Driving circuit and driving method of display panel and display device

Abstract

The invention provides a driving circuit and a driving method of a display panel and a display device.The driving circuit of the display panel comprises a row scanning circuit and a sampling circuit, the row scanning circuit outputs row opening signals to multiple rows of scanning lines row by row so as to open thin film transistors of all rows row by row, and the sampling circuit is connected with the sampling circuit; when the photosensitive element receives an optical signal and outputs a current signal, the current signal is output to the sampling circuit through the corresponding thin film transistor in the output time period of the row opening signal, and in order to avoid error sampling, the sampling circuit samples the current signal output by each column of data line in a preset time period in the output time period of the row opening signal. Therefore, the pulse level generated by coupling is effectively avoided, and the effective current signal is sampled, so that the touch point is accurately judged, and the touch accuracy and reliability are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical touch control, and in particular relates to a driving circuit, a driving method and a display device of a display panel. Background Art

[0002] In today's education field, vivid classroom experiments are becoming increasingly important in order to improve teaching effectiveness and student participation. Traditional experimental teaching methods are often subject to many restrictions, and the emergence of simulation software has brought new possibilities for classroom experiments. In this context, the optical touch solution came into being. It can achieve the touch effect by illuminating the display panel with a laser pen, which brings a more flexible and convenient operation method to teaching and has a wider range of applications.

[0003] However, a series of problems have emerged in the actual use of the optical touch solution. Among them, the touch position is erratic, and even ghost spots appear, which seriously affects the user experience. This has greatly hindered the promotion and application of the optical touch solution in the field of education.

[0004] One of the reasons is that the scanning lines and data lines of the display panel will cause parasitic capacitance Cgs to be formed between the control end and the output end of the display panel. Figure 3 When the row scan signal changes from low to high or from high to low, the data line is coupled by the row scan signal to generate a pulse level. When data is collected, the pulse level may be collected incorrectly, causing places that were not illuminated by the laser pen to be judged as being illuminated, resulting in abnormal touch points and false touches. Summary of the invention

[0005] The present invention aims to provide a driving circuit for a display panel, aiming to solve the problem of false touch caused by pulse level in a conventional display panel.

[0006] A first aspect of an embodiment of the present invention provides a driving circuit of a display panel, wherein the display panel includes a photosensitive array, the photosensitive array includes photosensitive units arranged in an array, multiple rows of scan lines, and multiple columns of data lines, the photosensitive units include photosensitive elements and thin film transistors, the photosensitive elements are connected to input ends of the thin film transistors, a row of the scan lines is connected to control ends of the thin film transistors of a row of the photosensitive units, a column of the data lines is connected to output ends of the thin film transistors of a column of the photosensitive units, and the photosensitive elements are used to receive light signals and convert output current signals;

[0007] The driving circuit of the display panel comprises:

[0008] A row scanning circuit connected to the plurality of rows of scanning lines, and used for outputting row-on signals to the plurality of rows of scanning lines row by row, so as to turn on the thin film transistors of each row row by row;

[0009] A sampling circuit is connected to the multiple columns of data lines and is used to sample the current signals output by each column of data lines during a preset time period within the output time period of each row start signal, wherein a first critical time point of the preset time period lags behind a time point of a rising edge of the row start signal, a second critical time point of the preset time period precedes a time point of a falling edge of the row start signal, and the first critical time point precedes the second critical time point.

[0010] Optionally, the driving circuit of the display panel further includes:

[0011] The control processing circuit is connected to the row scanning circuit and the sampling circuit respectively, and is used for:

[0012] Outputting a row control signal to control the row scanning circuit to output the row start signal row by row;

[0013] A current sampling signal output by the sampling circuit is acquired during a preset period within each output period of the row start signal or after each frame ends, and a touch state of the display panel is determined based on the current sampling signal.

[0014] Optionally, the sampling circuit includes:

[0015] A plurality of current-to-voltage circuits are connected to the plurality of data lines one by one, respectively, and the current-to-voltage circuits are used to convert the current signal into a voltage signal;

[0016] The analog-to-digital converter is connected to the plurality of current-to-voltage circuits and is used to convert the voltage signal into a digital signal during a preset period within an output period of each row-on signal.

[0017] Optionally, the current-to-voltage circuit comprises a resistor, a first end of the resistor is connected to the data line to form a signal output end of the current-to-voltage circuit, and a second end of the resistor is grounded.

[0018] Optionally, a time difference ΔT between a first critical time point of the preset time period and a time point of a rising edge of the row start signal, wherein ΔT is greater than or equal to 5*R*C;

[0019] Wherein, R is the resistance value of the resistor, and C is the parasitic capacitance between the gate and source of the thin film transistor.

[0020] Optionally, the current-to-voltage circuit further includes a capacitor, a first end of the capacitor is connected to the first end of the resistor, and a second end of the capacitor is grounded.

[0021] Optionally, the driving circuit further includes:

[0022] A plurality of voltage compensation circuits are connected to the plurality of data lines one by one, respectively, and output a negative voltage between the rising edge of the row start signal and the initial time point of the preset period, and the negative voltage gradually decreases within the ΔT.

[0023] A second aspect of an embodiment of the present invention provides a display device, including a display panel and a driving circuit of the display panel as described above, wherein the driving circuit of the display panel is connected to the display panel.

[0024] Optionally, the photosensitive element is a photosensitive transistor, and the display panel also includes a first power line and a second power line, the first power line is respectively connected to the first end of each photosensitive transistor, the second power line is respectively connected to the control end of each photosensitive transistor, the second end of the photosensitive transistor constitutes the signal output end of the photosensitive element, the first power line is used to input a first power signal, and the second power line is used to input a second power signal.

