KR20170123388A - Pixel circuit and organic light emitting display device having the same - Google Patents

Abstract

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

Description

TECHNICAL FIELD [0001] The present invention relates to a pixel circuit, and an OLED display including the OLED display device.

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 including the pixel circuit.

An organic light emitting display is an apparatus that displays an image using an organic light emitting diode. In the OLED display device, a characteristic difference such as a threshold voltage and a mobility of a driving transistor is generated for each pixel due to a process variation or the like, and a luminance variation and an afterimage are generated between pixels in accordance with deterioration of the organic light emitting diode .

A conventional organic light emitting display device applies a reference voltage to the pixel circuits through a sensing line (or a reference line) arranged in units of a plurality of pixel circuits, and based on the individual gate signals applied corresponding to the pixel rows Measure the sensing current. Therefore, a buffer driver for the sensing line and the like are required in the sensing line and the data driver, and a driver circuit for generating the gate signals is required. Therefore, the area and complexity of the system and the driver are greatly increased. Also, the voltage and current of each of the pixel circuits or each of the organic light emitting diodes can not be measured, so that deterioration of the organic light emitting diode can not be detected.

It is an object of the present invention to provide a pixel circuit in which a sensing current for detecting deterioration of a driving transistor and / or an organic light emitting diode is output 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.

It should be understood, however, that the present invention is not limited to the above-described embodiments, and various changes and modifications may be made without departing from the spirit and scope of the invention.

In order to accomplish one object of the present invention, a pixel circuit according to embodiments of the present invention includes an organic light emitting diode in which a cathode is connected to a second power source, a gate electrode to which a scan signal is applied, A scan electrode connected to the first node, a scan electrode connected to the first node, a gate electrode connected to the first node, a first electrode coupled to the second node, and a third electrode coupled to the third node corresponding to the anode of the organic light emitting diode. A first sensing switch including 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 coupled to the third node, and a second electrode coupled to the second power source, An emission control switch having an applied gate electrode, a first electrode coupled to a first power supply and a second electrode coupled to the second node, and a storage capacitor coupled between the first node and the third node, , A video display mode and a sensing mode.

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

According to an embodiment, the second sensing control signal corresponds to the scan signal, and the scan switch and the second sensing switch can be simultaneously controlled. When the second sensing control signal corresponds to the scan signal, the image display mode may be 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, and the light emission control switch maintains a turn-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 one embodiment, in the sensing mode, when the scan switch and the second sensing switch are turned on, a sensing current flowing in the data line based on the gate-source voltage of the driving transistor may be detected.

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

According to one embodiment, the simultaneous light emission mode may include a write period and a simultaneous light emission period. The light emission control switch may be turned off in the write period, turned on in the simultaneous light emission period, and the first sensing switch may be maintained in the turn off state in the simultaneous light emission mode.

According to an embodiment, each of the first sensing control signal, the second sensing control signal, and the light 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 light emission mode.

According to an embodiment, in the first sensing mode, the first sensing switch and the second sensing switch maintain the turn-on state, and the light emission control switch can maintain the turn-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 maintains the turn-on state, and the second sensing switch and the emission control switch maintain the turn-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 light 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 in the organic light emitting diode may be detected through a data line.

In order to accomplish one object of the present invention, an OLED display 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, A scan driver for providing a scan signal to the scan line, a first sensing control signal to the first sensing control line, and a second sensing control signal to the emission control line, A data driver for providing a data voltage to the data lines based on the image data, a controller for analyzing a sensing current flowing through each of the pixel circuits through the data lines, And a second power source having a voltage level lower than that of the first power source A second power supply may include a power source for providing 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 source, a gate electrode to which the scan signal is applied, a first electrode to which the data voltage is applied, A gate electrode connected to the first node, a first electrode coupled to the second node, and a second electrode coupled to a third node corresponding to the anode of the organic light emitting diode, A first sensing switch coupled to the first sensing control line and having a gate electrode receiving the first sensing control signal, a first electrode coupled to the first node, and a second electrode coupled to the second node, A gate electrode coupled to the second sensing control line to receive the second sensing control signal, a first electrode coupled to the third node, A second sensing switch connected to the emission control line, a gate electrode connected to the emission control signal, a first electrode connected to the 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.

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

According to an embodiment, in the sensing mode, the first sensing switch maintains the turn-on state, the emission control switch maintains the turn-off state, and the control unit controls the deterioration Can be analyzed.

