CN115273157A

CN115273157A - Fingerprint identification device and fingerprint detection method

Info

Publication number: CN115273157A
Application number: CN202110483619.2A
Authority: CN
Inventors: 李淑娟; 谢詹奇
Original assignee: Silead Inc
Current assignee: Silead Inc
Priority date: 2021-04-30
Filing date: 2021-04-30
Publication date: 2022-11-01

Abstract

The application discloses fingerprint identification device and fingerprint detection method, and the device comprises: a cover layer provided with a fingerprint sensing area; the device comprises an excitation light source, a fingerprint sensing area and a control unit, wherein the excitation light source is used for emitting detection light to an object to be identified and forming a first light spot in the fingerprint sensing area, the first light spot comprises a first preset area and a second preset area, the brightness of the first preset area is lower than that of the second preset area, the excitation light source comprises a first excitation light source and a second excitation light source, the first excitation light source correspondingly forms the first preset area according to a first gray scale interval, and the second excitation light source correspondingly forms the second preset area according to a second gray scale interval; the optical sensor is used for receiving the reflected light signal transmitted from the upper part; when the fingerprint identification device forms a first light spot in the fingerprint sensing area, preset luminous data are obtained according to the reflected light signals, and the characteristics of the object to be identified can be judged based on the preset luminous data. The fingerprint identification method and the fingerprint identification device can judge the characteristics of the object to be identified, and greatly improve the fingerprint identification performance.

Description

Fingerprint identification device and fingerprint detection method

Technical Field

The present application relates to the field of fingerprint identification technologies, and in particular, to a fingerprint identification apparatus and a fingerprint detection method.

Background

The technology of optical fingerprint recognition under screen is rapidly developed and applied because it does not occupy the surface space of electronic devices (e.g., smart phones). As shown in fig. 1, the fingerprint detection module is generally disposed below the display screen 10 of the electronic device, and the fingerprint sensing area is located in the display area of the display screen 10. When the user touches the fingerprint sensing area with finger 100, light source 20 opens and sends the probe light irradiation finger, and the probe light forms the signal light that carries user's fingerprint information after the reflection of user's finger, and signal light can be propagated downwards to optical sensor 40 after gathering through optical assembly 30, obtains the fingerprint data that contain finger ridge and finger valley information after the processing of optical sensor 40.

As shown in fig. 1, the detection light is reflected by the user's finger to form at least two paths: one is a first reflection path 1a formed after being reflected by the skin on the surface of the finger, and the other is a second reflection path 1b formed after the light penetrates through the skin of the human body and is reflected by the blood vessels or tissues in the human body for multiple times, and as the second reflection path 1b is subjected to multiple refraction and multiple reflection, the light loss is more, and the carried signal intensity is low.

However, the degree of dryness and wetness of the fingers of different users is different, and even the same user is in different environments, the degree of dryness and wetness of the fingers is also different. When dry finger touch when fingerprint sensing region goes up, indicate spine and display screen can not guarantee to laminate completely, the part indicates that the interval has the air between spine and the display screen, and the light loss on the second reflection path is more, leads to fingerprint image can become fuzzy, seriously influences the fingerprint identification rate, influences the fingerprint identification performance.

In addition, when the fingerprint is remained (for example, oil stain corresponding to ridge lines) or the false fingerprint image is located on the fingerprint sensing area, the detection light can also generate the reflection light after being incident to the fingerprint remained or the false fingerprint image, and the detection light is transmitted to the optical sensor through the first reflection path, which also causes a certain interference to the fingerprint identification.

Disclosure of Invention

In order to solve at least one technical problem in the prior art, the application provides a fingerprint identification device and a fingerprint detection method, which can judge the characteristics of an object to be identified and greatly improve the existing fingerprint identification performance.

In order to achieve the above purpose, the technical solution provided by the present application is as follows:

a fingerprint recognition device, comprising:

a cover layer provided with a fingerprint sensing area for an object to be identified to contact;

the excitation light source is used for emitting detection light to an object to be identified and forming a first light spot in the fingerprint sensing area, the first light spot comprises a first preset area and a second preset area, the brightness of the first preset area is lower than that of the second preset area, the excitation light source comprises a first excitation light source and a second excitation light source, the first excitation light source correspondingly forms the first preset area according to a first gray scale interval, and the second excitation light source correspondingly forms the second preset area according to a second gray scale interval;

the optical sensor is arranged below the excitation light source and is used for receiving reflected light signals transmitted from the upper part;

when the fingerprint identification device forms a first light spot in the fingerprint sensing area, preset luminous data are obtained according to the reflected light signals, and the characteristics of the object to be identified can be judged based on the preset luminous data.

A fingerprint detection method, the fingerprint detection method comprising:

in response to a fingerprint acquisition request, starting an excitation light source to emit detection light to an object to be identified and form a first light spot in a fingerprint sensing area, wherein the first light spot comprises a first preset area and a second preset area, the brightness of the first preset area is lower than that of the second preset area, the excitation light source comprises a first excitation light source and a second excitation light source, the first excitation light source correspondingly forms the first preset area according to a first gray scale interval, and the second excitation light source correspondingly forms the second preset area according to a second gray scale interval;

when a first light spot is formed in the fingerprint sensing area, preset luminous data are obtained according to the received reflected light signals, and the characteristics of the object to be identified are judged based on the preset luminous data.

According to the fingerprint identification device and the fingerprint detection method provided by the embodiment of the application, the excitation light source emits detection light in different gray scale intervals to form the first light spot, and the first light spot mainly depends on the detection light in the second preset area to pre-acquire fingerprint information. Generally, there are two types of reflected light signals formed after the detection light is reflected by the finger of the user, one is a first reflected light signal carrying finger skin information, the other is a second reflected light signal which is reflected after the detection light is transmitted into the skin of the human body, and the reflection angles of the two types of reflected light signals are different, so that the two types of reflected light signals generate offset distances, and thus the two types of reflected light signals can be distinguished to judge the characteristics of the object to be identified.

The characteristics of the object to be identified can be the dryness and wetness degree of the finger and the authenticity of the finger. For example, when the finger of the user is dry, the second reflected light signal is weak, and the degree of dryness and wetness of the finger is determined by the second reflected light signal, or when the object to be identified is a false fingerprint, the intensity of the second reflected light signal is weak or even does not exist due to the absence of the transmitted light, and the object to be identified is a false fingerprint. Thus, fingerprint recognition performance is improved.

Specific embodiments of the present application are disclosed in detail with reference to the following description and drawings, indicating the manner in which the principles of the application may be employed. It should be understood that the embodiments of the present application 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

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without inventive labor.

