Fingerprint sensor, fingerprint identification device and fingerprint identification method

Abstract

The embodiments of this specification disclose a fingerprint sensor, a fingerprint recognition device, and a fingerprint recognition method. The fingerprint sensor may include a coding mask layer and a photosensitive layer. The coding mask layer includes a plurality of light-transmitting holes and opaque areas between the light-transmitting holes. The photosensitive layer is used to receive the light signal that is reflected by the target object and passes through the light-transmitting holes of the coding mask layer, and convert the received light signal into an electrical signal, so that the processor connected to the fingerprint sensor processes the electrical signal according to the arrangement of the light-transmitting holes and the opaque areas of the coding mask layer to obtain the fingerprint information of the target object. By using the various embodiments of this specification, the manufacturing process can be greatly simplified, and the applicability of the fingerprint sensor can also be improved.

Description

Technical Field

[0001] The present specification relates to the field of biometric information detection technology, and in particular, to a fingerprint sensor, a fingerprint recognition device, and a fingerprint recognition method. Background Art

[0002] Optical fingerprint sensors are widely used in electronic products such as mobile phones and laptops. Usually, such devices tend to pursue smaller, lighter and cheaper fingerprint sensors. At present, fingerprint sensors for such devices generally use micro-lens arrays or fiber collimators instead of traditional lens modules to achieve thin and light optical fingerprint modules. However, the process difficulty of micro-lens arrays or collimation structures is relatively high, and the manufacturing cost is also high. In addition, their field of view, resolution and light capture efficiency are limited by the size of the micro-lens or collimation holes, and the requirements for the external environment are also high. For example, fingerprint sensors using the above structure usually require strong external light and a relatively accurate fingerprint recovery algorithm to ensure the accuracy of fingerprint information recovery. Therefore, there is an urgent need for a fingerprint recognition device that is simpler and more convenient to manufacture and more adaptable to the external environment. Summary of the invention

[0003] The purpose of the embodiments of this specification is to provide a fingerprint sensor, a fingerprint recognition device and a fingerprint recognition method, which can greatly simplify the manufacturing process of the fingerprint sensor and improve the applicability of the fingerprint sensor.

[0004] This specification provides a fingerprint sensor, a fingerprint recognition device, and a fingerprint recognition method that are implemented in the following ways:

[0005] A fingerprint sensor, comprising: a coding mask layer and a photosensitive layer;

[0006] The coding mask layer includes a plurality of light-transmitting holes and a light-impermeable area between the light-transmitting holes;

[0007] The photosensitive layer is used to receive the light signal that is reflected by the target object and passes through the light-transmitting holes of the coding mask layer, and convert the received light signal into an electrical signal, so that the processor connected to the fingerprint sensor processes the electrical signal according to the layout of the light-transmitting holes and the opaque areas of the coding mask layer to obtain the fingerprint information of the target object.

[0008] In some other embodiments of the fingerprint sensor provided in this specification, the sizes and / or positions of the light-transmitting holes on the encoding mask layer are arranged in a random manner.

[0009] In some other embodiments of the fingerprint sensor provided in this specification, the light-transmitting holes on the encoding mask layer are arranged according to a preset encoding rule, so that the optical signals corresponding to the respective light-transmitting holes received by the photosensitive layer are orthogonal and incoherent to each other.

[0010] In some other embodiments of the fingerprint sensor provided in this specification, the light-transmitting holes of the encoding mask layer are arranged in the following manner;

[0011] Divide the two-dimensional plane defined by the size range of the encoding mask layer into m×m encoding units, and calculate the values of each encoding unit using the following encoding model. The encoding units with a value of 1 are set to be light-transmitting, and the encoding units with a value of 0 are set to be light-blocking:

[0012]

[0013] where M ij is the value of the encoding unit in the i-th row and j-th column, and n is any positive integer greater than or equal to 1 and less than or equal to m;

[0014] Configure the encoding rule according to the correspondence between the values of each encoding unit and light-transmitting / light-blocking, and arrange the light-transmitting holes of the encoding mask layer using the configured encoding rule.

[0015] In some other embodiments of the fingerprint sensor provided in this specification, the encoding unit is rectangular.

[0016] In some other embodiments of the fingerprint sensor provided in this specification, the side length of the encoding unit is any value between 2 and 5 micrometers.

