WO2023070730A1 - 感测电路以及感测信号的侦测方法 - Google Patents

感测电路以及感测信号的侦测方法 Download PDF

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Publication number
WO2023070730A1
WO2023070730A1 PCT/CN2021/128954 CN2021128954W WO2023070730A1 WO 2023070730 A1 WO2023070730 A1 WO 2023070730A1 CN 2021128954 W CN2021128954 W CN 2021128954W WO 2023070730 A1 WO2023070730 A1 WO 2023070730A1
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WIPO (PCT)
Prior art keywords
sensing signal
signal
sub
sensing
display panel
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PCT/CN2021/128954
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English (en)
French (fr)
Inventor
陈志毅
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深圳市华星光电半导体显示技术有限公司
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Application filed by 深圳市华星光电半导体显示技术有限公司 filed Critical 深圳市华星光电半导体显示技术有限公司
Priority to US17/618,509 priority Critical patent/US20240038109A1/en
Publication of WO2023070730A1 publication Critical patent/WO2023070730A1/zh

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Classifications

    • 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
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
    • G06F3/042—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by opto-electronic means
    • 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
    • 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
    • G09G3/3674—Details of drivers for scan electrodes
    • G09G3/3677—Details of drivers for scan electrodes suitable for active matrices only
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2300/00—Aspects of the constitution of display devices
    • G09G2300/04—Structural and physical details of display devices
    • G09G2300/0421—Structural details of the set of electrodes
    • G09G2300/0426—Layout of electrodes and connections

Definitions

  • the present application relates to the field of display technology, in particular to a sensing circuit and a detection method for sensing signals.
  • the display panel With the advancement of science and technology, display panels integrated with light sensing functions are widely used in all aspects of life, work and study, bringing users more diverse and more convenient experience.
  • the display panel usually utilizes an on-glass technology to realize the light sensing function.
  • the in-plane photo sensor In-Cell photo sensor
  • the in-plane photo sensor has more advantages in cost and is conducive to mass production.
  • the parasitic capacitance generated between the fingers of the signal traces such as data lines
  • the sensing signal fed back by the photosensitive element generates crosstalk, which affects the detection accuracy of the sensing signal.
  • the present application provides a sensing circuit and a detection method of a sensing signal to solve the technical problem that the crosstalk caused by signal traces such as data lines affects the detection accuracy of the sensing signal during the sensing signal detection process.
  • the present application provides a detection method of a sensing signal, which includes:
  • the second frame picture display period signal reading is performed on the display panel to obtain a second sensing signal, and the display voltage polarity corresponding to the second frame picture display period is opposite to that of the first frame picture display period ;
  • a target sensing signal is generated according to the first sensing signal and the second sensing signal.
  • the step of performing signal reading on the display panel and obtaining the first sensing signal during the display period of the first frame includes:
  • the first sensing signal is generated according to the first sub-sensing signal and the second sub-sensing signal.
  • the step of generating the first sensing signal according to the first sub-sensing signal and the second sub-sensing signal includes:
  • the step of performing signal reading on the display panel during the second frame display period, and obtaining the second sensing signal includes:
  • the second sensing signal is generated according to the third sub-sensing signal and the fourth sub-sensing signal.
  • the step of generating the second sensing signal according to the third sub-sensing signal and the fourth sub-sensing signal includes:
  • the step of generating a target sensing signal according to the first sensing signal and the second sensing signal includes:
  • the display period of the first frame picture and the display period of the second frame picture are display periods of adjacent frame pictures.
  • the present application also provides a sensing signal detection method, which includes: within the first frame display period, read the first signal from the display panel to obtain the first sub-sensing signal, the first sub-sensing signal A sub-sensing signal includes a first noise signal; a second signal reading is performed on the display panel to obtain a second sub-sensing signal, and the second sub-sensing signal includes the first noise signal and the first noise signal. Photogenerated current; generating the first sensing signal according to the first sub-sensing signal and the second sub-sensing signal;
  • the first signal reading is performed on the display panel to obtain a third sub-sensing signal, and the third sub-sensing signal includes a second noise signal; and the display panel is read
  • the second signal reading is to obtain the fourth sub-sensing signal, the fourth sub-sensing signal includes the second noise signal and the second photo-generated current; according to the third sub-sensing signal and the fourth sub-sensing signal
  • the sub-sensing signal generates the second sensing signal;
  • a target sensing signal is generated according to the first sensing signal and the second sensing signal.
  • the step of generating the first sensing signal according to the first sub-sensing signal and the second sub-sensing signal includes:
  • the step of generating a target sensing signal according to the first sensing signal and the second sensing signal includes:
  • the display period of the first frame picture and the display period of the second frame picture are display periods of adjacent frame pictures.
  • the present application also provides a sensing circuit, which includes a photosensitive module and a detection module;
  • the signal reading lines are respectively electrically connected to the photosensitive module and the detection module, and the detection module is used to read the signal of the display panel through the photosensitive module in the first frame display period , to obtain the first sensing signal;
  • the second frame picture display period signal reading is performed on the display panel to obtain a second sensing signal, and the display voltage polarity corresponding to the second frame picture display period is opposite to that of the first frame picture display period ;
  • a target sensing signal is generated according to the first sensing signal and the second sensing signal.
  • the photosensitive module includes a photosensitive transistor, a switch transistor, and a sensing capacitor
  • the gate of the photosensitive transistor is connected to the first power supply voltage, the source of the photosensitive transistor is connected to the second power supply voltage, the drain of the photosensitive transistor, one end of the sensing capacitor and the source of the switching transistor
  • the poles are connected together, the gate of the switching transistor is connected to the scan signal, and the drain of the switching transistor is electrically connected to the signal reading line;
  • both the photosensitive transistor and the switching transistor are turned off; when the second signal reading is performed on the display panel, the photosensitive transistor is turned off, The switching transistor is turned on.
  • the detection module includes a sampling unit and a processing unit
  • the detection unit is used to obtain the first sensing signal and the second sensing signal through the signal reading line;
  • the processing unit is connected to the digital-to-analog converter and is used to process the first sensing signal A sensing signal and the second sensing signal are processed to generate a target sensing signal.
  • the processing unit is a field programmable gate array.
  • the sampling unit includes an amplifier, an integrating capacitor, a switching device, a correlated double sampling circuit, and an analog-to-digital converter;
  • the first input end of the amplifier is connected to a reference voltage
  • the second input end of the amplifier is electrically connected to the signal reading line
  • the output end of the amplifier is connected to the correlated double sampling circuit
  • the correlation The double sampling circuit is connected with the analog-to-digital converter.
  • the sensing circuit further includes a driving chip, and the processing unit outputs the target sensing signal to the driving chip.
  • the application provides a sensing circuit and a detection method of a sensing signal.
  • the detection method of the sensing signal includes: within the display period of the first frame, read the signal from the display panel to obtain the first sensing signal; within the display period of the second frame, read the signal from the display panel, Acquiring a second sensing signal; wherein, the polarity of the display voltage corresponding to the second frame display period is opposite to that of the first frame display period; generating a target sensing signal according to the first sensing signal and the second sensing signal.
  • the first sensing signal and the second sensing signal obtained through two detections are used to generate the target sensing signal.
  • the polarity of the display voltage corresponding to the display period of the first frame picture is opposite to that of the display period of the second frame picture, it can be
  • the crosstalk caused by different display voltage jumps in each frame display cycle to the sensing signal is improved, and the detection accuracy of the sensing signal is improved.
