CN211319246U

CN211319246U - Fingerprint identification device, backlight unit, liquid crystal display and electronic equipment

Info

Publication number: CN211319246U
Application number: CN202020150150.1U
Authority: CN
Inventors: 刘杨赞; 葛丛; 蔡斐欣; 何毅; 皮波
Original assignee: Shenzhen Goodix Technology Co Ltd
Current assignee: Taishengda Optoelectronics Technology (Hubei) Co.,Ltd.
Priority date: 2019-09-20
Filing date: 2020-01-23
Publication date: 2020-08-21
Anticipated expiration: 2030-01-23
Also published as: CN111837130A; WO2021051737A1; CN211319247U

Abstract

The utility model provides a fingerprint identification device, backlight unit, liquid crystal display and electronic equipment, can promote optical fingerprint identification performance under the LCD screen. Fingerprint identification device is used for setting up fingerprint identification under liquid crystal display's backlight unit below in order to carry out the screen, includes: fingerprint identification module set under backlight moduleThe module comprises a brightening prism film and a compensating prism film, wherein the brightening prism film comprises a first brightening prism film side surface, the compensating prism film comprises a first compensating prism film side surface, and the included angle between the first brightening prism film side surface and the plane where the liquid crystal display screen is located is α₁The included angle between the side surface of the first compensation prism film and the plane where the liquid crystal display screen is located is α₂，35°<α₁≤45°，35°<α₂Not more than 45 degrees; the fingerprint identification module is used for receiving a first fingerprint light signal through first target fingerprint light signal behind brightening prism membrane side and the first compensation prism membrane to carry out fingerprint identification, wherein, first target fingerprint light signal is the same with first fingerprint light signal's direction of propagation.

Description

Fingerprint identification device, backlight unit, liquid crystal display and electronic equipment

This application claims priority from the following applications, the entire contents of which are incorporated by reference in this application: a provisional application with the patent office of U.S. patent application No. 62/903,672 and the name of UNDER-DISPLAY OPTICAL SENSORWITH COMPENSATED LIGHT PATHS AND COMPENSATION PARTS OPTIMIZATION was filed in 2019, 9, 20.s.

Technical Field

The application relates to the technical field of optical fingerprints, and more particularly relates to a fingerprint identification device, a backlight module, a liquid crystal display screen and an electronic device.

Background

With the development of biometric identification technology, the application of the underscreen fingerprint identification technology in portable terminals such as mobile phones is more and more extensive. At present, passive Display screens such as Liquid Crystal Display (LCD) screens provide light sources through a backlight module, and various film structures in the backlight module can seriously interfere with fingerprint optical imaging of a fingerprint identification device, so that commercial blocking of the under-screen fingerprint identification technology based on the LCD Display screen is caused.

Therefore, how to improve the performance of optical fingerprint identification under the LCD screen is a technical problem that needs to be solved urgently in the field.

SUMMERY OF THE UTILITY MODEL

The embodiment of the application provides a fingerprint identification device, backlight unit, liquid crystal display and electronic equipment, can promote optical fingerprint identification performance under the LCD screen.

The fingerprint identification device comprises a fingerprint identification module arranged below a backlight module of a liquid crystal display screen, wherein the backlight module comprises a brightening prism film and a compensating prism film, the compensating prism film is arranged below the brightening prism film in parallel, the compensating prism film faces a liquid crystal panel in the liquid crystal display screen in a back-to-back mode, and faces the liquid crystal panel, the brightening prism film comprises a first brightening prism film side face, the compensating prism film comprises a first compensating prism film side face, and an included angle formed by the first brightening prism film side face and a plane where the liquid crystal display screen is located is α₁The included angle between the side surface of the first compensation prism film and the plane where the liquid crystal display screen is located is α₂，35°<α₁≤45°，35°<α₂Not more than 45 degrees; this fingerprint identification module is used for receiving first fingerprint light signal through this first brightening prism membrane side and the first target fingerprint light signal behind the compensation prism membrane side to carry out fingerprint identification, wherein, this first target fingerprint light signal is the same with the direction of propagation of this first fingerprint light signal, and this first fingerprint light signal is the light signal that finger reflection or scattering returned through liquid crystal display top.

In the scheme of this application, through increasing the compensation prism membrane in backlight unit, compensate and revise the fingerprint light signal of blast prism membrane in through liquid crystal display to solve the problem of liquid crystal display below fingerprint image distortion and visual field loss among the prior art, when can improve liquid crystal display's luminance, can also improve the quality of fingerprint image, satisfy fingerprint identification demand under the liquid crystal display. Meanwhile, the included angle between the side face of the first brightening prism film and the first plane is set, and the included angle between the side face of the first compensating prism film and the first plane is 35-45 degrees, so that the brightness requirement of the liquid crystal display screen can be still met on the premise that the fingerprint identification requirement under the liquid crystal display screen is met.

In one possible implementation, the material of the brightness enhancing prism film and the compensating prism film are the same, the first compensating prism film side is parallel to the first brightness enhancing prism film side, α₁＝α₂。

In one possible implementation, the brightness enhancement prism film further includes a second brightness enhancement prism film side, the compensation prism film further includes a second compensation prism film side, and an included angle between the second brightness enhancement prism film side and a plane where the liquid crystal display screen is located is β₁The included angle between the side surface of the second compensation prism film and the plane where the liquid crystal display screen is located is β₂，β₁≥α₁，β₂≥α₂。

In one possible implementation, β₁＝90°-α₁。

In one possible implementation, α₁And β₁The difference value of (2) is less than or equal to a preset threshold value so as to improve the brightness of the liquid crystal display screen.

In one possible implementation, the second compensating prism film side is not parallel to the second brightness enhancing prism film side, β₁≠β₂(ii) a The second fingerprint optical signal forms non-target fingerprint optical signal after passing through this second brightening prism membrane side and this second compensation prism membrane, and this non-target fingerprint optical signal is different with the propagation direction of this second fingerprint optical signal, and this second fingerprint optical signal is the optical signal that returns through the reflection of finger above liquid crystal display or scattering.

In a possible implementation manner, when the second fingerprint optical signal passes through the brightness enhancement prism film and is transmitted to the side surface of the second compensation prism film, most of the second fingerprint optical signal is reflected by the side surface of the second compensation prism film to form the non-target fingerprint optical signal.

In a possible implementation manner, the angles of the first compensation prism film side and the second compensation prism film side are set so that the non-target fingerprint optical signal passing through the second compensation prism film side cannot be received by the fingerprint identification module, and the target fingerprint optical signal passing through the first compensation prism film side is received by the fingerprint identification module for fingerprint identification.

In one possible implementation, β₂＝90°。

In one possible implementation, the second compensating prism film side is parallel to the second brightness enhancing prism film side, β₁＝β₂(ii) a The second fingerprint optical signal forms a second target fingerprint optical signal after passing through the side face of the second brightening prism film and the second compensation prism film, the propagation directions of the second target fingerprint optical signal and the second fingerprint optical signal are the same, and the second fingerprint optical signal is an optical signal which is reflected or scattered and returned by a finger above the liquid crystal display screen.

In a possible implementation, the second target fingerprint optical signal passing through the second compensation prism film side and the first target fingerprint optical signal passing through the first compensation prism film side are both received by the fingerprint identification module to perform fingerprint identification.

In a possible implementation manner, a light absorbing material is arranged on the side surface of the second compensation prism film and used for absorbing light signals received by the side surface of the second compensation prism film.

In one possible implementation, the number of the compensating prisms in the compensating prism film is equal to the number of the brightness enhancing prisms in the brightness enhancing prism film, and a plurality of compensating prisms in the compensating prism film correspond to a plurality of brightness enhancing prisms in the brightness enhancing prism film one to one; the distance between the ridges of two adjacent compensating prisms in the plurality of compensating prisms is equal to the distance between the ridges of two adjacent brightness enhancing prisms in the plurality of brightness enhancing prisms.

In a possible implementation, the first compensation prism in the compensation prism film corresponds to the first brightness enhancement prism film in the brightness enhancement prism film, the included angle of the projection of the ridge of the first compensation prism and the ridge of the first brightness enhancement prism on the first plane is theta, theta is more than or equal to 0 degree and less than or equal to 20 degrees, and the first plane is a plane parallel to the liquid crystal display screen.

In one possible implementation, a first compensating prism in the compensating prism film corresponds to a first brightness enhancing prism film in the brightness enhancing prism film, and a projection of a ridge of the first compensating prism onto a first plane is located in a projection of a substrate of the first brightness enhancing prism onto the first plane, which is a plane parallel to the liquid crystal display screen.

In one possible implementation, the projection of the ridge of the first compensating prism coincides with the projection of the ridge of the first brightness enhancing prism onto the first plane, and the projection of the substrate of the first compensating prism coincides with the projection of the substrate of the first brightness enhancing prism onto the first plane.

In one possible implementation, the liquid crystal display panel comprises two brightness enhancement prism films and two compensation prism films; the two brightening prism films and the two compensation prism films are arranged below the liquid crystal display screen in parallel and are positioned on different planes; the two compensation prism films are respectively arranged below the two brightness enhancement prism films.

In one possible implementation, the projection of the ridge of one brightness enhancing prism in one of the brightness enhancing prism films to the ridge of one brightness enhancing prism in the other of the brightness enhancing prism films in the first plane is perpendicular to each other; the projection of the ridge of one compensating prism in one compensating prism film in the two compensating prism films and the projection of the ridge of one compensating prism in the other compensating prism film on the first plane are mutually vertical, and the first plane is a plane parallel to the liquid crystal display screen.

In one possible implementation, the distance between each adjacent two of the two brightness enhancing prism films and the two compensating prism films is equal.

In one possible implementation, the fingerprint recognition module includes: the optical assembly is used for receiving the first target fingerprint optical signal and transmitting the first fingerprint optical signal to the optical detection array, and the optical detection array is used for converting the received first target fingerprint optical signal into a fingerprint image signal so as to perform fingerprint identification.

In one possible implementation, the optical assembly includes at least one optical lens, which is a spherical or aspherical lens.

The backlight module is suitable for electronic equipment with a liquid crystal display screen and comprises a brightening prism film and a compensating prism film, wherein the compensating prism film is arranged below the brightening prism film in parallel, the compensating prism film faces away from a liquid crystal panel in the liquid crystal display screen, and the brightening prism film faces towards the liquid crystal panel, the brightening prism film comprises a first brightening prism film side face, the compensating prism film comprises a first compensating prism film side face, and the included angle between the first brightening prism film side face and the plane where the liquid crystal display screen is located is α₁The included angle between the side surface of the first compensation prism film and the plane where the liquid crystal display screen is located is α₂，35°<α₁≤45°，35°<α₂≤45°。

In a possible implementation manner, a first fingerprint optical signal forms a first target fingerprint optical signal after passing through the side surface of the first brightness enhancement prism film and the side surface of the first compensation prism film, and the first target fingerprint optical signal is used for fingerprint identification, wherein the first target fingerprint optical signal and the first fingerprint optical signal have the same propagation direction, and the first fingerprint optical signal is an optical signal returned by finger reflection or scattering above the liquid crystal display screen.

Adopt the backlight unit of this application embodiment, can realize the fingerprint identification function under the liquid crystal display when guaranteeing liquid crystal display luminance.

In one possible implementation, β₁＝90°-α₁。

In one possible implementation, the second compensating prism film side is not parallel to the second brightness enhancing prism film side, β₁≠β₂(ii) a The second fingerprint optical signal forms non-target fingerprint optical signal after passing through this second brightening prism membrane side and this second compensation prism membrane, and this non-target fingerprint optical signal is different with the propagation direction of this second fingerprint optical signal, and this non-target fingerprint optical signal is not used for carrying out fingerprint identification, and this second fingerprint optical signal is the optical signal that returns through the reflection of liquid crystal display top finger or scattering.

