Fingerprint sensing chip, capacitive fingerprint module and fingerprint image acquisition method

Abstract

The embodiment of the invention discloses a fingerprint sensing chip, a capacitive fingerprint module and a fingerprint image acquisition method, the fingerprint sensing chip comprises a pixel array, the pixel array comprises M * N pixel units, M is the row number of the pixel units, and N is the column number of the pixel units; each pixel unit comprises a pixel electrode, a first switch corresponding to the pixel electrode, a storage capacitor and a second switch corresponding to the storage capacitor, the pixel electrode is electrically connected with the driving module through the first switch, and the pixel electrode is electrically connected with the storage capacitor through the second switch; the storage capacitor is used for storing charges generated by the pixel electrode. The capacitive fingerprint module comprises a fingerprint sensing chip, a driving module and a measuring module, the driving module is used for outputting a driving signal to each pixel electrode, and the measuring module is used for converting charges into a digital signal for representing a pixel value; the pixel array of the fingerprint sensing chip is electrically connected with the driving module, and the pixel array of the fingerprint sensing chip is electrically connected with the measuring module.

Description

Technical Field

[0001] This application relates to the field of biometric technologies, and particularly to a fingerprint sensing chip, a capacitive fingerprint module, and a fingerprint image acquisition method. Background Art

[0002] With the rapid development of biometric technologies, biometric technologies are widely applied to electronic devices. For example, device unlocking, mobile payment, etc. As one of the most widely used and mature technologies in biometric technologies, fingerprint recognition technology mainly analyzes global and local features of fingerprints, such as fingerprint ridges, fingerprint valleys, fingerprint endpoints, fingerprint bifurcation points, or fingerprint divergence points, and then confirms the user's identity through comparison.

[0003] Currently, capacitive technology is the most commonly used technology for fingerprint acquisition. Electronic devices use capacitive fingerprint modules. Its basic principle is that the finger surface serves as one electrode of a capacitor, forming a capacitive matrix with the sensing electrode array on the capacitive fingerprint module. The capacitances formed by fingerprint valleys and fingerprint ridges with the sensing electrodes on the capacitive fingerprint module are different, and the stored charges are different. Therefore, by measuring the charge magnitude, the shapes of fingerprint valleys and fingerprint ridges can be distinguished, thereby obtaining complete fingerprint information. However, in related technologies, the image acquisition time of capacitive fingerprint modules is relatively long, resulting in relatively long fingerprint recognition time. Summary of the Invention

[0004] Embodiments of this application provide a fingerprint sensing chip, a capacitive fingerprint module, and a fingerprint image acquisition method, which can shorten the image acquisition duration of the capacitive fingerprint module, thereby shortening the fingerprint recognition time.

[0005] According to the first aspect of this application, a fingerprint sensing chip is disclosed, including a pixel array, where the pixel array includes: M*N pixel units, M is the number of rows of pixel units in the pixel array, N is the number of columns of pixel units in the pixel array, and both M and N are integers greater than 1;

[0006] Each pixel unit includes: a pixel electrode, a first switch corresponding to the pixel electrode, a storage capacitor, and a second switch corresponding to the storage capacitor. The pixel electrode is electrically connected to a driving module through the first switch, the pixel electrode is electrically connected to the storage capacitor through the second switch, and the storage capacitor is used to store the charge generated by the pixel electrode.

[0007] According to the second aspect of this application, a capacitive fingerprint module is disclosed, including the fingerprint sensing chip as in the first aspect, and further including a driving module and a measuring module;

[0008] The driving module is configured to output a driving signal to each pixel electrode, and the measuring module is configured to convert the charge into a digital signal for characterizing a pixel value;

[0009] The pixel array of the fingerprint sensing chip is electrically connected to the driving module, and the pixel array of the fingerprint sensing chip is electrically connected to the measuring module.

[0010] According to a third aspect of the present application, a fingerprint image acquisition method is disclosed, which is used to acquire a fingerprint image based on the capacitive fingerprint module in the second aspect. The method includes:

[0011] Control each first switch in the capacitive fingerprint module to switch to the conducting state, output a driving signal from the driving module to each pixel electrode of the pixel array, and after the driving signal output duration reaches a first duration, control each of the first switches to switch to the off state and stop outputting the driving signal;

[0012] Control each second switch in the capacitive fingerprint module to switch to the conducting state, and after the conducting state of the second switch is maintained for a second duration, control each of the second switches to switch to the off state; repeat all the above steps K times, where K is an integer greater than 2;

[0013] Control the measuring module of the capacitive fingerprint module to convert the charge output by the pixel array into a digital signal for characterizing the pixel value, and obtain a fingerprint image.

[0014] According to a fourth aspect of the present application, an electronic device is disclosed, including: the capacitive fingerprint module as in the second aspect, a memory, a processor, and a computer program stored on the memory, and the processor executes the computer program to implement the fingerprint image acquisition method as in the third aspect.

[0015] According to a fifth aspect of the present application, a computer-readable storage medium is disclosed, on which a computer program / instructions are stored, and when the computer program / instructions are executed by a processor, the fingerprint image acquisition method as in the third aspect is implemented.

[0016] According to a sixth aspect of the present application, a computer program product is disclosed, including computer program / instructions, and when the computer program / instructions are executed by a processor, the fingerprint image acquisition method as in the third aspect is implemented.

[0017] In the embodiment of the present application, the capacitive fingerprint module includes: a fingerprint sensing chip, a driving module, and a measuring module; the fingerprint sensing chip includes a pixel array, and the pixel array includes: M*N pixel units, where M is the number of rows of pixel units in the pixel array, and N is the number of columns of pixel units in the pixel array. Each pixel unit includes: a pixel electrode, a first switch corresponding to the pixel electrode, a storage capacitor, and a second switch corresponding to the storage capacitor. The pixel electrode is electrically connected to the driving module through the first switch, and the pixel electrode is electrically connected to the storage capacitor through the second switch. The storage capacitor is used to store the charge generated by the pixel electrode; the driving module is used to output a driving signal to each pixel electrode, and the measuring module is used to convert the charge into a digital signal for characterizing the pixel value; there is an electrical connection between the pixel array of the fingerprint sensing chip and the driving module, and there is an electrical connection between the pixel array of the fingerprint sensing chip and the measuring module.

[0018] In the embodiment of the present application, when collecting a fingerprint image based on the above capacitive fingerprint module, control each first switch in the capacitive fingerprint module to switch to the conducting state, output a driving signal to each pixel electrode of the pixel array through the driving module. After the output duration of the driving signal reaches the first duration, control each first switch to switch to the off state and stop outputting the driving signal; control each second switch in the capacitive fingerprint module to switch to the conducting state. After the conducting state of the second switch is maintained for the second duration, control each second switch to switch to the off state; repeat all the above steps K times, where K is an integer greater than 2; control the measuring module of the capacitive fingerprint module to convert the charge output by the pixel array into a digital signal for characterizing the pixel value, and obtain the fingerprint image.

[0019] It can be seen that in the embodiment of the present application, since each pixel unit of the capacitive fingerprint module includes, in addition to a pixel electrode and a first switch corresponding to the pixel electrode, a storage capacitor and a second switch corresponding to the storage capacitor, when collecting a fingerprint image based on the capacitive fingerprint module, it is possible to realize parallel charging, acquisition, and storage of charges for the pixel electrodes of all pixel units of the capacitive fingerprint module. On the one hand, the image acquisition duration of the capacitive fingerprint module is shortened, thereby shortening the fingerprint recognition time; on the other hand, the edge electric field of the pixel electrode is better during parallel charging, and finally, the charge of the pixel electrode will be more, the pixel value of each pixel unit obtained is larger, and the fingerprint image is clearer. Description of the Drawings

[0020] Figure 1 is the circuit diagram of the pixel array of the fingerprint sensing chip in the related art;

[0021] Figure 2 is one of the circuit diagrams of the pixel array of the fingerprint sensing chip provided by the embodiment of the present application;

[0022] Figure 3It is the second circuit diagram of the pixel array of a fingerprint sensing chip provided by an embodiment of the present application;

[0023] Figure 4 It is the third circuit diagram of the pixel array of a fingerprint sensing chip provided by an embodiment of the present application;

[0024] Figure 5 It is the fourth circuit diagram of the pixel array of a fingerprint sensing chip provided by an embodiment of the present application;

[0025] Figure 6 It is the first structural schematic diagram of a capacitive fingerprint module provided by an embodiment of the present application;

[0026] Figure 7 It is the second structural schematic diagram of a capacitive fingerprint module provided by an embodiment of the present application;

[0027] Figure 8 It is the flowchart of a fingerprint image acquisition method provided by an embodiment of the present application;

[0028] Figure 9 It is the structural schematic diagram of a fingerprint image acquisition device provided by an embodiment of the present application;

[0029] Figure 10 It is the structural block diagram of an electronic device provided by an embodiment of the present application. Detailed implementation manners

[0030] To make the above objects, features, and advantages of the present application more obvious and understandable, the present application will be further described in detail below with reference to the accompanying drawings and specific implementation manners.