[0017] In some other embodiments of the fingerprint sensor provided in this specification, the value of m is a prime number between 500 < m < 5000.

[0018] In some other embodiments of the fingerprint sensor provided in this specification, a filter film is further covered on the encoding mask layer to allow light of a specified wavelength band to pass through.

[0019] In some other embodiments of the fingerprint sensor provided in this specification, the encoding mask layer includes a light-transmitting layer and an encoding layer; the light-transmitting layer is arranged close to the photosensitive layer, and the encoding layer is arranged far from the photosensitive layer; the encoding layer includes a plurality of light-transmitting holes and light-blocking regions between the respective light-transmitting holes.

[0020] On the other hand, an embodiment of this specification further provides a fingerprint recognition device, which includes: an optical cover plate;

[0021] A display located inside the optical cover plate;

[0022] A fingerprint sensor as described in any one or more of the above embodiments; the fingerprint sensor is arranged on a side of the display away from the optical cover plate; wherein the encoding mask layer of the fingerprint sensor is arranged close to the display, and the photosensitive layer is arranged away from the display;

[0023] The fingerprint sensor is electrically connected to the processor; the processor is used to receive the electrical signal sent by the fingerprint sensor, and process the electrical signal based on the layout of the light-transmitting holes and the opaque areas of the coding mask layer to obtain fingerprint information.

[0024] On the other hand, the embodiments of this specification also provide a fingerprint recognition method based on the fingerprint recognition device described in the above embodiments, the method comprising:

[0025] The photosensitive layer of the fingerprint sensor collects the light signal reflected by the target object placed on the optical cover, converts the light signal into an electrical signal, and transmits it to the processor;

[0026] The processor receives the electrical signal and obtains the fingerprint information of the target object in the following manner:

[0027] Performing filtering processing on the electrical signal;

[0028] The filtered electrical signal is processed based on the arrangement of the light-transmitting holes and the opaque areas of the encoding mask layer of the fingerprint sensor to obtain the fingerprint information of the target object.

[0029] The fingerprint sensor, fingerprint recognition device and fingerprint recognition method provided by one or more embodiments of this specification, by laying out a coding mask layer, encodes and processes the light reflected from the target object using the arrangement of the light-transmitting holes and the opaque areas on the coding mask layer, so that the light signal collected by the photosensitive layer is associated with the arrangement of the light-transmitting holes and the opaque areas on the coding mask layer. Thus, the information collected by the photosensitive layer can be processed based on the arrangement of the light-transmitting holes and the opaque areas on the coding mask layer, and the fingerprint information of the target object can be accurately and efficiently restored. The recovery of fingerprint information by coding has relatively low requirements on the quality of the information collected by the photosensitive layer, and even under weak external light, a good fingerprint information recovery effect can still be obtained, thereby greatly improving the applicable scenarios of the fingerprint sensor. In addition, the manufacturing process of the coding mask layer is simpler, which can greatly reduce the manufacturing process cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of this specification or the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art description. Obviously, the drawings described below are only some embodiments recorded in this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. In the drawings:

[0031] Figure 1 A schematic diagram of the structure of a fingerprint sensor provided in this specification;

[0032] Figure 2 A schematic diagram of fingerprint recognition based on a fingerprint sensor in an embodiment provided in this specification;

[0033] Figure 3 A schematic diagram of coding unit values ​​in another embodiment provided in this specification;

[0034] Figure 4 A schematic diagram of the layout of the encoding mask layer of a fingerprint sensor in another embodiment provided in this specification;

[0035] Figure 5 A schematic flow chart of a fingerprint recognition method in another embodiment provided in this specification;

[0036] Figure 6 This is a flowchart of a fingerprint recognition method in another embodiment provided in this specification. DETAILED DESCRIPTION

[0037] In order to enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in one or more embodiments of this specification will be clearly and completely described below in conjunction with the drawings in one or more embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of the specification, not all of the embodiments. Based on one or more embodiments of the specification, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the embodiments of this specification.

[0038] The fingerprint sensor provided in the embodiments of this specification can further simplify the structure of the sensor, reduce the requirements for the external environment, improve the simplicity of design, and reduce the design cost. Figure 1 Schematic diagram of the structure of a fingerprint sensor provided by an embodiment of this specification. Figure 1 As shown, in some embodiments, the fingerprint sensor includes an encoding mask layer 101 and a photosensitive layer 102.

