Driving circuit, driving method and display device of display panel

Abstract

The application provides a display panel driving circuit, a driving method and a display device. The display panel driving circuit comprises a row scanning circuit and a sampling circuit. The row scanning circuit outputs a row opening signal to a plurality of row scanning lines row by row, so as to open a thin film transistor in each row. When a photosensitive element receives a light signal and outputs a current signal, the current signal is output to the sampling circuit through the corresponding thin film transistor during the output period of the row opening signal. In order to avoid false sampling, the sampling circuit samples the current signal output by each column data line during a preset period in the output period of the row opening signal, so as to effectively avoid the pulse level generated by coupling and sample the effective current signal, thereby accurately determining the touch point and improving the touch accuracy and reliability.

Description

Technical Field

[0001] This invention belongs to the field of optical touch technology, and particularly relates to a driving circuit, driving method and display device for a display panel. Background Technology

[0002] In today's education field, engaging and vivid classroom experiments are becoming increasingly important to improve teaching effectiveness and student participation. Traditional experimental teaching methods are often subject to many limitations, while the emergence of simulation software has brought new possibilities to classroom experiments. Against this backdrop, the optical touch control solution has emerged. It achieves a touch effect simply by shining a laser pointer onto the display panel, providing a more flexible and convenient operating method for teaching, and has a wider range of applications.

[0003] However, a series of problems have arisen in the actual use of optical touch solutions. Among them, the touch position is inconsistent, and even ghost dots appear, seriously affecting the user experience. This has greatly hindered the promotion and application of optical touch solutions in the education field.

[0004] One reason is that the scan lines and data lines of the display panel can cause a parasitic capacitance Cgs to form between the control and output terminals of the display panel, such as... Figure 3 When the line scan signal changes from low to high or from high to low, the data line is coupled by the line scan signal to generate a pulse level. When data is acquired, the pulse level may be mistakenly acquired, causing areas that are not actually illuminated by the laser pointer to be identified as illuminated, resulting in abnormal touch points and false touches. Summary of the Invention

[0005] The purpose of this invention is to provide a driving circuit for a display panel, which aims to solve the problem of accidental touch control caused by pulse level in traditional display panels.

[0006] A first aspect of this invention provides a driving circuit for a display panel, the display panel including a photosensitive array, the photosensitive array including photosensitive units arranged in an array, multiple rows of scan lines and multiple columns of data lines, each photosensitive unit including a photosensitive element and a thin-film transistor, the photosensitive element being connected to the input terminal of the thin-film transistor, one row of scan lines being connected to the control terminal of the thin-film transistor of one row of photosensitive units, and one column of data lines being connected to the output terminal of the thin-film transistor of one column of photosensitive units, the photosensitive element being used to receive optical signals and convert them into output current signals;

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

[0008] A row scanning circuit, connected to multiple rows of the scan lines, is used to output row enable signals to the multiple rows of scan lines one by one, so as to enable the thin-film transistors of each row one by one;

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

[0012] The output row control signal controls the row scanning circuit to output the row enable signal line by line;

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

[0014] Optionally, the sampling circuit includes:

[0015] Multiple current-to-voltage circuits are connected to each of the multiple data lines, and the current-to-voltage circuits are used to convert the current signal into a voltage signal.

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

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

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

[0019] Where 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, the first end of which is connected to the first end of the resistor, and the second end of which is grounded.

[0021] Optionally, the driving circuit further includes:

[0022] Multiple voltage compensation circuits are connected to each of the multiple data lines, and output a negative voltage between the rising edge of the row enable signal and the initial time point of the preset time period. The negative voltage gradually decreases within the ΔT period.

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

[0024] Optionally, the photosensitive element is a photosensitive transistor, and the display panel further includes a first power line and a second power line. The first power line is connected to the first terminal of each of the photosensitive transistors, and the second power line is connected to the control terminal of each of the photosensitive transistors. The second terminal of the photosensitive transistor constitutes the signal output terminal 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 this invention provides a driving method for a display panel, the display panel including a photosensitive array, the photosensitive array including photosensitive units arranged in an array, multiple rows of scan lines and multiple columns of data lines, each photosensitive unit including a photosensitive element and a thin-film transistor, the photosensitive element being connected to the input terminal of the thin-film transistor, one row of scan lines being connected to the control terminal of the thin-film transistor of one row of photosensitive units, and one column of data lines being connected to the output terminal of the thin-film transistor of one column of photosensitive units, the photosensitive element being used to receive optical signals and convert them into output current signals;

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

[0027] Output row enable signals to each row of scan lines to enable the thin-film transistors in each row.

