KR100821041B1 - Organic light emitting display device and driving method thereof - Google Patents

Abstract

An OLED device and a driving method thereof are provided to compensate for the deterioration of an organic light emitting diode by adjusting the voltage of a gate electrode of a driving transistor. An OLED(Organic Light Emitting Display) device includes pixels formed at a cross section of scan and data lines, a scan driver, and a data driver for sinking currents. Each of pixels includes an organic light emitting diode(OLED), a driver(242), and a compensator(244). The driver includes a driving transistor which charges voltages corresponding to sunk currents and supplies currents corresponding to the charged voltages to the organic light emitting diode. The compensator controls the voltage of a gate electrode of the driving transistor corresponding to the deterioration of the organic light emitting diode.

Description

Organic Light Emitting Display Device and Driving Method Thereof}

1 is a circuit diagram illustrating a pixel of a conventional organic light emitting display device.

2 is a diagram illustrating an organic light emitting display device according to an exemplary embodiment of the present invention.

3 is a diagram illustrating an example embodiment of a pixel illustrated in FIG. 2.

4 is a diagram illustrating a first embodiment of the compensator shown in FIG. 3.

FIG. 5 is a waveform diagram illustrating a method of driving the pixel illustrated in FIG. 4.

FIG. 6 is a diagram illustrating a second embodiment of the compensator shown in FIG. 3.

FIG. 7 is a diagram illustrating a third embodiment of the compensator shown in FIG. 3.

8 is a diagram illustrating another embodiment of the driving unit illustrated in FIG. 3.

<Explanation of symbols for the main parts of the drawings>

2: pixel circuit 4: pixel

210: scan driver 220: data driver

230: pixel portion 240: pixel

242: drive unit 244: compensation unit

250: timing controller

The present invention relates to an organic light emitting display device and a driving method thereof, and more particularly, to an organic light emitting display device and a driving method thereof capable of compensating degradation of an organic light emitting diode.

Recently, various flat panel displays have been developed to reduce weight and volume, which are disadvantages of cathode ray tubes. The flat panel display includes a liquid crystal display, a field emission display, a plasma display panel, and an organic light emitting display.

Among flat panel displays, an organic light emitting display device displays an image using an organic light emitting diode that generates light by recombination of electrons and holes. Such an organic light emitting display device has an advantage of having a fast response speed and being driven with low power consumption.

1 is a circuit diagram illustrating a pixel of a conventional organic light emitting display device.

Referring to FIG. 1, a pixel 4 of a conventional organic light emitting display device is connected to an organic light emitting diode OLED, a data line Dm, and a scanning line Sn to control the organic light emitting diode OLED. The pixel circuit 2 is provided.

The anode electrode of the organic light emitting diode OLED is connected to the pixel circuit 2, and the cathode electrode is connected to the second power source ELVSS. Such an organic light emitting diode (OLED) generates light having a predetermined brightness in response to a current supplied from the pixel circuit 2.

The pixel circuit 2 controls the amount of current supplied to the organic light emitting diode OLED corresponding to the data signal supplied to the data line Dm when the scan signal is supplied to the scan line Sn. To this end, the pixel circuit 2 includes a second transistor M2 connected between the first power supply ELVDD and the organic light emitting diode OLED, the second transistor M2, the data line Dm, and the scan line Sn. And a first capacitor M1 connected between the first transistor M1 and a storage capacitor Cst connected between the gate electrode and the first electrode of the second transistor M2.

The gate electrode of the first transistor M1 is connected to the scan line Sn, and the first electrode is connected to the data line Dm. The second electrode of the first transistor M1 is connected to one terminal of the storage capacitor Cst. Here, the first electrode is set to any one of a source electrode and a drain electrode, and the second electrode is set to an electrode different from the first electrode. For example, when the first electrode is set as the source electrode, the second electrode is set as the drain electrode. The first transistor M1 connected to the scan line Sn and the data line Dm is turned on when a scan signal is supplied from the scan line Sn to receive a data signal supplied from the data line Dm to the storage capacitor Cst. ). In this case, the storage capacitor Cst charges a voltage corresponding to the data signal.

