KR100815756B1 - Pixel, organic light emitting display device and driving method thereof - Google Patents

Abstract

A pixel, an organic light emitting display device, and a driving method thereof are provided to compensate for an aging of RGB OLEDs by adjusting feedback capacitances in respective RGB pixels. A first transistor(M1) is connected to scan and data lines and turned on, when a scan signal is supplied to the scan line. A storage capacitor(Cst) is charged by a voltage corresponding to the data signal supplied to the data line. A second transistor(M2) supplies a current corresponding to the charged voltage in the storage capacitor from a first voltage source to a second voltage source through an OLED(OLED). A compensator(142) is connected to the voltage source whose voltage is higher than an anode voltage of the OLED, and controls the voltage of a gate electrode of the second transistor corresponding to an aging of the OLED(Organic Light Emitting Diode).

Description

Pixel, organic light emitting display device and driving method using same {Pixel, Organic Light Emitting Display Device and Driving Method Thereof}

1 is a circuit diagram showing a conventional pixel.

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 embodiment of a pixel illustrated in FIG. 2.

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

5 is a waveform diagram illustrating a driving method of 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.

FIG. 8 is a diagram illustrating a fourth embodiment of the compensator shown in FIG. 3.

FIG. 9 is a diagram illustrating a fifth embodiment of the compensator shown in FIG. 3.

FIG. 10 is a diagram illustrating a sixth embodiment of the compensator shown in FIG. 3.

FIG. 11 is a view illustrating a seventh embodiment of the compensator shown in FIG. 3.

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

2: pixel circuit 4: pixel

110: scan driver 120: data driver

130: pixel portion 140: pixel

142: compensation unit 150: timing control unit

The present invention relates to a pixel, an organic light emitting display device using the same, and a driving method thereof. More particularly, the present invention relates to a pixel, an organic light emitting display device using the same, and a method of driving the same.

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, an object of the present invention is to provide a pixel, an organic light emitting display device using the same, and a driving method thereof, which can compensate for deterioration of an organic light emitting diode.

In order to achieve the above object, a pixel according to an embodiment of the present invention is an organic light emitting diode; A first transistor connected to the scan line and the data line and turned on when the scan signal is supplied to the scan line; A storage capacitor for charging a voltage corresponding to the data signal supplied to the data line; A second transistor for supplying a current corresponding to the voltage charged in the storage capacitor from a first power supply to a second power supply via the organic light emitting diode; And a compensation unit connected to a voltage source having a voltage value higher than the voltage applied to the anode electrode of the organic light emitting diode and controlling the voltage of the gate electrode of the second transistor in response to deterioration of the organic light emitting diode.

In another embodiment, a pixel includes an organic light emitting diode; A first transistor connected to the scan line and the data line and turned on when the scan signal is supplied to the scan line; A storage capacitor for charging a voltage corresponding to the data signal supplied to the data line; A second transistor for supplying a current corresponding to the voltage charged in the storage capacitor from a first power supply to a second power supply via the organic light emitting diode; A third transistor and a fourth transistor positioned between the anode electrode of the organic light emitting diode and a voltage source having a voltage value higher than the voltage applied to the anode electrode of the organic light emitting diode; And a feedback capacitor positioned between the common node of the third and fourth transistors and the gate electrode of the second transistor.

An organic light emitting display device according to an exemplary embodiment of the present invention comprises: pixels positioned to be connected to scan lines and data lines; A scan driver for sequentially supplying scan signals to the scan lines; A data driver for driving the data lines; Each of the pixels comprises an organic light emitting diode; A first transistor connected to the scan line and the data line and turned on when the scan signal is supplied to the scan line; A storage capacitor for charging a voltage corresponding to the data signal supplied to the data line; A second transistor for supplying a current corresponding to the voltage charged in the storage capacitor from a first power supply to a second power supply via the organic light emitting diode; A third transistor and a fourth transistor positioned between the anode electrode of the organic light emitting diode and a voltage source having a voltage value higher than the voltage applied to the anode electrode of the organic light emitting diode; And a feedback capacitor positioned between the common node of the third and fourth transistors and the gate electrode of the second transistor.

