KR20060112979A - Pixel and light emitting display using the same - Google Patents

Abstract

A pixel and a light emitting display using the same are provided to display uniform images by charging a storage capacitor with voltage corresponding to threshold voltage of a first transistor controlling the amount of current flowing to a light emitting element and a data signal. A pixel(140) comprises a light emitting element(OLED); a second transistor(M2) connected with an n-th scan line(Sn) and a data line(Dm) and turned on when a scan signal is supplied to the n-th scan line; a first transistor(M1) having a first electrode connected to a second electrode of the second transistor and a gate electrode connected to a storage capacitor(C); a third transistor(M3) connected between the second electrode and the gate electrode of the first transistor and turned on when the scan signal is supplied to the n-th scan line; a fourth transistor(M4) connected between a second power source(ELVDD2) and the storage capacitor and turned on when an emission control signal is supplied to an emission control line(En); a fifth transistor(M5) connected to a common terminal of the storage capacitor and the fourth transistor and turned on when the emission control signal is not supplied; a sixth transistor(M6) connected between an initializing power source(Vint) and the gate electrode of the first transistor and turned on when the scan signal is supplied to an (n-1)th scan line(Sn-1); a seventh transistor(M7) connected between a first power source(ELVDD1) and the first electrode of the first transistor and turned on when the emission control signal is not supplied; and an eighth transistor(M8) connected between the light emitting element and the second electrode of the first transistor and turned on when the emission control signal is not supplied.

Description

Pixel and Light Emitting Display Using the same

1 is a circuit diagram showing a pixel of the prior art.

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

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

4 is a waveform diagram illustrating a driving waveform supplied to the pixel illustrated in FIG. 3.

5 is a graph illustrating a pixel current corresponding to the voltage drop of the first power supply.

6 is a circuit diagram illustrating another example of the pixel illustrated in FIG. 2.

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

142,146 Pixel circuit 140,144 Pixel

110: scan driver 120: data driver

130: pixel portion 150: timing controller

The present invention relates to a pixel and a light emitting display device using the same, and more particularly, to a pixel and a light emitting display device using the same to display a uniform image.

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, a light emitting display, and the like.

Among the flat panel display devices, the light emitting display device displays an image by using light emitting devices that generate light by recombination of electrons and holes. Such a light emitting display device has an advantage in that it has a fast response speed and is driven with low power consumption.

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

Referring to FIG. 1, a pixel 4 of a conventional light emitting display device is connected to a light emitting device OLED, a data line Dm, and a scanning line Sn to control a light emitting device OLED 2. ).

The anode electrode of the light emitting element OLED is connected to the pixel circuit 2, and the cathode electrode is connected to the second power source ELVSS. The light emitting device OLED generates light having a predetermined luminance in response to a current supplied from the pixel circuit 2.

The pixel circuit 2 controls the amount of current supplied to the light emitting element 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 light emitting device OLED, the second transistor M2, the data line Dm, and the scan line Sn. And a storage capacitor C connected between the first electrode M1 and the gate electrode of the second transistor M2 and the first electrode.

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 C. 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 the scan signal is supplied to the scan line Sn to receive the data signal supplied from the data line Dm to the storage capacitor C. ). In this case, the storage capacitor C 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 C, and the first electrode is connected to the other terminal of the storage capacitor C and the first power supply ELVDD. The second electrode of the second transistor M2 is connected to the anode electrode of the light emitting element OLED. The second transistor M2 controls the amount of current flowing from the first power supply ELVDD to the light emitting device OLED in response to the voltage value stored in the storage capacitor C. In this case, the light emitting device OLED generates light corresponding to the amount of current supplied from the second transistor M2.

However, there is a problem in that the pixel 4 of the conventional light emitting display device cannot display an image of uniform luminance. In detail, the threshold voltage of the second transistor M2 included in each of the pixels 4 is set differently for each pixel 4 due to a process deviation or the like. As such, when the threshold voltages of the second transistor M2 are set differently for each of the pixels 4, the amount of current supplied to the light emitting device OLED becomes different even when the data signals having the same gray level are supplied to the pixels 4. As a result, an uneven image is displayed.

