted by the same reference numerals, and the description thereof is omitted.

In FIG. 13, in the pixel circuit of the present embodiment, depending on the relationship between the voltage at both ends of the organic EL element 224 and the amount of drive current Id flowing therethrough, between the storage capacitor 222 and the first power supply line 213. Change the resistance.
More specifically, when the potential of the first power supply line 213 is higher than that of the second power supply line 215, as shown in FIG. The TFT 233 is added so that the gate electrode is connected to the electrode on the first power supply line side of the organic EL element 224 and the source electrode and the drain electrode are connected between the storage capacitor 222 and the first power supply line 213. According to this configuration, when the resistance of the organic EL element 224 increases, the gate voltage of the third correction TFT 233 increases and the resistance between the source electrode and the drain electrode decreases. For this reason, the gate voltage of the current TFT 223 increases, and the resistance between the source electrode and the drain electrode decreases.

  Therefore, according to Example 7, even if the resistance of the organic EL element 224 increases due to deterioration over time, the driving current due to the increase in resistance in the organic EL element 224 is reduced due to the decrease in resistance between the source and drain of the third correction TFT 233. It is possible to correct a decrease in the current amount of Id and reduce a decrease in screen luminance. In addition, since such correction is performed on a pixel-by-pixel basis, when deterioration with time occurs with a variation between a plurality of pixels, or when there is a variation in current-voltage characteristics between a plurality of pixels in the initial state, It is possible to prevent unevenness.

  As a modification of the seventh embodiment, when the potential of the first feeder 213 is higher than that of the second feeder, the current TFT 223 is a p-channel type and the third correction TFT 233 is a p-channel type. In addition, the gate electrode may be connected to the electrode on the first power supply line side of the organic EL element 224, and the source electrode and the drain electrode may be connected between the storage capacitor 222 and the first power supply line 213. According to this configuration, when the resistance of the organic EL element 224 increases, the gate voltage of the third correction TFT 233 increases and the resistance between the source electrode and the drain electrode increases. For this reason, the gate voltage of the rent TFT 223 decreases, the resistance between the source electrode and the drain electrode decreases, and correction is automatically performed.

  As another modification of the seventh embodiment, when the potential of the first power supply line 213 is lower than that of the second power supply line 215, the current TFT 223 is an n-channel type, and the third correction TFT 233 is The gate electrode is connected to the electrode on the first power supply line side of the organic EL element 224, and the source electrode and the drain electrode are connected between the storage capacitor 222 and the first power supply line 213. Also good. According to this configuration, when the resistance of the organic EL element 224 increases, the gate voltage of the third correction TFT 233 decreases and the resistance between the source electrode and the drain electrode increases. For this reason, the gate voltage of the current TFT 223 increases, the resistance between the source electrode and the drain electrode decreases, and correction is automatically performed.

  As another modification of the seventh embodiment, when the potential of the first power supply line 213 is lower than that of the second power supply line 215, the current TFT 223 is a p-channel type, and the third correction TFT 233 is p The gate electrode may be connected to the electrode on the first power supply line side of the organic EL element 224, and the source electrode and the drain electrode may be connected between the storage capacitor 222 and the first power supply line 213. Good. According to this configuration, when the resistance of the organic EL element 224 increases, the gate voltage of the third correction TFT 233 decreases, and the resistance between the source electrode and the drain electrode decreases. For this reason, the gate voltage of the current TFT 223 decreases, the resistance between the source electrode and the drain electrode decreases, and correction is automatically performed.

  In this embodiment, the switching TFT 221, the current TFT 223, and the third correction TFT 233 are preferably formed on the same TFT array substrate by the same manufacturing process. According to this configuration, it is possible to correct the decrease in the drive current Id due to deterioration with time for each pixel without increasing the number of manufacturing steps.

  FIG. 14 is an equivalent circuit diagram of a pixel circuit including a TFT-OELD according to the eighth embodiment of the present invention. In FIG. 14, the same components as those shown in FIGS. 1 and 11 are denoted by the same reference numerals, and the description thereof is omitted.

  In FIG. 14, in the pixel circuit of the present embodiment, depending on the relationship between the voltage across the organic EL element 224 and the amount of the drive current Id flowing therethrough, the voltage between the storage capacitor 222 and the second feed line 215 Change the resistance.

  More specifically, when the potential of the first power supply line 213 is higher than that of the second power supply line 215, as shown in FIG. The fourth correction TFT 234 has a gate electrode connected to the electrode on the first power supply line side of the organic EL element 224 and a source electrode and a drain electrode connected between the storage capacitor 222 and the second power supply line 215. It has been added. According to this configuration, when the resistance of the organic EL element 224 increases, the gate voltage of the fourth correction TFT 234 increases, and the resistance between the source electrode and the drain electrode increases. For this reason, the gate voltage of the current TFT 223 increases, and the resistance between the source electrode and the drain electrode decreases.