According to an embodiment, the global gate driver may provide the second sensing signal to the second sensing control line. The first sensing control signal, the second sensing control signal, and the emission control signal may correspond to a global gate signal, respectively. 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 deterioration characteristics of the organic light emitting diode, and the image display mode may operate in a simultaneous light emission mode.

According to an embodiment, in the first sensing mode, the first sensing switch and the second sensing switch maintain the turn-on state, and the light emission control switch can maintain the turn-off state.

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

The pixel circuit according to the embodiments of the present invention and the organic light emitting display including the same may be omitted from the configuration of a sensing line and a gate driver for detecting deterioration of the pixel circuit (or external deterioration compensation). In addition, signals for controlling image display and sensing operations are all connected to global gate signals (e.g., at least one of a first sensing control signal, a second sensing control signal, and a light emission control signal) The area and circuit complexity of the scan driver and the global gate driver can be reduced. Therefore, the yield and reliability of the organic light emitting display device can be increased.

Further, 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 effects described above, and may be variously extended without departing from the spirit and scope of the present invention.

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

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

1 is a block diagram illustrating an organic light emitting display according to embodiments of the present invention.

1, the OLED 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 source 160 can do.

The OLED display 100 may operate in an image display mode and a sensing mode for displaying an image. In one embodiment, the image display mode may operate in a sequential light emitting mode or a simultaneous light emitting 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, a plurality of data lines DL1 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 (Where n and m are integers equal to or larger than 2).

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

The scan driver 120 may sequentially provide the scan signals to the scan lines SL1 to SLn based on the scan control signal CON1. Accordingly, the data voltages may be sequentially written to the pixel rows corresponding to the scan lines SL1 to SLn, or the 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 supplied to the gate electrode of the scan transistor and the gate electrode of the second sensing switch. However, in an alternative 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 supplies the first sensing control signal to the light emission control lines FL21 to GL2n, A control signal can be provided. The first sensing control signal and the emission control signal may correspond to a global gate signal, respectively. That is, the first sensing control signal may be commonly provided to all the pixel circuits 10 included in the display panel 110, and the emission control signal may also be provided to all the pixel circuits 10 ). ≪ / RTI > The pixel circuits 10 may sequentially emit light or simultaneously emit light according to the logic levels of the first sensing control signal and the light emission control signal. In one embodiment, the global gate driver 130 may physically be included in the scan driver 120.

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

The controller 150 may compensate the data voltage or the image data by analyzing the sensing currents flowing through the pixel circuits 10 through the respective data lines DL1 to DLm. Accordingly, deterioration of the driving transistor and / or deterioration of the organic light emitting diode can be compensated. The compensated image data or the compensated data voltage may be provided to the data driver 140. In one embodiment, the controller 150 may physically be 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 display panel 110 with a first power ELVDD and a second power ELVSS having a voltage level lower than that of the first power ELVDD. In one embodiment, the second power supply ELVSS may correspond to a ground voltage.

As described above, the OLED display 100 according to the embodiments of the present invention is configured such that the configuration of a separate sensing line and gate driver for detecting deterioration (or external deterioration compensation) of the pixel circuit 10 is removed .

In addition, since the signals for controlling the image display and sensing operations correspond to the 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. Therefore, the yield and reliability of the OLED display 100 can be increased.

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

2, the pixel circuit 10 includes an organic light emitting diode (EL), a scan switch SW1, a drive transistor TD, a first sensing switch SW2, a second sensing switch SW3, A 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 emission control switch SW4 are formed of an N-channel metal oxide semiconductor (NMOS) NMOS) transistors. The NMOS transistors may be formed of an oxide thin film transistor (TFT), an amorphous silicon (a-Si TFT) transistor, or a poly-silicon (Poly-Si TFT) transistor. However, this is merely an example, and the scan switch SW1, the driving transistor TD, the first sensing switch SW2, the second sensing switch SW3, and the emission control switch SW4 may be formed of P-channel Metal Oxide Semiconductor (PMOS) transistors.

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

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

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

The driving transistor TD has a gate electrode connected to the first node N1, a first electrode connected to the second node N2 and a third electrode connected to the 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 be a storage capacitor It is possible to generate a drive current corresponding to the voltage charged in the capacitor CST.

The first sensing switch SW2 includes a gate electrode to which a 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 . In one embodiment, the first sensing control signal G_SEN may be a global gate signal commonly applied across the display panel. In the image display mode, the first sensing switch SW2 can maintain the turn-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 can maintain the turn-on state based on the first sensing control signal G_SEN having the logic high level. Accordingly, the driving transistor (TD) diode may be connected in the sensing mode.

