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WO2019184449A1 - 液晶显示面板的控制电路、测试设备和测试方法 - Google Patents

液晶显示面板的控制电路、测试设备和测试方法 Download PDF

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Publication number
WO2019184449A1
WO2019184449A1 PCT/CN2018/120507 CN2018120507W WO2019184449A1 WO 2019184449 A1 WO2019184449 A1 WO 2019184449A1 CN 2018120507 W CN2018120507 W CN 2018120507W WO 2019184449 A1 WO2019184449 A1 WO 2019184449A1
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WIPO (PCT)
Prior art keywords
pulse signal
liquid crystal
display panel
crystal display
signal
Prior art date
Application number
PCT/CN2018/120507
Other languages
English (en)
French (fr)
Inventor
王伟伟
郑友
付文华
娄衍礼
汪清
王晓芬
邵鑫
任干
张建
Original Assignee
京东方科技集团股份有限公司
合肥鑫晟光电科技有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 京东方科技集团股份有限公司, 合肥鑫晟光电科技有限公司 filed Critical 京东方科技集团股份有限公司
Priority to US16/482,028 priority Critical patent/US10991323B2/en
Priority to EP18901813.8A priority patent/EP3772057A4/en
Publication of WO2019184449A1 publication Critical patent/WO2019184449A1/zh

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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
    • G09G3/006—Electronic inspection or testing of displays and display drivers, e.g. of LED or LCD displays
    • 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
    • G09G3/34—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 by control of light from an independent source
    • G09G3/36—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 by control of light from an independent source using liquid crystals
    • 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
    • G09G3/34—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 by control of light from an independent source
    • G09G3/36—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 by control of light from an independent source using liquid crystals
    • G09G3/3611—Control of matrices with row and column drivers
    • G09G3/3648—Control of matrices with row and column drivers 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
    • G09G2310/00—Command of the display device
    • G09G2310/02—Addressing, scanning or driving the display screen or processing steps related thereto
    • G09G2310/0243—Details of the generation of driving signals
    • G09G2310/0251—Precharge or discharge of pixel before applying new pixel voltage
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2310/00—Command of the display device
    • G09G2310/06—Details of flat display driving waveforms
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/02—Improving the quality of display appearance
    • G09G2320/0242—Compensation of deficiencies in the appearance of colours
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/02—Improving the quality of display appearance
    • G09G2320/0247—Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
    • 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
    • G09G2330/12—Test circuits or failure detection circuits included in a display system, as permanent part thereof
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2370/00—Aspects of data communication
    • G09G2370/18—Use of optical transmission of display information

Definitions

  • the present disclosure relates to the field of display technology, and in particular, to a control circuit for a liquid crystal display panel, a test device, and a test method of the liquid crystal display panel.
  • the display panel Before the display panel is manufactured, it is generally necessary to go through the testing process. For example, perform a lighting test on the display panel to eliminate bad products. However, in actual production, for those display panels that have been tested and considered to be qualified products, the display quality may still be poor. For example, flicker, black and white spots (mura) occur on the screen when an image is displayed.
  • a control circuit for a liquid crystal display panel includes: a current sensor for detecting a change in an input current of the liquid crystal display panel to generate an indication signal indicating an image displayed by the liquid crystal display panel a switching of a frame; a discharge signal generating circuit configured to receive the indication signal from the current sensor, and the discharge signal generating circuit generates a discharge signal in response to receiving the indication signal such that a common electrode is in the liquid crystal display panel
  • the liquid crystal capacitor composed of the pixel electrode is discharged.
  • the liquid crystal capacitor referred to herein refers to an equivalent capacitor formed by a pixel electrode and a common electrode in a liquid crystal display panel.
  • the indication signal is a first pulse signal having a first duration
  • the discharge signal being a second pulse signal having a second duration equal to the first duration
  • the second pulse signal The liquid crystal capacitor discharges during the second duration.
  • control circuit further includes a discharge control circuit that causes the liquid crystal capacitor to discharge in response to receiving the second pulse signal.
  • the discharge control circuit includes a processor and a level selection circuit, the level selection circuit including a first transistor and a second transistor, the first end of the first transistor and the second end of the second transistor being electrically connected, The second end of the second transistor is for receiving a high level signal, the first end of the second transistor is for receiving a low level signal, and the control ends of the first transistor and the second transistor are electrically connected to the output end of the processor
  • the input of the processor is for receiving the second pulse signal.
  • the discharge signal generating circuit includes a second pulse signal generating circuit and a third pulse signal generating circuit
  • the third pulse signal generating circuit is configured to receive the first pulse signal to generate a third pulse signal
  • the second pulse The signal generating circuit is configured to receive the third pulse signal to generate the second pulse signal
  • the third duration of the third pulse signal is equal to the first duration
  • the pulse amplitude of the second pulse signal is greater than the pulse of the third pulse signal Amplitude.
  • the third pulse signal generating circuit includes an optical coupler for receiving the first pulse signal, and a first capacitor electrically coupled to the output of the optical coupler end.
  • the second pulse signal generating circuit includes a relay and a driving circuit thereof, and the driving circuit receives the third pulse signal to drive the relay to output the second pulse signal.
  • the current sensor generates the indication signal in response to the magnitude of the change in the input current exceeding 10%.
  • Another embodiment of the present disclosure provides a test apparatus for a liquid crystal display panel, including the control circuit of any of the foregoing embodiments.
  • the test device includes a voltage input port for receiving an external power supply voltage and a voltage output port for supplying an operating voltage to the liquid crystal display panel to generate the input current, wherein the current is A sensor is electrically coupled between the voltage input port and the voltage output port to detect a change in the input current.
  • the test apparatus includes an image signal output interface for electrically connecting to the liquid crystal display panel to provide an image signal to the liquid crystal display panel.