FIG. 1 is a schematic diagram of a reflected path of a detecting light in a known embodiment of the prior art;

FIG. 2 is a schematic diagram of a fingerprint identification device according to an embodiment of the present disclosure;

FIG. 3 is a schematic optical path diagram of a fingerprint identification device in one embodiment of the present disclosure;

fig. 4 is a schematic structural diagram of a first light spot in an embodiment of the present disclosure;

fig. 5 is a schematic structural diagram of a first light spot in another embodiment of the present disclosure;

FIG. 6 is a graph showing a comparison of the luminous intensities of a first predetermined region and a second predetermined region in one embodiment of the present disclosure;

FIG. 7 is a graph showing a comparison of the luminous intensities of a first predetermined region and a second predetermined region in another embodiment of the present disclosure;

FIG. 8 is a graph of luminescence intensity in a second spot compared to one embodiment of the present disclosure;

FIG. 9 is a graph of luminescence intensity in a second spot compared to another embodiment of the present disclosure;

FIG. 10 is a schematic outline view of a light emitting region for forming a second spot in one embodiment of the present disclosure;

fig. 11 is a schematic diagram of an optical path in a light emitting region for forming a second light spot in one embodiment of the present description;

FIG. 12 is a diagram illustrating an effect of preset light emission;

FIG. 13 is another effect diagram of the preset light emission;

FIG. 14 is a comparison of detection ray paths for different cover layer thicknesses;

FIG. 15 (a) shows a second light spot formed corresponding to the thickness of the cover layer;

FIG. 15 (b) shows a second light spot formed according to the thickness of another covering layer;

fig. 16 is a flowchart illustrating a fingerprint detection method according to an embodiment of the present disclosure.

Detailed Description

While the invention will be described in detail with reference to the drawings and specific embodiments, it is to be understood that these embodiments are merely illustrative of and not restrictive on the broad invention, and that various equivalent modifications can be effected therein by those skilled in the art upon reading the disclosure.

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," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

The fingerprint identification device and the fingerprint detection method according to the embodiment of the present specification will be explained and explained with reference to fig. 1 to 16. It should be noted that, for convenience of description, like reference numerals denote like parts in the embodiments of the present invention. And for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments, and the descriptions of the same components may be mutually referred to and cited.

The fingerprint identification device and the fingerprint detection method provided by the embodiment of the invention can be applied or configured in scenes including but not limited to screen fingerprint unlocking, user identity authentication, authority acquisition and the like. And may be configured in electronic devices such as smart phones, tablet electronic devices, computers, GPS navigators, smart wearable devices, personal digital assistants, and the like. The electronic device in the embodiment of the present invention may further include other necessary modules or components in order to realize the basic functions of the electronic device. Taking a mobile smart phone as an example, it may further include a communication module, a battery, and the like.

It should be noted that any other necessary modules or components included in the electronic device may be used in any suitable existing configuration. For clearly and briefly explaining the technical scheme provided by the invention, the parts are not described again, and the drawings in the specification are correspondingly simplified.

As shown in fig. 2, the fingerprint recognition device provided by the embodiments of the present specification may include a cover layer 50, an excitation light source 60, and an optical sensor 90 located below the excitation light source 60. That is, the cover layer 50, the excitation light source 60, and the optical sensor 90 are sequentially disposed from top to bottom.

The cover layer 50 has a fingerprint sensing area 503 for contact or depression by an object to be identified (e.g., a user's finger, a printed fingerprint image, a simulated fingerprint film, etc.). Since the detection light emitted from the excitation light source 60 is required to irradiate the object to be identified pressed on the contact area, the cover layer 50 is provided above the excitation light source 60, and may be a protective cover plate for protecting the excitation light source 60, including a cover glass or a sapphire cover plate. In some embodiments, the upper surface of the cover layer 50 may also be provided with a protective layer, such as a protective film. In the embodiment of the present invention, the so-called object to be identified contacts or presses the cover layer 50, and actually the object to be identified may be directly pressed on the cover layer 50 or pressed on the protective layer.

The excitation light source 60 may be a light source configured by an electronic device to which the apparatus is applied, for emitting detection light to an object to be recognized, and may be a self-luminous display screen in which self-luminous units are used as display pixels, for example, an OLED display screen or an LED display screen. The detection light emitted by the excitation light source 60 can be reflected by an object to be identified in the fingerprint sensing area 503 to form a reflected light signal, and the reflected light signal carries fingerprint information partially including finger ridges and finger valleys.

In other embodiments, the fingerprint identification device may also use an internal light source or an external light source to provide the light signal for fingerprint detection. In this case, the fingerprint recognition device may be adapted for use with a non-self-illuminating display, such as a liquid crystal display or other passively illuminating display. Taking the application to the liquid crystal display with the backlight module and the liquid crystal panel as an example, in order to support the fingerprint identification under the liquid crystal display, the excitation light source of the fingerprint identification device can be arranged below the backlight module of the liquid crystal display.

As shown in fig. 2 and 3, in a possible embodiment, the cover layer 50 and the excitation light source 60 can be disposed on a self-luminous display screen configured for an electronic device to which the apparatus is applied, such as an OLED screen or an LED screen. Self-emissive display screens may include an emissive layer, such as an OLED emissive layer or an LED emissive layer, comprising a plurality of emissive pixel cells. The entire area or a partial area of the light-emitting layer corresponding to the cover layer 50 constitutes a light-emitting area of the excitation light source 60, and the excitation light source 60 is composed of a plurality of light-emitting pixel units. The cover layer 50 is a part of the self-luminous display screen, the upper surface of the cover layer 50 can be used as a display area of the self-luminous display screen, and the fingerprint sensing area 503 is located in the display area of the self-luminous display screen, can be a partial area of the display area, and can also be expanded to the whole display area.

The optical sensor 90 may include a photosensitive array and a read circuit and other auxiliary circuits electrically connected to the photosensitive array, which may be fabricated on a chip by a semiconductor process, and may include a photosensitive region and a non-photosensitive region. The photosensitive region can be used for receiving reflected light signals transmitted from the upper part, and the non-photosensitive region can be provided with the reading circuit and other auxiliary circuits.

The optical assembly 80 may further be disposed above the optical sensor 90, and the optical assembly 80 may include a filter layer, a light guide layer, and other optical elements, where the filter layer may be used to filter the ambient light penetrating through the finger, and the light guide layer may be used to guide the reflected light reflected from the surface of the finger to the optical sensor 90 for optical detection. The light guiding layer of the optical assembly 80 may be a lens layer having one or more lens elements, which may be an optical path modulator or an optical path collimator or an array of micro-holes. The reflected light reflected from the finger is collimated or converged by the micro-hole array or the lens unit, and is received by the optical sensor 90 therebelow.

When the finger 200 is in normal condition (for normal finger), the sweat stain or the oil stain of finger 200 skin secretion can make the better laminating of finger ridge and covering layer 50, and indicate the valley not with the covering layer 50 contact, have the air gap to indicate the ridge and indicate the valley reflection ability difference of light, image respectively. The light-sensing area of the optical sensor 90 converts the received reflected light signal into an electrical signal and may further send the fingerprint image to an image data processing unit. 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 processing module in signal connection with the fingerprint image. In this embodiment, the processing module may be provided in an electronic device in which the fingerprint identification device is configured. The processing module can compare and match the generated fingerprint image with a standard fingerprint image stored in the processing module in advance so as to judge whether the object to be identified is the finger information of the user.

In general, a smart phone records fingerprint image information of a real finger of a user in advance and stores the fingerprint image information in a local information base, i.e., a processing module. 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 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 finger of the user. Then, the smartphone completes screen unlocking, permission obtaining, and the like (e.g., payment, login, and the like).

