CN110770747B

CN110770747B - Fingerprint identification device and electronic equipment

Info

Publication number: CN110770747B
Application number: CN201980002385.6A
Authority: CN
Inventors: 肖瑜; 程雷刚; 易福建; 凌伟
Original assignee: Shenzhen Goodix Technology Co Ltd
Current assignee: Shenzhen Goodix Technology Co Ltd
Priority date: 2019-05-14
Filing date: 2019-05-14
Publication date: 2023-08-22
Anticipated expiration: 2039-05-14
Also published as: WO2020227940A1; CN110770747A

Abstract

A fingerprint recognition device and an electronic apparatus are provided, which can improve fingerprint recognition performance. The fingerprint identification device comprises: an optical fingerprint sensor comprising: a plurality of pixel unit groups; the plurality of polarization unit groups are arranged above the plurality of pixel unit groups, wherein each polarization unit group corresponds to one pixel unit group; the polarization direction of the polarization units in each polarization unit group is different; the 1/4 wave plate is arranged above the plurality of polarization unit groups; each pixel unit group in the pixel unit groups is used for receiving a group of polarized light signals after the light signals pass through the 1/4 wave plate and a corresponding polarization unit group to obtain a group of electric signals, the light signals comprise fingerprint polarized light signals returned through finger reflection, and the group of electric signals are used for processing to obtain fingerprint electric signals.

Description

Fingerprint identification device and electronic equipment

Technical Field

The present application relates to the field of fingerprint recognition technology, and more particularly, to a fingerprint recognition device and an electronic apparatus.

Background

With the advent of the full-screen mobile phone era, applications of fingerprint recognition devices arranged under or in a screen in terminal equipment such as mobile phones have also been widely developed. In the fingerprint identification process, the fingerprint identification device receives a large amount of screen natural light signals except for fingerprint light signals with fingerprint information reflected by fingers, and the light intensity of the screen natural light signals is far greater than that of the fingerprint light signals, so that the fingerprint light signals in the light signals received by the fingerprint identification device are weak, meanwhile, the screen structure carried by the screen natural light signals and the Indium Tin Oxide (ITO) pattern information further influence the performance of fingerprint identification, and bad experience is brought to users.

Disclosure of Invention

The embodiment of the application provides a fingerprint identification device and electronic equipment, which can improve fingerprint identification performance.

In a first aspect, a fingerprint recognition device is provided, comprising:

an optical fingerprint sensor comprising: a plurality of pixel unit groups;

the plurality of polarization unit groups are arranged above the plurality of pixel unit groups, wherein each polarization unit group corresponds to one pixel unit group; the polarization direction of the polarization units in each polarization unit group is different;

the 1/4 wave plate is arranged above the plurality of polarization unit groups;

each pixel unit group in the pixel unit groups is used for receiving a group of polarized light signals after the light signals pass through the 1/4 wave plate and a corresponding polarization unit group to obtain a group of electric signals, the light signals comprise fingerprint polarized light signals returned through finger reflection, and the group of electric signals are used for processing to obtain fingerprint electric signals.

In the fingerprint identification scheme provided by the application, the 1/4 wave plate and the plurality of polarization unit groups are arranged above the plurality of pixel unit groups, and the polarization directions of the polarization units in each polarization unit group are different, so that the fingerprint optical signals received by the pixel units corresponding to different polarization units are different from the converted electric signals, and the fingerprint electric signals corresponding to the fingerprint polarized light are obtained by processing the electric signals of different pixel units, thereby improving the fingerprint identification performance of the fingerprint identification device.

In one possible implementation, the fingerprint polarized light signal passes through the 1/4 wave plate and then is linearly polarized light.

In one possible implementation, the plurality of polarization cell groups are identical.

In one possible implementation, the plurality of polarization unit groups includes a first polarization unit group and a second polarization unit group, the first polarization unit group being different from the second polarization unit group.

In one possible implementation, the polarization direction of the polarization units in the first polarization unit group is different from the polarization direction of the polarization units in the second polarization unit group.

In one possible implementation manner, the arrangement manner of the polarized units in the first polarized unit group is different from the arrangement manner of the polarized units in the second polarized unit group.

In one possible implementation manner, any one of the plurality of polarization unit groups includes at least two polarization units, and any one of the plurality of pixel unit groups includes at least two pixel units, where one polarization unit corresponds to at least one pixel unit.

In one possible implementation, at least one of the plurality of polarization unit groups includes a first polarization unit and a second polarization unit, and a difference between polarization directions of the first polarization unit and the second polarization unit is 90 °.

In a possible implementation, the set of electrical signals is used to subtract any two different electrical signals from the fingerprint electrical signal.

In a possible implementation, the set of electrical signals is used to perform convolution calculations to obtain the fingerprint electrical signal.

In one possible implementation, at least one of the plurality of polarization unit groups includes a first polarization unit, a second polarization unit, a third polarization unit, and a fourth polarization unit;

the difference between the polarization directions of the first polarization unit and the second polarization unit is 90 degrees, and the difference between the polarization directions of the third polarization unit and the fourth polarization unit is 90 degrees.

In a possible implementation manner, the set of electrical signals includes a first electrical signal, a second electrical signal, a third electrical signal, and a fourth electrical signal, and is used for calculating the fingerprint electrical signal according to a formula, where the formula is:

wherein S is the fingerprint electrical signal, a is the first electrical signal, corresponding to the first polarization unit, B is the second electrical signal, corresponding to the second polarization unit, C is the third electrical signal, corresponding to the third polarization unit, D is the fourth electrical signal, corresponding to the fourth polarization unit.

In one possible implementation manner, the fingerprint identification device further includes:

the first optical component is arranged above the optical fingerprint sensor;

the first optical assembly includes: at least one light blocking layer and a microlens array;

the at least one light blocking layer is positioned below the micro lens array and is provided with a plurality of light passing small holes;

the optical fingerprint sensor is used for receiving optical signals converged to the plurality of light-passing holes through the micro lens array and passing through the plurality of light-passing holes.

In one possible implementation, the first optical component further includes:

the first filter layer is arranged above the first optical component or in an optical path between the first optical component and the optical fingerprint sensor and is used for filtering out optical signals of non-target wave bands and transmitting the optical signals of the target wave bands.

In one possible implementation, the first filter layer is disposed over the plurality of polarization unit groups, and the first optical component is disposed over the first filter layer.

the second optical component is arranged above the optical fingerprint sensor;

The second optical assembly includes: at least one optical lens.

In one possible implementation, the second optical assembly further includes:

and a first fixing device for fixing the at least one optical lens above the optical fingerprint sensor.

In one possible implementation, the second optical assembly further includes:

and the second filter layer is arranged above the at least one optical lens or in an optical path between the at least one optical lens and the optical fingerprint sensor and is used for filtering out optical signals of non-target wave bands and transmitting the optical signals of the target wave bands.

In one possible implementation, the plurality of polarization unit groups are integrated in the optical fingerprint sensor.

In one possible implementation manner, the fingerprint identification device further includes: a processing unit;

the processing unit is used for processing the group of electrical signals to obtain the fingerprint electrical signals.

In one possible implementation manner, the fingerprint identification device further includes: an amplifying unit and an analog-to-digital conversion unit;

the amplifying unit is used for receiving and amplifying the fingerprint electric signal to obtain an amplified fingerprint electric signal, and the analog-to-digital conversion unit is used for receiving the amplified fingerprint electric signal and converting the amplified fingerprint electric signal into a digital fingerprint electric signal.

In a second aspect, an electronic device is provided, comprising a fingerprint recognition device as in the first aspect or any possible implementation of the first aspect.

In one possible implementation, the electronic device further includes a display screen including a circular polarizer therein;

the fingerprint identification device is arranged below the display screen.