  Therefore, according to the eighth embodiment, even if the resistance of the organic EL element 224 increases due to deterioration with time, the drive current due to the increase in resistance in the organic EL element 224 due to the increase in resistance between the source and drain of the fourth correction TFT 234. It is possible to correct a decrease in the current amount of Id and reduce a decrease in screen luminance. In addition, since such correction is performed on a pixel-by-pixel basis, when deterioration with time occurs with a variation between a plurality of pixels, or when there is a variation in current-voltage characteristics between a plurality of pixels in the initial state, It is possible to prevent unevenness.

  As a modification of the eighth embodiment, when the potential of the first feeder 213 is higher than the second feeder 215, the current TFT 223 is a p-channel type and the fourth correction TFT is an n-channel. The gate electrode may be connected to the electrode on the first feeder line side of the organic EL element 224, and the source electrode and the drain electrode may be connected between the storage capacitor 222 and the second feeder line 215. . According to this configuration, when the resistance of the organic EL element 224 increases, the gate voltage of the fourth correction TFT 234 increases and the resistance between the source electrode and the drain electrode decreases. For this reason, the gate voltage of the current TFT 223 decreases, the resistance between the source electrode and the drain electrode decreases, and correction is automatically performed.

  As another modification of the eighth embodiment, when the potential of the first power supply line 213 is lower than that of the second power supply line 215, the fourth correction TFT is compared with the n-channel current TFT 223. P channel type, the gate electrode is connected to the electrode on the first feeder line side of the organic EL element 224, and the source electrode and drain electrode are connected between the storage capacitor 222 and the second feeder line 215. Also good. According to this configuration, when the resistance of the organic EL element 224 increases, the gate voltage of the fourth correction TFT 234 decreases and the resistance between the source electrode and the drain electrode decreases. For this reason, the gate voltage of the current TFT 223 increases, the resistance between the source electrode and the drain electrode decreases, and correction is automatically performed.

  Furthermore, as another modification of the eighth embodiment, when the potential of the first power supply line 213 is lower than that of the second power supply line 215, the current TFT 223 is a p-channel type, and the fourth correction TFT 234 is The gate electrode is connected to the electrode on the first power supply line side of the organic EL element 224, and the source electrode and the drain electrode are connected between the storage capacitor 222 and the second power supply line 215. Also good. According to this configuration, when the resistance of the organic EL element 224 increases, the gate voltage of the fourth correction TFT 234 decreases and the resistance between the source electrode and the drain electrode increases. For this reason, the gate voltage of the current TFT 223 decreases, the resistance between the source electrode and the drain electrode decreases, and correction is automatically performed.

  In the present embodiment, the switching TFT 221, the current TFT 223, and the fourth correction TFT 234 are preferably formed on the same TFT array substrate by the same manufacturing process. According to this configuration, it is possible to correct the decrease in the drive current Id due to deterioration with time for each pixel without increasing the number of manufacturing steps.

  FIG. 15 is an equivalent circuit diagram of a pixel circuit including a TFT-OELD according to the ninth embodiment of the present invention. In FIG. 15, the same components as those shown in FIGS. 1 and 11 are denoted by the same reference numerals, and the description thereof is omitted.

  In FIG. 15, the first correction thin film photodiode 241 provided in the pixel circuit of this embodiment has a property of becoming low resistance when irradiated with light.

  In this embodiment, the resistance between the storage capacitor 222 and the first power supply line 213 is changed depending on the relationship between the voltage at both ends of the organic EL element 224 and the light emission amount.

  More specifically, when the potential of the first power supply line 213 is higher than that of the second power supply line 215, the first correction is performed on the p-channel current TFT 223 as shown in FIG. The thin film photodiode 241 is connected between the storage capacitor 222 and the first power supply line 213. According to this configuration, when the light emission of the organic EL element 224 decreases, the resistance of the first correction thin film photodiode 241 increases. For this reason, the gate voltage of the current TFT 223 decreases, and the resistance between the source electrode and the drain electrode decreases.

  Therefore, according to Example 9, even if the light emission amount of the organic EL element 224 decreases due to deterioration over time, the decrease in the light emission amount in the organic EL element 224 is corrected by the increase in resistance of the first correction thin film photodiode 241. It becomes possible. In addition, since such correction is performed on a pixel-by-pixel basis, when deterioration with time occurs with a variation between a plurality of pixels, or when there is a variation in light emission characteristics between a plurality of organic EL elements in the initial state, It is possible to prevent screen unevenness.

  As a modification of the ninth embodiment, a fifth correction TFT (not shown) may be provided so that its source electrode and drain electrode are connected between the storage capacitor 222 and the first power supply line 213. .