Otherwise, if the comparison result shows that the similarity of the two images is lower than the set value, the generated fingerprint image is considered to be not matched with the standard fingerprint image, and the smart phone continuously maintains the current operation interfaces such as screen locking, permission acquisition failure and the like.

However, when the user's finger 200 is dry (finger dry), since a portion of the finger ridge is not in good contact with the cover layer 50, there is an air gap, and thus the difference in the light reflection capability between the finger ridge and the finger valley is small, so that when the finger is dry, the received valley-ridge signal is weak, the imaging quality is not good, and even if the current object to be recognized is the user's real finger, the recognition cannot be performed.

In addition, when the user's finger 200 touches the cover layer 50, oil stains corresponding to the ridges are left to form a fingerprint residue, or a fake finger (hereinafter, referred to as a fake fingerprint for convenience of description) touches or presses the cover layer 50, a difference between the reflection capacities of the "ridges" and the "valleys" for light can be formed, and a fingerprint image close to the user's finger can be acquired.

In this specification, as shown in fig. 6 and 7, the excitation light source 60 can form a first light spot in the fingerprint sensing region 503 when emitting the detection light, the first light spot includes a first preset region and a second preset region, the brightness of the first preset region is lower than that of the second preset region, the excitation light source includes a first excitation light source and a second excitation light source, the first excitation light source correspondingly forms the first preset region according to a first gray scale interval, and the second excitation light source correspondingly forms the second preset region according to a second gray scale interval.

Correspondingly, in order to form a first preset region and a second preset region with different brightness, the excitation light sources are divided into at least two types, one type of the excitation light sources is used for emitting light according to the gray value of a first gray scale interval to form the first preset region, and the other type of the excitation light sources is used for emitting light according to the gray value of a second gray scale interval to form the second preset region. The gray value in the first gray scale interval is smaller than the gray value in the second gray scale interval. The first excitation light source may emit light according to the same gray scale value in the first gray scale interval, or when the first gray scale interval has a very small value and the light intensity of the first excitation light source is not noticeable to human eyes, the first excitation light source may not emit light at this time. The first excitation light source may emit light in a gradient manner in the first gray scale interval, but the overall light intensity is weak. Similarly, the second excitation light source may emit light according to the same gray scale value in the second gray scale interval, or emit light in a gradient manner in the second gray scale interval, but the light emission intensity of the second predetermined region is stronger as a whole. Preferably, the first excitation light source emits light or does not emit light at the same gray scale value within the first gray scale interval to form the first preset region.

Specifically, each light emitting pixel cell in the excitation light source 60 may include at least one of a red light source, a green light source, and a blue light source. The ratio and/or the gray value of the light signal emitted by each light-emitting pixel unit can be controlled by the light source driving module, so that the brightness distribution of the first light spot can be controlled. The light source driving module may be disposed in the electronic device configured with the fingerprint identification device, and is configured to drive the excitation light source 60 to emit a corresponding light signal according to the brightness distribution in the fingerprint sensing area 503 determined by the processing module, so as to form a light spot.

In some embodiments, the first light spot formed on the fingerprint sensing area 503 by the detection light emitted from the excitation light source 60 may be a circle, an ellipse, a rectangle, or other regular or irregular image, which is not limited in the embodiments of the present invention.

In some embodiments, the excitation light source 60 is used to emit probe light of the same wavelength band or probe light of different wavelength bands to the object to be identified in the cover layer 50. 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.

Specifically, the first light spot may be a light spot formed by combining multiple light sources among the red light source, the green light source, and the blue light source by using different gray values, or a light spot formed by combining a single light source among the red light source, the green light source, and the blue light source by using different gray values. That is, the first light spot may be formed by composite white light having different gray scale values, may be formed by a red light source or a green light source or a blue light source having different gray scale values, or may be formed by a mixed color light source having different gray scale values, for example, the first preset area and the second preset area have different gray scale values and colors. However, in general, the brightness of the first predetermined area is lower than that of the second predetermined area, and since the brightness of the light corresponds to the gray scale value, it can be seen that the first light spot is not a light spot with uniform brightness and is not a pure color light spot.

In this specification, the first light spot is mainly used for pre-acquiring fingerprint information by means of detection light emitted by a second excitation light source corresponding to a second preset area. As shown in fig. 3, in a normal situation, when the user finger 200 touches or presses the fingerprint sensing area 503, the detection light emitted by the second excitation light source is reflected by the user finger 200 to mainly form two reflection paths, one is a first reflection path 2a formed by reflecting the detection light through the skin on the surface of the finger 200, and the other is a second reflection path 2b formed by reflecting the detection light multiple times through the blood vessels or tissues inside the human body skin. For the reflected light on the first reflection path 2a, since it is directly reflected by the skin of the finger 200, the first reflection angle is formed to substantially coincide with the incident angle of the detection light. For the reflected light on the second reflection path 2b, the light loss is more after multiple reflections and refractions, and the formed second reflection angle is necessarily smaller than the incident angle of the detection light. Therefore, the reflection angles of the reflected light signals carried on the first reflection path 2a and the second reflection path 2b are different, and the two reflected light signals generate an offset distance, so that the reflected light signals can be distinguished.

When the dry finger touches or presses the fingerprint sensing area 503, an air gap exists between the cover layer 50, which causes the detection light to be lost more due to the air gap, that is, the light reflected along the second reflection path 2b is less, when the detection light is transmitted into the dry finger and between the dry finger and the cover layer 60, so that the intensity of the reflected light signal carried by the second reflection path 2b is lower, or the second reflection path 2b carries less fingerprint information. When the false fingerprint touches or presses the fingerprint sensing area 503, the detection light is transmitted into the false fingerprint, and the detection light is substantially completely dispersed after transmission because there is no cover above the false fingerprint, so that the second reflection path 2b does not substantially carry the reflected light signal, that is, the second reflection path 2b does not carry fingerprint information. Therefore, by collecting the reflected light signal carried by the second reflection path 2b, the feature of the object to be recognized can be determined.

If the first light spot is a light spot with uniform brightness, the reflected light signal carried by the first reflection path 2a and the reflected light signal carried by the second reflection path 2b will be mutually overlapped, i.e. the two reflected light signals have overlapped portions and cannot be distinguished. In order to distinguish the two reflected light signals, the first light spot is provided with a first preset area and a second preset area, and the reflected light signal after the detection light emitted by the second excitation light source corresponding to the second preset area is reflected enters the first preset area and downwards reaches the optical sensor 90. Since the first predetermined area has a low brightness, it does not interfere with the reflected light signal therebelow, and it is ensured that the fingerprint image formed by the optical sensor 90 can distinguish the reflected light signal transmitted through the first reflection path 2a from the reflected light signal transmitted through the second reflection path 2b.

The first preset area and the second preset area may be a circular pattern, a stripe pattern, a regular pattern or an irregular pattern, which is not limited in the present application. In a preferred embodiment, the first light spot may be a circular light spot, and includes a second predetermined area having a circular ring shape and a first predetermined area located in an inner circular area of the second predetermined area. As shown in fig. 3, by the shape design, the closer to the center of the first predetermined area, the more concentrated the reflected light signal corresponding to the second reflection path 2b, and because the first predetermined area has lower brightness or does not emit light, the reflected light signal generated by the first light spot can be concentrated on the first predetermined area for transmission.