In a possible implementation manner, when the second fingerprint optical signal passes through the brightness enhancement prism film and is transmitted to the side of the second compensation prism film, most of the second fingerprint optical signal is reflected by the second compensation prism film to form the non-target fingerprint optical signal.

In one possible implementation, β₂＝90°。

In one possible implementation, the second compensating prism film side is parallel to the second brightness enhancing prism film side, β₁＝β₂(ii) a The second fingerprint optical signal forms second target fingerprint optical signal after brightening prism membrane side and this second compensation prism membrane through this second, and this second target fingerprint optical signal is the same with the propagation direction of this second fingerprint optical signal, and this second target fingerprint optical signal is used for carrying out fingerprint identification, and this second fingerprint optical signal is the optical signal that returns through the reflection of liquid crystal display top finger or scattering.

In one possible implementation, two such brightness enhancing prism films and two such compensating prism films are included; the two brightening prism films and the two compensation prism films are arranged below the liquid crystal display screen in parallel and are positioned on different planes; the two compensation prism films are respectively arranged below the two brightness enhancement prism films.

In a third aspect, an electronic device is provided, including: the liquid crystal display screen and, as in the first aspect or the fingerprint identification device in any implementation manner of the first aspect, wherein the liquid crystal display screen includes a backlight module, and the fingerprint identification device is disposed below the liquid crystal panel.

In one possible implementation, the electronic device further includes: the infrared light source is used for providing infrared excitation light for fingerprint detection of the fingerprint identification device, the infrared excitation light irradiates at least part of the display area of the liquid crystal display screen, and the at least part of the display area at least partially covers the fingerprint detection area of the fingerprint identification device; wherein, infrared excitation light of this infrared light source forms target fingerprint infrared light signal through this backlight unit after the finger reflection or the scattering of this fingerprint detection area top, and this fingerprint identification device is used for receiving this target fingerprint infrared light signal and carries out fingerprint identification.

In one possible implementation, the infrared light source is a single or a plurality of infrared light emitting diodes; the single or multiple infrared light-emitting diodes are distributed around the fingerprint detection area.

In one possible implementation, the infrared light source is disposed below a glass cover plate of the liquid crystal display and is disposed side by side with a liquid crystal panel of the liquid crystal display.

In one possible implementation, the infrared light source is attached obliquely below the glass cover plate.

In one possible implementation, the electronic device further includes: and the infrared light transmission layer is arranged between the infrared light source and the glass cover plate and/or between the infrared light source and the liquid crystal display screen and is used for transmitting the infrared excitation light and blocking visible light.

Through the scheme of this application embodiment, carry out optics fingerprint detection through the target fingerprint infrared light that adopts infrared light source to produce, can reduce the interference of screen visible light to infrared light fingerprint detection, and the optics illuminance of balanced infrared light fingerprint image, further improve the quality of fingerprint formation of image.

In a fourth aspect, there is provided a liquid crystal display panel comprising: such as the backlight module in the second aspect or any possible implementation manner of the second aspect.

In a fifth aspect, an electronic device is provided, comprising: the liquid crystal display panel in the fourth aspect.

Drawings

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

Fig. 2 is a schematic perspective view of a backlight module according to an embodiment of the present application.

FIG. 3 is a schematic diagram of a prismatic film according to an embodiment of the present application.

Fig. 4 is a schematic optical path diagram of a fingerprint identification device under a liquid crystal display screen according to an embodiment of the application when performing fingerprint identification.

Fig. 5 is a schematic diagram of a fingerprint image according to an embodiment of the present application.

FIG. 6 is a schematic diagram of another fingerprint image according to an embodiment of the present application.

Fig. 7 is a schematic structural diagram of a fingerprint identification device according to an embodiment of the present application.

FIG. 8 is a partially enlarged schematic view of a brightness enhancing prism film and a compensating prism film according to embodiments of the present application.

FIG. 9 is a partially enlarged schematic view of another brightness enhancing prism film and a compensating prism film according to an embodiment of the present application.

FIG. 10 is a partially enlarged schematic view of another brightness enhancing prism film and a compensating prism film according to an embodiment of the present application.

FIG. 11 is a cross-sectional view of another compensating prism film and a brightness enhancing prism film according to embodiments of the present application.

Figures 12-14 are three schematic views of the projections of a plurality of prismatic ribs of a compensating triangular prism and a plurality of prismatic ribs of a brightness enhancing triangular prism onto a first plane, according to embodiments of the present application.

Fig. 15 is a schematic perspective view of two prism film sets according to an embodiment of the present disclosure.

Fig. 16 is a schematic cross-sectional view of fig. 15 in the XZ plane.

Fig. 17 to 18 are schematic cross-sectional views of two prism film sets according to embodiments of the present disclosure.

Fig. 19 is a schematic structural diagram of an electronic device according to an embodiment of the present application.

Detailed Description

As the smart terminal moves into the full-screen era, the fingerprint acquisition area on the front side of the electronic device is squeezed by the full-screen, and therefore the Under-screen (or Under-screen) fingerprint identification technology is receiving more and more attention. Fingerprint identification technology is installed in the display screen below with fingerprint identification device (for example fingerprint identification module) under the screen to realize carrying out the fingerprint identification operation in the display area inside of display screen, need not set up the fingerprint collection region in the positive region except that the display area of electronic equipment.

The underscreen fingerprint identification technology may include underscreen optical fingerprint identification technology, underscreen ultrasonic fingerprint identification technology, or other types of underscreen fingerprint identification technology.

Taking the example of an off-screen optical fingerprinting technique, the off-screen optical fingerprinting technique uses light returning from the top surface of the device display assembly for fingerprint sensing and other sensing operations. This returned light carries information about an object (e.g., a finger) in contact with the top surface, and the capture and detection of this returned light enables off-screen optical fingerprinting of a particular optical sensor module located below the display screen. The design of this particular optical sensor module may be such that the desired optical imaging is achieved by appropriately configuring the optical elements used to capture and detect the returned light.

It should be understood that the technical solutions of the embodiments of the present application may be applied to various electronic devices, and more particularly, may be applied to an electronic device having a display screen. For example, portable or mobile computing devices such as smart phones, notebook computers, tablet computers, and game devices, and other electronic devices such as electronic databases, automobiles, and Automatic Teller Machines (ATMs), but the present application is not limited thereto.

It should also be understood that, the technical solution of the embodiment of the present application may perform other biometric identification besides fingerprint identification, for example, living body identification, palm print identification, and the like, which is also not limited in the embodiment of the present application.

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

It should be noted that, for convenience of description, like reference numerals denote like parts in the embodiments of the present application, and a detailed description of the like parts is omitted in different embodiments for the sake of brevity.

It should be understood that the thickness, length, width and other dimensions of the various components in the embodiments of the present application and the overall thickness, length, width and other dimensions of the fingerprint recognition device shown in the drawings are only illustrative and should not be construed as limiting the present application in any way.

As shown in fig. 1, which is a schematic structural diagram of an electronic device to which the embodiment of the present application is applicable, the electronic device 1 includes a display screen 10 and a fingerprint identification device 20, where the fingerprint identification device 20 is disposed in a partial area below the display screen 10.

As an alternative implementation, as shown in fig. 1, the fingerprint identification device 20 includes an optical assembly 300 and a light detection array 400, the light detection array 400 and a reading circuit and other auxiliary circuits electrically connected to the light detection array, which may be fabricated on a chip (De) such as an optical imaging chip or an optical fingerprint sensor by a semiconductor process, the light detection array may be specifically a Photo detector (photodetector) array on the optical fingerprint sensor, which includes a plurality of photodetectors distributed in an array, and the photodetectors may be referred to as pixel units or pixels; the optical assembly 300 may be disposed above the light detecting array 400, and may specifically include a light guiding layer or a light path guiding structure for guiding the reflected light reflected from the surface of the finger to the sensing array for optical detection, and other optical elements. The area where the light detecting array 400 is located or the sensing area thereof is the fingerprint detection area 103 of the fingerprint identification device 20. As shown in fig. 1, the fingerprint detection area 103 is located in the display area of the display screen 10.

In an alternative embodiment, the fingerprint recognition device 20 may be disposed at other positions, such as the side of the display screen 10 or the edge non-light-transmissive area of the electronic apparatus 1, and the light signal of at least a part of the display area of the display screen 10 is guided to the fingerprint recognition device 20 by the light path design, so that the fingerprint detection area 103 is actually located at the display area of the display screen 10.

It should be understood that the area of the fingerprint detection area 103 may be different from the area of the light detection array 400 of the fingerprint identification device 20, for example, the area of the fingerprint detection area 103 of the fingerprint identification device 20 may be larger than the area of the light detection array 400 by the design of the optical path such as lens imaging, the design of the reflective folded optical path, or other optical path designs such as light converging or reflecting. In other alternative implementations, the fingerprint sensing area 103 of the fingerprint identification device 20 may be designed to substantially correspond to the area of the sensing array of the fingerprint identification device 20 if the optical path is directed in a light collimating manner, for example.

Therefore, when the user needs to unlock or otherwise verify the fingerprint of the electronic device, the user only needs to press a finger on the fingerprint detection area 103 of the display screen 10, so as to input the fingerprint. Because fingerprint detection can be realized under the screen, the electronic device 1 adopting the structure does not need special reserved space on the front surface to set a fingerprint key (such as a Home key), so that a full-screen scheme can be adopted, namely the display area of the display screen 10 can be basically expanded to the front surface of the whole electronic device 1.

In particular implementations, the optical assembly 300 may be packaged with the same optical fingerprint component as the light detection array 400. For example, the optical component 300 may be packaged in the same optical fingerprint chip as the light detecting array 400, or the optical component 300 may be disposed outside the chip where the light detecting array 400 is located, for example, the optical component 300 is attached to the chip, or some components of the optical component 300 are integrated into the chip.

For example, the light guide layer may be a Collimator (collimateror) layer fabricated on a semiconductor silicon wafer, and the collimater unit may be a small hole, and in the reflected light reflected from the finger, the light perpendicularly incident to the collimater unit may pass through and be received by the optical sensing unit below the collimater unit, and the light with an excessively large incident angle is attenuated by multiple reflections inside the collimater unit, so that each optical sensing unit can only receive the reflected light reflected from the fingerprint pattern directly above the optical sensing unit, and the sensing array can detect the fingerprint image of the finger.

In another embodiment, the light guiding layer or the light path guiding structure may also be an optical Lens (Lens) layer, which has one or more Lens units, such as a Lens group composed of one or more aspheric lenses, and is used to focus the reflected light reflected from the finger to the sensing array of the light detecting portion 134 therebelow, so that the sensing array can image based on the reflected light, thereby obtaining the fingerprint image of the finger. Optionally, the optical lens layer may further be formed with a pinhole in the optical path of the lens unit, and the pinhole may cooperate with the optical lens layer to enlarge the field of view of the optical fingerprint device, so as to improve the fingerprint imaging effect of the fingerprint identification device 20.

In other embodiments, the light guide layer or the light path guiding 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-lenses, which may be formed above the sensing array of the light detecting portion 134 through a semiconductor growth process or other processes, and each Micro-Lens may correspond to one of the sensing units of the sensing array. And, other optical film layers may be further formed between the microlens layer and the sensing unit, such as a dielectric layer or a passivation layer, and more specifically, a light blocking layer having micro holes may be further included between the microlens layer and the sensing unit, where the micro holes are formed between the corresponding microlenses and the sensing unit, and the light blocking layer may block optical interference between adjacent microlenses and the sensing unit, and enable light rays corresponding to the sensing unit to be converged into the micro holes through the microlenses and transmitted to the sensing unit through the micro holes to perform optical fingerprint imaging. It should be understood that several implementations of the above-described optical path directing structure may be used alone or in combination, for example, a microlens layer may be further disposed below the collimator layer or the optical lens layer. Of course, when the collimator layer or the optical lens layer is used in combination with the microlens layer, the specific lamination structure or optical path thereof may need to be adjusted according to actual needs.