[0025] A third aspect of an embodiment of the present invention provides a method for driving a display panel, wherein the display panel includes a photosensitive array, the photosensitive array includes photosensitive units arranged in an array, multiple rows of scan lines, and multiple columns of data lines, the photosensitive units include photosensitive elements and thin film transistors, the photosensitive elements are connected to input ends of the thin film transistors, a row of the scan lines is connected to control ends of the thin film transistors of a row of the photosensitive units, a column of the data lines is connected to output ends of the thin film transistors of a column of the photosensitive units, and the photosensitive elements are used to receive light signals and convert output current signals;

[0026] The driving method of the display panel includes:

[0027] Outputting row-on signals to the scan lines row by row to turn on the thin film transistors in each row row by row;

[0028] The current signal output by each column data line is sampled during a preset time period within the output time period of each row start signal, the first critical time point of the preset time period lags behind the time point of the rising edge of the row start signal, the second critical time point of the preset time period is ahead of the time point of the falling edge of the row start signal, and the first critical time point is ahead of the second critical time point.

[0029] Compared with the prior art, the embodiments of the present invention have the following beneficial effects: the driving circuit of the above-mentioned display panel includes a row scanning circuit and a sampling circuit, the row scanning circuit outputs row start signals to multiple row scanning lines row by row, so as to turn on the thin film transistors of each row row by row, and when the photosensitive element receives the light signal and outputs the current signal, the current signal is output to the sampling circuit through the corresponding thin film transistor during the output period of the row start signal. In order to avoid missampling, the sampling circuit samples the current signal output by each column data line during a preset period within the output period of the row start signal, thereby effectively avoiding the pulse level generated by coupling and sampling a valid current signal, thereby accurately judging the touch point and improving the touch accuracy and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0031] Figure 1 A schematic diagram of the structure of a display device provided in Embodiment 1 and Embodiment 4 of the present invention;

[0032] Figure 2 A schematic diagram of the structure of a display panel provided in Embodiment 1 of the present invention;

[0033] Figure 3 A schematic diagram of the waveforms of the row scanning signal and the pulse level provided in the first embodiment of the present invention;

[0034] Figure 4 A schematic diagram of a first structure of a driving circuit provided in Embodiment 1 of the present invention;

[0035] Figure 5 A schematic diagram of a readout timing of a driving circuit provided in Embodiment 1 of the present invention;

[0036] Figure 6 A second structural schematic diagram of the driving circuit provided in the first embodiment of the present invention;

[0037] Figure 7 A third structural schematic diagram of the driving circuit provided in the first embodiment of the present invention;

[0038] Figure 8 A schematic diagram of the structure of a sampling circuit provided in Embodiment 1 of the present invention;

[0039] Fig. 9 A circuit diagram of a sampling circuit and a control processing circuit provided in Embodiment 2 of the present invention;

[0040] Fig.10 A schematic diagram of signal waveforms of a driving circuit provided in Embodiment 2 of the present invention;

[0041] Fig.11 A schematic diagram of a sampling process of a processor provided in Embodiment 2 of the present invention;

[0042] Fig.12 A schematic diagram of the structure of a driving circuit provided in Embodiment 2 of the present invention;

[0043] Fig.13 A schematic diagram of the structure of a driving circuit provided in Embodiment 3 of the present invention;

[0044] Fig.14 A schematic diagram of a process flow of a driving method provided in Embodiment 5 of the present invention;

[0045] Among them, the reference numerals in the figures are:

[0046] 1. Display device; 100. Display panel; 200. Driving circuit; 110. Photosensitive unit; 120. Second power line; 130. First power line; 111. Photosensitive element; 210. Line scanning circuit; 220. Sampling circuit; 230. Control processing circuit; 221. Current-to-voltage circuit; 222. Analog-to-digital converter; 240. Voltage compensation circuit; 231. Processor; 232. Digital-to-analog converter; 233. Comparison circuit;

[0047] TFT1, thin film transistor; TFT2, photosensitive transistor; Cgs, parasitic capacitance; G, scan line; S, data line; R1, resistor; C1, capacitor; U1, operational amplifier; R2, second resistor; R3, third resistor; U2, comparator;

[0048] VGH, row-on signal; VGL, row-off signal; T1, output period; T2, preset period; t1, time point of rising edge; t2, time point of falling edge; t3, first critical time point; t4, second critical time point. DETAILED DESCRIPTION

[0049] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0050] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0051] Embodiment 1

[0052] A first aspect of an embodiment of the present invention provides a driving circuit 200 of a display panel 100, such as Figure 1 As shown, the driving circuit 200 is connected to the display panel 100 and is used to perform line scanning on the display panel 100. The display panel 100 converts the detected optical signal into an electrical signal and outputs it to the driving circuit 200. The driving circuit 200 determines the touch position of the optical signal based on the received electrical signal, thereby controlling the display panel 100 to display corresponding image information or switch display modes, switch display interfaces, turn on and off the computer, and other operations.