As shown in fig. 12 and 13, the fingerprint information of the object to be identified is pre-acquired by the pre-emission of the first light spot, and the pre-emission data is obtained. The preset luminescence data is specifically a light intensity distribution representing a reflected light signal received by the photosensitive region, and may be an image of the light intensity distribution of the reflected light signal obtained by processing by the optical sensor 90, or a graph of the light intensity distribution of the reflected light signal after further processing. The photosensitive region includes: the fingerprint identification device judges the characteristics of the object to be identified based on the comparison result of the light intensity of the first photosensitive area and the threshold value.

As shown in fig. 12, the first photosensitive area corresponds to the reflected optical signal on the second reflection path 2b, and the second photosensitive area corresponds to the reflected optical signal on the first reflection path 2 a. When the object to be identified is a false fingerprint, the intensity of the light received in the first photosensitive area is close to 0 because the second reflection path 2b does not carry the reflected light signal. When the object to be recognized is a dry finger, the intensity of the reflected light signal carried by the second reflection path 2b is low, so that the intensity of the light received in the first photosensitive region is low but greater than 0.

As shown in fig. 13, the first photosensitive region and the second photosensitive region may be often distinguished by a light emitting boundary. No matter the object to be identified is a normal finger, a dry finger or a fake fingerprint, the reflected light signal carried by the first reflection path 2a can be formed in the photosensitive area, and the reflected light signal carried by the second reflection path 2b is certainly weaker than the reflected light signal carried by the first reflection path 2a, and a boundary necessarily exists between the two.

In some embodiments, the threshold value comprises a first threshold value, and the fingerprint identification device determines that the characteristic of the object to be identified is a false fingerprint when the intensity of the light intensity of the first photosensitive area is not greater than the first threshold value. The first threshold may be 0 or a value close to 0, and when the characteristic of the object to be recognized is determined to be a false fingerprint, the fingerprint detection fails. Taking a smart phone as an example, if fingerprint detection fails, the smart phone continues to maintain the current operation interfaces such as screen locking, permission acquisition failure, and the like.

In some embodiments, the threshold value comprises a second threshold value, and the fingerprint identification device determines that the characteristic of the object to be identified is a dry finger when the intensity of the light of the first photosensitive area is between the first threshold value and the second threshold value. The second threshold is greater than the first threshold, and may be empirically determined. When the light intensity of the first photosensitive area is larger than the second threshold value, the fingerprint identification device judges that the characteristic of the object to be identified is a normal finger, and fingerprint identification can be directly carried out. Or, in order to obtain better fingerprint acquisition effect, the pure-color light spots are emitted again to obtain a clearer fingerprint pattern.

In order to determine the light intensity of the first photosensitive area, a radial light intensity distribution relationship in the photosensitive area may be obtained according to the light intensity distribution received by the previous light emission, as shown in fig. 12, three light intensity peak values F (0), F (d 1), and F (d 2) may be obtained, where F (0) is a minimum peak value, and a reflected light signal carried by the second reflection path 2b may be obtained, and the degree of dryness and wetness of the finger may be determined by determining whether F (0) exceeds a certain threshold, or obtaining an average light intensity value (F (0)) by integrating around the peak value of F (0) to compare the light intensity of the first photosensitive area with the certain threshold.

In some other possible implementations, the fingerprint identification device can further determine that the characteristic of the object to be identified is a wet finger according to the preset light emitting data of the first light spot. In the case of a finger that is too wet, the fingerprint image captured in the photosensitive area is not clear enough due to the absence of air gaps between most of the valleys and the ridges of the finger and the cover layer 50, and adjustments based on this need to be made for better fingerprint identification.

In order to further improve the recognition performance of the device, as shown in fig. 2, a light shielding layer 70 is further disposed between the excitation light source 60 and the optical sensor 90, the light shielding layer 70 is provided with a light transmitting hole 701 for transmitting a reflected light signal formed by reflecting the detection light emitted by the second excitation light source, and the light transmitting hole 701 may be located right above the optical sensor 90. The projection of the first predetermined region on the light shielding layer 70 along the thickness direction of the cover layer 50 falls within the range of the light transmitting hole 701.

By providing the light shielding layer 70, part of the reflected light can be shielded, and the reflected light signal can be incident on the optical sensor 90 only through the light transmitting hole 701, so that the reflected light signal carried by the second reflection path 2b can be collected conveniently through the first preset region and the light transmitting hole 701.

In some possible embodiments, as shown in fig. 4, the projection of the first predetermined region 501 on the light shielding layer 70 is smaller than the opening region of the light hole 701, that is, the first predetermined region 501 is smaller than the projection boundary 701 'of the light hole, and the second predetermined region 502 is located at the periphery of the first predetermined region 501 and surrounds the projection boundary 701' of the light hole, so that the detection light emitted by the second excitation light source is reflected and then passes through the light shielding layer 70 to enter the light hole 701 concentratedly.

In some possible embodiments, as shown in fig. 5, a projection of the first preset region 501 'on the light shielding layer 70 substantially coincides with an opening region of the light hole 701, that is, the first preset region 501' is smaller than a projection boundary 702 'of the light hole, and the second preset region 502' is located at the periphery of the first preset region 501 'and is located at the periphery of the projection boundary 702' of the light hole, so that when the detection light emitted by the second excitation light source enters the light hole 701 after being reflected, an entering region is consistent with the first preset region 501', and it can be considered that the detection light emitted by the second excitation light source enters only through the first preset region 501', and the reflected light signals collected by the optical sensor 90 located below the light hole 701 are more concentrated, which is more beneficial for determination.

Further, along the thickness direction of the cover layer 50, the projection position of the center position of the first predetermined region 501' on the light shielding layer 70 coincides with the center of the light hole 701. That is, the area of the first predetermined region 501' is the opening area of the light-transmitting hole 701. The area of the second preset area 502' may be enlarged to the display area of the entire cover layer 50, so that the fingerprint sensing area 503 corresponding to the first light spot may be the display area of the entire cover layer 50. However, when the light shielding layer 70 is provided, if the fingerprint sensing region 503 is expanded to the entire display region of the cover layer 50, when the object to be identified is in contact with the cover layer 50, the reflected light signal may not be collected if the position of the object to be identified is greatly deviated from the position of the light transmitting hole 701, and therefore the area of the second predetermined region 501' should not be too large, and should be disposed near the projection boundary 702' of the light transmitting hole and near the projection boundary 702' of the light transmitting hole.

In some embodiments, the excitation light source 60 is further configured to emit detection light to the object to be identified and form a third light spot in the fingerprint sensing area 503, where the third light spot and the first light spot are sequentially emitted, and the fingerprint identification device can determine the feature of the object to be identified based on the third light spot and the first light spot.