  • FIG. 1 is a schematic flow chart of a detection method for a sensing signal provided by the present application
  • Fig. 2 is a schematic flow chart of step 101 in Fig. 1;
  • Fig. 3 is a schematic flow chart of step 102 in Fig. 1;
  • FIG. 4 is a schematic diagram of the first principle of the sensing signal detection method provided by the present application.
  • FIG. 5 is a schematic diagram of the second principle of the sensing signal detection method provided by the present application.
  • FIG. 6 is a schematic structural diagram of a sensing circuit provided by the present application.
  • first and second are used for description purposes only, and cannot be interpreted as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features.
  • features defined as “first” and “second” may explicitly or implicitly include one or more of the features, and thus should not be construed as limiting the present application.
  • the application provides a sensing circuit and a sensing signal detection method, which will be described in detail below. It should be noted that the description order of the following embodiments is not intended to limit the preferred order of the embodiments of the present application.
  • the signal reading is performed on the display panel to obtain the first sensing signal. Then, within the display period of the second frame picture, signal reading is performed on the display panel to obtain a second sensing signal.
  • the polarity of the display voltage corresponding to the display period of the second frame is opposite to that of the display period of the first frame. Finally, a target sensing signal is generated according to the first sensing signal and the second sensing signal.
  • the display panel is a liquid crystal display panel. Since the liquid crystal molecules will be polarized under the driving of DC voltage and cause image sticking, the pixel driving signal adopts a method of alternating positive and negative polarity voltages to drive the liquid crystal molecules.
  • the signal reading line is adjacent to the data line, due to the jump of the display voltage on the data line, there will be a gap between the signal reading line and the data line.
  • the parasitic capacitance causes the charges on the signal reading line to be coupled and crosstalked, which affects the detection accuracy of the sensing signal.
  • the present application sets the display voltage polarities corresponding to the first frame display period and the second frame display period to be opposite, and performs signal reading on the display panel during the first frame display period and the second frame display period respectively. , to acquire the first sensing signal and the second sensing signal. Therefore, under normal circumstances, if the first sensing signal is subjected to crosstalk and the detection result is relatively small, the crosstalk received by the second sensing signal will cause the detection result to be relatively large. vice versa.
  • the target sensing signal is generated according to the first sensing signal and the second sensing signal acquired twice, which can improve the crosstalk caused by the different display voltage jumps in each frame of the picture display cycle, and improve the sensing signal. detection accuracy.
  • the display panel in this application can adopt frame inversion, row inversion or a combination of both driving architectures, as long as the polarity of the display voltages corresponding to the first frame display period and the second frame display period are guaranteed to be opposite.
  • the polarities of the display voltages corresponding to the display periods of two adjacent frames are opposite.
  • the driving structure of row inversion the polarity of the display voltage corresponding to each row of sub-pixels in each frame display period is reversed.
  • the detection method of the sensing signal provided by the present application is significantly improved for static images.
  • the detection method of the sensing signal provided by the present application can also improve the dynamic screen to a certain extent.
  • the sensing signal of the display panel is detected, and the acquired first sensing signal and second sensing signal may be the photogenerated current of the photosensitive element, the signal to be compensated for the pixel driving circuit, and other needs in the display panel.
  • the test signal and the like are not specifically limited in this application.
  • FIG. 1 is a schematic flow chart of a sensing signal detection method provided in the present application.
  • the detection method of the sensing signal specifically includes the following steps:
  • a photosensitive unit and a signal reading line can be arranged in the display panel.
  • the induced current generated by the photosensitive unit is read through the signal reading line, so as to obtain the first sensing signal.
  • the first sensing signal can be directly read in a one-time reading manner, so as to improve detection efficiency.
  • the first sensing signal can be obtained through secondary reading, so as to further improve the detection accuracy.
  • FIG. 2 is a schematic flowchart of step 101 in FIG. 1 .
  • Step 101 comprises the following steps:
  • the first sub-sensing signal is read through the signal reading line 13 to obtain the first noise signal and the first leakage current signal.
  • the first signal reading of the display panel can be directly performed by turning off the photosensitive unit, so that the obtained first sub-sensing signal does not include the photo-generated current to be detected.
  • a second signal reading is performed on the display panel to obtain a second sub-sensing signal.
  • the display panel is irradiated with light such as laser light, and the photosensitive unit generates a photogenerated current.
  • the second sensing signal includes the first noise signal, the first leakage current signal and the first photo-generated current.
  • the second signal reading can be performed on the display panel, so that the obtained second sub-sensing signal includes the first photo-generated current to be detected.
  • the obtained first sensing signal is the first light generated by the display panel after being irradiated by laser light.
  • the current eliminates the first noise signal and the first leakage current signal, thereby improving the signal-to-noise ratio.
  • the display voltage pole corresponding to the display period of the second frame picture and the display period of the first frame picture Sex is the opposite.
  • a photosensitive unit and a signal reading line can be arranged in the display panel.
  • the induced current generated by the photosensitive unit is read through the signal reading line, so as to obtain the second sensing signal.
  • the second sensing voltage can be obtained directly by one-time reading, so as to improve the efficiency of signal reading.
  • Step 102 comprises the following steps:
  • the third sub-sensing signal is read through the signal reading line 13 to obtain the second noise signal and the second leakage current signal.
  • the first signal reading of the display panel can be directly performed by turning off the photosensitive unit, so that the obtained third sub-sensing signal does not include the second photo-generated current to be detected.
  • a second signal reading is performed on the display panel to obtain a fourth sub-sensing signal.
  • the display panel is irradiated with light such as laser light, and the photosensitive unit generates a photogenerated current.
  • the fourth sub-sensing signal includes the second noise signal, the second leakage current signal and the second photo-generated current.
  • the second signal reading can be performed on the display panel, so that the acquired fourth sub-sensing signal includes the second photo-generated current to be detected.
  • step 1011 and step 1012 it can be seen from step 1011 and step 1012 that, taking the difference between the first sub-sensing signal and the second sub-sensing signal, the obtained first sensing signal is the photo-generated current generated after the display panel is irradiated by laser light, Noise signals and leakage current signals are eliminated, thereby improving the signal-to-noise ratio.
  • the first sensing signal and the second sensing signal may be averaged to obtain the target sensing signal. Therefore, the crosstalk caused by different display voltage jumps in each frame display cycle to the sensing signal is improved, and the detection accuracy of the sensing signal is improved.
  • FIG. 4 is a schematic diagram of the first principle of the sensing signal detection method provided by the present application.
  • FIG. 5 is a schematic diagram of the second principle of the sensing signal detection method provided by the present application.
  • the first signal reading and the second signal reading can be performed on the display panel under the control of the first sensing signal CDS1 and the second sensing signal CDS2 respectively.
  • the display panel displays a solid-color picture
  • the voltage values of the display voltage corresponding to the frame display picture are the same, therefore, in the first signal reading phase t1 and in the second signal reading phase t2, the display voltage jumps
  • the detection interference to the sensing signal can be canceled out.
  • a non-solid-color picture that is, when the gray scale of the display screen changes, the jumps of the display voltage are different in the first signal reading phase t1 and in the second signal reading phase t2. Therefore, the detection interference to the sensing signal may not be offset, resulting in an inaccurate detection result of the sensing signal.
