Ultrasonic fingerprint echo signal processing method and ultrasonic fingerprint pixel circuit

Abstract

The present specification provides a processing method of ultrasonic fingerprint echo signals and an ultrasonic fingerprint pixel circuit. Based on the method, when receiving echo signals, in a first time period, a first integrating circuit is connected by using a first switch and a second switch; and based on the echo signals, the output of the first integrating circuit is integrated and sampled to obtain a corresponding first intermediate signal; in a second time period, a second integrating circuit is connected by using the first switch and the second switch; and based on the echo signals, the output of the second integrating circuit is integrated and sampled to obtain a corresponding second intermediate signal; and a target signal meeting requirements is generated according to the first intermediate signal and the second intermediate signal. By switching the first integrating circuit and the second integrating circuit in the ultrasonic fingerprint pixel circuit, the utilization rate of the echo signals can be effectively improved, and in turn, clearer and higher-quality fingerprint data can be generated; meanwhile, the error influence of pixel mismatch on the fingerprint data can be reduced.

Description

Technical Field

[0001] This manual pertains to the field of fingerprint recognition technology, and particularly relates to methods for processing ultrasonic fingerprint echo signals and ultrasonic fingerprint pixel circuits. Background Technology

[0002] When performing ultrasonic fingerprint recognition based on existing ultrasonic fingerprint recognition technology, due to the influence of the working characteristics of ultrasonic signals, the difference between the ultrasonic echo signals of the corresponding fingerprint valleys and ridges obtained by directly processing the fingerprint pixel units is often relatively small and the signal-to-noise ratio is relatively low, resulting in poor quality of the final fingerprint data.

[0003] There is currently no effective solution to the above problems. Summary of the Invention

[0004] This specification provides a method for processing ultrasonic fingerprint echo signals and an ultrasonic fingerprint pixel circuit, which can effectively improve the utilization rate of echo signals and generate clearer, higher-quality fingerprint data; at the same time, it can also effectively reduce the error impact of pixel mismatch on fingerprint data.

[0005] This specification provides a method for processing ultrasonic fingerprint echo signals, applied to an ultrasonic fingerprint pixel circuit. The ultrasonic fingerprint pixel circuit includes at least a first integrating circuit and a second integrating circuit. The first integrating circuit includes at least a first operational amplifier whose first terminal is connected to the lower electrode of the piezoelectric sensor of the fingerprint pixel unit via a first switch. The second integrating circuit includes at least a second operational amplifier whose first terminal is connected to the lower electrode of the piezoelectric sensor of the fingerprint pixel unit via a second switch. The second terminals of the first and second operational amplifiers are connected to a preset reference power supply. The method includes:

[0006] When the fingerprint pixel unit receives an echo signal about the ultrasonic fingerprint data, it connects the first integrating circuit using the first and second switches within a first time period; and integrates and samples the output of the first integrating circuit based on the echo signal to obtain the corresponding first intermediate signal.

[0007] During the second time period, the second integrating circuit is connected using the first and second switches; and based on the echo signal, the output of the second integrating circuit is integrated and sampled to obtain the corresponding second intermediate signal.

[0008] Based on the first intermediate signal and the second intermediate signal, a target signal that meets the requirements is generated.

[0009] In one embodiment, the first time period is the time period from the peak to the trough of the echo signal; correspondingly, the second time period is the time period from the trough to the peak of the echo signal.

[0010] Alternatively, the first time period is the time period from the trough to the peak of the echo signal; correspondingly, the second time period is the time period from the peak to the trough of the echo signal.

[0011] In one embodiment, the method further includes:

[0012] Obtain relevant information about the coding signal;

[0013] Based on the relevant information of the coding signal, the relevant information of the echo signal is determined;

[0014] Based on the relevant information of the echo signal, the first time period and the second time period are determined.

[0015] In one embodiment, connecting the first integrating circuit using a first switch and a second switch includes: connecting the first integrating circuit by controlling the first switch to close and the second switch to open.

[0016] This specification also provides a method for processing ultrasonic fingerprint echo signals, applied to an ultrasonic fingerprint pixel circuit. The ultrasonic fingerprint pixel circuit includes at least: a first operational amplifier connected to a first fingerprint pixel unit, and a second operational amplifier connected to a second fingerprint pixel unit; the first terminals of the first and second operational amplifiers are respectively connected to the lower electrode plate of the piezoelectric sensor of the first fingerprint pixel unit via a first switch and a second switch, respectively; the first terminals of the first and second operational amplifiers are also respectively connected to the lower electrode plate of the piezoelectric sensor of the second fingerprint pixel unit via a third switch and a fourth switch, respectively; the lower electrode plate of the piezoelectric sensor of one of the first and second fingerprint pixel units is grounded. The method includes:

[0017] When the first trigger condition is met, the first fingerprint pixel unit switches into the running state by disconnecting the third and fourth switches;

[0018] During the first time period, the first integrating circuit is connected using the first switch and the second switch; and based on the received echo signal, the output of the first integrating circuit is integrated and sampled to obtain the corresponding first intermediate signal.

[0019] During the second time period, the second integrating circuit is connected using the first and second switches; and based on the received echo signal, the output of the second integrating circuit is integrated and sampled to obtain the corresponding second intermediate signal.

[0020] Based on the first intermediate signal and the second intermediate signal, a first target signal that meets the requirements is generated.

[0021] In one embodiment, the method further includes:

[0022] When the second trigger condition is met, the second fingerprint pixel unit switches into the running state by disconnecting the first and second switches.

[0023] During the third time period, the third integrator circuit is connected using the third and fourth switches; and based on the received echo signal, the output of the third integrator circuit is integrated and sampled to obtain the corresponding third intermediate signal.

[0024] During the fourth time period, the fourth integrator circuit is connected using the third and fourth switches; and based on the received echo signal, the output of the fourth integrator circuit is integrated and sampled to obtain the corresponding fourth intermediate signal.

[0025] Based on the third and fourth intermediate signals, a second target signal that meets the requirements is generated.

[0026] In one embodiment, the first fingerprint pixel unit and the second fingerprint pixel unit are fingerprint pixel units operating at different times in the fingerprint pixel unit array.

[0027] In one embodiment, the first fingerprint pixel unit and the second fingerprint pixel unit are fingerprint pixel units located on different rows in the fingerprint pixel unit array;

[0028] Alternatively, the first fingerprint pixel unit and the second fingerprint pixel unit may be fingerprint pixel units located in different columns of the fingerprint pixel unit array.

[0029] This specification also provides an ultrasonic fingerprint pixel circuit, comprising at least: a first operational amplifier connected to a first fingerprint pixel unit, and a second operational amplifier connected to a second fingerprint pixel unit; a first terminal of the first operational amplifier and a first terminal of the second operational amplifier are respectively connected to the lower electrode plate of the piezoelectric sensor of the first fingerprint pixel unit via a first switch and a second switch, respectively; the first terminals of the first operational amplifier and the second operational amplifier are also respectively connected to the lower electrode plate of the piezoelectric sensor of the second fingerprint pixel unit via a third switch and a fourth switch; the lower electrode plate of the piezoelectric sensor of one of the first and second fingerprint pixel units is grounded; the lower electrode plate of the piezoelectric sensor of the other of the first and second fingerprint pixel units is used to receive echo signals related to ultrasonic fingerprint data.

[0030] This specification also provides an ultrasonic fingerprint echo signal processing device applied to an ultrasonic fingerprint pixel circuit, wherein the ultrasonic fingerprint pixel circuit includes at least: a first integrating circuit and a second integrating circuit; the first integrating circuit includes at least a first operational amplifier whose first terminal is connected to the lower electrode of the piezoelectric sensor of the fingerprint pixel unit via a first switch, and the second integrating circuit includes at least a second operational amplifier whose first terminal is connected to the lower electrode of the piezoelectric sensor of the fingerprint pixel unit via a second switch; the second terminals of the first and second operational amplifiers are connected to a preset reference power supply, and the device includes:

[0031] The first processing module is used to connect the first integrating circuit using the first switch and the second switch within a first time period when the fingerprint pixel unit receives an echo signal about the ultrasonic fingerprint data; and to perform integral sampling on the output of the first integrating circuit based on the echo signal to obtain the corresponding first intermediate signal.

