CN111582131B

CN111582131B - Thin type under-screen optical fingerprint identification device and fingerprint identification method

Info

Publication number: CN111582131B
Application number: CN202010361610.XA
Authority: CN
Inventors: 程泰毅; 张骁驰; 谢詹奇; 李淑娟
Original assignee: Silead Inc
Current assignee: Silead Inc
Priority date: 2020-04-30
Filing date: 2020-04-30
Publication date: 2023-10-27
Anticipated expiration: 2040-04-30
Also published as: CN111582131A

Abstract

The invention provides a thinned under-screen optical fingerprint identification device and a fingerprint identification method, wherein the device comprises a light detection array with a photosensitive area, a photosensitive pixel array arranged on the photosensitive area comprises a plurality of photosensitive pixel points, the photosensitive pixel points comprise at least two types of sub-pixel units, and at least two different filter layers are arranged on the at least two types of sub-pixel units; a cover layer over the light detection array; the point light source array comprises at least two types of excitation light sources, the detection light emitted to the object to be identified illuminates a high-contrast area on the covering layer, and the inner circle boundary and the outer circle boundary of the high-contrast area respectively correspond to the detection light of the first critical angle and the second critical angle; the signal light reflected by the object to be identified reaches the corresponding sub-pixel unit after passing through the filter layer. The under-screen optical fingerprint identification device can collect fingerprint signals without arranging a lens or a micro lens, is thinner, and is beneficial to the light and thin design of electronic equipment.

Description

Thin type under-screen optical fingerprint identification device and fingerprint identification method

Technical Field

The invention relates to the field of fingerprint identification, in particular to a thinned under-screen optical fingerprint identification device and a fingerprint identification method.

Background

The optical fingerprint identification under the screen can be applied to electronic equipment including, but not limited to, a smart phone or other electronic equipment with man-machine interaction functions. As shown in fig. 1 and 2, the conventional under-screen fingerprint module is generally disposed below a display screen 1 of an electronic device, and includes at least a fingerprint chip 3. The excitation light source for implementing the under-screen optical fingerprint recognition may be a self-luminous display screen 1, such as an OLED screen, which is self-contained in the electronic device. The display screen 1 emits detection light to the finger of the user, and the detection light is reflected by the finger of the user to form signal light carrying fingerprint information of the user, and the signal light propagates downwards to reach the fingerprint chip 3. The fingerprint chip 3 performs photoelectric signal conversion to obtain a fingerprint image containing finger valley and finger ridge information.

As shown in fig. 1, in a known embodiment, signal light is converged onto a fingerprint chip 3 through a lens 2 provided between a display screen 1 and the fingerprint chip 3. Alternatively, as shown in fig. 2, in another known embodiment, the signal light is finally converged on the fingerprint chip 3 through the micro lens 4 provided on the fingerprint chip 3.

The under-screen fingerprint module of the above two known embodiments needs a lens module or a micro-lens structure between the fingerprint chip and the display screen, which results in a complex structure of the fingerprint identification module and high process cost. In addition, because a lens module or a micro-lens structure is required between the fingerprint chip and the display screen, the fingerprint identification module is thicker, and the thinning of the electronic equipment is not facilitated.

Disclosure of Invention

Based on the defects in the prior art, the embodiment of the invention provides the thinned under-screen optical fingerprint identification device and the fingerprint identification method, a lens module or a micro-lens structure is not required to be arranged on a fingerprint chip and a display screen bracket, fingerprint signal acquisition can be realized, and the thickness is thinner, so that the thinned under-screen optical fingerprint identification device and the fingerprint identification method are beneficial to the thin and light design of electronic equipment.

In order to achieve the above object, the present invention provides the following technical solutions.

A slim underscreen optical fingerprint recognition device, comprising:

the light detection array is provided with a photosensitive area, and a photosensitive pixel array is arranged on the photosensitive area; the photosensitive pixel array comprises a plurality of photosensitive pixel points, each photosensitive pixel point comprises at least two types of sub-pixel units, and at least two different filter layers are correspondingly arranged on the surfaces or above the at least two types of sub-pixel units;

the covering layer is positioned above the light detection array, and the upper surface of the covering layer is used for enabling an object to be identified to be contacted;

the point light source array is positioned between the light detection array and the covering layer and comprises at least two excitation light sources for emitting detection light with at least two different wave bands to an object to be identified;

when the thinned under-screen optical fingerprint identification device detects that an object to be identified is contacted with the cover layer, detection light emitted by each excitation light source to the object to be identified correspondingly illuminates a circular high-contrast area on the cover layer, the inner circle boundary of the high-contrast area corresponds to detection light of a first critical angle, and the outer circle boundary corresponds to detection light of a second critical angle; the signal light reflected by the object to be identified by the detection light passes through the filter layer and then reaches the corresponding sub-pixel unit; wherein the surface of the object to be identified is formed with valleys and ridges, a gap is formed between the valleys and the covering layer, and the ridges are in contact with the covering layer; the first critical angle corresponds to the angle of total reflection of light at the interface of the cover layer and the gap, and the second critical angle corresponds to the angle of total reflection of light at the interface of the cover layer and the ridge.

A fingerprint identification method by using the thinned under-screen optical fingerprint identification device according to the embodiment comprises the following steps:

when the contact of the object to be identified on the cover layer is detected, controlling the operation of the at least two types of excitation light sources to emit detection light to the object to be identified, wherein the detection light emitted by each excitation light source correspondingly illuminates a ring-shaped high-contrast area on the cover layer, and the signal light reflected by the object to be identified reaches the corresponding sub-pixel unit after passing through the filter layer;

the sub-pixel units sense the intensity of the signal light and output image fragments with different colors;

synthesizing a full fingerprint image in a color sequence based on the plurality of image segments;

and matching the synthesized full fingerprint image with a pre-stored fingerprint image to judge whether the object to be identified is a real finger of a user.

According to the thin type under-screen optical fingerprint identification device and the fingerprint identification method, the obtained fingerprint pattern can be directly received and sensed by the light detection array through the special design of the excitation light source. Therefore, a lens module or a micro lens structure for converging signal light in the prior art is omitted or omitted, so that the thickness of the fingerprint identification device is thinner and lighter, and the design of lightening and thinning of electronic equipment is facilitated. In addition, the fingerprint identification device has simplified structure and greatly reduced manufacturing cost.

In addition, the thinned under-screen optical fingerprint identification device and the fingerprint identification method provided by the embodiment of the invention can be used for acquiring color fingerprint images by utilizing a plurality of optical cocoa with different wave bands and different incident angles, and restoring three-dimensional or stereoscopic fingerprint characteristics, so that the anti-counterfeiting effect is better.

Specific embodiments of the invention are disclosed in detail below with reference to the following description and the accompanying drawings, indicating the manner in which the principles of the invention may be employed. It should be understood that the embodiments of the invention are not limited in scope thereby.

Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments in combination with or instead of the features of the other embodiments.

It should be emphasized that the term "comprises/comprising" when used herein is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps or components.

Drawings

The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. In addition, the shapes, proportional sizes, and the like of the respective components in the drawings are merely illustrative for aiding in understanding the present invention, and are not particularly limited. Those skilled in the art with access to the teachings of the present invention can select a variety of possible shapes and scale sizes to practice the present invention as the case may be. In the drawings:

FIG. 1 is a schematic diagram of a fingerprint identification structure in a known embodiment of the prior art;

FIG. 2 is a schematic diagram of a fingerprint recognition structure according to another known embodiment of the prior art;

FIG. 3 is a schematic diagram of a slim underscreen optical fingerprint recognition device according to one non-limiting embodiment of the present invention;

FIG. 4 is a block diagram of a slim underscreen optical fingerprint identification device in accordance with one non-limiting embodiment of the present invention;

FIG. 5 is a light path diagram of a slim underscreen optical fingerprint recognition device in accordance with one non-limiting embodiment of the present invention;

FIG. 6 is a schematic diagram of a structure in which a point light source array included in a thinned under-screen optical fingerprint recognition device according to one non-limiting embodiment of the present invention is formed on a light-emitting layer of a self-luminous display screen;

FIG. 7 is a schematic view of the optical path when the incident angle of the probe light is larger than the first critical angle;

FIG. 8 is a schematic view of the optical path when the incident angle of the probe light is larger than the second critical angle;

FIG. 9 is an image of an actually acquired fingerprint;

FIG. 10 is a schematic diagram of a non-limiting embodiment of a point light source array comprising two different types of excitation light sources and a high contrast area formed by two adjacent excitation light sources on a cover layer;

FIG. 11 is a schematic view of a non-limiting embodiment of a point light source array comprising three different types of excitation light sources and a high contrast area formed by two adjacent excitation light sources on a cover layer;

FIG. 12 is a schematic diagram of the structure of two high-recognition areas formed on the photosensitive area of the light detection array by two different signal lights in one non-limiting embodiment;

FIG. 13 is a schematic diagram of a photo-detection array and a photosensitive pixel array included in the photo-detection array and a filter layer disposed on the photosensitive pixel array according to a non-limiting embodiment;

FIG. 14 is a flow chart of a fingerprint identification method according to one non-limiting embodiment of the present invention;

FIG. 15 is a flowchart of a fingerprint identification method according to another non-limiting embodiment of the invention;

fig. 16 is a flowchart of acquiring a 3D fingerprint image in the embodiment shown in fig. 15.

Detailed Description

In order to make the technical solution of the present invention better understood by those skilled in the art, the technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, shall fall within the scope of the invention.

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

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

In view of the prior art embodiment as shown in fig. 1 and fig. 2, the fingerprint identification structure needs to be provided with a lens module or a micro lens structure between the fingerprint chip and the display screen, so that the overall thickness of the fingerprint identification structure is thicker, which is not beneficial to the structural design of the electronic device for lightening and thinning, the embodiment of the invention provides a thinned under-screen optical fingerprint identification device (for convenience of description, hereinafter simply referred to as the device) as shown in fig. 3. The device can directly receive and sense the obtained fingerprint pattern by the light detection array through the special design of the excitation light source. Therefore, a lens module or a micro lens structure for converging signal light in the prior art is eliminated, so that the thickness of the fingerprint identification device is thinner and lighter, and the design of lightening and thinning of electronic equipment is facilitated. In addition, the fingerprint identification device has simplified structure and greatly reduced manufacturing cost.

As shown in fig. 4, the apparatus may be employed or configured in an electronic device 100 including, but not limited to, a smart phone, a tablet electronic device, a computer, a GPS navigator, a smart wearable device, a personal digital assistant, and the like. The following description will mainly describe the case where the device is applied to a smart phone, but it should be understood that the scope of the embodiments of the present invention is not limited thereto.

According to various embodiments of the present invention, the present device may include a light detection array 5, a cover layer 6 over the light detection array 5, and an array of point light sources between the light detection array 5 and the cover layer 6. That is, the cover layer 6, the point light source array, and the light detection array 5 are disposed in this order from top to bottom.

The light detection array 5 may be part of a fingerprint chip. The fingerprint chip may include photosensitive area with photosensitive pixel array and non-photosensitive area. Thus, in the present embodiment, a portion of the fingerprint chip where the photosensitive pixel array is provided may be defined as the light detection array 5. That is, the photosensitive region of the light detection array 5 is provided with a photosensitive pixel array. As shown in fig. 4, 5, and 13, in some possible embodiments, the photosensitive pixel array includes photosensitive pixel dots 501 that may be arranged in a rectangular array mxn, for receiving signal light and sensing the intensity of the signal light.

The light detection array 5 is arranged below the array of point light sources. Specifically, the electronic device 100 such as a smart phone is provided with a center through which the fingerprint chip is disposed below the point light source array, and the fixation of the light detection array 5 is achieved. The light detection array 5 is used for converting the received light signals into electrical signals to generate a fingerprint image, and further may send the fingerprint image to an image data processing unit in signal connection with the photosensitive pixel array. The image data processing unit can be a module independent of the fingerprint chip, can also be integrated in the fingerprint chip, and can be arranged in a non-photosensitive area. The image data processing unit may perform image processing to obtain a fingerprint pattern and supply the generated fingerprint pattern to a processor in signal connection therewith. The processor can compare and match the generated fingerprint pattern with a standard fingerprint pattern stored in the processor in advance so as to judge whether the object to be identified is the real finger of the user.

Specifically, the smart phone pre-records fingerprint image information of the real finger of the user and stores the fingerprint image information in a local information base, namely a processor. And when fingerprint identification is carried out, comparing the generated fingerprint image with standard fingerprint images stored in an information base. And when the comparison result shows that the similarity of the two images reaches the set threshold value, the generated fingerprint image is considered to be matched with the standard fingerprint image, and the current object to be identified is judged to be the real finger of the user. Subsequently, the smart phone completes screen unlocking, rights acquisition through (e.g., payment, login, etc. scenarios), and the like.

Otherwise, if the comparison result shows that the similarity of the two images is lower than the set threshold value, the generated fingerprint image is not matched with the standard fingerprint image, and the current object to be identified is judged to be the printed fingerprint image, the imitated fingerprint film or the fingerprint film or other attack artificial limbs. The smart phone continues to maintain the current screen locking, the failure of rights acquisition and other operation interfaces unchanged.

In this embodiment, the standard fingerprint image stored in advance in the processor may be changed accordingly according to the type of the generated image. For example, in some embodiments, the image generated by the device is a full fingerprint image, and the pre-recorded standard image information stored in the processor includes the full fingerprint image, which is used for performing matching comparison with the full fingerprint image generated by the device to determine whether the object to be identified is a real finger of the user.