  • the first sensing signal and the second sensing signal are respectively detected within two frame display periods.
  • the first sensing signal is acquired in the Nth frame display period
  • the second sensing signal is acquired in the N+1th frame display period. Since the Nth frame display period and the N+1th frame display period The corresponding display voltages have opposite polarities. Therefore, by taking the average value of the first sensing signal and the second sensing signal, the detection interference of the jump of the display voltage on the sensing signal can be canceled out.
  • the frequency of signal reading is not limited in this application.
  • the present application may perform signal reading in each frame display period, or may perform signal reading in a specific frame display period according to changes in actual needs. However, it is required that the polarities of the display voltages corresponding to the frame image display period corresponding to the first sensing signal and the second sensing signal are reversed.
  • the present application performs signal reading in each frame display period, and processes the sensing signals read in every two adjacent frame display periods to obtain target sensing signals. That is, the first frame picture display period and the second frame picture display period are adjacent frame picture display periods. That is, "frame a, frame b, frame b, frame c, frame b, frame c, etc.”, so as to ensure the reporting rate of signal reading and further improve the detection accuracy of sensing signals.
  • the step of performing the first signal reading on the display panel and the step of performing the second signal reading on the display panel are separated by multiple lines of pixel scanning time .
  • each row of photosensitive units can be arranged corresponding to multiple rows of sub-pixel units, and each row of photosensitive units shares a scanning signal with one row of sub-pixels. Then, when row scanning is performed, corresponding photosensitive units can be turned on at the same time to detect sensing signals. Therefore, multiple lines of pixel scanning time are separated between the first signal reading and the second signal reading of the display panel.
  • the time interval between the first signal reading and the second signal reading of the display panel can be determined according to the transmittance of the display panel and the processing rate of the sensing signal.
  • the present application also provides a sensing circuit, which detects the sensing signal by using the sensing signal detecting method described in any one of the above-mentioned embodiments.
  • a sensing circuit which detects the sensing signal by using the sensing signal detecting method described in any one of the above-mentioned embodiments.
  • FIG. 6 is a schematic structural diagram of a sensing circuit provided in the present application.
  • the sensing circuit 100 includes a data line 11 , a scanning line 12 , a signal reading line 13 , a photosensitive module 10 and a detection module 20 .
  • the data lines 11 and the scan lines 12 are intersected.
  • the data lines 11 are arranged parallel to and adjacent to the signal readout lines 13 .
  • the photosensitive module 10 is electrically connected to the detection module 20 through the signal reading line 13 .
  • the detection module 20 detects the photosensitive module 10 by using the detection method of the sensing signal described in any one of the above-mentioned embodiments, so as to obtain the target sensing signal.
  • each photosensitive module 10 can be arranged corresponding to a plurality of sub-pixel units. For example, every sub-pixel unit of 6 rows and 6 columns is correspondingly provided with a photosensitive module 10 . Of course, the present application is not limited thereto. Wherein, the photosensitive module 10 shares the same scanning line 12 with any row of sub-pixel units in the 6 rows of sub-pixel units. That is, the photosensitive module 10 and a row of sub-pixel units share the same scanning signal.
  • the pixel driving circuit 30 includes a control transistor T1, a storage capacitor C ST1 and a liquid crystal capacitor C LC .
  • the gate of the control transistor T1 is electrically connected to the corresponding scanning line 12 to receive the scanning signal.
  • the source of the control transistor T1 is electrically connected to the corresponding data line 11 to receive a data signal, that is, a display voltage.
  • the drain of the control transistor T1 is connected together with one end of the storage capacitor C ST1 and one end of the liquid crystal capacitor C LC .
  • the other end of the storage capacitor C ST1 and the other end of the liquid crystal capacitor C LC are both grounded.
  • the pixel driving circuit 30 in the embodiment of the present application is a 1T2C driving circuit, and its working principle is well-known to those skilled in the art, and will not be repeated here. It should be noted that the pixel driving circuit 30 provided in the present application is only an example, and should not be understood as a limitation to the present application.
  • the photosensitive module 10 includes a photosensitive transistor T2, a switch transistor T3, and a sensing capacitor C ST2 .
  • the gate of the photosensitive transistor T2 is connected to the first power supply voltage VGG.
  • the source of the photosensitive transistor T2 is connected to the second power supply voltage Bias.
  • the drain of the photosensitive transistor T2, one terminal of the sensing capacitor C ST2 and the source of the switching transistor T3 are connected together.
  • the gate of the switching transistor T3 is connected to the scan signal, and the drain of the switching transistor T3 is electrically connected to the signal reading line 13 .
  • the photosensitive module 10 in the embodiment of the present application is a driving circuit with a 2T1C structure.
  • the photosensitive module 10 has a photosensitive function such as laser light, and generates a photogenerated current.
  • the working sequence of the photosensitive module 10 includes a photosensitive stage and a signal reading stage. In the initial stage, under external light irradiation, the first power supply voltage VGG is applied to the gate of the phototransistor T2, the second power supply voltage Bias is applied to the drain of the phototransistor T2, and the phototransistor T2 is in an off state.
  • the photosensitive transistor T2 generates photocarriers under the action of light, and the corresponding photogenerated current flows from the photosensitive transistor T2 to the sensing capacitor C ST2 .
  • the photo-generated current flowing to the sensing capacitor C ST2 is stored in the sensing capacitor C ST2 to form electric energy correspondingly.
  • a scan signal is input to the gate of the switching transistor T3, and the switching transistor T3 is turned on.
  • the voltage of the sensing capacitor C ST2 is released from the drain of the switching transistor T3.
  • the signal readout line 13 reads out the photogenerated current flowing to the switching transistor T3.
  • the phototransistor T2 remains off.
  • the transistors used in this application can be thin film transistors or field effect transistors or other devices with the same characteristics. Since the source and drain of the transistors used here are symmetrical, their source and drain can be interchanged. In the embodiment of the present application, in order to distinguish the two poles of the transistor except the gate, one pole is called the source, and the other pole is called the drain. According to the form in the accompanying drawings, it is stipulated that the middle terminal of the switching transistor is the gate, the signal input terminal is the source terminal, and the output terminal is the drain terminal.
  • the transistors used in the embodiments of the present application may include P-type transistors and/or N-type transistors, wherein the P-type transistors are turned on when the gate is at a low level, and are turned off when the gate is at a high level, and the N-type transistors are turned on at the gate. Turns on when extremely high and turns off when gate is low.
  • the sensing circuit 100 can be used to read signals from the display panel twice.
  • the signal is read from the display panel for the first time, both the photosensitive transistor T2 and the switching transistor T3 are turned off.
  • the first sensing signal read through the signal reading line 13 includes noise signals and leakage current signals.
  • the photosensitive transistor T2 is turned off, and the switching transistor T3 is turned on.
  • the second sensing signal read through the signal reading line 13 includes a noise signal, a leakage current signal and a photogenerated current. Therefore, in each frame display period, the photogenerated current can be obtained by reading the signal twice from the display panel, which is equivalent to eliminating the noise signal and the leakage current signal, thereby improving the signal-to-noise ratio.
  • the switching transistor T3 in the photosensitive module 10 and the control transistor T1 in the pixel driving transistor 30 share a scanning signal. This setting enables the pixel driving circuit 30 and the photosensitive module 10 to be turned on simultaneously within the same row scanning time, so that the display panel can simultaneously read sensing signals when displaying images. This simplifies the signal routing within the display panel.
