WO2020227937A1

WO2020227937A1 - Method for fingerprint recognition, fingerprint recognition device, and terminal apparatus

Info

Publication number: WO2020227937A1
Application number: PCT/CN2019/086888
Authority: WO
Inventors: 钟松锦; 杜灿鸿
Original assignee: 深圳市汇顶科技股份有限公司
Priority date: 2019-05-14
Filing date: 2019-05-14
Publication date: 2020-11-19
Also published as: CN110291530B; CN110291530A

Abstract

A method for fingerprint recognition, a fingerprint recognition device (300), and a terminal apparatus (10). The method comprises: when a finger presses a fingerprint detection region (103, 210) of a display screen (120, 200) of a terminal apparatus (10), detecting a reflected light signal generated after a target light signal emitted from a light source (310) has been reflected by a finger, wherein a target light spot (311) formed from the target light signal at the fingerprint detection region (103, 210) comprises a first region (S1) and a second region (S2), the target light signal comprises a first light signal corresponding to the first region (S1) and a second light signal corresponding to the second region (S2), gray-scale values of three primary colors (RGB) of the first light signal are not equal to gray-scale values of three primary colors (RGB) of the second light signal, and the first region (S1) and the second region (S2) do not completely overlap with each other (S410); and acquiring fingerprint data of the finger according to the reflected light signal (S420). The method for fingerprint recognition, the fingerprint recognition device (300), and the terminal apparatus (10) can increase a fingerprint recognition area.

Description

Method for fingerprint identification, fingerprint identification device and terminal equipment

Technical field

This application relates to the field of fingerprint identification, and in particular to methods, fingerprint identification devices and terminal equipment for fingerprint identification.

Background technique

Concentrating under-screen optical fingerprints are mainly used under Organic Light-Emitting Diode (OLED) screens. Affected by OLED stacking, the imaging clarity of under-screen optical fingerprints in a normal temperature environment is elliptical. For example, as shown in FIG. 1A, the effective recognition area of the fingerprint image occupies less than 50% and is basically in the middle of the image. Among them, the signals of the lower left and upper right image corners are much weaker than the other two diagonal corners. However, in a low temperature environment, due to changes in the characteristics of the finger, the middle of the fingerprint image will become blurred and the overall contrast will decrease. For example, as shown in FIG. 1B, the effective recognition area of the fingerprint image will eventually decrease sharply, which seriously affects the recognition rate of the fingerprint.

Summary of the invention

This application provides a method for fingerprint identification, a fingerprint identification device and a terminal device, which can increase the fingerprint identification area.

In a first aspect, a method for fingerprint identification is provided. The method includes: when a finger presses a fingerprint detection area of a display screen of a terminal device, detecting the reflection formed by the reflection of the target light signal emitted by the light source after irradiating the finger Light signal, wherein the target light spot formed by the target light signal in the fingerprint detection area includes a first area and a second area, and the target light signal includes a first light signal corresponding to the first area and For the second optical signal corresponding to the second area, the gray values of the three primary colors of red, green, and blue of the first optical signal and the gray values of the three primary colors of RGB of the second optical signal are not equal, and the first The area does not completely overlap the second area; and the fingerprint data of the finger is acquired according to the reflected light signal.

With reference to the first aspect, in an implementation manner of the first aspect, the shape of the target light spot is a circle.

In combination with the first aspect and the foregoing implementation manners, in another implementation manner of the first aspect, the shape of the first region is an axisymmetric strip shape, and the axis of symmetry in the long axis direction of the first region is the first A straight line, the first straight line passes through the center point of the target light spot, the second area is an area of the target light spot other than the first area, the RGB three primary colors of the first light signal The gray value of is smaller than the gray value of the RGB three primary colors of the second light signal.

Combining the first aspect and the foregoing implementation manners thereof, in another implementation manner of the first aspect, a straight line passing through the center point of the target spot and perpendicular to the first straight line is a second straight line, and the target spot Any two points located on the second straight line are the first point and the second point, and the distance from the first point to the center point of the target spot is smaller than the second point to the center point of the target spot The gray value of the color of the light signal corresponding to the first point is smaller than the gray value of the color of the light signal corresponding to the second point.

In combination with the first aspect and the foregoing implementation manners of the first aspect, in another implementation manner of the first aspect, the gray value of the color of the light signal corresponding to the point on the second straight line in the target spot is distributed in a parabolic shape Or elliptical distribution.

With reference to the first aspect and the foregoing implementation manners, in another implementation manner of the first aspect, the angle from the first straight line to the horizontal line is an acute angle.

With reference to the first aspect and the foregoing implementation manners, in another implementation manner of the first aspect, the angle between the first straight line and the horizontal line is equal to 45°.

In combination with the first aspect and the foregoing implementation manners, in another implementation manner of the first aspect, the target light spot is a pure color light spot.

In combination with the first aspect and the foregoing implementation manners, in another implementation manner of the first aspect, the target light spot is green, red, or blue.

In combination with the first aspect and the foregoing implementation manners, in another implementation manner of the first aspect, the grayscale value of the color of the light signal corresponding to the point with the largest grayscale value in the target spot is equal to 255, and the grayscale The point with the largest value is located in the second area.

With reference to the first aspect and the foregoing implementation manners, in another implementation manner of the first aspect, the target light spot is a mixed light spot including at least two colors of green, red, and blue.

Combining the first aspect and the foregoing implementation manners thereof, in another implementation manner of the first aspect, the gray value of the color of the light signal corresponding to the point with the smallest gray value in the target spot is equal to 255, and the gray The point with the smallest value is located in the first area.

In combination with the first aspect and the foregoing implementation manners, in another implementation manner of the first aspect, the method further includes: adjusting the first light according to the peak-to-peak values of different points in the fingerprint image corresponding to the fingerprint data. The gray value of the three primary colors of RGB of the signal and the gray value of the three primary colors of RGB of the second optical signal.

Therefore, the method for fingerprint recognition in the embodiments of the present application can modify the shape of the lens, or modify the distribution of gray values in the light spot, that is, modify the color light weight distribution of the four corners of the fingerprint image, so that the contrast of the four corners is Tend to be consistent, thereby increasing the fingerprint recognition area in different environments such as normal temperature and low temperature, thereby improving fingerprint recognition efficiency.

In a second aspect, a fingerprint identification device is provided, including: a light source for emitting a target light signal to illuminate the finger when the finger presses the fingerprint detection area of the display screen of the terminal device, wherein the target light signal is The target light spot formed by the fingerprint detection area includes a first area and a second area, and the target light signal includes a first light signal corresponding to the first area and a second light signal corresponding to the second area, so The gray values of the three primary colors of red, green, and blue of the first optical signal and the gray values of the three primary colors of RGB of the second optical signal are not equal, and the first area and the second area do not completely overlap; optical The sensor is configured to detect a reflected light signal formed by reflection after the target light signal irradiates the finger, and the reflected light signal is used to obtain fingerprint data of the finger.

With reference to the second aspect, in an implementation manner of the second aspect, the shape of the target spot is a circle.

Combining the second aspect and the foregoing implementation manners thereof, in another implementation manner of the second aspect, the shape of the first region is an axisymmetric strip shape, and the axis of symmetry in the long axis direction of the first region is the first A straight line, the first straight line passes through the center point of the target light spot, the second area is an area of the target light spot other than the first area, the RGB three primary colors of the first light signal The gray value of is smaller than the gray value of the RGB three primary colors of the second light signal.

Combining the second aspect and the foregoing implementation manners thereof, in another implementation manner of the second aspect, a straight line passing through the center point of the target spot and perpendicular to the first straight line is a second straight line, and the target spot Any two points located on the second straight line are the first point and the second point, and the distance from the first point to the center point of the target spot is smaller than the second point to the center point of the target spot The gray value of the color of the light signal corresponding to the first point is smaller than the gray value of the color of the light signal corresponding to the second point.

In combination with the second aspect and the foregoing implementation manners of the second aspect, in another implementation manner of the second aspect, the gray value of the color of the light signal corresponding to the point on the second straight line in the target spot has a parabolic distribution Or elliptical distribution.

With reference to the second aspect and the foregoing implementation manners thereof, in another implementation manner of the second aspect, the angle from the first straight line to the horizontal line is an acute angle.

In combination with the second aspect and the foregoing implementation manners, in another implementation manner of the second aspect, the angle between the first straight line and the horizontal line is equal to 45°.

In combination with the second aspect and the foregoing implementation manners, in another implementation manner of the second aspect, the target light spot is a pure color light spot.