A method of driving an organic light emitting display device according to an embodiment of the present invention includes charging a voltage corresponding to a data signal to a storage capacitor connected to a gate electrode of a driving transistor when a scan signal is supplied, and one terminal of the organic light emitting display device being driven. Maintaining the other terminal of the feedback capacitor connected to the gate electrode of the transistor at a voltage applied to the anode electrode of the organic light emitting diode during the period in which the voltage corresponding to the data signal is charged to the storage capacitor; Increasing the voltage of the other terminal of the feedback capacitor to the voltage of the voltage source after the supply is stopped.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 2 to 11 which 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, the organic light emitting display device according to an exemplary embodiment of the present invention includes scan lines S1 to Sn, first control lines CL11 to CL1n, second control lines CL21 to C2n, and data lines The pixel unit 130 including the pixels 140 positioned to be connected to D1 to Dm, the scan lines S1 to Sn, the first control lines CL11 to CL1n, and the second control lines CL21 to C2n. ), A data driver 120 for driving the data lines D1 to Dm, a timing controller 150 for controlling the scan driver 110 and the data driver 120. It is provided.

The scan driver 110 receives the scan driving control signal SCS from the timing controller 150. The scan driver 110 supplied with 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 110 generates a first control signal and a second control signal in response to the scan driving control signal SCS, and sequentially generates the first control signal through the first control lines CL11 to CL1n. At the same time, the second control signal is sequentially supplied to the second control lines CL21 to CL2n.

Here, the first control signal and the second control signal are set to a width wider than the width of the scan signal. In practice, the first control signal and the second control signal supplied to the i-th first control line CL1i and the second control line CL2i overlap with the scan signal supplied to the i-th scan line Si. The width is set as possible. Then, the first control signal and the second control signal are set to the same width, and the polarities are set opposite to each other.

The data driver 120 receives the data drive control signal DCS from the timing controller 150. The data driver 120 receiving the data driving control signal DCS generates a data signal and supplies the generated data signal to the data lines D1 to Dm in synchronization with the scan signal.

The timing controller 150 generates a data drive control signal DCS and a scan drive control signal SCS in response to external synchronization signals. The data driving control signal DCS generated by the timing controller 150 is supplied to the data driver 120, and the scan driving control signal SCS is supplied to the scan driver 110. The timing controller 150 supplies the data Data supplied from the outside to the data driver 120.

The pixel unit 130 receives the first power source ELVDD and the second power source ELVSS from the outside and supplies the same to the pixels 140. Each of the pixels 140 supplied with the first power source ELVDD and the second power source ELVSS generates light corresponding to the data signal. A compensation unit (not shown) is provided in each of the pixels 140 to compensate for deterioration of the organic light emitting diode.

3 is a circuit diagram illustrating a pixel according to an exemplary embodiment of the present invention. In FIG. 3, for convenience of description, the pixel connected to the nth scan line Sn and the mth data line Dm will be illustrated.

Referring to FIG. 3, a pixel 140 according to an exemplary embodiment of the present invention includes an organic light emitting diode OLED, a first transistor M1 connected to a scan line Sn and a data line Dm, and a storage capacitor. And a second transistor M2 for controlling the amount of current supplied to the organic light emitting diode OLED in response to the voltage charged in the Cst), and a compensating unit 142 for compensating for degradation of the organic light emitting diode OLED. do.

The anode electrode of the organic light emitting diode OLED is connected to the second transistor M2, and the cathode electrode 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 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 the gate electrode of the second transistor M2 (driving transistor). The first transistor M1 supplies the data signal supplied to the data line Dm to the gate electrode of the second transistor M2 when the scan signal is supplied to the scan line Sn.

The gate electrode of the second transistor M2 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 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 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.