[0039] The coding mask layer 101 may include a plurality of light-transmitting holes and a light-impermeable region between the light-transmitting holes.

[0040] The photosensitive layer 102 can be used to receive light signals that are reflected by the target object and pass through the light-transmitting holes of the coding mask layer, and convert the received light signals into electrical signals, so that a processor connected to the fingerprint sensor processes the electrical signals according to the layout of the light-transmitting holes and the opaque areas of the coding mask layer to obtain the fingerprint information of the target object.

[0041] The light-transmitting hole of the coding mask layer 101 may be circular or any polygonal. The filler in the light-transmitting hole may be air; or it may be filled with a medium, such as a transparent photoresist. The light transmittance of the filler of the light-transmitting hole may be set to be greater than the first preset value; or, the light transmittance of the filler only for light in a specified band may be greater than the first preset value, and the light transmittance for light other than the specified band may be less than the second preset value. The material of the opaque area may be an optical material with a light transmittance less than a third preset value. The material of the opaque area may be a light-absorbing material, such as black glue, to minimize the light signal passing through the opaque area. The smaller the third preset value is set, the better. The first preset value may be a value greater than 90%, and the second preset value and the third preset value may be values ​​less than 10%. The size of the first preset value, the second preset value, and the third preset value may also be set according to actual needs.

[0042] The photosensitive layer 102 may be composed of components that convert light signals into electrical signals. The components may be photodiodes, etc. The photosensitive layer 102 may be composed of a plurality of components arranged in an array.

[0043] The coding mask layer can be arranged on one side of the photosensitive layer so that the light reflected by the target object passes through the light-transmitting hole of the coding mask layer and is incident on the photosensitive layer. The coding mask layer can be fixed on the photosensitive layer by means of gluing or the like. Alternatively, the coding mask layer can also be fixed on other components, such as the inner side of a display. The target object can be, for example, a human finger, or a two-dimensional or three-dimensional fingerprint image.

[0044] In some implementations, the fingerprint sensor can be integrated into a fingerprint recognition device such as a mobile phone, a tablet computer, or a dedicated fingerprint recognition device to recognize the user's fingerprint information and verify the user's fingerprint information. The fingerprint sensor can be integrated below the display of the fingerprint recognition device, with the encoding mask layer of the fingerprint sensor arranged close to the display and the photosensitive layer arranged away from the display.

[0045] like Figure 2As shown, the user can place the fingerprint of the finger on the optical cover plate 201 of the fingerprint recognition device. The light emitted by the display to the optical cover plate is reflected by the fingerprint of the finger placed on the optical cover plate, and the reflected light formed after the reflection passes through the light-transmitting hole of the coding mask layer 202 of the fingerprint sensor, and then enters the photosensitive layer 203 of the fingerprint sensor. According to the principle that the light field propagates in a straight line, the reflected light carrying the fingerprint information passes through the coding mask layer to form two-dimensional projection information on the photosensitive layer. Then, the photosensitive layer converts the received two-dimensional projection information into an electrical signal for output. After the light passes through the coding mask layer, there is a certain correlation between the light information formed on the two-dimensional image plane and the layout of the light-transmitting holes and the opaque areas of the coding mask layer. Accordingly, the fingerprint information of the finger fingerprint on the optical cover plate can be restored using the light information of the image plane and the correlation.

[0046] In some embodiments, after the light passes through the coding mask layer, the light intensity distribution function Y of the light signal received on the photosensitive layer can be expressed as the convolution of the two-dimensional light intensity distribution function X of the reflected light on the object plane where the target object is located and the coding function M corresponding to different arrangements of the light-transmitting holes and the opaque areas of the coding mask layer:

[0047]

[0048] Among them, (u, v) is the two-dimensional coordinate of the object plane where the target object is located, (s, t) is the two-dimensional coordinate of the image plane where the photosensitive layer is located, m1 and m2 are the two-dimensional coordinates of the coding mask layer, Among them, f1 and f2 are the distance between the object plane where the target object is located and the coding mask layer, and the distance between the coding mask layer and the photosensitive layer, respectively, and Noise is a constant.

