JP2004038209A - Display device and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the degradation in luminance caused by the deterioration of a light emitting element etc. <P>SOLUTION: A current capacity measurement section for measuring the current capacity of the driving current flowing in a light emitting element is provided and the current capacity of the driving current of the light emitting element is regulated in accordance with the result obtained in the current capacity measurement section. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a pixel circuit including a light emitting element and a driving element such as a thin film transistor for driving the light emitting element, a display device including such a pixel circuit in each pixel, and an electronic apparatus including the same. In particular, the present invention relates to a driving circuit and a display device capable of correcting the influence of aging degradation of a light emitting element and a driving element, and an electronic apparatus including the same.

As this type of display device, a display device of a type in which a thin film transistor (hereinafter referred to as a TFT) is used as a driving element to drive 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 to the signal line and the scanning line in the display area from the scanning line driving circuit and the signal line driving circuit, 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, according to the voltage of the data signal supplied from the signal line, the current driving type light emitting device disposed between the pixel electrode and the counter electrode. It is configured to control a current flowing through the element.
More specifically, for example, each pixel is provided with a switching TFT, and when a scanning signal is supplied to the gate from a scanning line, a data signal from the signal line is supplied to the driving TFT via the source and the drain. Supply to the gate. The conductance between the source and the drain of the driving TFT is controlled (changed) according to the voltage of the data signal supplied to the gate (that is, the gate voltage). At this time, the gate voltage is held by the storage capacitor connected to the gate for a period longer than the period when the data signal is supplied. By supplying a drive current to the organic EL element and the like via the source and the drain whose conductance is controlled as described above, the organic EL element and the like are driven according to the drive current.

In particular, such an organic EL element having a driving TFT is a current-controlled light-emitting element (hereinafter, referred to as TFT-OELD) for realizing a display panel having a large size, high definition, a 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, the light-emitting element is slightly deteriorated with time. For example, in the case of an organic EL device, it is reported that remarkable deterioration with time is present (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. In addition, these aging degradations vary with the organic EL elements. Further, in a TFT-OEL, a current flowing through the TFT as a driving element may cause deterioration of the TFT over time.

た め Therefore, in a display device using a TFT-OEL, when such an organic EL element or a driving TFT deteriorates with time, image quality deteriorates. That is, deterioration in which the amount of current decreases and deterioration in which the amount of light emission decreases leads to a decrease in screen luminance, and variations in the decrease in current amount and the decrease in the amount of light emission cause screen unevenness. In particular, these deteriorations depend on the emission characteristics of the organic EL element during manufacture, the variations in the voltage-current characteristics and threshold characteristics of the driving TFTs, the history of the display patterns, and the like, leading to the deterioration of the image quality of the entire display device. At the same time, it causes screen unevenness.

Here, for example, Patent Document 1 discloses that an EL element is used as a back light source (backlight) of a liquid crystal display panel so that the brightness of the entire liquid crystal display panel illuminated from behind by the EL element does not decrease. There is disclosed a technique of detecting the luminance of an element and correcting deterioration of the entire rear light source. However, this technique relates to a liquid crystal display panel, and an EL element is not provided in each pixel as a display element, but is simply used as a back light source. Are for different technical fields. In a display device 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, it is possible to extend the life of the display device or improve display quality by correcting temporal deterioration of the current-driven light-emitting element or the driving TFT. At present, the technical problem itself is not recognized by those skilled in the art.

JP 05-01234A

Accordingly, the present invention provides a method for correcting the deterioration of the screen brightness by appropriately correcting the deterioration over time when the current amount or the light emission amount of the current-driven light-emitting element deteriorates with time, or when the deterioration with time occurs. It is a technical object to provide a pixel circuit and a display device including a current-driven light-emitting element capable of reducing screen and screen unevenness, and an electronic device including the same.

The display device according to the present invention is a display device including a plurality of pixels each including a light emitting element, including a current amount measuring unit that measures a current amount of a driving current flowing through the light emitting element, The amount of the drive current of the light emitting element is adjusted based on the result obtained by the measurement unit.

In the above display device, the amount of the drive current may be adjusted by adjusting a power supply voltage supplied to the light emitting element.

The above display device further includes a plurality of signal lines, and each of the plurality of pixels converts the drive current flowing through the light emitting element to a data signal supplied through a corresponding signal line of the plurality of signal lines. A drive element that is controlled accordingly may be included, and the amount of the drive current may be adjusted by adjusting the data signal.

In the above display device, it is preferable that the driving element is formed of a transistor whose conductance between a source and a drain is controlled by the data signal.

In the above display device, it is preferable that the adjustment of the current amount of the drive current performed based on the result obtained by the current amount measurement unit is performed in a non-display period prior to a display period.

In the above display device, it is preferable that the adjustment of the power supply voltage performed based on the result obtained by the current amount measurement unit is performed in a non-display period prior to a display period.

In the display device described above, it is preferable that the adjustment of the data signal performed based on the result obtained by the current amount measurement unit is performed in a non-display period prior to a display period.

The display device according to the present invention is a display device including a plurality of pixels each including a light emitting element, and measures a monitor light emitting element and a current amount of a driving current flowing through the monitor light emitting element. And a drive current flowing through the light emitting element is adjusted based on a result obtained by the current amount measurement unit.

The display device according to the present invention is a display device including a plurality of signal lines and a plurality of pixels, each of the plurality of pixels including the light emitting element and a driving current flowing through the light emitting element. A driving element that controls in accordance with a data signal supplied via a corresponding signal line of the plurality of signal lines, and a current amount measuring unit that measures a current amount of a driving current flowing through the light emitting element, The data signal is adjusted based on a result obtained by the current amount measurement unit.

In the above display device, it is preferable that the adjustment of the amount of the drive current performed based on the result obtained by the current amount measurement unit is performed in a non-display period prior to a display period.
In the display device described above, it is preferable that the adjustment of the data signal performed based on a result obtained by the current amount measurement unit is performed in a non-display period prior to a display period.
The above display device is suitable as a display unit of an electronic device.

Further, the present invention has the following features.
(1) A first display device according to the present invention includes a current-driven 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 for controlling, a power supply unit for supplying power for flowing the driving current to the light emitting element via the driving element via a power wiring, and supplying the data signal to the driving element via a signal wiring A signal wiring driving unit, and a current amount of a driving current flowing through the light emitting element when a data signal of a predetermined voltage is supplied to the driving element via the signal wiring, and a light emission amount of light emitted from the light emitting element. A voltage adjustment unit that adjusts the voltage of at least one of a power supply in the power supply unit and a data signal in the signal line driving unit such that at least one of the power supply units approaches a predetermined reference value. That.

According to the first display device, the 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 drive element from the signal wiring drive unit via the signal wiring. Then, the driving element controls the driving current flowing through the light emitting element 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. Here, for example, when a data signal of a predetermined voltage is supplied to the driving element via the signal wiring during the non-display period, the voltage adjusting unit controls the amount of driving current flowing through the light emitting element or the amount of 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 such that the light emission amount approaches a predetermined reference value (that is, the reference current amount or the reference light emission amount).

Therefore, even if the resistance of the light emitting element or the driving element increases due to the deterioration of the light emitting element or the driving element with time, the driving current hardly flows or the light emitting element hardly emits light. The amount or the amount of light emission is substantially constant. That is, a decrease in the amount of drive current or the amount of light emission due to deterioration of the light-emitting element or the drive element over time can be appropriately corrected by voltage adjustment by the voltage adjustment unit.

Furthermore, if the voltage adjustment by the voltage adjustment unit is individually performed for a plurality of pixels, even if the voltage-current characteristics and the current emission characteristics of the light-emitting element and the driving element vary among the plurality of pixels, the plurality of pixels may be varied. The amount of drive current or the amount of light emission in the light emitting element of the pixel can be substantially constant. That is, it is possible to appropriately correct variations in the amount of drive current and light emission due to variations 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 type light-emitting element such as an organic EL element is driven by a driving element such as a thin film transistor, a decrease in screen luminance due to aging of each element or variation in characteristics is caused. 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 through a source and a drain whose conductance is controlled by a gate voltage while the data signal is supplied to a 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 to the light emitting element via between the source and the 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 of 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 driving current is adjusted by the voltage control unit such that the measured current amount approaches the preset reference current amount.

Therefore, even if the resistance of the light emitting element or the driving element increases due to the deterioration of the light emitting element or the driving element with the passage of time, the driving current hardly flows and the driving current amount 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 element 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 the light emission amount when the data signal of the predetermined voltage is supplied to the driving element; A voltage control unit that adjusts the at least one voltage so that the light emission amount approaches a preset reference light emission 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 driving 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 if the light-emitting element and the driving element deteriorate with time and the resistance of the light-emitting element and the driving element increase and the light-emitting element becomes difficult to emit light, the light emission amount of the light-emitting element is substantially constant. Further, even if the voltage-current characteristics and the current emission characteristics of the light-emitting element and the driving element vary among a plurality of pixels, if the voltage adjustment of the data signal is performed individually for each pixel, the plurality of pixels can be adjusted. And the amount of drive current in the light emitting element can be substantially constant.
(5) In another aspect of the first display device, the display device further includes a controller that controls the voltage adjustment unit to adjust the at least one voltage in a non-display period prior to a 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 adjuster in the non-display period prior to the display period.

