CN111095288A

CN111095288A - Optical fingerprint identification device under screen, system and liquid crystal display screen

Info

Publication number: CN111095288A
Application number: CN201980004394.9A
Authority: CN
Inventors: 杜灿鸿; 蒋方林
Original assignee: Shenzhen Goodix Technology Co Ltd
Current assignee: Shenzhen Goodix Technology Co Ltd
Priority date: 2019-12-02
Filing date: 2019-12-02
Publication date: 2020-05-01
Anticipated expiration: 2039-12-02
Also published as: WO2021108968A1; CN111095288B

Abstract

The application provides optical fingerprint identification device and system under screen, liquid crystal display. Optical fingerprint identification device includes under the screen: the detection light source, the light path guide structure and the optical fingerprint sensor are arranged below the backlight module; the detection light source is used for emitting detection light, the detection light irradiates a finger through the liquid crystal display screen, and the light path guide structure is used for guiding the fingerprint detection light which is reflected by the finger, carries fingerprint information and penetrates through the liquid crystal display screen to the optical fingerprint sensor; the optical fingerprint sensor is used for acquiring fingerprint information of the finger according to the fingerprint detection light; at least one of the detection light and the fingerprint detection light penetrates through the polarization layer, the polarization layer is used for filtering S waves in the detection light and/or the fingerprint detection light, and the polarization layer is positioned above the optical fingerprint identification device under the screen; the polarization direction of the polarization layer is the same as that of the first reflective polarization film layer. The accuracy rate of fingerprint identification is high.

Description

Optical fingerprint identification device under screen, system and liquid crystal display screen

Technical Field

The application relates to a fingerprint identification technology, in particular to an optical fingerprint identification device and system under a screen and a liquid crystal display screen.

Background

With the development of display technology, the identity recognition technology is continuously innovated, changed and developed, and especially the fingerprint recognition technology of mobile phone terminals has become the mainstream pillar of identity recognition.

A Liquid Crystal Display (LCD) screen has many advantages such as thin body, power saving, no radiation, and is widely used in electronic products such as televisions, computers, and mobile phones. LCD screens typically require a backlight module to illuminate the liquid crystal panel to display the image. When applying optical fingerprint identification technique under the screen to liquid crystal display who has reflective polarizing film in, fingerprint identification module under the screen generally includes: the fingerprint detection light formed by reflection on the finger penetrates through the liquid crystal display screen and enters the lens group, the lens group converges the fingerprint detection light and forms a fingerprint image on the fingerprint identification chip, and the fingerprint image is collected and identified by the fingerprint identification chip.

However, in the fingerprint identification module, the lcd includes the reflective polarizing film, and no matter the detection light emitted by the light source or the fingerprint detection light formed on the finger passes through the reflective polarizing film, about 50% reflection and 50% transmission are generated, and when the reflection light falls within the field range of the lens set, the interference is caused to the image of the fingerprint image, resulting in low fingerprint identification accuracy.

Disclosure of Invention

The application provides an optical fingerprint identification device under screen, a system and a liquid crystal display screen, which aim to solve the problem that the fingerprint identification accuracy rate is not high in the prior art.

The application provides an optical fingerprint identification device under a screen, which is suitable for a liquid crystal display screen with a display module and a backlight module, wherein a first reflective polarizing film layer is arranged between the display module and the backlight module,

optical fingerprint identification device includes under the screen: the detection light source, the light path guide structure and the optical fingerprint sensor are arranged below the backlight module; the detection light source is used for emitting detection light, the detection light irradiates a finger through the liquid crystal display screen, and the light path guide structure is used for guiding the fingerprint detection light which is reflected by the finger, carries fingerprint information and penetrates through the liquid crystal display screen to the optical fingerprint sensor; the optical fingerprint sensor is used for acquiring fingerprint information of the finger according to the fingerprint detection light; at least one of the detection light and the fingerprint detection light penetrates through the polarization layer, the polarization layer is used for filtering S waves in the detection light and/or the fingerprint detection light, and the polarization layer is positioned above the optical fingerprint identification device under the screen; the polarization direction of the polarization layer is the same as that of the first reflective polarization film layer.

In a specific embodiment of the present application, the polarization layer is disposed on a light emitting surface of the backlight module, or on a back surface of the backlight module away from the light emitting surface, or in the backlight module.

In a specific embodiment of the present application, the backlight module includes a back plate assembly for fixing the light guide plate, and the polarizing layer is disposed on the back plate assembly.

In a specific embodiment of the application, the polarizing layer is at least positioned above the detection light source, so that the detection light is irradiated to the finger through the polarizing layer and the liquid crystal display screen;

and the position of the backboard component corresponding to the detection light source is provided with a first light through hole, and the polarization layer above the detection light source at least covers the first light through hole.

In a specific embodiment of the present application, the polarizing layer is at least located above the optical path guiding structure, so that the fingerprint detection light is incident into the optical path guiding structure through the polarizing layer;

and the position of the backboard component corresponding to the light path guiding structure is provided with a second light through hole, and the polarizing layer at least covers the second light through hole.

In a specific embodiment of the present application, the optical path guiding structure includes an optical lens layer, the optical lens layer includes one or more aspheric lenses for converging the fingerprint detection light onto the optical fingerprint sensor, and the polarizing layer above the optical path guiding structure covers at least a field of view range of the optical lens layer.

In the specific implementation mode of the application, a second reflective polarizing film layer and a diffuse reflection layer are also arranged,

the second reflective polarizing film layer is arranged between the detection light source and the polarizing layer above the detection light source; the detection light source is positioned between the diffuse reflection layer and the second reflection type polarizing film layer.

In a specific embodiment of the present application, the second reflective polarizing film layer is disposed on the backplane assembly, and the second reflective polarizing film layer covers at least the first light passing hole.

In the specific implementation manner of the application, the detection light source is arranged on the flexible circuit board FPC, and the diffuse reflection layer is arranged on one surface, facing the detection light source, of the flexible circuit board FPC.

In a specific embodiment of the present application, the diffuse reflection layer is a white ink layer or a silver powder layer.

In the specific implementation mode of the application, the detection light source, the light path guiding structure and the optical fingerprint sensor are arranged on the middle frame of the liquid crystal display screen.

The application provides an optical fingerprint identification system under screen, including optical fingerprint identification device under liquid crystal display and foretell screen, optical fingerprint identification device sets up in liquid crystal display's below under the screen for detect the fingerprint information of the finger of liquid crystal display top.

The application provides a support liquid crystal display of fingerprint identification function under screen, liquid crystal display below is equipped with foretell optics fingerprint identification device under screen, and liquid crystal display includes: the display module comprises a display module, a backlight module and a first reflective polarizing film layer positioned between the display module and the backlight module;

further comprising: the polarization layer is arranged above the optical fingerprint identification device under the screen, at least one of the detection light and the fingerprint detection light penetrates through the polarization layer, and the polarization layer is used for filtering S waves in the detection light and/or the fingerprint detection light;

the polarization direction of the polarization layer is the same as that of the first reflective polarization film layer.