[0049] After the photosensitive layer converts the received optical signal into an electrical signal, it can be transmitted to the processor. The processor can process the received electrical signal based on the coding function M to restore the fingerprint information of the target object on the optical cover. In some embodiments, the processor can use the sample data to determine the coding function M corresponding to the coding mask layer of the fingerprint sensor in advance, and then use the determined coding function M to perform fingerprint information recovery processing on the signal collected by the photosensitive layer to restore the fingerprint information.

[0050] In some embodiments, the light-transmitting holes of the coding mask layer may be arranged in a periodic manner. The periodic manner may mean that the light-transmitting holes on the coding mask layer have the same size and are arranged in a certain period. By adopting a periodic arrangement, the arrangement of the light-transmitting holes and the opaque areas of the coding mask layer can be simpler, more convenient, and easier to process. In other embodiments, the light-transmitting holes of the coding mask layer may be arranged in a random manner. The random manner may mean that the size and position of the light-transmitting holes on the coding mask layer are random. By arranging the coding mask layer in a random manner, the design of the fingerprint sensor can be made more flexible. At the same time, based on the random arrangement, the coding methods of different sensor devices can also be different to a certain extent, further improving the anti-counterfeiting function of user fingerprint information verification.

[0051] Compared with the existing method of arranging collimating elements on the photosensitive layer or arranging collimating elements on the display, the manufacturing process of the fingerprint sensor provided in the embodiment of this specification is simpler, and at the same time, the thickness of the device integrated with the fingerprint sensor can be greatly reduced. At the same time, there is a certain correlation between the light signal received by the photosensitive layer and the arrangement of the light-transmitting holes and the opaque holes of the coding mask layer. Therefore, the correlation can be simply and conveniently used to realize the accurate recovery of fingerprint information.

[0052] The information collected by each sensor element in the existing fingerprint sensor based on the collimating element usually needs to be restored by splicing. The information splicing method has high requirements on the quality of the information collected by each sensor element. Therefore, it is necessary to optimize the layout of the collimating element and the light intensity, etc., to ensure the accuracy of the final verification result. However, the embodiment of this specification recovers the fingerprint information by encoding, and the quality requirements for the information collected by the photosensitive layer are relatively low. Even in low light or with some noise, a good recovery effect can still be obtained, thereby further reducing the requirements for the external environment during the fingerprint information verification process and improving the applicability of the fingerprint sensor.

[0053] In other embodiments, the light-transmitting holes on the coding mask layer can be arranged using a preset coding rule so that the light signals corresponding to the light-transmitting holes received by the photosensitive layer are orthogonal and incoherent. By designing the coding mask layer in this way, the two-dimensional light intensity distribution function corresponding to the light signal received by the photosensitive layer can be further decomposed into two groups of incoherent one-dimensional intensity distribution functions. Accordingly, the relationship between the light intensity distribution function Y of the light signal received on the photosensitive layer and the two-dimensional light intensity distribution function X of the reflected light on the object plane where the fingerprint is located can be further expressed as:

[0054]

[0055] The solution of the encoding function M can be converted into {Po ,Q O ,P C ,Q C}. O ,Q O ,P C ,Q C} is a one-dimensional array, which can greatly simplify the solution calculation.

[0056] In some embodiments, the light-transmitting holes of the coding mask layer may be arranged in the following manner so that the information corresponding to each light-transmitting hole collected by the photosensitive layer is orthogonal and irrelevant:

[0057] The two-dimensional plane defined by the size range of the coding mask layer is divided into m×m coding units. The value of each coding unit is calculated using the following coding model. The coding unit with a value of 1 is set to be light-transmitting, and the coding unit with a value of 0 is set to be opaque:

[0058]

[0059] Among them, M ij The value of the coding unit in the i-th row and j-th column, where n is any positive integer greater than or equal to 1 and less than or equal to m. Figure 3 As shown, Figure 3 Represents a matrix consisting of the values ​​of 25*25 coding units.

[0060] Then, the coding rules can be configured according to the corresponding relationship between the values ​​of each coding unit and the light-transmitting and light-opaque areas, and the light-transmitting holes of the coding mask layer can be arranged using the configured coding rules. By adopting the above coding model to design the light-transmitting holes and the light-opaque areas of the coding mask layer, it can be more simple and efficient to achieve orthogonal incoherence between the information corresponding to each light-transmitting hole collected by the photosensitive layer.

