CN111582131A

CN111582131A - Thin optical fingerprint identification device under screen and fingerprint identification method

Info

Publication number: CN111582131A
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: 2020-08-25
Anticipated expiration: 2040-04-30
Also published as: CN111582131B

Abstract

The invention provides a thin optical fingerprint identification device under a screen and a fingerprint identification method, wherein the device comprises a light detection array with a photosensitive area, the 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 spot light source array comprises at least two types of excitation light sources, wherein detection light emitted to an object to be identified illuminates a high-contrast area on a covering layer, and the inner circle boundary and the outer circle boundary of the high-contrast area respectively correspond to the detection light of a first critical angle and the detection light of a 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 optical fingerprint identification device under the screen can also realize the collection of fingerprint signals without arranging a lens or a micro lens, has thinner thickness and is beneficial to the light and thin design of electronic equipment.

Description

Thin optical fingerprint identification device under screen and fingerprint identification method

Technical Field

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

Background

The off-screen optical fingerprint identification can be applied to electronic equipment including but not limited to a smart phone or other electronic equipment with a man-machine interaction function. 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 realizing the optical fingerprint recognition under the screen can be a self-luminous display screen 1 of the electronic device, such as an OLED screen. The display screen 1 emits detection light to a finger of a user, the detection light is reflected by the finger of the user to form signal light carrying user fingerprint information, and the signal light is transmitted 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, the signal light is converged onto the fingerprint chip 3 through a lens 2 disposed between the display screen 1 and the fingerprint chip 3. Alternatively, as shown in fig. 2, in another known embodiment, the signal light is finally focused on the fingerprint chip 3 through the micro lens 4 disposed on the fingerprint chip 3.

The fingerprint module under the screen of above-mentioned two kinds of known embodiments needs lens module or microlens structure between fingerprint chip and display screen, leads to the structure of fingerprint identification module more complicated, and processing cost is higher. In addition, because need lens module or microlens structure between fingerprint chip and display screen, lead to the fingerprint identification module thicker, be unfavorable for electronic equipment's frivolousization.

Disclosure of Invention

Based on the foregoing defects in the prior art, embodiments of the present invention provide a thin optical fingerprint identification device and fingerprint identification method under a screen, which do not need to arrange a lens module or a microlens structure on a fingerprint chip and a display screen support, can also collect fingerprint signals, are thin, and are beneficial to the light and thin design of electronic devices.

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

A thinned underscreen optical fingerprint identification 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 being contacted by an object to be identified;

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

when the optical fingerprint identification device under the thin screen detects that an object to be identified is contacted with the covering layer, the detection light emitted by each excitation light source to the object to be identified correspondingly illuminates a circular high-contrast area on the covering layer, the inner circle boundary of the high-contrast area corresponds to the detection light at a first critical angle, and the outer circle boundary corresponds to the detection light at a second critical angle; the signal light reflected by the object to be identified 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 an angle of total reflection of light rays at an interface of the cap layer and the gap, and the second critical angle corresponds to an angle of total reflection of light rays at an interface of the cap layer and the ridge.

A method for fingerprint identification by using the thinned optical fingerprint identification device under the screen in the embodiment, the method comprising:

when the contact of an object to be identified on the covering layer is detected, the 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 circular high-contrast area on the covering layer, and the detection light reaches the corresponding sub-pixel unit after being reflected by the object to be identified through the filter layer;

the sub-pixel units sense the intensity of the signal light and output image segments 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 the real finger of the user.

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

In addition, the optical fingerprint identification device and the fingerprint identification method under the thin screen of the embodiment of the invention can collect color fingerprint images by utilizing light with a plurality of different wave bands and different incidence angles, and restore three-dimensional or three-dimensional fingerprint characteristics, so that the anti-counterfeiting effect is better.

Specific embodiments of the present invention are disclosed in detail with reference to the following description and 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 so limited in scope.

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, the proportional sizes, and the like of the respective members in the drawings are merely schematic for facilitating the understanding of the present invention, and do not specifically limit the shapes, the proportional sizes, and the like of the respective members of the present invention. Those skilled in the art, having the benefit of the teachings of this invention, may choose from the various possible shapes and proportional sizes to implement the invention as a matter of case. In the drawings:

FIG. 1 is a diagram of a fingerprint recognition structure in one embodiment of the prior art;

FIG. 2 is a diagram of a fingerprint identification structure in another embodiment known in the art;

FIG. 3 is a profile view of a thinned, underscreen optical fingerprint recognition device in one non-limiting embodiment of the invention;

FIG. 4 is a block diagram of a thinned underscreen optical fingerprint recognition device in one non-limiting embodiment of the present invention;

FIG. 5 is an optical diagram of a thinned underscreen optical fingerprint recognition device in one non-limiting embodiment of the present invention;

