Electronic devices

Abstract

The present disclosure is about an electronic device, including: a display screen and an optical fingerprint detection module arranged below the display screen; the optical fingerprint detection module includes a plurality of row control lines and a plurality of column data lines, a pixel is arranged at the intersection of any row control line and any column data line, a driving circuit connected to the plurality of row control lines and a power supply circuit for supplying power to the driving circuit; the power supply circuit is used to provide a first driving voltage to the driving circuit during the scanning stage, and the driving circuit is used to turn on each row of pixels in sequence during the scanning stage; the power supply circuit is used to provide a second driving voltage to the driving circuit during the reset stage, and the driving circuit is used to turn on each pixel during the reset stage; the second driving voltage is greater than the first driving voltage. This embodiment can reduce the resistance of the switching device in the pixel, which is conducive to reducing the time consumption of eliminating the charge in each pixel and improving the reset efficiency.

Description

Technical Field

[0001] The present disclosure relates to the field of control technology, and in particular to an electronic device. Background Art

[0002] Currently, more and more electronic devices use under-screen fingerprint solutions for unlocking, payment and other scenarios. Figure 1 When the display screen is an OLED display screen, the OLED self-luminescence encounters the finger and is reflected to the optical fingerprint module. The optical fingerprint module detects the image based on the reflected light to obtain the fingerprint.

[0003] Figure 1 The optical fingerprint module shown includes an optical path and a sensor, wherein the circuit of the sensor is as follows Figure 2 As shown, the sensor includes an optical fingerprint sensing area and a non-sensing area. The optical fingerprint sensing area includes a plurality of pixel circuits, each pixel circuit includes a switching device TFT and a photosensitive diode PD; the non-sensing area includes a gate drive chip (GOA) and a data reading chip (ROIC).

[0004] Figure 3 The circuit architecture and timing of a pixel reading charge are shown in FIG. Figure 3 , triggering the RST switch to discharge the capacitor CF, i.e., resetting the operational amplifier. And read the output value Vout1 of the output terminal Vout of the operational amplifier at time t1. After a period of time, the PD can collect light energy and convert it into capacitance. After turning on the GOA to reach this line of the PD, the signal at the SEL position is effectively turned on, and the output value Vout2 of the output terminal Vout of the operational amplifier is read at time t2. Then, the two values ​​are subtracted to obtain the light signal collected by the PD. The PD signal of the entire sensing area can restore the fingerprint. In other words, Figure 3 In the illustrated architecture, the photodiode PD is a key device, and the accumulated photocharge number (sensitivity) thereof determines the quality of the entire fingerprint image.

[0005] In practical applications, the photodiode PD adopts an a-Si PIN structure and is manufactured by the chemical vapor deposition (CVD) method. In this process, some electrons in the PD will be restricted, resulting in residual photocharges. That is, the read data will include the last accumulated charge, affecting the detection accuracy. Summary of the invention

[0006] The present disclosure provides an electronic device to solve the deficiencies of the related art.

[0007] According to a first aspect of an embodiment of the present disclosure, an electronic device is provided, comprising a display screen and an optical fingerprint detection module arranged below the display screen; the optical fingerprint detection module comprises a plurality of row control lines and a plurality of column data lines, a pixel is arranged at the intersection of any row control line and any column data line, a driving circuit connected to the plurality of row control lines, and a power supply circuit for supplying power to the driving circuit;

[0008] The power supply circuit is used to provide a first driving voltage to the driving circuit during a scanning phase, and the driving circuit is used to sequentially turn on each row of pixels during the scanning phase to collect light signals;

[0009] The power supply circuit is used to provide a second driving voltage to the driving circuit in a reset phase, and the driving circuit is used to turn on each pixel in the reset phase to eliminate the charge in each pixel;

[0010] The second driving voltage is greater than the first driving voltage.

[0011] Optionally,

[0012] The power supply circuit comprises a power supply, a charge pump circuit and a voltage stabilizing circuit; the charge pump circuit is connected to the power supply and the voltage stabilizing circuit respectively; the power supply is used to provide a preset voltage;

[0013] The charge pump circuit is used to boost the preset voltage to a third driving voltage;

[0014] The voltage stabilizing circuit is used for converting the third driving voltage into the first driving voltage during the scanning phase and converting the third driving voltage into the second driving voltage during the resetting phase.

[0015] Optionally, the voltage stabilizing circuit includes an operational amplifier, a transistor, a first resistor, a second resistor and a switch; the inverting input terminal of the operational amplifier receives a preset reference voltage, the non-inverting input terminal of the operational amplifier is connected to the first end of the second resistor, and the output terminal of the operational amplifier is respectively connected to the control electrode of the transistor and the first end of the switch;

[0016] The second end of the switch is grounded;

[0017] The first electrode of the transistor is connected to the output end of the charge pump circuit, and the second electrode of the transistor is connected to the first end of the first resistor and the output end of the voltage stabilizing circuit respectively;

[0018] The first end of the second resistor is connected to the second end of the first resistor, and the second end of the second resistor is grounded.

[0019] Optionally, the optical fingerprint detection module further includes a data driving circuit; the data driving circuit includes a power supply and a bias switch, and the power supply is respectively connected to each column data line through the bias switch;

[0020] The power supply is used to provide a reverse bias voltage and a forward bias voltage; the reverse bias voltage is a negative value, and the forward bias voltage is a positive value;

[0021] The bias switch is used to provide a reverse bias voltage to the data line during a scan phase and to provide a forward bias voltage to the data line during a reset phase.