[0031] It should be noted that for method embodiments, for simplicity of description, they are all expressed as a series of action combinations. However, those skilled in the art should know that the embodiments of the present application are not limited by the described action sequences, because according to the embodiments of the present application, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions involved are not necessarily essential to the embodiments of the present application.

[0032] Biometric technologies have been widely applied to various terminal devices or electronic devices. Biometric identification technologies include, but are not limited to, fingerprint recognition, palmprint recognition, vein recognition, iris recognition, face recognition, liveness recognition, anti-counterfeiting recognition, etc. Among them, fingerprint recognition usually includes optical fingerprint recognition, capacitive fingerprint recognition, and ultrasonic fingerprint recognition. With the rise of full-screen technology, the fingerprint recognition module can be set in a partial area or the entire area under the display screen, thus forming an under-display optical fingerprint recognition; or, part or all of the optical fingerprint recognition module can be integrated into the display screen of the electronic device, thus forming an in-display optical fingerprint recognition. The display screen can be an organic light-emitting diode (OLED) display screen or a liquid crystal display (LCD) screen, etc. The fingerprint recognition method usually includes steps such as fingerprint image acquisition, preprocessing, feature extraction, and feature matching. Some or all of the above steps can be implemented by traditional computer vision (CV) algorithms or by deep learning algorithms based on artificial intelligence (AI). Fingerprint recognition technology can be applied to portable or mobile terminals such as smart phones, tablets, and gaming devices, as well as other electronic devices such as smart door locks, cars, and bank ATMs for fingerprint unlocking, fingerprint payment, fingerprint attendance, identity authentication, etc.

[0033] For ease of understanding, some related concepts and application scenarios involved in the embodiments of the present application will be introduced first below.

[0034] I. Related Concepts

[0035] A MOS transistor is a semiconductor device. MOS transistors can be divided into two types: N-type MOS (NMOS) transistors and P-type MOS (PMOS) transistors. For an NMOS transistor, it conducts when the input signal is high and cuts off when the input signal is low; for a PMOS transistor, it cuts off when the input signal is high and conducts when the input signal is low. In actual applications, any of the above types of MOS transistors can be used as the switch of the pixel array in the fingerprint sensing chip.

[0036] A capacitor is an electronic device that stores electrical energy in an electric field by accumulating charges on two closely spaced surfaces that are insulated from each other.

[0037] An operational amplifier is an electronic device that converts charge into a voltage value.

[0038] An analog-to-digital converter is an electronic device that converts analog signals into digital signals.

[0039] II. Application Scenarios

[0040] Currently, during the unlocking process of an electronic device through a capacitive fingerprint module, the main process is finger touch detection, fingerprint image acquisition, fingerprint recognition, and unlocking. In related technologies, the capacitive fingerprint module includes: a fingerprint sensing chip, a driving module, and a measuring module. The fingerprint sensing chip includes a pixel array, and the pixel array includes: M*N pixel units, N storage capacitors, and N switches corresponding to the N storage capacitors respectively. For example, Figure 1 as shown, taking the pixel unit 11 in the first row and first column of the pixel array as an example, the pixel unit 11 includes: a pixel electrode 111 and a corresponding switch 110. The pixel electrode 111 is electrically connected to the driving module through the switch 110. When the user's finger presses or touches above the pixel electrode 111, a pixel capacitor is formed between the pixel electrode 111 and the finger, and then charges are generated. Other pixel units in the pixel array are similar to the pixel unit 11 and will not be elaborated here.

[0041] The Cth row is the storage capacitor, and the capacitance of the storage capacitor is very large and can store a lot of charges. Taking c1 in the first column of the Cth row as an example, it includes: a storage capacitor c10 and a corresponding switch c11.

[0042] The upper ends of the "vertical lines" in each column of the pixel array are used to be electrically connected to the driving module. The driving module outputs a driving signal to the pixel electrodes in each column. Each "small black dot" in the pixel array represents an electrical connection. The measuring module is electrically connected to the storage capacitor, and each storage capacitor is connected to a measuring module. The measuring module is used to convert the charges in the storage capacitor into a digital signal for characterizing the pixel value.

[0043] In related technologies, the working process of the capacitive fingerprint module is as follows:

[0044] Step 1: Starting from the first row of the pixel array, switch the switches of the pixel units in the first row and the x rows below the first row to the conducting state. The driving module connected to the pixel units in each column provides a driving signal for the pixel electrodes in each column. After the switches are switched to the conducting state, the pixel capacitors in the first row and the x rows below the first row are charged. Then, switch the switches of the first row and the x rows below the first row to the off state, and control the driving module to stop inputting the driving signal, so that the charges are stored in the pixel capacitors, where x is an integer greater than or equal to 1;

[0045] Step 2: Switch the switches of the first row and the C-th row to the conducting state, transfer the charges of the pixel capacitors of each pixel unit in the first row to the storage capacitors in the C-th row, and discharge and empty the charges of the pixel capacitors in other rows. This process completes one charge acquisition for each pixel unit in the first row.

[0046] Step 3: Considering that the charge collected in a single acquisition is relatively small and multiple charge acquisitions are required, after K charge acquisitions are performed on the first row, the storage capacitors in the C-th row store the charges collected in K charge acquisitions. The charges in the storage capacitors in the C-th row are converted into digital signals through the measurement module to obtain the pixel values corresponding to each pixel unit in the first row.

[0047] Step 4: Repeat the above steps M times to collect the pixel values from the first row to the M-th row, completing the acquisition of a fingerprint image.

[0048] It should be noted that each time charge acquisition is performed on the pixel units in the i-th row (i≥2), switch the switches of the i-th row and the x rows of pixel units above and below the i-th row to the conducting state. The driving module connected to each column of pixel units provides a driving signal for the pixel electrodes of each column of pixel units. After the switches are switched to the conducting state, the pixel capacitors of the i-th row and the x rows of pixel units above and below the i-th row are charged. Then, switch the switches of the i-th row and the x rows of pixel units above and below the i-th row to the off state, and control the driving module to stop inputting the driving signal so that the charges are stored in the corresponding pixel capacitors; among them, for those with less than x rows on the upper and lower sides, open as many rows as there are.

[0049] Considering that the image acquisition duration of the capacitive fingerprint module consists of two parts: charge acquisition duration and charge measurement duration. Since the charge measurement duration is usually relatively short compared to the charge acquisition duration, the charge acquisition duration is the main factor affecting the fingerprint image acquisition duration. In the embodiments of the present application, the fingerprint sensing chip of the capacitive fingerprint module is mainly improved from the aspect of the charge acquisition duration.

[0050] From Figure 1 it can be seen that since all pixel units in the same column of the pixel array of the fingerprint sensing chip share a storage capacitor, it is necessary to serially acquire charges row by row. The charge acquisition duration of the pixel array is relatively long, resulting in a relatively long overall image acquisition duration, and further resulting in a relatively long fingerprint recognition time. To solve the above technical problems, the embodiments of the present application provide a fingerprint sensing chip, a capacitive fingerprint module, and a fingerprint image acquisition method.

[0051] Next, in combination with the accompanying drawings, a fingerprint sensing chip provided by the embodiments of the present application will be introduced.

