KR102486399B1 - Pixel circuit and organic light emitting display device having the same - Google Patents

Abstract

The pixel circuit includes an organic light emitting diode having a cathode connected to a second power supply, a scan switch having a gate electrode to which a scan signal is applied, a first electrode to which a data voltage is applied, and a second electrode connected to a first node, and a first node. A driving transistor including a gate electrode connected to, a first electrode connected to a second node, and a second electrode connected to a third node corresponding to the anode of the organic light emitting diode, a gate electrode to which a first sensing control signal is applied, A first sensing switch having a first electrode connected to a first node and a second electrode connected to a second node, a gate electrode to which a second sensing control signal is applied, a first electrode connected to a third node, and a second electrode connected to a second node. A second sensing switch having a second electrode connected to a power source, a gate electrode to which a light emission control signal is applied, a light emission control switch having a first electrode connected to a first power source and a second electrode connected to a second node, and a storage capacitor connected between the first node and the third node. The pixel circuit is driven in an image display mode and a sensing mode.

Description

Pixel circuit and organic light emitting display device including the same

The present invention relates to a display device, and more particularly, to a pixel circuit capable of detecting deterioration and an organic light emitting display device including the same.

An organic light emitting display device is a device that displays images using organic light emitting diodes. In the organic light emitting diode display, differences in characteristics such as threshold voltage and mobility of driving transistors occur for each pixel due to process variation, etc., and luminance variation and afterimages occur between pixels due to deterioration of the organic light emitting diode. .

In a conventional organic light emitting display device, a reference voltage is applied to a plurality of pixel circuits through sensing lines (or reference lines) arranged in units of pixel circuits, and based on individual gate signals applied corresponding to pixel rows, Measure the sensing current. Accordingly, since a buffer driver for the sensing line and a driver circuit for generating the gate signals are required inside the sensing line and the data driver, the area and complexity of the system and the driver greatly increase. Also, it is impossible to measure the voltage and current of each of the pixel circuits or each of the organic light emitting diodes, making it impossible to detect deterioration of the organic light emitting diodes.

One object of the present invention is to provide a pixel circuit outputting a sensing current for detecting deterioration of a driving transistor and/or an organic light emitting diode in a sensing mode using a global gate signal.

Another object of the present invention is to provide an organic light emitting display device including the pixel circuit.

However, the object of the present invention is not limited to the above-mentioned objects, and may be expanded in various ways without departing from the spirit and scope of the present invention.

In order to achieve one object of the present invention, a pixel circuit according to embodiments of the present invention includes an organic light emitting diode having a cathode connected to a second power supply, a gate electrode to which a scan signal is applied, a first electrode to which a data voltage is applied, and a second power source. A scan switch having a second electrode connected to a first node, a gate electrode connected to the first node, a first electrode connected to the second node, and a third node connected to the third node corresponding to the anode of the organic light emitting diode. A first sensing switch having a driving transistor including two electrodes, a gate electrode to which a first sensing control signal is applied, a first electrode connected to the first node, and a second electrode connected to the second node; A second sensing switch having a gate electrode to which a sensing control signal is applied, a first electrode connected to the third node, and a second electrode connected to the second power source, a gate electrode to which an emission control signal is applied, and a first power source A light emitting control switch having a first electrode connected to and a second electrode connected to the second node, and a storage capacitor connected between the first node and the third node, in an image display mode and a sensing mode. can be driven

According to an embodiment, each of the first sensing control signal and the emission control signal may correspond to a global gate signal.

According to an embodiment, the second sensing control signal corresponds to the scan signal, and the scan switch and the second sensing switch may be simultaneously controlled. When the second sensing control signal corresponds to the scan signal, the image display mode may operate in a simultaneous light emitting mode or a sequential light emitting mode.

According to an embodiment, in the sensing mode, the first sensing switch may maintain a turned-on state, and the emission control switch may maintain a turned-off state.

According to an embodiment, in the sensing mode, the first sensing control signal may have a logic high level and the emission control signal may have a logic low level.

According to an embodiment, in the sensing mode, when the scan switch and the second sensing switch are turned on, a sensing current flowing through a data line may be detected based on a gate-source voltage of the driving transistor.

According to an embodiment, in the sequential light emission mode, the first sensing switch may maintain a turned-off state, and the light emission control switch may maintain a turned-on state.

According to an exemplary embodiment, the simultaneous emission mode may include a writing period and a simultaneous emission period. The light emitting control switch may be turned off in the writing period and turned on in the simultaneous light emitting period, and the first sensing switch may maintain a turned off state in the simultaneous light emitting mode.

According to an embodiment, each of the first sensing control signal, the second sensing control signal, and the emission control signal may correspond to a global gate signal. The sensing mode is divided into a first sensing mode for detecting a deterioration characteristic of the driving transistor and a second sensing mode for detecting a deterioration characteristic of the organic light emitting diode, and the image display mode may correspond to a simultaneous emission mode.

According to an embodiment, in the first sensing mode, the first sensing switch and the second sensing switch may maintain a turned-on state, and the emission control switch may maintain a turned-off state.

According to an embodiment, in the first sensing mode, the first and second sensing control signals may have a logic high level and the emission control signal may have a logic low level.

According to an embodiment, in the second sensing mode, the first sensing switch may maintain a turned-on state, and the second sensing switch and the emission control switch may maintain a turned-off state.

According to an embodiment, in the second sensing mode, the first sensing control signal may have a logic high level, and the second sensing control signal and the emission control signal may have a logic low level. .

According to an embodiment, in the second sensing mode, when the scan switch is turned on, a sensing current flowing through the organic light emitting diode may be detected through a data line.

