TW200907894A - Pixel circuit - Google Patents

Abstract

A pixel circuit includes a first transistor, a second transistor, a switch, a capacitor and an OLED. Each transistor has a first terminal, a second terminal and a control terminal for determining whether the first and second terminals are connected with each other. The control terminal of the first transistor is electrically connected to one terminal of the capacitor. The first terminal of the first transistor, the second terminal of the second transistor and the other terminal of the capacitor are electrically connected with one another. The second terminal of the first transistor is electrically connected to the anode of the OLED. The cathode of the OLED receives a scanning signal. The control terminal of the second transistor receives a reference voltage. The first terminal of the second transistor receives a power signal. The switch receives a data voltage and is controlled by the power signal to determine whether to output the data voltage to the control terminal of the first transistor or not.

Description

200907894 IX. Description of the Invention: [Technical Field] The present invention relates to a pixel circuit, and more particularly to a pixel circuit of an organic light-emitting diode. [Prior Art] Since the organic light-emitting diode (0LED) display has advantages such as self-luminous, high brightness, fast reaction time, and wide viewing angle, it has been gradually taken into consideration and used. >Reading the 0LED display ^ is to display the image by a plurality of pixel circuits arranged in an array and showing different colors, and scanning the pixel circuits step by step or column by column to determine the appearance of each pixel circuit Color form. The mother like the Xin Lei AJ person like the Beijing circuit contains - 〇 LED 1 and - drive circuit 2 'where 'the drive circuit 2 outputs a um ^ ^ drive current Idrive to the OLED 1 ' to make the 0LED 1 emit strength 盥The drive current Idrive is related to the size of the light. The first type of driving lightning circuit 2 includes a first transistor 2〇1, a second transistor 202, and a thunderbolt 203. The first transistor 201 and the second transistor 202 are p-type thin film Thunder-conserving electrical anodes (TFTs), and each of the transistors 201, 202 has a first 鸲, a second end, and a second A control end that is conductive at one end and the second end. ^ The control end of the first electric cell 201 receives a scan letter I tiger SCAN. The first end of the first transistor 201 receives a data voltage VDAT, the second transistor of the first transistor 201, the control terminal of the second transistor 202, and one end of the capacitor 203. The first end of the second transistor 202 and the other end of the capacitor 5 200907894 203 are electrically connected and receive a first power voltage VDD. The second end of the second transistor 202 is electrically connected to the anode of the OLED 1. The cathode of the OLED 1 receives a second supply voltage Vss.

The timing of the drive circuit 2 is as shown in FIG. 2. When the scan signal SCAN is low, the first end and the second end of the first transistor 201 are turned on. At this time, the data voltage VDATA is transmitted to the control end of the second transistor 202, and the capacitor 203 The cross voltage is changed according to the data voltage VDATA. When the scan signal SCAN is high, the first end and the second end of the first transistor 201 are not turned on. At this time, the capacitor 203 maintains its voltage across. The second transistor 202 generates the driving current I according to the voltage across the capacitor 203.

DRIVE as follows:

Wherein, W202/L202 is a width to length ratio of the second transistor 202,

Vc, 203 is the voltage across the capacitor 203 and VTH, 2 〇 2 is the threshold voltage of the second transistor 202. For a pixel circuit using the conventional first driving circuit 2, since the threshold voltages of the second transistors 202 of different pixel circuits are different, different pixels are received when receiving the same data voltage V DATA . The squirming current Idrive generated by the circuit will be different, resulting in different intensity of the emitted light. Moreover, since each power supply line that transmits the first power supply voltage VDD is usually electrically connected to a plurality of halogen circuits in sequence, and the resistance value of the power supply line is not zero, a voltage drop due to a current flowing (IR) Drop ) will make the first power supply voltage Vdd received by different 6 200907894 I roads different. When receiving the relevant material, the driving current drive generated by different pixel circuits will be different. The intensity of the light emitted will also be different. > Referring to Figure 3, a conventional second driving circuit 2 includes a first transistor 211, a first and a second transistor 212 and a capacitor 213. The first transistor 211 μ second transistor 212 is an N-type TFT, and each of the transistors 2ii, 212 has a width of one 碥, a second end, and a determination of whether the first end and the second end are conductive. Control terminal. The control terminal of the first electrical body 211 receives a scan signal SCAN. The first end of the crystal ~ transistor 21i receives - the data voltage % 趟. The first end of the first electrode 211, the control end of the second transistor 212, and the - terminal of the capacitor 13 are electrically connected. The first end of the second transistor 212 receives a first source voltage VDD. The second end of the second transistor 212 is electrically connected to the other end of the capacitor (1) and the anode of the xenon LED 1. The cathode of the OLED 1 receives a second supply voltage Vss.

