A self-capacitance fingerprint detection circuit and method

Abstract

The application discloses a self-capacitance fingerprint detection circuit and method, comprising a target pixel, a fingerprint pixel, an adjacent pixel, a switch network, a local operational amplifier, a first voltage source and a second voltage source; the target pixel and the adjacent pixel are connected with the local operational amplifier through the switch network; the first voltage source is connected with the target pixel and the adjacent pixel through the switch network; the elimination of the parasitic effect and the detection of the fingerprint are realized through three steps of detection electrode initialization, parasitic electrode reset and transfer of finger charge; the parasitic effect between the target pixel detection electrode and the parasitic electrode is completely eliminated without charging and discharging the circuit outside the target pixel detection electrode, the fingerprint sensitivity is improved, the circuit is simplified, and the power consumption is saved.

Description

Technical Field

[0001] This invention relates to the field of capacitive fingerprint detection technology, and in particular to a self-capacitive fingerprint detection circuit and method. Background Technology

[0002] There are various methods of fingerprint acquisition, including optical fingerprint acquisition, capacitive fingerprint acquisition and ultrasonic fingerprint acquisition. Among them, capacitive fingerprint acquisition relies on capacitive fingerprint sensors to acquire fingerprint images. Due to their advantages such as small size, low power consumption and high sensitivity, capacitive fingerprint sensors are widely used in mobile phones, computers, door locks and other fields.

[0003] A typical capacitive fingerprint sensor usually consists of many fingerprint pixels arranged in a matrix. Each fingerprint pixel contains at least one detection electrode to sense the capacitance between the pixel and the finger, and also includes an isolation electrode to isolate the detection electrode. When the cover layer thickness on the fingerprint sensor reaches 100µm, the capacitance difference between the fingerprint ridges can be as small as 0.1fF, while the parasitic capacitance between the detection electrode and the isolation electrode can be as high as 50fF to 100fF. The parasitic capacitance between the detection electrode and adjacent pixels can also reach several fF or more. The presence of these parasitic capacitances significantly reduces the sensitivity and dynamic range of fingerprint signal detection.

[0004] To reduce the impact of these parasitic capacitances on signal acquisition, one approach is to transmit an electrical signal to the finger via a conductive metal ring around the fingerprint sensor and then couple it back to the detection electrode. This method increases the cost and complexity of the fingerprint detection system and reduces its reliability. Another approach is to add an additional driving circuit when the detection electrode is working, so that the potential of the isolation electrode and the surrounding adjacent pixels changes synchronously with the potential of the detected electrode. Although this method can compensate for most of the parasitic effects, the complexity of the circuit and the power consumption will increase significantly. Summary of the Invention

[0005] The purpose of this invention is to provide a self-capacitance fingerprint detection circuit and method, which eliminates parasitic capacitance, reduces power consumption in the circuit, and simplifies the circuit structure.

[0006] To solve the above technical problems, the present invention provides a self-capacitance fingerprint detection circuit, comprising: a target pixel, adjacent pixels, a switching network, a local operational amplifier, a first voltage source, and a second voltage source;

[0007] The target pixel includes a target pixel detection electrode and a target pixel isolation electrode; the adjacent pixel includes an adjacent pixel detection electrode and an adjacent pixel isolation electrode.

[0008] The target pixel and the adjacent pixels are connected to the local operational amplifier through the switching network. The local operational amplifier resets the parasitic electrode and transfers the charge stored in the capacitance between the target pixel detection electrode and the finger to the adjacent pixel detection electrode and the adjacent pixel isolation electrode. The second voltage source is connected to the positive input terminal of the local operational amplifier. The first voltage source is connected to the target pixel and the adjacent pixels through the switching network and initializes the target pixel detection electrode.

[0009] Furthermore, the local operational amplifier is connected to the target pixel detection electrode, the target pixel isolation electrode, the adjacent pixel detection electrode, and the adjacent pixel isolation electrode through the switching network;

[0010] The first voltage source is connected to the target pixel detection electrode, the target pixel isolation electrode, the adjacent pixel detection electrode, and the adjacent pixel isolation electrode through the switching network.

[0011] Furthermore, the negative input and output terminals of the local operational amplifier are connected through the switching network.