One terminal of the storage capacitor Cst is connected to the gate electrode of the second transistor M2, and the other terminal of the storage capacitor Cst is connected to the first power source ELVDD. The storage capacitor Cst charges a voltage corresponding to the data signal when the first transistor M1 is turned on.

The compensator 142 controls the voltage of the gate electrode of the second transistor M2 in response to the deterioration of the organic light emitting diode OLED. In other words, the compensator 142 adjusts the voltage of the gate electrode of the second transistor M2 so that degradation of the organic light emitting diode OLED can be compensated for. To this end, the compensator 142 is connected to the voltage source Vsus, the first control line CL1n, and the second control line CL2n. The voltage value of the voltage source Vsus may be variously set so that degradation of the organic light emitting diode OLED may be compensated for. For example, the voltage value of the voltage source Vsus is set higher than the voltage Voled of the organic light emitting diode OLED. Here, the voltage Voled of the organic light emitting diode OLED is a voltage appearing at the anode electrode of the organic light emitting diode OLED, and the voltage value thereof changes in response to deterioration of the organic light emitting diode OLED. In addition, the voltage value of the voltage source Vsus is set to be equal to or less than the first power source ELVDD so that light of sufficient luminance can be generated in the pixel 140.

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

Referring to FIG. 4, the compensator 142 may include a third transistor M3, a fourth transistor M4, and a third transistor M3 positioned between the voltage source Vsus and the anode electrode of the organic light emitting diode OLED. And a feedback capacitor Cfb positioned between the first node N1 and the gate electrode of the second transistor M2, which are common nodes of the fourth transistor M4.

The third transistor M3 is positioned between the first node N1 and the anode electrode of the organic light emitting diode OLED and controlled by the second control signal supplied from the second control line CL2n.

The fourth transistor M4 is located 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.

The feedback capacitor Cfb transfers the voltage change amount of the first node N1 to the gate electrode of the second transistor M2.

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

4 and 5, the first operation signal (high voltage) is supplied to the first control line CL1n before the scan signal is supplied to the scan line Sn. The second control signal (low voltage) is supplied to the control line CL2n.

When the first control signal is supplied, the fourth transistor M4 is turned off, and when the second control signal is supplied, the third transistor M3 is turned on. In this case, the voltage Voled of the organic light emitting diode OLED is supplied to the first node N1.

Thereafter, the scan signal is supplied to the scan line Sn to turn on the first transistor M1. When the first transistor M1 is turned on, a voltage corresponding to the data signal supplied to the data line Dm 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 and the first transistor M1 is turned off.

After the first transistor M1 is turned off, the supply of the first control signal and the second control signal is stopped. When the supply of the first control signal and the second control signal is stopped, the fourth transistor M4 is turned on and the third transistor M3 is turned off. When the fourth transistor M4 is turned on, the voltage value of the first node N1 increases to the voltage of the voltage source Vsus. In this case, the voltage of the gate electrode of the second transistor M2 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 second transistor M2 is determined by Equation (1).

ΔV _{M2 _gate} = ΔV _N1 × (Cfb / (Cst + Cfb))

In Equation 1, ΔV _{M2 _gate} refers to the voltage change amount of the second transistor M2 gate electrode, and ΔV _N1 refers to the voltage change amount of the first node N1.

Referring to Equation 1, the amount of change in the gate electrode voltage of the second transistor M2 is changed corresponding to the amount of change in the voltage of the first node N1. That is, when the supply of the first control signal and the second control signal is stopped and the voltage of the first node N1 increases, the voltage of the gate electrode of the second transistor M2 also increases. Thereafter, the second transistor M2 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, the organic light emitting diode OLED generates predetermined light corresponding to the current.

On the other hand, the organic light emitting diode OLED deteriorates with time. Here, the voltage Voled of the organic light emitting diode OLED increases as the organic light emitting diode OLED deteriorates. When the voltage Voled 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 voltage Voled of the organic light emitting diode OLED supplied to the first node N1 increases, and accordingly, the voltage rising width of the first node N1 increases. The organic light emitting diode is set lower than when it is not degraded.