In the conventional pixel 4, the storage capacitor C charges a voltage corresponding to the difference voltage between the first power supply ELVDD and the data signal. Therefore, the voltage of the first power supply ELVDD must be kept constant at all times in order to charge the storage capacitor C with a desired voltage. However, in the related art, since a predetermined current is supplied to the plurality of pixels from the first power supply ELVDD, a voltage drop occurs in the first power supply ELVDD, and thus, the capacitor C cannot be charged with a desired voltage. Is generated. In particular, since the voltage drop voltage of the first power supply ELVDD is set differently according to the positions of the pixels 4, an image of uniform luminance cannot be displayed.

Accordingly, an object of the present invention is to provide a pixel and a light emitting display device using the same to display a uniform image.

In order to achieve the above object, the first aspect of the present invention and the light emitting device; A second transistor connected to an nth (n is a natural number) scan line and a data line and turned on when a scan signal is supplied to the nth scan line; A first transistor having a first electrode connected to a second electrode of the second transistor and a gate electrode connected to a storage capacitor; A third transistor connected between the second electrode and the gate electrode of the first transistor and turned on when a scan signal is supplied to the nth scan line; A fourth transistor connected between a second power supply and the storage capacitor and turned on when an emission control signal is supplied to an emission control line; A fifth transistor connected to a common terminal of the fourth transistor and the storage capacitor and turned on when the emission control signal is not supplied; A sixth transistor connected between an initialization power supply and a gate electrode of the first transistor and turned on when a scan signal is supplied to the n-th scan line; A seventh transistor connected between a first power supply and a first electrode of the first transistor and turned on when the emission control signal is not supplied; A pixel including an eighth transistor connected between the light emitting device and the second electrode of the first transistor and turned on when the emission control signal is not supplied is provided.

Preferably, when the scan signal is supplied to the nth scan line, the storage capacitor is charged with a voltage corresponding to the difference between the voltage value obtained by subtracting the threshold voltage of the first transistor from the data signal supplied to the data line and the second power source. do. The first transistor controls the amount of current flowing from the first power source to the light emitting device in response to the voltage charged in the storage capacitor.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 2 to 6 that can be easily implemented by those skilled in the art.

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

Referring to FIG. 2, a light emitting display device according to an exemplary embodiment may include at least one scan line S1 to Sn, data lines D1 to Dm, a first power line VL1, and a second power line VL2. The pixel unit 130 including the pixels 140 connected to the first and second pixels, the scan driver 110 for driving the scan lines S1 to Sn, and the data driver for driving the data lines D1 to Dm. 120 and a timing controller 150 for controlling the scan driver 110 and the data driver 120.

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 scan driver 110 receives the scan driving control signal SCS from the timing controller 150. The scan driver 110 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 110 generates an emission control signal in response to the scan driving control signal SCS, and sequentially supplies the generated emission control signal to the emission control lines E1 to En. Here, the width of the light emission control signal is set equal to or wider than the width of the scan signal. For example, the light emission control signal may be supplied to overlap two scan signals.

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 pixels 140 are connected to the data line D, the scan line S, the first power line VL1, and the second power line VL2. The first power line VL1 and the second power line VL2 are formed in parallel with the data line D. FIG. Here, the first power supply line VL1 is connected to the first power supply ELVDD1, and the second power supply line VL2 is connected to the second power supply ELVDD2. The pixels 140 connected to the data line D, the scan line S, the first power line VL1, and the second power line VL2 are selected when a scan signal is supplied to the second power line ELVDD2. The voltage corresponding to the difference between the signals is charged, and a current corresponding to the charged voltage is supplied from the first power supply ELVDD1 to the light emitting device to generate predetermined light. To this end, the voltage values of the first power supply ELVDD1 and the second power supply ELVDD2 are set higher than the voltage value of the data signal. The voltage values of the first power supply ELVDD1 and the second power supply ELVDD2 are set to be the same or different.

3 is a circuit diagram illustrating an embodiment of a pixel illustrated in FIG. 2. In FIG. 3, a pixel connected to the m-th data line Dm, an n-th scan line Sn, and an n-th emission control line En is shown for convenience of description.

