KR100570995B1 - Pixel circuit in OLED - Google Patents

Abstract

The present invention provides a pixel circuit that can reduce leakage current when the switching transistor is turned off by forming a switching transistor as a multi-gate in an organic light emitting display device capable of expressing a gray level with a high threshold voltage.

According to an exemplary embodiment of the present invention, a pixel circuit includes: a first transistor configured to transfer a data signal having a voltage level in response to a current scan line signal during data programming; A second transistor for programming a data signal having a voltage level during data programming and for generating a driving current of the EL element in response to the programmed data signal during light emission; A third transistor for providing a data signal having a voltage level to the second transistor in response to a current scan signal during data programming; A capacitor for storing the data signal of the voltage level transferred to the second transistor for maintaining the data signal of the voltage level programmed in the second transistor during data programming; A fourth transistor for transmitting a power supply voltage to the second transistor during light emission; And a fifth transistor configured to transfer a driving current provided from the second transistor according to a data signal of a voltage level during light emission. The first, third, fourth, fifth, and sixth transistors include multiple gates, and the second transistor includes: With a single gate.

Description

Pixel circuit in organic light emitting display device

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

2 is a pixel circuit diagram of an organic light emitting display device having multiple gates according to a first embodiment of the present invention;

3 is a waveform diagram illustrating an operation of a pixel circuit of an organic light emitting display device according to a first embodiment of the present invention;

4 is a circuit diagram illustrating a pixel circuit of an organic light emitting display device having multiple gates according to a second embodiment of the present invention;

5 is a plan view showing an example of a dual gate applied to a pixel circuit of the organic light emitting display device of the present invention;

6 is a plan view illustrating an example of a multiple gate applied to a pixel circuit of an organic light emitting display device according to the present invention;

7A to 7B are diagrams illustrating leakage current characteristics when a switching transistor includes a single gate thin film transistor and a dual gate thin film transistor in an organic light emitting display device;

* Description of the symbols for the main parts of the drawings *

T31, T41: driving transistor C31, C41: capacitor

T32, T35, T36, T42, T45, T46: switching transistors

T33, T34: Threshold Voltage Compensation Transistor

T34, T44: Transistor for initialization EL31, EL41: Organic light emitting element

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat panel display device. More specifically, a transistor for driving an EL element maintains an on-current characteristic by configuring a single gate, and a switching transistor is configured by using multiple gates to improve leakage current characteristics. An electroluminescent display device.

In general, the organic light emitting display device may be classified into a passive matrix OLED and an active matrix OLED according to a method of driving an EL device, and may be classified into a current driven OLED and a voltage driven OLED.

The AMOLED includes a plurality of gate lines, a plurality of data lines, a plurality of common power lines, and a plurality of pixels connected to the lines and arranged in a matrix. Each pixel typically has an EL element, two transistors, a switching transistor for transferring a data signal, a driving transistor for driving the EL element in accordance with the data signal, and one for holding the data voltage. It consists of a capacitor. The AMOLED has the advantage of low power consumption, but there is a problem in that the current intensity flowing through the EL element changes over time causing display unevenness.

This is because the voltage between the gate and the source of the driving transistor for driving the EL element, that is, the threshold voltage of the driving transistor, changes and the current flowing through the EL element changes. That is, since the threshold voltage of the driving transistor thin film transistor is changed according to manufacturing process variables, it is difficult to manufacture the transistors so that the threshold voltages of all transistors of the AMOLED are the same, and thus there is a variation in the threshold voltage between pixels. to be.

1 illustrates a pixel circuit of a conventional organic light emitting display device, and illustrates a pixel circuit of six transistors and one capacitor.

Referring to FIG. 1, a pixel circuit of a conventional organic light emitting display device includes a switching transistor T12 for transferring a data signal VDATAm provided from a data line according to a current scan signal scan [n] provided from a scanline. And a driving transistor T11 for providing a driving current corresponding to the data signal VDATAm provided through the switching transistor T12, and light corresponding to the driving current applied through the driving transistor T11. An organic light emitting element EL11 for emitting light and a capacitor C11 for storing the data signal VDATAm are provided.

In addition, the pixel circuit may be connected to the capacitor C11 according to a threshold voltage compensation transistor T13 for compensating the threshold voltage of the driving transistor T11 and a previous scan signal scan [n-1] applied to a previous scan line. An initialization transistor T14 for initializing the stored data signal, a transistor T16 for switching the supply of driving current from the driving transistor T11 to the EL element EL11 in accordance with the emission control signal em [n]; And a transistor T15 for switching the supply of the power supply voltage VDD to the driving transistor T11 according to the light emission control signal em [n].