It should be understood that in a specific implementation, the electronic device 1 further comprises a transparent protective cover 130, which may be a glass cover or a sapphire cover, positioned over the display screen 10 and covering the front face of the electronic device 1. Because, in the embodiment of the present application, the pressing of the finger on the display screen 10 actually means pressing on the cover plate above the display screen 10 or the surface of the protective layer covering the cover plate.

It should also be understood that a circuit board 150 may also be provided beneath the fingerprint recognition device 20. The fingerprint recognition device 20 can be adhered to the circuit board 150 by a back adhesive, and electrically connected to the circuit board 150 by soldering a pad and a wire. The fingerprint recognition device 20 can be electrically interconnected and signal-transmitted with other peripheral circuits or other components of the electronic apparatus 1 via the circuit board 150. For example, the fingerprint identification device 20 may receive a control signal of a processing unit of the electronic apparatus 1 through the circuit board 150, and may also output a fingerprint detection electrical signal from the fingerprint identification device 20 to the processing unit or the control unit of the electronic apparatus 1 through the circuit board 150, or the like.

On the other hand, in some embodiments, the fingerprint identification device 20 may only include one optical fingerprint sensor, where the area of the fingerprint detection area 103 of the fingerprint identification device 20 is small and the location is fixed, so that the user needs to press a finger to a specific location of the fingerprint detection area 103 when performing a fingerprint input, otherwise the fingerprint identification device 20 may not acquire a fingerprint image and the user experience is poor. In other alternative embodiments, the fingerprint recognition device 20 may specifically include a plurality of optical fingerprint sensors; the plurality of optical fingerprint sensors may be disposed side by side below the display screen 120 in a splicing manner, and sensing areas of the plurality of optical fingerprint sensors jointly form the fingerprint detection area 103 of the fingerprint identification device 20. That is, the fingerprint detection area 103 of the fingerprint identification device 20 may include a plurality of sub-areas, each of which corresponds to a sensing area of one of the optical fingerprint sensors, so that the fingerprint capture area 103 of the fingerprint identification device 20 may be extended to a main area of a lower half portion of the display screen, i.e., to a region where a finger is normally pressed, thereby implementing a blind-touch fingerprint input operation. Alternatively, when the number of optical fingerprint sensors is sufficient, the fingerprint detection area 103 may also be extended to half the display area or even the entire display area, thereby enabling half-screen or full-screen fingerprint detection.

It should be noted that, optical fingerprint device in this application embodiment also can be called optical fingerprint identification module, fingerprint identification device, fingerprint identification module, fingerprint collection device etc. but above-mentioned term mutual replacement.

It should be noted that, when the display screen 10 is a display screen having a self-luminous display unit, such as an Organic Light Emitting Diode (OLED) display screen or a Micro-LED (Micro-LED) display screen. Taking the OLED display screen as an example, the fingerprint identification device 20 may utilize the display unit (i.e., the OLED light source) of the OLED display screen 10 located in the fingerprint detection area 103 as an excitation light source for optical fingerprint detection. The display screen 10 emits a beam of light toward the target finger 140 above the fingerprint detection area 103, which is reflected at the surface of the finger 140 to form reflected light or scattered light via the inside of the finger 140 to form scattered light, which is collectively referred to as reflected light for convenience of description in the related patent application. Because the ridges (ridges) and the valleys (valley) of the fingerprint have different light reflection capacities, the reflected light from the ridges and the valleys of the fingerprint have different light intensities, and after passing through the optical assembly 300, the reflected light is received by the light detection array 400 in the fingerprint identification device 20 and converted into corresponding electrical signals, i.e., fingerprint detection electrical signals; fingerprint image data can be obtained based on the fingerprint detection electric signal, and fingerprint matching verification can be further performed, so that the optical fingerprint identification function is realized on the electronic device 1.

When the display screen 10 is a display screen without a self-luminous display unit, such as a liquid crystal display screen or other passive luminous display screens, a backlight module is required to be used as a light source of the display screen 10. Taking an application to a liquid crystal display having a backlight module and a liquid crystal panel as an example, in order to support fingerprint identification under the liquid crystal display, as shown in fig. 1, a display 10 includes a liquid crystal panel 110 and a backlight module 120, the backlight module 120 is used for emitting an optical signal to the liquid crystal panel 110, and the liquid crystal panel 110 includes a liquid crystal layer and a control circuit, which is used for controlling the deflection of the liquid crystal to transmit the optical signal.

Optionally, in this embodiment of the application, the electronic device 1 may further include an excitation light source 160 for optical fingerprint detection, the fingerprint identification apparatus 20 is disposed below the backlight module 120, when the finger 140 is pressed on the fingerprint detection area 103, the excitation light source 160 emits excitation light 111 to the target finger 140 above the fingerprint detection area 103, the excitation light 111 is reflected on the surface of the finger 140 to form a first reflected light 151 of a fingerprint ridge and a second reflected light 152 of a fingerprint valley, and the first reflected light 151 and the second reflected light 152 need to pass through the liquid crystal panel 110 and the backlight module 120 and then pass through the optical assembly 300, and are received by the light detection array 400 in the fingerprint identification apparatus 20 and converted into an electrical fingerprint detection signal. Optionally, in some embodiments, the excitation light source is an infrared light source, which does not affect normal display of the liquid crystal display, and performs fingerprint identification based on an infrared light signal, so as to remove interference of ambient light and improve fingerprint identification effect.

However, in this process, the film structure of the backlight module 120, especially the prism film, may cause a large interference to the image formation of the fingerprint recognition device 20.

For ease of understanding, a brief description of the backlight module 120 in the lcd panel will be given with reference to fig. 2.

As shown in fig. 2, the backlight module 120 includes a Light Source (Light Source), a Light guide plate (Light guide plate), a Diffuser (Diffuser), a prism Film (BEF), a Reflector (Reflector), and the like, wherein a Light signal of the Light Source enters the Light guide plate from a side surface, is converted into a uniformly distributed surface Light Source through scattering of the Light guide plate, and then enters the prism Film through a Light equalizing effect of the lower Diffuser. Because of the light-gathering function of the prism film, the light rays meeting a certain angle are emitted, the light rays which do not meet the angle are reflected again in the light guide plate and the diffusion plate, and are received by the prism film again after the light guide plate and the diffusion plate are acted, and the light rays meeting the angle requirement are emitted.

In general, in a backlight module, two prism films, that is, a prism film in a vertical direction and a prism film in a horizontal direction shown in fig. 2, are generally disposed, and the two prism films have the same structure but have different directions of ridges, and projections of the ridges of the two prism films on the same plane have an included angle of 90 °, which is a plane parallel to a liquid crystal panel in a display screen. The two prism films act together to ensure that optical signals within a range of 360 degrees on a horizontal plane are effectively converged to the liquid crystal panel.

In some embodiments, the light passing through the prism film is collected to 70 °, that is, the light signal passing through the prism film forms an angle between 0 and 70 ° with the direction perpendicular to the display screen, and the projection of the light signal on the display screen can be any angle between 0 and 360 °. Therefore, through set up the prism membrane in backlight unit, the effectual luminance that increases the front view, compare in the condition that does not set up the prism membrane, liquid crystal display's luminance has increased 70%. In some embodiments of the present application, the two prismatic films in the backlight assembly may also be referred to as brightness enhancing prismatic films.

Specifically, (a) in fig. 3 and (b) in fig. 3 show a three-dimensional structural view and a cross-sectional view of one prism film 121 in the backlight module 120 in the embodiment of the present application, where (b) in fig. 3 is a schematic cross-sectional view of (a) in fig. 3 on the XZ plane. The prism film 121 may be any one of the two prism films of fig. 2.

The prism film 121 is formed by regularly arranging a plurality of identical triangular prisms 1210 in a row on a substrate 1213, wherein each triangular prism 1210 is formed by upwardly protruding from the substrate 1213, each triangular prism 1210 has a structure having two inclined side surfaces, an included Angle is formed between the two inclined side surfaces, and is a vertex Angle (Apex Angle) of the triangular prism 1210.

In addition, the two inclined sides of one prism 1210 form angles with the horizontal plane, which are the two base angles of the prism, respectively. For example, as shown in fig. 3(b), two inclined side surfaces of the triangular prism 1210 are a first side surface 1211 and a second side surface 1212, respectively, the first side surface 1211 forms an angle with the horizontal direction, which is the first base angle α of the triangular prism 1210, and the second side surface 1212 forms an angle with the horizontal direction, which is the second base angle β of the triangular prism 1210. Also for convenience of description, in the present application, hereinafter, the two base angles of any one of the triangular prisms in the prism film are also referred to as the two base angles of the prism film, the first side surface of each of the triangular prisms in the prism film is referred to as a first prism film layer surface, and the second side surface of each of the triangular prisms in the prism film is referred to as a second prism film side surface.

Optionally, in order to improve the light condensing effect of the prism film, through experimental data statistics, the vertex angle of the prism film in the prior art is generally 90 °, and the light condensing effect of the prism film is optimal at the angle. If the vertex angle is not 90 °, a part of the optical signal may be lost, which may affect the display brightness of the liquid crystal display panel.

In order to ensure uniformity of light collection of the prism film, that is, to ensure a good light collection effect of light signals at each angle, two base angles in the prism film are generally equal, that is, areas of two side surfaces of the prism in the prism film are the same, and if an apex angle of the prism film is 90 °, the prism film is composed of a plurality of isosceles right-angle prisms arranged.

Because set up the prism membrane among the liquid crystal display and improve liquid crystal display's luminance, nevertheless the finger presses on liquid crystal display's surface, and fingerprint identification device sets up when carrying out fingerprint identification in the finger below, and from the light signal after finger reflection or scattering return, can be refracted for two light signals of equidirectional through the prism membrane to influence the fingerprint identification function under the liquid crystal display.

Fig. 4 is a schematic diagram of optical paths of a fingerprint identification device under a liquid crystal display screen for performing fingerprint identification, wherein the liquid crystal display screen 10 includes a liquid crystal panel 110 and a backlight module 120, the backlight module 120 includes a prism film 121 and other film layers 124, and the other film layers 124 include, but are not limited to, the film layer structures of the light guide plate, the reflective film, and the diffusion film in fig. 2.

As shown in fig. 4, the third reflected light 153 is a fingerprint detection light signal reflected or transmitted through a center area of the finger, the center area of the finger corresponds to a center area of the fingerprint detection area 103, the fingerprint identification device 20 is disposed below the center area of the fingerprint detection area 103, the third reflected light 153 is refracted by two sides of the prism film 121 to form a first refracted light 161 and a second refracted light 162 with different directions, and the first refracted light 161 and the second refracted light 162 cannot enter the optical assembly 300 of the fingerprint identification device 20 for imaging. Therefore, the light signal from the center of the finger cannot be received by the fingerprint identification device 20, a dark area is formed in the fingerprint image detected by the light detecting array 400 as shown in fig. 5, and the field of view of the fingerprint identification device 20 is divided into two parts, resulting in a serious field of view loss. In addition, because the fingerprint detection light signal takes place great change through prism membrane refraction back, not only produces the dark space in the fingerprint image that forms, still can make fingerprint identification device normally form images the fingerprint, causes the distortion of fingerprint image.

In addition, the fourth optical signal 154 is an ambient optical signal or a stray optical signal in another region outside the fingerprint detection region 103, and the fourth optical signal 154 is refracted by the prism film to form a large-angle refracted optical signal, enters the optical component 300 and is transmitted to the light detection array 400 by the optical component 300, and is imaged in the light detection array 400, thereby affecting the quality of the fingerprint image.

In summary, the prism film in the liquid crystal display screen affects the fingerprint detection optical signal, which causes the field loss of the fingerprint identification device and the image distortion of the fingerprint image, and thus the fingerprint identification under the screen cannot be realized.