With reference to the second aspect and the foregoing implementation manners, in another implementation manner of the second aspect, the target light spot is green, red, or blue.

In combination with the second aspect and the foregoing implementation manners of the second aspect, in another implementation manner of the second aspect, the gray value of the color of the light signal corresponding to the point with the largest gray value in the target spot is equal to 255, and the gray The point with the largest value is located in the second area.

In combination with the second aspect and the foregoing implementation manners thereof, in another implementation manner of the second aspect, the target light spot is a mixed light spot including at least two colors of green, red, and blue.

In combination with the second aspect and the foregoing implementation manners, in another implementation manner of the second aspect, the gray value of the color of the light signal corresponding to the point with the smallest gray value in the target spot is equal to 255, and the gray The point with the smallest value is located in the first area.

With reference to the second aspect and the foregoing implementation manners, in another implementation manner of the second aspect, the fingerprint data is used to adjust the gray value of the RGB three primary colors of the first optical signal and the second optical signal The gray value of the three primary colors of RGB.

With reference to the second aspect and the foregoing implementation manners, in another implementation manner of the second aspect, the light source is a self-luminous display unit of the display screen in the fingerprint detection area.

In combination with the second aspect and the foregoing implementation manners, in another implementation manner of the second aspect, the light source is disposed below the display screen.

In combination with the second aspect and the foregoing implementation manners of the second aspect, in another implementation manner of the second aspect, the fingerprint identification device further includes: a lens assembly located above the optical sensor for guiding the reflected light signal Or converge to the optical sensor.

With reference to the second aspect and the foregoing implementation manners, in another implementation manner of the second aspect, the shape of the lens assembly is an ellipse.

In combination with the second aspect and the foregoing implementation manners of the second aspect, in another implementation manner of the second aspect, the angle between the straight line at which the two focal points of the ellipse are located and the horizontal line is an acute angle.

With reference to the second aspect and the foregoing implementation manners of the second aspect, in another implementation manner of the second aspect, the angle from the horizontal line to the straight line at which the two focal points of the ellipse are located is an acute angle.

Therefore, the fingerprint identification device of the embodiment of the present application can modify the shape of the lens, or modify the distribution of gray values in the light spot, that is, modify the color light weight distribution of the four corners of the fingerprint image, so that the contrast of the four corners tends to be consistent. , Thereby increasing the fingerprint recognition area in different environments such as normal temperature and low temperature, thereby improving the efficiency of fingerprint recognition.

In a third aspect, a fingerprint identification device is provided, including: a lens assembly and an optical sensor, the lens assembly is located above the optical sensor, and the lens assembly is used to guide or converge the reflected light signal to the An optical sensor, the reflected light signal is formed by reflection of light emitted by a light source after irradiating a finger, and the shape of the imaging area of the lens assembly is an ellipse; the optical sensor is used for detecting the reflection passing through the lens assembly An optical signal, and the reflected optical signal is used to obtain fingerprint data of the finger.

With reference to the third aspect, in an implementation of the third aspect, the angle between the straight line at which the two focal points of the ellipse are located and the horizontal line is an acute angle.

With reference to the third aspect and the foregoing implementation manners of the third aspect, in another implementation manner of the third aspect, the angle from the horizontal line to the straight line at which the two focal points of the ellipse are located is an acute angle.

In combination with the third aspect and the foregoing implementation manners, in another implementation manner of the third aspect, the angle from the horizontal line to the straight line at which the two focal points of the ellipse are located is equal to 45°.

With reference to the third aspect and the foregoing implementation manners, in another implementation manner of the third aspect, the lens assembly is a rotating structure.

With reference to the third aspect and the foregoing implementation manners of the third aspect, in another implementation manner of the third aspect, the rotation center of the rotary structure is the center point of the lens assembly.

Therefore, the fingerprint identification device of the embodiment of the present application can modify the shape of the lens so that the contrast of the four corners tends to be consistent, thereby increasing the fingerprint identification area in different environments such as normal temperature and low temperature, thereby improving fingerprint identification efficiency.

In a fourth aspect, a chip is provided. The chip includes an input and output interface, at least one processor, at least one memory, and a bus. The at least one memory is used to store instructions, and the at least one processor is used to call Instructions to execute the method in the first aspect or any possible implementation of the first aspect.

In a fifth aspect, a terminal device is provided, including the chip as in the fourth aspect.

In a sixth aspect, a computer-readable medium is provided for storing a computer program, and the computer program includes instructions for executing the foregoing first aspect or any possible implementation of the first aspect.

In a seventh aspect, there is provided a terminal device, including: a display screen and a fingerprint identification device arranged below the display screen, wherein the fingerprint identification device is any one of the above second to third aspects or The fingerprint identification device of any one of its various implementations.

In an eighth aspect, a computer program product including instructions is provided. When the computer runs the instructions of the computer program product, the computer executes the first aspect or any one of the possible implementations of the first aspect. Fingerprint identification method. Specifically, the computer program product may run on the terminal device in the fifth aspect or the seventh aspect.

Description of the drawings

Fig. 1A is a schematic diagram of a fingerprint image recognition area under a normal temperature environment.

FIG. 1B is a schematic diagram of the fingerprint image recognition area in a low temperature environment.

Fig. 2A is a directional view of a terminal device according to an embodiment of the present application.

Fig. 2B is a schematic diagram of a partial cross-sectional structure of the terminal device shown in Fig. 2A along A-A'.

Figure 3 is a schematic diagram of a target spot.

Fig. 4 is a schematic diagram of the system structure of a fingerprint identification device according to an embodiment of the present application.

Fig. 5 is a schematic diagram of the system structure of a fingerprint identification device according to another embodiment of the present application.

Fig. 6A is a schematic diagram of a circular lens assembly.

Fig. 6B is a schematic diagram of an oval lens assembly.

Fig. 7 is a schematic diagram of a modified target light spot according to an embodiment of the present application.

Fig. 8 is a schematic diagram of another modified target spot according to an embodiment of the present application.

Fig. 9 is a schematic diagram of superimposing fingerprint images obtained by using pure color light spots.

Fig. 10A is an overlay image of a fingerprint image obtained by using a pure color spot.

Fig. 10B is a fingerprint image overlay obtained by using the fingerprint identification device of the embodiment of the present application.

11A, 11B, and 11C are fingerprint images obtained when light spots with different gray value distributions are used in a normal temperature environment.

12A, 12B, and 12C are fingerprint images obtained when light spots with different gray value distributions are used in a low temperature environment.

FIG. 13 is a schematic flowchart of a method for fingerprint identification according to an embodiment of the present application.

Detailed ways

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

As a common application scenario, the optical fingerprint system provided in the embodiments of this application can be applied to smart phones, tablet computers, and other mobile terminals with display screens or other terminal devices; more specifically, in the above-mentioned terminal devices, fingerprint identification The device may specifically be an optical fingerprint device, which may be arranged in a partial area or an entire area under the display screen, thereby forming an under-display optical fingerprint system.

2A and 2B show schematic diagrams of terminal devices to which the embodiments of the present application can be applied. Among them, FIG. 2A is a front schematic diagram of the terminal device 10, and FIG. 2B is the terminal device 10 shown in FIG. 2A along A'-A'. Partial sectional structure diagram.

As shown in FIGS. 2A and 2B, the terminal device 10 includes a display screen 120 and an optical fingerprint device 130, wherein the optical fingerprint device 130 is disposed in a partial area under the display screen 120. The optical fingerprint device 130 includes an optical sensor, and the optical sensor includes a sensing array with a plurality of optical sensing units, and the area where the sensing array is located or the sensing area thereof is the fingerprint detection area 103 of the optical fingerprint device 130. As shown in FIG. 2A, the fingerprint detection area 103 is located in the display area of the display screen 120. In an alternative embodiment, the optical fingerprint device 130 can also be arranged in other positions, such as the side of the display screen 120 or the non-transmissive area at the edge of the terminal device 10, and the optical fingerprint device 130 can be designed to prevent At least part of the optical signal of the display area is guided to the optical fingerprint device 130, so that the fingerprint detection area 103 is actually located in the display area of the display screen 120.

It should be understood that the area of the fingerprint detection area 103 may be different from the area of the sensing array of the optical fingerprint device 130. For example, through the optical path design of lens imaging, the reflective folding optical path design, or other optical path design such as light convergence or reflection, it can make The area of the fingerprint detection area 103 of the optical fingerprint device 130 is larger than the area of the sensing array of the optical fingerprint device 130.

