PIXEL DRIVING CIRCUIT OF ACTIVE MATRIX ORGANIC LIGHT EMITTING DISPLAY DEVICE AND DRIVING METHOD OF ACTIVE MATRIX ORGANIC LIGHT EMITTING DISPLAY DEVICE

Provided are a pixel driving circuit of an AMOLED device and a pixel driving method of an AMOLED device. The pixel driving circuit comprises: sub pixel circuits, scan lines, data lines and control lines. Each sub pixel circuit comprises a first TFT, a second TFT, a third TFT, a capacitor and an OLED. In a blank display stage of each frame of the AMOLED device, the plurality of rows of control lines respectively input corresponding control signals to control the third TFTs in at least one row of sub pixel circuits to be turned on, and the plurality of columns of data lines inputs bias voltages, wherein the bias voltages are smaller than the power source negative voltage so that an anode voltage of OLED in the sub pixel circuit, in which the third TFT is turned on, is smaller than a cathode voltage to achieve reverse bias.

FIELD OF THE INVENTION

The present invention relates to a display field, and more particularly to a pixel driving circuit of an active matrix organic light emitting display device and a driving method of an active matrix organic light emitting display device.

BACKGROUND OF THE INVENTION

The Organic Light Emitting Display (OLED) possesses many outstanding properties of self-illumination, low driving voltage, high luminescence efficiency, short response time, high clarity and contrast, near 180° view angle, wide range of working temperature, applicability of flexible display and large scale full color display. The OLED is considered as the most potential display device.

The OLED can be categorized into two major types according to the driving methods, which are the Passive Matrix OLED (PMOLED) and the Active Matrix OLED (AMOLED), i.e. two types of the direct addressing and the Thin Film Transistor (TFT) matrix addressing. The AMOLED comprises pixels arranged in array and belongs to active display type, which has high lighting efficiency and is generally utilized for the large scale display devices of high resolution.

The AMOLED is a current driving element. When the electrical current flows through the organic light emitting diode, the organic light emitting diode emits light, and the brightness is determined according to the current flowing through the organic light emitting diode itself. Most of the present Integrated Circuits (IC) only transmit voltage signals. Therefore, the AMOLED pixel driving circuit needs to accomplish the task of converting the voltage signals into the current signals. The traditional AMOLED pixel driving circuit generally is 2T1C, which is a structure comprising two thin film transistors and one capacitor to convert the voltage into the current.

As shown inFIG. 1, which is a 2T1C pixel driving circuit employed for AMOLED, comprising a first thin film transistor T10, a second thin film transistor T20, a capacitor C10and an organic light emitting diode D10. The first thin film transistor T10is a switch thin film transistor, and the second thin film transistor T20is a drive thin film transistor, and the capacitor C10is a storage capacitor. Specifically, a gate of the first thin film transistor T10receives a scan signal Gate. A source of the first thin film transistor receives a data signal Data. A drain of the first thin film transistor is electrically coupled to a gate of the second thin film transistor T20and one end of the capacitor C10. A source of the second thin film transistor T20receives a power source positive voltage OVDD. A drain of the second thin film transistor is electrically coupled to an anode of the organic light emitting diode D10. A cathode of the organic light emitting diode D10receives a power source negative voltage OVSS. The one end of the capacitor C10is electrically coupled to the drain of the first thin film transistor T10, and the other end is electrically coupled to the source of the second thin film transistor T20. As displaying, the scan signal Gate controls the first thin film transistor T10to be activated, and the data signal Data enters the gate of the second thin film transistor T20and the capacitor C10via the first thin film transistor T10. Then, the first thin film transistor T10is deactivated. With the storage function of the capacitor C10, the gate voltage of the second thin film transistor T20can remain to hold the data signal voltage to make the second thin film transistor T20to be in the conducted state to drive the current to enter the organic light emitting diode D10via the second thin film transistor T20and to drive the organic light emitting diode D10to emit light.