[0012] Furthermore, the switch network includes a first switch, a second switch, a third switch, a fourth switch, a fifth switch, a sixth switch, a seventh switch, an eighth switch, and a ninth switch;

[0013] The adjacent pixel detection electrode is connected to the negative input terminal of the local operational amplifier through a seventh switch and a second switch; the adjacent pixel detection electrode is connected to the first voltage source through a seventh switch and a third switch.

[0014] The adjacent pixel isolation electrode is connected to the negative input terminal of the local operational amplifier through the ninth switch and the second switch; the adjacent pixel isolation electrode is connected to the output terminal of the local operational amplifier through the fifth switch; the adjacent pixel isolation electrode is connected to the first voltage source through the ninth switch and the third switch.

[0015] The target pixel detection electrode is connected to the negative input terminal of the local operational amplifier through the sixth switch and the second switch; the target pixel detection electrode is connected to the first voltage source through the sixth switch and the third switch;

[0016] The target pixel isolation electrode is connected to the negative input terminal of the local operational amplifier via the eighth switch and the second switch; the target pixel isolation electrode is connected to the output terminal of the local operational amplifier via the fourth switch; the target pixel isolation electrode is connected to the first voltage source via the eighth switch and the third switch.

[0017] The negative input terminal and output terminal of the local operational amplifier are connected through the first switch.

[0018] The present invention also provides a method for detecting self-capacitance fingerprints, the method comprising the following steps:

[0019] Initialize the voltage of the target pixel detection electrode to the target potential set in the first voltage source;

[0020] Reset the parasitic electrode to the reference potential set in the second voltage source; and

[0021] The charge stored in the capacitance between the target pixel detection electrode and the finger is transferred to the adjacent pixel detection electrode and the adjacent pixel isolation electrode, and the magnitude of the charge is reflected in the output voltage of the local operational amplifier.

[0022] Furthermore, during the initialization of the detection electrode, the first, third, and sixth switches in the switch network are closed, while the second, fourth, fifth, seventh, eighth, and ninth switches are open.

[0023] Once the detection electrode is initialized, the third switch and the sixth switch are disconnected.

[0024] Furthermore, during the initialization of the detection electrode, the negative input and output terminals of the local operational amplifier are short-circuited; the first voltage source is connected to the target pixel detection electrode through a switching network; the first voltage source initializes the target pixel detection electrode to the target potential.

[0025] Furthermore, during the process of resetting the parasitic electrode, the first, second, fifth, seventh, and eighth switches in the switch network are closed, while the fourth, third, sixth, and ninth switches are open.

[0026] Furthermore, during the parasitic electrode reset process, the target pixel isolation electrode is connected to the negative input terminal of the local operational amplifier through a switching network, and the adjacent pixel detection electrode and the adjacent pixel isolation electrode are connected across the negative input terminal and the output terminal of the local operational amplifier through the switching network; the negative input terminal and the output terminal of the local operational amplifier are short-circuited; and the local operational amplifier resets the parasitic electrode connected to the negative input terminal and the output terminal.

[0027] Furthermore, during the transfer of charge on the finger, the second, fifth, sixth, seventh, and eighth switches in the switch network are closed, while the first, third, fourth, and ninth switches are open.

[0028] Furthermore, during the transfer of charge on the finger, the adjacent pixel detection electrode is connected to the negative input terminal of the local operational amplifier via a switching network; the adjacent pixel isolation electrode is connected to the output terminal of the local operational amplifier via a switching network; the target pixel detection electrode and the target pixel isolation electrode are connected to the negative input terminal of the local operational amplifier via a switching network; the negative input terminal and the output terminal of the local operational amplifier are disconnected; the charge stored in the capacitance between the target pixel detection electrode and the finger is transferred to the adjacent pixel detection electrode and the adjacent pixel isolation electrode, and the charge value is reflected in the output voltage of the local operational amplifier.

[0029] Furthermore, the charge stored on the capacitor between the target pixel detection electrode and the finger is (Vprg-Vref)*Cf, which generates a voltage change of (Vprg-Vref)*Cf / Cs2 at the output of the local operational amplifier.