  • the detection module 20 includes a sampling unit 21 and a processing unit 22 .
  • the sampling unit 21 is used for acquiring the first sensing signal and the second sensing signal through the signal reading line 13 .
  • the processing unit 22 is connected with the sampling unit 21 and is used for processing the first sensing signal and the second sensing signal to generate a target sensing signal.
  • the sampling unit 21 includes an amplifier 211 , an integrating capacitor C FB , a switching device S1 , a correlated double sampling circuit (Correlated Double Sampling, CDS) 212 and an analog-to-digital converter (Analog-to-Digital Converter, ADC) 213 .
  • the first input terminal of the amplifier 21 is connected to the reference voltage Vref.
  • the second input end of the amplifier 21 is electrically connected to the signal reading line 13 .
  • the output of the amplifier 21 is connected to a correlated double sampling circuit CDS.
  • the correlated double sampling circuit CDS is connected to the analog-to-digital converter ADS.
  • the amplifier 211 is in the form of an integrator, and the amplifier 211 can be initialized by turning on the switch device S1. When the switch device S1 is turned off, the amplifier 211 starts to integrate the first sensing signal or the second sensing signal. The integrated voltage will be stored in the correlated double sampling circuit 212 . Sampling is then performed through the analog-to-digital converter 213 .
  • the amplifier 211 can be used to perform impedance matching on the first sensing signal or the second sensing signal on the signal reading line 13, thereby reducing the time when the signal on the signal reading line 13 is transmitted to the correlated double sampling circuit CDS. Distortion occurs, improve anti-interference ability.
  • the correlated double sampling circuit CDS is used to perform latching and logical operation on the signal output from the output terminal of the amplifier 211 to generate a voltage adopting signal.
  • the analog-to-digital converter ADC is used to digitize and output the voltage signal generated by the correlated double sampling circuit CDS, so as to obtain the target sensing signal.
  • the processing unit 22 may be a Field-Programmable Gate Array (Field-Programmable Gate Array, FPGA).
  • the FPGA processes the first sensing signal and the second sensing signal to obtain a target sensing signal.
  • the sensing circuit further includes a driving chip 40 , and the processing unit 22 outputs the processed target sensing signal to the driving chip 40 .
  • the driving chip 40 adjusts the driving voltage according to the received target sensing signal, so as to display corresponding patterns on the display screen of the display panel.
  • the present application provides a sensing circuit 100 .
  • the sensing circuit 100 includes a photosensitive module 10 , a signal reading line 13 and a detection module 20 .
  • the signal reading lines 13 are respectively connected to the photosensitive module 10 and the detection module 20 .
  • the detection module 20 utilizes the sensing signal detection method described in any one of the above embodiments to generate a target sensing signal through the signal reading line 13 . Therefore, the coupling effect of the display voltage on the data line 11 to the signal reading line 13 can be reduced, the stability of the output of the photo-generated current can be improved, and the detection accuracy and signal-to-noise ratio of the sensing signal can be improved.