[0053] like Figure 2 As shown, the display panel 100 includes a photosensitive array, which includes photosensitive units 110 arranged in an array, multiple rows of scan lines G and multiple columns of data lines S. Multiple photosensitive units 110 in each row are connected to the same row of scan lines G, and multiple photosensitive units 110 in each column are connected to the same column of data lines S. The multiple rows of scan lines G input row start signals VGH row by row. When the row start signal VGH of each row is output to the multiple photosensitive units 110 in the same row, the photosensitive units 110 in each column of the row are turned on and enter a photosensitive mode. When one or more photosensitive units 110 in the row receive a laser pulse, the photosensitive unit 110 converts the laser pulse into an electrical signal and outputs it through the connected data line S. The driving circuit 200 determines the position of the optical touch according to the time of the output row start signal and the position of the data line S where the received electrical signal is located, thereby controlling the display panel 100 to display corresponding image information or switch display modes, switch display interfaces, turn on and off the machine, and other operations.

[0054] The photosensitive unit 110 may include a photosensitive element 111 and a corresponding switch tube, such as Figure 2 As shown, in an optional embodiment, the photosensitive unit 110 includes a photosensitive element 111 and a thin film transistor TFT1, the photosensitive element 111 is connected to the input end of the thin film transistor TFT1, a row of scan lines G is connected to the control end of the thin film transistor TFT1 of a row of photosensitive units 110, a column of data lines S is connected to the output end of the thin film transistor TFT1 of a column of photosensitive units 110, and the photosensitive element 111 is used to receive light signals and convert output current signals.

[0055] The multiple scanning lines G input the row start signal VGH row by row. When the row start signal VGH of each row is output to the multiple photosensitive units 110 in the same row, the photosensitive units in each column of the row are turned on and enter the photosensitive mode, wherein the optical signal is mainly the laser pulse of the laser pen. When one or more photosensitive elements 111 in the row receive the laser pulse, the photosensitive element 111 performs photoelectric conversion. The photosensitive element 111 converts the laser pulse into a current signal. When the thin film transistor TFT1 connected to the photosensitive element 111 is turned on, the current signal flows out to the data line S through the thin film transistor TFT1 and is transmitted to the driving circuit 200. The driving circuit 200 determines the position of the optical touch according to the time of the output row start signal and the position of the data line where the received electrical signal is located, thereby controlling the display panel 100 to display the corresponding image information or switch the display mode, switch the display interface, turn on and off the machine, and other operations.

[0056] Among them, the photosensitive element 111 can adopt photosensitive structures such as photodiodes and photosensitive transistors TFT2. In an optional embodiment, the photosensitive element 111 is a photosensitive transistor TFT2, and the display panel 100 also includes a first power line 130 and a second power line 120. The first power line 130 is respectively connected to the first end of each photosensitive transistor TFT2, and the second power line 120 is respectively connected to the control end of each photosensitive transistor TFT2. The second end of the photosensitive transistor TFT2 constitutes the signal output end of the photosensitive element 111. The first power line 130 is used to input a first power signal VD, and the second power line 120 is used to input a second power signal VG.

[0057] The first power line 130 provides a first power signal VD to the first end of the photosensitive transistor TFT2 for providing a driving power supply. The second power line 120 provides a second power signal VG to the control end of the photosensitive transistor TFT2 for controlling the conduction of the photosensitive transistor TFT2. After receiving the laser pulse, the internal impedance of the photosensitive transistor TFT2 changes, and the ratio of the first power signal VD to the internal impedance changes, that is, the magnitude of its own current changes. The converted current signal is output to the connected thin film transistor TFT1. When the connected thin film transistor TFT1 is turned on, the current signal flows out through the thin film transistor TFT1 to the data line S and is transmitted to the driving circuit 200.

[0058] like Figure 2 and Figure 3As shown, when the row start signal VGH is input, due to the parasitic capacitance Cgs between the control end and the output end of the thin film transistor TFT1, the row start signal VGH will be transmitted to the data line S through the parasitic capacitance Cgs. When the photosensitive element 111 does not receive the laser pulse, a pulse level will still be generated on the data line S, resulting in the display panel 100 erroneously outputting a signal when no optical touch occurs on the display panel 100. When the drive circuit 200 reads the pulse level, the drive circuit 200 erroneously outputs a control signal, causing the display panel 100 to be erroneously triggered.

[0059] For this reason, in this embodiment, Figure 4 As shown, a driving circuit 200 of a display panel 100 is proposed, and the driving circuit 200 includes:

[0060] The row scanning circuit 210 is connected to the plurality of rows of scanning lines G, and is used to output row-on signals VGH to the plurality of rows of scanning lines G row by row, so as to turn on the thin film transistors TFT1 of each row row by row;

[0061] The sampling circuit 220 is connected to the plurality of column data lines S and is used to sample the current signal output by each column data line S during a preset period T2 within the output period T1 of each row start signal VGH, such as Figure 5 As shown, the first critical time point t3 of the preset period T2 lags behind the time point t1 of the rising edge of the row start signal VGH, the second critical time point t4 of the preset period T2 is ahead of the time point t2 of the falling edge of the row start signal VGH, and the first critical time point t3 is ahead of the second critical time point t4.

[0062] When the row scanning circuit 210 outputs the row start signal VGH row by row, the thin film transistors TFT1 of each row are turned on row by row. At this time, the pulse level generated by the rising edge of the row start signal VGH is transmitted to the data line S through the parasitic capacitor Cgs. At this time, the sampling circuit 220 does not collect signals. After the rising edge of the row start signal VGH ends, the sampling circuit 220 starts to collect signals at the first critical time point t3 of the preset period T2, and ends the signal collection at the second critical time point t4 of the preset period T2. During the preset period T2 and the photosensitive element 111 When receiving the laser pulse, the current signal generated by the photosensitive element 111 is output to the data line S through the thin film transistor TFT1. The sampling circuit 220 samples the current signal within the preset time period T2 without sampling the pulse level. The sampling circuit 220 can directly perform the touch control of the display panel 100 according to the sampled current signal, or output the corresponding sampling signal to the back-end control module, and the back-end module performs the touch control of the display panel 100, thereby preventing the pulse level from causing false triggering of the display panel 100 and improving the optical touch effect of the display panel 100.