[0030] Compared with the prior art, the present invention has at least the following beneficial effects:

[0031] This invention eliminates parasitic effects by short-circuiting the parasitic electrode and the target pixel detection electrode, eliminating the need for additional driving circuits, simplifying circuit complexity, and significantly saving power consumption. Furthermore, the method of short-circuiting the parasitic electrode and the target pixel detection electrode to eliminate parasitic effects provides more thorough compensation for parasitic charges. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the circuit structure of the self-capacitance fingerprint detection circuit in Embodiment 1 of the present invention;

[0033] Figure 2 This is a detailed circuit diagram of the self-capacitance fingerprint detection circuit in Embodiment 1 of the present invention;

[0034] Figure 3 This is a schematic diagram of the circuit connection for the detection electrode initialization process in Embodiment 2 of the present invention;

[0035] Figure 4 This is a schematic diagram of the circuit connection for the parasitic electrode reset process in Embodiment 2 of the present invention;

[0036] Figure 5 This is a schematic diagram of the circuit connection for the finger charge transfer process in Embodiment 2 of the present invention. Detailed Implementation

[0037] The following is a more detailed description of a self-capacitance fingerprint detection circuit and method according to the present invention, with reference to the schematic diagrams illustrating preferred embodiments of the invention. It should be understood that those skilled in the art can modify the invention described herein while still achieving its advantageous effects. Therefore, the following description should be understood as being of general knowledge to those skilled in the art and is not intended to limit the invention.

[0038] The invention is described more specifically by way of example in the following paragraphs with reference to the accompanying drawings. The advantages and features of the invention will become clearer from the following description and claims. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the invention.

[0039] Example 1

[0040] This embodiment provides a self-capacitance fingerprint detection circuit. Please refer to [reference needed]. Figure 1 It includes: target pixel, fingerprint pixel, adjacent pixel, switch network, local operational amplifier, first voltage source and second voltage source.

[0041] Specifically, the target pixel includes a target pixel detection electrode and a target pixel isolation electrode, and the adjacent pixels include adjacent pixel detection electrodes and adjacent pixel isolation electrodes. The target pixel and the adjacent pixels are connected to the local operational amplifier through the switching network. The local operational amplifier resets the parasitic electrode and transfers the charge stored in the capacitance between the target pixel detection electrode and the finger to the adjacent pixel detection electrode and the adjacent pixel isolation electrode. The second voltage source is connected to the positive input terminal of the local operational amplifier. The first voltage source is connected to the target pixel and the adjacent pixels through the switching network, and the first voltage source initializes the target pixel detection electrode.

[0042] Furthermore, the local operational amplifier is connected to the target pixel detection electrode, the target pixel isolation electrode, the adjacent pixel detection electrode, and the adjacent pixel isolation electrode through the switching network. The first voltage source is connected to the target pixel detection electrode, the target pixel isolation electrode, the adjacent pixel detection electrode, and the adjacent pixel isolation electrode through the switching network.

[0043] The first voltage source can initialize the target pixel detection electrode to the target voltage through a switching network.

[0044] In this embodiment, please refer to Figure 2 The switch network includes a first switch, a second switch, a third switch, a fourth switch, a fifth switch, a sixth switch, a seventh switch, an eighth switch, and a ninth switch.

[0045] Specifically, the adjacent pixel detection electrode is connected to the negative input terminal of the local operational amplifier via a seventh switch and a second switch; the adjacent pixel detection electrode is connected to the first voltage source via a seventh switch and a third switch. The adjacent pixel isolation electrode is connected to the negative input terminal of the local operational amplifier via a ninth switch and a second switch; the adjacent pixel isolation electrode is connected to the output terminal of the local operational amplifier via a fifth switch; the adjacent pixel isolation electrode is connected to the first voltage source via a ninth switch and a third switch. The target pixel detection electrode is connected to the negative input terminal of the local operational amplifier via a sixth switch and a second switch; the target pixel detection electrode is connected to the first voltage source via a sixth switch and a third switch. The target pixel isolation electrode is connected to the negative input terminal of the local operational amplifier via an eighth switch and a second switch; the target pixel isolation electrode is connected to the output terminal of the local operational amplifier via a fourth switch; the target pixel isolation electrode is connected to the first voltage source via an eighth switch and a third switch; the positive input terminal of the local operational amplifier is connected to the second voltage source; the negative input terminal and the output terminal of the local operational amplifier are connected via the first switch.

[0046] In one specific embodiment, the negative input terminal and the output terminal of the local operational amplifier are shorted by the first switch, so that the switching network operates in single-gain mode, in preparation for the reset of the target pixel detection electrode and the reset of the parasitic capacitance.