Of course, in order to enhance the anti-counterfeiting performance of fingerprint identification, as described below, in some further embodiments, the image generated by the device may also be a three-dimensional fingerprint image, or the generated image may reflect skin color information of the object to be identified. Correspondingly, the pre-recorded and stored standard image information in the processor can further comprise three-dimensional stereo images or skin color information, and the three-dimensional stereo fingerprint image information and the skin color information are used for matching and comparing with the three-dimensional stereo fingerprint image and the skin color information provided by the device so as to judge whether the object to be identified is the real finger of the user or not, and the anti-counterfeiting performance of the identification effect is enhanced.

In this embodiment, the processor may be provided in the electronic device. Thus, the device generates a fingerprint image and provides the generated fingerprint image to a processor of the electronic device for recognition. That is, the device is responsible for collecting and generating fingerprint images, and the processor performs recognition according to the generated fingerprint images.

With continued reference to fig. 4, the overlay 6 has a contact area for contacting or pressing an object to be identified (e.g., a user's finger, a printed fingerprint pattern, a simulated fingerprint film, etc.). Since the probe light emitted from the point light source array is required to irradiate the object to be identified pressed on the contact area, the arrangement of the cover layer 6 will not affect the light path, and is generally made of a light-transmitting material. But is not limited to, in other embodiments, the cover layer 6 is not necessarily limited to a fully transparent material due to the particular design.

The cover layer 6 is disposed above the point light source array, and may be a protective cover plate for protecting the point light source array, including a cover glass or a sapphire cover plate, etc. Further, in some embodiments, the upper surface of the cover layer 6 may also be provided with a protective layer, such as a protective film. In the embodiment of the invention, therefore, the so-called object to be identified is brought into contact with or pressed against the cover layer 6, and may in fact be pressed directly against the cover layer 6 or against a protective layer.

As shown in connection with fig. 6, the array of point light sources comprises at least two types of excitation light sources for emitting detection light of at least two different wavelength bands towards the object to be identified contacting the cover layer 6. Since the wavelength band of light corresponds to the color of light, the wavelength band difference of the detection light is embodied as the color difference of the detection light.

Further, in order that the signal light formed by the detection light emitted by a certain type of excitation light source after being reflected by the object to be identified can only be received by a specific sub-pixel unit through the corresponding filter layer, in some preferred embodiments, the wave bands of the detection light emitted by any two types of excitation light sources are not overlapped. For example, in some non-limiting scenarios, the first type of excitation light source 701 emits detection light that is red (band range 610-760 nm), the second type of excitation light source 702 emits detection light that is green (band range 510-550 nm), and the third type of excitation light source 703 emits detection light that is blue (band range 430-490 nm). Because the filter layer can only effectively filter light rays in a specific wave band, different types of excitation light sources are adopted to emit visible detection light which is separated from each other in frequency spectrum, and crosstalk generated by detection emitted between adjacent excitation light sources can be effectively avoided.

As shown in fig. 4, in a possible embodiment, the cover layer 6 and the array of point light sources may be disposed on a self-luminous display screen configured by an electronic device 100 (e.g., a smart phone) to which the present apparatus is applied, for example, an OLED screen or an LED screen. Or, in other words, the cover layer 6 and the point light source array are constituted by a partial area of the self-luminous display screen with which the electronic device 100 itself of the present apparatus is equipped. The self-emissive display may comprise a light emitting layer 7, for example an OLED light emitting layer or an LED light emitting layer. The partial region of the light-emitting layer 7 corresponding to the cover layer 6 constitutes a disposition region of the point light source array.

Referring to fig. 6, the light emitting layer 7 includes a plurality of self-luminous light emitting pixel units 704, and the light emitting pixel units 704 may also be arranged in an m×n matrix, where each light emitting pixel unit 704 includes an RGB light emitting pixel array. The light emitting pixel units 704 are caused to emit light of a corresponding color by modulating RGB values of the RGB light emitting pixel arrays within each light emitting pixel unit 704. For example, if all R (red) pixels and none of G (green) and B (blue) pixels in the light-emitting pixel unit 704 are operated, the light-emitting pixel unit 704 emits monochromatic red light. Similarly, if all the G pixels in the pixel 704 are operated and none of the R, B pixels are operated, the pixel 704 emits monochromatic green light. All the B pixels in the light emitting pixel unit 704 are operated, while none of the R, G pixels are operated, and the light emitting pixel unit 704 emits blue light of a single color. Alternatively, all R, G, B pixels in the pixel 704 are operated, and the RGB values are 255, so that the pixel 704 emits white light with multiple colors.

In a possible embodiment, the excitation light source may comprise one light emitting pixel unit 704, i.e. one light emitting pixel unit 704 constitutes one excitation light source. Alternatively, as shown in fig. 6, in another possible embodiment, the excitation light source may include a plurality of light emitting pixel units 704, i.e., the plurality of light emitting pixel units 704 together form one excitation light source. At this time, the excitation light source is a cluster group composed of a plurality of adjacent light emitting pixel units 704.

According to various embodiments of the present invention, the detection light emitted by the excitation light source may be monochromatic, e.g. red, blue or green light. The RGB pixel array in the one or more pixel units 704 included in the excitation light source has the target pixel point operating instead of the target pixel point not operating. For example, when one of the excitation light sources is to emit red detection light, the target pixel in the RGB light-emitting pixel array is an R pixel, and the G, B pixel is a non-target pixel.

Similarly, if another excitation light source is to emit green detection light, the target pixel point in the RGB light-emitting pixel array is a G pixel point, and the R pixel point and the B pixel point are non-target pixel points. Or if another excitation light source is to emit blue detection light, the target luminous pixel point in the RGB luminous pixel array is a B pixel point, and the R pixel point and the G pixel point are non-target luminous pixel points.

As shown in fig. 4, the number of each type of excitation light source is plural, and at least two types of excitation light sources are alternately arranged. For example, excitation light sources located in the same column or row, adjacent two excitation light sources not belonging to the same class. That is, in this embodiment, not all the light-emitting pixel units 704 included in the light-emitting layer 7 of the self-light-emitting display screen are used as the excitation light source, but a part of all the light-emitting pixel units 704 is selected as the excitation light source, and the other light-emitting pixel units 704 not used as the excitation light source do not emit light (go out) when the present device is in an operating state, but emit light in a resting state. Also, when normal display is required, all the light emitting pixel units (including the light emitting pixel units as the excitation light source and the light emitting pixel units not as the excitation light source) preferably emit white light for display.

The working state may be a state when fingerprint identification is performed. Accordingly, the rest state is a state when no fingerprinting is required or performed. For example, the display screen 8 is a touch display screen, which can switch the operation mode of the device from the current mode to the operation state based on actions such as approaching, touching, pressing, etc. of the object to be identified or internal program instructions of the electronic device 100. After the fingerprint identification is completed, the working mode of the device is switched to a resting state.