[0032] The second processing module is used to connect the second integrating circuit using the first and second switches during the second time period; and to perform integral sampling on the output of the second integrating circuit based on the echo signal to obtain the corresponding second intermediate signal.

[0033] The first generation module is used to generate a target signal that meets the requirements based on the first intermediate signal and the second intermediate signal.

[0034] This specification also provides an ultrasonic fingerprint echo signal processing device applied to an ultrasonic fingerprint pixel circuit, wherein the ultrasonic fingerprint pixel circuit includes at least: a first operational amplifier connected to a first fingerprint pixel unit, and a second operational amplifier connected to a second fingerprint pixel unit; the first terminals of the first and second operational amplifiers are respectively connected to the lower electrode plate of the piezoelectric sensor of the first fingerprint pixel unit through a first switch and a second switch, respectively; the first terminals of the first and second operational amplifiers are also respectively connected to the lower electrode plate of the piezoelectric sensor of the second fingerprint pixel unit through a third switch and a fourth switch, respectively; the lower electrode plate of the piezoelectric sensor of one of the first and second fingerprint pixel units is grounded, and the device includes:

[0035] The switching module is used to switch the first fingerprint pixel unit into the running state by disconnecting the third and fourth switches when the first trigger condition is met.

[0036] The third processing module is used to connect the first integrating circuit using the first switch and the second switch during the first time period; and to perform integration sampling on the output of the first integrating circuit based on the received echo signal to obtain the corresponding first intermediate signal.

[0037] The fourth processing module is used to connect the second integrating circuit using the first and second switches during the second time period; and to perform integral sampling on the output of the second integrating circuit based on the received echo signal to obtain the corresponding second intermediate signal.

[0038] The second generation module is used to generate a first target signal that meets the requirements based on the first intermediate signal and the second intermediate signal.

[0039] This specification also provides an electronic device, including a processor and a memory for storing processor-executable instructions, wherein the processor executes the instructions to implement the relevant steps of the ultrasonic fingerprint echo signal processing method.

[0040] This specification also provides a computer-readable storage medium having computer instructions stored thereon, which, when executed by a processor, implement the steps of the ultrasonic fingerprint echo signal processing method.

[0041] This specification also provides a computer program product comprising a computer program that, when executed by a processor, implements the steps of the ultrasonic fingerprint echo signal processing method.

[0042] Based on the ultrasonic fingerprint echo signal processing method and ultrasonic fingerprint pixel circuit provided in this specification, before specific implementation, a second operational amplifier can be introduced into the existing ultrasonic fingerprint pixel circuit containing a first operational amplifier. The first terminal (e.g., negative input terminal) of the first operational amplifier and the first terminal of the second operational amplifier are connected to the lower electrode plate of the piezoelectric sensor of the fingerprint pixel unit via a first switch and a second switch, respectively. The second terminal (e.g., positive input terminal) of the first operational amplifier and the second terminal of the second operational amplifier are connected to a preset reference power supply to construct the corresponding first and second integrating circuits. In specific implementation, when the fingerprint pixel unit receives an echo signal related to ultrasonic fingerprint data, during a first time period, the first and second switches can be used to switch and connect the first integrating circuit. Based on the echo signal during the first time period, the output of the first integrating circuit is integrated and sampled to obtain a corresponding first intermediate signal. During a second time period, the first and second switches are used to switch and connect the second integrating circuit. Based on the echo signal during the second time period, the output of the second integrating circuit is integrated and sampled to obtain a corresponding second intermediate signal. Finally, based on the first and second intermediate signals, a target signal meeting the requirements is generated. By using the ultrasonic fingerprint pixel circuit with the above structure, the utilization rate of the received echo signal can be effectively improved by switching between the first integrator circuit and the second integrator circuit to process the echo signal, thereby helping to improve the signal-to-noise ratio of the data and generate clearer and higher quality fingerprint data. At the same time, it can also effectively reduce the error impact of pixel mismatch in the circuit on the fingerprint data. Attached Figure Description

[0043] To more clearly illustrate the embodiments of this specification, the accompanying drawings used in the embodiments will be briefly introduced below. The drawings described below are only some embodiments recorded in this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is a flowchart illustrating a method for processing ultrasonic fingerprint echo signals according to an embodiment of this specification.

[0045] Figure 2 This is a schematic diagram of a fingerprint pixel unit in a scenario example, applying the ultrasonic fingerprint echo signal processing method provided in the embodiments of this specification.

[0046] Figure 3 This is a schematic diagram of the structural composition of an ultrasonic fingerprint pixel circuit provided in one embodiment of this specification;

[0047] Figure 4 This is a schematic diagram of one embodiment of the ultrasonic fingerprint echo signal processing method provided in the embodiments of this specification, applied in a scenario example.

[0048] Figure 5 This is a schematic diagram of one embodiment of the ultrasonic fingerprint echo signal processing method provided in the embodiments of this specification, applied in a scenario example.

[0049] Figure 6 This is a schematic diagram of one embodiment of the ultrasonic fingerprint echo signal processing method provided in the embodiments of this specification, applied in a scenario example.

[0050] Figure 7 This is a flowchart illustrating a method for processing ultrasonic fingerprint echo signals according to another embodiment of this specification;

[0051] Figure 8 This is a schematic diagram of the structural composition of an ultrasonic fingerprint pixel circuit provided in another embodiment of this specification;

[0052] Figure 9 This is a schematic diagram of one embodiment of the ultrasonic fingerprint echo signal processing method provided in the embodiments of this specification, applied in a scenario example.

[0053] Figure 10 This is a schematic diagram of the structural composition of an electronic device provided in one embodiment of this specification;

[0054] Figure 11This is a schematic diagram of the structural composition of an ultrasonic fingerprint echo signal processing device provided in one embodiment of this specification;

[0055] Figure 12 This is a schematic diagram of the structural composition of an ultrasonic fingerprint echo signal processing device provided in another embodiment of this specification. Detailed Implementation

[0056] To enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this specification, and not all embodiments. Based on the embodiments in this specification, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this specification.

[0057] It should be noted that the information and data related to users involved in the embodiments of this specification are all information and data authorized by the user or fully authorized by the relevant parties. Furthermore, the collection, storage, use, processing, transmission, provision, disclosure, and application of the relevant data all comply with relevant laws, regulations, and standards, and necessary confidentiality measures have been taken. They do not violate public order and good morals, and corresponding operation entry points are provided for users or relevant parties to choose to authorize or refuse.

[0058] It should also be noted that in the embodiments of this specification, certain software, components, models and other existing solutions in the industry may be mentioned. These should be regarded as exemplary and are only intended to illustrate the feasibility of implementing the technical solution of this application. However, they do not mean that the applicant has used or necessarily used the solution.

[0059] See Figure 1 As shown in the embodiments of this specification, a method for processing ultrasonic fingerprint echo signals is provided. Specifically, this method is applied to an ultrasonic fingerprint pixel circuit, wherein the ultrasonic fingerprint pixel circuit includes at least: a first integrating circuit and a second integrating circuit; the first integrating circuit includes at least a first operational amplifier whose first terminal is connected to the lower electrode of the piezoelectric sensor of the fingerprint pixel unit via a first switch; the second integrating circuit includes at least a second operational amplifier whose first terminal is connected to the lower electrode of the piezoelectric sensor of the fingerprint pixel unit via a second switch; the second terminals of the first and second operational amplifiers are connected to a preset reference power supply. In specific implementations, this method may include the following:

[0060] S101: When the fingerprint pixel unit receives an echo signal about the ultrasonic fingerprint data, during the first time period, the first integrating circuit is connected using the first switch and the second switch; and the output of the first integrating circuit is integrated and sampled based on the echo signal to obtain the corresponding first intermediate signal.