[0052] In some embodiments provided by the present application, the fingerprint sensing chip includes a pixel array, and the pixel array includes: M*N pixel units, where M is the number of rows of pixel units in the pixel array, N is the number of columns of pixel units in the pixel array, and both M and N are integers greater than 1; each pixel unit includes: a pixel electrode, a first switch corresponding to the pixel electrode, a storage capacitor, and a second switch corresponding to the storage capacitor. The pixel electrode is electrically connected to the driving module through the first switch, and the pixel electrode is electrically connected to the storage capacitor through the second switch. The storage capacitor is used to store the charge generated by the pixel electrode.

[0053] Exemplarily, as Figure 2 shown, each "small black dot" in the pixel array of the fingerprint sensing chip represents an electrical connection; the "vertical line" 1 in the pixel array represents the first column, the "vertical line" 2 in the pixel array represents the second column,..., the "vertical line" N in the pixel array represents the Nth column, the "horizontal lines" 1a and 1b in the pixel array represent the first row, the "horizontal lines" 2a and 2b in the pixel array represent the second row,..., the "horizontal lines" Ma and Mb in the pixel array represent the Mth row. Taking the pixel unit P11 in the first row and the first column of the pixel array as an example, the pixel unit P11 includes: a pixel electrode S11, a first switch K11 corresponding to the pixel electrode S11, a storage capacitor S12, and a second switch K12 corresponding to the storage capacitor S12. When the user's finger presses or touches above the pixel electrode S11, a pixel capacitor is formed between the pixel electrode S11 and the finger, and then charge is generated. Other pixel units in the pixel array are similar to the pixel unit P11 and will not be elaborated here.

[0054] In the embodiments of the present application, the driving module can provide a driving signal for the pixel electrodes in each row of pixel units in the pixel array, that is, "row driving"; or the driving module can provide a driving signal for the pixel electrodes in each column of pixel units in the pixel array, that is, "column driving".

[0055] Exemplarily, in the row driving scenario, the left end of each row of "horizontal lines" named "a" in the pixel array is electrically connected to the driving module, and the driving module provides a driving signal for the pixel electrodes of the pixel units on each row.

[0056] Exemplarily, in the column driving scenario, the upper end of each column of "vertical lines" in the pixel array is electrically connected to the driving module, and the driving module provides a driving signal for the pixel electrodes of the pixel units on each column.

[0057] Different from the related art where all pixel units in the same column of the pixel array share a storage capacitor and need to serially charge and collect charges in sequence according to the number of rows, from Figure 2As can be seen, in the embodiments of the present application, each pixel unit in the pixel array has a storage capacitor, that is, each pixel unit exclusively has a storage capacitor. Therefore, parallel charging can be used to collect charges, shortening the charge collection time of the pixel array, thereby shortening the entire image acquisition time, and further shortening the fingerprint recognition time. In addition, when charging in parallel, the edge electric field of the pixel electrode is better, and finally, there will be more charges on the pixel electrode, the pixel values of each pixel unit obtained will be larger, and the fingerprint image will be clearer.

[0058] In some embodiments provided by the present application, based on Figure 2 the embodiments shown, each pixel unit may further include: a test capacitor and a third switch corresponding to the test capacitor; the storage capacitor is electrically connected to the test capacitor through the third switch.

[0059] Exemplarily, as Figure 3 shown, still taking the pixel unit P11 in the first row and the first column of the pixel array as an example, in addition to including: a pixel electrode S11, a first switch K11 corresponding to the pixel electrode S11, a storage capacitor S12, and a second switch K12 corresponding to the storage capacitor S12, the pixel unit P11 further includes: a test capacitor S13 and a third switch K13 corresponding to the test capacitor S13.

[0060] In the embodiments of the present application, considering that if the measurement module is directly used to convert the charges of the storage capacitor into digital signals for characterizing pixel values, there may be a problem of overexposure of the fingerprint image caused by the large charges in the storage capacitor. Therefore, a test capacitor is added behind each storage capacitor of the pixel unit to share the charges in the storage capacitor. For example, if the capacitance of the test capacitor is the same as that of the storage capacitor, the test capacitor can share half of the charges in the storage capacitor. The measurement module is used to convert the charges of the test capacitor into digital signals for characterizing pixel values to obtain the fingerprint image, thereby preventing the problem of overexposure of the fingerprint image.

[0061] In some embodiments provided by the present application, based on Figure 2 the embodiments shown, each pixel unit may further include: a third switch; the pixel array may further include: N test capacitors corresponding to N columns of pixel units respectively and N fourth switches corresponding to the N test capacitors respectively. The storage capacitors of the pixel units in the same column are respectively electrically connected to the test capacitor corresponding to that column through their respective third switches, and the test capacitors are connected to the ground through the fourth switches.

[0062] Exemplarily, as Figure 4As shown, in addition to including M*N pixel units such as P11 to PMN, the pixel array further includes: N test capacitors respectively corresponding to N columns of pixel units and N fourth switches respectively corresponding to the N test capacitors. For example, a test capacitor S13 in the first column of the "KC" row and the fourth switch K14 corresponding to the test capacitor S13. The other test capacitors and the corresponding fourth switches in the "KC" row are similar and will not be elaborated here.

[0063] Still taking the pixel unit P11 in the first row and the first column of the pixel array as an example, the pixel unit P11 includes, in addition to: a pixel electrode S11, a first switch K11 corresponding to the pixel electrode S11, a storage capacitor S12, and a second switch K12 corresponding to the storage capacitor S12, also includes: a third switch K13.

[0064] From Figure 3 and Figure 4 it can be seen that: Figure 3 In the pixel array of the fingerprint sensing chip in the shown embodiment, each pixel unit has a dedicated test capacitor. Figure 4 In the pixel array of the fingerprint sensing chip in the shown embodiment, the pixel units in the same column share a test capacitor. Figure 4 The difference between the embodiment and Figure 3 the embodiment is that the pixel units in the same column share a test capacitor. Compared with Figure 3 the embodiment, Figure 4 the embodiment can reduce the number of test capacitors in the pixel array. On the one hand, it can reduce costs, and on the other hand, it can save space, reduce the size of the pixel array, thereby reducing the volume of the fingerprint sensing chip and increasing the integration degree.

[0065] In the embodiments of the present application, on the one hand, considering that if the measurement module directly converts the charge of the storage capacitor into a digital signal for characterizing the pixel value, there may be a problem of overexposure of the fingerprint image caused by a large charge in the storage capacitor. Therefore, a test capacitor is added behind each storage capacitor of the pixel unit to share the charge in the storage capacitor. For example, if the capacitance of the test capacitor is the same as that of the storage capacitor, the test capacitor can share half of the charge in the storage capacitor. The measurement module converts the charge of the test capacitor into a digital signal for characterizing the pixel value to obtain the fingerprint image, thereby preventing the problem of overexposure of the fingerprint image. On the other hand, considering the cost issue, all pixel units in the same column can share a test capacitor, so that only a small number of test capacitors need to be used in the pixel array to achieve fingerprint image acquisition, reducing the acquisition cost of the fingerprint image.

[0066] In some embodiments provided by the present application, in Figure 2Based on the illustrated embodiments, each pixel unit may further include: a third switch; the pixel array may further include: M test capacitors corresponding to M rows of pixel units respectively and M fourth switches corresponding to the M test capacitors respectively. The storage capacitors of the pixel units in the same row are electrically connected to the test capacitor corresponding to that row through their respective third switches, and the test capacitor is connected to the ground through the fourth switch.

[0067] Exemplarily, as Figure 5 illustrated, in addition to including M*N pixel units such as P11 to PMN, the pixel array further includes: M test capacitors corresponding to M rows of pixel units respectively and M fourth switches corresponding to the M test capacitors respectively. For example, a test capacitor S13 in the first row of the "KC" column and a fourth switch K14 corresponding to the test capacitor S13. The other test capacitors and the corresponding fourth switches in the "KC" column are similar and will not be elaborated here.

[0068] Still taking the pixel unit P11 in the first row and first column of the pixel array as an example, the pixel unit P11, in addition to including: a pixel electrode S11, a first switch K11 corresponding to the pixel electrode S11, a storage capacitor S12, and a second switch K12 corresponding to the storage capacitor S12, further includes: a third switch K13.