Generally, in the pixel circuit of the organic light emitting display device, in order to effectively drive the EL element, it is preferable that the current flowing through the transistor is large when the driving voltage is applied to the gate. In other words, it is preferable that the on-state current of the driving transistor is large. On the other hand, it is preferable that the switching transistor has a small off-current. If the off-state is large, the switching transistor acts as a discharge path of the data signal stored in the capacitor C1 in the off state, and thus it is not possible to sufficiently maintain data for one frame. This is because the driving transistor cannot be turned on.

Therefore, it is preferable that the switching transistor uses a thin film transistor with a small off current, and the driving transistor preferably uses a thin film transistor with a large on current. However, in the conventional organic light emitting display device, since the switching transistor and the driving transistor are manufactured to have the same characteristics through the same manufacturing process, the on-current characteristics of the driving transistor and the off-current characteristics of the switching transistor cannot be satisfied.

Accordingly, the present invention is to solve the problems of the prior art as described above, to provide a pixel circuit of an organic light emitting display device capable of reducing the leakage current of the switching transistor while maintaining the on-current characteristics of the driving transistor. The purpose is.

In order to achieve the above object, the present invention includes a first transistor for transmitting a data signal of the voltage level in response to the current scan line signal; A second transistor for generating a driving current according to a data signal of a voltage level transmitted through the first transistor; A third transistor for detecting and self-compensating a threshold voltage deviation of the second transistor; A capacitor for storing a data signal of a voltage level transmitted to the second transistor; And an EL device that emits light in response to a driving current generated through the second transistor, wherein the first transistor and the third transistor are provided as multiple gates, and the second transistor has an organic gate having a single gate. A pixel circuit of a light emitting display device is provided.

 One of the first and third transistors includes a thin film transistor having dual gates, and the other includes a thin film transistor having multiple gates of at least two dual gates. The pixel circuit may include an initialization fourth transistor configured to discharge a data signal having a voltage level stored in the capacitor in response to a scan signal immediately before the current scan signal, and a power supply voltage in response to a current emission control signal. A fifth transistor for providing two transistors; And a sixth transistor configured to provide a driving current to the EL element through the second transistor in response to the current light emission control signal. The fourth to sixth transistors are composed of multiple gates.

The first transistor includes a PMOS transistor in which a current scan line signal is applied to a gate, a data signal of a voltage level is applied to a source, and a drain thereof is connected to the second transistor. The second transistor includes a PMOS transistor having a gate connected to one terminal of the capacitor, a source connected to the first transistor, and a drain connected to the EL element. In the third transistor, the current scan signal is applied to the gate, and the drain and the source are connected to the gate and the drain of the second transistor, respectively, and the second transistor is connected in the form of a diode in response to the current scan signal to compensate for the threshold voltage. It consists of a PMOS transistor for cycle.

In addition, the present invention includes a first transistor for transmitting a data signal of the voltage level in response to the current scan line signal during data programming; A second transistor for programming a data signal having a voltage level during data programming and generating a driving current in response to the programmed data signal during light emission; A third transistor for providing a data signal having a voltage level to the second transistor in response to a current scan signal during data programming; A capacitor for storing the data signal of the voltage level transferred to the second transistor for maintaining the data signal of the voltage level programmed in the second transistor during data programming; A fourth transistor for transmitting a power supply voltage to the second transistor during light emission; A fifth transistor configured to transfer a driving current provided from the second transistor according to a data signal having a voltage level during light emission; An initialization sixth transistor configured to discharge a data signal having a voltage level stored in the capacitor in response to a scan signal immediately before the current scan signal; And an EL device for emitting light in response to a driving current transmitted through the fifth transistor, wherein the first, third, fourth, fifth, and sixth transistors have multiple gates, and the second transistor has a single gate. A pixel circuit of an organic light emitting display device is provided.

Some of the first, third, fourth, fifth and sixth transistors include thin film transistors having dual gates, and others include thin film transistors having multiple gates of dual gates or more.