The timing of the β 3 hai drive circuit 2 is as shown in FIG. 4 . When the scan signal scaN is at a high potential, the first end and the second end of the first transistor 211 are turned on. At this time, the data voltage vDAT^ is transmitted to the control end of the second transistor 212, and the capacitor 213 The voltage across the data is changed according to the voltage ν〇ΑΤΑ. When the SCAN of the SUV is low, the first end and the second end of the first transistor a are not turned on. At this time, the capacitor 213 maintains its voltage across. The second transistor 212 generates the driving current according to the cross-dissipation of the capacitor 213, and the driving current is generated as follows: 200907894 drive^-tMC ~^-(v -V )2 2 ox τ VKC, 213 yTH, 212 / ^212 __ 1 w / = -ZUnCn ~^l(v -V -vy 2 〇xr ^ DATA y OLED yTH 212 / J2\2 where W212/L212 is the aspect ratio of the second transistor 212, v It is the voltage across the capacitor 213 'Vth, 2i2 is the voltage of the second transistor 212::3, and V〇led is the voltage across the OLED 1. For the use of the conventional second driving circuit 2, the halogen In terms of the circuit, since the voltage of the second transistor 2〇2(4) of different pixel circuits will be different, the same bedding power is received. When Vdata is used, the driving current generated by the different pixel circuits is different. , the intensity of the emitted light will be different. And 'the (10)D i of each pixel circuit will age due to long-term operation, so that the voltage across it will gradually rise, which will lead to the driving of the pixel circuit. The current Idrive becomes smaller. Referring to Figure 5', in order to reduce the influence of the critical electric magic variation and the power supply voltage dust drop, the Republic of China invention patent No. 228696 A third type of driving circuit 2" is disclosed. The third driving circuit 2" includes a first transistor, a second transistor 222, a third transistor 223, a fourth transistor 224, a fifth transistor 225 and a capacitor 226. The first to fifth transistors 221 225 225 are P-type TFTs, and each of the transistors 221 225 225 has a first end, a second end, and a The first end and the second end are connected to the control end. The control end of the first transistor 221 receives a current scan signal SCANk. The first end of the first transistor 22! receives the data voltage. The second end of the transistor 221 and the first -200907894 end of the second transistor 222 are electrically connected (hereinafter referred to as point A). The control end of the second transistor 222, the second end of the second transistor 222, The first end of the third transistor 223, the control end of the fourth transistor 224, and one end of the capacitor 226 are electrically connected (hereinafter referred to as point B.) The control terminal of the third transistor 223 receives a previous scan signal. The second end of the third transistor 223 receives a ground voltage. The first end of the fourth transistor 224 and the The other end of the capacitor 226 is electrically connected to receive a first power supply voltage VDD. The second end of the fourth transistor 224 is electrically connected to the first end of the fifth transistor 225. The control end of the fifth transistor 225 A control signal CTRL is received. The second end of the fifth transistor 225 is electrically connected to the anode of the OLED 1. The cathode of the OLED 1 receives a second supply voltage Vss. The timing of the driving circuit 2" is as shown in Fig. 6. When the previous scanning signal SCANy is low, the current scanning signal SCANk is high and the control signal CTRL is high, the first of the third transistor 223 The first end and the second end of the first transistor 221 are not turned on, and the first end and the second end of the fifth transistor 225 are not turned on. At this time, the ground voltage is transmitted. Go to point B, and the driving current Idrive is not generated by the fourth transistor 224. When the previous scanning signal SCANk-i is the south potential, the current scanning signal SCANk is low, and the control signal CTRL is high, the first The first end and the second end of the first transistor 221 are not turned on, and the first end and the second end of the first transistor 221 are turned on, and the first end and the second end of the fifth transistor 225 are not turned on. When the 'data voltage Vdata is transmitted to point A' and the voltage of point B is raised through the second transistor 222 until the power at point B is 200907894

Voltage=the data voltage VDATA-|the threshold voltage I of the second transistor 222, and the fourth transistor 224 does not generate the driving current I DRIVE ° When the previous scan signal SCANw is high, the current scan signal SCANk is When the control signal CTRL is low, the first end and the second end of the third transistor 223 are not turned on, and the first end and the second end of the first transistor 221 are not turned on, and the fifth The first end and the second end of the transistor 225 are turned on. At this time, the capacitor 226 maintains its voltage across the capacitor, and the fourth transistor 224 generates the driving current Idrive according to the voltage across the capacitor 226.

