CN104240644B - Light emitting diode pixel circuit and driving method thereof - Google Patents

Abstract

A light emitting diode pixel circuit and a driving method thereof. The circuit comprises a first transistor, a second transistor, a third transistor, a fourth transistor, a first capacitor, a second capacitor and a light emitting diode. Each of the control terminals of the first to third transistors receives a different control signal, respectively. The first terminal of the first transistor receives a data potential or a reference potential. The first end of the second transistor is coupled to the first operating power supply. The fourth transistor is coupled to the second terminal of the second transistor, the second terminal of the third transistor and the second terminal of the first transistor. The first ends of the first and second capacitors are coupled to the control end of the fourth transistor, and the second ends of the first and second capacitors are coupled to the second end and the first end of the third transistor, respectively. The capacitance value of the second capacitor is larger than that of the first capacitor. The first and second ends of the light emitting diode are respectively coupled to the second end of the fourth transistor and the second operating power supply. The light emitting diode pixel circuit can avoid the problems of reduction of light emitting current of the light emitting diode, slow compensation speed and the like.

Description

LED pixel circuit and driving method thereof

technical field

The present invention relates to a pixel circuit, in particular to a light emitting diode pixel circuit and a driving method thereof.

Background technique

In the light-emitting diode pixel circuit, the pixel circuit architecture can be realized by using a light-emitting diode with four transistors and two capacitors, that is, the so-called 4T2C circuit architecture. In the 4T2C circuit structure, one of the transistors is used as a driving transistor, and one of the capacitors is electrically coupled between the control terminal and the source terminal of the driving transistor. When the 4T2C circuit structure is finished writing data and the light-emitting diode is to be made to emit light, the control terminal of the driving transistor is floated and electrically coupled between the control terminal and the source terminal of the driving transistor. The capacitor is used to couple the voltage change of the source terminal of the driving transistor to the control terminal of the driving transistor, so as to compensate (or eliminate) the influence of the cross-voltage of the light-emitting diode itself and the threshold voltage (Vt) of the driving transistor on the luminous brightness.

However, since each transistor has its own parasitic capacitance, when the light-emitting diode is turned on, the capacitance electrically coupled between the control terminal and the source terminal of the driving transistor is coupled to the voltage of the control terminal from the source terminal of the driving transistor. , it will be divided by the above-mentioned parasitic capacitance (this can be called the parasitic capacitance effect), resulting in poor effect of the above-mentioned compensation. In order to solve the above problems, it is necessary to increase the capacitance value of the capacitor electrically coupled between the control terminal and the source terminal of the drive transistor, for example, increase the capacitance value of the capacitor between the control terminal and the source terminal of the drive transistor to Ct , but this will further lead to problems such as the reduction of the light-emitting current of the light-emitting diode and the slowing down of the compensation speed.

Contents of the invention

The invention provides a light-emitting diode pixel circuit, which can avoid problems such as reduction of the light-emitting current of the light-emitting diode and slow compensation speed.

The present invention further provides a driving method suitable for the LED pixel circuit.

The present invention provides an LED pixel circuit, which includes a first transistor, a second transistor, a third transistor, a fourth transistor (used as a driving transistor), a first capacitor, a second capacitor, and a LED. The first transistor has a control terminal, a first terminal and a second terminal, and the control terminal of the first transistor is electrically coupled to the first control signal, and the first terminal of the first transistor is used for receiving a data potential or a reference potential. The second transistor has a control terminal, a first terminal, and a second terminal, and the control terminal of the second transistor is electrically coupled to the second control signal, and the first terminal of the second transistor is electrically coupled to the first operating power supply. . The third transistor has a control terminal, a first terminal, and a second terminal, and the control terminal of the third transistor is electrically coupled to the third control signal. The fourth transistor has a control terminal, a first terminal, and a second terminal, and the first terminal of the fourth transistor is electrically coupled to the second terminal of the second transistor, and the second terminal of the fourth transistor is electrically coupled to the first terminal. The second terminal of the three transistors, and the control terminal of the fourth transistor is electrically coupled to the second terminal of the first transistor. The first capacitor has a first terminal and a second terminal, the first terminal of the first capacitor is electrically coupled to the control terminal of the fourth transistor, and the second terminal of the first capacitor, the second terminal of the fourth transistor and the third The second ends of the transistors are electrically coupled together. The second capacitor has a first end and a second end, and the first end of the second capacitor, the second end of the first transistor, and the first end of the first capacitor are electrically coupled together, and the second end of the second capacitor Electrically coupled to the first terminal of the third transistor. In addition, the capacitance of the second capacitor is greater than the capacitance of the first capacitor. The light emitting diode has a first end and a second end, and the first end of the light emitting diode is electrically coupled to the second end of the fourth transistor, and the second end of the light emitting diode is electrically coupled to the second operating power source.

The present invention also proposes a light-emitting diode pixel circuit, which includes the first transistor, the second transistor, the third transistor, the fourth transistor, the first capacitor, the second capacitor, and the light-emitting diode, and has the same electrical In addition to the sexual coupling relationship, it further includes a fifth transistor. The fifth transistor has a control terminal, a first terminal and a second terminal, and the control terminal of the fifth transistor receives the fourth control signal, the first terminal of the fifth transistor is electrically coupled to a preset potential, and the first terminal of the fifth transistor is electrically coupled to a preset potential. The two terminals are electrically coupled to the first terminal of the third transistor.