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  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)

Abstract

本申请公开一种感测电路以及感测信号的侦测方法。该方法包括：在第一帧画面显示周期内，对显示面板进行信号读取，获取第一感测信号；在第二帧画面显示周期内，对显示面板进行信号读取，获取第二感测信号，第二帧画面显示周期与第一帧画面显示周期对应的显示电压极性相反；根据第一感测信号和第二感测信号生成目标感测信号。

Description

感测电路以及感测信号的侦测方法 技术领域
本申请涉及显示技术领域，具体涉及一种感测电路以及感测信号的侦测方法。
 背景技术
随着科学技术的进步，集成了光感应功能的显示面板被广泛应用于生活、工作和学习的各个方面，给用户带来了更多样、更便捷的使用体验。目前，显示面板通常利用外挂（On Glass）技术实现光感应功能。相较于外挂技术，面内光传感器（In-Cell photo sensor）在成本上更具优势，且利于量产。
 技术问题
但是，在In-Cell photo sensor技术中，由于将感光元件的相关电路与用于显示的器件及信号走线放置在一张光罩上，导致数据线等信号走线指间所产生的寄生电容对感光元件反馈的感测信号产生串扰，影响感测信号的侦测精度。
 技术解决方案
本申请提供一种感测电路以及感测信号的侦测方法，以解决在感测信号的侦测过程中，数据线等信号走线造成的串扰影响感测信号的侦测精度的技术问题。
本申请提供一种感测信号的侦测方法，其包括：
在第一帧画面显示周期内，对显示面板进行信号读取，获取第一感测信号；
在第二帧画面显示周期内，对所述显示面板进行信号读取，获取第二感测信号，所述第二帧画面显示周期与所述第一帧画面显示周期对应的显示电压极性相反；
根据所述第一感测信号和所述第二感测信号生成目标感测信号。
可选的，在本申请一些实施例中，所述在第一帧画面显示周期内，对显示面板进行信号读取，获取第一感测信号的步骤包括：
对所述显示面板进行第一次信号读取，获取第一子感测信号，所述第一子感测信号包括第一噪声信号；
对所述显示面板进行第二次信号读取，获取第二子感测信号，所述第二子感测信号包括所述第一噪声信号和第一光生电流；
根据所述第一子感测信号和所述第二子感测信号生成所述第一感测信号。
可选的，在本申请一些实施例中，所述对所述显示面板进行第一次信号读取的步骤与所述对所述显示面板进行第二次信号读取的步骤之间至少间隔一行像素扫描时间。
可选的，在本申请一些实施例中，所述根据所述第一子感测信号和所述第二子感测信号生成所述第一感测信号的步骤包括：
对所述第一子感测信号和所述第二子感测信号取差值，以得到所述第一感测信号。
可选的，在本申请一些实施例中，所述在第二帧画面显示周期内，对所述显示面板进行信号读取，获取第二感测信号的步骤包括：
对所述显示面板进行第一次信号读取，获取第三子感测信号，所述第三子感测信号包括第二噪声信号；
对所述显示面板进行第二次信号读取，获取第四子感测信号，所述第四子感测信号包括所述第二噪声信号和第二光生电流；
根据所述第三子感测信号和所述第四子感测信号生成所述第二感测信号。
可选的，在本申请一些实施例中，所述对所述显示面板进行第一次信号读取的步骤与所述对所述显示面板进行第二次信号读取的步骤之间至少间隔一行像素扫描时间。
可选的，在本申请一些实施例中，所述根据所述第三子感测信号和所述第四子感测信号生成所述第二感测信号的步骤包括：
对所述第三子感测信号和所述第四子感测信号取差值，以得到所述第二感测信号。
可选的，在本申请一些实施例中，所述根据所述第一感测信号和所述第二感测信号生成目标感测信号的步骤包括：
对所述第一感测信号和所述第二感测信号取平均值，以得到所述目标感测信号。
可选的，在本申请一些实施例中，所述第一帧画面显示周期与所述第二帧画面显示周期为相邻帧画面显示周期。
本申请还提供一种感测信号的侦测方法，其包括：在第一帧画面显示周期内，对所述显示面板进行第一次信号读取，获取第一子感测信号，所述第一子感测信号包括第一噪声信号；对所述显示面板进行第二次信号读取，获取第二子感测信号，所述第二子感测信号包括所述第一噪声信号和第一光生电流；根据所述第一子感测信号和所述第二子感测信号生成所述第一感测信号；
在第二帧画面显示周期内，对所述显示面板进行第一次信号读取，获取第三子感测信号，所述第三子感测信号包括第二噪声信号；对所述显示面板进行第二次信号读取，获取第四子感测信号，所述第四子感测信号包括所述第二噪声信号和第二光生电流；根据所述第三子感测信号和所述第四子感测信号生成所述第二感测信号；
根据所述第一感测信号和所述第二感测信号生成目标感测信号。
可选的，在本申请一些实施例中，所述对所述显示面板进行第一次信号读取的步骤与所述对所述显示面板进行第二次信号读取的步骤之间至少间隔一行像素扫描时间。
可选的，在本申请一些实施例中，所述根据所述第一子感测信号和所述第二子感测信号生成所述第一感测信号的步骤包括：
对所述第一子感测信号和所述第二子感测信号取差值，以得到所述第一感测信号。
可选的，在本申请一些实施例中，所述根据所述第一感测信号和所述第二感测信号生成目标感测信号的步骤包括：
对所述第一感测信号和所述第二感测信号取平均值，以得到所述目标感测信号。
可选的，在本申请一些实施例中，所述第一帧画面显示周期与所述第二帧画面显示周期为相邻帧画面显示周期。
相应的，本申请还提供一种感测电路，其包括感光模块和侦测模块；
所述信号读取线分别与所述感光模块以及所述侦测模块电性连接，所述侦测模块用于通过所述感光模块在第一帧画面显示周期内，对显示面板进行信号读取，获取第一感测信号；
在第二帧画面显示周期内，对所述显示面板进行信号读取，获取第二感测信号，所述第二帧画面显示周期与所述第一帧画面显示周期对应的显示电压极性相反；
根据所述第一感测信号和所述第二感测信号生成目标感测信号。
可选的，在本申请一些实施例中，所述感光模块包括感光晶体管、开关晶体管以及感测电容；
所述感光晶体管的栅极接入第一电源电压，所述感光晶体管的源极接入第二电源电压，所述感光晶体管的漏极、所述感测电容的一端以及所述开关晶体管的源极连接在一起，所述开关晶体管的栅极接入扫描信号，所述开关晶体管的漏极与所述信号读取线电性连接；
其中，在对所述显示面板进行第一次信号读取时，所述感光晶体管与所述开关晶体管均关闭；在对所述显示面板进行第二次信号读取时，所述感光晶体管关闭，所述开关晶体管打开。
可选的，在本申请一些实施例中，所述侦测模块包括取样单元和处理单元；
所述侦测单元用于通过所述信号读取线获取所述第一感测信号和所述第二感测信号；所述处理单元与所述数模转换器连接，并用于对所述第一感测信号和所述第二感测信号进行处理，以生成目标感测信号。
可选的，在本申请一些实施例中，所述处理单元为现场可编程门阵列。
可选的，在本申请一些实施例中，所述取样单元包括放大器、积分电容、开关器件、相关双取样电路以及模数转换器；
所述放大器的第一输入端接入参考电压，所述放大器的第二输入端与所述信号读取线电性连接，所述放大器的输出端与所述相关双取样电路连接，所述相关双取样电路与所述模数转换器连接。
可选的，在本申请一些实施例中，所述感测电路还包括驱动芯片，所述处理单元输出所述目标感测信号至所述驱动芯片。
 有益效果
本申请提供一种感测电路以及感测信号的侦测方法。感测信号的侦测方法包括：在第一帧画面显示周期内，对显示面板进行信号读取，获取第一感测信号；在第二帧画面显示周期内，对显示面板进行信号读取，获取第二感测信号；其中，第二帧画面显示周期与第一帧画面显示周期对应的显示电压极性相反；根据第一感测信号和所述第二感测信号生成目标感测信号。本申请通过两次侦测得到的第一感测信号和第二感测信号生成目标感测信号，由于第一帧画面显示周期与第二帧画面显示周期对应的显示电压极性相反，从而可以改善每帧画面显示周期的显示电压跳变不同对感测信号造成的串扰，提高感测信号的侦测精度。