[0047] The self-capacitance fingerprint detection circuit in this embodiment has a simple structure, requiring only a local operational amplifier, a switching network, and a voltage source to complete its construction. Furthermore, the self-capacitance fingerprint detection circuit can completely eliminate the parasitic effect between the target pixel detection electrode and the parasitic electrode, thereby improving fingerprint sensitivity.

[0048] Example 2

[0049] This embodiment provides a self-capacitance fingerprint detection method, which uses the self-capacitance fingerprint detection circuit in Embodiment 1. The self-capacitance fingerprint detection method includes three steps: detection electrode initialization, parasitic electrode reset, and finger charge transfer.

[0050] Step 1 is to initialize the detection electrode, that is, to initialize the voltage of the target pixel detection electrode to the target potential set in the first voltage source;

[0051] The first voltage source can be set to output different target potentials as needed. In one specific embodiment, the target potential can be 7V.

[0052] For details, please refer to Figure 3In order to initialize the target pixel detection electrode to the target voltage, the first, third, and sixth switches in the switch network are closed, and the second, fourth, fifth, seventh, eighth, and ninth switches are open; after the detection electrode initialization is completed, the third and sixth switches are opened.

[0053] At this time, the negative input and output terminals of the local operational amplifier are shorted; the first voltage source is connected to the target pixel detection electrode through a switching network; the first voltage source initializes the target pixel detection electrode to the target potential. After the detection electrode is initialized, the amount of charge stored in the capacitor Cf between the target pixel detection electrode and the finger is Vprg*Cf.

[0054] Preferably, during the initialization of the detection electrode, the target pixel isolation electrode, the adjacent pixel detection electrode, and the adjacent pixel detection electrode can be in a floating state or clamped to any voltage.

[0055] Therefore, it can be seen that step one initializes the target pixel detection electrode by using the first voltage source. This process is simple, reduces system cost, and prepares for the subsequent charge transfer process.

[0056] Step two is to reset the parasitic electrode, that is, to reset the parasitic electrode to the reference potential set in the second voltage source.

[0057] For details, please refer to Figure 4 When the parasitic electrode needs to be reset, the first, second, fifth, seventh, and eighth switches in the switching network are closed, while the fourth, third, sixth, and ninth switches are open.

[0058] At this time, the local operational amplifier operates in buffer mode, meaning the target pixel isolation electrode is connected to the negative input terminal of the local operational amplifier through the switching network, and the adjacent pixel detection electrode and the adjacent pixel isolation electrode are connected across the negative input terminal and the output terminal of the local operational amplifier through the switching network; the negative input terminal and the output terminal of the local operational amplifier are short-circuited. The local operational amplifier operating in buffer mode resets the parasitic electrodes to the voltage value of the second voltage source.

[0059] Specifically, the parasitic electrode includes the target pixel isolation electrode, the parasitic electrode of the adjacent pixel, and the adjacent pixel isolation electrode.

[0060] Furthermore, those skilled in the art will readily understand that, since the target detection electrode is in a floating state after the sixth switch is turned off, the charge on the target detection electrode will not decrease.

[0061] Step three involves the transfer of charge from the finger, specifically the transfer of charge stored in the capacitance between the target pixel detection electrode and the finger to the adjacent pixel detection electrode and the adjacent pixel isolation electrode. The magnitude of this charge is reflected in the output voltage of the local operational amplifier.

[0062] For details, please refer to Figure 5 When it is necessary to transfer the charge from the finger, the second, fifth, sixth, seventh, and eighth switches are closed, while the first, third, fourth, and ninth switches are open.

[0063] In this embodiment, the adjacent pixel detection electrode is connected to the negative input terminal of the local operational amplifier through the switch network; the adjacent pixel isolation electrode is connected to the output terminal of the local operational amplifier through the switch network; the target pixel detection electrode and the target pixel isolation electrode are connected to the negative input terminal of the local operational amplifier through the switch network; the negative input terminal and the output terminal of the local operational amplifier are disconnected.

[0064] Preferably, when transferring finger charge, the detection electrode and isolation electrode of the adjacent fingerprint pixel can be connected to the negative input terminal and the output terminal of the local operational amplifier respectively, or the detection electrode and isolation electrode of the adjacent fingerprint pixel can be connected to the output terminal and the negative input terminal of the local operational amplifier respectively.

[0065] At this time, the local operational amplifier operates in charge amplifier mode, using the parasitic capacitance between the adjacent pixel detection electrode and the adjacent pixel isolation electrode as the feedback capacitor; the charge on the capacitor between the target pixel detection electrode and the finger will be transferred to the feedback capacitor, and the charge value will be reflected in the output voltage of the local operational amplifier.