In order to achieve one object of the present invention, an organic light emitting display device according to embodiments of the present invention is driven in an image display mode or a sensing mode, and includes a scan line, a data line, a first sensing control line, a second sensing control line, and A display panel including a plurality of pixel circuits each connected to a light emitting control line, a scan driver providing a scan signal to the scan line, providing a first sensing control signal to the first sensing control line, and providing a scan signal to the light emitting control line. A global gate driver providing a light emission control signal, a data driver providing a data voltage to the data line based on image data, and analyzing a sensing current flowing through the data line to each of the pixel circuits to obtain the data voltage or the image voltage. It may include a controller that compensates for data and a power source that provides first power and second power having a voltage level lower than that of the first power to the display panel. Each of the plurality of pixel circuits includes an organic light emitting diode having a cathode connected to the second power supply, a gate electrode to which the scan signal is applied, a first electrode to which the data voltage is applied, and a second electrode connected to a first node. A driving transistor including a scan switch including a scan switch, a gate electrode connected to the first node, a first electrode connected to a second node, and a second electrode connected to a third node corresponding to the anode of the organic light emitting diode; A first sensing switch having a gate electrode connected to the first sensing control line to receive the first sensing control signal, a first electrode connected to the first node, and a second electrode connected to the second node; A second sensing switch having a gate electrode connected to the second sensing control line to receive the second sensing control signal, a first electrode connected to the third node, and a second electrode connected to the second power source; A light emitting control switch including a gate electrode connected to the light emitting control line to which the light emitting control signal is applied, a first electrode connected to a first power source, and a second electrode connected to the second node, and the first node and the light emitting control switch. A storage capacitor connected between the third nodes may be included.

According to an embodiment, the first sensing control signal and the emission control signal may each correspond to a global gate signal, and the second sensing control signal may correspond to the scan signal. The image display mode may operate in a simultaneous light emission mode or a sequential light emission mode.

According to an embodiment, in the sensing mode, the first sensing switch maintains a turn-on state, the emission control switch maintains a turn-off state, and the control unit degrades the driving transistor based on the sensing current. can be analyzed.

According to an embodiment, the global gate driver may provide the second sensing signal to the second sensing control line. Each of the first sensing control signal, the second sensing control signal, and the emission control signal may correspond to a global gate signal. The sensing mode may include a first sensing mode for detecting a deterioration characteristic of the driving transistor and a second sensing mode for detecting a deterioration characteristic of the organic light emitting diode, and the image display mode may operate as a simultaneous emission mode.

According to an embodiment, in the first sensing mode, the first sensing switch and the second sensing switch may maintain a turned-on state, and the emission control switch may maintain a turned-off state.

According to an embodiment, in the second sensing mode, the first sensing switch may maintain a turned-on state, and the second sensing switch and the emission control switch may maintain a turned-off state. When the scan switch is turned on, the sensing current flowing through the organic light emitting diode may be detected.

In the pixel circuit and the organic light emitting diode display including the pixel circuit according to embodiments of the present invention, components such as a separate sensing line and a gate driver for detecting deterioration of the pixel circuit (or compensating for external deterioration) may be removed. In addition, signals controlling image display and sensing operations are all global gate signals (eg, at least one of a first sensing control signal, a second sensing control signal, and an emission control signal) that can be output from a simple circuit configuration. Correspondingly, the area and circuit complexity of the scan driver and the global gate driver may be reduced. Thus, yield and reliability of the organic light emitting display device may be increased.

Furthermore, simultaneous light emission, sequential light emission, driving transistor sensing, and organic light emitting diode sensing can be easily performed through the control of the global gate signals.

However, the effects of the present invention are not limited to the above-described effects, and may be variously extended within a range that does not deviate from the spirit and scope of the present invention.

1 is a block diagram illustrating an organic light emitting display device according to example embodiments.
FIG. 2 is a circuit diagram illustrating an example of a pixel circuit included in the organic light emitting diode display of FIG. 1 .
FIG. 3 is a timing diagram illustrating an example of an operation of the organic light emitting diode display of FIG. 1 .
FIG. 4 is a block diagram illustrating an example of the organic light emitting display device of FIG. 1 .
FIG. 5 is a circuit diagram illustrating an example of a pixel circuit included in the organic light emitting diode display of FIG. 4 .
6 is a timing diagram for explaining an example of an operation of the organic light emitting diode display of FIG. 4 .
FIG. 7 is a timing diagram for explaining another example of an operation of the organic light emitting diode display of FIG. 4 .
FIG. 8 is a diagram for explaining an example of an operation of the organic light emitting diode display of FIG. 4 .
9 is a block diagram illustrating an electronic device according to embodiments of the present invention.
10A is a diagram illustrating an example in which the electronic device of FIG. 9 is implemented as a television.
10B is a diagram illustrating an example in which the electronic device of FIG. 9 is implemented as a smart phone.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in more detail. The same reference numerals are used for the same components in the drawings, and redundant descriptions of the same components are omitted.

1 is a block diagram illustrating an organic light emitting display device according to example embodiments.

Referring to FIG. 1 , the organic light emitting diode display 100 includes a display panel 110, a scan driver 120, a global gate driver 130, a data driver 140, a controller 150, and a power supply 160. can do.

The organic light emitting display device 100 may operate in an image display mode for displaying an image and a sensing mode. In one embodiment, the image display mode may operate in a sequential light emission mode or a simultaneous light emission mode.

The display panel 110 includes a plurality of scan lines SL1 to SLn, a plurality of first sensing control lines GL11 to GL1n, a plurality of emission control lines GL21 to GL2n, and a plurality of data lines DL1. to DLm) and a plurality of scan lines SL1 to SLn, a plurality of first sensing control lines GL11 to GL1n, a plurality of emission control lines GL21 to GL2n, and a plurality of data lines DL1 to DLm. ) may include a plurality of pixel circuits 10 each connected to (provided that n and m are integers greater than or equal to 2).