The application still provides an optical fingerprint identification device under screen, is applicable to the liquid crystal display who has display module assembly and backlight unit, wherein, sets up first reflection type polarisation rete between display module assembly and the backlight unit, and optical fingerprint identification device includes under the screen: the detection light source, the light path guide structure and the optical fingerprint sensor are arranged below the backlight module; the detection light source is used for emitting detection light, part of the detection light is irradiated to the finger through the second reflection type polarizing film layer, part of the detection light is incident to the diffuse reflection layer after being reflected by the second reflection type polarizing film layer to be subjected to diffuse reflection, so that part of the light after being subjected to diffuse reflection is irradiated to the finger through the second reflection type polarizing film layer, and the light path guide structure is used for guiding the fingerprint detection light which is reflected by the finger, carries fingerprint information and penetrates through the liquid crystal display screen to the optical fingerprint sensor; the optical fingerprint sensor is used for acquiring fingerprint information of the finger according to the fingerprint detection light;

the second reflection type polarized light film layer is arranged above the detection light source, the detection light source is positioned between the diffuse reflection layer and the second reflection type polarized light film layer, and the polarization direction of the second reflection type polarized light film layer is the same as that of the first reflection type polarized light film layer.

In the specific implementation manner of this application, backlight unit is including the backplate subassembly that is used for fixed light guide plate, and the position that backplate subassembly and detection light source correspond is equipped with first logical unthreaded hole, and second reflective polarisation rete sets up on the backplate subassembly, and second reflective polarisation rete covers first logical unthreaded hole at least.

In a specific embodiment of the present application, a polarization layer is further provided, and at least one of the detection light and the fingerprint detection light penetrates through the polarization layer, the polarization layer is used for filtering out S waves in the detection light and/or the fingerprint detection light, and the polarization layer is located above the optical fingerprint identification device under the screen;

In the specific implementation of this application, the polarization layer is established on the backplate subassembly, and second reflection formula polarisation rete is located between polarization layer and the detection light source to make the probe light shine on the finger through second reflection formula polarisation rete, polarization layer and liquid crystal display.

In the specific implementation of this application, the one side that the backplate subassembly deviates from the light guide plate is equipped with the fixed recess of fourth, and polarizing layer and second reflective polarisation rete stack gradually in the fixed recess of fourth.

In a specific embodiment of the present application, the polarization layer is disposed on the back plate assembly, and the polarization layer is at least located above the light path guiding structure, so that the fingerprint detection light is incident into the light path guiding structure through the polarization layer;

In a specific embodiment of the present application, the second reflective polarizing film layer covers at least the first light passing hole.

also comprises a second reflective polarizing film layer and a diffuse reflection layer,

the second reflective polarizing film layer is arranged above the detection light source, and the detection light source is positioned between the diffuse reflection layer and the second reflective polarizing film layer.

The application provides optical fingerprint identification device and system, liquid crystal display under screen, optical fingerprint identification device is applicable to the liquid crystal display who has display module assembly and backlight unit under the screen, wherein, sets up first reflection type polarisation rete between display module assembly and the backlight unit, and optical fingerprint identification device includes under the screen: the detection light source, the light path guide structure and the optical fingerprint sensor are arranged below the backlight module; the detection light source is used for emitting detection light, the detection light irradiates a finger through the liquid crystal display screen, and the light path guide structure is used for guiding the fingerprint detection light which is reflected by the finger, carries fingerprint information and penetrates through the liquid crystal display screen to the optical fingerprint sensor; the optical fingerprint sensor is used for acquiring fingerprint information of the finger according to the fingerprint detection light; at least one of the detection light and the fingerprint detection light penetrates through the polarization layer, the polarization layer is used for filtering S waves in the detection light and/or the fingerprint detection light, and the polarization layer is positioned above the optical fingerprint identification device under the screen; the polarization direction of the polarization layer is the same as that of the first reflective polarization film layer. When light is incident on the first reflection type polarizing film layer, the generated reflected light is S wave basically, the generated transmitted light is P wave basically, the S wave can interfere with the imaging of the fingerprint image, the polarizing layer is arranged above the optical fingerprint identification device under the screen, and the polarization direction of the polarizing layer is the same as that of the first reflection type polarizing film layer, so that the S wave component reflected by the first reflection type polarizing film layer can be filtered in the detection light and/or the fingerprint detection light through the polarizing layer, the interference of the reflected light on the imaging of the fingerprint image can be avoided, and the fingerprint identification accuracy of the fingerprint identification device is improved.

Drawings

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

FIG. 1 is an exploded view of natural light;

FIG. 2 is an exploded front view of natural light;

FIG. 3 is a schematic diagram of a principle of operation of a reflective polarized brightness enhancement film according to an embodiment of the present disclosure;

fig. 4 is a schematic structural diagram of an off-screen optical fingerprint identification apparatus according to an embodiment of the present application;

fig. 5 is a schematic diagram illustrating an operation principle of a polarization layer in the optical fingerprint identification device under a screen for filtering reflected light according to an embodiment of the present application;

FIG. 6 is a schematic diagram of another structure of an optical fingerprint identification device under a screen according to an embodiment of the present application;

FIG. 7 is a schematic diagram of another structure of an optical fingerprint identification device under a screen according to an embodiment of the present application;

FIG. 8 is a schematic diagram of another structure of an optical fingerprint identification device under a screen according to an embodiment of the present application;

FIG. 9 is a schematic diagram of another structure of an optical fingerprint identification device under a screen according to an embodiment of the present application;

FIG. 10 is a schematic diagram illustrating an improvement in illumination efficiency in yet another configuration of an optical fingerprint identification device under a screen according to an embodiment of the present application;

fig. 11 is a schematic structural diagram of an off-screen optical fingerprint identification device according to a second embodiment of the present application;

fig. 12 is a schematic structural diagram of an off-screen optical fingerprint identification device according to a fourth embodiment of the present application;

fig. 13 is a schematic view of another structure of an off-screen optical fingerprint identification device according to the fourth embodiment of the present application.

Description of reference numerals:

1-a display module; 2-a backlight module; 3-a first reflective polarizing film layer; 5-a second reflective polarizing film layer; 6-optical path guiding structure; 7-an optical fingerprint sensor; 9-a polarizing layer; 11-a protective cover plate; 12-a liquid crystal display panel; 13-finger; 14-backlight light source; 15-middle frame; 16-an upper polarizer; 17-lower polarizer; 18-assembly clearance; 20-a diffusion sheet; 21-a light guide plate; 22-a backplane assembly; 23-a first clear aperture; 24-a second light aperture; 25-a brightness enhancement film; 26-a reflective film; 27-a back plate; 28-a backplane protective layer; 29-black tape; 31-the light transmission direction of the first reflective polarizing film layer; 32-polarization direction of the polarizing layer; 33-the light transmission direction of the second reflective polarizing film layer; 50-a detection light source; 51-a diffuse reflective layer; 71-a filter layer; 72-a stationary part; 80-a reflective polarized brightness enhancement film; 81-LED; 100-an underscreen optical fingerprint recognition device; 231 — a first fixing groove; 232-flexible circuit board FPC; 241-a second fixing groove; 242-third fixing groove; 243-fourth fixing groove; 281-groove.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The technical solution of the present application will be described in detail below with specific examples. The following several specific embodiments may be combined with each other, and details of the same or similar concepts or processes may not be repeated in some embodiments.

The liquid crystal display panel in the present application includes a first reflective polarizing Film layer, and the first reflective polarizing Film layer is a Dual Brightness Enhancement Film (DBEF). Optionally, the liquid crystal display panel further includes a second reflective polarizing film layer, which is also a reflective polarizing brightness enhancement film, and the light incident on the first reflective polarizing film layer or the second reflective polarizing film layer has about 50% reflection and 50% transmission.