  • Yet another embodiment of the present disclosure provides a testing method for a liquid crystal display panel, the liquid crystal display panel including a common electrode and a pixel electrode, wherein the method includes: providing an image signal to the liquid crystal display panel for image display;
  • a change in the input current of the liquid crystal display panel is detected to determine whether image frame switching has occurred; and in response to detecting that image frame switching has occurred, the liquid crystal capacitor composed of the common electrode and the pixel electrode in the liquid crystal display panel is discharged.
  • the testing method includes detecting a change in the input current using a current sensor and generating a first pulse signal having a first duration, the first pulse signal indicating occurrence of an image frame switch; in response to generating the first The pulse signal generates a second pulse signal having a second duration equal to the first duration, the second pulse signal causing the liquid crystal capacitor to discharge during the second duration.
  • the liquid crystal display panel includes a discharge switch and a discharge control circuit in series with the liquid crystal capacitor, the test method including: providing the second pulse signal to the discharge control circuit, and the discharge control circuit is responsive to The discharge switch is turned on by receiving the second pulse signal.
  • the testing method further includes: generating a third pulse signal based on the first pulse signal before generating the second pulse signal, the third duration of the third pulse signal being equal to the first duration Generating the second pulse signal based on the third pulse signal, the pulse amplitude of the second pulse signal being greater than the pulse amplitude of the third pulse signal.
  • FIG. 1 schematically shows a structural block diagram of a control circuit and a display panel according to an embodiment of the present disclosure
  • FIG. 3 schematically shows a structural block diagram of a control circuit and a display panel according to another embodiment of the present disclosure
  • FIG. 4 schematically illustrates a discharge control circuit and a discharge circuit of a liquid crystal capacitor in accordance with an embodiment of the present disclosure
  • FIG. 5 schematically illustrates a third pulse signal generation circuit in a control circuit in accordance with an embodiment of the present disclosure
  • FIG. 6 schematically illustrates a second pulse signal generation circuit in a control circuit in accordance with an embodiment of the present disclosure
  • FIG. 7 schematically illustrates a block diagram of a test apparatus for a liquid crystal display panel in accordance with one embodiment of the present disclosure.
  • FIG. 1 schematically shows a block diagram of a control circuit 10 and a liquid crystal display panel 20 for a liquid crystal display panel according to an embodiment of the present disclosure.
  • the control circuit 10 includes a current sensor 101 and a discharge signal generating circuit 102 for detecting a change in the input current of the liquid crystal display panel 20 to generate an indication signal indicating switching of an image frame displayed by the liquid crystal display panel.
  • the discharge signal generating circuit 102 is for receiving an indication signal from the current sensor 101, and the discharge signal generating circuit 102 generates a discharge signal in response to receiving the indication signal, so that the liquid crystal capacitor composed of the common electrode and the pixel electrode in the liquid crystal display panel 20 Discharge.
  • the display panel 20 includes a discharge control circuit 201 for controlling discharge of a liquid crystal capacitor in the display panel.
  • the control circuit proposed in the embodiment of the present disclosure can be applied to a test process of a liquid crystal display panel, such as a lighting detection process before leaving the factory, thereby improving the quality of the display screen of the liquid crystal display panel and further improving the product yield.
  • a test process of a liquid crystal display panel such as a lighting detection process before leaving the factory
  • the principle that the control circuit proposed by the embodiment of the present disclosure can improve the image display quality of the liquid crystal display panel is specifically described.
  • the potential of the common electrode in the liquid crystal display panel is generally used as a reference potential, and the potential of the pixel electrode is dependent on the image data signal.
  • the image data signal is typically a varying signal, which may be higher than the reference potential of the common electrode or lower than the reference potential of the common electrode. That is to say, if the reference potential of the common electrode is used as a reference, the image data signal includes a data signal having a positive value and an image signal having a negative value, and the data signals of images of different frames may also be different, such as Figure 2 shows.
  • V-com ideal electrode potential
  • the actual common electrode potential may be lower than the ideal common electrode potential (eg, the difference is n), resulting in a positive data signal D+ relative to the reference potential (N+n)V, negative
  • the potential of the data signal D- with respect to the reference potential is (Nn)V. Therefore, when the common electrode potential deviates from the above ideal value, the positive data signal and the negative data signal will have different absolute values, which may cause voltage imbalance in controlling the deflection of the liquid crystal molecules during the lighting test, thereby causing the liquid crystal capacitor to be Charge transfer occurs between them, and charges are stored on the common electrode. This charge transfer may continue to occur as images of different frames are displayed during the test.
  • the inventors of the present applicant have recognized that during the testing of an existing liquid crystal display panel, a large amount of electric charge may be stored on the common electrode, which is disadvantageous for displaying an image on the liquid crystal display panel, which may cause flickering, black and white spots, etc. unpleasant sight.
  • the current touch sensor in the control circuit can generate an indication signal indicating that the image frame displayed by the liquid crystal display panel is switched by detecting a change in the input current of the liquid crystal display panel.
  • the discharge signal generating circuit After receiving the indication signal, the discharge signal generating circuit generates a discharge signal that is supplied to the display panel.
  • the discharge signal can be received, for example, by a discharge control circuit disposed on the display panel to discharge the liquid crystal capacitor of the liquid crystal display panel.
  • applying the control circuit provided by the embodiment of the present disclosure to the test process of the liquid crystal display panel can implement a discharge process on the liquid crystal capacitor between time periods in which images of different frames are displayed. Thereby, it is possible to avoid a large amount of charges accumulated on the common electrode and improve the quality of the image displayed on the liquid crystal display panel.
  • the current required for the liquid crystal display panel to display images of different frames is different. Therefore, it can be determined whether the displayed image frame is switched by detecting the change of the input current of the liquid crystal display panel.
  • the current sensor is configured to detect that the magnitude of the change in the input current exceeds a threshold (eg, 10%) to generate an indication signal, ie, detecting that the magnitude of the change in the input current exceeds the threshold is considered an image frame occurrence Switched to display the image of the next frame.