Each of the pixel circuits 10 includes an organic light emitting diode having a cathode connected to the second power supply, a gate electrode to which a scan signal is applied, a first electrode to which the data voltage is applied, and a second electrode connected to a first node. A driving transistor including a scan switch, a gate electrode connected to the first node, a first electrode connected to a second node, and a second electrode connected to a third node corresponding to the anode of the organic light emitting diode, a first A first sensing switch having a gate electrode to which a sensing control signal is applied, a first electrode connected to the first node, and a second electrode connected to the second node, a gate electrode to which a second sensing control signal is applied, the A second sensing switch having a first electrode connected to a third node and a second electrode connected to the second power source, a gate electrode to which a light emission control signal is applied, a first electrode connected to the first power source, and the second sensing switch. A light emitting control switch having a second electrode connected to a node, and a storage capacitor connected between the first node and the third node.

The scan driver 120 may sequentially provide the scan signal to the scan lines SL1 to SLn based on the scan control signal CON1. Accordingly, data voltages may be sequentially written to pixel rows corresponding to the scan lines SL1 to SLn, or pixel deterioration sensing may be sequentially performed. In one embodiment, the scan signal may correspond to the second sensing control signal. That is, the scan signal may be simultaneously provided to the gate electrode of the scan transistor and the gate electrode of the second sensing switch. However, this is just an example, and in another embodiment, the second sensing control signal may correspond to a predetermined global gate signal output from the global gate driver 130 .

The global gate driver 130 provides the first sensing control signal to the first sensing control lines GL11 to GL1n based on the gate control signal CON2 and emits the light emission to the light emission control lines FL21 to GL2n. A control signal may be provided. Each of the first sensing control signal and the emission control signal may correspond to a global gate signal. That is, the first sensing control signal may be commonly provided to all pixel circuits 10 included in the display panel 110, and the emission control signal may also be provided to all pixel circuits 10 included in the display panel 110. ) can be provided in common. According to logic levels of the first sensing control signal and the light emission control signal, the pixel circuits 10 may sequentially or simultaneously emit light. In one embodiment, the global gate driver 130 may be physically included in the scan driver 120 .

The data driver 140 may generate data voltages based on the data driving control signal CON3 including image data. The data voltage may be provided to data lines DL1 to DLm. In the image display mode, the data voltage may correspond to a displayed image. In the sensing mode, the data voltage may correspond to a preset voltage level. In one embodiment, the data driver 140 may include a sensing block that detects or reads out a sensing current flowing through a data line in the sensing mode.

The controller 150 may compensate for the data voltage or the image data by analyzing the sensing current flowing in each of the pixel circuits 10 through each of the data lines DL1 to DLm. Accordingly, deterioration of the driving transistor and/or deterioration of the organic light emitting diode may be compensated for. The compensated image data or the compensated data voltage may be provided to the data driver 140 . In one embodiment, the controller 150 may be physically included in the data driver 140 . In one embodiment, the controller 150 may control operations of the scan driver 120 , the global gate driver 130 , and the data driver 140 .

The power supply unit 160 may provide the first power source ELVDD and the second power source ELVSS having a lower voltage level than the first power source ELVDD to the display panel 110 . In one embodiment, the second power source ELVSS may correspond to the ground voltage.

As described above, in the organic light emitting display device 100 according to the exemplary embodiments of the present invention, components such as a separate sensing line and a gate driver for detecting deterioration of the pixel circuit 10 (or compensating for external deterioration) may be removed. can

In addition, since signals controlling image display and sensing operations all correspond to global gate signals that can be output from a simple circuit configuration, the area and circuit complexity of the scan driver 120 and the global gate driver 130 can be reduced. Thus, yield and reliability of the organic light emitting display device 100 may be increased.

FIG. 2 is a circuit diagram illustrating an example of a pixel circuit included in the organic light emitting diode display of FIG. 1 .

Referring to FIG. 2 , the pixel circuit 10 includes an organic light emitting diode (EL), a scan switch (SW1), a driving transistor (TD), a first sensing switch (SW2), a second sensing switch (SW3), and an emission control switch. (SW4) and a storage capacitor (CST).

In one embodiment, the scan switch SW1 , the driving transistor TD, the first sensing switch SW2 , the second sensing switch SW3 , and the light emitting control switch SW4 are N-channel metal oxide semiconductor (NMOS); NMOS) transistors. The NMOS transistors may be formed of an oxide TFT, an amorphos-silicon (a-Si TFT) transistor, or a poly-silicon (Poly-Si TFT) transistor. However, this is exemplary, and the scan switch SW1 , the driving transistor TD, the first sensing switch SW2 , the second sensing switch SW3 , and the light emitting control switch SW4 are PMOS (P-channel Metal Oxide Semiconductor (PMOS) transistors may also be implemented.

In one embodiment, the pixel circuit 10 may be driven in an image display mode and a sensing mode. In the image display mode, the data voltage VDATA[j] corresponding to the image gray level (or luminance) may be transmitted to the pixel circuit 10 through the data line DLj. The image display mode may be driven in one of a sequential emission mode in which light is emitted sequentially along scan lines and a simultaneous emission mode in which all pixel circuits simultaneously emit light. In the sensing mode, the data voltage VDATA[j] corresponding to the preset reference voltage may be transmitted to the pixel circuit 10 through the data line DLj. In the sensing mode, a current flowing through the driving transistor TD or a current flowing through the organic light emitting diode EL may be detected.

The organic light emitting diode EL may include a cathode connected to the second power source ELVSS and an anode connected to the second electrode (ie, the source electrode) of the driving transistor TD.

The scan switch SW1 may include a gate electrode to which the scan signal SCAN[k] is applied, a first electrode connected to the first node N1, and a second electrode connected to the second node N2. . The scan switch SW1 may transmit the data voltage VDATA[j] to the first node N1 in response to the scan signal SCAN[k].

The driving transistor TD is connected to a gate electrode connected to the first node N1, a first electrode connected to the second node N2, and a third node N30 corresponding to the anode of the organic light emitting diode EL. The first electrode of the driving transistor TD may be a drain electrode, and the second electrode may be a source electrode. In one embodiment, the driving transistor TD may include a storage capacitor ( A driving current corresponding to the voltage charged in CST) may be generated.

