CN117594004A - Display device and driving method thereof - Google Patents

Display device and driving method thereof Download PDF

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Publication number
CN117594004A
CN117594004A CN202311836910.9A CN202311836910A CN117594004A CN 117594004 A CN117594004 A CN 117594004A CN 202311836910 A CN202311836910 A CN 202311836910A CN 117594004 A CN117594004 A CN 117594004A
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China
Prior art keywords
switch
line
voltage
compensation
driving
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Granted
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CN202311836910.9A
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Chinese (zh)
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CN117594004B (en
Inventor
袁鑫
陈晨
周秀峰
谢俊烽
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HKC Co Ltd
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HKC Co Ltd
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Priority to CN202311836910.9A priority Critical patent/CN117594004B/en
Priority claimed from CN202311836910.9A external-priority patent/CN117594004B/en
Publication of CN117594004A publication Critical patent/CN117594004A/en
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    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
    • G09G3/30—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels
    • G09G3/32—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
    • G09G3/3208—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED]
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
    • G09G3/30—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels
    • G09G3/32—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
    • G09G3/3208—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED]
    • G09G3/3225—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2330/00—Aspects of power supply; Aspects of display protection and defect management
    • G09G2330/02—Details of power systems and of start or stop of display operation
    • G09G2330/021—Power management, e.g. power saving
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2330/00—Aspects of power supply; Aspects of display protection and defect management
    • G09G2330/08—Fault-tolerant or redundant circuits, or circuits in which repair of defects is prepared

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)
  • Control Of El Displays (AREA)

Abstract

The application discloses display device and a driving method thereof, wherein the display device comprises an organic light-emitting display panel and a compensation circuit, the organic light-emitting display panel is provided with a plurality of pixels, each pixel comprises a first scanning line, a second scanning line, a third scanning line, a first data line, a sensing line, a light-emitting unit, a first switch, a second switch, a driving switch and a repairing switch, a source electrode of the repairing switch is connected with a low-voltage source, a drain electrode of the repairing switch is connected with an output end of the first switch, a top grid electrode of the repairing switch is connected with the third scanning line, and a bottom grid electrode of the repairing switch is connected with the sensing line. Through the design, when the third scanning line is started, the repair switch can input lower voltage to the grid electrode of the drive switch, so that the drive switch is in a negative bias state, the problem of degradation of the repair drive switch caused by continuous positive bias during long-time use is solved, and the energy consumption of the drive chip is prevented from being increased.

Description

Display device and driving method thereof
Technical Field
The present disclosure relates to the field of display technologies, and in particular, to a display device and a driving method thereof.
Background
An organic light emitting diode (Organic Light Emitting Diode, OLED) is a current-type light emitting device that can emit light autonomously. In the organic light emitting display panel, the pixel circuit may drive the organic light emitting diode light emitting unit to emit light by setting the driving switch. However, the magnitude of the driving current flowing through the OLED is related to the threshold voltage Vth of the driving switch, so that in order to avoid the problem that the magnitude of the current flowing through the OLED is different due to Vth drift, it is generally required to compensate Vth during driving.
The compensation method in the related art may include an internal compensation and an external compensation, wherein the internal compensation is a compensation for achieving Vth by adding new thin film transistors and signal lines internally in the pixel circuit; the external compensation is to detect the voltage of the light emitting unit by an integrated circuit (Integrated Circuit, IC) chip outside the panel and adjust the voltage of the data signal according to the detected voltage to realize the compensation for Vth.
Since the drive switch is in the on state for a long time, the characteristic degradation characteristic curve thereof is continuously biased forward, and the threshold voltage value is continuously increased. When the threshold voltage value is detected and compensated into the data voltage, the data voltage after compensation is continuously increased along with the deterioration of the driving switch, so that the power consumption of the driving chip is improved.
Disclosure of Invention
The purpose of the present application is to provide a display device and a driving method thereof, which can compensate the threshold voltage of a driving switch in a pixel, and simultaneously repair the degradation problem of the driving switch, so as to avoid the increase of the power consumption of a driving chip.