  • a threshold eg, 10%
  • the current sensor can be placed in the power circuit of the liquid crystal display panel.
  • the current sensor can be connected in series in a power supply line that supplies an operating voltage to the liquid crystal display panel.
  • the indication signal output by the current sensor is a first pulse signal P1 having a first duration
  • the discharge signal being a second pulse signal P2 having a second duration equal to the first duration
  • second The pulse signal causes the liquid crystal capacitor to discharge during the second duration. That is to say, the discharge signal is generated in response to the indication signal, and also ends with the end of the indication signal, such that the liquid crystal capacitor is discharged only in a short time during which image frame switching occurs, so that the liquid crystal display can be avoided or reduced.
  • the panel normally shows the effect of the image.
  • the discharge control circuit for controlling the discharge of the liquid crystal capacitor in the display panel may be disposed in the liquid crystal display panel, but alternatively, the discharge control circuit may be disposed in the control circuit.
  • the control circuit 10 further includes a discharge control circuit 103 that discharges the liquid crystal capacitor in response to receiving a discharge signal (i.e., the second pulse signal P2) from the discharge signal generating circuit 102.
  • FIG. 4 shows an example of a discharge control circuit, and in order to more clearly understand the discharge process of the liquid crystal capacitor, FIG. 4 also schematically shows the liquid crystal capacitor C and the discharge circuit.
  • the discharge circuit of the liquid crystal capacitor includes a discharge switch (for example, a TFT) connected in series thereto, and one end of the liquid crystal capacitor C is electrically connected to a pixel switch (for example, a TFT) to receive a data signal data.
  • Examples of the discharge control circuit 103 include a processor MCU and a processor-controlled level selection circuit 103a.
  • the processor MCU can be electrically coupled to the discharge signal generating circuit 102 to receive a discharge signal from the discharge signal generating circuit.
  • FIG. 4 shows an example of a discharge control circuit, and in order to more clearly understand the discharge process of the liquid crystal capacitor, FIG. 4 also schematically shows the liquid crystal capacitor C and the discharge circuit.
  • the discharge circuit of the liquid crystal capacitor includes a discharge switch (for example, a TFT) connected in series thereto, and
  • the level selection circuit 103a includes a first transistor T1 and a second transistor T2 electrically connected in series, the first transistor for receiving a high level signal VH and the second transistor for receiving a low level signal VL .
  • the high level signal VH is, for example, a positive potential signal having a constant amplitude, for example, 1.8V, 3.3V, etc.
  • the low level signal VL is, for example, a zero potential signal or has a constant amplitude.
  • the negative potential signal of the value for example -1.8V, -3.3V, etc.
  • the processor When the processor does not receive the discharge signal from the discharge signal generating circuit, it can control the first transistor T1 to be turned off, and turn on the second transistor T2, thereby outputting a low level signal to the control terminal of the discharge TFT, the discharge TFT The off state is maintained (in this example, the discharge TFT is an N-type TFT).
  • the processor receives the discharge signal from the discharge signal generating circuit, it can control the first transistor T1 to be turned on, and the second transistor T2 is turned off. At this time, the control terminal of the discharge TFT receives the high level VH, and the discharge TFT Turn on to achieve discharge of the liquid crystal capacitor.
  • FIG. 4 only shows an example of a discharge control circuit, and those skilled in the art can design an alternative of many discharge control circuits based on the principles disclosed herein, and all of the alternatives are included in the spirit of the present disclosure. The scope of protection of this application.
  • the discharge signal generating circuit includes a second pulse signal generating circuit 102b and a third pulse signal generating circuit 102a.
  • the third pulse signal generating circuit 102a is configured to receive the first pulse signal P1 to generate a third pulse signal P3
  • the second pulse signal generating circuit is configured to receive the third pulse signal p3 to generate the second pulse signal P2, the third duration of the third pulse signal being equal to the first duration, the second pulse signal
  • the amplitude of the pulse is greater than the amplitude of the pulse of the third pulse signal.
  • the third pulse signal generating circuit includes an optical coupler OP and a first capacitor C1.
  • the input end of the optical coupler OP is for receiving the first pulse signal P1, and the first capacitor C1 is electrically Connected to the output of the optocoupler, a second pulse signal P2 is generated at the output of the optocoupler.
  • a first fixed level for example , 1.8V
  • the output of the optocoupler communicates with the first fixed level signal receiving end to generate a voltage signal.
  • the capacitor C1 can be discharged with the end of the first pulse signal P1, thereby generating a third pulse signal. It can be understood that the resistance of the discharge circuit in which the capacitor C1 is located can be designed to control the discharge time of the capacitor C1 such that the third duration of the third pulse signal is equal to the first duration. Therefore, in this example, the amplitude of the third pulse signal is approximately 1.8V.
  • the second pulse signal generating circuit 102b includes a relay and its driving circuit.
  • the driving circuit DR receives the third pulse signal P3 and drives the relay RL to output the second pulse signal P2.
  • the output of the relay is not turned on with the second fixed level (eg, 3.3V) signal receiving end
  • the drive circuit DR receives
  • the third pulse signal P3 is connected, the output terminal of the control relay is in communication with the second fixed level signal receiving end, so that the second fixed level signal is output from the output end of the relay.
  • the drive circuit DR may include a switch controlled by the third pulse signal P3, and when the third pulse signal P3 ends, the output of the relay is also disconnected from the second fixed level signal receiving end.
  • the amplitude of the third pulse signal is 3.3V.
  • the indication signal from the current sensor is actually converted into the second pulse signal having a larger amplitude, and the amplitude is higher.
  • the large second pulse signal is not directly obtained by amplifying the indication signal output by the current sensor, and the second pulse signal is generated in response to the indication signal, but is independent of the indication signal of the current sensor, which is to improve the discharge control circuit. It is advantageous to control the accuracy of the discharge of the liquid crystal capacitor in response to an indication signal from the current sensor.