Specifically, fig. 1 is an exploded schematic view of natural light, and fig. 2 is an exploded front schematic view of natural light. As shown in fig. 1 and 2, light has polarization characteristics, and can be divided into P-waves and S-waves according to the relationship between the polarization direction and the propagation direction (indicated by the symbol "B" in the figure), the polarization direction of the P-waves is parallel to the propagation plane of light, the polarization direction of the S-waves is perpendicular to the propagation plane of light, and natural light can be considered to be formed by mixing 50% of the P-waves and 50% of the S-waves.

Fig. 3 is a schematic diagram illustrating the operation principle of the reflective polarized brightness enhancement film according to the embodiment of the present disclosure, wherein the dotted arrow indicates the light passing direction. As shown in fig. 3, in the present application, an LED 81 is generally used as a detection light source, and the light emitted from the LED 81 is natural light, and assuming that the intensity thereof is a, the intensities of both the P-wave and the S-wave are a/2. The macroscopic characteristics of the reflective brightness enhancement film 80 are that when light emitted from the LED 81 is incident on the reflective brightness enhancement film 80, the reflected light is substantially S-wave as indicated by the downward arrow in fig. 3; the transmitted light is substantially P-wave, as indicated by the black arrows above the reflective polarizing brightness enhancement film 80. Thus, natural light from the LED 81 passes through the brightness enhancement film 80 with a reflection of about 50% (S wave component with intensity A/2) and a transmission of about 50% (P wave component with intensity A/2).

Due to the above characteristics of the reflective polarizing brightness enhancement film, when the liquid crystal display panel includes the first reflective polarizing film layer, about 50% of reflection and 50% of projection are generated when the liquid crystal display panel passes through the first reflective polarizing film layer, regardless of the detection light emitted from the light source or the fingerprint detection light formed on the finger. Therefore, the fingerprint identification module of the prior art has the following two problems:

in the first aspect, when the reflected light falls within the field of view of the lens group, interference may be caused to the imaging of the fingerprint image, and the fingerprint identification accuracy is not high.

In a second aspect, the intensity of the light that causes the reflected interference is 50%, and the proportion of transmitted light that participates in the imaging of the fingerprint image is relatively small, thereby making the illumination of the finger by the light source less efficient.

The present application is proposed to solve the above problems.

Example one

Fig. 4 is the optical fingerprint identification device's under screen schematic structure diagram that this application embodiment a provided, as shown in fig. 4, the optical fingerprint identification device under screen of this embodiment is applicable to the liquid crystal display who has display module assembly 1 and backlight unit 2, wherein, sets up first reflection formula polarisation rete 3 between display module assembly 1 and the backlight unit 2, and optical fingerprint identification device 100 includes under screen: the detection light source 50, the light path guide structure 6 and the optical fingerprint sensor 7 are arranged below the backlight module 2; the detection light source 50 is used for emitting detection light, the detection light irradiates the finger 13 through the liquid crystal display screen, and the light path guide structure 6 is used for guiding the fingerprint detection light which is reflected by the finger 13, carries fingerprint information and penetrates through the liquid crystal display screen to the optical fingerprint sensor 7; the optical fingerprint sensor 7 is used for acquiring fingerprint information of the finger 13 according to the fingerprint detection light; at least one of the detection light and the fingerprint detection light penetrates through the polarization layer 9, the polarization layer 9 is used for filtering S waves in the detection light and/or the fingerprint detection light, and the polarization layer 9 is positioned above the optical fingerprint identification device under the screen; the polarization direction of the polarizing layer 9 is the same as the polarization direction of the first reflective polarizing film layer 3. In the above scheme, when light is incident on the first reflective polarizing film layer 3, the generated reflected light is substantially S-wave, and the generated transmitted light is substantially P-wave, where the S-wave interferes with the imaging of the fingerprint image, and the polarization layer 9 is disposed above the optical fingerprint identification device under the screen, and the polarization direction of the polarization layer 9 is the same as the polarization direction of the first reflective polarizing film layer 3, so that the S-wave component that may be reflected by the first reflective polarizing film in the detection light and/or the fingerprint detection light can be filtered by the polarization layer 9, and the interference of the reflected light with the imaging of the fingerprint image can be avoided, thereby improving the fingerprint identification accuracy of the fingerprint identification device.

In the optical fingerprint identification device under the screen of this embodiment, be applicable to the liquid crystal display who has display module assembly 1 and backlight unit 2. The display module 1 includes a protective cover 11 and a liquid crystal display panel 12, wherein the liquid crystal display panel 12 may be a touch display panel with a touch detection function, and the protective cover 11 is disposed above the liquid crystal display panel 12 for protecting the liquid crystal display panel 12 and providing a human-computer interaction interface for a user to operate with fingers. The backlight module 2 is arranged below the display module 1 and used for providing a backlight source for the display module 1; the backlight module 2 includes a backlight source 14, and visible light emitted from the backlight source 14 is converted into a uniform surface light source by the backlight module 2 and illuminates the display module 1 to display a picture. It is understood that the protective cover 11 may be, for example, a glass cover or a sapphire cover, and thus, in the embodiment of the present application, the pressing of the so-called finger 13 on the liquid crystal display may specifically be pressing on the protective cover 11 or a protective layer (such as a tempered film or other protective film) covering the surface of the protective cover 11.

Specifically, the first reflective polarizing film layer 3 is the above-mentioned reflective polarizing brightness enhancement film, and has the following characteristics: for light incident on the first reflective polarizing film layer 3, approximately 50% reflection and 50% transmission occur.

In order to ensure that the detection light emitted by the detection light source 50 and the fingerprint detection light formed by the detection light source irradiating the finger 13 can pass through the backlight module 2, in the embodiment, at least a partial region of the backlight module 2 is a transparent region capable of transmitting the fingerprint detection light, the transparent region can be specifically a region corresponding to a transmission path of the detection light and the fingerprint detection light formed by the finger 13 on the liquid crystal display screen, and the transmission waveband covers an emission waveband of the detection light source 50, so that the detection light and the fingerprint detection light formed by the finger 13 can pass through the transparent region of the backlight module 2.

In the embodiment of the present application, the backlight module 2 includes the light guide plate 21 and the back plate assembly 22 for fixing the light guide plate 21, and the light-transmitting area may be formed by: the position that backplate subassembly 22 corresponds with detection light source 50 is equipped with first logical unthreaded hole 23, and the position that backplate subassembly 22 corresponds with light path guide structure 6 is equipped with second logical unthreaded hole 24, and first logical unthreaded hole 23 can make the detection light that detects light source 50 sent permeate through, and inject into light guide plate 21, and second logical unthreaded hole 24 can make the fingerprint detection light that permeates through light guide plate 21 permeate through, and enter into light path guide structure 6.

In addition, the optical fingerprint recognition device under the screen includes: the detection light source 50, the light path guide structure 6 and the optical fingerprint sensor 7 are arranged below the backlight module 2; wherein, detecting light source 50 can specifically set up in liquid crystal display's backlight unit 2's below, and detecting light source 50 can specifically be the light source that has different wave bands with backlight (visible light) that backlight unit 2 provided, and it can be used for the probe light of launching specific wave band, and the probe light of specific wave band is used for supplying to produce fingerprint detection light on the finger 13.