The gate electrode of the second transistor M2 is connected to one terminal of the storage capacitor Cst, and the first electrode is connected to the other terminal of the storage capacitor Cst and the first power supply ELVDD. The second electrode of the second transistor M2 is connected to the anode electrode of the organic light emitting diode OLED. The second transistor M2 controls the amount of current flowing from the first power source ELVDD to the second power source ELVSS via the organic light emitting diode OLED in response to the voltage value stored in the storage capacitor Cst. In this case, the organic light emitting diode OLED generates light corresponding to the amount of current supplied from the second transistor M2.

However, such a conventional organic light emitting display device has a problem in that it is impossible to display an image having a desired brightness due to a change in efficiency caused by deterioration of the organic light emitting diode OLED. In other words, as time passes, organic light emitting diodes included in each of the red, green, and blue pixels deteriorate, and thus an image having a desired luminance cannot be displayed. In fact, as the organic light emitting diode deteriorates, light of low luminance is generated.

Accordingly, it is an object of the present invention to provide an organic light emitting display device and a driving method thereof capable of compensating for degradation of an organic light emitting diode.

In order to achieve the above object, an organic light emitting display device according to an exemplary embodiment of the present invention comprises: pixels positioned at an intersection of scan lines and data lines; A scan driver for sequentially supplying scan signals to the scan lines; A data driver for sinking current from the pixels selected for the scan signal via the data line; Each of the pixels comprises an organic light emitting diode; A driving unit including a driving transistor for charging a voltage corresponding to the sinked current when the current is sinked and supplying a current corresponding to the charged voltage to the organic light emitting diode; And a compensation unit for controlling the voltage of the gate electrode of the driving transistor in response to deterioration of the organic light emitting diode.

Preferably, the driving unit includes a first transistor connected to the scan line and the data line and turned on when a scan signal is supplied to the scan line; The driving transistor connected between a first power supply and the organic light emitting diode and having a gate electrode connected to a second electrode of the first transistor; A second transistor connected between the second electrode of the driving transistor and the data line and turned on when a scan signal is supplied to the scan line; A storage capacitor charging a voltage corresponding to the current flowing in the driving transistor when the current is sinked in the data driver; And a fourth transistor connected between the driving transistor and the organic light emitting diode and turned off for at least a period during which the scan signal is supplied. The compensation unit includes a feedback connected between a fifth transistor and a sixth transistor positioned between a compensation power supply and an anode electrode of the organic light emitting diode, a common node of the fifth and sixth transistors, and a gate electrode of the driving transistor. With a capacitor.

A method of driving an organic light emitting display device according to an embodiment of the present invention includes a first step of controlling a current to flow through a driving transistor when a scan signal is supplied and charging a voltage corresponding to the current flowing through the driving transistor; And a second step of maintaining the other terminal of the feedback capacitor, the one terminal of which is connected to the gate electrode of the driving transistor, as the threshold voltage of the organic light emitting diode during the first step, and after the supply of the scan signal is stopped. And raising a voltage of the other terminal of the capacitor to the voltage of the compensation power supply.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 2 to 8 that can be easily implemented by those skilled in the art.

2 is a diagram illustrating an organic light emitting display device according to an exemplary embodiment of the present invention.

Referring to FIG. 2, in the organic light emitting display device according to an exemplary embodiment of the present invention, scan lines S1 to Sn, first control lines CL11 to CL1n, second control lines CL21 to CL2n, and data lines A pixel unit 230 including pixels 240 positioned to be connected to D1 to Dm, scan lines S1 to Sn, first control lines CL11 to CL1n, and second control lines CL21 to CL2n. ), A data driver 220 for driving the data lines D1 to Dm, a timing controller 250 for controlling the scan driver 210 and the data driver 220. It is provided.

The scan driver 210 receives a scan driving control signal SCS from the timing controller 250. The scan driver 210 receiving the scan driving control signal SCS generates a scan signal and sequentially supplies the generated scan signal to the scan lines S1 to Sn. In addition, the scan driver 210 generates a first control signal and a second control signal in response to the scan driving control signal SCS. The first control signal generated by the scan driver 210 is sequentially supplied to the first control lines CL11 to CL1n, and the second control signal is sequentially supplied to the second control lines CL21 to CL2n.