Referring to FIG. 3, the pixel 140 of the present invention includes the light emitting device OLED, the data line Dm, the scan lines Sn-1 and Sn, the light emission control line En, and the first power line VL1. And a pixel circuit 142 connected to the second power line VL2 to emit light from the light emitting device OLED. Here, the pixel circuit 142 is connected to the initialization power supply Vint supplied from the outside by tracking.

The anode electrode of the light emitting element OLED is connected to the pixel circuit 142, and the cathode electrode is connected to the third power source ELVSS. The light emitting device OLED generates light having a predetermined luminance in response to a current supplied from the pixel circuit 142. To this end, the light emitting device OLED is formed of an organic material including fluorescent and / or phosphorescent. Meanwhile, the voltage value of the third power supply ELVSS is set lower than the voltage values of the first power supply ELVDD1 and the second power supply ELVDD2.

The pixel circuit 142 is selected when a scan signal is supplied to the scan line Sn and receives a data signal supplied to the data line Dm. The pixel circuit 142 receiving the data signal charges the storage capacitor C with a voltage corresponding to the data signal and the threshold voltage of the first transistor M1, and supplies a current corresponding to the charged voltage to the light emitting device OLED. To supply. That is, in the present invention, since the voltage corresponding to the threshold voltage of the first transistor M1 as well as the voltage corresponding to the data signal is additionally charged, the storage capacitor C can display a uniform image.

The pixel circuit 142 includes first to eighth transistors M1 to M8 and a storage capacitor C.

The first electrode of the second transistor M2 is connected to the data line Dm, and the second electrode is connected to the first node N1. The gate electrode of the second transistor M2 is connected to the nth scan line Sn. The second transistor M2 is turned on when the scan signal is supplied to the nth scan line Sn to supply the data signal supplied to the data line Dm to the first node N1.

The first electrode of the first transistor M1 is connected to the first node N1, and the second electrode is connected to the first electrode of the eighth transistor M8. The gate electrode of the first transistor M1 is connected to the second node N2. The first transistor M1 controls the amount of current supplied from the first power source ELVDD1 to the light emitting device OLED in response to the voltage charged in the storage capacitor C. FIG.

The first electrode of the third transistor M3 is connected to the second electrode of the first transistor M1, and the second electrode is connected to the second node N2. The gate electrode of the third transistor M3 is connected to the nth scan line Sn. The third transistor M3 is turned on when the scan signal is supplied to the nth scan line Sn to connect the first transistor M1 in the form of a diode.

The first electrode of the fourth transistor M4 is connected to the second power supply line VL2, and the second electrode is connected to the third node N3. The gate electrode of the fourth transistor M4 is connected to the emission control signal En. The fourth transistor M4 is turned on when the emission control signal is supplied to electrically connect the second power line VL2 and the third node N3. On the other hand, the fourth transistor M4 is formed to have a different conductivity type from the other transistors M5, M7, and M8 connected to the emission control line En to be turned on when the emission control signal is supplied. For example, when the other transistors M5, M7, and M8 are formed in the PMOS type, the fourth transistor M4 is formed in the NMOS type.

The first electrode of the fifth transistor M5 is connected to the first node N1, and the second electrode is connected to the third node N3. The gate electrode of the fifth transistor M5 is connected to the emission control line En. The fifth transistor M5 is turned off when the emission control signal is supplied, and is turned on in other cases.

The first electrode of the sixth transistor M6 is connected to the initialization power supply Vint, and the second electrode is connected to the second node N2. The gate electrode of the sixth transistor M6 is connected to the n-1 th scan line Sn-1. The sixth transistor M6 is turned on when the scan signal is supplied to the n-th scan line Sn- 1 to supply the voltage of the initialization power supply Vint to the second node N2.

The first electrode of the seventh transistor M7 is connected to the first power supply line VL1, and the second electrode is connected to the first node N1. The gate electrode of the seventh transistor M7 is connected to the emission control line En. The seventh transistor M7 is turned off when the emission control signal is supplied, and is otherwise turned on.