Therefore, a part of the display period does not need to be occupied for measurement, and the adjustment operation does not adversely affect the image display during the display period while the voltage adjustment unit appropriately adjusts the voltage. Also, in view of the speed of progress of the deterioration over time in the light emitting element and the driving element, it is often sufficient to perform the adjustment by the power adjustment unit every non-display period such as when the power is turned on, for example.
(6) In order to solve the above-mentioned 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 a display area and for each pixel. A drive element for controlling a drive current flowing through the display light emitting element in accordance with a voltage of a data signal; and a power supply for supplying the drive current to the display light emitting element via the drive element via a power supply wiring. A power supply unit, a signal line drive unit that supplies the data signal to the drive element via a signal line, and a current drive type that is provided in a monitor area and is driven in the same manner as the display light emitting element. A light emitting element for monitoring, and a power supply in the power supply section and a data signal in the signal wiring driving section such that at least one of a current amount and a light emitting 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, the drive current flows to the display light emitting element through the drive element by the power supply from the power supply unit. On the other hand, a data signal is supplied to the drive element from the signal wiring drive unit via the signal wiring. Then, the driving element controls the driving current flowing through 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 of a predetermined voltage is supplied to the drive element via the signal wiring in the non-display period, the current adjustment type current monitor is driven by the voltage adjustment unit in the same manner as 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 such 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, the monitor light emitting element provided in the monitor area is driven by current similarly to the display light emitting element provided in the display area. It is considered to have a similar or similar tendency to aging.

Therefore, due to the aging of the display light-emitting element and the driving element, the resistance of the display light-emitting element and the driving element increase and the driving current becomes difficult to flow, or even if the display light-emitting element hardly emits light, The driving current amount or the light emission amount in the display light emitting element is substantially constant. That is, it is possible to appropriately correct a decrease in the driving current amount or the light emission amount due to the deterioration of the display light emitting element or the driving element with the passage of time by adjusting the voltage of the voltage adjusting unit based on the current amount or the light emission amount in the monitor light emitting element.

Furthermore, if the voltage adjustment by the voltage adjustment unit is individually performed for a plurality of pixels, even if the voltage-current characteristics and the current emission characteristics of the light-emitting element and the driving element vary among the plurality of pixels, the plurality of pixels may be varied. The amount of drive current or the amount of light emission in the light emitting element of the pixel can be substantially constant. That is, it is possible to appropriately correct variations in the amount of drive current and light emission due to variations 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 type light-emitting element such as an organic EL element is driven by a driving element such as a thin film transistor, a decrease in screen luminance due to aging of each element or variation in characteristics is caused. 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 data is supplied to a gate and the driving current flows through a source and a drain whose conductance is controlled by a gate voltage. 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 to the display light emitting element through the space between the source and the 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 may include a current amount measurement unit that measures an amount of current in the monitor light-emitting element, and a reference current in which the measured amount of current is set in advance. A voltage controller for adjusting the at least one voltage to approach the amount.

According to this aspect, the amount of current 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 driving current is adjusted by the voltage control unit such that the measured current amount approaches the preset reference current amount.

Therefore, even if the resistance of the light emitting element or the driving element increases due to the deterioration of the light emitting element or the driving element with the passage of time, the driving current hardly flows and the driving current amount 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 a plurality of pixels, if the voltage adjustment is performed individually for each pixel, the driving current amount in the light emitting element of the plurality of pixels can be adjusted. Can be made almost constant.
(9) In another aspect of the second display device, the voltage adjustment unit may include a light emission amount measurement unit that measures a light emission amount of the monitor light emitting element, and a reference light emission in which the measured light emission amount is set in advance. A voltage controller for adjusting the at least one voltage to approach the amount.

According to this aspect, the light emission amount of 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 if the light-emitting element and the driving element deteriorate with time and the resistance of the light-emitting element and the driving element increase and the light-emitting element becomes difficult to emit light, the light emission amount of the light-emitting element is substantially constant. Further, even if the voltage-current characteristics and the current emission characteristics of the light-emitting element and the driving element vary among a plurality of pixels, if the voltage adjustment of the data signal is performed individually for each pixel, the plurality of pixels can be adjusted. And 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 adjustment unit to adjust the at least one voltage in a non-display period prior to a 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 prior to the display period. Therefore, even though the voltage is appropriately adjusted by the voltage adjusting unit, 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, the display light-emitting element and the monitor light-emitting element are operated in similar or similar environments, so that the tendency of deterioration with time in both of them can be made similar or similar. Therefore, it is possible to accurately adjust the voltage of the display light emitting element based on the amount of current and the amount of light emitted from 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, a separate manufacturing process is not required for manufacturing the monitor light emitting element, which is advantageous in manufacturing. In addition, the characteristics of the display light-emitting element and the characteristics of the monitor light-emitting element can be made similar or similar relatively easily. Accordingly, the tendency of the 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 supplying the driving current to both the display light emitting element and the monitor light emitting element during a display period.

According to this aspect, in the display period, since the drive current is supplied to both the display light emitting element and the monitor light emitting element, the tendency of the deterioration over time in both can be made similar or similar.
(14) In order to solve the above-described technical problem, the pixel circuit of the present invention includes 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 drive current is supplied. A pixel circuit provided in each of a plurality of pixels in a matrix forming a display area of the display device, wherein the current driving type light emitting element connected between the first and second power supply lines; A first controlling a 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 power supply lines in accordance with a voltage of the data signal supplied to a gate; A thin film transistor (a thin film transistor for current control), and a drive for increasing the drive current in accordance with at least one of a decrease in the amount of the drive current and a decrease in the amount of light emitted from the light emitting element. A current compensation element.

According to the pixel circuit of the present invention, the driving current flows to the light emitting element through the source and the drain of the first thin film transistor due to the power supply from the first and second power supply lines. On the other hand, a data signal is supplied to a gate of the first thin film transistor via a signal wiring. Then, the conductance between the source and the 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 manner is increased by the drive current compensating element in accordance with a decrease in the amount of the drive current or the amount of light emitted from the light emitting element.

Therefore, even if the driving current becomes difficult to flow due to the deterioration of the light emitting element or the first thin film transistor with the passage of time due to the resistance of the light emitting element or the first thin film transistor or the light emitting element hardly emits light, the light emitting element The amount of drive current or the amount of light emission is substantially constant. That is, it is possible to automatically correct the decrease in the amount of drive current or the amount of light emission due to the deterioration of the light emitting element or the first thin film transistor with the passage of time by the action of the drive current compensator to increase the drive current due to the decrease in resistance or the like.

Further, since such correction is individually performed for a plurality of pixels, even if the voltage-current characteristics and the current emission characteristics of the light emitting element and the first thin film transistor vary among the plurality of pixels, the correction of the plurality of pixels is performed. The driving 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 variations in the amount of drive current and the amount of light emission due to variations 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 in which a current-driven type light-emitting element such as an organic EL element is driven by the first thin film transistor, a decrease in screen luminance or a decrease in screen luminance due to aging of each element or variation in characteristics. Unevenness can be reduced.
(15) In one aspect of the pixel circuit, the signal line includes a signal line to which the data signal is supplied and a scanning line to which a scanning signal is supplied, and the scanning signal is supplied to a gate and a source and a drain are provided. And a second thin film transistor (a thin film transistor for switching) connected so that the data signal is supplied to a gate of the first thin film transistor via the first thin film transistor.

According to this aspect, when the scanning signal is supplied to the gate of the second thin film transistor via 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 the drain of the second thin film transistor via the signal line, the data signal is supplied to the gate of the first thin film transistor via the source and drain of the second thin film transistor. You.
(16) In another aspect of the pixel circuit, the drive current compensating element may be configured such that the first power supply line and the second power supply line depend on a relationship between a voltage across the light emitting element and a current amount of the drive current. Adjust the resistance between the wires.

According to this aspect, the resistance between the first power supply line and the second power supply line is adjusted by the drive current compensation element depending on the relationship between the voltage at both ends of the light emitting element and the amount of drive current. Accordingly, the drive current is increased in accordance with the decrease in the amount of the drive current.
(17) In the aspect in which the adjustment is performed depending on the relationship between the voltage and the current amount, the potential of the first power supply line is set to be higher than that of the second power supply line, and the drive current compensating element is An n-channel type in which a gate is connected to the electrode on the first power supply 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 power supply line. It may be configured to include one correction thin film transistor.

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 the drive current. Can be
(18) Alternatively, in the aspect in which the adjustment is performed depending on the relationship between the voltage and the current amount, the potential of the first power supply line is set to be lower than that of the second power supply line, and the drive current compensation is performed. The element is a p-channel type in which a gate is connected to the electrode on the first power supply 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 power supply line. May be configured to include the first correction thin film transistor.

In this case, the resistance between the first power supply line and the second power supply line is adjusted by the p-channel type first correction thin film transistor, and the drive current increases in accordance with a decrease in the amount of the drive current. Can be
(19) Alternatively, in the aspect in which the adjustment is performed depending on the relationship between the voltage and the current amount, the potential of the first power supply line is set to be higher than the potential of the second power supply line, and the drive current compensation is performed. The element is a p-channel type in which a gate is connected to the electrode on the second power supply 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 power supply line. May be configured to include the second correction thin film transistor.

In this case, the resistance between the first power supply line and the second power supply line is adjusted by the p-channel type second correction thin film transistor, and the drive current increases in accordance with a decrease in the amount of the drive current. Can be
(20) Alternatively, in the aspect in which the adjustment is performed depending on the relationship between the voltage and the current amount, the potential of the first power supply line is set to be lower than the potential of the second power supply line, and the drive current compensation is performed. The element is an n-channel type in which a gate is connected to the electrode on the second power supply 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 power supply line. May be configured to include the second correction thin film transistor.