For example, in a scenario where screen unlocking is required for a smart phone, the current black screen state of the smart phone is a rest state. When the display 8 detects the approaching, touching, pressing, etc. actions of the object to be recognized, the light-emitting pixel units 704 serving as the excitation light sources in the light-emitting layer 7 emit light (for example, monochromatic light), while the other light-emitting pixel units 704 not serving as the excitation light sources emit no light, so that the cover layer 6 is illuminated. When the object to be identified pressed on the cover layer 6 is the real finger of the user, the fingerprint identification is successful, and the screen unlocking is completed. Then, the other light-emitting pixel units 704 which are not used as the excitation light sources restore light emission (preferably white light), so that the light-emitting pixel units 704 which are used as the excitation light sources restore light emission to emit white light for light intensity supplement, and uniform display of the picture is realized.

For another example, in a scenario where the smart phone performs fingerprint payment, the current awake state of the smart phone is a rest state. At this time, the light emitting layer 7 includes all the light emitting pixel units 704 emitting white light. When the payment interface or payment control pops up, those light emitting pixel units 704 that are not excitation light sources go off or decrease in brightness, while the light emitting pixel units 704 that are excitation light sources continue to operate (specifically, different types of excitation light sources emit monochromatic light of different wavelength bands or colors), thereby illuminating the cover layer 6. When the object to be identified pressed on the cover layer 6 is the real finger of the user, the fingerprint identification is successful, and the payment is completed. Then, the other light-emitting pixel units 704 which are not used as the excitation light sources resume light emission (preferably white light), and the light emission of the light-emitting pixel units 704 which are used as the excitation light sources also resume light emission again, so that the mobile phone interface is normally displayed.

With the above design, when the device is actually applied to the electronic apparatus 100, the emission of the probe light can be realized without setting an additional light source, so that the volume of the device can be reduced, and the design of lightening and thinning of the electronic apparatus 100 is facilitated.

In the above embodiment, the display screen 8 may further be a touch display screen, which not only can perform screen display, but also can detect a touch or press operation of a user, and provide a man-machine interaction interface for the user. Moreover, the touch display screen can detect the approach, pressing or contact of an object to be identified, so as to control the working mode of the device, namely whether the excitation light source is operated or not. In a specific embodiment, the electronic device 100 may be configured with a touch sensor, specifically a touch panel, which may be disposed on a surface of the display screen 8, or may be partially integrated or integrally integrated inside the display screen 8, so as to form the touch display screen.

Of course, the point light source array is not limited to the above embodiment, and other possible embodiments may include an additional light emitting device, and the emitted detection light may be visible light or invisible light, for example, an LED (for implementing visible light), an infrared light source, an ultraviolet light source, a far infrared light source (for implementing invisible light), etc., which is not limited in this embodiment. In the embodiment in which the excitation light source included in the point light source array is composed of an additionally provided light emitting device, the display screen 8 configured by the electronic apparatus 100 using the device is only used for picture display and man-machine interaction, and is not used for emitting probe light.

According to various embodiments of the present invention, the photosensitive pixel dots 501 arranged in a rectangular array mxn form included in the photosensitive pixel array include at least two types of sub-pixel units, and at least two different filter layers are correspondingly disposed on or above the surfaces of the at least two types of sub-pixel units. Alternatively, it can be said that the pixel units included in the photosensitive pixel point 501 are divided into different types of sub-pixel units by providing different types of filter layers in different location areas of the entire photosensitive pixel array. For example, if a red (R) filter layer is disposed on some areas of the photosensitive pixel 501, red sub-pixel units are formed under the areas, and only red signal light is sensed and received. Alternatively, a green (G) filter layer is disposed on other areas of the photosensitive pixel 501, and a green sub-pixel unit is formed under the area, and only green signal light is sensed and received. Alternatively, a blue (B) filter layer is disposed on other areas of the photosensitive pixel 501, so that a blue sub-pixel unit is formed under the area, and only the blue signal light is sensed and received.

The principle of fingerprint imaging using the above-described device of an embodiment of the present invention is described below.

According to the principle of total reflection, when light enters an optically-dense medium from the optically-sparse medium, the refraction angle reaches 90 degrees when the incident angle is increased to a certain critical angle, the refracted light rays disappear, and all incident light rays are reflected back to the optically-dense medium without being transmitted into the optically-sparse medium. The critical angle is the total reflection angle and is marked as theta.

As shown in fig. 5, 7 and 8, taking the object to be identified as a user's finger as an example, when the user's finger is pressed against the overlay 6, a gap (typically an air gap) is formed between the fingerprint valleys and the overlay 6, and the fingerprint ridges are in contact with the overlay 6. In general, it is difficult for the user's finger to achieve a tight dryness. Thus, there is typically perspiration between the fingerprint ridge and the overlay 6. The air gap and the skin tissue or perspiration of the human body are photophobic media with respect to the cover layer 6 (typically glass). Whereas skin tissue or perspiration of the human body is a light tight medium with respect to the air gap.

The calculation formula according to the total reflection angle is as follows:

where n2 is the refractive index of the photophobic medium, and corresponds to the refractive index of the cover layer 6 in this embodiment. n1 is the refractive index of the optically dense medium, corresponding to the refractive index of the air gap or the skin tissue of the finger in this embodiment; when sweat stains exist on the finger, the refractive index of the sweat stains (liquid) is corresponding.

From this, it is understood that the larger the refractive index of the optically thinner medium is, the larger the corresponding total reflection angle is.

Specifically, referring to fig. 5, the total reflection angle of the light at the interface of the air gap of the cover layer 6 and the fingerprint valley is denoted as a first critical angle θ1, and the total reflection angle of the light at the interface of the cover layer 6 and the fingerprint ridge is denoted as a second critical angle θ2. From the above analysis, the first critical angle θ1 is smaller than the second critical angle θ2.

When the incident angle of the probe light is smaller than the first critical angle θ1, the incident light is partially reflected and partially refracted at the fingerprint valleys and fingerprint ridges, and most of the refracted light reaches the finger surface. Light refracted at the fingerprint valley is reflected by the skin of the fingerprint valley, and reflected twice, three times or more at the interface between the air gap and the cover layer 6, so that more loss is caused. Therefore, the fingerprint image obtained in this case exhibits a valley-ridge effect and is inferior in contrast.

In short, a better fingerprint image cannot be obtained just above the excitation light source, such as the central bright spot or bright spot illustrated in fig. 9.

As shown in fig. 7, the light path diagram is the light path diagram when the incident angle of the probe light emitted from the excitation light source is larger than the first critical angle θ1 but smaller than the second critical angle θ2. At this time, the probe light is totally reflected at the fingerprint valleys, but is partially reflected+partially refracted at the fingerprint ridges. At this time, the obtained fingerprint image has a valley ridge dark effect and the light-dark contrast is optimal. Therefore, the illuminated area of the cover layer 6 when the probe light satisfies such an incident angle is referred to as a high contrast area 601.