 附图说明
为了更清楚地说明本申请实施例中的技术方案，下面将对实施例描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本申请的一些实施例，对于本领域技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获取其他的附图。
图1是本申请提供的感测信号的侦测方法的流程示意图；
图2是图1中步骤101的流程示意图；
图3是图1中步骤102的流程示意图；
图4是本申请提供的感测信号的侦测方法的第一原理示意图；
图5是本申请提供的感测信号的侦测方法的第二原理示意图；
图6是本申请提供的感测电路的结构示意图。
 本发明的实施方式
下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域技术人员在没有作出创造性劳动前提下所获取的所有其他实施例，都属于本申请保护的范围。
在本申请的描述中，需要理解的是，术语“第一”和“第二”仅用于描述目的，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量。由此，限定有“第一”和“第二”等的特征可以明示或者隐含地包括一个或者更多个所述特征，因此不能理解为对本申请的限制。
本申请提供一种感测电路以及感测信号的侦测方法，以下进行详细说明。需要说明的是，以下实施例的描述顺序不作为对本申请实施例优选顺序的限定。
在本申请提供的感测信号的侦测方法中，首先，在第一帧画面显示周期内，对显示面板进行信号读取，获取第一感测信号。然后，在第二帧画面显示周期内，对显示面板进行信号读取，获取第二感测信号。其中第二帧画面显示周期与第一帧画面显示周期对应的显示电压极性相反。最后，根据第一感测信号和第二感测信号生成目标感测信号。
可以理解的是，显示面板为液晶显示面板。由于液晶分子在直流电压驱动下会极化而引起影像残留，因此像素驱动信号采用正负极性电压交替法驱动液晶分子。在通过信号读取线对显示面板进行感测信号的侦测时，若信号读取线与数据线相邻，由于数据线上的显示电压跳变，信号读取线与数据线之间产生的寄生电容导致信号读取线上的电荷量受到耦合串扰，影响感测信号的侦测精确度。
对此，本申请通过设置第一帧画面显示周期和第二帧画面周期对应的显示电压极性相反，并在第一帧画面显示周期和第二帧画面周期内分别对显示面板进行信号读取，获取第一感测信号和第二感测信号。由此，通常情况下，若第一感测信号受到串扰导致侦测结果偏小，则第二感测信号受到的串扰会导致侦测结果偏大。反之亦然。由此，根据两次获取的第一感测信号和第二感测信号生成目标感测信号，可以改善每帧画面显示周期的显示电压跳变不同对感测信号造成的串扰，提高感测信号的侦测精度。
需要说明的是，本申请中的显示面板可以采用帧翻转、行翻转或两者结合的驱动架构，只要保证第一帧画面显示周期和第二帧画面周期对应的显示电压极性相反即可。其中，在帧翻转的驱动架构下，相邻两帧画面显示周期对应的显示电压极性相反。在行翻转的驱动架构下，每帧画面显示周期中每行子像素对应的显示电压极性相反。
在本申请中，由于静态显示画面的每帧显示画面周期对应的显示电压极性不同，但电压值不变。因此，本申请提供的感测信号的侦测方法对于静态画面改善显著。但是，在动态显示画面中，由于显示电压极性的变化，也会存在部分串扰，因此本申请提供的感测信号的侦测方法对于动态画面也有一定改善。
在本申请中，对显示面板的感测信号进行侦测，获取的第一感测信号和第二感测信号可以是感光元件的光生电流、像素驱动电路的待补偿信号、显示面板内其它需要测试的信号等，本申请对此不作具体限定。
本申请以下实施例均以第一感测信号和第二感测信号为感光元件的光生电流为例进行详细介绍，但不能理解为对本申请的限定。
请参阅图1，图1是本申请提供的感测信号的侦测方法的流程示意图。在本申请中，感测信号的侦测方法具体包括以下步骤：
101、在第一帧画面显示周期内，对显示面板进行信号读取，获取第一感测信号。
具体的，显示面板内可设置感光单元以及信号读取线。在第一帧画面显示周期内，通过信号读取线读取感光单元产生的感生电流，从而获取第一感测信号。
在一些实施例中，可通过一次读取的方式，直接读取得到第一感测信号，以提高侦测效率。
在另一些实施例中，可通过二次读取的方式获得第一感测信号，以进一步提高侦测准确度。具体的，请参阅图2，图2是图1中步骤101的流程示意图。步骤101包括以下步骤：
1011、对所述显示面板进行第一次信号读取，获取第一子感测信号，所述第一子感测信号包括第一噪声信号。
具体的，由于环境干扰、工艺差异等导致显示面板内不同的感光单元受到的噪声干扰以及产生的漏电流不同。则通过信号读取线13读取到第一子感测信号，以获取第一噪声信号以及第一漏电流信号。其中，可通过关闭感光单元，直接对显示面板进行第一次信号读取，以使得获取的第一子感测信号不包括待侦测的光生电流。
1012、对所述显示面板进行第二次信号读取，获取第二子感测信号，所述第二子感测信号包括所述第一噪声信号和第一光生电流；
具体的，在显示面板感光后，对显示面板进行第二次信号读取，获取第二子感测信号。此时，一方面，对显示面板进行激光等光照射，感光单元产生光生电流。同时，由于环境干扰、工艺差异等因素仍存在。因此，第二感测信号包括第一噪声信号、第一漏电流信号以及第一光生电流。其中，可通过打开感光单元，对显示面板进行第二次信号读取，以使得获取的第二子感测信号包括待侦测的第一光生电流。
1013、根据所述第一子感测信号和所述第二子感测信号获取所述第一感测信号。
具体的，由步骤1011和步骤1012可知，对第一子感测信号和第二子感测信号取差值，则得到的第一感测信号即为显示面板受到激光照射后产生的第一光生电流，消除了第一噪声信号与第一漏电流信号，从而提高了信噪比。
102、在第二帧画面显示周期内，对所述显示面板进行信号读取，获取第二感测信号，所述第二帧画面显示周期与所述第一帧画面显示周期对应的显示电压极性相反。
具体的，显示面板内可设置感光单元以及信号读取线。在第二帧画面显示周期内，通过信号读取线读取感光单元产生的感生电流，从而获取第二感测信号。
在一些实施例中，可通过一次读取的方式，直接读取得到第二感测电压，以提高信号读取的效率。
在另一些实施例中，可通过二次读取的方式获得第二感测信号，以进一步提高侦测准确度。请参阅图3，图3是图1中步骤102的流程示意图。步骤102包括以下步骤：
1021、对所述显示面板进行第一次信号读取，获取第三子感测信号，所述第三子感测信号包括第二噪声信号。
具体的，由于环境干扰、工艺差异等导致显示面板内不同的感光单元受到的噪声干扰以及产生的漏电流不同。则通过信号读取线13读取到第三子感测信号，以获取第二噪声信号以及第二漏电流信号。其中，可通过关闭感光单元，直接对显示面板进行第一次信号读取，以使得获取的第三子感测信号不包括待侦测的第二光生电流。
1022、对所述显示面板进行第二次信号读取，获取第四子感测信号，所述第四子感测信号包括所述第二噪声信号和第二光生电流。
具体的，在显示面板感光后，对显示面板进行第二次信号读取，获取第四子感测信号。此时，一方面，对显示面板进行激光等光照射，感光单元产生光生电流。同时，由于环境干扰、工艺差异等因素仍存在。因此，第四子感测信号包括第二噪声信号、第二漏电流信号以及第二光生电流。其中，可通过打开感光单元，对显示面板进行第二次信号读取，以使得获取的第四子感测信号包括待侦测的第二光生电流。
1023、根据所述第三子感测信号和所述第四子感测信号生成所述第二感测信号。
具体的，由步骤1011和步骤1012可知，对第一子感测信号和第二子感测信号取差值，则得到的第一感测信号即为显示面板受到激光照射后产生的光生电流，消除了噪声信号与漏电流信号，从而提高了信噪比。
103、根据所述第一感测信号和所述第二感测信号生成目标感测信号。
其中，可对第一感测信号和第二感测信号取平均值，以得到目标感测信号。从而改善每帧画面显示周期的显示电压跳变不同对感测信号造成的串扰，提高感测信号的侦测精度。
具体的，请参阅图4和图5，图4是本申请提供的感测信号的侦测方法的第一原理示意图。图5是本申请提供的感测信号的侦测方法的第二原理示意图。
