CN115984910A

CN115984910A - Fingerprint detection data sampler, fingerprint detection data sampling method and device

Info

Publication number: CN115984910A
Application number: CN202111197773.XA
Authority: CN
Inventors: 潘圣莹
Original assignee: Silead Inc
Current assignee: Silead Inc
Priority date: 2021-10-14
Filing date: 2021-10-14
Publication date: 2023-04-18

Abstract

The embodiment of the specification provides a fingerprint detection data sampler, a fingerprint detection data sampling method and a fingerprint detection data sampling device, wherein the method comprises the following steps: every fingerprint detection data sampler and an ultrasonic wave pixel unit electric connection in the ultrasonic wave pixel array, fingerprint detection data sampler includes: the first capacitor is electrically connected with the first switch; a reset signal is stored in the first capacitor by turning on the first switch; the second capacitor is electrically connected with the second switch; the fingerprint electric signal is stored in the second capacitor by turning on the second switch; the processing unit is used for determining the difference value of the fingerprint electric signal and the reset signal; and the difference value of the fingerprint electric signal and the reset signal is fingerprint detection data corresponding to the ultrasonic pixel unit. In the embodiment of the specification, the same pixel unit is sampled twice by the fingerprint detection data sampler, so that errors related to a process are effectively eliminated, and the accuracy of a result of processing fingerprint data can be effectively improved.

Description

Fingerprint detection data sampler, fingerprint detection data sampling method and device

Technical Field

The embodiment of the specification relates to the technical field of biological information detection, in particular to a fingerprint detection data sampler, a fingerprint detection data sampling method and a fingerprint detection data sampling device.

Background

Along with the rapid rise of the demand of the fingerprint sensor under the screen, the application range of the fingerprint sensor under the screen is more and more extensive, the application scenes are more and more, and the technology of the fingerprint sensor under the screen is continuously updated. The ultrasonic sensor is a sensor for converting an ultrasonic signal into other energy signals (usually, electric signals), and has the characteristics of high frequency, short wavelength, small diffraction phenomenon, good directivity, capability of being directionally propagated as a ray, and the like.

Unlike traditional optical or capacitive fingerprint identification schemes, ultrasonic sensors used for underscreen fingerprint identification are more popular due to their more flexible environmental applications. Different from the optical fingerprint identification sensor which cannot be too thin due to the limitation of the light path, the ultrasonic sensor has no limitation, so that the under-screen fingerprint identification sensor can be more easily thinned along with the thinning of electronic products.

The ultrasonic fingerprint detection sensor generally comprises a pixel array, wherein the pixel array comprises a plurality of pixel units, and when fingerprint electric signals need to be detected, the fingerprint electric signals of the pixel units in the pixel array can be read according to time sequence. Since the circuit of the pixel array inevitably has an influence on noise generated from the fingerprint data, noise reduction is indispensable when reading the fingerprint electric signal.

At present, the domestic screen ultrasonic fingerprint identification module is still in a development stage, and a technical scheme for reading fingerprint electric signals corresponding to the screen ultrasonic fingerprint detection sensor does not appear.

Disclosure of Invention

The embodiment of the specification provides a fingerprint detection data sampler, a fingerprint detection data sampling method and a fingerprint detection data sampling device, and aims to solve the problem that a fingerprint electric signal corresponding to an under-screen ultrasonic fingerprint detection sensor cannot be accurately read in the prior art.

The embodiment of this description provides a fingerprint detection data sample thief, every fingerprint detection data sample thief and an ultrasonic wave pixel element electric connection in the ultrasonic wave pixel array, ultrasonic wave pixel element includes: ultrasonic sensor, with ultrasonic sensor electric connection's ultrasonic fingerprint detection circuit, ultrasonic fingerprint detection circuit is based on the chronogenesis control signal output fingerprint signal of telecommunication of receiving, fingerprint detection data sample thief includes: the first capacitor is electrically connected with the first switch; a reset signal is stored in the first capacitor by turning on the first switch; the reset signal is a potential signal output by resetting the ultrasonic fingerprint detection circuit; the second capacitor is electrically connected with the second switch; a fingerprint electric signal is stored in the second capacitor by turning on the second switch; the first switch and the second switch are electrically connected with the output end of the ultrasonic fingerprint detection circuit; the processing unit is used for reading the reset signal in the first capacitor and the fingerprint electric signal in the second capacitor and determining the difference value between the fingerprint electric signal and the reset signal; wherein, the difference value of the fingerprint electric signal and the reset signal is fingerprint detection data corresponding to the ultrasonic wave pixel unit.

An embodiment of the present specification provides a fingerprint detection data sampling method, including: resetting an ultrasonic fingerprint detection circuit of each ultrasonic pixel unit in the ultrasonic pixel array, wherein the ultrasonic fingerprint detection circuit outputs a reset signal; switching on a first switch in the fingerprint detection data sampler corresponding to each ultrasonic pixel unit, and storing the reset signal into a first capacitor; providing an excitation signal, applying the excitation signal to the ultrasonic pixel array to enable the ultrasonic pixel array to generate an ultrasonic signal; an ultrasonic sensor in each ultrasonic pixel unit of the ultrasonic pixel array provides a detected fingerprint electric signal to the ultrasonic fingerprint detection circuit for detection; providing a time sequence control signal to control the ultrasonic fingerprint detection circuit to perform fingerprint detection and output a fingerprint electric signal; switching on a second switch in the fingerprint detection data sampler corresponding to each ultrasonic pixel unit, and storing the fingerprint electric signal into a second capacitor; acquiring fingerprint detection data corresponding to each ultrasonic pixel unit; the fingerprint detection data is a difference value between a fingerprint electric signal and a reset signal output by a fingerprint detection data sampler connected with the ultrasonic pixel unit.

An embodiment of the present specification further provides a fingerprint detection data sampling apparatus, including: the ultrasonic fingerprint detection circuit comprises a reset module, a detection module and a control module, wherein the reset module is used for resetting the ultrasonic fingerprint detection circuit of each ultrasonic pixel unit in the ultrasonic pixel array, and the ultrasonic fingerprint detection circuit outputs a reset signal; the first storage module is used for conducting a first switch in the fingerprint detection data sampler corresponding to each ultrasonic pixel unit and storing the reset signal into a first capacitor; the processing module is used for providing an excitation signal, and applying the excitation signal to the ultrasonic pixel array so as to enable the ultrasonic pixel array to generate an ultrasonic signal; the detection module is used for providing a detected fingerprint electric signal to the ultrasonic fingerprint detection circuit for detection by the ultrasonic sensor in each ultrasonic pixel unit of the ultrasonic pixel array; the output module is used for providing a time sequence control signal to control the ultrasonic fingerprint detection circuit to carry out fingerprint detection and output a fingerprint electric signal; the second storage module is used for conducting a second switch in the fingerprint detection data sampler corresponding to each ultrasonic pixel unit and storing the fingerprint electric signal into a second capacitor; the acquisition module is used for acquiring fingerprint detection data corresponding to each ultrasonic pixel unit; the fingerprint detection data is a difference value between a fingerprint electric signal and a reset signal output by a fingerprint detection data sampler connected with the ultrasonic pixel unit.

An embodiment of the present specification provides a fingerprint detection data sampling method, including: providing an excitation signal, applying the excitation signal to an ultrasonic pixel array to enable the ultrasonic pixel array to generate an ultrasonic signal; an ultrasonic sensor in each ultrasonic pixel unit of the ultrasonic pixel array provides a detected fingerprint electric signal to the ultrasonic fingerprint detection circuit for detection; providing a time sequence control signal to control the ultrasonic fingerprint detection circuit to perform fingerprint detection and output a fingerprint electric signal; switching on a second switch in the fingerprint detection data sampler corresponding to each ultrasonic pixel unit, and storing the fingerprint electric signal into a second capacitor; resetting the ultrasonic fingerprint detection circuit of each ultrasonic pixel unit in the ultrasonic pixel array, wherein the ultrasonic fingerprint detection circuit outputs a reset signal; switching on a first switch in the fingerprint detection data sampler corresponding to each ultrasonic pixel unit, and storing the reset signal into a first capacitor; acquiring a reset signal in a first capacitor and a fingerprint electric signal in a second capacitor corresponding to each ultrasonic pixel unit; and taking the difference value of the fingerprint electric signal in the second capacitor corresponding to each ultrasonic pixel unit and the reset signal in the first capacitor as fingerprint detection data corresponding to each ultrasonic pixel unit.

An embodiment of the present specification further provides a fingerprint detection data sampling apparatus, including: the first processing module is used for providing an excitation signal, and applying the excitation signal to the ultrasonic pixel array so as to enable the ultrasonic pixel array to generate an ultrasonic signal; the detection module is used for providing a detected fingerprint electric signal to the ultrasonic fingerprint detection circuit for detection by the ultrasonic sensor in each ultrasonic pixel unit of the ultrasonic pixel array; the output module is used for providing a time sequence control signal to control the ultrasonic fingerprint detection circuit to carry out fingerprint detection and output a fingerprint electric signal; the first storage module is used for conducting a second switch in the fingerprint detection data sampler corresponding to each ultrasonic pixel unit and storing the fingerprint electric signal into a second capacitor; the ultrasonic fingerprint detection circuit is used for detecting the ultrasonic fingerprint of each ultrasonic pixel unit in the ultrasonic pixel array; the second storage module is used for conducting the first switches in the fingerprint detection data samplers corresponding to the ultrasonic pixel units and storing the reset signals into the first capacitors; the acquisition module is used for acquiring a reset signal in a first capacitor and a fingerprint electric signal in a second capacitor corresponding to each ultrasonic pixel unit; and the second processing module is used for taking the difference value between the fingerprint electric signal in the second capacitor corresponding to each ultrasonic pixel unit and the reset signal in the first capacitor as fingerprint detection data corresponding to each ultrasonic pixel unit.

This specification embodiment provides a fingerprint detection data sample thief, can be in a fingerprint detection data sample thief of ultrasonic wave fingerprint detection circuit's of every ultrasonic wave pixel cell output electric connection in ultrasonic wave pixel array, fingerprint detection data sample thief can include: a first capacitor electrically connected with a first switch is used for carrying out reset operation on the ultrasonic fingerprint detection circuit and outputting a potential signal, and the potential signal can be stored in the first capacitor by turning on the first switch; the fingerprint electric signal can be stored in the second capacitor by turning on the second switch; the processing unit may be configured to read the reset signal in the first capacitor and the fingerprint electrical signal in the second capacitor, and determine a difference between the fingerprint electrical signal and the reset signal. Therefore, the same pixel unit can be sampled twice through the fingerprint detection data sampler, the fingerprint electric signal and the reset signal are read twice through the discontinuous opening of the first switch S1 and the second switch S2 in time sequence, and the difference value of the fingerprint electric signal and the reset signal read twice is used as the fingerprint detection data of the ultrasonic pixel unit to be output. Therefore, errors related to the process can be effectively eliminated, the accuracy of the result of processing the fingerprint data by the subsequent integrated circuit can be effectively improved, and a good data base is laid for amplifying the difference value of the fingerprint peak and the fingerprint valley.

Drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the disclosure, are incorporated in and constitute a part of this specification, and are not intended to limit the embodiments of the disclosure. In the drawings:

fig. 1 is a schematic top view of an ultrasonic fingerprint detection sensor provided in an embodiment of the present disclosure;

fig. 2 is a schematic cross-sectional structure diagram of an ultrasonic fingerprint detection sensor provided in an embodiment of the present disclosure;

fig. 3 is a schematic structural diagram of an ultrasonic pixel unit included in an ultrasonic fingerprint detection sensor according to an embodiment of the present disclosure;

FIG. 4 is a schematic diagram of a fingerprint detection data sampler provided in accordance with an embodiment of the present description;

FIG. 5 is a schematic diagram illustrating steps of a fingerprint detection data sampling method according to an embodiment of the present disclosure;

fig. 6A is a circuit topology diagram of an ultrasonic fingerprint detection circuit including three MOS transistors according to an embodiment of the present disclosure;

fig. 6B is a circuit topology diagram of an ultrasonic fingerprint detection circuit including four MOS transistors according to an embodiment of the present disclosure;

fig. 6C is a circuit topology diagram of an ultrasonic fingerprint detection circuit including four MOS transistors according to an embodiment of the present specification;

fig. 6D is a circuit topology diagram of an ultrasonic fingerprint detection circuit including four MOS transistors according to an embodiment of the present specification;

fig. 6E is a circuit topology diagram of an ultrasonic fingerprint detection circuit including four MOS transistors according to an embodiment of the present disclosure;

fig. 7 is a schematic structural diagram of a fingerprint detection data sampling apparatus provided in an embodiment of the present specification;

FIG. 8 is a schematic diagram illustrating steps of a fingerprint detection data sampling method provided in accordance with an embodiment of the present disclosure;

FIG. 9 is a timing diagram illustrating control of an ultrasonic fingerprint detection circuit provided in accordance with an embodiment of the present disclosure;

fig. 10 is a schematic structural diagram of a fingerprint detection data sampling apparatus provided in an embodiment of the present disclosure.

Detailed Description

The principles and spirit of the embodiments of the present specification will be described with reference to a number of exemplary embodiments. It should be understood that these embodiments are presented merely to enable those skilled in the art to better understand and to implement the embodiments of the present description, and are not intended to limit the scope of the embodiments of the present description in any way. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

As will be appreciated by one skilled in the art, implementations of the embodiments of the present description may be embodied as a system, an apparatus, a method, or a computer program product. Therefore, the disclosure of the embodiments of the present specification can be embodied in the following forms: entirely hardware, entirely software (including firmware, resident software, micro-code, etc.), or a combination of hardware and software.

Although the flow described below includes operations that occur in a particular order, it should be appreciated that the processes may include more or less operations that are performed sequentially or in parallel (e.g., using parallel processors or a multi-threaded environment).

It will be understood that when an element is referred to as being "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a single embodiment.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The embodiment of the specification provides a fingerprint detection data sampler and a method for sampling fingerprint detection data by using the fingerprint detection data sampler. The fingerprint detection data sampler can be applied to electronic equipment such as but not limited to mobile smart phones, tablet electronic equipment, computers, GPS navigators, personal digital assistants and intelligent wearable equipment, is used for collecting fingerprint detection data to perform fingerprint identification, and can realize fingerprint unlocking, user identity verification, authority acquisition and the like.

In a feasible implementation scenario, the fingerprint detection data sampling method provided in the embodiments of the present specification may preferably be applied to products related to an ultrasonic fingerprint detection sensor, where the ultrasonic fingerprint detection sensor is configured in a smart phone, and the smart phone may collect fingerprint detection data of a user based on a fingerprint detection data sampler, so as to match the fingerprint detection data with fingerprint information stored in correspondence with the user, so as to implement identity verification on the current user, and thus determine whether the current user has a corresponding authority to perform related operations such as screen unlocking, user identity verification, and authority acquisition on the smart phone.

A schematic top-view structure diagram of an ultrasonic fingerprint detection sensor may be as shown in fig. 1, where the ultrasonic fingerprint detection sensor may include a glass substrate 1 and an ultrasonic pixel array 2 disposed on the glass substrate 1, and the ultrasonic pixel array 2 includes a plurality of ultrasonic pixel units 201. The plurality of ultrasonic wave pixel units 201 can be arranged on the glass substrate 1 in a regular form of multiple rows and multiple columns, so that the surface setting space of the glass substrate 1 is fully utilized, and the setting density of the ultrasonic wave pixel units 201 is improved. The glass substrate 1 may be a substrate on which a TFT (Thin Film Transistor) process is performed, and a conductive Film is formed thereon, and the ultrasonic pixel unit 201 is formed on the glass substrate 1 by processing and manufacturing the conductive Film.

In this scenario, the glass substrate 1 may further have a pin 3 for connecting to another IC (integrated circuit) chip and an ASIC (application specific integrated circuit) control chip, so as to implement connection between the ultrasonic fingerprint detection sensor and the other IC chip, and supply of power (constant voltage dc power Vcc, reset voltage) and signal control. The voltage value of the constant voltage dc power Vcc may be set and selected according to actual conditions, for example, may be selected from 6V to 12V. The Reset voltage may be Reset or Reset, and the value of the Reset voltage may be set and selected according to actual conditions, for example, may be 0V, which is not limited in this embodiment of the present disclosure.

In the present scenario example, the structure of the ultrasonic fingerprint detection sensor provided with the row selection module is only given as an example in fig. 1. It is understood that in some embodiments, only the column selection module may be further provided, or both the row selection module and the column selection module may be provided, which may be specifically set according to actual situations, and this is not limited in this specification.

The schematic cross-sectional structure of the ultrasonic fingerprint detection Sensor can be as shown in fig. 2, wherein each ultrasonic pixel unit 201 can include an ultrasonic Sensor (Sensor) and an ultrasonic fingerprint detection circuit 201a electrically connected to the ultrasonic Sensor. Specifically, the ultrasonic sensor includes a bottom Electrode 201b (Electrode), and the ultrasonic fingerprint detection circuit 201a is connected to the ultrasonic sensor through the bottom Electrode 201 b.

As shown in fig. 1 and 2, the ultrasonic sensor may include a piezoelectric material 4, an electrode 5, a protective film 6, and a cover 7, which are stacked in this order from bottom to top. The cover layer 7 may be a cover glass, for being pressed or touched by a finger of a user. The protective film 6 isolates the electrodes 5 from the cover layer 7, can buffer the pressing or touch operation of fingers of a user, and protects the electrodes 5 and the structures such as the piezoelectric material 4 and the ultrasonic pixel array 2 on the lower layer.

In actual operation, the electrode 5 is connected to an alternating voltage, and after receiving an alternating Excitation voltage Signal (Excitation Signal), the piezoelectric material 4 is triggered to vibrate to generate an ultrasonic Signal with ultrasonic frequency, and the ultrasonic Signal is emitted (TX) to a user's finger pressing on the cover 7, so as to establish a stable or standard ultrasonic field. When the user's finger presses the cover plate 7, the standard wave field originally established by the ultrasonic signal is changed due to the intervention of the user's finger, specifically including at least one change in amplitude, frequency or phase of the ultrasonic signal. As shown in fig. 2, an air gap is formed between the fingerprint valley of the finger and the outer surface of the sensor, and the fingerprint ridge is attached to the outer surface of the sensor. Then, the amplitude, frequency, or phase of the ultrasonic signal incident on the fingerprint valley is less varied, and the amplitude, frequency, or phase of the ultrasonic signal incident on the fingerprint ridge is less varied. The piezoelectric material 4 can receive and sense (RX) the above-mentioned change of the ultrasonic wave field due to the intervention or disturbance of the user's finger and convert the changed acoustic wave signal into a fingerprint electric signal. The piezoelectric material 4 further supplies the converted fingerprint electric signal to the ultrasonic fingerprint detection circuit 201a electrically connected thereto through the bottom electrode 201 b.

In one embodiment, the ultrasonic sensor may be time-shared as a transmitting unit of the ultrasonic wave and a receiving unit of the ultrasonic wave. The ultrasonic sensor of the embodiment of the present specification transmits only ultrasonic waves or receives only ultrasonic waves during the same period of time. Alternatively, when the ultrasonic sensor is transmitting ultrasonic waves, the ultrasonic waves are not received. Accordingly, when the ultrasonic wave is received, the ultrasonic wave is not transmitted.

In the present embodiment, when the electrodes 5 receive the excitation voltage signal, the whole area array of the piezoelectric material 4 is triggered to vibrate to generate the ultrasonic signal. When detecting the fingerprint electric signal, the piezoelectric material 4 receives the change of the ultrasonic wave field and outputs the fingerprint electric signal to the ultrasonic pixel array 2 covered under the piezoelectric material according to a preset rule. Since the ultrasonic pixel array 2 includes a plurality of ultrasonic pixel cells 201 arranged in an array form, the predetermined rule may include: the fingerprint electric signals are output according to rows or the fingerprint electric signals are output according to columns. Of course, the predetermined rule is not limited to the above examples, and other modifications are possible for those skilled in the art in light of the technical spirit of the embodiments of the present disclosure, and the functions and effects achieved by the modifications are also encompassed in the scope of the embodiments of the present disclosure.

In this embodiment, outputting the fingerprint electric signal by a line may further include: only one row of fingerprint electric signals are output each time, and the fingerprint electric signals of all the rows are sequentially output according to time sequence. Or outputting the fingerprint electric signals of n rows each time, and sequentially outputting the fingerprint electric signals of all the rows according to time sequence. In this way, as shown in fig. 2, the ultrasonic pixel array 2 may receive a Row selection signal Row and control the manner in which the piezoelectric material 4 outputs the fingerprint electrical signal to the ultrasonic pixel array 2 based on the Row selection signal Row.

Similarly, the column-wise output of the fingerprint electrical signal can be explained as follows, and is not described herein.