The present invention further provides a light emitting diode pixel circuit, which includes: a first transistor, a second transistor, a third transistor (used as a driving transistor), a light emitting diode and a capacitor module. The first transistor has a control terminal, a first terminal and a second terminal, and the control terminal of the first transistor is electrically coupled to the first control signal, and the first terminal of the first transistor is used for receiving a data potential or a reference potential. The second transistor has a control terminal, a first terminal and a second terminal, and the control terminal of the second transistor is electrically coupled to the second control signal, and the first terminal of the second transistor is electrically coupled to the first operating power supply. The third transistor has a control terminal, a first terminal and a second terminal, and the first terminal of the third transistor is electrically coupled to the second terminal of the second transistor, and the control terminal of the third transistor is electrically coupled to the first terminal. the second terminal of the transistor. The light emitting diode has a first end and a second end, and the first end of the light emitting diode is electrically coupled to the second end of the third transistor, and the second end of the light emitting diode is electrically coupled to the second operating power source. The capacitor module is electrically coupled between the control terminal and the second terminal of the third transistor, and the capacitor module is used to provide an equivalent capacitance between the control terminal and the second terminal of the third transistor, and the capacitor module is in the diode pixel The equivalent capacitance provided by the circuit during the reset period and the light emitting period is greater than the equivalent capacitance provided by the diode pixel circuit during the compensation period and the data writing period.

The present invention further proposes a driving method of an LED pixel circuit, which is used to drive the above LED pixel circuit with the first to fourth transistors. The driving method includes: during the reset period, causing the first operating power supply to provide a first potential, and turn on the first transistor, the second transistor and the third transistor, and simultaneously provide a reference potential to the first terminal of the first transistor; During the compensation period, the first operating power supply provides a second potential, the second potential is greater than the aforementioned first potential, the first transistor and the second transistor are turned on, and the third transistor is turned off at the same time, and a reference potential is provided to the first transistor. The first end of a transistor; during the data writing period, the first operating power supply provides the second potential, and turns on the first transistor and the third transistor, and turns off the second transistor, wherein the first transistor and the third transistor are parallel Not conducting at the same time, and the conduction time of the first transistor is earlier than the conduction time of the third transistor, and providing a data potential to the first terminal of the first transistor when the first transistor is turned on; and, during the light-emitting period, The first operating power supply provides the second potential, turns off the first transistor, turns on the second transistor and the third transistor, and provides a reference potential to the first terminal of the first transistor. Wherein, the reset period is prior to the compensation period, the compensation period is prior to the data writing period, and the data writing period is prior to the light emitting period.

The present invention further proposes a driving method of a light emitting diode pixel circuit, which is used to drive the above light emitting diode pixel circuit with the first to fifth transistors. The driving method includes: during the reset period, turning on the first transistor, The third transistor and the fifth transistor simultaneously provide a reference potential to the first terminal of the first transistor; during the compensation period, the first transistor and the second transistor are turned on, and the third transistor and the fifth transistor are simultaneously turned off, and a reference potential is provided To the first end of the first transistor; during the data writing period, turn on the first transistor and the third transistor, and turn off the second transistor and the fifth transistor, wherein the first transistor and the third transistor are not turned on at the same time, And the turn-on time of the first transistor is earlier than the turn-on time of the third transistor, and when the first transistor is turned on, the data potential is provided to the first end of the first transistor; and, during the light-emitting period, the first transistor and the first transistor are turned off The fifth transistor turns on the second transistor and the third transistor, and provides a reference potential to the first terminal of the first transistor. Wherein, the reset period is prior to the compensation period, the compensation period is prior to the data writing period, and the data writing period is prior to the light emitting period.

In the circuit structure of the light-emitting diode pixel circuit of the present invention, for example, a capacitor module composed of two capacitors and a transistor is used to electrically couple between the control terminal and the source terminal of the driving transistor, and the transistor is used to determine Whether the above two capacitors are electrically coupled between the control terminal and the source terminal of the driving transistor, or only one of the capacitors is electrically coupled between the control terminal and the source terminal of the driving transistor, so that the light emitting diode During different operation periods of the pixel circuit, the capacitance value of the equivalent capacitance electrically coupled between the control terminal and the source terminal of the driving transistor is changed. Accordingly, as long as the transistor is turned on during the reset period and the light-emitting period so that the above-mentioned two capacitors are connected in parallel, and the transistor is turned off during the remaining two periods, then the light-emitting diode pixel circuit of the present invention can avoid the problem of the conventional technology. The light-emitting current of the light-emitting diode is reduced, and the compensation speed is slowed down.

Description of drawings

FIG. 1 shows a circuit structure diagram of an LED pixel circuit according to an embodiment of the present invention;

FIG. 2 is one signal timing diagram of the LED pixel circuit shown in FIG. 1;

FIG. 3 is a circuit structure diagram of an LED pixel circuit according to another embodiment of the present invention;

FIG. 4 is one signal timing diagram of the LED pixel circuit shown in FIG. 3;

FIG. 5 is one of the operation procedures of one of the LED pixel circuits of the present invention;

FIG. 6 is an operation flow of another LED pixel circuit of the present invention.