FIG. 6 is a schematic diagram of a point light source array formed on a light-emitting layer of a self-luminous display panel in a thin optical fingerprint identification device under the panel in a non-limiting embodiment of the invention;

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

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

FIG. 9 is an actual acquired fingerprint image;

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

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

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

FIG. 13 is a diagram illustrating a photodetector array and an array of light-sensitive pixels included in the photodetector array and filter layers disposed on the array of light-sensitive pixels in one non-limiting embodiment;

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

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

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

Detailed Description

In order to make those skilled in the art better understand the technical solution of the present invention, the technical solution in the embodiment of the present invention will be clearly and completely described below with reference to the drawings in the embodiment of the present invention, and it is obvious that the described embodiment is only a part of the embodiment of the present invention, and not all embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, shall fall within the scope of protection of the present 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 as used herein are for illustrative purposes only and do not denote a single embodiment.

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

In view of the fact that in the prior art embodiments shown in fig. 1 and 2, the entire thickness of the fingerprint identification structure is relatively thick due to the lens module or the micro-lens structure being required to be disposed between the fingerprint chip and the display screen, which is not favorable for the light and thin structure design of the electronic device, the embodiment of the present invention provides a thin optical fingerprint identification device under the screen (hereinafter, referred to as the present device for convenience of description) shown in fig. 3. The device enables the fingerprint pattern to 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 eliminated, so that the thickness of the fingerprint identification device is thinner and lighter, and the thinning design of electronic equipment is facilitated. Moreover, the structure of the fingerprint identification device is simplified, and the manufacturing cost is greatly reduced.

As shown in fig. 4, the apparatus may be used 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, etc. The following description will mainly describe a scenario in which the apparatus is applied to a smartphone, 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 positioned over the light detection array 5, and an array of point light sources positioned 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 sequentially disposed from top to bottom.

The light detecting array 5 may be part of a fingerprint chip. The fingerprint chip can include photosensitive area and non-photosensitive area, and photosensitive pixel array is equipped with on the photosensitive area. Therefore, in the present embodiment, the portion of the fingerprint chip on which the photosensitive pixel array is provided may be defined as the light detection array 5. That is, the photosensitive area of the photo-detecting 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 pixels 501, which may be arranged in a rectangular array m × n, for receiving the signal light and sensing the intensity of the signal light.

The light detection array 5 is disposed below the point light source array. Specifically, the electronic device 100 such as a smartphone is provided with a center through which a fingerprint chip is provided below the point light source array, and realizes fixation of the light detection array 5. The photo detector array 5 is used to convert the received optical 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 from the fingerprint chip, can also be integrated in the fingerprint chip, and can be specifically arranged in a non-photosensitive area. The image data processing unit can perform image processing to obtain a fingerprint image and provide the generated fingerprint image to a processor in signal connection with the fingerprint image. The processor can compare and match the generated fingerprint image with a standard fingerprint image 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 records fingerprint image information of the real finger of the user in advance and stores the fingerprint image information in a local information base, namely a processor. When fingerprint identification is carried out, the generated fingerprint image is compared with the standard fingerprint image stored in the information base. And when the comparison result shows that the similarity of the two images reaches a 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. Then, the smartphone completes screen unlocking, permission obtaining, and the like (e.g., payment, login, and the like).

On the contrary, if the comparison result shows that the similarity of the two images is lower than the set threshold, the generated fingerprint image is not matched with the standard fingerprint image, and the current object to be identified is an attack artificial limb such as a printed fingerprint image, a simulated fingerprint film or a fingerprint film. The smart phone continuously maintains the current operation interfaces such as screen locking, permission acquisition failure and the like unchanged.

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

Of course, to enhance the anti-counterfeit property 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 the skin color information of the object to be identified. Correspondingly, the standard image information pre-recorded and stored in the processor further comprises a three-dimensional stereo image or skin color information, and the three-dimensional stereo image or skin color information is 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 enhance the anti-counterfeiting performance of the identification effect.

In this embodiment, the processor may be provided in the electronic device. Therefore, the device generates a fingerprint image and provides the generated fingerprint image to a processor of the electronic equipment for identification. That is, the device is responsible for collecting and generating a fingerprint image, and the processor identifies according to the generated fingerprint image.

With continued reference to fig. 4, the cover layer 6 has a contact area for an object to be identified (e.g., a user's finger, a printed fingerprint image, a simulated fingerprint film, etc.) to contact or press. Since the detection light emitted by the point light source array needs to irradiate the object to be identified pressed on the contact area, the arrangement of the covering layer 6 does not affect the light path in general and is made of a light-transmitting material in general. But not limited to, in other embodiments, the cover layer 6 is not necessarily limited to a material that is completely light transmissive due to the particular design.

The cover layer 6 is disposed above the array of point light sources, and may be a protective cover plate for protecting the array of point light sources, including a cover glass or a sapphire cover plate. 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. Therefore, in the embodiment of the present invention, the so-called object to be recognized contacts or presses the cover layer 6, and in fact, the object to be recognized may be directly pressed on the cover layer 6 or pressed on the protective layer.

