Liquid crystal display circuit, method and apparatus

Abstract

The application relates to the fingerprint detection field and provides a liquid crystal display circuit, method and device.The circuit comprises a sub-pixel circuit and a current detection circuit, wherein the liquid crystal display circuit comprises the sub-pixel circuit, a voltage detection circuit and the current detection circuit; the sub-pixel circuit comprises a sensing electrode plate, liquid crystal, a first controllable switch, a second controllable switch and a third controllable switch; the second liquid crystal electrode of the liquid crystal is used for receiving a second control signal; the second control signal is used for providing voltage change information for the voltage detection circuit and providing current change information for the current detection circuit; the voltage change caused by the change of a sensing capacitor is detected through the voltage detection circuit, and the current change caused by the sensing capacitor is detected through the current detection circuit, so that accurate and effective fingerprint detection can be realized on the liquid crystal display screen, the convenience of use of a user is improved, and the sensing electrode and the first liquid crystal electrode utilize the same electrode plate, thereby effectively reducing the product cost.

Description

Technical Field

[0001] This application relates to the field of fingerprint detection, and more particularly to liquid crystal display circuits, methods and devices. Background Technology

[0002] Fingerprint unlocking is a technology that uses fingerprints, a biometric feature of the human body, for identification. Because fingerprint unlocking eliminates the need to remember a password and the process is less prone to data breaches, it is commonly used in devices such as smartphones and door locks.

[0003] With the widespread use of full-screen smartphones, under-display fingerprint designs can effectively improve user convenience. However, current under-display fingerprint technology is typically used in OLED (Organic Electroluminescence Display) panels. For LCD (Liquid Crystal Display) screens, which have lower production costs and better display effects, the fingerprint sensor in smartphones and other devices is usually located on the back or side of the device. This is not conducive to improving user convenience, reducing product costs, or improving detection accuracy. Summary of the Invention

[0004] In view of this, embodiments of this application provide a liquid crystal display circuit, method, and apparatus to solve the problem that the use of fingerprint collection devices in LCD devices in the prior art is not conducive to improving user convenience and reducing product costs.

[0005] A first aspect of this application provides a liquid crystal display circuit, the liquid crystal display circuit including a sub-pixel circuit, a voltage detection circuit, and a current detection circuit, the sub-pixel circuit including a sensing electrode plate, liquid crystal, a first controllable switch, a second controllable switch, and a third controllable switch, wherein:

[0006] The sensing electrode plate is connected to the first switch pin of the first controllable switch, the first switch pin of the second controllable switch, and the first switch pin of the third controllable switch, respectively. The sensing electrode plate and the first liquid crystal electrode of the liquid crystal share the same electrode plate.

[0007] The second switch pin of the first controllable switch is used to connect to a preset voltage source, and the first controllable switch is used to reset the first liquid crystal electrode of the liquid crystal to the first preset voltage according to the first control signal;

[0008] The second liquid crystal electrode of the liquid crystal is used to receive a second control signal, which is used to provide voltage change information to the voltage detection circuit and current change information to the current detection circuit.

[0009] The second switch pin of the second controllable switch is connected to the voltage detection circuit. The second controllable switch is used to transmit the change information of the sensing capacitance of the sensing electrode plate to the voltage detection circuit for fingerprint detection.

[0010] The second switch pin of the third controllable switch is used to receive a reset signal to reset the first liquid crystal electrode of the liquid crystal to a second preset voltage.

[0011] In conjunction with the first aspect, in a first possible implementation of the first aspect, the current detection circuit includes a driving circuit and a detection circuit. The driving circuit is used to convert display data into a driving voltage and drive the first liquid crystal electrode to a predetermined voltage. The detection circuit is used to detect the amount of charge driven to the predetermined voltage by the driving circuit and perform fingerprint detection based on the amount of charge.

[0012] In conjunction with the first possible implementation of the first aspect, in the second possible implementation of the first aspect, the driving circuit includes a digital-to-analog converter circuit and a first integrated operational amplifier. The digital-to-analog converter circuit is used to convert display data into a display voltage, and the first integrated operational amplifier is used to amplify the display voltage and output a driving voltage.