The application discloses a display device, which comprises an organic light-emitting display panel and a compensation circuit, wherein the organic light-emitting display panel is provided with a plurality of pixels, and the compensation circuit is connected with the organic light-emitting display panel and is used for compensating the threshold voltage of a driving switch in the pixels; the pixel comprises a first scanning line, a second scanning line, a third scanning line, a first data line, a sensing line, a light emitting unit, a first switch, a second switch, a driving switch and a repairing switch, wherein the input end of the first switch is connected with the first data line, and the control end of the first switch is connected with the first scanning line; the input end of the driving switch is connected with a power line, the control end of the driving switch is connected with the output end of the first switch, and the output end of the driving switch is used for providing working voltage for the light-emitting unit; the input end of the second switch is connected with the output end of the driving switch, the control end of the second switch is connected with the second scanning line, and the output end of the second switch is connected with the sensing line; the source electrode of the repair switch is connected with a low-voltage source, the drain electrode of the repair switch is connected with the output end of the first switch, the top grid electrode of the repair switch is connected with the third scanning line, and the bottom grid electrode of the repair switch is connected with the sensing line; the compensation circuit comprises a compensation module, a first compensation switch and a second compensation switch, wherein the sensing line is connected with the reference voltage line through the first compensation switch, one end of the compensation module is connected with the sensing line through the second compensation switch, and the other end of the compensation module is connected with the first data line.
Optionally, the first data line and the sensing line are arranged in the same layer, the first scanning line, the second scanning line and the third scanning line are arranged in the same layer, and the sensing line is located between the third scanning line and the substrate of the organic light emitting display panel.
Optionally, the repair switch comprises an N-type four-terminal thin film transistor.
Optionally, the compensation module includes a calculation conversion unit, a storage unit and a compensation unit, where the calculation conversion unit is connected with the sensing line through the second compensation switch, and calculates a compensation value of the driving switch according to a sensing voltage on the sensing line; the storage unit is connected with the calculation conversion unit and is used for storing the compensation value; the compensation unit is connected with the storage unit, receives voltage data, and outputs the voltage data and the compensation value to the first data line.
The application also discloses a driving method of the display device, which is used for driving the display device, and the driving method comprises the following steps:
the initial stage: starting a first scanning line, starting a first switch and a first compensation switch, enabling the first switch to output data voltage, and enabling a sensing line to be connected with reference voltage;
sensing phase: opening a second scanning line, and opening a second switch to enable the voltage on the sensing line to rise until the voltage on the sensing line is equal to the difference value between the data voltage and the threshold voltage of the driving switch;
and (3) compensation: opening a second compensation switch, detecting the voltage on the sensing line to obtain sensing voltage, calculating a compensation value of the driving switch according to the sensing voltage by a compensation module, and compensating the driving switch;
and (3) a repairing stage: when the threshold voltage of the driving switch is larger than a preset value, a third scanning line is started, and a repairing switch is opened, so that the gate source voltage of the driving switch is smaller than zero.
Optionally, the preset value is 2V.
Optionally, the display period of the organic light emitting display panel includes a display stage and a non-display stage, the non-display stage includes a power-on non-display stage and a power-off non-display stage, the initial stage, the sensing stage and the compensation stage are located in the power-on non-display stage, and the repair stage is located in the power-off non-display stage.
Optionally, in the repairing phase, when the threshold voltage of the driving switch in one pixel is greater than a preset value, the third scanning lines in all pixels are turned on simultaneously, and the repairing switches in all pixels are turned on, so that the gate-source voltage of the driving switch in all pixels is less than zero.
Optionally, the third scan line in all pixels is connected to the same control line.
Optionally, in the repairing stage, the on time of the second scan line is shorter than the on time of the third scan line.