[0063] By setting the sampling time point, the coupled pulse level is effectively avoided, the adverse effects are eliminated from the time dimension, and the problem of ghost points in touch caused by the coupling of the scan line G and the data line S in the display panel 100 is effectively solved, thereby improving the accuracy and stability of optical touch.

[0064] Among them, Figure 5 As shown, the setting method of the first critical time point t3 and the second critical time point t4 of the preset time period T2 can be determined according to the output time of the row start signal and the output time of the row close signal. When the row start signal VGH is output, the sampling circuit 220 starts sampling after delaying for a preset time, and ends sampling at a preset time before the row close signal VGL is output, thereby staggering the rising edge time and the falling edge time of the pulse level.

[0065] Among them, the row scanning circuit 210 can adopt a gate driving circuit, which can include multiple cascaded GOA units, each GOA unit is connected to a scanning line G, and the gate driving circuit outputs row scanning signals row by row according to the received clock signal, start signal, etc.

[0066] In order to realize the touch control operation of the display panel 100, further, as Figure 6 As shown, in an optional embodiment, the driving circuit 200 of the display panel 100 further includes:

[0067] The control processing circuit 230 is connected to the row scanning circuit 210 and the sampling circuit 220 respectively, and is used for:

[0068] The output row control signal controls the row scanning circuit 210 to output the row start signal VGH row by row;

[0069] The current sampling signal output by the sampling circuit 220 is acquired during a preset period T2 within the output period T1 of each row start signal VGH or after each frame ends, and the touch state of the display panel 100 is determined based on the current sampling signal.

[0070] In this embodiment, the control processing circuit 230 implements the function of the controller in the driving circuit 200 , and on the one hand triggers the output of the row control signal to the row scanning circuit 210 according to the received touch control command.

[0071] On the other hand, the photosensitive element 111 at the corresponding position of the display panel 100 receives the laser pulse. When the thin film transistor TFT1 connected to the photosensitive element 111 receives the row start signal VGH, the current signal is output to the data line S and the sampling circuit 220 through the thin film transistor TFT1. The sampling circuit 220 samples the current signal during the preset time period T2 within the output time period T1 of the row start signal VGH, and outputs the current sampling signal to the control processing circuit 230 during the preset time period T2. The control processing circuit 230 can choose to receive the current sampling signal within the preset time period T2 or receive each current sampling signal output by the sampling circuit 220 after a frame ends.

[0072] After receiving the current sampling signal, the control processing circuit 230 determines the touch position of the display panel 100 based on the current sampling signal, and controls the display panel 100 to switch to display corresponding image information or perform power on / off, screen pause, etc. based on the corresponding information of the touch position.

[0073] The control processing circuit 230 may adopt a structure of MCU, single chip microcomputer, etc.

[0074] In order to meet the signal types of MCU, single-chip microcomputer and other structures, in an optional embodiment, as Figure 7 As shown, the sampling circuit 220 includes:

[0075] A plurality of current-to-voltage circuits 221 are connected to the plurality of data lines S one by one, respectively, and the current-to-voltage circuits 221 are used to convert current signals into voltage signals;

[0076] The analog-to-digital converter 222 is connected to the plurality of current-to-voltage circuits 221 and is used to convert the voltage signal into a digital signal during a preset period T2 within the output period T1 of each row-enabling signal VGH.

[0077] In this embodiment, the photosensitive element 111 at the corresponding position of the display panel 100 receives a laser pulse. When the thin film transistor TFT1 connected to the photosensitive element 111 receives the row start signal VGH, the current signal is output to the data line S and the connected current-to-voltage circuit 221 through the thin film transistor TFT1. The current-to-voltage circuit 221 converts the output voltage signal, and the voltage signal is converted into a digital signal through the analog-to-digital converter 222. The digital signal is transmitted to the control processing circuit 230. The control processing circuit 230 determines the touch position of the display panel 100 according to the digital signal, and controls the display panel 100 to switch to display the corresponding image information or perform operations such as power on and off, pausing the screen, etc. based on the corresponding information of the touch position.

[0078] The current-to-voltage circuit 221 may be a capacitor, a resistor R1, etc. In an optional embodiment, Figure 8As shown, the current-to-voltage circuit 221 includes a resistor R1 , a first end of the resistor R1 is connected to the data line S to form a signal output end of the current-to-voltage circuit 221 , and a second end of the resistor R1 is grounded.

[0079] In this embodiment, the current signal is output to the resistor R1 , and a voltage signal that is positively correlated with the current signal is generated at the first end of the resistor R1 .

[0080] Among them, when the row start signal VGH is input, that is, when the rising edge is generated, the row start signal VGH is charged through the parasitic capacitor Cgs and the resistor R1, resulting in the output on the data line S being coupled by the row start signal VGH to generate a pulse level. The sampling circuit 220 effectively avoids sampling the coupled pulse level by setting the sampling time point, eliminates the adverse effects from the time dimension, and effectively solves the problem of ghost points in the touch caused by the coupling of the scan line G and the data line S in the display panel 100, thereby improving the accuracy and stability of the optical touch.