  As another modification of the ninth embodiment, when the potential of the first power supply line 213 is lower than that of the second power supply line 215, the current TFT 223 is an n-channel type, and the first correction thin film photo The diode 241 may be configured to be connected between the storage capacitor 222 and the first power supply line 213. In this case, a fifth correction TFT (not shown) may be provided so that the source electrode and the drain electrode are connected between the storage capacitor and the first power supply line. According to this configuration, when the light emission amount of the organic EL element 224 is decreased, the resistance of the first correction thin film photodiode 241 is increased, and the gate voltage of the current TFT 223 is further increased so that the source electrode is connected to the drain electrode. The resistance decreases and correction is automatically performed.

  In the present embodiment, the switching TFT 221, the current TFT 223, and the first correction thin film photodiode 241 are preferably formed on the same TFT array substrate by the same manufacturing process. According to this configuration, it is possible to correct the decrease in the drive current Id due to deterioration with time for each pixel without increasing the number of manufacturing steps.

  FIG. 16 is an equivalent circuit diagram of a pixel circuit including a TFT-OELD according to Example 10 of the present invention. In FIG. 16, the same components as those shown in FIGS. 1 and 11 are denoted by the same reference numerals, and the description thereof is omitted.

  In FIG. 16, the second thin film photodiode for correction 242 provided in the pixel circuit of this embodiment has a property of becoming low resistance when irradiated with light.

In this embodiment, the resistance between the storage capacitor 222 and the second power supply line 215 is changed depending on the relationship between the voltage across the organic EL element 224 and the light emission amount.
More specifically, when the potential of the first power supply line 213 is higher than that of the second power supply line 215, the second correction is performed on the n-channel current TFT 223 as shown in FIG. A thin film photodiode 242 is connected between the storage capacitor 222 and the second power supply line 215. According to this configuration, when the light emission amount of the organic EL element 224 decreases, the resistance of the second correction thin film photodiode 242 increases. For this reason, the gate voltage of the current TFT 223 is increased, and the resistance between the source electrode and the drain electrode is decreased.

  Therefore, according to Example 10, even if the light emission amount of the organic EL element 224 decreases due to deterioration with time, the light emission amount decrease in the organic EL element 224 is corrected by the increase in resistance of the second correction thin film photodiode 242. It becomes possible. In addition, since such correction is performed on a pixel-by-pixel basis, when deterioration with time occurs with a variation between a plurality of pixels, or when there is a variation in light emission characteristics between a plurality of organic EL elements in the initial state, It is possible to prevent screen unevenness.

  As a modification of the tenth embodiment, a sixth correction TFT (not shown) may be provided such that the source electrode and the drain electrode are connected between the storage capacitor and the second feeder line 215. .

  As another modification of the tenth embodiment, when the potential of the first power supply line 213 is lower than that of the second power supply line 215, the current TFT 223 is a p-channel type, and the second correction thin film photo The diode 242 may be configured to be connected between the storage capacitor 222 and the second feeder line 215. In this case, a sixth correction TFT (not shown) may be provided so that the source electrode and the drain electrode are connected between the storage capacitor 222 and the second power supply line 215. According to this configuration, when the light emission amount of the organic EL element 224 is decreased, the resistance of the second correction thin film photodiode 242 is increased, and the gate voltage of the current TFT 223 is further decreased, so that the current between the source electrode and the drain electrode is decreased. The resistance decreases and correction is automatically performed.

  In this embodiment, the switching TFT 221, the current TFT 223, and the second correction thin film photodiode 242 are preferably formed on the same TFT array substrate by the same manufacturing process. According to this configuration, it is possible to correct the decrease in the drive current Id due to deterioration with time for each pixel without increasing the number of manufacturing steps.

  Next, an eleventh embodiment of the present invention will be described with reference to FIGS.

  FIG. 17 is a block diagram of a display device including the TFT-OELD according to the eleventh embodiment, and FIG. 18 is a block diagram of a common line driving circuit 13 ′ included in the display device. In FIG. 17, a pixel circuit for only one pixel is illustrated in the display region 115, but actually a similar pixel circuit is provided for each pixel.

  In FIG. 17, the display device 200 a according to the present embodiment includes a common line configured to be able to separately supply a power signal to each of the plurality of common lines 133 in addition to the scanning line driving circuit 11 and the signal line driving circuit 12. A drive circuit 13 ′, a common line power supply 205 that supplies power to the common line drive circuit 13 ′, and a measured current amount IDmn (m) for each of the plurality of pixels 10 in the display region 15 measured by the current measurement circuit 16 ′. : A signal line number (1 to M), n: a signal line number (1 to N)), and a deterioration correction circuit interposed between the image signal source 208 and the signal line drive circuit 12. 209. The deterioration correction circuit 209 stores the gradation (luminance) level of the image signal input from the image signal source 208 in the frame memory 207 in order to correct a decrease in the amount of drive current Id due to deterioration over time in each of the plurality of pixels 10. The correction is made for each pixel 10 in accordance with each measured current amount IDn, and then output to the signal line drive circuit 12. At least one of the common line drive circuit 13 ′, the common line power supply 205, the current measurement circuit 16 ′, the frame memory 207, and the deterioration correction circuit 209 is formed on the TFT array substrate soil provided with the display region 115 in the center. Alternatively, it may be configured as an external IC and externally attached to the TFT array substrate.

