WO2015051659A1

WO2015051659A1 - Pixel drive unit and drive method therefor, and pixel circuit

Info

Publication number: WO2015051659A1
Application number: PCT/CN2014/082407
Authority: WO
Inventors: 马占洁
Original assignee: 京东方科技集团股份有限公司
Priority date: 2013-10-08
Filing date: 2014-07-17
Publication date: 2015-04-16
Also published as: CN103489406A; CN103489406B

Abstract

A pixel drive unit and a drive method therefor, and a pixel circuit. The pixel drive unit comprises a plurality of pixel drive sub-units and light-emitting devices (R1, R2, R3), the pixel drive sub-units comprising compensation capacitors (C1, C2, C3) and switch transistors (M1, M2, M3), the compensation capacitors (C1, C2, C3) being used for charging and discharging under the control of the switch transistors (M1, M2, M3) so as to drive the light-emitting devices (R1, R2, R3). Unnecessary power loss is reduced, and at the same time, the overall power consumption of a panel is significantly reduced in the same light-emitting state.

Description

Pixel driving unit and driving method thereof, pixel circuit

The present disclosure relates to a pixel driving unit, a driving method thereof, and a pixel circuit. Background technique

Currently, an active-mode Active Matrix Organic Light Emitting Diode (AMOLED) display device has a panel power consumption mainly related to a signal source voltage of an IC signal output and an organic light-emitting diode (Organic Light-Emitting Diode). , abbreviated as OLED) for current correlation. In a certain brightness, the current flowing through the organic light emitting diode is mainly related to the organic electroluminescent material and the device structure, and can be improved by optimizing the organic electroluminescent material and the device structure, thereby reducing the power consumption of the AMOLED display panel. Most of the current known methods in the art are using such methods for panel power reduction.

At the same time, the signal source voltage is reduced by reducing the path resistance of the signal source to the organic light emitting diode, thereby reducing the power consumption of the display panel.

In the design of the active matrix organic light emitting diode display device, the cathode end and the anode end of all the pixels are respectively connected to each other, that is, the anode end potentials of all the pixels are the same, and the signals of the cathode ends of all the pixels are the same; thus the output end of the IC driving circuit Only one anode signal and one cathode signal can be output. In the conventional structure, the anode signal and the cathode signal output from the IC are directly input to the pixel electrode. Reducing the signal source voltage by reducing the path resistance of the signal source to the OLED is relatively limited.

The present disclosure provides a pixel driving unit capable of minimizing a signal source voltage and thereby reducing power consumption of a display panel, a driving method thereof, and a pixel circuit. Summary of the invention

At least one embodiment of the present invention is to solve the problem of high power consumption of an existing active matrix organic light emitting diode display panel.

At least one embodiment of the present invention provides a pixel driving unit including a plurality of pixel driving sub-units and a light emitting device, each of the pixel driving sub-units including a compensation capacitor and a switching transistor, The compensation capacitor is charged under control of the switching transistor to drive the light emitting device.

Further, the first end of the compensation capacitor is connected to the signal source voltage, the second end is connected to the drain of the switching transistor and the anode end of the light emitting device, and the source of the switching transistor is connected to the reference voltage, the gate and the scan Signal line connection.

Further, the switching transistor is a P-type field effect transistor or an N-type field effect transistor. Further, the light emitting device is an organic electroluminescent diode.

At least one embodiment of the present invention also provides a driving method of the above pixel driving unit, comprising the following steps:

In the reset phase of the signal source voltage output low potential and the reference voltage output high potential, the switching transistor is turned on by the scan signal line, and the reference potential is applied to the second end of the compensation capacitor by the reference voltage; the signal source voltage outputs a high potential, The light-emitting phase of the reference voltage output low potential, the switching transistor is turned off by the scan signal line, and the working potential is applied to the first end of the compensation capacitor by the signal source voltage; the charge is discharged from the compensation capacitor to the anode terminal of the light-emitting device, The light emitting device emits light.

Further, the driving method includes a plurality of reset phases and a plurality of light emitting phases, and the reset phase and the light emitting phase alternate.

Further, the driving method may include only one reset phase.

Further, the switching transistor is a P-type field effect transistor; in the reset phase, the scanning signal line outputs a low potential for turning on the switching transistor; in the light emitting phase, the scanning signal line outputs a high potential for The switching transistor is turned off.

Further, the switching transistor is an N-type field effect transistor; in the reset phase, the scanning signal line outputs a high potential for turning on the switching transistor; in the light emitting phase, the scanning signal line outputs a low potential for The switching transistor is turned off.