Here, the widths of the first control signal and the second control signal are set to be wider than the width of the scan signal. In practice, the first and second control signals supplied to the i-th first control line CL1i and the second control line CL2i are supplied to overlap with the scan signals supplied to the i-th scan line Si. do. The first and second control signals supplied to the i-th first control line CL1i and the second control line CL2i are supplied at the same timing and have inverted polarities.

The data driver 220 receives a data driving control signal DCS and data Data from the timing controller 250. The data driver 220 receiving the data driving control signal DCS and the data Data generates a data signal having a predetermined current, and supplies a current corresponding to the generated data signal through the data lines D1 to Dm. Sinks from the field 240. In other words, the data driver 220 sinks a current corresponding to the data signal from the pixels 240 selected by the scan signal.

The timing controller 250 generates a data driving control signal DCS and a scan driving control signal SCS in response to synchronization signals supplied from the outside. The data driving control signal DCS generated by the timing controller 250 is supplied to the data driver 220, and the scan driving control signal SCS is supplied to the scan driver 210. In addition, the timing controller 250 supplies the data Data supplied from the outside to the data driver 220.

The pixel unit 230 receives the first power source ELVDD, the second power source ELVSS, and the compensation power source Vsus from the outside, and supplies them to the pixels 240. The pixels 240 supplied with the first power source ELVDD, the second power source ELVSS, and the compensation power source Vsus receive a predetermined voltage in response to a current that is sinked from the data driver 220 when a scan signal is supplied. To charge. In addition, the pixels 240 control the voltage of the gate electrode of the driving transistor so that degradation of the organic light emitting diode can be compensated for, and in response to the controlled voltage, the pixels 240 receive the second voltage from the first power source ELVDD via the organic light emitting diode. The amount of current flowing to the power supply ELVSS is controlled.

3 is a circuit diagram illustrating a pixel according to an exemplary embodiment of the present invention. 3 illustrates a pixel connected to the nth scan line and the mth data line Dm for convenience of description.

Referring to FIG. 3, a pixel 240 according to an exemplary embodiment of the present invention includes an organic light emitting diode (OLED) and a driver for charging a voltage corresponding to a current sinked in the data driver 220 when a scan signal is supplied. 242 and a compensation unit 244 for compensating for degradation of the organic light emitting diode OLED.

The anode of the organic light emitting diode OLED is connected to the driver 242 and the compensator 244, and the cathode is connected to the second power source ELVSS. The organic light emitting diode OLED generates light having a predetermined luminance in response to a current supplied from the driver 242.

The driving unit 242 includes a third transistor M3 (or a driving transistor) for controlling the amount of current supplied to the organic light emitting diode OLED, a scan line Sn, a data line Dm, and a third transistor M3. The first transistor M1 connected to the gate electrode, the second transistor M2 connected to the second electrode of the scan line Sn, the data line Dm, and the third transistor M3, and the data driver 220. A storage capacitor (Cst) for charging a voltage corresponding to the current of the data signal to be sinked in.

The gate electrode of the first transistor M1 is connected to the scan line Sn, and the first electrode is connected to the data line Dm. The second electrode of the first transistor M1 is connected to the gate electrode of the third transistor M3. The first transistor M1 electrically connects the data line Dm and the gate electrode of the third transistor M3 when a scan signal is supplied to the scan line Sn.

The gate electrode of the second transistor M2 is connected to the scan line Sn, and the first electrode is connected to the second electrode of the third transistor M3. The second electrode of the second transistor M2 is connected to the data line Dm. The second transistor M2 electrically connects the data line Dm and the second electrode of the third transistor M2 when a scan signal is supplied to the scan line Sn. That is, the second transistor M2 is turned on when the scan signal is supplied so that the current path can be supplied to the data line Dm via the first power source ELVDD and the third transistor M3. to provide.

The gate electrode of the third transistor M3 is connected to the second electrode of the first transistor M1, and the first electrode is connected to the first power source ELVDD. The second electrode of the third transistor M3 is connected to the first electrode of the second transistor M2 and the first electrode of the fourth transistor M4. The third transistor M3 controls the amount of current flowing from the first power source ELVDD to the second power source ELVSS via the organic light emitting diode OLED in response to the voltage applied to its gate electrode. To this end, the voltage value of the first power supply ELVDD is set higher than the voltage value of the second power supply ELVSS.