  In FIG. 17, the common line driving circuit 13 ′ includes a changeover switch 301, a shift register 302, and a transmission switch 303. In the normal display operation, the changeover switch 301 is supplied with a power signal having a predetermined potential all at once to the plurality of common lines 133 via the wiring 310 (that is, the potentials of all the common lines 133 are equalized). As shown in FIG. 5, switching to the power supply wiring 310 connected to the common line power supply 205 is performed under the control of the controller. On the other hand, when the change-over switch 301 performs correction for deterioration with time as described later (adjustment of the voltage of the power supply signal supplied to each common line 133), the power supply signal for measurement is supplied to the plurality of common lines 133 via the wiring 320. Are switched to the wiring 320 side connected to the current amount measuring circuit 16 ′ via the transmission switch 303. The measurement power supply signal may be supplied from the power supply built in the current measurement circuit 16 ′ via the wiring 320, or may be supplied via the wiring 320 using the power supply of the common line power supply 205. .

  The transmission switch 303 transmits the measurement power signal to the changeover switch 301 according to the transfer signal sequentially output from the shift register 302 when correcting the deterioration with time, and the changeover switch 301 transmits this via the common line 133. To each pixel circuit. At this time, the shift register 302 is configured to sequentially output a transfer signal corresponding to each of the plurality of common lines 133 under the control of a controller (not shown).

  Next, the operation of the present embodiment configured as described above will be described.

  First, when correction for deterioration with time is performed, a power supply for measurement is sequentially applied to a plurality of common lines 133 via each transmission switch 303 that can be transmitted according to transfer signals sequentially output from the shift register 302. A signal is supplied. Then, the current amount of the power supply signal for measurement is measured for each common line 133. Here, since the scanning signal is sequentially supplied to each pixel 10 from the scanning line driving circuit 11, each pixel to which the scanning signal is supplied out of the pixel column in which the power supply signal is supplied from one common line 133. A power signal for measurement flows as a drive current to the organic EL element 224 via the current TFT 223. That is, by sequentially supplying the scanning power supply signal to the common line 133 at the timing of the transfer signal by the shift register 302 while sequentially supplying the scanning signal from the scanning line driving circuit 11, the driving current Id for each pixel 10 is obtained as a current. Measurement is performed in a point-sequential manner by the quantity measuring circuit 16 '. The measured current amount IDmn is stored in the frame memory 207.

  Next, when performing a normal display operation, the image signal from the image signal source 208 is sent to the deterioration correction circuit 209. The deterioration correction circuit 209 determines the current due to the deterioration over time according to the degree of deterioration over time determined based on the current amount IDmn of each pixel 10 stored in the frame memory 207 (that is, the degree of decrease in the measured drive current amount with respect to the reference current amount). The gradation level of the image signal is corrected for each pixel 10 so as to correct the decrease, and is output to the signal line driving circuit 12. As a result, the change in the light emission amount of the organic EL element 224 in each pixel 10 is corrected by the gradation level change by the deterioration correction circuit 209. When a normal display operation is performed, the changeover switch 301 of the common line driving circuit 203 is switched to the common line power supply 205 side, and a predetermined potential is supplied to the common line 103.

  In this embodiment, the current amount is separately measured for all the pixels 10 and the measured value IDmn is stored in the frame memory 207. However, for some of the extracted pixels 10, Alternatively, the current amount may be measured for a group of pixel blocks, and the measured value may be stored. In this embodiment, different correction amounts are applied to all the pixels 10. However, correction may be performed on a group of pixel blocks or the entire panel after appropriate processing.

  In this embodiment, each TFT in each drive circuit and each TFT in the pixel circuit are, for example, polycrystalline silicon TFTs formed by a low-temperature process of 600 ° C. or less, and each organic EL element 224 has, for example, Formed by an inkjet process.

  Next, a twelfth embodiment of the present invention will be described with reference to FIGS.

  FIG. 19 is a block diagram of a display device including a TFT-OELD according to Example 12, and FIG. 20 is a cross-sectional view of a pixel circuit included in each pixel of the display device. In FIG. 19, a circuit for only one pixel is illustrated in the display area 115, but actually a similar circuit is provided for each pixel. In FIG. 19, the same reference numerals are given to the same components as those in the embodiment 11 shown in FIG. 17, and the description thereof is omitted.