At least one embodiment of the present invention, further provides a pixel circuit, comprising the pixel driving unit according to any one of the preceding claims, further comprising a timing control module, wherein the timing control module is connected to the scanning signal line, and is used for automatically scanning each signal line Timing switching control.

At least one embodiment of the present invention can obtain an advantage: before the signal source voltage is input to the anode terminal of each of the light emitting devices, a capacitor unit is provided, which realizes an electric potential input to the anode end of the light emitting device according to the organic electroluminescent material and Different anode lengths are obtained by different structures, which reduces unnecessary power loss. At the same time, in the same lighting state, the overall power consumption of the panel is greatly reduced due to the relatively low potential of the signal source. DRAWINGS

1 is a schematic diagram showing the circuit connection of a pixel driving unit according to an embodiment of the present invention;

2 is a timing control diagram of a driving method of a pixel driving unit according to a first embodiment of the present invention;

3 is a timing control diagram of a driving method of a pixel driving unit according to a second embodiment of the present invention;

4 is a timing control diagram of a driving method of a pixel driving unit according to a third embodiment of the present invention;

Fig. 5 is a timing chart showing the driving method of the pixel driving unit of the fourth embodiment of the present invention. Detailed ways

The specific embodiments of the present invention are further described in detail below with reference to the drawings and embodiments. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

Embodiments of the present invention provide a pixel driving unit including a plurality of pixel driving subunits and a light emitting device, wherein each of the pixel driving subunits includes a compensation capacitor and a switching transistor, and the compensation capacitor is charged under the control of the switching transistor. For driving the light emitting device.

For example, the pixel driving subunit includes a compensation capacitor and a switching transistor, the first end of the compensation capacitor is connected to a signal source voltage, and the second end is connected to a drain of the switching transistor and an anode terminal of the light emitting device, and the switching transistor The source is connected to the reference voltage, and the gate is connected to the scan signal line.

1 is a schematic diagram showing the circuit connection of a pixel driving unit according to an embodiment of the present invention. It should be noted that the pixel driving unit shown in FIG. 1 includes three pixel driving sub-units for driving the red sub-pixel, the green sub-pixel and the blue sub-pixel, respectively. Of course, for other structure pixel structures, the pixel driving unit There may be a plurality of, for example, four pixel driving sub-units, which are used for driving the red sub-pixel, the green sub-pixel, the blue sub-pixel, and the yellow sub-pixel, respectively, and the like, which is not limited by the present invention.

As shown in FIG. 1, the first pixel driving subunit includes a first compensation capacitor C1 and a first switching transistor M1, and the first end of the first compensation capacitor C1 (ie, the upper end of the first compensation capacitor C1 as shown) Connected to the signal source voltage VDD, the second end (ie, the lower end of the first compensation capacitor C1 as shown) and the drain of the first switching transistor M1 (ie, the right end of the first switching transistor M1 as shown) And connecting the anode end of the first light emitting device R1, the source of the first switching transistor M1 (ie, the left end of the first switching transistor M1 as shown) is connected to the reference voltage Vref, the gate of the first switching transistor M1 (ie, the lower end of the first switching transistor M1 as shown) and the first scanning signal line Switch R connection;

The second pixel driving subunit includes a second compensation capacitor C2 and a second switching transistor M2, the first end of the second compensation capacitor C2 (ie, the upper end of the second compensation capacitor C2 as shown) and the signal source voltage VDD Connected, the second end (ie, the lower end of the second compensation capacitor C2 as shown) and the drain of the second switching transistor M2 (ie, the right end of the second switching transistor M2 as shown) and the second light emitting device The anode terminal of R2 is connected, the source of the second switching transistor M2 (ie, the left end of the second switching transistor M2 as shown) is connected to the reference voltage Vref, and the gate of the second switching transistor M2 (ie, as shown in the figure) a lower end of the second switching transistor M2 is connected to the second scanning signal line Switch G;

The third pixel driving subunit includes a third compensation capacitor C3 and a third switching transistor M3, the first end of the third compensation capacitor C3 (ie, the upper end of the third compensation capacitor C3 as shown) and the signal source voltage VDD Connected, the second end (ie, the lower end of the third compensation capacitor C3 as shown) and the drain of the third switching transistor M3 (ie, the right end of the third switching transistor M3 as shown) and the third light emitting device The anode terminal of R3 is connected, the source of the third switching transistor M3 (ie, the lower end of the third switching transistor M3 as shown) is connected to the reference voltage Vref, and the gate of the third switching transistor M3 (ie, as shown in the figure) The lower end of the third switching transistor M3 is connected to the third scanning signal line Switch B.