[0022] Optionally, the optical fingerprint detection module further includes a charge elimination circuit; the charge elimination circuit is used to provide a forward bias voltage to pixels in an on state during a reset phase to eliminate the charge in each pixel.

[0023] Optionally, the charge elimination circuit includes a bias switch and a bias power supply; the bias power supply can provide a forward bias voltage and a reverse bias voltage; wherein the forward bias voltage is used to put the photodiode in the pixel in a forward bias state, and the reverse bias voltage is used to put the photodiode in the pixel in a reverse bias state;

[0024] The bias switch is used to provide a reverse bias voltage to the pixels in the on state during the scanning phase, and is used to provide a forward bias voltage to the pixels in the on state during the resetting phase.

[0025] Optionally, the charge elimination circuit also includes a first switch and a preset power supply; the first end of the first switch is connected to the data line of the column, the second end of the first switch is connected to the preset power supply, and the control end of the first switch is connected to the driving circuit; the first switch is used to connect the data line of the column and the preset power supply upon receiving a control signal from the driving circuit.

[0026] Optionally, the preset power supply includes at least one of the following: ground, a negative voltage source and a current source.

[0027] Optionally, the driving circuit includes a first driving unit and a second driving unit;

[0028] The first driving unit is used to output control signals to each row control line in sequence during the scanning phase;

[0029] The second driving unit is used to output control signals to each group of control lines in sequence during the reset phase.

[0030] Optionally, the optical fingerprint detection module further includes a data reading circuit, the data reading circuit includes a plurality of data reading units, and each data reading unit is connected to a data line in a one-to-one correspondence;

[0031] The data reading unit includes an operational amplifier and a feedback capacitor; the inverting input terminal of the operational amplifier is respectively connected to the positive terminal of the data line of the column and the first end of the feedback capacitor, the non-inverting input terminal of the operational amplifier is grounded, and the output terminal of the operational amplifier is connected to the second end of the feedback capacitor.

[0032] Optionally, the data reading circuit further includes an analog-to-digital converter, which is connected to each data reading unit respectively and is used to perform analog-to-digital conversion on the pixel data output by each data reading unit.

[0033] The technical solution provided by the embodiments of the present disclosure may have the following beneficial effects:

[0034] It can be seen from the above embodiments that in the embodiments of the present disclosure, a power supply circuit is provided for the driving circuit, which can provide a first driving voltage to the driving circuit during the scanning stage and a second driving voltage to the driving circuit during the reset stage, and the second driving voltage is greater than the first driving voltage. In this way, when the driving circuit drives each pixel during the reset stage, the higher second driving voltage can be provided to each pixel, which can reduce the resistance of the switching device in the pixel, which is beneficial to reducing the time consumed in eliminating the charge in each pixel and improving the reset efficiency.

[0035] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0037] Figure 1 It is a schematic diagram of the spatial position relationship between an optical fingerprint detection module and a display screen shown in the related art.

[0038] Figure 2 It is a circuit structure diagram of an optical fingerprint detection module shown in the related art.

[0039] Figure 3 is a schematic diagram of a charge collection circuit including one pixel shown in the related art.

[0040] Figure 4 FIG. 1 is a schematic diagram of a circuit for clearing charges of a photodiode shown in the related art.

[0041] Figure 5 FIG. 1 is a block diagram of a power supply circuit for supplying power to a driving circuit shown in the related art.

[0042] Figure 6 The diagram is a schematic diagram of a circuit structure of an electronic device according to an exemplary embodiment.

[0043] Figure 7 is a block diagram of a power supply circuit according to an exemplary embodiment.

[0044] Figure 8 is a block diagram of another power supply circuit according to an exemplary embodiment.

[0045] Fig. 9 yes Figure 8 Schematic diagram of the operating timing of the mode switch shown.

[0046] Fig.10 is a block diagram of yet another power supply circuit according to an exemplary embodiment.

[0047] Fig.11 yes Fig.10 Schematic diagram of the operating timing of the mode switch shown.

[0048] Fig.12 The diagram is a schematic diagram of a circuit structure of an electronic device according to an exemplary embodiment.

[0049] Fig.13 is a schematic diagram of a logic structure of a driving circuit according to an exemplary embodiment.

[0050] Fig.14 It is a working timing diagram according to an exemplary embodiment.

[0051] Fig.15 is a schematic diagram of a circuit structure of another electronic device according to an exemplary embodiment.

[0052] Fig.16 It is a schematic diagram showing that a current source is arranged inside a data acquisition circuit as shown in the related art.

[0053] Fig.17 It is a schematic diagram showing that a current source is arranged outside a data acquisition circuit in the related art.

[0054] Fig.18 It is a working timing diagram according to an exemplary embodiment.

[0055] Fig.19 is a schematic diagram of a circuit structure of another electronic device according to an exemplary embodiment.

[0056] Fig. 20It is a schematic diagram showing an application scenario according to an exemplary embodiment.

[0057] Fig.21 It is a block diagram of an electronic device according to an exemplary embodiment. DETAILED DESCRIPTION

[0058] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described below by way of example do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices consistent with some aspects of the present disclosure as detailed in the appended claims.