Therefore, when the user needs to unlock the terminal device or perform other fingerprint verification, he only needs to press his finger on the fingerprint detection area 103 located in the display screen 120 to realize fingerprint input. Since fingerprint detection can be implemented in the screen, the terminal device 10 adopting the above structure does not need to reserve space on its front to set fingerprint buttons (such as the Home button), so that a full-screen solution can be adopted, that is, the display area of the display screen 120 can be It basically extends to the front of the entire terminal device 10.

As an optional implementation, as shown in FIG. 2B, the optical fingerprint device 130 includes a light detecting portion 134 and an optical component 132, and the light detecting portion 134 includes the sensing array and a reader electrically connected to the sensing array. Circuits and other auxiliary circuits, which can be fabricated on a chip (Die) by a semiconductor process, such as an optical imaging chip or an optical sensor. The sensing array is specifically a photodetector array, which includes a plurality of arrays distributed The optical detector can be used as the above-mentioned optical sensing unit; the optical component 132 can be arranged above the sensing array of the light detecting part 134, which can specifically include a filter layer and a light guide layer Or light path guide structure and other optical elements, the filter layer can be used to filter the ambient light penetrating the finger, and the light guide layer or light path guide structure is mainly used to guide the reflected light reflected from the finger surface to the sensor The array performs optical inspection.

In terms of specific implementation, the optical component 132 and the light detecting part 134 may be packaged in the same optical fingerprint component. For example, the optical component 132 and the optical detection part 134 can be packaged in the same optical fingerprint chip, or the optical component 132 can be arranged outside the chip where the optical detection part 134 is located, for example, the optical component 132 can be attached to the Above the chip, or part of the components of the optical assembly 132 are integrated in the above chip.

Among them, the light guide layer or light path guide structure of the optical component 132 has multiple implementation solutions. For example, the light guide layer or light path guide structure may be an optical lens (Lens) layer, which has one or more lens units, such as one or A lens group composed of a plurality of aspheric lenses, which is used to converge the reflected light reflected from the finger to the sensing array of the light detection part 134 below it, so that the sensing array can perform imaging based on the reflected light, thereby obtaining the finger Fingerprint image. Optionally, the optical lens layer may further have a pinhole formed in the optical path of the lens unit, and the pinhole may cooperate with the optical lens layer to expand the field of view of the optical fingerprint device, so as to improve the fingerprint imaging of the optical fingerprint device 130 effect.

In other embodiments, the light guide layer or the light path guide structure may also specifically adopt a micro-lens (Micro-Lens) layer. The micro-lens layer has a micro-lens array formed by a plurality of micro-lens, which may be formed by a semiconductor growth process or Other processes are formed above the sensing array of the light detection part 134, and each microlens can correspond to one of the sensing units of the sensing array. In addition, other optical film layers may be formed between the microlens layer and the sensing unit, such as a dielectric layer or a passivation layer. More specifically, a barrier with microholes may also be formed between the microlens layer and the sensing unit. Optical layer, wherein the micro-hole is formed between the corresponding micro lens and the sensing unit, the light blocking layer can block the optical interference between the adjacent micro lens and the sensing unit, and allow the light corresponding to the sensing unit to pass through the The micro lens is converged into the micro hole and is transmitted to the sensing unit through the micro hole to perform optical fingerprint imaging.

As an optional embodiment, the display screen 120 may be a display screen with a self-luminous display unit, such as an OLED display screen or a micro-LED (Micro-LED) display screen. Taking an OLED display screen as an example, the optical fingerprint device 130 can use the display unit (ie, an OLED light source) of the OLED display screen 120 located in the fingerprint detection area 103 as an excitation light source for optical fingerprint detection. When a finger is pressed on the fingerprint detection area 103, the display screen 120 emits a beam of light to the target finger above the fingerprint detection area 103, and the light is reflected on the surface of the finger to form reflected light or scattered inside the finger to form scattered light In related patent applications, for ease of description, the above-mentioned reflected light and scattered light are collectively referred to as reflected light. Because the ridge and valley of the fingerprint have different light reflection capabilities, the reflected light from the fingerprint ridge and the emitted light from the fingerprint ridge have different light intensities. After the reflected light passes through the optical components, it is optically fingerprinted. The sensing array in the device 130 receives and converts it into a corresponding electrical signal, that is, a fingerprint detection signal; based on the fingerprint detection signal, fingerprint image data can be obtained, and fingerprint matching verification can be further performed, thereby implementing an optical fingerprint in the terminal device 10 Recognition function.

In other embodiments, the optical fingerprint device 130 may also use a built-in light source or an external light source to provide an optical signal for fingerprint detection. In this case, the optical fingerprint device 130 may be suitable for non-self-luminous display screens, such as liquid crystal display screens or other passively-luminous display screens. Taking a liquid crystal display with a backlight module and a liquid crystal panel as an example, in order to support the under-screen fingerprint detection of the liquid crystal display, the edge area under the protective cover of the terminal device 10, and the optical fingerprint device 130 can be provided with a liquid crystal Under the edge area of the panel or the protective cover and guided by the light path so that the fingerprint detection light can reach the optical fingerprint device 130; or, the optical fingerprint device 130 can also be arranged under the backlight module, and the backlight module passes through the The film layers such as the diffusion sheet, the brightness enhancement sheet, and the reflection sheet are provided with holes or other optical designs to allow the fingerprint detection light to pass through the liquid crystal panel and the backlight module and reach the optical fingerprint device 130. When the optical fingerprint device 130 adopts a built-in light source or an external light source to provide an optical signal for fingerprint detection, the detection principle is the same as that described above.

It should be understood that, in specific implementation, the terminal device 10 further includes a transparent protective cover plate, which may be a glass cover plate or a sapphire cover plate, which is located above the display screen 120 and covers the front surface of the terminal device 10 . Because, in the embodiment of the present application, the so-called finger pressing on the display screen 120 actually refers to pressing on the cover plate above the display screen 120 or covering the surface of the protective layer of the cover plate.

On the other hand, in some embodiments, the optical fingerprint device 130 may include only one optical sensor. At this time, the fingerprint detection area 103 of the optical fingerprint device 130 has a small area and a fixed position. Therefore, the user needs to perform fingerprint input Press the finger to a specific position of the fingerprint detection area 103, otherwise the optical fingerprint device 130 may not be able to collect fingerprint images, resulting in poor user experience. In other alternative embodiments, the optical fingerprint device 130 may specifically include multiple optical sensors; the multiple optical sensors may be arranged side by side under the display screen 120 by splicing, and the sensing areas of the multiple optical sensors jointly constitute The fingerprint detection area 103 of the optical fingerprint device 130. In other words, the fingerprint detection area 103 of the optical fingerprint device 130 may include multiple sub-areas, and each sub-area corresponds to the sensing area of one of the optical sensors, so that the fingerprint collection area 103 of the optical fingerprint device 130 can be expanded to The main area of the lower half of the display screen is extended to the area where the finger is habitually pressed, so as to realize the blind fingerprint input operation. Alternatively, when the number of optical sensors is sufficient, the fingerprint detection area 103 can also be extended to half of the display area or even the entire display area, thereby realizing half-screen or full-screen fingerprint detection.

Generally, regardless of whether the optical fingerprint device 130 uses the self-luminous display unit of the display screen 120 or an external light source as the excitation light source for fingerprint detection, the light signal for fingerprint detection emitted by the excitation light source forms a circular light spot in the fingerprint detection area 103, for example The light signal is usually a pure-color light signal, correspondingly formed as a pure-color light spot (pattern), for example, a circular white light spot as shown in FIG. 3, or a light spot of other colors, such as a green light spot.

In the case of using such a round pure color spot, affected by the OLED stack, the imaging of the optical fingerprint under the screen in a normal temperature environment will be an elliptical spot. For example, as shown in Figure 1A, the effective recognition area of the fingerprint image accounts for Less than 50%, and basically located in the middle of the image, where the signals at the lower left and upper right corners of the image are much weaker than the other two diagonal corners. However, in a low temperature environment, due to changes in the characteristics of the finger, the middle of the fingerprint image will become blurred and the overall contrast will decrease. For example, as shown in FIG. 1B, the effective recognition area of the fingerprint image will eventually decrease sharply, which seriously affects the recognition rate of the fingerprint.

Therefore, the embodiments of the present application propose a fingerprint identification device and a method for fingerprint identification. By modifying the shape of the lens assembly or modifying the color light weight distribution of the four diagonal corners of the light spot, the contrast of the four corners tends to be Consistent, thereby increasing the recognition area of normal and low temperature, thereby increasing the recognition rate.