Drawings

Fig. 1 is a schematic structural diagram of an electronic device to which an embodiment of the present application is applied.

Fig. 2 is a schematic structural view of a fingerprint recognition device according to an embodiment of the present application.

Fig. 3 is a schematic diagram of light intensity of an optical signal received by the optical fingerprint sensor according to an embodiment of the present application.

Fig. 4 is a schematic structural view of another fingerprint recognition device according to an embodiment of the present application.

Fig. 5 is a schematic diagram of a fingerprint electric signal of an optical fingerprint sensor according to an embodiment of the present application.

Fig. 6 is a schematic structural view of another fingerprint recognition device according to an embodiment of the present application.

Fig. 7 is a schematic block diagram of another fingerprint recognition device according to an embodiment of the present application.

Fig. 8 is a schematic structural view of another fingerprint recognition device according to an embodiment of the present application.

Fig. 9a is a schematic diagram of one design of a plurality of polarization cell groups.

Fig. 9b is a schematic diagram of another design of a plurality of polarization cell groups.

Fig. 9c is a schematic diagram of another design of a plurality of polarization cell groups.

Fig. 9d is a schematic diagram of another design of a plurality of polarization cell groups.

Fig. 10a is a schematic diagram of another design of a plurality of polarization cell groups.

Fig. 10b is a schematic diagram of the received light intensity of a plurality of pixel cell groups corresponding to fig. 10 a.

Fig. 10c is a schematic diagram of a convolution template of a convolution calculation method according to an embodiment of the present disclosure.

Fig. 11a is a schematic diagram of another design of a plurality of polarization cell groups.

Fig. 11b is a schematic diagram of another design of a plurality of polarization cell groups.

Fig. 11c is a schematic diagram of another design of a plurality of polarization cell groups.

Fig. 12a is a schematic diagram of another design of a plurality of polarization cell groups.

Fig. 12b is a schematic diagram of electrical signals of a plurality of pixel cell groups corresponding to fig. 11 a.

Fig. 13 is a schematic block diagram of an electronic device in accordance with an embodiment of the application.

Detailed Description

The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings.

It should be understood that the embodiments of the present application may be applied to optical fingerprint systems, including but not limited to optical fingerprint identification systems and products based on optical fingerprint imaging, and the embodiments of the present application are only described by way of example in terms of optical fingerprint systems, but should not be construed as limiting the embodiments of the present application in any way, and the embodiments of the present application are equally applicable to other systems employing optical imaging techniques, etc.

As a common application scenario, the optical fingerprint system provided by the embodiment of the application can be applied to smart phones, tablet computers and other mobile terminals or other terminal devices with display screens; more specifically, in the above terminal device, the fingerprint recognition device may be specifically an optical fingerprint device, which may be disposed in a partial area or an entire area Under the display screen, thereby forming an Under-screen (Under-display) optical fingerprint system. Alternatively, the fingerprint recognition device may be partially or fully integrated inside the display screen of the terminal device, thereby forming an In-screen (In-display) optical fingerprint system.

In the embodiments shown below, the same reference numerals are used for the same structures for the sake of understanding, and detailed description of the same structures is omitted for the sake of brevity.

As shown in fig. 1, which is a schematic structural diagram of a terminal device to which an embodiment of the present application may be applied, the terminal device 1 includes a display screen 120 and an optical fingerprint device 130, where the optical fingerprint device 130 is disposed in a local area below the display screen 120. The optical fingerprint device 130 includes an optical fingerprint sensor, the optical fingerprint sensor includes a sensing array 133 having a plurality of optical sensing units 131, and an area where the sensing array 133 is located or a sensing area thereof is the fingerprint detection area 103 of the optical fingerprint device 130. As shown in fig. 1, the fingerprint detection area 103 is located in the display area of the display screen 120. In an alternative embodiment, the optical fingerprint device 130 may be further disposed at other locations, such as a side surface of the display screen 120 or an edge non-light-transmitting area of the terminal device 1, and the optical signal of at least part of the display area of the display screen 120 is guided to the optical fingerprint device 130 by an optical path design, so that the fingerprint detection area 103 is actually located in the display area of the display screen 120.

It should be appreciated that the area of the fingerprint detection area 103 may be different from the area of the sensing array of the optical fingerprint device 130, for example, by a light path design such as lens imaging, a reflective folded light path design, or other light path designs such as light converging or reflecting, the area of the fingerprint detection area 103 of the optical fingerprint device 130 may be made larger than the area of the sensing array of the optical fingerprint device 130. In other alternative implementations, the fingerprint detection area 103 of the optical fingerprint device 130 may be designed to substantially coincide with the area of the sensing array of the optical fingerprint device 130 if light path guiding is performed, for example, by light collimation.

Therefore, when the user needs to unlock the terminal device or perform other fingerprint verification, the user only needs to press the finger against the fingerprint detection area 103 located on the display screen 120, so as to implement fingerprint input. Since fingerprint detection can be implemented in the screen, the terminal device 1 adopting the above structure does not need to have a special reserved space on the front surface to set fingerprint keys (such as Home keys), so that a comprehensive screen scheme can be adopted, that is, the display area of the display screen 120 can be basically expanded to the front surface of the whole terminal device 1.

It should be understood that, in a specific implementation, as shown in fig. 1, the terminal device 1 further includes a transparent protective cover plate 110, where the cover plate 110 may be a glass cover plate or a sapphire cover plate, and is located above the display screen 120 and covers the front surface of the terminal device 1. Because, in the embodiment of the present application, the so-called finger pressing on the display screen 120 actually means pressing on the cover plate above the display screen 120 or the surface of the protective layer covering the cover plate.

As an alternative embodiment, the display 120 may be a display having a self-luminous display unit, such as an Organic Light-Emitting Diode (OLED) display or a Micro-LED (Micro-LED) display. Taking an OLED display as an example, the optical fingerprint device 130 may use a display unit (i.e., an OLED light source) of the OLED display 120 located in the fingerprint detection area 103 as an excitation light source for optical fingerprint detection. When the finger 140 is pressed against the fingerprint detection area 103, the display 120 emits a light 111 to the target finger 140 above the fingerprint detection area 103, the light 111 is reflected on the upper surface of the cover 110 to form reflected light, wherein a gap is formed between the finger ridge (ridge) and the cover 110, and a gap is formed between the finger valley (valley) and the cover 110, so that the reflectivity of the light 111 at the contact area between the finger ridge and the cover is 0, the reflectivity of the light 111 at the contact area between the finger valley and the cover is about 4%, and therefore, the light intensity of the reflected light 151 formed by the reflection of the light 111 at the contact area between the finger ridge and the cover is smaller than the reflected light 152 formed by the reflection of the light 111 at the contact area between the finger valley and the cover. After passing through the optical component 132, the reflected light is received by the sensing array 134 in the optical fingerprint device 130 and converted into a corresponding electrical signal, i.e. a fingerprint detection signal; fingerprint image data can be obtained based on the fingerprint detection signal, and fingerprint matching verification can be further performed, thereby realizing an optical fingerprint recognition function at the terminal device 1.

In other embodiments, the optical fingerprint device 130 may also employ an internal light source or an external light source to provide the optical signal for fingerprint detection. In this case, the optical fingerprint device 130 may be adapted to a non-self-luminous display screen, such as a liquid crystal display screen or other passive light emitting display screen. Taking the application to a liquid crystal display screen with a backlight module and a liquid crystal panel as an example, in order to support the under-screen fingerprint detection of the liquid crystal display screen, the optical fingerprint system of the terminal device 1 may further include an excitation light source for optical fingerprint detection, where the excitation light source may be specifically an infrared light source or a light source of non-visible light with a specific wavelength, which may be disposed below the backlight module of the liquid crystal display screen or disposed in an edge area below a protective cover plate of the terminal device 1, and the optical fingerprint device 130 may be disposed below the edge area of the liquid crystal panel or the protective cover plate and guided by an optical path so that fingerprint detection light may reach the optical fingerprint device 130; alternatively, the optical fingerprint device 130 may be disposed below the backlight module, and the backlight module may be configured to allow fingerprint detection light to pass through the liquid crystal panel and the backlight module and reach the optical fingerprint device 130 by making holes or other optical designs on a film layer such as a diffusion sheet, a brightness enhancing sheet, a reflective sheet, etc. When the optical fingerprint device 130 is used to provide an optical signal for fingerprint detection using an internal light source or an external light source, the detection principle is consistent with that described above.