[0013] In conjunction with the first possible implementation of the first aspect, in the third possible implementation of the first aspect, the detection circuit includes a second integrated operational amplifier, a feedback capacitor, a fourth controllable switch, and an analog-to-digital converter circuit. The feedback capacitor and the fourth controllable switch are connected in parallel. The first end of the feedback capacitor is connected to the negative input terminal of the second integrated operational amplifier, and the second end of the feedback capacitor is connected to the output terminal of the second integrated operational amplifier. The output terminal of the second integrated operational amplifier is connected to the analog-to-digital converter circuit. The control pin of the fourth controllable switch is used to control the discharge of the feedback capacitor according to a reset signal.

[0014] In conjunction with the first aspect, in the fourth possible implementation of the first aspect, the control terminal of the first controllable switch is used to receive the (n-1)th row scan signal in the progressive scan signal, the control terminal of the second controllable switch is used to receive the nth row scan signal in the progressive scan signal, and the reset signal of the third controllable switch is the (n+1)th row scan signal, where n is a natural number greater than 0.

[0015] In conjunction with the first aspect, in a fifth possible implementation of the first aspect, the current detection circuit includes a fifth controllable switch, the control pin of the fifth controllable switch being connected to the second liquid crystal electrode of the liquid crystal, the first switch pin of the fifth controllable switch being connected to ground, and the second switch pin of the fifth controllable switch being used to determine a corresponding current signal based on the voltage of the second liquid crystal electrode of the liquid crystal.

[0016] In conjunction with the first aspect, in a sixth possible implementation of the first aspect, the current detection circuit includes a fifth controllable switch and a sixth controllable switch. The control pin of the fifth controllable switch is connected to the second liquid crystal electrode of the liquid crystal, the first switch pin of the fifth controllable switch is connected to ground, the second switch pin of the fifth controllable switch is used to determine a corresponding current signal based on the voltage of the second liquid crystal electrode of the liquid crystal through the sixth controllable switch, and the control pin of the sixth controllable switch is used to receive a second control signal.

[0017] In a second aspect, embodiments of this application provide a liquid crystal display method, which is based on any one of the liquid crystal display circuits in the first aspect to the sixth possible implementation of the first aspect, and the method includes:

[0018] The pixel sub-circuit is reset by controlling the first control signal, thereby resetting the first liquid crystal electrode to a preset voltage, and the current detection circuit is also reset.

[0019] The second control signal controls the current detection circuit to drive the first liquid crystal electrode to a predetermined voltage, so that the current detection circuit performs fingerprint detection based on the amount of charge required to drive the predetermined voltage and the voltage change of the first liquid crystal electrode of the liquid crystal determined by the voltage detection circuit.

[0020] In conjunction with the second aspect, in a first possible implementation of the second aspect, the method further includes:

[0021] The third controllable switch is closed by controlling the third control signal, so that the first liquid crystal electrode of the liquid crystal is reset to the second preset voltage.

[0022] A third aspect of this application provides a liquid crystal display device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the method as described in any of the first aspects.

[0023] A fourth aspect of this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the method as described in any of the first aspects.

[0024] The beneficial effects of this application embodiment compared with the prior art are as follows: By setting a sub-pixel circuit, a voltage detection circuit, and a current detection circuit in the fingerprint detection circuit, the first controllable switch is closed by a first control signal to reset the first liquid crystal electrode of the liquid crystal to a first preset voltage. Then, the second controllable switch is closed by a second control signal to increase the voltage of the second liquid crystal electrode of the liquid crystal. This allows the current detection circuit and the voltage detection circuit to detect the change in the sensing capacitance of the sensing electrode, thereby performing fingerprint detection based on the voltage detection circuit and the current detection circuit. This is beneficial to improving the fingerprint detection accuracy of the liquid crystal display screen. Furthermore, the sensing electrode plate and the first liquid crystal electrode of the liquid crystal use the same electrode plate, which is beneficial to reducing product costs. Attached Figure Description

[0025] 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.