[Description of main component reference signs]

100, 200: Light-emitting diode pixel drive circuit

11, 12, 13, 14, 15: Transistors

C1, C2, C3: capacitance

20: LED

110, 120, 130, 140, 150: control terminal

111, 121, 131, 141, 151, C11, C21, C31, 201: first end

112, 122, 132, 142, 152, C12, C22, C32, 202: second end

Scan, EM, Reset1, Reset2: control signal

Data: data signal Vdata: data potential Vref: reference potential

Vsus: preset potential OVDD, : Operating power

OVDDH, OVDDL, H, L: potential

G, S: node

t: preset time

501, 502, 503, 504, 601, 602, 603, 604: steps

detailed description

FIG. 1 is a circuit structure diagram of an LED pixel circuit according to an embodiment of the present invention. As shown in FIG. 1 , the LED pixel circuit 100 includes a transistor 11 , a transistor 12 , a transistor 13 , a transistor 14 (used as a driving transistor), a capacitor C1 , a capacitor C2 , and a LED 20 . In addition, in this example, C3 represents the inherent equivalent capacitance of the light emitting diode 20 itself. In addition, in this example, the capacitance value of the capacitor C2 is greater than the capacitance value of the capacitor C1, and the combined capacitance value of the capacitors C1 and C2 is equal to that electrically coupled to the control terminal and the source terminal of the driving transistor in the prior art. The equivalent capacitance between is the capacitance value Ct after the capacitance value is increased. The transistor 11 has a control terminal 110 , a first terminal 111 and a second terminal 112 . The control terminal 110 of the transistor 11 is electrically coupled to the control signal Scan, so that the transistor 11 is turned on or off by the control signal Scan. The first terminal 111 of the transistor 11 is used to receive the data signal Data, and the data signal Data can provide a data potential Vdata or a reference potential Vref to the first terminal 111 of the transistor 11 .

The transistor 12 has a control terminal 120 , a first terminal 121 , and a second terminal 122 . The control terminal 120 of the transistor 12 is electrically coupled to the control signal EM, so that the transistor 12 is turned on or off by the control signal EM. The first end 121 of the transistor 12 is electrically coupled to the operating power supply OVDD. The transistor 13 has a control terminal 130 , a first terminal 131 , and a second terminal 132 . The control terminal 130 of the transistor 13 is electrically coupled to the control signal Reset1, so that the transistor 13 is turned on or off by the control signal Reset1. The transistor 14 has a control terminal 140 , a first terminal 141 , and a second terminal 142 . The first terminal 141 of the transistor 14 is electrically coupled to the second terminal 122 of the transistor 12, and the second terminal 142 of the transistor 14 is electrically coupled to the second terminal 132 of the transistor 13, and the control terminal 140 of the transistor 14 is electrically coupled Coupled to the second terminal 112 of the transistor 11 .

The capacitor C1 has a first terminal C11 and a second terminal C12. The first terminal C11 of the capacitor C1 is electrically coupled to the control terminal 140 of the transistor 14 , and the second terminal C12 of the capacitor C1 is electrically coupled to the second terminal 142 of the transistor 14 and the second terminal 132 of the transistor 13 . The capacitor C2 has a first terminal C21 and a second terminal C22. The first terminal C21 of the capacitor C2 is electrically coupled to the second terminal 112 of the transistor 11 and the first terminal C11 of the capacitor C1 , and the second terminal C22 of the capacitor C2 is electrically coupled to the first terminal 131 of the transistor 13 . The LED 20 has a first end 201 and a second end 202 . The first terminal 201 of the LED 20 is electrically coupled to the second terminal 142 of the transistor 14 , and the second terminal 202 of the LED 20 is electrically coupled to the operating power supply OVSS.

FIG. 2 is a signal timing diagram of one of the LED pixel circuits shown in FIG. 1 . As shown in FIG. 2 , the light-emitting diode pixel circuit 100 in FIG. 1 can operate in sequence during the reset period, the compensation period, the data writing period, and the light-emitting period, wherein each signal can have a high level H and a low level L. In this state, when a high level H is applied to the gate of the N-type transistor, the N-type transistor can be turned on, but when a high level H is applied to the gate of the P-type transistor, the P-type transistor will be turned off; otherwise, When the low level L is applied to the gate of the N-type transistor, the N-type transistor will be turned off, and when the low level L is applied to the gate of the P-type transistor, the P-type transistor will be turned on. The high level H may be equal to the potential OVDDH, for example, and the low level L may be equal to the potential OVDDL, for example. Please refer to FIG. 1 and FIG. 2 together. The transistor 11 of the light-emitting diode pixel circuit 100 is used to conduct during the reset period, the compensation period, and the data writing period, and the first terminal 111 of the transistor 11 receives during the data writing period. The data potential Vdata provided by the data signal Data receives the reference potential Vref provided by the data signal Data during the reset period, the compensation period and the light emitting period. The transistor 12 is used to turn on during the reset period, the compensation period and the light-emitting period, and the first terminal 121 of the transistor 12 receives the potential OVDDL provided by the operating power supply OVDD during the reset period, and the first terminal 121 of the transistor 12 is in the reset period. The potential OVDDH provided by the operation power supply OVDD is received during the compensation period, the data writing period and the light emitting period, and the potential OVDDL is lower than the potential OVDDH. The transistor 13 is turned on during the reset period, the data writing period and the light emitting period. In particular, during the data writing period, the conduction times of the transistor 13 and the transistor 11 may partially overlap or not overlap (in FIG. 2 ), and the conduction time of the transistor 13 is later than that of the transistor 11. on-time. In addition, since the operating power supply OVDD provides the potential OVDDL during the reset period, the potential on the node S will be OVDDL. At this time, the capacitors C1 and C2 will discharge through the node S to reset the LED pixel circuit 100 .