The gate electrode of the fourth transistor M4 is connected to the first control line CL1n, and the first electrode is connected to the second electrode of the third transistor M3. The second electrode of the fourth transistor M4 is connected to the anode electrode of the organic light emitting diode OLED. The fourth transistor M4 is turned off when the first control signal is supplied, and is turned on in other cases. Here, the polarity of the first control signal is set opposite to that of the scan signal.

One terminal of the storage capacitor Cst is connected to the gate electrode of the third transistor M3, and the other terminal of the storage capacitor Cst is connected to the first power source ELVDD. The storage capacitor Cst charges a predetermined voltage in response to a current sinked into the data line Dm when the first transistor and the second transistor M2 are turned on.

The compensator 244 connected to the first control line CL1n and the second control line CL2n and supplied with the compensation power supply Vsus is configured to respond to deterioration of the organic light emitting diode OLED. The voltage of the gate electrode is controlled. In other words, the compensator 244 controls the voltage of the gate electrode of the third transistor M3 to compensate for the degradation of the organic light emitting diode OLED.

The compensation power supply Vsus is set to a voltage value higher than the threshold voltage OLED_Vth of the organic light emitting diode OLED so that degradation of the organic light emitting diode OLED can be compensated for. In addition, the compensation power supply Vsus is set lower than the voltage value of the first power supply ELVDD so that sufficient light can be generated in the organic light emitting diode OLED. On the other hand, as the OLED degrades, the threshold voltage OLED_Vth of the OLED increases.

4 is a diagram illustrating a first embodiment of the compensator shown in FIG. 3.

Referring to FIG. 4, the compensator 244 includes a fifth transistor M5, a sixth transistor M6, and a fifth transistor positioned between the compensation power supply Vsus and the anode electrode of the organic light emitting diode OLED. A feedback capacitor Cfb is disposed between the first node N1 and the gate electrode of the third transistor M3, which are common nodes of the M5 and the sixth transistors M6.

The fifth transistor M5 is positioned between the first node N1 and the anode of the organic light emitting diode OLED, and is controlled by a second control signal supplied from the second control line CL2n.

The sixth transistor M6 is positioned between the first node N1 and the compensation power supply Vsus, and is controlled by the first control signal supplied from the first control line CL1n.

The feedback capacitor Cfb transfers the voltage change amount of the first node N1 to the gate electrode of the third transistor M3.

5 is a diagram illustrating a driving method of the pixel illustrated in FIG. 4.

4 and 5, the operation process will be described in detail. First, the first control signal high and the second control signal low are supplied to the first control line CL1n and the second control line CL2n. . When the first control signal is supplied, the fourth transistor M4 and the sixth transistor M6 are turned off. When the second control signal is supplied, the fifth transistor M5 is turned on.

When the fifth transistor M5 is turned on, the first node N1 is electrically connected to the anode electrode of the organic light emitting diode OLED. Therefore, the voltage of the first node N1 is set to the threshold voltage OLED_Vth of the organic light emitting diode OLED.

Thereafter, the scan signal is supplied to the scan line Sn to turn on the first transistor M1 and the second transistor M2. In this case, the current is supplied to the data line Dm via the first power source ELVDD, the third transistor M3, and the second transistor M2 in response to the current sinked from the data driver 220. Then, a predetermined voltage is applied to the gate electrode of the third transistor M3 corresponding to the current flowing through the third transistor M3, and the voltage corresponding to the applied voltage is charged in the storage capacitor Cst. After the voltage corresponding to the data signal is charged in the storage capacitor Cst, the supply of the scan signal is stopped to turn off the first transistor M1 and the second transistor M2.

After the first transistor M1 and the second transistor M2 are turned off, the supply of the first control signal and the second control signal is stopped. When the supply of the second control signal is stopped, the fifth transistor M5 is turned off. When the supply of the first control signal is stopped, the fourth transistor M4 and the sixth transistor M6 are turned on.