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

[0029] The beneficial effects of the present invention embodiments compared with the prior art are as follows: The driving circuit of the above-mentioned display panel includes a row scanning circuit and a sampling circuit. The row scanning circuit outputs a row enable signal to multiple row scanning lines one by one to enable the thin film transistors of each row one by one. When the photosensitive element receives the light signal and outputs a current signal, the current signal is output to the sampling circuit through the corresponding thin film transistor during the output period of the row enable signal. In order to avoid false sampling, the sampling circuit samples the current signal output by each column of data lines during a preset period within the output period of the row enable signal, thereby effectively avoiding the pulse level generated by coupling and sampling the effective current signal, thereby accurately determining the touch point and improving the touch accuracy and reliability. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 These are schematic diagrams of the display devices provided in Embodiments 1 and 4 of the present invention;

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

[0033] Figure 3 This is a waveform diagram of the row scanning signal and pulse level provided in Embodiment 1 of the present invention;

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

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

[0036] Figure 6 This is a schematic diagram of a second structure of the driving circuit provided in Embodiment 1 of the present invention;

[0037] Figure 7 This is a schematic diagram of a third structure of the driving circuit provided in Embodiment 1 of the present invention;

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

[0039] Figure 9 This is a circuit diagram of the sampling circuit and control processing circuit provided in Embodiment 2 of the present invention;

[0040] Figure 10 This is a schematic diagram of the signal waveform of the driving circuit provided in Embodiment 2 of the present invention;

[0041] Figure 11 This is a schematic diagram of the sampling process of the processor provided in Embodiment 2 of the present invention;

[0042] Figure 12 This is a schematic diagram of the driving circuit provided in Embodiment 2 of the present invention;

[0043] Figure 13 This is a schematic diagram of the driving circuit provided in Embodiment 3 of the present invention;

[0044] Figure 14 This is a flowchart illustrating the driving method provided in Embodiment 5 of the present invention;

[0045] The figures in the diagram are labeled as follows:

[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. Horizontal 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, Horizontal Layout Enable Signal; VGL, Horizontal Layout Disable Signal; T1, Output Period; T2, Preset Period; t1, Rising Edge Time Point; t2, Falling Edge Time Point; t3, First Critical Time Point; t4, Second Critical Time Point. Detailed Implementation

[0049] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0050] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0051] Example 1

[0052] A first aspect of this invention provides a driving circuit 200 for 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 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, power on / off, 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 receive row enable signals VGH one by one. When the row enable 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 that row are enabled and enter the photosensitive mode. When one or more photosensitive units 110 in that row receive a laser pulse, the photosensitive unit 110 converts the laser pulse into an electrical signal and outputs it through the connected data lines S. The driving circuit 200 determines the position of the light touch based on the time of the output row enable signal and the position of the received electrical signal on the data line S, thereby controlling the display panel 100 to display corresponding image information or switch display modes, switch display interfaces, power on / off, and other operations.

[0054] The photosensitive unit 110 may include a photosensitive element 111 and a corresponding switching transistor, such as... Figure 2 As shown, in an optional embodiment, the photosensitive unit 110 includes a photosensitive element 111 and a thin-film transistor TFT 1. The photosensitive element 111 is connected to the input terminal of the thin-film transistor TFT 1. A scan line G is connected to the control terminal of the thin-film transistor TFT 1 of a row of photosensitive units 110. A data line S is connected to the output terminal of the thin-film transistor TFT 1 of a row of photosensitive units 110. The photosensitive element 111 is used to receive optical signals and convert them into output current signals.

[0055] The multi-line scan line G receives the line enable signal VGH line by line. When the line enable signal VGH of each line is output to multiple photosensitive units 110 in the same line, the photosensitive units in each column of that line are turned on and enter the photosensitive mode. The light signal is mainly the laser pulse of the laser pointer. When one or more photosensitive elements 111 in that line receive the laser pulse, the photosensitive element 111 performs photoelectric conversion and 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 through the thin film transistor TFT1 to the data line S and is transmitted to the driving circuit 200. The driving circuit 200 determines the position of the light touch according to the time of the output line enable signal and the position of the received electrical signal on the data line, thereby controlling the display panel 100 to display the corresponding image information or switch the display mode, switch the display interface, power on / off, etc.