Specifically, the detection light source 50 may be configured to emit detection light to the finger 13 above the liquid crystal display, the detection light irradiates the finger 13 through the backlight module 2 and the display module 1, and forms fingerprint detection light carrying fingerprint information after being reflected or transmitted by the finger 13, and the light path guiding structure 6 is configured to guide the fingerprint detection light reflected by the finger 13, carrying the fingerprint information, and passing through the liquid crystal display to the optical fingerprint sensor 7; the optical fingerprint sensor 7 is used to acquire fingerprint information of the finger 13 from the fingerprint detection light.

In the embodiment of the present application, the detection light emitted by the detection light source 50 to the finger 13 and the visible light provided by the backlight module 2 are lights in different wavelength bands, for example, the detection light in a specific wavelength band may be invisible light, such as infrared light, outside the visible wavelength band. That is to say, the user can not see or perceive the above-mentioned detecting light for fingerprint identification through the display module 1, and the optical signal of the display image of the display module 1 is the visible light of the backlight module 2. Therefore, the interference of the detection light emitted by the detection light source 50 to the display effect of the display module 1 can be avoided.

In this embodiment, the detection light emitted by the detection light source 50 may be infrared light or other light signals with wavelengths outside the wavelength band of visible light and capable of realizing fingerprint identification.

In the embodiment of the present application, the optical fingerprint sensor 7 includes an optical sensing array having a plurality of sensing units, and a reading circuit and other auxiliary circuits electrically connected to the optical sensing array. The sensing area of the optical sensing array may correspond to a fingerprint recognition area of the optical fingerprint sensor 7. The optical fingerprint sensor 7 may be located below the fingerprint identification area of the liquid crystal display, or may be located in another area (for example, an edge area of the liquid crystal display); also, in the present embodiment, the optical path guiding structure 6 may be used to guide the fingerprint detection light of the fingerprint identification area to the optical fingerprint sensor 7, so that the optical sensing array may receive the fingerprint detection light to detect the fingerprint information of the finger 13 corresponding to the fingerprint detection light.

As an alternative implementation, the optical sensing array of the optical fingerprint sensor 7 and other circuits may be fabricated on a chip (Die) by a semiconductor process, where the optical sensing array is specifically a photo detector (photo detector) array, which includes a plurality of photo detectors distributed in an array, and the photo detectors may be used as the optical sensing units. On the other hand, as mentioned above, the off-screen optical fingerprint identification device may further include the optical path guiding structure 6 and other optical components, and the optical path guiding structure 6 and other optical components may be disposed below the fingerprint identification area of the liquid crystal display screen; wherein, the light path guiding structure 6 is mainly used for guiding the fingerprint detection light to the optical sensing array of the optical fingerprint sensor 7 for optical detection; the other optical components may include a Filter layer 71(Filter), and the Filter layer 71 may be disposed between the optical path guiding structure 6 and the optical fingerprint sensor 7 for filtering the interference light passing through the optical path guiding structure 6 to prevent the interference light from being received by the optical sensor array to affect the fingerprint identification performance.

In the optical fingerprint recognition device under the screen provided in this embodiment, the optical fingerprint sensor 7, the optical path guiding structure 6 and the filter layer 71 may be packaged in the same fixing component 72.

The optical path directing structure 6 may take a variety of implementations. As an example, the optical path directing structure 6 may be an optical Lens (Lens) layer having one or more Lens units, such as a Lens group consisting of one or more aspheric lenses. The optical lens layer may be used to condense the fingerprint detection light formed from the finger 13 and passing through the liquid crystal display screen to the optical sensing array of the optical fingerprint sensor 7 therebelow, so that the optical sensing array may perform optical imaging based on the fingerprint detection light, thereby obtaining a fingerprint image of the finger 13.

As another alternative embodiment, the optical path guiding structure 6 may be specifically a Collimator (Collimator) layer fabricated on a semiconductor silicon chip or other substrate, and has a plurality of collimating units, which may be specifically collimating through holes with a certain aspect ratio; when the user carries out fingerprint identification at liquid crystal display, in the fingerprint detection light that the finger 13 of liquid crystal display top formed and passed liquid crystal display, the fingerprint detection light that incident angle and this collimation unit's extending direction are unanimous basically can pass the collimation unit is received by the induction element of its below, and the fingerprint detection light that the incident angle degree is too big is attenuated through multiple reflection in this collimation unit inside, therefore every induction element can only receive the fingerprint detection light that the fingerprint line that its is directly over formed basically, thereby make the fingerprint detection light that the optical induction array utilized each detection element to detect respectively obtains the fingerprint image of finger 13.

In other embodiments, the optical path guiding structure 6 may further specifically include a Micro-Lens (Micro-Lens) layer and an optical film layer, the Micro-Lens layer includes a Micro-Lens array formed by a plurality of Micro-lenses, which may be formed above the optical sensing array of the optical fingerprint sensor through a semiconductor growth process or other processes, and each Micro-Lens may respectively correspond to one or more sensing units of the optical sensing array. An optical film layer may be formed between the microlens layer and the optical sensing unit, and may include at least one light blocking layer having micro-holes, and a dielectric layer, a passivation layer, or a buffer layer, etc., formed between the light blocking layer and the microlens layer and the optical sensing array, wherein the at least one light blocking layer having micro-holes adopts a specific optical design such that the micro-holes are formed between the corresponding microlenses and the sensing units, thereby defining a receiving optical path of the sensing units. The light blocking layer can block optical interference between adjacent micro lenses and the sensing unit, and the micro lenses converge received light rays into the micro holes at a specific vertical or inclined angle and transmit the light rays to the sensing unit through the micro holes for optical fingerprint imaging.

In the embodiment of the present application, the detection light source 50, the light path guiding structure 6 and the optical fingerprint sensor 7 are optionally disposed on the middle frame 15 of the liquid crystal display. Specifically, the middle frame 15 is fixed on the back surface of the back plate assembly 22 of the backlight module 2, the surface of the middle frame 15 facing the backlight module 2 is provided with a first fixing groove 231 and a second fixing groove 241, the detection light source 50 is fixed in the first fixing groove 231, the first fixing groove 231 is communicated with the first light through hole 23, and the notch of the first fixing groove 231 is arranged at a position corresponding to the first light through hole 23; the light path guide structure 6 and the optical fingerprint sensor 7 are fixed in the second fixing groove 241, and the second fixing groove 241 and the second light passing hole 24 are communicated, and the notch of the second fixing groove 241 is disposed at a position corresponding to the second light passing hole 24. Illustratively, as shown in fig. 4, the notch size and the arrangement position of the first fixing groove 231 are the same as those of the first light passing hole 23, and the notch size and the arrangement position of the second fixing groove 241 are the same as those of the second light passing hole 24.

In the application, in order to avoid the problem that reflected light of the first reflective polarizing film layer 3 falls within the field of view of the light path guide structure 6 and interferes with the imaging of a fingerprint image, at least one of the detection light and the fingerprint detection light can penetrate through the polarizing layer 9, the polarizing layer 9 is used for filtering S-waves in the detection light and/or the fingerprint detection light, and the polarizing layer 9 is located above the optical fingerprint identification device under the screen; the polarization direction of the polarizing layer 9 is the same as the polarization direction of the first reflective polarizing film layer 3.