Specifically, FIG. 4 and FIG. 5 are schematic diagrams of the system structure of the fingerprint identification device 300 provided by an embodiment of the present application. As shown in FIG. 4 and FIG. 5, the fingerprint identification device 300 may be disposed under the display screen 200 of the terminal device. In the embodiment of the present application, the display screen 200 may correspond to the display screen 120 shown in FIGS. 2A and 2B, and the fingerprint detection area 210 of the display screen 200 may be the fingerprint detection area 103 shown in FIG. 2A.

Optionally, the fingerprint identification device 300 may include a light source 310, and the light source 310 may be used to emit a target light signal to the fingerprint detection area 210, and the target light signal may form a target light spot 311 in the fingerprint detection area 210.

For example, in the embodiment shown in FIG. 4, it is assumed that the display screen 200 is a self-luminous display (such as an OLED display), and it includes a plurality of self-luminous display units (such as OLED pixels or an OLED light source). The display unit is configured to emit light under the driving of the display driving module to make the display screen 200 display a corresponding screen. In the display screen 200, a self-luminous display unit located in a corresponding part of the fingerprint detection area 210 can be used as a light source 310 for the fingerprint identification device 300 to perform fingerprint detection.

For another example, in the embodiment shown in FIG. 5, the light source 310 of the fingerprint identification device 300 for fingerprint detection may also be an external light source 310 additionally provided in the fingerprint identification device 300, as shown in FIG. The set light source 310 may be arranged under the display screen 200 for emitting target light signals to the fingerprint detection area 210 of the display screen 200.

For ease of description, the light source 310 in the embodiment of the present application may refer to the arrangement of the light source shown in FIG. 4 or FIG. 5.

Optionally, the fingerprint identification device 300 may further include: an optical sensor 320 for receiving a reflected light signal formed by reflecting the target light signal on the surface of a target object (such as a user's finger) in the fingerprint detection area 210, where The reflected light signal can be used as a fingerprint detection signal to obtain fingerprint data and determine the user's fingerprint information (for example, fingerprint image) for subsequent fingerprint identification.

Wherein, the optical sensor 320 may correspond to the optical fingerprint chip of the light detecting part 134 in FIG. 2B, which will not be repeated here.

Optionally, the fingerprint identification device 300 may further include an optical component 330, which may converge or guide the reflected light signal passing through the display screen 200 to the optical sensor 320, and the optical component 330 may correspond to that shown in FIG. 2B The optical component 132 will not be repeated here. For example, in the embodiment shown in FIG. 4 or FIG. 5, the optical component 330 may be a lens component, or may also be an optical collimator, and the embodiment of the present application is not limited thereto.

The following will take FIGS. 4 and 5 as an example to describe in combination with specific embodiments that by modifying the shape of the lens assembly or modifying the color light weight distribution of the four diagonal corners of the light spot, the contrast of the four corners tends to be consistent. Thereby increasing the recognition area of normal and low temperature, and thus the recognition rate.

Optionally, as a first embodiment, the recognition rate can be improved by modifying the shape of the lens assembly.

Specifically, taking FIGS. 4 and 5 as an example, the optical component 330 may be a lens component 330, and the lens component 330 is located above the optical sensor for guiding or converging the reflected light signal to the optical sensor. The reflected light signal is formed by the light emitted by the light source irradiating the finger and reflecting, wherein the shape of the lens assembly is elliptical, so that the imaging area of the lens assembly is elliptical; the optical sensor 320 is used to detect the light passing through the lens assembly 330 The reflected light signal is used to obtain fingerprint data of the finger.

It should be understood that the elliptical shape of the lens assembly in the embodiments of the present application refers to: by modifying the optical surface of the optical lens included in the lens assembly, the optical imaging of the lens assembly is elliptical distortion, so that the optical imaging area is elliptical. .

Specifically, the lens assembly 330 may include one or more lenses, and the lens may be a meniscus lens or a micro lens. For example, the lens assembly 330 may be an optical lens (Lens) layer, which has one or more lens units, such as a lens group consisting of one or more aspheric lenses; for another example, the lens assembly 330 may also specifically adopt micro lenses (Micro-Lens) layer, the micro lens layer has a micro lens array formed by a plurality of micro lenses.

If the lens assembly 330 includes only one lens, the oval shape of the lens assembly 330 may indicate that the shape of the optical surface of the one lens is an oval, so that the shape of the imaging area of the lens assembly 330 is an oval. If the lens assembly 330 includes a plurality of lenses, the oval shape of the lens assembly 330 may mean that at least one lens in the lens assembly 330 is oval, so that the shape of the imaging area of the lens assembly 330 is an oval. For the convenience of description, the related description about the lens assembly 330 being elliptical in this application indicates that any lens in the lens assembly 330 may be elliptical.

FIG. 6A shows a schematic diagram of a conventional lens assembly, and FIG. 6B shows a schematic diagram of a lens assembly according to an embodiment of the present application. As shown in FIG. 6A, for the circular lens commonly used at present, the imaging area is the circle shown by the black curve in FIG. 6A. Correspondingly, a circular light spot, that is, the gray circular area in FIG. 6A, can be used, for example, a pure color circular light spot. The fingerprint image acquired corresponding to FIG. 6A can be as shown in FIG. 1A and FIG. 1B, and the signals of the two image corners at the bottom left and top right are much weaker than the other two diagonal corners. Therefore, an elliptical lens as shown in FIG. 6B can be used, that is, the imaging area is an ellipse as shown by the black curve in FIG. 6B. Correspondingly, a circular light spot, that is, the gray circular area in FIG. 6B, is similar to the light spot shown in FIG. 6A, and a pure color circular light spot can still be used. Fig. 6B enables the modified lens assembly 330 to stretch and shrink the image, and to ensure that the fingerprint is clearer through distortion, the fingerprint information can fill the entire optical sensor 320, and the modulation transfer function of the four corners (Modulation Transfer Function, MTF) value to make it converge.

Specifically, the shape of the lens assembly 330 can be adjusted according to the MTF of the four corners of the fingerprint image and the MTF of the middle position, so that the shape of the lens assembly 330 is elliptical or approximately elliptical. For example, the shape of the lens assembly 330 can be determined according to the peak-to-peak values of different points in the acquired fingerprint image. Taking the fingerprint images shown in FIGS. 1A and 1B as an example, the peak-to-peak values of the lower left and upper right image corners are relatively small, so the shape of the lens assembly 330 can be set as an elliptical lens as shown in FIG. 6B. Or, for the reverse example of the fingerprint images shown in FIG. 1A and FIG. 1B, that is, when the peak-to-peak values of the lower left and upper right image corners are large, the direction of the ellipse of the lens assembly 330 can be set as shown in FIG. 6B The opposite of the elliptical lens, and the embodiment of the present application is not limited to this.

The setting direction of the ellipse of the lens assembly 330 can be set according to actual applications, so as to maximize the recognition area of the fingerprint image. Optionally, the direction may be set such that the angle between the straight line L where the two focal points of the ellipse of the lens assembly 330 are located and the horizontal line L0 may be an acute angle or a right angle.

For example, taking FIGS. 1A and 1B as an example, since the signals at the lower left and upper right image corners are much weaker than the other two diagonal corners, the lens assembly 330 can be set to a direction such as 6B, that is, the direction of the lens assembly 330 The ellipse satisfies: the angle from the horizontal line L0 to the line L where the two focal points of the ellipse are located is an acute angle, where the angle from the horizontal line L0 to the line L where the two focal points of the ellipse are located represents: the horizontal line L0 surrounds it The intersection point with the straight line L where the two focal points of the ellipse is located is rotated counterclockwise to the angle passed when it overlaps the straight line L where the two focal points of the ellipse are located. For example, the angle from the horizontal line L0 to the straight line L where the two focal points of the ellipse are located may be equal to 45°.

Optionally, if the lens assembly 330 includes multiple lenses, the directions of the ellipses of different lenses may be set to be the same or different.

Optionally, the lens assembly 330 may be a rotating structure. For example, the lens assembly 330 may rotate around its center point, so that the direction of the ellipse of the lens assembly 330 can be adjusted arbitrarily according to actual applications.

Therefore, the lens assembly of the embodiment of the present application is set in an elliptical shape, so that the fingerprint information covers the entire optical sensor, and at the same time, the MTF of the four corners of the lens is increased to make it uniform.

Optionally, as a second embodiment, the distribution of the gray value of the light spot can be modified to further increase the fingerprint recognition area.