When the voltage rising width of the first node N1 is set to be low, the voltage rising width of the gate electrode of the second transistor M2 is lowered as shown in Equation (1). Then, the amount of current supplied from the second transistor M2 increases in response to the same data signal. That is, according to the present invention, as the organic light emitting diode OLED is deteriorated, the amount of current supplied from the second transistor M2 increases, thereby compensating for the decrease in luminance due to the deterioration of the organic light emitting diode OLED.

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 included. Are formed of different materials and therefore have 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. In FIG. 6, a detailed description of the same configuration as that of FIG. 4 will be omitted.

Referring to FIG. 6, the compensator 142 according to the second embodiment of the present invention may include a third transistor M3 and a fourth transistor positioned between a voltage source Vsus and an anode electrode of an organic light emitting diode OLED. M4 and a feedback capacitor Cfb positioned between the first node N1 and the gate electrode of the second transistor M2.

The third transistor M3 is positioned between the first node N1 and the anode electrode of the organic light emitting diode OLED, and is controlled by the first control signal supplied from the first control line CL1n. Here, the third transistor M3 is set as an NMOS transistor. That is, the third transistor M3 is set to a different conductivity type from the transistors M1, M2, and M4 included in the pixel 140. Accordingly, the third transistor M3 is turned on when the first control signal is supplied from the first control line CL1n and turned on when the first control signal is not supplied (low voltage).

The fourth transistor M4 is located 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 fourth transistor M4 is turned off when the first control signal is supplied, and is turned off when the first control signal is not supplied.

In the compensator 142 according to the second embodiment of the present invention, the third transistor M3 is formed of an NMOS as compared to FIG. 4, and accordingly, the second control line CL2n may be removed. In other words, the compensator 142 according to the second embodiment of the present invention is driven by the first control signal supplied to the first control line CL1n.

5, the first control signal is supplied to the first control line CL1n before the scan signal is supplied to the scan line Sn. When the first control signal is supplied, the fourth transistor M4 is turned off and the third transistor M3 is turned on. When the third transistor M3 is turned on, the voltage Voled of the organic light emitting diode OLED is supplied to the first node N1.

Thereafter, the scan signal is supplied to the scan line Sn to turn on the first transistor M1. When the first transistor M1 is turned on, a voltage corresponding to the data signal supplied to the data line Dm 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 and the first transistor M1 is turned off.

After the first transistor M1 is turned off, the supply of the first control signal to the first control line CL1n is stopped. When the supply of the first control signal is stopped, the fourth transistor M4 is turned on and the third transistor M3 is turned off. When the fourth transistor M4 is turned on, the voltage of the first node N1 increases to the voltage of the voltage source Vsus, and accordingly, the voltage of the gate electrode of the second transistor M2 also increases. In this case, since the gate electrode voltage rising width of the second transistor M2 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.

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 will be omitted from FIG. 7.

Referring to FIG. 7, the compensator 142 according to the third embodiment of the present invention may include a third transistor M3 and a fourth transistor positioned between a voltage source Vsus and an anode electrode of an organic light emitting diode OLED. M4 and a feedback capacitor Cfb positioned between the first node N1 and the gate electrode of the second transistor M2.

The third transistor M3 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.

The fourth transistor M4 is located 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.

The compensator 142 according to the third embodiment of the present invention can remove the second control line CL2n as compared with FIG. 7. In other words, the third transistor M3 is connected to the scan line Sn, whereby the second control line CL2n can be removed.

Referring to FIG. 5, the first control signal (high signal) is supplied to the first control line CL1n before the scan signal is supplied to the scan line Sn. When the first control signal is supplied, the fourth transistor M4 is turned off.

