CN211319247U

CN211319247U - Fingerprint identification device, backlight unit, liquid crystal display and electronic equipment

Info

Publication number: CN211319247U
Application number: CN202020150242.XU
Authority: CN
Inventors: 葛丛; 刘杨赞; 蔡斐欣; 何毅; 皮波
Original assignee: Shenzhen Goodix Technology Co Ltd
Current assignee: Shenzhen Goodix Technology 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; CN211319246U

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 screen. This fingerprint identification device is used for setting up and carries out fingerprint identification under the screen in liquid crystal display's backlight unit below, and backlight unit includes first prism membrane and second prism membrane, and first prism membrane and second prism membrane all face liquid crystal display's liquid crystal display panel, and the fingerprint identification device includes: the fingerprint identification module is positioned below the fingerprint detection area in the liquid crystal display screen and used for receiving a first fingerprint optical signal, the first fingerprint optical signal is used for fingerprint identification, the first fingerprint optical signal is an optical signal after passing through one of the prism film side surfaces in the first prism film and one of the prism film side surfaces in the second prism film, and the fingerprint optical signal is an optical signal returned by finger reflection or scattering above the fingerprint detection area; the two base angles in the first prism film are not equal to each other, and the two base angles in the second prism film are not equal to each other.

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 optical imaging of fingerprints of an underscreen fingerprint identification device, so that commercial blocking of underscreen fingerprint identification technology based on the LCD Display screens 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.

In a first aspect, a fingerprint identification device is provided for fingerprint identification under the backlight unit below the setting in order to carry out the screen at liquid crystal display, this backlight unit includes first prism membrane and second prism membrane, and this first prism membrane and this second prism membrane all face this liquid crystal display's liquid crystal display panel, and this fingerprint identification device includes: the fingerprint identification module is positioned at the oblique lower side of a fingerprint detection area in the liquid crystal display screen and used for receiving a first fingerprint optical signal, the first fingerprint optical signal is used for fingerprint identification, wherein the first fingerprint optical signal is an optical signal of the fingerprint optical signal after passing through one prism film side surface in the first prism film and one prism film side surface in the second prism film, and the fingerprint optical signal is an optical signal returned by reflection or scattering of a finger above the fingerprint detection area; two base angles in the first prism film are not equal to each other, two base angles in the second prism film are not equal to each other, two base angles in the first prism film are included angles between the side faces of the two prism films in the first prism film and the plane where the liquid crystal display screen is located, and two base angles in the second prism film are included angles between the side faces of the two prism films in the second prism film and the plane where the liquid crystal display screen is located.

Through the scheme of this application embodiment, improve the prism membrane in liquid crystal display's backlight unit into first prism membrane and second prism membrane, two base angles of this first prism membrane and two base angles of second prism membrane are different, the area of two corresponding prism membrane sides is also different, set up the oblique below in the fingerprint detection area of fingerprint identification module in liquid crystal display, rather than under, aim at making the fingerprint identification module only receive the light signal of a prism membrane side refraction in prism membrane side and the second prism membrane in the first prism membrane, realize the fingerprint identification under the liquid crystal display.

In one possible implementation, the first base angle α in the first prismatic film₁Less than the second base angle α₂，30°≤α₁<45 degrees, the first base angle is the side of the first prism filmThe second base angle is the included angle between the side surface of the second prism film in the first prism film and the plane where the liquid crystal display screen is located.

In one possible implementation manner, the first fingerprint optical signal is an optical signal of the fingerprint optical signal after passing through one of the first prism film side and the second prism film side.

In one possible implementation, the fingerprint identification module is located such that it does not receive the optical signal of the fingerprint after the optical signal passes through the second prism film side and the other prism film side of the second prism film.

In one possible implementation, the third base angle β in the second prismatic film₁Less than fourth base angle β₂，30°≤β₁<And 45 degrees, wherein the third base angle is an included angle between the side surface of the third prism film in the second prism film and the plane where the liquid crystal display screen is located, and the fourth base angle is an included angle between the side surface of the fourth prism film in the second prism film and the plane where the liquid crystal display screen is located.

In one possible implementation, the first fingerprint light signal is a light signal of the fingerprint light signal after passing through the first prism film side and the third prism film side.

In a possible implementation manner, the fingerprint identification module is located such that it cannot receive the optical signal of the fingerprint optical signal after passing through the first prism film side and the fourth prism film.

In a possible implementation manner, the included angle between two prism film side surfaces in the first prism film is the vertex angle gamma of the first prism film₁The included angle between the two prism film sides in the second prism film is the vertex angle gamma of the second prism film₂，70°＜γ₁＜110°，70°＜γ₂＜110°。

In one possible implementation, γ₁＝γ₂＝90°。

In one possible implementation, the first prism film and the second prism film are identical in structure.

In one possible implementation manner, the included angle between the ridge of one prism in the second prism film and the projection of the ridge of one prism in the first prism film on a first plane is theta, and theta is more than or equal to 70 degrees and less than or equal to 90 degrees, wherein the first plane is a plane parallel to the liquid crystal display screen.

In one possible implementation, the fingerprint recognition module includes: an optical assembly and a light detection array; the optical assembly is used for receiving the first 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 first 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.

In one possible implementation, the light detection array includes at least one optical fingerprint sensor.

In a second aspect, a backlight module is provided, which is suitable for an electronic device having a liquid crystal display screen, and comprises: a first prism film and a second prism film, both of which face a liquid crystal panel of the liquid crystal display screen; two base angles in the first prism film are not equal to each other, two base angles in the second prism film are not equal to each other, two base angles in the first prism film are included angles between the side faces of the two prism films in the first prism film and the plane where the liquid crystal display screen is located, and two base angles in the second prism film are included angles between the side faces of the two prism films in the second prism film and the plane where the liquid crystal display screen is located.

In a possible implementation manner, the fingerprint optical signal passes through one of the prism film side surfaces in the first prism film and one of the prism film side surfaces in the second prism film to form a first fingerprint optical signal, the first fingerprint optical signal is used for fingerprint identification, and the fingerprint optical signal is an optical signal returned by reflection or scattering of a finger above the fingerprint detection area.