[0061] In some embodiments, the coding unit may be a rectangle. Accordingly, the coding mask layer may be a rectangular unit array composed of light-transmitting holes and light-impermeable holes. Figure 4 As shown, Figure 4 The black rectangular units in the image are opaque holes, and the white rectangular units are light-transmitting holes. By configuring the coding mask layer with rectangular light-transmitting holes, the edge features of the information corresponding to each light-transmitting hole collected by the photosensitive layer can be made more obvious, thereby making it easier to distinguish the information passing through the light-transmitting holes, thereby improving the accuracy of the fingerprint information finally recovered. In other embodiments, the coding unit can also be circular or in other shapes.

[0062] The size of the encoding unit and the value of m can be comprehensively configured according to the overall size of the sensor unit, the amount of data processing, the accuracy of fingerprint restoration, etc. Preferably, in some embodiments, the side length of the encoding unit can be any value between 2 and 5 micrometers. The value of m is a prime number between 500 < m < 5000. Based on the value of m within this range and the design of the encoding unit size, it is possible to effectively reduce the computational amount of fingerprint information restoration processing while ensuring the accuracy of the finally restored fingerprint information, and improve the efficiency of data processing.

[0063] In some embodiments, the encoding mask layer may include a light-transmitting layer and an encoding layer. The light-transmitting layer may be disposed close to the photosensitive layer. The encoding layer may be disposed away from the photosensitive layer. The encoding layer may include a plurality of light-transmitting holes and opaque regions located between the light-transmitting holes. Of course, it is also possible to arrange the encoding layer close to the photosensitive layer and the light-transmitting layer away from the photosensitive layer.

[0064] The light-transmitting layer may be an optical film with an optical transmittance greater than a first preset value. The material of the optical film can be set according to actual needs. For example, it can be a transparent photoresist, etc. The optical film may have the same or approximate transmittance for light of all bands; it may also have a transmittance greater than the first preset value only for light of a specified band and a transmittance less than a second preset value for light other than the specified band.

[0065] In some embodiments, an opaque layer may be first covered on the light-transmitting layer, and then, based on a preset encoding rule, part of the opaque material on the opaque layer may be removed by means of photolithography or the like to form the encoding mask layer. Of course, other methods may also be used to fabricate the encoding mask layer, which is not limited here.

[0066] In some other embodiments, the encoding mask layer may also only include the encoding layer, that is, the light-transmitting layer may be air.

[0067] In some embodiments, a filter film is further covered on the encoding mask layer to allow light of a specified band to pass through. For example, a filter film may be covered in the direction of the encoding mask layer close to the display to allow light of a specified band to pass through. The filter film may be, for example, an optical film that allows a certain preset band to pass through, or an optical film that filters a certain preset band and allows other bands except the preset band to transmit light.

[0068] Based on the fingerprint sensor provided in the above embodiments, in some other embodiments of this specification, a fingerprint recognition device using the fingerprint sensor is also provided. The fingerprint recognition device may be, for example, a mobile phone, a tablet computer, a smart watch, a fingerprint recognition device, etc. that can implement fingerprint recognition functions. The fingerprint sensor may be integrated into the above fingerprint recognition device. In some embodiments, the fingerprint recognition device may include:

[0069] Optical cover.

[0070] A display is located inside the optical cover.

[0071] A fingerprint sensor as described in any one or more of the above embodiments. The fingerprint sensor is arranged on a side of the display away from the optical cover. The encoding mask layer of the fingerprint sensor is arranged close to the display, and the photosensitive layer is arranged away from the display.

[0072] A processor is electrically connected to the fingerprint sensor. The processor is used to receive the electrical signal sent by the fingerprint sensor, and process the electrical signal based on the layout of the light-transmitting holes and the opaque areas of the coding mask layer to obtain fingerprint information.

[0073] like Figure 5 As shown, the embodiment of this specification also provides a fingerprint recognition method applied to the fingerprint recognition device, and the method may include:

[0074] S502: The photosensitive layer of the fingerprint sensor collects the light signal reflected by the target object placed on the optical cover, converts the light signal into an electrical signal, and transmits the electrical signal to the processor.