[0059] In order to eliminate the residual charge in the photodiode PD in the pixel, some methods are used in the related art to clear the charge in the PD. Figure 4 , switch Bias from the receiving voltage -V to the receiving voltage +V, so that the PD is forward-conducted. In the above scheme, the PD discharge speed is related to the RC charge and discharge time, where R refers to the on-resistance of the switching device TFT, and C refers to the feedback capacitor C F Since the on-resistance of the switching device TFT is large, a large turn-on voltage is required. Figure 5 , the lower supply voltage V LO , which is increased to voltage V by a charge pump (CP) CP , and then stabilized to voltage V by a low-dropout regulator (LDO) GH Then it is provided to the gate driver chip (GOA) for use. However, in order to reduce the voltage V CP The ripple on the LDO output voltage V GH will be less than the voltage V CP , causing the on-resistance of the switching device TFT to become larger than the expected resistance, thereby prolonging the time required to clear the charge in the PD.

[0060] In order to accelerate the elimination of the charge in the PD, an embodiment of the present disclosure provides an electronic device, which may include a display screen and an optical fingerprint detection module disposed below the display screen. Figure 6 The optical fingerprint detection module includes several rows of control lines (G1~G N ) and several columns of data lines (R O1 ~R ON ), a pixel is set at the intersection of any row control line and any column data line, a driving circuit (GOA) connected to several row control lines and a power supply circuit for supplying power to the driving circuit.

[0061] Continue to see Figure 6 The power supply circuit is used to provide a first driving voltage to the driving circuit during the scanning stage, and the driving circuit is used to turn on each row of pixels (such as the switching device TFT in the pixel) in turn during the scanning stage to collect light signals; and the power supply circuit is used to provide a second driving voltage to the driving circuit during the reset stage, and the driving circuit is used to turn on each pixel during the reset stage to eliminate the charge in each pixel; the second driving voltage is greater than the first driving voltage.

[0062] At this point, in the embodiment of the present disclosure, a power supply circuit is provided for the driving circuit, which can provide a first driving voltage to the driving circuit during the scanning stage and a second driving voltage to the driving circuit during the reset stage, and the second driving voltage is greater than the first driving voltage. In this way, the driving circuit can provide a higher second driving voltage to each pixel when driving each pixel during the reset stage, which can reduce the resistance of the switching device in the pixel, which is beneficial to reducing the time consumed in eliminating the charge in each pixel and improving the reset efficiency.

[0063] In one embodiment, see Figure 7 The power supply circuit includes a power supply 71, a charge pump circuit 72 and a voltage stabilizing circuit 73; the charge pump circuit 72 is connected to the power supply 71 and the voltage stabilizing circuit 73 respectively; the power supply 71 is used to provide a preset voltage V0; the charge pump circuit 72 is used to boost the preset voltage V0 to a third driving voltage V3; the voltage stabilizing circuit 73 is used to convert the third driving voltage V3 into a first driving voltage V1 during the scanning stage and convert the third driving voltage V3 into a second driving voltage V2 during the reset stage.

[0064] In this embodiment, in the scanning stage, the voltage stabilizing circuit 73 can operate in a voltage stabilizing state, that is, it is used to eliminate the ripple in the third driving voltage V3, so that the first driving voltage V1 with a certain fluctuation can be obtained, and the fluctuation range is [V1', V1"]. Among them, V1' and V1" are the minimum and maximum values ​​of the first driving voltage V1 respectively. In the reset stage, the voltage stabilizing circuit 73 can operate in a switching state. Because it has a certain resistance, the voltage stabilizing circuit 73 can perform a certain voltage division on the third driving voltage V3 and output the second driving voltage V2.

[0065] It is understandable that, since the voltage stabilizing circuit 73 works in the switching state, its internal resistance will be less than the preset resistance threshold, or can be ignored, so the second driving voltage V2 can be approximately equal to the third driving voltage V3. In other words, when the voltage stabilizing circuit 73 works in the reset state, it can output a larger driving voltage and provide it to the switching device in the pixel, which is beneficial to reduce the resistance value of the switching device in the pixel, thereby reducing the time consumed for RC charging and discharging, that is, the accumulated charge in the photodiode can be eliminated more quickly.

[0066] In one example, see Figure 8The voltage stabilizing circuit also includes a mode switch SW0, whose working sequence is as follows: Fig. 9 As shown. In the reset stage, the mode switch SW0 receives a high-level signal and closes, at which time the voltage regulator circuit 73 can be short-circuited, which can be understood as the voltage regulator outputting the second drive voltage V2 (approximately equal to V3). In the scan stage, the mode switch SW0 receives a low-level signal and opens, at which time the voltage regulator circuit 73 can output the first drive voltage V1.

[0067] In another example, see Fig.10 The voltage stabilizing circuit 73 includes an operational amplifier OPA, a transistor M D , a first resistor R1, a second resistor R2 and a switch SW1; an inverting input terminal of the operational amplifier OPA receives a preset reference voltage V REF , operational amplifier V REF The positive phase input terminal of the operational amplifier OPA is connected to the first end of the second resistor R2, and the output end of the operational amplifier OPA is connected to the transistor M D The control electrode of the transistor M is connected to the first end of the switch SW1; the second end of the switch SW1 is grounded GND; D The first electrode of the transistor M is connected to the output terminal of the charge pump circuit 72. D The second electrode is connected to the first end of the first resistor R1 and the output end of the voltage stabilizing circuit 73 respectively; the first end of the second resistor R2 is connected to the second end of the first resistor R1, and the second end of the second resistor R2 is grounded GND.