The second sensing switch SW3 may include a gate electrode to which a second sensing control signal is applied, a first electrode coupled to the third node N3, and a second electrode coupled to the second power source ELVSS. In this embodiment, the second sensing control signal may correspond to the scan signal SCAN [k]. Therefore, the scan switch SW1 and the second sensing switch SW3 can 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. The second sensing switch SW3 is turned on in the sensing mode for sensing the deterioration of the driving transistor TD so that the second electrode of the driving transistor TD is electrically connected to the second power ELVSS Ground voltage). Therefore, the degree of deterioration of the driving transistor (for example, threshold voltage change, mobility change, etc.) in the sensing mode can be detected.

The emission control switch SW4 may include a gate electrode to which the emission control signal G_EM is applied, a first electrode coupled to the first power source ELVDD, and a second electrode coupled to the second node N2. In one embodiment, the emission control signal G_EM may be a global gate signal commonly applied across the display panel. In the video display mode, the emission control switch SW4 can be turned on based on the emission control signal G_EM having the logic high level. Further, in the sensing mode, the emission control switch SW4 can maintain the turn-off state based on the 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 flashing circuit 10 according to the embodiments of the present invention is capable of generating the first sensing control signal G_SEN and the light emission control signal G_EM corresponding to the scan signal SCAN [k], the global gate signal, The image display and sensing operations may be performed, and the sequential light emission and simultaneous light emission operations may be selectively performed.

3 is a timing chart for explaining an example of the operation of the organic light emitting diode display of FIG.

1 to 3, the OLED display 100 may operate in a sequential light emission mode (PE), a simultaneous light 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. 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 light 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 emission mode PE, the first sensing switch SW1 maintains the turn-off state and the light emission control switch SW4 can maintain the turn-on state. The scan signals having the logic high level are sequentially applied, and each of the pixel circuits can sequentially emit light. When the scan switch SW1 is turned on by the logic high level scan signal, the data voltage VDATA [j] is charged to the storage capacitor CST (in this case, the second power ELVSS is set to the ground voltage ). ≪ / RTI > When the scan signal changes to the logic low level, the scan switch SW1 is turned off, and a drive current is generated based on the gate-source voltage of the drive transistor TD corresponding to the data voltage VDATA [j] The organic light emitting element EL can emit light.

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

Since the light emission control switch SW4 is turned off in the write period, each of the pixel sites 10 maintains the data voltage charged state, and the light emission control switch SW4 is turned on during the simultaneous light emission period, The pixel circuits 10 can 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 maintains the turn-on state and the light emission control switch SW4 can maintain the turn-off state. Therefore, the second electrode of the driving transistor TD having a diode-connected configuration can be connected to the second power source ELVSS, which is a DC bias power source.

The scan signals having the logic high level may be sequentially applied to the display panel 110 in the sensing mode. Accordingly, the scan switch SW1 and the second sensing switch SW3 can be controlled simultaneously. When the scan signal is supplied to the second sensing switch SW3, the OLED display 100 can detect the 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 drive transistor TD is charged to the data voltage VDATA [j] (I.e., 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 controller 150) of FIG.

The pixel circuit 10 and the organic light emitting diode display 100 including the pixel circuit 10 are connected to the first sensing switch SW2 and the emission control switch SW4 as global gate signals G_SEN) and the emission control signal (G_EM)), deterioration of the driving transistor (TD) of the individual pixel circuit (10) can be easily detected and compensated. In addition, since the global gate signals are outputted from a simple circuit configuration, the area and circuit complexity of the scan driver 1201 and the global gate driver 130 can be reduced. Therefore, the yield and reliability of the OLED display 100 can be increased.

4 is a block diagram showing an example of the organic light emitting diode display of FIG.

In FIG. 4, a repeated description of the components described with reference to FIG. 1 will be omitted. 4 may be substantially the same as or similar to the organic light emitting display 100 of FIG. 1 except for the signals output from the global gate driver 131 and the sensing operation of the pixel circuit 11 It can have a similar configuration.

4, the OLED 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 driver 161 can do.

The OLED display 100 may operate in an image display mode and a sensing mode for displaying an image. In one embodiment, the image display mode may operate in 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, 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 GL1 to GLn, GL21 to GL2n, a plurality of second sensing control lines GL31 to GL3n and a plurality of data lines DL1 to DLm, m is an integer of 2 or more).