Thereafter, the scan signal is supplied to the scan line Sn to turn on the first transistor M1 and the third transistor M3. When the first transistor M1 is turned on, a voltage corresponding to the data signal supplied to the data line Dm is charged in the storage capacitor Cst. When the third transistor M3 is turned on, the voltage Voled of the organic light emitting diode OLED is supplied to the first node N1. After the voltage corresponding to the data signal is charged to the storage capacitor Cst and the voltage of the organic light emitting diode OLED is supplied to the first node N1, the supply of the scan signal is stopped, thereby the first transistor M1 and The third transistor M3 is turned off.

After the first transistor M1 and the third transistor M3 are turned off, the supply of the first control signal to the first control line CL1n is stopped. When the supply of the first control signal is stopped, the fourth transistor M4 is turned on so that the voltage of the first node N1 increases to the voltage of the voltage source Vsus. When the voltage of the first node N1 rises to the voltage of the voltage source Vsus, the voltage of the gate electrode of the second transistor M2 also rises as shown in Equation (1). Here, since the gate electrode voltage rising width of the second transistor M2 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.

FIG. 8 is a diagram illustrating a fourth embodiment of the compensator shown in FIG. 3. In FIG. 8, detailed description of the same configuration as that of FIG. 4 will be omitted.

Referring to FIG. 8, the compensator 142 according to the fourth embodiment of the present invention may include a third transistor M3 and a fourth transistor positioned between a voltage source Vsus and an anode electrode of an organic light emitting diode OLED. M4 and a feedback capacitor Cfb positioned between the first node N1 and the gate electrode of the second transistor M2.

The third transistor M3 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.

The fourth transistor M4 is positioned between the first node N1 and the voltage source Vsus, and is controlled by the scan signal supplied from the scan line Sn. Here, the fourth transistor M4 is formed of NMOS. Therefore, the fourth transistor M4 is turned off when the scan signal is supplied to the scan line Sn and is turned on when the scan signal is not supplied.

The compensator 142 according to the fourth embodiment of the present invention can remove the first control line CL1n and the second control line CL2n as compared with FIG. 4. In other words, the third transistor M3 and the fourth transistor M4 are connected to the scan line Sn, thereby removing the first control line CL1n and the second control line CL2n.

Referring to the operation, first, when the scan signal is supplied to the scan line Sn, the first transistor M1 and the third transistor M3 are turned on. The fourth transistor M4 is turned off by the scan signal supplied to the scan line Sn.

When the first transistor M1 is turned on, a voltage corresponding to the data signal supplied to the data line Dm is charged in the storage capacitor Cst. When the third transistor M3 is turned on, the voltage Voled of the organic light emitting diode OLED is supplied to the first node N1. After the voltage corresponding to the data signal is charged to the storage capacitor Cst and the voltage of the organic light emitting diode OLED is supplied to the first node N1, the supply of the scan signal is stopped, thereby the first transistor M1 and The third transistor M3 is turned off.

When the supply of the scan signal to the scan line Sn is stopped, the fourth transistor M4 is turned on. When the fourth transistor M4 is turned on, the voltage of the first node N1 increases to the voltage of the voltage source Vsus. When the voltage of the first node N1 rises to the voltage of the voltage source Vsus, the gate electrode voltage of the second transistor M2 also rises as shown in Equation (1). Here, since the gate electrode voltage rising width of the second transistor M2 is determined to correspond to the degradation of the organic light emitting diode OLED, the degradation of the organic light emitting diode OLED may be compensated for.

4 to 8 illustrate that the fourth transistor M4 is connected to the voltage source Vsus, the present invention is not limited thereto. Indeed, in the present invention, the fourth transistor M4 can be connected to various voltage sources.

9 is a view showing a compensator according to a fifth embodiment of the present invention. Detailed description of the same parts as in FIG. 4 in FIG. 9 will be omitted.