The beneficial effects of this application are: the method and the device not only can compensate the threshold voltage of the driving switch in the pixel through the compensation circuit, but also can avoid the problem of picture display caused by drift of the threshold voltage of the driving switch due to factors such as manufacturing process or aging; moreover, this application is still through addding third scanning line and repair switch in the pixel, and repair switch has four link, the source electrode is connected with low voltage source, the drain electrode is connected with the output of first switch, top grid is connected with third scanning line, bottom grid is connected with the sensing line, when third scanning line was opened, repair switch can be to the lower voltage of gate input of drive switch for drive switch is in the negative bias state, reaches repair drive switch and because long-time use appear the degradation problem that continuous forward bias led to, thereby avoided drive chip's energy consumption to increase.
Drawings
The accompanying drawings, which are included to provide a further understanding of the embodiments of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application. It is obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained from these drawings without inventive faculty for a person skilled in the art. In the drawings:
fig. 1 is a schematic diagram of a driving switching characteristic degradation trend curve;
fig. 2 is a schematic circuit diagram of a display device according to an embodiment of the present application;
FIG. 3 is a schematic diagram of a transfer characteristic of a repair switch;
fig. 4 is a flowchart of a driving method of a display device according to an embodiment of the present application;
FIG. 5 is a timing diagram of a pixel driving according to an embodiment of the present disclosure;
FIG. 6 is a schematic diagram of a display process provided by an embodiment of the present application;
fig. 7 is a schematic diagram of a driving switch according to an embodiment of the present application during degradation and repair.
10, a display device; 100. a pixel; t1 a first switch; t2, a second switch; DT and a driving switch; cst, storage capacitor; scan1, first Scan line; scan2, second Scan line; scan3, third Scan line; data, a first Data line; sen, sense line; t3, repairing the switch; 200. a compensation circuit; 210. a compensation module; SW1, a first compensation switch; SW2, a second compensation switch; 211. a calculation conversion unit; 212. a storage unit; 213. and a compensation unit.
Detailed Description
It should be understood that the terminology, specific structural and functional details disclosed herein are merely representative for purposes of describing particular embodiments, but that the application may be embodied in many alternate forms and should not be construed as limited to only the embodiments set forth herein.
Furthermore, unless expressly specified and limited otherwise, "connected" and "coupled" are to be construed broadly, and may be either permanently connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; either directly or indirectly through intermediaries, or in communication with each other. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art as the case may be.
Fig. 1 is a schematic diagram of a degradation trend curve of a driving switch characteristic, in which, as shown in fig. 1, the abscissa represents a gate-source voltage (Vgs) of the driving switch, the ordinate represents a source-drain current (Ids) of the driving switch, Δv1 and Δv2 represent degradation degrees of the driving switch, respectively, and Δv2 is greater than Δv1. As can be seen from the graph, as the driving switch is in the on state for a long time, the characteristic curve is continuously forward biased, the threshold voltage is continuously increased, and when the threshold voltage is detected and compensated into the data voltage, as the degradation of the driving switch is increased, the compensated data voltage is continuously increased, on one hand, the data voltage is caused to exceed the regulation range of the data driving chip, so that the capacity and the power consumption of the data driving chip need to be improved; on the other hand, the gate-source bias voltage is increased when the driving switch is operated, and the degradation speed of the driving switch is further increased.
Based on this, the present application provides a display device to solve this problem. As shown in fig. 2, the embodiment of the present application provides a display device 10, where the display device 10 includes an organic light emitting display panel and a compensation circuit 200, the organic light emitting display panel includes a plurality of pixels 100, and the compensation circuit 200 is connected to the organic light emitting display panel and is used for compensating a threshold voltage of a driving switch DT in the pixels 100.
Specifically, the pixel 100 includes a first Scan line Scan1, a second Scan line Scan2, a third Scan line Scan3, a first Data line Data, a sensing line Sen, a light emitting unit OLED, a first switch T1, a second switch T2, a driving switch DT, and a repair switch T3. The first Scan line Scan1, the second Scan line Scan2 and the third Scan line Scan3 are arranged in parallel, and the first Data line Data and the sensing line Sen are arranged in parallel; the input end of the first switch T1 is connected with the first Data line Data, the control end of the first switch T1 is connected with the first Scan line Scan1, the output end of the first switch T1 is connected with the control end of the driving switch DT, and a first node N1 is provided between the output end of the first switch T1 and the control end of the driving switch DT.