[0069] From Figure 3 and Figure 5 it can be seen that: Figure 3 in the pixel array of the fingerprint sensing chip of the illustrated embodiments, each pixel unit has a dedicated test capacitor. Figure 5 in the pixel array of the fingerprint sensing chip of the illustrated embodiments, the pixel units in the same row share a test capacitor. Figure 5 The difference between the embodiment and Figure 3 the embodiment is that the pixel units in the same row share a test capacitor. Compared with Figure 3 the embodiment, Figure 5 the embodiment can reduce the number of test capacitors in the pixel array. On the one hand, it can reduce costs, and on the other hand, it can save space, reduce the size of the pixel array, thereby reducing the volume of the fingerprint sensing chip and increasing the integration degree.

[0070] In the embodiments of the present application, on the one hand, considering that if the measurement module directly converts the charge of the storage capacitor into a digital signal for characterizing the pixel value, there may be a problem of overexposure of the fingerprint image caused by the large charge in the storage capacitor. Therefore, a test capacitor is added behind each storage capacitor of the pixel unit to share the charge in the storage capacitor. For example, if the capacitance of the test capacitor is the same as that of the storage capacitor, the test capacitor can share half of the charge in the storage capacitor. The measurement module is used to convert the charge of the test capacitor into a digital signal for characterizing the pixel value to obtain the fingerprint image, thereby preventing the problem of overexposure of the fingerprint image. On the other hand, considering the cost issue, all pixel units in the same row can share a test capacitor, so that only a small number of test capacitors need to be used in the pixel array to realize fingerprint image acquisition, reducing the acquisition cost of the fingerprint image.

[0071] After introducing the fingerprint sensing chip, a capacitive fingerprint module provided by the embodiments of the present application will be introduced.

[0072] In some embodiments provided by the present application, the capacitive fingerprint module may include: the fingerprint sensing chip in any of the above embodiments, and may further include: a driving module and a measurement module; the driving module is used to output a driving signal to each pixel electrode, and the measurement module is used to convert the charge into a digital signal for characterizing the pixel value; the pixel array of the fingerprint sensing chip is electrically connected to the driving module, and the pixel array of the fingerprint sensing chip is electrically connected to the measurement module.

[0073] In the embodiments of the present application, at least one of the driving module and the measurement module may be located inside the fingerprint sensing chip or completely independent of the fingerprint sensing chip, and the flexibility of chip design is relatively high.

[0074] In some embodiments, the driving module and the measurement module are completely independent of the fingerprint sensing chip. As Figure 6 shown, the capacitive fingerprint module 600 may include: a driving module 610, a fingerprint sensing chip 620, and a measurement module 630.

[0075] In some embodiments, the driving module and / or the measurement module is located inside the fingerprint sensing chip.

[0076] Exemplarily, as Figure 7 shown, the capacitive fingerprint module 700 may include: a fingerprint sensing chip 710, and the fingerprint sensing chip 710 may include: a driving module 711, a pixel array 712, and a measurement module 713.

[0077] In the embodiments of the present application, the driving module can provide driving signals for the pixel electrodes in each row of pixel units of the pixel array, that is, "row driving"; or the driving module can provide driving signals for the pixel electrodes in each column of pixel units of the pixel array, that is, "column driving". In practical applications, the connection manner between the driving module and the pixel array in the fingerprint sensing chip can be flexibly configured according to different driving methods.

[0078] In the embodiments of the present application, each measurement module may include: an operational amplifier and an analog-to-digital converter; wherein, the operational amplifier and the analog-to-digital converter are electrically connected, the operational amplifier is used to convert charge into a voltage value, and the analog-to-digital converter is used to convert the voltage value output by the operational amplifier into a digital signal for characterizing the pixel value. Alternatively, the measurement module may also adopt other circuit structures, and the embodiments of the present application do not limit this. In practical applications, the number of measurement modules and the connection manner between the measurement modules and the pixel array can be flexibly configured according to the circuit structure of the pixel array in the fingerprint sensing chip.

[0079] As can be seen from the above embodiments, in this embodiment, each pixel unit of the pixel array of the capacitive fingerprint module has a storage capacitor, that is, each pixel unit exclusively has a storage capacitor. Therefore, it is possible to charge and collect charges in parallel, shorten the charge collection time of the pixel array, thereby shorten the entire image acquisition time, and further shorten the fingerprint recognition time.

[0080] For ease of understanding, after each embodiment of the capacitive fingerprint module, the image acquisition process of the capacitive fingerprint module is described in conjunction with the corresponding fingerprint image acquisition method.

[0081] Corresponding to the above capacitive fingerprint module, Figure 8 is a flowchart of a fingerprint image acquisition method provided by the embodiments of the present application. As Figure 8 shown, the method may include the following steps: step 801, step 802, and step 803;

[0082] In step 801, control each first switch in the capacitive fingerprint module to switch to the conducting state, output a driving signal from the driving module to each pixel electrode of the pixel array, and after the driving signal output duration reaches the first duration, control each first switch to switch to the off state and stop outputting the driving signal.

[0083] In the embodiment of the present application, each first switch in the capacitive fingerprint module is controlled to be switched to the conducting state, and a driving signal is output to each pixel electrode of the pixel array through the driving module, so that when a user's finger presses or touches above the pixel electrode, a pixel capacitor is formed. The driving module outputs the driving signal for a period of time to charge all the pixel capacitors. After the output duration of the driving signal reaches the first duration, each first switch is controlled to be switched to the off state, and the output of the driving signal is stopped, thereby completing a charge acquisition of the entire pixel array.

[0084] In step 802, each second switch in the capacitive fingerprint module is controlled to be switched to the conducting state. After the conducting state of the second switch is maintained for the second duration, each second switch is controlled to be switched to the off state; the above all steps are repeatedly executed K times, where K is an integer greater than 2.

[0085] In the embodiment of the present application, after a charge acquisition of the entire pixel array is completed, each second switch in the capacitive fingerprint module is controlled to be switched to the conducting state, and the conducting state lasts for a period of time, so that the pixel capacitor corresponding to each pixel unit charges the storage capacitor, and part of the charge is transferred from the pixel capacitor to the storage capacitor. After the conducting state of the second switch is maintained for the second duration, each second switch is controlled to be switched to the off state, thereby completing a charge storage of the entire pixel array.

[0086] In the embodiment of the present application, since the charge collected in a single time is less, the above two steps are repeated K times to complete K times of charge acquisition and storage of the entire pixel array.

[0087] In step 803, the measurement module of the capacitive fingerprint module is controlled to convert the charge output by the pixel array into a digital signal for characterizing the pixel value, and a fingerprint image is obtained.

[0088] As can be seen from the above embodiments, in this embodiment, since each pixel unit of the capacitive fingerprint module includes, in addition to a pixel electrode and a first switch corresponding to the pixel electrode, a storage capacitor and a second switch corresponding to the storage capacitor, when fingerprint image acquisition is performed based on the capacitive fingerprint module, parallel charging acquisition and charge storage of the pixel electrodes of all pixel units of the capacitive fingerprint module can be realized. On the one hand, the image acquisition duration of the capacitive fingerprint module is shortened, thereby shortening the fingerprint recognition time; on the other hand, the edge electric field of the pixel electrode is better during parallel charging, and finally there will be more charge on the pixel electrode, the pixel values of each pixel unit obtained are larger, and the fingerprint image is clearer.

[0089] In some embodiments provided by the present application, the fingerprint sensing chip of the capacitive fingerprint module includes Figure 2The pixel array shown, the pixel array includes: M*N pixel units; each pixel unit includes: a pixel electrode, a first switch corresponding to the pixel electrode, a storage capacitor, and a second switch corresponding to the storage capacitor; the number of measurement modules of the capacitive fingerprint module is the same as the number of pixel units; each storage capacitor of each pixel unit is electrically connected to a measurement module respectively.

[0090] Correspondingly, step 803 above may include the following steps: step 8031;

[0091] In step 8031, control each measurement module in the capacitive fingerprint module to convert the charge in each storage capacitor into a digital signal for characterizing the pixel value, and obtain a fingerprint image.