[0066] It is understandable that when the first switch is disconnected and the sixth switch is closed, the positive and negative charges sensed by the target pixel detection electrode due to the parasitic capacitance will be completely canceled out because the target pixel detection electrode, the target pixel isolation electrode, and the adjacent pixel detection electrode are short-circuited. Therefore, the parasitic effect between the target pixel detection electrode and the parasitic electrode is completely eliminated.

[0067] Once the circuit stabilizes, that is, when there is no longer any stored charge transferred to the output of the local operational amplifier on the target pixel detection electrode, the amount of charge transferred to the feedback capacitor is (Vprg-Vref)*Cf, and a voltage change of (Vprg-Vref)*Cf / Cs2 is generated at the output of the local operational amplifier. The magnitude of the voltage change at the output of the local operational amplifier indirectly reflects the size of the detection capacitor, and this change is linear.

[0068] Therefore, it can be seen that the method of short-circuiting the target pixel detection electrode, the target pixel isolation electrode and the adjacent pixel detection electrode in step three to eliminate the parasitic effect not only makes the compensation for parasitic charge more thorough, but also simplifies the circuit complexity and greatly saves power consumption.

[0069] In summary, this invention no longer uses external electrodes similar to metal rings to drive the finger. Instead, it first initializes the voltage of the target pixel detection electrode and then performs charge transfer to drive the finger, reducing system cost and improving reliability. Furthermore, this embodiment no longer uses the method of synchronous charging and discharging of parasitic electrodes to eliminate parasitic effects. Instead, it uses a method of short-circuiting the parasitic electrode and the target pixel detection electrode to eliminate parasitic effects. This not only provides more thorough compensation for parasitic charges but also simplifies circuit complexity and greatly saves power consumption.

[0070] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A self-capacitance fingerprint detection circuit, characterized by, include: Target pixel, adjacent pixels, switch network, local operational amplifier, first voltage source and second voltage source; The target pixel includes a target pixel detection electrode and a target pixel isolation electrode; the adjacent pixel includes an adjacent pixel detection electrode and an adjacent pixel isolation electrode. The target pixel and the adjacent pixels are connected to the local operational amplifier through the switching network. The local operational amplifier resets the parasitic electrode and transfers the charge stored in the capacitor between the target pixel detection electrode and the finger to the adjacent pixel detection electrode and the adjacent pixel isolation electrode. The second voltage source is connected to the positive input terminal of the local operational amplifier. The first voltage source is connected to the target pixel and the adjacent pixels through the switching network, and the first voltage source initializes the detection electrode of the target pixel; The switch network includes a first switch, a second switch, a third switch, a fourth switch, a fifth switch, a sixth switch, a seventh switch, an eighth switch, and a ninth switch; The adjacent pixel detection electrode is connected to the negative input terminal of the local operational amplifier through a seventh switch and a second switch; the adjacent pixel detection electrode is connected to the first voltage source through a seventh switch and a third switch. The adjacent pixel isolation electrode is connected to the negative input terminal of the local operational amplifier through the ninth switch and the second switch; the adjacent pixel isolation electrode is connected to the output terminal of the local operational amplifier through the fifth switch; The adjacent pixel isolation electrode is connected to the first voltage source through the ninth switch and the third switch; The target pixel detection electrode is connected to the negative input terminal of the local operational amplifier through the sixth switch and the second switch; the target pixel detection electrode is connected to the first voltage source through the sixth switch and the third switch. The target pixel isolation electrode is connected to the negative input terminal of the local operational amplifier via the eighth switch and the second switch; the target pixel isolation electrode is connected to the output terminal of the local operational amplifier via the fourth switch; the target pixel isolation electrode is connected to the first voltage source via the eighth switch and the third switch. The negative input terminal and output terminal of the local operational amplifier are connected through the first switch.

2. The self-capacitance fingerprint detection circuit as described in claim 1, characterized in that, The local operational amplifier is connected to the target pixel detection electrode, the target pixel isolation electrode, the adjacent pixel detection electrode, and the adjacent pixel isolation electrode through the switching network; The first voltage source is connected to the target pixel detection electrode, the target pixel isolation electrode, the adjacent pixel detection electrode, and the adjacent pixel isolation electrode through the switching network.