In this case, the resistance between the first power supply line and the second power supply line is adjusted by the n-channel type second correction thin film transistor, and the drive current increases in accordance with the decrease in the amount of the drive current. Can be
(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 holding 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 allow a drive current to flow through the source and the drain of the first thin film transistor for a period longer than a period for providing a data signal.
(22) In the aspect having the storage capacitor, the drive current compensating element depends on the relationship between the voltage between both ends of the light emitting element and the amount of the drive current. You may comprise so that the resistance between one and the said storage capacitor may be adjusted.

According to this aspect, the resistance between the first or second power supply line and the storage capacitor is adjusted by the drive current compensating 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 according to the decrease in the amount of the drive current.
(23) In the aspect in which the resistance between the power supply line and the storage capacitor is adjusted as described above, the potential of the first power supply line is set to be higher than the potential of the second power supply line, and the drive current compensation is performed. The same n or the same as the first thin film transistor, wherein a gate is connected to the electrode on the first power supply line side of the light emitting element, and a source and a drain are connected between the storage capacitor and the first power supply line. A third correction thin film transistor of a 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 same n- or p-channel third correction thin film transistor as the first thin film transistor, and the second power supply line is connected to the second power supply line. The drive current is increased in accordance with a decrease in the amount of the drive current flowing toward the electric wire.
(24) Alternatively, in such an embodiment in which the resistance between the power supply line and the storage capacitor is adjusted, the potential of the first power supply line is set to a lower potential than the second power supply line, and The current compensation element is the same as the first thin film transistor, wherein a gate is connected to the electrode on the first power supply line side of the light emitting element, and a source and a drain are connected between the storage capacitor and the first power supply line. It may be configured to include an n or p channel type third correction thin film transistor.

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 type third correction thin film transistor as the first thin film transistor, and 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 the drive current flowing toward the electric wire.
(25) Alternatively, in such an embodiment in which the resistance between the power supply line and the storage capacitor is adjusted, the potential of the first power supply line is set to be higher than the potential of the second power supply line, and The current compensating element has a gate connected to the electrode on the first power supply line side of the light emitting element, and a source and a drain opposite to the first thin film transistor connected between the storage capacitor and the second power supply line. May be configured to include the n- or p-channel type fourth correction thin film transistor.

In this case, the resistance between the first or second power supply line and the storage capacitor is adjusted by the n- or p-channel type fourth correction thin film transistor opposite to the first thin film transistor, and the resistance from the first power supply line to the second The drive current is increased in accordance with a decrease in the amount of the drive current flowing toward the power supply line.
(26) Alternatively, in the aspect in which the resistance between the power supply line and the storage capacitor is adjusted as described above, the potential of the first power supply line is set to be lower than the potential of the second power supply line. The current compensating element has a gate connected to the electrode on the first power supply line side of the light emitting element, and a source and a drain opposite to the first thin film transistor connected between the storage capacitor and the second power supply line. May be configured to include the n- or p-channel type fourth correction thin film transistor.

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 type fourth correction thin-film transistor opposite to the first thin-film transistor, and the resistance from the second power supply line to the first is reduced. The drive current is increased in accordance with a decrease in the amount of the drive current flowing toward the power supply line.
(27) In another aspect of the pixel circuit, the drive current compensating element may be connected to the first power supply line and the second power supply line depending on a relationship between a voltage between both ends of the light emitting element and the light emission amount. Adjust the resistance between them.

According to this aspect, the resistance between the first power supply line and the second power supply line is adjusted by the drive current compensating element depending on the relationship between the voltage at both ends of the light emitting element and the light emission amount, so that light emission is achieved. 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 compensating element may be connected to the first and second power supply lines depending on a relationship between a voltage between both ends of the light emitting element and the light emission amount. You may comprise so that the resistance between one and the said storage capacitor may be adjusted.

According to this aspect, the resistance between the first or second power supply line and the storage capacitor is adjusted by the drive current compensating element depending on the relationship between the voltage at both ends of the light emitting element and the light emission amount. The drive current is increased in accordance with the decrease in the light emission amount.
(29) 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 the potential of the second power supply line. The first thin film transistor is set to a potential, 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 power supply line. 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 second power supply line is supplied from the first power supply line to the p-channel first thin film transistor. The drive current flowing toward the electric wire is increased in accordance with the decrease in the light emission amount.
(30) 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 also set to a high potential, the first thin film transistor is a p-channel type, and the drive current compensating element is a fifth transistor having a source and a drain connected between the storage capacitor and the first power supply line. May be included.

In this case, the resistance between the first or second power supply line and the storage capacitor is adjusted by the fifth correction thin film transistor, and the p-channel first thin film transistor is connected from the first power supply line to the second power supply line. The driving current flowing toward the light source is increased in accordance with the decrease in the light emission amount.
(31) 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 also set to a low potential, the first thin film transistor is 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. It may be configured to include a photodiode.

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 line is supplied to the n-channel type first thin film transistor from the second power supply line. The drive current flowing toward the electric wire is increased in accordance with the decrease in the light emission amount.
(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 also set to a low potential, the first thin-film transistor is an n-channel type, and the drive current compensating element is a fifth transistor having a source and a drain connected between the storage capacitor and the first power supply line. May be included.

In this case, the resistance between the first or second power supply line and the storage capacitor is adjusted by the fifth correction thin film transistor, and the n-channel first thin film transistor is connected from the second power supply line to the first power supply line. The driving current flowing toward the light source is increased in accordance with the decrease in the light emission amount.
(33) 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 also set to a high potential, the first thin film transistor is an n-channel type, and the drive current compensation element is a second correction thin film connected between the storage capacitor and the second power supply line. It may be configured to include a photodiode.

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 line is supplied to the n-channel first thin film transistor from the first power supply line. The drive current flowing toward the electric wire is increased in accordance with the decrease in the light emission amount.
(34) 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 also set to a high potential, the first thin film transistor is an n-channel type, and the drive current compensating element is a sixth drive source and drain connected between the storage capacitor and the second power supply line. May be included.

In this case, the resistance between the first or second power supply line and the storage capacitor is adjusted by the sixth correction thin film transistor, and the n-channel first thin film transistor is connected from the first power supply line to the second power supply line. The driving current flowing toward the light source is increased in accordance with the decrease in the light emission amount.
(35) 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 also set to a low potential, the first thin film transistor is a p-channel type, and the drive current compensation element is a second correction thin film connected between the storage capacitor and the second power supply line. It may be configured to include a photodiode.

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 first power supply line is supplied from the second power supply line to the p-channel first thin film transistor. The drive current flowing toward the electric wire is increased in accordance with the decrease in the light emission amount.
(36) 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 also set to a low potential, the first thin film transistor is a p-channel type, and the drive current compensating element is a sixth transistor having a source and a drain connected between the storage capacitor and the second power supply line. May be included.

In this case, the resistance between the first or second power supply line and the storage capacitor is adjusted by the sixth correction thin film transistor, and the p-channel first thin film transistor is connected from the second power supply line to the first power supply line. The driving current flowing toward the light source is increased in accordance with the decrease in the light emission amount.
(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, a separate manufacturing process is not required to manufacture the drive current compensating element, which is advantageous in manufacturing.
(38) In order to solve the above-mentioned technical problem, the third display device of the present invention includes a current-driven light-emitting element provided for each pixel and a current-driven light-emitting element provided for each pixel and flowing to the light-emitting element. A driving element that controls a driving current according to a voltage of a data signal, a power supply unit that supplies a power for flowing the driving current to the light emitting element through the driving element via a power supply wiring, and an image signal source. A signal line drive circuit for supplying a data signal having a voltage corresponding to an input image signal to the drive element via a signal line, and a data signal of a predetermined voltage supplied to the drive element via the signal line A measurement unit that measures at least one of a current amount of a driving current flowing through the light emitting element and a light emission amount of light emitted from the light emitting element, and a measuring unit that is interposed between the image signal source and the signal line driving circuit. 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, the drive current flows through the light emitting element through the drive element by the power supply from the power supply unit. On the other hand, a data signal input from an image signal source and having a voltage corresponding to the image signal is supplied to the drive element from a signal line drive circuit via a signal line. Then, the driving element controls the driving current flowing through the light emitting element 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. Here, for example, when a data signal of a predetermined voltage is supplied to the driving element via the signal line in the non-display period, the measuring unit measures the amount of driving current flowing through the light emitting element or the amount of light emission of the light emitting element. You. 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 driving 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 if the resistance of the light emitting element or the driving element increases due to the deterioration of the light emitting element or the driving element with time, the driving current hardly flows or the light emitting element hardly emits light. The amount or the amount of light emission is substantially constant.

Furthermore, if the correction by the correction circuit is individually performed for a plurality of pixels, even if the voltage-current characteristics and the current emission characteristics of the light-emitting element and the driving element vary among the plurality of pixels, the plurality of pixels The amount of drive current or the amount of light emission in the light emitting element can be made substantially constant.

As a result, according to the third display device, in a display device in which a current-driven type light-emitting element such as an organic EL element is driven by a driving element such as a thin film transistor, a decrease in screen luminance due to deterioration with time or variation in characteristics 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 a 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 to the light emitting element via between the source and the 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 for storing at least one of the measured current amount and the light emission amount, and the correction circuit includes the stored current amount and the light emission amount. 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. Then, the image signal is corrected by the correction circuit based on the stored current amount or light emission amount. Therefore, it is possible to perform correction in the display period by performing measurement in the non-display period that is temporally before and after the display period. Further, 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 line is provided corresponding to a pixel column, and the measuring unit measures the amount of the drive current and displays the power supply line. 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 for sequentially outputting pulses sequentially to each of the power supply lines, and the non-display period. A common line driving circuit including a transmission switch for sequentially controlling conduction between each of the power supply wirings and the measurement unit in accordance with the sequential pulse.