Through backlight unit in this application, improve original backlight unit, can realize the fingerprint identification function under the liquid crystal display.

In one possible implementation, the first base angle α in the first prismatic film₁Less than the second base angle α₂，30°≤α₁<And 45 degrees, wherein the first base angle is an included angle between the side surface of the first prism film in the first prism film and the plane where the liquid crystal display screen is located, and the second base angle is an included angle between the side surface of the second prism film in the first prism film and the plane where the liquid crystal display screen is located.

In one possible implementation, γ₁＝γ₂＝90°。

In a third aspect, an electronic device is provided, including: the liquid crystal display screen and, according to the first aspect and the fingerprint identification device in the mode that any one of the first aspect may realize, wherein, this liquid crystal display screen includes backlight unit, and this fingerprint identification module sets up in this backlight unit below.

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 module, 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 module; wherein, this first fingerprint light signal includes the infrared excitation light of this infrared light source and passes through this backlight unit's first fingerprint infrared light signal after finger reflection.

In this implementation, through adopting infrared light source to produce first fingerprint infrared light signal to carry out optics fingerprint detection based on this first fingerprint infrared light signal, 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 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.

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

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

By adopting the scheme, the electronic equipment can realize the fingerprint identification function of a large view field under the liquid crystal display screen.

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 schematic cross-sectional view of an enlarged first prism film according to an embodiment of the present disclosure.

FIG. 9 is a schematic diagram of another fingerprint image according to an embodiment of the present application.

Fig. 10 is a cross-sectional view of a relative position relationship between an optical field of view and a fingerprint detection area of a fingerprint identification module according to an embodiment of the present application.

Fig. 11 is a cross-sectional view of the relative position relationship between the optical field of view and the fingerprint detection area of another fingerprint identification module according to an embodiment of the present application.

Fig. 12 is a schematic perspective view illustrating a structure of two prism films in a backlight module according to an embodiment of the present disclosure.

Fig. 13 is a schematic cross-sectional view of fig. 12 in the XZ plane.

FIG. 14 is another schematic cross-sectional view of two prism films in a backlight module according to an embodiment of the present disclosure.

Fig. 15 is a schematic diagram of a fingerprint image according to an embodiment of the present application.

FIG. 16 is a schematic diagram of another fingerprint image according to an embodiment of the present application.

Fig. 17 is an optical field area and a fingerprint detection area top view of a fingerprint identification module in a liquid crystal display according to an embodiment of the present application.

Fig. 18 is an optical view field area and a top view of a fingerprint detection area of another fingerprint identification module in a liquid crystal display according to an embodiment of the present application.

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

FIG. 20 is a schematic cross-sectional view of a second enlarged prism film according to an embodiment of the present application.

Fig. 21 is a schematic diagram of a fingerprint image according to an embodiment of the present application.

Fig. 22 is an optical view field area and a top view of a fingerprint detection area of another fingerprint identification module in a liquid crystal display according to an embodiment of the present application.

Fig. 23 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 image 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 image signals; fingerprint image data can be obtained based on the fingerprint image signal, and fingerprint matching verification can be further performed, so that the optical fingerprint identification function is realized in 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 a fingerprint image 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 vertical prism film and a horizontal prism film as described in fig. 2, are usually disposed, and the two prism films have the same structure, but the directions of the ridges of the prism films are different, and the projection angles of the ridges of the two prism films on the same plane are 90 °, which is a plane parallel to the liquid crystal panel in the 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.

Fig. 3 (a) and 3 (b) show a perspective view and a cross-sectional view of one prism film 1200 in the backlight module 120 in the embodiment of the present application, wherein fig. 3 (b) is a schematic cross-sectional view of fig. 3 (a) in the XZ plane. The prism film 1200 may be any one of the two prism films of fig. 2.

Specifically, the prism film 1200 is formed by regularly arranging a plurality of identical triangular prisms 1210 in a row on a substrate 1220, wherein each triangular prism 1210 is formed by protruding upward from the substrate 1220, each triangular prism 1210 has a structure with 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, an angle between the first side surface 1211 and the horizontal direction is a first base angle α of the triangular prism 1210, and an angle between the second side surface 1212 and the horizontal direction is a 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 side 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.

In order to improve the light condensation effect of the prism film, through experimental data statistics, the vertex angle of the prism film in the prior art is generally 90 degrees, and the light condensation effect of the prism film is optimal under 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 addition, in order to ensure the uniformity of the light condensation of the prism film, that is, to ensure that the light signal at each angle has a good light condensation effect, generally, two base angles in the prism film are generally equal, that is, the areas of two side surfaces of a plurality of triangular prisms in the prism film are the same, and if the vertex angle of the prism film is 90 °, the prism film is composed of a plurality of isosceles right triangular prisms arranged on a substrate.

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 an optical path 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 1200 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 region of the finger, the center region of the finger corresponds to a center region of the fingerprint detection region 103, the fingerprint identification device 20 is disposed below the center region of the fingerprint detection region 103, the third reflected light 153 is refracted by two sides of the prism film 1200 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 at 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, the field of view of the fingerprint identification device 20 is divided into two parts, and two equal parts of the field of view are formed, which results in serious field loss and image distortion.

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.

It should be understood that fig. 4 illustrates the effect of one prism film on the fingerprint light signal, and if two prism films as shown in fig. 2 are included in the liquid crystal display screen, the interference of the other prism film on the fingerprint light signal can also be referred to the above description. If both prism films are formed by isosceles right triangular prisms, the center of the fingerprint image detected by the light detection array 400 forms a dark area as shown in fig. 6, and the field of view of the fingerprint identification device 20 is divided into four parts to form four equal parts of field of view, which results in more serious field loss.

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.