[0068] It should be noted that Fig.10 The transistor M in the voltage stabilizing circuit 73 is shown D When using P-type transistors, transistor M D A low-level start-up voltage is required, so the second electrode of the switch SW1 is grounded. D When using N-type transistors, transistor M D A high level of starting voltage is required, so the second pole of the switch SW1 can be connected to the power supply. The technicians can make a selection according to the specific scenario, and the corresponding solution falls within the protection scope of the present disclosure.

[0069] In this example, the operating timing of the switch SW1 in the voltage stabilizing circuit 73 can be as follows: Fig.11 See Fig.11 In the reset phase, the switch SW1 receives a high level signal and closes. At this time, the transistor M D Working in the linear region (or variable resistance region), the transistor M D Equivalent to a switch, at this time the transistor M D The second driving voltage V2 can be output. In the scanning stage, the switch SW1 receives a low level signal and is turned on. At this time, the transistor MD Working in the saturation region, it is equivalent to an amplifier. At this time, transistor M D When turned on, the first driving voltage V1 can be output. The first resistor R1, the second resistor R2 and the operational amplifier OPA form a negative feedback circuit, and the first resistor R1 and the second resistor R2 form a voltage divider circuit. The positive input terminal of the operational amplifier OPA obtains the divided voltage V of the second resistor R2. R2 and with the reference voltage V REF The difference voltage is obtained by comparison and provided to transistor M D The control electrode of transistor M D The first driving voltage V1 is stabilized.

[0070] In one embodiment, the optical fingerprint detection module further includes a charge elimination circuit, which is used to provide a forward bias voltage to the pixels in the on state during the reset phase to eliminate the charge in each pixel. Fig.12 , the charge elimination circuit includes a power supply and a bias switch Bias, the power supply is connected to each column data line through the bias switch Bias; the power supply is used to provide a reverse bias voltage -V and a forward bias voltage +V; the reverse bias voltage is a negative value, and the forward bias voltage is a positive value. In other words, the forward bias voltage is used to make the photodiode in the pixel in a forward biased state, and the reverse bias voltage is used to make the photodiode in the pixel in a reverse biased state. The bias switch Bias is used to turn on the power supply and the data line during the scanning stage to provide the data line with a reverse bias voltage -V, and to turn on the power supply and the data line during the reset stage to provide the data line with a forward bias voltage +V. In this way, in this embodiment, by switching the bias switch Bias to the forward bias voltage +V, the photodiode PD can be in a forward biased state, thereby quickly eliminating the charge accumulated in the PD.

[0071] Continue to see Figure 6 The optical fingerprint detection module also includes a data reading circuit ROIC connected to a plurality of columns of data lines; the data reading circuit ROIC is used to read the pixel data of each pixel during the scanning phase.

[0072] Considering that the time used for resetting each row of pixels in the reset phase in the related art is TA, the maximum available time for each group of pixels in the reset phase in this example is TA*N / M. In practical applications, the time used for each group of pixels in the reset phase in this embodiment is TB, where TB can be determined based on the actual time used for the pixel to eliminate the charge, such as 2TA, 3TA, that is, the value range of TB is (TA, TA*N / M). That is to say, in this embodiment, by eliminating the charge of each column of pixels, the time TB used for eliminating the charge can be made greater than the time TA used in the related art, ensuring that the photodiode PD in the pixel has enough time to eliminate the charge; and, in this embodiment, TB is less than TA*N / M, which can also reduce the time used for each group of pixels to eliminate the charge, which is beneficial to improving the efficiency of charge elimination.

[0073] In order to achieve charge elimination of a single row or a single group of controlled pixels, the driving circuit GOA in this example may include a first driving unit and a second driving unit. The first driving unit is used to output control signals to each row of control lines in sequence during the scanning phase, and the second driving unit is used to output control signals to each group of control lines in sequence during the reset phase. Fig.13 FIG. 1 is a schematic diagram of a circuit structure of a driving circuit GOA according to an exemplary embodiment. Fig.13 , the optical fingerprint detection module can control the multiplexer MUX to switch through the control terminal CON:

[0074] In the scanning stage, the driving circuit GOA can output the first level through the control terminal CON, so that each MUX switches to the first input terminal. At this time, the driving signal of the shift register SR1-(1~N+1) can pass through the first input terminal of MUX1~M and output to the Gate terminal 1~M, so that single-row control of pixels can be achieved.

[0075] In the reset phase, the driving circuit GOA can output the second level through the control terminal CON, so that each MUX switches to the second input terminal. At this time, the driving signal of the shift register SR2-(1~N / M+1) can be output to Gate1~N through the second input terminal of the multiplexer MUX 1~N. Gate1~N is connected to the control line G1~N, so that a single group of pixels can be controlled.

[0076] It should be noted that technicians can select an implementation scheme of the driving circuit GOA according to specific scenarios. When single-row and single-group control can be achieved, the corresponding scheme falls within the protection scope of the present disclosure.