It will be appreciated that the terminal device 1 may also comprise a circuit board 150 arranged below said optical fingerprint means 130. The optical fingerprint device 130 may be adhered to the circuit board 150 by a back adhesive, and electrically connected to the circuit board 150 by bonding pads and wire bonding. The optical fingerprint apparatus 130 may enable electrical interconnection and signal transmission with other peripheral circuits or other elements of the terminal device 1 through the circuit board 150. For example, the optical fingerprint device 130 may receive a control signal of the processing unit of the terminal apparatus 1 through the circuit board 150, and may also output a fingerprint detection signal from the optical fingerprint device 130 to the processing unit or the control unit of the terminal apparatus 1 or the like through the circuit board 150.

On the other hand, in some embodiments, the optical fingerprint device 130 may include only one optical fingerprint sensor, where the area of the fingerprint detection area 103 of the optical fingerprint device 130 is small and the position is fixed, so that the user needs to press the finger to a specific position of the fingerprint detection area 103 when inputting the fingerprint, otherwise, the optical fingerprint device 130 may not be able to acquire the fingerprint image, which may cause poor user experience. In other alternative embodiments, the optical fingerprint device 130 may specifically include a plurality of optical fingerprint sensors; the plurality of optical fingerprint sensors may be disposed side by side below the display screen 120 in a spliced manner, and sensing areas of the plurality of optical fingerprint sensors together form the fingerprint detection area 103 of the optical fingerprint device 130. That is, the fingerprint detection area 103 of the optical fingerprint device 130 may include a plurality of sub-areas, each corresponding to a sensing area of one of the optical fingerprint sensors, so that the fingerprint acquisition area 103 of the optical fingerprint device 130 may be extended to a main area of the lower half of the display screen, that is, to a finger usual press area, so as to implement a blind press type fingerprint input operation. Alternatively, when the number of optical fingerprint sensors is sufficient, the fingerprint detection area 103 may also be extended to half or even the whole display area, thereby achieving half-screen or full-screen fingerprint detection.

It should also be understood that in embodiments of the present application, the sensing array in the optical fingerprint device may also be referred to as a pixel array, and the optical sensing unit or sensing units in the sensing array may also be referred to as pixel units.

It should be noted that, the optical fingerprint device in the embodiment of the present application may also be referred to as an optical fingerprint recognition module, a fingerprint recognition device, a fingerprint recognition module, a fingerprint acquisition device, etc., where the above terms may be replaced with each other.

Fig. 2 is a schematic structural diagram of a fingerprint recognition device 10 according to an embodiment of the present application, as shown in fig. 2, the fingerprint recognition device 10 is disposed below a display screen 120, and the fingerprint recognition device 10 is configured to receive an optical signal reflected by a finger, convert the optical signal into an electrical signal, and perform fingerprint recognition. The display 120 is an OLED display, and includes a cover plate 121, a circular polarizer 122, a display assembly 124, a glass substrate 126, and a light shielding layer 127.

The display assembly 124 includes an organic light emitting layer 125, where the organic light emitting layer 125 is used to implement a display function in cooperation with a display driving circuit, for example, the organic light emitting layer 125 may be an OLED organic light emitting panel made by using low temperature polysilicon (low temperature poly-silicon, LTPS) technology, and has a plurality of light emitting pixel units grown on the glass substrate 126. The circular polarizer 122 may include a linear polarizer and a 1/4 wave plate, where the linear polarizer is disposed above the 1/4 wave plate, and is used to suppress reflection of the display screen 120 on ambient light, so as to achieve higher display contrast. The cover plate 121 may be disposed on the circular polarizer 122 through a glue layer for protecting the display screen 120. The fingerprint recognition device 10 is placed or attached to the bottom of the glass substrate 126, whereby off-screen optical fingerprint recognition can be achieved locally or fully in the display area of the display screen. The light shielding layer 127 is disposed below the glass substrate, and has a window 128 thereon for passing a fingerprint light signal formed by reflection from a finger of a human body, and the fingerprint light signal is used for fingerprint identification.

Specifically, as shown in fig. 2, the display layer 125 emits the first natural light signal 101 to the finger 140, where the first natural light signal 101 passes through the circular polarizer 122, and after being reflected by the finger 140, the light intensity is reduced, so as to form a first fingerprint light signal. After passing through the circular polarizer 122 and the window 127, the light intensity of the first fingerprint light signal further decreases, forming a second fingerprint light signal 1011, and the second fingerprint light signal 1011 is received by the fingerprint recognition device 10.

Meanwhile, the second natural light signal 102 emitted by the display component 125 may also be directly received by the fingerprint recognition device 10 through the window 127. The second natural light signal 102 is not attenuated by the processed light intensity of the circular polarizer 122 in the display screen, so that the light intensity of the second natural light signal 102 is much greater than the light intensity of the second fingerprint light signal 1011 and tends to be constant. In addition, the stray light 103 is a light signal reflected by each laminated structure in the display screen 120, and the light intensity is not attenuated by the processing of the circular polarizer 122, so that the stray light 103 also has a larger light intensity. Therefore, as shown in fig. 3, when the fingerprint identification device 10 receives the stray light 103, the second natural light signal 102 and the second fingerprint light signal 1011 simultaneously, the second fingerprint light signal 1011 for fingerprint identification has a small ratio in the total received light signal, and the light intensity variation of the fingerprint ridge and the fingerprint valley in the total light signal is weak, so that it is difficult to identify the fingerprint signal, and the fingerprint identification performance of the fingerprint identification device 10 is greatly limited.

In addition, the second natural light signal 102 further carries information of the light emitting pixel unit, the stray light 103 further carries information of each lamination structure in the display screen 120 and information of the touch ITO pattern of the display screen, when the fingerprint identification device 10 receives the second natural light signal 102, the stray light 103 and the second fingerprint light signal 1011 at the same time, interference information carried by the second natural light signal 102 and the stray light 103 easily interferes with imaging of the second fingerprint light signal 1011 by the fingerprint identification device 10, thereby affecting quality of fingerprint images and limiting fingerprint identification performance of the fingerprint identification device 10.

Based on the above, the application provides a fingerprint identification scheme, wherein different polarization units are arranged above different pixel units in the fingerprint identification device, so that the received light intensities of the different pixel units are different, and the converted electric signals are different.

Hereinafter, referring to fig. 4 to 11, a fingerprint recognition device according to an embodiment of the present application will be described in detail.

It should be understood that the numbers and arrangements of the pixel units, the polarization units, and the polarization unit groups, etc. in the embodiments of the present application shown below are only exemplary, and should not be construed as limiting the present application in any way.

Fig. 4 is a schematic structural diagram of a fingerprint recognition device 20 according to an embodiment of the present application, where the fingerprint recognition device 20 includes:

an optical fingerprint sensor 200 comprising: a plurality of pixel unit groups; such as the first pixel cell group 210 of fig. 4;

the plurality of polarization unit groups are arranged above the plurality of pixel unit groups, wherein each polarization unit group corresponds to one pixel unit group; each polarization unit group at least comprises 2 polarization units, and the polarization directions of the polarization units in each polarization unit group are different; for example, the first polarization unit group 310 in fig. 4 corresponds to the first pixel unit group 210 and is disposed above the first pixel unit group 210, where the first polarization unit group 310 includes a first polarization unit 311 and a second polarization unit 312, and polarization directions of the first polarization unit and the second polarization unit are different.