Wherein, W224/L224 is the width to length ratio of the fourth transistor 224, VC, 226 is the voltage across the capacitor 226, VB is the voltage at point B, and VTH, 224 is the threshold voltage of the fourth transistor 224. Vth, 222 is the threshold voltage of the second transistor 222. Since the position of the second transistor 222 and the fourth transistor 224 are very close, the threshold voltages thereof can be regarded as the same, and therefore, T DRIVE = 5 M pCox - 224 '(^DD-^DATA). 224. For a pixel circuit using the conventional third driving circuit 2", the influence of the threshold voltage of the fourth transistor 224 of each pixel circuit on the driving current Idrive is affected by the second power of the pixel circuit. The threshold voltage 10 200907894 of the crystal 222 is eliminated. Moreover, the power line (9) transmitting the first power supply M ^ receives the same scanning signal SCANk·, SCANk pixel circuit due to the power supply (4) The circuit of the main circuit is written to the data voltage VD at the same time, and the current of the driver A is not generated, and the current flowing through the power line of the browser Idrive is 〇, so that the pixels are defeated. The first power supply voltage VDD received by the circuit is the same, and the voltage drop of the first power supply voltage VDD can be divided into four: the capacitance of the voltage circuit: the influence of the voltage. When receiving the same data voltage VDATA, different The driving current generated by the denier circuit will be the same, resulting in the same intensity of the emitted light. Although the third driving circuit 2" can reduce the influence of the threshold voltage variation and the voltage drop of the power supply voltage, it is better than the first Drive electric @ 2 and the first A driving circuit 2 that uses three transistors in a large amount such that an aperture ratio (i.e., an area ratio of an effective light-emitting display area) of the OLED display is lowered, resulting in deterioration of light use efficiency. SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a pixel circuit that compensates for the effects of threshold voltage variation and eliminates the effects of voltage drop of the power supply voltage, and increases the aperture ratio and the lifetime of the OLED. Therefore, the pixel circuit of the present invention comprises a first transistor, a second transistor, a switch, a capacitor and an LED. Each of the transistors has a first end, a second end, and a control end that determines whether the first end and the second end are conductive. The control end of the first transistor and one end of the capacitor are electrically connected. The first end of the first transistor, the second end of the second transistor, and the other end of the capacitor 200907894 are electrically connected. The second end of the first transistor is electrically connected to the anode of the OLED. The cathode of a myo 0LED receives a scan signal. The control terminal of the second transistor receives a reference voltage. A first end of the second transistor receives a power signal. The switch receives a data voltage and is controlled by the power signal to determine whether to output the data voltage to the control terminal of the first transistor. Another object of the present invention is to provide a pixel circuit that compensates for the effects of threshold voltage variations and eliminates the effects of supply voltage drop. The pixel circuit of the present invention comprises a first transistor, a second transistor, a switch, a capacitor and a light-emitting element. Each of the transistors has a first turn, a first end, and a control end that determines whether the first end and the second end are conductive. The light emitting element has an anode and a cathode. The control end of the first transistor and one end of the capacitor are electrically connected. The first end of the first transistor, the second end of the second transistor, and the other end of the capacitor are electrically connected. The second end of the first transistor is electrically connected to the anode of the light emitting element. The cathode of the light emitting element receives a scan signal. The control terminal of the second transistor receives a reference voltage. The first terminal of the third transistor receives a power signal. The switch receives the data voltage and is controlled by the power signal to determine whether to output the data voltage to the control terminal of the first transistor. Another object of the present invention is to provide a pixel circuit capable of compensating for the voltage of the junction boundary The effect of variation and the elimination of the effects of aging of LEDs, and increased aperture ratio and OLED lifetime. Thus, the pixel circuit of the present invention comprises a first transistor, a second transistor, a switch, a capacitor, and an OLED. Each transistor has a - _ 12 200907894 鳊, a second terminal and a control terminal that determines whether the first terminal and the second terminal are conductive. The control end of the first transistor and one end of the capacitor are electrically connected. The first end of the first transistor receives