The application provides a fingerprint identification device suitable for liquid crystal display sets up this fingerprint device in fingerprint detection area's oblique below for the refraction light after the side refraction in the prism membrane is received to the fingerprint identification device, and improves the prism membrane structure among liquid crystal display's backlight unit, and the effective visual field of fingerprint light signal is received to the increase fingerprint identification device, thereby forms great area's continuous fingerprint image, realizes fingerprint identification 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 21.

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 disposed below a backlight module of the liquid crystal display to perform fingerprint identification under the display, where the backlight module includes a first prism film.

As shown in fig. 7, the fingerprint recognition device 200 includes:

fingerprint identification module 201, be located the oblique below of fingerprint detection area 103 in liquid crystal display 10 for receive first fingerprint light signal 102, this first fingerprint light signal 101 is used for carrying out fingerprint identification, wherein, this first fingerprint light signal 102 is the light signal of fingerprint light signal 101 through the refraction of first prism membrane side in first prism membrane 121, and this fingerprint light signal 101 is the light signal that returns through the finger reflection or scattering of fingerprint detection area 103 top;

the first base angle in the first prism film 121 is not equal to the second base angle, the first base angle is an included angle between the side surface of the first prism film in the first prism film 121 and the plane where the liquid crystal display screen is located, and the second base angle is an included angle between the side surface of the second prism film in the first prism film 121 and the plane where the liquid crystal display screen is located.

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 (Photo Diode), a Metal Oxide Semiconductor Field Effect Transistor (MOSFET), and the like 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.

In the embodiment of the present application, the fingerprint detection area 103 is a sensing area of the light detection array 400 in the liquid crystal display 10, that is, when a finger of a user presses on the fingerprint detection area 103, an optical signal is reflected or scattered by the finger above the fingerprint detection area 103 and returns to a fingerprint optical signal, the fingerprint detection signal is used to detect fingerprint information of the finger, and the light detection array 400 performs fingerprint imaging on the finger above the fingerprint detection area 103.

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 103 of fingerprint identification module 201 jointly.

In a possible embodiment, 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 the embodiment of the present application, the related features of the liquid crystal display panel 10 and the backlight module 120 can refer to the related descriptions of the liquid crystal display panel 10 and the backlight module 120.

Specifically, the first prism film 121 of the embodiment of the present application is also a prism film structure that is also formed by arranging a plurality of triangular prisms on a substrate, and this first prism film 121 can be understood as a modified prism film structure that is modified and formed on the prism film 1200 described above.

To more clearly illustrate the structure of the modified first prism film 121, fig. 8 shows an enlarged schematic cross-sectional view of the first prism film 121.

As shown in fig. 8, the base of the first prism film 121 is located below, the first prism film side 1211 and the second prism film side 1212 both protrude above the base, the first prism film side 1211 and the second prism film side 1212 both face the liquid crystal panel 110 of the liquid crystal display, and the base of the first prism film 121 is parallel to the plane of the liquid crystal panel 110. In the embodiment of the present application, first side surfaces of the plurality of triangular prisms in the first prism film 121 are referred to as first prism film side surfaces 1211, and second side surfaces of the plurality of triangular prisms are referred to as second prism film side surfaces 1212.

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 a direction perpendicular to the first plane is referred to as a vertical direction. In general, if the lcd panel is horizontally disposed, the first plane is also a horizontal plane, and the vertical direction is a vertical direction.

As shown in fig. 8, an included angle between the side 1211 of the first prism film and the base thereof, i.e. an included angle between the side 1211 of the first prism film and the first plane is a first base angle α₁The included angle between the second prism film side surface 1212 and the substrate thereof, i.e. the included angle between the second prism film side surface 1212 and the first plane, is the second base angle α₂，α₁≠α₂The area of the first prism film side 1211 is not equal to the area of the second prism film side 1212.

In other words, the first prism film 121 is different from the prism film 1200 in that the areas of the two prism film sides of the prism film 1200 are equal and the two base angles are equal, whereas in the embodiment of the present application, the areas of the two prism film sides of the first prism film 121 are different and the two base angles are also different.

Alternatively, α₁＜α₂Correspondingly, the area of the first prism film side 1211 in the first prism film 121 is larger than the area of the second prism film side 1212.

As shown in fig. 8, the first prism film side 1211 receives the optical signal a, and the second prism film side 1212 receives the optical signal b, where the optical signal a and the optical signal b are parallel optical signals, and specifically, both the optical signal a and the optical signal b are optical signals perpendicular to the first plane. In the process of fingerprint identification, the optical signal a and the optical signal b are both returned optical signals after being reflected or scattered by a finger above a fingerprint detection area, and carry fingerprint information. And it can be understood that the light intensity of the light signal is larger in the direction perpendicular to the finger, which is beneficial to improving the quality of the fingerprint image so as to improve the fingerprint identification effect.

The optical signal a is received by the first prism film side 1211, refracted by the first prism film 121, and then emitted as the optical signal c. the optical signal b is received by the second prism film side 1212, refracted by the first prism film 121, and then emitted as the optical signal d. since α₁＜α₂Then, the incident angle of the optical signal a on the side 1211 of the first prism film is smaller than the incident angle of the optical signal b on the side of the second prism film, and the angle between the optical signal c and the vertical direction is smaller than the angle between the optical signal d and the vertical direction, which is also referred to as the exit angle of the optical signal c and the exit angle of the optical signal d and the vertical direction, as known from the law of refraction.

Alternatively, in the embodiment of fig. 8, the optical signal a may be the fingerprint optical signal 101 in fig. 7, and the optical signal c may be the first fingerprint optical signal 102 in fig. 7.

It should be understood that fig. 8 is described by way of example only with reference to the optical signal a and the optical signal b in the vertical direction, and the fingerprint optical signal 101 in the embodiment of the present application may also be an optical signal in another direction received by the side surface of the first prism film.