The first electrode of the eighth transistor M8 is connected to the second electrode of the first transistor M1, and the second electrode is connected to the anode electrode of the light emitting element OLED. The gate electrode of the eighth transistor M8 is connected to the emission control line En. The eighth transistor M8 is turned off when the emission control signal is supplied, and is turned on in other cases.

4 is a diagram illustrating a driving waveform supplied to the pixel illustrated in FIG. 3. The operation of the pixel 140 will be described in detail with reference to FIGS. 3 and 4. First, the scan signal is supplied to the n-th scan line Sn- 1 so that the sixth transistor M6 is turned on. When the sixth transistor M6 is turned on, the initialization power supply Vint and the second node N2 are electrically connected to each other. Then, the voltage of the gate electrode of the first transistor M1 connected to the second node N2 and one terminal of the storage capacitor C is changed to the voltage of the initialization power supply Vint. Here, the voltage value of the initialization power supply Vint is set to a voltage value lower than that of the data signal.

Thereafter, the supply of the scan signal to the n-th scan line Sn-1 is stopped, and the scan signal is supplied to the n-th scan line Sn. The emission control signal is supplied to the nth emission control line En during the period in which the scan signals are supplied to the n-1th scan line Sn-1 and the nth scan line Sn.

When the scan signal is supplied to the nth scan line Sn, the second transistor M2 and the third transistor M3 are turned on. When the emission control signal is supplied to the nth emission control line En, the fourth transistor M4 is turned on, and the fifth transistor M5, the seventh transistor M7, and the eighth transistor M8 are turned on. Is off.

When the third transistor M3 is turned on, the second electrode and the gate electrode of the first transistor M1 are electrically connected to each other. That is, when the third transistor M3 is turned on, the first transistor M1 is connected in the form of a diode. When the second transistor M2 is turned on, the data signal supplied to the data line Dm is transmitted to the first transistor M1 via the second transistor M2, the first transistor M1, and the third transistor M3. Is supplied to the gate electrode (ie, the second node N2). In this case, the voltage value of the second node N2 is determined as a value obtained by subtracting the threshold voltage of the first transistor M1 from the voltage value of the data signal.

When the fourth transistor M4 is turned on, the voltage of the second power source ELVDD2 is applied to the third node N3. At this time, the storage capacitor C is charged with a voltage corresponding to the voltage difference between the third node N3 and the second node N2. That is, the storage capacitor C is charged with a voltage corresponding to the data signal and the threshold voltage of the first transistor M1. Therefore, the pixel unit 130 displays a uniform image regardless of the threshold voltage of the first transistor M1 included in each of the pixels 140.

In the present invention, since the storage capacitor C is charged with a predetermined voltage using the second power supply ELVDD2 without voltage drop, an image having a desired luminance can be displayed. In detail, the first transistor M1 controls the amount of current flowing from the first power source ELVDD1 to the light emitting device OLED. Accordingly, a predetermined current is supplied from the first power supply ELVDD1 to the pixels 140, and thus a predetermined voltage drop is generated in the first power supply ELVDD1. On the other hand, no current is supplied from the second power source ELVDD2 to the pixel 140. As such, when no current is supplied from the second power supply ELVDD2 to the pixel 140, the voltage drop of the second power supply ELVDD2 does not occur. In other words, the second power supply ELVDD2 always maintains a constant voltage, and thus the storage capacitor C is charged with the correct voltage corresponding to the data signal.

After the predetermined voltage is charged in the storage capacitor C, the supply of the emission control signal is stopped to turn on the fifth transistor M5, the seventh transistor M7, and the eighth transistor M8, and the fourth transistor is turned on. M4 is turned off. When the eighth transistor M8 is turned on, the second electrode of the first transistor M1 and the light emitting device OLED are electrically connected to each other. When the seventh transistor M7 is turned on, the first power source ELVDD1 and the first node N1 are electrically connected to each other. When the fifth transistor M5 is turned on, the first node N1 and the third node N3 are electrically connected to each other. At this time, the voltage value of the third node N3 is increased to the voltage of the first power source ELVDD1. In this case, the voltage of the second node N2 connected to the third node N3 by the storage capacitor C also changes in correspondence with the voltage variation of the third node N3. As such, when the voltage of the second node N2 changes in response to the voltage variation of the third node N3, the voltage charged in the storage capacitor C does not change even when the fifth transistor M5 is turned on. Is maintained.