The input end of the driving switch DT is connected with a power line, the power line inputs VDD voltage for the driving switch DT, the output end of the driving switch DT is connected with one end of the light emitting unit OLED for providing working voltage (VDD voltage) for the light emitting unit, and the other end of the light emitting unit OLED is connected with a low voltage end VSS. Also, there is a second node N2 between the output terminal of the driving switch DT and the light emitting unit OLED.
The input end of the second switch T2 is connected with the second node N2, the control end of the second switch T2 is connected with the second trace Scan2, and the output end of the second switch T2 is connected with the sensing line Sen. The pixel 100 further includes a storage capacitor Cst, one end of which is connected to the first node N1, and the other end of which is connected to the second node N2.
The repair switch T3 is a four-terminal device, a source electrode of the repair switch T3 is connected with a low-voltage source with constant low voltage, a drain electrode of the repair switch T3 is connected with the first node N1, a top grid electrode of the repair switch T3 is connected with the third scanning line Scan3, and a bottom grid electrode of the repair switch T3 is connected with the sensing line Sen.
It should be noted that, the pixel 100 driving circuit in the embodiment of the present application is based on the improvement of the 2T1C structure, and when the pixel 100 driving circuit adopts the 3T1C structure, the 4T1C structure and other structures, the scheme in the embodiment of the present application is also applicable, and only needs to perform adaptive adjustment, for example, other transistors are added between the driving switch DT and the light emitting unit OLED.
The compensation circuit 200 includes a compensation module 210, a first compensation switch SW1 and a second compensation switch SW2, the sensing line Sen is connected to the reference voltage line Vref through the first compensation switch SW1, one end of the compensation module 210 is connected to the sensing line Sen through the second compensation switch SW2, and the other end of the compensation module 210 is connected to the first Data line Data.
Specifically, the compensation module 210 includes an analog-to-digital converter (analog to digtal converter, ADC), a calculation conversion unit 211, a storage unit 212, a compensation unit 213, and a digital-to-analog converter (digtal to analog converter, DAC), where the sensing line Sen is specifically connected to the analog-to-digital converter ADC through the second compensation switch SW2, and the analog-to-digital converter ADC converts the sensed voltage obtained by the detection into sensed data; the calculation conversion unit 211 is connected with the analog-to-digital converter, and calculates the converted sensing data to obtain a compensation value through a compensation formula or a compensation preset value; the storage unit 212 is connected to the calculation conversion unit 211, and is configured to store the calculated compensation value; the compensation unit 213 is connected to the storage unit 212, and in the process of displaying the pixel 100, the compensation value stored in the storage unit 212 is transmitted to the DAC together with the voltage data output by the data driving chip, and the DAC converts the compensation value and the voltage data into a voltage signal and outputs the voltage signal to the corresponding pixel 100 through the data line.
Fig. 3 is a schematic diagram of transfer characteristics of the repair switch, as shown in fig. 3, the abscissa represents a gate-source Voltage (VGS) of the repair switch T3, and the ordinate represents a source-drain current (IDS) of the repair switch T3, and shows a relationship between the gate-source voltage and the source-drain current of the repair switch T3 when a Bottom Gate (BG) voltage of the repair switch T3 is equal to-2V, 0V, 2V, and 4V.
As can be seen from the figure, when the bottom gate voltage of the repair switch T3 is changed, the relationship curve between the gate-source voltage and the source-drain current of the repair switch T3 is changed, that is, the transfer characteristic of the repair switch T3 is shifted with the voltage of the Bottom Gate (BG), and when the repair switch T3 is an N-type four-terminal thin film transistor, the higher the BG voltage, the more the transfer characteristic is biased negatively.