如图4所示，在一帧画面显示周期内，可分别在第一感测信号CDS1和第二感测信号CDS2的控制下分别对显示面板进行第一次信号读取和第二次信号读取。具体的，当显示面板显示纯色画面时，帧显示画面对应的显示电压的电压值相同，因此，在第一次信号读取阶段t1以及在第二次信号读取阶段t2内，显示电压的跳变相同，对感测信号的侦测干扰可以相抵消。但是在显示非纯色画面，也即显示画面出现行灰阶变化时，在第一次信号读取阶段t1以及在第二次信号读取阶段t2内，显示电压的跳变存在不相同的情况，因此对感测信号的侦测干扰可以不能抵消，导致感测信号的侦测结果不准确。
如图5所示，本申请通过在两帧画面显示周期内分别侦测第一感测信号和第二感测信号。比如，在第N帧画面显示周期内获取第一感测信号，在第N+1帧画面显示周期内获取第二感测信号，由于第N帧画面显示周期和第N+1帧画面显示周期对应的显示电压极性相反，因此，通过对第一感测信号和第二感测信号取平均值，可以抵消显示电压的跳变对感测信号的侦测干扰。
需要说明的是，本申请对信号读取的频率不作限定。比如，本申请可在每一帧画面显示周期内均进行信号读取，也可以根据实际需求变化，在特定帧画面显示周期内进行信号读取。但均需满足第一感测信号和第二感测信号对应的帧画面显示周期的显示电压极性相反。
可选的，本申请在每一帧画面显示周期内均进行信号读取，且对每相邻两帧显示周期内读取的感测信号进行处理得到目标感测信号。即，第一帧画面显示周期与述第二帧画面显示周期为相邻帧画面显示周期。即“帧a帧b、帧b帧c、帧b帧c等”，从而保证信号读取的报点率，进一步提高感测信号的侦测精度。
在本申请一些实施例中，在每一帧画面显示周期内，对显示面板进行第一次信号读取的步骤与对显示面板进行第二次信号读取的步骤之间间隔多行像素扫描时间。
可以理解的是，在对显示面板进行第一次信号读取后，需要对获取的第一子感测信号进行处理。因此，对显示面板进行第一次信号读取和第二次信号读取之间需要间隔一定时间。此外，在显示面板中，每行感光单元可对应多行子像素单元设置，且每行感光单元与其中一行子像素共用扫描信号。则在进行行扫描时，可同时打开相应的感光单元进行感测信号的侦测。因此，对显示面板进行第一次信号读取和第二次信号读取之间间隔多行像素扫描时间。其中，对显示面板进行第一次信号读取和第二次信号读取的时间间隔可根据显示面板穿透率及感测信号处理速率决定。
相应的，本申请还提供一种感测电路，其采用上述任一实施例所述的感测信号的侦测方法进行感测信号的侦测，具体可参阅上述内容，在此不再赘述。
请参阅图6，图6是本申请提供的感测电路的一种结构示意图。感测电路100包括数据线11、扫描线12、信号读取线13、感光模块10以及侦测模块20。数据线11与扫描线12交叉设置。数据线11与信号读取线13平行且相邻设置。感光模块10通过信号读取线13与侦测模块20电性连接。侦测模块20利用上述任一实施例所述的感测信号的侦测方法对感光模块10进行侦测，以获取目标感测信号。
在本申请中，数据线11与扫描线12交叉限定出子像素单元（图中未标示）。子像素单元呈阵列排布。每一子像素单元均包括一像素驱动电路30。像素驱动电路30用于驱动子像素单元发光。其中，每一感光模块10可对应多个子像素单元设置。比如，每6行6列的子像素单元对应设置有一感光模块10。当然，本申请并不限于此。其中，感光模块10与6行子像素单元中的任意一行子像素单元共用同一条扫描线12。也即，感光模块10与一行子像素单元共用同一扫描信号。
具体的，像素驱动电路30包括控制晶体管T1、存储电容C ST1以及液晶电容C LC。其中，控制晶体管T1的栅极与相应的扫描线12电性连接，以接入扫描信号。控制晶体管T1的源极与相应的数据线11电性连接，以接入数据信号也即显示电压。控制晶体管T1的漏极与存储电容C ST1的一端以及液晶电容C LC的一端连接在一起。存储电容C ST1的另一端以及液晶电容C LC的另一端均接地。
本申请实施例中的像素驱动电路30为1T2C的驱动电路，其工作原理为本领域技术人员熟知的技术，在此不再赘述。需要说明的是，本申请提供的像素驱动电路30仅为示例，不能理解为对本申请的限定。
具体的，感光模块10包括感光晶体管T2、开关晶体管T3以及感测电容C ST2。其中，感光晶体管T2的栅极接入第一电源电压VGG。感光晶体管T2的源极接入第二电源电压Bias。感光晶体管T2的漏极、感测电容C ST2的一端以及开关晶体管T3的源极连接在一起。开关晶体管T3的栅极接入扫描信号，开关晶体管T3的漏极与信号读取线13电性连接。
本申请实施例中的感光模块10为2T1C结构的驱动电路。感光模块10具有激光等光感应功能，并产生光生电流。感光模块10的工作时序包括感光阶段和信号读取阶段。在初始阶段，在外界光照射下，向感光晶体管T2的栅极施加第一电源电压VGG，向感光晶体管T2的漏极施加第二电源电压Bias，感光晶体管T2处于关闭状态。感光晶体管T2在光照的作用下产生光生载流子，相应的光生电流由感光晶体管T2流向感测电容C ST2。流向感测电容C ST2的光生电流存储于感测电容C ST2对应形成电能。在信号读取阶段，开关晶体管T3的栅极输入扫描信号，打开开关晶体管T3。感测电容C ST2的电压从开关晶体管T3的漏极释放。信号读取线13读出流向开关晶体管T3的光生电流。在信号读取阶段中，感光晶体管T2仍保持关闭状态。
本申请中采用的晶体管可以为薄膜晶体管或场效应管或其他特性相同的器件，由于这里采用的晶体管的源极、漏极是对称的，所以其源极、漏极是可以互换的。在本申请实施例中，为区分晶体管除栅极之外的两极，将其中一极称为源极，另一极称为漏极。按附图中的形态规定开关晶体管的中间端为栅极、信号输入端为源极、输出端为漏极。此外本申请实施例所采用的晶体管可以包括P型晶体管和/或N型晶体管两种，其中，P型晶体管在栅极为低电平时导通，在栅极为高电平时截止，N型晶体管在栅极为高电平时导通，在栅极为低电平时截止。
进一步的，在每一帧画面显示周期内，可通过感测电路100对显示面板进行两次信号读取。在对显示面板进行第一次信号读取时，感光晶体管T2与开关晶体管T3均关闭。此时，由于环境干扰，以及工艺差异导致的晶体管漏电流不同，则通过信号读取线13读取到的第一感测信号包括噪声信号以及漏电流信号。在对显示面板进行第二次信号读取时，感光晶体管T2关闭，开关晶体管T3打开。此时，通过信号读取线13读取到的第二感测信号包括噪声信号、漏电流信号以及光生电流。因此，在每一帧画面显示周期内，通过对显示面板进行两次信号读取，可得到光生电流，相当于消除了噪声信号与漏电流信号，从而提高信噪比。
此外，感光模块10中的开关晶体管T3与像素驱动晶体管30中的控制晶体管T1共用扫描信号。该设置使得像素驱动电路30和感光模块10能够在同一行扫描时间内同时开启，使得显示面板在进行画面显示时，可以同步进行感测信号的读取。从而简化了显示面板内的信号走线。
在本申请中，侦测模块20包括取样单元21和处理单元22。取样单元21用于通过信号读取线13获取第一感测信号和所述第二感测信号。处理单元22与取样单元21连接，并用于对第一感测信号和第二感测信号进行处理，以生成目标感测信号。
其中，取样单元21包括放大器211、积分电容C FB、开关器件S1、相关双取样电路（Correlated Double Sampling, CDS）212以及模数转换器（Analog-to-Digital Converter, ADC）213。放大器21的第一输入端接入参考电压Vref。放大器21的第二输入端与信号读取线13电性连接。放大器21的输出端与相关双取样电路CDS连接。相关双取样电路CDS与模数转换器ADS连接。
其中，当感光单元20通过信号读取线13读取到第一感测信号或第二感测信号时。放大器211为积分器形式，透过开关器件S1的导通，可将放大器211初始化。当开关器件S1断开时，放大器211开始对第一感测信号或第二感测信号进行积分处理。积分后的电压会被存入相关双取样电路212。再透过模数转换器213进行采样。