During operation of the pixel driving circuit shown inFIG. 1, the organic light emitting diode D10is in a direct current bias state for a long time, and the internal ion polarity thereof forms a built-in electric field, which causes the threshold voltage of the organic light emitting diode D10to continuously increase and makes the brightness gradually decrease. Meanwhile, the long time emission also shortens the life of the organic light emitting diode D10, and the problem of uniform image display caused by the different aging degrees of the organic light emitting diodes in different sub pixels may also occur to affect the display result.

SUMMARY OF THE INVENTION

An objective of the present invention is to provide a pixel driving circuit of an active matrix organic light emitting display device, which can slow down the aging of organic light emitting diodes, extend the life of organic light emitting diodes and improve the display quality.

Another objective of the present invention is to provide a pixel driving method of an active matrix organic light emitting display device, which can slow down the aging of organic light emitting diodes, extend the life of organic light emitting diodes and improve the display quality.

For realizing the aforesaid objectives, the present invention first provides a pixel driving circuit of an active matrix organic light emitting display device, comprising: a plurality of sub pixel circuits arranged in an array, a plurality of rows of scan lines, a plurality of columns of data lines and a plurality of rows of control lines;

wherein each row of sub pixel circuits is correspondingly coupled to one row of scan lines and one row of control lines, and each column of sub pixel circuits is correspondingly coupled to one column of data lines.

each sub pixel circuit comprises a first thin film transistor, a second thin film transistor, a third thin film transistor, a capacitor and an organic light emitting diode; a gate of the first thin film transistor is electrically coupled to a corresponding scan line, a source of the first thin film transistor is electrically to a corresponding data line, and a drain of the first thin film transistor is electrically to a gate of the second thin film transistor; a source of the second thin film transistor receives a power source positive voltage, and a drain of the second thin film transistor is electrically to an anode of the organic light emitting diode; two ends of the capacitor are respectively coupled to the gate and the source of the second thin film transistor; a cathode of the organic light emitting diode receives a power source negative voltage; a gate of the third thin film transistor is electrically to a corresponding control line, a source of the third thin film transistor is electrically to a corresponding data line, and a drain of the third thin film transistor is electrically to the anode of the organic light emitting diode;

in a blank display stage of each frame of the active matrix organic light emitting display device, the plurality of rows of control lines respectively input corresponding control signals to control the third thin film transistors in at least one row of sub pixel circuits to be turned on, and the plurality of columns of data lines inputs bias voltages, wherein the bias voltages are smaller than the power source negative voltage.

The control signals inputted by the plurality of rows of control lines are pulse signals, and pulses of the control signals inputted by two adjacent control lines are sequentially generated, a phase difference between the pulses of the control signals inputted by the two adjacent control lines is one frame duration of the active matrix organic light emitting display device, a period of the control signal inputted by each control line is a product of the one frame duration of the active matrix organic light emitting display device and a number of rows of the sub pixel circuits.

in the blank display stage of each frame of the active matrix organic light emitting display device, the plurality of rows of control lines respectively input corresponding control signals to control the third thin film transistors in one row of sub pixel circuits to be turned on, and to control third thin film transistors in all sub pixel circuits except the row of sub pixel circuits to be turned off;

in an effective display stage of each frame of the active matrix organic light emitting display device, the plurality of rows of control lines respectively input corresponding control signals to control the third thin film transistors in all sub pixel circuits to be turned off.

In a blank display stage of a (m×M+n)th frame of the active matrix organic light emitting display device, the plurality of rows of control lines respectively input corresponding control signals to control the third thin film transistors in a nth row of sub pixel circuits to be turned on, and to control third thin film transistors in sub pixel circuits except the nth row of sub pixel circuits to be turned off, wherein M is a number of rows of the sub pixel circuits, m is a non-negative integer and n is a positive integer.

The third thin film transistor is an N-type thin film transistor.

In an effective display stage of each frame of the active matrix organic light emitting display device, the plurality of rows of scan lines sequentially input scan signals to control the first thin film transistors in the plurality of rows of sub pixel circuits to be sequentially turned on, and the plurality of columns of data lines input corresponding data signals for the active matrix organic light emitting display device to show images.

In the blank display stage of each frame of the active matrix organic light emitting display device, the plurality of rows of scan lines controls the first thin film transistors in all sub pixel circuits to be off.