Referring to FIG. 9, in the compensator 142 according to the fifth embodiment of the present invention, the fourth transistor M4 is connected to the first power source ELVDD. When the fourth transistor M4 is connected to the first power supply ELVDD, the voltage of the first node N1 is increased from the voltage Voled of the organic light emitting diode OLED to the voltage of the first power supply ELVDD. At this time, the gate electrode voltage of the second transistor M2 is increased by the equation (1). That is, even if the fourth transistor M4 is connected to the first power source ELVDD, the object and effect of the present invention, which can compensate for deterioration of the organic light emitting diode OLED, can be stably achieved.

Meanwhile, although FIG. 9 has been described using the structure of the compensator 142 shown in FIG. 4, the present invention is not limited thereto. In fact, the fourth transistor M4 may be connected to the first power source ELVDD in the pixels of FIGS. 5 to 8.

10 is a view showing a compensation unit according to a sixth embodiment of the present invention. Detailed description of the same parts as in FIG. 4 in FIG. 10 will be omitted.

Referring to FIG. 10, in the compensator 142 according to the sixth embodiment of the present invention, the fourth transistor M4 is connected to the scan line Sn. Here, as shown in FIG. 5, when the fourth transistor M4 is turned on, a voltage corresponding to the turn-off is supplied to the scan line Sn. Therefore, the voltage of the first node N1 rises from the voltage Voled of the organic light emitting diode OLED to the turn-off voltage supplied to the scan line Sn. That is, even when the fourth transistor M4 is connected to the scan line Sn, deterioration of the organic light emitting diode OLED can be compensated for stably. In addition, as illustrated in FIG. 11, the fourth transistor M4 may be connected to the previous scan line Sn-1.

10 and 11 have been described using the structure of the compensator 142 shown in FIG. 4, but the present invention is not limited thereto. In fact, in the pixels of FIGS. 5 to 8, the fourth transistor M4 may be connected to the scan line Sn.

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, according to the pixel, the organic light emitting display device using the same, and a driving method thereof, the organic light emitting diode is deteriorated by controlling the gate electrode voltage of the driving transistor in response to the organic light emitting diode. You can compensate. In addition, deterioration due to lifetime characteristics of the red organic light emitting diode, the green organic light emitting diode, and the blue organic light emitting diode may be compensated by adjusting the capacitance of the feedback capacitor included in each of the red pixel, the green pixel, and the blue pixel.

Claims (53)