According to this aspect, in the common line driving circuit, during the display period, the power supply wiring is connected to the power supply unit by the changeover switch. Accordingly, the light-emitting element receives light from the power supply unit and emits light to perform 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 the changeover switch. At this time, a pulse is sequentially output from the shift register corresponding to each of the power supply lines, and conduction between each of the power supply lines and the measuring unit is sequentially established by the transmission switch in accordance with the pulse. Then, the measuring unit measures the amount of the driving current. Therefore, by sequentially selecting the power supply wiring provided corresponding to the pixel column as a measurement target, the amount of current can be measured for each pixel column, and further, the light emitting element is driven for each row using a scanning signal. Is adopted, it becomes possible to measure the amount of current for each pixel. As a result, correction can be performed for each pixel column or each pixel.
(42) In another aspect of the third display device, the measuring unit measures the light emission amount and transmits an electric signal indicating the light emission amount, which is provided corresponding to a pixel column, to the measurement unit. An inspection light beam, a shift register for sequentially outputting a sequential pulse in response to each of the inspection light beams, and sequentially controlling conduction between each of the inspection light beams and the measurement unit according to the sequential pulses in a non-display period. And a light detection drive circuit including a transmission switch.

According to this aspect, in the non-display period, the shift register sequentially outputs pulses sequentially corresponding to each of the inspection light beams, and the transmission switch sequentially switches between each of the inspection light beams and the measurement unit according to the pulse. Are sequentially conducted. Then, the light emission amount is measured by the measurement unit. Therefore, by sequentially selecting the inspection light beam provided corresponding to the pixel column as a measurement object, it becomes possible to measure the light emission amount for each pixel column, and further, to drive the light emitting elements for each row using a scanning signal. Is adopted, it becomes possible to measure the light emission amount for each pixel. As a result, correction can be performed for each pixel column or 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, highly accurate measurement can be performed using a relatively simple element.
(44) In the aspect in which the measurement is performed using the photoexcitation current of the semiconductor element, 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 in which the measurement is performed by the photoexcitation current of the semiconductor element, 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 in which measurement is performed using the photoexcitation current of the semiconductor element, 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 step, which is advantageous in manufacturing.
(47) In another aspect of the third display device, the driving element is formed of a polycrystalline silicon thin film transistor formed by a low-temperature process at 600 ° C. or lower.

According to this aspect, it is possible to produce a driving element having high driving capability on a relatively low-cost large-sized glass substrate or the like at low cost.
(48) In another aspect of the third display device, the light emitting element is an organic electroluminescence element formed by an inkjet process.

According to this aspect, a light-emitting element having high luminous efficiency and long life can be manufactured, and patterning on a substrate can be easily performed. Further, since the amount of waste material during the process is small and the cost of the process equipment is relatively low, the cost of the display device can be reduced.
(49) 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 pixel, and the correction circuit converts 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 are variations in the voltage-current characteristics and the current emission characteristics of the light-emitting element and the drive element among the plurality of pixels due to differences in the degree of deterioration due to manufacturing variations and display histories, the plurality of pixels have variations. The amount of drive current or the amount of light emission in the light emitting element of the pixel can be made substantially constant. As a result, the screen unevenness due to the characteristic variation 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 performs the measurement on the predetermined unit. 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 measuring unit for each predetermined unit including a plurality of pixels, and the image signal is corrected by the correction circuit for each predetermined unit. The predetermined unit is composed of, for example, n (n = 2, 4, 8, 16, 32, 64,...) Pixels adjacent to each other. What is necessary is just to determine according to the processing capacity of a correction circuit. Therefore, even if there are variations in the voltage-current characteristics and current emission characteristics of the light-emitting element and the drive element among a plurality of predetermined units due to differences in the degree of deterioration due to manufacturing variation or display history, the variation is not considered. The amount of drive current or the amount of light emission in the predetermined unit of light emitting elements can be made substantially constant. As a result, it is possible to efficiently reduce the screen unevenness due to the characteristic variation of each element. Such measurement and correction can be performed in a relatively short time and easily as compared with the case where measurement and correction are performed for each pixel.
(51) In another aspect of the third display device, the correction circuit corrects the image signal by converting a signal level of the image signal from a predetermined signal level to another predetermined signal level.

According to this aspect, at the time of correction by the correction circuit, the signal level of the image signal is converted from a predetermined signal level to another predetermined signal level, so that a signal level different from the specified signal level is provided. There is no need to keep it. Accordingly, for example, the configuration of the signal line driver circuit can be simplified, and the types of power supplies required in the signal line driver circuit can be reduced. As a result, as a display device, simplification of a circuit, high-speed operation, and reduction in current consumption can be realized.
(52) A fourth display device according to the present invention is characterized in that the pixel circuits according to the various aspects of the present invention described above are provided for each pixel in order to solve the above technical problem.

According to the fourth display device, since the pixel circuit of the present invention is provided for each pixel, a high-quality image with reduced screen luminance and screen unevenness due to aging deterioration and characteristic variation in light emitting elements and driving elements is reduced. Display becomes possible.
(53) In order to solve the above technical problems, an electronic apparatus according to the present invention includes any one of the first, second, and third display devices according to the various aspects of the present invention. I do.

According to the electronic device of the present invention, since the display device of the present invention is provided, high-quality image display with reduced screen luminance and reduced screen unevenness due to aging deterioration and characteristic variation in light emitting elements and driving elements can be performed. Various electronic devices can be realized.

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

First, FIGS. 1 and 2 show a basic configuration common to a display device including a TFT-OELD (that is, a driving thin film transistor and an organic EL element driven by the thin film transistor) of each embodiment described below. It will be described with reference to FIG. FIG. 1 is a block diagram showing a basic overall configuration of the display device, and particularly includes a circuit diagram showing 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 a plurality of scanning lines 131 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 for supplying a scanning signal to the scanning line 131, and the signal line driving circuit 12 for supplying a data signal to the signal line 132 And a common line driving circuit 13 that supplies a positive power supply (or a negative power supply) of a predetermined potential to the common line 133. A display area 15 is provided at 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 (hereinafter, referred to as an example) of a first thin film transistor controlled by the switching TFT 221 to control current to each pixel. 223, a pixel circuit including an organic EL element 224 and a storage capacitor 222. 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. And the like are disposed facing each other. The counter electrode is, for example, grounded or connected to a negative power supply (or positive power supply) having a predetermined potential.

た め With the above configuration, 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 to the signal line 132 from the signal line driving circuit 12, the scanning line driving circuit 11 corresponds to the scanning line 131 and the signal line 132. The switching TFT 221 in the corresponding pixel 10 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 from the common line drive circuit 13 to the drain and source of the current TFT 223 via the common line 133, and further to the organic EL via the pixel electrode 141 (see FIG. 2). The organic EL element 224 emits light by flowing from the element 224 to the counter electrode. Then, 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 remains at a predetermined level even after the switching TFT 221 is turned off. Continue to flow over the period.

In each of the embodiments described below, the current-driven light-emitting element that is current-driven in each pixel of the display device is an organic EL element. However, in place of this organic EL element, other elements such as inorganic electroluminescent elements are used. The display device is configured using known current-driven light-emitting elements such as an inorganic EL element (hereinafter, referred to as an inorganic EL element), an LED (light-emitting diode = light-emitting diode), and an LEP (light-emitting polymer). May be. The drive element for controlling the drive current of each current drive type light emitting element is a current TFT. Instead of this current TFT, another drive element such as an FET (field effect transistor) or a bipolar transistor is used. May constitute the display device. In the case of a current-driven type light-emitting element or a current-driven drive element, the effect of each of the embodiments described below is exerted because deterioration with the passage of time occurs as the drive current flows. However, when a display device is configured using the organic EL element 224 and the current TFT 223 whose deterioration with time is particularly remarkable, the effects of the respective embodiments described below are effectively exhibited.

In the basic configuration described above, a circuit or an element for appropriately correcting the deterioration over time or variation in characteristics of the organic EL element 224 and the current TFT 223 shown in the following Examples 1 to 13 is added, so that the display area 15 can be obtained. It is possible to prevent a decrease in screen luminance and the occurrence of screen unevenness between the plurality of pixels 10. Hereinafter, each embodiment will be described.

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 driving 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 signal of a predetermined potential (for example, a ground potential) to a counter electrode that is disposed to face the pixel electrode 141 (see FIG. 2) with the organic EL element 224 interposed therebetween.

In this embodiment, in particular, in order to correct a decrease in drive current due to the aging of the organic EL element 224 and the current TFT 223 (accordingly, a decrease in the amount of light emitted from 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 driving circuit 13, the counter electrode driving circuit 14, the current measuring device 16, the comparison circuit 21a, the voltage control circuit 22a and the controller 23 is provided on the TFT array substrate 1 shown in FIG. Or may be configured as an external IC and externally attached to the TFT array substrate 1.