a power signal. The second end of the first transistor, the first end of the second transistor, and the other end of the capacitor are electrically connected. The control terminal of the second transistor receives a reference voltage. The first turn of the second transistor and the anode of the OLED are electrically connected. The cathode of the LED receives a scan signal, and the switch receives a data voltage and is controlled by the power signal to determine whether to output the data voltage to the control terminal of the first transistor. Another object of the present invention is to provide a pixel circuit that compensates for the effects of threshold voltage variations and eliminates the effects of aging of the light-emitting elements. In the present invention, the pixel circuit of the present invention comprises a first transistor, a second transistor, a switch, a capacitor and a light-emitting element. Each of the transistors has a first end, a second end, and a control end that determines whether the first end and the second end are conductive. The light emitting element has an anode and a cathode. The control end of the first transistor is electrically connected to the terminal of the capacitor. The first end of the first transistor receives a power signal. The second end of the first transistor, the first end of the second transistor, and the other end of the capacitor are electrically connected. The control terminal of the second transistor receives a reference voltage. The second end of the second transistor is electrically connected to the anode of the light emitting element. The cathode of the illuminating element receives a -scan signal. The switch receives a data voltage and is controlled by the power signal to determine whether to output the data voltage to the control of the first transistor: 〇 [Embodiment] 13 200907894 Related to the present invention The following reference is clearly presented. In the detailed description of the two preferred embodiments of the foregoing and other technical contents, features and power diagrams, the first preferred embodiment of the pixel circuit of the present invention comprises a transistor 31, . ^ Brother a transistor 32, a switch 30, a capacitor 34 months OLED 35. The 开关 ^ h » hai switch 30 includes a third transistor 33. The first to third transistors 31 to 3 ^ 3 疋 P-type TFTs, and each of the transistors 31 to 33 and a first end, a 筮山弟 know and determine whether the first end and the second end The control terminal that is turned on. * The control terminal of the second transistor 33 and the first terminal of the second transistor 32 are electrically connected 'and receive the power supply signal PVDD. The first end of the third transistor 33 receives the data waste Vdata. The second end of the third transistor 、, the control terminal of the first transistor 31, and the terminal of the capacitor 34 are electrically connected (hereinafter referred to as point C). The first end of the first transistor 31, the second end of the second transistor 32, and the other end of the capacitor 34 are electrically connected (hereinafter referred to as point d). The second end of the first electro-optic crystal unit 31 and the anode of the x-ray LED 35 are electrically connected. The cathode of the OLED 35 receives a scan signal SCan. The control terminal of the second transistor 32 receives a reference voltage vre. The timing of the first preferred embodiment is as shown in FIG. 8, and can be divided into three phases: I. Preparation phase When the power supply signal PVDD is high and the sweep potential is high, the first of the third transistor 33 And the second end; the conduction, the second end of the second transistor 32 is electrically connected to the second end of the second transistor 32. At this time, the power of the d point is 14 200907894 - the power signal is ancient and the first electric body, the inner Bit, the capacitor 34 maintains its crossover, WE. ΘΗ 丨 generates-drives the driving current of the 〇LE〇35. II. Data input stage. When the power supply signal PVDD is φ / 疋 low and the scanning analogy d r1 δ at b is high, the third electric 1. Say SCAN is the first - electricity day! * Μ Day, the first end and the second end are turned on, and the first azole of the Japanese body 32 is philosophical, and the second end is not conductive. At this time, the data pressure Vdata is transmitted to the c. Soft, the voltage of the ancient point of the 4th tf electric power of the η machine is reduced from the potential of the power supply signal PVDD to the reference voltage H β VIII 1 The critical voltage of the second transistor 32 is reversed The bias voltage produces the drive snow 4 T per reverse and 6 haidi - the transistor 31 does not become a fine robber into Idrive.发光. Illumination phase When the power signal PVDD is its potential t 4 # 疋 A potential and the scan signal SCAN is low, the first end and the second end of the third transistor 33 are not conducting, and the second The first end and the second end of the transistor 32 are turned on. At this time, the capacitor μ maintains its voltage across, and the voltage 35 is forward biased, and the first transistor η generates the driving current Idrive, as shown below. : 2MpC〇x