[0075] S504: The processor receives the electrical signal and obtains the fingerprint information of the target fingerprint in the following manner:

[0076] S5042: Filter the electrical signal;

[0077] S5044: Process the filtered electrical signal using the arrangement of the light-transmitting holes and the opaque areas of the encoding mask layer of the fingerprint sensor to obtain fingerprint information of the target fingerprint.

[0078] like Figure 6 As shown, a standard fingerprint can be obtained as a fingerprint sample, and then the fingerprint sample can be divided into a training set and a test set. For each fingerprint sample in the training set, the fingerprint recognition device provided by the above embodiment can be used to collect information to obtain the collection information corresponding to the corresponding fingerprint sample.

[0079] Then, the collected information can be preprocessed. For example, the PCA algorithm can be used to remove bad pixels in the original collected information in the training set. For example, bad pixels caused by fingerprints or stains on the screen, bubbles in the glue layer, etc. can be removed to improve the accuracy of subsequent fingerprint recovery.

[0080] Then, the pre-processed information may be filtered, for example, using Fourier transform (FFT) or discrete cosine transform (DCT).

[0081] Afterwards, the information corresponding to the standard fingerprint and the information after filtering can be processed by a preset algorithm to solve the coding function M corresponding to the coding mask layer. In some embodiments, when the coding mask layer is designed so that the information corresponding to each light-transmitting hole collected by the photosensitive layer is orthogonal and incoherent, the solution process of the above coding function can be converted into solving {P o ,Q o ,P C ,Q C}, thereby further simplifying the amount of calculation. In some embodiments, preferably, the preset algorithm may be a regularized least squares method.

[0082] Then, the test set can be used to test and optimize the algorithm. For the fingerprint samples in the test set, the above preprocessing and filtering steps can be repeated, and then the information after filtering can be restored by using the encoding function determined in the above manner to obtain the restored fingerprint information. Then, the restored fingerprint information can be compared with the corresponding fingerprint sample to evaluate the algorithm effect and adjust the algorithm parameters.

[0083] In practical applications, such as Figure 6 As shown, the processor can use the fingerprint recovery algorithm constructed in the above manner to determine the encoding function, and use the determined encoding function to process the collected information corresponding to the target object to restore the fingerprint information corresponding to the target object. After that, the fingerprint information template set of the corresponding user stored in advance can also be obtained, and the restored fingerprint information is compared with the fingerprint information template set to realize the fingerprint information verification of the user. If the verification is successful, the associated application is started, such as opening the lock screen.

[0084] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the process, method or device including the element.

[0085] Each embodiment in this specification is described in a progressive manner, and the same and similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. In the description of this specification, the description of the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of this specification. In this specification, the schematic representation of the above terms does not necessarily target the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, in the absence of contradiction, a person skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0086] The above description is only an embodiment of the present specification and is not intended to limit the present specification. For those skilled in the art, the present specification may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present specification shall be included in the scope of the claims of the present specification.

Claims

1. A fingerprint sensor, characterized in that: It includes: a coding mask layer and a photosensitive layer; The coding mask layer includes a plurality of light-transmitting holes and opaque regions located between the light-transmitting holes; the light-transmitting holes on the coding mask layer are arranged according to a preset coding rule, so that the light signals corresponding to the respective light-transmitting holes received by the photosensitive layer are orthogonally incoherent; The photosensitive layer is configured to receive the light signal passing through the light-transmitting holes of the coding mask layer after being reflected by the target object, and convert the received light signal into an electrical signal, so that a processor connected to the fingerprint sensor processes the electrical signal according to the arrangement of the light-transmitting holes and the opaque regions of the coding mask layer to obtain the fingerprint information of the target object; The processor processes the electrical signal according to the arrangement of the light-transmitting holes and the opaque regions of the coding mask layer to obtain the fingerprint information of the target object, including: The processor pre-determines the coding function M corresponding to the coding mask layer of the fingerprint sensor by using the relationship between the sample data and the light intensity distribution function Y of the light signal received on the photosensitive layer and the two-dimensional light intensity distribution function X of the reflected light of the fingerprint on the object plane, and processes the electrical signal based on the coding function M to obtain the fingerprint information of the target object; wherein, the relationship is expressed as: The encoding function M is represented as a one-dimensional array {P O , Q O , P C , Q C }.