Specifically, taking FIGS. 4 and 5 as an example, when a finger presses the fingerprint detection area 210 of the display screen of the terminal device, the target light signal emitted by the light source 310 will illuminate the finger and form a reflected light signal. In the reflection, the target light spot 311 formed by the target light signal in the fingerprint detection area 210 may include a first area and a second area, the first area and the second area may be any two areas of the target light spot, and The first area and the second area do not completely overlap; the target light signal includes a first light signal corresponding to the first area and a second light signal corresponding to the second area, the red and green of the first light signal The gray values of the three primary colors of blue, RGB, and the gray values of the three primary colors of RGB of the second light signal are not equal.

Optionally, in the embodiment of the present application, taking the self-luminous display unit of the display screen 200 shown in FIG. 4 as the light source 310 of the fingerprint identification device 330 as an example, the display drive module can be used to drive the display screen 200 in The ratio and/or gray value of the three primary colors of RGB in the target light signal emitted by the self-luminous display unit of the fingerprint detection area 210. Similarly, taking the external light source 310 shown in FIG. 5 as an example, the RGB in the target light signal emitted by the light source 310 can be driven by the chip in the fingerprint recognition device 300 or the processor in the terminal device where the fingerprint recognition device 300 is located. The ratio and/or gray value of the three primary colors.

Specifically, the target light spot 311 may have any shape. Generally, the target light spot 311 is circular. For example, the target light spot may be a circular light spot as shown in FIG. 3. For ease of description, the embodiment of the present application takes a circular target spot 311 as an example for description.

In the embodiment of the present application, the color of the target light spot 311 is related to the color of the corresponding target light signal. For ease of description, the color of the target light spot 311 described in the embodiment of the present application may correspond to the color of the target light signal, for example, The gray value of the color at different positions of the target light spot 311 can be achieved by adjusting the gray value of the color of the corresponding light signal in the target light signal.

It should be understood that, as shown in FIG. 3, the existing light spot usually adopts a pure color light spot, such as green, red or blue, and the gray value of different positions of the light spot is usually set to a maximum value of 255. At this time, the corresponding obtained is shown in FIG. 1A. The fingerprint image shown in Figure 1B will have the problem of inconsistency in the MTF of the four corners, which will cause the fingerprint recognition area to be limited. Therefore, in order to increase the fingerprint image recognition area, it can be based on the distribution of the fingerprint image, for example, according to the fingerprint image. The size of the peak-to-peak value at the position can be adjusted to the gray value at different positions of the target light spot 311. For example, for any incompletely overlapping first area and second area in the target light spot 311, the gray value of the first area The value may be different from the gray value of the second region, that is, the gray value of the three primary colors of RGB of the first light signal and the gray value of the three primary colors of RGB of the second light signal are not equal.

Considering that the existing light spots with uniform gray values will cause the MTF of the four corners of the fingerprint image to be inconsistent, the distribution of gray values at the four corners of the light spots can be modified. Specifically, the first area and the second area in the embodiment of the present application may refer to any two incompletely overlapping areas on the light spot. However, if you consider the distribution of the above gray values, in order to make the gray value contrast between the first area and the second area more obvious, consider dividing the first area and the second area according to the size of the gray value, that is, the fingerprint image The area with better signal is set as the first area, and the other areas with poor signal are set as the second area. In this way, the sharpness of the fingerprint image can be changed by modifying the gray value of the first area or the second area.

Specifically, since usually the two diagonals and the central part of the fingerprint image are effective, the first area is set as an axially symmetrical stripe area (or can also be called a band-shaped area) on the light spot. The axis of symmetry in the long axis direction of a region can be referred to as a first straight line, which passes through the center point of the target spot. For example, taking Fig. 7 as an example, the line with a diameter of the circular spot in Fig. 7 is L1, which is the first straight line, that is, the first area is between the white lines from top left to bottom right in Fig. 7 The axis of symmetry in the long axis direction of the first area S1 is the first straight line L1. The size of the first area S1 can be arbitrarily set according to actual applications, and the embodiment of the present application is not limited to this.

All areas of the light spot other than the first area may be set as the second area. For example, the second area may be all or part of the target light spot except the first area. For example, still taking the light spot shown in FIG. 7 as an example, in addition to the first area S1 described above, the light spot also includes two areas, the upper right corner and the lower left corner. All or part of the two areas may be the second area. Area S2.

In the embodiment of the present application, the gray values of the three primary colors of RGB of the first light signal corresponding to the first area are different from the gray values of the three primary colors of RGB of the second light signal corresponding to the second area. For example, taking the division of the first area S1 and the second area S2 in FIG. 7 as an example, the gray value of the RGB three primary colors of the first optical signal can be set to be smaller than the gray value of the RGB three primary colors of the second optical signal. Degree value.

It should be understood that the above-mentioned FIG. 7 is only an example of dividing the first area and the second area in the light spot, and the first area and the second area may also be divided in other ways. For example, it is also possible to divide the first area and the second area in the opposite direction of FIG. 7, that is, the first area is a strip-shaped area from the upper right corner to the lower left corner, and the part of the light spot except the first area is the second area The embodiments of this application are not limited to this.

In other words, the direction of the first straight line as the axis of symmetry of the first region can be set according to actual applications. For example, taking FIG. 7 as an example, it can be set that the angle from the first straight line L1 to the horizontal line L0 is an acute angle, where the angle from the first straight line L1 to the horizontal line L0 refers to the first straight line L1 around Follow the intersection of the first straight line L1 and the horizontal line L0, and rotate in a counterclockwise direction to the angle that it travels when it overlaps the horizontal line L0.

Optionally, the angle from the first straight line L1 to the horizontal line L0 may be an acute angle of any size, for example, the angle from the first straight line to the horizontal line may be equal to 45°.

The following will take the fingerprint images shown in FIGS. 1A and 1B as an example to describe the method of changing the gray value distribution in the light spot. Specifically, according to Figures 1A and 1B, since the signals at the lower left and upper right corners of the image are much weaker than the other two diagonal corners, the target spot 311 can be reduced except for the lower left and upper right corners. The gray value of the position, for example, reduces the gray value of the upper left and lower right corners and the middle position, or increases the corresponding gray value of the lower left and upper right corners of the target spot 311, thereby increasing the fingerprint recognition area.

For the first method, the fingerprint recognition area can be increased by reducing the gray value of other positions except the lower left and upper right corners of the target spot 311.

Specifically, this method is mainly applied to the case where the target light spot is a pure color light spot, for example, the target light spot is any one of the three primary color light spots, that is, the target light spot is a green, red or blue light spot. Corresponding to Figure 1A and Figure 1B, when a pure color spot is used, and the gray value of each part on the spot is equal, for example, the gray value is 255, then the fingerprint image is obtained as shown in Figure 1A and Figure 1B, in order to increase the lower left Since the gray values of the two image corners and the upper right corners have been greatly maximized, it can be considered to reduce the gray values of other positions in the target spot 311 except for the lower left and upper right corners.

For example, taking FIG. 7 as an example, it is assumed that before adjusting the gray value, the FIG. 7 represents a pure green target spot, and the gray value at each location is the maximum value of 255. Taking into account the fingerprint images shown in FIGS. 1A and 1B, the first area S1 and the second area S2 are divided as shown in FIG. 7, and the gray value of the first area S1 is set lower than the second area S1. Area S2.

Specifically, as shown in Figures 1A and 1B, the signals at the bottom left and top right corners of the fingerprint image are much weaker than the other two diagonal corners, so the top left and bottom right directions with better signals are set to the first In the direction of the straight line L1, the gray value of each point on the first straight line L1 is the area with the smallest gray value on the target light spot. As for the straight line perpendicular to the first straight line L1 and passing through the target spot, it is referred to herein as the second straight line L2, and there are countless second straight lines L2. For any one of the second straight lines L2, the part of the second straight line L2 on the target spot is a line segment of finite length, which includes countless points, and the gray value of each point on this line segment can be set as In a parabolic or elliptical distribution, the gray value of the first area S1 in the target spot is smaller than the gray value of the second area S2, wherein the gray value of each point on the first straight line L1 The area with the smallest gray value on the target spot.