As shown in fig. 6, the point light source array includes at least two types of excitation light sources for emitting probe light of at least two different wavelength bands to the object to be identified contacting the cover layer 6. Since the wavelength band of the light corresponds to the color of the light, the wavelength band of the probe light is different from the color of the probe light.

Further, in order to enable the signal light formed by the detection light emitted by one type of excitation light source after being reflected by the object to be identified to be received by the specific sub-pixel unit only through the corresponding filter layer, in some preferred embodiments, the wavelength bands of the detection light emitted by any two types of excitation light sources do not overlap. For example, in some non-limiting scenarios, the detection light emitted by the first excitation light source 701 is red light (wavelength band range of 610-. Because the filter layer can only effectively filter the light rays in a specific wave band, different types of excitation light sources are adopted to emit visible detection light which are separated from each other on a frequency spectrum, and the crosstalk of 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 point light source array may be disposed on a self-luminous display screen configured with an electronic device 100 (e.g., a smart phone) to which the apparatus is applied, such as an OLED screen or an LED screen. Or, in other words, a partial region of the self-luminous display screen provided in the electronic apparatus 100 itself using or configuring the present device constitutes the cover layer 6 and the point light source array. The self-emissive display screen may comprise a light-emitting layer 7, such as an OLED light-emitting layer or an LED light-emitting layer. The partial area of the luminescent layer 7 corresponding to the cover layer 6 constitutes the area where the array of point light sources is arranged.

As shown in 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 cells 704 are caused to emit light of a corresponding color by modulating the RGB values of the RGB light-emitting pixel array within each light-emitting pixel cell 704. For example, if all R (red) pixels in the pixel unit 704 are operated, and G (green) and B (blue) pixels are not operated, the pixel unit 704 emits monochromatic red light. Similarly, if all G pixels in pixel element 704 are operating and the R, B pixels are not operating, then pixel element 704 emits a single color of green light. If all of the B pixels in the light-emitting pixel unit 704 are operated and the R, G pixels are not operated, the light-emitting pixel unit 704 emits monochromatic blue light. Alternatively, if all R, G, B pixels in the light-emitting pixel unit 704 are operated and the RGB values are all 255, the light-emitting pixel unit 704 emits white light with multiple colors.

In one 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 collectively constitute one excitation light source. At this time, the excitation light source is a cluster of adjacent light-emitting pixel units 704.

According to various embodiments of the present invention, the probe light emitted by the excitation light source may be a monochromatic light, such as red, blue, or green light. Then the RGB pixel array in one or more of the pixel cells 704 included in the excitation light source has target light-emitting pixels that are operational and non-target light-emitting pixels that are not. For example, when one of the excitation light sources is to emit red probe light, the target light-emitting pixel in the RGB light-emitting pixel array is an R pixel, and the G, B pixel is a non-target light-emitting pixel.

Similarly, if another excitation light source is to emit green probe light, the target light-emitting 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 light-emitting pixel points. Or, if another excitation light source is to emit blue detection light, the target light-emitting pixel points in the RGB light-emitting pixel array are B pixel points, and the R pixel points and the G pixel points are non-target light-emitting 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, the excitation light sources in the same column or row, two adjacent excitation light sources do not belong to the same class. That is, in this embodiment, not all of the light-emitting pixel units 704 included in the light-emitting layer 7 of the self-luminous display panel are used as excitation light sources, but a part of all of the light-emitting pixel units 704 is selected as an excitation light source, and the other light-emitting pixel units 704 that are not used as excitation light sources do not emit light (are turned off) when the present apparatus is in an operating state, and emit light in a resting state. Also, when normal display is required, all the light-emitting pixel units (including the light-emitting pixel units serving as the excitation light source and the light-emitting pixel units not serving as the excitation light source) preferably emit white light for display.

The working state may be a state when fingerprint recognition is performed. Accordingly, the rest state is a state when fingerprint recognition is not required to be performed or not performed. For example, the display screen 8 is a touch display screen, which can switch the operation mode of the apparatus from the current mode to the operation state based on the approaching, contacting, pressing, or other actions of the object to be recognized or the internal program instructions of the electronic device 100. After finishing fingerprint identification, the working mode of the device is switched to a resting state.

For example, in a scene that a screen of a smartphone needs to be unlocked, a current black screen state of the smartphone is a resting state. When the display screen 8 detects an approach, contact, pressing, or the like of an 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), and the other light-emitting pixel units 704 not serving as the excitation light sources do not emit light, thereby illuminating the cover layer 6. When the object to be identified pressed on the covering layer 6 is the real finger of the user, the fingerprint identification is successful, and the screen unlocking is completed. Subsequently, the other light-emitting pixel units 704 which do not serve as the excitation light source recover light emission (preferably white light) for light intensity supplement, and the light-emitting pixel units 704 which serve as the excitation light source also recover light emission of white light, thereby realizing uniform display of the picture.