3. The self-capacitance fingerprint detection circuit as described in claim 1, characterized in that, The negative input and output terminals of the local operational amplifier are connected through the switching network.

4. A self-capacitance fingerprint detection method, characterized by, The self-capacitance fingerprint detection method includes the following steps: Initialize the voltage of the target pixel detection electrode to the target potential set in the first voltage source; Reset the parasitic electrode to the reference potential set in the second voltage source; and, The charge stored in the capacitor between the target pixel detection electrode and the finger is transferred to the adjacent pixel detection electrode and the adjacent pixel isolation electrode, and the magnitude of the charge is reflected in the output voltage of the local operational amplifier. During the transfer of charge on the finger, the adjacent pixel detection electrode is connected to the negative input terminal of the local operational amplifier through a switching network; the adjacent pixel isolation electrode is connected to the output terminal of the local operational amplifier through the switching network; the target pixel detection electrode and the target pixel isolation electrode are connected to the negative input terminal of the local operational amplifier through the switching network; the negative input terminal and the output terminal of the local operational amplifier are disconnected; the charge stored in the capacitance between the target pixel detection electrode and the finger is transferred to the adjacent pixel detection electrode and the adjacent pixel isolation electrode, and the magnitude of the charge is reflected in the output voltage of the local operational amplifier; The charge stored on the capacitor between the target pixel detection electrode and the finger is (Vprg-Vref)×Cf, which generates a voltage change of (Vprg-Vref)×Cf / Cs2 at the output of the local operational amplifier. The switch network includes a first switch, a second switch, a third switch, a fourth switch, a fifth switch, a sixth switch, a seventh switch, an eighth switch, and a ninth switch. The adjacent pixel detection electrode is connected to the negative input terminal of the local operational amplifier through the seventh switch and the second switch; the adjacent pixel detection electrode is connected to the first voltage source through the seventh switch and the third switch; The adjacent pixel isolation electrode is connected to the negative input terminal of the local operational amplifier through the ninth switch and the second switch; the adjacent pixel isolation electrode is connected to the output terminal of the local operational amplifier through the fifth switch; The adjacent pixel isolation electrode is connected to the first voltage source through the ninth switch and the third switch; The target pixel detection electrode is connected to the negative input terminal of the local operational amplifier through the sixth switch and the second switch; the target pixel detection electrode is connected to the first voltage source through the sixth switch and the third switch. The target pixel isolation electrode is connected to the negative input terminal of the local operational amplifier via the eighth switch and the second switch; the target pixel isolation electrode is connected to the output terminal of the local operational amplifier via the fourth switch; the target pixel isolation electrode is connected to the first voltage source via the eighth switch and the third switch. The negative input terminal and output terminal of the local operational amplifier are connected through the first switch.

5. The self-capacitance fingerprint detection method as described in claim 4, characterized in that, During the initialization of the detection electrode, the first, third, and sixth switches in the switch network are closed. The second, fourth, fifth, seventh, eighth, and ninth switches are off; Once the detection electrode is initialized, the third switch and the sixth switch are disconnected.

6. The self-capacitance fingerprint detection method as described in claim 4, characterized in that, During the initialization of the detection electrode, the negative input and output terminals of the local operational amplifier are shorted. The first voltage source is connected to the target pixel detection electrode via a switching network; The first voltage source initializes the target pixel detection electrode to the target potential.

7. The self-capacitance fingerprint detection method as described in claim 4, characterized in that, During the process of resetting the parasitic electrode, the first, second, fifth, seventh, and eighth switches in the switch network are closed, while the fourth, third, sixth, and ninth switches are open.

8. The self-capacitance fingerprint detection method as described in claim 4, characterized in that, During the parasitic electrode reset process, the target pixel isolation electrode is connected to the negative input terminal of the local operational amplifier through a switching network, and the adjacent pixel detection electrode and the adjacent pixel isolation electrode are connected across the negative input terminal and the output terminal of the local operational amplifier through the switching network; the negative input terminal and the output terminal of the local operational amplifier are short-circuited; the local operational amplifier resets the parasitic electrode connected to the negative input terminal and the output terminal.

9. The self-capacitance fingerprint detection method as described in claim 4, characterized in that, During the transfer of charge on the finger, the second, fifth, sixth, seventh, and eighth switches in the switch network are closed, while the first, third, fourth, and ninth switches are open.

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