For example, here is a special second straight line L2 as an example, that is, the second straight line L2 passing through the center point of the target spot, that is, the second straight line L2 shown in FIG. 7, and the part of the L2 on the target spot is the target spot. A diameter of is a line segment of finite length. This line segment includes countless points. The gray value of each point on this line segment can be set to a parabolic or elliptical distribution, that is, for any two Points, here called the first point and the second point, if the distance from the first point to the center point of the target spot is less than the distance from the second point to the center point of the target spot, then the first point corresponds to The gray value of the color of the light signal is smaller than the gray value of the color of the light signal corresponding to the second point. By analogy, the gray value of each second straight line L2 perpendicular to the first straight line L1 is set to a parabolic distribution as described above, so that the target spot as shown in Figure 7 can be obtained (or both can be set to Elliptical distribution), the gray value of the first area S1 in the target spot is all smaller than the gray value of the second area S2. Wherein, for the point corresponding to the maximum gray value, such as the point with the gray value equal to 255, it can be set in the second area S2 of the target light spot.

It should be understood that, in FIG. 7, the angle between the first straight line L1 and the horizontal is equal to 45° as an example. Similarly, other angles can also be used to set the gray value. For example, the first straight line L1 may also be set to an angle equal to 30° with the horizontal, or other angles, and the embodiment of the present application is not limited thereto.

In the embodiment of this application, because the gray value of the partial area of the target spot is reduced, in order to obtain the same light intensity, a longer exposure time is required. At this time, the fingerprint image obtained in the lower left and upper right corners The peak-to-peak value will increase due to the increase of the exposure time, thereby achieving the improvement of the overall uniformity of the fingerprint image, and finally achieving the effect of increasing the recognition area.

For the second method, the fingerprint recognition area can be increased by increasing the gray values corresponding to the lower left and upper right corners of the target spot 311.

Different from the second method above, for the existing pure color spot, the gray value of each part of the spot is the same, for example, the gray value is 255, then the fingerprint image is obtained as shown in Figure 1A and Figure 1B, in order to increase the lower left For the signals of the two image corners and the upper right corners, other colors can be considered to increase the gray values of the lower left and upper right corners of the target spot 311.

For example, considering the fingerprint images shown in Figures 1A and 1B as well, taking Figure 8 as an example, the first region S1 and the second region S2 are divided in a similar manner to that of Figure 7. The results of the division are shown in Figure 8, for simplicity , I won’t repeat it here. According to the first area S1 and the second area S2 as shown in FIG. 8, the gray value of the second area S2 can be set higher than the first area S1.

As shown in Figure 1A and Figure 1B, the signals at the lower left and upper right corners of the fingerprint image are much weaker than the other two diagonal corners, so the upper left and lower right directions with better signals are set as the first straight line L1. Direction, the gray value of each point on the first straight line L1 is the area with the smallest gray value on the target spot. It is assumed here that the target light spot shown in FIG. 8 adopts a pure green light spot before adding other color lights to adjust the gray value, and the gray value of each place takes the maximum value of 255. For a straight line perpendicular to the first straight line L1 and passing through the target spot, it is referred to herein as a second straight line L2, and there are countless second straight lines L2. For any one of the second straight lines L2, the part of the second straight line L2 on the target spot is a line segment of finite length. This line segment includes countless points. The color light can be increased, such as adding red light and/ Or blue light, so that the gray value of each point on this line segment can assume a parabolic or elliptical distribution due to the superposition of color and light, where the gray value of each point on the first straight line L1 is the smallest gray value on the target spot For example, the gray value of the first straight line L1 can be set to the gray value of the pure green spot, that is, the gray value is 255, and the gray value of other areas is greater than 255 due to the superposition of other colors. Therefore, the gray value of the second area S2 in the target spot is higher than that of the first area S1.

For example, here is a special second straight line L2 as an example, that is, the second straight line L2 passing through the center point of the target spot, that is, the second straight line L2 shown in FIG. 8, and the part of this L2 on the target spot is the target spot. A diameter of is a line segment of finite length. This line segment includes countless points. The gray value of each point on this line segment can be adjusted by adding other color lights, such as adding red and/or blue light. It is a parabolic or elliptical distribution, that is, for any two points on this diameter, they are called the first point and the second point here. If the distance from the first point to the center point of the target spot is less than the second point From the point to the center point of the target spot, the gray value of the color of the light signal corresponding to the first point is smaller than the gray value of the color of the light signal corresponding to the second point. By analogy, the gray value of each second straight line L2 perpendicular to the first straight line L1 is set to a parabolic distribution as described above, so that the target spot as shown in Figure 8 can be obtained (or both can be set to Elliptical distribution), the gray value of the first area S1 in the target spot is all smaller than the gray value of the second area S2. Among them, for the point corresponding to the maximum gray value, it can be set in the second area S2 of the target spot; and the point corresponding to the minimum gray value, for example, the red and blue gray values are 0, green gray The degree value is equal to 255, which can be set in the first area S1 of the target spot.

It should be understood that, similar to FIG. 7, in FIG. 8, the angle between the first straight line L1 and the horizontal is equal to 45° as an example. Similarly, other angles can also be used to set the gray value. For example, the first straight line L1 may also be set to an angle equal to 30° with the horizontal, or other angles, and the embodiment of the present application is not limited thereto.

Optionally, the light source in the embodiment of the present application can also be set to a rotatable structure, so that the angle of the target spot can also be rotated and adjusted, that is, the minimum gray value of the target spot shown in FIGS. 7 and 8 The position, that is, the direction of the first straight line L1 can be adjusted and rotated.

It should be understood that the two ways of changing the gray value of the light spot in the second embodiment can be used alone or in combination; similarly, the first and second embodiments can be used alone or Used in combination with each other, the embodiments of the present application are not limited thereto.

In the embodiment of the present application, the adjustment of the gray value of the target light spot and the adjustment of the lens shape can both be based on the fingerprint image. For example, by adjusting the gray value of the target light spot, the gray value of the RGB three primary colors of the first light signal and the second light signal can be adjusted according to the peak-to-peak values of different points in the fingerprint image corresponding to the acquired fingerprint data. The gray value of the three primary colors of RGB, for example, the fingerprint image is generated according to the fingerprint data obtained when the light spot of pure color uniform gray value is used, and the RGB three primary colors of the first light signal are adjusted according to the peak-to-peak value of different points in the fingerprint image The gray value and the gray value of the RGB three primary colors of the second light signal.

The following will take a specific embodiment as an example to describe in detail the calculation process of the above-mentioned second embodiment.

Step 1, the light spot irradiated by the light source is a pure green spot, and the exposure time is recorded as t1 after the automatic exposure.

Step 2: Collect the fingerprint image of the pure green spot, and draw a three-dimensional chart (3D chart). As shown in Figure 9, the fingerprint image is superimposed on the vertical and horizontal placement methods to obtain the fingerprint image on the right side of the middle scale in Figure 9.

Step 3. Calculate the peak and valley values corresponding to each point in the fingerprint image on the right side of the middle sign in Fig. 9 and fit an elliptical surface to obtain the fitting function Signal=g ₀ (x ₀ , y ₀ ).

Step 4. Take the value at Signal'=1/2*max(Signal) as the normalized value, then the normalized weight is an elliptic surface, which is also the attenuation coefficient function, set to β(x,y ), that is, Signal'=K*β(x,y), where K=Signal=g ₀ (x ₀ ,y ₀ ).

Step 5. In the same fixed environment, modify the shade gray value, and use a fixed exposure time t1 to collect Signal=g(x,y) respectively; fit the relationship curve between different gray values and Signal Signal=f(g ), the inverse relationship is g=F(Signal).

Step 6. According to the value g=F(Signal)=F(K*β(x,y)) obtained in step 4 and step 5, the gray value change of g on the plane (x,y) is obtained, so The elliptical surface with the gray value change when the green light spot is used is g(x,y).

Step 7, modify the light spots corresponding to the light source to blue and red respectively, repeat steps 1 to 6, to obtain the blue gray value change surface B(x,y) and the red light gray value change surface R(x,y) respectively At this time, three pure-color light spot gray-scale distribution curved surfaces are obtained. That is, the design of mode 1 in the second embodiment described above is completed.

Step 8. According to the three-primary-color curved surface obtained in Step 7, further, any combination can be made while ensuring that the signal of the entire screen is basically the same to obtain an elliptical spot of mixed color, thereby completing the second embodiment above Design in the second way.

After completing the above steps, compare the 3D chart overlays before and after the design. That is, follow the above process until step 8 to obtain the modified fingerprint image, and superimpose the fingerprint image vertically and horizontally to obtain the effect diagram shown in Figure 10B, and the superimposition of step 2 The picture shows Figure 10A (that is, the fingerprint image on the right side of the middle number in Figure 9). Comparing Fig. 10A with Fig. 10B shows that the fingerprint signal of the entire screen corresponding to the light spot is much more uniform, that is, the effective area is much larger.