[0077] Combination Figure 12 to Figure 14 The working principle of the optical fingerprint detection module is described as follows:

[0078] In the reset phase, the driving circuit GOA controls the multiplexer MUX to switch to the respective second input terminals, so that the control signal output by the shift register SR2 is output to the Gate terminal via the second input terminal of the MUX in the row, so that the control line G corresponding to each group is high level, and the switch devices in the pixels of each group are turned on. At the same time, the reset switch RST is closed, and the switch K1 is closed, the photodiode PD is in a forward biased state, and the residual charge in the photodiode PD begins to disappear. After a certain time T#1 (such as the time TB mentioned above), the residual charge in the photodiode PD can be completely eliminated. In this way, in this stage, by increasing the duration of the reset phase, there can be sufficient time to eliminate the residual charge of the photodiode PD. At t1, the operational amplifier can detect the voltage at VN and output it, which is recorded as Vout1.

[0079] In the sensing stage, the control line G is at a low level, the reset switch RST is disconnected, and the switch K1 is disconnected. At this time, the photodiode PD can sense external light, forming a leakage current, making V N The voltage change at is Delta V.

[0080] In the scanning stage, the driving circuit GOA controls the multiplexer MUX to switch to the first input terminal of each row, so that the control signal output by the shift register SR1 is output to the Gate terminal through the first input terminal of the MUX in the row, that is, the control line G is at a high level. At this time, the switch devices in the pixels of each row are turned on in sequence according to the row order. The cathode of the photodiode PD is connected to the feedback capacitor C F and the inverting input terminal of the operational amplifier. At t2, the operational amplifier can detect the voltage at VN and output it, which is recorded as Vout2.

[0081] In this way, the analog-to-digital conversion unit in the data reading circuit can obtain the pixel data (Vout1 and Vout2) output by the data reading unit for analog-to-digital conversion, and Delta V can be obtained by subtracting the two.

[0082] Thus, the disclosed embodiment can group several rows of pixel data, and each group of pixels can be turned on in sequence during the reset phase to eliminate the charge in each pixel. Since each group of pixels corresponds to multiple rows, the time taken by each group of pixels to eliminate the charge can be increased, which is beneficial to eliminate the residual charge in the pixel; and, without exceeding the turn-on time in the related art (such as the product of the number of rows in each group and the turn-on time of each row), the time used in the reset phase can also be reduced.

[0083] In one embodiment, Fig.15 FIG. 1 is a schematic diagram showing a circuit structure of an electronic device according to an exemplary embodiment. Fig.15The electronic device includes a display screen and an optical fingerprint detection module disposed below the display screen. Fig.15 The optical fingerprint detection module includes several rows of control lines (G1~G N ) and several columns of data lines (R O1 ~R ON ), a pixel is set at the intersection of any row control line and any column data line, a driving circuit (GOA) connected to several row control lines and a data reading circuit (ROIC) connected to several column data lines.

[0084] Continue to see Fig.15 , while the pixel circuit remains unchanged, GOA uses the circuit in the related art or Fig.12 In the case of the circuit shown, the data reading circuit includes a plurality of data reading units, each of which is connected to a data line in a one-to-one manner; each of the data reading units includes a current source, which is used to eliminate the charge in the pixels in the column; or, the electronic device includes a current source corresponding to each of the data reading units in a one-to-one manner, and the current source is used to eliminate the charge in the pixels in the column. Fig.16 is a circuit structure diagram of a data reading circuit according to an exemplary embodiment, wherein a current source is disposed in the data reading circuit; Fig.17 The circuit structure diagram of a data reading circuit according to an exemplary embodiment is shown, and the current source is arranged outside the data reading circuit. In other words, the charge elimination circuit includes a current source, and the charge elimination circuit can be arranged inside or outside the data reading unit, and can be arranged according to the specific scenario, which is not limited here.

[0085] Take the current source in the charge elimination circuit being arranged outside the data reading unit as an example, see Fig.16 The data reading unit includes an operational amplifier A1, a feedback capacitor C F and current source I leak The inverting input terminal of the operational amplifier A1 is connected to the data line of the column, the current source I leak The positive terminal and feedback capacitor C F The first end of the operational amplifier A1 is connected to the ground, the non-inverting input terminal of the operational amplifier A1 is grounded, and the output terminal of the operational amplifier A1 is connected to the feedback capacitor C F The second end of the connection.

[0086] Take the current source in the charge elimination circuit as an example, which is set inside the data reading unit. Fig.17 The data reading unit includes an operational amplifier A1, a feedback capacitor C F , and the electronic device further includes a current source I leak The inverting input terminal of the operational amplifier A1 is connected to the data line of the column, the current source I leakThe positive terminal and feedback capacitor C F The first end of the operational amplifier A1 is connected to the ground, the non-inverting input terminal of the operational amplifier A1 is grounded, and the output terminal of the operational amplifier A1 is connected to the feedback capacitor C F The second end of the connection.

[0087] Combination Figure 15 to Figure 18 The working principle of the optical fingerprint detection module is described as follows:

[0088] In the reset phase, the drive circuit GOA outputs a control signal, that is, the control line G is high, and the switch devices in each row of pixels are turned on in sequence. In addition, the reset switch RST is closed, and the switch K1 is closed, at which time the photodiode PD is in a forward biased state. In this way, a discharge path can be formed between the current source, the control line and the photodiode PD, that is, the large current of the current source can eliminate the residual charge of the PD. At t1, the operational amplifier can detect the voltage at VN and output it, which is recorded as Vout1.