The first sensing switch SW2 may include a gate electrode to which the first sensing control signal G_SEN is applied, a first electrode connected to the first node N1, and a second electrode connected to the second node N2. can In one embodiment, the first sensing control signal G_SEN may be a global gate signal commonly applied to the entire display panel. In the image display mode, the first sensing switch SW2 may maintain a turned off state based on the first sensing control signal G_SEN having a logic low level. Also, in the sensing mode, the first sensing switch SW2 may be turned on based on the first sensing control signal G_SEN having a logic high level. Accordingly, in the sensing mode, the driving transistor TD may have a diode-connected form.

The second sensing switch SW3 may include a gate electrode to which the second sensing control signal is applied, a first electrode connected to the third node N3, and a second electrode connected to the second power source ELVSS. In this embodiment, the second sensing control signal may correspond to the scan signal SCAN[k]. Accordingly, the scan switch SW1 and the second sensing switch SW3 may be simultaneously controlled by the scan signal SCAN[k]. In one embodiment, when the organic light emitting diode EL emits light, the second sensing switch SW3 may be turned off. In addition, when the second sensing switch SW3 is turned on in the sensing mode for sensing deterioration of the driving transistor TD, the second electrode of the driving transistor TD is connected to the second power source ELVSS (eg, ground voltage). Accordingly, the degree of deterioration (eg, change in threshold voltage, change in mobility, etc.) of the driving transistor TD may be detected in the sensing mode.

The emission control switch SW4 may include a gate electrode to which the emission control signal G_EM is applied, a first electrode connected to the first power source ELVDD, and a second electrode connected to the second node N2. In an exemplary embodiment, the emission control signal G_EM may be a global gate signal commonly applied to the entire display panel. In the image display mode, the light emission control switch SW4 may be turned on based on the light emission control signal G_EM having the logic high level. Also, in the sensing mode, the light emission control switch SW4 may maintain a turned-off state based on the light emission control signal G_EM having the logic low level.

The storage capacitor CST may be connected between the first node N1 and the third node N3 to store the gate-source voltage of the driving transistor TD.

As described above, the furnace circuit 10 according to the embodiments of the present invention is based on the first sensing control signal G_SEN and the emission control signal G_EM corresponding to the scan signal SCAN[k] and the global gate signal. The image display and sensing operations may be performed, and sequential light emission and simultaneous light emission operations may be selectively driven.

FIG. 3 is a timing diagram illustrating an example of an operation of the organic light emitting diode display of FIG. 1 .

1 to 3 , the organic light emitting display device 100 may operate in a sequential emission mode (PE), a simultaneous emission mode (CE), and a sensing mode (SENSING).

In one embodiment, the second sensing control signal provided to the gate electrode of the second sensing switch SW3 may correspond to a scan signal. Each of the first sensing control signal G_SEN and the emission control signal G_EM may correspond to a global gate signal commonly provided to the entire display panel 110 .

In the sequential emission mode PE, the first sensing control signal G_SEN may have a logic low level and the emission control signal G_EM may have a logic high level. Accordingly, in the sequential light emitting mode PE, the first sensing switch SW1 may maintain a turned-off state and the emission control switch SW4 may maintain a turned-on state. The scan signals having the logic high level are sequentially applied, and each of the pixel circuits may sequentially emit light. When the scan switch SW1 is turned on by the logic high level scan signal, the storage capacitor CST is charged with the data voltage VDATA[j] (in this case, the second power source ELVSS is connected to the ground voltage). equivalent) can be. When the scan signal changes to the logic low level, the scan switch SW1 is turned off, and a driving current is generated based on the gate-source voltage of the driving transistor TD corresponding to the data voltage VDATA[j]. The organic light emitting element EL may emit light.

The simultaneous emission mode CE may include a writing period and a simultaneous emission period. In the writing period and the simultaneous light emission period, the first sensing control signal G_SEN has the logic low level, and the first sensing switch SW1 can maintain a turned-off state. The emission control signal G_EM may have the logic low level in the writing period and the logic high level in the simultaneous emission period. Accordingly, the emission control switch SW4 may be turned off in the writing period and turned on in the simultaneous emission period.

Since the light emission control switch SW4 is turned off during the writing period, each of all pixel elements 10 maintains a state in which the data voltage is charged, and the light emission control switch SW4 is turned on during the simultaneous light emission period. The pixel circuits 10 may simultaneously emit light.

In the sensing mode SENSING, the first sensing control signal G_SEN may have the logic high level and the emission control signal G_EM may have the logic low level. Accordingly, the first sensing switch SW1 may maintain a turned-on state, and the light emission control switch SW4 may maintain a turned-off state. Accordingly, the second electrode of the diode-connected driving transistor TD may be connected to the second power source ELVSS that is a DC bias power source.

In the sensing mode (SENSING), the scan signals having the logic high level may be sequentially applied to the display panel 110 . Accordingly, the scan switch SW1 and the second sensing switch SW3 may be simultaneously controlled. When the scan signal is provided to the second sensing switch SW3 , the OLED display 100 may detect deterioration of the driving transistor TD. When the scan signal having the logic high level is applied to the pixel circuit 10, the gate-source voltage of the driving transistor TD is charged with the data voltage VDATA[j], and the driving current of the driving transistor TD is charged. (ie, the sensing current) flows to the second power source ELVSS through the data line DLj. In one embodiment, the sensing current may be detected and analyzed by the sensing block (or the controller 150) of FIG. 1 .

As described above, in the pixel circuit 10 and the organic light emitting display device 100 including the same, the first sensing switch SW2 and the light emitting control switch SW4 are connected to global gate signals (ie, the first sensing control signal ( G_SEN) and emission control signal G_EM), it is possible to easily detect and compensate for deterioration of the driving transistor TD of each pixel circuit 10 . In addition, since the global gate signals are output from a simple circuit configuration, the area and circuit complexity of the scan driver 1201 and the global gate driver 130 may be reduced. Thus, yield and reliability of the organic light emitting display device 100 may be increased.