It can be known from the above description that, for the parallel light signals, the light signals received by the side of the first prism film are refracted by the first prism film, the outgoing light signal angle is smaller, the light signals received by the side of the second prism film are refracted by the first prism film, and the outgoing light signal angle is larger, therefore, if the fingerprint identification module is arranged under the fingerprint detection area, as shown in fig. 9, the dark area appears in the fingerprint image of the fingerprint identification module, the fingerprint image is divided into two parts, the light signals received by the side of the first prism film in the first prism film are refracted, and the imaging area S in the fingerprint identification module is the imaging area S₁The larger the imaging area S of the light signal received by the side surface of the second prism film in the fingerprint identification module after refraction₂Is smaller。

At this moment, if set up fingerprint identification module 201 in fingerprint detection area 103's oblique below, this fingerprint detection area 103 sets up the one side at the optics visual Field (Field of View, FOV) of fingerprint identification module 201 for fingerprint identification module 201 only receives the light signal of first prism membrane side refraction, both can solve the dark space problem in the fingerprint image, realize the fingerprint identification function under the liquid crystal display, also can make the fingerprint identification module have relatively big effective optics visual Field, the fingerprint detection area of corresponding great area.

In the present embodiment, α₁The smaller the area of the first prism film side 1211, the larger the effective optical field of view of the fingerprint identification module, and the better the fingerprint identification effect, but α₁The smaller the effect on the brightness of the liquid crystal display, the greater the effect on the brightness of the liquid crystal display, and in some embodiments, the first bottom corner α is used to balance the brightness of the liquid crystal display with the fingerprint recognition effect₁The value range of (A) is between 30 DEG and 45 DEG, namely α is less than or equal to 30 DEG₁＜45°。

As shown in fig. 8, an included angle between the first prism film side 1211 and the second prism film side 1212 may be referred to as a vertex angle of the first prism film 121, and the vertex angle of the first prism film 121 is γ₁In some embodiments, 70 ° < γ₁＜110°。

Further, in fig. 8, the Pitch (Pitch) between the ridges of two adjacent triangular prisms in the first prism film 121 is P₁Alternatively, P₁Can range from 15 μm to 40 μm, and in some embodiments, P is₁＝24μm。

Optionally, in this embodiment of the application, the optical field of view of the fingerprint identification module 201 may be the optical field of view of the optical component 300 in the fingerprint identification module 201, optionally, the field of view area of the fingerprint identification module 201 is the field of view area of the fingerprint identification module 201 in the liquid crystal display, and the field of view area may be larger than the fingerprint detection area 103.

In addition, in the visual field region of fingerprint identification module 201, except that the subregion is the fingerprint detection area, other regions do not have the finger and cover, for invalid visual field region, consequently, also call this fingerprint identification module 201's effective optics visual field region with the region of this fingerprint detection area 103 and the visual field region coincidence of this fingerprint identification module 201, this fingerprint detection area 103 below spatial region and the visual field region coincidence of this fingerprint identification module 201 call this fingerprint identification module 201's effective optics visual field.

Fig. 10 is a sectional view showing a relative positional relationship between an optical field of view and a fingerprint detection area of the fingerprint recognition module 201.

As shown in fig. 10, the fingerprint identification module 201 is disposed at the lower left of the fingerprint detection area 103, and the dotted line above the fingerprint identification module 201 represents the optical field of view thereof, which is related to the structure and optical parameters of the optical component in the fingerprint identification module. The optical viewing field may form a circular viewing field area on the liquid crystal panel 110, wherein the fingerprint detection area 103 is located on the right side of the circular viewing field area, and a fingerprint optical signal reflected or scattered by a finger above the fingerprint detection area 103 is received by the fingerprint identification module 201 after being refracted by the first prism film side surface of the first prism film 121. The fingerprint optical signal (e.g., the optical signal 103 in fig. 10) reflected or scattered by the finger above the fingerprint detection area 103 is refracted by the side surface of the second prism film in the first prism film 121 (e.g., the optical signal 104 in fig. 10) and cannot be received by the fingerprint identification module 201.

FIG. 11 is a sectional view showing the relative position relationship between the field of view and the fingerprint detection area of another fingerprint recognition module.

Fig. 11 shows, fingerprint identification module 201 sets up in the right side below of fingerprint detection area 103, and wherein, fingerprint detection area 103 is located the left side of the optics visual field of fingerprint identification module 201, and fingerprint optical signal after fingerprint detection area 103 top finger reflection or scattering is received by the fingerprint identification module after the refraction of the second prism membrane side in first prism membrane 121. The fingerprint optical signal (for example, the optical signal 101 in fig. 11) reflected or scattered by the finger above the fingerprint detection area 103 is refracted by the first prism film side surface of the first prism film 121 (for example, the optical signal 102 in fig. 11) and cannot be received by the fingerprint identification module.

Because the refraction angle of different sides to light signal in first prism membrane 121 is different, fingerprint detection area 103 in fig. 11 compares with fingerprint detection area 103 in fig. 10, the area is less, if the fingerprint identification module sets up according to fig. 11, then the fingerprint identification module only receives the light signal of second prism membrane side refraction in the first prism membrane, though also can solve the dark space problem, but the effective optics visual field of fingerprint identification module this moment is less relatively, also can only correspond the fingerprint detection area of less area, the fingerprint identification effect is not good.

Therefore, in this application embodiment, set up fingerprint identification module 201 in fingerprint detection area 103's oblique below, rather than under, aim at making fingerprint identification module 201 only receive the great first prism membrane side refraction's of area light signal, and the less second prism membrane side refraction's of area light signal, improve the effective visual field of fingerprint identification module, carry out fingerprint identification to the finger of the fingerprint detection area top of great area.

In addition, because the area of first prism membrane side is greater than the area of second prism membrane side again, the light signal that first prism membrane side can receive is more, and the light intensity is great, outside the effective field of view that improves the fingerprint identification module, also is favorable to improving the quality of fingerprint image.

The structure of the first prism film 121 and the position of the fingerprint identification module 201 when only one first prism film 121 is included in the backlight module are described above with reference to fig. 7 to 11.

Optionally, the backlight module may further include two prism films, i.e., two prism films with different directions as shown in fig. 2.