[0089] In the sensing stage, the control line G is at a low level, the reset switch RST is disconnected, and the switch K1 is disconnected. At this time, the photodiode PD can sense external light, forming a leakage current, making V N The voltage change at is Delta V.

[0090] In the scanning stage, the control line G is at a high level, and the switch device in the pixel is turned on; at the same time, the reset switch RST is turned off, and the switch K1 is turned off. At this time, the cathode of the photodiode PD is connected to the feedback capacitor C F and the inverting input terminal of the operational amplifier. At t2, the operational amplifier can detect the voltage at VN and output it, which is recorded as Vout2.

[0091] In this way, the analog-to-digital conversion unit in the data reading circuit can obtain the pixel data (Vout1 and Vout2) output by the data reading unit to perform analog-to-digital conversion, and Delta V can be obtained by subtracting the two.

[0092] Thus, the embodiments of the present disclosure can accelerate the elimination of residual charges in pixels by connecting a current source to the data line, utilizing the large current of the current source, thereby improving elimination efficiency and enhancing detection accuracy.

[0093] In one embodiment, Fig.19 FIG. 1 is a schematic diagram showing a circuit structure of an electronic device according to an exemplary embodiment. Fig.19 The electronic device includes a display screen and an optical fingerprint detection module disposed below the display screen. Fig.19 The optical fingerprint detection module includes several rows of control lines (G1~G N ) and several columns of data lines (R O1 ~R ON), a pixel is set at the intersection of any row control line and any column data line, a driving circuit (GOA) connected to several row control lines and a data reading circuit (ROIC) connected to several column data lines.

[0094] Continue to see Fig.19 The number of charge elimination circuits may be multiple, that is, each charge elimination circuit may correspond to each group one by one, or the number of charge elimination circuits may be one. The charge elimination circuit is used to provide a forward bias voltage to the pixels in the on state during the reset phase, so as to eliminate the charge in the pixels of the group. Fig.19 The shaded area shows a charge elimination circuit. Fig.19 The charge elimination circuit includes a first switch T1 and a preset power supply Vg. The first end of the first switch T1 is connected to the data line Rox of the column, the second end of the first switch T1 is connected to the preset power supply Vg, and the control end of the first switch T1 is connected to the driving circuit GOA; the first switch T1 is used to conduct the connection between the data line of the column and the preset power supply when receiving a control signal from the driving circuit GOA. The preset power supply includes at least one of the following: ground, a negative voltage source, and a current source.

[0095] Combination Fig.14 and Fig.19 , describing the working principle of the optical fingerprint detection module as follows:

[0096] In the reset stage, the driving circuit GOA outputs a control signal to make the control line G high level, and turns on the pixels of each row in order, so that the switch devices in the pixels of this row are turned on. At the same time, GOA also outputs a control signal to the first switch T1, so that the data line Rox is connected to the preset power supply Vg, and then connected to the pixels of the row through the data line, so that the residual charge of the photosensitive diode in each pixel can be eliminated in the forward direction through the preset power supply. The working methods of other stages can be seen in Fig.12 and Fig.15 The electronic equipment shown will not be described in detail here.

[0097] It can be seen that, by providing a charge elimination circuit for each group of pixels, the charge elimination circuit can accelerate the elimination of residual charges in the pixels, thereby improving elimination efficiency and detection accuracy. Moreover, in this embodiment, providing a charge elimination circuit for each group can eliminate residual charges for pixels that have read pixel data while other groups are reading pixel data, thereby further improving reset efficiency.

[0098] It should be noted that, in the absence of conflicts, technicians can combine the above-mentioned embodiments to obtain different solutions: combining group drive and current source, combining group drive and charge elimination circuit, combining current source and charge elimination circuit, and combining group drive, current source and charge elimination circuit. The above-mentioned solutions fall within the protection scope of the present disclosure.

[0099] The following describes the working process of electronic devices in combination with the application scenario of fingerprint unlocking:

[0100] See also Figure 1 and Fig. 20 , when the processor in the electronic device detects that the display screen of the electronic device is pressed, it can trigger the optical fingerprint detection module to collect the user's fingerprint for unlocking. The processor can control the switching switch in the voltage stabilizing circuit of the power supply circuit to turn on to output the second driving voltage, and provide the second driving voltage to the driving circuit GOA. The driving circuit turns on the pixels in sequence by row or by group. When the optical fingerprint detection module receives the control signal of the processor, it first switches to the reset stage. At this time, the optical fingerprint detection module can control the charge elimination circuit to provide a forward bias voltage to the pixel, and control the first switch to connect the preset power supply to the data line. At this time, the charge accumulated by the photodiode PD in the pixel is eliminated. After the set time is reached, the bias power supply is controlled to provide a reverse bias voltage, and the processor controls the switching switch in the voltage stabilizing circuit to turn off to output the first driving voltage or keep it on. At this time, the optical fingerprint detection module switches to continue to eliminate the charge accumulated by the photodiode PD in the pixel.

[0101] In the reset phase, the processor also detects whether the unlocking light spot is displayed on the display screen. When it is detected that the unlocking light spot does not appear, the switch is controlled to be turned on and off again to eliminate the charge. When it is detected that the unlocking light spot has appeared, the switch is controlled to be turned off so that the power supply circuit outputs the first driving voltage; at the same time, the optical fingerprint detection module can control the charge elimination circuit to provide a reverse bias voltage to the pixel and turn on the first switch. At this time, the optical fingerprint detection module works in a scanning state, and the pixel collects the light signal and converts it into an electrical signal and outputs it to the data reading circuit. The data reading circuit processes the electrical signal and outputs it to the analog-to-digital converter. The processor obtains digital data from the analog-to-digital converter to form fingerprint data. When the fingerprint data matches the preset template, the electronic device can be unlocked. Otherwise, the fingerprint detection is performed again until the unlocking is completed or the fingerprint detection is ended.