  In FIG. 19, the display device 200b of the present embodiment includes a scanning line driving circuit 11, a signal line driving circuit 12, a common line power supply 205 that supplies a power signal of a predetermined potential to the common line 133, and a current measurement circuit 16 ''. The frame memory 207 and the degradation correction circuit 209. The display device 200b includes, in particular, a PIN diode 110 as an example of a light emission amount measuring semiconductor element having one end connected to the common line 133 for each pixel circuit. The other end of each PIN diode 110 is provided with an inspection light beam 104 for passing a measurement current to the PIN diode 110 in parallel with the signal line 132 and the common line 133. Then, the display device 200b. Further includes a light detection drive circuit 204 that drives the PIN diode 110 in each pixel via each light analysis 104, and Teikairo 16 ", the measuring current flowing through the PIN diode 110 to be driven is configured to measure for each pixel 10 by test light driving circuit 204. Note that at least one of the light detection drive circuit 204, the common line power supply 205, the current measurement circuit 16 ″, the frame memory 207, and the deterioration correction circuit 209 is formed on a TFT array substrate provided with a display region 115 in the center. (Refer to FIG. 1) Alternatively, it may be configured as an external IC and externally attached to the TFT array substrate, and another example of a semiconductor element for measuring the amount of light emitted instead of the PIN diode 110 may be used. A field effect transistor in which a photoexcitation current flows when light enters the channel portion can be given.

  As shown in FIG. 20, in this embodiment, in each pixel 10, the PIN diode 110 is formed on the TFT array substrate 1 using the same film as the semiconductor film used to form the switching TFT 221 and the current TFT 223. It has a PIN junction formed by impurity doping. Then, a reverse bias voltage is applied to the PIN junction via the light analysis 104 so that a photoexcitation current flows when light enters the PIN junction from the organic EL element 224 via the interlayer insulating films 251 to 253. It is comprised so that it may be supplied from. Further, the gate of each TFT and the scanning line 131 are made of a metal film such as Ta or a low resistance polysilicon film, and the signal line 132, the common line 133, and the light beam 104 are made of a low resistance metal film such as Al. It is configured. A drive current is configured to flow from the pixel electrode 141 made of ITO or the like to the counter electrode 105 (upper electrode) via the current TFT 223 via the EL element 224. If the counter electrode 105 is made of a transparent material such as ITO, the upper surface in FIG. 20 of the display device 200a can be used as the display surface. On the other hand, if the counter electrode 105 is made of a light reflective or light shielding metal material such as Al, the lower surface in FIG. 20 of the display device 200a can be used as the display surface. Here, it is assumed that the counter electrode 105 is mainly composed of Al.

  Next, the operation of the present embodiment configured as described above will be described.

  First, when performing correction processing for deterioration with time, the organic EL element 224 is caused to emit light by supplying a scanning signal and a data signal for displaying a predetermined pattern from the scanning line driving circuit 11 and the signal line driving circuit 12. . Then, since the counter electrode 105 is a material mainly made of Al, light is reflected and emitted downward through the pixel electrode 141. At this time, since the PIN diode 110 reversely biased by the analyzing light 104 is arranged in a part of the optical path, a photoexcitation current is generated in the PIN diode 110 and reaches the detecting drive circuit 204 through the analyzing light 104. . Similar to the common line driving circuit 203 in the eleventh embodiment, the light inspection driving circuit 204 includes a plurality of transmission switches, and sequentially supplies reverse bias power to the PIN diode 110 from the light inspection 204 to the PIN diode 110 for measurement. The measurement current is sequentially supplied to the current measurement circuit 16 ″. Then, as in the case of the eleventh embodiment, the current measurement circuit 16 ″ measures such measurement current for each pixel 10 in a dot-sequential manner. Note that the light emission amount of the organic EL element 224 provided in each pixel 10 substantially increases as the measurement current amount IDmn ′ of the measurement current increases. The storage by the frame memory 207 corresponding to the measured current amount IDmn ′ (measured light emission amount) and the correction by the deterioration correction circuit 209 are also performed in the same manner as in the eleventh embodiment.

  More specifically, as shown in FIG. 21, the deterioration correction method according to the eleventh embodiment is performed.

  That is, in the initial state, as shown in FIG. 21A, since the deterioration correction circuit 209 does not perform correction, the gradation levels D1, D2,... The signal line driving circuit 12 outputs data signals having signal levels V1, V2,. This data signal is applied from the signal line driving circuit 12 to the gate electrode of the current TFT 223 through the signal line 132, the switching TFT 221 and the storage capacitor 222. As a result, the organic EL element 224 emits light levels L1, L2,... Corresponding to the light emission characteristic curve 405 showing the relationship between the potential applied to the gate electrode of the current TFT 223 and the light emission amount of the organic EL element 224. V6 emission is obtained. Here, it is considered that the organic EL element 224 starts to emit light after the signal level Vb exceeds a certain threshold voltage.