[0061] S102: During the second time period, the second integrating circuit is connected using the first and second switches; and the output of the second integrating circuit is integrated and sampled based on the echo signal to obtain the corresponding second intermediate signal;

[0062] S103: Generate a target signal that meets the requirements based on the first intermediate signal and the second intermediate signal.

[0063] Specifically, the aforementioned ultrasonic fingerprint pixel circuit can be understood as a circuit structure used in ultrasonic fingerprint devices to receive and process echo signals of ultrasonic fingerprint data received by the fingerprint pixel unit.

[0064] The aforementioned ultrasonic fingerprint device can specifically be an ultrasonic fingerprint access control system, an ultrasonic fingerprint scanner, or an ultrasonic fingerprint payment device, etc. It should be noted that the ultrasonic fingerprint devices listed above are merely illustrative. In actual implementation, depending on the specific application scenario and processing requirements, the aforementioned ultrasonic fingerprint pixel circuit can also be applied to other types of ultrasonic fingerprint devices. This specification does not limit its application in this regard.

[0065] The aforementioned echo signal carries fingerprint feature information (e.g., valley features, ridge features, etc. in fingerprints); correspondingly, by processing the echo signal, fingerprint data can be obtained for services such as fingerprint recognition, fingerprint verification, and fingerprint enrollment.

[0066] For details, please refer to Figure 2 As shown, the aforementioned ultrasonic fingerprint device can be provided with an active area (AA). Multiple fingerprint pixel units (pxl) can be arranged within this active area to form a fingerprint pixel unit array. For specific examples, see [link to documentation]. Figure 2 As shown, the recognition area can contain N A fingerprint pixel unit array consisting of M fingerprint pixel units. Each fingerprint pixel unit can be independent of each other.

[0067] Each of the aforementioned fingerprint pixel units can be connected to a corresponding ultrasonic fingerprint pixel circuit. (See also...) Figure 3As shown. Specifically, the aforementioned fingerprint pixel unit can be connected to the upper plate of a piezoelectric sensor (e.g., a piezoelectric thin film sensor, PVDF sensor). The lower plate of the piezoelectric sensor is connected to the first terminal (e.g., the negative input terminal) of a first operational amplifier (e.g., OP1) via a first switch (e.g., SW21) to form a first integrating circuit (which can be denoted as int1); simultaneously, the lower plate of the piezoelectric sensor is also connected to the first input terminal of a second operational amplifier (e.g., OP2) via a second switch (e.g., SW22) to form a second integrating circuit (which can be denoted as int2). The second input terminal (e.g., the positive input terminal) of the first operational amplifier and the second input terminal of the second operational amplifier can be connected to a preset reference power supply; wherein, the reference power supply is used to provide a reference voltage (e.g., VCM).

[0068] In addition, see Figure 3 As shown, a first parasitic capacitor (e.g., cfb11) and a switch sw11 are connected in parallel between the first input terminal and the output terminal (e.g., vout1) of the first operational amplifier; a second parasitic capacitor (e.g., cfb12) and a switch sw12 are connected in parallel between the first input terminal and the output terminal (e.g., vout2) of the second operational amplifier.

[0069] The first time period mentioned above can be specifically understood as the integration sampling time period involving the first integrating circuit. The second time period mentioned above can be specifically understood as the integration sampling time period involving the second integrating circuit.

[0070] Specifically, the first time period can be the time period from the peak to the trough of the echo signal; correspondingly, the second time period can be the time period from the trough to the peak of the echo signal; or, the first time period can be the time period from the trough to the peak of the echo signal; correspondingly, the second time period can be the time period from the peak to the trough of the echo signal.

[0071] See Figure 4 As shown, the combination of the first time period and the second time period can equal one complete cycle of the echo signal. S1 represents switches sw11 and sw12.

[0072] In practice, when a user presses their finger against the fingerprint pixel unit in the recognition area, the ultrasonic fingerprint device generates and emits an ultrasonic signal using an ultrasonic transmitting circuit based on a coding signal. This ultrasonic signal is reflected upon contact with the user's finger, forming a corresponding echo signal (e.g., VIN). The fingerprint pixel unit can receive this echo signal via the lower electrode of a connected piezoelectric sensor.

[0073] When the above echo signal is received, it will automatically detect whether it is the first time period or the second time period based on the signal change characteristics of the echo signal.

[0074] When the current time period is detected, the system triggers the first integration circuit, which connects the first operational amplifier, by controlling the first switch to close and the second switch to open within the first time period. Based on the echo signal within the first time period, the system integrates and samples the output of the first integration circuit to obtain the corresponding first intermediate signal.

[0075] When the current time period is detected to be the second time period, the system triggers the first switch to open and the second switch to close during the second time period, thereby connecting the second integrator circuit where the second operational amplifier is located. Based on the echo signal during the second time period, the system performs integration sampling on the output of the second integrator circuit to obtain the corresponding second intermediate signal.

[0076] Furthermore, by combining the first intermediate signal and the second intermediate signal, the error signal (e.g., mismatch voltage vos) formed at the output of the ultrasonic fingerprint pixel circuit due to pixel mismatch can be canceled out, resulting in an output signal (e.g., vout) with smaller error and higher accuracy, which can then be used as the target signal that meets the requirements.

[0077] The aforementioned target signal is specifically used for fingerprint-related data processing. For example, the target signal can be used to generate corresponding fingerprint images, to establish fingerprint feature templates, or to perform fingerprint matching, etc.

[0078] Based on the above embodiments, the ultrasonic fingerprint pixel circuit with the above structure automatically switches to use the first integrator circuit to process a portion of the echo signal within the first time period; simultaneously, it automatically switches to use the second integrator circuit to process a portion of the echo signal within the second time period. On the one hand, this effectively improves the utilization rate of the echo signal, thereby enhancing the signal-to-noise ratio during signal processing and obtaining clearer, higher-quality fingerprint data. On the other hand, it also effectively reduces the error impact of pixel mismatch on fingerprint data, improving fingerprint data accuracy.

[0079] In some embodiments, see Figure 4 As shown, the first time period can specifically be the time period from the peak to the trough of the echo signal; correspondingly, the second time period can specifically be the time period from the trough to the peak of the echo signal.

[0080] Alternatively, the first time period can specifically be the time period from the trough to the peak of the echo signal; correspondingly, the second time period can specifically be the time period from the peak to the trough of the echo signal.

[0081] In this way, the combination of the first time period and the second time period can be exactly equal to a complete cycle of the echo signal. Then, by using the first integrator circuit to integrate the echo signal based on the first time period and the second integrator circuit to integrate the echo signal based on the second time period, it is possible to achieve integration over the complete cycle of the echo signal from peak to trough and from trough to peak, thereby effectively improving the utilization rate of the echo signal.

[0082] In some embodiments, see Figure 5 As shown, in specific implementations, the method may also include the following:

[0083] S1: Obtain relevant information about the coding signal;

[0084] S2: Determine the relevant information of the echo signal based on the relevant information of the coding signal;

[0085] S3: Determine the first time period and the second time period based on the relevant information of the echo signal.

[0086] Specifically, the aforementioned coding signal (e.g., tx) can be understood as the source signal used by the ultrasonic transmitting circuit in the ultrasonic fingerprint device to generate and transmit ultrasonic waves.

[0087] The relevant information of the above-mentioned coding signal may include at least: the transmission time of the first signal in the coding signal, the signal period of the coding signal, etc.

[0088] See Figure 4 As shown, the above-mentioned coding signal and echo signal satisfy a certain correspondence in waveform change characteristics. Therefore, the relevant information of the echo signal can be determined based on the relevant information of the coding signal.