In addition, in a normal temperature environment, the fingerprint image obtained by using a uniform light spot is shown in Figure 11A; the above steps are used to implement the design of mode one in the second embodiment above, and the fingerprint image is obtained as shown in Figure 11B; the above steps are used to achieve According to the design of the second method in the second embodiment, the fingerprint image obtained is as shown in FIG. 11C. Comparing the three effect diagrams, the order from excellent to poor is: FIG. 11C> FIG. 11B> FIG. 11A, that is, the design of the second embodiment in the second embodiment is the best, and the existing pure color light spot has the worst effect.

Similarly, in a low temperature environment, the fingerprint image obtained by using a uniform light spot is shown in Figure 12A; the above steps are used to implement the design of the second embodiment described above, and the fingerprint image is obtained as shown in Figure 12B; using the above steps The design of mode two in the above second embodiment is implemented, and the fingerprint image obtained is as shown in FIG. 12C. Comparing the three effect diagrams, the order from good to bad is: Fig. 12C> Fig. 12B> Fig. 12A, that is, the design of the second embodiment in the second embodiment is the best, and the existing pure color spot has the worst effect.

Therefore, the fingerprint identification device of the embodiment of the present application can modify the shape of the lens, or modify the distribution of gray values in the light spot, that is, modify the color light weight distribution of the four corners of the fingerprint image, so that the contrast of the four corners tends to Consistent, thereby increasing the fingerprint recognition area in different environments such as normal temperature and low temperature, thereby improving fingerprint recognition efficiency.

Above, the device embodiments of the present application are described in detail with reference to FIGS. 1 to 12, and the method embodiments of the present application are described in detail below with reference to FIG. 13. It should be understood that the method embodiments and the device embodiments correspond to each other, and similar descriptions can be Refer to the device embodiment.

FIG. 13 is a schematic flowchart of a method 400 for fingerprint identification according to an embodiment of the present application. It should be understood that the method 400 can be applied to the above fingerprint identification devices or terminal devices. As shown in FIG. 113, the method 400 may include the following content: S410, when a finger presses the fingerprint detection area of the display screen of the terminal device, detecting the reflected light signal formed by the reflection of the target light signal emitted by the light source after illuminating the finger, where The target light spot formed by the target light signal in the fingerprint detection area includes a first area and a second area, and the target light signal includes a first light signal corresponding to the first area and a second light corresponding to the second area. Signal, the gray value of the three primary colors of RGB of the first optical signal and the gray value of the three primary colors of RGB of the second optical signal are not equal, the first area and the second area are not completely overlapped; S420, according to the reflection Optical signal to obtain fingerprint data of the finger.

Optionally, as an embodiment, the shape of the target spot is a circle.

Optionally, as an embodiment, the shape of the first region is an axisymmetric bar, the axis of symmetry in the long axis direction of the first region is a first straight line, and the first straight line passes through the center of the target spot Point, the second area is an area other than the first area in the target spot, and the gray value of the three primary colors of RGB of the first light signal is smaller than the gray value of the three primary colors of RGB of the second light signal.

Optionally, as an embodiment, a straight line passing through the center point of the target spot and perpendicular to the first straight line is a second straight line, and any two points on the second straight line in the target spot are the first point and The second point, the distance from the first point to the center point of the target spot is less than the distance from the second point to the center point of the target spot, and the gray value of the color of the light signal corresponding to the first point is smaller than the second point The gray value of the color of the light signal corresponding to the point.

Optionally, as an embodiment, the gray value of the color of the light signal corresponding to the point located on the second straight line in the target spot is a parabolic distribution or an elliptical distribution.

Optionally, as an embodiment, the angle from the first straight line to the horizontal line is an acute angle.

Optionally, as an embodiment, the included angle between the first straight line and the horizontal line is equal to 45°.

Optionally, as an embodiment, the target light spot is a pure color light spot.

Optionally, as an embodiment, the target light spot is green, red or blue.

Optionally, as an embodiment, the gray value of the color of the light signal corresponding to the point with the largest gray value in the target spot is equal to 255, and the point with the largest gray value is located in the second region.

Optionally, as an embodiment, the target light spot is a mixed light spot including at least two colors of green, red, and blue.

Optionally, as an embodiment, the gray value of the color of the light signal corresponding to the point with the smallest gray value in the target spot is equal to 255, and the point with the smallest gray value is located in the first area.

Optionally, as an embodiment, the method 400 further includes: adjusting the gray values of the RGB three primary colors of the first optical signal and the second optical signal according to the peak-to-peak values of different points in the fingerprint image corresponding to the fingerprint data The gray value of the three primary colors of RGB.

It should be understood that in the method embodiments of the present application, the size of the sequence numbers of the above-mentioned processes does not mean the order of execution, and the execution order of the processes should be determined by their functions and internal logic, and should not be used as described in the embodiments of the present application. The implementation process constitutes any limitation.

It should be understood that the fingerprint identification device of the embodiment of the present application may further include a processor or a processing module, and the processor or processing module may be an integrated circuit chip with signal processing capability. In the implementation process, the steps of the foregoing method embodiments can be completed by hardware integrated logic circuits in the processor or instructions in the form of software. The aforementioned processor may be a general-purpose processor, a digital signal processor (Digital Signal Processor, DSP), an application specific integrated circuit (ASIC), a ready-made programmable gate array (Field Programmable Gate Array, FPGA) or other Programming logic devices, discrete gates or transistor logic devices, discrete hardware components. The methods, steps, and logical block diagrams disclosed in the embodiments of the present application can be implemented or executed. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor or the like. The steps of the method disclosed in the embodiments of the present application may be directly embodied as being executed and completed by a hardware decoding processor, or executed and completed by a combination of hardware and software modules in the decoding processor. The software module can be located in a mature storage medium in the field such as random access memory, flash memory, read-only memory, programmable read-only memory, or electrically erasable programmable memory, registers. The storage medium is located in the memory, and the processor reads the information in the memory and completes the steps of the above method in combination with its hardware.

It can be understood that the fingerprint identification device of the embodiment of the present application may further include a memory, and the memory may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memory. Among them, the non-volatile memory can be read-only memory (Read-Only Memory, ROM), programmable read-only memory (Programmable ROM, PROM), erasable programmable read-only memory (Erasable PROM, EPROM), and electrically available Erase programmable read-only memory (Electrically EPROM, EEPROM) or flash memory. The volatile memory may be a random access memory (Random Access Memory, RAM), which is used as an external cache. By way of exemplary but not restrictive description, many forms of RAM are available, such as static random access memory (Static RAM, SRAM), dynamic random access memory (Dynamic RAM, DRAM), synchronous dynamic random access memory (Synchronous DRAM, SDRAM), double data rate synchronous dynamic random access memory (Double Data Rate SDRAM, DDR SDRAM), enhanced synchronous dynamic random access memory (Enhanced SDRAM, ESDRAM), synchronous connection dynamic random access memory (Synchlink DRAM, SLDRAM) ) And Direct Rambus RAM (DR RAM). It should be noted that the memories of the systems and methods described herein are intended to include, but are not limited to, these and any other suitable types of memories.

The embodiment of the present application also proposes a computer-readable storage medium that stores one or more programs, and the one or more programs include instructions. When the instructions are included in a portable electronic device that includes multiple application programs When executed, the portable electronic device can be made to execute the method of the embodiment shown in FIG. 13.

The embodiment of the present application also proposes a computer program, which includes instructions. When the computer program is executed by a computer, the computer can execute the method of the embodiment shown in FIG. 13.

An embodiment of the present application also provides a chip that includes an input and output interface, at least one processor, at least one memory, and a bus. The at least one memory is used to store instructions, and the at least one processor is used to call the at least one memory. To execute the method of the embodiment shown in FIG. 13.

A person of ordinary skill in the art may be aware that the units and algorithm steps of the examples described in combination with the embodiments disclosed herein can be implemented by electronic hardware or a combination of computer software and electronic hardware. Whether these functions are executed by hardware or software depends on the specific application and design constraint conditions of the technical solution. Professionals and technicians can use different methods for each specific application to implement the described functions, but such implementation should not be considered beyond the scope of this application.

Those skilled in the art can clearly understand that, for the convenience and conciseness of description, the specific working process of the above-described system, device, and unit can refer to the corresponding process in the foregoing method embodiment, which will not be repeated here.