The scan driver 121 may sequentially provide the scan signals to the scan lines SL1 to SLn based on the scan control signal CON1. Accordingly, the data voltages may be sequentially written to the pixel rows corresponding to the scan lines SL1 to SLn, or the 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 outputs a first sensing control signal to the light emission control lines FL21 to GL2n, And may provide a second sensing control signal to the second sensing control lines GL31 to GL3n. The first sensing control signal, the second sensing control signal, and the emission control signal may correspond to a global gate signal, respectively. That is, the first sensing control signal may be commonly provided to all the pixel circuits 11 included in the display panel 111, and the second sensing control signal may be provided to all the pixel circuits 111 included in the display panel 111 And the light emission control signal may be provided commonly to all the pixel circuits 11 included in the display panel 111. In addition, The organic light emitting diode display 101 may detect deterioration of the driving transistor or the organic light emitting diode according to the logic levels of the first sensing control signal and the second sensing control signal. In one embodiment, the global gate driver 131 may be physically included in the scan driver 121. [

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

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

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

As described above, the OLED display 101 according to the embodiments of the present invention includes a separate sensing line for detecting deterioration (or external deterioration compensation) of the pixel circuit 11, and a sensing line The buffer driver for discriminating the provided signals can be eliminated. Since the signals for controlling the image display and sensing operations correspond to the global gate signals, the area and circuit complexity of the scan driver 120 and the global gate driver 130 can be reduced. Therefore, the yield and reliability of the OLED display 100 can be increased.

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

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

5, the pixel circuit 11 includes an organic light emitting diode EL, a scan switch SW1, a drive transistor TD, a first sensing switch SW2, a second sensing switch SW3, A switch SW4 and a storage capacitor CST.

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

The configuration of the pixel circuit 11 is substantially the same as the configuration of the pixel circuit 10 of FIG. 2, and thus a duplicated description will be omitted.

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

In one embodiment, in the first sensing mode, the first sensing switch SW2 and the second sensing switch SW3 are both turned on, and the light emission control switch SW4 is maintained in a turned off state. Accordingly, the second electrode (i.e., 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, The characteristic (deterioration) of the transistor TD can be detected.

In one embodiment, in the second sensing mode, the first sensing switch SW2 is maintained in a turned-on state, and the second sensing switch SW3 and the emission control switch SW4 are maintained in a turned-off state. Accordingly, the sensing current flowing through the organic light emitting diode EL is detected through the data line DLj, so that the characteristic (deterioration) of the organic light emitting diode EL can be detected.

Thus, 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. Thus, the pixel circuit 11 of simple structure and the simple structure (Deterioration or the like) of the organic light emitting diode EL as well as the driving transistor TD from the scan driver (and the global gate driver) can be easily detected.

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

Referring to FIGS. 4 to 6, the organic light emitting diode display 101 may operate in a simultaneous light 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 light emission mode CE may include a write period and a simultaneous light emission period. The simultaneous light emission mode CE in FIG. 6 can be operated substantially the same as the simultaneous light emission mode CE described with reference to FIG.

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

In the first sensing mode SENSING1, the first sensing control signal G_SEN1 and the second sensing control signal G_SEN2 have the logic high level and the emission control signal G_EM can have the logic low level. Accordingly, in the first sensing mode SENSING1, the first sensing switch SW1 and the second sensing switch SW2 are maintained in a turned-on state, and the emission control switch SW4 is maintained in 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 drive transistor TD is charged to the data voltage VDATA [j] (I.e., the sensing current) flows to the second power source ELVSS through the data line DLj. The deterioration detecting operation can be sequentially performed on the pixel rows corresponding to the respective scan lines. In one embodiment, the sensing current may be detected and analyzed by the sensing block (or controller 151) of FIG.

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

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

4, 5, and 7, the organic light emitting display device 101 may operate in a simultaneous light 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 is maintained in the turned-on state, and the second sensing switch SW3 and the emission control switch SW4 are maintained in the 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 to the data voltage VDATA [j] The current (i.e., sensing current) flows through the data line DLj to the second power source ELVSS. The deterioration detecting operation can be sequentially performed on the pixel rows corresponding to the respective scan lines. In one embodiment, the sensing current may be detected and analyzed by the sensing block (or controller 151) of FIG.

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

In addition, since the first sensing switch SW2, the second sensing switch SW3, and the light 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 And the area and circuit complexity of the scan driver 121 and the global gate driver 131 can be reduced. Therefore, the yield and reliability of the OLED display 100 can be increased.