[0102] In other words, in this application scenario, when a finger touches the fingerprint detection area on the display screen, if the contact area is sufficient, the system will inform the optical fingerprint detection module to start preparing, and the charge clearing action can be performed at this time. The drive circuit in the optical fingerprint detection module can turn on the pixel, so that all photodiodes can work together to clear the charge and improve efficiency. Next, after the bias switch in the charge elimination voltage controls the bias power supply to provide a reverse bias voltage, the drive circuit scans normally, so that the entire optical fingerprint detection module is close to the actual operating condition, making the system more stable. At this time, the switch can be turned on or off, depending on whether it can be immediately stable when entering normal scanning (SW off). If instability occurs, then before entering normal scanning and acquisition, a charge clearing action must be performed to avoid excessive noise.

[0103] Fig.21 21 is a block diagram of an electronic device according to an exemplary embodiment. For example, the electronic device 2100 may be a smart phone, a computer, a digital broadcast terminal, a tablet device, a medical device, a fitness device, a personal digital assistant, etc.

[0104] Reference Fig.21 , the electronic device 2100 may include one or more of the following components: a processing component 2102, a memory 2104, a power component 2106, a multimedia component 2108, an audio component 2110, an input / output (I / O) interface 2112, a sensor component 2114, a communication component 2116, and an image acquisition component 2118.

[0105] The processing component 2102 generally controls the overall operation of the electronic device 2100, such as operations associated with display, phone calls, data communications, camera operations, and recording operations. The processing component 2102 may include one or more processors 2120 to execute computer programs. In addition, the processing component 2102 may include one or more modules to facilitate interaction between the processing component 2102 and other components. For example, the processing component 2102 may include a multimedia module to facilitate interaction between the multimedia component 2108 and the processing component 2102.

[0106] The memory 2104 is configured to store various types of data to support operations on the electronic device 2100. Examples of such data include computer programs for any application or method operating on the electronic device 2100, contact data, phone book data, messages, pictures, videos, etc. The memory 2104 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk or optical disk.

[0107] The power supply component 2106 provides power to various components of the electronic device 2100. The power supply component 2106 may include a power management system, one or more power supplies, and other components associated with generating, managing, and distributing power to the electronic device 2100. The power supply component 2106 may include a power supply chip, and the controller may communicate with the power supply chip to control the power supply chip to turn on or off the switch device, so that the battery supplies power to the mainboard circuit or not.

[0108] The multimedia component 2108 includes a screen that provides an output interface between the electronic device 2100 and the target object. In some embodiments, the screen may include a liquid crystal display (LCD) and a touch panel (TP). If the screen includes a touch panel, the screen may be implemented as a touch screen to receive input signals from the target object. The touch panel includes one or more touch sensors to sense touch, slide, and gestures on the touch panel. The touch sensor may not only sense the boundaries of a touch or slide action, but also detect the duration and pressure associated with the touch or slide operation.

[0109] The audio component 2110 is configured to output and / or input audio signals. For example, the audio component 2110 includes a microphone (MIC), and when the electronic device 2100 is in an operation mode, such as a call mode, a recording mode, and a voice recognition mode, the microphone is configured to receive an external audio signal. The received audio signal can be further stored in the memory 2104 or sent via the communication component 2116. In some embodiments, the audio component 2110 also includes a speaker for outputting audio signals.

[0110] The I / O interface 2112 provides an interface between the processing component 2102 and a peripheral interface module, which may be a keyboard, a click wheel, a button, etc.

[0111] The sensor component 2114 includes one or more sensors for providing various aspects of status assessment for the electronic device 2100. For example, the sensor component 2114 can detect the open / closed state of the electronic device 2100, the relative positioning of components, such as the display screen and keypad of the electronic device 2100, and the sensor component 2114 can also detect the position change of the electronic device 2100 or a component, the presence or absence of contact between the target object and the electronic device 2100, the orientation or acceleration / deceleration of the electronic device 2100, and the temperature change of the electronic device 2100. In this example, the sensor component 2114 may include a magnetic sensor, a gyroscope, and a magnetic field sensor, wherein the magnetic field sensor includes at least one of the following: a Hall sensor, a thin film magnetoresistive sensor, and a magnetic liquid acceleration sensor.

[0112] The communication component 2116 is configured to facilitate wired or wireless communication between the electronic device 2100 and other devices. The electronic device 2100 can access a wireless network based on a communication standard, such as WiFi, 2G, 3G, 4G, 5G, or a combination thereof. In an exemplary embodiment, the communication component 2116 receives a broadcast signal or broadcast-related information from an external broadcast management system via a broadcast channel. In an exemplary embodiment, the communication component 2116 also includes a near field communication (NFC) module to facilitate short-range communication. For example, the NFC module can be implemented based on radio frequency identification (RFID) technology, infrared data association (IrDA) technology, ultra-wideband (UWB) technology, Bluetooth (BT) technology and other technologies.