In the several embodiments provided in this application, it should be understood that the disclosed system, device, and method may be implemented in other ways. For example, the device embodiments described above are only illustrative. For example, the division of the units is only a logical function division, and there may be other divisions in actual implementation, for example, multiple units or components can be combined or It can be integrated into another system, or some features can be ignored or not implemented. In addition, the displayed or discussed mutual coupling or direct coupling or communication connection may be indirect coupling or communication connection through some interfaces, devices or units, and may be in electrical, mechanical or other forms.

The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the objectives of the solutions of the embodiments.

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

If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer readable storage medium. Based on this understanding, the technical solution of this application essentially or the part that contributes to the existing technology or the part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including Several instructions are used to make a computer device (which may be a personal computer, a server, or a network device, etc.) execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage media include: U disk, mobile hard disk, read-only memory (read-only memory, ROM), random access memory (random access memory, RAM), magnetic disk or optical disk and other media that can store program code .

The above are only specific implementations of this application, but the protection scope of this application is not limited to this. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed in this application. Should be covered within the scope of protection of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claims.

Claims

A method for fingerprint identification, characterized in that it comprises:

When a finger presses the fingerprint detection area of the display screen of the terminal device, the target light signal emitted by the light source illuminates the reflected light signal formed by reflecting the finger, wherein the target light signal forms a target in the fingerprint detection area The light spot includes a first area and a second area. The target light signal includes a first light signal corresponding to the first area and a second light signal corresponding to the second area. The gray values of the three primary colors of green and blue, RGB, and the gray values of the three primary colors of RGB of the second light signal are not equal, and the first area and the second area do not completely overlap;

According to the reflected light signal, fingerprint data of the finger is acquired.
The method according to claim 1, wherein the shape of the target light spot is a circle.
The method according to claim 2, wherein the shape of the first region is an axisymmetric strip, the axis of symmetry in the long axis direction of the first region is a first straight line, and the first straight line The line passes through the center point of the target light spot, and the second area is an area of the target light spot excluding the first area,

The gray value of the three primary colors of RGB of the first optical signal is smaller than the gray value of the three primary colors of RGB of the second optical signal.
The method according to claim 3, wherein a straight line passing through the center point of the target spot and perpendicular to the first straight line is a second straight line, and the target spot located on the second straight line Any two points are the first point and the second point,

The distance from the first point to the center point of the target light spot is smaller than the distance from the second point to the center point of the target light spot,

The gray value of the color of the light signal corresponding to the first point is smaller than the gray value of the color of the light signal corresponding to the second point.
The method according to claim 4, wherein the gray value of the color of the light signal corresponding to the point located on the second straight line in the target spot is a parabolic distribution or an elliptical distribution.
The method according to claim 5, wherein the angle from the first straight line to the horizontal line is an acute angle.
The method according to claim 6, wherein the angle between the first straight line and the horizontal line is equal to 45°.
The method according to any one of claims 4 to 7, wherein the target light spot is a pure color light spot.
The method according to claim 8, wherein the target light spot is green, red or blue.
The method according to claim 9, wherein the gray value of the color of the light signal corresponding to the point with the largest gray value in the target spot is equal to 255, and the point with the largest gray value is located in the second area.
The method according to any one of claims 4 to 7, wherein the target light spot is a mixed light spot comprising at least two colors of green, red and blue.
The method according to claim 11, wherein the gray value of the color of the light signal corresponding to the point with the smallest gray value in the target spot is equal to 255, and the point with the smallest gray value is located in the first area.
The method according to any one of claims 1 to 12, wherein the method further comprises:

According to the peak-to-peak values of different points in the fingerprint image corresponding to the fingerprint data, the gray values of the RGB three primary colors of the first optical signal and the gray values of the RGB three primary colors of the second optical signal are adjusted.
A fingerprint identification device, characterized by comprising:

The light source is used to emit a target light signal to illuminate the finger when the finger presses the fingerprint detection area of the display screen of the terminal device, wherein the target light spot formed by the target light signal in the fingerprint detection area includes a first area and a first area In the second area, the target light signal includes a first light signal corresponding to the first area and a second light signal corresponding to the second area, and the first light signal has three primary colors of red, green, blue, and RGB. The degree value is not equal to the gray value of the RGB three primary colors of the second light signal, and the first area and the second area do not completely overlap;

The optical sensor is used to detect the reflected light signal formed by the reflection of the target light signal after irradiating the finger, and the reflected light signal is used to obtain fingerprint data of the finger.
The fingerprint identification device according to claim 14, wherein the shape of the target light spot is a circle.
The fingerprint identification device according to claim 15, wherein the shape of the first area is an axis-symmetrical bar shape, the axis of symmetry in the long axis direction of the first area is a first straight line, and the first area A straight line passing through the center point of the target light spot, and the second area is an area of the target light spot excluding the first area,

The gray value of the three primary colors of RGB of the first optical signal is smaller than the gray value of the three primary colors of RGB of the second optical signal.
The fingerprint identification device according to claim 16, wherein a straight line passing through the center point of the target spot and perpendicular to the first straight line is a second straight line, and the target spot is located in the second straight line Any two points on above are the first point and the second point,

The distance from the first point to the center point of the target light spot is smaller than the distance from the second point to the center point of the target light spot,

The gray value of the color of the light signal corresponding to the first point is smaller than the gray value of the color of the light signal corresponding to the second point.
17. The fingerprint identification device according to claim 17, wherein the gray value of the color of the light signal corresponding to the point on the second straight line in the target spot is a parabolic distribution or an elliptical distribution.
The fingerprint identification device according to claim 18, wherein the angle from the first straight line to the horizontal line is an acute angle.
The fingerprint identification device according to claim 19, wherein the angle between the first straight line and the horizontal line is equal to 45°.
The fingerprint identification device according to any one of claims 17 to 20, wherein the target light spot is a pure color light spot.
The fingerprint identification device of claim 21, wherein the target light spot is green, red or blue.
The fingerprint identification device according to claim 22, wherein the gray value of the color of the light signal corresponding to the point with the largest gray value in the target spot is equal to 255, and the point with the largest gray value is located at the The second area.
The fingerprint identification device according to any one of claims 17 to 20, wherein the target light spot is a mixed light spot comprising at least two colors of green, red and blue.
The fingerprint identification device according to claim 24, wherein the gray value of the color of the light signal corresponding to the point with the smallest gray value in the target spot is equal to 255, and the point with the smallest gray value is located at the The first area.
The fingerprint identification device according to any one of claims 14 to 25, wherein the fingerprint data is used to adjust the gray value of the RGB three primary colors of the first optical signal and the second optical signal. The gray value of the three primary colors of RGB.
The fingerprint identification device according to any one of claims 14 to 26, wherein the light source is a self-luminous display unit of the display screen in the fingerprint detection area.
The fingerprint identification device according to any one of claims 14 to 26, wherein the light source is arranged below the display screen.
The fingerprint identification device according to any one of claims 14 to 28, wherein the fingerprint identification device further comprises:

The lens assembly is located above the optical sensor and is used to guide or converge the reflected light signal to the optical sensor.
The fingerprint identification device of claim 29, wherein the lens assembly has an oval shape.
The fingerprint identification device according to claim 30, wherein the angle between the straight line at which the two focal points of the ellipse are located and the horizontal line is an acute angle.
The fingerprint identification device according to claim 31, wherein the angle from the horizontal line to the straight line where the two focal points of the ellipse are located is an acute angle.
A fingerprint identification device, characterized by comprising: a lens assembly and an optical sensor,

The lens assembly is located above the optical sensor, and the lens assembly is used to guide or condense the reflected light signal to the optical sensor, and the reflected light signal is formed by reflection of light emitted by the light source after irradiating the finger, so The shape of the imaging area of the lens assembly is an ellipse;

The optical sensor is used to detect the reflected light signal passing through the lens assembly, and the reflected light signal is used to obtain fingerprint data of the finger.
The fingerprint identification device according to claim 33, wherein the angle between the straight line at which the two focal points of the ellipse are located and the horizontal line is an acute angle.
The fingerprint identification device according to claim 34, wherein the angle from the horizontal line to the straight line where the two focal points of the ellipse are located is an acute angle.
The fingerprint identification device according to claim 35, wherein the angle from the horizontal line to the line at which the two focal points of the ellipse are located is equal to 45°.
The fingerprint identification device of claim 34, wherein the lens assembly is a rotating structure.
The fingerprint identification device according to claim 37, wherein the rotation center of the rotating structure is the center point of the lens assembly.
A terminal device, characterized by comprising: a display screen and a fingerprint identification device arranged below the display screen, wherein the fingerprint identification device is the fingerprint identification device according to any one of claims 14 to 38 .