It should be understood that, while fig. 4 illustrates the effect of one prism film on the fingerprint light signal, if two prism films are included in the lcd as shown in fig. 2, the other prism film may also interfere with the fingerprint light signal as described above, the center of the fingerprint image detected by the light detecting array 400 may form a dark area as shown in fig. 6, and the field of view of the fingerprint identification device 20 is divided into four, which results in a more serious loss of the field of view.

The application provides a fingerprint identification device suitable for liquid crystal display through increase the compensation prism membrane in backlight unit, compensates and revises the fingerprint light signal through blast prism membrane in the liquid crystal display to solve the problem of liquid crystal display below fingerprint image distortion and visual field loss among the prior art, improve fingerprint imaging quality and fingerprint identification performance under the liquid crystal display.

Hereinafter, the fingerprint recognition device according to the embodiment of the present application will be described in detail with reference to fig. 7 to 18.

Fig. 7 is a schematic structural diagram of a fingerprint identification apparatus 200 according to an embodiment of the present application, which is suitable for an electronic device having a liquid crystal display, and is configured to be disposed below a backlight module of the liquid crystal display for performing fingerprint identification under the display.

As shown in fig. 7, the fingerprint recognition device 200 includes: the fingerprint identification module 201 is arranged below the backlight module 120;

the backlight module 120 includes a brightness enhancement prism film 121 and a compensation prism film 122, the compensation prism film 122 is disposed below the brightness enhancement prism film 121 in parallel, a first fingerprint optical signal 101 received by the brightness enhancement prism film 121 passes through the brightness enhancement prism film 121 and the compensation prism film 122 to form a first target fingerprint optical signal 1011, the propagation directions of the first target fingerprint optical signal 1011 and the first target optical signal 101 are the same, wherein the first fingerprint optical signal 101 is an optical signal returned by finger reflection or scattering above the liquid crystal display screen;

this fingerprint identification module 201 is used for receiving the first fingerprint light signal 101 behind above-mentioned brightening prism membrane 121 and compensation prism membrane 122 to carry out fingerprint identification.

Optionally, in the embodiment of the present application, the fingerprint identification module 201 may be the fingerprint identification device 20 in fig. 1, which may include an optical assembly 300 and a light detection array 400.

The optical assembly 300 is configured to receive the first fingerprint optical signal 101 and transmit the first fingerprint optical signal to the optical detection array 400, and the optical detection array 400 is configured to convert the first fingerprint optical signal 101 into a fingerprint image signal for fingerprint identification.

Specifically, in the embodiments of the present application, the optical assembly 300 may be an optical Lens (Lens) layer having one or more Lens units, such as a Lens group composed of one or more optical lenses. Alternatively, the surface of the optical lens in the optical lens layer may be a spherical surface or an aspherical surface, and the material of the optical lens may be a transparent material such as glass or resin.

Specifically, in the embodiment of the present application, the light detection array 400 includes a plurality of sensing units. The sensing unit may use a Photodiode (PD), a Metal Oxide Semiconductor Field Effect Transistor (MOSFET), or other devices to detect an optical signal and output a fingerprint image signal. Optionally, the sensing unit has higher optical sensitivity and higher quantum efficiency for specific wavelength light, so as to detect optical signals of corresponding wavelength.

Optionally, the fingerprint identification module 201 may only include an optical fingerprint sensor, and the area of the fingerprint detection area 103 of the fingerprint identification module 201 is smaller and the position is fixed at this time. In other alternative embodiments, the fingerprint identification module 201 may specifically include a plurality of optical fingerprint sensors; this a plurality of optical fingerprint sensor can set up side by side in liquid crystal display's below through the concatenation mode, and this a plurality of optical fingerprint sensor's induction zone constitutes fingerprint detection area of fingerprint identification module 201 jointly.

Alternatively, in a possible implementation manner, the fingerprint identification device 200 may be applied to the electronic device 1, and may be specifically disposed below the backlight module 120 of the liquid crystal display 10, in this embodiment, reference may be made to the above description of the liquid crystal display 10 and the related features of the backlight module 120.

Alternatively, in the embodiment of the present application, the brightness enhancement prism film 121 may be the prism film 121 in the embodiment of fig. 3 to 4, which is used to enhance the brightness of the lcd panel. Specifically, the substrate of the brightness enhancing prism film 121 is below, and the first and second enhancement prism film sides, both of which face the liquid crystal panel 110 of the liquid crystal display screen, are convex toward above the substrate. In the present embodiment, the first sides of the plurality of triangular prisms in the brightness enhancing prism film 121 are each referred to as a first brightness enhancing prism film side, and the second sides of the plurality of triangular prisms are each referred to as a second brightness enhancing prism film side.

Specifically, since the optical signal passes through the brightness enhancement prism film 121 and then undergoes a large angular deviation, which is not beneficial for fingerprint recognition, the compensation prism film 122 is disposed below the brightness enhancement prism film 121 for correcting the large angular deviation optical signal passing through the brightness enhancement prism film 121, and the optical signal corrected by the compensation prism film 122 has the same angle as the optical signal received by the brightness enhancement prism film 121.

Specifically, the compensation prism film 122 is also a prism film structure, and the specific structure thereof can also refer to the related description in fig. 3a and 3b, specifically, the substrate of the compensation prism film 122 is above, and the first compensation prism film side and the second compensation prism film side thereof both protrude toward the lower side of the substrate, and both the first compensation prism film side and the second compensation prism film side face are opposite to the liquid crystal panel 110 of the liquid crystal display panel. In the embodiment of the present application, the first side surfaces of the plurality of triangular prisms in the compensation prism film 122 are referred to as first compensation prism film side surfaces, and the second side surfaces of the plurality of triangular prisms are referred to as second compensation prism film side surfaces.

In the embodiment of the present application, the substrates of the brightness enhancement prism film 121 and the compensation prism film 122 are parallel and are both parallel to the plane of the liquid crystal panel in the liquid crystal display panel. For convenience of description, in the present application, a plane in which a liquid crystal panel is located in a liquid crystal display panel is also referred to as a first plane, and in general, if the liquid crystal display panel is horizontally placed, the first plane is also a horizontal plane.

Specifically, the angle between the first brightness enhancing prism film side 1211 and its base, i.e., the angle between the first brightness enhancing prism film side 1211 and the first plane, is α₁The included angle between the first compensation prism film side surface 1221 and the base thereof, that is, the included angle between the first compensation prism film side surface 1221 and the first plane is α₂Wherein, 35 °<α₁≤45°，35°<α₂≤45°。

Alternatively, in one embodiment, the materials of the brightness enhancing prism film 121 and the compensation prism film 122 are the same or similar, i.e., the optical parameters of the brightness enhancing prism film 121 and the compensation prism film 122 are the same or similar, such as the refractive indices of the brightness enhancing prism film 121 and the compensation prism film 122 for the optical signal.

FIG. 8 shows a close-up schematic view of a portion of the brightness enhancing prism film 121 and the compensating prism film 122.

As shown in FIG. 8, the first brightness enhancing prism film side 1211 of the brightness enhancing prism film 121 is parallel to the first compensating prism film side 1221 of the compensating prism film 122, and the second brightness enhancing prism film side 1212 of the brightness enhancing prism film 121 is parallel to the second compensating prism film side 1222 of the compensating prism film 122, α in this case₁＝α₂。

The first brightness enhancement film side 1211 receives the optical signal a (an example of the first fingerprint optical signal), the optical signal a passes through the brightness enhancement prism film 121 and the compensation prism film 122, then is transmitted to the first compensation prism film side 1221 of the compensation prism film 122, and is refracted by the first compensation prism film side 1221, and then is emitted as an optical signal c (an example of the first target fingerprint optical signal), and the optical signal c and the optical signal a have the same propagation direction.

Similarly, in fig. 8, the second brightness enhancement prism film side 1212 receives the optical signal b (an example of the second fingerprint optical signal), the optical signal b passes through the brightness enhancement prism film 121 and the compensation prism film 122, then is transmitted to the second compensation prism film side 1222 of the compensation prism film 122, and is refracted by the second compensation prism film side 1222 to be emitted as the optical signal d (an example of the second target fingerprint optical signal), and the propagation directions of the optical signal d and the optical signal b are the same.

The angle between the second brightness enhancing prism film side 1212 and its substrate, i.e. the angle between the second brightness enhancing prism film side 1212 and the first plane, is β₁The angle between the second compensation prism film side 1222 and the substrate is β, i.e. the angle between the second compensation prism film side 1222 and the first plane is β₂Optionally β₁＝β₂。

At this time, the propagation direction of all the optical signals received by the brightness enhancement prism film 121 after passing through the brightness enhancement prism film 121 and the compensation prism film 122 is unchanged, the fingerprint identification module 201 may be placed directly below a finger, or directly below a fingerprint detection area, and receives target fingerprint optical signals (including a first target fingerprint optical signal and a second target fingerprint optical signal) formed after the fingerprint optical signals pass through the brightness enhancement prism film 121 and the compensation prism film 122, and detects and identifies a fingerprint image.

Specifically, as shown in fig. 7, the finger is located above the fingerprint detection area 103 in fig. 7, and the fingerprint identification module is located under the fingerprint detection area 103, i.e. the center of the fingerprint identification module coincides with the center of the fingerprint detection area 103 in the vertical direction, which is the direction perpendicular to the first plane.

It should be understood that, in addition to the above-described materials using the brightness enhancing prism film 121 and the compensation prism film 122 being the same, and the two prism film sides of the brightness enhancing prism film 121 and the two prism film sides of the compensation prism film 122 being disposed in parallel, respectively, such that the propagation direction of the fingerprint light signal is unchanged, the structures and materials of the brightness enhancing prism film 121 and/or the compensation prism film 122 may be adjusted in other ways such that the propagation direction of the fingerprint light signal is unchanged. For example, if the materials of the brightness enhancing prism film 121 and the compensating prism film 122 are different, the fingerprint light signal propagation direction through the two prism films can be kept unchanged by adjusting the positions of the prism film side surfaces of the brightness enhancing prism film 121 and the compensating prism film 122.

Adopt the scheme of this application embodiment, set up the compensation prism membrane through the blast prism membrane below at backlight unit, make the direction of propagation through backlight unit's fingerprint light signal unchangeable, therefore, set up the compensation prism membrane through the increase, offset the influence that original blast prism membrane brought the fingerprint light signal, make the fingerprint identification module that is located the finger below can receive the fingerprint light signal smoothly, and carry out fingerprint formation of image according to fingerprint light signal, eliminate in the fingerprint image because the image distortion influence that the fingerprint light signal direction change brought, in the luminance that can improve liquid crystal display, can also improve the quality of fingerprint image, satisfy fingerprint identification demand under the liquid crystal display.

Meanwhile, the included angle between the side face of the first brightening prism film and the first plane is set, and the included angle between the side face of the first compensating prism film and the first plane is 35-45 degrees, so that the brightness requirement of the liquid crystal display screen can be still met on the premise that the fingerprint identification requirement under the liquid crystal display screen is met.

Alternatively, in order to secure the brightness of the liquid crystal display panel, in the embodiment shown in fig. 8, the plurality of triangular prisms in the brightness enhancing prism film 121 are a plurality of right-angled triangular prisms, wherein the apex angle γ of the brightness enhancing prism film₁Is 90 degrees and β degrees₁＝90°-α₁。

Further, in order to ensure the uniformity of the brightness of the lcd panel, the included angle α between the side surfaces of two of the brightness enhancement prism films 121 and the first plane is₁And β₁The difference value of (a) is smaller than a preset threshold value, the preset threshold value includes but is not limited to a value smaller than or equal to 15 °, and the specific threshold value is not limited in the embodiment of the present application.