For another example, in a scene that the smart phone performs fingerprint payment, the current awake state of the smart phone is the resting state. At this time, the light-emitting layer 7 includes all the light-emitting pixel units 704 which emit white light. When the payment interface or payment control pops up, those light-emitting pixel units 704 that do not act as excitation light sources go out or are dimmed, while the light-emitting pixel units 704 that act as excitation light sources continue to operate to emit light (specifically, different types of excitation light sources may emit monochromatic light of different wavelength bands or colors), thereby illuminating the overlay layer 6. When the object to be recognized pressed on the cover layer 6 is the real finger of the user, the fingerprint recognition is successful, and the payment is completed. Subsequently, other light-emitting pixel units 704 not used as the excitation light source recover light (preferably white light), and light-emitting pixel units 704 used as the excitation light source also recover white light to normally display the interface of the mobile phone.

By adopting the above design, when the device is actually applied to the electronic device 100, the following emission of the probe light can be realized without arranging an additional light source, so that the volume of the device can be reduced, and the light and thin design of the electronic device 100 is facilitated.

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

Certainly, the point light source array is not limited to the above embodiments, and in other possible embodiments, the point light source array may include an additional light emitting device, and the emitted detection light may be visible light or invisible light, such as an LED (implementing visible light), an infrared light source, an ultraviolet light source, a far infrared light source (implementing invisible light), and the like, which is not limited in this embodiment. In the embodiment where the point light source array includes the excitation light source composed of the additionally provided light emitting device, the electronic apparatus 100 using the present device is configured with the display screen 8 only for image display and human-computer interaction, and not for emitting the probe light.

According to various embodiments of the present invention, the photosensitive pixel 501 in a rectangular array m × n includes at least two types of sub-pixel units, and at least two different filter layers are correspondingly disposed on or above the at least two types of sub-pixel units. Alternatively, it can also be said that, by disposing different kinds of filter layers in different position areas of the entire photosensitive pixel array, the pixel units included in the photosensitive pixel 501 are divided into different kinds of sub-pixel units. For example, a red (R) filter layer is disposed on some regions of the photosensitive pixel 501, and a red sub-pixel unit is formed under the region, and only red signal light is sensed and received. Alternatively, a green (G) filter layer is disposed on another region of the photosensitive pixel 501, and a green sub-pixel unit is formed under the region, and only green signal light is sensed and received. Or, a blue (B) filter layer is disposed on another region of the photosensitive pixel 501, so that a blue sub-pixel unit is formed under the region, and only the blue signal light is sensed and received.

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

According to the principle of total reflection, when light enters the optically thinner medium from the optically denser medium and the incident angle is increased to a certain critical angle, the refraction angle reaches 90 degrees, the refraction light disappears, and all incident light is reflected back to the optically denser medium without being transmitted into the optically thinner medium. Wherein 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 the finger of the user as an example, when the finger of the user presses on the cover layer 6, a gap (generally, an air gap) is formed between the fingerprint valley and the cover layer 6, and the fingerprint ridge is in contact with the cover layer 6. It is often difficult for the user's fingers to achieve strict dryness. Therefore, between the fingerprint ridges and the cover layer 6, there is usually a sweat stain. With respect to the cover layer 6 (typically of glass), the air gap and the skin tissue or sweat of the human body are optically thinner media. Whereas the skin tissue or sweat stain of the human body is an optically dense medium with respect to the air gap.

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

where n2 is the refractive index of the optically thinner medium, which corresponds to the refractive index of the cover layer 6 in the present embodiment. n1 is the refractive index of the optically dense medium, corresponding to the refractive index of the skin tissue of the finger or air gap in this embodiment; when there is sweat stain on the finger, it corresponds to the refractive index of sweat stain (liquid).

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

Specifically, referring to fig. 5, the total reflection angle of the light at the interface of the cover layer 6 and the air gap of the fingerprint valley is denoted as a first critical angle θ 1, 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 θ 2. From the above analysis, the first critical angle θ 1 is smaller than the second critical angle θ 2.

When the incident angle of the probe light is smaller than the first critical angle θ 1, the incident light is partially reflected + partially refracted at both the fingerprint valley and the fingerprint ridge, and most of the refracted light reaches the surface of the finger. The light refracted at the fingerprint valley is reflected by the skin of the fingerprint valley, and is reflected twice, three times or more at the interface of the air gap and the covering layer 6, so that more loss is generated. Therefore, the fingerprint image obtained in this case exhibits an effect of dark valleys and bright ridges, and has poor contrast.

Simply, it is just above the excitation light source that no better fingerprint image can be obtained, such as the central bright spot or bright patch illustrated in fig. 9.