[0056] The photosensitive element 111 can be a photosensitive structure such as a photodiode or a photosensitive transistor TFT2. In an optional embodiment, the photosensitive element 111 is a photosensitive transistor TFT2. The display panel 100 also includes a first power line 130 and a second power line 120. The first power line 130 is connected to the first terminal of each photosensitive transistor TFT2, and the second power line 120 is connected to the control terminal of each photosensitive transistor TFT2. The second terminal of the photosensitive transistor TFT2 constitutes the signal output terminal 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 terminal of the photosensitive transistor TFT2 to provide driving power. The second power line 120 provides a second power signal VG to the control terminal of the photosensitive transistor TFT2 to control the photosensitive transistor TFT2 to turn on. After receiving a 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 current signal generated 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 horizontal unlock signal VGH is input, due to the parasitic capacitance Cgs between the control terminal and the output terminal of the thin-film transistor TFT1, the horizontal unlock signal VGH will be transmitted to the data line S through the parasitic capacitance Cgs. Even if the photosensitive element 111 does not receive the laser pulse, a pulse level will still be generated on the data line S. This causes the display panel 100 to output a signal erroneously when no optical touch occurs. When the driving circuit 200 reads this pulse level, the driving circuit 200 erroneously outputs a control signal, causing the display panel 100 to be erroneously triggered.

[0059] Therefore, in this embodiment, as Figure 4 As shown, a driving circuit 200 for a display panel 100 is proposed. The driving circuit 200 includes:

[0060] The row scanning circuit 210 is connected to the multi-row scanning line G and is used to output the row enable signal VGH to the multi-row scanning line G one row at a time to enable the thin film transistor TFT1 of each row one row at a time.

[0061] Sampling circuit 220, connected to multiple data lines S, is used to sample the current signal output from each data line S during a preset time period T2 within the output time period T1 of each row's enable signal VGH, such as... Figure 5 As shown, the first critical time point t3 of the preset time period T2 lags behind the rising edge of the line enable signal VGH at time point t1, the second critical time point t4 of the preset time period T2 precedes the falling edge of the line enable signal VGH at time point t2, and the first critical time point t3 precedes the second critical time point t4.

[0062] When the horizontal scanning circuit 210 outputs the horizontal enable signal VGH line by line, the thin-film transistors TFT1 of each line are turned on line by line. At this time, the pulse level generated by the rising edge of the horizontal enable signal VGH is transmitted to the data line S through the parasitic capacitance Cgs. At this time, the sampling circuit 220 does not perform signal acquisition. After the rising edge of the horizontal enable signal VGH ends, the sampling circuit 220 starts signal acquisition at the first critical time point t3 of the preset time period T2 and ends signal acquisition at the second critical time point t4 of the preset time period T2. During this preset time period T2, and the photosensitive element 111... When a laser pulse is received, the current signal generated by the photosensitive element 111 is output to the data line S via the thin-film transistor TFT1. The sampling circuit 220 samples the current signal within a preset time period T2 without sampling the pulse level. The sampling circuit 220 can directly perform touch operation on the display panel 100 based on the sampled current signal, or output the corresponding sampling signal to the back-end control module, which will then perform touch operation on the display panel 100. This prevents the display panel 100 from being falsely triggered by the pulse level and improves the optical touch effect of the display panel 100.

[0063] By setting the sampling time point, coupled pulse levels are effectively avoided, eliminating adverse effects from the time dimension. This effectively solves the problem of ghost dots appearing in the touch screen caused by the coupling between the scan line G and the data line S in the display panel 100, and improves the accuracy and stability of optical touch.

[0064] Among them, such as 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 horizontal start signal and the output time of the horizontal stop signal. When the horizontal start signal VGH is output, the sampling circuit 220 starts sampling after a preset delay and ends sampling after a preset time before the horizontal stop signal VGL is output, thereby staggering the rising edge time and falling edge time of the pulse level.

[0065] The row scanning circuit 210 may employ a gate driving circuit, which may include multiple cascaded GOA units. Each GOA unit is connected to a scan line G. The gate driving circuit outputs row scanning signals line by line according to the received clock signal, start signal, etc.