For example, in the first case, α₁＝α₂＝40°，β₁＝β₂50 deg. or, in the second case, α₁＝α₂＝38°，β₁＝β₂52 deg., wherein the first case had two base angles α in the brightness enhancing prism film as compared to the second case₁And β₁The difference value of (2) is smaller, the values of the two base angles are more balanced, and the improvement of the brightening effect of the brightening prism film on the liquid crystal display screen is facilitated.

In some embodiments, the predetermined thresholdThe value 0, the plurality of prisms in the brightness enhancing prism film 121 are isosceles right triangular prisms having two base angles α₁And β₁The sizes are the same and are 45 degrees, and the apex angle gamma of the brightening prism film₁The angle is 90 degrees, and the brightness enhancement effect of the liquid crystal display screen is optimal at the moment.

Further, as shown in fig. 8, the Pitch (Pitch) between the ridges of two adjacent triangular prisms in the brightness enhancing prism film 121 is P1, and the Pitch between the ridges of two adjacent triangular prisms in the compensation prism film 122 is P2, P1 is P2, and optionally P1 is P2 is 24 μm. At this time, the brightness enhancing prism film 121 and the compensating prism film 122 in fig. 8 are disposed in an axisymmetric manner.

Optionally, the distance P1 between the ridges of two adjacent prisms in the brightness enhancement prism film 121 may also be different from the distance P2 between the ridges of two adjacent prisms in the compensation prism film 122, so as to ensure that the side surfaces of the two compensation prism films in the compensation prism film 122 are parallel to the side surfaces of the two brightness enhancement prism films in the brightness enhancement prism film 121, which is not specifically limited by the embodiment of the present application.

In some embodiments, the pitch values P1 and P2 may be any value between 15 μm and 40 μm.

Alternatively, the distance between the substrate of the brightness enhancement prism film 121 and the substrate of the compensation prism film 122 may be less than or equal to a certain threshold value to save space in the backlight module 120 and reduce the thickness of the backlight module, in some embodiments, the distance z between the substrate of the brightness enhancement prism film 121 and the substrate of the compensation prism film 122 is less than or equal to 1 μm.

In addition, the thickness of the substrate of the brightness enhancement prism film 121 may be equal to or different from the thickness of the substrate of the compensation prism film 122, and the thickness of the substrates of the two prism films is not specifically limited in the embodiment of the present application.

Of course, in addition to fig. 8 that the plurality of triangular prisms in the brightness enhancement prism film 121 are isosceles right triangular prisms in order to ensure the brightness of the liquid crystal display, the brightness enhancement prism film 121 may also be a prism film with other structures, where the plurality of triangular prisms include but are not limited to isosceles right triangular prisms, isosceles obtuse triangular prisms, non-isosceles triangular prisms, and the like, and the specific structure of the brightness enhancement prism film 121 is not specifically limited in the embodiment of the present application.

Likewise, where the brightness enhancing prism film 121 is of another configuration, the two compensating prism film sides in the compensating prism film 122 may likewise be parallel to the two brightness enhancing prism film sides in the brightness enhancing prism film 121, respectively, and the spacing between the ridges of two adjacent prisms in the compensating prism film 122 may be equal to the spacing between the ridges of two adjacent prisms in the brightness enhancing prism film 121.

In the above application embodiment, by additionally arranging the compensation prism film 122, the compensation prism film 122 keeps the propagation direction of all fingerprint light signals unchanged after passing through the backlight module, thereby solving the problem of fingerprint image distortion and meeting the requirement of fingerprint identification.

However, in this case, as shown in fig. 8, the optical signal b and the optical signal e are parallel optical signals, which are received by the second prism film side 1212 and the first prism film side 1211 of the brightness enhancement prism film 121, respectively, and are refracted by the two prism film sides, and then the two optical signals intersect with each other, and although the optical signal d and the optical signal f emitted after passing through the compensation prism film 122 are also parallel optical signals, actually, fingerprint regions represented by the two optical signals intersect with each other, and if the optical signal d and the optical signal f are received by the fingerprint recognition module at the same time and fingerprint imaging is performed, there is a problem that a ghost image is generated in a fingerprint image.

Therefore, in order to further improve the quality of the fingerprint image, solve the problem of ghost in the fingerprint image, and improve the fingerprint identification effect, the following describes another structure of the compensation prism film in conjunction with fig. 9 and 10.

FIG. 9 shows another enlarged partial schematic view of the brightness enhancing prism film 121 and the compensating prism film 122.

As shown in fig. 9, the first brightness enhancing prism film side 1211 of the brightness enhancing prism film 121 is parallel to the first compensating prism film side 1221 of the compensating prism film 122, but the second brightness enhancing prism film side 1212 of the brightness enhancing prism film 121 is not parallel to the second compensating prism film side 1222 of the compensating prism film 122.

The first brightness enhancement prism film side 1211 receives the optical signal a and the optical signal e (another example of the first fingerprint optical signal), the optical signal a passes through the brightness enhancement prism film 121 and the compensation prism film 122, then is transmitted to the first compensation prism film side 1221 of the compensation prism film 122, and is refracted by the first compensation prism film side 1221 to be emitted as the optical signal c, and the optical signal c and the optical signal a have the same propagation direction. Similarly, the optical signal e passes through the brightness enhancement prism film 121 and the compensation prism film 122, and then exits as an optical signal f (another example of the first target fingerprint optical signal), which has the same propagation direction as the optical signal e.

The second brightness enhancement prism film side 1212 receives the optical signal b (an example of the second fingerprint optical signal), the optical signal b passes through the brightness enhancement prism film 121 and the compensation prism film 122, then is transmitted to the second compensation prism film side 1222 of the compensation prism film 122, and is reflected by the second compensation prism film side 1222 to be emitted as the optical signal d (an example of the non-target fingerprint optical signal).

Specifically, as shown in fig. 9, the light signal received by the second compensation prism film side 1222 of the compensation prism film 122 has a large incident angle, and at this time, the reflected light intensity is large and the refracted light intensity is small, and the light signal passing through the second compensation prism film side 1222 exits the compensation prism film mainly as the reflected light signal, forming a light signal d.

In this case, the first brightness enhancing prism film side 1211 makes an angle α with the first plane₁And the included angle between the first compensation prism film side surface 1221 and the first plane is α₂But the second brightness enhancing prism film side 1212 makes an angle β with the first plane₁β from the second compensation prism film side 1222 and the first plane₂Not equal.

At this time, the propagation direction of the light signal received by the first prism film side 1211 of the brightness enhancement prism film 121 after passing through the brightness enhancement prism film 121 and the compensation prism film 122 is unchanged, and the fingerprint identification module 201 may be placed right under a finger, receive the first fingerprint light signal after passing through the first brightness enhancement prism film side 1211 and the first compensation prism film side 1221, generate a fingerprint image based on the first fingerprint light signal, and perform fingerprint identification on the fingerprint image.

The optical signal d is not the first fingerprint optical signal 101 in fig. 7, and the propagation direction of the optical signal received by the second prism film side 1212 of the brightness enhancement prism film 121 after passing through the brightness enhancement prism film 121 and the compensation prism film 122 is changed, so that the optical signal cannot be received by the fingerprint identification module 201. Consequently, light signal d and light signal f if not receive by the fingerprint identification module simultaneously, can solve the ghost image problem in the fingerprint image, further improve the quality of fingerprint image and fingerprint identification's performance.

Adopt the scheme of this application embodiment, set up the compensation prism membrane of special construction through the brightening prism membrane below backlight unit for the propagation direction of the partial fingerprint light signal through backlight unit is unchangeable, so, in improving liquid crystal display luminance, eliminating the fingerprint image because the image distortion influence that the fingerprint light signal direction change brought, still solved the ghost image problem in the fingerprint image, further improve the quality of fingerprint image and fingerprint identification's performance.

Alternatively, referring to FIG. 9, in the present embodiment, to provide strong reflection of the light signal received at the second compensating prism film side 1222 in the compensating prism film 122, the propagation direction of the light signal is changed to a greater extent, relative to the angle β between the second brightness enhancing prism film side 1212 and the first plane₁In other words, the angle β between the second compensation prism film side 1222 and the first plane can be set₂The setting is larger or smaller, and the problem of ghosting is solved.

If β₂＞β₁And α₁＝β₁Then, correspond to, β₂＞α₁＝α₂Then the area of second compensation prism membrane side 1222 is less than the area of first compensation prism membrane side 1221, if under this condition, the fingerprint identification module receives the fingerprint light signal that passes through first compensation prism membrane side 1221, compares in receiving the fingerprint light signal that passes through second compensation prism membrane side 1222, can produce great optics visual field, and the fingerprint area of its collection is bigger, more is favorable to carrying out fingerprint detection and fingerprint identification.

On the contrary, if β₂＜β₁And α₁＝β₁Then, correspond to, β₂＜α₁＝α₂In this case, the problem of ghosting can be solved, but a large optical field of view cannot be obtained.

Alternatively, in the above-described compensation prism film, β₂＞α₂Wherein 35 ° < α₂≤45°。

Alternatively, β₂At 90 °, for example α₂＝38°，β₂At 90 °, alternatively, α₂＝40°，β₂At 90 °, alternatively, α₂＝45°，β₂＝90°。

Wherein, if α₂At 38 °, the angle α between the first brightness enhancing prism film side 1211 of the brightness enhancing prism film 121 and the first plane is₁Also equal to 38 deg., the top angle of the brightness enhancement prism film is 90 deg. in order to ensure the brightness enhancement effect of the lcd panel, therefore, the included angle β between the side face 1212 of the second brightness enhancement prism film and the first plane in the brightness enhancement prism film 121₁＝52°。

Similarly, if α₂α degree in the brightness enhancement prism film₁At 40 deg. to ensure brightness enhancement of lcd panel, β₁Compare 50 °. to α above₂At 38 deg., two base angles α in the brightness enhancing prism film₁And β₁The difference value of (2) is smaller, the values of the two base angles are more balanced, and the improvement of the brightening effect of the brightening prism film on the liquid crystal display screen is facilitated.

Similarly, if α₂α deg. in the brightness enhancement prism film₁At 45 deg., β for ensuring brightness enhancement effect of LCD screen₁45 deg. is equal to. At this time, the brightening effect of the liquid crystal display screen is optimal.

Therefore, in the embodiment of the present application, if the angle α between the side surface of the first compensation prism film and the first plane is defined in the compensation prism film₂And the brightness enhancement effect of the liquid crystal display screen can be improved by approaching to 45 degrees.

Further, as shown in fig. 9, in the embodiment of the present application, the pitch between the ridges of two adjacent triangular prisms in the brightness enhancement prism film 121 may also be equal to the pitch between the ridges of two adjacent triangular prisms in the compensation prism film 122, for example, both of 24 μm or other values.

Optionally, in the embodiment of the present application, the distance between the substrate of the brightness enhancement prism film 121 and the substrate of the compensation prism film 122 may be less than or equal to a certain threshold value to save space in the backlight module 120 and reduce the thickness of the backlight module, and in some embodiments, the distance z between the substrate of the brightness enhancement prism film 121 and the substrate of the compensation prism film 122 is less than or equal to 1 μm.

It should be understood that fig. 9 is illustrated by way of example of the first brightness enhancement prism film side 1211 in the brightness enhancement prism film 121 being parallel to the first compensation prism film side 1221 in the compensation prism film 122, and that it is also possible that the second brightness enhancement prism film side 1212 in the brightness enhancement prism film 121 is parallel to the second compensation prism film side 1222 in the compensation prism film 122, and the first brightness enhancement prism film side 1211 is not parallel to the first compensation prism film side 1221, and the light signals received by the second brightness enhancement prism film side are received by the fingerprint recognition module after passing through the brightness enhancement prism film and the compensation prism film, and the light signals received by the first prism brightness enhancement film side are received by the fingerprint recognition module after passing through the prism brightness enhancement film and the compensation prism film. Corresponding other related features can refer to the related description in the embodiment of fig. 9 above, and are not described herein again.