In addition, the present invention includes a first transistor to which a current scan signal is applied to a gate, and a data signal of a voltage level to a source; A second transistor having a source connected to the drain of the first transistor; A third transistor having a drain and a source connected between the gate and the drain of the second transistor, respectively; A fourth transistor having a current emission control signal applied to a gate, a power supply voltage applied to the source, and a drain connected to the source of the second transistor; A fifth transistor in which the current light emission control signal is applied to a gate, a source is connected to the drain of the second transistor, and a drain is connected to one terminal of the EL element; A sixth transistor to which a scan signal immediately before the current scan signal is applied to a gate, a source is connected to one terminal of the capacitor, and an initialization voltage is applied to the other terminal; A light emitting device having one terminal connected to the drain of the fifth transistor and the other terminal grounded; One terminal is connected to the gate of the second transistor, and the other terminal includes a capacitor to which a power supply voltage is applied, wherein the first, three, four, five and six transistors have multiple gates, the second transistor is a single gate A pixel circuit of an organic light emitting display device is provided.

In addition, the first transistor for transmitting the data signal of the voltage level in response to the current scan line signal; A second transistor for generating a driving current according to a data signal of a voltage level transmitted through the first transistor; A third transistor for detecting and self-compensating a threshold voltage deviation of the second transistor; A capacitor for storing a data signal of a voltage level transmitted to the second transistor; And an EL device for emitting light in response to a driving current generated through the second transistor, wherein the first transistor and the third transistor are provided as multiple gates, and the second transistor has a single gate. Each of the first and third transistors includes: an active layer including a plurality of body parts and a plurality of connection parts connecting one side of the body part; A pixel circuit of an organic light emitting display device includes a gate electrode arranged to intersect the active layer, and a portion of the gate electrode overlapping the active layer serves as a multiple gate.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

2 illustrates a pixel circuit of an organic light emitting display device according to a first embodiment of the present invention. The organic light emitting display device according to the first exemplary embodiment of the present invention includes a plurality of gate lines, a plurality of data lines, a plurality of power lines, and a plurality of light emission control lines, and a plurality of gate lines, data lines, power lines, and light emission. The control line includes a plurality of pixels arranged in corresponding gate lines, data lines, power lines, and light emission control lines, respectively. 2 shows one of a plurality of pixels arranged in a corresponding gate line (n-th gate line), data line (m-th data line), power line (m-th power line), and emission control line (m-th light emission control line). The circuit is limited to the pixel of FIG.

Referring to FIG. 2, a pixel circuit of an organic light emitting display device according to an exemplary embodiment of the present invention includes an organic light emitting diode EL31 that emits light corresponding to an applied driving current, and a current scan line signal applied to a corresponding scan line. a first switching transistor T32 for switching a data signal VDATAm of a voltage level applied to a corresponding data line in response to scan [n], and the first input transistor T32 which is input to a gate through the first switching transistor T32 A driving transistor T31 is provided to supply a driving current of the organic light emitting diode in accordance with the data signal.

The first switching transistor T32 is applied with a current scan signal scan [n] applied to a scan line corresponding to a gate and a data signal VDATAm of a voltage level applied to a data line corresponding to a source. The p-type thin film transistor is connected to the source of the driving transistor T31.

In the driving transistor T31, a gate is connected to one terminal of the capacitor C31, a drain is connected to an anode electrode of the EL element EL31 having a cathode electrode connected to ground, and a source is drained of the transistor T35. It is composed of a p-type thin film transistor connected to.

The pixel circuit of the present invention includes a capacitor T31 for compensating the threshold voltage of the driving transistor T31 and a capacitor C31 for storing a data signal applied to the gate of the driving transistor T31. And an initialization transistor T34 for initializing the data signal stored in the capacitor 31 in response to the previous scan signal scan [n-1] applied to the scan line immediately before the corresponding scan line.

The threshold voltage compensating transistor T33 includes a p-type thin film transistor having a drain and a source connected to gates and drains of the driving transistor T31, respectively, and a scan signal scan [n] applied to a gate. The other side of the capacitor C31 is provided with a power supply voltage VDD from a corresponding power supply line. The transistor T34 is a p-type thin film transistor in which a previous scan signal scan [n-1] is applied to a gate, a source is connected to one terminal of the capacitor C21, and an initialization voltage Vinti is applied to a drain.

In addition, the pixel circuit responds to the current light emission signal emi [n] and the second switching transistor T35 for providing the power supply voltage VDD to the driving transistor T31 and the current light emission signal emi [n]. And a third switching transistor T36 for supplying a driving current generated through the driving transistor T31 to the EL element EL31.