2. The fingerprint sensor according to claim 1, characterized in that: The size and / or position of the light-transmitting holes on the coding mask layer are arranged randomly.

3. The fingerprint sensor according to claim 1, characterized in that: The light-transmitting holes of the coding mask layer are arranged in the following manner; Divide the two-dimensional plane defined by the size range of the coding mask layer into m×m coding units, calculate the values of each coding unit by using the following coding model, and set the coding units with a value of 1 as light-transmitting and the coding units with a value of 0 as opaque: Among them, M ij The value of the coding unit in the i-th row and j-th column, where n is any positive integer greater than or equal to 1 and less than or equal to m; Configure the coding rule according to the correspondence between the values of each coding unit and light-transmitting / opaque, and arrange the light-transmitting holes of the coding mask layer by using the configured coding rule.

4. The fingerprint sensor according to claim 3, characterized in that: The coding unit is rectangular.

5. The fingerprint sensor according to claim 4, characterized in that: The side length of the coding unit is any value between 2 and 5 micrometers.

6. The fingerprint sensor according to claim 3, characterized in that: The value of m is a prime number between 500 < m < 5000.

7. The fingerprint sensor according to claim 1, characterized in that: A filter film is further covered on the coding mask layer to allow light of a specified wavelength band to pass through.

8. The fingerprint sensor according to claim 1, characterized in that: The coding mask layer includes a light-transmitting layer and a coding layer; the light-transmitting layer is arranged close to the photosensitive layer, and the coding layer is arranged far from the photosensitive layer; the coding layer includes a plurality of light-transmitting holes and opaque regions located between the light-transmitting holes.

9. A fingerprint recognition device, characterized in that: The fingerprint recognition device includes: An optical cover plate; A display located inside the optical cover plate; The fingerprint sensor according to any one of claims 1 to 8; the fingerprint sensor is arranged on the side of the display away from the optical cover plate; wherein, the coding mask layer of the fingerprint sensor is arranged in the direction close to the display, and the photosensitive layer is arranged in the direction away from the display; A processor, the fingerprint sensor is electrically connected to the processor; the processor is configured to receive the electrical signal sent by the fingerprint sensor, and process the electrical signal based on the arrangement of the light-transmitting holes and the opaque regions of the coding mask layer to obtain fingerprint information; The processor processes the electrical signal based on the arrangement of the light-transmitting holes and the opaque areas of the coding mask layer to obtain the fingerprint information, which is specifically used for: the processor processes the electrical signal according to the arrangement of the light-transmitting holes and the opaque areas of the coding mask layer to obtain the fingerprint information of the target object, including: The processor determines the coding function M corresponding to the coding mask layer of the fingerprint sensor in advance by using the sample data and the relationship between the light intensity distribution function Y of the light signal received on the photosensitive layer and the two-dimensional light intensity distribution function X of the reflected light on the object plane where the fingerprint is located, and processes the electrical signal based on the coding function M to obtain the fingerprint information of the target object; wherein the relationship is expressed as: The encoding function M is represented as a one-dimensional array {P O , Q O , P C , Q C }.

10. A fingerprint recognition method based on the fingerprint recognition device according to claim 9, characterized in that: The method comprises: The photosensitive layer of the fingerprint sensor collects the light signal reflected by the target object placed on the optical cover, converts the light signal into an electrical signal, and transmits it to the processor; The processor receives the electrical signal and obtains the fingerprint information of the target object in the following manner: Performing filtering processing on the electrical signal; Processing the filtered electrical signal based on the arrangement of the light-transmitting holes and the opaque areas of the encoding mask layer of the fingerprint sensor to obtain the fingerprint information of the target object; The method of processing the filtered electrical signal based on the arrangement of the light-transmitting holes and the opaque areas of the coding mask layer of the fingerprint sensor to obtain the fingerprint information of the target object includes: The coding function M corresponding to the coding mask layer of the fingerprint sensor is determined in advance by using the sample data and the relationship between the light intensity distribution function Y of the light signal received on the photosensitive layer and the two-dimensional light intensity distribution function X of the reflected light on the object plane where the fingerprint is located; wherein the relationship is expressed as: The encoding function M is represented as a one-dimensional array {P O , Q O , P C , Q C }; The filtered electrical signal is processed based on the encoding function M to obtain the fingerprint information of the target object.

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