[0089] The relevant information of the echo signal may include at least: the reception time of the first signal in the echo signal, the signal period of the echo signal, the peak information of the echo signal, and the trough information of the echo signal.

[0090] Therefore, based on the relevant information of the echo signal, the first and second time periods that meet the requirements can be accurately determined.

[0091] In some embodiments, the first integrator circuit is connected by using the first switch and the second switch. In specific implementation, this may include connecting the first integrator circuit by controlling the first switch to close and the second switch to open.

[0092] Similarly, the above-mentioned use of the first switch and the second switch to connect the second integrating circuit can be implemented in a specific way, including: controlling the second switch to close and the first switch to open to connect the second integrating circuit.

[0093] Specifically, the first and second switches mentioned above can be connected to a logic control circuit. Accordingly, in practical implementation, the logic control circuit can generate control commands for the first and second switches to achieve connection of the first integrator circuit or the second integrator circuit.

[0094] In some embodiments, see Figure 4 As shown, the specific implementation of the method further includes the following: before the first time period and the second time period, during the integrator reset phase, in response to the reset trigger command, the first integrator circuit is connected using the first switch and the second switch; and the output of the first integrator circuit is processed based on a preset reference power supply to obtain a first initial signal; and the second integrator circuit is connected using the first switch and the second switch; and the output of the second integrator circuit is processed based on a preset reference power supply to obtain a second initial signal.

[0095] For specific implementation, please refer to Figure 6 As shown, the ultrasonic fingerprint pixel circuit can be equivalent to a CDS circuit. Specifically, the aforementioned CDS circuit (correlated double sampling circuit) can be understood as an electronic circuit used to suppress signal noise, primarily through a double sampling mechanism.

[0096] During the integrator reset phase, the fingerprint pixel unit has not yet received an echo signal. After connecting the first integrator circuit (int1), the output of the first integrator circuit can be sampled and reset using a first sampling signal (e.g., cds_sp1n) to obtain the corresponding first initial signal. After connecting the second integrator circuit (int2), the output of the second integrator circuit can be sampled and reset using a second sampling signal (e.g., cds_sp2p) to obtain the corresponding second initial signal.

[0097] Due to pixel mismatch, the first sampling signal can be represented as: vcm + vos1, and the second sampling signal can be represented as: vcm + vos2. Here, vcm is the reference voltage, and vos1 and vos2 are the first and second mismatch voltages caused by pixel mismatch, respectively. vos stands for offset voltage.

[0098] When the fingerprint pixel unit receives the echo signal (vin), the ultrasonic fingerprint pixel circuit enters the output sampling stage. At this time, during the first time period, the first integrating circuit can be connected; and based on the echo signal during the first time period, a third sampling signal (e.g., cds_sp1p) is used to integrate and sample the output of the first integrating circuit to obtain the corresponding first intermediate signal. During the second time period, the second integrating circuit can be connected; and based on the echo signal during the second time period, a fourth sampling signal (e.g., cds_sp2n) is used to integrate and sample the output of the second integrating circuit to obtain the corresponding second intermediate signal. Specifically, the first intermediate signal can be expressed as: vcm + vos1 + vs1, and the second intermediate signal can be expressed as: vcm + vos2 - vs2. Where vs1 is the first signal voltage formed by the echo signal during the first time period, and vs2 is the second signal voltage formed by the echo signal during the second time period. Typically, vs1 = vs2. vs stands for signal voltage.

[0099] Accordingly, the above-mentioned generation of a target signal that meets the requirements based on the first intermediate signal and the second intermediate signal may, in specific implementation, include: in the amplification stage, using the first initial signal, the second initial signal, the first intermediate signal, and the second intermediate signal in combination to generate a target signal that meets the requirements.

[0100] Specifically, during the amplification stage, the aforementioned CDS circuit can output the final result as the target signal according to the following formula:

[0101]

[0102] Wherein, cfb is the parasitic capacitance, equal to cfb11 and cfb12; cs (capacitor of sampling) is the capacitance value of the sampling capacitor of the circuit; voutp is the first signal output; and voutn is the second signal output.

[0103] Furthermore, if vs1=vs2=vs, .

[0104] Based on the above embodiments, by switching between the first and second integrator circuits, an equivalent CDS circuit is formed. This allows the differential input of the CDS circuit to specifically eliminate the mismatch voltage caused by pixel offset during signal processing, while simultaneously satisfying the coherent double sampling function. This effectively improves the utilization rate of the echo signal, thereby helping to improve the signal-to-noise ratio and generate clearer, higher-quality fingerprint data. Simultaneously, it effectively reduces the error impact of pixel offset on the fingerprint data. Since the target signal obtained using the above method has already eliminated the error impact of pixel offset, no additional chopper is required. Specifically, a chopper can be understood as a timing correction operation used to address pixel offset in the circuit.

[0105] Based on the above embodiments and the ultrasonic fingerprint echo signal processing method provided in this specification, before specific implementation, a second operational amplifier can be introduced into the existing ultrasonic fingerprint pixel circuit's first operational amplifier. The first terminals of the first and second operational amplifiers are connected to the lower electrode plate of the piezoelectric sensor of the fingerprint pixel unit via a first switch and a second switch, respectively. The second terminals of the first and second operational amplifiers are connected to a preset reference power supply to construct a corresponding first and second integrating circuit. In specific implementation, when the fingerprint pixel unit receives an echo signal related to ultrasonic fingerprint data, during a first time period, the first and second switches are used to switch and connect the first integrating circuit. Based on the echo signal, the output of the first integrating circuit is integrated and sampled to obtain a corresponding first intermediate signal. During a second time period, the first and second switches are used to switch and connect the second integrating circuit. Based on the echo signal, the output of the second integrating circuit is integrated and sampled to obtain a corresponding second intermediate signal. Finally, a target signal meeting the requirements is generated based on the first and second intermediate signals. By using the ultrasonic fingerprint pixel circuit with the above structure, the utilization rate of the received echo signal can be effectively improved by switching between the first integrator circuit and the second integrator circuit to process the echo signal, thereby helping to improve the signal-to-noise ratio and generate clearer and higher quality fingerprint data; at the same time, it can also effectively reduce the error impact of pixel mismatch on fingerprint data.

[0106] See Figure 7 As shown in the embodiments of this specification, another method for processing ultrasonic fingerprint echo signals is also provided. This method is specifically applied to an ultrasonic fingerprint pixel circuit, wherein the ultrasonic fingerprint pixel circuit includes at least: a first fingerprint pixel unit (e.g., row...). <n>The first operational amplifier connected to the second fingerprint pixel unit (e.g., row) and the second fingerprint pixel unit (e.g., row)<n+1> A second operational amplifier is connected to the first operational amplifier; the first terminals of the first and second operational amplifiers are respectively connected to the lower electrode plate of the piezoelectric sensor of the first fingerprint pixel unit through a first switch and a second switch, respectively. The first terminals of the first and second operational amplifiers are also respectively connected to the lower electrode plate of the piezoelectric sensor of the second fingerprint pixel unit through a third switch and a fourth switch, respectively. The lower electrode plate of the piezoelectric sensor of one of the fingerprint pixel units (the first or the second fingerprint pixel unit) is grounded, and the lower electrode plate of the piezoelectric sensor of the remaining fingerprint pixel unit is used to receive the echo signal. In specific implementations of the above method, the following may be included:

[0107] S701: When the first trigger condition is met, the first fingerprint pixel unit switches to the running state by disconnecting the third switch and the fourth switch;

[0108] S702: During the first time period, the first integrating circuit is connected using the first switch and the second switch; and the output of the first integrating circuit is integrated and sampled based on the received echo signal to obtain the corresponding first intermediate signal.

[0109] S703: During the second time period, the second integrating circuit is connected using the first and second switches; and the output of the second integrating circuit is integrated and sampled based on the received echo signal to obtain the corresponding second intermediate signal.