The first thin film transistor is an N-type thin film transistor, and the second thin film transistor is a P-type thin film transistor.

The pixel driving circuit of the active matrix organic light emitting display device further comprises a control circuit electrically coupled to the plurality of rows of control lines, and the control signals inputted to the plurality of rows of control lines are provided by the control circuit.

The present invention further provides a pixel driving method of the active matrix organic light emitting display device, applied to the aforesaid pixel driving circuit of the active matrix organic light emitting display device, comprising:

Step S1, entering an effective display stage of a (m×M+n)th frame, wherein the plurality of rows of control lines inputs corresponding control signals to control the third thin film transistors in all sub pixel circuits to be turned off, and the plurality of rows of scan lines sequentially inputs scan signals to control the first thin film transistors in the plurality of rows of sub pixel circuits to be sequentially turned on, and the plurality of columns of data lines inputs the data signals corresponding to the (m×M+n)th frame for the active matrix organic light emitting display device to show the (m×M+n)th frame, wherein M is a number of rows of the sub pixel circuit, m is a non-negative integer and n is a positive integer;

Step S2, entering a blank display stage of the (m×M+n)th frame, wherein the plurality of rows of scan lines controls the first thin film transistors in all sub pixel circuits to be turned off, and an nth row of control lines inputs corresponding control signals to control the third thin film transistors in an nth row of sub pixel circuits to be turned on, and the control lines except the nth row of control lines input corresponding control signals to control the third thin film transistors in the sub pixel circuits except the nth row of sub pixel circuits to be turned off, and the plurality of columns of data lines inputs the bias voltages;

Step S3, entering an effective display stage of a (m×M+n+1)th frame, wherein the plurality of rows of control lines inputs corresponding control signals to control the third thin film transistors in all sub pixel circuits to be turned off, and the plurality of rows of scan lines sequentially inputs scan signals to control the first thin film transistors in the plurality of rows of sub pixel circuits to be sequentially turned on, and the plurality of columns of data lines inputs the data signals corresponding to the (m×M+n+1)th frame for the active matrix organic light emitting display device to show the (m×M+n+1)th frame;

Step S4, entering a blank display stage of the (m×M+n+1)th frame, wherein the plurality of rows of scan lines controls the first thin film transistors in all sub pixel circuits to be turned off, and an n+1th row of control lines inputs corresponding control signals to control the third thin film transistors in an n+1th row of sub pixel circuits to be turned on, and the control lines except the n+1th row of control lines input corresponding control signals to control the third thin film transistors in the sub pixel circuits except the n+1th row of sub pixel circuits to be turned off, and the plurality of columns of data lines inputs the bias voltages.

The present invention further provides a pixel driving circuit of an active matrix organic light emitting display device, comprising: a plurality of sub pixel circuits arranged in an array, a plurality of rows of scan lines, a plurality of columns of data lines and a plurality of rows of control lines;

wherein each row of sub pixel circuits is correspondingly coupled to one row of scan lines and one row of control lines, and each column of sub pixel circuits is correspondingly coupled to one column of data lines;

each sub pixel circuit comprises a first thin film transistor, a second thin film transistor, a third thin film transistor, a capacitor and an organic light emitting diode; a gate of the first thin film transistor is electrically coupled to a corresponding scan line, a source of the first thin film transistor is electrically to a corresponding data line, and a drain of the first thin film transistor is electrically to a gate of the second thin film transistor; a source of the second thin film transistor receives a power source positive voltage, and a drain of the second thin film transistor is electrically to an anode of the organic light emitting diode; two ends of the capacitor are respectively coupled to the gate and the source of the second thin film transistor; a cathode of the organic light emitting diode receives a power source negative voltage; a gate of the third thin film transistor is electrically to a corresponding control line, a source of the third thin film transistor is electrically to a corresponding data line, and a drain of the third thin film transistor is electrically to the anode of the organic light emitting diode;

in a blank display stage of each frame of the active matrix organic light emitting display device, the plurality of rows of control lines respectively input corresponding control signals to control the third thin film transistors in at least one row of sub pixel circuits to be turned on, and the plurality of columns of data lines inputs bias voltages, wherein the bias voltages are smaller than the power source negative voltage;