In this embodiment, a schematic structural diagram of one ultrasonic pixel unit 201 included in the ultrasonic fingerprint detection sensor may be as shown in fig. 3, each ultrasonic fingerprint detection circuit includes at least three MOS transistors (M1, M2, M3 …), and fig. 3 is a schematic diagram of an ultrasonic fingerprint detection circuit including only three MOS transistors. In fig. 3, the Electrode is a bottom Electrode 201b, the gate of the first MOS transistor M1 is connected to the ultrasonic sensor and the drain of the third MOS transistor M3, the source is connected to the drain of the second MOS transistor M2, and the drain is connected to a constant voltage dc power supply Vcc. The source of the second MOS transistor M2 is used to output a signal Dn, which is a fingerprint electrical signal stored in the gate of the first MOS transistor M1. Fig. 3 further includes a Row selection signal Row connected to the gate of the second MOS transistor M2, a first driving signal OD _1 connected to the gate and the input of the third MOS transistor M3, and a Bias signal Bias. The timing control signal Row connected to the gate of the second MOS transistor M2 can control the on/off of the second MOS transistor M2 to control whether the fingerprint electrical signal stored in the gate of the first MOS transistor M1 is output. Specifically, when the voltage of the Row selection signal Row is at a high level, the second MOS transistor M2 is turned on. When the voltage of the Row selection signal Row is at a low level, the second MOS transistor M2 is turned off.

In this embodiment, the voltage value of the constant voltage dc power Vcc in fig. 3 can be set and selected according to actual situations, for example, can be selected from 6V to 12V, and the function is to make the first MOS transistor M1 always operate in the saturation region, so that the first MOS transistor M1 forms a Source Follower (Source Follower). In this way, the signal stored in the gate of the first MOS transistor M1 can be output from the source of the second MOS transistor M2 when the second MOS transistor M2 is turned on or turned on.

In this embodiment, the plurality of ultrasonic pixel units 201 are independent of each other, there is no signal connection or signal sharing relationship between the plurality of ultrasonic pixel units 201, and the ultrasonic fingerprint detection circuit 201a only receives the electrical signal transmitted from the corresponding ultrasonic sensor. Each ultrasonic pixel cell 201 acts as a separate or independent working unit, and the respective ultrasonic pixel cells 201 do not interfere with each other during operation.

It should be noted that the layout shape (layout) of the ultrasonic pixel unit 201 in the embodiment of the present specification is not limited to the rectangle or the square illustrated in fig. 3, and may include any other feasible shape, which is not limited in the embodiment of the present specification.

Referring to fig. 4, the present embodiment may provide a fingerprint detection data sampler. Every fingerprint detection data sample thief and an ultrasonic wave pixel cell electric connection in the ultrasonic wave pixel array, ultrasonic wave pixel cell includes: ultrasonic sensor, with ultrasonic sensor electric connection's ultrasonic fingerprint detection circuit, ultrasonic fingerprint detection circuit is based on the chronogenesis control signal output fingerprint signal of telecommunication of receipt, and fingerprint detection data sample thief can include: a first switch S1, a first capacitor C2, a second switch S2, a second capacitor C3 and a processing unit 401.

First electric capacity C2 can with first switch S1 electric connection, reset signal can be for carrying out the potential signal that the operation was exported that resets to ultrasonic fingerprint detection circuit, can be through switching on first switch with reset signal storage in first electric capacity C2.

In this embodiment, the first end of the first switch S1 may be electrically connected to the output end of the ultrasonic fingerprint detection circuit, the second end of the first switch S1 may be electrically connected to the first end of the first capacitor C2, and the second end of the first capacitor C2 may be grounded.

In this embodiment, the Reset signal may be a Vdb Reset voltage value that gives the same potential to the ultrasonic fingerprint detection circuits of all the ultrasonic pixel units in the pixel array, and the Reset voltage value output by the ultrasonic fingerprint detection circuits.

Second electric capacity C3 can with second switch S2 electric connection, the fingerprint signal of telecommunication of ultrasonic wave fingerprint detection circuit output can be through switching on second switch S2 storage in second electric capacity C3. The first switch S1 and the second switch S2 are electrically connected with the output end of the ultrasonic fingerprint detection circuit.

In this embodiment, the first terminal of the second switch S2 may be electrically connected to the output terminal of the ultrasonic fingerprint detection circuit, the second terminal of the second switch S2 may be electrically connected to the first terminal of the second capacitor C3, and the second terminal of the second capacitor C3 may be grounded.

The processing unit 401 may be configured to read the reset signal in the first capacitor C2 and the fingerprint electrical signal in the second capacitor C3 and determine a difference between the fingerprint electrical signal and the reset signal. Wherein, the difference value of the fingerprint electric signal and the reset signal is fingerprint detection data corresponding to the ultrasonic wave pixel unit.

In this embodiment, two ends of the processing unit 401 may be electrically connected to the second end of the first capacitor C2 and the second end of the second capacitor C3, respectively.

In this embodiment, the Current Mirror in fig. 4 may be a Current Mirror, and the Current Mirror may also be an output end of the ultrasonic fingerprint detection circuit.

In this embodiment, since the row selection circuit and the column selection circuit in the pixel array are all completed on the TFT backplane, the noise effect on the fingerprint data due to the TFT process needs to be considered. When the input signal of the pixel array is normal TX, RX, the TFT transistor Gate of SF in the pixel array (e.g., the Gate of M1 in fig. 3) stores the detected fingerprint electrical signal, and the row switch is turned on to transmit the fingerprint electrical signal to the corresponding Integrated Circuit (IC) channel. Because the adopted LTPS (low-temperature polysilicon technology) process is used for manufacturing the TFT backboard, the LTPS has the advantage of higher mobility, but the relative defects are grain boundaries and surface states, the existence of the grain boundaries can enable the TFT to have larger leakage current, and meanwhile, the grain boundaries are not uniformly distributed in the LTPS, so that the uniformity of the whole pixel array is poorer, and further the on-state performance of the TFT tubes of SF (sulfur hexafluoride) at different positions in the pixel array is possibly inconsistent, namely, the data values detected by the pixel points of the same fingerprint electric signal at different positions are different. The above-mentioned difference is related to non-uniformity caused by the pixel array process, and is not changed after the manufacturing process is completed, and the above-mentioned difference can be referred to as the noise floor of the pixel array.

In the present embodiment, sampling may be performed twice based on the above-mentioned problem, and a read Reset signal (Reset data) may be added once to the read fingerprint electric signal output from the ultrasonic fingerprint detection circuit, so that the nonuniformity due to the process may be quantified and recorded to some extent. Specifically, the Reset signal of each ultrasonic pixel unit can be read after a Vdb Reset voltage value with the same potential is given to all ultrasonic pixel units in the ultrasonic pixel array, and the Reset signal of each ultrasonic pixel unit can be used as the noise floor of the pixel array.

In this embodiment, the read fingerprint electrical signal output by the ultrasonic fingerprint detection circuit itself contains noise, and the ultrasonic pixel unit at the same position has two data, namely the fingerprint electrical signal and the reset signal, so that the processing unit 401 can use the difference value between the fingerprint electrical signal and the reset signal as the fingerprint detection data corresponding to the ultrasonic pixel unit, thereby eliminating the position-related deviation and alleviating the deviation caused by process non-uniformity.

In this embodiment, the same ultrasonic pixel unit may be sampled twice, and the first switch S1 and the second switch S2 are discontinuously turned on twice in time sequence, so as to read the fingerprint electrical signal and the reset signal, and output a difference value between the fingerprint electrical signal and the reset signal, which are read twice, as fingerprint detection data of the ultrasonic pixel unit.

In this embodiment, the specific derivation process is as follows:

the relationship between the actual electrical fingerprint signal and the actual read electrical fingerprint signal can be shown as the following formula:

V _ij ′＝V _ij -V _Leak +n _ij

wherein, V _ij I =1,2,3 … j =1,2,3 … for the real fingerprint electric signals corresponding to the ultrasonic wave pixel units in the ith row and the jth column in the pixel array; v _ij ' is a fingerprint electric signal actually read by the ultrasonic pixel unit in the ith row and the jth column in the pixel array; v _Leak For potential drop due to leakage, V _Leak K is a leakage coefficient, T is a waiting time before reading, T is related to a position of a pixel point, T of a pixel unit of an ultrasonic pixel unit in a first row and a first column is minimum, and the waiting time T is larger the farther the position is; n is a radical of an alkyl radical _ij A deviation due to the non-uniformity of the TFT tubes of the SF in each ultrasonic fingerprint detection circuit.

The relationship between the real reset signal and the actually read reset signal can be shown as the following formula:

R _ij ′＝R _ij -V _LeakR +n _ij ′

wherein R is _ij Real reset signals corresponding to ultrasonic pixel units in the ith row and the jth column in the pixel array; r _ij ' i =1,2,3 … j =1,2,3 …, which is a reset signal actually read by an ultrasonic pixel unit in the ith row and the jth column in the pixel array; v _LeakR Potential drop due to leakage corresponding to reset operation; n is a radical of an alkyl radical _ij ' deviation due to nonuniformity of TFT tubes of SF in each ultrasonic fingerprint detection circuit. Since the fingerprint electric signal and the reset signal are respectively read from the same ultrasonic pixel unit, namely n is _ij And n _ij ' is the deviation due to the non-uniformity of the TFT tubes of SF in the same ultrasonic pixel cell, so the process error is almost the same, i.e. n _ij ≈n _ij '. This gives:

V _ij '-R _ij '＝V _ij -V _Leak +n _ij -(R _ij -V _LeakR +n _ij ')

＝(V _ij -R _ij )+(V _LeakR -V _Leak )+(n _ij -n _ij ')

wherein, due to V _LeakR ＝K _R ×T，V _Leak = K × T, therefore, the above equation can be simplified as:

V _ij '-R _ij '＝(V _ij -R _ij )+(K _R -K)×T+(n _ij -n _ij ')

if the leakage coefficient of the reset signal is the same as that of the fingerprint electrical signal, K _R Infinitely close to K, i.e. K _R K, the above equation can be simplified to:

V _ij ′-R _ij ′≈V _ij -R _ij

therefore, the difference between the actually read fingerprint electric signal and the reset signal is infinitely close to the difference between the real fingerprint electric signal and the real reset signal, and based on the difference, the difference value between the fingerprint electric signal and the reset signal can be output as the fingerprint detection data of the ultrasonic pixel unit. Therefore, the method can effectively eliminate the process-related errors to the maximum extent, further effectively improve the accuracy of the result of processing the fingerprint data by an Integrated Circuit (IC), and lay a good foundation for amplifying the difference value of the fingerprint peak and the fingerprint valley.

In one embodiment, as shown in fig. 4, the first switch S1 may be connected in parallel with the second switch S2, the first switch S1 and the second switch S2 not being turned on simultaneously. Therefore, the fingerprint electric signal and the reset signal can be read by discontinuously opening the first switch S1 and the second switch S2 twice in time sequence.

In one embodiment, the processing unit 401 may include a switched capacitor differential amplifier, so that the difference between the fingerprint electrical signal and the reset signal may be obtained by using the switched capacitor differential amplifier, and the difference between the fingerprint electrical signal and the reset signal may be amplified. The difference value of the fingerprint electric signal and the reset signal is only output finally by adopting the mode, two intermediate values of the fingerprint electric signal and the reset signal cannot be acquired, but the difference value of the fingerprint electric signal and the reset signal can be determined more conveniently by adopting the mode.