In this embodiment, the device can send out the third light spot earlier and acquire fingerprint information, sends out first light spot again and acquires and predetermine luminous data to judge the characteristic of waiting to discern the object based on third light spot and first light spot. Thus, the first light spot can be matched with a normal fingerprint identification process. Generally, the light spots for fingerprint identification are light spots with uniform brightness or light spots with uniformly gradually changing brightness from the edge of the fingerprint sensing area 503 to the center of the fingerprint sensing area 503 to obtain sufficient fingerprint information. However, when the object to be recognized is characterized by a dry finger and a fake fingerprint, or the brightness of the light spot is too strong and too dark, the recognition effect is not good, and at this time, the first light spot can be used for assisting in recognition, and a corresponding recognition action is taken based on the judgment of the first light spot.

In some possible scenes, when the object to be identified is a false fingerprint, when the third light spot is emitted, a fingerprint image close to the finger of the user can be acquired in the photosensitive area. However, when the first light spot is emitted, the object to be identified can be judged to be a false fingerprint, so that the third light spot and the first light spot are different in judgment of the object to be identified and are judged to be false fingerprints, and fingerprint detection fails.

In some possible scenes, when the object to be identified is a normal finger and the third light spot is emitted, a relatively clear fingerprint image can be acquired in the photosensitive area. And when the first light spot is emitted, the object to be identified can be judged to be a normal finger, the fingerprint identification device carries out fingerprint identification based on the third light spot, namely, the fingerprint image acquired by directly utilizing the third light spot is compared with the standard fingerprint image stored in the information base, so that the fingerprint identification time is reduced.

Or, in some possible scenarios, when the object to be identified is a dry finger, and the third light spot is a light spot with a uniformly gradually changing brightness from the edge of the fingerprint sensing area 503 toward the center of the fingerprint sensing area 503, the fingerprint identification apparatus may also directly compare the fingerprint image acquired by using the third light spot with the standard fingerprint image stored in the information base, thereby improving the identification capability of the dry finger.

In this specification, after the characteristic of the object to be recognized is judged to be finger-dry, further adjustment can be made for the finger-dry condition. As shown in fig. 10, the light source driving module adjusts the excitation light source 60 to form a second light spot 703 in the fingerprint sensing area 503, and the fingerprint identification device performs fingerprint identification based on the second light spot 703. The second light spot 703 is a gradual light spot, and the brightness of the second light spot 703 is reduced from the edge of the fingerprint sensing area 503 toward the center of the fingerprint sensing area 503 uniformly or non-uniformly.

It can be seen that in some embodiments, when it is determined that the feature of the object to be identified is a dry finger, fingerprint information needs to be collected through at least two times of light emission, where the first light spot is a previous light emission and the second light spot 703 is a subsequent light emission. Alternatively, in the embodiment including the third light spot, the fingerprint information needs to be acquired through at least three times of light emission, and the third light spot, the first light spot and the second light spot 703 are sequentially included.

In the embodiment shown in fig. 8 and 9, the gradient of the second light spot 703 is smaller than the first light spot compared to the first light spot, and the brightness of the second light spot 703 is lower the closer to the center of the fingerprint sensing area 503. The manner of adjusting the brightness of the second light spot 703 is described in the description of the first light spot, and the description of the present application is omitted here.

The advantages of the second light spot 703 for dry finger fingerprint acquisition will be described below in conjunction with the imaging principle of the fingerprint identification device:

according to the total reflection principle, when light enters the light-thinning medium from the optically dense 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 dense medium without being transmitted into the light-thinning medium. Wherein the critical angle is the total reflection angle.

When a normal finger is pressed against the fingerprint sensing area 503, there is typically a sweat stain between the finger ridge and the cover layer 50. With respect to the cover layer 50 (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 larger the refractive index of the optically thinner medium is, the larger the corresponding total reflection angle is.

The total reflection angle of the detection light at the interface between the cover layer 50 and the air gap of the finger valley is defined as a first critical angle θ 1, the total reflection angle of the detection light at the interface between the cover layer 50 and the finger ridge is defined as a second critical angle θ 2, and 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 finger valley and the finger ridge, and most of the refracted light reaches the finger surface. The light refracted at the valleys is reflected by the skin of the valleys, and is reflected twice, three times or more at the interface between the air gap and the cover layer 50, resulting in more loss. Therefore, the fingerprint image obtained in this case exhibits an effect of dark valleys and bright ridges, and has poor contrast.

When the incident angle of the incident light is between the first critical angle theta₁And a second critical angle theta₂When the light is incident, the incident light is totally reflected at the valleys and partially reflected at the ridges. Therefore, the fingerprint image obtained after reflection in this case has the effect of bright valleys and dark ridges, and the contrast between bright and dark is optimal. Therefore, the ridge-valley characteristics of the fingerprint image obtained after the reflection of the two incident light rays are just opposite, and the incident angle is smaller than the first critical angle theta₁The contrast of the fingerprint image obtained after the incident light is reflected is not good enough, and the quality of the fingerprint image can be influenced to a certain degree.

The closer to the center of the fingerprint sensing area 503, the more the proportion of incident light rays emitted by the excitation light source 60 with an incident angle smaller than the first critical angle θ 1 is, in short, the closer to the area directly above the excitation light source 60, the sharper fingerprint image cannot be obtained. Therefore, by setting the second light spot 703 to be a gradual change light spot, the brightness of the second light spot 703 is decreased from the edge of the fingerprint sensing area 503 toward the center of the fingerprint sensing area 503, and the incident angle smaller than the first critical angle θ can be reduced₁The ratio of incident light rays to reduce the influence on the fingerprint image, thereby improving the definition of the fingerprint image and solving the problem of finger dryness.

In this specification, in order to better solve the problem of dry fingers, it is also necessary to determine the thickness of the cover layer 50 above the excitation light source 60 and adjust the light emitting parameters of the second light spot 703 based on the thickness of the cover layer 50.

As shown in fig. 14, the angle of incidence at which the probe light emitted by the excitation light source 60 reaches the fingerprint sensing area 503 is different for different thicknesses of the cover layer 50. Generally speaking, the thicknesses of the cover layers 50 configured for different electronic devices are different, and when the cover layer 50 is configured with a first thickness and a detection light emitted by a certain light-emitting pixel unit is incident to a certain position F3 of the fingerprint sensing area 503, the incident angle is just the first critical angle θ 1, and just total reflection occurs; however, when the covering layer 50 is configured to have a second thickness, that is, when the covering layer is increased from the first thickness to the second thickness, when the detection light emitted from the same light-emitting pixel unit is incident to the same position F3', the incident angle is θ and smaller than the first critical angle θ 1, so that the incident light is partially refracted + partially reflected, and the intensities of the reflected light signals carried by the two cases are different. This is because the difference caused by the different optical paths of the same light emitting pixel unit in the cover layer 50, that is, the difference necessarily exists in the fingerprint images presented by the different thicknesses of the cover layer 50, and it is necessary to determine the thickness of the cover layer 50 according to the preset light emitting data of the first light spot, and then adjust the light emitting parameter of the second light spot 703 based on the thickness of the cover layer 50.