wherein the control signals inputted by the plurality of rows of control lines are pulse signals, and pulses of the control signals inputted by two adjacent control lines are sequentially generated, a phase difference between the pulses of the control signals inputted by the two adjacent control lines is one frame duration of the active matrix organic light emitting display device, a period of the control signal inputted by each control line is a product of the one frame duration of the active matrix organic light emitting display device and a number of rows of the sub pixel circuits;

in the blank display stage of each frame of the active matrix organic light emitting display device, the plurality of rows of control lines respectively input corresponding control signals to control the third thin film transistors in one row of sub pixel circuits to be turned on, and to control third thin film transistors in all sub pixel circuits except the row of sub pixel circuits to be turned off;

in an effective display stage of each frame of the active matrix organic light emitting display device, the plurality of rows of control lines respectively input corresponding control signals to control the third thin film transistors in all sub pixel circuits to be turned off;

wherein in a blank display stage of a (m×M+n)th frame of the active matrix organic light emitting display device, the plurality of rows of control lines respectively input corresponding control signals to control the third thin film transistors in a nth row of sub pixel circuits to be turned on, and to control third thin film transistors in sub pixel circuits except the nth row of sub pixel circuits to be turned off, wherein M is a number of rows of the sub pixel circuits, m is a non-negative integer and n is a positive integer;

wherein the third thin film transistor is an N-type thin film transistor;

wherein in an effective display stage of each frame of the active matrix organic light emitting display device, the plurality of rows of scan lines sequentially input scan signals to control the first thin film transistors in the plurality of rows of sub pixel circuits to be sequentially turned on, and the plurality of columns of data lines input corresponding data signals for the active matrix organic light emitting display device to show images.

The benefits of the present invention are: the pixel driving circuit of the AMOLED device provided by the present invention comprises: sub pixel circuits, scan lines, data lines and control lines. Each sub pixel circuit comprises a first TFT, a second TFT, a third TFT, a capacitor and an OLED. In a blank display stage of each frame of the AMOLED device, the plurality of rows of control lines respectively input corresponding control signals to control the third TFTs in at least one row of sub pixel circuits to be turned on, and the plurality of columns of data lines inputs bias voltages, wherein the bias voltages are smaller than the power source negative voltage so that an anode voltage of OLED in the sub pixel circuit, in which the third TFT is turned on, is smaller than a cathode voltage to achieve reverse bias. The aging of the OLED can be effectively reduced to prolong the life of the OLED and to improve display quality. The pixel driving method of the active matrix organic light emitting display device according to the present invention can effectively slow down the aging of organic light emitting diodes, extend the life of organic light emitting diodes and improve the display quality.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Please refer toFIG. 2. The present invention first provides a pixel driving circuit of an active matrix organic light emitting display device, comprising: a plurality of sub pixel circuits10arranged in an array, a plurality of rows of scan lines20, a plurality of columns of data lines30, a plurality of rows of control lines40and a control circuit50.

Each row of sub pixel circuits10is correspondingly coupled to one row of scan lines20and one row of control lines40, and each column of sub pixel circuits10is correspondingly coupled to one column of data lines30, and the control circuit50is electrically coupled to the plurality of rows of control lines40to input control signals to the plurality of rows of control lines40.

Each sub pixel circuit10comprises a first thin film transistor T1, a second thin film transistor T2, a third thin film transistor T3, a capacitor C1and an organic light emitting diode D1; a gate of the first thin film transistor T1is electrically coupled to a corresponding scan line20, a source of the first thin film transistor is electrically to a corresponding data line30, and a drain of the first thin film transistor is electrically to a gate of the second thin film transistor T2; a source of the second thin film transistor T2receives a power source positive voltage OVDD, and a drain of the second thin film transistor is electrically to an anode of the organic light emitting diode D1; two ends of the capacitor C1are respectively coupled to the gate and the source of the second thin film transistor T2; a cathode of the organic light emitting diode D1receives a power source negative voltage OVSS; a gate of the third thin film transistor T3is electrically to a corresponding control line40, a source of the third thin film transistor is electrically to a corresponding data line30, and a drain of the third thin film transistor is electrically to the anode of the organic light emitting diode D1.