FIG. 10 shows another enlarged partial schematic view of the brightness enhancing prism film 121 and the compensating prism film 122.

As shown in fig. 10, the structure of the brightness enhancing prism film 121 and the compensating prism film 122 may be the same as in fig. 8, i.e., the first brightness enhancing prism film side 1211 of the brightness enhancing prism film 121 is parallel to the first compensating prism film side 1221 of the compensating prism film 122, and the second brightness enhancing prism film side 1212 of the brightness enhancing prism film 121 is parallel to the second compensating prism film side 1222 of the compensating prism film 122. The materials of the brightness enhancement prism film 121 and the compensation prism film 122 are the same or similar, the two brightness enhancement prism film sides of the brightness enhancement prism film 121 face the liquid crystal panel of the liquid crystal display, and the two compensation prism film sides of the compensation prism film 122 face away from the liquid crystal panel of the liquid crystal display.

On this basis, in order to solve the ghost image problem, so that the fingerprint identification module located below the brightness enhancement prism film 121 and the compensation prism film 122 cannot receive the fingerprint light signal received by one of the brightness enhancement prism film sides of the brightness enhancement prism film 121, a light absorbing material, such as black ink, may be coated on the first compensation prism film side 1221 or the second compensation prism film side 1222 of the compensation prism film 122, so that the fingerprint light signal passing through the prism film side coated with the light absorbing material is absorbed and cannot be received by the fingerprint identification module.

For example, as shown in fig. 10, the light absorbing material is coated on the second compensating prism film side 1222 of the compensating prism film 122, the light signal b received by the second brightness enhancing prism film side 1212 of the brightness enhancing prism film 121 passes through the brightness enhancing prism film 121, is transmitted to the second compensating prism film side 1222, and is absorbed by the light absorbing material above the second compensating prism film side 1222, but the light signal a and the light signal e received by the first brightness enhancing prism film side 1211 of the brightness enhancing prism film 121 pass through the brightness enhancing prism film 121, are transmitted to the first compensating prism film side 1221, and are emitted as the light signal c and the light signal f, and are received by the fingerprint recognition module.

Optionally, in this embodiment of the application, in order to improve the optical field of view of the fingerprint identification module, the area of the side surface of the first compensation prism film in the compensation prism film may be designed to be larger, and the area of the side surface of the first compensation prism film is larger than the area of the side surface of the second compensation prism film. Correspondingly, the area of the side of the first brightness enhancing prism film is larger than the area of the side of the second brightness enhancing prism film.

Alternatively, in addition to implementing the scheme of FIG. 10 based on the structures of the brightness enhancing prism film 121 and the compensating prism film 122 of FIG. 8, a light absorbing material may be coated on the second compensating prism film side 1222 of the compensating prism film 122 based on the structures of the brightness enhancing prism film 121 and the compensating prism film 122 of FIG. 9, at which time it may be further ensured that the light signal passing through the second compensating prism film side 1222, i.e., the light signal originating from the second brightness enhancing prism film side of the brightness enhancing prism film, is not received by the fingerprint identification module.

In the embodiment of the present application, it is sufficient to ensure that the first side 1211 of the brightness enhancement prism film is parallel to the first side 1221 of the compensation prism film 122, and the angle parameters of the brightness enhancement prism film and the compensation prism film are not specifically limited in the embodiment of the present application.

In other words, in embodiments of the present application, the second brightness enhancing prism film side 1212 may be parallel to the second compensating prism film side 1222, as shown in FIG. 10, and the structures of the brightness enhancing prism film and the compensating prism film may be the same as those in FIG. 8. The second brightness enhancing prism film side 1212 and the second compensating prism film side 1222 may also be non-parallel, and the structures of the brightness enhancing prism film and the compensating prism film may be the same as in FIG. 9.

In the above embodiment of fig. 8-10, a plurality of brightness enhancing prisms in the brightness enhancing prism film 121 and a plurality of compensating prisms in the compensating prism film 122 are in one-to-one correspondence, one compensating prism being located directly below its corresponding brightness enhancing prism, and in the embodiment of fig. 8 and 10, the ridges of the corresponding compensating and brightness enhancing prisms coincide in a vertical direction, which is a direction perpendicular to the first plane. Specifically, a first compensating prism in the compensating prism film corresponds to a first brightness enhancing prism film in the brightness enhancing prism film, the ridge of the first compensating prism coincides with the projection of the ridge of the first brightness enhancing prism on the first plane, and the projection of the substrate of the first compensating prism on the first plane coincides with the projection of the substrate of the first brightness enhancing prism on the first plane.

Alternatively, in addition to the above embodiments, the ridges of the corresponding compensating and brightness enhancing prisms may also be misaligned in the vertical direction.

For example, in one embodiment, FIG. 11 shows a cross-sectional view of a compensating prism film and a brightness enhancing prism film, where the dashed box is a cross-sectional view of a compensating prism and its corresponding brightness enhancing prism, the ridge of the compensating prism being parallel to the ridge of the brightness enhancing prism, but the ridge of the compensating prism not vertically coincident with the ridge of the brightness enhancing prism. Fig. 12 shows a schematic view of the projection of the ridges of the compensating triangular prisms and of the brightness enhancing triangular prisms onto a first plane in this case. In this case, it is understood that the compensation prism film is translated in the X direction in fig. 11 on the basis of fig. 8, and likewise, the compensation prism film may be translated in the-X direction in fig. 11 on the basis of fig. 8, and after the translation, the projection of the ridge of one compensation prism (e.g., the first compensation prism in the compensation prism film) on the first plane is located in the projection of the substrate of the corresponding brightness enhancement prism (e.g., the first brightness enhancement prism in the brightness enhancement prism film) on the first plane.

For another example, in another embodiment, as shown in FIG. 13, which shows another case of a schematic projection diagram of ridges of a plurality of compensating prisms and ridges of a plurality of brightness enhancing prisms onto a first plane, wherein a solid line represents the ridges of the plurality of brightness enhancing prisms, a dashed line represents the ridges of the plurality of compensating prisms, and the ridge of one brightness enhancing prism (e.g., the first brightness enhancing prism) and the ridge of its corresponding one compensating prism (e.g., the first compensating prism) have an included angle θ, optionally 0 ° ≦ θ ≦ 20 °. In this case, it can be understood that, on the basis of fig. 8, the compensation prism film is rotated along the plane thereof by an angle within ± 20 ° with the center thereof as the axis point.

In addition, in the third embodiment, the compensation prism film may be translated and then rotated, and at this time, the projections of the ridges of the plurality of compensation triangular prisms and the ridges of the plurality of brightness enhancing triangular prisms on the first plane may be as shown in fig. 14.

Similarly, for the embodiment in fig. 9, on the basis of the above, the compensation prism film may be translated in the X direction in fig. 11, and/or rotated along the plane thereof with its center as the pivot point.

In the embodiment of the application, through proper translation and proper rotation translation, too large influence on the light path of the fingerprint optical signal cannot be caused, and the requirement of fingerprint identification can still be met.

Under this condition, can reduce the requirement of the relative position relation between compensation prism membrane and the brightening prism membrane to reduce the technological requirement of prism membrane assembly, can improve backlight unit's yield, and improve fingerprint identification device fingerprint identification's stability.

The structures of a set of brightness enhancing prism films 121 and compensating prism films 122, and the light paths are described above in conjunction with fig. 7 to 14.

If only one brightness enhancing prism film 121 is included in the liquid crystal display panel, a compensation prism film 122 is required to be provided corresponding to the brightness enhancing prism film 121. Alternatively, as shown in fig. 2, if two brightness enhancement prism films are included in the liquid crystal display panel, it is necessary to provide their corresponding compensation prism films, i.e., two compensation prism films 122, to the two brightness enhancement prism films, respectively.

Specifically, one brightness enhancement prism film and one compensation prism film form one prism film group, in the embodiment of the present application, the backlight module of the liquid crystal display panel includes two prism film groups, and any one of the two prism film groups may be the prism film group in any one of the above cases of fig. 8 to 10.

For another prism film group, the structure thereof can also refer to the prism film group in any one of the above fig. 8 to 10, only the spatial position is different from the previous prism film group.

Fig. 15 shows a schematic perspective view of two prism film sets. Fig. 16 shows a schematic cross-sectional view of the two prism film groups in fig. 15 on the XZ plane.

As shown in fig. 15 and 16, the upper two prism films are a first prism film group 210, and the lower two prism films are a second prism film group, and the upper first prism film group 210 may include a first brightness enhancement prism film 211 and a first compensation prism film 212, wherein the first compensation prism film 212 is disposed in parallel below the first brightness enhancement prism film 211. The lower second prism module 220 includes a second brightness enhancing prism film 221 and a second compensating prism film 222, wherein the second compensating prism film 222 is disposed in parallel below the second brightness enhancing prism film 221.

Alternatively, the structure of the first and second brightness enhancing

prism films

211 and 212 may be referred to above as the structure of the brightness enhancing prism film 121 in any of the embodiments of FIGS. 8-10, and the structure of the first and second compensating

prism films

221 and 222 may be referred to above as the structure of the compensating prism film 122 in any of the embodiments of FIGS. 8-10.

In general, the structure of the first brightness enhancing prism film 211 is the same as the structure of the second brightness enhancing prism film 212, and in this case the structure of the first compensating prism film 221 is the same as the structure of the second compensating prism film 222. If the first brightness enhancing prism film 211 and the second brightness enhancing prism film 212 are configured differently, the first compensating prism film 221 and the second compensating prism film 222 are adjusted to correspond to their respective brightness enhancing prism film configurations.

Specifically, in the present embodiment, the first and second brightness enhancing

prism films

211 and 212 may be vertically oriented prism films and horizontally oriented prism films in fig. 2, and the included angle of the projection of the ridges of the plurality of prisms in the first plane of the prism films of the first and second brightness enhancing

prism films

211 and 212 is 90 °.

Correspondingly, if the ridges of the prisms in the first compensating prism film 212 are parallel to the ridges of the prisms in the first brightness enhancing prism film 211, and the ridges of the prisms in the second compensating prism film 222 are parallel to the ridges of the prisms in the second brightness enhancing prism film 212, the projected angles of the ridges of the prisms in the first compensating prism film 212 and the second compensating prism film 222 on the first plane are 90 °.

The two prism film groups may be arranged in other ways than the arrangement shown in fig. 15 and 16. For example, fig. 17 and 18 show cross-sectional views of two other arrangements.

In the embodiment of the present application, in the same prism film group, it is sufficient that the positional relationship of the compensation prism film below the brightness enhancement prism film is satisfied, and the specific arrangement manner of the prism films is not limited in the embodiment of the present application.

It should be understood that, in the embodiment of the present application, the intervals between every two adjacent prism films of the four prism films may be equal or unequal, and this is not specifically limited in the embodiment of the present application.

It should also be understood that, in the embodiment of the present application, other optical film layers in the backlight module may be disposed between the four prism films, and other film layers may not be disposed between the four prism films, which is also not specifically limited in the embodiment of the present application.

In addition, in the embodiments of the present application, the compensation prism film is disposed in the backlight module, optionally, the compensation prism film may also be disposed between the liquid crystal display and the fingerprint identification module, and the specific position of the compensation prism film is not limited in the embodiments of the present application.

In addition, the embodiment of the application also provides a backlight module, which is suitable for electronic equipment with a liquid crystal display screen, wherein the liquid crystal display screen comprises the backlight module 120;

alternatively, the related features of the backlight module 120 in the embodiment of the present application can be referred to the related description of the backlight module 120 in the above embodiment, and the related features of the brightness enhancement prism film 121 and the compensation prism film 122 can also be referred to the related description of the two prism films in the above embodiments.