T DRIVE

, 34 -|factory ττ/,31 丨 data

K 77/, 31 wherein w31/l31 is the aspect ratio of the first transistor 31, v^ is the voltage across the capacitor 34, VTH, 31 is the threshold voltage of the first transistor 31, and VTH'32 It is the threshold voltage of the second transistor 32. Since the position of the first transistor Μ and the second transistor 32 is very close to its critical voltage, the pressure can be regarded as the same, therefore,

DRIVE 2

Mpch-V surface) 2

L 31 In each pixel circuit, the influence of the threshold voltage of the first transistor 31 on the driving current IDRIVE is eliminated by the threshold voltage of the second transistor; Moreover, since each of the signal lines transmitting the reference voltage VREF does not have a current flowing, the reference voltage VREF does not generate a voltage drop, so that the reference voltage VREF received by the different pixel circuits is the same. When receiving the same data voltage VDATA, the drive current I DRIVE generated by the different pixel circuits will be the same, resulting in the same intensity of the emitted light. When the high potential of the power supply signal PVDD = 9V, the low potential of the power supply signal PVDD = -18V, the high potential of the scan signal SCAN = 9V, the low potential of the scan signal SCAN = -6V, the reference voltage = -6V, The data voltage VDATA=-6.25V~-8.75V, the width ratio of the first transistor 31=4μιη/25μηι, the width ratio of the second transistor 32=4μιη/60μηι, the third transistor 33 The width to length ratio = 4μιη / 4μιη, the capacitance value of the capacitor 34 = 0.5pF, and the threshold voltage offset of the transistors 31 to 33 is 0V, -0.3V and +0.3 V 'the driving current ID RIV E The simulation results are shown in Figure 9. As can be seen from Fig. 9, this embodiment can surely make the driving current Idrive generated by different pixel circuits the same. It should be noted that this embodiment can be used to drive other current-driven light-emitting elements, such as light-emitting diodes (LEDs), in addition to driving the OLED 35, and the transistors 31 to 33 are in addition to In addition to the P-type TFT, a P-type metal oxide semiconductor (PMOS) may also be used. 16 200907894 Referring to FIG. 10, the first preferred embodiment of the present invention, such as the Sinley-Technology, includes a transistor 41, a second transistor, a solar cell, a switch 40, and a capacitor 44. ◦led 45. The switch 4 is 〇-衽-two η 馇 馇 _ second transistor 43. The first and the lower brothers a transistor 41, 42 are Ν type tft, #结^ 疋ίΝ圭 TFT, the third transistor 43 is the earth ur, and each transistor 41~43 has a brother a terminal, a second terminal, and a control terminal that determines whether the first terminal and the second terminal are conductive. (9) The control terminal of the third transistor 43 and the first transistor connection of the first transistor 41 and receive the power supply signal PVDD. The first end of the third transistor 43 receives a billet voltage Vdata. The second end of the third transistor, the control end of the first transistor 41 and the one end of the capacitor 44 are electrically connected (hereinafter referred to as point E). The second end of the first transistor 4A, the first end of the second transistor 42, and the other end of the capacitor 44 are electrically connected (hereinafter referred to as point f). The control terminal of the second transistor 42 receives a reference voltage Vrej, and the second end of the first electrical body 42 and the anode of the LED 45 are electrically connected. The cathode of the OLED 45 receives a scan signal scan. The timing of the second preferred embodiment of FIG. 5 is as shown in FIG. 11 and can be divided into three stages: I. Preparation stage