Significantly, in a blank display stage of each frame of the active matrix organic light emitting display device, the plurality of rows of control lines40respectively input corresponding control signals to control the third thin film transistors T3in at least one row of sub pixel circuits10to be turned on, and the plurality of columns of data lines30inputs bias voltages, wherein the bias voltages are smaller than the power source negative voltage OVSS.

Specifically, as shown inFIG. 2, the control signals inputted by the plurality of rows of control lines40are pulse signals, and pulses of the control signals inputted by two adjacent control lines40are sequentially generated, a phase difference between the pulses of the control signals inputted by the two adjacent control lines40is one frame duration of the active matrix organic light emitting display device, a period of the control signal inputted by each control line40is a product of the one frame duration of the active matrix organic light emitting display device and a number of rows of the sub pixel circuits10. In a blank display stage of each frame of the active matrix organic light emitting display device, the plurality of rows of control lines40respectively input corresponding control signals to control the third thin film transistors T3in one row of sub pixel circuits10to be turned on, and to control third thin film transistors T3in all sub pixel circuits10except the row of sub pixel circuits10to be turned off. In an effective display stage of each frame of the active matrix organic light emitting display device, the plurality of rows of control lines40respectively input corresponding control signals to control the third thin film transistors T3in all sub pixel circuits10to be turned off.

Preferably, in a blank display stage of a (m×M+n)th frame of the active matrix organic light emitting display device, the plurality of rows of control lines40respectively input corresponding control signals to control the third thin film transistors T3in a nth row of sub pixel circuits10to be turned on, and to control third thin film transistors T3in sub pixel circuits10except the nth row of sub pixel circuits10to be turned off, wherein M is a number of rows of the sub pixel circuits10, m is a non-negative integer and n is a positive integer.

Specifically, the third thin film transistor T3may be an N-type thin film transistor or a P-type thin film transistor. In the embodiment shown inFIG. 2, the third thin film transistor T3is an N-type thin film transistor.

Specifically, in an effective display stage of each frame of the active matrix organic light emitting display device, the plurality of rows of scan lines20sequentially input scan signals to control the first thin film transistors T1in the plurality of rows of sub pixel circuits10to be sequentially turned on, and the plurality of columns of data lines30input corresponding data signals for the active matrix organic light emitting display device to show images. In the blank display stage of each frame of the active matrix organic light emitting display device, the plurality of rows of scan lines20controls the first thin film transistors T1in all sub pixel circuits10to be off.

Specifically, the first thin film transistor T1may be an N-type thin film transistor and the second thin film transistor T2may be a P-type thin film transistor.

The embodiments shown inFIG. 2andFIG. 3are illustrated. The working process of the pixel driving circuit of the AMOLED display device of the present invention is described:

first, entering an effective display stage of a (m×M+n)th frame, wherein the plurality of rows of control lines40input control signals of low potential to control the third thin film transistors T3in all sub pixel circuits10to be turned off, and the plurality of rows of scan lines20sequentially input scan signals of high potential to control the first thin film transistors T1in the plurality of rows of sub pixel circuits10to be sequentially turned on, and the plurality of columns of data lines30input the data signals corresponding to the (m×M+n)th frame for the active matrix organic light emitting display device to normally show the (m×M+n)th frame.

Then, entering a blank display stage of the (m×M+n)th frame, wherein the plurality of rows of scan lines20controls the first thin film transistors T1in all sub pixel circuits10to be turned off, and an nth row of control lines GM(n) inputs control signals of high potential to control the third thin film transistors T3in an nth row of sub pixel circuits10to be turned on, and the control lines40except the nth row of control lines GM(n) input control signals of low potential to control the third thin film transistors T3in the sub pixel circuits10except the nth row of sub pixel circuits10to be turned off, and the plurality of columns of data lines30inputs the bias voltages, and then the bias voltages lower than the power source negative voltage OVSS is written into the anodes of the organic light emitting diodes D1in the nth row of sub pixel circuits10through the third thin film transistors T3, which are turned on, and the cathodes of the organic light emitting diodes D1in the nth row of sub pixel circuits10receives the power source negative voltage OVSS. Namely, in the blank display stage of the (m×M+n)th frame, a voltage difference of the anode and the cathode of the organic light emitting diode D1in the nth row of sub pixel circuits10is a negative value to be in a reverse bias state for reducing the aging of the organic light emitting diodes D1in the nth row of sub pixel circuits10.