[0113] In an exemplary embodiment, the electronic device 2100 may be implemented by one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), controllers, microcontrollers, microprocessors, or other electronic components.

[0114] In an exemplary embodiment, a computer readable storage medium is also provided, such as a memory 2104 including instructions, and the above executable computer program can be executed by a processor. The readable storage medium can be a ROM, a random access memory (RAM), a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, etc.

[0115] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the disclosure disclosed herein. The present disclosure is intended to cover any variations, uses, or adaptations that follow the general principles of the present disclosure and include common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The description and examples are to be considered exemplary only, and the true scope and spirit of the present disclosure are indicated by the following claims.

[0116] It should be understood that the present disclosure is not limited to the exact structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. An electronic device, characterized in that: The optical fingerprint detection module comprises a display screen and an optical fingerprint detection module arranged below the display screen; the optical fingerprint detection module comprises a plurality of row control lines and a plurality of column data lines, a pixel is arranged at the intersection of any row control line and any column data line, a driving circuit connected to the plurality of row control lines and a power supply circuit for supplying power to the driving circuit; The power supply circuit is used to provide a first driving voltage to the driving circuit during a scanning phase, and the driving circuit is used to sequentially turn on each row of pixels during the scanning phase to collect light signals; The power supply circuit is used to provide a second driving voltage to the driving circuit in a reset phase, and the driving circuit is used to turn on each pixel in the reset phase to eliminate the charge in each pixel; The second driving voltage is greater than the first driving voltage; The optical fingerprint detection module further includes a data driving circuit; the data driving circuit includes a power supply and a bias switch, and the power supply is connected to each column data line respectively through the bias switch; The power supply is used to provide a reverse bias voltage and a forward bias voltage; the reverse bias voltage is a negative value, and the forward bias voltage is a positive value; The bias switch is used to provide a reverse bias voltage to the data line during a scan phase and to provide a forward bias voltage to the data line during a reset phase; Alternatively, the optical fingerprint detection module further includes a charge elimination circuit; the charge elimination circuit is used to provide a forward bias voltage to pixels in an on state during a reset phase to eliminate the charge in each pixel.

2. The electronic device according to claim 1, characterized in that: The power supply circuit comprises a power supply, a charge pump circuit and a voltage stabilizing circuit; the charge pump circuit is connected to the power supply and the voltage stabilizing circuit respectively; the power supply is used to provide a preset voltage; The charge pump circuit is used to boost the preset voltage to a third driving voltage; The voltage stabilizing circuit is used for converting the third driving voltage into the first driving voltage during the scanning phase and converting the third driving voltage into the second driving voltage during the resetting phase.

3. The electronic device according to claim 2, characterized in that: The voltage stabilizing circuit includes an operational amplifier, a transistor, a first resistor, a second resistor and a switch; the inverting input terminal of the operational amplifier receives a preset reference voltage, the non-inverting input terminal of the operational amplifier is connected to the first end of the second resistor, and the output terminal of the operational amplifier is respectively connected to the control electrode of the transistor and the first end of the switch; The second end of the switch is grounded; The first electrode of the transistor is connected to the output end of the charge pump circuit, and the second electrode of the transistor is connected to the first end of the first resistor and the output end of the voltage stabilizing circuit respectively; The first end of the second resistor is connected to the second end of the first resistor, and the second end of the second resistor is grounded.

4. The electronic device according to claim 1, characterized in that: The charge elimination circuit includes a bias switch and a bias power supply; the bias power supply is used to provide a forward bias voltage and a reverse bias voltage; wherein the forward bias voltage is used to make the photodiode in the pixel in a forward bias state, and the reverse bias voltage is used to make the photodiode in the pixel in a reverse bias state; The bias switch is used to provide a reverse bias voltage to the pixels in the on state during the scanning phase, and is used to provide a forward bias voltage to the pixels in the on state during the resetting phase.

5. The electronic device according to claim 4, characterized in that: The charge elimination circuit also includes a first switch and a preset power supply; the first end of the first switch is connected to the data line of the column, the second end of the first switch is connected to the preset power supply, and the control end of the first switch is connected to the drive circuit; the first switch is used to connect the data line of the column and the preset power supply when receiving a control signal from the drive circuit.

6. The electronic device according to claim 5, characterized in that: The preset power source includes at least one of the following: ground, a negative voltage source and a current source.

7. The electronic device according to claim 1, characterized in that: The driving circuit includes a first driving unit and a second driving unit; The first driving unit is used to output control signals to each row control line in sequence during the scanning phase; The second driving unit is used to output control signals to each group of control lines in sequence during the reset phase.

8. The electronic device according to claim 1, characterized in that: The optical fingerprint detection module further includes a data reading circuit, wherein the data reading circuit includes a plurality of data reading units, each of which is connected to a data line in a one-to-one correspondence; The data reading unit includes an operational amplifier and a feedback capacitor; the inverting input terminal of the operational amplifier is respectively connected to the positive terminal of the data line of the column and the first end of the feedback capacitor, the non-inverting input terminal of the operational amplifier is grounded, and the output terminal of the operational amplifier is connected to the second end of the feedback capacitor.

9. The electronic device according to claim 8, characterized in that: The data reading circuit further includes an analog-to-digital converter, which is connected to each data reading unit respectively and is used to perform analog-to-digital conversion on the pixel data output by each data reading unit.

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