In this embodiment, the switched capacitor differential amplifier may include two input terminals, and the two input terminals may be electrically connected to the first capacitor C2 and the second capacitor C3, respectively, for inputting the fingerprint electrical signal and the reset signal.

In one embodiment, the processing unit 401 may include a processor, and the processing unit 401 may sequentially acquire the fingerprint electrical signal and the reset signal and determine a difference value between the fingerprint electrical signal and the reset signal by using the processor. It is understood that, in some embodiments, the processing unit 401 may be configured to output only the acquired fingerprint electrical signal and the reset signal, and perform a difference operation on the fingerprint electrical signal and the reset signal of each ultrasonic pixel unit before performing fingerprint identification. The specific situation can be determined according to actual situations, and the embodiment of the present specification does not limit the specific situation.

In the embodiment, the fingerprint electrical signal and the reset signal are directly output, and the heterogeneity caused by the process can be quantized and recorded, so that the noise of the pixel array can be analyzed subsequently, and data support is provided for the subsequent analysis work.

From the above description, it can be seen that the embodiments of the present specification achieve the following technical effects: can be in ultrasonic pixel array every ultrasonic wave pixel unit's an ultrasonic fingerprint detection circuit's output electric connection fingerprint detection data sampler, fingerprint detection data sampler can include: the potential signal output by the ultrasonic fingerprint detection circuit through the reset operation of the first capacitor electrically connected with the first switch can be stored in the first capacitor by turning on the first switch; the fingerprint electric signal can be stored in the second capacitor by turning on the second switch; the processing unit may be configured to read the reset signal in the first capacitor and the fingerprint electrical signal in the second capacitor and determine a difference between the fingerprint electrical signal and the reset signal. Therefore, the same ultrasonic pixel unit can be sampled twice through the fingerprint detection data sampler, the fingerprint electric signal and the reset signal are read twice through the discontinuous opening of the first switch S1 and the second switch S2 in time sequence, and the difference value of the fingerprint electric signal and the reset signal which are read twice is used as the fingerprint detection data of the ultrasonic pixel unit to be output. Therefore, errors related to the process can be effectively eliminated, the accuracy of the result of processing the fingerprint data by the subsequent integrated circuit can be effectively improved, and a good data base is laid for amplifying the difference value of the fingerprint peak and the fingerprint valley.

Referring to fig. 5, the present embodiment can provide a method for sampling fingerprint detection data by using the above fingerprint detection data samples. The fingerprint detection data sampling method may include the following steps.

S501: and resetting the ultrasonic fingerprint detection circuit of each ultrasonic pixel unit in the ultrasonic pixel array, wherein the ultrasonic fingerprint detection circuit outputs a reset signal.

S502: and switching on a first switch in the fingerprint detection data sampler corresponding to each ultrasonic pixel unit, and storing the reset signal into a first capacitor.

S503: and providing an excitation signal, applying the excitation signal to the ultrasonic pixel array, and enabling the ultrasonic pixel array to generate an ultrasonic signal.

S504: the ultrasonic sensor in each ultrasonic pixel unit of the ultrasonic pixel array provides the detected fingerprint electric signal to the ultrasonic fingerprint detection circuit for detection.

S505: and providing a time sequence control signal to control the ultrasonic fingerprint detection circuit to perform fingerprint detection and output a fingerprint electric signal.

S506: and switching on a second switch in the fingerprint detection data sampler corresponding to each ultrasonic pixel unit, and storing the fingerprint electric signal into a second capacitor.

S507: acquiring fingerprint detection data corresponding to each ultrasonic pixel unit; the fingerprint detection data is a difference value between a fingerprint electric signal and a reset signal output by a fingerprint detection data sampler connected with the ultrasonic pixel unit.

In this embodiment, a Vdb Reset voltage value with the same potential may be first applied to all the ultrasonic pixel units in the ultrasonic pixel array to perform a Reset operation on the ultrasonic fingerprint detection circuit 201a of each ultrasonic pixel unit in the ultrasonic pixel array, and the ultrasonic fingerprint detection circuit 201a outputs a Reset signal. An excitation signal is provided and applied to the reset ultrasonic pixel array 2 for fingerprint detection, so that a correlation exists between the read reset signal and the fingerprint electric signal.

In this embodiment, the ultrasonic pixel array 2 may include an ultrasonic sensor, the ultrasonic sensor includes a piezoelectric material 4 and an electrode 5, and an Excitation Signal (Excitation Signal) is applied to the electrode 5 to trigger the piezoelectric material 4 to vibrate and generate an ultrasonic Signal.

In the present embodiment, the ultrasonic signal generated by the ultrasonic pixel array 2 establishes a stable or standard ultrasonic field, when the user presses the cover 7 with a finger, the standard ultrasonic field originally established by the ultrasonic signal is changed due to the finger, the piezoelectric material 4 can receive and sense (RX) the change of the ultrasonic field caused by the finger intervention or interference of the user, convert the changed acoustic signal into an electrical fingerprint signal, and then provide the converted electrical fingerprint signal to the ultrasonic fingerprint detection circuit 201a electrically connected to the bottom electrode 201 b.

In this embodiment, a timing control signal may be provided to control the ultrasonic fingerprint detection circuit 201a to perform fingerprint detection. Since each ultrasonic pixel unit 201 includes at least three MOS transistors as shown in fig. 3, the timing control signals may be at least three, so that the operating states of the at least three MOS transistors may be controlled, so that the second MOS transistor M2 outputs the potential signal stored in the gate of the first MOS transistor. At this time, the second switch in the fingerprint detection data sampler corresponding to each ultrasonic pixel unit 201 may be turned on, and the fingerprint electrical signal output by the ultrasonic fingerprint detection circuit 201a may be stored in the second capacitor.

In one embodiment, before acquiring fingerprint detection data corresponding to each ultrasound pixel unit, the method may further include: the switch capacitor differential amplifier is used for controlling the reset signal in the first capacitor and the fingerprint electric signal in the second capacitor to be respectively input, and comprises two input ends, so that the difference value between the fingerprint electric signal and the reset signal is obtained.

In this embodiment, after the fingerprint detection data sampler collects the reset signal and the fingerprint electrical signal, the reset signal in the first capacitor and the fingerprint electrical signal in the second capacitor may be controlled to be respectively input to the switched capacitor differential amplifier, which includes two input terminals, and the output terminal of the switched capacitor differential amplifier correspondingly outputs the difference between the fingerprint electrical signal and the reset signal, so as to obtain the fingerprint detection data corresponding to each ultrasonic pixel unit 201.

In this embodiment, the fingerprint electrical signal and the reset signal of the same ultrasonic pixel unit can be read sequentially, which greatly helps the IC process signal later, and DC (Differential Correction) can be optimized. In one embodiment, it is assumed that the reset signal value of one ultrasonic pixel unit is 1.5V, and the fingerprint electrical signal value of the same ultrasonic pixel unit is 1.51V, since the two data are respectively stored on the capacitors C2 and C3, the two input terminals of the differential amplifier can be connected together through the switched capacitor, so as to obtain a difference of 0.01V between the two, and for the difference, the signal can be amplified layer by layer subsequently, and there is no need to worry about the problem of signal saturation caused by too large amplification factor.

In the present embodiment, since the ultrasonic pixel cells 201 are independent of each other, the timing control signals of the ultrasonic pixel cells 201 are also different. In some embodiments, the fingerprint detection data output by the fingerprint detection data sampler may be read sequentially by rows. In some embodiments, the fingerprint detection data output by the fingerprint detection data sampler may also be sequentially read in columns, and the specific reading manner may be determined according to the actual row selection signal and the actual column selection signal, which is not limited in this specification.

From the above description, it can be seen that the embodiments of the present specification achieve the following technical effects: the ultrasonic fingerprint detection circuit of each ultrasonic pixel unit in the ultrasonic pixel array can be Reset by giving all the ultrasonic pixel units in the ultrasonic pixel array a Vdb Reset voltage value with the same potential, and the ultrasonic fingerprint detection circuit outputs a Reset signal. The reset signal may be stored in the first capacitor by turning on the first switch in the fingerprint detection data sampler corresponding to each ultrasonic pixel cell. And providing an excitation signal, applying the excitation signal to the reset ultrasonic pixel array, providing a time sequence control signal to control the ultrasonic fingerprint detection circuit to perform fingerprint detection, and storing the fingerprint electric signal into a second capacitor by turning on a second switch in the fingerprint detection data sampler corresponding to each ultrasonic pixel unit so that the read reset signal and the fingerprint electric signal have correlation. Furthermore, the difference value between the fingerprint electric signal and the reset signal can be obtained by utilizing the switched capacitor differential amplifier, and the fingerprint detection data corresponding to each ultrasonic pixel unit can be efficiently and conveniently obtained. Therefore, the same ultrasonic pixel unit can be sampled twice through the fingerprint detection data sampler, the fingerprint electric signal and the reset signal are read by discontinuously opening the first switch and the second switch twice in time sequence, and the difference value between the fingerprint electric signal and the reset signal read twice is output as the fingerprint detection data of the ultrasonic pixel unit. Therefore, errors related to the process can be effectively eliminated, the accuracy of the result of processing the fingerprint data by the subsequent integrated circuit can be effectively improved, and a good data base is laid for amplifying the difference value of the fingerprint peak and the fingerprint valley.

In one embodiment, each ultrasonic fingerprint detection circuit 201a includes at least three MOS transistors, and specifically, each ultrasonic fingerprint detection circuit 201a may include only three MOS transistors, or more than three MOS transistors. The circuit topology of the ultrasonic fingerprint detection circuit including three MOS transistors in the ultrasonic fingerprint detection sensor may be as shown in fig. 6A, and each ultrasonic fingerprint detection circuit 201a may only include three MOS transistors, which are a first MOS transistor M1, a second MOS transistor M2, and a third MOS transistor M3. In another possible embodiment, a circuit topology of the ultrasonic fingerprint detection circuit including four MOS transistors may be as shown in fig. 6B to 6E, where each ultrasonic fingerprint detection circuit 201a further includes a fourth MOS transistor M4 on the basis that the above-mentioned embodiment includes three MOS transistors, that is, each ultrasonic fingerprint detection circuit 201a includes four MOS transistors.

In this embodiment, all the MOS transistors are preferably the same type of MOS transistor, for example, both N-type MOS transistors or both P-type MOS transistors. Therefore, the number of the types of the electronic components is small, and the preparation complexity of the detection circuit is reduced. Of course, the type of the MOS transistor is not limited thereto, and in other possible embodiments, the MOS transistor may be an N-type MOS transistor, and a part of the MOS transistors may be P-type MOS transistors, which is not limited in the present invention.