Next, when the organic EL element 224 and the current TFT 223 are deteriorated and the light emission amount is changed, the light emission characteristic curve 405 changes as shown in FIG. The light emission characteristic curve 405 is obtained by measuring the light emission amount using the light inspection drive circuit 204, the current measurement circuit 16 ″, etc. in the correction processing described above. The deterioration correction circuit 209 is based on the light emission characteristic curve 405. Then, an appropriate signal conversion curve 404 is set.After that, in the normal display period, the signal level is applied to the gradation levels D1, D2,. Each gradation level is adjusted so that the image signals V1, V2,..., V6 are output from the signal line drive circuit 12. Therefore, in each pixel 10, before the deterioration, according to the light emission characteristic curve 405 after deterioration. In this embodiment, the deterioration of the threshold voltage with respect to the light emission of the organic EL element 224 is also taken into consideration.

  As described above, according to the twelfth embodiment, the light emission amount of the organic EL element 224 in each pixel 10 is measured using the PIN diode 110. Therefore, the deterioration is caused more than in the case of the eleventh embodiment in which the drive current amount is measured. It becomes possible to correct the decrease in the amount of light emission more accurately.

  In this embodiment, the light emission amount is measured for all the pixels 10 and the measured values are stored in the frame memory 207. However, for some of the extracted pixels 10 or a group of pixel blocks The amount of luminescence may be measured and the measured value may be stored. In addition, here, different correction amounts are applied to all the pixels 10, but correction may be performed on a group of pixel blocks or the entire panel after appropriate processing.

  In this embodiment, the PIN diode 110 is used as the light-receiving element for monitoring that generates the photoexcitation current. However, a semiconductor element such as a field effect transistor may be used. At this time, as a potential applied to the gate electrode of the field effect transistor, a potential that effectively generates a photoexcitation current is selected. Furthermore, in order for the light emitted from the organic EL element 224 to reach the channel, a suitable configuration is used such as a top gate type, a positive stagger type, a reverse stagger type, a channel etch type, or a channel stopper type, and the gate electrode is also made of ITO. May be formed. Furthermore, in this embodiment, it is preferable that the TFT formed in each drive circuit or each pixel circuit and the PIN diode as a semiconductor element that generates a photoexcitation current are formed in the same process. This is advantageous because it is not necessary to provide a separate process for forming the PIN diode.

  FIG. 22 shows a deterioration correction method in a display device including the TFT-OELD according to the thirteenth embodiment of the present invention. Since the hardware configuration of the display device of the thirteenth embodiment is the same as that of the eleventh or twelfth embodiment, the description thereof is omitted.

  In the thirteenth embodiment, the method of setting the signal conversion curve 404 based on the light emission characteristic curve 405 obtained by the light emission amount measurement in the deterioration correction circuit 209 described with reference to FIG. In the thirteenth embodiment, the voltage value of the data signal is adjusted by converting from one predetermined signal level to another predetermined signal level. That is, in FIG. 21B corresponding to the case where the organic EL element 224 deteriorates and the light emission amount decreases, the signal levels V1, V2,... The signal conversion curve 404 for the light emission characteristic curve 405 is set by selecting from among the discretized potentials determined in advance due to restrictions such as the power source. As a result, the linearity of the light emission amount is impaired, but tone reversal has not occurred, so that a good tone property can be obtained with the naked eye.

  As described above, according to the thirteenth embodiment, in the signal line driving circuit 12, it is possible to correct a decrease in the amount of light emission due to deterioration with the lapse of time using a power supply of a limited type of potential.

  In the first to thirteenth embodiments, the switching TFT is provided to configure the pixel circuit. For example, the scanning signal is directly supplied to the gate of the driving TFT from the scanning line and the data signal is supplied to the driving TFT. By directly supplying the signal from the signal line to the source, the data signal may be supplied to the organic EL element via the source and drain of the driving TFT to drive the organic EL element. That is, also in this case, it is possible to correct the decrease in the driving current and the light emission amount due to the deterioration with time in the organic EL element and the driving TFT provided in each pixel according to the present invention. Further, the switching TFT provided in each pixel circuit may be composed of an n-channel TFT or a p-channel TFT as long as the voltage polarity of the scanning signal marked on the gate is matched. Also good.

(Electronics)
Next, an embodiment of an electronic apparatus provided with the display device described in detail in each embodiment will be described with reference to FIGS.

  First, FIG. 23 shows a schematic configuration of an electronic apparatus having such a display device.

  23, the electronic device includes a display information output source 1000, a display information processing circuit 1002, a drive circuit 1004, a display panel 1006, a clock generation circuit 1008, and a power supply circuit 1010.

  The display device in each embodiment described above corresponds to the display panel 1006 and the drive circuit 1004 in this embodiment. Therefore, the drive circuit 1004 may be mounted on the TFT array substrate constituting the display panel 1006, and the display information processing circuit 1002 or the like may be further mounted. Alternatively, the driving circuit 1004 may be externally attached to the TFT array substrate on which the display panel 1006 is mounted.