In the second switching transistor T35, a current emission signal emi [n] is applied to a gate, a power supply voltage is applied to a source from the corresponding power supply voltage line, and a drain is connected to a source of the driving transistor T32. It is composed of a p-type thin film transistor. In the third switching transistor T36, a current light emission signal emi [n] is applied to a gate, a source is connected to a drain of the driving transistor T31, and a drain is connected to one end of the EL element EL31. It is composed of a thin film transistor.

In the pixel circuit having the above configuration, in order to maintain excellent on-current characteristics, the driving transistor is composed of a single gate. In addition, in order to maintain a low off-current characteristic, the dual-gate comprises a threshold voltage compensation transistor T33 that directly affects the holding of the data signal of the capacitor, and a transistor T31 for switching the data signal VDATAm. do.

The operation of the pixel circuit of the present invention having the configuration as described above will be described with reference to FIG.

First, in the initialization operation, in the initialization section in which the previous scan signal scan [n-1] is low level and the current scan signal scan [n] and the emission control signal emi [n] are high level, as shown in FIG. The transistor T34 is turned on by the previous scan signal scan [n-1] and the other transistors T31-T33 and (T35-T36) by the current scan signal scan [n] and the current emission control signal emi [n]. Since is turned off, the data stored in the capacitor C31, that is, the gate voltage of the driving transistor T31 is initialized.

Next, in the data program operation, as shown in Fig. 3, a program in which the previous scan signal scan [n-1] is high level, the current scan signal scan [n] is low level, and the current light emission control signal emi [n] is high level. In the interval, the transistor T34 is turned off, the transistor T33 is turned on by the low level current scan signal scan [n], and the driving transistor T31 is connected in the form of a diode.

At this time, since the switching transistor T32 is turned on and the switching transistors T35 and T36 are turned off to form a data program pass, the data voltage VDATAm applied to the corresponding data line is the threshold voltage compensation transistor T33. Through the gate of the driving transistor T31 is provided.

Finally, at the time of light emission, as shown in FIG. 3, the previous scan signal scan [n-1] becomes high level, the current scan signal scan [n] becomes high level, and then the current emission control signal emi [n] becomes low. In the light emitting period, the switching transistors T35 and T36 are turned on, the initialization transistor T34 is turned off, and the threshold voltage compensating transistor T33 and the switching transistor T32 are turned off.

Therefore, the driving current generated corresponding to the data signal of the voltage level applied to the gate of the driving transistor T31 is provided to the organic EL element EL31 through the transistor T31 so that the organic EL element EL31 emits light. do.

As described above, in the present invention, since the deviation of the threshold voltage of the current driving transistor T31 is detected through the transistor T33 and compensates for itself, the current flowing through the organic EL element can be finely controlled. In addition, since the switching transistor T32 and the threshold voltage compensating transistor T33 are configured as dual gates, the switching transistor T32 and the threshold voltage compensation are performed by the scan signal scan [n] in the program section and the light emitting period except the initialization section. When the transistor T33 is turned off, the off current is reduced to prevent the leakage current, thereby stably maintaining the data in the capacitor C31.

4 is a block diagram illustrating a pixel circuit of an organic light emitting display device according to a second embodiment of the present invention.

Referring to FIG. 4, the pixel circuit of the organic light emitting display device according to the second embodiment is the same as the pixel circuit of the first embodiment, and the EL element EL41, the data switching transistor T42, and the driving transistor T41. A driving current from the transistor T45 and the driving transistor T42 to the EL element EL41 for switching the threshold voltage compensation transistor T43, the capacitor C41, the initialization transistor T44, and the power supply voltage VDD. It consists of six transistors and one capacitor, including a transistor T46 for controlling the flow of.

However, the pixel circuit of the organic light emitting display device according to the second embodiment differs only in that all of the switching transistors T42-T46 except the driving transistor T41 are configured as dual gates. Accordingly, the pixel circuit according to the second embodiment can reduce the leakage current by improving the off current characteristic more than when the switching transistor is off.

5 illustrates a first embodiment of a multi-gate thin film transistor according to an exemplary embodiment of the present invention. Referring to FIG. 5, the active layer 110 and the gate electrode 120 are arranged on the insulating substrate 100. The active layer 110 has a “c” shape, consisting of a body portion 110a and a connection portion 110b connecting the body portion 110a, and the gate electrode 120 has a body of the active layer 110. It is arranged to intersect the portion 110a.