After that, entering an effective display stage of a (m×M+n+1)th frame, wherein the plurality of rows of control lines40inputs control signals of low potential to control the third thin film transistors T3in all sub pixel circuits10to be turned off, and the plurality of rows of scan lines20sequentially inputs scan signals of high potential to control the first thin film transistors T1in the plurality of rows of sub pixel circuits10to be sequentially turned on, and the plurality of columns of data lines30inputs the data signals corresponding to the (m×M+n+1)th frame for the active matrix organic light emitting display device to normally show the (m×M+n+1)th frame.

Subsequently, entering a blank display stage of the (m×M+n+1)th frame, wherein the plurality of rows of scan lines20are at low potential and controls the first thin film transistors T1in all sub pixel circuits10to be turned off, and an n+1th row of control lines GM(n+1) inputs control signals of high potential to control the third thin film transistors T3in an n+1th row of sub pixel circuits10to be turned on, and the control lines40except the n+1th row of control lines GM(n+1) input control signals of low potential to control the third thin film transistors T3in the sub pixel circuits10except the n+1th row of sub pixel circuits10to be turned off, and the plurality of columns of data lines30inputs the bias voltages, and then the bias voltages lower than the power source negative voltage OVSS is written into the anodes of the organic light emitting diodes D1in the n+1th row of sub pixel circuits10through the third thin film transistors T3, which are turned on, and the cathodes of the organic light emitting diodes D1in the n+1th row of sub pixel circuits10receives the power source negative voltage OVSS. Namely, in the blank display stage of the (m×M+n+)th frame, a voltage difference of the anode and the cathode of the organic light emitting diode D1in the n+1th row of sub pixel circuits10is a negative value to be in a reverse bias state for reducing the aging of the organic light emitting diodes D1in the n+1th row of sub pixel circuits10.

After repeating the above steps, after a duration of M frames, the organic light emitting diodes D1in the plurality of rows of sub pixel circuits10are all reverse biased once. In case that the number of rows of the sub pixel circuits10is 2160, and the refresh frequency is 60 Hz, i.e. the duration of one frame is 16.6 ms, the time interval between two reverse biases of the organic light emitting diodes D1in the same row of sub pixel circuits10is 2160×16.6 ms=35.86 s.

Specifically, in the pixel driving circuit of the AMOLED device according to the present invention, by coupling the source to the corresponding data line30, coupling the gate to the corresponding control line40, and coupling the drain to the third thin film transistor T3corresponding to the anode of the organic light emitting diode D1in each sub pixel circuit10, and by controlling the third thin film transistor T3in at least one row of sub pixel circuits10to be turned on such that the bias voltage is written into the anode of the organic light emitting diode D1to achieve the reverse bias thereof in the blank display stage of one frame of the AMOLED device, the aging of the OLED can be effectively reduced to prolong the life of the OLED and to improve display quality. Meanwhile, the present invention utilizes the data line30of inputting the data signal to implement writing the bias voltage to the anode of the organic light emitting diode D1without adding additional voltage input line to simplify the structure of the AMOLED device and to promote the aperture ratio of the AMOLED device. Moreover, the bias voltage can be provided by a source driver chip of providing data signals. The number of source driver chips may be consistent with that of prior art, and the parasitic capacitance in the AMOLED may be effectively reduced.