Meanwhile, when the fifth transistor M5, the seventh transistor M7, and the eighth transistor M8 are turned on, a current path is formed from the first power source ELVDD1 to the light emitting device OLED. In this case, the first transistor M1 supplies a current corresponding to the voltage charged in the storage capacitor C from the first power supply ELVDD1 to the light emitting device OLED.

5 is a diagram illustrating a current supplied to a light emitting device in response to a voltage drop of the first power supply. In FIG. 5, the "X" axis represents the voltage drop of the first power supply, and the "Y" axis represents the current (pixel current) supplied to the light emitting element.

Referring to FIG. 5, in the conventional pixel illustrated in FIG. 1, the pixel current changes rapidly due to the voltage drop of the first power supply ELVDD. In fact, in the conventional pixel, when a voltage drop of about 1 V occurs in the first power supply ELVDD, a pixel current variation of about 350 nA occurs. As described above, when the pixel current changes abruptly in response to the voltage drop of the first power supply ELVDD, the image of the desired luminance cannot be displayed in the pixel unit. Since the voltage drop voltage of the first power source ELVDD is different depending on the position of the pixel, an uneven image is displayed in the pixel portion.

On the other hand, in the pixel of the present invention shown in Fig. 3, the pixel current is kept substantially constant regardless of the voltage drop of the first power source ELVDD1. In fact, the pixel current of the present invention is maintained substantially constant even though a voltage drop of approximately 1V occurs in the first power supply ELVDD1. As such, when the pixel current is stably maintained regardless of the voltage drop of the first power supply ELVDD1, a desired image may be displayed in the pixel unit. When the pixel current is stably maintained regardless of the voltage drop of the first power supply ELVDD1, a uniform image is displayed in the pixel portion.

6 is a circuit diagram illustrating another example of the pixel illustrated in FIG. 2. 6, detailed description of the same parts as in FIG. 3 will be omitted.

Referring to FIG. 6, in the pixel circuit 146 of the pixel 144 according to another exemplary embodiment, the fifth transistor M5 is connected between the first power line VL1 and the third node N3. . In other words, the first electrode of the fifth transistor M5 is connected to the first power supply line VL1, and the second electrode is connected to the third node N3. The gate electrode of the fifth transistor M5 is connected to the emission control line En. The fifth transistor M5 is turned off when the emission control signal is supplied, and is turned on in other cases.

4 and 6, an operation process is described in detail. First, a scan signal is supplied to the n−1 th scan line Sn−1 to turn on the sixth transistor M6. When the sixth transistor M6 is turned on, the initialization power supply Vint and the second node N2 are electrically connected to each other. Then, the voltage of the gate electrode of the first transistor M1 connected to the second node N2 and one terminal of the storage capacitor C is changed to the voltage of the initialization power supply Vint.

Thereafter, the second transistor M2 and the third transistor M3 are turned on by the scan signal supplied to the nth scan line Sn. In addition, the fourth transistor M4 is formed by the emission control signal supplied to the nth emission control line En so as to overlap the scan signals supplied to the n-1th scan line Sn-1 and the nth scan line Sn. The fifth transistor M5, the seventh transistor M7, and the eighth transistor M8 are turned off.

When the second transistor M2 is turned on, the data signal supplied to the data line Dm is transmitted to the second node N2 via the second transistor M2, the first transistor M1, and the third transistor M3. Is supplied. At this time, the voltage value of the second node N2 is determined as a value obtained by subtracting the threshold voltage of the first transistor M1 from the voltage value of the data signal. When the fourth transistor M4 is turned on, the voltage of the second power source ELVDD2 is applied to the third node N3. Then, the storage capacitor C is charged with a voltage corresponding to the voltage difference between the third node N3 and the second node N2.

That is, the storage capacitor C is charged with a voltage corresponding to the data signal and the threshold voltage of the first transistor M1. Here, since the voltage corresponding to the threshold voltage is charged in the storage capacitor C, a uniform image can be displayed without the influence of the threshold voltage. In other words, even if the threshold voltages of the first transistor M1 are different for each pixel 144, the pixel unit 130 may display a uniform image.