[0092] In the embodiments of the present application, after completing K times of charge acquisition and storage, control M*N test modules to simultaneously convert the charge in M*N storage capacitors into a digital signal for characterizing the pixel value, and obtain a fingerprint image.

[0093] It can be seen that in the embodiments of the present application, a measurement module can be configured for each storage capacitor in the pixel array in the capacitive fingerprint module. After parallel charging and storing charges for all pixel units in the pixel array, each measurement module is used to simultaneously convert the charge of each storage capacitor in the pixel array into a digital signal for characterizing the pixel value, achieving the purpose of parallel measurement after parallel charging, further shortening the image acquisition time of the capacitive fingerprint module and shortening the fingerprint recognition time.

[0094] In some embodiments provided by the present application, the fingerprint sensing chip of the capacitive fingerprint module includes Figure 3 The pixel array shown, the pixel array includes: M*N pixel units; each pixel unit includes: a pixel electrode, a first switch corresponding to the pixel electrode, a storage capacitor, a second switch corresponding to the storage capacitor, a test capacitor, and a third switch corresponding to the test capacitor, the storage capacitor is electrically connected to the test capacitor through the third switch; the number of measurement modules of the capacitive fingerprint module is the same as the number of pixel units; each test capacitor of each pixel unit is electrically connected to a measurement module respectively.

[0095] Correspondingly, step 803 above may include the following steps: step 8032 and step 8033;

[0096] In step 8032, control each third switch in the capacitive fingerprint module to switch to the on state, and after maintaining the on state of the third switch for a third time period, control each third switch to switch to the off state.

[0097] In the embodiment of the present application, each third switch in the capacitive fingerprint module is controlled to be switched to the conducting state, and the conducting state lasts for a period of time, so that each storage capacitor charges the test capacitor connected thereto, and a part of the charge is transferred from the storage capacitor to the test capacitor. After the conducting state of the third switch is maintained for a third period of time, each third switch is controlled to be switched to the off state, thereby completing the charge shunting.

[0098] In step 8033, each measurement module in the capacitive fingerprint module converts the charge in each test capacitor into a digital signal for characterizing the pixel value, and a fingerprint image is obtained.

[0099] In the embodiment of the present application, after the charge shunting is completed, M×N test modules are controlled to simultaneously convert the charge in M×N test capacitors into digital signals for characterizing pixel values, and a fingerprint image is obtained.

[0100] It can be seen that in the embodiment of the present application, a test capacitor can be configured for each storage capacitor of the pixel array of the capacitive fingerprint module to shunt the charge of the storage capacitor, so as to avoid the problem of overexposure of the fingerprint image caused by excessive charge. At the same time, a measurement module is configured for each test capacitor. After parallel charging and collecting the stored charge of all pixel units in the pixel array, each measurement module is used to simultaneously convert the charge of each test capacitor in the pixel array into a digital signal for characterizing the pixel value, achieving the purpose of parallel measurement after parallel charging, further shortening the image acquisition time of the capacitive fingerprint module and shortening the fingerprint recognition time.

[0101] In some embodiments provided by the present application, the fingerprint sensing chip of the capacitive fingerprint module includes Figure 4 the pixel array shown in the figure. The pixel array includes: M×N pixel units, N test capacitors respectively corresponding to N columns of pixel units, and N fourth switches respectively corresponding to the N test capacitors. Each pixel unit includes: a pixel electrode, a first switch corresponding to the pixel electrode, a storage capacitor, a second switch corresponding to the storage capacitor, and a third switch; the storage capacitors of the pixel units in the same column are respectively electrically connected to the test capacitor corresponding to the column through their respective third switches, and the test capacitor is connected to the ground through the fourth switch; the number of measurement modules of the capacitive fingerprint module is the same as the number of columns of pixel units, and each test capacitor is electrically connected to a measurement module respectively.

[0102] Correspondingly, the above step 803 may include the following steps: step 8034, step 8035, and step 8036;

[0103] In step 8034, each third switch of the pixel units in the i-th row of the capacitive fingerprint module is controlled to be switched to the conducting state, and each third switch of the pixel units in the remaining other rows is controlled to be switched to the off state. After the state of the third switch is maintained for a third duration, each third switch of the pixel units in the i-th row is controlled to be switched to the off state.

[0104] In the embodiment of the present application, each third switch of the pixel units in the i-th row of the capacitive fingerprint module is controlled to be switched to the conducting state, and each third switch of the pixel units in the remaining other rows is controlled to be switched to the off state, and this state is maintained for a period of time so that each storage capacitor in the i-th row charges the respective connected test capacitor, and part of the charge is transferred from the storage capacitor to the test capacitor. After the state of the third switch is maintained for the third duration, each third switch of the pixel units in the i-th row is controlled to be switched to the off state, thereby completing the charge shunting of the storage capacitors in the i-th row.

[0105] In step 8035, the measurement module in the capacitive fingerprint module is controlled to convert the charge in each test capacitor into a digital signal for characterizing the pixel value, obtain the pixel value of the i-th row of the fingerprint image, and control the fourth switch corresponding to each test capacitor to be switched to the ground short-circuit state. i is incremented by 1 and the above step 8034 is executed again until i = M, and the initial value of i is 1.

[0106] In the embodiment of the present application, for the charge transferred from the storage capacitor in the i-th row to the test capacitor, the measurement module in the capacitive fingerprint module converts the charge in each test capacitor into a digital signal for characterizing the pixel value, obtains the pixel value of the i-th row of the fingerprint image, and then controls the fourth switch corresponding to each test capacitor to be switched to the ground short-circuit state to empty the charge in each test capacitor and prepare for the charge shunting of the (i + 1)-th row.

[0107] Exemplarily, starting from the pixel units in the first row, each third switch of the pixel units in the first row of the capacitive fingerprint module is controlled to be switched to the conducting state, and each third switch of the pixel units in the remaining other rows is controlled to be switched to the off state. After the state of the above third switch is maintained for the third duration, each third switch of the pixel units in the first row is controlled to be switched to the off state, so that the charge of each storage capacitor in the first row is transferred to each test capacitor, completing the charge shunting of the first row. Then, the measurement modules are controlled to convert the charge of the test capacitors connected to them into digital signals for characterizing the pixel values, and obtain the pixel values of the first row.

[0108] After that, control the fourth switch corresponding to each test capacitor to switch to the ground short - circuit state to empty the charge of the test capacitor, and continue the second - row charge shunting. Then, control each measurement module to convert the charge of the test capacitor connected thereto into a digital signal for characterizing the pixel value, and obtain the pixel values of the second row. And so on, finally obtain the pixel values of the Mth row.

[0109] In step 8036, after obtaining the pixel values of the M rows of the fingerprint image, generate a fingerprint image according to the pixel values of the M rows.

[0110] In the embodiments of the present application, after obtaining the pixel values of the M rows of the fingerprint image, a fingerprint image can be generated according to the row arrangement order of each pixel unit in the pixel array and the pixel values of each row.

[0111] It can be seen that in the embodiments of the present application, a test capacitor can be configured for each column - storage capacitor of the pixel array of the capacitive fingerprint module to shunt the charge of the storage capacitor. On the one hand, it can avoid the problem of over - exposure of the fingerprint image caused by excessive charge. On the other hand, it can reduce costs. At the same time, a measurement module is configured for each test capacitor. After parallel charging all pixel units in the pixel array to collect the stored charge, each measurement module simultaneously converts the charge of each test capacitor in the pixel array into a digital signal for characterizing the pixel value, achieving the purpose of row - by - row measurement after parallel charging, shortening the image acquisition time of the capacitive fingerprint module, and thus shortening the fingerprint recognition time.

[0112] In some embodiments provided by the present application, the fingerprint sensing chip of the capacitive fingerprint module includes Figure 5 the pixel array shown in the figure. The pixel array includes: M * N pixel units, M test capacitors corresponding to M rows of pixel units respectively, and M fourth switches corresponding to the M test capacitors respectively. Each pixel unit includes: a pixel electrode, a first switch corresponding to the pixel electrode, a storage capacitor, a second switch corresponding to the storage capacitor, and a third switch. The storage capacitors of the pixel units in the same row are respectively electrically connected to the test capacitor corresponding to that row through their respective third switches, and the test capacitor is connected to the ground through the fourth switch. The number of measurement modules of the capacitive fingerprint module is the same as the number of rows of pixel units, and each test capacitor is electrically connected to a measurement module respectively.