[0026] Figure 1 This is a schematic diagram of the circuit structure of a liquid crystal display circuit provided in an embodiment of this application;

[0027] Figure 2 This is a schematic diagram of the circuit structure of another liquid crystal display circuit provided in an embodiment of this application;

[0028] Figure 3 This is a control timing diagram of a liquid crystal display circuit provided in an embodiment of this application;

[0029] Figure 4 This is a schematic diagram of control signals for a liquid crystal display circuit provided in an embodiment of this application;

[0030] Figure 5 This is a schematic diagram of control signals for another liquid crystal display circuit provided in an embodiment of this application;

[0031] Figure 6 A schematic diagram illustrating the implementation process of a liquid crystal display method provided in this application embodiment;

[0032] Figure 7 This is a schematic diagram of a liquid crystal display device provided in an embodiment of this application;

[0033] Figure 8 This is a schematic diagram of a liquid crystal display device provided in an embodiment of this application. Detailed Implementation

[0034] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0035] To illustrate the technical solution described in this application, specific embodiments are provided below.

[0036] Fingerprint unlocking is a technology that uses the biometric features of a person's fingerprints for identification. Because fingerprint unlocking eliminates the need to remember a password, makes it less likely for keys to be lost, and minimizes the risk of information leakage during the unlocking process, it is commonly used in devices such as smartphones and door locks.

[0037] With the widespread use of full-screen smartphones, under-display fingerprint design allows the fingerprint sensor to be directly integrated into the screen, eliminating the need for other locations on the phone. This improves both design convenience and user experience. However, current under-display fingerprint technology is typically used in OLED (Organic Electroluminescence Display) panels. For LCD (Liquid Crystal Display) screens, which offer lower production costs and better display quality, the fingerprint sensor in smartphones and other devices is usually located on the back or side of the device. This location is less convenient for users, hinders detection accuracy, and reduces product costs.

[0038] To address the aforementioned problems, embodiments of this application propose a liquid crystal display circuit, method, and apparatus. A self-capacitance sensing circuit is fabricated using thin-film transistor technology, integrating the liquid crystal display and fingerprint sensing device while driving the liquid crystal display. Figure 1 The diagram shown is a schematic representation of a liquid crystal display circuit according to an embodiment of this application. The circuit includes a sub-pixel circuit 1, a current detection circuit 2, and a voltage detection circuit 3. The sub-pixel circuit 1 includes a sensing electrode plate SC, a liquid crystal LC, a first controllable switch K1, a second controllable switch K2, and a third controllable switch K3, wherein:

[0039] The sensing electrode plate SC is connected to the first switch pin of the first controllable switch K1, the first switch pin of the second controllable switch K2, and the first switch pin of the third controllable switch K3, respectively. The sensing electrode plate SC and the first liquid crystal electrode of the liquid crystal LC share the same electrode plate.

[0040] The second switch pin of the first controllable switch K1 is used to connect to a preset voltage source, and the first controllable switch K1 is used to reset the first liquid crystal electrode of the liquid crystal LC to the first preset voltage according to the first control signal.

[0041] The second liquid crystal electrode of the liquid crystal LC is used to receive a second control signal, which is used to provide voltage change information to the voltage detection circuit 3 and current change information to the current detection circuit 2.

[0042] The second switch pin of the second controllable switch K2 is connected to the current detection circuit 2. The second controllable switch K2 is used to transmit the voltage change information of the first liquid crystal electrode of the liquid crystal LC to the voltage detection circuit 3 for fingerprint detection.

[0043] The second switch pin of the third controllable switch K3 is used to receive a reset signal to reset the first liquid crystal electrode of the liquid crystal LC to the second preset voltage.

[0044] The voltage detection circuit includes a fifth controllable switch K5. The control pin of the fifth controllable switch K5 is connected to the second liquid crystal electrode of the liquid crystal LC. The first switch pin of the fifth controllable switch K5 is connected to ground. The second switch pin of the fifth controllable switch K5 is used to determine the corresponding current signal based on the voltage of the second liquid crystal electrode of the liquid crystal LC.

[0045] Among them, the first controllable switch K1, the second controllable switch K2, the third controllable switch K3, the fifth controllable switch K5, and the sixth controllable switch K6 mentioned later can be thin-film transistors.