As shown in connection with fig. 10, the detection light emitted by each excitation light source (701, 702) illuminates a corresponding one of the high contrast areas 601 on the cover layer 6. The high-contrast area 601 is in a circular shape, and comprises two concentric circle boundaries with the excitation light sources (701, 702) as the centers of the circles, and the circular area defined between the two concentric circles is the high-contrast area 601. Wherein the inner circle boundary corresponds to the detection light of the first critical angle θ1, and the outer circle boundary corresponds to the detection light of the second critical angle θ2.

As shown in fig. 8, an optical path diagram is shown when the incident angle of the probe light emitted from the excitation light source is larger than the second critical angle θ2. Then, the probe light is totally reflected at both the fingerprint ridges and the fingerprint valleys, so that the fingerprint ridges and the fingerprint valleys exhibit no or little difference. Thus, the fingerprint image is not obtained at a distance from the excitation light source, as in the edge-blurred region illustrated in fig. 9.

In embodiments in which the excitation light source is formed by a light emitting pixel unit 704 in a display screen 8 carried by the electronic device 100 employing the present apparatus, the light emitting pixel unit 704 included in the light emitting layer 7 of the display screen 8 is not particularly modified. Then, when the excitation light source is operated, a surface light is emitted. That is, the angle of the light emitted by the excitation light source is non-selective or arbitrary. The light source includes not only the unnecessary light having an incident angle smaller than the first critical angle θ1 and larger than the second critical angle θ2, but also the useful probe light having an incident angle between the first critical angle θ1 and the second critical angle θ2. However, as described above, the light having an incident angle greater than the second critical angle θ2 cannot obtain a fingerprint image, and thus is negligible. And the area illuminated by the light having an incident angle smaller than the first critical angle θ1 is the inner circular area of the high-contrast area 601. As can be seen from the above description, the ridge-valley characteristics of the fingerprint image obtained in this inner circular region are diametrically opposed to the ridge-valley characteristics of the fingerprint image obtained in the high contrast region 601. Therefore, for convenience of explanation, the inner circular region of the high contrast region 601 is named as the inversion region 602.

As described above, within the reverse region 602, a superior fingerprint image cannot be obtained by means of the corresponding excitation light source alone. Thus, adjacent excitation light sources may be used to supplement the area. Specifically, as shown in fig. 10, the high contrast region 601 covers an inner circular region of the adjacent high contrast region 601. In this way, the opposite region 602 is covered by the adjacent high-contrast region 601, so that part of the position of the object to be identified in the opposite region 602 is irradiated by the adjacent high-contrast region 601, thereby realizing the acquisition of the fingerprint image in the opposite region 602, ensuring that the fingerprint image can be acquired in a higher quality everywhere, and further ensuring that the quality of the finally obtained fingerprint image is better.

When it is detected that an object to be identified on the cover layer 6 is in contact, the device is switched to a working state, at this time, at least two types of light sources start to operate to emit light, and probe light is emitted to the object to be identified pressed on the cover layer 6. When the incident angle of the probe light is between the first critical angle θ1 and the second critical angle θ2, the object to be identified located in the high-contrast area 601 reflects the probe light downward to form signal light carrying fingerprint information. After the signal light propagates downwards and is filtered by the filter layer, the rest signal light reaches the corresponding sub-pixel unit. Therefore, the same kind of sub-pixel units receive the signal light of the same wave band, and the different kinds of sub-pixel units receive the signal light of different wave bands, so that the acquisition of fingerprint images is realized.

As can be seen from fig. 5, in the case where the positions of the excitation light sources (701, 702) included in the point light source array are unchanged, the thickness of the cover layer 6 may have an influence on the area size of the high-contrast region. Specifically, when the position of the excitation light sources (701, 702) is unchanged, the thickness of the cover layer 6 increases, and the areas of the high contrast areas 601 illuminated on the cover layer 6 by the probe light of the first critical angle θ1 and the second critical angle θ2 also increase. The arrangement density of the excitation light sources also affects the number of high-contrast regions 601 to be generated, and further affects whether or not the high-contrast regions 601 cover the adjacent inversion regions 602. Thus, in the present embodiment, the purpose of the high contrast region 601 covering the adjacent counter region 602 can be achieved by adjusting the thickness of the cover layer 6 and/or the arrangement density of the excitation light sources.

In some known embodiments, the light emitting pixels for emitting the probe light and the light sensing pixels for sensing light are disposed on the same layer, both on the light emitting layer of the display screen. That is, the pixel points on the light emitting layer include light emitting pixel points and light sensing pixel points, and these light sensing pixel points may also emit light. That is, when fingerprint identification is required, the photosensitive pixels are used for photosensitive, and when a picture is displayed without fingerprint identification, the photosensitive pixels normally emit light. However, in this known embodiment, some specific pixels included in the light emitting layer need to be switched back and forth in two working modes of light sensing and light emitting, which is difficult to implement, and the algorithm and control procedure are complex. Therefore, the cost is high, and the popularization and the application in large area are difficult in practice.

In the embodiment of the present invention, the light emitting pixel point for emitting the detection light and the light sensing pixel point 501 for sensing light are layered, and the two different functional pixel points are layered in two layers. Therefore, the functions or actions of the two pixel points are simple and pure, the algorithm and the control program are relatively simple, the preparation cost is low, and the method is suitable for practical application.

In fact, all excitation light sources emit detection light with the same wave band, and fingerprint image acquisition can be realized. However, in order to enable the photosensitive pixel 501 to collect the signal light at a corresponding angle, when all the excitation light sources emit the detection light in the same band range, each excitation light source needs to be operated to emit sequentially, but all the excitation light sources cannot emit light at the same time. Otherwise, the photosensitive pixel 501 cannot distinguish from which angle the received signal light is reflected, and thus confusion is caused and imaging cannot be performed. Because the excitation light sources need to emit light in sequence, the fingerprint identification can be completed only in a long time by adopting the mode, the response time of the fingerprint identification is long, the efficiency is low, and the user experience is poor.

In view of this, in order to improve the fingerprint recognition efficiency, in this embodiment, the excitation light sources are configured to be at least two types, and the at least two types of excitation light sources emit detection light with different wavebands, and signal light with different wavebands (colors) can reach the corresponding sub-pixel units by means of the corresponding filter layers. Therefore, the photosensitive pixel 501 is made to discriminate the detection light of different angles by using the signal light of different wave bands, so that the problem of mutual interference of the signal light does not exist. Then, at least two types of excitation light sources may emit light simultaneously when the device is in operation. Therefore, at least two types of sub-pixel units can simultaneously receive and sense signal lights in different wave bands, the response speed of fingerprint identification is high, the identification efficiency is high, and the user experience can be greatly improved.