[0113] Correspondingly, the above - mentioned step 803 may include the following steps: step 8037, step 8038, and step 8039;

[0114] In step 8037, control each third switch of the pixel units in the j-th column of the capacitive fingerprint module to switch to the on state, and control each third switch of the pixel units in the remaining other columns to switch to the off state. After the state of the third switch is maintained for a third duration, control each third switch of the pixel units in the j-th column to switch to the off state.

[0115] In the embodiment of the present application, control each third switch of the pixel units in the j-th column of the capacitive fingerprint module to switch to the on state, and control each third switch of the pixel units in the remaining other columns to switch to the off state, and maintain this state for a period of time, so that each storage capacitor in the j-th column charges the respective connected test capacitor, and part of the charge is transferred from the storage capacitor to the test capacitor. After the state of the third switch is maintained for a third duration, control each third switch of the pixel units in the j-th column to switch to the off state, thereby completing the charge shunting of the storage capacitors in the j-th column.

[0116] In step 8038, control the measurement module in the capacitive fingerprint module to convert the charge in each test capacitor into a digital signal for characterizing the pixel value, obtain the pixel value of the j-th column of the fingerprint image, and control the fourth switch corresponding to each test capacitor to switch to the ground short circuit state. Increment j by 1 and return to execute the above step 8037 until j = N, where the initial value of j is 1.

[0117] In the embodiment of the present application, for the charge transferred from the storage capacitor in the j-th column to the test capacitor, the measurement module in the capacitive fingerprint module converts the charge in each test capacitor into a digital signal for characterizing the pixel value, obtains the pixel value of the j-th column of the fingerprint image, and then controls the fourth switch corresponding to each test capacitor to switch to the ground short circuit state to empty the charge in each test capacitor and prepare for the charge shunting of the (j + 1)-th column.

[0118] Exemplarily, starting from the first column of pixel units, control each third switch of the pixel units in the first column of the capacitive fingerprint module to switch to the on state, and control each third switch of the pixel units in the remaining other columns to switch to the off state. After the state of the above third switch is maintained for a third duration, control each third switch of the pixel units in the first column to switch to the off state, so that the charge of each storage capacitor in the first column is transferred to each test capacitor, completing the charge shunting of the first column. Then control each measurement module to convert the charge of the test capacitor connected thereto into a digital signal for characterizing the pixel value, and obtain the pixel value of the first column.

[0119] After that, control the fourth switch corresponding to each test capacitor to switch to a state of being shorted to the ground to empty the charge of the test capacitor, and continue with the second-column charge shunting. After that, control each measurement module to convert the charge of the test capacitor connected thereto into a digital signal for characterizing the pixel value, and obtain the pixel values of the second column. By analogy, the pixel values of the Nth column are finally obtained.

[0120] In step 8039, after obtaining the pixel values of N columns of the fingerprint image, generate a fingerprint image according to the pixel values of the N columns.

[0121] In the embodiment of the present application, after obtaining the pixel values of N columns of the fingerprint image, a fingerprint image can be generated according to the column arrangement order of each pixel unit in the pixel array and the pixel values of each column.

[0122] It can be seen that in the embodiment of the present application, a test capacitor can be configured for each row storage capacitor of the pixel array of the capacitive fingerprint module to shunt the charge of the storage capacitor. On the one hand, it can avoid the problem of overexposure of the fingerprint image caused by excessive charge. On the other hand, it can reduce costs; at the same time, a measurement module is configured for each test capacitor. After parallel charging and collecting the stored charge of all pixel units in the pixel array, each measurement module is used to convert the charge of each test capacitor in the pixel array into a digital signal for characterizing the pixel value at the same time, achieving the purpose of column-by-column measurement after parallel charging, shortening the image acquisition time of the capacitive fingerprint module, and thus shortening the fingerprint recognition time. Figure 9 is a schematic structural diagram of a fingerprint image acquisition device provided by an embodiment of the present application, as Figure 9 shown, the fingerprint image acquisition device 900 may include: a first control module 910, a second control module 920, and a third control module 930;

[0123] The first control module 910 is configured to control each first switch in the capacitive fingerprint module to switch to a conducting state, output a driving signal to each pixel electrode of the pixel array through a driving module, and after the driving signal output duration reaches a first duration, control each of the first switches to switch to an off state and stop outputting the driving signal;

[0124] The second control module 920 is configured to control each second switch in the capacitive fingerprint module to switch to a conducting state, and after the conducting state of the second switch is maintained for a second duration, control each of the second switches to switch to an off state; repeat all the above steps K times, where K is an integer greater than 2;

[0125] The third control module 930 is configured to control the measurement module in the capacitive fingerprint module to convert the charge output by the pixel array into a digital signal for characterizing the pixel value, and obtain a fingerprint image.

[0126] As can be seen from the above embodiments, in this embodiment, since each pixel unit of the capacitive fingerprint module includes, in addition to a pixel electrode and a first switch corresponding to the pixel electrode, a storage capacitor and a second switch corresponding to the storage capacitor, when fingerprint image acquisition is performed based on the capacitive fingerprint module, parallel charging of the pixel electrodes of all pixel units of the capacitive fingerprint module can be achieved to collect and store charges. On the one hand, the image acquisition time of the capacitive fingerprint module is shortened, thereby shortening the fingerprint recognition time. On the other hand, the edge electric field of the pixel electrodes is better during parallel charging. Eventually, there will be more charges on the pixel electrodes, the pixel values of each pixel unit obtained will be larger, and the fingerprint image will be clearer.

[0127] Optionally, as an embodiment, the pixel array may include: M*N pixel units; each pixel unit includes: a pixel electrode, a first switch corresponding to the pixel electrode, a storage capacitor, and a second switch corresponding to the storage capacitor; the number of measurement modules is the same as the number of pixel units; the storage capacitor of each pixel unit is electrically connected to a measurement module respectively;

[0128] The third control module 930 may include:

[0129] A first control sub-module, configured to control each measurement module in the capacitive fingerprint module to convert the charges in each storage capacitor into digital signals for characterizing pixel values, so as to obtain a fingerprint image.

[0130] Optionally, as an embodiment, the pixel array may include: M*N pixel units; each pixel unit includes: a pixel electrode, a first switch corresponding to the pixel electrode, a storage capacitor, a second switch corresponding to the storage capacitor, a test capacitor, and a third switch corresponding to the test capacitor, and the storage capacitor is electrically connected to the test capacitor through its respective third switch; the number of measurement modules is the same as the number of pixel units; the test capacitor of each pixel unit is electrically connected to a measurement module respectively;

[0131] The third control module 930 may include:

[0132] A second control sub-module, configured to control each third switch in the capacitive fingerprint module to switch to a conducting state, and after maintaining the conducting state of the third switch for a third time period, control each third switch to switch to a disconnected state;

[0133] A third control sub-module, configured to control each measurement module in the capacitive fingerprint module to convert the charges in each test capacitor into digital signals for characterizing pixel values, so as to obtain a fingerprint image.

[0134] Optionally, as an embodiment, the pixel array may include: M*N pixel units, N test capacitors respectively corresponding to N columns of pixel units, and N fourth switches respectively corresponding to the N test capacitors. Each pixel unit includes: a pixel electrode, a first switch corresponding to the pixel electrode, a storage capacitor, a second switch corresponding to the storage capacitor, and a third switch. The storage capacitors of the pixel units in the same column are respectively electrically connected to the test capacitor corresponding to that column through their respective third switches, and the test capacitor is connected to the ground through the fourth switch. The number of measurement modules is the same as the number of columns of pixel units, and each test capacitor is electrically connected to a measurement module respectively;

[0135] The third control module 930 may include:

[0136] A fourth control sub-module, configured to control each third switch of the pixel units in the i-th row in the capacitance fingerprint module to be switched to the on state, and control each third switch of the pixel units in the remaining other rows to be switched to the off state. After the state of the third switch is maintained for a third duration, control each third switch of the pixel units in the i-th row to be switched to the off state;

[0137] A fifth control sub-module, configured to control the measurement module in the capacitance fingerprint module to convert the charge in each test capacitor into a digital signal for characterizing the pixel value, obtain the pixel value of the i-th row of the fingerprint image, and control the fourth switch corresponding to each test capacitor to be switched to the short-circuit state to the ground. Increment i by 1 and return to execute the step of controlling each third switch of the pixel units in the i-th row in the capacitance fingerprint module to be switched to the on state until i = M, and the initial value of i is 1;

[0138] A first generation sub-module, configured to generate the fingerprint image according to the pixel values of the M rows after obtaining the pixel values of the M rows of the fingerprint image.