Optionally, the projection angle of the ridges of the two prism films on the first plane is theta, theta is more than or equal to 70 degrees and less than or equal to 90 degrees, and the ridges of the prism films can be the ridges of any prism in the ridge films.

Alternatively, the distance between the two prism films may be smaller than 1 μm or any other value, which is not limited in the embodiments of the present application.

In addition, in the embodiment of the present application, other optical film layers in the backlight module may be disposed between the two prism films, and other film layers may not be disposed between the two prism films.

In one embodiment, one of the two prism films may have the same structure as the modified first prism film 121 described above, and the other prism film may have the same structure as the unmodified original prism film 1200 (an example of a second prism film).

Fig. 12 is a schematic perspective view showing the three-dimensional structure of two prism films in the backlight module. Fig. 13 shows a schematic cross-sectional view of the perspective view of fig. 12 in the XZ plane. As shown in fig. 12 and 13, the upper prism film is the first prism film 121, and the lower prism film is the prism film 1200. Of course, in the present embodiment, for example, as shown in fig. 14, the prism film 1200 may be located above the first prism film 121.

Under the prism membrane structure shown in fig. 12 and 13, if the fingerprint identification module is arranged below the fingerprint detection area, the fingerprint light signal passing through the first prism membrane 121 is refracted to two parts, wherein the fingerprint image area formed by the first fingerprint light signal refracted through the side surface of the first prism membrane 121 is larger than the fingerprint image area formed by the second fingerprint light signal refracted through the side surface of the second prism membrane 121. After being refracted by the first prism film 121, as shown in fig. 15, the fingerprint image is divided into two parts in the Y direction, forming a left part and a right part, and the areas of the two parts are different. The light signal refracted by the first prism film 121 passes through the two prism film sides of the prism film 1200 again and is refracted into two parts, and the fingerprint image is divided into two parts in the X direction again to form four parts.

In the prism film structure shown in fig. 14, if the fingerprint recognition module is disposed below the fingerprint detection area, similar to the above case, as shown in fig. 16, after being refracted by the prism film 1200, the fingerprint image is divided into two parts in the X direction, and the two parts are equally divided into the left part and the right part. The light signal refracted by the prism film 1200 passes through the two prism film side surfaces of the first prism film 121 again, and is refracted into two parts, and the fingerprint image is divided into two parts in the Y direction again, and divided into four parts having different areas.

Thus, in both cases, the fingerprint image is divided into 2 larger area regions and 2 smaller area regions, where the two larger area regions correspond to the optical signals refracted through the first one of the first prism films.

In order to remove the image dark space, improve the effective visual field of fingerprint identification module, need remove the fingerprint identification module, and the fingerprint identification module can receive the optical signal after the refraction of prism membrane side in first prism membrane side and the prism membrane in the first prism membrane, and at this moment, fingerprint detection area is located the one corner of the visual field of fingerprint identification module.

In particular, in the above, in the case that the backlight module has only one first prism film, the fingerprint identification module is moved to one side from right below the fingerprint detection area, and the fingerprint identification module can be translated along the X direction of the plane where the fingerprint identification module is located. In this application embodiment, except that carry out the translation with the fingerprint identification module from fingerprint detection area's orientation X under, still need carry out the translation with the fingerprint identification module to the Y direction, after the removal, fingerprint detection area is located the angle of the visual field of fingerprint identification module, and wherein, X direction and Y direction are the orientation of mutual vertically in the coplanar.

For example, fig. 17 shows a top view of the optical field area and the fingerprint detection area of the fingerprint identification module in the liquid crystal display screen under the condition that the backlight module only includes one first prism film 121. Fig. 18 shows a top view of the optical viewing area and the fingerprint detection area of the fingerprint identification module in the liquid crystal display screen under the condition that the backlight module includes the first prism film 121 and the original prism film 1200.

In fig. 17 and 18, the circular dotted line represents the optical viewing field area of the fingerprint recognition module in the liquid crystal display, and comparing fig. 17 and 18, it can be seen that the area of the fingerprint detection area 103 is reduced by half compared to the case where the backlight module has only one first prism film, in the case where the backlight module has the first prism film and the original prism film, that is, the effective viewing field of the fingerprint recognition module is also reduced by half.

However, in this mode, since one prism film is added, the luminance of the liquid crystal display panel is improved as compared with the case of one prism film.

In order to comprehensively consider the brightness of the liquid crystal display screen and the effective field of view of the fingerprint identification module, in another embodiment, the two prism films can be improved prism films.

Alternatively, both of the prism films may have the same structure as the modified first prism film 121, i.e., the same structure as the two prism films.

Alternatively, one of the two prism films may have the same structure as the modified first prism film 121, and the other prism film may also have a modified prism film, i.e., the prism films have different side areas of the two prism films, but the prism film has a different structure from the first prism film.

For convenience of description, in the following embodiments, one of the prism films in the backlight module is the first prism film 121, and the other prism film is referred to as the second prism film 122. Optionally, the second prism film 122 is disposed in parallel below the first prism film 121.

The second prism film 122 of the embodiment of the present application is also a prism film structure, which is also formed by arranging a plurality of triangular prisms on a substrate, and the second prism film 122 can also be understood as an improved prism film structure formed by improving the prism film 1200.

Fig. 19 is a schematic structural diagram of another fingerprint identification device 200 provided in this embodiment of the present application, which is suitable for an electronic apparatus having a liquid crystal display, and is arranged below a backlight module of the liquid crystal display to perform fingerprint identification under the display, where the backlight module includes a first prism film and a second prism film, and the first prism film and the second prism film are both facing a liquid crystal panel of the liquid crystal display.