[0110] S704: Generate a first target signal that meets the requirements based on the first intermediate signal and the second intermediate signal.

[0111] Among them, see Figure 8 As shown, the ultrasonic fingerprint pixel circuit described above includes at least two different fingerprint pixel units and related circuitry.

[0112] The two different fingerprint pixel units mentioned above can be referred to as the first fingerprint pixel unit and the second fingerprint pixel unit, respectively. Specifically, the first fingerprint pixel unit and the second fingerprint pixel unit are fingerprint pixel units that operate at different times in the fingerprint pixel unit array. That is, the first fingerprint pixel unit and the second fingerprint pixel unit are fingerprint pixel units that do not need to operate simultaneously.

[0113] In addition, the second terminals of the first operational amplifier and the second operational amplifier are also connected to a preset reference power supply.

[0114] Specifically, the lower electrode of the piezoelectric sensor in one of the first and second fingerprint pixel units is grounded, while the lower electrode of the piezoelectric sensor in the remaining fingerprint pixel unit is used to receive the echo signal. Thus, the electrical signal generated when the echo signal reaches the piezoelectric layer of the piezoelectric sensor can be read out by the lower electrode and transmitted to the circuit for further processing.

[0115] In specific implementation, when a first enable signal (e.g., signal EN1) is received for the first fingerprint pixel unit, it is determined that the first trigger condition is met. At this time, the first fingerprint pixel unit can be switched into the running state by disconnecting the third switch (e.g., s31d) and the fourth switch (e.g., s32d); at the same time, the second fingerprint pixel unit is switched into the stopped state.

[0116] In this case, the echo signal of the received ultrasonic fingerprint data is mainly processed by the first fingerprint pixel unit that is in operation.

[0117] Similarly, when a second enable signal (e.g., signal EN2) is received for the second fingerprint pixel unit, it is determined that the second trigger condition is met. At this time, the second fingerprint pixel unit can be switched into the running state by disconnecting the first switch (e.g., s21d) and the second switch (e.g., s22d); at the same time, the first fingerprint pixel unit is switched into the stopped state.

[0118] In this case, the echo signal of the received ultrasonic fingerprint data is mainly processed by the second fingerprint pixel unit that is in operation.

[0119] When the third and fourth switches are disconnected, the first switch and the first operational amplifier connected to the lower electrode plate of the piezoelectric sensor of the first fingerprint pixel unit can form a first integrating circuit; the second switch and the second operational amplifier connected to the lower electrode plate of the piezoelectric sensor of the first fingerprint pixel unit can form a second integrating circuit.

[0120] Furthermore, the first and second integrating circuits described above can be used to detect and distinguish between a first time period and a second time period. During the first time period, the first integrating circuit is connected using the first and second switches. Based on the received echo signal, the output of the first integrating circuit is integrated and sampled to obtain a corresponding first intermediate signal. During the second time period, the second integrating circuit is connected using the first and second switches. Based on the received echo signal, the output of the second integrating circuit is integrated and sampled to obtain a corresponding second intermediate signal. Based on the first and second intermediate signals, a first target signal that meets the requirements is generated.

[0121] Wherein, the first time period is the time period from the peak to the trough of the echo signal; correspondingly, the second time period is the time period from the trough to the peak of the echo signal; or, the first time period is the time period from the trough to the peak of the echo signal; correspondingly, the second time period is the time period from the peak to the trough of the echo signal.

[0122] Similarly, when the first and second switches are disconnected, the third switch and the first operational amplifier connected to the lower electrode plate of the piezoelectric sensor of the second fingerprint pixel unit can form a third integrating circuit; the fourth switch and the second operational amplifier connected to the lower electrode plate of the piezoelectric sensor of the second fingerprint pixel unit can form a fourth integrating circuit.

[0123] Furthermore, the aforementioned third and fourth integrator circuits can be used to detect and distinguish between the third and fourth time periods. During the third time period, the third integrator circuit is connected using the third and fourth switches; and the output of the third integrator circuit is integrated and sampled based on the received echo signal to obtain the corresponding third intermediate signal. During the fourth time period, the fourth integrator circuit is connected using the third and fourth switches; and the output of the fourth integrator circuit is integrated and sampled based on the received echo signal to obtain the corresponding fourth intermediate signal. Based on the third and fourth intermediate signals, a second target signal that meets the requirements is generated.

[0124] Wherein, the third time period is the time period from the peak to the trough of the echo signal; correspondingly, the fourth time period is the time period from the trough to the peak of the echo signal; or, the third time period is the time period from the trough to the peak of the echo signal; correspondingly, the fourth time period is the time period from the peak to the trough of the echo signal.

[0125] For the specific signal timing diagram during operation, please refer to [the relevant documentation / reference]. Figure 9 As shown in the figure. Specifically, sw1 can be switch sw11 or switch s12.

[0126] Based on the above embodiments, by combining two fingerprint pixel units that do not operate simultaneously, and related circuits, a first integrating circuit and a second integrating circuit for the first fingerprint pixel unit, and a third integrating circuit and a fourth integrating circuit for the second fingerprint pixel unit, can be constructed without introducing additional operational amplifiers and related circuits. Furthermore, by switching and utilizing the aforementioned first integrating circuit, second integrating circuit, third integrating circuit, and fourth integrating circuit, the fingerprint echo signals for the first fingerprint pixel unit and the second fingerprint pixel unit can be processed respectively, resulting in clearer and higher-quality fingerprint data. Simultaneously, since no additional operational amplifiers and related circuits are required, circuit area overhead can be effectively reduced.

[0127] In some embodiments, the method may further include the following:

[0128] S1: When the second trigger condition is met, the second fingerprint pixel unit switches into the running state by disconnecting the first switch and the second switch;

[0129] S2: During the third time period, the third integrator circuit is connected using the third and fourth switches; and the output of the third integrator circuit is integrated and sampled based on the received echo signal to obtain the corresponding third intermediate signal.

[0130] S3: During the fourth time period, the fourth integrating circuit is connected using the third and fourth switches; and the output of the fourth integrating circuit is integrated and sampled based on the received echo signal to obtain the corresponding fourth intermediate signal.

[0131] S4: Generate a second target signal that meets the requirements based on the third and fourth intermediate signals.

[0132] In some embodiments, the first fingerprint pixel unit and the second fingerprint pixel unit may specifically be fingerprint pixel units operating at different times in a fingerprint pixel unit array.

[0133] In some embodiments, the first fingerprint pixel unit and the second fingerprint pixel unit may specifically be fingerprint pixel units located on different rows in the fingerprint pixel unit array;

[0134] Alternatively, the first fingerprint pixel unit and the second fingerprint pixel unit can specifically be fingerprint pixel units located in different columns of the fingerprint pixel unit array.

[0135] Specifically, the first fingerprint pixel unit and the second fingerprint pixel unit can be two adjacent fingerprint pixel units in the fingerprint pixel unit array, or they can be two non-adjacent fingerprint pixel units in the fingerprint pixel unit array.

[0136] As can be seen from the above, the ultrasonic fingerprint echo signal processing method provided in the embodiments of this specification can make full use of two fingerprint pixel units that do not operate simultaneously, as well as related circuit structures. Without adding new operational amplifiers and related circuits, by constructing and switching the first, second, third, and fourth integrating circuits to process the received echo signal, it can effectively improve the utilization rate of the echo signal while satisfying the functional application of a single fingerprint pixel unit, thereby helping to improve the signal-to-noise ratio and generate clearer, higher-quality fingerprint data. Furthermore, it can effectively reduce the error impact of pixel mismatch on fingerprint data. In addition, it can reduce circuit area overhead and lower the overall implementation cost.