Therefore, when the gate-source voltage of the repair switch T3 is fixed, the higher the BG voltage, the greater the degree of opening of the repair switch T3. Based on this characteristic of the four-terminal device, the bottom gate is controlled with the voltage on the sensing line Sen, and the voltage on the sensing line Sen is strongly correlated with the threshold voltage shift amount of the driving switch DT, the more positively the threshold voltage of the driving switch DT is, the higher the voltage on the sensing line Sen, and thus the more severely the driving switch DT characteristic shift, the higher the repair switch T3 in the pixel 100 is turned on.
Based on this principle, in the embodiment of the present application, by adding the third Scan line Scan3 and the repair switch T3 in the pixel 100, where the repair switch T3 has four connection ends, the source of the repair switch T3 is connected to the low voltage source, the drain is connected to the output end of the first switch T1, the top gate is connected to the third Scan line Scan3, and the bottom gate is connected to the sensing line Sen; when the third line Scan3 is turned on, the repair switch T3 can input a lower voltage to the gate of the driving switch DT, so that the driving switch DT is in a negative bias state, and the degradation problem of the repair driving switch DT caused by continuous positive bias during long-time use is solved, thereby avoiding the increase of the energy consumption of the driving chip.
In addition, the embodiment of the application not only can compensate the threshold voltage of the driving switch DT in the pixel 100 by the compensation circuit 200, but also can avoid the problem of displaying images caused by drift of the threshold voltage of the driving switch DT due to factors such as manufacturing process or aging.
In this embodiment of the present application, the first Data line Data and the sensing line Sen are disposed in the same layer, the first Scan line Scan1, the second Scan line Scan2 and the third Scan line Scan3 are disposed in the same layer, and the first Scan line Scan1 is located between the second Scan line Scan2 and the third Scan line Scan 3.
Meanwhile, the first switch T1, the second switch T2, and the driving switch DT are located between the first Scan line Scan1 and the second Scan line Scan2, and the repair switch T3 is located between the first Scan line Scan1 and the third Scan line Scan 3. Moreover, the spacing between the first Scan line Scan1 and the third Scan line Scan3 is smaller than the spacing between the second Scan line Scan2 and the third Scan line Scan3 to avoid an excessive increase in the size of the pixel 100.
Further, the sensing line Sen is located between the first Scan line Scan1 and the substrate of the organic light emitting display panel. In the organic light-emitting display panel, a switch functional layer and a light-emitting display layer are arranged between a substrate and a cover plate, a sensing line Sen and a first scanning line Scan1 are both positioned in the switch functional layer, the sensing line Sen is arranged below the scanning line, the bottom grid electrode of a repair switch T3 is more conveniently connected with the sensing line Sen, the top grid electrode of the repair switch T3 is also conveniently connected with a third scanning line Scan3, the circuit design is facilitated, and the winding is reduced.
Correspondingly, as shown in fig. 4, the embodiment of the present application further provides a driving method of the display device, where the driving method includes the steps of:
initial stage a: starting a first scanning line, starting a first switch and a first compensation switch, enabling the first switch to output data voltage, and enabling a sensing line to be connected with reference voltage;
sensing phase B: opening a second line, and opening a second switch to enable the voltage on the sensing line to rise until the voltage on the sensing line is equal to the difference value between the data voltage and the threshold voltage of the driving switch;
compensation stage C: opening a second compensation switch, detecting the voltage on the sensing line to obtain sensing voltage, calculating a compensation value of the driving switch according to the sensing voltage by a compensation module, and compensating the driving switch;
repairing stage D: when the threshold voltage of the driving switch is larger than a preset value, a third line is started, and a repairing switch is opened, so that the gate source voltage of the driving switch is smaller than zero.
As shown in fig. 1 and 5, in the initial stage a, the first Scan line Scan1 is turned on and controls the first switch T1 to be turned on, the voltage Vdata is written into the N1 node, and the first compensation switch SW1 is turned on to write the voltage on the sensing line Sen as the reference voltage Vref.