[0066] To enable touch operation of the display panel 100, further, such 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, connected to the row scanning circuit 210 and the sampling circuit 220 respectively, is used for:

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

[0069] During a preset time period T2 within the output period T1 of each line enable signal VGH, or after the end of each frame, the current sampling signal output by the sampling circuit 220 is acquired, 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 performs the function of the controller in the drive circuit 200. On the one hand, it triggers the output of the row control signal to the row scanning circuit 210 according to the received touch 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 photosensitive element 111 receives the horizontal enable signal VGH in the connected thin film transistor TFT1, 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 a preset time period T2 within the output time period T1 of the horizontal enable 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 during 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 the corresponding image information or perform power on / off, screen pause, and other operations based on the information corresponding to the touch position.

[0073] The control processing circuit 230 can adopt a structure such as MCU or single-chip microcomputer.

[0074] To accommodate the signal types of MCUs, microcontrollers, and other similar architectures, in one optional embodiment, such as... Figure 7 As shown, the sampling circuit 220 includes:

[0075] Multiple current-to-voltage circuits 221 are connected to multiple data lines S one by one. The current-to-voltage circuits 221 are used to convert current signals into voltage signals.

[0076] The analog-to-digital converter 222, connected to multiple current-to-voltage circuits 221, is used to convert voltage signals into digital signals during a preset time period T2 within the output time period T1 of each row of the turn 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 photosensitive element 111 receives the horizontal enable signal VGH from the connected thin-film transistor TFT1, the current signal is output through the thin-film transistor TFT1 to the data line S and a connected current-to-voltage circuit 221. The current-to-voltage circuit 221 converts the output voltage signal, which is then converted into a digital signal by 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 based on the digital signal and controls the display panel 100 to switch to display the corresponding image information or perform operations such as power on / off or screen pause based on the information corresponding to the touch position.

[0078] The current-to-voltage circuit 221 can employ a capacitor, resistor R1, or similar structure. In one optional embodiment, for example... Figure 8As shown, the current-to-voltage circuit 221 includes a resistor R1. The first end of the resistor R1 is connected to the data line S to form the signal output terminal of the current-to-voltage circuit 221, and the second end of the resistor R1 is grounded.

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

[0080] When the horizontal enable signal VGH is input, i.e. when the rising edge is generated, the horizontal enable signal VGH is charged through the parasitic capacitance Cgs and the resistor R1, which causes the output on the data line S to be coupled by the horizontal enable signal VGH to generate a pulse level. The sampling circuit 220 effectively avoids sampling the coupled pulse level by setting the sampling time point, thus eliminating the adverse effects from the time dimension. This effectively solves the problem of ghost dots in the touch caused by the coupling between the scan line G and the data line S in the display panel 100, and improves the accuracy and stability of optical touch.

[0081] To further reduce the impact of pulse levels, in an optional embodiment, the time difference ΔT between the first critical time point t3 of the preset time period T2 and the time point t1 of the rising edge of the line enable signal VGH is greater than or equal to 5*R*C.

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

[0083] In this embodiment, the generation of the pulse level is actually the charging process of the parasitic capacitance Cgs, and the duration of the pulse level is actually the charging time of the parasitic capacitance Cgs, specifically 5*R*C. Therefore, the sampling circuit 220 uses this time as the time difference ΔT. The time difference between the first critical time point t3 of the preset time period T2 and the rising edge time point t1 of the horizontal opening signal VGH is at least ΔT. Thus, when acquiring the signal, this time difference is effectively avoided, thereby effectively avoiding the acquisition of coupled pulse levels. This eliminates 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, improving the accuracy and stability of optical touch.

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

[0085] Therefore, in another optional embodiment, the sampling circuit 220 samples the received electrical signal in real time, detects and compares the waveform of the pulse level, determines the end time point of the time difference ΔT based on 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, as Figure 9 As shown, the sampling circuit 220 also includes a signal amplification 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 comparator circuit 233. The processor 231 is connected to the output terminal of the analog-to-digital converter 222, the output terminal of the comparator circuit 233, and the input terminal of the digital-to-analog converter 232, respectively. The non-inverting input terminal of the comparator circuit 233 is connected to the output terminal of the signal amplification circuit 223, and the inverting input terminal of the comparator circuit 233 is connected to the output terminal of the digital-to-analog converter 232.

[0087] 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 of the operational amplifier U1 are connected. The non-inverting input of the operational amplifier U1 constitutes the signal input of the signal amplification circuit 223. The third resistor R3 is connected to the output of the operational amplifier U1 to constitute the output of the signal amplification circuit 223. The comparator circuit 233 includes a comparator U2. The non-inverting input, inverting input, and output of the comparator U2 constitute the non-inverting input, inverting input, and output of the comparator circuit 233, respectively.