Please refer toFIG. 4, combined withFIG. 2andFIG. 3. On the basis of the same inventive idea, the present invention further provides a pixel driving method of the active matrix organic light emitting display device, applied to the aforesaid pixel driving circuit of the active matrix organic light emitting display device, comprising:

Step S1, entering an effective display stage of a (m×M+n)th frame, wherein the plurality of rows of control lines40input corresponding control signals to control the third thin film transistors T3in all sub pixel circuits10to be turned off, and the plurality of rows of scan lines20sequentially inputs scan signals to control the first thin film transistors T1in the plurality of rows of sub pixel circuits10to be sequentially turned on, and the plurality of columns of data lines30inputs the data signals corresponding to the (m×M+n)th frame for the active matrix organic light emitting display device to show the (m×M+n)th frame, wherein M is a number of rows of the sub pixel circuit10, m is a non-negative integer and n is a positive integer.

Specifically, in Step S1of the embodiment shown inFIG. 2andFIG. 3, the plurality of rows of control lines40input control signals of low potential to control the third thin film transistors T3in all sub pixel circuits10to be turned off, and the plurality of rows of scan lines20sequentially input scan signals of high potential to control the first thin film transistors T1in the plurality of rows of sub pixel circuits10to be sequentially turned on, and the plurality of columns of data lines30input the data signals corresponding to the (m×M+n)th frame for the active matrix organic light emitting display device to normally show the (m×M+n)th frame.

Step S2, entering a blank display stage of the (m×M+n)th frame, wherein the plurality of rows of scan lines20controls the first thin film transistors T1in all sub pixel circuits20to be turned off, and an nth row of control lines GM(n) inputs corresponding control signals to control the third thin film transistors T3in an nth row of sub pixel circuits10to be turned on, and the control lines40except the nth row of control lines GM(n) input corresponding control signals to control the third thin film transistors T3in the sub pixel circuits10except the nth row of sub pixel circuits10to be turned off, and the plurality of columns of data lines30inputs the bias voltages.

Specifically, in Step S2of the embodiment shown inFIG. 2andFIG. 3, the plurality of rows of scan lines20controls the first thin film transistors T1in all sub pixel circuits10to be turned off, and an nth row of control lines GM(n) inputs control signals of high potential to control the third thin film transistors T3in an nth row of sub pixel circuits10to be turned on, and the control lines40except the nth row of control lines GM(n) input control signals of low potential to control the third thin film transistors T3in the sub pixel circuits10except the nth row of sub pixel circuits10to be turned off, and the plurality of columns of data lines30inputs the bias voltages, and then the bias voltages lower than the power source negative voltage OVSS is written into the anodes of the organic light emitting diodes D1in the nth row of sub pixel circuits10through the third thin film transistors T3, which are turned on, and the cathodes of the organic light emitting diodes D1in the nth row of sub pixel circuits10receives the power source negative voltage OVSS. Namely, in the blank display stage of the (m×M+n)th frame, a voltage difference of the anode and the cathode of the organic light emitting diode D1in the nth row of sub pixel circuits10is a negative value to be in a reverse bias state for reducing the aging of the organic light emitting diodes D1in the nth row of sub pixel circuits10.

Step S3, entering an effective display stage of a (m×M+n+1)th frame, wherein the plurality of rows of control lines40inputs corresponding control signals to control the third thin film transistors T3in all sub pixel circuits10to be turned off, and the plurality of rows of scan lines20sequentially inputs scan signals to control the first thin film transistors T1in the plurality of rows of sub pixel circuits10to be sequentially turned on, and the plurality of columns of data lines30inputs the data signals corresponding to the (m×M+n+1)th frame for the active matrix organic light emitting display device to show the (m×M+n+1)th frame.

Specifically, in Step S3of the embodiment shown inFIG. 2andFIG. 3, the plurality of rows of control lines40inputs control signals of low potential to control the third thin film transistors T3in all sub pixel circuits10to be turned off, and the plurality of rows of scan lines20sequentially inputs scan signals of high potential to control the first thin film transistors T1in the plurality of rows of sub pixel circuits10to be sequentially turned on, and the plurality of columns of data lines30inputs the data signals corresponding to the (m×M+n+1)th frame for the active matrix organic light emitting display device to normally show the (m×M+n+1)th frame.