[0137] See Figure 3 As shown, this specification also provides an ultrasonic fingerprint pixel circuit, which may include at least: a first integrating circuit and a second integrating circuit; the first integrating circuit includes at least a first operational amplifier whose first terminal is connected to the lower electrode plate of the piezoelectric sensor of the fingerprint pixel unit through a first switch, and the second integrating circuit includes at least a second operational amplifier whose first terminal is connected to the lower electrode plate of the piezoelectric sensor of the fingerprint pixel unit through a second switch; the second terminals of the first operational amplifier and the second operational amplifier are connected to a preset reference power supply.

[0138] See Figure 8 As shown in the specification, this specification also provides an ultrasonic fingerprint pixel circuit, which may include at least: a first operational amplifier connected to a first fingerprint pixel unit, and a second operational amplifier connected to a second fingerprint pixel unit; the first terminals of the first operational amplifier and the second operational amplifier are respectively connected to the lower electrode plate of the piezoelectric sensor of the first fingerprint pixel unit through a first switch and a second switch, respectively; the first terminals of the first operational amplifier and the second operational amplifier are also respectively connected to the lower electrode plate of the piezoelectric sensor of the second fingerprint pixel unit through a third switch and a fourth switch, respectively; the lower electrode plate of the piezoelectric sensor of one of the first and second fingerprint pixel units is grounded; the lower electrode plate of the piezoelectric sensor of the other of the first and second fingerprint pixel units is used to receive echo signals related to ultrasonic fingerprint data.

[0139] The second terminals of the first operational amplifier and the second operational amplifier are also connected to a preset reference power supply.

[0140] This specification provides an electronic device through its embodiments. (See attached document.) Figure 10 As shown. The electronic device includes a network communication port 1001, a processor 1002, and a memory 1003. These structures are connected by internal cables so that they can perform specific data interaction.

[0141] Specifically, the network communication port 1001 can be used to detect and receive echo signals.

[0142] Specifically, the processor 1002 can be used to, when the fingerprint pixel unit receives an echo signal about ultrasonic fingerprint data, connect a first integrating circuit using a first switch and a second switch during a first time period; and perform integral sampling on the output of the first integrating circuit based on the echo signal to obtain a corresponding first intermediate signal; connect a second integrating circuit using the first switch and a second switch during a second time period; and perform integral sampling on the output of the second integrating circuit based on the echo signal to obtain a corresponding second intermediate signal; and generate a target signal that meets the requirements based on the first intermediate signal and the second intermediate signal.

[0143] The memory 1003 can be used to store the corresponding instruction program and related intermediate data.

[0144] Based on the above method, the relevant structural performance of electronic devices can be effectively utilized to improve the data processing speed of electronic devices and efficiently realize the processing of ultrasonic fingerprint echo signals.

[0145] In this embodiment, the network communication port 1001 can be a virtual port bound to different communication protocols, thereby enabling the sending or receiving of different data. For example, the network communication port can be a port responsible for web data communication, a port responsible for FTP data communication, or a port responsible for email data communication. Furthermore, the network communication port can also be a physical communication interface or communication chip. For example, it can be a wireless mobile network communication chip, such as GSM or CDMA; it can also be a Wi-Fi chip; or it can be a Bluetooth chip.

[0146] In this embodiment, the processor 1002 can be implemented in any suitable manner. For example, the processor can take the form of a microprocessor or processor and a computer-readable medium storing computer-readable program code (e.g., software or firmware) executable by the (micro)processor, logic gates, switches, application-specific integrated circuits (ASICs), programmable logic controllers, and embedded microcontrollers, etc. This specification is not limiting.

[0147] In this embodiment, the memory 1003 may include multiple layers. In a digital system, anything that can store binary data can be a memory. In an integrated circuit, a circuit with storage function but no physical form is also called a memory, such as RAM, FIFO, etc. In a system, a storage device with a physical form is also called a memory, such as a memory stick, TF card, etc.

[0148] This specification also provides a computer-readable storage medium based on the above-described ultrasonic fingerprint echo signal processing method. The computer-readable storage medium stores computer program instructions that, when executed, implement the following: when a fingerprint pixel unit receives an echo signal related to ultrasonic fingerprint data, during a first time period, a first integrating circuit is connected using a first switch and a second switch; and based on the echo signal, the output of the first integrating circuit is integrated and sampled to obtain a corresponding first intermediate signal; during a second time period, a second integrating circuit is connected using the first switch and the second switch; and based on the echo signal, the output of the second integrating circuit is integrated and sampled to obtain a corresponding second intermediate signal; and a target signal meeting the requirements is generated based on the first and second intermediate signals.

[0149] This specification also provides another computer-readable storage medium based on the above-described ultrasonic fingerprint echo signal processing method. The computer-readable storage medium stores computer program instructions that, when executed, implement the following: when a first trigger condition is met, by disconnecting the third and fourth switches, the first fingerprint pixel unit switches to an operating state; during a first time period, using the first and second switches, the first integrating circuit is connected; and based on the received echo signal, the output of the first integrating circuit is integrated and sampled to obtain a corresponding first intermediate signal; during a second time period, using the first and second switches, the second integrating circuit is connected; and based on the received echo signal, the output of the second integrating circuit is integrated and sampled to obtain a corresponding second intermediate signal; and based on the first and second intermediate signals, a first target signal meeting the requirements is generated.

[0150] In this embodiment, the storage medium includes, but is not limited to, Random Access Memory (RAM), Read-Only Memory (ROM), Cache, Hard Disk Drive (HDD), or Memory Card. The memory can be used to store computer program instructions. The network communication unit can be an interface configured according to standards specified in the communication protocol for network connection communication.

[0151] In this embodiment, the specific functions and effects implemented by the program instructions stored in the computer-readable storage medium can be explained in comparison with other embodiments, and will not be repeated here.

[0152] This specification also provides a computer program product, comprising at least a computer program, which, when executed by a processor, implements the following method steps: when a fingerprint pixel unit receives an echo signal relating to ultrasonic fingerprint data, during a first time period, a first integrating circuit is connected using a first switch and a second switch; and based on the echo signal, the output of the first integrating circuit is integrated and sampled to obtain a corresponding first intermediate signal; during a second time period, a second integrating circuit is connected using the first switch and the second switch; and based on the echo signal, the output of the second integrating circuit is integrated and sampled to obtain a corresponding second intermediate signal; and a target signal meeting the requirements is generated based on the first intermediate signal and the second intermediate signal.

[0153] This specification also provides another computer program product, which includes at least a computer program that, when executed by a processor, implements the following method steps: when a first trigger condition is met, the first fingerprint pixel unit switches to the running state by disconnecting the third and fourth switches; during a first time period, the first integrating circuit is connected using the first and second switches; and the output of the first integrating circuit is integrated and sampled based on the received echo signal to obtain a corresponding first intermediate signal; during a second time period, the second integrating circuit is connected using the first and second switches; and the output of the second integrating circuit is integrated and sampled based on the received echo signal to obtain a corresponding second intermediate signal; and a first target signal that meets the requirements is generated based on the first and second intermediate signals.

[0154] See Figure 11 As shown in the embodiments of this specification, an ultrasonic fingerprint echo signal processing device is also provided, applied to an ultrasonic fingerprint pixel circuit. The ultrasonic fingerprint pixel circuit includes at least: a first integrating circuit and a second integrating circuit; the first integrating circuit includes at least a first operational amplifier whose first terminal is connected to the lower electrode of the piezoelectric sensor of the fingerprint pixel unit via a first switch; the second integrating circuit includes at least a second operational amplifier whose first terminal is connected to the lower electrode of the piezoelectric sensor of the fingerprint pixel unit via a second switch; the second terminals of the first and second operational amplifiers are connected to a preset reference power supply. The device may specifically include the following structural modules:

[0155] The first processing module 1101 is specifically used to connect the first integrating circuit using the first switch and the second switch within a first time period when the fingerprint pixel unit receives the echo signal of the ultrasonic fingerprint data; and to perform integral sampling on the output of the first integrating circuit based on the echo signal to obtain the corresponding first intermediate signal.