[0046] A subpixel refers to a separate red, green, or blue display area when a display device uses RGB three primary colors or RGBW four primary colors to form a pixel.

[0047] The sensing electrode plate SC is used to form a sensing capacitance with the finger. When a finger touches the screen, the finger and the sensing electrode plate SC form a sensing capacitance, and due to the presence of the fingerprint, different sensing capacitance values ​​are generated.

[0048] A liquid crystal LC (LC) is used to generate images corresponding to display data. Display data can be received via a voltage detection circuit and converted into a corresponding display voltage, which is then applied to the first liquid crystal electrode of the LC. The transmittance of the LC is controlled based on the voltage difference between the display voltage of the first liquid crystal electrode and the liquid crystal reference voltage of the second liquid crystal electrode, thereby enabling the display of different data content.

[0049] At the first moment when the sensing electrode plate detects the fingerprint signal, the first controllable switch K1 can drive the sensing electrode plate or the first liquid crystal electrode of the liquid crystal (the two are connected and have the same voltage) to the first preset voltage. For example, the second switch pin of the first controllable switch K1 is connected to a voltage source, and the voltage of the voltage source is the first preset voltage.

[0050] At the second moment, the first controllable switch K1 is opened, and the second controllable switch K2 is closed, switching the second liquid crystal electrode of the liquid crystal LC to a preset high voltage VGH. At this time, the distance between the sensing electrode and the finger affects the size of the sensing capacitance. The size of the sensing capacitance causes a change in the voltage of the first liquid crystal electrode of the liquid crystal LC. This voltage change is detected by the voltage detection circuit 3, and the current change caused by the voltage is detected by the current detection circuit 2, thereby effectively detecting fingerprint information.

[0051] To accurately detect voltage changes, the sensing electrode plate can be discharged and reset via a first control signal before voltage detection. This can be achieved by closing a first controllable switch, ensuring that the voltage on the sensing electrode plate is the same as the liquid crystal off-state voltage VGL at the second switch pin of the first controllable switch.

[0052] After the reset is complete, the first controllable switch K1 can be disconnected, causing the second controllable switch to close. The potential of the second liquid crystal electrode in the liquid crystal LC rises to the high voltage VGH of the second control signal, and the voltage of the sensing electrode plate SC increases. Controlling the second controllable switch to close allows the voltage detection circuit to perform fingerprint detection based on voltage change information. In this case, because the fingerprint's position and the sensing capacitance formed by the sensing electrode plate differ, the sensing capacitance Ct (the capacitance formed by the sensing electrode plate and the finger) and the liquid crystal capacitance C... LC Therefore, by using voltage division with capacitors of different sizes for detection, the concavity and convexity information of the fingerprint at different pixels can be obtained, thereby determining the fingerprint information.

[0053] The current detection circuit may include a fifth controllable switch K5. The control pin of the fifth controllable switch K5 is connected to the second liquid crystal electrode of the liquid crystal LC. The first switch pin of the fifth controllable switch K5 is connected to ground. The second switch pin of the fifth controllable switch K5 is used to determine the corresponding current signal according to the voltage of the second liquid crystal electrode of the liquid crystal LC.

[0054] like Figure 1 As shown, the voltage detection circuit 3 may include a driving circuit 21 and a detection circuit 22. The driving circuit 21 may include a digital-to-analog converter circuit and a first integrated operational amplifier U1. The digital-to-analog converter circuit converts display data into a display voltage, and the first integrated operational amplifier U1 amplifies the converted display voltage to drive the sensing electrode plate to a predetermined voltage.

[0055] The detection circuit 22 includes a second integrated operational amplifier U2, a feedback capacitor Cf, a fourth controllable switch K4, and an analog-to-digital converter circuit. The feedback capacitor Cf and the fourth controllable switch K4 are connected in parallel. The first end of the feedback capacitor Cf is connected to the negative input terminal of the second integrated operational amplifier U2, and the second end of the feedback capacitor Cf is connected to the output terminal of the second integrated operational amplifier U2. The output terminal of the second integrated operational amplifier U2 is connected to the analog-to-digital converter circuit. The control pin of the fourth controllable switch K4 is used to control the discharge of the feedback capacitor Cf according to the reset signal. After the discharge is completed, the first control signal, which serves as the reset signal, ends, the third controllable switch is opened, and the charge driven by the sub-pixel circuit is transferred to the output of the second integrated operational amplifier U2. The fingerprint detection result is determined by the output voltage generated by U2.