As shown in fig. 7, the optical path diagram is shown when the incident angle of the probe light emitted from the excitation light source is greater than the first critical angle θ 1 but less than the second critical angle θ 2. At this time, the probe light is totally reflected at the fingerprint valleys, but partially reflected + partially refracted at the fingerprint ridges. At this time, the obtained fingerprint image has the effect of bright valleys and dark ridges, and the contrast of the bright and dark ridges is optimal. Therefore, the area of the cover layer 6 illuminated when the probe light satisfies such an incident angle is referred to as a high contrast area 601.

As shown in fig. 10, the probe light emitted from each excitation light source (701, 702) illuminates a high contrast area 601 on the cover layer 6. The high contrast region 601 is annular and includes two concentric circles with the excitation light sources (701, 702) as the center, and the annular region defined between the two concentric circles is the high contrast region 601. The inner circle boundary corresponds to the detection light of the first critical angle theta 1, and the outer circle boundary corresponds to the detection light of the second critical angle theta 2.

As shown in fig. 8, the 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 θ 2. Then, the probe light is totally reflected at both the fingerprint ridge and the fingerprint valley, so that the fingerprint ridge and the fingerprint valley exhibit no or small difference. Therefore, a fingerprint image is not obtained at a distance from the excitation light source, as illustrated by the edge blur area in fig. 9.

In the embodiment where the excitation light source is formed by the light-emitting pixel unit 704 in the display screen 8 of the electronic device 100 using 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. The excitation light source then emits a surface light when in operation. That is, the angle of the light emitted by the excitation light source is non-selective or arbitrary. The detection light not only includes useless light with an incident angle smaller than the first critical angle theta 1 and larger than the second critical angle theta 2, but also includes useful detection light with an incident angle between the first critical angle theta 1 and the second critical angle theta 2. However, as described above, the light having the incident angle greater than the second critical angle θ 2 cannot obtain the fingerprint image and thus can be ignored. And the area illuminated by the light with the incident angle smaller than the first critical angle θ 1 is the inner circle area of the high contrast area 601. As can be seen from the above description, the ridge-valley characteristics of the fingerprint image obtained from the inner circle region are exactly opposite to the ridge-valley characteristics of the fingerprint image obtained from the high-contrast region 601. Therefore, for convenience of explanation, the inner circle region of the high contrast region 601 is named as the inversion region 602.

As described above, in the inversion region 602, a superior fingerprint image cannot be obtained by only depending on the corresponding excitation light source. Thus, the region can be supplemented with adjacent excitation light sources. Specifically, as shown in fig. 10, the high-contrast area 601 covers the inner circle area of the adjacent high-contrast area 601. Thus, the inverted area 602 is covered by the adjacent high-contrast area 601, so that part of the position of the object to be identified in the inverted area 602 is irradiated by the adjacent high-contrast area 601, thereby acquiring the fingerprint image in the inverted area 602, ensuring that the fingerprint image can be acquired with higher quality everywhere, and further ensuring that the quality of the finally acquired fingerprint image is better.

When detecting that the object to be identified on the covering layer 6 is contacted, the device is switched to the working state, 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 covering layer 6. When the incident angle of the probe light is between the first critical angle θ 1 and the second critical angle θ 2, the object to be identified located in the high contrast area 601 reflects the probe light downward to form a signal light carrying fingerprint information. After the signal light propagates downwards and is filtered by the filter layer, the remaining signal light reaches the corresponding sub-pixel unit. Therefore, the same kind of sub-pixel units receive signal light of the same wave band, and different kinds of sub-pixel units receive signal light of different wave bands, so that the fingerprint image is collected.

As can be seen from fig. 5, when the positions of the excitation light sources (701, 702) included in the point light source array are not changed, the thickness of the cover layer 6 may affect the area size of the high-contrast region. Specifically, when the position of the excitation light source (701, 702) is not changed, the thickness of the cover layer 6 increases, and the areas of the high-contrast regions 601 illuminated on the cover layer 6 by the probe light of the first critical angle θ 1 and the second critical angle θ 2 also increase. In addition, the 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. Therefore, in the present embodiment, the high contrast area 601 may cover the adjacent inversion area 602 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 pixel for emitting the detection light and the light-sensing pixel for sensing the light are disposed on the same layer, and are disposed on the light-emitting layer of the display screen. That is, the pixels on the light-emitting layer include light-emitting pixels and light-sensitive pixels, and these light-sensitive pixels can also emit light. When needing fingerprint identification promptly, these sensitization pixel are used for the sensitization, when not needing fingerprint identification and display screen, these sensitization pixel are luminous normally. However, in the conventional embodiment, some specific pixels included in the light emitting layer need to be switched back and forth between the light sensing and light emitting modes, which is difficult to implement and complicated in algorithm and control procedure. Therefore, the cost is high, and the large-area popularization and application in practice are difficult.