When the sixth transistor M6 is turned on, the voltage of the first node N1 increases from the threshold voltage OLED_Vth of the organic light emitting diode to the voltage of the compensation power supply Vsus. At this time, the voltage of the gate electrode of the third transistor M3 also increases in response to the increase of the voltage of the first node N1. In practice, the voltage rise of the gate electrode of the third transistor M3 is determined as in Equation (1).

ΔV _{M3 _gate} = ΔV _N1 × (Cfb / (Cst + Cfb))

In Equation 1, ΔV _{M3 _gate} means a voltage change amount of the third transistor M3 gate electrode, and ΔV _N1 means a voltage change amount of the first node N1.

Referring to Equation 1, the voltage applied to the gate electrode of the third transistor M3 is changed corresponding to the voltage change amount of the first node N1. That is, when the voltage of the first node N1 increases, the voltage of the gate electrode of the third transistor M3 also increases. Thereafter, the third transistor M3 supplies a current corresponding to the voltage applied to its gate electrode from the first power supply ELVDD to the second power supply ELVSS via the organic light emitting diode OLED. Then, in the organic light emitting diode OLED, light having a predetermined luminance is generated corresponding to the current supplied from the third transistor M3.

On the other hand, the organic light emitting diode OLED deteriorates with time. Here, as the OLED degrades, the threshold voltage OLED_Vth of the OLED increases. When the threshold voltage OLED_Vth of the organic light emitting diode rises, the voltage rising width of the first node N1 decreases. In other words, as the OLED degrades, the threshold voltage OLED_Vth of the organic light emitting diode supplied to the first node N1 increases, so that the voltage rise of the first node N1 increases. (OLED) is set lower than when it is not degraded. Therefore, as the organic light emitting diode OLED deteriorates, the amount of current supplied from the third transistor M3 to the organic light emitting diode OLED increases in response to the same data signal. That is, in the present invention, as the organic light emitting diode (OLED) deteriorates, the amount of current supplied from the third transistor (M3) to the organic light emitting diode (OLED) is increased to compensate for the decrease in luminance due to degradation of the organic light emitting diode (OLED). have.

Meanwhile, the red organic light emitting diode OLED (R) included in the red pixel, the green organic light emitting diode OLED (G) included in the green pixel, and the blue organic light emitting diode OLED (B) included in the blue pixel are It is formed of different materials and therefore has different life characteristics. In fact, the red organic light emitting diode OLED (R), the green organic light emitting diode OLED (G), and the blue organic light emitting diode OLED (B) have lifetime characteristics as shown in Equation (2).

OLED (B) <OLED (R) <OLED (G)

Referring to Equation 2, the life characteristics of the green organic light emitting diode OLED (G) are the best, and the blue organic light emitting diode OLED (B) is set the worst. In the present invention, the capacitance of the feedback capacitor Cfb may be set differently in each of the red pixel, the green pixel, and the blue pixel to compensate for such life characteristics.

For example, in the present invention, the capacitance of the feedback capacitor Cfb may be set larger as it is included in a pixel having a low lifespan. That is, the capacitance of the feedback capacitor Cfb included in the blue pixel is set to the largest value, and the capacitance of the feedback capacitor Cfb included in the green pixel is set to the lowest. Meanwhile, the capacitance of the feedback capacitor Cfb included in each of the red pixel, the green pixel, and the blue pixel is not limited thereto. In practice, the capacitance of the feedback capacitor Cfb is determined experimentally so that degradation can be best compensated for in response to the material properties of the organic light emitting diode OLED used for each of the red, green and blue pixels.

FIG. 6 is a diagram illustrating a second embodiment of the compensator shown in FIG. 3. 6, detailed description of the same configuration as that of FIG. 4 will be omitted.

Referring to FIG. 6, the compensation unit 244 according to the second embodiment of the present invention may include the fifth transistor M5 and the sixth transistor positioned between the compensation power Vsus and the anode electrode of the organic light emitting diode OLED. And a feedback capacitor Cfb positioned between the transistor M6 and the gate electrode of the first node N1 and the third transistor M3.