When the power signal PVDD is low and the scan signal SCAN is low, the first end and the second end of the third transistor 43 are turned on, and the first end and the second end of the second transistor 42 are turned on. At this time, the data voltage vdata is transmitted to the E point, the voltage of the F point = the low potential of the scan signal SC AN + the voltage across the OLED 45, the OLED 45 is forward biased, and the first transistor 41 does not generate a drive current for driving the 〇leD 45 IDRIVE 17 200907894 II. Data input phase when the § hai power signal PVDD is low and the scan signal SCAN is the potential, 'the third transistor 43 # first end and The second end is turned on, and the first end and the second end of the 苐-transistor 42 are not turned on. At this time, the data voltage vDATA is transmitted to the E point, and the energy of the F point is low of the scan signal + the OLED The 5th look of 45 is known to return to the reference voltage vREF_ the threshold voltage of the first transistor 42, continued 〇τ Ρ1Ί 4, the electric & ULED 45 is reverse biased, And the first transistor 41 does not generate the driving current Idrive.发光. Illumination phase When the power signal PVDD county Gulei # 4 body, the inter-turn potential and the known signal SCAN is low, the second thunder and 12 & - the first body of the electric body 43 The terminal and the second end are not conductive, and the first end of the first transistor 42 "cage_·# channel, s J ^鲕 and the other end of the body are turned on. At this time, the capacitor 44 crosses the pressure, and (4) (four) 45 is turned to the money. And the first - transistor twins "Hills current Lrive, as follows: [drive 2^Cox^-(vc44-Vm4lf 2 'Rabbit

L ΤΑ '41 + VTH, , 42 Λ 41, where W41/L4i is the first transistor 4 3 of the capacitor 44, the length ratio Vc, 44 疋 and ν θ 4, VtH'41 is the first The critical electric dust of the transistor 4!, the body: 1 ... the threshold voltage of the second transistor 42. Due to the first-electrode crystal, the position of the second transistor 42 is very similar and can be regarded as the same. Therefore, the special critical voltage is 18 200907894 I drl

VE 2 ^η^οχ~^~(νϋΑΤΑ ~^REF ) 2 ^41 In the mother-single circuit, the influence of the threshold voltage of the first transistor 41 on the driving current IDRIVE is affected by the second transistor The threshold voltage elimination field of 42 receives the same feed voltage Vdata, and the drive current IDRIVE generated by different pixel circuits will be the same, resulting in the same intensity of the emitted light and the drive current generated by the pixel circuit. IDRIVE is not affected by the voltage across the OLED 45, and the drive current idrive becomes smaller due to the aging of the 〇led 45 material. It should be noted that this embodiment can be used to drive other current-driven light-emitting elements, such as the one-handed body (LED), in addition to driving the QLED 45, and the transistors Μ, 42 In addition to the n-type tft, a metal oxide semiconductor (NM〇s) may be used, and the transistor 43 may be pM〇s in addition to the P-type TFT. In summary, the embodiments of the present invention can eliminate the effect of the threshold voltage variation of the first transistor on the driving current, and can also eliminate the voltage drop of the power supply or the effect of the LED aging on the driving current. Further, the embodiments of the present invention can increase the aperture ratio by using two transistors less than the pixel circuit of the conventional third driving circuit. Moreover, the embodiments of the present invention cause the xenon LED to be reverse biased over a period of time to release the charge accumulated within the OLED to increase the useful life of the enamel. Therefore, the object of the present invention can be achieved. The above is only the preferred embodiment of the present invention, and the scope of the present invention is not limited thereto, that is, the invention is based on the scope of the invention and the scope of the invention. Within the scope of coverage. [Simple diagram description] Single specific effect change and modification are still shown in Fig. 1 is a circuit diagram of a conventional pixel circuit. Fig. 2 is a timing chart of the pixel circuit of Fig. 1. Fig. 3 is a circuit diagram of another conventional pixel circuit. 4 is a timing diagram of a pixel circuit of FIG. 3; FIG. 5 is a circuit diagram of another conventional pixel circuit; FIG. 6 is a timing chart of the pixel circuit of FIG. FIG. 8 is a timing diagram of the first preferred embodiment; FIG. 9 is a schematic diagram of the first preferred embodiment; FIG. 9 is a circuit diagram of a second preferred embodiment of the present invention; Timing diagram of the second preferred embodiment 20 200907894 [Description of main component symbols] 3 0......switch 31~33····Optosystem 34 .........capacitance

35 .........OLED

40.........Switch 41~43···, transistor 44 .........capacitor 45 .........OLED 21

Claims (1)