In the embodiment of the present invention, the light-emitting pixel points for emitting the detection light and the light-sensing pixel points 501 for sensing the light are arranged in layers, and the two pixel points with different functions are arranged in two layers. Therefore, the functions or the effects 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 the excitation light sources emit detection light in 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 the corresponding angle, when all the excitation light sources emit the detection light in the same wavelength range, the excitation light sources are required to be operated and emitted sequentially, and all the excitation light sources cannot emit light simultaneously. Otherwise, the photosensitive pixel 501 cannot discriminate from which angle the received signal light is reflected, so that the received signal light is mixed up and cannot be imaged. Because the excitation light sources need to emit light in sequence, the fingerprint identification can be completed only by adopting the mode in a long time, 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 efficiency of fingerprint identification, in this embodiment, the excitation light sources are configured into at least two types, where the at least two types of excitation light sources emit detection light in different wavelength bands, and signal light in different wavelength bands (colors) can reach corresponding sub-pixel units by means of corresponding filter layers. Therefore, the detection light of different angles is discriminated by the photosensitive pixel 501 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 light of different wave bands, response speed of fingerprint identification is high, identification efficiency is high, and user experience can be greatly improved.

As shown in fig. 4, 5, 6, 10, in one particular embodiment, the excitation light sources may include two types: the first excitation light source 701 and the second excitation light source 702 are respectively configured to emit detection light of a first wavelength band and a second wavelength band. The filter layer correspondence includes two types: the first-type filter layer 901 and the second-type filter layer 902 are respectively configured to allow signal light in a first wavelength band and signal light in a second wavelength band to pass therethrough, and filter signal light in other wavelength bands.

More specifically, in one illustrative scenario, the first type of excitation light source 701 may be a red (R) excitation light source, and the first wavelength band is the red wavelength band. The second type of excitation light source 702 may be a green (G) excitation light source, the first wavelength band being the green wavelength band. Accordingly, the first filter layer 901 is a red (R) filter layer, and the sub-pixel units thereunder are red pixel units; the second filter 902 is a green (G) filter, and the sub-pixel units thereunder are green pixel units. When fingerprint identification is required, red detection light emitted by the first-type excitation light source 701 is reflected by an object to be identified to form red signal light, which can only be received and sensed by the red pixel unit and cannot reach the green pixel unit. Similarly, the green detection light emitted by the second excitation light source 702 is reflected by the object to be identified to form green signal light, which can only be received and sensed by the green pixel unit, but cannot reach the red pixel unit. Therefore, the plurality of light sources respectively contained in each type of excitation light source are operated to emit light simultaneously, and the signal light can be received and sensed by the corresponding sub-pixel units without the problem of signal light crosstalk.

As shown in fig. 12, the signal light formed by the probe light emitted from the excitation light source reflected by the object to be recognized also illuminates a high-recognition area 502 in the shape of a circular ring on the photosensitive pixel array. As described above, the high identification region 502 is defined by two concentric circles around the excitation light source, and the circular ring-shaped region defined between the two concentric circles is the high identification region 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 manner of the high recognition area 502, the sub-pixel units covered by the high recognition area 502 receive and sense the signal light reflected by the high contrast area 601. Accordingly, the area defined by the inner circular boundary of the high identification area 502 receives and senses the signal light reflected back by the inversion area 602. For convenience of explanation, a region defined by the inner circle boundary of the high recognition region 502 is named an embedded region 503.

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

Referring to fig. 5, the signal light emitted by 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 then 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, although the high contrast area 601 covers the adjacent inversion area 602, the high identification area 502 does not completely cover the adjacent in-line area 503, as shown in fig. 12 and 13.

In order to realize anti-counterfeiting of fingerprint identification and avoid attacking artificial limbs such as printed fingerprint images, imitated fingerprint films or fingerprint film films and the like caused by only acquiring fingerprint images of two-dimensional planes, in some embodiments, the device is further provided with an anti-counterfeiting scheme.

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 probe light of 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 wavelength bands are red, green, and blue wavelength bands, respectively. The purpose of the design is to adopt light with different wave bands (colors) to mark different angles of the detection light, so as to realize the acquisition of signal light with three angles, thereby obtaining a three-dimensional fingerprint image. 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 filter layer 903 for allowing the signal light of the third wavelength band to pass through and filtering the signal light of other wavelength bands.

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

The sub-pixel units under the same type of filter layer receive signal light in the same wave band range, and the signal light in the same wave band is formed by reflection of detection light with approximately equal incident angle and approximately equal wave band through a user finger. Because the user's finger contains the texture fluctuation of ridge and valley, the direction of the signal light that is formed after the detection light of different angles reflects through the user's finger becomes disorderly. These signal lights with disordered reflection directions can only be identified through different types of photosensitive pixel points 501, so that all the sub-pixel units under the same type of filter layer can sense the intensity of the signal light in the wave band to form an image drawing unit, and the light detection array 5 includes at least three image drawing units. In a preferred embodiment, there are three mapping elements, red, green and blue.