The current amount measuring device 16 measures a driving current flowing from the common electrode driving circuit 13 to the display organic EL element 224 (see FIG. 1) in the display area 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 I ref, and the voltage control circuit 22a determines a 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 as to reduce. That is, feedback is applied to the output voltage (V com) from the common electrode drive 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 the deterioration with time of the organic EL element 224 and the current TFT 223 is the output voltage (V com) of the common electrode drive circuit 13. Is corrected by the increase in the drive current due to the increase in the drive current.

補正 The correction operation according to the present embodiment will be described with reference to FIG.

First, the case where the correction is not performed as in the present embodiment will be described with reference to the upper part of FIG. In this case, when a data signal of the voltage V1 is supplied to the signal line when displaying a pixel corresponding to the gradation level D1 of the image signal, the common electrode potential, the counter electrode potential, and the data in the display device are set so that the drive current Id1 flows. It is assumed that the power supply potential and the like of the signal have been initialized. Thereafter, when the organic EL element or the current TFT deteriorates with time, the driving current Id flowing through the organic EL element decreases even if a data signal of the same voltage V1 is supplied (here, the current after the decrease is represented by Id1). '). Therefore, when an image is displayed with the various voltages set as they are, the brightness (luminance) of the organic EL element that emits light in accordance with the drive current Id is reduced.

Next, the case of performing the correction as in the present embodiment will be described with reference to the lower part of FIG. In this case, even if the organic EL element 224 or the current TFT 223 deteriorates with time, the output from the common electrode driving circuit 13 is obtained so that the same driving current I d1 as in the initial state is 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 drive circuit 13, a data signal having a voltage V1 ′ higher than the voltage V1 by ΔV1 is supplied to the image signal of the gradation level D1. A drive current Id1 similar to that at the time flows.

As described above, the drive current Id flowing through the organic EL element 224 is corrected by increasing the output voltage (V com) of the common electrode drive circuit 13 so that the current characteristic with respect to the image signal becomes the same as the initial state. is there. Therefore, when an image is displayed after the correction processing for such aging degradation (that is, the adjustment processing of the output voltage (Vcom) of the common electrode driving circuit 13), remarkable aging degradation occurs in the organic EL element 224 and the current TFT 223. Also in this case, it is possible to reduce a decrease in brightness (luminance) of the organic EL element 224.

補正 The above-described correction processing can be performed in real time in parallel with the display operation. However, in view of the progression speed of the deterioration with time, it is not necessary to perform the operation all the time during the display operation of the display device 100, and it is sufficient to perform the operation after an appropriate period. Therefore, in the present embodiment, the controller 23 performs a correction process for such a deterioration with time, for example, when the main power supply of the display device 100 is turned on or before a display period and independently of a normal display operation. During 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 last corrected (adjusted) value. According to this configuration, there is obtained 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 of the display device 100 are not reduced.

Further, in the present embodiment, the controller 23 performs such a voltage control circuit while displaying an image of a predetermined pattern in the display area 15 such as supplying a data signal for causing all the organic EL elements 224 to emit light to the maximum. It is configured to perform a correction process by the reference numeral 22a or the like. With this configuration, the amount of current can be measured with high accuracy, and the effect of the deterioration with time can be accurately corrected.

As a result, according to the present embodiment, when time-dependent deterioration occurs in which the amount of the drive current Id flowing through the organic EL element 224 decreases, the amount of current decrease due to the time-dependent deterioration is accurately corrected, and the screen brightness is reduced. It is possible to prevent the reduction from occurring.

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 organic EL element 224. I have. However, as a modified example 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 measured in this manner. ) Or 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 I ref compared in the comparison circuit 21a match. Even when 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 drive circuit may be such that the measured current amount ID compared with the comparison circuit 21a and the reference current amount I ref match. Even when the voltage control circuit 22c for adjusting the voltage of the twelfth is provided, the same effect as in the first embodiment can be obtained.

Further, in the above-described first embodiment and its modifications, the predetermined pattern displayed on the display area 15 when performing the correction processing (the voltage adjustment processing by the voltage control circuit 22a or the like) may be, for example, all the organic One type of pattern that supplies a data signal that causes the EL element 224 to emit light to the maximum may be used, or the measured 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 may be adjusted by the voltage control circuit 22a or the like such that the sum of the differences between the plurality of patterns becomes the smallest as compared with the reference current amount I ref thus obtained.

In particular, in the case of the modification example in which the output voltage of the signal line driving circuit 12 (that is, the voltage V sig of the data signal) shown in FIG. 6 is adjusted, the measurement is performed for a plurality of patterns 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 adjusted as shown in FIG. Each of the values I d1, I d2,..., I dn,... Can be individually increased to each voltage (Vn ′). 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 aging as shown by C1 to C2 (for example, when the change due to aging is more intense on the low current side than on the high current side, or If the correction amount is determined in accordance with the value of each drive current Id in this way, the drive current Id and the light emission amount of the organic EL element 224 are determined for each gradation level of the input image signal. It is possible to maintain with high accuracy.

As described in detail above, according to the present embodiment and its modification, the drive current (measured current amount ID) actually flowing through the organic EL element 224 and the preset reference current (reference current amount I ref) are used. Since the voltage applied to the bus wiring or the electrode is adjusted in accordance with the difference, 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 the TFT-OELD according to the second embodiment of the present invention. 8, the same components as those of the first embodiment shown in FIG. 3 are denoted by the same reference numerals, and the description thereof will be omitted. In the present embodiment, the voltage between the common electrode and the counter electrode is applied to the monitoring organic EL element 17a in the current monitoring area 17 provided adjacent to the display area 15, and during the display period, Under substantially the same conditions as the organic EL element 224 (see FIG. 1), the monitor organic EL element 17a is driven by current. Then, when performing the correction process for the deterioration over time, 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 control the common electrode drive circuit 13 so that the measured current amount ID, which is a measured value of the current I dm by the current amount measuring device 16, matches the reference current amount I ref. It is configured to adjust the output voltage (V com). Other configurations are the same as those in the first embodiment.

With the above-described configuration, according to the second embodiment, when the current amount of the organic EL element 224 and the current TFT 223 (see FIGS. 1 and 2) deteriorates with time, the current due to the time-dependent deterioration occurs. By compensating the decrease, it is possible to reduce the decrease in the screen brightness in the display area 15.

In the present embodiment, particularly, 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. Therefore, it is not necessary to separately provide a step for forming the monitor organic EL element 17a. In addition, it is possible to make the current-driven display organic EL element 224 and the monitor organic EL element 17a similar in terms of aging over time, and the display organic EL element 224 is based on the current I dm flowing through the monitor organic EL element 17a. It is possible to fairly appropriately correct the deterioration over time in the organic EL element 224.

Also, in the second embodiment, similarly to the first embodiment, the correction processing for the aging deterioration may be performed, for example, at the time of turning on the main power supply of the display device 100 or at regular intervals before the display period. May be performed. Further, as a modification, the output voltage of 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 measured in this manner. Good. In particular, in the case of a modification in which the output voltage of the signal line drive circuit 12 is adjusted, the monitor organic EL element 17a is controlled by the controller 23 so that a plurality of displays having different brightnesses are performed in the current monitor area 17. Is driven, the voltage V sig of the data signal is adjusted so that the measured current amount ID obtained for each brightness coincides with the corresponding reference current amount I ref. It is possible to cope with a case where a complicated change occurs.

FIG. 9 is a block diagram of a display device including the TFT-OELD according to the third embodiment 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 description thereof will be omitted.

In the present embodiment, instead of the current amount measuring device 16 in the first embodiment, a light emitting amount measuring device 18 for measuring the light emitting amount of the display organic EL element 224 (see FIG. 1) in the display area 15 is provided. I have. When correcting for the deterioration over 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 a signal from the common electrode driving circuit 13 and the counter electrode driving circuit 14 are output. A power signal of a predetermined voltage is applied. The light emission amount measuring device 18 detects 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 L ref. 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 made to match. ing. Other configurations are the same as those in the first embodiment.

According to the third embodiment configured as described above, the deterioration with time in which the amount of drain current (drive current) with respect to the gate voltage in the current TFT 223 (see FIGS. 1 and 2) decreases, and the amount of current with respect to the voltage in the organic EL element 224 When the light emission amount of the organic EL element 224 finally decreases, the light emission amount decreases due to the deterioration with time. Is corrected by increasing the voltage applied to the organic EL element 224, and it is possible to prevent a decrease in screen luminance in the display area 15.

Also in the third embodiment, similarly to the first embodiment, the correction for the aging deterioration may be performed, for example, at the time of turning on the main power supply of the display device 100 before the display period, at regular intervals, or in real time. May go. Further, as a modification, the output voltage of the scanning line drive circuit 11, the signal line drive circuit 12, or the counter electrode drive circuit 14 may be adjusted in accordance with the measured light emission amount LD measured in this manner. Alternatively, one or a plurality of predetermined patterns may be used when correcting for the deterioration over time. In particular, in the case of a modified example 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 match the corresponding reference light emission amount L ref for a plurality of predetermined patterns. By adjusting the voltage V sig of the data signal, it is possible to cope with a complicated change in the current-voltage characteristic due to aging.

FIG. 10 is a block diagram of a display device including the TFT-OELD according to the fourth embodiment of the present invention. 10, the same components as those in the first and third embodiments shown in FIGS. 3 and 9, respectively, are denoted by the same reference numerals, and the description thereof will be omitted.

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

According to the fourth embodiment configured as described above, similarly to the third embodiment, the deterioration with time, in which the amount of current with respect to the voltage in the current TFT 223 (see FIGS. 1 and 2) and the organic EL element 224 is reduced. When the light emission amount with respect to the drive current in the EL element 224 decreases with time, and the light emission amount in the organic EL element 224 finally decreases, the decrease in the light emission amount is corrected, and the screen brightness in the display area 15 is corrected. Can be prevented from decreasing.