200907894 X. Patent application scope: 1. A pixel circuit comprising: a first electric anode and a second transistor, each transistor having - a first end, a second end and - determining the first end and the first a control terminal that is turned on at the two ends; a switch; a capacitor; and an organic light emitting diode; wherein the control end of the first transistor is electrically connected to one end of the capacitor, the first end of the first transistor, The second end of the second transistor and the other end of the electric valley are electrically connected to the second end of the first transistor and the anode of the organic first diode, and the cathode of the organic light emitting diode Receiving a scan signal, the control end of the second transistor receives a reference voltage, and the first end of the second transistor receives a power signal, and the switch is connected A body voltage is received and controlled by the power signal to determine whether to output the tributary voltage to the control terminal of the first transistor. 2. The pixel circuit according to claim 1, wherein the first transistor and the second transistor are P-type thin germanium transistors. 3. The pixel circuit of claim 3, wherein the switch comprises a third transistor, the third transistor having a first end, a second end, and a first end and The control end of the third transistor receives the power signal, the first end of the third transistor receives the data electrode, and the second end of the third transistor is electrically connected to the control terminal The control end of the first transistor. 22 200907894 4. According to the pixel circuit of claim 3, the electro-optical body, the 5th second transistor and the third transistor are p-electrons. I溥骐5. According to the pixel circuit described in the scope of the patent application, the dragon/A, the transistor and the switch have only one conduction at a time, and in the first body = the current is generated to drive The pixel circuit of claim 5, wherein the first transistor and the second transistor are p-type thin film transistors. The pixel circuit of claim 5, wherein the switch comprises a third transistor, the third transistor has a first end, a second end, and a first end and the first The control terminal of the third transistor receives the power signal, the first terminal of the third transistor receives the data voltage, and the second terminal of the third transistor is electrically connected to the first The control end of the transistor. 8. The pixel circuit of claim 7, wherein the second transistor, the second transistor, and the third transistor are both P plastic film t 曰.gdtr. The pixel circuit includes: a first transistor and a second transistor, each transistor having a first end, a second end, and a determining whether the first end and the second end are conductive a control unit; a switch; a capacitor; and 23 200907894 a light-emitting element having an anode and a cathode; wherein 'the control end of the first transistor and one end of the capacitor are electrically connected, the first end of the first transistor The second end of the second transistor and the other end of the capacitor are electrically connected, the second end of the first transistor is electrically connected to the anode of the light emitting device, and the cathode of the light emitting element receives a scan signal, δ The control end of the first transistor receives a reference voltage, the first end of the second electrode receives a power signal, and the switch receives a data voltage and controls the power signal to determine whether to output the data voltage to The control terminal of the first transistor. The pixel circuit of claim 9, wherein the first transistor and the second transistor are both Ρ-type thin film transistors. The pixel circuit of claim 9, wherein the first transistor and the second transistor are both erbium-type metal oxide semiconductors. 12. The pixel circuit of claim 9, wherein the switch comprises a third transistor, the third transistor having a first end, a first turn, and a first end and the The control terminal of the third transistor receives the power signal, the first terminal of the third transistor receives the data voltage, and the second terminal of the third transistor is electrically connected to the first The control end of a transistor. 13. The pixel circuit of claim 12, wherein the second electrode, the second transistor, and the third transistor are p-type thin transistors. 14. The pixel circuit of claim 12, wherein the first transistor, the second transistor, and the third transistor are both p-type metal 24 200907894 oxide semiconductor. The pixel circuit according to claim 9, wherein the diode and the switch are only turned on at a time, and the switch is turned on when the transistor does not generate a current to drive the light emitting device. . 16. The pixel circuit of claim 15, wherein the first transistor and the second transistor are P-type thin film transistors. 17. The pixel circuit of claim 15, wherein the first transistor and the second transistor are both P-type metal oxide semiconductors. The pixel circuit of claim 15, wherein the switch comprises a second transistor, the second transistor has a first end, a second end, and a first end And the control end of the third transistor is configured to receive the power signal, the first end of the third transistor receives the data voltage, and the second end of the third transistor is electrically connected to The control end of the first transistor. The pixel circuit of claim 18, wherein the first transistor, the second transistor, and the third transistor are P-type thin film transistors. The pixel circuit of claim 18, wherein the first transistor, the second transistor, and the third transistor are all P-type metal oxide semiconductors. A pixel circuit comprising: a first transistor and a second transistor, each transistor having a first end, a second end, and a determining whether the first end and the second end are conductive Control terminal; 25 200907894 a switch; a capacitor; and an organic light emitting diode; wherein 'the control end of the first transistor and one end of the capacitor are electrically connected', the first end of the first transistor receives a power signal The second end of the first transistor, the first end of the second transistor, and the other end of the capacitor are electrically connected, and the control end of the second transistor receives a reference voltage, and the second transistor The second end and the anode of the organic light emitting diode are electrically connected. The cathode of the organic light emitting diode receives a scan signal, and the switch receives a data voltage and is controlled by the power signal to determine whether to output the data voltage to the The control end of the first transistor. 