Each ultrasonic fingerprint detection circuit 201a receives at least three corresponding sequential control signals respectively, and the at least three sequential control signals are independent to control the working states of at least three MOS tubes. The at least three corresponding timing control signals received by each ultrasonic fingerprint detection circuit 201a may be that the at least three timing control signals received by the same ultrasonic fingerprint detection circuit 201a are only used for operating at least three MOS transistors included in the controller, the timing control signals received by any two ultrasonic fingerprint detection circuits 201a do not have an intersection or sharing relationship, and each ultrasonic fingerprint detection circuit 201a works independently. By such a design, the situation of error accumulation caused by the crossing or sharing of the timing control signal between two or more ultrasonic fingerprint detection circuits 201a can be avoided.

As shown in fig. 6A, TX is an ultrasonic signal emitted to a Finger of a user pressing on the cover 7, sensor is an ultrasonic Sensor, and Finger is Finger. In an embodiment including only three MOS transistors, the timing control signals are also three. In one possible implementation scenario, the three timing control signals are: a Row selection signal Row connected with the grid electrode of the second MOS tube M2, a first driving signal OD _1 (Over Drive) connected with the grid electrode and the input electrode of the third MOS tube M3 and a Bias signal Bias.

In the embodiment in which all three MOS transistors are N-type MOS transistors as illustrated in fig. 6A, the drain of the second MOS transistor M2 serves as an input electrode connected to the gate of the first MOS transistor M1, and the source serves as an output electrode for outputting the fingerprint peak signal. The source of the third MOS transistor M3 is used as an input electrode for receiving the Bias signal Bias, and the drain is used as an output electrode connected to the gate of the first MOS transistor M1. The connection relationship of the three MOS tubes and the ultrasonic sensor is as follows: first MOS pipe M1 and third MOS pipe M3 are established ties, and ultrasonic sensor connects between first MOS pipe M1 and third MOS pipe M3, and a tie point is shared to the three. The method specifically comprises the following steps: the grid electrode of the first MOS tube M1 is connected with the ultrasonic sensor and the drain electrode of the third MOS tube M3, the source electrode is connected with the drain electrode of the second MOS tube M2, and the drain electrode is connected with a constant-voltage direct-current power supply Vcc. The source of the second MOS transistor M2 is used to output a signal Dn, which is a fingerprint electrical signal stored in the gate of the first MOS transistor M1.

The voltage value of the constant voltage dc power Vcc may be set and selected according to actual conditions, for example, may be selected from 6V to 12V, and the function is to make the first MOS transistor M1 always operate in a saturation region, so that the first MOS transistor M1 forms a Source Follower (Source Follower). In this way, the signal stored in the gate of the first MOS transistor M1 can be output from the source of the second MOS transistor M2 when the second MOS transistor M2 is turned on or turned on.

The timing control signal input and the structural connection relationship when the three MOS transistors are all N-type MOS transistors are described above, but the present embodiment is not limited thereto. When three MOS pipes are P type MOS pipes, three sequential control signals: the Row selection signal Row, the first driving signal OD _1 and the Bias signal Bias are respectively connected to the gate of the second MOS transistor M2, the gate of the third MOS transistor M3 and the drain. The structure connection relation is as follows: the grid electrode of the first MOS tube M1 is connected with the ultrasonic sensor and the source electrode of the third MOS tube M3, the drain electrode is connected with the source electrode of the second MOS tube M2, and the source electrode is connected with a constant-voltage direct-current power supply Vcc.

In the embodiment that all the three MOS transistors are P-type MOS transistors, the source of the second MOS transistor M2 serves as an input electrode connected to the gate of the first MOS transistor M1, and the drain serves as an output electrode for outputting the fingerprint peak signal. The drain of the third MOS transistor M3 is used as an input electrode for receiving the Bias signal Bias, and the source is used as an output electrode connected to the gate of the first MOS transistor M1.

In the embodiment illustrated in fig. 6B to 6E including four MOS transistors, the number of the timing control signals is also four, which are: the driving circuit comprises a Row selection signal Row connected with the grid electrode of a second MOS tube M2, a first driving signal OD _1 and a Bias signal Bias connected with the grid electrode of a third MOS tube M3 and an input electrode, and a second driving signal OD _2 connected with the grid electrode of a fourth MOS tube M4.

Similarly, in the embodiment in which the four MOS transistors are N-type MOS transistors as illustrated in fig. 6B to 6D, the drain of the second MOS transistor M2 is used as the input electrode connected to the gate of the first MOS transistor M1, and the source is used as the output electrode for outputting the fingerprint peak signal. The source of the third MOS transistor M3 is used as an input electrode for receiving the Bias signal Bias, and the drain is used as an output electrode connected to the gate of the first MOS transistor M1. Four timing control signals: the Row selection signal Row, the first driving signal OD _1, the Bias signal Bias, and the second driving signal OD _2 are respectively connected to the gate of the second MOS transistor M2, the gate and the source of the third MOS transistor M3, and the gate of the fourth MOS transistor M4. The connection relationship between the four MOS tubes and the ultrasonic sensor is as follows: on the basis of the three MOS tubes, the fourth MOS tube M4 is arranged between the first MOS tube M1 and the ultrasonic sensor. The fourth MOS tube M4 is connected with the third MOS tube M3 in series, the ultrasonic sensor is connected between the third MOS tube M3 and the fourth MOS tube M4, and the third MOS tube M3, the fourth MOS tube M4 and the fourth MOS tube M4 share one connection point. Specifically, the drain of the fourth MOS transistor M4 is connected to the gate of the first MOS transistor M1, and the source is connected to the ultrasonic sensor and the drain of the third MOS transistor M3.

In the embodiment where the four MOS transistors are P-type MOS transistors as illustrated in fig. 6E, the source of the second MOS transistor M2 is used as the input electrode connected to the gate of the first MOS transistor M1, and the drain is used as the output electrode for outputting the fingerprint peak signal. The drain of the third MOS transistor M3 is used as an input electrode for receiving the Bias signal Bias, and the source is used as an output electrode connected to the gate of the first MOS transistor M1. Four timing control signals: the Row selection signal Row, the first driving signal OD _1, the Bias signal Bias, and the second driving signal OD _2 are respectively connected to the gate of the second MOS transistor M2, the gate and the drain of the third MOS transistor M3, and the gate of the fourth MOS transistor M4. The connection relationship between the four MOS tubes and the ultrasonic sensor is as follows: the grid electrode of the first MOS tube M1 is connected with the source electrode of the fourth MOS tube M4, the drain electrode is connected with the source electrode of the second MOS tube M2, and the source electrode is connected with a constant-voltage direct-current power supply Vcc. The drain of the fourth MOS transistor M4 is connected to the ultrasonic sensor and the source of the third MOS transistor M3.

The ultrasonic fingerprint detection circuit 201a of the embodiment of the present specification includes only two electronic components, namely, a MOS transistor and a capacitor C1, and does not include other types of electronic components, such as a diode. Therefore, the function for raising the gate voltage or current of the first MOS transistor M1 needs to be performed by the MOS transistor. This requires the ability to do without a diode but still achieve a raised potential and also requires that the leakage be controlled to the same order as the diode leakage.

Based on the same inventive concept, the embodiment of the present specification further provides a fingerprint detection data sampling apparatus, as in the following embodiments. Because the principle of solving the problems of the fingerprint detection data sampling device is similar to that of the fingerprint detection data sampling method, the implementation of the fingerprint detection data sampling device can refer to the implementation of the fingerprint detection data sampling method, and repeated parts are not described again. As used hereinafter, the term "unit" or "module" may be a combination of software and/or hardware that implements a predetermined function. Although the means described in the embodiments below are preferably implemented in software, an implementation in hardware, or a combination of software and hardware is also possible and contemplated. Fig. 7 is a block diagram of a fingerprint detection data sampling apparatus according to an embodiment of the present disclosure, and as shown in fig. 7, the apparatus may include: the reset module 701, the first storage module 702, the processing module 703, the detection module 704, the output module 705, the second storage module 706, and the obtaining module 707 are described below.

The reset module 701 may be configured to reset the ultrasonic fingerprint detection circuit of each ultrasonic pixel unit in the ultrasonic pixel array, where the ultrasonic fingerprint detection circuit outputs a reset signal;

the first storage module 702 may be configured to turn on a first switch in the fingerprint detection data sampler corresponding to each ultrasonic pixel unit, and store the reset signal in the first capacitor;

a processing module 703, which can be used to provide an excitation signal to be applied to the ultrasonic pixel array, so that the ultrasonic pixel array generates an ultrasonic signal;

the detection module 704 can be used for the ultrasonic sensor in each ultrasonic pixel unit of the ultrasonic pixel array to provide the detected fingerprint electrical signal to the ultrasonic fingerprint detection circuit for detection;

the output module 705 can be used for providing a timing control signal to control the ultrasonic fingerprint detection circuit to perform fingerprint detection and output a fingerprint electrical signal;

the second storage module 706 may be configured to turn on a second switch in the fingerprint detection data sampler corresponding to each ultrasonic pixel unit, and store the fingerprint electrical signal in a second capacitor;

an obtaining module 707, configured to obtain fingerprint detection data corresponding to each ultrasound pixel unit; the fingerprint detection data is a difference value between a fingerprint electric signal and a reset signal output by a fingerprint detection data sampler connected with the ultrasonic pixel unit.

Referring to fig. 8, the present embodiment can provide a method for sampling fingerprint detection data by using the above fingerprint detection data samples. The fingerprint detection data sampling method may include the following steps.

S801: and providing an excitation signal, applying the excitation signal to the ultrasonic pixel array, and enabling the ultrasonic pixel array to generate an ultrasonic signal.

S802: the ultrasonic sensor in each ultrasonic pixel unit of the ultrasonic pixel array provides the detected fingerprint electric signal to the ultrasonic fingerprint detection circuit for detection.

S803: and providing a time sequence control signal to control the ultrasonic fingerprint detection circuit to perform fingerprint detection and output a fingerprint electric signal.

S804: and switching on a second switch in the fingerprint detection data sampler corresponding to each ultrasonic pixel unit, and storing the fingerprint electric signal into a second capacitor.

S805: and resetting the ultrasonic fingerprint detection circuit of each ultrasonic pixel unit in the ultrasonic pixel array, wherein the ultrasonic fingerprint detection circuit outputs a reset signal.

S806: and switching on a first switch in the fingerprint detection data sampler corresponding to each ultrasonic pixel unit, and storing the reset signal into a first capacitor.

S807: and acquiring a reset signal in the first capacitor and a fingerprint electric signal in the second capacitor corresponding to each ultrasonic pixel unit.