As shown in fig. 14, the fingerprint identification process according to the embodiment of the present invention is as follows:

it is detected whether there is a touch operation on the cover layer 6. As described above, the touch display 8 of the electronic device 100 can detect whether an object to be recognized touches, presses, approaches, and the like on the cover layer 6.

When detecting that an object to be identified is indeed contacted on the covering layer 6, controlling at least two types of excitation light sources to operate 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 601 on the covering 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 identification only, and the point light source array may include only two types of excitation light sources, which emit two monochromatic lights simultaneously.

The sub-pixel units in the photosensitive area sense the intensity of the signal light and output image segments of different colors. The two different monochromatic lights illuminate different locations of the overlay 6 so that two areas of differently colored fingerprint images are acquired.

Based on the plurality of image segments, full fingerprint images are synthesized in a color sequence. Specifically, as shown in fig. 5, a certain proportional amplification relationship exists between the high contrast area 601 and the corresponding high identification 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 area 601 to the corresponding high identification area 502, the amplification ratio is also determined. Wherein the optical path length depends mainly on the distance between the cover layer 6 and the light detecting array 5. Knowing the spatial position 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-mentioned magnification ratio and spliced into a full fingerprint image. The light intensity information received by the photosensitive pixel 501 can be scaled to obtain a partial fingerprint image, and then the partial fingerprint image is spliced into a full fingerprint image.

As shown in fig. 13, in the high recognition area 502 of the solid line, the photoreception information of the P0, P1, P2, and P3 photoreception pixels 501 are different from each other, and the position information of the excitation light source is determined using the photoreception information of the P0 and P1 photoreception pixels 501; judging the scaling of the local fingerprint image by using the photosensitive information of the photosensitive pixel points 501 of P2 and P3; the stitching order of the local fingerprint images in the two high identification areas 502 is determined by the light sensing information of the overlapping area of the solid high identification area 502 and the dotted high identification area 502.

The above-mentioned decision rule can be implemented according to any suitable known technique, which is not described herein 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. And if the matching is consistent, judging that the object to be recognized is the real finger of the user, and finishing the recognition. Otherwise, the finger is not the real finger of the user, and the identification fails.

Bearing the above description, the light detection array 5 comprises at least three drawing units for anti-counterfeiting. As shown in fig. 15, in this embodiment, the steps before outputting the image segment are the same as those in the above-described embodiment. In the step of outputting image segments, each graph element receives signal light from the same wavelength band and outputs a set of image segments of corresponding colors. And constructing a three-dimensional stereo image of the object to be recognized according to the image segments output by the at least three image drawing units.

Each graph unit performs interpolation (such as Bayer interpolation) operation based on the signal light received by the graph unit from the same wave band and the signal light of other surrounding wave bands, and thus an original image can be obtained. For example, as shown in fig. 13, the light sensing pixel 501 located at the center and corresponding to the G (green) filter layer receives the G signal light, the two light sensing pixels 501 on the left and right receive the B (blue) signal light, and the two light sensing pixels 501 on the top and bottom receive the 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 pixels 501, and the R signal light received by the upper and lower photosensitive pixels 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 graph elements each output an image corresponding to a fingerprint illuminated from a different angle. Then, a color fingerprint image can be obtained according to the three groups of original images output by at least three chart 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 the depth information of the fingerprint, namely the fluctuation of the ridge and valley textures of the fingerprint, is restored. Thus, the three-dimensional construction of the fingerprint image of the object to be identified is completed, and then the three-dimensional fingerprint image is utilized for anti-counterfeiting identification. 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, different phase compensation (such as displacement) and weighting (compensation of sensitivity difference of illumination of different wave bands) can be carried out, the quality of the three-dimensional stereo image of the fingerprint can be improved, and skin color judgment can be carried out. Therefore, the skin color information of the finger is added into the fingerprint identification, the attacks similar to the attacks of a fingerprint mold made of artificial materials such as silica gel and white glue, a 3D printed artificial limb and the like are avoided, and the anti-counterfeiting effect of the fingerprint identification is improved.

The thin-type optical fingerprint identification device under the screen provided by the embodiment of the invention utilizes the light with a plurality of different wave bands and different incidence angles to reconstruct the three-dimensional characteristics of the user fingerprint, thereby improving the anti-counterfeiting effect of fingerprint identification.

Because the filter layer is formed by non-selective blind bonding, each photosensitive pixel 501 includes at least two types of sub-pixel units. Therefore, each photosensitive pixel 501 can receive signal light of different colors. In order to distinguish signal light with different colors, photosensitive signals or image segments with corresponding colors are output, and corresponding algorithm setting is needed to be carried out on the image drawing and the image processing of the sub-pixel units.