As shown in fig. 3, when the excitation light source 60 emits the detection light, there is a third reflection path 2 in addition to the reflection by the object to be recognized_C. The detection light emitted by the excitation light source 60 is reflected and/or refracted on three types of interfaces, the first type of interface is the interface between the excitation light source 60 (or the luminescent layer where the excitation light source 60 is located) and the cover layer 50, the second type of interface is the interface between the cover layer 60 and the object to be identified, and the third type of interface is the light which penetrates through the skin of the human body and is reflected by the internal blood vessels or tissues for multiple times.

The optical paths of the detection light rays when reflected on the three types of interfaces are different, so that three types of image areas with different relative positions, namely a first image, a second image and a third image, can be obtained, wherein the three types of image areas correspond to the reflected light signals of the first reflected path 2a, the second reflected path 2b and the third reflected path 2c shown in fig. 3 respectively.

Wherein the combination of the first image and the third image allows to know the thickness information of the cover layer 50. For example, the relative distance between the first image and the third image is proportional to the thickness of the overlay 50, and the thickness information of the overlay 50 can be known using a simple linear transformation. The combination of the first image and the second image may be used to determine the characteristics of the object to be recognized, for example, the humidity of the finger of the user and the authenticity of the finger may be determined, because the transmission degree of light is different for a normal finger compared with a dry finger and a fake fingerprint, which may be specifically described in the above principle, and is not repeated in this application.

In order to obtain the relative distance between the first image and the third image, as shown in fig. 5, the projection of the first predetermined region 501' projected on the light shielding layer 70 along the thickness direction of the cover layer 50 substantially coincides with the light transmitting hole 701. The first image and the third image are sets of reflected light signals carried by two types of reflection paths corresponding to the second preset region 502', respectively, and the area of the second preset region 502' should not be too large and should be set at a position close to the projection boundary 702' of the light-transmitting hole.

As shown in fig. 12, the second photosensitive area has a first light-emitting boundary and a second light-emitting boundary, the first light-emitting boundary is located at the boundary of the first photosensitive area and the second photosensitive area, the second light-emitting boundary corresponds to the peak value F (d 2) of the reflected light signal of the detection light emitted by the second excitation light source reflected at the interface between the excitation light source 60 and the cover layer 50, the first light-emitting boundary corresponds to the peak value F (d 1) of the reflected light signal of the detection light emitted by the second excitation light source reflected at the interface between the cover layer 50 and the object to be identified, and the fingerprint identification device can further determine the thickness of the cover layer based on the first light-emitting boundary and the second light-emitting boundary. Wherein a relative distance D = D2-D1 between the first light emitting boundary and the second light emitting boundary, D having a linear relationship with the thickness D of the cover layer 50, to judge the thickness of the cover layer 50.

In some possible embodiments, when the feature of the object to be recognized is dry finger, the processing module may determine the light emitting area of the excitation light source 60 for forming the second light spot 703 based on the thickness of the covering layer 50, the area of the light-transmitting hole 701 and the first critical angle θ 1, and accordingly, determine the light emitting range of the excitation light source 60.

Specifically, the light emitting area of the excitation light source 60 for forming the second light spot 703 may be expanded by at least 2d outwardly based on the opening area of the light-transmitting hole 701₃Side length of (1), wherein d₃＝D×tanθ₁. The light emitting area of the second light spot 703 may be as shownCircular as shown, or other shapes including areas of the circle, such as square, triangle, rectangle, etc.

Normally, when the user's finger touches the fingerprint sensing area 503, the incident angle of the incident light is smaller than the first critical angle θ₁In the process, the fingerprint image obtained after reflection shows the effect of dark valleys and bright ridges, but the contrast is poor. When the incident angle of the incident light is between the first critical angle theta₁And a second critical angle theta₂When the fingerprint image is reflected, the fingerprint image obtained after reflection has the effect of bright valley and dark ridge, and the light-dark contrast is optimal. Since the brightness of the outer ring of the second light spot 703 is greater than that of the inner ring, in order to avoid the influence of the incident light with higher brightness and an incident angle smaller than the first critical angle θ 1 on the fingerprint image, the blocking layer 70 can be used to eliminate the incident light, so that only the incident light with an incident angle between the first critical angle θ 1 and the second critical angle θ 2 is allowed to enter the light hole 701.

Further, when the incident angle of the probe light emitted from the excitation light source 60 is larger than the second critical angle θ 2, then the probe light is totally reflected at both the ridge and the valley, so that the ridge and the valley show no or small difference, and thus, the fingerprint image is not obtained at a far distance from the excitation light source. Therefore, d can also be set₃≤D×tanθ₂So as to prevent the incident light with higher brightness and incident angle larger than the second critical angle θ 2 from entering the light transmission hole 701, and reduce the influence on the fingerprint image.

In some embodiments, when the feature of the object to be recognized is determined to be a dry finger, the processing module may further determine a gray scale gradient in the light emitting region of the excitation light source 60 for forming the second light spot 703 based on the thickness of the covering layer 50 and a preset rule, and accordingly, determine a gray scale value distribution of the light emitting region of the excitation light source 60.

For convenience of description, for a certain position of the fingerprint sensing area 503, an incident angle smaller than the first critical angle θ will be emitted towards the position₁Is defined as a first light-emitting pixel unit, emits light toward the position with an incident angle between a first critical angle theta₁And a second critical angle theta₂Is defined as the second light emissionA light pixel unit emitting light toward the position with an incident angle greater than a second critical angle theta₂The light emitting pixel unit of (2) is defined as a third light emitting pixel unit. For different thicknesses of the covering layer 50, the numbers of the first light-emitting pixel unit, the second light-emitting pixel unit and the third light-emitting pixel unit corresponding to the same position are different.

Taking the first light-emitting pixel unit as an example, as shown in fig. 14, when the thicknesses of the covering layers 50 are different, the incident angle is smaller than the first critical angle θ toward the F3 position₁The number of the first light emitting pixel units is different, and it is understood that when the thickness of the covering layer 50 is increased, the incident angle is smaller than the first critical angle theta towards the F3 position₁The number of the first light emitting pixel units is increased. By analogy with the F1 position and the F2 position, the ranges of the first light-emitting pixel units corresponding to the same positions with different thicknesses are different. It can be seen that when applied to electronic devices with different thicknesses of the cover layer 50, the gray scale gradient of the second spot 703 for post-illumination needs to be adjusted to reduce the incident angle smaller than the first critical angle θ₁The influence of the incident light on the fingerprint image better solves the problem of finger drying.

Specifically, the preset rule may include the following steps for adjusting the gray scale gradient in the light emitting region of the excitation light source 60 for forming the second light spot 703:

step 1: from the fingerprint sensing area 503 into m position cells F₁,…,F_mThe area of each position unit can be the area of N luminous pixel units, N>1, the shape of the location unit may be triangular; or rectangular; or circular; the fingerprint sensing area may be a light emitting area of the first light spot that emits light before, or may be a light emitting area of the second light spot 703 that is determined according to the thickness of the cover layer 50.