Fig. 5 is a schematic diagram illustrating a working principle of a polarization layer in the optical fingerprint identification device under the screen for filtering reflected light according to an embodiment of the present application, and a filtering principle of the polarization layer 9 is described below by taking a case that S-waves are filtered after the detection light emitted by the detection light source 50 shown in fig. 5 passes through the polarization layer 9 as an example.

As shown in fig. 5, the polarization direction of the polarizing layer 9 is indicated by a reference numeral "32", the light transmission direction of the first reflective polarizing film layer 3 is indicated by a reference numeral "31", the polarization direction of the polarizing layer 9 is the same as the transmission polarization direction (light transmission direction) of the first reflective polarizing film layer 3, as shown in fig. 5, the probe light emitted from the detection light source 50 has an incident intensity a, after passing through the polarizing layer 9, the S wave having an intensity of substantially a/2 is absorbed by the polarizing layer 9, a minute amount of the S wave not absorbed and the P wave having an intensity of a/2 are transmitted through the polarizing layer 9, and when passing through the first reflective polarizing film layer 3, the P wave polarization direction is the same as the transmission polarization direction of the first reflective polarizing film layer 3, and therefore, the P wave having an intensity of a/2 is transmitted through the first reflective polarizing film layer 3 with almost no attenuation and is irradiated to the finger through the display module, meanwhile, the first reflective polarizing film layer 3 reflects a trace amount of S-waves, and the intensity of the reflected light is almost zero. In this way, after the detection light emitted by the detection light source 50 is filtered by the polarizing layer 9, almost no reflected light appears even if the first reflective polarizing film layer 3 is irradiated, which solves the problem that the reflected light interferes with the imaging mentioned at the beginning.

It can be understood that the principle of filtering the S wave in the fingerprint detection light by the polarization layer 9 is similar to that of filtering the S wave in the fingerprint detection light by the polarization layer 9, and the fingerprint detection light generated on the finger 13 is filtered by the polarization layer 9 after passing through the display module 1, and only the P wave is transmitted, so that even if there is interference reflected light and stray light, the interference reflected light and the stray light are filtered by the polarization layer 9, and the problem of interference of the reflected light with the imaging can be avoided.

Note that the above-mentioned polarization direction of the polarizing layer 9 is the same as the polarization direction of the first reflective polarizing film layer 3, specifically, the polarization direction of the polarizing layer 9 is substantially the same as the polarization direction of the first reflective polarizing film layer 3, and for example, if the difference between them is in the range of-5 ° to +5 °, the filtering effect of the polarizing layer 9 is considered to be within an allowable range.

In the embodiment of the present application, the polarization layer may be disposed at a light exit surface of the backlight module, or at a back surface of the backlight module away from the light exit surface, or in the backlight module. That is, the polarizing layer may be provided between the detection light source and the first reflective polarizing film layer.

Fig. 6 is a schematic view of another structure of an off-screen optical fingerprint identification device according to an embodiment of the present disclosure, and as shown in fig. 6, a display module includes a protective cover plate 11, an upper polarizer 16, a liquid crystal display panel 12, a lower polarizer 17, and a first reflective polarizing film layer 3, which are sequentially stacked; the backlight module includes a diffusion sheet 20, a brightness enhancement film 25, a light guide plate 21, a reflection film 26, a back plate 27, and a back plate protective layer 28, which are sequentially stacked. A fitting gap 18 is provided between the first reflective polarizing film layer 3 and the diffusion sheet 20, a black tape 29 is further provided on the side of the diffusion sheet 20 and the brightness enhancement film 25 to block light, and a backlight source 14 is further provided on the side of the light guide plate 21. Specifically, the polarizing layer 9 may be disposed on the light exit surface of the backlight module 2, i.e. the diffusion sheet 20, or may be disposed on the back surface of the backlight module 2 away from the light exit surface as shown in fig. 6. Or may be provided between any two adjacent ones of the diffusion sheet 20, the brightness enhancement film 25, the light guide plate 21, the reflection film 26, the back plate 27, and the back plate protective layer 28.

Further, as shown in fig. 4, a polarizing layer 9 may be disposed on the back sheet assembly 22. At this time, the polarizing layer 9 may be disposed in the groove 281 by disposing the groove 281 on the back sheet protective layer 28. Alternatively, the polarizing layer 9 may be disposed between the back plate 27 and the reflective film 26, or the polarizing layer 9 may be disposed between the back plate 27 and the back plate protective layer 28.

Further, as for the arrangement range of the polarizing layer 9, the polarizing layer 9 may be located at least above the detection light source 50, so that the probe light is irradiated to the finger 13 through the polarizing layer 9 and the liquid crystal display screen; in the case that the first light passing hole 23 is formed at a position of the back plate assembly 22 corresponding to the detection light source 50, the polarizing layer 9 above the detection light source 50 covers at least the first light passing hole 23.

Fig. 7 is a schematic view of another structure of an optical fingerprint identification device under a screen according to an embodiment of the present application, as shown in fig. 7, as an alternative implementation manner, a polarizing layer 9 is at least located above the optical path guiding structure 6, so that the fingerprint detection light is transmitted through the polarizing layer 9 and enters the optical path guiding structure 6, when a second light through hole 24 is provided at a position of the back plate assembly 22 corresponding to the optical path guiding structure 6, it is required that the polarizing layer 9 at least covers the second light through hole 24. In this case, even if the detection light and/or the fingerprint detection light irradiated to the first reflective polarizing film layer 3 is reflected, the reflected light is filtered after passing through the polarizing layer 9, and thus the reflected light does not affect the image formation of the optical fingerprint sensor 7.

Fig. 8 is a schematic diagram of another structure of an optical fingerprint identification device under a screen according to an embodiment of the present application, as shown in fig. 8, as an alternative implementation manner, a polarization layer 9 is simultaneously located above a detection light source 50 and above an optical path guiding structure 6, and the polarization layer 9 simultaneously covers a first light passing hole 23 and a second light passing hole 24, so that a detection light passes through the polarization layer 9, and irradiates a finger 13 after being filtered by an S wave; and the formed fingerprint detection light penetrates through the polarization layer 9, and is incident into the light path guide structure 6 after S wave is filtered, so that the filtering effect on the reflected light is optimal.

In the case where the polarizing layer 9 covers the second light passage aperture 24, the polarizing layer 9 above the light path guiding structure 6 covers at least the field of view of the optical lens layer, in case the light path guiding structure 6 comprises an optical lens layer comprising one or more aspheric lenses and being adapted to focus the fingerprint detection light onto the optical fingerprint sensor 7. In order to filter as much as possible all reflected light that may be incident on the optical path directing structure 6.

In the embodiment of the present application, fig. 9 is a schematic view of another structure of the off-screen optical fingerprint identification device provided in the first embodiment of the present application, and fig. 10 is a schematic view of a principle of improving illumination efficiency in another structure of the off-screen optical fingerprint identification device provided in the first embodiment of the present application, as shown in fig. 9 and 10, in order to solve the problem that the intensity of light generating reflection interference is 50%, the proportion of transmitted light participating in fingerprint image imaging is relatively small, and thus the illumination efficiency of a light source on a finger is low. Under the condition of not increasing the power and the number of the detection light sources 50, a second reflection type polarizing film layer 5 and a diffuse reflection layer 51 can be further arranged, wherein the second reflection type polarizing film layer 5 is arranged between the detection light sources 50 and the polarizing layer 9 above the detection light sources 50; the detection light source 50 is located between the diffuse reflection layer 51 and the second reflective polarizing film layer 5.