[0081] In order to further reduce the influence of the pulse level, in an optional embodiment, the time difference ΔT between the first critical time point t3 of the preset period T2 and the time point t1 of the rising edge of the row start signal VGH is greater than or equal to 5*R*C;

[0082] Wherein, R is the resistance value of the resistor R1 , and C is the parasitic capacitance Cgs between the gate and source of the thin film transistor TFT1 .

[0083] In the present embodiment, the generation of the pulse level is actually the charging process of the parasitic capacitor Cgs, and the duration of the pulse level is actually the charging time of the parasitic capacitor Cgs, and its specific duration is 5*R*C. For this reason, the sampling circuit 220 uses this time as the time difference △T, and the time difference between the first critical time point t3 of the preset time period T2 and the time point t1 of the rising edge of the row start signal VGH is at least △T, so that when collecting signals, the time difference is effectively avoided, and then the coupled pulse level is effectively avoided. The adverse effects are eliminated from the time dimension, and the problem of ghost points in the touch caused by the coupling of the scan line G and the data line S in the display panel 100 is effectively solved, thereby improving the accuracy and stability of the optical touch.

[0084] Furthermore, since the photosensitive units 110 arranged in the entire array have different positions, materials and structures, the parasitic capacitance Cgs generated are inconsistent, and therefore, the time difference ΔT cannot be uniformly set.

[0085] To this end, in another optional embodiment, the sampling circuit 220 samples the received electrical signal in real time, and detects and compares the waveform of the pulse level, determines the end time point of the time difference △T according to the comparison result, that is, determines the first critical time point t3 of the preset time period T2, and obtains the actual effective light touch data after the first critical time point t3 of the preset time period T2, thereby improving the sampling accuracy.

[0086] Correspondingly, in this embodiment, if Fig. 9 As shown, the sampling circuit 220 also includes a signal amplifying circuit 223, which is connected between the current-to-voltage circuit 221 and the analog-to-digital converter 222. The control processing circuit 230 includes a processor 231, a digital-to-analog converter 232 and a comparison circuit 233. The processor 231 is respectively connected to the output end of the analog-to-digital converter 222, the output end of the comparison circuit 233 and the input end of the digital-to-analog converter 232. The non-phase input end of the comparison circuit 233 is connected to the output end of the signal amplifying circuit 223, and the inverting input end of the comparison circuit 233 is connected to the output end of the digital-to-analog converter 232.

[0087] Among them, the signal amplification circuit 223 includes a second resistor R2, a third resistor R3 and an operational amplifier U1, the first end of the second resistor R2 is grounded, the second end of the second resistor R2, the first end of the third resistor R3 and the inverting input end of the operational amplifier U1 are connected, the non-inverting input end of the operational amplifier U1 constitutes the signal input end of the signal amplification circuit 223, the third resistor R3 is connected to the output end of the operational amplifier U1 to constitute the output end of the signal amplification circuit 223, and the comparison circuit 233 includes a comparator U2, the non-inverting input end, the inverting input end and the output end of the comparator U2 respectively constitute the non-inverting input end, the inverting input end and the output end of the comparison circuit 233.

[0088] The signal amplification circuit 223 is used to amplify the voltage signal output by the current-to-voltage circuit 221, and the amplified voltage signal is set to OUTn. The processor 231 samples the voltage of OUTn and controls the digital-to-analog converter 232 to output the reference voltage VREFn. The comparison circuit compares OUTn and VREFn, and outputs a comparison signal Ctrln to the processor 231. When OUTn is greater than VREFn, the comparison signal Ctrln is at a high level, and when OUTn is less than VREFn, the comparison signal Ctrln is at a low level. The processor 231 completes the collection of OUTn data by judging the level state of the comparison signal Ctrln.

[0089] The processor 231 is used to output a row control signal to control the row scanning circuit 210 to output a row start signal VGH row by row. Fig.10 and Fig.11As shown, initially, the reference voltage VREFn is set to an initial reference voltage, such as 3V.

[0090] When the processor 231 detects that the gate voltage Gn of the thin film transistor TFT1 changes from a low level to a high level, that is, when TFT1 receives the row start signal VGH, and OUTn is less than the initial reference voltage, and the comparison signal Ctrln is at a low level, the processor 231 controls the analog-to-digital converter 222 to sample OUTn multiple times, for example Fig.10 When the difference between adjacent data in the five collected data exceeds the preset difference, for example, 200mV, it indicates that the voltage of the currently collected data is too high, the analog-to-digital converter 222 samples the pulse level, and the initial reference voltage is set too high. At this time, the processor 231 discards the multiple collected data and reduces the reference voltage VREFn by the preset difference, for example, from 3V to 2.8V.

[0091] The processor 231 continues to judge Gn and the comparison signal Ctrln, and resamples OUTn multiple times, and judges whether the difference between adjacent data of the multiple collected data is the preset difference. When it does not exceed the preset difference, it indicates that the data voltage obtained by the current sampling is less than the voltage range of the pulse level, and the time point of each collected data is after the first critical time point t3 of the preset period T2, for example Fig.10 As shown, after multiple comparisons and judgments, and adjustment of the reference voltage VREFn, the sampled data voltage becomes smaller and smaller, and the difference between adjacent data of the last five samples is less than the preset difference, and the time range is after the first critical time point t3 of the preset period T2, indicating that the pulse level is not sampled this time, thereby staggering the rising edge moment and the falling edge moment of the pulse level, eliminating adverse effects from the time dimension and signal change, and effectively solving the problem of ghost points in touch caused by the coupling of the scan line G and the data line S in the display panel 100, thereby improving the accuracy and stability of optical touch.