The 1/4 wave plate 500 is disposed above the plurality of polarization unit groups.

Each pixel unit group in the plurality of pixel unit groups is used for receiving a set of polarized light signals after the light signals pass through the 1/4 wave plate 500 and a corresponding one of the polarized unit groups to obtain a set of electric signals, the light signals comprise fingerprint polarized light signals returned by finger reflection, the set of electric signals are used for processing to obtain fingerprint electric signals, and the fingerprint electric signals are electric signals corresponding to the fingerprint polarized light signals.

For example, in fig. 4, the first polarization unit 311 processes the optical signal to obtain a first polarized optical signal, the first pixel unit 211 is used for converting the first polarized optical signal into a first electrical signal, the second polarization unit 312 processes the optical signal to obtain a second polarized optical signal, the second pixel unit 212 is used for converting the second polarized optical signal into a second electrical signal, and a group of electrical signals consisting of the first electrical signal and the second electrical signal is used for processing to obtain a fingerprint electrical signal.

Specifically, in the embodiment of the present application, the optical fingerprint sensor includes a pixel array formed by a plurality of pixel unit groups, and a reading circuit and other auxiliary circuits electrically connected to the pixel array, which may be fabricated on a chip (Die) through a semiconductor process. The pixel units in the pixel unit groups are used for receiving the optical signals passing through the polarization units and processing the received optical signals to obtain electric signals, and the pixel unit groups receive a group of polarized optical signals and convert the polarized optical signals into a group of electric signals. Alternatively, the plurality of pixel units may employ a photodiode (photo diode), a metal oxide semiconductor field effect transistor (metal oxide semiconductor field effect transistor, MOSFET), or the like. Optionally, the plurality of pixel units have higher light sensitivity and higher quantum efficiency for light of a specific wavelength, so as to detect light signals of the corresponding wavelength.

It should be understood that the first pixel unit 211 and the second pixel unit 212 in fig. 4 may also be the optical sensing unit 131 in fig. 1, and the related functional and structural descriptions thereof may be referred to in the foregoing description.

Specifically, in the embodiment of the present application, the 1/4 wave plate 500 may be an optical device capable of generating an additional optical path difference (i.e., a phase difference Δj) between two optical vibrations perpendicular to each other. Wherein Δj=2kpi (k is an integer) is synthesized as linearly polarized light; Δj= (2k+1) pi/2, and θ=45°, is synthesized as circularly polarized light. The 1/4 wave plate 500 may also be referred to as a quarter wave plate (quarter-wave plate). The 1/4 wave plate 500 may be a birefringent wafer with a precise thickness. Birefringent wafers such as quartz, calcite or mica have their optical axes parallel to the wafer surface.

The incident light received by the 1/4 wave plate 500 is decomposed into ordinary light (o light) and extraordinary light (e light), the refractive index of the crystal is different for the two lights, and the 1/4 wave plate 500 can generate additional 1/4 optical path difference between the two lights (o light and e light) perpendicular to each other. For example, assuming that linearly polarized light is incident on the 1/4 wave plate 500 and θ=45°, light passing out of the 1/4 wave plate is circularly polarized light; conversely, the circularly polarized light is changed into linearly polarized light after passing through the 1/4 wave plate 500. When the linearly polarized light vertically enters the 1/4 wave plate, and the polarized light and the optical axis surface (vertical natural splitting surface) of the mica form an angle theta, the polarized light is emergent to form elliptical polarized light. Particularly when θ=45°, the outgoing light is circularly polarized light.

Specifically, in the embodiment of the present application, the plurality of polarization unit groups may form the polarization assembly 300, and the polarization units in each polarization unit group, for example, the first polarization unit 311 and the second polarization unit 312 in fig. 4 may implement selection of a polarization state with a high extinction ratio, may convert natural light or circularly polarized light into linearly polarized light, allow an optical signal having a vibration direction parallel to the polarization direction to pass therethrough, and absorb an optical signal having a vibration direction perpendicular to the polarization direction. Specifically, the first and second polarization units 311 and 312 may be Polarizers (PL) or polarizing films.

Optionally, the plurality of polarization unit groups may be disposed above the plurality of pixel unit groups by a second fixing device, where the second fixing device is disposed in a non-photosensitive area of the optical fingerprint sensor, and is configured to connect the plurality of polarization unit groups and the plurality of pixel unit groups.

Alternatively, the plurality of polarization unit groups may be integrated in the optical fingerprint sensor together with the plurality of pixel unit groups, and in particular, the plurality of polarization unit groups may be formed by performing a plating process on the plurality of pixel unit groups of the optical fingerprint sensor, for example, a polarization film may be prepared above the plurality of pixel units of the optical fingerprint sensor by an atomic layer deposition, a sputtering plating, an electron beam evaporation plating, an ion beam plating, or the like. Specifically, a plurality of metal wire grid micro polarizers can be prepared on a plurality of pixel unit groups by adopting a complementary metal oxide semiconductor (Complementary Metal Oxide Semiconductor, CMOS) process as a polarization unit group, and the metal wire grid micro polarizers are in a periodic metal wire grid array, wherein the width and the interval of the metal wire grids are tens to hundreds of nanometers.

Specifically, the light signals received by each of the plurality of polarization unit groups include natural light signals, stray light and fingerprint polarized light signals returned by finger reflection, wherein the natural light signals can include light signals such as screen light or ambient light emitted by a display screen, the stray light is light signals generated by reflection of each film structure in the display screen, and meanwhile, the stray light does not pass through a circular polarizer in the display screen and is natural light signals.

In the embodiment of the present application, the fingerprint polarized light signal is linearly polarized light after passing through the 1/4 wave plate 500. For example, as shown in fig. 4, the natural light signal 201 and the fingerprint polarized light signal 202 are incident into the first polarization unit group 310, that is, the first polarization unit 311 and the second polarization unit 312, and the fingerprint polarized light signal 202 is circularly polarized light, and is changed into linearly polarized light after passing through the 1/4 wave plate 500. The natural light signal 201 is changed into a first natural polarized light signal and a second natural polarized light signal by the first polarization unit 311 and the second polarization unit 312, and the light intensities of the first natural polarized light signal and the second natural polarized light signal are the same, and are not greater than 1/2 of the light intensity of the natural light signal 201.

The optical signals of the fingerprint polarized optical signal 202 after passing through the first polarization unit 311 and the second polarization unit 312 are changed into a first fingerprint polarized optical signal and a second fingerprint polarized optical signal, the light intensities of the first fingerprint polarized optical signal and the second fingerprint polarized optical signal are different, and if the included angle between the vibration direction of the fingerprint polarized optical signal 202 and the polarization direction of the first polarization unit 311 is smaller than the included angle between the vibration direction of the fingerprint polarized optical signal 202 and the polarization direction of the second polarization unit 312, the light intensity of the first fingerprint polarized optical signal is larger than the light intensity of the second fingerprint polarized optical signal. In particular, if the vibration direction of the fingerprint polarized light signal 202 is perpendicular to the polarization direction of the first polarization unit 311 or the second polarization unit 312, the light intensity of the first fingerprint polarized light signal or the second fingerprint polarized light signal is 0.

Specifically, in the present embodiment, the first polarized light signal received by the first pixel unit 211 includes the first natural polarized light signal and the first fingerprint polarized light signal, and the light intensity of the first polarized light signal is converted into the first electrical signal; the second polarized light signal received by the second pixel unit 212 includes the second natural polarized light signal and the second fingerprint polarized light signal, and converts the light intensity of the second polarized light signal into a second electrical signal, where the light intensities of the first fingerprint polarized light signal and the second fingerprint polarized light signal are different, and the light intensities of the first natural polarized light signal and the second natural polarized light signal are the same, so that the processed first electrical signal and the processed second electrical signal are different. The fingerprint electrical signal is processed based on the first and second electrical signals.