在本申请中，放大器211可用于对信号读取线13上的第一感测信号或第二感测信号进行阻抗匹配，从而减少信号读取线13上的信号传输至相关双取样电路CDS时发生的失真，提高抗干扰的能力。此外，相关双取样电路CDS用于对放大器211的输出端输出的信号进行锁存以及逻辑运算以产生一电压采用信号。模数转换器ADC用于对相关双取样电路CDS所产生的电压采用信号进行数字量化并进行输出，从而得到目标感测信号。
在本申请中，处理单元22可以是现场可编程门阵列（Field-Programmable Gate Array, FPGA）。FPGA对第一感测信号和第二感测信号进行处理，以得到目标感测信号。此外，感测电路还包括驱动芯片40，处理单元22将处理后的目标感测信号输出至驱动芯片40。驱动芯片40根据接收到的目标感测信号调整驱动电压，从而在显示面板的显示画面中显示相应的图案。
本申请提供一种感测电路100。感测电路100包括感光模块10、信号读取线13以及侦测模块20。信号读取线13分别与感光模块10以及侦测模块20连接。侦测模块20利用上述任一实施例所述的感测信号的侦测方法，通过信号读取线13生成目标感测信号。从而可以降低数据线11上的显示电压对信号读取线13的耦合作用，提高光生电流输出的稳定性，从而提高感测信号的侦测精度和信噪比。
以上对本申请实施例进行了详细介绍，本文中应用了具体个例对本申请的原理及实施方式进行了阐述，以上实施例的说明只是用于帮助理解本申请的方法及其核心思想；同时，对于本领域的一般技术人员，依据本申请的思想，在具体实施方式及应用范围上均会有改变之处，综上所述，本说明书内容不应理解为对本申请的限制。

Claims (20)

  1. 一种感测信号的侦测方法，其包括：
    在第一帧画面显示周期内，对显示面板进行信号读取，获取第一感测信号；
    在第二帧画面显示周期内，对所述显示面板进行信号读取，获取第二感测信号，所述第二帧画面显示周期与所述第一帧画面显示周期对应的显示电压极性相反；
    根据所述第一感测信号和所述第二感测信号生成目标感测信号。
  2. 根据权利要求1所述的感测信号的侦测方法，其中，所述在第一帧画面显示周期内，对显示面板进行信号读取，获取第一感测信号的步骤包括：
    对所述显示面板进行第一次信号读取，获取第一子感测信号，所述第一子感测信号包括第一噪声信号；
    对所述显示面板进行第二次信号读取，获取第二子感测信号，所述第二子感测信号包括所述第一噪声信号和第一光生电流；
    根据所述第一子感测信号和所述第二子感测信号生成所述第一感测信号。
  3. 根据权利要求2所述的感测信号的侦测方法，其中，所述对所述显示面板进行第一次信号读取的步骤与所述对所述显示面板进行第二次信号读取的步骤之间至少间隔一行像素扫描时间。
  4. 根据权利要求2所述的感测信号的侦测方法，其中，所述根据所述第一子感测信号和所述第二子感测信号生成所述第一感测信号的步骤包括：
    对所述第一子感测信号和所述第二子感测信号取差值，以得到所述第一感测信号。
  5. 根据权利要求1所述的感测信号的侦测方法，其中，所述在第二帧画面显示周期内，对所述显示面板进行信号读取，获取第二感测信号的步骤包括：
    对所述显示面板进行第一次信号读取，获取第三子感测信号，所述第三子感测信号包括第二噪声信号；
    对所述显示面板进行第二次信号读取，获取第四子感测信号，所述第四子感测信号包括所述第二噪声信号和第二光生电流；
    根据所述第三子感测信号和所述第四子感测信号生成所述第二感测信号。
  6. 根据权利要求5所述的感测信号的侦测方法，其中，所述对所述显示面板进行第一次信号读取的步骤与所述对所述显示面板进行第二次信号读取的步骤之间至少间隔一行像素扫描时间。
  7. 根据权利要求5所述的感测信号的侦测方法，其中，所述根据所述第三子感测信号和所述第四子感测信号生成所述第二感测信号的步骤包括：
    对所述第三子感测信号和所述第四子感测信号取差值，以得到所述第二感测信号。
  8. 根据权利要求1所述的感测信号的侦测方法，其中，所述根据所述第一感测信号和所述第二感测信号生成目标感测信号的步骤包括：
    对所述第一感测信号和所述第二感测信号取平均值，以得到所述目标感测信号。
  9. 根据权利要求1所述的感测信号的侦测方法，其中，所述第一帧画面显示周期与所述第二帧画面显示周期为相邻帧画面显示周期。
  10. 一种感测信号的侦测方法，其包括：
    在第一帧画面显示周期内，对所述显示面板进行第一次信号读取，获取第一子感测信号，所述第一子感测信号包括第一噪声信号；对所述显示面板进行第二次信号读取，获取第二子感测信号，所述第二子感测信号包括所述第一噪声信号和第一光生电流；根据所述第一子感测信号和所述第二子感测信号生成所述第一感测信号；
    在第二帧画面显示周期内，对所述显示面板进行第一次信号读取，获取第三子感测信号，所述第三子感测信号包括第二噪声信号；对所述显示面板进行第二次信号读取，获取第四子感测信号，所述第四子感测信号包括所述第二噪声信号和第二光生电流；根据所述第三子感测信号和所述第四子感测信号生成所述第二感测信号；
    根据所述第一感测信号和所述第二感测信号生成目标感测信号。
  11. 根据权利要求10所述的感测信号的侦测方法，其中，所述对所述显示面板进行第一次信号读取的步骤与所述对所述显示面板进行第二次信号读取的步骤之间至少间隔一行像素扫描时间。
  12. 根据权利要求10所述的感测信号的侦测方法，其中，所述根据所述第一子感测信号和所述第二子感测信号生成所述第一感测信号的步骤包括：
    对所述第一子感测信号和所述第二子感测信号取差值，以得到所述第一感测信号。
  13. 根据权利要求10所述的感测信号的侦测方法，其中，所述根据所述第一感测信号和所述第二感测信号生成目标感测信号的步骤包括：
    对所述第一感测信号和所述第二感测信号取平均值，以得到所述目标感测信号。
  14. 根据权利要求10所述的感测信号的侦测方法，其中，所述第一帧画面显示周期与所述第二帧画面显示周期为相邻帧画面显示周期。
  15. 一种感测电路，其包括感光模块和侦测模块；
    所述感光模块与所述侦测模块连接，所述侦测模块用于通过所述感光模块在第一帧画面显示周期内，对显示面板进行信号读取，获取第一感测信号；
    在第二帧画面显示周期内，对所述显示面板进行信号读取，获取第二感测信号，所述第二帧画面显示周期与所述第一帧画面显示周期对应的显示电压极性相反；
    根据所述第一感测信号和所述第二感测信号生成目标感测信号。
  16. 根据权利要求15所述的感测电路，其中，所述感光模块包括感光晶体管、开关晶体管以及感测电容；
    所述感光晶体管的栅极接入第一电源电压，所述感光晶体管的源极接入第二电源电压，所述感光晶体管的漏极、所述感测电容的一端以及所述开关晶体管的源极连接在一起，所述开关晶体管的栅极接入扫描信号，所述开关晶体管的漏极与所述侦测模块连接；
    其中，在对所述显示面板进行第一次信号读取时，所述感光晶体管与所述开关晶体管均关闭；在对所述显示面板进行第二次信号读取时，所述感光晶体管关闭，所述开关晶体管打开。
  17. 根据权利要求15所述的感测电路，其中，所述侦测模块包括取样单元和处理单元；
    所述取样单元与所述感光模块连接，并用于获取所述第一感测信号和所述第二感测信号；所述处理单元与所述取样单元连接，并用于对所述第一感测信号和所述第二感测信号进行处理，以生成目标感测信号。
  18. 根据权利要求17所述的感测电路，其中，所述处理单元为现场可编程门阵列。
  19. 根据权利要求17所述的感测电路，其中，所述取样单元包括放大器、积分电容、开关器件、相关双取样电路以及模数转换器；
    所述放大器的第一输入端接入参考电压，所述放大器的第二输入端与所述信号读取线电性连接，所述放大器的输出端与所述相关双取样电路连接，所述相关双取样电路与所述模数转换器连接。
  20. 根据权利要求17所述的感测电路，其中，所述感测电路还包括驱动芯片，所述处理单元输出所述目标感测信号至所述驱动芯片。
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