  • the control circuit can include a power conversion circuit capable of receiving an external supply voltage to generate various magnitudes of DC voltage, for example, 1.8V, 3.3V, which can also be generated for various circuit units within the control circuit.
  • the operating voltage is not detailed here.
  • the control circuit provided by the embodiment of the present disclosure can be applied to a test process of a liquid crystal display panel, and in particular, the control circuit can control the liquid crystal capacitor in the liquid crystal display panel to discharge during the test.
  • another embodiment of the present disclosure provides a test apparatus for a liquid crystal display panel including the control circuit of any of the foregoing embodiments.
  • the test apparatus of the liquid crystal display panel includes the control circuit 10 described in the foregoing embodiment, and the test apparatus can test the completed liquid crystal display panel to provide a yield of the product.
  • the test equipment can be in various forms, for example the test equipment can be in the form of a test board.
  • the test device includes a voltage input port Vin for receiving an external voltage and a voltage output port for supplying an operating voltage to the liquid crystal display panel to generate a current.
  • the input current detected by the sensor, the current sensor can be electrically connected between the voltage input port and the voltage output port to detect a change in the input current.
  • the test apparatus includes an image signal output interface Dout for electrically connecting with the liquid crystal display panel to supply an image signal to the liquid crystal display panel.
  • the liquid crystal display panel is tested by using the test device provided by the embodiment of the present disclosure, and the liquid crystal capacitor in the liquid crystal display panel can be discharged for a short time during the test, and at least the electric charge accumulated on the common electrode can be reduced. It is beneficial to improve the quality of the displayed image of the liquid crystal display panel after leaving the factory, and further improve the yield of the product.
  • a further embodiment of the present disclosure provides a testing method for a liquid crystal display panel, the method comprising: providing an image signal to a liquid crystal display panel for image display; detecting an input of the liquid crystal display panel The change in current is to determine whether image frame switching has occurred, and in response to detecting that image frame switching has occurred, the liquid crystal capacitor composed of the common electrode and the pixel electrode in the liquid crystal display panel is discharged.
  • a current sensor may be used to detect the change of the input current and generate a first pulse signal having a first duration, the first pulse signal indicating that the liquid crystal display panel displays Switching of image frames.