Alternatively, in the embodiment of the present application, the fingerprint recognition device 20 may be a fingerprint module, or the fingerprint recognition device 20 may be an electronic device including a fingerprint module, which is not limited in the embodiment of the present application.

It should be understood that, in the embodiment of the present application, the natural light signal 201 may further include other light signals without polarization, such as stray light reflected by each laminated structure in the display screen, and the stray light does not pass through the circular polarizer in the display screen, that is, the stray light may be natural light. As in the case of natural light signals passing through the polarization units, the light intensity changes consistently after the stray light passes through different polarization units, and the light intensity of the stray light is not greater than 1/2 of the light intensity of the original stray light. For convenience of description, the natural light signal 201 and the stray light may also be collectively referred to as the natural light signal 201.

In the embodiment of the application, when fingerprint identification is performed, after the fingerprint polarized light signals pass through the polarized units with different polarization directions, the light intensities of the obtained light signals are different, so that the electric signals processed by the pixel units corresponding to the different polarized units are different, further, the different electric signals are processed, the influence of the same natural light, stray light and other interference light is removed, the fingerprint detection electric signals corresponding to the fingerprint polarized light signals are determined, and the fingerprint identification performance of the fingerprint identification device is improved.

For example, as shown in fig. 5, when the fingerprint recognition device 20 receives the natural light signal 201 and the fingerprint polarized light signal 202 at the same time, the processed fingerprint electric signal only includes the electric signal corresponding to the fingerprint polarized light, so that the electric signal corresponding to the fingerprint ridge and the fingerprint valley has a large variation, which is convenient for the fingerprint recognition device 20 to perform fingerprint recognition.

Optionally, the fingerprint recognition device 20 further includes: the first optical component 400 is disposed above the optical fingerprint sensor 200, and the first optical component 400 is disposed above the optical fingerprint sensor 200. The first optical component 400 may specifically include a Filter layer (Filter), a light guiding layer or a light path guiding structure, and other optical elements, where the Filter layer may be used to Filter out ambient light that penetrates the finger, and the light guiding layer or the light path guiding structure is mainly used to guide reflected light reflected from the finger surface to the sensing array for optical detection.

In a specific implementation, the first optical component 400 may be encapsulated in the optical fingerprint sensor 200, or the first optical component 400 may be disposed outside the optical fingerprint sensor 200, for example, the first optical component 400 is attached to the optical fingerprint sensor 200, or a part of elements of the first optical component 400 are integrated in the optical fingerprint sensor 200. It will be appreciated that when the polarizing component is disposed above the optical fingerprint sensor 200, the first optical component 400 is actually disposed on the polarizing component 300; the first optical assembly 400 is packaged in the optical sensor 200, in effect together with the polarizing assembly 300, in the optical sensor 200.

In one possible embodiment, the first optical assembly 400 is disposed above the polarizing assembly 300, as shown in fig. 6, and the first optical assembly 400 includes: at least one light blocking layer 410 and a microlens array 420;

the at least one light blocking layer 410 is provided with a plurality of light-passing holes;

the microlens array 420 is disposed above the at least one light blocking layer 410, and is configured to collect the optical signals to a plurality of light passing holes of the at least one light blocking layer 410, and the optical signals are transmitted to the polarization component 300 through the plurality of light passing holes of the at least one light blocking layer 410.

The at least one light blocking layer 410 may be formed over the polarizing element 300 by a semiconductor process growth or other processes, for example, by atomic layer deposition, sputtering, e-beam evaporation, ion beam plating, etc. to form a thin film of non-transparent material over the polarizing element 300, followed by aperture pattern lithography and etching to form a plurality of light passing apertures. The at least one light blocking layer 410 can block optical interference between adjacent microlenses, and enable optical signals corresponding to the pixel units to be converged into the light passing apertures through the microlenses and transmitted to the polarization units and the pixel units via the light passing apertures for optical fingerprint imaging. Optionally, the polarization component 300 is isolated from the at least one light blocking layer 410 and the multiple light blocking layers 410 by transparent dielectric layers.

The microlens array 420 is formed of a plurality of microlenses, which may be formed over the at least one light blocking layer 410 by a semiconductor growth process or other process, and each microlens may correspond to one of the pixel units of the optical fingerprint sensor 200, respectively.

It should be appreciated that the first optical assembly 400 may be disposed anywhere in the optical path between the display 120 and the optical fingerprint sensor 200, for example: disposed between the optical fingerprint sensor 200 and the polarization assembly 300, or disposed between the polarization assembly 300 and the 1/4 wave plate 500, or disposed between the 1/4 wave plate 500 and the display screen 120.

By adopting the fingerprint identification device provided by the embodiment of the application, the thickness of the fingerprint identification device is reduced while the interference of optical signals such as natural light in the optical signals is reduced, so that the performance of the optical fingerprint identification device is further improved.

Optionally, as shown in fig. 6, the first optical assembly 400 further includes: the first filtering layer 430 is configured to filter out optical signals of non-target wavelength bands, and transmit optical signals of target wavelength bands (i.e., optical signals of a wavelength band required for fingerprint image acquisition).

Optionally, the first filter layer 430 is disposed above the first optical component or in the optical path between the first optical component and the optical fingerprint sensor. Specifically, the first filter layer 430 is disposed above the microlens array 420 or in the optical path between the microlens array 420 and the polarization assembly 300. For example, as shown in fig. 6, the filter layer is disposed above the plurality of polarization unit groups.

Optionally, the first filter layer 430 is disposed above the microlens array 420, for example, a buffer layer is disposed above the microlens array 420, and the buffer layer is a transparent medium buffer layer with an optical refractive index lower than that of the microlens array 420, and optionally, the buffer layer has an optical refractive index lower than 1.3. The lower surface of the first filter layer 430 is completely attached to the upper surface of the buffer layer by an adhesive layer. Alternatively, the adhesive layer may be a low refractive index glue having a refractive index of less than 1.25.

Optionally, the first filter layer 430 may be further fixed above the microlens array 420 by a third fixing device, for example, a frame glue or other supporting member is disposed on a non-photosensitive area around the microlens array 420 to support and fix the first filter layer 430 above the microlens array 420, and an air gap layer exists between a lower surface of the first filter layer 430 and an upper surface of the microlens array 420.

Optionally, the first filter layer 430 may also be disposed in the optical path between the microlens array 420 and the optical fingerprint sensor 200 by a third fixing device such as a frame glue. In particular, the first filter layer 430 may be disposed between the light blocking layer 410 and the polarization component 300.

Optionally, the first filter layer 430 may also be integrated with the polarizing component 300 in an optical fingerprint sensor, and in particular, the filter layer 430 may be formed by coating light above the polarizing component 300 by an evaporation process.

Optionally, the first filter layer 430 is a light wavelength cut-off filter, and is configured to filter out light signals of a specific wavelength band, so as to reduce the influence of ambient light signals of the specific wavelength band, thereby improving fingerprint recognition performance.

In one possible embodiment, as shown in FIG. 7, the 1/4 wave plate 500 is disposed above the first optical assembly 400. The screen light signal 301 emitted by the light emitting layer 125 in the display screen 120 is a natural light signal, and is received by the first polarization unit group 310 after passing through the 1/4 wave plate 500 and the optical assembly 400.

The screen light signal passes through the circular polarizer 122 in the display screen 120 to form screen linear polarized light, the screen linear polarized light is reflected by the finger 140 and then passes through the circular polarizer 122 again to form circular polarized light 302, the circular polarized light 302 passes through the 1/4 wave plate 500 to form linear polarized light 304, the linear polarized light 304 is the fingerprint polarized light signal, and the linear polarized light 304 is received by the first polarization unit group 310 after passing through the optical component 400.