[0092] Then, the processor 231 performs average processing on the data sampled multiple times to determine whether the average value exceeds the light touch threshold. If it exceeds, it is determined that there is currently a light touch operation, otherwise it is determined that there is no light touch operation. The touch position of the display panel 100 is determined based on the data, and the display panel 100 is controlled based on the corresponding information of the touch position to switch the display panel 100 to display the corresponding image information or perform power on and off, pause the screen, and other operations.

[0093] Embodiment 2

[0094] Based on the first embodiment, in an optional embodiment, as Fig.12 As shown, the current-to-voltage circuit 221 further includes a capacitor C1 , a first end of the capacitor C1 is connected to a first end of the resistor R1 , and a second end of the capacitor C1 is grounded.

[0095] In the present embodiment, at the moment when the level of the row start signal VGH is switched, the parasitic capacitor Cgs and the capacitor C1 form a series voltage divider circuit. When the capacitance of the capacitor C1 is much larger than the capacitance of the parasitic capacitor Cgs, the pulse level coupled on the data line S becomes very small. By introducing the capacitor C1, the coupling degree can be significantly reduced, and the influence of the pulse level can be reduced from the structural point of view. Combined with the sampling time, the problem of ghost points in touch caused by the coupling of the scan line G and the data line S in the display panel 100 can be further effectively solved, thereby improving the accuracy and stability of the optical touch.

[0096] Embodiment 3

[0097] Based on the first or second embodiment, Fig.13 As shown, in an optional embodiment, the driving circuit 200 further includes:

[0098] The plurality of voltage compensation circuits 240 are connected to the plurality of data lines S one by one, and output a negative voltage between the rising edge of the row start signal VGH and the initial time point of the preset period T2, and the negative voltage gradually decreases within ΔT.

[0099] In this embodiment, the sampling circuit 220 effectively avoids sampling the coupled pulse level by setting the sampling time point, thereby eliminating the adverse effects from the time dimension. The driving circuit 200 can also set a corresponding voltage compensation circuit 240 on each data line S to compensate for the pulse level within the time difference. The negative voltage and the pulse level offset each other, thereby eliminating the adverse effects of the pulse level on the signal, effectively solving the problem of ghost points in the touch caused by the coupling of the scan line G and the data line S in the display panel 100, and improving the accuracy and stability of the optical touch.

[0100] Among them, the voltage compensation circuit 240 can adopt circuit structures such as voltage source and LDO circuit. The size of the negative voltage can be set according to the size of the pulse level. At each time point within the time difference △T, the absolute value of the negative voltage is less than or equal to the size of the pulse level, thereby avoiding over-compensation and generating a new negative pulse level on the data line S, thereby improving the compensation effect.

[0101] Compared with the prior art, the embodiments of the present invention have the following beneficial effects: the driving circuit 200 of the display panel 100 includes a row scanning circuit 210 and a sampling circuit 220. The row scanning circuit 210 outputs a row start signal VGH to a plurality of row scanning lines G row by row to turn on the thin film transistors TFT1 of each row row by row. When the photosensitive element 111 receives a light signal and outputs a current signal, the current signal is output to the sampling circuit 220 via the corresponding thin film transistor TFT1 during the output period T1 of the row start signal VGH. To avoid mis-sampling, the sampling circuit 220 samples the current signal output by each column data line S during the preset period T2 within the output period T1 of the row start signal VGH, thereby effectively avoiding the pulse level generated by coupling and sampling a valid current signal, thereby accurately determining the touch point and improving the touch accuracy and reliability.

[0102] Embodiment 4

[0103] like Figure 1 As shown, the second aspect of an embodiment of the present invention proposes a display device 1, which includes a display panel 100 and a driving circuit 200 of the display panel 100. The specific structure of the driving circuit 200 of the display panel 100 refers to the above embodiment. Since the display device 1 adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be repeated here one by one.

[0104] Among them, the driving circuit 200 of the display panel 100 is connected to the display panel 100, and the driving circuit 200 is used to perform line scanning on the display panel 100. The display panel 100 converts the detected light signal into an electrical signal and outputs it to the driving circuit 200. The driving circuit 200 determines the touch position of the light signal based on the received electrical signal, thereby controlling the display panel 100 to display corresponding image information or switch display modes, switch display interfaces, turn on and off, and other operations.

[0105] like Figure 2As shown, the display panel 100 includes a photosensitive array, which includes photosensitive units 110 arranged in an array, multiple rows of scan lines G and multiple columns of data lines S. Multiple photosensitive units 110 in each row are connected to the same row of scan lines G, and multiple photosensitive units 110 in each column are connected to the same column of data lines S. The multiple rows of scan lines G input row start signals VGH row by row. When the row start signal VGH of each row is output to the multiple photosensitive units 110 in the same row, the photosensitive units 110 in each column of the row are turned on and enter a photosensitive mode. When one or more photosensitive units 110 in the row receive a laser pulse, the photosensitive unit 110 converts the laser pulse into an electrical signal and outputs it through the connected data line S. The driving circuit 200 determines the position of the optical touch according to the time of the output row start signal and the position of the data line S where the received electrical signal is located, thereby controlling the display panel 100 to display corresponding image information or switch display modes, switch display interfaces, turn on and off the machine, and other operations.

[0106] The photosensitive unit 110 may include a photosensitive element 111 and a corresponding switch tube, such as Figure 2 As shown, the photosensitive unit 110 includes a photosensitive element 111 and a thin film transistor TFT1, the photosensitive element 111 is connected to the input end of the thin film transistor TFT1, a row of scan lines G is connected to the control end of the thin film transistor TFT1 of a row of photosensitive units 110, a column of data lines S is connected to the output end of the thin film transistor TFT1 of a column of photosensitive units 110, and the photosensitive element 111 is used to receive light signals and convert output current signals.