As shown in fig. 4, 5, 6, and 10, in a specific embodiment, the excitation light source may include two types: the first type excitation light source 701 and the second type excitation light source 702 are configured to emit detection light in a first wavelength band and a second wavelength band, respectively. The filter layer corresponds to two types: the first type filter layer 901 and the second type filter layer 902 are used for allowing the signal light of the first wave band and the second wave band to pass through, and filtering the signal light of other wave bands.

More specifically, in one illustrative scenario, the first type of excitation light source 701 may be a red (R) excitation light source, with the first wavelength band being the red wavelength band. The second type of excitation light source 702 may be a green (G) excitation light source, with the first wavelength band being the green wavelength band. Correspondingly, the first type of filter layer 901 is a red (R) filter layer, and the sub-pixel units below the filter layer are red pixel units; the second type of filter 902 is a green (G) filter, and the sub-pixel below it is a green pixel. When fingerprint identification is required, the red signal light formed by the red detection light emitted by the first excitation light source 701 after being reflected by the object to be identified can only be received and sensed by the red pixel unit, but cannot reach the green pixel unit. Similarly, the green signal light formed by the green detection light emitted by the second type excitation light source 702 after being reflected by the object to be identified can only be received by the green pixel unit, but cannot reach the red pixel unit. Therefore, a plurality of light sources contained in each excitation light source are operated to emit light simultaneously, and the signal light can be received and sensed by the corresponding sub-pixel units, so that the problem of signal light crosstalk is avoided.

As shown in fig. 12, the signal light formed by the reflection of the probe light emitted from the excitation light source by the object to be recognized also illuminates a high recognition area 502 having a ring shape on the photosensitive pixel array. As described above, the high recognition area 502 is defined by two concentric circles with the excitation light source as the center, and the annular area defined between the two concentric circles is the high recognition area 502. The inner circle boundary corresponds to the signal light reflected by the detection light of the first critical angle theta 1, and the outer circle boundary corresponds to the signal light reflected by the detection light of the second critical angle theta 2.

As can be seen from the formation of the high-definition region 502, the sub-pixel units covered by the high-definition region 502 receive and sense the signal light reflected by the high-contrast region 601. Accordingly, the area defined by the inner circular boundary of the high identification area 502 receives and senses the signal light reflected by the reverse area 602. For convenience of explanation, the area defined by the inner circular boundary of the high recognition area 502 is named as an embedded area 503.

In this embodiment, the filter layer on the surface of the photosensitive area is provided by non-selective blind-paste. Thus, at least two different filter layers are provided on the area covered by the high recognition area 502 and the embedded area 503, as shown in fig. 13.

Referring to fig. 5, the signal light emitted from the same excitation light source (701, 702) and having an incident angle between the first critical angle and the second critical angle is reflected by the object to be identified, and propagates obliquely downward. Thus, as the optical path length increases, the distance by which the signal light deviates from the corresponding high contrast region 601 gradually increases. Thus, while the high contrast region 601 covers the adjacent counter region 602, the high recognition region 502 does not completely cover the adjacent embedded region 503, as shown in fig. 12 and 13.

In order to realize the anti-counterfeiting of fingerprint identification, the device also provides an anti-counterfeiting scheme in some embodiments, so as to avoid the attack on a prosthetic limb such as a printed fingerprint image, a imitated fingerprint film or a fingerprint film tool caused by collecting only a two-dimensional plane fingerprint image.

As shown in fig. 11, the at least two types of excitation light sources may further include a third type of excitation light source 703 for emitting detection light in a third wavelength band, where the third wavelength band does not overlap with the first wavelength band and the second wavelength band. For example, the first, second and third bands are red, green and blue bands, respectively. The purpose of the design is to adopt the light of different wave bands (colors) to identify different angles of the detection light, so that the acquisition of signal light of three angles is realized, and a three-dimensional fingerprint image is obtained. Accordingly, to receive and sense the signal light of the third wavelength band, the at least two different filter layers further include a third type of filter layer 903 for allowing the signal light of the third wavelength band to pass therethrough and filtering the signal light of other wavelength bands.

Similarly, when the excitation light sources include three types, the high recognition areas 502 formed on the cover layer 6 by the adjacent three types overlap each other two by two, and there is a region where the three overlap at the same time. To eliminate the effect of poor imaging quality of the respective counter regions 602, the three counter regions 602 may be formed in regions where the three overlap together.

The sub-pixel units under the same type of filter layer receive signal light in the same wavelength band, and the signal light in the same wavelength band is formed by reflecting detection light with the same wavelength Duan Da and the same incidence angle through the fingers of the user. Since the user's finger includes the texture fluctuation of ridges and valleys, the direction of the signal light formed by the detection light of different angles after being reflected by the user's finger becomes disordered. The signal light with unordered reflection directions can only be identified through different types of photosensitive pixel points 501, so that all sub-pixel units under the same type of filter layer can sense the intensity of the signal light with the wave band to form a graph unit, and the light detection array 5 comprises at least three graph units. In a preferred embodiment, the drawing units are three, respectively a red drawing unit, a green drawing unit and a blue drawing unit.

As shown in fig. 14, the fingerprint identification flow in the embodiment of the invention is as follows:

it is detected whether there is a touch operation on the cover layer 6. Specific detection scheme as described above, the touch display 8 of the electronic device 100 of the present apparatus can detect whether there is any operation of touching, pressing, approaching, etc. the object to be identified on the cover layer 6.

When it is detected that the object to be identified is in contact with the cover layer 6, at least two types of excitation light sources are controlled to operate to emit detection light to the object to be identified, the detection light emitted by each excitation light source correspondingly illuminates a high-contrast area 601 in a circular ring shape on the cover layer 6, and the signal light reflected by the object to be identified reaches the corresponding sub-pixel unit after passing through the filter layer. In some implementations, the device may be used for fingerprint recognition only, and the point light source array may include only two types of excitation light sources, and the two types of excitation light sources emit two types of monochromatic light at the same time.

The sub-pixel units in the photosensitive area sense the intensity of the signal light and output image fragments with different colors. Two different monochromatic lights illuminate different locations of the overlay 6, thereby capturing fingerprint images of different colors of the two areas.

Based on the plurality of image segments, a full fingerprint image is synthesized in a color sequence. Specifically, as shown in fig. 5, there is a proportional enlargement relationship between the high contrast area 601 and the corresponding high recognition area 502. In the case of optical path determination, that is, in the case of optical path distance determination between the signal light propagating from the high-contrast region 601 to the corresponding high-recognition region 502, the magnification ratio is also determined. Wherein the optical path is mainly dependent on the distance between the cover layer 6 and the light detection array 5. Knowing the spatial location of each high contrast region 601, the image segments acquired by each sub-pixel unit, i.e., the partial fingerprint images, can be scaled according to the above-described magnification and stitched together into a full fingerprint image. The light intensity information received by the photosensitive pixel 501 may be scaled to obtain a partial fingerprint image, and then spliced into a full fingerprint image.