[0088] The signal amplification circuit 223 amplifies the voltage signal output by the current-to-voltage circuit 221. The amplified voltage signal is set as OUTn. The processor 231 samples the voltage of OUTn and controls the digital-to-analog converter 232 to output a reference voltage VREFn. The comparator 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 high, and when OUTn is less than VREFn, the comparison signal Ctrln is low. The processor 231 completes the acquisition of OUTn data by judging the level state of the comparison signal Ctrln.

[0089] Among them, processor 231 is used to output row control signals to control row scanning circuit 210 to output row enable signals VGH line by line, such as Figure 10 and Figure 11As shown, initially, the reference voltage VREFn is set to the initial reference voltage, for example, 3V.

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

[0091] Processor 231 continues to judge Gn and the comparison signal Ctrln, and resamples OUTn multiple times. It then checks whether the difference between adjacent data points in the multiple samplings exceeds a preset difference. If the difference does not exceed the preset difference, it indicates that the voltage of the currently sampled data is less than the voltage range of the pulse level, and the time point of each sampled data point is after the first critical time point t3 of the preset time period T2. For example... Figure 10 As shown, after multiple comparisons and adjustments to the reference voltage VREFn, the sampled data voltage becomes smaller and smaller. The difference between adjacent data in 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 time period T2. This indicates that no pulse level was sampled this time, thus avoiding the rising and falling edges of the pulse level. This eliminates the adverse effects from the perspective of time and signal changes, effectively solving the problem of ghost points caused by the coupling between the scan line G and the data line S in the display panel 100, and improving the accuracy and stability of optical touch.

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

[0093] Example 2

[0094] Based on Embodiment 1, in an optional embodiment, such as Figure 12 As shown, the current-to-voltage circuit 221 also includes a capacitor C1. The first end of the capacitor C1 is connected to the first end of the resistor R1, and the second end of the capacitor C1 is grounded.

[0095] In this embodiment, at the moment when the level of the row enable signal VGH switches, the parasitic capacitance 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 capacitance Cgs, the coupled pulse level 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 structurally. Combined with the sampling time, the problem of ghost points caused by the coupling between the scan line G and the data line S in the display panel 100 can be further effectively solved, improving the accuracy and stability of optical touch.

[0096] Example 3

[0097] Based on Embodiment 1 or Embodiment 2, such as Figure 13 As shown, in an optional embodiment, the driving circuit 200 further includes:

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

[0099] In this embodiment, the sampling circuit 220 effectively avoids sampling coupled pulse levels by setting the sampling time point, thus eliminating 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 pulse levels within the time difference. The negative voltage cancels out the pulse level, thereby eliminating the adverse effects of pulse levels in terms of signal. This effectively solves the problem of ghost points in touch caused by the coupling between the scan line G and the data line S in the display panel 100, and improves the accuracy and stability of optical touch.

[0100] The voltage compensation circuit 240 can adopt circuit structures such as voltage source and LDO circuit. The magnitude of the negative voltage can be set according to the magnitude of the pulse level. At each time point within the time difference ΔT, the absolute value of the negative voltage is less than or equal to the magnitude of the pulse level, thereby avoiding overcompensation that would cause a new negative pulse level to be generated on the data line S, and improving the compensation effect.

[0101] The beneficial effects of the present invention embodiment compared with the prior art are as follows: The driving circuit 200 of the above-mentioned display panel 100 includes a row scanning circuit 210 and a sampling circuit 220. The row scanning circuit 210 outputs a row enable signal VGH to multiple row scanning lines G one by one to enable the thin film transistor TFT1 of each row. When the photosensitive element 111 receives the light signal and outputs the current signal, the current signal is output to the sampling circuit 220 through the corresponding thin film transistor TFT1 during the output period T1 of the row enable signal VGH. In order to avoid false sampling, the sampling circuit 220 samples the current signal output by each column data line S during a preset period T2 within the output period T1 of the row enable signal VGH, thereby effectively avoiding the pulse level generated by coupling and sampling the effective current signal, thereby accurately determining the touch point and improving the touch accuracy and reliability.