[0107] The multiple scanning lines G input the row start signal VGH row by row. When the row start signal VGH of each row is output to the multiple photosensitive units 110 in the same row, the photosensitive units in each column of the row are turned on and enter the photosensitive mode, wherein the optical signal is mainly the laser pulse of the laser pen. When one or more photosensitive elements 111 in the row receive the laser pulse, the photosensitive element 111 performs photoelectric conversion. The photosensitive element 111 converts the laser pulse into a current signal. When the thin film transistor TFT1 connected to the photosensitive element 111 is turned on, the current signal flows out to the data line S through the thin film transistor TFT1 and is transmitted to the driving circuit 200. The driving circuit 200 determines the position of the optical touch according to the time of the output row start signal and the position of the data line where the received electrical signal is located, thereby controlling the display panel 100 to display the corresponding image information or switch the display mode, switch the display interface, turn on and off the machine, and other operations.

[0108] The driving circuit 200 effectively avoids sampling the coupled pulse level by setting the sampling time point, the voltage-dividing capacitor or the voltage compensation circuit 240, eliminates the adverse effects from the time dimension, structure and signal compensation method, and effectively solves the problem of ghost points in the touch caused by the coupling of the scan line G and the data line S in the display panel 100, thereby improving the accuracy and stability of the optical touch.

[0109] Among them, the photosensitive element 111 can adopt photosensitive structures such as photodiodes and photosensitive transistors TFT2. In an optional embodiment, the photosensitive element 111 is a photosensitive transistor TFT2, and the display panel 100 also includes a first power line 130 and a second power line 120. The first power line 130 is respectively connected to the first end of each photosensitive transistor TFT2, and the second power line 120 is respectively connected to the control end of each photosensitive transistor TFT2. The second end of the photosensitive transistor TFT2 constitutes the signal output end of the photosensitive element 111. The first power line 130 is used to input a first power signal VD, and the second power line 120 is used to input a second power signal VG.

[0110] The first power line 130 provides a first power signal VD to the first end of the photosensitive transistor TFT2 for providing a driving power supply. The second power line 120 provides a second power signal VG to the control end of the photosensitive transistor TFT2 for controlling the conduction of the photosensitive transistor TFT2. After receiving the laser pulse, the internal impedance of the photosensitive transistor TFT2 changes, and the ratio of the first power signal VD to the internal impedance changes, that is, the magnitude of its own current changes. The converted current signal is output to the connected thin film transistor TFT1. When the connected thin film transistor TFT1 is turned on, the current signal flows out through the thin film transistor TFT1 to the data line S and is transmitted to the driving circuit 200.

[0111] In an optional embodiment, the thin film transistor TFT1 and the photosensitive transistor TFT2 are N-channel thin film transistors TFT1.

[0112] Embodiment 5

[0113] A third aspect of an embodiment of the present invention proposes a driving method for a display panel 100, wherein the display panel 100 includes a photosensitive array, wherein the photosensitive array includes photosensitive units 110 arranged in an array, multiple rows of scan lines G, and multiple columns of data lines S, wherein the multiple photosensitive units 110 in each row are connected to the same row of scan lines G, and the multiple photosensitive units 110 in each column are connected to the same column of data lines S, and when the scan line G inputs a row start signal VGH, the row start signal VGH is output to the multiple photosensitive units 110 in the same row, and when each photosensitive unit 110 is turned on row by row, the multiple photosensitive units 110 in the same column output electrical signals through the same data line S.

[0114] The photosensitive unit 110 includes a photosensitive element 111 and a thin film transistor TFT1. The photosensitive element 111 is connected to the input end of the thin film transistor TFT1. A row of scan lines G is connected to the control end of the thin film transistor TFT1 of a row of photosensitive units 110. A column of data lines S is connected to the output end of the thin film transistor TFT1 of a column of photosensitive units 110. The photosensitive element 111 is used to receive light signals and convert output current signals.

[0115] Among them, the optical signal is mainly the laser pulse of the laser pen. When the photosensitive element 111 receives the laser pulse, the photosensitive element 111 performs photoelectric conversion and outputs a current signal. When the thin film transistor TFT1 connected to the photosensitive element 111 is turned on, the current signal flows out to the data line S through the thin film transistor TFT1.

[0116] like Fig.14 As shown, the driving method of the display panel 100 includes:

[0117] Step S10, outputting row-on signals VGH to the scan lines G row by row, so as to turn on the thin film transistors TFT1 of each row row by row;

[0118] Step S20, sampling the current signal output by each column data line S during a preset period T2 within the output period T1 of each row start signal VGH, such as Figure 5 As shown, the first critical time point t3 of the preset period T2 lags behind the time point t1 of the rising edge of the row start signal VGH, the second critical time point t4 of the preset period T2 is ahead of the time point t2 of the falling edge of the row start signal VGH, and the first critical time point t3 is ahead of the second critical time point t4.