S808: and taking the difference value between the fingerprint electric signal in the second capacitor corresponding to each ultrasonic pixel unit and the reset signal in the first capacitor as fingerprint detection data corresponding to each ultrasonic pixel unit.

In this embodiment, an excitation signal may be provided and applied to the ultrasonic pixel array 2 for fingerprint detection, so as to output a fingerprint electrical signal. Then, a Vdb Reset voltage value with the same potential is given to all ultrasonic pixel units in the ultrasonic pixel array to perform Reset operation on the ultrasonic fingerprint detection circuit 201a of each ultrasonic pixel unit in the ultrasonic pixel array, and the ultrasonic fingerprint detection circuit 201a outputs a Reset signal, so that no correlation exists between the read Reset signal and a fingerprint electric signal.

In this embodiment, the fingerprint detection data sampler outputs the reset signal in the first capacitor and the fingerprint electrical signal in the second capacitor, so that the inhomogeneity caused by the process can be quantified and recorded, the noise of the pixel array can be analyzed subsequently, and data support is provided for the subsequent analysis work.

In the present embodiment, since the ultrasonic pixel cells 201 are independent of each other, timing control signals of the ultrasonic pixel cells 201 are also different. In some embodiments, the reset signal in the first capacitor and the fingerprint electrical signal in the second capacitor output by the fingerprint detection data sampler may be sequentially read in rows, and further, the IC may perform difference operation and amplification processing on the fingerprint electrical signal and the reset operation of each ultrasonic pixel unit, so as to obtain fingerprint detection data corresponding to each ultrasonic pixel unit. In some embodiments, the data output by the fingerprint detection data sampler may also be sequentially read in columns, and the specific reading manner may be determined according to actual row selection signals and actual column selection signals, which is not limited in this specification.

From the above description, it can be seen that the embodiments of the present specification achieve the following technical effects: an excitation signal can be provided firstly and applied to the ultrasonic pixel array, a time sequence control signal is provided to control the ultrasonic fingerprint detection circuit to carry out fingerprint detection, and the fingerprint electric signal is stored into the second capacitor by turning on the second switch in the fingerprint detection data sampler corresponding to each ultrasonic pixel unit. The ultrasonic fingerprint detection circuit of each ultrasonic pixel unit in the ultrasonic pixel array is Reset by giving all the ultrasonic pixel units in the ultrasonic pixel array a Vdb Reset voltage value with the same potential, and the ultrasonic fingerprint detection circuit outputs a Reset signal. The reset signal can be stored in the first capacitor by turning on the first switch in the fingerprint detection data sampler corresponding to each ultrasonic pixel unit, so that no correlation exists between the read reset signal and the fingerprint electric signal. Furthermore, the fingerprint detection data sampler can acquire the reset signal in the first capacitor and the fingerprint electrical signal in the second capacitor, and can perform difference operation and amplification processing on the fingerprint electrical signal and the reset operation of each ultrasonic pixel unit, so as to obtain the fingerprint detection data corresponding to each ultrasonic pixel unit. Therefore, errors related to the process can be effectively eliminated, and heterogeneity caused by the process can be quantified and recorded, so that the noise of the pixel array can be analyzed subsequently, and data support is provided for subsequent analysis work.

The above method is described below with reference to a specific embodiment, however, it should be noted that the specific embodiment is only for better describing the embodiment of the present specification and should not be construed as an improper limitation to the embodiment of the present specification. The method can comprise the following steps:

the voltage values of at least three sequential control signals are adjusted, so that the first MOS tube M1 stores fingerprint peak signals output by an ultrasonic sensor in a first preset time interval, the second MOS tube M2 outputs fingerprint peak signals stored in the first MOS tube M1 in a second preset time interval, the third MOS tube M3 resets grid signals of the first MOS tube M1 in a third preset time interval, and the direct current potential of the grid of the first MOS tube M1 is raised in the first preset time interval. In this embodiment, the storing of the fingerprint peak signal by the first MOS transistor M1 is completed within the same time interval as the raising of the dc potential of the gate thereof.

The voltage Δ V of the fingerprint peak signal is weak in general, and is difficult to be detected accurately. Therefore, in a further embodiment, the voltage values of at least three timing control signals within the first preset time interval may be adjusted, so that the first MOS transistor M1 stores the fingerprint peak signal output by the ultrasonic sensor, and the third MOS transistor M3 raises the dc potential signal of the gate of the first MOS transistor M1. In this embodiment, after the voltage boosting of the third MOS transistor M3, the voltage of the signal stored in the gate of the first MOS transistor M1 is converted from the voltage of the original fingerprint peak signal to the voltage of the fingerprint peak signal and the boosted value provided by the third MOS transistor M3.

Correspondingly, the voltage values of the at least three timing control signals in a second preset time interval are adjusted, so that the second MOS transistor M2 outputs a fingerprint peak signal stored in the first MOS transistor M1, and the third MOS transistor M3 raises a direct current potential signal of the grid electrode of the first MOS transistor M1. At this time, the voltage value of the signal output by the second MOS transistor M2 is the fingerprint signal voltage stored in the gate of the first MOS transistor M1 after boosting. Therefore, the voltage value of the output fingerprint electric signal is improved, and subsequent detection is facilitated.

Fig. 9 is a control timing diagram of the ultrasonic fingerprint detection circuit shown in fig. 6B to 6E, in the embodiment including four MOS transistors, each ultrasonic fingerprint detection circuit 201a receives four timing control signals (the first driving signal OD _1, the Bias signal Bias, the second driving signal OD _2, and the ROW selection signal ROW) independent of each other. In fig. 9, the horizontal axis represents TIME (TIME), the Excitation Signal represents an Excitation voltage Signal, and the Finger RX represents a Signal change of the ultrasonic field due to the intervention or disturbance of the user's Finger.

In order to avoid that external factors such as a user finger, an external environment and the like influence the fingerprint electric signal of the grid electrode of the first MOS tube M1 in the process that the second MOS tube M2 outputs the fingerprint electric signal in the second preset time interval, the voltage values of the four sequential control signals in the second preset time interval can be isolated by the fourth MOS tube M4 from the first MOS tube M1 and the ultrasonic sensor.

Therefore, in the second preset time interval, that is, in the process of reading or outputting the fingerprint electric signal, the fourth MOS transistor M4 is adopted to isolate the ultrasonic sensor, which may be interfered by external factors, from the first MOS transistor M1. Therefore, noise signals generated by the ultrasonic sensor are prevented from being transmitted to the grid electrode of the first MOS tube M1 due to the interference of the external environment, and the quality of the output fingerprint electric signals is improved.

Further, the third MOS transistor M3 outputs an electrical signal for resetting the gate of the first MOS transistor M1 through the fourth MOS transistor M4 in a third preset time interval and a fourth preset time interval under the four timing control signals. The third preset time interval and the fourth preset time interval respectively correspond to the time interval T1 and the time interval T5 in fig. 9, and may be named as a first reset time interval and a second reset time interval. That is, in this embodiment, the gate signal of the first MOS transistor M1 needs to be reset or reset twice. The reset of the gate potential of the first MOS transistor M1 in the third preset time interval may be a global reset, and the reset of the gate potential of the first MOS transistor M1 in the fourth preset time interval may be a local reset.

In a third predetermined time interval, the ROW selection signal ROW and the Bias signal Bias are at a low level, and the first driving signal OD _1 and the second driving signal OD _2 are at a high level. The second MOS tube M2 is turned off, and the third MOS tube M3 and the fourth MOS tube M4 are turned on. Since the fourth MOS transistor M4 is connected in series between the first MOS transistor M1 and the second MOS transistor M2, the fourth MOS transistor M4 at this time is equivalent to a wire. Therefore, the voltage of the gate of the first MOS transistor M1 can be reset to be equal to the voltage of the Bias signal Bias.

Similarly, if the Bias signal Bias is Reset voltage, the third MOS transistor M3 can Reset the gate of the first MOS transistor M1, and the fingerprint signal at the gate of the first MOS transistor M1 is cleared.

The first predetermined time interval corresponds to the time interval T2 in fig. 9. At this time, the ROW selection signal ROW is maintained at a low level, and the second MOS transistor M2 is in an off state. And the voltage value of the first driving signal OD _1 decreases to be equal to the voltage value of the Bias signal Bias. The third MOS transistor M3 forms a diode-like structure at this time.

Furthermore, the first driving signal and the bias signal each include a second boost pulse within a first preset time interval, the start time, the sustain time, and the voltage value of the two second boost pulses are the same, and the sustain time of the second boost pulse is T7. And the third MOS tube M3 raises the voltage signal of the grid electrode of the first MOS tube M1 under the action of the second boosting pulse, and the raised voltage of the grid electrode of the first MOS tube M1 is the sum of the voltage value of the fingerprint peak signal and the voltage value of the second boosting pulse.

Referring to fig. 9, in practice, at a certain time node within the first preset time interval, the ultrasonic sensor transmits back the fingerprint electrical signal. At this time, the first driving signal OD _1 and the Bias signal Bias generate a high pulse in a short time, i.e., a second boosting pulse. Since the third MOS transistor M3 is equivalent to a diode-like transistor in the whole first preset time interval, the voltage of the gate of the first MOS transistor M1 can be raised, and the raised voltage is maintained due to the unidirectional current limiting effect of the third MOS transistor M3 (diode-like transistor). Therefore, the grid voltage of the first MOS transistor M1 is raised from the fingerprint peak signal voltage Δ V to Vdc2+ Δ V, where Vdc2 is the voltage value of the second boost pulse of the Bias signal Bias.

The second predetermined time interval also includes two sub-time intervals, which respectively correspond to the sub-time interval T4 and the sub-time interval T6 in fig. 9, and may be named as a first reading time interval and a second reading time interval, respectively. In this embodiment, the fingerprint signal stored in the gate of the first MOS transistor M1 also needs to be read or output twice. Reading or outputting the boosted first MOS transistor M1 gate potential in the sub-time interval T4, and reading or outputting the reset signal after the first MOS transistor M1 gate is reset in the sub-time interval T6.

In the sub-time interval T4, the ROW selection signal ROW is at a high level, the second MOS transistor M2 is turned on, and the fingerprint electrical signal (specifically, the fingerprint electrical signal after voltage boosting, whose voltage value is the sum of the voltage value Δ V of the fingerprint peak signal and the voltage value Vdc2 of the second boost pulse) stored in the gate of the first MOS transistor M1 is output through the second MOS transistor M2.

In the process, in order to avoid the influence of the external factors, the fourth MOS transistor M4 is used to isolate the ultrasonic sensor, which may be interfered by the external factors, from the first MOS transistor M1. Specifically, the second driving signal OD _2 is at a low level, and the fourth MOS transistor M4 is turned off, so as to block the connection between the ultrasonic sensor and the first MOS transistor M1 and prevent the noise signal from being transmitted to the gate of the first MOS transistor M1. The third MOS transistor M3 is in an off state or an on state, which is not limited in this embodiment.