FIG. 4 is a block diagram illustrating an example of the organic light emitting display device of FIG. 1 .

In FIG. 4 , overlapping descriptions of components described with reference to FIG. 1 will be omitted. In addition, the organic light emitting display device of FIG. 4 is substantially the same as or substantially the same as the organic light emitting display device 100 of FIG. 1 except for signals output by the global gate driver 131 and some sensing operations of the pixel circuit 11 may have a similar configuration.

Referring to FIG. 4 , the organic light emitting diode display 101 includes a display panel 111, a scan driver 121, a global gate driver 131, a data driver 141, a controller 151, and a power supply 161. can do.

The organic light emitting display device 100 may operate in an image display mode for displaying an image and a sensing mode. In one embodiment, the image display mode may operate as a simultaneous light emission mode. In one embodiment, the sensing mode may include a first sensing mode for detecting deterioration of the driving transistor and a second sensing mode for detecting deterioration of the organic light emitting diode.

The display panel 111 includes a plurality of scan lines SL1 to SLn, a plurality of first sensing control lines GL11 to GL1n, a plurality of emission control lines GL21 to GL2n, and a plurality of second sensing control lines. GL31 to GL3n, a plurality of data lines DL1 to DLm and a plurality of scan lines SL1 to SLn, a plurality of first sensing control lines GL11 to GL1n, and a plurality of emission control lines ( GL21 to GL2n), a plurality of second sensing control lines GL31 to GL3n, and a plurality of pixel circuits 11 respectively connected to a plurality of data lines DL1 to DLm (however, n and m is an integer greater than or equal to 2).

The scan driver 121 may sequentially provide the scan signal to the scan lines SL1 to SLn based on the scan control signal CON1. Accordingly, data voltages may be sequentially written to pixel rows corresponding to the scan lines SL1 to SLn, or pixel deterioration sensing may be sequentially performed.

The global gate driver 131 provides a first sensing control signal to the first sensing control lines GL11 to GL1n based on the gate control signal CON2 and generates a light emission control signal to the light emission control lines FL21 to GL2n. , and a second sensing control signal may be provided to the second sensing control lines GL31 to GL3n. Each of the first sensing control signal, the second sensing control signal, and the emission control signal may correspond to a global gate signal. That is, the first sensing control signal may be commonly provided to all pixel circuits 11 included in the display panel 111, and the second sensing control signal may be provided to all pixel circuits included in the display panel 111. (11), and the emission control signal can also be commonly provided to all pixel circuits 11 included in the display panel 111. According to the logic levels of the first sensing control signal and the second sensing control signal, the organic light emitting display device 101 may detect deterioration of the driving transistor or the organic light emitting diode. In one embodiment, the global gate driver 131 may be physically included in the scan driver 121 .

The data driver 141 may generate data voltages based on the data driving control signal CON3 including image data. The data voltage may be provided to data lines DL1 to DLm.

The controller 151 may compensate for the data voltage or the image data by analyzing the sensing current flowing in each of the pixel circuits 11 through the respective data lines DL1 to DLm. Accordingly, deterioration of the driving transistor and/or deterioration of the organic light emitting diode may be compensated for.

The power supply unit 160 may provide the first power source ELVDD and the second power source ELVSS having a lower voltage level than the first power source ELVDD to the display panel 110 . In one embodiment, the second power source ELVSS may correspond to the ground voltage.

As described above, the organic light emitting diode display 101 according to embodiments of the present invention includes a separate sensing line for detecting deterioration of the pixel circuit 11 (or compensating for external deterioration) and the sensing line and the data line, respectively. A buffer driver for discriminating between provided signals may be removed. In addition, since all signals controlling image display and sensing operations correspond to the global gate signal, the area and circuit complexity of the scan driver 120 and the global gate driver 130 may be reduced. Thus, yield and reliability of the organic light emitting display device 100 may be increased.

FIG. 5 is a circuit diagram illustrating an example of a pixel circuit included in the organic light emitting diode display of FIG. 4 .

In FIG. 5 , overlapping descriptions of components described with reference to FIG. 2 will be omitted. In addition, the pixel circuit of FIG. 5 may have a configuration substantially the same as or similar to the pixel circuit 100 of FIG. 2 except for the second sensing control signal applied to the second sensing switch SW3 .

Referring to FIG. 5 , the pixel circuit 11 includes an organic light emitting diode (EL), a scan switch (SW1), a driving transistor (TD), a first sensing switch (SW2), a second sensing switch (SW3), and an emission control switch. (SW4) and a storage capacitor (CST).

The pixel circuit 11 may be driven in an image display mode and a sensing mode. The image display mode may be implemented as a simultaneous emission mode by the first sensing control signal G_SEN1, the second sensing control signal G_SEN2, and the emission control signal G_EM included in the global gate signals. The sensing mode may include a first sensing mode for detecting deterioration characteristics of the driving transistor TD and a second sensing mode for detecting deterioration characteristics of the organic light emitting diode EL. That is, the current flowing through the driving transistor TD may be detected in the first sensing mode, and the current flowing through the organic light emitting diode EL may be detected in the second sensing mode.

Since the configuration of the pixel circuit 11 is substantially the same as that of the pixel circuit 10 of FIG. 2 , overlapping descriptions will be omitted.

The second sensing control signal G_SEN2, which is a global gate signal, may be applied to the gate electrode of the second sensing switch SW2. The second sensing control signal G_SEN2 is

In one embodiment, in the first sensing mode, both the first sensing switch SW2 and the second sensing switch SW3 may maintain a turned-on state, and the light emission control switch SW4 may maintain a turned-off state. Accordingly, the second electrode (ie, the source electrode) of the driving transistor TD is connected to the second power source ELVSS, and the sensing current flowing through the driving transistor TD is detected through the data line DLj, thereby driving A characteristic (deterioration) of the transistor TD can be detected.