The fifth transistor M5 is positioned between the first node N1 and the anode electrode of the organic light emitting diode OLED and controlled by the first control signal supplied to the first control line CL1n. Here, the fifth transistor M5 is set as an NMOS transistor. That is, the fifth transistor M5 is set to a different conductivity type from the transistors M1, M2, M3, M4, and M6 included in the pixel 240. Therefore, the fifth transistor M5 is turned on when the first control signal is supplied, and is otherwise turned off.

The sixth transistor M6 is positioned between the first node N1 and the voltage source Vsus, and is controlled by the first control signal supplied from the first control line CL1n. Here, the sixth transistor M6 is turned off when the first control signal is supplied, and is turned on in other cases.

As described above, in the compensator 244 according to the second embodiment of the present invention, the fifth transistor M5 is formed of an NMOS, and thus, the second control line CL2n can be removed.

5, the first control signal is first supplied to the first control line CL1n. When the first control signal is supplied, the sixth transistor M6 and the fourth transistor M4 are turned off, and the fifth transistor M5 is turned on.

When the fifth transistor M5 is turned on, the first node N1 is electrically connected to the anode electrode of the organic light emitting diode OLED. Therefore, the voltage of the first node N1 is set to the threshold voltage OLED_Vth of the organic light emitting diode OLED.

Thereafter, the scan signal is supplied to the scan line Sn to turn on the first transistor M1 and the second transistor M2. In this case, the current is supplied to the data line Dm via the first power source ELVDD, the third transistor M3, and the second transistor M2 in response to the current sinked from the data driver 220. Then, a predetermined voltage is applied to the gate electrode of the third transistor M3 corresponding to the current flowing through the third transistor M3, and the voltage corresponding to the applied voltage is charged in the storage capacitor Cst. After the voltage corresponding to the data signal is charged in the storage capacitor Cst, the supply of the scan signal is stopped to turn off the first transistor M1 and the second transistor M2.

After the first transistor M1 and the second transistor M2 are turned off, the supply of the first control signal is stopped. When the supply of the first control signal is stopped, the fifth transistor M5 is turned off and the fourth transistor M4 and the sixth transistor M6 are turned on.

When the sixth transistor M6 is turned on, the voltage of the first node N1 increases from the threshold voltage OLED_Vth of the organic light emitting diode to the voltage of the compensation power supply Vsus. At this time, the voltage of the gate electrode of the third transistor M3 also increases in response to the increase of the voltage of the first node N1. In this case, the gate electrode voltage rising width of the third transistor M3 is determined to correspond to the deterioration of the organic light emitting diode OLED, thereby compensating for the deterioration of the organic light emitting diode OLED.

FIG. 7 is a diagram illustrating a third embodiment of the compensator shown in FIG. 3. Detailed description of the same configuration as in FIG. 4 in FIG. 7 will be omitted.

Referring to FIG. 7, the compensation unit 244 according to the third embodiment of the present invention may include a fifth transistor M5 and a sixth transistor positioned between the compensation power supply Vsus and the anode electrode of the organic light emitting diode OLED. A feedback capacitor Cfb positioned between M6 and the gate electrode of the first node N1 and the third transistor M3 is provided.

The fifth transistor M5 is positioned between the first node N1 and the anode electrode of the organic light emitting diode OLED, and is controlled by the scan signal supplied from the scan line Sn. That is, the fifth transistor M5 is turned on when the scan signal is supplied and is turned off when the scan signal is not supplied.

The sixth transistor M6 is positioned between the first node N1 and the compensation power supply Vsus. The sixth transistor M6 is controlled by the first control signal supplied to the first power line CL1n.

The compensation unit 9244 according to the third embodiment of the present invention can remove the second control signal CL2n as compared with FIG. 4. In other words, the compensator 244 according to the third embodiment of the present invention is connected to the scan line Sn and the first control line CL1n to compensate for deterioration of the organic light emitting diode OLED.

The operation process will be described in detail using the scan signal and the first control signal shown in FIG. 5. First, the first control signal is supplied to the first control line CL1n. When the first control signal is supplied, the fourth transistor M4 and the sixth transistor M6 are turned off.