[0156] The second processing module 1102 can be used to connect the second integrating circuit using the first switch and the second switch during the second time period; and to perform integral sampling on the output of the second integrating circuit based on the echo signal to obtain the corresponding second intermediate signal.

[0157] The first generation module 1103 can be used to generate a target signal that meets the requirements based on the first intermediate signal and the second intermediate signal.

[0158] In some embodiments, the first time period is the time period from the peak to the trough of the echo signal; correspondingly, the second time period is the time period from the trough to the peak of the echo signal.

[0159] Alternatively, the first time period is the time period from the trough to the peak of the echo signal; correspondingly, the second time period is the time period from the peak to the trough of the echo signal.

[0160] In some embodiments, the device may also be used to: acquire relevant information of the coding signal; determine relevant information of the echo signal based on the relevant information of the coding signal; and determine a first time period and a second time period based on the relevant information of the echo signal.

[0161] In some embodiments, when the first processing module 1101 is specifically implemented, the first integrating circuit can be connected by using the first switch and the second switch in the following manner: by controlling the first switch to close and the second switch to open, the first integrating circuit is connected.

[0162] See Figure 12 As shown in the embodiments of this specification, another ultrasonic fingerprint echo signal processing device is provided, applied to an ultrasonic fingerprint pixel circuit. The ultrasonic fingerprint pixel circuit includes at least: a first operational amplifier connected to a first fingerprint pixel unit, and a second operational amplifier connected to a second fingerprint pixel unit; the first terminals of the first and second operational amplifiers are respectively connected to the lower electrode plate of the piezoelectric sensor of the first fingerprint pixel unit via a first switch and a second switch, respectively; the first terminals of the first and second operational amplifiers are also respectively connected to the lower electrode plate of the piezoelectric sensor of the second fingerprint pixel unit via a third switch and a fourth switch, respectively; the lower electrode plate of the piezoelectric sensor of one of the first and second fingerprint pixel units is grounded. The device may specifically include the following structural modules:

[0163] The switching module 1201 can be used to switch the first fingerprint pixel unit into the running state by disconnecting the third switch and the fourth switch when the first trigger condition is met.

[0164] The third processing module 1202 can be used to connect the first integrating circuit using the first switch and the second switch during the first time period; and to perform integration sampling on the output of the first integrating circuit based on the received echo signal to obtain the corresponding first intermediate signal.

[0165] The fourth processing module 1203 can be used to connect the second integrating circuit using the first and second switches during the second time period; and to perform integral sampling on the output of the second integrating circuit based on the received echo signal to obtain the corresponding second intermediate signal.

[0166] The second generation module 1204 can be used to generate a first target signal that meets the requirements based on the first intermediate signal and the second intermediate signal.

[0167] In some embodiments, the device may further be used to: when a second trigger condition is met, disconnect the first and second switches to allow the second fingerprint pixel unit to switch into an operating state; during a third time period, connect the third integrating circuit using the third and fourth switches; and perform integral sampling on the output of the third integrating circuit based on the received echo signal to obtain a corresponding third intermediate signal; during a fourth time period, connect the fourth integrating circuit using the third and fourth switches; and perform integral sampling on the output of the fourth integrating circuit based on the received echo signal to obtain a corresponding fourth intermediate signal; and generate a second target signal that meets the requirements based on the third and fourth intermediate signals.

[0168] In some embodiments, the first fingerprint pixel unit and the second fingerprint pixel unit are fingerprint pixel units operating at different times in a fingerprint pixel unit array.

[0169] In some embodiments, the first fingerprint pixel unit and the second fingerprint pixel unit are fingerprint pixel units located on different rows in the fingerprint pixel unit array;

[0170] Alternatively, the first fingerprint pixel unit and the second fingerprint pixel unit may be fingerprint pixel units located in different columns of the fingerprint pixel unit array.

[0171] It should be noted that the units, devices, or modules described in the above embodiments can be implemented by computer chips or physical entities, or by products with certain functions. For ease of description, the above devices are described by dividing them into various modules according to their functions. Of course, in implementing this specification, the functions of each module can be implemented in one or more software and / or hardware, or the module that implements the same function can be implemented by a combination of multiple sub-modules or sub-units, etc. The device embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and there may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection between the devices or units shown or discussed can be through some interfaces, and the indirect coupling or communication connection between devices or units can be electrical, mechanical, or other forms.

[0172] As can be seen from the above, the ultrasonic fingerprint echo signal processing device provided in the embodiments of this specification can make full use of the relevant structures of the ultrasonic fingerprint pixel circuit described above. By switching between the first integrator circuit and the second integrator circuit to process the received echo signal, the utilization rate of the echo signal can be effectively improved, thereby helping to improve the signal-to-noise ratio and generate clearer and higher quality fingerprint data. At the same time, it can also effectively reduce the error impact of pixel mismatch on fingerprint data.

[0173] While this specification provides the steps of operation for the methods described in the embodiments or flowcharts, more or fewer steps may be included based on conventional or non-inventive means. The order of steps listed in the embodiments is merely one possible order of execution among many steps and does not represent the only possible order. In actual device or client product execution, the methods may be executed sequentially or in parallel as shown in the embodiments or drawings (e.g., in a parallel processor or multi-threaded processing environment, or even a distributed data processing environment). The terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, product, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, product, or apparatus. Without further limitations, the presence of other identical or equivalent elements in a process, method, product, or apparatus that includes said elements is not excluded. The terms "first," "second," etc., are used to denote names and do not indicate any particular order.

[0174] Those skilled in the art will also know that, besides implementing the controller using purely computer-readable program code, the same functions can be achieved by logically programming the method steps, making the controller function as logic gates, switches, application-specific integrated circuits (ASICs), programmable logic controllers (PLCs), and embedded microcontrollers. Therefore, such a controller can be considered a hardware component, and the devices within it used to implement various functions can also be considered structures within that hardware component. Alternatively, the devices used to implement various functions can be considered as both software modules implementing the method and structures within a hardware component.

[0175] This specification can be described in the general context of computer-executable instructions that are executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, classes, etc., that perform a specific task or implement a specific abstract data type. This specification can also be practiced in distributed computing environments, where tasks are performed by remote processing devices connected via a communication network. In distributed computing environments, program modules can reside in local and remote computer-readable storage media, including storage devices.

[0176] As can be seen from the above description of the embodiments, those skilled in the art can clearly understand that this specification can be implemented by means of software plus necessary general-purpose hardware platforms. Based on this understanding, the technical solutions of this specification can essentially be embodied in the form of a software product. This computer software product can be stored in a storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, mobile terminal, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments of this specification.

[0177] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on its differences from other embodiments. This specification can be used in numerous general-purpose or special-purpose computer system environments or configurations. Examples include: personal computers, server computers, handheld or portable devices, tablet devices, multiprocessor systems, microprocessor-based systems, set-top boxes, programmable electronic devices, network PCs, minicomputers, mainframe computers, and distributed computing environments including any of the above systems or devices, etc.

[0178] Although this specification has been described by way of examples, those skilled in the art will recognize that many variations and modifications are possible without departing from the spirit of this specification, and it is intended that the appended claims cover such variations and modifications without departing from the spirit of this specification.< / n>

Claims

1. A method for processing ultrasonic fingerprint echo signals, characterized in that, An ultrasonic fingerprint pixel circuit is applied, wherein the ultrasonic fingerprint pixel circuit includes at least: a first integrating circuit and a second integrating circuit; the first integrating circuit includes at least a first operational amplifier whose first terminal is connected to the lower electrode of the piezoelectric sensor of the fingerprint pixel unit via a first switch, and the second integrating circuit includes at least a second operational amplifier whose first terminal is connected to the lower electrode of the piezoelectric sensor of the fingerprint pixel unit via a second switch; the second terminals of the first and second operational amplifiers are connected to a preset reference power supply, and the method includes: When the fingerprint pixel unit receives an echo signal about the ultrasonic fingerprint data, it connects the first integrating circuit using the first and second switches within a first time period; and integrates and samples the output of the first integrating circuit based on the echo signal to obtain the corresponding first intermediate signal. During the second time period, the second integrating circuit is connected using the first and second switches; and based on the echo signal, the output of the second integrating circuit is integrated and sampled to obtain the corresponding second intermediate signal. Based on the first intermediate signal and the second intermediate signal, a target signal that meets the requirements is generated.