An organic light emitting diode; A first transistor connected to the scan line and the data line and turned on when the scan signal is supplied to the scan line; A storage capacitor for charging a voltage corresponding to the data signal supplied to the data line; A second transistor for supplying a current corresponding to the voltage charged in the storage capacitor from a first power supply to a second power supply via the organic light emitting diode; And a compensation unit connected to a voltage source having a voltage value higher than the voltage applied to the anode electrode of the organic light emitting diode and controlling the voltage of the gate electrode of the second transistor in response to deterioration of the organic light emitting diode. Pixel made. The method of claim 1, The compensation unit A third transistor and a fourth transistor positioned between the voltage source and the anode electrode of the organic light emitting diode; And a feedback capacitor connected between the common node of the third and fourth transistors and the gate electrode of the second transistor. The method of claim 2, The fourth transistor is turned off when the first control signal is supplied from the first control line, otherwise it is turned on. And the third transistor is turned on when the second control signal is supplied from the second control line, and is turned off in other cases. The method of claim 3, wherein And the first control signal and the second control signal are superimposed on the scan signal supplied to the scan line and set to voltages of opposite polarities. The method of claim 3, wherein The voltage applied to the anode electrode of the organic light emitting diode is supplied to the common node when the third transistor is turned on, and the voltage of the common node rises to the voltage of the voltage source when the fourth transistor is turned on. Pixels characterized in that. The method of claim 5, And the feedback capacitor controls the gate electrode voltage of the second transistor in response to the voltage change amount of the common node. The method of claim 2, The third transistor and the fourth transistor are formed of different conductivity types, and the fourth transistor is turned off when the first control signal is supplied from the first control line, and the third transistor is turned off from the first control line. And turn on when the first control signal is supplied. The method of claim 7, wherein And the first control signal is supplied to overlap the scan signal supplied to the scan line. The method of claim 7, wherein Wherein the third transistor is formed of NMOS, and the first transistor, the second transistor, and the fourth transistor are formed of PMOS. The method of claim 7, wherein The voltage applied to the anode electrode of the organic light emitting diode is supplied to the common node when the third transistor is turned on, and the voltage of the common node rises to the voltage of the voltage source when the fourth transistor is turned on. Pixel characterized in that. The method of claim 10, And the feedback capacitor controls the gate electrode voltage of the second transistor in response to the voltage change amount of the common node. The method of claim 2, The third transistor is turned on when the scan signal is supplied to the scan line, and the fourth transistor is turned off when the first control signal is supplied to the first control line and turned on in other cases. Pixel characterized. The method of claim 12, And the first control signal is supplied to overlap with the scan signal. The method of claim 12, The voltage applied to the anode electrode of the organic light emitting diode is supplied to the common node when the third transistor is turned on, and the voltage of the common node rises to the voltage of the voltage source when the fourth transistor is turned on. Pixels characterized in that. The method of claim 14, And the feedback capacitor controls the gate electrode voltage of the second transistor in response to the voltage change amount of the common node. The method of claim 2, The third transistor and the fourth transistor are formed of different conductivity types, the third transistor is turned on when a scan signal is supplied to the scan line, and the fourth transistor is turned off when the scan signal is supplied. Pixels, characterized in that. The method of claim 16, The voltage applied to the anode electrode of the organic light emitting diode is supplied to the common node when the third transistor is turned on, and the voltage of the common node is turned on when the fourth transistor is turned on because the supply of the scan signal is stopped. And the voltage rises to the voltage of the voltage source. The method of claim 17, And the feedback capacitor controls the gate electrode voltage of the second transistor in response to the voltage change amount of the common node. delete The method of claim 2, And the voltage of the voltage source is set below the voltage of the first power supply. The method of claim 2, And the voltage source is the first power supply. The method of claim 2, And the voltage source is a turn-off voltage supplied to the scan line or a previous scan line positioned before the scan line. The method of claim 2, 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. Each pixel is set differently from each other. An organic light emitting diode; A first transistor connected to the scan line and the data line and turned on when the scan signal is supplied to the scan line; A storage capacitor for charging a voltage corresponding to the data signal supplied to the data line; A second transistor for supplying a current corresponding to the voltage charged in the storage capacitor from a first power supply to a second power supply via the organic light emitting diode; A third transistor and a fourth transistor positioned between the anode electrode of the organic light emitting diode and a voltage source having a voltage value higher than the voltage applied to the anode electrode of the organic light emitting diode; And a feedback capacitor positioned between the common node of the third and fourth transistors and the gate electrode of the second transistor. The method of claim 24, The voltage applied to the anode electrode of the organic light emitting diode is supplied to the common node when the third transistor is turned on, and the voltage of the common node rises to the voltage of the voltage source when the fourth transistor is turned on. Pixels characterized in that. The method of claim 25, And the feedback capacitor controls the gate electrode voltage