Thereafter, the scan signal is supplied to the scan line Sn to turn on the first transistor M1, the second transistor M2, and the fifth transistor M5. When the first transistor M1 and the second transistor M2 are turned on, a voltage corresponding to a current sinked from the data driver 220 is charged in the storage capacitor Cst. When the fifth transistor M5 is turned on, the threshold voltage OLED_Vth of the organic light emitting diode is supplied to the first node N1. After the predetermined voltage is charged in the storage capacitor Cst, the supply of the scan signal is stopped to turn off the first transistor M1, the second transistor M2, and the fifth transistor M5.

After the first transistor M1, the second transistor M2, and the fifth transistor M5 are turned off, the supply of the first control signal is stopped. When the supply of the first control signal is stopped, the fourth transistor M4 and the sixth transistor M6 are turned on.

When the sixth transistor M6 is turned on, the voltage of the first node N1 increases from the threshold voltage OLED_Vth of the organic light emitting diode to the voltage of the compensation power supply Vsus. When the voltage of the first node N1 increases, the gate electrode voltage of the third transistor M3 also increases by the feedback capacitor Cfb. Here, since the gate electrode voltage rising width of the third transistor M3 is determined to correspond to the degradation of the organic light emitting diode OLED, the degradation of the organic light emitting diode OLED can be compensated for.

As described above, the configuration of the compensator 244 may be variously set in the present invention. In fact, when the voltage is charged in the storage capacitor Cst, the voltage of the first node N1 is maintained at the threshold voltage OLED_Vth of the organic light emitting diode, and after the voltage is charged in the storage capacitor Cst, the first node ( The configuration of the compensation unit 244 may be variously set so that the voltage of N1) may be raised to the compensation power supply Vsus.

8 is a view showing another embodiment of the drive unit of the present invention. When describing FIG. 8, detailed description of the same configuration as FIG. 3 will be omitted.

Referring to FIG. 8, in the driving unit 242 according to another embodiment of the present invention, the second transistor M2 ′ is positioned between the second electrode and the gate electrode of the third transistor M3.

In detail, the gate electrode of the second transistor M2 'is connected to the scan line Sn, and the first electrode is connected to the second electrode of the third transistor M3. The second electrode of the second transistor M2 'is connected to the gate electrode of the third transistor M3. The second transistor M2 'electrically connects the second electrode and the gate electrode of the second transistor M2' when the scan signal is supplied to the scan line Sn.

Referring to the operation, when the scan signal is supplied to the scan line Sn, the first transistor M1 and the second transistor M2 'are turned on. When the first transistor M1 is turned on, the gate electrode of the third transistor M3 and the data line Dm are electrically connected to each other. When the second transistor M2 'is turned on, the second electrode and the gate electrode of the third transistor M3 are electrically connected to each other.

Then, the current sinked from the data driver 220 is supplied to the data line Dm via the first power source ELVDD, the third transistor M3, the second transistor M2 ′, and the first transistor M1. do. In this case, the storage capacitor Cst charges a predetermined voltage in response to the current flowing through the third transistor M3. Other driving methods are the same as in FIG. 3, so a detailed description thereof will be omitted.

Meanwhile, in the present invention, the driver 242 may be set to various structures capable of charging a voltage corresponding to the current that is sinked to the storage capacitor Cst when the current is sinked in the data driver 220.

The above detailed description and drawings are merely exemplary of the present invention, but are used only for the purpose of illustrating the present invention and are not intended to limit the scope of the present invention as defined in the meaning or claims. Accordingly, those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical protection scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

As described above, the organic light emitting display device and the driving method thereof according to the exemplary embodiment of the present invention can compensate for the degradation of the organic light emitting diode by controlling the gate electrode voltage of the driving transistor in response to the degradation of the organic light emitting diode. . In addition, in the present invention, since the storage capacitor is charged in response to the current sinked in the data driver, a uniform image may be displayed regardless of the threshold voltage and mobility of the driving transistor.