As shown in fig. 10, the detection light source 50 emits detection light of intensity a, which passes through the second reflective polarizing film layer 5, and P-wave of intensity a/2 is transmitted therethrough, and S-wave of intensity a/2 is reflected and irradiated onto the diffuse reflection layer 51. The light passing direction of the second reflective polarizing film layer is shown by reference numeral 33.

When the diffuse reflection film 51 is irradiated with the S wave having an intensity of a/2, the S wave is diffusely reflected to form a divergent light, the direction of the S wave polarized light is disturbed to be restored to a natural light, the restored natural light passes through the second reflective polarizing film layer 5, the P wave is transmitted, and the S wave is reflected to be irradiated to the diffuse reflection film 51.

The above process is repeated, and finally, most of the natural light emitted from the detection light source 50 can be converted into P-wave polarized light, and the conversion rate can usually reach 80%, that is, the P-wave intensity finally transmitted through the second reflective polarizing film layer 5 is 0.8A.

This can solve the problem of the detection light source 50 that the illumination efficiency of the finger 13 is low.

The P wave with the intensity of 0.8A transmitted through the second reflective polarizing film layer 5 passes through the polarizing layer 9, and then a small amount of unabsorbed S wave and the P wave with the intensity of 0.8A pass through the polarizing layer 9, and when passing through the first reflective polarizing film layer 3, the P wave polarization direction is the same as the transmission polarization direction of the first reflective polarizing film layer 3, so that the P wave with the intensity of 0.8A passes through the first reflective polarizing film layer 3 almost without attenuation and passes through the display module to irradiate the finger, and at the same time, the first reflective polarizing film layer 3 reflects a small amount of S wave, and the reflected light intensity is almost zero. Thus, the detection light emitted by the detection light source 50 is reinforced by the second reflective polarizing film layer 5 and the diffuse reflection film 51, and after being filtered by the polarizing layer 9, the reflected light cannot appear even if the detection light irradiates the first reflective polarizing film layer 3, so that the problem of interference of the reflected light with imaging is solved.

As shown in fig. 9, the second reflective polarizing film layer 5 is disposed on the backplane assembly, and the second reflective polarizing film layer 5 at least covers the first light passing hole 23. Since the light emitted from the detection light source 50 is incident into the light guide plate through the first light passing hole 23, when the second reflective polarizing film layer 5 covers the first light passing hole 23, the detection light emitted from the detection light source 50 can be converted as much as possible. It is understood that the diffuse reflection layer 51 is provided in a range corresponding to the second reflective polarizing film layer 5, and the diffuse reflection layer 51 covers the second reflective polarizing film layer 5 in a plan view.

In the embodiment of the present application, a flexible printed circuit board FPC 232 is further disposed on the middle frame 15, the detection light source 50 is disposed on the flexible printed circuit board FPC 232, and the diffuse reflection layer 51 is disposed on a side of the flexible printed circuit board FPC 232 facing the detection light source 50. For example, after the detection light source 50 is disposed on the flexible printed circuit board FPC 232, the diffuse reflection layer 51 is disposed on a side of the flexible printed circuit board FPC 232 facing the display module 1, or the diffuse reflection layer 51 is disposed on a side of the flexible printed circuit board FPC 232 facing the display module 1, and then the detection light source 50 is disposed on the diffuse reflection layer 51, or the diffuse reflection layer 51 may be disposed on a side wall of the first fixing groove 231 to enhance the diffuse reflection effect on the detection light.

In the embodiment of the present application, the diffuse reflection layer 51 is a white ink layer or a silver powder layer.

In this embodiment, when light incides on the first reflection-type polarizing film layer, the reverberation of production is the S ripples basically, the transmitted light of production is the P ripples basically, this S ripples can cause the interference in the formation of image of fingerprint image, and through set up the polarization layer in the top of optical fingerprint identification device under the screen, and the polarization direction of polarization layer is the same with the polarization direction of first reflection-type polarizing film layer, consequently can will survey light and/or fingerprint detection light through the polarization layer, probably can be filtered by the S ripples component of first reflection-type polarizing film reflection, can avoid the reverberation to cause the interference to the formation of image of fingerprint image, thereby improve fingerprint identification device' S fingerprint identification accuracy.

Example two

The present embodiment provides an optical fingerprint identification system under screen that can be suitable for a liquid crystal display device on the basis of the first embodiment, fig. 11 is a schematic structural diagram of an optical fingerprint identification device under screen that the second embodiment of the present application provides, as shown in fig. 11, the optical fingerprint identification system under screen of the present embodiment includes a liquid crystal display screen 200 and an optical fingerprint identification device 100 under screen that is described in the first embodiment, the optical fingerprint identification device under screen is disposed below the liquid crystal display screen and is used for detecting fingerprint information of a finger 13 above the liquid crystal display screen. The optical fingerprint identification system under the screen can be applied to smart phones, tablet computers and other mobile terminals or electronic equipment adopting liquid crystal display screens.

In this embodiment, liquid crystal display includes display module 1 and backlight unit 2 and is located the first reflection-type polarisation rete 3 between display module 1 and the backlight unit 2, and backlight unit 2 sets up in display module 1 below for display module 1 provides the backlight, and the fingerprint detection light that the finger 13 above liquid crystal display formed sees through backlight unit 2 and transmits to the optical fingerprint identification device under the screen of backlight unit 2 below. The first reflective polarizing film layer 3 is a reflective polarizing brightness enhancement film having the following characteristics: for light incident on the first reflective polarizing film layer 3, approximately 50% reflection and 50% transmission occur.

The liquid crystal display further includes: the polarization layer 9 is arranged above the optical fingerprint identification device under the screen, at least one of the detection light and the fingerprint detection light penetrates through the polarization layer 9, and the polarization layer 9 is used for filtering S waves in the detection light and/or the fingerprint detection light; the polarization direction of the polarizing layer 9 is the same as the polarization direction of the first reflective polarizing film layer 3.

In this embodiment, the optical fingerprint recognition device under the screen includes: the detection light source 50, the light path guide structure 6 and the optical fingerprint sensor 7 are arranged below the backlight module 2; the detection light source 50 is used for emitting detection light, the detection light irradiates the finger 13 through the liquid crystal display screen, and the light path guide structure 6 is used for guiding the fingerprint detection light which is reflected by the finger 13, carries fingerprint information and penetrates through the liquid crystal display screen to the optical fingerprint sensor 7; the optical fingerprint sensor 7 is used to acquire fingerprint information of the finger 13 from the fingerprint detection light.

In this embodiment, the structures, the setting positions, the working principles, and the like of the display module 1, the backlight module 2, the polarization layer 9, and the optical fingerprint identification device under the screen have been described in detail in the first embodiment, and are not described herein again.

In this embodiment, when light incides on the first reflection-type polarizing film layer, the reverberation of production is the S ripples basically, the transmitted light of production is the P ripples basically, this S ripples can cause the interference in the formation of image of fingerprint image, and through set up the polarization layer in the top of optical fingerprint identification device under the screen, and the polarization direction of polarization layer is the same with the polarization direction of first reflection-type polarizing film layer, consequently can will survey light and/or fingerprint detection light through the polarization layer, probably can be by the S ripples component filtering that first reflection-type polarizing film reflects, can avoid the reverberation to cause the interference to the formation of image of fingerprint image, thereby improve optical fingerprint identification system' S under the screen fingerprint identification accuracy.