Alternatively, in an embodiment of the present application, the natural light signal 301 may be the natural light signal 201 in fig. 4, and the linearly polarized light 304 may be the fingerprint polarized light signal 202 in fig. 4. In the embodiment of the present application, the processing procedures of the first polarization unit 311 and the second polarization unit 312 on the natural light signal 301 and the linearly polarized light 304 may refer to the corresponding procedures in the foregoing method embodiment, and will not be described herein. In another possible embodiment, as shown in fig. 8, the fingerprint recognition device 20 further includes: a second optical assembly 600, the second optical assembly 600 comprising a lens assembly 610 having a lens group of at least one spherical or aspherical optical lens for converging reflected light reflected from a finger to a plurality of pixel units of an optical fingerprint sensor therebelow, such that the plurality of pixel units can image based on the reflected light, thereby obtaining a fingerprint image of the finger. Optionally, the optical lens layer may further form a pinhole in the optical path of the lens unit, and the pinhole may cooperate with the optical lens layer to expand the field of view of the fingerprint recognition device to improve the fingerprint imaging effect of the fingerprint recognition device 20.

Alternatively, as shown in fig. 8, the lens assembly 610 may be disposed below the display screen 120 and above the optical fingerprint sensor 200 by a first fixture 620.

Alternatively, the first fixing device 620 may be a bracket or a tube, in which one or more optical lenses of the lens assembly 610 are fixed, and the tube or the bracket is used to fix the lens assembly 610 above the optical fingerprint sensor 200, and the optical signal passes through the lens assembly 610 and then enters the optical fingerprint sensor 200. Alternatively, when the first fixing device 620 is a lens barrel, the first fixing device 620 may further include a lens base, the lens barrel and the lens base may be two separate components and may be fixed together by a threaded connection, and the lens base may also be configured as an integral structure with the lens barrel.

Alternatively, the lens assembly 610 may be disposed anywhere in the optical path from the display 120 to the optical fingerprint sensor 200. For example, as shown in FIG. 8, the lens assembly 610 is disposed between the polarization assembly 300 and the 1/4 wave plate 500. Optionally, the lens assembly 610 may also be disposed between the display 120 and the 1/4 wave plate 500, or between the polarizing assembly 300 and the optical fingerprint sensor 200.

Optionally, the second optical component 600 may further comprise a second filter layer 630. Alternatively, the second filter layer may be disposed at any position in the optical path from the display 120 to the optical fingerprint sensor 200. For example, as shown in fig. 8, the second filter layer 630 is disposed between the polarization component 300 and the lens component 610. Optionally, the second filter layer 630 may also be disposed between the display screen 120 and the 1/4 wave plate 500, between the 1/4 wave plate 500 and the lens assembly 610, between a plurality of optical lenses in the lens assembly 610, or between the polarization assembly 300 and the optical fingerprint sensor 200. Alternatively, when the second optical assembly 600 includes a lens barrel, the second filter layer 630 may be disposed in the lens barrel and under the lens assembly 610; when the second optical assembly 600 includes a holder, the second filter layer 630 may also be disposed in the holder and under the lens assembly 610. Optionally, the fingerprint recognition device 20 may further include: and the processing unit is used for processing the group of electric signals to obtain the fingerprint electric signals.

For example, the processing unit is configured to process the first electrical signal and the second electrical signal of the first pixel unit 211 and the second pixel unit 212 to obtain a fingerprint electrical signal, where the fingerprint electrical signal does not have an electrical signal corresponding to natural polarized light and only includes an electrical signal corresponding to fingerprint polarized light.

Alternatively, the processing unit may be a processor, which may be a processor in the optical fingerprint sensor 200, or a processor in an electronic device where the fingerprint recognition device 20 is located, which is not limited in the embodiment of the present application.

Optionally, the fingerprint recognition device 20 may further include: the fingerprint detection device comprises an amplifying unit and an analog-to-digital conversion unit, wherein the amplifying unit is used for receiving and amplifying the fingerprint electric signal to obtain an amplified fingerprint electric signal, and the analog-to-digital conversion unit is used for receiving the amplified fingerprint electric signal and converting the amplified fingerprint electric signal into a digital fingerprint electric signal.

Optionally, any one of the plurality of polarization unit groups includes at least two polarization units, and any one of the plurality of pixel unit groups includes at least two pixel units, where one polarization unit corresponds to at least one pixel unit.

It should be understood that the design and arrangement of each of the plurality of polarization unit groups may be the same or different from each other; one polarization unit may correspond to one or more pixel units; the embodiment of the present application is not limited thereto.

In one possible embodiment, two polarization units with different polarization directions form a polarization unit group, and two pixel units form a pixel unit group, wherein one polarization unit corresponds to the first pixel unit one by one.

Alternatively, as shown in fig. 9a and 9b, a plurality of polarization unit groups may be configured as the polarization assembly 300, and each of the plurality of polarization unit groups may be designed and arranged in the same manner as the first polarization unit group 310, that is, two polarization units in each polarization unit group are identical to two polarization units in the first polarization unit group 310, and the relative positions of the two polarization units in each polarization unit group in the polarization unit group are identical to the relative positions of the two polarization units in the first polarization unit group 310.

Alternatively, as shown in fig. 9c and 9d, each polarization unit group in the polarization assembly 300 may be designed in the same manner as the first polarization unit group 310, that is, two polarization units in each polarization unit group are identical to two polarization units in the first polarization unit group 310. The arrangement of the other polarization unit groups of the plurality of polarization unit groups may be different from that of the first polarization unit group 310, that is, the relative positions of the two polarization units of each polarization unit group in the polarization unit group may be different from that of the two polarization units of the first polarization unit group 310 in the first polarization unit group 310.

Optionally, in the embodiment of the present application, an included angle between the polarization direction of the first polarization unit 311 in the first polarization unit group 310 and the polarization direction of the received fingerprint polarized light signal 304 is α, and an included angle between the polarization direction of the first polarization unit 311 and the polarization direction of the second polarization unit 312 is β.

The first polarization unit 311 and the second polarization unit 312 receive the fingerprint polarized light signal 304 with a light intensity S1, and receive the natural light signal 301 with a light intensity B. After the fingerprint polarized light signal 304 and the natural light signal 301 pass through the first polarization unit 311, the light intensity of the formed first polarized light signal is B/2+s1×cos ² Alpha; after the fingerprint polarized light signal 304 and the natural light signal 301 pass through the second polarization unit 312, the intensity of the formed second polarized light signal is B/2+s1×cos ² (alpha-beta). Optionally, the first pixel unit 211 converts the first polarized light signal into a signal corresponding to the light intensity B/2+s1 ² A first electrical signal of α, the second pixel unit 212 converts the second polarized light signal into a first electrical signal corresponding to the light intensity B/2+S1×cos ² A second electrical signal of (α - β), the first and second electrical signals being a first set of electrical signals corresponding to the first set of polarization units 310 and the first set of pixel units 210.

Among the plurality of polarization unit groups comprising the first polarization unit group, the light intensity of the fingerprint polarized light signal received by the nth polarization unit group in the other polarization unit groups is Sn, n is a positive integer greater than or equal to 2, and the light intensity of the received natural light signal is B. Thus, the nth polarized light signal formed by the nth polarization unit group comprises light intensity of B/2+Sn cos ² Alpha and light intensity of B/2+Sn cos ² (alpha-beta) polarized light signal. Optionally, the nth pixel cell group corresponding to the nth polarization cell group converts the two polarized light signals into two electrical signals, which are the corresponding nth group of electrical signals.