Claims (20)

Pixels positioned at the intersection of the scan lines and the data lines; A scan driver for sequentially supplying scan signals to the scan lines; A data driver for sinking current from the pixels selected for the scan signal via the data line; Each of the pixels An organic light emitting diode; A driving unit including a driving transistor for charging a voltage corresponding to the sinked current when the current is sinked and supplying a current corresponding to the charged voltage to the organic light emitting diode; And a compensation unit for controlling the voltage of the gate electrode of the driving transistor in response to deterioration of the organic light emitting diode. The method of claim 1, The driving unit A first transistor connected to the scan line and the data line and turned on when a scan signal is supplied to the scan line; The driving transistor connected between a first power supply and the organic light emitting diode and having a gate electrode connected to a second electrode of the first transistor; A second transistor connected between the second electrode of the driving transistor and the data line and turned on when a scan signal is supplied to the scan line; A storage capacitor charging a voltage corresponding to the current flowing in the driving transistor when the current is sinked in the data driver; And a fourth transistor connected between the driving transistor and the organic light emitting diode and turned off for at least a period during which the scan signal is supplied. The method of claim 2, And the fourth transistor is connected to a first control line connected in parallel with the scan line and is turned off when the first control signal is supplied to overlap the scan signal. The method of claim 1, The compensation unit A fifth transistor and a sixth transistor positioned between a compensation power supply and an anode electrode of the organic light emitting diode; And a feedback capacitor connected between the common node of the fifth and sixth transistors and the gate electrode of the driving transistor. The method of claim 4, wherein And the scan driver sequentially supplies the first control signal to the first control lines formed in parallel with the scan lines. The method of claim 5, The first control signal is set to be wider than the scan signal, and the first control signal supplied to the i (i is a natural number) th control line overlaps the scan signal supplied to the i th scan line. Organic electroluminescent display. The method of claim 6, And the scan driver sequentially supplies second control signals inverted in polarity with the first control signal to second control lines formed in parallel with the scan lines. The method of claim 7, wherein The second control signal is set to have a wider width than the scan signal, and the second control signal supplied to the i-th second control line overlaps the scan signal supplied to the i-th scan line. . The method of claim 8, And the fifth transistor is turned on when the second control signal is supplied, and the sixth transistor is turned off when the first control signal is supplied. The method of claim 9, And the feedback capacitor controls a voltage of a gate electrode of the driving transistor in response to an amount of change in voltage of the common node. The method of claim 6, And the fifth and sixth transistors are formed of different conductivity types. The method of claim 11, And the fifth transistor is turned on when the first control signal is supplied, and the sixth transistor is turned off when the first control signal is supplied. The method of claim 6, The fifth transistor is turned on when the scan signal is supplied, and the sixth transistor is turned off when the first control signal is supplied. The method of claim 4, wherein And the compensation power supply is set to a voltage value higher than the threshold voltage of the organic light emitting diode. The method of claim 1, The driving unit A first transistor connected to the scan line and the data line and turned on when a scan signal is supplied to the scan line; The driving transistor connected between a first power supply and the organic light emitting diode and having a gate electrode connected to a second electrode of the first transistor; A second transistor connected between the second electrode and the gate electrode of the driving transistor and turned on when a scan signal is supplied to the scan line; A storage capacitor charging a voltage corresponding to the current flowing in the driving transistor when the current is sinked in the data driver; And a fourth transistor connected between the driving transistor and the organic light emitting diode and turned off for at least a period during which the scan signal is supplied. The method of claim 4, wherein The pixel is divided into a red pixel including a red organic light emitting diode, a green pixel including a green organic light emitting diode, and a blue pixel including a blue organic light emitting diode, and the capacitance of the feedback capacitor is the red pixel, the green pixel, and the blue pixel. An organic light emitting display device, characterized in that differently set for each. A first step of controlling a current to flow through the driving transistor when a scan signal is supplied and charging a voltage corresponding to the current flowing in the driving transistor; A second step of maintaining the other terminal of the feedback capacitor having one terminal connected to the gate electrode of the driving transistor at the threshold voltage of the organic light emitting diode during the first step; And a third step of raising the voltage of the other terminal of the feedback capacitor to the voltage of the compensation power supply after the supply of the scan signal is stopped. The method of claim 17, And the driving transistor controls the amount of current flowing from the first power supply to the second power supply via the organic light emitting diode in response to a voltage applied to its gate electrode. The method of claim 18, The voltage value of the compensation power supply is set higher than the threshold voltage of the organic light emitting diode display device. The method of claim 18, And a voltage value of the compensation power supply is set to a voltage value less than or equal to the first power supply.

Images