Taking FIG. 2 as an example, in detail, when the LED pixel circuit 100 is operating in the reset period, the transistor 11, the transistor 12 and the transistor 13 will be turned on by the control signal Scan, the control signal EM and the control signal Reset1 respectively. , and at this time, the first terminal 111 of the transistor 11 receives the reference potential Vref provided by the data signal Data, and the first terminal 121 of the transistor 12 receives the potential OVDDL provided by the operating power supply OVDD, so the potential Vg of the node G at this time is ideally will be equal to Vref, and the potential Vs of node S will be equal to OVDDL under ideal conditions. Next, when the LED pixel circuit 100 is operating in the compensation period, the transistor 11 is still turned on, and the first terminal 111 of the transistor 11 continues to receive the reference potential Vref provided by the data signal Data, and the transistor 12 is still turned on. state, but the first terminal of the transistor 12 receives the potential OVDDH provided by the operating power supply OVDD at this time, and the transistor 13 is turned off during this period, so the potential Vg of the node G is still Vref at this time, and the potential of the node S The potential Vs will continue to rise from the level of the potential OVDDL to be equal to or substantially equal to Vref−Vth, wherein Vth is a threshold voltage (Threshold Voltage) of the transistor 14 . Since the combined capacitance of the capacitors C1 and C2 is equal to the capacitance Ct of the equivalent capacitance electrically coupled between the control terminal and the source terminal of the driving transistor in the aforementioned known technology after the capacitance value is increased, and here At this time, the entire LED pixel circuit 100 only needs to charge the capacitors C1 and C3 instead of the capacitor C2, so the speed of compensation can be accelerated.

Next, when the LED pixel circuit 100 is operating in the data writing period, the transistor 11 will be turned off after a preset time t1, and before the transistor 11 is turned off, the first terminal 111 of the transistor 11 will receive the data signal Data The provided data potential Vdata. In addition, during the data writing period, the transistor 12 will be turned off, and the transistor 13 will be turned on after the above-mentioned preset time t1 (for example, it will be turned on after entering the data writing period t2, that is, the transistor 13 and the transistor 11 The conduction time is non-overlapping), so the potential Vg of the node G at this time will be equal to Vdata under ideal conditions, and the potential of the node S will become Vref-Vth+a (Vdata-Vret) through capacitive coupling, because the node When G changes from the voltage level of Vref to the voltage level of Vdata, the transistor 13 is turned off, so a is C1/(C1+C3).

It can be seen from the above that since the capacitance value of the capacitor C1 is smaller than the capacitance value Ct of the equivalent capacitance originally electrically coupled between the control terminal and the source terminal of the driving transistor in the known technology after the capacitance value is increased, the light-emitting diode pixel circuit When the 100 self-compensation period enters the data writing period, the voltage coupled from the node G to the node S will decrease, thus increasing the voltage difference between the node G and the node S. In this way, the amount of current passing through the transistor 14 will increase, thereby increasing the light-emitting current flowing through the light-emitting diode 20 .

Finally, when the LED pixel circuit 100 is operating in the light-emitting period, the transistor 11 remains turned off, the transistors 12 and 13 remain turned on, and the transistor 12 continues to receive the potential OVDDH provided by the operating power supply OVDD. At this time, the potential change of node S will be coupled to node G, and the coupling amount can be calculated by the formula (C1+C2)/(C1+C2+Cp), where Cp (not shown) is related to node G the parasitic capacitance value. It can be seen from the above formula that since the sum of the capacitance values of the capacitors C1 and C2 is equal to the capacitance value Ct after the increase of the equivalent capacitance electrically coupled between the control terminal and the source terminal of the driving transistor in the aforementioned known technology, Therefore, such an approach can also reduce the parasitic capacitance effect.

In another example of the data writing period, the time when the control signal Scan transitions from high level (high) to low level (low) may be later than the time when the control signal Reset1 transitions from low level to high level , so that the conduction times of the transistor 13 and the transistor 11 are partially overlapped, thereby preventing the node G from changing due to being in a floating state due to the influence of the voltage coupled by the capacitors C1 and C2 during the transition process of the two control signals its level.

Of course, although in the embodiment shown in FIG. 1 , the capacitor C3 represents the inherent equivalent capacitance of the light emitting diode 20 itself, but in the case of insufficient capacitance value of the inherent equivalent capacitance of the light emitting diode 20 itself, the designer can freely A physical capacitor is connected in parallel next to the light emitting diode 20, so that the equivalent capacitance between the first end 201 and the second end 202 of the light emitting diode 20 can be the sum of the inherent equivalent capacitance of the light emitting diode 20 itself and the capacitance of the parallel capacitor. .

FIG. 3 is a circuit structure diagram of an LED pixel circuit according to another embodiment of the present invention. In FIG. 3, the same reference numerals as those in FIG. 1 represent the same components or signals. As shown in FIG. 3 , the circuit structure of the LED pixel circuit 200 is substantially the same as that of the LED pixel circuit 100 in FIG. 1 , the only difference being that the LED pixel circuit 200 further includes a transistor 15 . The transistor 15 has a control terminal 150, a first terminal 151 and a second terminal 152, and the control terminal 150 of the transistor 15 receives the control signal Reset2, and the first terminal 151 of the transistor 15 is electrically coupled to a preset potential Vsus (its potential magnitude same or approximately equal to the potential OVDDL), and the second terminal 152 of the transistor 15 is electrically coupled to the first terminal 131 of the transistor 13 .