Step 2: establishing a geometric mapping relationship between the light-emitting layer (light-emitting pixel unit) and the light-sensing region (light-sensing pixel unit) in the entire fingerprint sensing area 503 according to the thickness of the covering layer 50, and constructing a position matrix; wherein, an initial gray value matrix I corresponding to the first light spot can be obtained in the preset light-emitting data, and the matrix element is I_ij(ii) a i, j are positive integersAnd (4) counting. Wherein the initial gray value matrix I may be a gray value matrix corresponding to the first light spot. There is a certain geometrical mapping between the fingerprint sensing area 503 and the corresponding photosensitive area. This geometrical mapping is also determined in case the thickness of the cover layer 50 is determined, i.e. in case the optical path distance of the reflected light from the fingerprint sensing area 503 to the corresponding photosensitive area is determined.

And step 3: with one of the position units F₁Centered, a k-order position matrix can be constructed with X matrix elements_ijI, j are positive integers and (1 ≤ i, j ≤ k), wherein the value of each matrix element represents the light emission contribution of the corresponding light-emitting pixel; mapping the initial gray value matrix I through the position matrix X to obtain the position unit F of the luminescent layer (luminescent pixel unit)₁The luminescence contribution of (d);

introduction of statistical rules: by the position unit F₁Centered, configurable k-order position matrix L₁According to a geometric mapping relationship and a first critical angle theta₁A second critical angle theta₂Determined geometric model acquisition and location unit F₁The distribution of the corresponding first, second and third light-emitting pixel units; position matrix L₁The value of the element (b) can be selected from alpha, beta and gamma; α is used to represent a first light-emitting pixel unit, β is used to represent a second light-emitting pixel unit, and γ is used to represent a third light-emitting pixel unit; alpha, beta, gamma can be in [ -1,1]Value composition is obtained; when the value is-1, the opposite position unit L is indicated₁Is the smallest, and when the value is 1, it indicates a corresponding position unit L₁Is maximized, e.g., the following k-order matrix L₁：

According to the number and the weight of the three types of light-emitting pixel units, statistics can be carried out;

respectively show the position unit F₁Above from three types of light emission contributions.

For the same reason, in the position cell F₂The above luminescence contributions from the three types of light are:

by analogy, m position units F₁,…,F_mThe light contribution from the above three types of light is:

wherein the position matrix L₂,…,L_mIs obtained by dividing the matrix L₁Performing corresponding translation and conversion operation according to the plane position relation of the m position units;

and 4, step 4: given that the fingerprint sensing area 503 is divided into m position units, and each position unit is imaged in the photosensitive area, and there is a corresponding relationship with the photosensitive area, according to the geometric mapping relationship, the photosensitive gray values P corresponding to the m position units can be counted based on the fingerprint image information acquired from the photosensitive area₁,…P_m；

And 5: to obtain

Solving to obtain a, b and c as compensation parameters;

step 6: gradually increasing or decreasing the gray value gradient in the initial gray value matrix I to serve as a new gray value matrix I and determine:

then substituting the compensation parameters a, b and c, and solving to obtain multiple groups of P₁,…P_mArray of numbers;

and 7: from a plurality of groups P₁,…P_mIn the series, one or more sets of target series are obtained according to the screening conditions. The screening conditions were that the arithmetic mean of the target series was greater than zero and the standard deviation was minimal.

And 8: selecting the latest gray value matrix corresponding to one group of target number sequence as the light emitting matrix of the second light spot by using one or more groups of target number sequences obtained in the step 7; the above steps may be repeated one or more times to obtain the optimal second light spot gray scale gradient.

As shown in fig. 15 (a) and 15 (b), the gray scale gradient of the second light spot 703 adjusted by the above steps has a significant difference under different thicknesses of the covering layer 50, so that the gray scale gradient of the second light spot 703 can be adjusted according to the thickness of the covering layer 50 to better solve the problem of dry fingers for different types of electronic devices.

The formed second light spot 703 can acquire fingerprint information by one-time light emission or by multiple light emission. In some embodiments, the second light spot 703 may include a plurality of sub-light spots displayed in a sequential order, the sub-light spots being any one of a circular pattern, a circular ring pattern, a stripe pattern, or a chessboard pattern. The sub-spots can emit light in sequence according to different gray values, for example, for sub-spots with circular or annular patterns, the sub-spots can emit light from the outer ring to the inner ring in sequence, and for sub-spots with stripe patterns or chessboard patterns, the sub-spots can emit light in sequence according to a predetermined sequence, so that the plurality of sub-spots are spliced to obtain the second light spot 703 after emitting light, and sub-images obtained after the sub-spots emit light are spliced according to the light emitting sequence to obtain a fingerprint image. In this embodiment, when the plurality of sub light spots emit light according to the sequence, the fingerprint information is spliced by the processing module to acquire complete fingerprint information.

The present specification also provides a fingerprint detection method, as shown in fig. 1 to 16, the fingerprint detection method including the steps of:

step S10: in response to a fingerprint acquisition request, starting an excitation light source 60 to emit detection light to an object to be identified and form a first light spot in the fingerprint sensing area 503, wherein the first light spot comprises a first preset area and a second preset area, the brightness of the first preset area is lower than that of the second preset area, the excitation light source 60 comprises a first excitation light source and a second excitation light source, the first excitation light source correspondingly forms the first preset area according to a first gray scale interval, and the second excitation light source correspondingly forms the second preset area according to a second gray scale interval;

step S20: when the first light spot is formed in the fingerprint sensing area 503, preset light emitting data is obtained according to the received reflected light signal, and the characteristic of the object to be recognized is determined based on the preset light emitting data.

In some embodiments, the fingerprint detection method comprises:

step S30: and judging whether the object to be identified is a false fingerprint or not based on the comparison result of the light intensity of the first photosensitive area and the first threshold.

In some embodiments, the fingerprint detection method includes:

step S40: judging whether the object to be identified is a dry finger or not based on the comparison result of the light intensity of the first photosensitive area and the second threshold;

step S50: after the object to be identified is determined to be a dry finger, the excitation light source 60 is controlled to form a second light spot 703 in the fingerprint sensing area 503, and the brightness of the second light spot 703 is reduced from the edge of the fingerprint sensing area 503 to the center of the fingerprint sensing area 503 uniformly or non-uniformly.

The fingerprint detection method can achieve the technical problems solved by the fingerprint identification device and correspondingly achieve the technical effects of the above embodiments, and specific details of the present application are not repeated herein.

The above embodiments are merely illustrative of the technical concepts and features of the present application, and the purpose of the present invention is to enable those skilled in the art to understand the content of the present application and implement the present application, and not to limit the protection scope of the present application. All equivalent changes and modifications made according to the spirit of the present application should be covered in the protection scope of the present application.

All articles and references disclosed, including patent applications and publications, are hereby incorporated by reference for all purposes. The term "consisting essentially of …" describing a combination shall include the identified elements, components, parts or steps as well as other elements, components, parts or steps that do not materially affect the basic novel characteristics of the combination. The use of the terms "comprising" or "including" to describe combinations of elements, components, or steps herein also contemplates embodiments that consist essentially of such elements, components, or steps. By using the term "may" herein, it is intended to indicate that any of the described attributes that "may" include are optional.

A plurality of elements, components, parts or steps can be provided by a single integrated element, component, part or step. Alternatively, a single integrated element, component, part or step may be divided into separate plural elements, components, parts or steps. The disclosure of "a" or "an" to describe an element, ingredient, component or step is not intended to foreclose other elements, ingredients, components or steps.