In one embodiment, in the second sensing mode, the first sensing switch SW2 may remain turned on, and the second sensing switch SW3 and light emission control switch SW4 may remain turned off. Accordingly, since the sensing current flowing through the organic light emitting diode EL is detected through the data line DLj, the characteristic (deterioration) of the organic light emitting diode EL may be detected.

As such, the second sensing control signal G_SEN2, which is a global gate signal, is provided to the second sensing switch SW3 connected in parallel with the organic light emitting diode EL, thereby providing the simple structure of the pixel circuit 11 and the structure of the simple structure. A characteristic change (deterioration, etc.) of not only the driving transistor TD but also the organic light emitting diode EL can be easily detected from the scan driver (and the global gate driver).

6 is a timing diagram for explaining an example of an operation of the organic light emitting diode display of FIG. 4 .

Referring to FIGS. 4 to 6 , the organic light emitting display device 101 may operate in a simultaneous emission mode (CE) and a first sensing mode (SENSING1).

In one embodiment, the second sensing control signal G_SEN2 provided to the gate electrode of the second sensing switch SW3 may correspond to a global gate signal. The simultaneous emission mode CE may include a writing period and a simultaneous emission period. The simultaneous emission mode CE in FIG. 6 may operate substantially the same as the simultaneous emission mode CE described with reference to FIG. 3 .

During the writing period and the simultaneous light emission period, the first sensing control signal G_SEN1 may have the logic low level, and the first sensing switch SW1 may maintain a turned-off state. The emission control signal G_EM may have the logic low level in the writing period and the logic high level in the simultaneous emission period. Accordingly, the emission control switch SW4 may be turned off in the writing period and turned on in the simultaneous emission period. The second sensing control signal G_SEN2 may have the logic high level in the writing period and the logic low level in the simultaneous emission period. Accordingly, the second sensing switch SW3 may be turned on in the writing period and turned off in the simultaneous emission period. Accordingly, all of the pixel circuits 11 may simultaneously emit light in the emission period.

In the first sensing mode SENSING1, the first sensing control signal G_SEN1 and the second sensing control signal G_SEN2 may have the logic high level, and the emission control signal G_EM may have the logic low level. Accordingly, in the first sensing mode SENSING1 , the first sensing switch SW1 and the second sensing switch SW2 may maintain a turned-on state, and the light emission control switch SW4 may maintain a turned-off state. When the scan signal having the logic high level is applied to the pixel circuit 11, the gate-source voltage of the driving transistor TD is charged with the data voltage VDATA[j], and the driving current of the driving transistor TD is charged. (ie, the sensing current) flows to the second power source ELVSS through the data line DLj. A deterioration detection operation may be sequentially performed on pixel rows corresponding to each scan line. In one embodiment, the sensing current may be detected and analyzed by the sensing block (or controller 151) of FIG. 4 .

FIG. 7 is a timing diagram for explaining another example of an operation of the organic light emitting diode display of FIG. 4 .

In FIG. 7 , a description overlapping with the operation described with reference to FIG. 6 will be omitted.

Referring to FIGS. 4, 5, and 7 , the organic light emitting display device 101 may operate in a simultaneous emission mode (CE) and a second sensing mode (SENSING2).

In the second sensing mode SENSING2, the first sensing control signal G_SEN1 may have a logic high level, and the second sensing control signal G_SEN2 and the emission control signal G_EM may have a logic low level. Accordingly, in the second sensing mode SENSING2 , the first sensing switch SW2 may remain turned on, and the second sensing switch SW3 and the light emission control switch SW4 may maintain a turned off state. When the scan signal having the logic high level is applied to the pixel circuit 11, the gate-source voltage of the driving transistor TD is charged with the data voltage VDATA[j] and flows through the organic light emitting diode EL. Current (ie, sensing current) flows to the second power source ELVSS through the data line DLj. A deterioration detection operation may be sequentially performed on pixel rows corresponding to each scan line. In one embodiment, the sensing current may be detected and analyzed by the sensing block (or controller 151) of FIG. 4 .

As described above, the pixel circuit 11 and the organic light emitting display device 101 including the pixel circuit 11 according to embodiments of the present invention include a first sensing switch SW2, a second sensing switch SW3, and a light emitting control switch ( SW4), and the first sensing switch SW2, the second sensing switch SW3, and the light emission control switch SW4 are connected to global gate signals (ie, the first sensing control signal G_SEN1, the second sensing control signal (G_SEN2) and the emission control signal (G_EM)), deterioration of the driving transistor TD and organic light emitting diode EL of each pixel circuit 11 can be easily detected.

In addition, since the first sensing switch SW2, the second sensing switch SW3, and the emission control switch SW4 are controlled from the global gate signals that can be output from a simple circuit configuration, a separate sensing line for pixel sensing is eliminated. In addition, the area and circuit complexity of the scan driver 121 and the global gate driver 131 may be reduced. Thus, yield and reliability of the organic light emitting display device 100 may be increased.

FIG. 8 is a diagram for explaining another example of an operation of the organic light emitting diode display of FIG. 4 .

Referring to FIG. 8 , the pixel circuit 11 and the organic light emitting display device 101 including the pixel circuit 11 may operate in an image display mode (ie, simultaneous emission mode) and a sensing mode. The image display mode includes an image display period DIS in which the pixel circuit 11 and the organic light emitting display device 101 display an image. The sensing mode includes a first sensing period SEN1 and a second sensing period SEN2 for detecting the sensing current flowing in the pixel circuit 11 .

The image display period DIS may include a plurality of consecutive frames nFRAMES.

The first sensing period SEN1 and the second sensing period SEN2 may be respectively disposed between the image display periods DIS. In one embodiment, the first sensing period SEN1 may be set as a preset frame period. Similarly, the second sensing period SEN2 may be set as a preset frame period.