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

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

The image data processing unit may be pre-stored with a noise backup, and after receiving the photosensitive signal input by the sub-pixel unit, the noise backup may compare the received photosensitive signal with the data in the preset noise backup, and deduct the photosensitive signal corresponding to the matching, that is, the photosensitive signal input by the sub-pixel unit in the embedded region 503, and only retain the photosensitive signal input by the sub-pixel unit in the high recognition region 502.

Since the embodiment employs an algorithm to perform noise subtraction on the photosensitive signal output by the embedded region 503, channels formed by all sub-pixel units covered under the high recognition region 502 and the embedded region 503 are all opened. 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 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 for distinguishing similar objects, and no precedence between the two is considered as indicating or implying relative importance. In addition, in the description of the present invention, "a plurality" means two or more unless otherwise specified.

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

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

The above description is only a few embodiments of the present invention, and those skilled in the art can make various changes or modifications to the embodiments of the present invention according to the disclosure of the application document without departing from the spirit and scope of the present invention.

Claims

1. A thin optical fingerprint recognition device under screen, characterized by that includes:

2. The thin underscreen optical fingerprint recognition device according to claim 1, wherein the cover layer and the point light source array are disposed on a self-luminous display screen of an electronic apparatus to which the thin underscreen 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 is composed of one or more luminous pixel units.

3. The thin underscreen optical fingerprint recognition device according to claim 1, wherein the excitation light source is an additionally provided light emitting device.

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

5. The thin underscreen optical fingerprint identification device of claim 1 wherein each high contrast region overlies an inner circular region of an adjacent high contrast region; the inner circular area is illuminated by probe light having an angle of incidence less than the first critical angle.

6. The thin underscreen optical fingerprint recognition device of claim 1 wherein the at least two types of excitation light sources are configured to emit light simultaneously.

7. The thin underscreen optical fingerprint recognition device of claim 1 wherein said at least two types of excitation light sources comprise: the first excitation light source and the second 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 of filter layer and the second type of filter layer are respectively used for allowing the signal light of the first waveband and the signal light of the second waveband to pass through.

8. The thin underscreen optical fingerprint recognition device according to claim 7 wherein said at least two types of excitation light sources further include a third type of excitation light source for emitting probe light of a third wavelength band, said third wavelength band being non-overlapping with the first wavelength band and the second wavelength band; the at least two different filter layers further include a third type filter layer for allowing signal light of a third wavelength band to pass therethrough.

9. The thin underscreen optical fingerprint recognition device of claim 1 wherein each photosensitive pixel comprises three types of sub-pixel units for respectively receiving and sensing signal light of three different wave bands, the number of each type of sub-pixel unit being at least one.

10. The thin underscreen optical fingerprint recognition device according to claim 1, wherein a signal light formed by reflection of the probe light directed to the high contrast area by the object to be recognized illuminates a high recognition area in a ring shape on the photosensitive pixel array, an inner circle boundary of the high recognition area corresponds to the signal light reflected by the probe light at the first critical angle, and an outer circle boundary corresponds to the signal light reflected by the probe light at the second critical angle.

11. The thin underscreen optical fingerprint recognition device according to claim 10 wherein said light-sensitive pixel array is in signal connection with an image data processing unit, each sub-pixel element constituting a channel; the image data processing unit receives photosensitive signals input by the high identification area and the photosensitive signals input by 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 reserves the photosensitive signals input by the sub-pixel units covered by the high identification area.

12. A method for fingerprint recognition using the thin underscreen optical fingerprint recognition device of claim 1, wherein the method comprises:

13. The method of claim 12, wherein the same type of sub-pixel unit receives and senses signal light of the same wavelength band to form an image unit, and the light detecting array includes at least three image units;

in the step of outputting image segments, each of the graph units receives signal light from the same wavelength band and outputs a set of image segments of corresponding colors;

and constructing a three-dimensional stereo image of the object to be recognized according to at least three image segments output by the mapping unit.

14. The method of claim 13, wherein after the step of constructing a three-dimensional stereo 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 the real finger of the user.

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

obtaining a color fingerprint image according to the original images output by at least three mapping 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, and depth information of an object to be identified is restored;

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

16. The method of any of claims 12 to 15, wherein after the step of outputting the original image by the plotting 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 fingerprint image matching comprises the following steps: and matching the obtained skin color of the object to be identified with the skin color of a pre-stored fingerprint image to judge whether the object to be identified is the real finger of the user.

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

the processor is arranged in the electronic equipment which uses or configures the thinned optical fingerprint identification device under the screen.

18. The method of claim 12, wherein the fingerprint recognition is performed using the thinned underscreen optical fingerprint recognition device of claim 10, and in the step of outputting the image segments:

the sub-pixel units covered by the high identification area and the embedded area limited by the circle boundary in the high identification area both output photosensitive signals;

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