After the first reading is completed, a second reset or reset operation needs to be performed on the first MOS transistor M1. As shown in fig. 9, the time interval T5, i.e., the fourth preset time interval, is a secondary or local reset execution time period. In the time interval, the ROW selection signal ROW is at a low level, and the second MOS transistor M2 is turned off. The second driving signal OD _2 is at a high level, and the fourth MOS transistor M4 is turned on, which is equivalent to a conductive line. The first driving signal OD _1 switches to a high level, and the voltage value is greater than the voltage value of the Bias signal Bias. The voltage value of the Bias signal Bias at this time is slightly lower than the voltage value Vdc2 of the second boosting pulse. The third MOS transistor M3 is turned on, and the voltage of the gate of the first MOS transistor M1 is reset to be equal to the voltage value of the Bias signal Bias.

And then, adjusting the voltage values of the four timing control signals in a fifth preset time interval, so that the second MOS transistor M2 outputs an electric signal for resetting the gate of the first MOS transistor M1 by the third MOS transistor M3. The fifth predetermined time interval is the second reading time interval, which corresponds to the time interval T6 in fig. 9. That is, the electrical signal stored in the gate output by the second MOS transistor M2 in the fifth preset time interval is the electrical signal reset by the gate of the first MOS transistor M1 in the fourth preset time interval.

In the time interval, the voltage value of the first driving signal OD _1 is greater than the voltage value of the Bias signal Bias, and the third MOS transistor M3 is turned off. The ROW selection signal ROW is at a high level, and the second MOS transistor M2 is turned on, so as to output the voltage signal stored in the gate of the first MOS transistor M1. The voltage signal at this time is an electrical signal that the gate of the first MOS transistor M1 is reset within a fourth preset time interval, and is slightly smaller than the voltage value Vdc2 of the second boost pulse. Therefore, the voltage value Δ V of the fingerprint peak signal can be obtained by performing difference processing on the fingerprint electrical signal stored in the first MOS transistor M1 and output in the second preset time interval and the signal of the gate potential of the first MOS transistor M1 in the fourth preset time interval. Specifically, the voltage Vdc2+ Δ V of the superimposed fingerprint electrical signal output at the time of the first reading is subtracted by the reset voltage output after the second reset.

Through the secondary reset, the fingerprint electric signal which is output in the second preset time interval and stored in the first MOS tube M1 and the potential signal which is output in the fifth preset time interval and stored in the grid electrode of the first MOS tube M1 are subjected to difference processing, the influence of other factors on the fingerprint electric signal in the detection process can be filtered, and the bottom noise is reduced.

With reference to fig. 6B to 6E and fig. 9, in the embodiment including four MOS transistors, a specific process of completing sampling of a row of fingerprint detection data by the ultrasonic fingerprint detection sensor is as follows:

in a time interval T1 (a third preset time interval), the ROW selection signal ROW is at a low voltage, and the second MOS transistor M2 is turned off. The first driving signal OD _1 and the second driving signal OD _2 are at high level, the Bias signal Bias is at low voltage, the third MOS transistor M3 and the fourth MOS transistor M4 are connected, and the fourth MOS transistor M4 is equivalent to a wire. If the Bias signal Bias is Reset voltage, the third MOS transistor M3 performs Reset function to clear the fingerprint signal of the gate of the first MOS transistor M1.

In the time interval T2 (the first preset time interval), the ROW selection signal ROW is still maintained at the low level, and the second MOS transistor M2 is in the off state. The voltage value of the first driving signal OD _1 is decreased to be equal to the voltage value of the Bias signal Bias, and at this time, the third MOS transistor M3 forms a diode-like structure. While the ultrasonic sensor returns the fingerprint signal, the first driving signal OD _1 and the Bias signal Bias generate a second boost pulse for a short time. Since the third MOS transistor M3 functions as a diode-like transistor at this time, the voltage of the gate of the first MOS transistor M1 can be raised. Namely, the voltage of the grid electrode of the first MOS transistor M1 is raised to Vdc2+ delta V by the voltage delta V of the fingerprint peak signal, and the raised fingerprint peak signal is stored in the grid electrode of the first MOS transistor M1 to wait for subsequent output.

The time interval T3 is located before the first time reading time interval T4 according to the time sequence, and since the time for reading the data is long, in order to avoid the fingerprint electrical signal stored in the gate of the first MOS transistor M1 from being lost with time due to leakage, and to isolate the influence of external factors, the fourth MOS transistor M4 is turned off by reducing the potential of the second driving signal OD _2, so as to achieve the purpose of isolating the first MOS transistor M1 from the ultrasonic sensor.

In a time interval T4 (a first reading time interval included in a second preset time interval), the ROW selection signal ROW is switched to a high level, the second MOS transistor M2 is turned on, the fingerprint electrical signal stored in the gate of the first MOS transistor M1 after being raised by the voltage is output through the second MOS transistor M2, at this time, the second switch in the fingerprint detection data sampler corresponding to the ultrasonic pixel unit is turned on, and the fingerprint electrical signal output by the second MOS transistor M2 is stored in the second capacitor. In addition, in the process, the second driving signal OD _2 maintains a low level, and the fourth MOS transistor M4 maintains an off state, so as to block the connection between the ultrasonic sensor and the first MOS transistor M1 and prevent the noise signal from being transmitted to the gate of the first MOS transistor M1.

Subsequently, a secondary or local reset is performed. In the sub-time interval T5 (a fourth preset time interval), the ROW selection signal ROW is switched to a low level, and the second MOS transistor M2 is turned off. The second driving signal OD _2 is switched to a high level, and the fourth MOS transistor M4 is turned on, which is equivalent to a conductive line. The first driving signal OD _1 switches to a high level, and the voltage value is greater than the voltage value of the Bias signal Bias. The voltage value of the Bias signal Bias at this time is slightly lower than the voltage value Vdc2 of the second boosting pulse. The third MOS transistor M3 is turned on, and the voltage of the gate of the first MOS transistor M1 is reset to be equal to the voltage value of the Bias signal Bias.

Finally, a second reading is taken. In a time interval T6 (a fifth preset time interval), the voltage value of the first driving signal OD _1 is controlled to be greater than the voltage value of the Bias signal Bias, and the third MOS transistor M3 is turned off. And switching the ROW selection signal ROW to a high level to switch on the second MOS tube M2 and output a voltage signal stored in the grid electrode of the first MOS tube M1, wherein the voltage signal at the moment is a reset voltage signal Va, switching on a first switch in the fingerprint detection data sampler corresponding to the ultrasonic pixel unit, and storing the output reset signal into a first capacitor. The voltage value Vdc2+ Δ V of the fingerprint signal outputted during the time interval T4 may be differenced with the reset signal Va, and the finally obtained fingerprint detection data is the difference Vdc2+ Δ V-Va between the voltages outputted twice, which is closer to the actual fingerprint peak signal.

Further, as shown in fig. 6A to 6E, each ultrasonic fingerprint detection circuit 201a may further include a capacitor C1, where the capacitor C1 has two poles: a first pole and a second pole. The first electrode is connected with the grid electrode of the first MOS transistor M1. The capacitor C1 keeps the signal stored in the gate of the first MOS transistor M1 in a first predetermined time interval under at least three timing control signals. That is to say, when the second MOS transistor M2 is in the off state and the gate of the first MOS transistor M1 stores the fingerprint peak signal, the capacitor C1 is used to hold the fingerprint peak signal stored in the gate of the first MOS transistor M1, so as to reduce the loss of the fingerprint electrical signal during the storage process.

As shown in fig. 6B and fig. 6E, in a possible embodiment, the second pole of the capacitor C1 may be connected to a ROW selection signal ROW, and the voltage of the gate of the first MOS transistor M1 is raised by the ROW selection signal ROW.

However, as can be seen from the above, in the embodiment including four MOS transistors, since the time period (the time interval T3 shown in fig. 9) for the gate of the first MOS transistor M1 to hold the signal is not consistent with the time period (i.e., the second preset time interval, or the time interval T4 shown in fig. 9) for the ROW selection signal ROW to be turned on, the ROW selection signal ROW may not be able to function within the time period for the gate of the first MOS transistor M1 to hold the signal.

Therefore, as shown in fig. 6C, to solve the above problem, in another possible embodiment, the second pole of the capacitor C1 can be connected to a dc potential V2, and the voltage of the gate of the first MOS transistor M1 is directly raised by the dc potential V2.

Similarly, the voltage value of the dc potential V2 in this embodiment is difficult to determine, and if the voltage value of the dc potential V2 is too small, the gate voltage of the first MOS transistor M1 is not raised significantly. If the voltage value of the dc voltage V2 is too large, the voltage of the gate of the first MOS transistor M1 will be raised to a level that may overwrite the stored fingerprint signal. Therefore, the effect of this embodiment is difficult to control.

To further solve the above problem, in yet another possible embodiment, as shown in fig. 6A and 6D, the second pole of the capacitor C1 is selected to be grounded. In this embodiment, the capacitor C1 is grounded, so that the function of the capacitor C1 becomes pure and single, only the capacitor C1 holds the fingerprint signal stored in the gate of the first MOS transistor M1, and the function of raising the gate potential of the first MOS transistor M1 is performed by the third MOS transistor M3. Thus, a control signal can be reduced, and the control logic of the current is more clear and simple.

In the embodiment that the ultrasonic fingerprint detection circuit 201a includes four MOS transistors, by adjusting the timing control signal, it is possible to make this electronic component of fourth MOS transistor M4 realize two functions of signal reset and voltage raising to the gate of first MOS transistor M1, and the flexibility of the circuit is better.

In addition, fourth MOS pipe M4 can avoid basically not using the electric leakage problem that the first MOS pipe M1 grid that the diode triggered appears to can keep apart first MOS pipe M1 and ultrasonic sensor, avoid external factor's influence, the output of fingerprint signal of telecommunication or the reading process do not receive the influence of external noise factors such as finger or external world, guarantee the authenticity of the fingerprint detection data of output.

It should be noted that the high level and the low level are voltage thresholds for turning on and off the MOS transistor, respectively, and may be set according to actual situations, for example, the high level is 0 to 17V, further may be 0 to 15V, and the low level is 0V. The above explanation and numerical definition of the high and low levels are applicable to the on or off condition of all MOS transistors related to the present invention.