The first sensing period SEN1 is a period in which the first sensing current flowing through the driving transistor TD is detected. Accordingly, threshold voltage characteristics and mobility characteristics of the driving transistor TD may be detected in the first sensing period SEN1 . In one embodiment, the first sensing period SEN1 may be set periodically. For example, as shown in FIG. 8 , the first sensing period SEN1 may be arranged at 2n frame intervals, and the first sensing current may be detected at 2n frame intervals. However, this is an example, and the period of the first sensing period SEN1 is not limited thereto, and the first sensing period SEN1 may be set non-periodically.

The second sensing period SEN2 is a period in which the second sensing current flowing through the organic light emitting diode EL is detected. Therefore, deterioration of the organic light emitting diode EL may be detected in the second sensing period SEN2 . In one embodiment, the second sensing period SEN2 may be set periodically. For example, as shown in FIG. 8 , the second sensing period SEN2 may be arranged at 2n frame intervals, and the second sensing current may be detected in real time at 2n frame intervals. However, this is an example, and the period of the second sensing period SEN2 is not limited thereto, and the second sensing period SEN2 may be set non-periodically.

Also, the period of the first sensing period SEN1 and the period of the second sensing period SEN2 may be different from each other. The first sensing period SEN1 and the second sensing period SEN2 may be set by a user command.

9 is a block diagram illustrating an electronic device according to embodiments of the present invention, FIG. 10A is a diagram illustrating an example in which the electronic device of FIG. 9 is implemented as a television, and FIG. 10B is a diagram showing the electronic device of FIG. 9 as a smartphone. It is a drawing showing an example implemented as

9 to 10B , the electronic device 1000 includes a processor 1010, a memory device 1020, a storage device 1030, an input/output device 1040, a power supply 1050, and an organic light emitting display device 1060. ) may be included. In this case, the organic light emitting display device 1060 may correspond to the organic light emitting display devices 100 and 101 of FIG. 1 or FIG. 4 . The electronic device 1000 may further include several ports capable of communicating with a video card, a sound card, a memory card, a USB device, or the like, or with other systems. In one embodiment, as shown in FIG. 10A , the electronic device 1000 may be implemented as a television. In another embodiment, as shown in FIG. 10B , the electronic device 1000 may be implemented as a smart phone. However, this is an example and the electronic device 1000 is not limited thereto. For example, the electronic device 1000 includes a mobile phone, a video phone, a smart pad, a smart watch, a tablet PC, a vehicle navigation system, a computer monitor, a laptop computer, and a head mounted display. ; HMD) and the like.

Processor 1010 may perform certain calculations or tasks. Depending on the embodiment, the processor 1010 may be a microprocessor, a central processing unit, an application processor, or the like. The processor 1010 may be connected to other components through an address bus, a control bus, and a data bus. According to an embodiment, the processor 1010 may also be connected to an expansion bus such as a Peripheral Component Interconnect (PCI) bus. The memory device 1020 may store data necessary for the operation of the electronic device 1000 . For example, the memory device 1020 may include an Erasable Programmable Read-Only Memory (EPROM) device, an Electrically Erasable Programmable Read-Only Memory (EEPROM) device, a flash memory device, a PRAM ( Phase Change Random Access Memory (PRAM) device, Resistance Random Access Memory (RRAM) device, Nano Floating Gate Memory (NFGM) device, Polymer Random Access Memory (PoRAM) device, MRAM (Magnetic Random Access Memory; MRAM), non-volatile memory devices such as FRAM (Ferroelectric Random Access Memory; FRAM) devices and/or DRAM (Dynamic Random Access Memory; DRAM) devices, SRAM (Static Random Access Memory; SRAM) devices, mobile A volatile memory device such as a DRAM device may be included. The storage device 1030 may include a solid state drive (SSD), a hard disk drive (HDD), a CD-ROM, and the like. The input/output device 1040 may include an input means such as a keyboard, a keypad, a touch pad, a touch screen, and a mouse, and an output means such as a speaker and a printer. The power supply 1050 may supply power necessary for the operation of the electronic device 1000 .

The OLED display 1060 may be connected to other components through the buses or other communication links. According to exemplary embodiments, the organic light emitting display device 1060 may be included in the input/output device 1040 . As described above, the organic light emitting display device 1060 may operate in an image display mode and a sensing mode. To this end, the organic light emitting display device 1060 includes a display panel including a plurality of pixel circuits, a data driver providing data voltages to the display panel, a scan driver providing scan signals to the display panel, and a plurality of global gates in the display panel. A global gate driver that provides signals (eg, a sensing control signal and a light emitting control signal), a controller that analyzes the sensing current output from the pixel circuits and compensates for the data voltage, and a first power voltage and A power supply unit supplying a second power voltage may be included.

The present invention can be applied to a display device that performs a pixel current sensing operation and an electronic device having the same. For example, the present invention can be applied to televisions, personal computers, notebooks, tablets, mobile phones, smart phones, smart pads, PDAs, PMPs, digital cameras, MP3 players, portable game consoles, navigation, and the like.

Although the above has been described with reference to the embodiments of the present invention, those skilled in the art can variously modify and change the present invention without departing from the spirit and scope of the present invention described in the claims below. You will understand that you can.