[0056] Among the possible implementations, such as Figure 2 The diagram shown is a structural schematic of another liquid crystal display circuit provided in an embodiment of this application. Figure 1 Compared to the liquid crystal display circuit shown, the current detection circuit includes a fifth controllable switch K5 and a sixth controllable switch K6. The control pin of the fifth controllable switch K5 is connected to the second liquid crystal electrode of the liquid crystal LC, and the first switch pin of the fifth controllable switch K5 is connected to ground. The second switch pin of the fifth controllable switch K5 is used to determine, via the sixth controllable switch K6, whether to output a current signal determined by the voltage of the second liquid crystal electrode of the liquid crystal LC. The control pin of the sixth controllable switch K6 is used to receive a second control signal. That is, the first switch pin of the sixth controllable switch K6 is connected to the second switch pin of the fifth controllable switch K5, and the second switch pin of the sixth controllable switch is used to determine the corresponding current signal based on the voltage of the second liquid crystal electrode of the liquid crystal.

[0057] like Figure 3 The diagram shown is a control timing diagram of a liquid crystal display circuit provided in an embodiment of this application. Figure 3 As shown, the signals used to control the LCD display include a row scan signal and a reset signal. The fingerprint detection area of ​​the LCD display can include both a display state and a fingerprint detection state, depending on the operating state. When the LCD display is in display state, no finger is detected pressing on the screen, and fingerprint detection is not required. Therefore, a reset signal is not needed to control the voltage reset of the sensing electrode plate. In this case, the display data can be converted into a display voltage through the voltage detection circuit, and the image corresponding to the data can be displayed normally.

[0058] like Figure 1As shown, when the LCD screen is in fingerprint detection mode, a reset signal needs to be output to reset the voltage of the sensing electrode plate before driving it to a predetermined voltage. This is achieved by controlling the first controllable switch to close via the first control signal (SCAN(n-1)), thus resetting the voltage of the sensing electrode plate.

[0059] Meanwhile, in the voltage detection circuit, since a reset is required for each detection, the detection circuit can control the fourth controllable switch to close based on a fixed reset signal, thereby discharging the feedback capacitor and making the detection results more accurate.

[0060] After resetting the sensing electrode plate and feedback capacitor, the second control signal (SCAN(n)) can be used, i.e. Figure 2 The scan signal in the nth row controls and drives the second switch to close. Due to charge conservation, the charge driven by the sub-pixel circuit is transferred to the output of the second integrated operational amplifier U2. Based on the voltage change information caused by the change in the sensing capacitance, the output voltage generated by the second integrated operational amplifier U2 is:

[0061]

[0062] Wherein, is the output voltage of the second integrated operational amplifier U2, VREF is the predetermined voltage driven by the first liquid crystal electrode after the second controllable switch is closed, VGL is the preset liquid crystal turn-off voltage, and Ct is the sensing capacitance, i.e., the capacitance formed by the sensing electrode plate and the finger. LC Cf is the self-capacitance of the liquid crystal, i.e., the capacitance of the liquid crystal itself. Cf is the feedback capacitor. Based on the magnitude of the output voltage, the fingerprint detection result at the corresponding position of the sub-pixel circuit can be determined.

[0063] When detecting fingerprint information using the voltage detection circuit, assuming the first control signal is the (n-1)th row scan signal, at time (n-1), the first control signal is at a high level VGH, controlling the first controllable switch to close, and resetting the voltage Vx of the sensing electrode plate SC to a predetermined first preset voltage VRST (adjustable voltage). At this time, the current generated by the drain and collector of the third thin-film transistor via the third controllable switch is current I, and the magnitude of the current is I = g. m VRST, where gm is transconductance.