[0102] Example 4

[0103] like Figure 1 As shown, a second aspect of the present invention provides a display device 1, which includes a display panel 100 and a driving circuit 200 for the display panel 100. The specific structure of the driving circuit 200 for the display panel 100 is as described in the above embodiments. Since the display device 1 adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0104] The driving circuit 200 of the display panel 100 is connected to the display panel 100. 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, power on / 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 receive row enable signals VGH one by one. When the row enable 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 that row are enabled and enter the photosensitive mode. When one or more photosensitive units 110 in that row receive a laser pulse, the photosensitive unit 110 converts the laser pulse into an electrical signal and outputs it through the connected data lines S. The driving circuit 200 determines the position of the light touch based on the time of the output row enable signal and the position of the received electrical signal on the data line S, thereby controlling the display panel 100 to display corresponding image information or switch display modes, switch display interfaces, power on / off, and other operations.

[0106] The photosensitive unit 110 may include a photosensitive element 111 and a corresponding switching transistor, such as... Figure 2 As shown, the photosensitive unit 110 includes a photosensitive element 111 and a thin-film transistor TFT 1. The photosensitive element 111 is connected to the input terminal of the thin-film transistor TFT 1. A scan line G is connected to the control terminal of the thin-film transistor TFT 1 of the photosensitive unit 110 in one row. A data line S is connected to the output terminal of the thin-film transistor TFT 1 of the photosensitive unit 110 in one row. The photosensitive element 111 is used to receive optical signals and convert them into output current signals.

[0107] The multi-line scan line G receives the line enable signal VGH line by line. When the line enable signal VGH of each line is output to multiple photosensitive units 110 in the same line, the photosensitive units in each column of that line are turned on and enter the photosensitive mode. The light signal is mainly the laser pulse of the laser pointer. When one or more photosensitive elements 111 in that line receive the laser pulse, the photosensitive element 111 performs photoelectric conversion and 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 through the thin film transistor TFT1 to the data line S and is transmitted to the driving circuit 200. The driving circuit 200 determines the position of the light touch according to the time of the output line enable signal and the position of the received electrical signal on the data line, thereby controlling the display panel 100 to display the corresponding image information or switch the display mode, switch the display interface, power on / off, etc.

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

[0109] The photosensitive element 111 can be a photosensitive structure such as a photodiode or a photosensitive transistor TFT2. In an optional embodiment, the photosensitive element 111 is a photosensitive transistor TFT2. The display panel 100 also includes a first power line 130 and a second power line 120. The first power line 130 is connected to the first terminal of each photosensitive transistor TFT2, and the second power line 120 is connected to the control terminal of each photosensitive transistor TFT2. The second terminal of the photosensitive transistor TFT2 constitutes the signal output terminal 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 terminal of the photosensitive transistor TFT2 to provide driving power. The second power line 120 provides a second power signal VG to the control terminal of the photosensitive transistor TFT2 to control the photosensitive transistor TFT2 to turn on. After receiving a 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 current signal generated 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 alternative embodiment, the thin-film transistor TFT1 and the photosensitive transistor TFT2 are N-channel thin-film transistor TFT1.

[0112] Example 5

[0113] A third aspect of the present invention provides a driving method for a display panel 100. 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. When a row enable signal VGH is input to the scan line G, the row enable signal VGH is output to the multiple photosensitive units 110 in the same row. When each photosensitive unit 110 is enabled 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 TFT 1. The photosensitive element 111 is connected to the input terminal of the thin-film transistor TFT 1. A scan line G is connected to the control terminal of the thin-film transistor TFT 1 of the photosensitive unit 110 in one row. A data line S is connected to the output terminal of the thin-film transistor TFT 1 of the photosensitive unit 110 in one row. The photosensitive element 111 is used to receive optical signals and convert them into output current signals.

[0115] Among them, the optical signal is mainly the laser pulse of the laser pointer. 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 Figure 14 As shown, the driving method for the display panel 100 includes:

[0117] Step S10: Output the row enable signal VGH to each row scan line G to enable the thin film transistor TFT1 of each row one by one;

[0118] Step S20: During the preset time period T2 within the output time period T1 of the turn signal VGH in each row, sample the current signal output from each column data line S, such as... Figure 5 As shown, the first critical time point t3 of the preset time period T2 lags behind the rising edge of the line enable signal VGH at time point t1, the second critical time point t4 of the preset time period T2 precedes the falling edge of the line enable signal VGH at time point t2, and the first critical time point t3 precedes the second critical time point t4.