2. The method according to claim 1, characterized in that, The first time period is the time from the peak to the trough of the echo signal; correspondingly, the second time period is the time from the trough to the peak of the echo signal. Alternatively, the first time period is the time period from the trough to the peak of the echo signal; correspondingly, the second time period is the time period from the peak to the trough of the echo signal.

3. The method according to claim 2, characterized in that, The method further includes: Obtain relevant information about the coding signal; Based on the relevant information of the coding signal, the relevant information of the echo signal is determined; Based on the relevant information of the echo signal, the first time period and the second time period are determined.

4. The method according to claim 1, characterized in that, Connecting the first integrating circuit using a first switch and a second switch includes: connecting the first integrating circuit by controlling the first switch to close and the second switch to open.

5. A method for processing ultrasonic fingerprint echo signals, characterized in that, An ultrasonic fingerprint pixel circuit is applied, wherein the ultrasonic fingerprint pixel circuit includes at least: a first operational amplifier connected to a first fingerprint pixel unit, and a second operational amplifier connected to a second fingerprint pixel unit; a first terminal of the first operational amplifier and a first terminal of the second operational amplifier are respectively connected to the lower electrode plate of the piezoelectric sensor of the first fingerprint pixel unit through a first switch and a second switch, respectively; the first terminals of the first operational amplifier and the second operational amplifier are also respectively connected to the lower electrode plate of the piezoelectric sensor of the second fingerprint pixel unit through a third switch and a fourth switch, respectively; the lower electrode plate of the piezoelectric sensor of one of the first and second fingerprint pixel units is grounded, and the method includes: When the first trigger condition is met, the first fingerprint pixel unit switches into the running state by disconnecting the third and fourth switches; During the first time period, the first integrating circuit is connected using the first switch and the second switch; and based on the received echo signal, the output of the first integrating circuit is integrated and sampled to obtain the corresponding first intermediate signal. During the second time period, the second integrating circuit is connected using the first and second switches; and based on the received echo signal, the output of the second integrating circuit is integrated and sampled to obtain the corresponding second intermediate signal. Based on the first intermediate signal and the second intermediate signal, a first target signal that meets the requirements is generated.

6. The method according to claim 5, characterized in that, The method further includes: When the second trigger condition is met, the second fingerprint pixel unit switches into the running state by disconnecting the first and second switches. During the third time period, the third integrator circuit is connected using the third and fourth switches; and based on the received echo signal, the output of the third integrator circuit is integrated and sampled to obtain the corresponding third intermediate signal. During the fourth time period, the fourth integrating circuit is connected using the third and fourth switches; and based on the received echo signal, the output of the fourth integrating circuit is integrated and sampled to obtain the corresponding fourth intermediate signal. Based on the third and fourth intermediate signals, a second target signal that meets the requirements is generated.

7. The method according to claim 5, characterized in that, The first fingerprint pixel unit and the second fingerprint pixel unit are fingerprint pixel units that operate at different times in the fingerprint pixel unit array.

8. The method according to claim 7, characterized in that, The first fingerprint pixel unit and the second fingerprint pixel unit are fingerprint pixel units located in different rows in the fingerprint pixel unit array; Alternatively, the first fingerprint pixel unit and the second fingerprint pixel unit may be fingerprint pixel units located in different columns of the fingerprint pixel unit array.

9. An ultrasonic fingerprint pixel circuit, characterized in that, It includes at least: a first operational amplifier connected to the first fingerprint pixel unit, and a second operational amplifier connected to the second fingerprint pixel unit; The first terminal of the first operational amplifier and the first terminal of the second operational amplifier are respectively connected to the lower electrode plate of the piezoelectric sensor of the first fingerprint pixel unit through the first switch and the second switch. The first terminal of the first operational amplifier and the first terminal of the second operational amplifier are also respectively connected to the lower electrode plate of the piezoelectric sensor of the second fingerprint pixel unit through the third switch and the fourth switch. The lower electrode plate of the piezoelectric sensor of one of the first fingerprint pixel units and the second fingerprint pixel unit is grounded. The lower electrode plate of the piezoelectric sensor of the other one of the first fingerprint pixel units and the second fingerprint pixel unit is used to receive the echo signal of the ultrasonic fingerprint data.

10. A processing device for ultrasonic fingerprint echo signals, characterized in that, An ultrasonic fingerprint pixel circuit is applied to an ultrasonic fingerprint pixel circuit, wherein the ultrasonic fingerprint pixel circuit includes at least: a first integrating circuit and a second integrating circuit; the first integrating circuit includes at least a first operational amplifier whose first terminal is connected to the lower electrode of the piezoelectric sensor of the fingerprint pixel unit via a first switch, and the second integrating circuit includes at least a second operational amplifier whose first terminal is connected to the lower electrode of the piezoelectric sensor of the fingerprint pixel unit via a second switch; the second terminals of the first and second operational amplifiers are connected to a preset reference power supply, and the device includes: The first processing module is used to connect the first integrating circuit using the first switch and the second switch within a first time period when the fingerprint pixel unit receives an echo signal about the ultrasonic fingerprint data; and to perform integral sampling on the output of the first integrating circuit based on the echo signal to obtain the corresponding first intermediate signal. The second processing module is used to connect the second integrating circuit using the first and second switches during the second time period; and to perform integral sampling on the output of the second integrating circuit based on the echo signal to obtain the corresponding second intermediate signal. The first generation module is used to generate a target signal that meets the requirements based on the first intermediate signal and the second intermediate signal.

11. A processing device for ultrasonic fingerprint echo signals, characterized in that, An ultrasonic fingerprint pixel circuit is applied, wherein the ultrasonic fingerprint pixel circuit includes at least: a first operational amplifier connected to a first fingerprint pixel unit, and a second operational amplifier connected to a second fingerprint pixel unit; the first terminals of the first and second operational amplifiers are respectively connected to the lower electrode plate of the piezoelectric sensor of the first fingerprint pixel unit through a first switch and a second switch, respectively; the first terminals of the first and second operational amplifiers are also respectively connected to the lower electrode plate of the piezoelectric sensor of the second fingerprint pixel unit through a third switch and a fourth switch, respectively; the lower electrode plate of the piezoelectric sensor of one of the first and second fingerprint pixel units is grounded, and the device includes: The switching module is used to switch the first fingerprint pixel unit into the running state by disconnecting the third and fourth switches when the first trigger condition is met. The third processing module is used to connect the first integrating circuit using the first switch and the second switch during the first time period; and to perform integration sampling on the output of the first integrating circuit based on the received echo signal to obtain the corresponding first intermediate signal. The fourth processing module is used to connect the second integrating circuit using the first and second switches during the second time period; and to perform integral sampling on the output of the second integrating circuit based on the received echo signal to obtain the corresponding second intermediate signal. The second generation module is used to generate a first target signal that meets the requirements based on the first intermediate signal and the second intermediate signal.

12. An electronic device, characterized in that, It includes a processor and a memory for storing processor-executable instructions, wherein the processor, when executing the instructions, implements the steps of the method according to any one of claims 1 to 8.

13. A computer-readable storage medium, characterized in that, It stores computer instructions that, when executed by a processor, implement the steps of the method according to any one of claims 1 to 8.

14. A computer program product, characterized in that, It includes a computer program that, when executed by a processor, implements the steps of the method according to any one of claims 1 to 8.

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