of the second transistor in response to the voltage change amount of the common node. The method of claim 25, The fourth transistor is turned off when the first control signal is supplied from the first control line, otherwise it is turned on. And the third transistor is turned on when the second control signal is supplied from the second control line, and is turned off in other cases. The method of claim 27, And the first control signal and the second control signal are superimposed on the scan signal supplied to the scan line and set to voltages of opposite polarities. The method of claim 25, The third transistor and the fourth transistor are formed of different conductivity types, and the fourth transistor is turned off when the first control signal is supplied from the first control line and the third transistor is turned off from the first control line. And turn on when the first control signal is supplied. The method of claim 29, And the first control signal is supplied to overlap the scan signal supplied to the scan line. The method of claim 25, The third transistor is turned on when the scan signal is supplied to the scan line, and the fourth transistor is turned off when the first control signal is supplied to the first control line and turned on in other cases. Pixel characterized. The method of claim 31, wherein And the first control signal is supplied to overlap with the scan signal. The method of claim 25, The third transistor and the fourth transistor are formed of different conductivity types, the third transistor is turned on when a scan signal is supplied to the scan line, and the fourth transistor is turned off when the scan signal is supplied. Pixels, characterized in that. The method of claim 24, And the voltage source is the first power supply. The method of claim 24, And the voltage source is a turn-off voltage supplied to the scan line or a previous scan line positioned before the scan line. The method of claim 24, 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. Each pixel is set differently from each other. Pixels positioned to be connected to the scan lines and the data lines; A scan driver for sequentially supplying scan signals to the scan lines; A data driver for driving the data lines; Each of the pixels An organic light emitting diode; A first transistor connected to the scan line and the data line and turned on when the scan signal is supplied to the scan line; A storage capacitor for charging a voltage corresponding to the data signal supplied to the data line; A second transistor for supplying a current corresponding to the voltage charged in the storage capacitor from a first power supply to a second power supply via the organic light emitting diode; A third transistor and a fourth transistor positioned between the anode electrode of the organic light emitting diode and a voltage source having a voltage value higher than the voltage applied to the anode electrode of the organic light emitting diode; And a feedback capacitor positioned between the common node of the third and fourth transistors and the gate electrode of the second transistor. The method of claim 37, wherein The voltage applied to the anode electrode of the organic light emitting diode is supplied to the common node when the third transistor is turned on, and the voltage of the common node rises to the voltage of the voltage source when the fourth transistor is turned on. An organic light emitting display device, characterized in that. The method of claim 38, And the feedback capacitor controls the gate electrode voltage of the second transistor in response to the voltage change amount of the common node. The method of claim 38, The fourth transistor is turned off when the first control signal is supplied from the first control line, otherwise it is turned on. And the third transistor is turned on when the second control signal is supplied from the second control line, and is turned off in other cases. The method of claim 40, And the first control signal and the second control signal are superimposed with a scan signal supplied to the scan line and set to voltages of opposite polarities. The method of claim 38, The third transistor and the fourth transistor are formed of different conductivity types, and the fourth transistor is turned off when the first control signal is supplied from the first control line, and the third transistor is turned off from the first control line. And turn on when the first control signal is supplied. The method of claim 42, wherein And the first control signal is superimposed on a scan signal supplied to the scan line. The method of claim 38, The third transistor is turned on when the scan signal is supplied to the scan line, and the fourth transistor is turned off when the first control signal is supplied to the first control line and turned on in other cases. An organic light emitting display device. The method of claim 44, And the first control signal is supplied to overlap the scan signal. The method of claim 38, The third transistor and the fourth transistor are formed of different conductivity types, the third transistor is turned on when a scan signal is supplied to the scan line, and the fourth transistor is turned off when the scan signal is supplied. An organic light emitting display device, characterized in that. The method of claim 37, wherein And the voltage source is the first power source. The method of claim 37, wherein And the voltage source is a turn-off voltage supplied to the scan line or a previous scan line positioned before the scan line. The method of claim 37, 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. Charging a voltage corresponding to the data signal to a storage capacitor connected to the gate electrode of the driving transistor when the scan signal is supplied; Maintaining one terminal of the feedback capacitor connected to the gate electrode of the driving transistor at a voltage applied to the anode electrode of the organic light emitting diode while the storage capacitor is charged with a voltage corresponding to the data signal; , And increasing the voltage of the other terminal of the feedback capacitor to the voltage of the voltage source after the supply of the scan signal is stopped. 51. The method of claim 50, 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 51, The voltage of the voltage source is set to a voltage value higher than the voltage applied to the anode electrode of the organic light emitting diode. The method of claim 51, And a voltage of the voltage source is set to a voltage value less than or equal to the first power supply.

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