Also in the fourth embodiment, similarly to the first embodiment, the correction for the deterioration over time may be performed, for example, when the main power of the display device 100 is turned on before the display period, at regular intervals, or in real time. May go. Further, as a modification, the output voltage of the scanning line drive circuit 11, the signal line drive circuit 12, or the counter electrode drive circuit 14 may be adjusted in accordance with the measured light emission amount LD measured in this manner. Alternatively, one or a plurality of predetermined patterns may be used when correcting for the deterioration over time. In particular, in the case of a modified example 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 match the corresponding reference light emission amount L ref for a plurality of predetermined patterns. By adjusting the voltage V sig of the data signal, it is possible to cope with a complicated change in the current-voltage characteristic due to aging. In this 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. Therefore, it is not necessary to separately provide a step for forming the monitor EL element 19a. In addition, the current-driven display organic EL element 224 and the monitor organic EL element 19a can have similar aging characteristics, and the display organic EL element 224 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.

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

In Embodiments 5 to 10 below, the configuration of a display device including a plurality of pixel circuits for each pixel is the same as that shown in FIG. 1, and a description thereof will be omitted.
FIG. 11 is an equivalent circuit diagram of a pixel circuit including a TFT-OELD according to the fifth embodiment of the present invention. In FIG. 11, the same components as those shown in the circuit diagram in each pixel 10 in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 11, in the pixel circuit according to the present embodiment, the voltage between the first power supply line 213 and the second power supply line depends on the relationship between the voltage across the organic EL element 224 and the amount of the drive current Id flowing therethrough. 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 supply signal of a predetermined potential is supplied from the common line driving circuit. On the other hand, the portion between the second power supply lines 215 is a power supply line portion in each pixel connected to the counter electrode to which a power signal of 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, a positive power is supplied to the common electrode and a negative voltage is applied to the counter electrode). When 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 power supply line side of the organic EL element 224, A source electrode and a drain electrode are added between the organic EL element 224 and the second power supply line 215 so as to be connected in series with the organic EL element 224. 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 the deterioration over time, the drive current due to the increase in the resistance of the organic EL element 224 due to the decrease in the resistance between the source and the 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. Further, since such correction is performed on a pixel-by-pixel basis, when time-dependent deterioration occurs among a plurality of pixels or when current-voltage characteristics vary among a plurality of pixels in an initial state, the screen is not displayed. Non-uniformity can be prevented.

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, the negative power is supplied to the common electrode and the positive power is supplied to the counter electrode). In this case, the first correction TFT 231 is of a p-channel type, its gate electrode is connected to the electrode on the first power supply line side of the organic EL element 224, and its source and drain electrodes are connected to the organic EL element 224. What is necessary is just to comprise so that it may be connected in series with the organic EL element 224 between 2 feeder 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 the correction is automatically performed. In this embodiment, preferably, the switching TFT 221, the current TFT 223, and the first correction TFT 231 are formed on the same TFT array substrate by the same manufacturing process. According to this configuration, it is possible to correct a 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 Embodiment 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 description thereof will be omitted.

In FIG. 12, in the pixel circuit of the present embodiment, the voltage between the first power supply line 213 and the second power supply line depends on the relationship between the voltage across the organic EL element 224 and the amount of the drive current Id flowing therethrough. 215 is changed.

More specifically, when the potential of the first power supply line 213 is higher than the potential of the second power supply line 215, as shown in FIG. The gate electrode is connected to the electrode on the second power supply line side of the organic EL element 221, and the source electrode and the drain electrode are added between the organic EL element 224 and the first power supply line so as to be connected in series with the organic EL element 224. You. 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 drive current due to the increase in the resistance of the organic EL element 224 due to the decrease in the resistance between the source and the 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. Further, since such correction is performed on a pixel-by-pixel basis, when time-dependent deterioration occurs among a plurality of pixels or when current-voltage characteristics vary among a plurality of pixels in an initial state, the screen is not displayed. Non-uniformity can be prevented.

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 its gate electrode is The organic EL element 224 may be connected to the electrode on the second power supply 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 power supply 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 the correction is automatically performed.

In the present embodiment, preferably, the switching TFT 221, the current TFT 223, and the second correction TFT 232 are formed on the same TFT array substrate by the same manufacturing process. According to this configuration, it is possible to correct a 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 Embodiment 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 description thereof will be omitted.

13, in the pixel circuit according to the present embodiment, the voltage between the storage capacitor 222 and the first power supply line 213 depends on the relationship between the voltage between both ends of the organic EL element 224 and the amount of the drive current Id flowing therethrough. Change the resistance.
More specifically, when the potential of the first power supply line 213 is higher than the potential of the second power supply line 215, as shown in FIG. The TFT 233 is added such that its gate electrode is connected to the electrode on the first power supply line side of the organic EL element 224, and its source electrode and 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 the seventh embodiment, even if the resistance of the organic EL element 224 increases due to the deterioration with time, the driving current due to the increase in the resistance of the organic EL element 224 due to the decrease in the resistance between the source and the 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. Further, since such correction is performed on a pixel-by-pixel basis, when time-dependent deterioration occurs among a plurality of pixels or when current-voltage characteristics vary among a plurality of pixels in an initial state, the screen is not displayed. Non-uniformity can be prevented.

As a modification of the seventh embodiment, when the potential of the first power supply line 213 is higher than that of the second power supply line, the current TFT 223 is set to a p-channel type, and the third correction TFT 233 is set to a p-channel type. Alternatively, 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 the correction is automatically performed.

Further, as another modified example of the seventh embodiment, when the potential of the first power supply line 213 is lower than the potential of the second power supply line 215, the current TFT 223 is an n-channel type, and the third correction TFT 233 is It is configured to be an n-channel type, with its gate electrode connected to the electrode on the first power supply line side of the organic EL element 224, and its source and drain electrodes connected between the storage capacitor 222 and the first power supply line 213. Is 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 the correction is automatically performed.

Further, as another modified example 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 set to the p-channel type, and the third correction TFT 233 is set to p-type. It may be configured to be a channel type, connect the gate electrode to the electrode on the first power supply line side of the organic EL element 224, and connect the source electrode and the drain electrode 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. Therefore, the gate voltage of the current TFT 223 decreases, the resistance between the source electrode and the drain electrode decreases, and the correction is automatically performed.

In the present embodiment, preferably, the switching TFT 221, the current TFT 223, and the third correction TFT 233 are formed on the same TFT array substrate by the same manufacturing process. According to this configuration, it is possible to correct a 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 the 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 description thereof will be omitted.

14, in the pixel circuit of this embodiment, the voltage between the storage capacitor 222 and the second power supply line 215 depends on the relationship between the voltage between both ends of the organic EL element 224 and the amount of the driving current Id flowing therethrough. 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. 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 when the resistance of the organic EL element 224 increases due to the deterioration with time, the drive current due to the increase in the resistance of the organic EL element 224 due to the increase in the resistance between the source and the 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. Further, since such correction is performed on a pixel-by-pixel basis, when time-dependent deterioration occurs among a plurality of pixels or when current-voltage characteristics vary among a plurality of pixels in an initial state, the screen is not displayed. Non-uniformity can be prevented.

As a modification of the eighth embodiment, when the potential of the first power supply line 213 is higher than that of the second power supply line 215, the current TFT 223 is a p-channel type, and the fourth correction TFT is an n-channel type. The gate electrode may be connected to an 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 second power supply 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. Therefore, the gate voltage of the current TFT 223 decreases, the resistance between the source electrode and the drain electrode decreases, and the correction is automatically performed.

Further, as another modified example 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 replaced with the n-channel type current TFT 223. Is a p-channel type, its gate electrode is connected to the electrode on the first power supply line side of the organic EL element 224, and its source and drain electrodes are connected between the storage capacitor 222 and the second power supply line 215. Is 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. Therefore, the gate voltage of the current TFT 223 increases, the resistance between the source electrode and the drain electrode decreases, and the correction is automatically performed.

Further, as another modified example of the eighth embodiment, when the potential of the first power supply line 213 is lower than the potential of the second power supply line 215, the current TFT 223 is of a p-channel type, and the fourth correction TFT 234 is It is configured to be an n-channel type, with its gate electrode connected to the electrode on the first power supply line side of the organic EL element 224, and its source and drain electrodes connected between the storage capacitor 222 and the second power supply line 215. Is 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. Therefore, the gate voltage of the current TFT 223 decreases, the resistance between the source electrode and the drain electrode decreases, and the correction is automatically performed.

In the present embodiment, preferably, the switching TFT 221, the current TFT 223, and the fourth correction TFT 234 are formed on the same TFT array substrate by the same manufacturing process. According to this configuration, it is possible to correct a 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 Embodiment 9 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 description thereof will be omitted.

In FIG. 15, the first correction thin-film photodiode 241 provided in the pixel circuit of this embodiment has a property of being reduced in 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 amount of light emission.

More specifically, when the potential of the first feed line 213 is higher than the potential of the second feed 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. Therefore, the gate voltage of the current TFT 223 decreases, and the resistance between the source electrode and the drain electrode decreases.

Therefore, according to the ninth embodiment, even if the light emission amount of the organic EL element 224 decreases due to the deterioration over time, the decrease in the light emission amount of the organic EL element 224 is corrected by the increase in the resistance of the first thin-film photodiode 241 for correction. It becomes possible. Further, since such correction is performed on a pixel-by-pixel basis, when time-dependent deterioration occurs with variation among a plurality of pixels, or when there is variation in light emission characteristics among a plurality of organic EL elements in an 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. .