The first light emitting device R1, the second light emitting device R2, and the third light emitting device R3 are all organic electroluminescent diodes. The first scan signal line Switch R, the second scan signal line Switch G, and the third scan signal line Switch B are used to control the opening and closing of the first switching transistor M1, the second switching transistor M2, and the third switching transistor M3.

The first switching transistor M1, the second switching transistor M2, and the third switching transistor M3 in the pixel driving unit of the present invention may be a P-type field effect transistor or an N-type field effect transistor. It should be noted that, generally, the switching transistor has the same type as the organic EL LED display panel gate driving circuit and other transistors for driving the light emitting device, so that the manufacturing process can be simplified. Of course, the types of the switching transistors can also be different. These inventions are not limited.

The present invention also provides a driving method of a pixel driving unit. Embodiment 1 and Embodiment 2 describe the implementation of the present invention by taking a P-type field effect transistor as a switching transistor of a pixel driving unit. The driving method of the pixel driving unit of the example.

In the embodiment of the present invention, before the signal source voltage is input to the anode end of each of the light emitting devices, a capacitor unit is added, and the potential input to the anode end of the light emitting device is different according to the organic electroluminescent material and the structure. The extreme potential reduces the unnecessary power loss. At the same time, in the same lighting state, the overall power consumption of the panel is greatly reduced due to the relatively low potential of the signal source.

Embodiment 1

2 is a driving method of a pixel driving unit according to an embodiment of the present invention. The driving method includes a plurality of reset phases and a plurality of light emitting phases, wherein the reset phase and the light emitting phase are alternately performed, wherein the reset phase is T1 and the light emitting phase is Τ2.

In the reset phase T1, the signal source voltage VDD is a low voltage signal, the reference voltage Vref is a high potential signal, and the signals on the first scan signal line Switch R, the second scan signal line Switch G, and the third scan signal line Switch B are low-voltage. signal. Referring to FIG. 1, the reference voltage Vref charges the first compensation capacitor C1 through the first switching transistor M1, the second compensation capacitor C2 through the second switching transistor M2, and the third compensation capacitor C3 through the third switching transistor M3. .

For example, the timing resets the first compensation capacitor C1, the second compensation capacitor C2, and the third compensation capacitor C3 before each frame of the image. In the reset phase, the signal source voltage VDD is a low voltage signal, and the signals on the first scan signal line Switch R, the second scan signal line Switch G, and the third scan signal line Switch B are low voltage turn-on signals, and the reference voltage Vref is high. a signal (Vgh) that causes the second terminal potential of the first compensation capacitor C1, the second compensation capacitor C2, and the third compensation capacitor C3 to be charged to the Vgh potential; due to the organic electroluminescent material and device structure to the first light emitting device R1, The luminous efficiency of the two light-emitting devices R2 and the third light-emitting device R3 is different, and the voltage difference between the first light-emitting device R1, the second light-emitting device R2, and the third light-emitting device R3 is different, so that the adjustment can be The potential of the first scanning signal line Switch R, the second scanning signal line Switch G and the third scanning signal line Switch B corresponding to the light-emitting device R1, the second light-emitting device R2 and the third light-emitting device R3, so that the control The first switching transistor M1, the second switching transistor M2, and the third switching transistor M3 of a light emitting device R1, a second light emitting device R2, and a third light emitting device R3 are written with reference power When VGH, to achieve different charging rates to achieve a first compensation capacitor Cl, the different potential of the second compensation capacitor C2 and the third compensation capacitor C3 of the second end. At a first end of the first compensation capacitor C1, the second compensation capacitor C2, and the third compensation capacitor C3, the low potential signal of the signal source voltage VDD is Vgl, and the total amount of capacitance of the first light-emitting device R1 is written. The total amount of capacitance of the capacitor (Vgh_R-Vgl) x CI, written to the second light-emitting device R2 is (Vgh_G-Vgl) x C2, and the total amount of capacitance written to the third light-emitting device R3 is (Vgh- B-Vgl) C3, wherein Vgh_R is a high potential signal of the first light emitting device R1, Vgh_G is a high potential signal of the second light emitting device R2, and Vgh_B is a high potential signal of the third light emitting device R3.