As shown in fig. 13, in the high recognition region 502 of the solid line, the photosensitive information of the P0, P1, P2, P3 photosensitive pixels 501 are different, and the position information of the excitation light source is determined using the photosensitive information of the P0, P1 photosensitive pixels 501; determining the scaling of the partial fingerprint image by using the photosensitive information of the P2 and P3 photosensitive pixel points 501; the order of splicing the partial fingerprint images in the two high recognition areas 502 is determined using the photosensitive information of the overlapping area of the high recognition area 502 of the solid line and the high recognition area 502 of the broken line.

The above-mentioned decision rule may be implemented according to any suitable known technique, and will not be described here in detail.

And then, matching the synthesized full fingerprint image with a pre-stored fingerprint image to judge whether the object to be identified is the real finger of the user. If the matching is consistent, judging that the object to be identified is the real finger of the user, and completing identification. Otherwise, the identification fails because the identification is not the real finger of the user.

In light of the above description, the light detection array 5 comprises at least three picture elements for anti-counterfeiting purposes. As shown in fig. 15, in this embodiment, the steps before outputting the image segments are the same as those of the above-described embodiment. In the step of outputting image segments, each of the graphic units receives signal light from the same wavelength band and outputs a group of image segments of a corresponding color. And constructing a three-dimensional stereoscopic image of the object to be identified according to the image fragments output by the at least three image units.

Each image unit performs interpolation (e.g., bayer interpolation) operation based on the received signal light from the same band and the signal light of other bands around the same band, so as to obtain an original image. For example, as shown in fig. 13, the photosensitive pixel 501 located at the middle and corresponding to the G (green) filter layer receives G signal light, two photosensitive pixel 501 on the left and right receive B (blue) signal light, and two photosensitive pixel 501 on the upper and lower receive R (red) signal light. The light detection array 5 performs interpolation operation based on the G signal light received by the middle photosensitive pixel 501, the B signal light received by the left and right photosensitive pixel 501, and the R signal light received by the upper and lower photosensitive pixel 501, to obtain an original image output by the photosensitive pixel 501 receiving the G signal light.

As shown in fig. 16, at least three of the drawing units output images, respectively, corresponding to fingerprints illuminated from different angles. Then, a color fingerprint image can be obtained from the three sets of original images output by the at least three image units. According to a light intensity gradient mapping table stored in a preset fingerprint information base, gradient information is solved by utilizing the color fingerprint image, so that depth information of the fingerprint, namely ridge and valley texture fluctuation of the fingerprint is restored. Thus, three-dimensional construction of the fingerprint image of the object to be identified is completed, and then anti-counterfeiting identification is carried out by utilizing the three-dimensional fingerprint image. And then, matching the constructed three-dimensional image with a pre-stored fingerprint image to judge whether the object to be identified is the real finger of the user.

Further, according to the original images output by at least three image units, the quality of the three-dimensional stereo image of the fingerprint can be improved through different phase compensation (such as displacement) and weighting (compensation of sensitivity difference of illumination of different wave bands), and skin color judgment can be performed. Therefore, the skin color information of the finger is added into fingerprint identification, so that attacks similar to a fingerprint mold manufactured by artificial materials such as silica gel, white glue and the like, 3D printed artificial limbs and the like are avoided, and the anti-counterfeiting effect of the fingerprint identification is improved.

The thinned under-screen optical fingerprint identification device provided by the embodiment of the invention utilizes a plurality of light beams with different wavebands and different incident angles to reconstruct the three-dimensional characteristics of the user fingerprint, so that the anti-counterfeiting effect of fingerprint identification is improved.

Because the filter layer is disposed in a non-selective blind-paste manner, each photosensitive pixel 501 includes at least two types of sub-pixel units. Therefore, each photosensitive pixel 501 can receive signal light of a different color. In order to distinguish the signal light of the non-color, output the photosensitive signal or image fragment of the corresponding color, the corresponding algorithm setting needs to be performed on the image processing and the drawing of the sub-pixel unit.

Specifically, the sub-pixel units covered by the high recognition area 502 and the embedded area 503 each output at least two different photosensitive signals. In this way, the wavelength band or color type of the photosensitive signal output from the sub-pixel unit covered under the high recognition area 502 and the embedded area 503 is the same, and the difference is that the intensity of the photosensitive signal and the amount of the fingerprint signal output from the two are different.

The image data processing unit may identify and reject the photosensitive signals input by the sub-pixel units covered under the embedded region 503 based on a preset rule while only retaining the photosensitive signals input by the sub-pixel units covered by the high identification region 502. As described above, the intensity of the photosensitive signal and the amount of the fingerprint signal output from the high recognition area 502 and the embedded area 503 to the image data processing unit are different, specifically: the intensity of the photosensitive signal output from the high recognition area 502 to the image data processing unit is lower than that of the photosensitive signal output from the embedded area 503 to the image data processing unit (because the embedded area 503 is illuminated by the signal light reflected from the probe light on the reversed area 602 and the reversed area 602 is closer to the excitation light source than the high contrast area 601), and the amount of the fingerprint signal and the contrast in the photosensitive signal output from the high recognition area 502 to the image data processing unit are larger than those in the photosensitive signal output from the embedded area 503 to the image data processing unit, and the contrast is better.

The image data processing unit may store a noise standby board in advance, after receiving the photosensitive signal input by the sub-pixel unit, the image data processing unit may compare the photosensitive signal input by the sub-pixel unit with the preset noise standby board, and subtract the photosensitive signal input by the sub-pixel unit corresponding to the matching photosensitive signal, that is, the embedded area 503, and only retain the photosensitive signal input by the sub-pixel unit under the high recognition area 502.

Since this embodiment uses an algorithm to subtract noise from the photosensitive signal output by the embedded region 503, the channel formed by the high identification region 502 and all the sub-pixel units covered under the embedded region 503 is turned on. After receiving the photosensitive signals output by the high recognition area 502 and the embedded area 503, the image data processing unit recognizes and rejects the photosensitive signals input by the embedded area 503 based on the above-mentioned preset rule, and only retains the photosensitive signals input by the high recognition area 502.

It should be noted that, in the description of the present invention, the terms "first," "second," and the like are used for descriptive purposes only and to distinguish between similar objects, and there is no order of preference between them, nor should they be construed as indicating or implying relative importance. Furthermore, in the description of the present invention, unless otherwise indicated, the meaning of "a plurality" is two or more.