[0119] When the row scanning circuit 210 outputs the row start signal VGH row by row, the thin film transistors TFT1 of each row are turned on row by row. At this time, the pulse level generated by the rising edge of the row start signal VGH is transmitted to the data line S through the parasitic capacitor Cgs. At this time, signal acquisition is not performed. After the rising edge of the row start signal VGH ends, signal acquisition starts at the first critical time point t3 of the preset period T2, and ends at the second critical time point t4 of the preset period T2. Within the preset period T2 and when the photosensitive element 111 receives the laser pulse, the current signal generated by the photosensitive element 111 is output to the data line S through the thin film transistor TFT1. The current signal is sampled within the preset period T2, and the pulse level is not sampled. The touch control operation of the display panel 100 can be directly performed according to the sampled current signal, or the corresponding sampling signal can be output to the back-end control module, and the back-end module performs the touch control operation of the display panel 100, thereby preventing the pulse level from causing false triggering of the display panel 100, and improving the optical touch effect of the display panel 100.

[0120] By setting the sampling time point, the coupled pulse level is effectively avoided, the adverse effects are eliminated from the time dimension, and the problem of ghost points in touch caused by the coupling of the scan line G and the data line S in the display panel 100 is effectively solved, thereby improving the accuracy and stability of optical touch.

[0121] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A driving circuit for a display panel, characterized in that: The display panel includes a photosensitive array, the photosensitive array includes photosensitive units arranged in an array, multiple rows of scanning lines and multiple columns of data lines, the photosensitive units include photosensitive elements and thin film transistors, the photosensitive elements are connected to input ends of the thin film transistors, a row of the scanning lines is connected to control ends of the thin film transistors of a row of the photosensitive units, a column of the data lines is connected to output ends of the thin film transistors of a column of the photosensitive units, and the photosensitive elements are used to receive light signals and convert output current signals; The driving circuit of the display panel comprises: A row scanning circuit connected to the plurality of rows of scanning lines, and used for outputting row-on signals to the plurality of rows of scanning lines row by row, so as to turn on the thin film transistors of each row row by row; A sampling circuit is connected to the multiple columns of data lines and is used to sample the current signals output by each column of data lines during a preset time period within the output time period of each row start signal, wherein a first critical time point of the preset time period lags behind a time point of a rising edge of the row start signal, a second critical time point of the preset time period precedes a time point of a falling edge of the row start signal, and the first critical time point precedes the second critical time point.

2. The driving circuit of the display panel according to claim 1, characterized in that: The driving circuit of the display panel further includes: The control processing circuit is connected to the row scanning circuit and the sampling circuit respectively, and is used for: Outputting a row control signal to control the row scanning circuit to output the row start signal row by row; A current sampling signal output by the sampling circuit is acquired during a preset period within each output period of the row start signal or after each frame ends, and a touch state of the display panel is determined based on the current sampling signal.

3. The driving circuit of the display panel according to claim 1, characterized in that: The sampling circuit comprises: A plurality of current-to-voltage circuits are connected to the plurality of data lines one by one, respectively, and the current-to-voltage circuits are used to convert the current signal into a voltage signal; The analog-to-digital converter is connected to the plurality of current-to-voltage circuits and is used to convert the voltage signal into a digital signal during a preset period within an output period of each row-on signal.

4. The driving circuit of the display panel according to claim 3, characterized in that: The current-to-voltage circuit comprises a resistor, a first end of the resistor is connected to the data line to form a signal output end of the current-to-voltage circuit, and a second end of the resistor is grounded.

5. The driving circuit of the display panel according to claim 4, characterized in that: A time difference ΔT between a first critical time point of the preset period and a time point of a rising edge of the row start signal, wherein ΔT is greater than or equal to 5*R*C; Wherein, R is the resistance value of the resistor, and C is the parasitic capacitance between the gate and source of the thin film transistor.

6. The driving circuit of the display panel according to claim 5, characterized in that: The current-to-voltage circuit further includes a capacitor, a first end of the capacitor is connected to the first end of the resistor, and a second end of the capacitor is grounded.

7. The driving circuit of the display panel according to claim 5 or 6, characterized in that: The driving circuit of the display panel further includes: A plurality of voltage compensation circuits are connected to the plurality of data lines one by one, respectively, and output a negative voltage between the rising edge of the row start signal and the initial time point of the preset period, and the negative voltage gradually decreases within the ΔT.

8. A display device, characterized in that: The invention comprises a display panel and a driving circuit for the display panel according to any one of claims 1 to 7, wherein the driving circuit for the display panel is connected to the display panel.

9. The display device according to claim 8, wherein: The photosensitive element is a photosensitive transistor, and the display panel also includes a first power line and a second power line, the first power line is respectively connected to the first end of each photosensitive transistor, the second power line is respectively connected to the control end of each photosensitive transistor, the second end of the photosensitive transistor constitutes the signal output end of the photosensitive element, the first power line is used to input a first power signal, and the second power line is used to input a second power signal.

10. A method for driving a display panel, characterized in that: The display panel includes a photosensitive array, the photosensitive array includes photosensitive units arranged in an array, multiple rows of scanning lines and multiple columns of data lines, the photosensitive units include photosensitive elements and thin film transistors, the photosensitive elements are connected to input ends of the thin film transistors, a row of the scanning lines is connected to control ends of the thin film transistors of a row of the photosensitive units, a column of the data lines is connected to output ends of the thin film transistors of a column of the photosensitive units, and the photosensitive elements are used to receive light signals and convert output current signals; The driving method of the display panel includes: Outputting row-on signals to the scan lines row by row to turn on the thin film transistors in each row row by row; The current signal output by each column data line is sampled during a preset time period within the output time period of each row start signal, the first critical time point of the preset time period lags behind the time point of the rising edge of the row start signal, the second critical time point of the preset time period is ahead of the time point of the falling edge of the row start signal, and the first critical time point is ahead of the second critical time point.

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