Further, as another modified example of the ninth embodiment, when the potential of the first power supply line 213 is lower than the potential of the second power supply line 215, the current TFT 223 is of an n-channel type, and 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 further provided so that its source electrode and 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 decreases, the resistance of the first correction thin-film photodiode 241 increases, and further, the gate voltage of the current TFT 223 increases, and the voltage between the source electrode and the drain electrode thereof increases. The resistance is reduced and the correction is made automatically.

In the present embodiment, preferably, the switching TFT 221, the current TFT 223, and the first correction thin-film photodiode 241 are formed on the same TFT array substrate by the same manufacturing process. According to this configuration, it is possible to correct a 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 Embodiment 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 description thereof will be omitted.

In FIG. 16, the second correction thin-film photodiode 242 provided in the pixel circuit of this embodiment has a property of being reduced in 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 at both ends of the organic EL element 224 and the amount of light emission.
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 type current TFT 223 as shown in FIG. The 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. Therefore, the gate voltage of the current TFT 223 is increased, and the resistance between the source electrode and the drain electrode is reduced.

Therefore, according to the tenth embodiment, even if the light emission amount of the organic EL element 224 decreases due to the deterioration over time, the decrease in the light emission amount of the organic EL element 224 is corrected by the increase in the resistance of the second correction thin film photodiode 242. It becomes possible. Further, since such correction is performed on a pixel-by-pixel basis, when time-dependent deterioration occurs with variation among a plurality of pixels, or when variation in light emission characteristics between a plurality of organic EL elements exists in an 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 so that its source electrode and drain electrode are connected between the storage capacitor and the second power supply line 215. .

Further, as another modified example of the tenth embodiment, when the potential of the first power supply line 213 is lower than the potential of the second power supply line 215, the current TFT 223 is of a p-channel type, and The diode 242 may be configured to be connected between the storage capacitor 222 and the second power supply line 215. In this case, a sixth correction TFT (not shown) may be further provided such that its source electrode and drain electrode are connected between the storage capacitor 222 and the second power supply line 215. According to this configuration, when the amount of light emitted from the organic EL element 224 decreases, the resistance of the second correction thin-film photodiode 242 increases, and further, the gate voltage of the current TFT 223 decreases to reduce the voltage between the source electrode and the drain electrode. The resistance is reduced and the correction is made automatically.

In the present embodiment, preferably, the switching TFT 221, the current TFT 223, and the second thin-film photodiode 242 for correction are formed on the same TFT array substrate by the same manufacturing process. According to this configuration, it is possible to correct a 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 'provided in the display device. In FIG. 17, a pixel circuit for only one pixel is shown in the display area 115, but a similar pixel circuit is provided for each pixel in practice.

In FIG. 17, a display device 200a according to the present embodiment includes a common line configured to be capable of separately supplying a power signal to each of a plurality of common lines 133 in addition to the scanning line driving circuit 11 and the signal line driving circuit 12. The drive circuit 13 ′, the common line power supply 205 for supplying power to the common line drive circuit 13 ′, and the measured current amount IDmn (m) for each of the plurality of pixels 10 in the display area 15 measured by the current measurement circuit 16 ′. : A signal line number (1 to M), n: a frame memory 207 for storing signal line numbers (1 to N)), and a deterioration correction circuit interposed between the image signal source 208 and the signal line drive circuit 12. 209 are further provided. 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 the driving current Id due to the deterioration over time in each of the plurality of pixels 10. After the correction for each pixel 10 according to the measured current amount IDn thus obtained, the correction value is output to the signal line drive circuit 12. At least one of the common line driving circuit 13 ′, the common line power supply 205, the current measuring circuit 16 ′, the frame memory 207, and the deterioration correction circuit 209 is formed on a TFT array substrate having a display area 115 in the center. (See FIG. 1), or 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 changeover switch 301, a power supply signal of a predetermined potential is collectively supplied to the plurality of common lines 133 via the wiring 310 during a normal display operation (that is, the potentials of all the common lines 133 are equalized). 2), the switch is made to the side of the power supply line 310 connected to the common line power supply 205 under the control of the controller. On the other hand, the changeover switch 301 supplies the measurement power supply signal to the plurality of common lines 133 via the wiring 320 when performing the correction for the aging deterioration (adjustment of the voltage of the power supply signal supplied to each common line 133) as described later. Are sequentially switched to the side of the wiring 320 connected to the current amount measuring circuit 16 ′ via the transmission switch 303 so as to be sequentially supplied. The power supply signal for measurement may be supplied from a power supply incorporated 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 a power supply signal for measurement to the changeover switch 301 in accordance with a transfer signal sequentially output from the shift register 302 when correcting the deterioration with time, and the changeover switch 301 transmits this signal via the common line 133. To each pixel circuit. At this time, the shift register 302 is configured to sequentially output transfer signals 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 correcting for the deterioration with time, a power supply for measurement is sequentially supplied to a plurality of common lines 133 via transmission switches 303 which can be transmitted according to transfer signals sequentially output from the shift register 302. A signal is provided. Then, the current amount of the measurement power supply signal 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, the power supply signal is supplied to each pixel 10 from the pixel row supplied from one common line 133 for each pixel to which the scanning signal is supplied. Then, a power supply signal for measurement flows as a drive current to the organic EL element 224 via the current TFT 223. In other words, by sequentially supplying the measurement power supply signal to the common line 133 at the timing of the transfer signal by the shift register 302 while sequentially supplying the scan signal from the scan line drive circuit 11, the drive current Id for each pixel 10 is reduced. The quantity is measured by the quantity measuring circuit 16 'in a dot-sequential manner. Then, the measured current amount IDmn is stored in the frame memory 207.

Next, when a normal display operation is performed, 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 time-dependent deterioration according to the degree of the time-dependent deterioration determined based on the current amount IDmn of each pixel 10 stored in the frame memory 207 (ie, the degree of decrease in the measured driving 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 reduction, 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 change in the gradation level by the deterioration correction circuit 209. When performing a normal display operation, 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. Further, in the present embodiment, 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, 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 is, 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 the TFT-OELD according to Example 12, and FIG. 20 is a cross-sectional view of a pixel circuit provided in each pixel of the display device. Although a circuit for only one pixel is shown in the display area 115 in FIG. 19, a similar circuit is provided for each pixel in practice. In FIG. 19, the same components as those of the eleventh embodiment shown in FIG. 17 are denoted by the same reference numerals, and the description thereof will be omitted.

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

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 for forming 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 inspection light beam 104 so that a photo-excitation current flows when light enters the PIN junction from the organic EL element 224 via the interlayer insulating films 251 to 253. It is constituted so that it may be supplied from. The gate and the scanning line 131 of each TFT are formed of a metal film such as Ta or a low-resistance polysilicon film, and the signal line 132, the common line 133, and the analysis light 104 are formed of a low-resistance metal film such as Al. It is configured. Then, a driving 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 EL element 224 via the current TFT 223. If the counter electrode 105 is made of a transparent material such as ITO, the upper surface of the display device 200a in FIG. 20 can be used as the display surface. On the other hand, if the counter electrode 105 is made of a light-reflective or light-blocking metal material such as Al or the like, the lower surface in FIG. 20 of the display device 200a can be used as a 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, at the time of performing the correction processing for the deterioration over time, the scanning line driving circuit 11 and the signal line driving circuit 12 supply a scanning signal and a data signal for displaying a predetermined pattern, thereby causing the organic EL element 224 to emit light. . Then, since the counter electrode 105 is a material mainly composed of Al 2, light is reflected and emitted downward through the pixel electrode 141. At this time, since the PIN diode 110 that is reverse-biased by the light beam 104 is disposed in a part of the optical path, an optical excitation current is generated in the PIN diode 110 and reaches the light beam driving circuit 204 through the light beam 104. . Like the common line driving circuit 203 in the eleventh embodiment, the light detection driving circuit 204 includes a plurality of transmission switches, sequentially supplies reverse bias power to the PIN diode 110 from the light detection light 204 to the PIN diode 110, and performs measurement. The measurement current is sequentially supplied to the current measurement circuit 16 ″. Then, as in the eleventh embodiment, the current measurement circuit 16 ″ measures such a 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 in accordance with the increase in the measurement current amount IDmn 'of the measurement current. 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 in the eleventh embodiment is performed.

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

Next, in a state where 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 beam driving circuit 204, the current measurement circuit 16 ″, and the like in the above-described correction processing. The deterioration correction circuit 209 is based on the light emission characteristic curve 405. , And an appropriate signal conversion curve 404. Thereafter, during a normal display period, the signal level of the gradation levels D1, D2,. Adjustment for each gradation level is performed so that the image signals of V1, V2,..., V6 are output from the signal line driving circuit 12. Therefore, in each pixel 10, according to the emission characteristic curve 405 after deterioration, The same light emission amount can be obtained after the deterioration, and in this embodiment, the deterioration of the threshold voltage for the light emission of the organic EL element 224 is also considered.

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

In the present embodiment, the light emission amount is measured for all the pixels 10 and the measured value is stored in the frame memory 207. However, for some of the extracted pixels 10, May be measured, and the measured value may be stored. Further, here, 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.