  The display information output source 1000 includes a ROM (Read Only Memory), a RAM (Random Access Memory), a memory such as an optical disk device, a tuning circuit that tunes and outputs a television signal, and the like. Based on this, display information such as an image signal in a predetermined format is output to the display information processing circuit 1002. The display information processing circuit 1002 is configured to include various known processing circuits such as an amplification / polarity inversion circuit, a phase expansion circuit, a rotation circuit, a gamma correction circuit, and a clamp circuit, and a display input based on a clock signal. A digital signal is sequentially generated from the information and output to the drive circuit 1004 together with the clock signal CLK. The drive circuit 1004 drives the display panel 200. The power supply circuit 1010 supplies predetermined power to the above-described circuits.

  Next, FIGS. 24 to 25 show specific examples of the electronic apparatus configured as described above.

  In FIG. 24, a laptop personal computer (PC) 1200 compatible with multimedia, which is another example of an electronic device, includes the above-described display panel 200 in a top cover case 1206, and further includes a CPU, a memory, and a modem. And a main body 1204 in which a keyboard 1202 is incorporated.

  As shown in FIG. 25, in the case of a display panel 1304 that does not include the drive circuit 1004 or the display information processing circuit 1002, an IC 1324 including the drive circuit 1004 or the display information processing circuit 1002 is mounted on a polyimide tape 1322. (Tape Carrier Package) 1320 can be physically and electrically connected to the periphery of the TFT array substrate 1 through an anisotropic conductive film to produce, sell, use, etc. as a display panel Is possible.

In addition to the electronic devices described above with reference to FIGS. 24 to 25, a television, viewfinder type or monitor direct-view type video tape recorder, car navigation device, electronic notebook, calculator, word processor, engineering workstation (EWS) ), A mobile phone, a video phone, a POS terminal, a device equipped with a touch panel, and the like are examples of the electronic device shown in FIG.

  As described above, according to the present embodiment, high-quality image display can be performed for a long time without adversely affecting the display due to deterioration over time in current-driven light-emitting elements such as organic EL elements and drive elements such as current TFTs. Various electronic devices that can be used over a wide range can be realized.

  The display device according to the present invention can be used as a display device including various current-driven light-emitting elements such as organic EL elements, inorganic EL elements, light-emitting polymers, and LEDs, and drive elements such as TFTs that drive the light-emitting elements. Furthermore, the pixel circuit according to the present invention can be used for various active matrix drive display devices. The electronic apparatus according to the present invention is configured using such a pixel circuit and a display device, and can be used as an electronic apparatus that can perform high-quality image display over a long period of time.

It is a block diagram which shows the fundamental whole structure of the display apparatus common to each Example of this invention. It is a top view in one pixel of the display apparatus of FIG. It is a block diagram of the display apparatus of Example 1 of this invention. FIG. 6 is a characteristic diagram illustrating a relationship between a gradation level (D) of an image signal, a data signal voltage (Vsig), and a drive current (Id) and a method for correcting deterioration with time in Example 1. 6 is a block diagram of a modified example of Embodiment 1. FIG. It is a block diagram of the other modification of Example 1. FIG. FIG. 7 is a characteristic diagram illustrating a relationship between a data signal (V sig) and a drive current (Id) and a method for correcting deterioration with time in the modification of FIG. 6. It is a block diagram of the display apparatus of Example 2 of this invention. It is a block diagram of the display apparatus of Example 3 of this invention. It is a block diagram of the display apparatus of Example 4 of this invention. It is the equivalent circuit schematic in one pixel of the display apparatus of Example 5 of this invention. It is the equivalent circuit schematic in one pixel of the display apparatus of Example 6 of this invention. It is the equivalent circuit schematic in one pixel of the display apparatus of Example 7 of this invention. It is an equivalent circuit schematic in one pixel of the display apparatus of Example 8 of this invention. It is the equivalent circuit schematic in one pixel of the display apparatus of Example 9 of this invention. It is an equivalent circuit schematic in one pixel of the display apparatus of Example 10 of this invention. It is a block diagram which shows the whole structure of the display apparatus of Example 11 of this invention including the circuit diagram of one pixel. FIG. 50 is a circuit diagram of a common line driving circuit included in the display device of Example 11. It is a block diagram which shows the whole structure of the display apparatus of Example 12 of this invention including the circuit diagram of 1 pixel. It is sectional drawing of the TFT-OELD part with which the display apparatus of Example 12 is provided. FIG. 34 is a characteristic diagram illustrating a method for correcting deterioration with time in the display device according to the twelfth embodiment. It is a characteristic view which shows the correction method of deterioration with time in the display apparatus of Example 13 of the present invention. It is a block diagram which shows schematic structure of embodiment of the electronic device by this invention. It is a front view which shows the personal computer as an example of an electronic device. It is a perspective view which shows the liquid crystal device using TCP as another example of an electronic device.