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

Referring to FIG. 8, the pixel circuit 11 and the OLED display 101 including the pixel circuit 11 may operate in an image display mode (i.e., a simultaneous light 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 sensing a sensing current flowing through the pixel circuit 11. [

The video display section DIS may include a plurality of consecutive frames nFRAMES.

The first sensing period SEN1 and the second sensing period SEN2 may be arranged between the image display periods DIS. In one embodiment, the first sensing period SEN1 may be set to a predetermined frame period. Similarly, the second sensing period SEN2 may be set to a predetermined frame period.

The first sensing period SEN1 is a period during which the first sensing current flowing in the driving transistor TD is detected. Therefore, the threshold voltage characteristic and the mobility characteristic of the driving transistor TD can 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 intervals of 2n frames, and the first sensing current may be detected at intervals of 2n frames. However, this is only 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 during which the second sensing current flowing in the organic light emitting diode EL is detected. Therefore, deterioration of the organic light emitting diode EL or the like can 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 intervals of 2n frames, and the second sensing current may be detected in real time at intervals of 2n frames. However, this is only 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.

In addition, 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's command.

FIG. 9 is a block diagram illustrating an electronic device according to an embodiment of the present invention. FIG. 10A is a diagram illustrating an example in which the electronic device of FIG. 9 is implemented by a television, As shown in FIG.

9 through 10B, an 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 1060 ). At this time, the organic light emitting display 1060 may correspond to the organic light emitting display 100, 101 of FIG. 1 or FIG. The electronic device 1000 may further include a plurality of ports capable of communicating with, or communicating with, video cards, sound cards, memory cards, USB devices, and the like. 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 exemplary one, and the electronic device 1000 is not limited thereto. For example, the electronic device 1000 may be a mobile phone, a video phone, a smart pad, a smart watch, a tablet PC, a car navigation system, a computer monitor, a notebook, a head mounted display ; HMD) or the like.

Processor 1010 may perform certain calculations or tasks. In accordance with an embodiment, the processor 1010 may be a microprocessor, a central processing unit, an application processor, or the like. The processor 1010 may be coupled to other components via an address bus, a control bus, and a data bus. In accordance with an embodiment, the processor 1010 may also be coupled to an expansion bus, such as a Peripheral Component Interconnect (PCI) bus. The memory device 1020 may store data necessary for operation of the electronic device 1000. [ For example, the memory device 1020 may be an erasable programmable read-only memory (EPROM) device, an electrically erasable programmable read-only memory (EEPROM) device, a flash memory device, (PRAM) device, a Resistance Random Access Memory (RRAM) device, a Nano Floating Gate Memory (NFGM) device, a Polymer Random Access Memory (PoRAM) device, a Magnetic Random Volatile memory devices and / or dynamic random access memory (DRAM) devices such as MRAM, Ferroelectric Random Access Memory (MRAM) DRAM devices, and the like. 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 input means such as a keyboard, a keypad, a touch pad, a touch screen, a mouse and the like, and output means such as a speaker, a printer and the like. The power supply 1050 can supply the power required for the operation of the electronic device 1000.

The organic light emitting display 1060 may be coupled to other components via the buses or other communication links. According to an embodiment, the organic light emitting diode display 1060 may be included in the input / output device 1040. As described above, the OLED display 1060 can operate in a video display mode and a sensing mode. To this end, the OLED display 1060 includes a display panel including a plurality of pixel circuits, a data driver for supplying a data voltage to the display panel, a scan driver for providing a scan signal to the display panel, A global gate driver for providing signals (e.g., a sensing control signal and a light emission control signal), a controller for analyzing a sensing current output from the pixel circuits to compensate for the data voltage, And a power supply unit for supplying the second power supply voltage.

The present invention can be applied to a display device for performing a pixel current sensing operation and an electronic device having the same. For example, the present invention can be applied to a television, a personal computer, a notebook, a tablet, a mobile phone, a smart phone, a smart pad, a PDA, a PMP, a digital camera, an MP3 player, a portable game console,

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the following claims. It can be understood that it is possible.