[0064] At time n, when the nth row scan signal (corresponding to the second control signal) is activated, the potential of the nth row scan signal changes from VGL to VGH, causing a change in the voltage Vx of the sensing electrode plate SC. At this time, the current generated by the drain-collector connection of the third thin-film transistor is Where Ct is the sensing capacitance and Cb is the unit capacitance. The change in current is: Therefore, the magnitude of the current change is related to the sensing capacitance Ct. A larger sensing capacitance results in a smaller current change, and a smaller sensing capacitance results in a larger current change. Since the sensing capacitance is also related to the distance between the finger and the sensing electrode plate, a smaller distance results in a smaller sensing capacitance, and a larger distance results in a larger sensing capacitance. Therefore, the change in distance can be determined based on the magnitude of the sensing capacitance.

[0065] When the (n+1)th row scanning signal starts working, the (n+1)th row scanning signal is at a high level. At this time, the (n+1)th row scanning signal SCAN(n+1) serves as the third control signal, controlling the third controllable switch, which can close the third thin-film transistor TFT3 and reset the voltage Vx of the sensing electrode plate to the preset voltage VRST.

[0066] In a possible implementation, when the display and fingerprint sensing panel includes m*n sub-pixel circuits, the drive control chip can output a line-by-line scan signal scan<1~n>, a reset signal reset<1~n>, and a data signal data<1~n> that outputs different data voltages according to different working states.

[0067] Since the row scan signal and reset signal each consist of n signals, a single row scan signal and reset signal can be output through different pins of the driver control chip. However, for high-resolution displays, this requires too many pins, increasing the chip area. To reduce pin consumption, the reset signal's pin consumption can be eliminated, such as... Figure 4 As shown, the pin connecting the reset signal in the nth row sub-pixel is connected to the row scan signal of the (n-1)th row. Since the high-level signal (liquid crystal turn-on voltage) of the (n-1)th row row scan signal precedes the high-level signal of the nth row row scan signal, connecting the (n-1)th row row scan signal to the input pin of the reset signal in the nth row sub-pixel circuit effectively completes the reset operation before the nth row row scan signal performs fingerprint detection on the nth row sub-pixel. This includes the discharge reset of the feedback capacitor and the voltage reset of the first liquid crystal electrode.

[0068] In a further optimized implementation, to further reduce the number of pins on the driver control chip, a shift register can be used to generate the row scan signal. The driver control chip only needs to output the control signals of the shift register, including the start signal and the clock signal, to generate the row scan signal, which can further significantly reduce the number of pins on the driver control chip.

[0069] Figure 6 This is a schematic diagram illustrating the implementation process of a liquid crystal display method provided in an embodiment of this application. Figure 6 As shown, this method is based on Figure 1 The liquid crystal display circuit shown in the figure, the method includes:

[0070] In S601, the pixel sub-circuit is reset by the first control signal, so that the first liquid crystal electrode is reset to the first preset voltage, and the voltage detection circuit is reset.

[0071] The first control signal is used to close the first controllable switch, reset the potential of the first liquid crystal electrode, and reset the voltage of the first liquid crystal electrode to a preset liquid crystal turn-off voltage, or to the same potential as the second liquid crystal electrode. The first control signal is also used to close the fourth controllable switch, reset the feedback capacitor in the detection circuit, and discharge the feedback capacitor, so as to facilitate the calculation of the output voltage of the second integrated operational amplifier based on the discharged feedback capacitor.

[0072] In S602, the second liquid crystal electrode of the liquid crystal is connected to a third preset voltage by a second control signal, and the second controllable switch is closed by the second control signal. The voltage detection circuit performs fingerprint detection based on the output voltage determined by charge conservation. The current detection circuit is used to detect the current change caused by the change in the sensing capacitance of the sensing electrode plate.

[0073] The second controllable switch can be closed by the second control signal, allowing the driving voltage of the voltage detection circuit to be applied to the first liquid crystal electrode. When the first liquid crystal electrode is driven to a predetermined voltage VREF, due to charge conservation, the fingerprint detection result of the sub-pixel can be determined based on the charge transfer from the sub-pixel circuit to the output of the second integrated operational amplifier, and the calculated output voltage detected by the voltage detection circuit. The fingerprint detection result of the sub-pixel can also be determined based on the current change information of the drain of the fourth controllable switch (fourth thin-film transistor) caused by the first and second control signals.