Also, in the present embodiment, the PIN diode 110 is used as the monitoring light receiving element for generating the photoexcitation current, but a semiconductor element such as a field effect transistor may be used. At this time, as the potential applied to the gate electrode of the field effect transistor, a potential that effectively generates a photoexcitation current is selected. Further, in order for the light emitted from the organic EL element 224 to reach the channel, a suitable structure such as a top gate type, a forward stagger type, an inverted stagger type, a channel etch type or a channel stopper type is used, and the gate electrode is also formed of ITO. May be formed. Furthermore, in this embodiment, preferably, a TFT formed in each drive circuit or each pixel circuit and a PIN diode as a semiconductor element for generating a photoexcitation current are formed in the same step. This is advantageous because a separate step for forming the PIN diode is not required.

FIG. 22 shows a method of correcting deterioration in a display device including the TFT-OELD according to Embodiment 13 of the present invention. The hardware configuration of the display device according to the thirteenth embodiment is the same as that of the eleventh or twelfth embodiment, and a description thereof will be omitted.

In the thirteenth embodiment, the method of setting the signal conversion curve 404 based on the emission characteristic curve 405 obtained by the emission amount measurement in the deterioration correction circuit 209 described with reference to FIG. In the thirteenth embodiment, the adjustment of the voltage value of the data signal is performed by converting one predetermined signal level to another predetermined signal level. That is, in FIG. 21B corresponding to the case where the organic EL element 224 has deteriorated and the light emission amount has decreased, the signal levels V1, V2,... A signal conversion curve 404 for the light emission characteristic curve 405 is set by selecting from among discrete potentials determined in advance due to restrictions of a power supply or the like. As a result, although the linearity of the light emission amount is impaired, since the gradation inversion does not occur, a good gradation can be obtained with the naked eye.

As described above, according to the thirteenth embodiment, the signal line drive circuit 12 can perform correction for a decrease in the amount of light emission due to deterioration with time, using a power supply having a limited type of potential.

In the first to thirteenth embodiments, the pixel circuit is provided with the switching TFT. For example, the scanning signal is directly supplied from the scanning line to the gate of the driving TFT and the data signal is supplied to the driving TFT. The data signal may be supplied to the organic EL element via the source and drain of the driving TFT by directly supplying the signal from the signal line to the source to drive the organic EL element. That is, also in this case, it is possible to correct a decrease in the drive current and the light emission amount due to the deterioration over time in the organic EL element and the drive TFT provided in each pixel by the present invention. The switching TFT provided in each pixel circuit may be formed 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. Is also good.

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

First, FIG. 23 shows a schematic configuration of an electronic apparatus including the display device as described above.

In FIG. 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 driving circuit 1004 in this embodiment. Therefore, the driver circuit 1004 may be mounted on the TFT array substrate included in the display panel 1006, and the display information processing circuit 1002 and the like may be mounted. Alternatively, the driving circuit 1004 may be provided externally to the TFT array substrate on which the display panel 1006 is mounted.

The display information output source 1000 includes a read only memory (ROM), a random access memory (RAM), a memory such as an optical disk device, a tuning circuit for tuning and outputting 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 includes various well-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. Digital signals are 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 a predetermined power to each of the above-described circuits.

FIGS. 24 to 25 show specific examples of the electronic device configured as described above.

In FIG. 24, a laptop personal computer (PC) 1200 for multimedia, which is another example of electronic equipment, 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 in which the drive circuit 1004 and the display information processing circuit 1002 are not mounted, a TCP in which the IC 1324 including the drive circuit 1004 and 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 TFT array substrate 1 via an anisotropic conductive film provided on the periphery of the TFT array substrate 1 to produce, sell, use, etc. as a display panel. It is possible.

In addition to the electronic devices described with reference to FIGS. 24 to 25, a television, a viewfinder type or a monitor direct-view type video tape recorder, a car navigation device, an electronic organizer, a calculator, a word processor, an engineering workstation (EWS) ), A mobile phone, a videophone, a POS terminal, a device having a touch panel, and the like are examples of the electronic apparatus 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 display over time in current-driven light-emitting elements such as organic EL elements and driving elements such as current TFTs. Various electronic devices 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 an organic EL element, an inorganic EL element, a light-emitting polymer, and an LED, and a driving element such as a TFT that drives the light-emitting element. In addition, the pixel circuit according to the present invention can be used for various active matrix drive type display devices. Further, an electronic device according to the present invention is configured using such a pixel circuit or a display device, and can be used as an electronic device capable of displaying high-quality images for a long time.

FIG. 2 is a block diagram illustrating a basic overall configuration of a display device common to each embodiment of the present invention. FIG. 2 is a plan view of one pixel of the display device of FIG. 1. FIG. 1 is a block diagram of a display device according to a first embodiment of the present invention. FIG. 3 is a characteristic diagram illustrating a relationship between a gradation level (D) of an image signal, a data signal voltage (Vsig), and a driving current (Id) and a method of correcting deterioration with time in Embodiment 1. FIG. 9 is a block diagram of a modification of the first embodiment. FIG. 13 is a block diagram of another modification of the first embodiment. FIG. 7 is a characteristic diagram illustrating a relationship between a data signal (V sig) and a driving current (Id) and a method of correcting temporal deterioration in a modification of FIG. It is a block diagram of a display of Example 2 of the present invention. It is a block diagram of a display of Example 3 of the present invention. It is a block diagram of a display of Example 4 of the present invention. FIG. 11 is an equivalent circuit diagram of one pixel of a display device according to a fifth embodiment of the present invention. FIG. 13 is an equivalent circuit diagram of one pixel of a display device according to a sixth embodiment of the present invention. FIG. 14 is an equivalent circuit diagram of one pixel of a display device according to Example 7 of the present invention. FIG. 14 is an equivalent circuit diagram of one pixel of a display device according to an eighth embodiment of the present invention. FIG. 15 is an equivalent circuit diagram of one pixel of a display device according to a ninth embodiment of the present invention. FIG. 21 is an equivalent circuit diagram of one pixel of a display device according to a tenth embodiment of the present invention. FIG. 21 is a block diagram showing an entire configuration of a display device according to Example 11 of the present invention, including a circuit diagram of one pixel. FIG. 34 is a circuit diagram of a common line driving circuit included in the display device according to the eleventh embodiment. FIG. 21 is a block diagram illustrating an entire configuration of a display device according to Example 12 of the present invention, including a circuit diagram of one pixel. FIG. 39 is a cross-sectional view of a TFT-OELD part included in the display device of Example 12. FIG. 22 is a characteristic diagram illustrating a method for correcting temporal deterioration in the display device of Example 12. FIG. 18 is a characteristic diagram illustrating a method for correcting temporal deterioration in a display device according to Example 13 of the present invention. 1 is a block diagram illustrating a schematic configuration of an electronic device according to an embodiment of the present invention. FIG. 18 is a front view illustrating a personal computer as an example of an electronic apparatus. FIG. 13 is a perspective view illustrating a liquid crystal device using TCP as another example of the electronic apparatus.

Claims (12)

A display device including a plurality of pixels each including a light-emitting element,
Including a current amount measurement unit that measures the amount of drive current flowing through the light emitting element,
Adjusting the current amount of the drive current of the light emitting element based on the result obtained by the current amount measurement unit,
A display device characterized by the above-mentioned. The display device according to claim 1,
Adjusting the current amount of the drive current by adjusting a power supply voltage supplied to the light emitting element;
A display device characterized by the above-mentioned. The display device according to claim 1,
In addition, including multiple signal lines,
Each of the plurality of pixels includes a driving element that controls the driving current flowing through the light emitting element according to a data signal supplied via a corresponding signal line of the plurality of signal lines,
Adjusting the current amount of the drive current by adjusting the data signal,
A display device characterized by the above-mentioned. The display device according to claim 3,
The driving element is a transistor whose conductance between source and drain is controlled by the data signal,
A display device characterized by the above-mentioned. The display device according to claim 1, wherein
The adjustment of the current amount of the drive current performed based on the result obtained by the current amount measurement unit is performed in a non-display period prior to a display period,
A display device characterized by the above-mentioned. The display device according to claim 2,
The adjustment of the power supply voltage performed based on the result obtained by the current amount measurement unit is performed in a non-display period prior to a display period,
A display device characterized by the above-mentioned. The display device according to claim 3,
The adjustment of the data signal performed based on the result obtained by the current amount measurement unit is performed in a non-display period prior to a display period,
A display device characterized by the above-mentioned. A display device including a plurality of pixels each including a light-emitting element,
A light emitting element for monitoring;
A current amount measuring unit that measures the amount of drive current flowing through the monitor light emitting element,
Adjusting the drive current flowing through the light emitting element based on the result obtained by the current amount measurement unit,
A display device characterized by the above-mentioned. A display device including a plurality of signal lines and a plurality of pixels,
Each of the plurality of pixels includes:
The light emitting element;
A drive element that controls a drive current flowing through the light-emitting element in accordance with a data signal supplied via a corresponding signal line of the plurality of signal lines,
A current amount measurement unit that measures the amount of drive current flowing through the light emitting element,
Adjusting the data signal based on the result obtained by the current amount measurement unit,
A display device characterized by the above-mentioned. The display device according to claim 8,
The adjustment of the current amount of the drive current performed based on the result obtained by the current amount measurement unit is performed in a non-display period prior to a display period,
A display device characterized by the above-mentioned. The display device according to claim 9,
The adjustment of the data signal performed based on the result obtained by the current amount measurement unit is performed in a non-display period prior to a display period,
A display device characterized by the above-mentioned. An electronic apparatus comprising the display device according to claim 1.

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