As shown in fig. 19, the fingerprint recognition device 200 includes:

fingerprint identification module 201, be located in the oblique below of fingerprint detection area 103 in liquid crystal display 10 for receive first fingerprint light signal, this first fingerprint light signal is used for carrying out fingerprint identification, and wherein, first fingerprint light signal is the light signal behind one of them prism film side in fingerprint light signal passes through one of them prism film side in first prism film 121 and the second prism film 122, and this fingerprint light signal is for passing through the light signal that finger reflection or scattering above the fingerprint detection area and return;

the two base angles in the first prism film 121 are not equal to each other, and the two base angles in the second prism film 122 are not equal to each other, the two base angles in the first prism film 121 are included angles between the side surfaces of the two prism films in the first prism film 121 and the plane where the liquid crystal display screen 10 is located, and the two base angles in the second prism film 122 are included angles between the side surfaces of the two prism films in the second prism film 122 and the plane where the liquid crystal display screen 10 is located.

FIG. 20 shows an enlarged cross-sectional view of the second prismatic film 122.

As shown in fig. 20, the second prism film 122 has a lower base, a third prism film side 1221 and a fourth prism film side 1222 both protruding upward of the base, the third prism film side 1221 and the fourth prism film side 1222 both facing the liquid crystal panel 110 of the liquid crystal display, and the base of the second prism film 122 is parallel to the plane of the liquid crystal panel 110. In the present embodiment, a first side surface of the plurality of triangular prisms in the second prism film 122 is referred to as a third prism film side surface 1221, and a second side surface of the plurality of triangular prisms is referred to as a fourth prism film side surface 1222.

As shown in FIG. 20, the angle between the third prism film side surface 1221 and its base, i.e., the angle between the third prism film side surface 1221 and the first plane, is the third base angle β₁The angle between the fourth prism film side 1222 and the substrate, i.e. the angle between the fourth prism film side 1222 and the first plane is the fourth bottom angle β₂，β₁≠β₂The area of the third prism film side 1221 is not equal to the area of the fourth prism film side 1222.

Alternatively, β₁＜β₂Correspondingly, the third prism film side surface of the second prism film 1221221 is larger in area than the fourth prism film side 1222.

In the present embodiment, β₁The smaller the area of the third prism film side 1221, the larger the effective optical field of view of the fingerprint identification module, and the better the fingerprint identification effect, but β₁The smaller the influence on the brightness of the liquid crystal display, the larger the influence on the brightness of the liquid crystal display, and further, in some embodiments, the third base angle β 1 ranges from 30 ° to 45 °, i.e., 30 ° < β ° in order to balance the brightness of the liquid crystal display and the fingerprint recognition effect₁Alternatively, β₁＝α₁。

As shown in fig. 20, the angle between the third prism film side surface 1221 and the fourth prism film side surface 1222 may be referred to as a vertex angle of the second prism film 122, and the vertex angle of the second prism film 122 is γ₂In some embodiments, 70 ° < γ₂< 110. Alternatively, γ₁＝γ₂。

Optionally, in some embodiments, γ₁＝γ₂With this embodiment, while fingerprint recognition is achieved, the brightness of the liquid crystal display screen can be maximally ensured.

Further, in fig. 20, the Pitch (Pitch) between the ridges of two adjacent triangular prisms in the second prism film 122 is P₂Alternatively, P₁Can range from 15 μm to 40 μm, and in some embodiments, P is₂＝P₁24 μm, and in other embodiments, P₂And P₁The Pitch values of the two prism films may not be particularly limited in this embodiment.

If the second prism film 122 is disposed under the first prism film 121, a partial region of the second prism film 122 receives the optical signal, such as the optical signal c, refracted by the first prism film side 1211 of the first prism film 121, and another partial region receives the optical signal, such as the optical signal d, refracted by the second prism film side 1212 of the first prism film 121.

As shown in FIG. 20, third prism film side 1221 on second prism film 122 receivesOptical signal c₁Fourth prism film side 1222 to receive optical signal c₂The optical signal c₁And an optical signal c₂Are optical signals refracted through the first prism film side 1211 of the first prism film 121.

Optical signal c₁The light is received by the third prism film side 1221, refracted by the second prism film 122, and then emitted as an optical signal e. Optical signal c₂After being received by the fourth prism film side 1222 and refracted by the second prism film 122, the optical signal f is emitted as β₁＜β₂Then optical signal c₁The angle of incidence on the third prism film side 1221 is less than the optical signal c₂The angle of incidence on the side of the second prism film is smaller than the angle of incidence of the optical signal f with respect to the vertical direction, as known from the law of refraction.

Optionally, in an embodiment, the optical signal e in fig. 20 may be the first fingerprint optical signal 102 in fig. 7, and is received by the fingerprint identification module 201 for fingerprint identification.

Optionally, in another embodiment, the optical signal f in fig. 20 may also be the first fingerprint optical signal 102 in fig. 7, and is received by the fingerprint identification module 201 for fingerprint identification.

In other words, in the embodiment of the present application, the first fingerprint light signal is a light signal of the fingerprint light signal after passing through one of the first prism film side 1211 and the second prism film 122 of the first prism film 121. The fingerprint identification module 201 is located such that it cannot receive the optical signal of the fingerprint after passing through the second prism film side 1212 of the first prism film 121 and the other prism film side of the second prism film 122.

It should be understood that fig. 20 described above only shows the optical signal c in the vertical direction₁And c₂By way of example, the direction of the fingerprint light signal received by the third prism film side is not particularly limited in the embodiments of the present application, and may include a fingerprint light signal in any direction.

Similar to the above imaging analysis of the optical signal passing through two sides in the first prism film, the optical signal received by the third prism film sideThe outgoing light signal angle is small after the signal is refracted by the second prism film, and the outgoing light signal angle is large after the light signal received by the side face of the fourth prism film is refracted by the second prism film. If fingerprint identification module sets up under fingerprint detection area, on the basis of the fingerprint image of fig. 9, divide into four once more with fingerprint image, form the fingerprint image in fig. 21. Wherein S is₁Corresponding to the refracted optical signal, S, passing through the first prism film side 1211 and the third prism film side 1221₂Corresponding to the refracted optical signal, S, passing through the second and third

prism film sides

1212 and 1221₃Corresponding to the optical signal S after refraction through the first prism film side 1211 and the fourth prism film side 1222₄Corresponds to the refracted optical signal passing through the second prism film side 1212 and the fourth prism film side 1222.