Accordingly, the active layer 110 includes a dual channel layer by overlapping the gate electrode 120 with the channel layers 113 and 117, and the gate electrode 120 is connected to the active layer 110. The overlapping portion acts as the gates 123 and 127 to have dual gates. Both sides of the gate electrode 120 of the active layer 110 serve as source regions 111 and 119 and drain regions 115 as impurity regions.

6 illustrates a second embodiment of a multi-gate thin film transistor according to an embodiment of the present invention. Referring to FIG. 6, the active layer 210 and the gate electrode 220 are arranged on the insulating substrate 200. The active layer 210 has a "c" shape consisting of a body portion 210a and a connection portion 210b connecting the body portion 210a, and the gate electrode 220 of the active layer 210 has a shape. One slot 229 intersects the body portion 210a.

Accordingly, the active layer 210 includes a multi-channel layer in which portions overlapping the gate electrode 220 act as channel layers 212, 214, 216, and 218, and the gate electrode 220 is the active layer. A portion overlapping with 210 serves as the gates 222, 224, 226, and 228 to include the multi-gates. Both sides of the gate electrode 220 and portions of the slot 229 of the active layer 210 serve as source regions 211, 215, and 219 and drain regions 213 and 217.

7A and 7B illustrate leakage current characteristics when the switching transistor of the organic light emitting display device according to the exemplary embodiment of the present invention is configured as a dual gate thin film transistor and when the conventional switching transistor is configured as a single gate. . Fig. 7A shows the leakage current characteristics of the switching transistor with respect to the current value flowing through the EL element, and Fig. 7B shows the ratio of the leakage current of the switching transistor to the current value flowing through the EL element. Referring to FIGS. 7A and 7B, as the current flowing through the EL element increases, the leakage current of the switching transistor increases, and it can be seen that the leakage current can be reduced when the dual gate is configured rather than the single gate. .

The pixel circuit which reduces leakage current when the switching transistor is turned off by configuring the switching transistor of the present invention with multiple gates is applicable to the pixel circuit having various configurations. In addition to the P-type thin film transistor, the pixel circuit can be configured not only with an N-type thin film transistor and a CMOS thin film transistor but also with a combination of N-type and P-type transistors.

In addition to the above-described multiple structure, various multiple gate structures may be applied to the switching transistor. In addition, some of the switching transistors may be implemented as thin film transistors having dual gates, and the remaining transistors may be implemented as multiple gates having dual gates or more. On the other hand, the driving transistor may be implemented as a thin film transistor having a conventional single gate.

According to the embodiment of the present invention as described above, by configuring the driving transistor as a single gate and by implementing the switching transistor as multiple gates, it is possible to improve the off-current characteristics of the switching transistor while maintaining excellent on-current characteristics of the driving transistor. There is an advantage to that.

Although described above with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

Claims (17)