Step S4, entering a blank display stage of the (m×M+n+1)th frame, wherein the plurality of rows of scan lines20controls the first thin film transistors T1in all sub pixel circuits10to be turned off, and an n+1th row of control lines GM(n+1) inputs corresponding control signals to control the third thin film transistors T3in an n+1th row of sub pixel circuits10to be turned on, and the control lines40except the n+1th row of control lines GM(n+1) input corresponding control signals to control the third thin film transistors T3in the sub pixel circuits10except the n+1th row of sub pixel circuits10to be turned off, and the plurality of columns of data lines30inputs the bias voltages.

Specifically, in Step S4of the embodiment shown inFIG. 2andFIG. 3, the plurality of rows of scan lines20are at low potential and controls the first thin film transistors T1in all sub pixel circuits10to be turned off, and an n+1th row of control lines GM(n+1) inputs control signals of high potential to control the third thin film transistors T3in an n+1th row of sub pixel circuits10to be turned on, and the control lines40except the n+1th row of control lines GM(n+1) input control signals of low potential to control the third thin film transistors T3in the sub pixel circuits10except the n+1th row of sub pixel circuits10to be turned off, and the plurality of columns of data lines30inputs the bias voltages, and then the bias voltages lower than the power source negative voltage OVSS is written into the anodes of the organic light emitting diodes D1in the n+1th row of sub pixel circuits10through the third thin film transistors T3, which are turned on, and the cathodes of the organic light emitting diodes D1in the n+1th row of sub pixel circuits10receives the power source negative voltage OVSS. Namely, in the blank display stage of the (m×M+n+1)th frame, a voltage difference of the anode and the cathode of the organic light emitting diode D1in the n+1th row of sub pixel circuits10is a negative value to be in a reverse bias state for reducing the aging of the organic light emitting diodes D1in the n+1th row of sub pixel circuits10.

After repeating the above steps, after a duration of M frames, the organic light emitting diodes D1in the plurality of rows of sub pixel circuits10are all reverse biased once. In case that the number of rows of the sub pixel circuits10is 2160, and the refresh frequency is 60 Hz, i.e. the duration of one frame is 16.6 ms, the time interval between two reverse biases of the organic light emitting diodes D1in the same row of sub pixel circuits10is 2160×16.6 ms=35.86 s.

Specifically, in the pixel driving method of the AMOLED device according to the present invention, by coupling the source to the corresponding data line30, coupling the gate to the corresponding control line40, and coupling the drain to the third thin film transistor T3corresponding to the anode of the organic light emitting diode D1in each sub pixel circuit10, and by controlling the third thin film transistor T3in at least one row of sub pixel circuits10to be turned on such that the bias voltage is written into the anode of the organic light emitting diode D1to achieve the reverse bias thereof in the blank display stage of one frame of the AMOLED device, the aging of the OLED can be effectively reduced to prolong the life of the OLED and to improve display quality. Meanwhile, the present invention utilizes the data line30of inputting the data signal to implement writing the bias voltage to the anode of the organic light emitting diode D1without adding additional voltage input line to simplify the structure of the AMOLED device and to promote the aperture ratio of the AMOLED device. Moreover, the bias voltage can be provided by a source driver chip of providing data signals. The number of source driver chips may be consistent with that of prior art, and the parasitic capacitance in the AMOLED may be effectively reduced.

In conclusion, the pixel driving circuit of the AMOLED device provided by the present invention comprises: sub pixel circuits, scan lines, data lines and control lines. Each sub pixel circuit comprises a first TFT, a second TFT, a third TFT, a capacitor and an OLED. In a blank display stage of each frame of the AMOLED device, the plurality of rows of control lines respectively input corresponding control signals to control the third TFTs in at least one row of sub pixel circuits to be turned on, and the plurality of columns of data lines inputs bias voltages, wherein the bias voltages are smaller than the power source negative voltage so that an anode voltage of OLED in the sub pixel circuit, in which the third TFT is turned on, is smaller than a cathode voltage to achieve reverse bias. The aging of the OLED can be effectively reduced to prolong the life of the OLED and to improve display quality. The pixel driving method of the active matrix organic light emitting display device according to the present invention can effectively slow down the aging of organic light emitting diodes, extend the life of organic light emitting diodes and improve the display quality.