FIG. 4 is a signal timing diagram of one of the LED pixel circuits shown in FIG. 3 . As shown in FIG. 4 , the LED pixel circuit 200 also operates in the reset period, the compensation period, the data writing period and the light emitting period in sequence. The transistor 11 in the LED pixel circuit 200 is used to conduct during the reset period, the compensation period and the data writing period, and the first terminal 111 of the transistor 11 receives the data provided by the data signal Data during the data writing period. potential Vdata, and receive the reference potential Vref provided by the data signal Data during the reset period, the compensation period and the light-emitting period. The transistor 12 in the LED pixel circuit 200 is turned on during the compensation period and the light-emitting period. The transistor 13 in the LED pixel circuit 200 is turned on during the reset period, the data writing period and the light emitting period. Wherein, during the data writing period, the turn-on time of the transistor 13 and the transistor 11 in the LED pixel circuit 200 can also be partially overlapped or not overlapped (in FIG. previously described), and the turn-on time of transistor 13 is later than the turn-on time of transistor 11 . The transistor 15 in the LED pixel circuit 200 is turned on during the reset period, and the first terminal 151 of the transistor 15 receives the preset potential Vsus during the reset period. The preset potential Vsus may have a potential OVDDL, for example. In addition, since the preset potential Vsus is provided to one terminal of the capacitor C1 and one terminal of the capacitor C2 during the reset period, the capacitors C1 and C2 are discharged to reset the LED pixel circuit 200 at this time.

Although in the previous description, the capacitor C1 , the capacitor C2 and the transistor 13 are all independent components, they can also be regarded as a capacitor module. The capacitance module is used to provide an equivalent capacitance between the control terminal 140 of the transistor 14 and the second terminal 142 of the transistor 14, and the equivalent capacitance provided by the capacitance module is during the reset period and the light-emitting period of the LED pixel circuit. The capacitance value of the capacitor is greater than the capacitance value of the equivalent capacitance provided when the LED pixel circuit is in the compensation period and the data writing period. Of course, the implementation of the above-mentioned capacitor module is only used as an example, and is not intended to limit the present invention.

FIG. 5 is a flow chart of a driving method of an LED pixel circuit according to an embodiment of the present invention. Through the above description, the driving method of the LED pixel circuit 100 can be summarized into steps 501 - 504 as shown in FIG. 5 .

Step 501 : During the reset period, make the operating power supply OVDD provide the potential OVDDL, turn on the transistor 11 , the transistor 12 and the transistor 13 , and provide the reference potential Vref to the first terminal 111 of the transistor 11 . Step 502: During the compensation period, make the operating power supply OVDD provide a potential OVDDH, the potential OVDDH is greater than the potential OVDDL, turn on the transistor 11 and the transistor 12, turn off the transistor 13, and provide the reference potential Vref to the first terminal 111 of the transistor 11. Step 503: During the data writing period, make the operating power supply OVDD provide a potential OVDDH, turn on the transistor 11 and the transistor 13, and turn off the transistor 12, wherein the turn-on time of the transistor 11 and the transistor 13 is partially overlapped or not overlapped, and The turn-on time of the transistor 11 is earlier than the turn-on time of the transistor 13 , and provides the data potential Vdata to the first terminal 111 of the transistor 11 when the transistor 11 is turned on. Step 504 : During the light-emitting period, make the operating power supply OVDD provide the potential OVDDH, turn off the transistor 11 , turn on the transistor 12 and the transistor 13 , and provide the reference potential Vref to the first terminal 111 of the transistor 11 . In the above steps 501-504, the reset period is prior to the compensation period, the compensation period is prior to the data writing period, and the data writing period is prior to the light emitting period.

FIG. 6 is a flow chart of a driving method of an LED pixel circuit according to an embodiment of the present invention. Through the above description, the driving method of the LED pixel circuit 200 can be summarized into steps 601 - 604 as shown in FIG. 6 .

Step 601 : During the reset period, turn on the transistor 11 , the transistor 13 and the transistor 15 , and provide the reference potential Vref to the first terminal 111 of the transistor 11 at the same time. Step 602 : During the compensation period, turn on the transistor 11 and the transistor 12 , turn off the transistor 13 and the transistor 15 at the same time, and provide the reference potential Vref to the first terminal 111 of the transistor 11 . Step 603: During the data writing period, turn on the transistor 11 and the transistor 13, and turn off the transistor 12 and the transistor 15, wherein the turn-on time of the transistor 11 and the transistor 13 is partially overlapped or non-overlapping, and the turn-on time of the transistor 11 The data potential Vdata is provided to the first terminal 111 of the transistor 11 prior to the turn-on time of the transistor 13 and when the transistor 11 is turned on. Step 604 : During the light-emitting period, turn off the transistor 11 and the transistor 15 , turn on the transistor 12 and the transistor 13 , and provide the reference potential Vref to the first terminal 111 of the transistor 11 . In the above steps 601-604, the reset period is prior to the compensation period, the compensation period is prior to the data writing period, and the data writing period is prior to the light emitting period.

To sum up, in the circuit structure of the light-emitting diode pixel circuit of the present invention, for example, a capacitor module composed of two capacitors and a transistor is used to electrically couple between the control terminal and the source terminal of the driving transistor, and Use this transistor to decide whether to make the above two capacitors electrically coupled between the control terminal and the source terminal of the drive transistor, or to allow only one of the capacitors to be electrically coupled between the control terminal and the source terminal of the drive transistor , so as to change the capacitance value of the equivalent capacitance electrically coupled between the control terminal and the source terminal of the driving transistor during different operation periods of the LED pixel circuit. Accordingly, as long as the transistor is turned on during the reset period and the light-emitting period so that the above-mentioned two capacitors are connected in parallel, and the transistor is turned off during the remaining two periods, then the light-emitting diode pixel circuit of the present invention can avoid the problem of the conventional technology. The light-emitting current of the light-emitting diode is reduced, and the compensation speed is slowed down.

Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, this The scope of protection of the invention shall prevail as defined by the appended claims.

Claims (11)

1. a light-emitting diode pixel circuit, including:

One the first transistor, has a control end, one first end and one second end, this first transistor This control end electric property coupling one first control signal, this first end of this first transistor is in order to receive one Data potential or a reference potential；

One transistor seconds, has a control end, one first end and one second end, this second crystal This control end electric property coupling one second control signal of pipe, this first end electric property coupling of this transistor seconds One first operation power supply；

One third transistor, has a control end, one first end and one second end, the 3rd crystal This control end electric property coupling 1 the 3rd control signal of pipe；

One the 4th transistor, has a control end, one first end and one second end, the 4th crystal This first end of pipe is electrically coupled to this second end of this transistor seconds, the 4th transistor this second End is electrically coupled to this second end of this third transistor, and this electrical coupling of control end of the 4th transistor It is connected to this second end of this first transistor；

One first electric capacity, has one first end and one second end, this electrical coupling of the first end of this first electric capacity Being connected to this control end of the 4th transistor, this second end of this first electric capacity should with the 4th transistor This common electric property coupling of the second end of second end and this third transistor；

One second electric capacity, has one first end and one second end, this first end of this second electric capacity with this This second end of one transistor and this common electric property coupling of the first end of this first electric capacity, this second electric capacity This second end is electrically coupled to this first end of this third transistor, and the capacitance of this second electric capacity is more than The capacitance of this first electric capacity；And

One light emitting diode, has one first end and one second end, this first end of this light emitting diode Being electrically coupled to this second end of the 4th transistor, this second end of this light emitting diode is electrically coupled to One second operation power supply；

During wherein this first transistor is used to a replacement, one compensate during and during a data address period Conducting, and this first end of this first transistor receives this data potential in this data address period, and in Receive this reference potential during this replacement, during this compensation and between a light emission period, this transistor seconds in order to Time during this replacement, during this compensation and during this luminescence turn on, and this transistor seconds this first Hold during this replacement, receive one first current potential that this first operation power supply is provided, and this transistor seconds This first end during this compensation, between this data address period and this light emission period, receive this first operation electricity One second current potential that source is provided, and this first current potential is less than this second current potential, this third transistor in order to Conducting time during this replacement, during this data address period and this luminescence, in this data address period In, the ON time of this third transistor and this first transistor for partly overlapping or the most overlapping, and this The ON time of three transistors is later than the ON time of this first transistor,

Wherein, during this replacement prior to this compensation during, prior to this data address period during this compensation, And during this data address period is prior to this luminescence.

2. light-emitting diode pixel circuit as claimed in claim 1, it has further included one the 3rd electric capacity, 3rd electric capacity has one first end and one second end, and this first end of the 3rd electric capacity is electrically coupled to this This first end of light emitting diode, this second end of the 3rd electric capacity is electrically coupled to this light emitting diode This second end.

3. a light-emitting diode pixel circuit, including:

One the first transistor, has a control end, one first end and one second end, this first transistor This control end electric property coupling one first control signal, this first end of this first transistor is in order to receive one Data potential or a reference potential；

One transistor seconds, has a control end, one first end and one second end, this second crystal This control end electric property coupling one second control signal of pipe, this first end electric property coupling of this transistor seconds One first operation power supply；

One third transistor, has a control end, one first end and one second end, the 3rd crystal This control end electric property coupling 1 the 3rd control signal of pipe；

One the 4th transistor, has a control end, one first end and one second end, the 4th crystal This first end of pipe is electrically coupled to this second end of this transistor seconds, the 4th transistor this second End is electrically coupled to this second end of this third transistor, and this electrical coupling of control end of the 4th transistor It is connected to this second end of this first transistor；

One first electric capacity, has one first end and one second end, this electrical coupling of the first end of this first electric capacity Being connected to this control end of the 4th transistor, this second end of this first electric capacity should with the 4th transistor This common electric property coupling of the second end of second end and this third transistor；

One second electric capacity, has one first end and one second end, this first end of this second electric capacity with this This second end of one transistor and this common electric property coupling of the first end of this first electric capacity, this second electric capacity This second end is electrically coupled to this first end of this third transistor, and the capacitance of this second electric capacity is more than The capacitance of this first electric capacity；And

One light emitting diode, has one first end and one second end, this first end of this light emitting diode Being electrically coupled to this second end of the 4th transistor, this second end of this light emitting diode is electrically coupled to One second operation power supply；And

One the 5th transistor, the 5th transistor has a control end, one first end and one second end, should This control end of 5th transistor receives one the 4th control signal, and this first end of the 5th transistor is electrical Couple a preset potential, this second end of the 5th transistor be electrically coupled to this third transistor this One end；

During wherein this first transistor is used to a replacement, one compensate during and during a data address period Conducting, and this first end of this first transistor receives this data potential in this data address period, and in Receive this reference potential during this replacement, during this compensation and between a light emission period, this transistor seconds in order to Turn on time during this compensation and during this luminescence, during this third transistor is used to this replacement, this number According to time during address period and this luminescence turn on, in this data address period, this third transistor and should The ON time of the first transistor is for partly overlapping or the most overlapping, and the ON time evening of this third transistor In the ON time of this first transistor, and conducting when the 5th transistor is used to during this replacement, And the 5th this first end of transistor during this replacement, receive this preset potential,

Wherein, during this replacement prior to this compensation during, prior to this data address period during this compensation, During this data address period is prior to this luminescence.