10, 11: pixel circuits 100, 101: organic light emitting display
110, 111: display panel 120, 121: scan driver
130, 131: Global gate driver 140, 141: Data driver
150, 151: a control unit 160, 161:

Claims (20)

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 to be connected to a first node;
A driving transistor including a gate electrode coupled to the first node, a first electrode coupled to a second node, and a second electrode coupled 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 coupled to the first node, and a second electrode coupled to the second node;
A second sensing switch having a gate electrode to which a second sensing control signal is applied, a first electrode coupled to the third node, and a second electrode coupled to the second power supply;
A light emission control switch having a gate electrode to which a light emission control signal is applied, a first electrode connected to the first power supply, and a second electrode connected to the second node; And
A storage capacitor coupled between the first node and the third node,
A pixel circuit driven in a video display mode and a sensing mode. 2. The pixel circuit of claim 1, wherein the first sensing control signal and the light emission control signal each correspond to a global gate signal. The method of claim 2, wherein the second sensing control signal corresponds to the scan signal, the scan switch and the second sensing switch are simultaneously controlled,
Wherein the image display mode is a simultaneous light emission mode or a sequential light emission mode when the second sensing control signal corresponds to the scan signal. The pixel circuit according to claim 3, wherein in the sensing mode, the first sensing switch maintains a turn-on state, and the light emission control switch maintains a turn-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 according to claim 4, wherein, in the sensing mode, when the scan switch and the second sensing switch are turned on, a sensing current flowing in the data line is detected based on the gate- . The pixel circuit according to claim 3, wherein in the sequential light emission mode, the first sensing switch maintains the turn-off state, and the light emission control switch maintains the turn-on state. 4. The method of claim 3, wherein the simultaneous light emission mode includes a write period and a simultaneous light emission period,
The light emission control switch is turned off in the writing period, turned on in the simultaneous light emission period,
And the first sensing switch maintains a turn-off state in the simultaneous light emission mode. 2. The method of claim 1, wherein each of the first sensing control signal, the second sensing control signal, and the light emission control signal corresponds to a global gate signal,
Wherein 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 sensing deterioration characteristics of the organic light emitting diode,
Wherein the video display mode corresponds to a simultaneous light emission mode. 10. The pixel circuit according to claim 9, wherein in the first sensing mode, the first sensing switch and the second sensing switch maintain the turn-on state, and the light emission control switch maintains the turn-off state. 11. The pixel circuit according to claim 10, wherein in the first sensing mode, the first and second sensing control signals have a logic high level and the light emission control signal has a logic low level. . 10. The pixel circuit according to claim 9, wherein in the second sensing mode, the first sensing switch maintains the turn-on state, and the second sensing switch and the light emission control switch maintain the turn-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 light emission control signal has a logic low level . 13. The pixel circuit according to 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 driven by a video display mode or a sensing mode and having a plurality of pixel circuits each connected to a scan line, a data line, a first sensing control line, a second sensing control line, and a light emission control line, respectively;
A scan driver for supplying a scan signal to the scan line;
A global gate driver for providing a first sensing control signal to the first sensing control line and providing a light emission control signal to the light emitting control line;
A data driver for providing a data voltage to the data line based on image data;
A control unit for analyzing a sensing current flowing through each of the pixel circuits through the data line to compensate the data voltage or the image data; And
And a power supply unit for supplying the display panel with a second power source having a voltage level lower than that of the first power source and the first power source,
Each of the plurality of pixel circuits comprising:
An organic light emitting diode having a cathode connected to the second power supply;
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 to be connected to the first node;
A driving transistor including a gate electrode coupled to the first node, a first electrode coupled to a second node, and a second electrode coupled to a third node corresponding to the anode of the organic light emitting diode;
A first sensing switch coupled to the first sensing control line and having a gate electrode receiving the first sensing control signal, a first electrode coupled to the first node, and a second electrode coupled to the second node;
A second sensing switch coupled to the second sensing control line and having a gate electrode receiving the second sensing control signal, a first electrode coupled to the third node, and a second electrode coupled to the second power supply;
A light emitting control switch connected to the emission control line and having a gate electrode to which the emission control signal is applied, a first electrode connected to the 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 light emission control signal correspond to a global gate signal, the second sensing control signal corresponds to the scan signal,
Wherein the image display mode is a simultaneous light emission mode or a sequential light emission mode. The driving method according to 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, The organic light emitting display device comprising: 16. The method of claim 15, wherein the global gate driver provides the second sensing signal to the second sensing control line,
Wherein the first sensing control signal, the second sensing control signal, and the light emission control signal correspond to a global gate signal, respectively,
Wherein 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,
Wherein the image display mode operates in a simultaneous light emission mode. 19. The organic light emitting diode display according to claim 18, wherein in the first sensing mode, the first sensing switch and the second sensing switch maintain a turn-on state, and the light emission control switch maintains a turn- . 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 emission control switch maintain a turn-off state, and when the scan switch is turned on And the sensing current flowing in the organic light emitting diode is detected.

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