After the end of the reset phase T1, the illumination phase T2 is the same as the normal display phase, the source voltage

VDD is a high voltage signal, and the timing control module T-con controls the first scan signal line Switch R, the second scan signal line Switch G, and the third scan signal line Switch B to turn off the first switching transistor M1, the second switching transistor M2, and the first The third switching transistor M3, the first compensation capacitor C1 discharges the first light emitting device R1 to emit light, the second compensation capacitor C2 discharges the second light emitting device R2 to emit light, and the third compensation capacitor C3 discharges the third light emitting device R3 to emit light.

For example, as shown in FIG. 2, in the light-emitting phase T2, the signal source voltage VDD becomes a high potential (Vgh), and at this time, the first scan signal line Switch R, the second scan signal line Switch G, and the third scan signal line Switch B The upper potential is in a high potential phase, so that the first switching transistor M1, the second switching transistor M2, and the third switching transistor M3 are turned off. At this time, the signal source voltage VDD loads the operating voltage high potential Vgh to the first compensation capacitor C1, The first end of the second compensation capacitor C2 and the third compensation capacitor C3, according to the principle of constant capacitance charge, the potential of the second end of the first compensation capacitor C1 corresponding to the first light-emitting device R1 is Vgh+Vgh_R-Vgl, The potential of the second end of the second compensation capacitor C2 corresponding to the second light-emitting device R2 is Vgh+Vgh_G-Vgl, and the potential of the second end of the third compensation capacitor C3 corresponding to the third light-emitting device R3 is Vgh+Vgh_B-Vgl, The potentials input to the anode ends of the first light emitting device R1, the second light emitting device R2, and the third light emitting device R3 are based on the materials of the first light emitting device R1, the second light emitting device R2, and the third light emitting device R3. Different configuration, the male terminal get different potential losses reduce unnecessary power consumption, while at the same light emission state, the signal source due to the relatively low potential, such that the panel greatly reduced overall power consumption.

When the next frame image is displayed, the above-described reset phase T1 and the light-emitting phase T2 are also repeated. Embodiment 2

As shown in FIG. 3, the driving method of the pixel driving unit in this embodiment is the same as that of the first embodiment. The content disclosed in the first embodiment also belongs to the content disclosed in the second embodiment. The difference between the first embodiment is that: the reset only occurs in the reset phase T1 before the image of the first frame, that is, the capacitance reset is performed only when the first frame image is displayed, so that the display screen is more stable between each frame of the image, and does not appear. Defects such as flickering. In the embodiment of the present invention, before the signal source voltage is input to the anode end of each of the light emitting devices, a capacitor unit is added, and the potential input to the anode end of the light emitting device is different according to the organic electroluminescent material and the structure. The extreme potential reduces the unnecessary power loss. At the same time, in the same lighting state, the overall power consumption of the panel is greatly reduced due to the relatively low potential of the signal source.

In the following Embodiments 3 and 4, the driving method of the pixel driving unit in the embodiment of the present invention is described by taking the switching transistors constituting the pixel driving unit as N-type field effect transistors as an example.

Embodiment 3

As shown in FIG. 4, the method for driving the pixel driving unit in this embodiment is the same as that of the first embodiment. The content disclosed in the first embodiment also belongs to the content disclosed in this embodiment. This embodiment and the first embodiment The difference is that: in the reset phase T1, the potentials on the first scan signal line Switch R, the second scan signal line Switch G, and the third scan signal line Switch B are at a high potential, so that the N-type first switching transistor M1, the first The second switching transistor M2 and the third switching transistor M3 are turned on, the reference voltage Vref charges the first compensation capacitor C1 through the first switching transistor M1, and the second compensation capacitor C2 is charged through the second switching transistor M2, through the third switching transistor M3 The third compensation capacitor C3 is charged.

After the end of the reset phase T1, the light-emitting phase T2 is the same as the normal display phase, and the potentials on the first scan signal line Switch R, the second scan signal line Switch G, and the third scan signal line Switch B are low, so that the first switch The transistor M1, the second switching transistor M2, and the third switching transistor M3 are turned off. According to the principle of the constant charge, the potential of the second end of the first compensation capacitor C1 corresponding to the first light-emitting device R1 is Vgh+Vgh_R-Vgl, The potential of the second end of the second compensation capacitor C2 corresponding to the second illuminating device R2 is Vgh+Vgh_G-Vgl, and the potential of the second end of the third compensating capacitor C3 corresponding to the third illuminating device R3 is Vgh+Vgh_B-Vgl, Thereby, the potentials input to the anode ends of the first light emitting device R1, the second light emitting device R2, and the third light emitting device R3 are realized according to the materials and structures of the first light emitting device R1, the second light emitting device R2, and the third light emitting device R3. Different, and get different anode terminal potentials, reducing unnecessary power loss, and at the same time, in the same lighting state, because the signal source potential is relatively low, the panel is completely Significantly reducing power consumption.