[0074] In a possible implementation, a third control signal can also be received, and a third controllable switch can be closed based on the third control signal to reset the first liquid crystal electrode of the liquid crystal to a second preset voltage.

[0075] Figure 6 The liquid crystal display method shown is similar to... Figure 1 The corresponding LCD display circuit is shown below, and will not be described again here.

[0076] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0077] Figure 7 This is a schematic diagram of a liquid crystal display device provided in an embodiment of this application. The device includes:

[0078] The reset unit is used to control the pixel sub-circuit to reset via a first control signal, so that the first liquid crystal electrode is reset to a first preset voltage, and to control the voltage detection circuit to reset.

[0079] The driving detection unit is used to connect the second liquid crystal electrode of the liquid crystal to a third preset voltage through a second control signal, and to control the second controllable switch to close through the second control signal. The voltage detection circuit performs fingerprint detection based on the output voltage determined by charge conservation. The current detection circuit is used to detect the current change caused by the change in the sensing capacitance of the sensing electrode plate.

[0080] Figure 7 The liquid crystal display device shown is, and Figure 6 The liquid crystal display method shown corresponds to this.

[0081] Figure 8 This is a schematic diagram of a liquid crystal display device provided in an embodiment of this application. Figure 8 As shown, the liquid crystal display device 8 of this embodiment includes: a processor 80, a memory 81, and a computer program 82, such as a liquid crystal display program, stored in the memory 81 and executable on the processor 80. When the processor 80 executes the computer program 82, it implements the steps in the various liquid crystal display method embodiments described above. Alternatively, when the processor 80 executes the computer program 82, it implements the functions of each module / unit in the various device embodiments described above.

[0082] For example, the computer program 82 may be divided into one or more modules / units, which are stored in the memory 81 and executed by the processor 80 to complete this application. The one or more modules / units may be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program 82 in the liquid crystal display device 8.

[0083] The liquid crystal display device may include, but is not limited to, a processor 80 and a memory 81. Those skilled in the art will understand that... Figure 8 This is merely an example of the liquid crystal display device 8 and does not constitute a limitation on the liquid crystal display device 8. It may include more or fewer components than shown, or combine certain components, or different components. For example, the liquid crystal display device may also include input / output devices, network access devices, buses, etc.

[0084] The processor 80 may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0085] The memory 81 can be an internal storage unit of the liquid crystal display device 8, such as a hard disk or memory of the liquid crystal display device 8. The memory 81 can also be an external storage device of the liquid crystal display device 8, such as a plug-in hard disk, smart media card (SMC), secure digital card (SD), flash card, etc., equipped on the liquid crystal display device 8. Furthermore, the memory 81 can include both internal storage units and external storage devices of the liquid crystal display device 8. The memory 81 is used to store the computer program and other programs and data required by the liquid crystal display device. The memory 81 can also be used to temporarily store data that has been output or will be output.

[0086] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0087] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0088] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0089] In the embodiments provided in this application, it should be understood that the disclosed devices / terminal equipment and methods can be implemented in other ways. For example, the device / terminal equipment embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling or direct coupling or communication connection may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0090] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0091] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0092] If the integrated module / unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can also be implemented by hardware related to computer program instructions. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. It should be noted that the content included in the computer-readable medium can be appropriately added or removed according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electrical carrier signals and telecommunication signals.

[0093] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application 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 this application, and should all be included within the protection scope of this application.

Claims

1. A liquid crystal display circuit, characterized by comprising: The liquid crystal display circuit comprises a sub-pixel circuit, a voltage detection circuit and a current detection circuit, the sub-pixel circuit comprises a sensing electrode plate, a liquid crystal, a first controllable switch, a second controllable switch and a third controllable switch, wherein: The sensing electrode plate is connected with a first switch pin of the first controllable switch, a first switch pin of the second controllable switch and a first switch pin of the third controllable switch respectively, and the sensing electrode plate and a first liquid crystal electrode of the liquid crystal share the same electrode plate; A second switch pin of the first controllable switch is used for connecting a preset voltage source, and the first controllable switch is used for resetting the first liquid crystal electrode of the liquid crystal to the first preset voltage according to a first control signal; A second liquid crystal electrode of the liquid crystal is used for receiving a second control signal, the second control signal is used for providing voltage change information for the voltage detection circuit and current change information for the current detection circuit; A second switch pin of the second controllable switch is connected with the voltage detection circuit, and the second controllable switch is used for transmitting change information of a sensing capacitor of the sensing electrode plate to the voltage detection circuit for fingerprint detection; A second switch pin of the third controllable switch is used for receiving a reset signal to reset the first liquid crystal electrode of the liquid crystal to a second preset voltage.