  • the testing method can include generating, in response to generating the first pulse signal, a second pulse signal having a second duration equal to the first duration, the second pulse signal causing the liquid crystal capacitor to discharge during the second duration .
  • the liquid crystal display panel includes a discharge switch and a discharge control circuit in series with the liquid crystal capacitor, the test method comprising: providing the second pulse signal to the discharge control circuit, and the discharge control circuit is responsive to receiving the second The discharge switch is turned on by a pulse signal. At this time, the liquid crystal capacitor can be discharged through the discharge loop in which the discharge switch is located for the duration of the second pulse signal, thereby reducing or removing the electric charge accumulated on the common electrode.
  • the testing method may further include: generating a third pulse signal based on the first pulse signal, the third duration of the third pulse signal and the first duration before generating the second pulse signal The time is equal; generating the second pulse signal based on the third pulse signal, the pulse amplitude of the second pulse signal being greater than the pulse amplitude of the third pulse signal.
  • first duration of the first pulse signal, the second duration of the second pulse signal, and the third duration of the third pulse signal may not be absolutely equal, for example, In some embodiments, they may have a difference of milliseconds between each other.
  • the embodiment of the testing method for the liquid crystal display panel proposed by the embodiment of the present disclosure has similar technical effects as the foregoing embodiment of the control circuit and the testing device, and details are not described herein again.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)
  • Liquid Crystal Display Device Control (AREA)

Abstract

一种用于液晶显示面板（20）的控制电路（10）、测试设备和测试方法；控制电路（10）包括电流传感器（101）和放电信号生成电路（102）；电流传感器（101）用于检测液晶显示面板（20）的输入电流的变化而产生指示信号，指示信号表明液晶显示面板（20）所显示的图像帧的切换；放电信号生成电路（102），用于从电流传感器（101）接收指示信号，并且放电信号生成电路（102）响应于接收到指示信号而生成放电信号，使得液晶显示面板（20）中由公共电极和像素电极构成的液晶电容器（C）放电；由此可改进液晶显示面板（20）显示图像的质量，提升产品良率。

Description

液晶显示面板的控制电路、测试设备和测试方法
相关申请的交叉引用
本申请要求于2018年3月27日向中国专利局提交的专利申请201810259258.1的优先权利益，并且在此通过引用的方式将该在先申请的内容并入本文。
技术领域
本公开涉及显示技术领域，特别地，涉及用于液晶显示面板的控制电路、测试设备和液晶显示面板的测试方法。
背景技术
随着技术的进步和人们生活水平的提升，人们对电子显示设备的图像显示质量也存在越来越高的要求，例如，更高的分辨率或刷新率总是被期望的。由于氧化物的电子迁移速率远高于非晶硅的电子迁移率，所以，在当前的显示设备中，氧化物半导体晶体管被广泛应用。
在显示面板制作完成出厂之前，一般需要经历测试过程。例如，对显示面板进行点灯测试，以排除不良产品。然而，在实际生产中，对于那些经过测试并被视为合格产品的显示面板，仍会发生显示质量不佳的情形。例如，在显示图像时屏幕发生闪烁(flicker)、黑白斑点(mura)等现象。
发明内容
根据本公开实施例提供的用于液晶显示面板的控制电路包括：电流传感器，用于检测所述液晶显示面板的输入电流的变化而产生指示信号，所述指示信号表明液晶显示面板所显示的图像帧的切换；放电信号生成电路，用于从所述电流传感器接收所述指示信号，并且所述放电信号生成电路响应于接收到所述指示信号而生成放电信号，使得液晶显示面板中由公共电极和像素电极构成的液晶电容器放电。本文提到的液晶电容器指的是液晶显示面板中的像素电极和公共电极形成的等效电容器。