When the next frame image is displayed, the above-described reset phase T1 and the light-emitting phase T2 are also repeated. Embodiment 4

As shown in FIG. 5, the technical content of the pixel driving unit driving method in this embodiment is the same as that of the third embodiment. The content disclosed in the third embodiment also belongs to the content disclosed in the fourth embodiment. The difference between the embodiment and the third embodiment is that: the reset only occurs in the reset phase T1 before the first frame image, that is, the capacitance reset is performed only when the first frame image is displayed, so that the display screen is more stable between each frame image, There will be a display failure such as flicker.

Embodiment 5

The fifth embodiment provides a pixel circuit, including a plurality of pixel driving units, and the pixel driving unit may be any one of the above embodiments, and the same technical content is not repeatedly described. The content disclosed in the fifth embodiment.

The pixel circuit of the fifth embodiment further includes a timing control module T-con, and the timing control module T-con is connected to the first scan signal line Switch R, the second scan signal line Switch G and the third scan signal line Switch B, and is used for Automatic timing switching control of the first scanning signal line Switch R, the second scanning signal line Switch G, and the third scanning signal line Switch B.

The embodiment of the invention further provides an organic light emitting diode backplane, which uses the pixel driving unit, the driving method and the pixel circuit described in the above embodiments, wherein the light emitting device is an organic electroluminescent diode.

In summary, the embodiment of the present invention realizes the potential input to the anode end of the light emitting device according to the organic electroluminescent material and structure by inputting a capacitor unit before the signal source voltage is input to the anode end of each of the light emitting devices. Different anode end potentials are obtained, which reduces unnecessary power loss. At the same time, in the same lighting state, the overall power consumption of the panel is greatly reduced due to the relatively low potential of the signal source.

The above is only a few alternative embodiments of the present invention, and it should be noted that those skilled in the art can make several improvements and modifications without departing from the principles of the present invention. And variations are also considered to be within the scope of the invention.

The present application claims the priority of the Chinese Patent Application No. 201310464199.9 filed on Oct. 8, 2013, the entire disclosure of which is hereby incorporated by reference.

Claims

Claim

A pixel driving unit, wherein the pixel driving unit includes a plurality of pixel driving subunits and a light emitting device, the pixel driving subunit includes a compensation capacitor and a switching transistor, and the compensation capacitor is used to charge under the control of the switching transistor Discharge to drive the light emitting device.

2. The pixel driving unit according to claim 1, wherein:

The first end of the compensation capacitor is connected to the signal source voltage, the second end is connected to the drain of the switching transistor and the anode end of the light emitting device, the source of the switching transistor is connected to the reference voltage, and the gate is connected to the scan signal line. .

The pixel driving unit according to any one of claims 1 to 2, wherein: the switching transistor is a P-type field effect transistor or an N-type field effect transistor.

The pixel driving unit according to any one of claims 1 to 3, wherein: the illuminating device is an organic electroluminescent diode.

The method of driving a pixel driving unit according to any one of claims 1 to 4, wherein the method comprises the following steps:

6. The driving method of a pixel driving unit according to claim 5, wherein: the method comprises a plurality of reset phases and a plurality of light emitting phases, wherein the reset phase and the light emitting phase alternate.

7. The driving method of a pixel driving unit according to claim 5, wherein: the method comprises a reset phase.

The driving method of the pixel driving unit according to any one of claims 5-7, wherein the switching transistor is a P-type field effect transistor; in a reset phase, the scanning signal line outputs a low potential for Turning on the switching transistor; in the illuminating phase, the scanning signal line outputs a high potential for turning off the switching transistor.

The driving method of the pixel driving unit according to any one of claims 5 to 7, wherein the switching transistor is an N-type field effect transistor; in the reset phase, the scanning signal line output is high a potential for turning on the switching transistor; in the illuminating phase, the scanning signal line outputs a low potential for turning off the switching transistor.

A pixel circuit, wherein the pixel circuit comprises a plurality of pixel driving units according to any one of claims 1 to 4, further comprising a timing control module, wherein the timing control module is connected to the scanning signal line, Automatic timing switching control of each scanning signal line.