22. The pixel circuit of claim 21, wherein the first transistor and the second transistor are both N-type thin film transistors. The pixel circuit of claim 21, wherein the switch comprises a third transistor, the third transistor has a first end, a second end, and - the first end and the The control terminal of the second transistor that receives the second terminal receives the power signal, the first terminal of the third transistor receives the data voltage, and the second terminal of the third transistor is electrically connected to the The control end of the first transistor. The pixel circuit according to claim 23, wherein the first electric scorpion body and the second electromagnet are N-type thin film transistors, and the third electro-transistor is a P-type thin film electric Crystal. 25. The pixel circuit according to claim 21, wherein the second transistor and the switch are not non-conducting at the same time, and the first transistor generates current when the switch does not conduct 26 200907894. The pixel circuit according to claim 25, wherein one of the transistor and the second transistor are N-type thin wins + ', and a transistor. The pixel circuit of claim 25, wherein the switch comprises a third transistor, the third transistor has a first end, a second end A-determining the first end, and the The control terminal of the third transistor receives the power signal, the first end of the third transistor receives the data voltage, and the second end of the third transistor is electrically connected to the first The control end of a transistor. The pixel circuit of claim 27, wherein the first transistor and the second transistor are both N-type thin germanium transistors, and the third transistor is a P-type thin film transistor. 29. A pixel circuit comprising: a first transistor and a second transistor, each transistor having a first end, a second end, and a control for determining whether the first end and the second end are conductive a switch; a capacitor; and a light-emitting element having an anode and a cathode; wherein the control end of the first transistor and one end of the capacitor are electrically connected to the first end of the first transistor receiving a power source a signal, a second end of the first transistor, a first end of the second transistor, and another end of the capacitor are electrically connected, and a control end of the second transistor receives a reference voltage, the 27 200907894 second transistor The second end is electrically connected to the anode of the illuminating element 70, and the cathode of the first 7L piece receives a scanning signal, and the switch receives a data voltage ' and is controlled by the power signal to determine the β 兮^ In order to determine whether to output the data voltage to the control terminal of the first transistor. 30. The pixel circuit of claim 29, wherein the first transistor and the second transistor are thin film transistors. The pixel circuit of claim 29, wherein the first transistor and the second transistor are both bismuth metal oxide semiconductors. The pixel circuit of claim 29, wherein the switch comprises a second transistor, the third transistor has a first end, a f-th end, and a first end and the first The control terminal of the second transistor is connected to the control terminal of the second transistor, the first terminal of the third transistor receives the data voltage, and the second terminal of the third transistor is connected to the first terminal The control end of a transistor. The pixel circuit of claim 32, wherein the first transistor and the second transistor are both N-type thin film transistors, and the second transistor is a p-type thin film transistor. The pixel circuit of claim 32, wherein the first transistor and the second transistor are both N-type metal oxide semiconductors, and the third transistor is a P-type metal oxide semiconductor . The pixel circuit of claim 29, wherein the first electrode body and the switch are not non-conducting at the same time, and the first transistor generates current to drive when the switch is not conducting. The light emitting element. The pixel circuit according to claim 35, wherein the 28th 200907894 transistor and the second transistor are N-type thin germanium transistors. The pixel circuit of claim 35, wherein the first transistor and the second transistor are both N-type metal oxide semiconductors. The pixel circuit of claim 35, wherein the switch comprises a third transistor, the third transistor has a first end, a first end, and a first end and the first The control end of the third transistor receives the power signal, the first end of the third transistor receives the data voltage, and the second end of the third transistor is electrically connected to the first The control end of the transistor. The pixel circuit of claim 3, wherein the first transistor and the second transistor are N-type thin film transistors, and the third transistor is a P-type thin film transistor . 40. The pixel circuit of claim 3, wherein the first transistor and the second transistor are both N-type metal oxide semiconductors, and the second transistor is a P-type metal oxide. Semiconductor 29