At this time, if the fingerprint identification module is disposed at the oblique lower side of the fingerprint detection area, the fingerprint detection area is disposed at one corner of the optical view field of the fingerprint identification module, so that the fingerprint identification module receives only the optical signals refracted by the first prism film side surface and the third prism film side surface (corresponding to S in fig. 20)₁) And can not receive the light signal of other prism membrane side refractions, both can solve the dark space problem in the fingerprint image, can realize the fingerprint identification function under the liquid crystal display, also can make the fingerprint identification module have the effective optics visual field of relative big, the fingerprint detection area of corresponding great area.

Fig. 22 shows a top view of the optical field area and the fingerprint detection area of the fingerprint identification module under the condition that the backlight module includes the first prism film 121 and the second prism film 121.

In fig. 22, the circular dotted line represents the optical viewing field area of the fingerprint recognition module in the liquid crystal panel, and comparing fig. 18 and fig. 22, it can be seen that the area of the fingerprint detection area 103 is increased in the case that the backlight module includes the first prism film 121 and the second prism film 122, compared to the case that the backlight module includes the first prism film 121 and the original prism film 1200.

Consequently, this application embodiment of sampling, when taking into account liquid crystal display's luminance, can also further increase the effective visual field of fingerprint identification module, increase the area of fingerprint detection area 103 to gather the fingerprint image of great area, improve the fingerprint identification performance under the liquid crystal display.

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;

optionally, the relevant features of the backlight module 120 in the embodiment of the present application may be referred to in the relevant description of the backlight module 120 in the above embodiment.

Specifically, the backlight assembly 120 includes a first prism film 121 and a second prism film 122, both the first prism film 121 and the second prism film 122 facing the liquid crystal panel of the liquid crystal display panel;

two base angles in the first prism film 121 are not equal to each other, and two base angles in the second prism film 122 are not equal to each other, two base angles in the first prism film 121 are included angles between the side surfaces of the two prism films in the first prism film 121 and a plane where the liquid crystal display screen is located, and two base angles in the second prism film 122 are included angles between the side surfaces of the two prism films in the second prism film 122 and the plane where the liquid crystal display screen is located.

In one embodiment, the fingerprint light signal passes through one of the prism film sides of the first prism film 121 and one of the prism film sides of the second prism film 122 to form a first fingerprint light signal, which is used for fingerprint identification, and the fingerprint light signal is reflected or scattered by a finger above the fingerprint detection area and returns.

Optionally, the first base angle α in the first prism film 121₁Less than the second base angle α₂，30°≤α₁<The first base angle is an included angle between the side 1211 of the first prism film 121 and the plane where the liquid crystal display screen is located, and the second base angle is an included angle between the side 1212 of the second prism film 121 and the plane where the liquid crystal display screen is located.

In one embodiment, the first fingerprint light signal is a light signal of the fingerprint light signal after passing through one of the first prism film side 1211 and the second prism film 122.

Optionally, a third base angle β in the second prismatic film 122₁Less than fourth base angle β₂，30°≤β₁<45 degrees, the third base angle is the included angle between the third prism film side 1221 in the second prism film 122 and the plane where the liquid crystal display screen is located, and the fourth base angle is the included angle between the fourth prism film side 1222 in the second prism film 122 and the plane where the liquid crystal display screen is located.

In one embodiment, the first fingerprint light signal is a light signal after the fingerprint light signal passes through the first prism film side 1211 and the third prism film side 1221.

Optionally, the included angle between two prism film sides in the first prism film 121 is the vertex angle γ of the first prism film 121₁The included angle between the two prism film sides in the second prism film 122 is the vertex angle γ of the second prism film 122₂，70°＜γ₁＜110°，70°＜γ₂< 110. Alternatively, γ₁＝γ₂＝90°。

In some embodiments, the first and

second prism films

121 and 122 have the same structure.

Optionally, the projection angle between the ridge of one prism in the second prism film 122 and the ridge of one prism in the first prism film 121 on the first plane is theta, and theta is more than or equal to 70 degrees and less than or equal to 90 degrees, wherein the first plane is a plane parallel to the liquid crystal display screen.

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

As shown in fig. 23, 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.

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. 23, 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 10, and is disposed obliquely above the backlight module 120 of the liquid crystal display 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. 23, 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. 23, 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, through adopting infrared light source to produce first fingerprint infrared light signal to carry out optics fingerprint detection based on this first fingerprint infrared light signal, 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 for set up in liquid crystal display's backlight unit below in order to carry out fingerprint identification under the screen, backlight unit includes first prism membrane and second prism membrane, first prism membrane with the second prism membrane all faces liquid crystal display's liquid crystal display panel, wherein, second prism membrane parallel arrangement is in the below of second prism membrane, the fingerprint identification device includes:

the fingerprint identification module is positioned obliquely below a fingerprint detection area in the liquid crystal display screen and used for receiving a first fingerprint optical signal, the first fingerprint optical signal is used for fingerprint identification, the first fingerprint optical signal is an optical signal of the fingerprint optical signal after passing through one of the side surfaces of the first prism film and one of the side surfaces of the second prism film, and the fingerprint optical signal is an optical signal returned by reflection or scattering of a finger above the fingerprint detection area;

two base angles in the first prism film are not equal to each other, two base angles in the second prism film are not equal to each other, two base angles in the first prism film are included angles between two prism film side surfaces in the first prism film and a plane where the liquid crystal display screen is located, and two base angles in the second prism film are included angles between two prism film side surfaces in the second prism film and the plane where the liquid crystal display screen is located.

2. The fingerprint recognition device of claim 1, wherein the first base angle α in the first prismatic film₁Less than the second base angle α₂，30°≤α₁<And 45 degrees, the first base angle is an included angle between the side surface of the first prism film in the first prism film and the plane where the liquid crystal display screen is located, and the second base angle is an included angle between the side surface of the second prism film in the first prism film and the plane where the liquid crystal display screen is located.

3. The fingerprint recognition device of claim 2, wherein the first fingerprint light signal is a light signal of the fingerprint light signal after passing through one of the first prism film side and the second prism film side.