In one possible embodiment, the processing unit subtracts the first electrical signal from the second electrical signal in the first set of electrical signals to obtain a signal corresponding to the light intensity S1 (cos ² α-cos ² (alpha-beta)) and, likewise, two of the nth electrical signal groupThe signals are subtracted to obtain a signal corresponding to the light intensity Sn (cos ² α-cos ² (α - β)).

It should be understood that the included angle α and the included angle β may be any different angle less than 180 °, which is not limited by the embodiment of the present application.

Alternatively, in one possible embodiment, the difference between the included angle α and the included angle β may be 90 °.

For example, as shown in fig. 10a, an included angle between the polarization direction of the first polarization unit 311 and the polarization direction of the received fingerprint polarized light signal 304 is α=0°, and an included angle between the polarization direction of the first polarization unit 311 and the polarization direction of the second polarization unit 312 is β=90°; the polarization assembly 300 includes a plurality of first polarization unit groups 310 arranged in the same manner as in fig. 9c or 9 d. At this time, as shown in fig. 10B, the intensity of the first polarized light signal received by the first pixel unit 211 in the first pixel unit group 210 is B/2+s1, and the intensity of the second polarized light signal received by the second pixel unit 212 is B/2, which is converted into the first group of electrical signals. The light intensity received by the nth pixel unit group is B/2+Sn and B/2, and is converted into two nth group electric signals.

Optionally, in the embodiment of the present application, the fingerprint electrical signal obtained by subtracting the first electrical signal, i.e. the first electrical signal and the second electrical signal, completely corresponds to the fingerprint polarized light signal with the light intensity S1, and the fingerprint electrical signal obtained by subtracting the two electrical signals in the nth electrical signal completely corresponds to the fingerprint polarized light signal with the light intensity Sn.

Optionally, in another possible implementation manner, the processing unit is configured to process the set of electrical signals by adopting a convolution calculation method to obtain the fingerprint electrical signal.

Optionally, in the embodiment of the present application, the processing unit may be further configured to process the plurality of electrical signals by using a convolution calculation method for the plurality of pixel units to obtain a plurality of fingerprint electrical signals.

For example, the intensity of the polarized light signal received by the plurality of pixel unit cell groups is shown in fig. 10b, and the electrical signal processed by the plurality of pixel unit cell groups corresponds to the intensity of the polarized light signal received. The convolution template 100 is shown in fig. 10c, where x is any number not equal to 0. And carrying out convolution calculation on the plurality of groups of electric signals of the plurality of pixel unit groups and the convolution template to obtain a plurality of fingerprint electric signals, wherein the fingerprint electric signals comprise fingerprint polarized light signals corresponding to light intensity of 4x Sn.

In another possible embodiment, four polarization units with different polarization directions form one polarization unit group, and four pixel units form one pixel unit group.

Alternatively, as shown in fig. 11a, the four polarization units with different polarization directions form the second polarization unit group 320, and the design and arrangement of each polarization unit group in the polarization assembly 300 may be the same as that of the second polarization unit group 320, that is, the four polarization units in each polarization unit group are the same as those in the second polarization unit group 320, and the relative positions of the four polarization units in each polarization unit group in the polarization unit group are the same as those of the four polarization units in the second polarization unit group 320.

Alternatively, the polarization unit groups in the polarization assembly 300 may be designed or arranged differently from the second polarization unit group 320, that is, four polarization units in each polarization unit group are different from four polarization units in the second polarization unit group 320, or the relative positions of the four polarization units in each polarization unit group in the polarization unit group are different from the relative positions of the four polarization units in the second polarization unit group 320.

For example, as shown in fig. 11b, a part of the polarization unit groups of the polarization assembly 300 are designed in the same manner as the second polarization unit group 320, but the arrangement of the part of the polarization unit groups is different from that of the second polarization unit group 320.

For example, as shown in fig. 11c, a part of the polarization unit groups of the polarization assembly 300 are designed differently from the second polarization unit groups 320.

Alternatively, in the present embodiment, the second polarization unit group 320 may be a polarization unit group formed by the first polarization unit 311, the second polarization unit 312, and the third polarization unit 313, and the fourth polarization unit 314, and the second polarization unit group 320 may correspond to the second pixel unit group 220 formed by the first pixel unit 211, the second pixel unit 212, and the third pixel unit 213, and the fourth pixel unit 214.

Optionally, in this embodiment of the present application, an included angle between the polarization direction of the first polarization unit 311 and the polarization direction of the received fingerprint polarized light signal 304 is d, an included angle between the polarization direction of the second polarization unit 312 and the polarization direction of the first polarization unit 311 is a, an included angle between the polarization direction of the third polarization unit 313 and the polarization direction of the first polarization unit 311 is b, and an included angle between the polarization direction of the fourth polarization unit 314 and the polarization direction of the first polarization unit 311 is c.

The first polarization unit 311, the second polarization unit 312, the third polarization unit 313 and the fourth polarization unit 314 receive the fingerprint polarized light signal with the light intensity L1, and receive the natural light signal with the light intensity B. After the fingerprint polarized light signal and the natural light signal pass through the first polarization unit 311, the light intensity of the formed first polarized light signal is B/2+l1×cos ² d, a step of; after passing through the second polarization unit 312, the light intensity of the formed second polarized light signal is B/2+l1×cos ² (d-a) passing through the third polarization unit 313 to form a third polarized light signal with a light intensity of B/2+l1×cos ² (d-B) passing through the fourth polarization unit 314 to form a fourth polarized light signal with a light intensity of B/2+l1×cos ² (d-c). Optionally, the first pixel unit 211 converts the first polarized light signal into a signal corresponding to the light intensity B/2+l1 cos ² d, also, the second pixel unit 212 converts the second polarized light signal into a first electrical signal corresponding to the light intensity B/2+L1xcos ² The third pixel unit 213 converts the third polarized light signal into a second electrical signal corresponding to the light intensity B/2+L1xcos ² (d-B) converting the fourth polarized light signal into a third electrical signal corresponding to the light intensity B/2+L1xcos by the fourth pixel unit 214 ² The fourth electrical signal of (d-c).

In the presence of a second polarization sheetAmong the polarization unit groups in the tuple 320, the light intensity of the fingerprint polarized light signal received by the mth polarization unit group in the other polarization unit groups is Lm, m is a positive integer greater than or equal to 2, and the light intensity of the received natural light signal is B. Thus, the mth polarized light signal formed by the mth polarized unit group includes a light intensity of B/2+lm×cos ² d、B/2+Lm*cos ² (d-a)、B/2+Lm*cos ² (d-B) and B/2+Lm cos ² The polarized light signal of (d-c). Optionally, an mth pixel cell group corresponding to the mth polarization cell group converts the four polarized light signals into four electrical signals.

Optionally, in a possible implementation manner, the processing unit subtracts any two electric signals in a group of four electric signals of each pixel unit group to obtain a fingerprint electric signal.

It should be understood that the included angle b, the included angle c, and the included angle d may be any different angle less than 180 °, which is not limited by the embodiment of the present application.

Optionally, in one possible embodiment, as shown in fig. 12a, the polarizing assembly 300 includes a plurality of second polarizing unit groups 320, where an angle between a polarization direction of the second polarizing unit 312 and a polarization direction of the first polarizing unit 311 in the second polarizing unit group 320 is a=45°, an angle between a polarization direction of the third polarizing unit 313 and a polarization direction of the first polarizing unit 311 is b=90°, and an angle between a polarization direction of the fourth polarizing unit 314 and a polarization direction of the first polarizing unit 311 is c=135°. At this time, as shown in fig. 12B, in the second pixel unit group 220 corresponding to the second polarization unit group 320, the intensity of the first polarized light signal received by the first pixel unit 211 is B/2+l1×cos ² d, the intensity of the second polarized light signal received by the second pixel unit 212 is B/2+l1×cos ² (45-d), the third polarized light signal received by the third pixel unit 213 has a light intensity of B/2+l1 sin ² d, the intensity of the fourth polarized light signal received by the fourth pixel unit 214 is B/2+l1×sin ² (45-d). The m-th pixel unit group receives the polarized light signal and converts the polarized light signal to form: corresponding to the light intensity of B/2+Lm cos ² d, corresponding to an electric signal Am of intensity B/2+Lm cos ² (45-d) an electrical signal Bm corresponding to an intensity of B/2+Lm sin ² d has an electrical signal Cm corresponding to a light intensity of B/2+lm sin ² The electric signal Dm of (45-d).