Based on the same inventive concept, the embodiment of the present specification further provides a fingerprint detection data sampling apparatus, as described in the following embodiments. Because the principle of the fingerprint detection data sampling device for solving the problems is similar to the fingerprint detection data sampling method, the implementation of the fingerprint detection data sampling device can refer to the implementation of the fingerprint detection data sampling method, and repeated parts are not repeated. As used hereinafter, the term "unit" or "module" may be a combination of software and/or hardware that implements a predetermined function. Although the means described in the embodiments below are preferably implemented in software, an implementation in hardware, or a combination of software and hardware is also possible and contemplated. Fig. 10 is a block diagram of a fingerprint detection data sampling apparatus according to an embodiment of the present disclosure, and as shown in fig. 10, the apparatus may include: the configuration of the first processing module 101, the detection module 102, the output module 103, the first storage module 104, the reset module 105, the second storage module 106, the acquisition module 107, and the second processing module 108 will be described below.

A first processing module 101, configured to provide an excitation signal to be applied to an ultrasound pixel array, so that the ultrasound pixel array generates an ultrasound signal;

the detection module 102 may be configured to provide, by the ultrasonic sensor in each ultrasonic pixel unit of the ultrasonic pixel array, the detected fingerprint electrical signal to the ultrasonic fingerprint detection circuit for detection;

the output module 103 may be configured to provide a timing control signal to control the ultrasonic fingerprint detection circuit to perform fingerprint detection, and output a fingerprint electrical signal;

the first storage module 104 may be configured to turn on a second switch in the fingerprint detection data sampler corresponding to each ultrasonic pixel unit, and store the fingerprint electrical signal in a second capacitor;

a reset module 105, configured to perform a reset operation on an ultrasonic fingerprint detection circuit of each ultrasonic pixel unit in the ultrasonic pixel array, where the ultrasonic fingerprint detection circuit outputs a reset signal;

the second storage module 106 may be configured to turn on the first switch in the fingerprint detection data sampler corresponding to each ultrasonic pixel unit, and store the reset signal in the first capacitor;

an obtaining module 107, configured to obtain a reset signal in a first capacitor and a fingerprint electrical signal in a second capacitor corresponding to each ultrasonic pixel unit;

the second processing module 108 may be configured to use a difference between the fingerprint electrical signal in the second capacitor corresponding to each ultrasonic pixel unit and the reset signal in the first capacitor as fingerprint detection data corresponding to each ultrasonic pixel unit.

It should be noted that, in the description of the present invention, the terms "first", "second", and the like are used for descriptive purposes only and for distinguishing similar objects, and no precedence between the two is considered as indicating or implying relative importance. In addition, in the description of the present invention, "a plurality" means two or more unless otherwise specified.

It should be apparent to those skilled in the art that the modules or steps of the embodiments of the present specification described above can be implemented by a general purpose computing device, they can be centralized in a single computing device or distributed over a network of multiple computing devices, and alternatively, they can be implemented by program code executable by a computing device, so that they can be stored in a storage device and executed by a computing device, and in some cases, the steps shown or described can be executed in a different order therefrom, or they can be separately fabricated as individual integrated circuit modules, or multiple modules or steps therein can be fabricated as a single integrated circuit module. Thus, embodiments of the present description are not limited to any specific combination of hardware and software.

Although the embodiments herein provide the method steps as described in the above embodiments or flowcharts, more or fewer steps may be included in the method based on conventional or non-inventive efforts. In the case of steps where no causal relationship is logically necessary, the order of execution of the steps is not limited to that provided by the embodiments of the present description. When implemented in an actual apparatus or end product, the methods described herein may be performed sequentially or in parallel according to embodiments or methods shown in the figures (e.g., in the context of parallel processors or multi-threaded processing).

It is to be understood that the above description is intended to be illustrative, and not restrictive. Many embodiments and many applications other than the examples provided will be apparent to those of skill in the art upon reading the above description. The scope of embodiments of the present specification should, therefore, be determined not with reference to the above description, but should instead be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

The above description is only a preferred embodiment of the embodiments of the present disclosure, and is not intended to limit the embodiments of the present disclosure, and it will be apparent to those skilled in the art that various modifications and variations can be made in the embodiments of the present disclosure. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the embodiments of the present disclosure should be included in the protection scope of the embodiments of the present disclosure.

Claims

1. A fingerprint sensing data sampler, wherein each fingerprint sensing data sampler is electrically connected to an ultrasonic pixel cell in an ultrasonic pixel array, the ultrasonic pixel cell comprising: ultrasonic sensor, with ultrasonic sensor electric connection's ultrasonic fingerprint detection circuit, ultrasonic fingerprint detection circuit is based on the chronogenesis control signal output fingerprint signal of telecommunication of receipt, fingerprint detection data sample thief includes:

the first capacitor is electrically connected with the first switch; a reset signal is stored in the first capacitor by turning on the first switch; the reset signal is a potential signal output by resetting the ultrasonic fingerprint detection circuit;

the second capacitor is electrically connected with the second switch; a fingerprint electric signal is stored in the second capacitor by turning on the second switch; the first switch and the second switch are electrically connected with the output end of the ultrasonic fingerprint detection circuit;

the processing unit is used for reading the reset signal in the first capacitor and the fingerprint electric signal in the second capacitor and determining the difference value between the fingerprint electric signal and the reset signal; wherein, the difference value of the fingerprint electric signal and the reset signal is fingerprint detection data corresponding to the ultrasonic wave pixel unit.

2. The fingerprint detection data sampler of claim 1, wherein the first switch is in parallel with the second switch, and wherein the first switch and the second switch are not conductive at the same time.

3. The fingerprint detection data sampler of claim 1, wherein the first switch is in series with the first capacitor and the second switch is in series with the second capacitor.

4. The fingerprint detection data sampler of claim 1, wherein the processing unit comprises a switched capacitor differential amplifier configured to output a difference between the fingerprint electrical signal and the reset signal.

5. The fingerprint detection data sampler of claim 4, wherein the switched capacitor differential amplifier comprises two inputs electrically connected to the first capacitor and the second capacitor, respectively.

6. A fingerprint detection data sampling method, comprising:

resetting an ultrasonic fingerprint detection circuit of each ultrasonic pixel unit in the ultrasonic pixel array, wherein the ultrasonic fingerprint detection circuit outputs a reset signal;

switching on a first switch in the fingerprint detection data sampler corresponding to each ultrasonic pixel unit, and storing the reset signal into a first capacitor;

providing an excitation signal, applying the excitation signal to the ultrasonic pixel array to enable the ultrasonic pixel array to generate an ultrasonic signal;

an ultrasonic sensor in each ultrasonic pixel unit of the ultrasonic pixel array provides a detected fingerprint electric signal to the ultrasonic fingerprint detection circuit for detection;

providing a time sequence control signal to control the ultrasonic fingerprint detection circuit to perform fingerprint detection and output a fingerprint electric signal;

switching on a second switch in the fingerprint detection data sampler corresponding to each ultrasonic pixel unit, and storing the fingerprint electric signal into a second capacitor;

acquiring fingerprint detection data corresponding to each ultrasonic pixel unit; the fingerprint detection data is a difference value between a fingerprint electric signal and a reset signal output by a fingerprint detection data sampler connected with the ultrasonic pixel unit.

7. The method of claim 6, further comprising, prior to acquiring fingerprint detection data corresponding to each ultrasound pixel element:

and controlling the reset signal in the first capacitor and the fingerprint electric signal in the second capacitor to be respectively input into the switched capacitor differential amplifier, wherein the switched capacitor differential amplifier comprises two input ends, and obtaining the difference value between the fingerprint electric signal and the reset signal.

8. A fingerprint sensing data sampling apparatus, comprising:

the ultrasonic fingerprint detection circuit comprises a reset module, a detection module and a control module, wherein the reset module is used for resetting the ultrasonic fingerprint detection circuit of each ultrasonic pixel unit in the ultrasonic pixel array, and the ultrasonic fingerprint detection circuit outputs a reset signal;

the first storage module is used for conducting a first switch in the fingerprint detection data sampler corresponding to each ultrasonic pixel unit and storing the reset signal into a first capacitor;

the processing module is used for providing an excitation signal, and applying the excitation signal to the ultrasonic pixel array so as to enable the ultrasonic pixel array to generate an ultrasonic signal;

the detection module is used for providing a detected fingerprint electric signal to the ultrasonic fingerprint detection circuit for detection by the ultrasonic sensor in each ultrasonic pixel unit of the ultrasonic pixel array;

the output module is used for providing a time sequence control signal to control the ultrasonic fingerprint detection circuit to carry out fingerprint detection and output a fingerprint electric signal;

the second storage module is used for conducting a second switch in the fingerprint detection data sampler corresponding to each ultrasonic pixel unit and storing the fingerprint electric signal into a second capacitor;

the acquisition module is used for acquiring fingerprint detection data corresponding to each ultrasonic pixel unit; the fingerprint detection data is a difference value between a fingerprint electric signal and a reset signal output by a fingerprint detection data sampler connected with the ultrasonic pixel unit.

9. A fingerprint detection data sampling method, comprising:

providing an excitation signal, applying the excitation signal to an ultrasonic pixel array to enable the ultrasonic pixel array to generate an ultrasonic signal;

an ultrasonic sensor in each ultrasonic pixel unit of the ultrasonic pixel array provides a detected fingerprint electric signal to an ultrasonic fingerprint detection circuit for detection;

resetting the ultrasonic fingerprint detection circuit of each ultrasonic pixel unit in the ultrasonic pixel array, wherein the ultrasonic fingerprint detection circuit outputs a reset signal;

acquiring a reset signal in a first capacitor and a fingerprint electric signal in a second capacitor corresponding to each ultrasonic pixel unit;

and taking the difference value between the fingerprint electric signal in the second capacitor corresponding to each ultrasonic pixel unit and the reset signal in the first capacitor as fingerprint detection data corresponding to each ultrasonic pixel unit.

10. A fingerprint sensing data sampling apparatus, comprising:

the first processing module is used for providing an excitation signal, and applying the excitation signal to the ultrasonic pixel array so as to enable the ultrasonic pixel array to generate an ultrasonic signal;

the detection module is used for providing the detected fingerprint electrical signal to the ultrasonic fingerprint detection circuit for detection by the ultrasonic sensor in each ultrasonic pixel unit of the ultrasonic pixel array;

the first storage module is used for conducting a second switch in the fingerprint detection data sampler corresponding to each ultrasonic pixel unit and storing the fingerprint electric signal into a second capacitor;

the ultrasonic fingerprint detection circuit is used for detecting the ultrasonic fingerprint of each ultrasonic pixel unit in the ultrasonic pixel array;

the second storage module is used for conducting the first switches in the fingerprint detection data samplers corresponding to the ultrasonic pixel units and storing the reset signals into the first capacitors;

the acquisition module is used for acquiring a reset signal in the first capacitor and a fingerprint electric signal in the second capacitor corresponding to each ultrasonic pixel unit;

and the second processing module is used for taking the difference value between the fingerprint electric signal in the second capacitor corresponding to each ultrasonic pixel unit and the reset signal in the first capacitor as fingerprint detection data corresponding to each ultrasonic pixel unit.