4. a light-emitting diode pixel circuit, including:

One the first transistor, has a control end, one first end and one second end, this first transistor This control end electric property coupling one first control signal, this first end of this first transistor is in order to receive one Data potential or a reference potential；

One transistor seconds, has a control end, one first end and one second end, this transistor seconds This control end electric property coupling one second control signal, this first end electric property coupling one of this transistor seconds First operation power supply；

One third transistor, has a control end, one first end and one second end, this third transistor This first end be electrically coupled to this second end of this transistor seconds, and this control of this third transistor End is electrically coupled to this second end of this first transistor；

One light emitting diode, has one first end and one second end, this first end of this light emitting diode Being electrically coupled to this second end of this third transistor, this second end of this light emitting diode is electrically coupled to One second operation power supply；And

One capacitance module, is electrically coupled between this control end of this third transistor and this second end, should Capacitance module in order to provide an equivalent capacity between this control end of this third transistor and this second end, and This capacitance module during this diode pixel circuit is in a replacement with a luminescence during time provided should The value of equivalent capacity more than this diode pixel circuit be in during a compensation with a data address periods time institute The value of this equivalent capacity provided.

5. light-emitting diode pixel circuit as claimed in claim 4, wherein this first transistor is used to One reset during, one compensate during and conducting during a data address period, and this first transistor this One end receives this data potential in this data address period, and during this replacement, during this compensation and one Receive this reference potential between light emission period, during this transistor seconds is used to this replacement, during this compensation and Turn on time during this luminescence, and this first end of this transistor seconds receives this first behaviour during this replacement Make one first current potential that power supply is provided, and this first end of this transistor seconds during this compensation, should One second current potential that this first operation power supply is provided is received between data address period and this light emission period, and should First current potential is less than this second current potential,

Wherein, during this replacement prior to this compensation during, prior to this data address period during this compensation, During this data address period is prior to this luminescence.

6. light-emitting diode pixel circuit as claimed in claim 4, wherein this capacitance module includes:

One the 4th transistor, has a control end, one first end and one second end, the 4th crystal This control end electric property coupling 1 the 3rd control signal of pipe；

One first electric capacity, has one first end and one second end, this electrical coupling of the first end of this first electric capacity Being connected to this control end of this third transistor, this second end of this first electric capacity should with this third transistor This common electric property coupling of the second end of second end and the 4th transistor；And

One second electric capacity, has one first end and one second end, this first end of this second electric capacity with this This second end of one transistor and this common electric property coupling of the first end of this first electric capacity, this second electric capacity This second end is electrically coupled to this first end of the 4th transistor, and the capacitance of this second electric capacity is more than The capacitance of this first electric capacity.

7. light-emitting diode pixel circuit as claimed in claim 6, wherein this first transistor is used to One reset during, one compensate during and conducting during a data address period, and this first transistor this One end receives this data potential in this data address period, and during this replacement, during this compensation and one Receive this reference potential between light emission period, during this transistor seconds is used to this replacement, during this compensation and Turn on time during this luminescence, and this first end of this transistor seconds receives this first behaviour during this replacement Make one first current potential that power supply is provided, and this first end of this transistor seconds during this compensation, should One second current potential that this first operation power supply is provided is received between data address period and this light emission period, and should First current potential be less than this second current potential, during the 4th transistor is used to this replacement, these data write the phase Between and this luminescence during time conducting, in this data address period, the 4th transistor and this first crystal The conducting of pipe is for partly overlapping or the most overlapping, and the ON time of the 4th transistor is later than this first crystal The ON time of pipe,

Wherein, during this replacement prior to this compensation during, prior to this data address period during this compensation, During this data address period is prior to this luminescence.

8. light-emitting diode pixel circuit as claimed in claim 6, it further includes one the 5th transistor, 5th transistor has a control end, one first end and one second end, this control of the 5th transistor End receives one the 4th control signal, this first end electric property coupling one preset potential of the 5th transistor, is somebody's turn to do This second end of 5th transistor is electrically coupled to this first end of the 4th transistor.

9. light-emitting diode pixel circuit as claimed in claim 8, wherein this first transistor is used to One reset during, one compensate during and conducting during a data address period, and this first transistor this One end receives this data potential in this data address period, and during this replacement, during this compensation and one This reference potential is received, time during this transistor seconds is used to this compensation and during this luminescence between light emission period Conducting, leads time during the 4th transistor is used to this replacement, during this data address period and this luminescence Logical, in this data address period, the ON time of the 4th transistor and this first transistor is part Overlapping or the most overlapping, and the ON time of the 4th transistor is later than the ON time of this first transistor, And conducting when being used to during this replacement of the 5th transistor, and this first end of the 5th transistor is in this This preset potential is received during replacement,

Wherein, during this replacement prior to this compensation during, prior to this data address period during this compensation, During this data address period is prior to this luminescence.