在一些实施例中，指示信号是具有第一持续时间的第一脉冲信号， 所述放电信号是具有与第一持续时间相等的第二持续时间的第二脉冲信号，所述第二脉冲信号使得所述液晶电容器在所述第二持续时间内放电。
在一些实施例中，控制电路还包括放电控制电路，放电控制电路响应于接收到所述第二脉冲信号而使得所述液晶电容器放电。
在一些实施例中，放电控制电路包括处理器和电平选择电路，电平选择电路包括第一晶体管和第二晶体管，第一晶体管的第一端和第二晶体管的第二端电连接，第二晶体管的第二端用于接收高电平信号，第二晶体管的第一端用于接收低电平信号，第一晶体管和第二晶体管的控制端电电连接至所述处理器的输出端，处理器的输入端用于接收第二脉冲信号。
在一些实施例中，放电信号生成电路包括第二脉冲信号生成电路和第三脉冲信号生成电路，第三脉冲信号生成电路用于接收所述第一脉冲信号而生成第三脉冲信号，第二脉冲信号生成电路用于接收第三脉冲信号而生成所述第二脉冲信号，第三脉冲信号的第三持续时间与第一持续时间相等，第二脉冲信号的脉冲幅值大于第三脉冲信号的脉冲幅值。
在一些实施例中，第三脉冲信号生成电路包括光耦合器和第一电容器，所述光耦合器的输入端用于接收所述第一脉冲信号，第一电容器电连接至光耦合器的输出端。
在一些实施例中，第二脉冲信号生成电路包括继电器及其驱动电路，驱动电路接收所述第三脉冲信号而驱动所述继电器输出所述第二脉冲信号。
在一些实施例中，电流传感器响应于所述输入电流的变化幅度超过10％，而产生所述指示信号。
本公开的另一实施例提供了一种用于液晶显示面板的测试设备，包括前述实施例中任一实施例所述的控制电路。
在一些实施例中，测试设备包括电压输入端口和电压输出端口，电压输入端口用于接收外部电源电压，电压输出端口用于向液晶显示面板提供工作电压以产生所述输入电流，其中所述电流传感器电连接在电压输入端口和电压输出端口之间以检测所述输入电流的变化。
在一些实施例中，测试设备包括图像信号输出接口，其用于与液 晶显示面板电连接以向液晶显示面板提供图像信号。
本公开的又一实施例提供了一种用于液晶显示面板的测试方法，液晶显示面板包括公共电极和像素电极，其中所述方法包括：向液晶显示面板提供图像信号以进行图像显示；
检测液晶显示面板的输入电流的变化以判断是否发生图像帧切换；响应于检测到发生图像帧切换，对液晶显示面板中由公共电极和像素电极构成的液晶电容器进行放电。
在一些实施例中，测试方法包括：使用电流传感器检测所述输入电流的变化并生成具有第一持续时间的第一脉冲信号，所述第一脉冲信号表明发生图像帧切换；响应于生成第一脉冲信号，生成具有与第一持续时间相等的第二持续时间的第二脉冲信号，所述第二脉冲信号使得所述液晶电容器在所述第二持续时间内放电。
在一些实施例中，液晶显示面板包括与所述液晶电容器串联的放电开关及放电控制电路，所述测试方法包括：将所述第二脉冲信号提供给所述放电控制电路，放电控制电路响应于接收到第二脉冲信号而接通所述放电开关。
在一些实施例中，测试方法还包括：在生成所述第二脉冲信号之前，基于所述第一脉冲信号而生成第三脉冲信号，第三脉冲信号的第三持续时间与第一持续时间相等；基于所述第三脉冲信号生成所述第二脉冲信号，第二脉冲信号的脉冲幅值大于第三脉冲信号的脉冲幅值。
附图说明
图1示意性地示出了根据本公开的一个实施例的控制电路和显示面板的结构框图；
图2用于图示在液晶显示面板在测试过程中发生的电荷转移现象；
图3示意性地示出了根据本公开的另一实施例的控制电路和显示面板的结构框图；
图4示意性地示出了根据本公开的一个实施例的放电控制电路及液晶电容器的放电回路；
图5示意性地示出了根据本公开的一个实施例的控制电路中的第三脉冲信号生成电路；
图6示意性地示出了根据本公开的一个实施例的控制电路中的第 二脉冲信号生成电路；
图7示意性地示出了根据本公开的一个实施例的用于液晶显示面板的测试设备的框图。
具体实施方式
下面，通过举例的方式来详细说明本公开的具体实施例。应当理解的是，本公开的实施例不局限于以下所列举的示例，本领域技术人员利用本公开的原理或精神可以对所示出的各实施例进行修改和变型，得到形式不同的其它实施例，显然，这些实施例都落入本申请要求保护的范围。
图1示意性地示出了根据本公开实施例提供的用于液晶显示面板的控制电路10和液晶显示面板20的框图。控制电路10包括电流传感器101和放电信号生成电路102，电流传感器101用于检测液晶显示面板20的输入电流的变化而产生指示信号，该指示信号表明液晶显示面板所显示的图像帧的切换。放电信号生成电路102用于从电流传感器101接收指示信号，并且放电信号生成电路102响应于接收到所述指示信号而生成放电信号，使得液晶显示面板20中由公共电极和像素电极构成的液晶电容器放电。在图1中，还示出了显示面板20包括放电控制电路201，其用于控制显示面板中液晶电容器的放电。
本公开实施例提出的控制电路可应用于液晶显示面板的测试过程，例如出厂前的点灯检测过程，从而提升液晶显示面板显示画面的品质，进一步提升产品良率。接下来，具体说明本公开实施例提出的控制电路可提升液晶显示面板的图像显示质量的原理。
液晶显示面板中的公共电极的电位通常作为参考电位，而像素电极的电位则取决于图像数据信号。图像数据信号一般是变化的信号，其幅值可能高于公共电极的参考电位，也可能低于公共电极的参考电位。也就是说，如果以公共电极的参考电位为基准，图像数据信号则包括具有正值的数据信号和具有负值的图像信号，而且，不同帧的图像的数据信号之间可能也是不同的，如图2所示。本申请的发明人认识到，对于具有正对幅值和负的幅值的变化的图像数据信号(例如，图2中的D+和D-)而言，公共电极电位(V-com)的理想值应具备以下特点：公共电极电位和正的数据信号D+之间的差值与公共电极电位 和负的数据信号D-之间的差值相等。但是，在实际生产实践中，尤其是在液晶显示面板的测试过程中，公共电极的电位很难维持上述的理想值。例如，如图2所示，实际的公共电极电位可能低于理想公共电极电位(例如，差值为n)，导致正的数据信号D+相对于参考电位的电位是(N+n)V，负的数据信号D-相对于参考电位的电位是(N-n)V。因此，当公共电极电位偏离上述理想值时，正的数据信号和负的数据信号将具有不同的绝对值，在点灯测试过程中会导致控制液晶分子偏转的电压不均衡，从而引发在液晶电容器之间发生电荷转移，在公共电极上存储电荷。随着测试过程中不同帧的图像被显示，这种电荷转移可能持续发生。因此，本申请人的发明人认识到，在已有的液晶显示面板测试过程中，公共电极上可能存储大量的电荷，这对液晶显示面板显示图像是不利的，会导致画面闪烁、黑白斑点等不良现象。
如果将本公开实施例提出的控制电路应用于液晶显示面板的测试过程，则可以减轻或缓解由于公共电极上存储大量电荷导致的显示画面不良的问题。控制电路中的电流触感器可以通过检测液晶显示面板的输入电流的变化而产生表明液晶显示面板所显示的图像帧发生切换的指示信号。放电信号生成电路接收到该指示信号后，会生成被提供至显示面板的放电信号。该放电信号可以例如由设置在显示面板上的放电控制电路接收，从而使得液晶显示面板的液晶电容器放电。因此，将本公开实施例提供的控制电路应用于液晶显示面板的测试过程，可以实现在显示不同帧的图像的时间段之间对液晶电容器施行一次放电过程。由此，可以避免在公共电极上聚集大量的电荷，提升液晶显示面板显示图像的质量。