Specifically, the backlight module 120 includes: the liquid crystal display panel comprises a brightening prism film 121 and a compensating prism film 122, wherein the compensating prism film 122 is arranged below the brightening prism film 121 in parallel, the compensating prism film 122 faces away from a liquid crystal panel in the liquid crystal display panel, and the brightening prism film 121 faces towards the liquid crystal panel; wherein the brightness enhancing prism film 121 includes a first brightness enhancing prism film side 1211, the compensation prism film 122 includes a first compensation prism film side 1221, and the first brightness enhancing prism filmThe side 1211 forms an angle α with the plane of the liquid crystal display₁The included angle between the first compensation prism film side surface 1221 and the plane where the liquid crystal display screen is located is α₂，35°<α₁≤45°，35°<α₂≤45°。

In some embodiments of the present application, the first fingerprint light signal passes through the first brightness enhancement prism film side 1211 and the first compensation prism film side 1221 to form a first target fingerprint light signal, and the first target fingerprint light signal is used for fingerprint recognition, where the first target fingerprint light signal and the first fingerprint light signal travel in the same direction, and the first fingerprint light signal is a light signal reflected or scattered back by a finger above the liquid crystal display.

In some embodiments of the present application, the material of the brightness enhancing prism film 121 and the compensating prism film 122 are the same, and the first compensating prism film side 1221 is parallel to the first brightness enhancing prism film side 1211, α₁＝α₂。

In some embodiments of the present application, the brightness enhancing prism film 121 further comprises a second compensating prism film side 1212, the compensating prism film 122 further comprises a second compensating prism film side 1222, and the second compensating prism film side 1212 makes an angle β with the plane of the liquid crystal display screen₁The angle between the second compensation prism film side 1222 and the plane of the liquid crystal display panel is β₂，β₁≥α₁，β₂≥α₂。

In some embodiments of the present application, β₁＝90°-α₁。

In some embodiments of the present application, α₁And β₁The difference value of (2) is less than or equal to a preset threshold value so as to improve the brightness of the liquid crystal display screen.

In some embodiments of the present application, the second compensating prism film side 1222 is non-parallel to the second compensating prism film side 1212, β₁≠β₂(ii) a The second fingerprint optical signal passes through the second compensation prism film side 1212 and the second compensation prism film 122 to form a non-target fingerprint optical signal, the propagation directions of the non-target fingerprint optical signal and the second fingerprint optical signal are different, and the non-target fingerprint optical signal is generatedThe signal is not used for fingerprint identification, and the second fingerprint light signal is a light signal reflected or scattered back by a finger above the liquid crystal display screen.

In some embodiments of the present application, when the second fingerprint light signal passes through the brightness enhancement prism film 121 and then travels to the second compensation prism film side 1222, most of the second fingerprint light signal is reflected by the second compensation prism film 122 to form a non-target fingerprint light signal.

In some embodiments of the present application, β₂＝90°。

In some embodiments of the present application, the second compensating prism film side 1222 is parallel to the second compensating prism film side 1212, β₁＝β₂(ii) a The second fingerprint optical signal forms a second target fingerprint optical signal after passing through the second compensation prism film side 1212 and the second compensation prism film 122, the propagation direction of the second target fingerprint optical signal is the same as that of the second fingerprint optical signal, the second target fingerprint optical signal is used for fingerprint identification, and the second fingerprint optical signal is an optical signal returned by reflection or scattering of a finger above the liquid crystal display screen.

In some embodiments of the present application, the second target fingerprint light signal passing through the second compensation prism film side 1222 and the first target fingerprint light signal passing through the first compensation prism film side 1221 are both received by the fingerprint identification module for fingerprint identification.

In some embodiments of the present application, a light absorbing material is disposed on the second compensation prism film side 1222 to absorb light signals received by the second compensation prism film side 1222.

In some embodiments of the present application, the number of compensating prisms in the compensating prism film 122 is equal to the number of brightness enhancing prisms in the brightness enhancing prism film 121, and a plurality of compensating prisms in the compensating prism film 122 correspond one-to-one to a plurality of brightness enhancing prisms in the brightness enhancing prism film 121; the distance between the ridges of two adjacent compensating prisms in the plurality of compensating prisms is equal to the distance between the ridges of two adjacent brightness enhancing prisms in the plurality of brightness enhancing prisms.

In some embodiments of the present application, a first compensating prism in the compensating prism film 122 corresponds to a first brightness enhancing prism film 121 in the brightness enhancing prism film 121, the projection of the ridge of the first compensating prism and the ridge of the first brightness enhancing prism on a first plane has an included angle θ, θ is greater than or equal to 0 ° and less than or equal to 20 °, and the first plane is a plane parallel to the liquid crystal display panel.

In some embodiments of the present application, a first compensating prism in the compensating prism film 122 corresponds to a first brightness enhancing prism film 121 in the brightness enhancing prism film 121, and the projection of the ridge of the first compensating prism onto a first plane is in the projection of the substrate of the first brightness enhancing prism onto the first plane, which is a plane parallel to the liquid crystal display.

In some embodiments of the present application, the projection of the prism base of the first compensating prism onto the first plane coincides with the projection of the prism base of the first brightness enhancing prism onto the first plane.

In some embodiments of the present application, two brightness enhancing prism films 121 and two compensating prism films 122 are included; the two brightness enhancement prism films 121 and the two compensation prism films 122 are arranged below the liquid crystal display screen in parallel and are positioned on different planes; two compensating prism films 122 are respectively disposed below the two brightness enhancing prism films 121.

In some embodiments of the present application, the projection of the ridge of one brightness enhancing prism in one brightness enhancing prism film 121 of the two brightness enhancing prism films 121 onto a first plane is perpendicular to the ridge of one brightness enhancing prism in the other brightness enhancing prism film 121; the projection of the ridge of one compensating prism in one compensating prism film 122 of the two compensating prism films 122 and the ridge of one compensating prism in the other compensating prism film 122 on a first plane, which is a plane parallel to the liquid crystal display screen, are perpendicular to each other.

In some embodiments of the present application, the distance between each adjacent two of the two brightness enhancing prism films 121 and the two compensating prism films 122 is equal.

As shown in fig. 19, an electronic device 2 is further provided in the embodiment of the present application, where the electronic device 2 may include the liquid crystal display 10 and the fingerprint identification device 200 in the embodiment of the present application, where the liquid crystal display 10 includes the backlight module 120 in the embodiment of the present application, and the fingerprint identification device 200 is disposed below the backlight module 120.

Alternatively, the electronic device 2 may be any electronic device having a liquid crystal display and a backlight module.

Optionally, the electronic device 2 may also include an infrared light source 30. An infrared excitation light for fingerprint detection of the fingerprint recognition device 200, wherein the infrared excitation light irradiates at least a part of the display area of the liquid crystal display 10, and the at least a part of the display area at least partially covers the fingerprint detection area of the fingerprint recognition device 200; wherein, infrared light source 30's infrared excitation light forms target fingerprint infrared light signal through this backlight unit after the finger reflection or the scattering of this fingerprint detection area top, and fingerprint identification device 200 is used for receiving this target fingerprint infrared light signal and carries out fingerprint identification.

Alternatively, the infrared light source 30 may be disposed below the glass cover 130 of the electronic device, and be disposed side by side with the liquid crystal panel of the liquid crystal display.

In one possible embodiment, as shown in fig. 19, the infrared light source 30 is disposed below the glass cover 130 of the electronic device 2, is disposed side by side with the liquid crystal panel 110 of the liquid crystal display panel 10, and is disposed obliquely above the backlight module 120 of the liquid crystal display panel 10. Specifically, the backlight module 120 includes a first prism film 121 and/or a second prism film 122, and other structures 124 of the backlight module.

In another possible embodiment, the infrared light source 30 is disposed below the glass cover 130 of the electronic device 2, and is disposed side by side with the liquid crystal panel 110 and the backlight module 120 in the liquid crystal display panel 10.

Alternatively, the infrared light source 30 may be attached obliquely below the glass cover 130. For example, the infrared light source 30 may be attached to the lower side of the display screen 10 by optical glue. Alternatively, the optical glue may be any one of an optical liquid glue or an optical solid glue.

Alternatively, as shown in fig. 19, an infrared light transmitting layer 301 may be disposed between the infrared light source 30 and the glass cover plate, and/or between the infrared light source 30 and the liquid crystal display panel 10, wherein the infrared light transmitting layer 301 is used for transmitting the infrared excitation light and blocking visible light. Optionally, the infrared light transmitting layer 301 may be an infrared light transmitting ink.

Alternatively, as shown in fig. 19, a light blocking foam 302 may be disposed between the infrared light source 30 and the liquid crystal panel 110 in the liquid crystal display panel 10 for blocking visible light.

In addition, in the embodiment of the present application, the infrared light source 30 may be disposed in a non-display area at the edge of the electronic device 2. For example, the electronic device 2 is a mobile phone, the non-display area is a frame area of the mobile phone on which an image is not displayed, and specifically, the infrared light source 30 is disposed in a lower area corresponding to the frame area of the mobile phone on which the image is not displayed.

In some embodiments, the infrared Light source 30 may be a single or multiple Light-Emitting diodes (LEDs). Alternatively, a plurality of infrared light emitting diodes may constitute a strip-shaped infrared light emitting source, which is distributed around the fingerprint detection area 103.

In this application embodiment, carry out optics fingerprint detection through the target fingerprint infrared light that adopts infrared light source to produce, can reduce the interference of screen visible light to infrared light fingerprint detection, and the optics illuminance of balanced infrared light fingerprint image, further improve the quality of fingerprint formation of image.

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

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

In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

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

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

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

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. The utility model provides a fingerprint identification device which characterized in that for set up in liquid crystal display's backlight unit below in order to carry out fingerprint identification under the screen, include:

the fingerprint identification module is arranged below the backlight module;

the backlight module comprises a brightening prism film and a compensating prism film, the compensating prism film is arranged below the brightening prism film in parallel, the compensating prism film faces back to a liquid crystal panel in the liquid crystal display screen, and the brightening prism film faces towards the liquid crystal panel;

the brightening prism film comprises a first brightening prism film side face, the compensating prism film comprises a first compensating prism film side face, and the included angle between the first brightening prism film side face and the plane where the liquid crystal display screen is located is α₁The included angle between the side surface of the first compensation prism film and the plane where the liquid crystal display screen is located is α₂，35°<α₁≤45°，35°<α₂≤45°；

The fingerprint identification module is used for receiving a first target fingerprint optical signal of a first fingerprint optical signal after passing through the first brightening prism film side and the first compensation prism film side so as to perform fingerprint identification, wherein the first target fingerprint optical signal is the same as the first fingerprint optical signal in propagation direction, and the first fingerprint optical signal is an optical signal returned by finger reflection or scattering above the liquid crystal display screen.

2. The fingerprint identification device of claim 1, wherein the material of the brightness enhancing prism film and the compensating prism film are the same, the first compensating prism film side is parallel to the first brightness enhancing prism film side, α₁＝α₂。

3. The fingerprint identification device of claim 1, wherein the brightness enhancing prism film further comprises a second brightness enhancing prism film side, and the compensating prism film further comprises a second compensating prism film side, wherein the second brightness enhancing prism film side and the plane of the liquid crystal display screen form an angle of β degrees₁The included angle between the side surface of the second compensation prism film and the plane where the liquid crystal display screen is located is β₂，β₁≥α₁，β₂≥α₂。

4. Fingerprint recognition device according to claim 3, characterized in that β₁＝90°-α₁。

5. Fingerprint recognition device according to claim 3, characterized in that α₁And β₁The difference value of (2) is less than or equal to a preset threshold value so as to improve the brightness of the liquid crystal display screen.