In the sensing stage B, the first switch T1 is continuously turned on, the second trace Scan2 turns on the second switch T2, the drain electrode of the driving switch DT is connected to the VDD voltage, the gate electrode (N1 node) of the driving switch DT is connected to the data driving voltage (Vdata), the voltage of the source electrode (N2 node) of the driving switch DT starts to rise (flowing), and the voltage on the N2 node and the sensing line Sen starts to rise from the reference voltage until the sensing voltage (Vsen) =the data driving voltage (Vdata) on the sensing line sen—the threshold voltage (Vth) of the driving switch DT, and the gate-source voltage difference of the driving switch DT is automatically turned off when the voltage is equal to the threshold voltage.
In the compensation phase C, when the above condition is reached, the first switch T1 and the second switch T2 are continuously turned on, and the second compensation switch SW2 is turned on, so that the sensing voltage Vsen on the sensing line Sen is sensed and recorded, and the corresponding threshold voltage compensation value can be converted by the calculation and conversion unit 211 and stored in the storage unit 212.
In the repair phase D, the first switch T1 is turned off, then the third trace Scan3 is turned on, and then the second switch T2 is turned off. For the pixel 100 where the driving switch DT is degraded beyond the preset condition, that is, when the threshold voltage of the driving switch DT is greater than the preset value, the repair switch T3 in the pixel 100 is turned on, the low voltage VGL provided by the low voltage source is written into the N1 node, and N2 is the voltage on the sensing line Sen; at this time, the gate-source voltage of the driving switch DT is smaller than zero, the driving switch DT is in a negative bias state, and the characteristics of the driving switch DT are repaired. When the degradation does not exceed the preset condition, the pixel 100 is provided with the driving switch DT, and the voltage on the sensing line Sen is low, the voltage applied to the bottom gate of the repairing switch T3 in the pixel 100 is low, and the high voltage of the third trace Scan3 is insufficient to turn on the repairing switch T3, so that the repairing switch T3 is not repaired.
Specifically, the preset value is 2V, that is, when the threshold voltage of the driving switch DT is detected to be greater than 2V, the third trace Scan3 is turned on, and the repair switch T3 is turned on to repair the driving switch DT. Of course, the preset value may be specifically selected according to the actual situation.
In this embodiment, when the threshold voltage of the driving switch DT in one pixel 100 is greater than a preset value, the third Scan line Scan3 in all pixels 100 is turned on at the same time, and the repair switch T3 in all pixels 100 is turned on, so that the gate-source voltage of the driving switch DT in all pixels 100 is less than zero. At this time, the whole pixel 100 can be simultaneously turned on for repair, so as to improve repair efficiency; moreover, the third Scan lines Scan3 in all the pixels 100 can be driven at the same time, and the design of the circuit is simplified. Of course, in other embodiments, the driving switches DT in different pixels 100 may be repaired separately, and the repairing of the driving switches DT of a specific number of pixels 100 or pixels 100 in one area may be performed, so that the repairing is more targeted.
The third Scan lines Scan3 in all the pixels 100 can be connected to the same control line, and the control line is connected to the gate driving circuit, so as to turn on the third Scan lines Scan3 in all the pixels 100 at the same time, and avoid the problem of excessive wiring of the frame of the organic light emitting display panel.
As shown in fig. 5, in the repair phase D, the on time of the second trace Scan2 is shorter than the on time of the third trace Scan3, the second trace Scan2 is turned off after the repair phase is turned on for a certain time, and the third trace Scan3 is continuously turned on. When the second trace Scan2 and the third trace Scan3 are turned on simultaneously, the second switch T2 and the repair switch T3 are turned on, the low voltage VGL accessed by the source of the repair switch T3 is written into the node N1 of the first node, and the second node N2 is a sensing voltage at this time, so that the driving switch DT is in a negative bias state; when the second trace Scan2 is turned off, the second switch T2 is turned off, and the driving switch DT is in a repaired state, so as to avoid excessive repair of the threshold voltage of the driving switch DT and influence on the characteristics of the driving switch DT.