EXAMPLE III

The present embodiment provides a liquid crystal display supporting the function of fingerprint identification under a screen, and the optical fingerprint identification apparatus 100 under a screen described in the first embodiment is disposed below the liquid crystal display. The liquid crystal display panel includes: the display module comprises a display module 1, a backlight module 2 and a first reflective polarizing film layer 3 positioned between the display module 1 and the backlight module 2; backlight unit 2 sets up in display module 1 below for display module 1 provides the backlight, and make the fingerprint detection light that the finger 13 in the liquid crystal display top formed shine backlight unit 2 below and optics fingerprint identification device 100 under the screen of backlight unit 2, promptly in this embodiment, the fingerprint detection light can see through backlight unit 2 and transmit light path guide structure 6 and optics fingerprint sensor 7 to optics fingerprint identification device 100 under the screen. The first reflective polarizing film layer 3 is a reflective polarizing brightness enhancement film having the following characteristics: for light incident on the first reflective polarizing film layer 3, approximately 50% reflection and 50% transmission occur.

The liquid crystal display further includes: the polarization layer 9, the polarization layer 9 is arranged above the optical fingerprint identification device 100 under the screen, at least one of the detection light and the fingerprint detection light penetrates through the polarization layer 9, and the polarization layer 9 is used for filtering out S-waves in the detection light and/or the fingerprint detection light; the polarization direction of the polarizing layer 9 is the same as the polarization direction of the first reflective polarizing film layer 3.

In the liquid crystal display supporting the under-screen fingerprint identification function provided by this embodiment, when light is incident on the first reflective polarizing film layer, the generated reflected light is substantially a wave, and the generated transmitted light is substantially a P wave, where the S wave may interfere with imaging of a fingerprint image, and the polarizing layer is disposed above the under-screen optical fingerprint identification device, and the polarization direction of the polarizing layer is the same as the polarization direction of the first reflective polarizing film layer, so that S wave components reflected by the first reflective polarizing film may be filtered out from the detected light and/or fingerprint detection light through the polarizing layer.

Example four

In this embodiment, whether the polarization layer 9 is arranged or not is improved on the basis of the first embodiment, and the rest of the embodiments are the same as the first embodiment, wherein the structures, the arrangement positions, the working principles, and the like of the display module 1, the backlight module 2, the polarization layer 9, and the optical fingerprint identification device under the screen are described in detail in the first embodiment, and are not described herein again.

Fig. 12 is a schematic structural diagram of the optical fingerprint identification device under screen according to the fourth embodiment of the present application, and as shown in fig. 12, the optical fingerprint identification device under screen according to the present embodiment is suitable for a liquid crystal display screen having a display module 1 and a backlight module 2, wherein a first reflective polarizing film layer 3 is disposed between the display module 1 and the backlight module 2. Optical fingerprint identification device includes under the screen: the detection light source 50, the light path guide structure 6 and the optical fingerprint sensor 7 are arranged below the backlight module 2; the detection light source 50 is used for emitting detection light, part of the detection light is reflected by the second reflective polarizing film layer 5 and then enters the diffuse reflection layer 51 for diffuse reflection, so that part of the light after diffuse reflection passes through the second reflective polarizing film layer 5 and irradiates on the finger 13, and the light path guide structure 6 is used for guiding the fingerprint detection light which is reflected by the finger 13, carries fingerprint information and passes through the liquid crystal display screen to the optical fingerprint sensor 7; the optical fingerprint sensor 7 is used for acquiring fingerprint information of the finger 13 according to the fingerprint detection light; the second reflective polarizing film layer 5 is arranged above the detection light source 50, and the detection light source 50 is positioned between the diffuse reflection layer 51 and the second reflective polarizing film layer 5; the polarization direction of the second reflective polarizing film layer 5 is the same as the polarization direction of the first reflective polarizing film layer 3.

In the above-described embodiment, when light is incident on the first reflective polarizing film layer 3, the generated reflected light is substantially an S wave and the generated transmitted light is substantially a P wave, the S wave interfering with the image formation of a fingerprint image, and when the detection light source 50 is positioned between the diffuse reflection layer 51 and the second reflective polarizing film layer 5 and the polarization direction of the second reflective polarizing film layer 5 is the same as the polarization direction of the first reflective polarizing film layer 3, approximately 50% of the P wave is transmitted and the remaining 50% of the S wave is reflected and irradiated on the diffuse reflection layer 51, the S wave irradiated on the diffuse reflection film 51 is diffusely reflected to form divergent light, the polarization direction of the S wave is disturbed and reduced to natural light, and the reduced natural light is transmitted and passed through the second reflective polarizing film layer 5, the S wave is reflected to impinge on the diffusive reflective layer 51. The above process is repeated continuously, and finally, natural light emitted by most of the detection light sources 50 can be converted into P-wave polarized light, generally, 80% of conversion rate can be achieved, and the intensity of the finally generated reflected S-wave is about 20%, which greatly reduces the amount of reflected light compared with the situation of generating 50% of reflected S-wave in the prior art, thereby reducing the degree of imaging interference of the reflected light on the fingerprint image, and improving the fingerprint identification accuracy of the optical fingerprint identification device 100 under the screen. The specific conversion process can refer to the first embodiment and the process discussed in fig. 10, and will not be described in detail here.

On the other hand, the P-wave intensity finally transmitted through the second reflective polarizing film layer 5 is 80%, which improves the utilization rate of the probe light and makes the illumination efficiency of the detection light source 50 to the finger 13 higher without increasing the power and number of the detection light sources 50 compared with the prior art that only 50% of the P-wave is transmitted.

Specifically, among the optical fingerprint identification device under the screen of this embodiment, be applicable to the liquid crystal display who has display module assembly 1 and backlight unit 2. The display module 1 includes a protective cover 11 and a liquid crystal display panel 12, wherein the liquid crystal display panel 12 may be a touch display panel with a touch detection function, and the protective cover 11 is disposed above the liquid crystal display panel 12 for protecting the liquid crystal panel and providing a human-computer interaction interface operated by a finger 13 for a user. The backlight module 2 is arranged below the display module 1 and used for providing a backlight source for the display module 1; the backlight module 2 comprises a backlight source, and visible light emitted by the backlight source is converted into a uniform surface light source through the backlight module 2 and irradiates the display module 1 to display pictures. It is understood that the protective cover 11 may be, for example, a glass cover or a sapphire cover, and thus, in the embodiment of the present application, the pressing of the so-called finger 13 on the liquid crystal display may specifically be pressing on the protective cover 11 or a protective layer (such as a tempered film or other protective film) covering the surface of the protective cover 11. The polarization direction of the second reflective polarizing film layer 5 is the same as the polarization direction of the first reflective polarizing film layer 3, specifically, substantially the same, and for example, the difference between them is considered to be within an allowable range from-5 ° to +5 °.

The detection light source 50, the light path guiding structure 6, the optical fingerprint sensor 7, and the like disposed below the backlight module 2 included in the underscreen optical fingerprint identification device are described in detail in the first embodiment, and are not described herein again.

The optical fingerprint identification device further includes a second reflective polarizing film layer 5 and a diffuse reflection layer 51, the second reflective polarizing film layer 5 is also a reflective polarizing brightness enhancement film, and the second reflective polarizing film layer 5 also has the following characteristics: for light incident on the second reflective polarizing film layer 5, approximately 50% reflection and 50% transmission occur.