2. The liquid crystal display circuit according to claim 1, wherein The current detection circuit comprises a driving circuit and a detection circuit, the driving circuit is used for converting display data into a driving voltage and driving the first liquid crystal electrode to a predetermined voltage, and the detection circuit is used for detecting a charge amount of the driving circuit driven to the predetermined voltage, and performing fingerprint detection according to the charge amount.

3. The liquid crystal display circuit according to claim 2, wherein The driving circuit comprises a digital-to-analog conversion circuit and a first integrated operational amplifier, the digital-to-analog conversion circuit is used for converting display data into a display voltage, and the first integrated operational amplifier is used for amplifying the display voltage and outputting a driving voltage.

4. The liquid crystal display circuit according to claim 2, wherein The detection circuit comprises a second integrated operational amplifier, a feedback capacitor, a fourth controllable switch and an analog-to-digital conversion circuit, the feedback capacitor and the fourth controllable switch are connected in parallel, a first end of the feedback capacitor is connected with a negative input end of the second integrated operational amplifier, a second end of the feedback capacitor is connected with an output end of the second integrated operational amplifier, the output end of the second integrated operational amplifier is connected with the analog-to-digital conversion circuit, and a control pin of the fourth controllable switch is used for controlling the feedback capacitor to discharge according to a reset signal.

5. The liquid crystal display circuit according to claim 1, wherein A control end of the first controllable switch is used for receiving an n-1th row scanning signal in row-by-row scanning signals, a control end of the second controllable switch is used for receiving an nth row scanning signal in the row-by-row scanning signals, and a reset signal of the third controllable switch is an n+1th row scanning signal, wherein n is a natural number greater than 0.

6. The liquid crystal display circuit according to claim 1, wherein The current detection circuit comprises a fifth controllable switch, a control pin of the fifth controllable switch is connected with the second liquid crystal electrode of the liquid crystal, a first switch pin of the fifth controllable switch is connected with the ground, and a second switch pin of the fifth controllable switch is used for determining a corresponding current signal according to a voltage of the second liquid crystal electrode of the liquid crystal.

7. The liquid crystal display circuit according to claim 1, wherein The current detection circuit comprises a fifth controllable switch and a sixth controllable switch, a control pin of the fifth controllable switch is connected with the second liquid crystal electrode of the liquid crystal, a first switch pin of the fifth controllable switch is connected with the ground, and a second switch pin of the fifth controllable switch is used for determining whether to output a current signal determined by the voltage of the second liquid crystal electrode of the liquid crystal through the sixth controllable switch, and a control pin of the sixth controllable switch is used for receiving a second control signal.

8. A liquid crystal display method, characterized by, The method is based on the liquid crystal display circuit according to any one of claims 1-6, and the method comprises: controlling the pixel sub-circuit to reset through a first control signal, so as to reset the first liquid crystal electrode to a first preset voltage, and controlling the voltage detection circuit to reset; the second liquid crystal electrode of the liquid crystal is connected to a third preset voltage through a second control signal, the second controllable switch is controlled to be closed through the second control signal, the voltage detection circuit performs fingerprint detection according to an output voltage determined according to the charge conservation, and the current detection circuit is used for detecting a current change caused by a change of a sensing capacitance of the sensing electrode plate.

9. The method of claim 8, wherein, The method further comprises: controlling the third controllable switch to be closed through a third control signal, so as to reset the first liquid crystal electrode of the liquid crystal to a second preset voltage.

10. A liquid crystal display device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, The processor executes the computer program to realize the steps of the method according to any one of claims 8-9.

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