10. a driving method for light-emitting diode pixel circuit, in order to drive a kind of light emitting diode picture Element circuit, this light-emitting diode pixel circuit includes: a first transistor, have a control end, one the One end and one second end, this control end electric property coupling one first control signal of this first transistor, should This first end of the first transistor is in order to receive a data potential or a reference potential；One second crystal Pipe, has a control end, one first end and one second end, this control end electricity of this transistor seconds Property couple one second control signal, this first end electric property coupling one first of this transistor seconds operation electricity Source；One third transistor, has a control end, one first end and one second end, the 3rd crystal This control end electric property coupling 1 the 3rd control signal of pipe；One the 4th transistor, have a control end, one First end and one second end, this first end of the 4th transistor is electrically coupled to this transistor seconds This second end, this second end of the 4th transistor be electrically coupled to this third transistor this second End, and this control end of the 4th transistor is electrically coupled to this second end of this first transistor；One One electric capacity, has one first end and one second end, this first end of this first electric capacity be electrically coupled to this This control end of four transistors, this second end of this first electric capacity and this second end of the 4th transistor and This common electric property coupling of the second end of this third transistor；One second electric capacity, has one first end and one Two ends, this first end of this second electric capacity and this second end of this first transistor and this first electric capacity should The first common electric property coupling of end, this second end of this second electric capacity is electrically coupled to being somebody's turn to do of this third transistor First end, and the capacitance of this second electric capacity is more than the capacitance of this first electric capacity；And a light-emitting diodes Pipe, has one first end and one second end, this first end of this light emitting diode be electrically coupled to this This second end of four transistors, this second end of this light emitting diode is electrically coupled to one second operation electricity Source,

This driving method includes:

During one resets, make this first operation power supply provide one first current potential, and turn on this first crystalline substance Body pipe, this transistor seconds and this third transistor, provide a reference potential to this first transistor simultaneously This first end；

During one compensates, making this first operation power supply provide one second current potential, this second current potential is more than This first current potential, and turn on this first transistor and this transistor seconds, simultaneously close off the 3rd crystal Pipe, and provide this reference potential to this first end of this first transistor；

In a data address period, make this first operation power supply provide this second current potential, and turn on this This third transistor of one transistor AND gate, and close this transistor seconds, wherein this first transistor with should The ON time of third transistor is for partly overlapping or the most overlapping, and the ON time of this first transistor is first In the ON time of this third transistor, and provide a data potential to being somebody's turn to do when this first transistor turns on This first end of the first transistor；And

During a luminescence, make this first operation power supply provide this second current potential, and close this first crystalline substance Body pipe, and turn on this transistor seconds and this third transistor, and provide this reference potential to this first This first end of transistor,

Wherein, during this replacement prior to this compensation during, prior to this data address period during this compensation, During this data address period is prior to this luminescence.

The driving method of 11. 1 kinds of light-emitting diode pixel circuits, in order to drive a kind of light emitting diode picture Element circuit, this light-emitting diode pixel circuit includes: a first transistor, have a control end, one the One end and one second end, this control end electric property coupling one first control signal of this first transistor, should This first end of the first transistor is in order to receive a data potential or a reference potential；One second crystal Pipe, has a control end, one first end and one second end, this control end electricity of this transistor seconds Property couple one second control signal, this first end electric property coupling one first of this transistor seconds operation electricity Source；One third transistor, has a control end, one first end and one second end, the 3rd crystal This control end electric property coupling 1 the 3rd control signal of pipe；One the 4th transistor, have a control end, one First end and one second end, this first end of the 4th transistor is electrically coupled to this transistor seconds This second end, this second end of the 4th transistor be electrically coupled to this third transistor this second End, and this control end of the 4th transistor is electrically coupled to this second end of this first transistor；One One electric capacity, has one first end and one second end, this first end of this first electric capacity be electrically coupled to this This control end of four transistors, this second end of this first electric capacity and this second end of the 4th transistor and This common electric property coupling of the second end of this third transistor；One second electric capacity, has one first end and one Two ends, this first end of this second electric capacity and this second end of this first transistor and this first electric capacity should The first common electric property coupling of end, this second end of this second electric capacity is electrically coupled to being somebody's turn to do of this third transistor First end, and the capacitance of this second electric capacity is more than the capacitance of this first electric capacity；One light emitting diode, Having one first end and one second end, it is brilliant that this first end of this light emitting diode is electrically coupled to the 4th This second end of body pipe, this second end of this light emitting diode is electrically coupled to one second operation power supply；With And one the 5th transistor, the 5th transistor has a control end, one first end and one second end, and this is years old This control end of five transistors receives one the 4th control signal, this electrical coupling of the first end of the 5th transistor Connect a preset potential, this second end of the 5th transistor be electrically coupled to this third transistor this first End,

This driving method includes:

During one resets, turn on this first transistor, this third transistor and the 5th transistor, There is provided a reference potential to this first end of this first transistor simultaneously；

During one compensates, turn on this first transistor and this transistor seconds, simultaneously close off the 3rd Transistor AND gate the 5th transistor, and provide this reference potential to this first end of this first transistor；

In a data address period, turn on this first transistor and this third transistor, and closedown should Transistor seconds and the 5th transistor, wherein this first transistor and the ON time of this third transistor For partly overlapping or the most overlapping, and the ON time of this first transistor is prior to the conducting of this third transistor Time, and provide when this first transistor turns on a data potential to this first transistor this first End；And

During a luminescence, close this first transistor and the 5th transistor, and turn on this second crystalline substance Body pipe and this third transistor, and provide this reference potential to this first end of this first transistor,

Wherein, during this replacement prior to this compensation during, prior to this data address period during this compensation, During this data address period is prior to this luminescence.