能够理解到的是，液晶显示面板显示不同帧的图像所需要的电流是不同的，因此，通过检测液晶显示面板输入电流的变化可以判断所显示的图像帧是否发生切换。在一个实施例中，电流传感器被配置成检测到输入电流的变化幅度超过一个阈值(例如，10％)而产生指示信号，即，检测到输入电流的变化幅度超过该阈值被视为图像帧发生了切换，要显示下一帧的图像。由此，避免对图像帧切换的误检测。在实践中，电流传感器可以被设置在液晶显示面板的电源回路中。例如，电流传感器可以串联在向液晶显示面板提供工作电压的电源线路中。
在一个实施例中，电流传感器输出的指示信号是一个具有第一持 续时间的第一脉冲信号P1，放电信号是具有与第一持续时间相等的第二持续时间的第二脉冲信号P2，第二脉冲信号使得液晶电容器在所述第二持续时间内放电。也就是说，放电信号响应于指示信号而产生，并且也随着指示信号的结束而结束，这样，液晶电容器只是在发生图像帧切换的短时间内被放电，如此，可以避免或者降低对液晶显示面板正常显示图像的影响。
之前提到，用于控制显示面板中液晶电容器放电的放电控制电路可以设置在液晶显示面板中，但是，替代性地，放电控制电路也可以设置在控制电路中。如图3所示，控制电路10还包括放电控制电路103，放电控制电路响应于接收到来自于放电信号生成电路102的放电信号(即，第二脉冲信号P2)而使得液晶电容器放电。
图4示出了放电控制电路的示例，为了能够更清楚地理解液晶电容器的放电过程，图4也示意性地示出了液晶电容器C以及放电电路。如图4所示，液晶电容器的放电电路包括与其串联的放电开关(例如，TFT)，液晶电容器C的一端与像素开关(例如，TFT)电连接以接收数据信号data。放电控制电路103的示例包括处理器MCU和受处理器控制的电平选择电路103a。处理器MCU可与放电信号生成电路102电电连接以接收来自于放电信号生成电路的放电信号。在图4的示例中，电平选择电路103a包括串联电连接的第一晶体管T1和第二晶体管T2，第一晶体管用于接收高电平信号VH，第二晶体管用于接收低电平信号VL。在本公开的实施例中，高电平信号VH例如是具有恒定的幅值的正电位信号，例如，1.8V，3.3V等，低电平信号VL例如是零电位信号或者是具有恒定的幅值的负电位信号，例如-1.8V，-3.3V等。在处理器没有接收到来自于放电信号生成电路的放电信号时，其可以控制第一晶体管T1关断，而接通第二晶体管T2，从而向放电TFT的控制端输出低电平信号，放电TFT保持关断状态(在该示例中，放电TFT为N型TFT)。当处理器接收到来自于放电信号生成电路的放电信号时，其可以控制第一晶体管T1接通，第二晶体管T2关断，此时，放电TFT的控制端接收到高电平VH，放电TFT导通，实现对液晶电容器的放电。当然，图4仅仅示出了放电控制电路的示例，本领域技术人员基于本文揭示的原理可以设计出许多放电控制电路的替代方案，这些替代性方案都涵盖在本公开的精神范围之内，属于本申请的保护 范围。
下面，通过示例的方式说明放电信号生成电路的实施例。在一些实施例中，放电信号生成电路包括第二脉冲信号生成电路102b和第三脉冲信号生成电路102a，如图3所示，第三脉冲信号生成电路102a用于接收第一脉冲信号P1而生成第三脉冲信号P3，第二脉冲信号生成电路用于接收第三脉冲信号p3而生成所述第二脉冲信号P2，第三脉冲信号的第三持续时间与第一持续时间相等，第二脉冲信号的脉冲幅值大于第三脉冲信号的脉冲幅值。
在一个实施例中，如图5所示，第三脉冲信号生成电路包括光耦合器OP和第一电容器C1，光耦合器OP的输入端用于接收第一脉冲信号P1，第一电容器C1电连接至光耦合器的输出端，在光耦合器的输出端产生第二脉冲信号P2。对于图5所示的第三脉冲信号生成电路，能够理解到的是，当光耦合器OP的输入端没有接收到第一脉冲信号时，光耦合器的输出端与第一固定电平(例如，1.8V)信号接收端不连通，光耦合器的输出端不输出信号。当光耦合器OP的输入端接收到第一脉冲信号P1时，光耦合器的输出端与第一固定电平信号接收端连通而产生电压信号。电容器C1可随着第一脉冲信号P1的结束而放电，从而产生第三脉冲信号。能够理解到的是，可以对电容器C1所在的放电回路的电阻进行设计从而控制电容器C1的放电时间，使得第三脉冲信号的第三持续时间与第一持续时间相等。因此，在该示例中，第三脉冲信号的幅值大致为1.8V。
在一个实施例中，第二脉冲信号生成电路102b包括继电器及其驱动电路，如图6所示，驱动电路DR接收第三脉冲信号P3而驱动继电器RL输出第二脉冲信号P2。在图6的示例中，当驱动电路DR没有接收到第三脉冲信号P3时，继电器的输出端不与第二固定电平(例如，3.3V)信号接收端接通，当驱动电路DR接收到第三脉冲信号P3时，其控制继电器的输出端与第二固定电平信号接收端连通，使得从继电器的输出端输出第二固定电平信号。驱动电路DR可包括受控于第三脉冲信号P3的开关，当第三脉冲信号P3结束时，继电器的输出端也与第二固定电平信号接收端断开。在该示例中，第三脉冲信号的幅值为3.3V。
对于上述的包括第二脉冲信号生成电路102b和第三脉冲信号生成 电路102a的实施例，实际上将来自于电流传感器的指示信号转变为幅值较大的第二脉冲信号，而且，幅值较大的第二脉冲信号并不是直接对电流传感器输出的指示信号进行放大处理而得到的，第二脉冲信号响应于指示信号产生，但是其自身独立于电流传感器的指示信号，这对于提高放电控制电路响应于来自于电流传感器的指示信号而控制液晶电容器放电的准确性是有利的。
对于上文中提到的第一固定电平信号和第二固定电平信号，可以通过外部电路提供，也可以在控制电路内部实现。例如，控制电路可包括功率转换电路，该功率转换电路能够接收外部的电源电压而产生各种幅值的直流电压，例如，1.8V、3.3V，还可以产生供控制电路内部各个电路单元所需要的工作电压，在此不作详述。
如前所述，本公开的实施例提供的控制电路可以应用于液晶显示面板的测试过程，特别地，该控制电路可以控制液晶显示面板中的液晶电容器在测试过程中放电。因此，本公开的另一实施例提供了一种用于液晶显示面板的测试设备，其包括前述实施例中任一实施例所述的控制电路。如图7所示，液晶显示面板的测试设备包括前述实施例所述的控制电路10，该测试设备可以对制作完成的液晶显示面板进行测试，以提供产品的良率。测试设备可以以各种形式存在，例如测试设备可以是测试板的形式。
在一些实施例中，如图7所示，测试设备包括电压输入端口Vin和电压输出端口Vout，电压输入端口用于接收外部电压，电压输出端口用于向液晶显示面板提供工作电压以产生供电流传感器检测的输入电流，电流传感器可以电连接在电压输入端口和电压输出端口之间以检测输入电流的变化。进一步地，如图7所示，测试设备包括图像信号输出接口Dout，其用于与液晶显示面板电连接以向液晶显示面板提供图像信号。