It should be noted that, the display period of the organic light emitting display panel includes a display period and a non-display period, one display period is a process of waking up and closing a screen of the organic light emitting display panel once, the display period is a process of displaying a picture, the non-display period is two parts before and after the display period, specifically includes a startup non-display period a and a shutdown non-display period b, the organic light emitting display panel is started when receiving a driving enabling signal, and enters the startup non-display period a; and powering off when receiving the drive disable signal, and entering a powering off non-display stage b.
Since accurate sensing of the threshold voltage of the driving switch DT requires the driving switch DT to turn off itself, the closer to the off voltage, the smaller the current of the driving switch DT, so the sensing takes longer. The sensing process requires data voltage coordination and therefore cannot be completed within a normal display frame; the vertical blanking period c between adjacent display frames is not long enough to complete the sensing of one row of pixels 100, so the embodiments of the present application place the sensing operation of the threshold voltage in the non-display period (i.e. the on-non-display period and the off-non-display period) after the power-on and before the power-off.
As one implementation manner, as shown in fig. 6, the embodiment of the present application makes an initial stage, a sensing stage, a compensation stage and a repair stage in one display period, where the initial stage, the sensing stage and the compensation stage are located in the power-on non-display stage a, and the repair stage is located in the power-off non-display stage b.
In other embodiments, the initial phase, the sensing phase, the compensation phase, and the repair phase may be located in different display periods. Alternatively, one or more of the initial stage, the sensing stage, and the compensation stage are located in the shutdown non-display stage b. Or, the repair phase is located in the power-on non-display phase a.
Of course, the initial stage, the sensing stage, the compensation stage and the repair stage may be started as required, for example, only when the threshold voltage of the driving switch DT is detected to reach the level of compensation or repair, and the corresponding steps are performed respectively, which is not limited herein. Fig. 7 is a schematic diagram of a degradation and repair process of a driving switch DT according to an embodiment of the present application, as shown in fig. 7, Δv1 represents a degradation degree of the driving switch DT, Δv2 represents a repair degree of the driving switch DT, so that it can be seen that characteristics of the driving switch DT under normal operation may drift positively, and after the technical scheme in the embodiment of the present application is adopted, the characteristics of the driving switch DT with a negative bias may drift negatively after repairing for a period of time, so as to achieve the purpose of repairing a threshold voltage of the driving switch DT in a pixel 100.
It should be noted that, the limitation of each step in the present solution is not to be considered as limiting the sequence of steps on the premise of not affecting the implementation of the specific solution, and the steps written in the previous step may be executed before, or may be executed after, or may even be executed simultaneously, and the solutions of different embodiments may be combined and applied under the condition of not conflicting, so long as the present solution can be implemented, all should be considered as falling within the protection scope of the present application.
The foregoing is a further detailed description of the present application in connection with specific alternative embodiments, and it is not intended that the practice of the present application be limited to such descriptions. It should be understood that those skilled in the art to which the present application pertains may make several simple deductions or substitutions without departing from the spirit of the present application, and all such deductions or substitutions should be considered to be within the scope of the present application.

Claims (10)

1. A display device comprising an organic light emitting display panel having a plurality of pixels and a compensation circuit connected to the organic light emitting display panel for compensating a threshold voltage of a driving switch in the pixels, characterized in that,
the pixel comprises a first scanning line, a second scanning line, a third scanning line, a first data line, a sensing line, a light emitting unit, a first switch, a second switch, a driving switch and a repairing switch, wherein the input end of the first switch is connected with the first data line, and the control end of the first switch is connected with the first scanning line; the input end of the driving switch is connected with a power line, the control end of the driving switch is connected with the output end of the first switch, and the output end of the driving switch is used for providing working voltage for the light-emitting unit; the input end of the second switch is connected with the output end of the driving switch, the control end of the second switch is connected with the second scanning line, and the output end of the second switch is connected with the sensing line; the source electrode of the repair switch is connected with a low-voltage source, the drain electrode of the repair switch is connected with the output end of the first switch, the top grid electrode of the repair switch is connected with the third scanning line, and the bottom grid electrode of the repair switch is connected with the sensing line;
the compensation circuit comprises a compensation module, a first compensation switch and a second compensation switch, wherein the sensing line is connected with the reference voltage line through the first compensation switch, one end of the compensation module is connected with the sensing line through the second compensation switch, and the other end of the compensation module is connected with the first data line.