[0139] Optionally, as an embodiment, the pixel array may include: M*N pixel units, M test capacitors respectively corresponding to M rows of pixel units, and M fourth switches respectively corresponding to the M test capacitors. Each pixel unit includes: a pixel electrode, a first switch corresponding to the pixel electrode, a storage capacitor, a second switch corresponding to the storage capacitor, and a third switch. The storage capacitors of the pixel units in the same row are electrically connected to the test capacitor corresponding to that row through the third switch, and the test capacitor is connected to the ground through the fourth switch. The number of measurement modules is the same as the number of rows of pixel units, and each test capacitor is electrically connected to a measurement module respectively;

[0140] The third control module 930 may include:

[0141] The sixth control sub-module is configured to control each third switch of the pixel units in the j-th column of the capacitive fingerprint module to be switched to the on state, and control each third switch of the pixel units in the remaining other columns to be switched to the off state. After the state of the third switch is maintained for a third duration, control each third switch of the pixel units in the j-th column to be switched to the off state;

[0142] The seventh control sub-module is configured to control the measurement module in the capacitive fingerprint module to convert the charges in each test capacitor into digital signals for characterizing pixel values, obtain the pixel values of the j-th column of the fingerprint image, and control the fourth switches corresponding to the respective test capacitors to be switched to a state of being short-circuited to the ground. Increment j by 1 and return to execute the step of controlling each third switch of the pixel units in the j-th column of the capacitive fingerprint module to be switched to the on state until j = N, where the initial value of j is 1;

[0143] The second generation sub-module is configured to generate the fingerprint image according to the pixel values of the N columns after obtaining the pixel values of the N columns of the fingerprint image.

[0144] Any step and the specific operations in any step in the embodiments of the fingerprint image acquisition method provided in this application can be completed by the corresponding modules in the fingerprint image acquisition device. The processes of the corresponding operations completed by the various modules in the fingerprint image acquisition device refer to the processes of the corresponding operations described in the embodiments of the fingerprint image acquisition method.

[0145] For the device embodiments, since they are basically similar to the method embodiments, the description is relatively simple. For the relevant parts, refer to the partial description of the method embodiments.

[0146] Figure 10 It is a structural block diagram of an electronic device provided in an embodiment of this application. The electronic device includes a processing component 1022, which further includes one or more processors, and memory resources represented by a memory 1032 for storing instructions executable by the processing component 1022, such as application programs. The application programs stored in the memory 1032 may include one or more modules each corresponding to a set of instructions. In addition, the processing component 1022 is configured to execute instructions to perform the above method.

[0147] The electronic device may further include a power supply component 1026 configured to perform power management of the electronic device, a wired or wireless network interface 1050 configured to connect the electronic device to a network, and an input / output (I / O) interface 1058. The electronic device may operate based on an operating system stored in the memory 1032, such as Windows ServerTM, MacOS XTM, UnixTM, LinuxTM, FreeBSDTM or the like. The electronic device may further include a capacitive fingerprint module 1060 for collecting fingerprint images.

[0148] According to still another embodiment of the present application, the present application further provides a computer-readable storage medium having stored thereon computer programs / instructions, which when executed by a processor, implement the steps in the fingerprint image acquisition method as described in any one of the above embodiments.

[0149] According to still another embodiment of the present application, the present application further provides a computer program product including computer programs / instructions, which when executed by a processor, implement the steps in the fingerprint image acquisition method as described in any one of the above embodiments.

[0150] Each embodiment in this specification is described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts among the various embodiments can be referred to each other.

[0151] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a device, or a computer program product. Therefore, the embodiments of the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the embodiments of the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memories, CD-ROMs, optical memories, etc.) containing computer-usable program codes.

[0152] The embodiments of the present application are described with reference to the flowcharts and / or block diagrams of methods, terminal devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowcharts and / or block diagrams, and the combination of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing terminal devices to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing terminal devices generate for implementing in the process Figure 1 one process or multiple processes and / or blocks Figure 1A device for the functions specified in one or more boxes.

[0153] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing terminal device to work in a specific manner, such that the instructions stored in the computer-readable memory produce a manufactured article including an instruction device that implements the functions specified in one Figure 1 process or more processes and / or boxes Figure 1 a box or more boxes.

[0154] Although the preferred embodiments of the embodiments of the present application have been described, those skilled in the art can make additional changes and modifications once they learn the basic creative concepts. Therefore, the appended claims are intended to be construed to include the preferred embodiments and all changes and modifications falling within the scope of the embodiments of the present application.

[0155] Finally, it should also be noted that in this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article or terminal device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or terminal device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or terminal device comprising the element.

[0156] The above has introduced in detail a fingerprint sensing chip, a capacitive fingerprint module and a fingerprint image acquisition method provided by the present application. Specific examples are used in this article to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A fingerprint sensing chip, characterized in that, Comprising a pixel array, the pixel array comprising: M*N pixel units, where M is the number of rows of pixel units in the pixel array, N is the number of columns of pixel units in the pixel array, and both M and N are integers greater than 1; Each of the pixel units comprises: a pixel electrode, a first switch corresponding to the pixel electrode, a storage capacitor, and a second switch corresponding to the storage capacitor, the pixel electrode being electrically connected to a driving module through the first switch, the pixel electrode being electrically connected to the storage capacitor through the second switch, and the storage capacitor being used for storing charges generated by the pixel electrode.

2. The fingerprint sensing chip according to claim 1, wherein Each pixel unit further comprises: a test capacitor and a third switch corresponding to the test capacitor; The storage capacitor is electrically connected to the test capacitor through the third switch.

3. The fingerprint sensing chip according to claim 1, wherein Each pixel unit further comprises: a third switch; The pixel array further comprises: N test capacitors respectively corresponding to N columns of pixel units and N fourth switches respectively corresponding to the N test capacitors, the storage capacitors of the pixel units in the same column being respectively electrically connected to the test capacitor corresponding to that column through their respective third switches, and the test capacitors being electrically connected to ground through the fourth switches; or, The pixel array further comprises: M test capacitors respectively corresponding to M rows of pixel units and M fourth switches respectively corresponding to the M test capacitors, the storage capacitors of the pixel units in the same row being respectively electrically connected to the test capacitor corresponding to that row through their respective third switches, and the test capacitors being electrically connected to ground through the fourth switches.

4. A capacitive fingerprint module, characterized in that, Comprising the fingerprint sensing chip according to any one of claims 1-3, further comprising a driving module and a measuring module; The driving module is used for outputting a driving signal to each pixel electrode, and the measuring module is used for converting charges into digital signals for characterizing pixel values; The pixel array of the fingerprint sensing chip is electrically connected to the driving module, and the pixel array of the fingerprint sensing chip is electrically connected to the measuring module.

5. The capacitive fingerprint module according to claim 4, wherein The driving module and / or the measuring module is / are located inside the fingerprint sensing chip.

6. The capacitive fingerprint module according to claim 4 or 5, wherein The pixel array comprises: M*N pixel units; Each pixel unit comprises: a pixel electrode, a first switch corresponding to the pixel electrode, a storage capacitor, and a second switch corresponding to the storage capacitor; The number of the measuring modules is the same as the number of the pixel units; The storage capacitor of each pixel unit is electrically connected to one measuring module respectively.