Any numerical value recited herein includes all values of the lower and upper values that increment by one unit from the lower value to the upper value, as long as there is a spacing of at least two units between any lower value and any higher value. For example, if it is stated that the number of components or the value of a process variable (e.g., temperature, pressure, time, etc.) is from 1 to 90, preferably from 21 to 80, more preferably from 30 to 70, then the purpose is to explicitly list such values as 15 to 85, 22 to 68, 43 to 51, 30 to 32, etc. in this specification as well. For values less than 1, one unit is suitably considered to be 0.0001, 0.001, 0.01, 0.1. These are merely examples that are intended to be explicitly recited in this description, and all possible combinations of values recited between the lowest value and the highest value are believed to be explicitly stated in the description in a similar manner.

Unless otherwise indicated, all ranges include endpoints and all numbers between endpoints. "about" or "approximately" as used with a range is applicable to both endpoints of the range. Thus, "about 20 to 30" is intended to cover "about 20 to about 30," including at least the indicated endpoints.

The foregoing is merely a few embodiments of the present invention and those skilled in the art, based on the disclosure herein, may make numerous changes and modifications to the embodiments of the present invention without departing from the spirit and scope of the invention.

Claims

1. A slim underscreen optical fingerprint recognition device, comprising:

2. The thinned under-screen optical fingerprint recognition device of claim 1, wherein the cover layer and the array of point light sources are disposed on a self-luminous display screen configured by an electronic device to which the thinned under-screen optical fingerprint recognition device is applied; the self-luminous display screen comprises a luminous layer, the luminous layer comprises a plurality of self-luminous pixel units, and the excitation light source consists of one or a plurality of luminous pixel units.

3. The slim type under screen optical fingerprint recognition device of claim 1, wherein the excitation light source is an additionally provided light emitting device.

4. The thinned underscreen optical fingerprint identification device of claim 1, wherein the number of each type of excitation light source is plural, at least two types of excitation light sources are alternately arranged, and the wavelength bands of detection light emitted by adjacent two excitation light sources are different.

5. The thinned under-screen optical fingerprint recognition device of claim 1, wherein each high contrast region covers an inner circular region of an adjacent high contrast region; the inner circular area is illuminated by probe light having an incident angle less than the first critical angle.

6. The slim underscreen optical fingerprint identification device of claim 1, wherein said at least two types of excitation light sources are configured to emit light simultaneously.

7. The slim underscreen optical fingerprint identification device of claim 1, wherein said at least two types of excitation light sources include: the first-type excitation light source and the second-type excitation light source are respectively used for emitting detection light of a first wave band and a second wave band; the at least two different filter layers include: the first type filter layer and the second type filter layer are respectively used for allowing the signal light of the first wave band and the second wave band to pass through.

8. The thinned under-screen optical fingerprint identification device of claim 7, wherein the at least two types of excitation light sources further comprise a third type of excitation light source for emitting detection light of a third wavelength band, the third wavelength band not overlapping the first and second wavelength bands; the at least two different filter layers further include a third type of filter layer for allowing signal light of a third wavelength band to pass therethrough.

9. The thinned underscreen optical fingerprint identification device of claim 1, wherein each photosensitive pixel comprises three types of sub-pixel units, each type of sub-pixel unit receiving and sensing signal light in three different wavebands, respectively, at least one of each type of sub-pixel units.

10. The thinned under-screen optical fingerprint recognition device of claim 1, wherein the signal light formed by the reflection of the detection light to the high contrast area by the object to be recognized illuminates a ring-shaped high recognition area on the photosensitive pixel array, the inner circular boundary of the high recognition area corresponding to the signal light reflected by the detection light of the first critical angle and the outer circular boundary corresponding to the signal light reflected by the detection light of the second critical angle.

11. The thinned under-screen optical fingerprint identification device of claim 10, wherein the array of photosensitive pixels is in signal connection with an image data processing unit, each sub-pixel unit comprising a channel; the image data processing unit receives the photosensitive signals input by the high identification area and the sub-pixel units covered by the embedded area;

the image data processing unit identifies and deducts the photosensitive signals input by the sub-pixel units covered by the embedded area based on a preset rule, and only retains the photosensitive signals input by the sub-pixel units covered by the high identification area.

12. A method of fingerprint identification using the slim underscreen optical fingerprint identification device of claim 1, the method comprising:

when the contact of the object to be identified on the cover layer is detected, controlling the at least two types of excitation light sources to emit detection light to the object to be identified, wherein the detection light emitted by each excitation light source correspondingly illuminates a circular high-contrast area on the cover layer, and the signal light reflected by the object to be identified reaches the corresponding sub-pixel units after passing through the filter layer and forms a circular high-identification area on the light detection array;

13. The method of claim 12, wherein the same type of sub-pixel units receive and sense signal light of the same wavelength band to form a picture unit, and the light detection array comprises at least three picture units;

in the step of outputting image segments, each of the image units receives signal light from the same wave band and outputs a group of image segments with corresponding colors;

and constructing a three-dimensional stereoscopic image of the object to be identified according to the image fragments output by at least three image units.

14. The method of claim 13, wherein after the step of constructing a three-dimensional stereoscopic image of the object to be identified, the method further comprises:

and matching the constructed three-dimensional image with a pre-stored fingerprint image to judge whether the object to be identified is a real finger of a user.

15. The method of claim 14, wherein constructing a three-dimensional stereoscopic image of the object to be identified comprises:

obtaining a color fingerprint image according to the original images output by at least three image units;

according to a light intensity gradient mapping table stored in a preset fingerprint information base, solving gradient information by utilizing the color fingerprint image, and restoring depth information of an object to be identified;

and obtaining a three-dimensional image of the object to be identified according to the restored depth information of the object to be identified.

16. The method according to any one of claims 12 to 15, wherein after the step of outputting the original image by the map unit, the method further comprises:

performing phase compensation and weighting calculation on the original image to obtain the skin color of the object to be identified;

the step of matching the fingerprint images comprises the following steps: and matching the skin color of the obtained object to be identified with the skin color of the pre-stored fingerprint image to judge whether the object to be identified is the real finger of the user.

17. The method according to claim 16, wherein in the step of fingerprint image matching, at least one of the synthesized full fingerprint image, three-dimensional stereoscopic image or skin tone information is transmitted to a processor, and is matched with the fingerprint image, three-dimensional stereoscopic image or skin tone information of the user stored in the processor in advance, and the processor determines whether the object to be identified is a real finger of the user according to the matching result;

The processor is arranged in the electronic equipment for applying or configuring the thinned under-screen optical fingerprint identification device.

18. A method as claimed in claim 12, wherein the fingerprint is identified by means of a thinned under-screen optical fingerprint identification device as claimed in claim 10, and wherein the step of outputting the image segments:

the sub-pixel units covered by the embedded area defined by the inner circle boundary of the high identification area output photosensitive signals;

based on a preset rule, recognizing and eliminating the photosensitive signals input by the sub-pixel units covered by the embedded area, and only retaining the photosensitive signals input by the sub-pixel units covered by the high recognition area.