6. The fingerprint identification device of any one of claims 3-5, wherein the second compensating prism film side is non-parallel to the second brightness enhancing prism film side, β₁≠β₂；

And a second fingerprint optical signal passes through the side surface of the second brightening prism film and the second compensation prism film to form a non-target fingerprint optical signal, the propagation directions of the non-target fingerprint optical signal and the second fingerprint optical signal are different, and the second fingerprint optical signal is an optical signal returned by reflection or scattering of a finger above the liquid crystal display screen.

7. The fingerprint identification device of claim 6, wherein a majority of the second fingerprint light signal is reflected by the second compensation prism film side to form the non-target fingerprint light signal when the second fingerprint light signal passes through the brightness enhancement prism film and then is transmitted to the second compensation prism film side.

8. The fingerprint recognition device according to claim 6, wherein the angles of the first compensation prism film side and the second compensation prism film side are set such that the non-target fingerprint optical signal passing through the second compensation prism film side cannot be received by the fingerprint recognition module, and the first target fingerprint optical signal passing through the first compensation prism film side is received by the fingerprint recognition module for fingerprint recognition.

9. Fingerprint recognition device according to claim 6, characterized in that β₂＝90°。

10. The fingerprint identification device of any one of claims 3-5, wherein the second compensating prism film side is parallel to the second brightness enhancing prism film side, β₁＝β₂；

And a second fingerprint optical signal forms a second target fingerprint optical signal after passing through the side surface of the second brightening prism film and the second compensation prism film, the propagation directions of the second target fingerprint optical signal and the second fingerprint optical signal are the same, and the second fingerprint optical signal is an optical signal returned by reflection or scattering of a finger above the liquid crystal display screen.

11. The fingerprint recognition device of claim 10, wherein the second target fingerprint optical signal passing through the second compensation prism film side and the first target fingerprint optical signal passing through the first compensation prism film side are both received by the fingerprint recognition module for fingerprint recognition.

12. The fingerprint recognition device according to any one of claims 3 to 5, wherein a light absorbing material is disposed on the second compensation prism film side for absorbing the light signal received by the second compensation prism film side.

13. The fingerprint recognition device of any one of claims 1-5, wherein the number of compensating prisms in the compensating prism film is equal to the number of brightness enhancing prisms in the brightness enhancing prism film, and a plurality of compensating prisms in the compensating prism film correspond one-to-one to a plurality of brightness enhancing prisms in the brightness enhancing prism film;

the distance between the ridges of two adjacent compensating prisms in the plurality of compensating prisms is equal to the distance between the ridges of two adjacent brightness enhancing prisms in the plurality of brightness enhancing prisms.

14. The fingerprint recognition device of any one of claims 1-5, wherein a first compensating prism in the compensating prism film corresponds to a first brightness enhancing prism film in the brightness enhancing prism film, the projection of the ridge of the first compensating prism and the ridge of the first brightness enhancing prism on a first plane has an included angle θ, 0 ° ≦ θ ≦ 20 °, and the first plane is a plane parallel to the liquid crystal display.

15. The fingerprint recognition device of any one of claims 1-5, wherein a first compensating prism in the compensating prism film corresponds to a first brightness enhancing prism film in the brightness enhancing prism film, and a projection of a ridge of the first compensating prism onto a first plane is in a projection of a base of the first brightness enhancing prism onto the first plane, the first plane being a plane parallel to the liquid crystal display.

16. The fingerprint recognition device of claim 15, wherein the ridge of the first compensation prism coincides with a projection of the ridge of the first brightness enhancement prism onto the first plane, and the projection of the base of the first compensation prism onto the first plane coincides with the projection of the base of the first brightness enhancement prism onto the first plane.

17. The fingerprint recognition device according to any one of claims 1 to 5, wherein the liquid crystal display comprises two of the brightness enhancement prism films and two of the compensation prism films;

the two brightening prism films and the two compensation prism films are arranged below the liquid crystal display screen in parallel and are positioned on different planes;

the two compensation prism films are respectively arranged below the two brightness enhancement prism films.

18. The fingerprint identification device of claim 17, wherein the projections of the ridges of one of the brightness enhancing prism films to the ridges of one of the brightness enhancing prism films in the two brightness enhancing prism films in the first plane are perpendicular to each other;

the projection of the ridge of one compensating prism in one compensating prism film in the two compensating prism films and the projection of the ridge of one compensating prism in the other compensating prism film on the first plane are mutually vertical, and the first plane is a plane parallel to the liquid crystal display screen.

19. The fingerprint recognition device of claim 17, wherein the distance between each adjacent two of the two brightness enhancement prism films and the two compensation prism films is equal.

20. The fingerprint recognition device according to any one of claims 1 to 5, wherein the fingerprint recognition module comprises:

an optical assembly and a light detecting array,

the optical assembly is used for receiving the first target fingerprint optical signal and transmitting the first target fingerprint optical signal to the optical detection array, and the optical detection array is used for converting the received first target fingerprint optical signal into a fingerprint image signal so as to perform fingerprint identification.

21. The fingerprint recognition device of claim 20, wherein the optical assembly comprises at least one optical lens, the at least one optical lens being a spherical or aspherical lens.

22. The utility model provides a backlight unit which characterized in that is applicable to the electronic equipment who has liquid crystal display, includes: a brightness enhancing prism film and a compensating prism film,

the compensation prism film is arranged below the brightening prism film in parallel, the compensation prism film faces away from a liquid crystal panel in the liquid crystal display screen, and the brightening prism film faces towards the liquid crystal panel;

the brightening prism film comprises a first brightening prism film side face, the compensating prism film comprises a first compensating prism film side face, and the included angle between the first brightening prism film side face and the plane where the liquid crystal display screen is located is α₁The included angle between the side surface of the first compensation prism film and the plane where the liquid crystal display screen is located is α₂，35°<α₁≤45°，35°<α₂≤45°。

23. The backlight module according to claim 22, wherein a first fingerprint optical signal passes through the first brightness enhancement prism film side and the first compensation prism film side to form a first target fingerprint optical signal, the first target fingerprint optical signal is used for fingerprint identification, the first target fingerprint optical signal and the first fingerprint optical signal have the same propagation direction, and the first fingerprint optical signal is an optical signal reflected or scattered and returned by a finger above the liquid crystal display.

24. A backlight module as recited in claim 22, wherein the brightness enhancing prism film and the compensating prism film are made of materialsThe same material, the first compensating prism film side parallel to the first brightness enhancing prism film side, α₁＝α₂。

25. The backlight module of claim 22, wherein the brightness enhancing prism film further comprises a second brightness enhancing prism film side, and the compensating prism film further comprises a second compensating prism film side, wherein the second brightness enhancing prism film side and the plane of the liquid crystal display have an included angle of β₁The included angle between the side surface of the second compensation prism film and the plane where the liquid crystal display screen is located is β₂，β₁≥α₁，β₂≥α₂。

26. A backlight module according to claim 25, wherein β₁＝90°-α₁。

27. A backlight module according to claim 25, wherein α₁And β₁The difference value of (2) is less than or equal to a preset threshold value so as to improve the brightness of the liquid crystal display screen.

28. A backlight module according to any of claims 25 to 27, wherein the second compensating prism film side is non-parallel to the second brightness enhancing prism film side, β₁≠β₂；

And a second fingerprint optical signal passes through the side surface of the second brightening prism film and the second compensation prism film to form a non-target fingerprint optical signal, the propagation directions of the non-target fingerprint optical signal and the second fingerprint optical signal are different, the second fingerprint optical signal is an optical signal returned by reflection or scattering of a finger above the liquid crystal display screen, and the non-target fingerprint optical signal is not used for fingerprint identification.

29. The backlight module as recited in claim 28, wherein a majority of the second fingerprint light signal is reflected by the second compensation prism film side to form the non-target fingerprint light signal when the second fingerprint light signal passes through the brightness enhancement prism film and then is transmitted to the second compensation prism film side.

30. A backlight module according to claim 28, wherein β₂＝90°。

31. A backlight module according to any of claims 25 to 27, wherein the second compensating prism film side is parallel to the second brightness enhancing prism film side, β₁＝β₂；

And a second fingerprint optical signal forms a second target fingerprint optical signal after passing through the side surface of the second brightening prism film and the second compensation prism film, the propagation directions of the second target fingerprint optical signal and the second fingerprint optical signal are the same, the second target fingerprint optical signal is used for fingerprint identification, and the second fingerprint optical signal is an optical signal returned by finger reflection or scattering above the liquid crystal display screen.

32. A backlight module according to any one of claims 25-27, wherein a light absorbing material is disposed on the side of the second compensation prism film for absorbing light signals received by the side of the second compensation prism film.

33. The backlight module according to any of claims 22-27, wherein the number of compensating prisms in the compensating prism film is equal to the number of brightness enhancing prisms in the brightness enhancing prism film, and a plurality of compensating prisms in the compensating prism film correspond one-to-one to a plurality of brightness enhancing prisms in the brightness enhancing prism film;

34. The backlight module according to any of claims 22-27, wherein a first compensating prism in the compensating prism film corresponds to a first brightness enhancing prism film in the brightness enhancing prism film, and the projection of the ridge of the first compensating prism and the ridge of the first brightness enhancing prism on a first plane has an included angle θ, 0 ° ≦ θ ≦ 20 °, and the first plane is a plane parallel to the liquid crystal display panel.

35. A backlight module according to any one of claims 22 to 27, wherein a first compensating prism in the compensating prism film corresponds to a first brightness enhancing prism film in the brightness enhancing prism film, and wherein the projection of the ridge of the first compensating prism onto a first plane is in the projection of the base of the first brightness enhancing prism onto the first plane, which is a plane parallel to the liquid crystal display.

36. A backlight module according to claim 35, wherein the ridge of the first compensating prism coincides with the projection of the ridge of the first brightness enhancing prism onto the first plane, and the projection of the base of the first compensating prism coincides with the projection of the base of the first brightness enhancing prism onto the first plane.

37. A backlight module according to any of claims 22-27, comprising two brightness enhancing prism films and two compensating prism films;

38. A backlight module according to claim 37, wherein the projection of the ridge of one of the brightness enhancing prisms in one of the two brightness enhancing prism films onto the first plane is perpendicular to the ridge of one of the brightness enhancing prisms in the other of the two brightness enhancing prism films;

39. A backlight module as recited in claim 37, wherein the distance between each adjacent two of the two brightness enhancing prism films and the two compensating prism films is the same.

40. An electronic device, comprising: a liquid crystal display screen and a liquid crystal display screen,

the fingerprint identification device of any one of claims 1 to 21, wherein the liquid crystal display comprises a backlight module, and the fingerprint identification device is disposed below the liquid crystal panel.

41. The electronic device of claim 40, further comprising: the infrared light source is used for providing infrared excitation light for fingerprint detection of the fingerprint identification device, the infrared excitation light irradiates at least part of display area of the liquid crystal display screen, and the at least part of display area at least partially covers the fingerprint detection area of the fingerprint identification device;

wherein, infrared light source's infrared excitation light passes through behind the finger reflection or the scattering of fingerprint detection area top pass through backlight unit forms fingerprint infrared light signal, fingerprint identification device is used for receiving fingerprint infrared light signal carries out fingerprint identification.

42. The electronic device of claim 41, wherein the infrared light source is a single or a plurality of infrared light emitting diodes;

the single or multiple infrared light-emitting diodes are distributed around the fingerprint detection area.

43. The electronic device of claim 41 or 42, wherein the infrared light source is disposed below a glass cover of the liquid crystal display and alongside a liquid crystal panel of the liquid crystal display.

44. The electronic device of claim 43, wherein the infrared light source is affixed diagonally below the glass cover plate.

45. The electronic device of claim 43, further comprising: and the infrared light transmission layer is arranged between the infrared light source and the glass cover plate and/or between the infrared light source and the liquid crystal display screen and is used for transmitting the infrared excitation light and blocking visible light.

46. A liquid crystal display panel, comprising:

a backlight module according to any one of claims 22 to 39.

47. An electronic device, comprising: the liquid crystal display of claim 46.