2. The display device of claim 1, wherein the first data line and the sensing line are disposed in a same layer, the first scan line, the second scan line, and the third scan line are disposed in a same layer, and the sensing line is located between the third scan line and a substrate of the organic light emitting display panel.
3. The display device of claim 1, wherein the repair switch comprises an N-type four-terminal thin film transistor.
4. The display device of claim 1, wherein the compensation module comprises:
the calculation conversion unit is connected with the sensing line through the second compensation switch and calculates the compensation value of the driving switch according to the sensing voltage on the sensing line;
the storage unit is connected with the calculation conversion unit and used for storing the compensation value; and
and the compensation unit is connected with the storage unit, receives voltage data and outputs the voltage data and the compensation value to the first data line.
5. A driving method of a display device for driving the display device according to any one of claims 1 to 4, comprising the steps of:
the initial stage: starting a first scanning line, starting a first switch and a first compensation switch, enabling the first switch to output data voltage, and enabling a sensing line to be connected with reference voltage;
sensing phase: opening a second scanning line, and opening a second switch to enable the voltage on the sensing line to rise until the voltage on the sensing line is equal to the difference value between the data voltage and the threshold voltage of the driving switch;
and (3) compensation: opening a second compensation switch, detecting the voltage on the sensing line to obtain sensing voltage, calculating a compensation value of the driving switch according to the sensing voltage by a compensation module, and compensating the driving switch;
and (3) a repairing stage: when the threshold voltage of the driving switch is larger than a preset value, a third scanning line is started, and a repairing switch is opened, so that the gate source voltage of the driving switch is smaller than zero.
6. The driving method of a display device according to claim 5, wherein the preset value is 2V.
7. The driving method of a display device according to claim 5, wherein a display period of the organic light emitting display panel includes a display stage and a non-display stage, the non-display stage includes a power-on non-display stage and a power-off non-display stage, the initial stage, the sensing stage and the compensation stage are located in the power-on non-display stage, and the repair stage is located in the power-off non-display stage.
8. The driving method of a display device according to claim 5, wherein in the repair phase, when a threshold voltage of the driving switch in one pixel is greater than a preset value, a third scan line in all pixels is turned on at the same time, and repair switches in all pixels are turned on so that a gate-source voltage of the driving switch in all pixels is less than zero.
9. The driving method of a display device according to claim 8, wherein the third scan line among all pixels is connected to the same control line.
10. The driving method of a display device according to claim 5, wherein an on time of the second scan line is shorter than an on time of the third scan line in the repair stage.
CN202311836910.9A 2023-12-28 Display device and driving method thereof Active CN117594004B (en)

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KR20190038141A (en) * 2017-09-29 2019-04-08 엘지디스플레이 주식회사 Electroluminescence display and driving method thereof
CN113112961A (en) * 2021-04-12 2021-07-13 深圳市华星光电半导体显示技术有限公司 Display drive circuit and drive method of display drive circuit

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Publication number Priority date Publication date Assignee Title
KR20150073420A (en) * 2013-12-23 2015-07-01 엘지디스플레이 주식회사 Organic light emitting display device
KR20150077706A (en) * 2013-12-30 2015-07-08 엘지디스플레이 주식회사 Organic light emitting display device
CN106941135A (en) * 2017-04-11 2017-07-11 武汉华星光电技术有限公司 The method for repairing and mending and organic electroluminescence display panel of a kind of organic electroluminescence display panel
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