Optionally, in one possible embodiment, the four electrical signals Am, bm, cm and Dm in each pixel cell group are processed as follows: (Am-Bm) ² +(Cm-Dm) ² The unit fingerprint electric signal obtained at this time corresponds completely to the fingerprint polarized light signal with the light intensity Lm.

It should be understood that, in this embodiment, the angle a between the polarization direction of the second polarization unit 312 and the polarization direction of the first polarization unit 311 in the second polarization unit group 320 may also be any angle value greater than 0 ° and less than 90 °, and the angle c=a+90° between the polarization direction of the fourth polarization unit 314 and the polarization direction of the first polarization unit 311.

In the embodiment of the application, by arranging the four polarization units with different polarization directions and processing the electric signals of the corresponding pixel units, the obtained fingerprint electric signals completely correspond to the light intensity Lm ² The fingerprint polarized light signal of the fingerprint sensor has no loss of the light intensity of the fingerprint polarized light signal, and can improve the fingerprint identification performance.

As shown in fig. 13, the embodiment of the present application further provides an electronic device 2, where the electronic device 2 may include the fingerprint recognition device 20 in the embodiment of the application.

Optionally, the electronic device 2 may further include a display screen 120, and the fingerprint recognition device 20 is disposed below the display screen 120.

Optionally, the display screen 120 is an organic light emitting diode OLED display screen or a Micro light emitting diode Micro-LED display screen, and the display screen 120 includes a circular polarizer 122 for converting natural light into circularly polarized light.

It should be appreciated that the processing unit of the embodiments of the present application may be a processor, which may be an integrated circuit chip, with signal processing capabilities. In implementation, the steps of the above method embodiments may be implemented by integrated logic circuits of hardware in a processor or instructions in software form. The processor may be a general purpose processor, a digital signal processor (Digital Signal Processor, DSP), an application specific integrated circuit (Application Specific Integrated Circuit, ASIC), an off-the-shelf programmable gate array (Field Programmable Gate Array, FPGA) or other programmable logic device, discrete gate or transistor logic device, discrete hardware components. The disclosed methods, steps, and logic blocks in the embodiments of the present application may be implemented or performed. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The steps of the method disclosed in connection with the embodiments of the present application may be embodied directly in the execution of a hardware decoding processor, or in the execution of a combination of hardware and software modules in a decoding processor. The software modules may be located in a random access memory, flash memory, read only memory, programmable read only memory, or electrically erasable programmable memory, registers, etc. as well known in the art. The storage medium is located in a memory, and the processor reads the information in the memory and, in combination with its hardware, performs the steps of the above method.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

It will be clear to those skilled in the art that, for convenience and brevity of description, specific working procedures of the above-described systems, apparatuses and units may refer to corresponding procedures in the foregoing method embodiments, and are not repeated herein.

In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other manners. For example, the apparatus embodiments described above are merely illustrative, e.g., the division of the units is merely a logical function division, and there may be additional divisions when actually implemented, e.g., multiple units or components may be combined or integrated into another system, or some features may be omitted or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be an indirect coupling or communication connection via some interfaces, devices or units, which may be in electrical, mechanical or other form.

The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in the embodiments of the present application may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit.

The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application may be embodied essentially or in a part contributing to the prior art or in a part of the technical solution in the form of a software product stored in a storage medium, comprising several instructions for causing a computer device (which may be a personal computer, a server, a network device, etc.) to perform all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a random access Memory (Random Access Memory, RAM), a magnetic disk, or an optical disk, or other various media capable of storing program codes.

The foregoing is merely illustrative of the present application, and the present application is not limited thereto, and any person skilled in the art will readily recognize that variations or substitutions are within the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A fingerprint recognition device, comprising:

an optical fingerprint sensor comprising: the optical fingerprint sensor comprises a pixel array formed by the pixel unit groups and a reading circuit electrically connected with the pixel array;

the 1/4 wave plate is arranged above the plurality of polarization unit groups;

2. The fingerprint identification device according to claim 1, wherein said fingerprint polarized light signal is linearly polarized light after passing through said 1/4 wave plate.

3. The fingerprint recognition device according to claim 1 or 2, wherein the plurality of polarization cell groups are identical.

4. The fingerprint recognition device according to claim 1 or 2, wherein the plurality of polarization unit groups includes a first polarization unit group and a second polarization unit group, the first polarization unit group being different from the second polarization unit group.

5. The fingerprint identification device according to claim 4, wherein the polarization direction of the polarization units in the first polarization unit group is different from the polarization direction of the polarization units in the second polarization unit group.

6. The fingerprint recognition device according to claim 4, wherein the arrangement of the polarization units in the first polarization unit group is different from the arrangement of the polarization units in the second polarization unit group.

7. The fingerprint recognition device of claim 1, wherein any one of the plurality of polarization unit groups comprises at least two polarization units, and any one of the plurality of pixel unit groups comprises at least two pixel units, wherein one polarization unit corresponds to at least one pixel unit.

8. The fingerprint recognition device of claim 1, wherein at least one of the plurality of polarization unit groups comprises a first polarization unit and a second polarization unit, and a difference between polarization directions of the first polarization unit and the second polarization unit is 90 °.

9. The fingerprint identification device of claim 1 wherein said set of electrical signals is used to subtract any two of the different electrical signals to obtain said fingerprint electrical signal.

10. The fingerprint identification device of claim 1, wherein the set of electrical signals is used to perform a convolution calculation to obtain the fingerprint electrical signal.

11. The fingerprint recognition device of claim 1, wherein at least one of the plurality of polarization cell groups comprises a first polarization cell, a second polarization cell, a third polarization cell, and a fourth polarization cell;

12. The fingerprint recognition device of claim 11, wherein the set of electrical signals includes a first electrical signal, a second electrical signal, a third electrical signal, and a fourth electrical signal for calculating the fingerprint electrical signal according to a formula:

13. The fingerprint identification device of claim 1, wherein the fingerprint identification device further comprises:

the first optical component is arranged above the optical fingerprint sensor;

14. The fingerprint identification device of claim 13, wherein the first optical assembly further comprises:

15. The fingerprint identification device of claim 14, wherein the first filter layer is disposed over the plurality of polarization unit groups and the first optical component is disposed over the first filter layer.

16. The fingerprint identification device of claim 1, wherein the fingerprint identification device further comprises:

the second optical component is arranged above the optical fingerprint sensor;

the second optical assembly includes: at least one optical lens.

17. The fingerprint identification device of claim 16, wherein the second optical assembly further comprises:

18. The fingerprint recognition device of claim 16 or 17, wherein the second optical assembly further comprises:

19. The fingerprint recognition device of claim 1, wherein the plurality of polarization cell groups are integrated in the optical fingerprint sensor.

20. The fingerprint identification device of claim 1, wherein the fingerprint identification device further comprises: a processing unit;

21. The fingerprint identification device of claim 1, wherein the fingerprint identification device further comprises: an amplifying unit and an analog-to-digital conversion unit;

22. An electronic device, comprising:

a fingerprint recognition device according to any one of claims 1 to 21.

23. The electronic device of claim 22, further comprising a display screen, the display screen including a circularly polarizing plate therein;

the fingerprint identification device is arranged below the display screen.