Explanation of symbols

213 first power supply line, 215 second power supply line, 221 second thin film transistor,
222 holding capacitor, 223 first thin film transistor, 224 light emitting element,
231 to 234 Thin film diode for correction

Claims (14)

Provided in each of a plurality of matrix-like pixels constituting a display region of a display device provided with at least a signal wiring to which a data signal is supplied and a first and a second power supply line to which power for supplying a driving current is supplied. A pixel circuit,
A current-driven light emitting device connected between the first and second feeder lines;
The drive current flowing through the light emitting element via a source and a drain connected in series with the light emitting element between the first and second feeder lines is controlled according to the voltage of the data signal supplied to the gate. A first thin film transistor element;
Depending on the relationship between the voltage across the light emitting element and the current amount of the drive current, the current amount of the drive current is adjusted by adjusting a resistance between the first power supply line and the second power supply line. A drive current compensation element that increases the drive current according to a decrease in
A pixel circuit comprising: The potential of the first power supply line is set to a higher potential than the second power supply line,
The drive current compensating element has a gate connected to the electrode on the first feeder line side of the light emitting element, and a source and a drain connected in series with the light emitting element between the light emitting element and the second feeder line. The pixel circuit according to claim 1, further comprising an n-channel first correction thin film transistor. The potential of the first power supply line is set to a lower potential than the second power supply line,
The drive current compensating element has a gate connected to the electrode on the first feeder line side of the light emitting element, and a source and a drain connected in series with the light emitting element between the light emitting element and the second feeder line. 2. The pixel circuit according to claim 1, further comprising a first p-channel type correction thin film transistor. The potential of the first power supply line is set to a higher potential than the second power supply line,
The drive current compensation element has a gate connected to the electrode on the second feeder line side of the light emitting element, and a source and a drain connected in series with the light emitting element between the light emitting element and the first feeder line. The pixel circuit according to claim 1, further comprising a p-channel second correction thin film transistor. The potential of the first power supply line is set to a lower potential than the second power supply line,
The drive current compensation element has a gate connected to the electrode on the second feeder line side of the light emitting element, and a source and a drain connected in series with the light emitting element between the light emitting element and the first feeder line. The pixel circuit according to claim 1, further comprising an n-channel second correction thin film transistor. Provided in each of a plurality of matrix-like pixels constituting a display region of a display device provided with at least a signal wiring to which a data signal is supplied and a first and a second power supply line to which power for supplying a driving current is supplied. A pixel circuit,
A current-driven light emitting device connected between the first and second feeder lines;
The drive current flowing through the light emitting element via a source and a drain connected in series with the light emitting element between the first and second feeder lines is controlled according to the voltage of the data signal supplied to the gate. A first thin film transistor element;
A storage capacitor connected to a gate of the first thin film transistor and holding a gate voltage of the first thin film transistor;
Depending on the relationship between the voltage across the light emitting element and the amount of the drive current, the drive current is adjusted by adjusting a resistance between one of the first and second feeder lines and the storage capacitor. A drive current compensation element that increases the drive current according to a decrease in the amount of current;
A pixel circuit comprising: The potential of the first power supply line is set to a higher potential than the second power supply line,
The drive current compensation element includes a first thin film transistor in which a gate is connected to an electrode on the first feeder line side of the light emitting element, and a source and a drain are connected between the storage capacitor and the first feeder line. 7. The pixel circuit according to claim 6, further comprising a third correction thin film transistor of the same n-channel or p-channel type. The potential of the first power supply line is set to a lower potential than the second power supply line,
The drive current compensation element includes a first thin film transistor in which a gate is connected to an electrode on the first feeder line side of the light emitting element, and a source and a drain are connected between the storage capacitor and the first feeder line. 7. The pixel circuit according to claim 6, further comprising a third correction thin film transistor of the same n-channel or p-channel type. The potential of the first power supply line is set to a higher potential than the second power supply line,
The drive current compensation element includes a first thin film transistor in which a gate is connected to an electrode on the first feeder line side of the light emitting element, and a source and a drain are connected between the storage capacitor and the second feeder line. The pixel circuit according to claim 6, further comprising an n-channel or p-channel fourth correction thin film transistor opposite to the above. The potential of the first power supply line is set to a lower potential than the second power supply line,
The drive current compensation element includes a first thin film transistor in which a gate is connected to an electrode on the first feeder line side of the light emitting element, and a source and a drain are connected between the storage capacitor and the second feeder line. The pixel circuit according to claim 6, further comprising an n-channel or p-channel fourth correction thin film transistor opposite to the above.   The pixel circuit according to claim 1, wherein the driving current compensation element is formed by the same manufacturing process as the first thin film transistor. The signal wiring includes a signal line to which the data signal is supplied and a scanning line to which a scanning signal is supplied,
2. The apparatus of claim 1, further comprising a second thin film transistor connected to the scan signal to be supplied to a gate and to supply the data signal to a gate of the first thin film transistor through a source and a drain. The pixel circuit according to any one of 11 to 11.   13. A display device comprising the pixel circuit according to claim 1 for each pixel.   An electronic apparatus comprising the display device according to claim 13.

Images