[0119] When the horizontal scanning circuit 210 outputs the horizontal activation signal VGH line by line, the thin-film transistors TFT1 of each line are turned on line by line. At this time, the pulse level generated by the rising edge of the horizontal activation signal VGH is transmitted to the data line S through the parasitic capacitance Cgs. At this time, no signal acquisition is performed. After the rising edge of the horizontal activation signal VGH ends, signal acquisition begins at the first critical time point t3 of the preset time period T2 and ends at the second critical time point t4 of the preset time period T2. During the preset time period T2, 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 during the preset time period T2, and no pulse level is sampled. The touch operation of the display panel 100 can be performed directly based on the sampled current signal, or the corresponding sampling signal can be output to the back-end control module, and the back-end module can perform the touch operation of the display panel 100. This prevents the display panel 100 from being falsely triggered by the pulse level and improves the optical touch effect of the display panel 100.

[0120] By setting the sampling time point, coupled pulse levels are effectively avoided, eliminating adverse effects from the time dimension. This effectively solves the problem of ghost dots appearing in the touch screen caused by the coupling between the scan line G and the data line S in the display panel 100, and improves the accuracy and stability of optical touch.

[0121] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within 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, which includes photosensitive units arranged in an array, multiple rows of scan lines, and multiple columns of data lines. Each photosensitive unit includes a photosensitive element and a thin-film transistor. The photosensitive element is connected to the input terminal of the thin-film transistor. Each row of scan lines is connected to the control terminal of the thin-film transistor of the photosensitive unit in that row. Each column of data lines is connected to the output terminal of the thin-film transistor of the photosensitive unit in that column. The photosensitive element is used to receive optical signals and convert them into output current signals. The driving circuit of the display panel includes: A row scanning circuit, connected to multiple rows of the scan lines, is used to output row enable signals to the multiple rows of scan lines one by one, so as to enable the thin-film transistors of each row one by one; A sampling circuit, connected to multiple columns of data lines, is used to sample the current signal output by each column of data lines during a preset time period within the output time period of each row enable signal. The first critical time point of the preset time period lags behind the rising edge of the row enable signal, and the second critical time point of the preset time period precedes the falling edge of the row enable signal. The first critical time point precedes the second critical time point. The sampling circuit includes: Multiple current-to-voltage circuits are connected to each of the multiple data lines, and the current-to-voltage circuits are used to convert the current signal into a voltage signal. An analog-to-digital converter, connected to a plurality of the current-to-voltage circuits, is used to convert the voltage signal into a digital signal during a preset time period within the output period of each of the row-on signals; The current-to-voltage circuit includes a resistor. The first end of the resistor is connected to the data line to form the signal output terminal of the current-to-voltage circuit, and the second end of the resistor is grounded. The time difference ΔT between the first critical time point of the preset time period and the rising edge of the line start signal is greater than or equal to 5*R*C. Where R is the resistance value of the resistor, and C is the parasitic capacitance between the gate and source of the thin-film transistor.

2. The driving circuit for the display panel as described in claim 1, characterized in that, The driving circuit of the display panel also includes: The control processing circuit, connected to the row scanning circuit and the sampling circuit respectively, is used for: The output row control signal controls the row scanning circuit to output the row enable signal line by line; The current sampling signal output by the sampling circuit is acquired during a preset time period within the output period of each row enable signal or after the end of each frame, and the touch state of the display panel is determined based on the current sampling signal.

3. The driving circuit for the display panel as described in claim 1, characterized in that, The current-to-voltage circuit also includes a capacitor, the first end of which is connected to the first end of the resistor, and the second end of the capacitor is grounded.

4. The driving circuit for the display panel as described in claim 3, characterized in that, The driving circuit of the display panel also includes: Multiple voltage compensation circuits are connected to each of the multiple data lines, and output a negative voltage between the rising edge of the row enable signal and the initial time point of the preset time period. The negative voltage gradually decreases within the ΔT period.

5. A display device, characterized in that, It includes a display panel and a driving circuit for the display panel as described in any one of claims 1 to 4, wherein the driving circuit for the display panel is connected to the display panel.

6. The display device as claimed in claim 5, characterized in that, The photosensitive element is a photosensitive transistor. The display panel also includes a first power line and a second power line. The first power line is connected to the first terminal of each photosensitive transistor, and the second power line is connected to the control terminal of each photosensitive transistor. The second terminal of the photosensitive transistor constitutes the signal output terminal 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.

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