In the present invention, since the storage capacitor C is charged with a predetermined voltage using the second power supply ELVDD2 without voltage drop, an image having a desired luminance can be displayed. In detail, the first transistor M1 controls the amount of current flowing from the first power source ELVDD1 to the light emitting device OLED. Accordingly, no current flows in the second power source ELVDD2, and accordingly, no voltage drop occurs in the second power source ELVDD2. In other words, the second power supply ELVDD2 may maintain a constant voltage at all times, thereby charging the storage capacitor C with a voltage corresponding to the data signal.

After the predetermined voltage is charged in the storage capacitor C, the supply of the emission control signal is stopped to turn on the fifth transistor M5, the seventh transistor M7, and the eighth transistor M8, and the fourth transistor is turned on. M4 is turned off. Then, the first transistor M1 supplies a predetermined amount of current from the first power supply ELVDD1 to the light emitting device OLED in response to the voltage charged in the storage capacitor C.

The above detailed description and drawings are merely exemplary of the present invention, which are used only for the purpose of illustrating the present invention and are not intended to limit the scope of the present invention as described above in the meaning limitation or the 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 and the light emitting display device using the same according to the embodiment of the present invention, the storage capacitor included in each pixel corresponds to the threshold voltage of the first transistor for controlling the amount of current flowing through the data signal and the light emitting element. Since the voltage is charged, a uniform image can be displayed regardless of the threshold voltage of the first transistor. In addition, in the present invention, since the voltage is charged to the storage capacitor using a separate second power source that does not generate a voltage drop in addition to the first power supply for supplying current to the light emitting device, the desired voltage may be charged to the storage capacitor. Accordingly, an image of uniform luminance can be displayed.

Claims (10)

A light emitting element; A second transistor connected to an nth (n is a natural number) scan line and a data line and turned on when a scan signal is supplied to the nth scan line; A first transistor having a first electrode connected to a second electrode of the second transistor and a gate electrode connected to a storage capacitor; A third transistor connected between the second electrode and the gate electrode of the first transistor and turned on when a scan signal is supplied to the nth scan line; A fourth transistor connected between a second power supply and the storage capacitor and turned on when an emission control signal is supplied to an emission control line; A fifth transistor connected to a common terminal of the fourth transistor and the storage capacitor and turned on when the emission control signal is not supplied; A sixth transistor connected between an initialization power supply and a gate electrode of the first transistor and turned on when a scan signal is supplied to the n-th scan line; A seventh transistor connected between a first power supply and a first electrode of the first transistor and turned on when the emission control signal is not supplied; And an eighth transistor connected between the light emitting element and the second electrode of the first transistor and turned on when the emission control signal is not supplied. The method of claim 1, When the scan signal is supplied to the nth scan line, the storage capacitor is charged with a voltage corresponding to the difference between the voltage value obtained by subtracting the threshold voltage of the first transistor from the data signal supplied to the data line and the second power source. . The method of claim 2, And the first transistor controls the amount of current flowing from the first power source to the light emitting element in response to a voltage charged in the storage capacitor. The method of claim 2, And a voltage value of the first power supply and the second power supply is set higher than the voltage value of the data signal. The method of claim 4, wherein And a voltage value of the initialization power supply is set lower than a voltage value of the data signal. The method of claim 1, And the fourth transistor is formed of a conductive type different from that of the fifth, seventh, and eighth transistors. The method of claim 1, And the fifth transistor is connected between the common terminal and the first electrode of the first transistor. The method of claim 1, And the fifth transistor is connected between the common terminal and the first power supply. A data driver for supplying a data signal to the data lines; A scan driver for supplying a scan signal to the scan lines; First power lines connected to the first power source, Second power lines connected to a second power source, A light emitting display device comprising a pixel portion including the pixels according to any one of claims 1 to 8 connected to the first power supply line, the second power supply line, the data line, and the scan line. The method of claim 9, The first power line and the second power line are formed parallel to the data line.

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