7. The capacitive fingerprint module according to claim 4 or 5, wherein The pixel array comprises: M*N pixel units; Each pixel unit comprises: a pixel electrode, a first switch corresponding to the pixel electrode, a storage capacitor, a second switch corresponding to the storage capacitor, a test capacitor, and a third switch corresponding to the test capacitor, the storage capacitor being electrically connected to the test capacitor through the third switch; The number of the measuring modules is the same as the number of the pixel units; The test capacitor of each pixel unit is electrically connected to one measuring module respectively.

8. The capacitive fingerprint module according to claim 4 or 5, wherein The pixel array includes: M*N pixel units, and each pixel unit includes: a pixel electrode, a first switch corresponding to the pixel electrode, a storage capacitor, a second switch corresponding to the storage capacitor, and a third switch; The pixel array further includes: N test capacitors corresponding to N columns of pixel units respectively, and N fourth switches corresponding to the N test capacitors respectively. The storage capacitors of the pixel units in the same column are respectively electrically connected to the test capacitor corresponding to this column through their respective third switches, and the test capacitor is connected to the ground through the fourth switch; the number of measurement modules is the same as the number of columns of pixel units, and each test capacitor is electrically connected to a measurement module respectively; or, The pixel array further includes: M test capacitors corresponding to M rows of pixel units respectively, and M fourth switches corresponding to the M test capacitors respectively. The storage capacitors of the pixel units in the same row are respectively electrically connected to the test capacitor corresponding to this row through their respective third switches, and the test capacitor is connected to the ground through the fourth switch; the number of measurement modules is the same as the number of rows of pixel units, and each test capacitor is electrically connected to a measurement module respectively.

9. The capacitive fingerprint module according to claim 4 or 5, characterized in that, Each measurement module includes: an operational amplifier and an analog-to-digital converter; The operational amplifier is electrically connected to the analog-to-digital converter. The operational amplifier is used to convert charge into a voltage value, and the analog-to-digital converter is used to convert the voltage value output by the operational amplifier into a digital signal for characterizing a pixel value.

10. A fingerprint image acquisition method for acquiring a fingerprint image based on the capacitive fingerprint module according to any one of claims 4-9, characterized in that, The method includes: Controlling each first switch in the capacitive fingerprint module to switch to the conducting state, outputting a driving signal to each pixel electrode of the pixel array through a driving module, after the driving signal output duration reaches a first duration, controlling each of the first switches to switch to the off state, and stopping outputting the driving signal; Controlling each second switch in the capacitive fingerprint module to switch to the conducting state, after the conducting state of the second switch is maintained for a second duration, controlling each of the second switches to switch to the off state; repeating all the above steps K times, where K is an integer greater than 2; Controlling the measurement module of the capacitive fingerprint module to convert the charge output by the pixel array into a digital signal for characterizing a pixel value, and obtaining a fingerprint image.

11. The method according to claim 10, characterized in that, The pixel array includes: M*N pixel units; each pixel unit includes: a pixel electrode, a first switch corresponding to the pixel electrode, a storage capacitor, and a second switch corresponding to the storage capacitor; the number of measurement modules is the same as the number of pixel units; the storage capacitor of each pixel unit is electrically connected to a measurement module respectively; The controlling the measurement module of the capacitive fingerprint module to convert the charge output by the pixel array into a digital signal for characterizing a pixel value and obtaining a fingerprint image includes: Controlling each measurement module in the capacitive fingerprint module to convert the charge in each storage capacitor into a digital signal for characterizing a pixel value, and obtaining a fingerprint image.

12. The method according to claim 10, wherein The pixel array includes: M*N pixel units; each pixel unit includes: a pixel electrode, a first switch corresponding to the pixel electrode, a storage capacitor, a second switch corresponding to the storage capacitor, a test capacitor, and a third switch corresponding to the test capacitor, and the storage capacitor is electrically connected to the test capacitor through the third switch; the number of the measurement modules is the same as the number of the pixel units; each test capacitor of each pixel unit is electrically connected to a measurement module respectively; The measurement module for controlling the capacitive fingerprint module converts the charge output by the pixel array into a digital signal for characterizing the pixel value to obtain a fingerprint image, including: Controlling each third switch in the capacitive fingerprint module to switch to the on state, and after maintaining the on state of the third switch for a third time period, controlling each of the third switches to switch to the off state; Controlling each measurement module in the capacitive fingerprint module to convert the charge in each test capacitor into a digital signal for characterizing the pixel value to obtain a fingerprint image.

13. The method according to claim 10, wherein The pixel array includes: M*N pixel units, N test capacitors respectively corresponding to N columns of pixel units, and N fourth switches respectively corresponding to the N test capacitors. Each pixel unit includes: a pixel electrode, a first switch corresponding to the pixel electrode, a storage capacitor, a second switch corresponding to the storage capacitor, and a third switch; the storage capacitors of the pixel units in the same column are respectively electrically connected to the test capacitor corresponding to this column through their respective third switches, and the test capacitor is connected to the ground through the fourth switch; the number of the measurement modules is the same as the number of columns of the pixel units, and each test capacitor is electrically connected to a measurement module respectively; The measurement module for controlling the capacitive fingerprint module converts the charge output by the pixel array into a digital signal for characterizing the pixel value to obtain a fingerprint image, including: Controlling each third switch of the pixel units in the i-th row of the capacitive fingerprint module to switch to the on state, and controlling each third switch of the remaining other row pixel units to switch to the off state. After maintaining the state of the third switch for a third time period, controlling each third switch of the pixel units in the i-th row to switch to the off state; Controlling the measurement module in the capacitive fingerprint module to convert the charge in each test capacitor into a digital signal for characterizing the pixel value of the i-th row of the fingerprint image, and controlling the fourth switch corresponding to each test capacitor to switch to the state of being short-circuited to the ground. i is incremented by 1 and returns to execute the step of controlling each third switch of the pixel units in the i-th row of the capacitive fingerprint module to switch to the on state until i = M, and the initial value of i is 1; After obtaining the pixel values of the M rows of the fingerprint image, generating the fingerprint image according to the pixel values of the M rows.

14. The method according to claim 10, characterized in that The pixel array includes: M*N pixel units, M test capacitors respectively corresponding to M rows of pixel units, and M fourth switches respectively corresponding to the M test capacitors. Each pixel unit includes: a pixel electrode, a first switch corresponding to the pixel electrode, a storage capacitor, a second switch corresponding to the storage capacitor, and a third switch. The storage capacitors of the pixel units in the same row are respectively electrically connected to the test capacitor corresponding to that row through their respective third switches, and the test capacitor is connected to the ground through the fourth switch. The number of the measurement modules is the same as the number of rows of the pixel units, and each test capacitor is electrically connected to a measurement module respectively; The measurement module for controlling the capacitive fingerprint module converts the charge output by the pixel array into a digital signal for characterizing the pixel value to obtain a fingerprint image, including: Controlling the third switches of the pixel units in the j-th column of the capacitive fingerprint module to be switched to the on state, and controlling the third switches of the pixel units in the remaining other columns to be switched to the off state. After the state of the third switch is maintained for a third time period, controlling the third switches of the pixel units in the j-th column to be switched to the off state; Controlling the measurement module in the capacitive fingerprint module to convert the charge in each test capacitor into a digital signal for characterizing the pixel value to obtain the pixel value of the j-th column of the fingerprint image, and controlling the fourth switches corresponding to the respective test capacitors to be switched to the short-circuit state to the ground. j is incremented by 1 and the step of controlling the third switches of the pixel units in the j-th column of the capacitive fingerprint module to be switched to the on state is returned and executed until j = N, and the initial value of j is 1; After obtaining the pixel values of N columns of the fingerprint image, generating the fingerprint image according to the pixel values of the N columns.

15. An electronic device, comprising: A memory, a processor, and a computer program stored on the memory, characterized by further comprising: a capacitive fingerprint module according to any one of claims 4-9, and the processor executes the computer program to implement the fingerprint image acquisition method according to any one of claims 10-14.

16. A computer-readable storage medium having computer programs / instructions stored thereon, characterized in that, When the computer program / instructions are executed by the processor, the fingerprint image acquisition method according to any one of claims 10-14 is implemented.

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