It is to be understood that the above description is intended to be illustrative, and not restrictive. Many embodiments and many applications other than the examples provided will be apparent to those of skill in the art upon reading the above description. The disclosures of all articles and references, including patent applications and publications, are hereby incorporated by reference for all purposes.

Claims

1. A fingerprint recognition apparatus, comprising:

the device comprises an excitation light source, a fingerprint sensing area and a control unit, wherein the excitation light source is used for emitting detection light to an object to be identified and forming a first light spot in the fingerprint sensing area, the first light spot comprises a first preset area and a second preset area, the brightness of the first preset area is lower than that of the second preset area, the excitation light source comprises a first excitation light source and a second excitation light source, the first excitation light source correspondingly forms the first preset area according to a first gray scale interval, and the second excitation light source correspondingly forms the second preset area according to a second gray scale interval;

2. The fingerprint recognition device of claim 1, wherein the cover layer and the excitation light source are disposed on a self-luminous display screen, the self-luminous display screen comprising a light-emitting layer comprising a plurality of light-emitting pixel units, the excitation light source being comprised of the plurality of light-emitting pixel units.

3. The fingerprint recognition device according to claim 1, wherein said optical sensor is provided with a photosensitive area, said predetermined light emission data is specifically indicative of a light intensity distribution of a reflected light signal received by said photosensitive area, and said photosensitive area comprises: the fingerprint identification device comprises a first photosensitive area and a second photosensitive area, wherein the light intensity received by the first photosensitive area is smaller than that received by the second photosensitive area, and the fingerprint identification device judges the characteristics of an object to be identified based on the comparison result of the light intensity of the first photosensitive area and a threshold value.

4. The fingerprint recognition device according to claim 3, wherein the threshold value comprises a first threshold value, and when the intensity of the light of the first photosensitive area is not greater than the first threshold value, the fingerprint recognition device determines that the characteristic of the object to be recognized is a false fingerprint.

5. The fingerprint recognition device according to claim 3, wherein the threshold value comprises a second threshold value, and when the intensity of the light of the first photosensitive area is between the first threshold value and the second threshold value, the second threshold value is greater than the first threshold value, the fingerprint recognition device determines that the object to be recognized is characterized as a dry finger.

6. The fingerprint identification device according to claim 3, wherein said excitation light source is further configured to emit detection light to the object to be identified and form a third light spot in the fingerprint sensing area, said third light spot and said first light spot are emitted sequentially in order, and said fingerprint identification device is capable of determining the characteristic of the object to be identified based on said third light spot and said first light spot.

7. The fingerprint recognition device according to claim 6, wherein the third light spot is a light spot with uniform brightness or a light spot with uniform gradual brightness from the edge of the fingerprint sensing area to the center of the fingerprint sensing area.

8. The fingerprint recognition apparatus according to claim 7, wherein the threshold value comprises a second threshold value, and when the intensity of the light of the first photosensitive area is greater than the second threshold value, the fingerprint recognition apparatus determines that the feature of the object to be recognized is a normal finger, and performs fingerprint recognition based on the third light spot.

9. The fingerprint identification device according to claim 5 or 6, wherein the fingerprint identification device comprises a light source driving module, when the fingerprint identification device determines that the feature of the object to be identified is dry finger, the light source driving module is configured to adjust the excitation light source to form a second light spot in the fingerprint sensing area, and the fingerprint identification device performs fingerprint identification based on the second light spot.

10. The fingerprint recognition apparatus according to claim 9, wherein the second light spot is a gradient light spot, and the brightness of the second light spot is uniformly or non-uniformly decreased from the edge of the fingerprint sensing area toward the center of the fingerprint sensing area.

11. A fingerprint recognition device as claimed in claim 3, wherein said device comprises: the light shielding layer is arranged between the optical sensor and the excitation light source, the light shielding layer is provided with a light hole for transmitting a reflected light signal formed after the detection light emitted by the second excitation light source is reflected, and along the thickness direction of the covering layer, the projection of the first preset area projected on the light shielding layer falls into the range of the light hole.

12. The fingerprint recognition device according to claim 11, wherein the second photosensitive area has a first light-emitting boundary and a second light-emitting boundary, the first light-emitting boundary is located at an intersection of the first photosensitive area and the second photosensitive area, the second light-emitting boundary corresponds to a peak value of a reflected light signal of the detection light emitted by the second excitation light source reflected at an interface between the excitation light source and the cover layer, the first light-emitting boundary corresponds to a peak value of a reflected light signal of the detection light emitted by the second excitation light source reflected at an interface between the cover layer and the object to be recognized, and the fingerprint recognition device is further capable of determining the thickness of the cover layer based on the first light-emitting boundary and the second light-emitting boundary.

13. The fingerprint identification device of claim 12, wherein a projection of the first predetermined area onto the light blocking layer substantially coincides with the light transmission hole along a thickness direction of the cover layer.

14. The fingerprint recognition device according to claim 12, wherein the fingerprint recognition device comprises a processing module, and when the object to be recognized is determined to be characterized as a dry finger, the processing module determines the light emitting area of the excitation light source for forming the second light spot based on the thickness of the cover layer, the area of the light transmission hole, and a first critical angle corresponding to the total reflection angle of the detection light at the interface between the cover layer and the finger valley gap.

15. The fingerprint recognition device according to claim 12, wherein the fingerprint recognition device comprises a processing module, and when the characteristic of the object to be recognized is determined to be a dry finger, the processing module determines a gray scale gradient in the light emitting region of the excitation light source for forming the second light spot based on the thickness of the cover layer and a preset rule.

16. The fingerprint recognition apparatus of claim 10, wherein the second light spot comprises a plurality of sub-light spots displayed in a sequential order, and the sub-light spots are any one of a circular pattern, a circular ring pattern, a stripe pattern, or a chessboard pattern.

17. A fingerprint detection method, characterized in that the fingerprint detection method comprises:

18. The fingerprint sensing method according to claim 17, wherein said predetermined light emission data is specifically indicative of a light intensity distribution of a reflected light signal received by a photosensitive area on the optical sensor, the photosensitive area comprising: the light intensity received by the first photosensitive area is smaller than that received by the second photosensitive area; the fingerprint detection method comprises the following steps:

and judging whether the object to be identified is a false fingerprint or not based on the comparison result of the light intensity of the first photosensitive area and the first threshold.

19. The fingerprint sensing method of claim 17, wherein the predetermined illumination data is specifically indicative of an intensity distribution of the reflected light signal received by a photosensitive area on the optical sensor, the photosensitive area comprising: the light intensity received by the first photosensitive area is smaller than that received by the second photosensitive area; the fingerprint detection method comprises the following steps:

judging whether the object to be recognized is a dry finger or not based on the comparison result of the light intensity of the first photosensitive area and a second threshold value;

and after the object to be identified is judged to be a dry finger, controlling the excitation light source to form a second light spot in the fingerprint sensing area, wherein the brightness of the second light spot is reduced uniformly or non-uniformly from the edge of the fingerprint sensing area to the center of the fingerprint sensing area.