4. The fingerprint recognition device of claim 3, wherein the fingerprint recognition module is positioned such that it does not receive the fingerprint light signal after passing through the second prism film side and the other prism film side.

5. The fingerprint recognition device of claim 3, wherein the third base angle β in the second prismatic film₁Less than fourth base angle β₂，30°≤β₁<And 45 degrees, the third base angle is an included angle between the side surface of the third prism film in the second prism film and the plane where the liquid crystal display screen is located, and the fourth base angle is an included angle between the side surface of the fourth prism film in the second prism film and the plane where the liquid crystal display screen is located.

6. The fingerprint recognition device of claim 5, wherein the first fingerprint light signal is a light signal of the fingerprint light signal after passing through the first prism film side and the third prism film side.

7. The fingerprint identification device of claim 6, wherein the fingerprint identification module is positioned such that it does not receive the light signal of the fingerprint after passing through the first prism film side and the fourth prism film.

8. The fingerprint recognition device according to any one of claims 1 to 7, wherein the included angle between two prism film side surfaces in the first prism film is the vertex angle γ of the first prism film₁The included angle of the side surfaces of two prism films in the second prism film is the vertex angle gamma of the second prism film₂，70°＜γ₁＜110°，70°＜γ₂＜110°。

9. The fingerprint recognition device of claim 8, wherein γ is γ₁＝γ₂＝90°。

10. The fingerprint recognition device according to any one of claims 1 to 7, wherein the first prism film and the second prism film are identical in structure.

11. The fingerprint recognition device according to any one of claims 1 to 7, wherein the projection of the ridge of one of the prisms of the second prism film to the ridge of one of the prisms of the first prism film on a first plane is at an angle θ, wherein θ is 70 ° or more and 90 ° or less, and wherein the first plane is a plane parallel to the liquid crystal display.

12. The fingerprint recognition device of any one of claims 1-7, wherein the fingerprint recognition module comprises: an optical assembly and a light detection array;

the optical assembly is used for receiving the first 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 first fingerprint optical signal into a fingerprint image signal so as to perform fingerprint identification.

13. The fingerprint recognition device of claim 12, wherein the optical assembly comprises at least one optical lens, the at least one optical lens being a spherical or aspherical lens.

14. The fingerprint recognition device of claim 12, wherein the light detection array comprises at least one optical fingerprint sensor.

15. The utility model provides a backlight unit which characterized in that is applicable to the electronic equipment who has liquid crystal display, includes: the liquid crystal display panel comprises a first prism film and a second prism film, wherein the first prism film and the second prism film face to a liquid crystal panel of the liquid crystal display panel, and the second prism film is arranged below the second prism film in parallel;

16. The backlight module according to claim 15, wherein a fingerprint optical signal passes through one of the prism film sides of the first prism film and one of the prism film sides of the second prism film to form a first fingerprint optical signal, the first fingerprint optical signal is used for fingerprint identification, and the fingerprint optical signal is an optical signal returned by reflection or scattering of a finger above the fingerprint detection area.

17. A backlight module as recited in claim 16, wherein the first base angle α in the first prismatic film₁Less than the second base angle α₂，30°≤α₁<And 45 degrees, the first base angle is an included angle between the side surface of the first prism film in the first prism film and the plane where the liquid crystal display screen is located, and the second base angle is an included angle between the side surface of the second prism film in the first prism film and the plane where the liquid crystal display screen is located.

18. The backlight module as claimed in claim 17, wherein the first fingerprint light signal is a light signal of the fingerprint light signal passing through one of the first prism film side and the second prism film side.

19. A backlight module as recited in claim 18, wherein the third base angle β in the second prismatic film₁Less than fourth base angle β₂，30°≤β₁<45 degrees, the third base angle is the included angle between the side surface of the third prism film in the second prism film and the plane where the liquid crystal display screen is located, and the fourth base angle isAnd the side face of a fourth prism film in the second prism film forms an included angle with the plane where the liquid crystal display screen is located.

20. The backlight module according to claim 19, wherein the first fingerprint light signal is a light signal of the fingerprint light signal after passing through the first prism film side and the third prism film side.

21. The backlight module according to any one of claims 15-20, wherein the included angle between two prism film sides in the first prism film is the vertex angle γ of the first prism film₁The included angle of the side surfaces of two prism films in the second prism film is the vertex angle gamma of the second prism film₂，70°＜γ₁＜110°，70°＜γ₂＜110°。

22. A backlight module according to claim 21, wherein γ is₁＝γ₂＝90°。

23. A backlight module according to any one of claims 15-20, wherein the first and second prismatic films are identical in structure.

24. The backlight module according to any one of claims 15-20, wherein the projection of the ridge of one of the prisms of the second prismatic film onto the ridge of one of the prisms of the first prismatic film onto a first plane is at an angle θ, wherein θ is 70 ° or more and 90 ° or less, and wherein the first plane is a plane parallel to the liquid crystal display panel.

25. 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 14, wherein the liquid crystal display comprises a backlight module, and the fingerprint identification module is disposed below the backlight module.

26. The electronic device of claim 25, further comprising: the infrared light source is used for providing infrared excitation light for fingerprint detection of the fingerprint identification module, the infrared excitation light irradiates at least part of display area of the liquid crystal display screen, and at least part of the display area at least partially covers the fingerprint detection area of the fingerprint identification module;

the first fingerprint optical signal comprises a first fingerprint infrared optical signal of the backlight module, wherein the infrared excitation light of the infrared light source passes through the first fingerprint infrared optical signal after being reflected by a finger.

27. The electronic device of claim 26, 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.

28. The electronic device of claim 26 or 27, 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.

29. The electronic device of claim 28, wherein the infrared light source is affixed diagonally below the glass cover plate.

30. The electronic device of claim 28, 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.

31. A liquid crystal display panel, comprising:

a backlight module according to any one of claims 15 to 24.

32. An electronic device, comprising: the liquid crystal display of claim 31.