A first transistor transferring a data signal of a voltage level in response to a current scan line signal; A second transistor for generating a driving current according to a data signal of a voltage level transmitted through the first transistor; A third transistor for detecting and self-compensating a threshold voltage deviation of the second transistor; A capacitor for storing a data signal of a voltage level transmitted to the second transistor; An EL element emitting light in response to a driving current generated through the second transistor, And the first transistor and the third transistor have multiple gates, and the second transistor has a single gate. The organic light emitting display of claim 1, further comprising an initialization fourth transistor configured to discharge a data signal having a voltage level stored in the capacitor in response to a scan signal immediately before the current scan signal. Pixel circuit. The organic light emitting display device of claim 1, wherein one of the first and third transistors includes a thin film transistor having dual gates, and the other includes a thin film transistor having multiple gates of at least two dual gates. Pixel circuit. 4. The pixel circuit of an organic light emitting display device according to claim 3, wherein the fourth transistor is formed of multiple gates. The semiconductor device of claim 1, further comprising: a fifth transistor configured to provide a power supply voltage to the second transistor in response to a current light emission control signal; And a sixth transistor configured to provide a driving current to the EL element through the second transistor in response to the current light emission control signal. 5. The pixel circuit of an organic light emitting display device according to claim 4, wherein the fifth and sixth transistors are composed of multiple gates. The transistor of claim 1, wherein the first transistor is configured of a PMOS transistor having a current scan line signal applied to a gate, a data signal of a voltage level applied to a source, and a drain connected to the second transistor. Pixel circuit in organic light emitting display device. The organic field of claim 1, wherein the second transistor comprises a PMOS transistor having a gate connected to one terminal of the capacitor, a source connected to the first transistor, and a drain connected to the EL element. Pixel circuit of light emitting display device. The method of claim 8, wherein the third transistor is a current scan signal is applied to the gate and the drain and the source are connected to the gate and the drain of the second transistor, respectively, in response to the current scan signal to connect the second transistor in the form of a diode A pixel circuit of an organic light emitting display device, comprising: a PMOS transistor for self-compensating a threshold voltage. A first transistor transferring a data signal of a voltage level in response to a current scan line signal during data programming; A second transistor for programming a data signal having a voltage level during data programming and generating a driving current in response to the programmed data signal during light emission; A third transistor for providing a data signal having a voltage level to the second transistor in response to a current scan signal during data programming; A capacitor for storing the data signal of the voltage level transmitted to the second transistor for maintaining the data signal of the voltage level programmed in the second transistor during data programming; A fourth transistor for transmitting a power supply voltage to the second transistor during light emission; A fifth transistor configured to transfer a driving current provided from the second transistor according to a data signal having a voltage level during light emission; An initialization sixth transistor configured to discharge a data signal having a voltage level stored in the capacitor in response to a scan signal immediately before the current scan signal; An EL element emitting light in response to a driving current transmitted through the fifth transistor, And the first, third, fourth, fifth and sixth transistors have multiple gates, and the second transistor has a single gate. The thin film transistor of claim 10, wherein some of the first, third, fourth, fifth, and sixth transistors include a thin film transistor having dual gates, and the remaining parts include thin film transistors having multiple gates of at least dual gates. A pixel circuit of an organic light emitting display device. A first transistor to which a current scan signal is applied to a gate, and a data signal of a voltage level to a source; A second transistor having a source connected to the drain of the first transistor; A third transistor having a drain and a source connected between the gate and the drain of the second transistor, respectively; A fourth transistor having a current emission control signal applied to a gate, a power supply voltage applied to the source, and a drain connected to the source of the second transistor; A fifth transistor in which the current light emission control signal is applied to a gate, a source is connected to the drain of the second transistor, and a drain is connected to one terminal of the EL element; A sixth transistor to which a scan signal immediately before the current scan signal is applied to a gate, a source is connected to one terminal of the capacitor, and an initialization voltage is applied to the other terminal; A light emitting device having one terminal connected to the drain of the fifth transistor and the other terminal grounded; One terminal is connected to the gate of the second transistor, and the other terminal includes a capacitor for applying a power supply voltage, The pixel circuit of an organic light emitting display device, wherein the first, third, fourth, fifth, and sixth transistors have multiple gates, and the second transistor has a single gate. 13. The method of claim 12, wherein some of the first, third, fourth, fifth, and sixth transistors include a thin film transistor having dual gates, and the others include thin film transistors having multiple gates of at least dual gates. A pixel circuit of an organic light emitting display device. A first transistor transferring a data signal of a voltage level in response to a current scan line signal; A second transistor for generating a driving current according to a data signal of a voltage level transmitted through the first transistor; A third transistor for detecting and self-compensating a threshold voltage deviation of the second transistor; A capacitor for storing a data signal of a voltage level transmitted to the second transistor; An EL element emitting light in response to a driving current generated through the second transistor, The first transistor and the third transistor are provided with multiple gates, the second transistor has a single gate, The first and third transistors are respectively An active layer having a plurality of body parts and a plurality of connection parts connecting one side of the body part; A gate electrode arranged to intersect the active layer; And a portion of the gate electrode overlapping the active layer serves as a multiple gate. 15. The pixel circuit of claim 14, wherein the gate electrodes of the first and third thin film transistors have at least one slot intersecting the active layer. 15. The organic light emitting display device of claim 14, wherein one of the first and third transistors includes a thin film transistor having dual gates, and the other includes a thin film transistor having multiple gates of at least two dual gates. Pixel circuit. 15. The semiconductor device of claim 14, further comprising: an initialization fourth transistor configured to discharge a data signal having a voltage level stored in the capacitor in response to a scan signal immediately preceding the current scan signal; A fifth transistor for providing a power supply voltage to the second transistor in response to a current light emission control signal; A sixth transistor configured to provide a driving current to the EL element through the second transistor in response to the current light emission control signal, And the fourth to sixth transistors include thin film transistors having multiple gates.

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