10, 11: pixel circuit 100, 101: organic light emitting display device
110, 111: display panel 120, 121: scan driving unit
130, 131: global gate driver 140, 141: data driver
150, 151: control unit 160, 161: power unit

Claims (20)

an organic light emitting diode having a cathode connected to a second power source;
a scan switch having a gate electrode to which a scan signal is applied, a first electrode to which a data voltage is applied, and a second electrode connected to the first node;
a driving transistor including a gate electrode connected to the first node, a first electrode connected to a second node, and a second electrode connected to a third node corresponding to the anode of the organic light emitting diode;
a first sensing switch having a gate electrode to which a first sensing control signal is applied, a first electrode connected to the first node, and a second electrode connected to the second node;
a second sensing switch having a gate electrode to which a second sensing control signal is applied, a first electrode connected to the third node, and a second electrode connected to the second power source;
a light emission control switch having a gate electrode to which a light emission control signal is applied, a first electrode connected to a first power source, and a second electrode connected to the second node; and
A storage capacitor connected between the first node and the third node;
A pixel circuit driven in an image display mode and a sensing mode. The pixel circuit of claim 1 , wherein each of the first sensing control signal and the emission control signal corresponds to a global gate signal. The method of claim 2, wherein the second sensing control signal corresponds to the scan signal, and the scan switch and the second sensing switch are simultaneously controlled,
When the second sensing control signal corresponds to the scan signal, the image display mode operates in a simultaneous light emitting mode or a sequential light emitting mode. 4 . The pixel circuit of claim 3 , wherein in the sensing mode, the first sensing switch maintains a turned-on state and the emission control switch maintains a turned-off state. 5. The pixel circuit of claim 4, wherein in the sensing mode, the first sensing control signal has a logic high level and the emission control signal has a logic low level. 5 . The pixel circuit of claim 4 , wherein in the sensing mode, a sensing current flowing through a data line is detected based on a gate-source voltage of the driving transistor when the scan switch and the second sensing switch are turned on. . 4 . The pixel circuit of claim 3 , wherein in the sequential light emission mode, the first sensing switch maintains a turned-off state and the emission control switch maintains a turned-on state. 4. The method of claim 3, wherein the simultaneous emission mode includes a writing period and a simultaneous emission period,
the light emission control switch is turned off in the writing period and turned on in the simultaneous light emission period;
The pixel circuit, characterized in that the first sensing switch maintains a turn-off state in the simultaneous light emission mode. The method of claim 1 , wherein each of the first sensing control signal, the second sensing control signal, and the emission control signal corresponds to a global gate signal,
The sensing mode is divided into a first sensing mode for detecting a deterioration characteristic of the driving transistor and a second sensing mode for detecting a deterioration characteristic of the organic light emitting diode.
The pixel circuit according to claim 1 , wherein the image display mode corresponds to a simultaneous light emission mode. 10 . The pixel circuit of claim 9 , wherein in the first sensing mode, the first sensing switch and the second sensing switch maintain a turned-on state, and the emission control switch maintains a turned-off state. 11. The pixel circuit of claim 10, wherein in the first sensing mode, the first and second sensing control signals have a logic high level and the emission control signal has a logic low level. . 10. The pixel circuit of claim 9, wherein in the second sensing mode, the first sensing switch maintains a turned-on state, and the second sensing switch and the emission control switch maintain a turned-off state. 13. The method of claim 12 , wherein in the second sensing mode, the first sensing control signal has a logic high level, and the second sensing control signal and the emission control signal have a logic low level. A pixel circuit made of . 13 . The pixel circuit of claim 12 , wherein in the second sensing mode, when the scan switch is turned on, a sensing current flowing through the organic light emitting diode is detected through a data line. a display panel including a plurality of pixel circuits driven in an image display mode or sensing mode and connected to a scan line, a data line, a first sensing control line, a second sensing control line, and an emission control line;
a scan driver providing a scan signal to the scan line;
a global gate driver configured to provide a first sensing control signal to the first sensing control line and a light emission control signal to the light emission control line;
a data driver providing a data voltage to the data line based on image data;
a control unit that analyzes a sensing current flowing through each of the pixel circuits through the data line and compensates for the data voltage or the image data; and
a power supply unit configured to provide a first power source and a second power source having a lower voltage level than the first power source to the display panel;
Each of the plurality of pixel circuits,
an organic light emitting diode having a cathode connected to the second power source;
a scan switch having a gate electrode to which the scan signal is applied, a first electrode to which the data voltage is applied, and a second electrode connected to a first node;
a driving transistor including a gate electrode connected to the first node, a first electrode connected to a second node, and a second electrode connected to a third node corresponding to the anode of the organic light emitting diode;
a first sensing switch having a gate electrode connected to the first sensing control line to receive the first sensing control signal, a first electrode connected to the first node, and a second electrode connected to the second node;
a second sensing switch having a gate electrode connected to the second sensing control line to receive the second sensing control signal, a first electrode connected to the third node, and a second electrode connected to the second power source;
a light emitting control switch having a gate electrode connected to the light emitting control line to receive the light emitting control signal, a first electrode connected to a first power supply, and a second electrode connected to the second node; and
and a storage capacitor connected between the first node and the third node. 16. The method of claim 15, wherein the first sensing control signal and the emission control signal correspond to a global gate signal, respectively, and the second sensing control signal corresponds to the scan signal,
The organic light emitting display device according to claim 1 , wherein the image display mode operates in a simultaneous light emitting mode or a sequential light emitting mode. 17. The method of claim 16, wherein in the sensing mode, the first sensing switch maintains a turn-on state, the emission control switch maintains a turn-off state, and the control unit degrades the driving transistor based on the sensing current. An organic light emitting display device characterized in that for analyzing. 16. The method of claim 15, wherein the global gate driver provides the second sensing control signal to the second sensing control line,
The first sensing control signal, the second sensing control signal, and the emission control signal each correspond to a global gate signal;
The sensing mode includes a first sensing mode for detecting a deterioration characteristic of the driving transistor and a second sensing mode for detecting a deterioration characteristic of the organic light emitting diode;
The organic light emitting display device according to claim 1 , wherein the image display mode operates in a simultaneous emission mode. 19. The organic light emitting diode display of claim 18, wherein in the first sensing mode, the first sensing switch and the second sensing switch maintain a turned-on state, and the emission control switch maintains a turned-off state. . 19. The method of claim 18, wherein in the second sensing mode, the first sensing switch maintains a turn-on state, the second sensing switch and the light emission control switch maintain a turn-off state, and when the scan switch is turned on The organic light emitting display device characterized in that the sensing current flowing through the organic light emitting diode is detected.

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