利用本公开实施例提供的测试设备对液晶显示面板进行测试，可以在测试过程中对液晶显示面板中的液晶电容器进行短时间的放电，至少能够降低聚集在公共电极上的电荷。对于改进出厂后的液晶显示面板显示图像的质量是有益的，进一步提升产品的良率。
相应地，本公开的另外的实施例提供了一种用于液晶显示面板的测试方法，该测试方法中所述方法包括：向液晶显示面板提供图像信 号以进行图像显示；检测液晶显示面板的输入电流的变化以判断是否发生图像帧切换，响应于检测到发生图像帧切换，对液晶显示面板中由公共电极和像素电极构成的液晶电容器进行放电。
进一步地，在本公开实施例提供的测试方法中，可以使用电流传感器检测所述输入电流的变化并生成具有第一持续时间的第一脉冲信号，所述第一脉冲信号表明液晶显示面板所显示的图像帧的切换。测试方法可包括：响应于生成第一脉冲信号，生成具有与第一持续时间相等的第二持续时间的第二脉冲信号，所述第二脉冲信号使得液晶电容器在所述第二持续时间内放电。
在一些实施例中，液晶显示面板包括与液晶电容器串联的放电开关及放电控制电路，测试方法包括：将所述第二脉冲信号提供给所述放电控制电路，放电控制电路响应于接收到第二脉冲信号而接通所述放电开关。此时，液晶电容器可通过放电开关所在的放电回路在第二脉冲信号的持续时间内放电，从而减少或去除聚集在公共电极上的电荷。
在另一实施例中，测试方法还可包括：在生成所述第二脉冲信号之前，基于所述第一脉冲信号而生成第三脉冲信号，第三脉冲信号的第三持续时间与第一持续时间相等；基于所述第三脉冲信号生成所述第二脉冲信号，第二脉冲信号的脉冲幅值大于第三脉冲信号的脉冲幅值。
此外，本领域技术人员能够理解到的是，本文中提到的“相等”并不意味着一定是绝对相等，其含义还包括“近似相等”或“大致相等”。例如，考虑到信号延迟以及外部环境干扰等因素，第一脉冲信号的第一持续时间、第二脉冲信号的第二持续时间和第三脉冲信号的第三持续时间可能并不是绝对相等，例如，在一些实施例中，它们彼此之间可能存在毫秒级的差值。
本公开实施例提出的用于液晶显示面板的测试方法的实施例具有与前述的控制电路和测试设备的实施例相似的技术效果，在此不再赘述。
以上具体描述了本公开的一些示例性实施例，但是本领域技术人员在实践所要求保护的主题时根据对附图、公开内容已经权利要求的研究，能够理解和实现所公开实施例的其他变型。在权利要求中，词 语“包括”不排除其它元件的存在，且各项权利要求不对其中所记载的各技术特征的数量作出限制。虽然一些特征被记载在不同的从属权利要求中，但是本申请也意图涵盖将这些特征组合在一起的实施例。

Claims (15)

  1. 一种用于液晶显示面板的控制电路，液晶显示面板包括公共电极和像素电极，其中所述控制电路包括：
    电流传感器，用于检测所述液晶显示面板的输入电流的变化而产生指示信号，所述指示信号表明液晶显示面板所显示的图像帧的切换，
    放电信号生成电路，用于从所述电流传感器接收所述指示信号，并且所述放电信号生成电路响应于接收到所述指示信号而生成放电信号，使得液晶显示面板中由公共电极和像素电极构成的液晶电容器放电。
  2. 如权利要求1所述的控制电路，其中所述指示信号是具有第一持续时间的第一脉冲信号，所述放电信号是具有与第一持续时间相等的第二持续时间的第二脉冲信号，所述第二脉冲信号使得所述液晶电容器在所述第二持续时间内放电。
  3. 如权利要求2所述的控制电路，其中所述控制电路还包括放电控制电路，放电控制电路响应于接收到所述第二脉冲信号而使得所述液晶电容器放电。
  4. 如权利要求3所述的控制电路，其中放电控制电路包括处理器和电平选择电路，电平选择电路包括第一晶体管和第二晶体管，第一晶体管的第一端和第二晶体管的第二端电连接，第二晶体管的第二端用于接收高电平信号，第二晶体管的第一端用于接收低电平信号，第一晶体管和第二晶体管的控制端电电连接至所述处理器的输出端，处理器的输入端用于接收第二脉冲信号。
  5. 如权利要求2所述的控制电路，其中放电信号生成电路包括第二脉冲信号生成电路和第三脉冲信号生成电路，第三脉冲信号生成电路用于接收所述第一脉冲信号而生成第三脉冲信号，第二脉冲信号生成电路用于接收第三脉冲信号而生成所述第二脉冲信号，第三脉冲信号的第三持续时间与第一持续时间相等，第二脉冲信号的脉冲幅值大于第三脉冲信号的脉冲幅值。
  6. 如权利要求5所述的控制电路，其中第三脉冲信号生成电路包括光耦合器和第一电容器，所述光耦合器的输入端用于接收所述第一脉冲信号，第一电容器电连接至光耦合器的输出端。
  7. 如权利要求6所述的控制电路，其中第二脉冲信号生成电路包括继电器及其驱动电路，驱动电路接收所述第三脉冲信号而驱动所述继电器输出所述第二脉冲信号。
  8. 如权利要求1-7所述的控制电路，其中所述电流传感器响应于所述输入电流的变化幅度超过10％，而产生所述指示信号。
  9. 一种用于液晶显示面板的测试设备，包括权利要求1-8中任一项所述的控制电路。
  10. 如权利要求9所述的测试设备，其中测试设备包括电压输入端口和电压输出端口，电压输入端口用于接收外部电源电压，电压输出端口用于向液晶显示面板提供工作电压以产生所述输入电流，其中所述电流传感器电连接在电压输入端口和电压输出端口之间以检测所述输入电流的变化。
  11. 如权利要求10所述的测试设备，其中所述测试设备包括图像信号输出接口，其用于与液晶显示面板电连接以向液晶显示面板提供图像信号。
  12. 一种用于液晶显示面板的测试方法，液晶显示面板包括公共电极和像素电极，其中所述方法包括：
    向液晶显示面板提供图像信号以进行图像显示；
    检测液晶显示面板的输入电流的变化以判断是否发生图像帧切换；
    响应于检测到发生图像帧切换，对液晶显示面板中由公共电极和像素电极构成的液晶电容器进行放电。
  13. 如权利要求12所述的测试方法，其中所述方法包括：
    使用电流传感器检测所述输入电流的变化并生成具有第一持续时间的第一脉冲信号，所述第一脉冲信号表明发生图像帧切换，
    响应于生成第一脉冲信号，生成具有与第一持续时间相等的第二持续时间的第二脉冲信号，所述第二脉冲信号使得所述液晶电容器在所述第二持续时间内放电。
  14. 如权利要求13所述的测试方法，其中液晶显示面板包括与所述液晶电容器串联的放电开关及放电控制电路，所述方法包括：
    将所述第二脉冲信号提供给所述放电控制电路，放电控制电路响应于接收到第二脉冲信号而接通所述放电开关。
  15. 如权利要求14所述的测试方法，还包括：
    在生成所述第二脉冲信号之前，基于所述第一脉冲信号而生成第三脉冲信号，第三脉冲信号的第三持续时间与第一持续时间相等；
    基于所述第三脉冲信号生成所述第二脉冲信号，第二脉冲信号的脉冲幅值大于第三脉冲信号的脉冲幅值。
PCT/CN2018/120507 2018-03-27 2018-12-12 液晶显示面板的控制电路、测试设备和测试方法 WO2019184449A1 (zh)

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