In addition, the diffuse reflection is a phenomenon in which light projected on a rough surface is reflected in various directions. When a parallel incident light beam strikes a rough surface, the surface reflects the light beam in all directions, so that although the incident light beams are parallel to each other, the reflected light beams are randomly reflected in different directions due to the non-uniform normal directions of the points, and the reflection is called as "diffuse reflection". The diffuse reflection film 51 in this embodiment may randomly reflect the S-wave reflected by the second reflective polarizing film layer 5 in different directions, and finally return to the natural light to irradiate the second reflective polarizing film layer 5 again.

The second reflective polarizing film layer 5 is disposed above the detection light source 50, which means that the second reflective polarizing film is disposed on a light exiting surface side of the detection light source 50, so that the detection light emitted by the detection light source 50 can irradiate on the second reflective polarizing film. When the detection light source 50 is located between the diffuse reflection layer 51 and the second reflective polarizing film layer 5, the second reflective polarizing film layer 5 may reflect the S-wave component in the probe light emitted from the detection light source 50 onto the diffuse reflection layer 51. In order to allow the P-wave transmitted through the second reflective polarizing film layer 5 to smoothly transmit through the first reflective polarizing film layer 3, the polarization direction of the second reflective polarizing film layer 5 and the polarization direction of the first reflective polarizing film layer 3 need to be the same.

As shown in fig. 12, the first light passing hole 23 on the back plate assembly 22 corresponds to the first fixing groove on the middle frame 15, and the second reflective polarizing film layer 5 is required to cover at least the first light passing hole 23, for example, a third fixing groove 242 may be provided at the aperture of the first light passing hole 23 facing the detection light source 50, and the second reflective polarizing film layer 5 may be provided in the third fixing groove 242 on the back plate assembly 22, so that the second reflective polarizing film layer 5 covers the light outgoing range of the detection light source 50.

In addition, in order to further reduce the reflected wave, a polarization layer may be further disposed above the under-screen optical fingerprint identification device, fig. 13 is a schematic diagram of another structure of the under-screen optical fingerprint identification device provided in the fourth embodiment of the present application, as shown in fig. 13, at least one of the detection light and the fingerprint detection light transmits through the polarization layer 9, the polarization layer 9 is configured to filter out S-waves in the detection light and/or the fingerprint detection light, and a polarization direction of the polarization layer 9 is the same as a polarization direction of the first reflective polarization film layer 3.

Optionally, the polarization layer 9 is disposed on a light-emitting surface of the backlight module, or on a back surface of the backlight module away from the light-emitting surface, or in the backlight module.

Further, the polarizing layer 9 is disposed on the back plate assembly 22, and the second reflective polarizing film layer 5 is disposed between the polarizing layer 9 and the detection light source 50, so that the detection light is irradiated to the finger 13 through the second reflective polarizing film layer 5, the polarizing layer 9 and the liquid crystal display. As shown in fig. 13, the arrangement enables the detection light converted by the second reflective polarizing film layer 5 and the diffuse reflection layer 51 to pass through the polarizing layer 9, and the polarizing layer 9 further filters a small amount of S-waves in the detection light, so as to avoid interference of the reflected light on fingerprint imaging.

In addition, a fourth fixing groove 243 is further disposed at a position on the back plate protection layer 28 corresponding to the first light through hole 23 and the second light through hole 24, the fourth fixing groove 243 is disposed on a surface of the back plate protection layer 28 facing away from the light guide plate 21, the polarizing layer 9 may be disposed in the fourth fixing groove 243, and then the second reflective polarizing film layer 5 is also disposed in the fourth fixing groove 243 and is overlapped on the polarizing layer 9. When the middle frame 15 is attached to the back-plate protection layer 28, the upper surface of the middle frame 15 may abut against the lower surface of the second reflective polarizing film layer 5 to position the second reflective polarizing film layer.

The arrangement position, the arrangement range, and the like of the polarizing layer 9 have already been described in detail in one embodiment, and are not described again here. It is understood that, in the case where the second reflective polarizing film layer 5 and the diffuse reflection layer 51 are provided, the present embodiment may further include various modifications of the polarizing layer 9 described in the first embodiment.

In the embodiment of the application, the detection light source is located between the diffuse reflection layer and the second reflection type polarization film layer, and the polarization direction of the second reflection type polarization film layer is the same as that of the first reflection type polarization film layer 3, when the detection light source irradiates on the second reflection type polarization film layer, about 50% of P waves are transmitted and pass, the rest 50% of S waves are reflected and irradiate on the diffuse reflection layer, 50% of S waves irradiate on the diffuse reflection film and are subjected to diffuse reflection to form divergent light, the direction of the S wave polarized light is disordered and is reduced into natural light, the reduced natural light passes through the second reflection type polarization film layer, the P waves are transmitted and pass, and the S waves are reflected and irradiate on the diffuse reflection layer. The above process is repeated continuously, and finally natural light emitted by most of detection light sources can be converted into P wave polarized light, and the conversion rate of 80% can be achieved generally, namely, the intensity of S wave finally generated by reflection is about 20%, compared with the situation of generating 50% of reflected S wave in the prior art, the quantity of reflected light is greatly reduced, and therefore the imaging interference degree of the reflected light on fingerprint images is reduced, and the fingerprint identification accuracy of the optical fingerprint identification device under the screen is improved.

EXAMPLE five

The present embodiment provides an optical fingerprint identification system under screen that can be suitable for a liquid crystal display device on the basis of the fourth embodiment, and the optical fingerprint identification system under screen of the present embodiment includes a liquid crystal display screen and the optical fingerprint identification device 100 under screen of the second embodiment, the optical fingerprint identification device 100 under screen is disposed below the liquid crystal display screen and is used for detecting fingerprint information of the finger 13 above the liquid crystal display screen. The optical fingerprint identification system under the screen can be applied to smart phones, tablet computers and other mobile terminals or electronic equipment adopting liquid crystal display screens.

In this embodiment, the liquid crystal display includes a display module 1, a backlight module 2, and a first reflective polarizing film layer 3 located between the display module 1 and the backlight module 2, where the backlight module 2 is disposed below the display module 1 and is used to provide a backlight source for the display module 1; the first reflection type polarized light film layer 3 is a reflection type polarized light brightness enhancement film, which has the following characteristics: for light incident on the first reflective polarizing film layer 3, approximately 50% reflection and 50% transmission occur.

The liquid crystal display panel further includes: a second reflective polarizing film layer 5 and a diffuse reflection layer 51, wherein the second reflective polarizing film layer 5 is arranged above the detection light source 50, and the detection light source 50 is positioned between the diffuse reflection layer 51 and the second reflective polarizing film layer 5; the polarization direction of the second reflective polarizing film layer 5 is the same as the polarization direction of the first reflective polarizing film layer 3.

In this embodiment, the optical fingerprint recognition device 100 includes: the detection light source 50, the light path guide structure 6 and the optical fingerprint sensor 7 are arranged below the backlight module 2; the detection light source 50 is used for emitting detection light, the detection light irradiates the finger 13 through the liquid crystal display screen, and the light path guide structure 6 is used for guiding the fingerprint detection light which is reflected by the finger 13, carries fingerprint information and penetrates through the liquid crystal display screen to the optical fingerprint sensor 7; the optical fingerprint sensor 7 is used to acquire fingerprint information of the finger 13 from the fingerprint detection light.

In this embodiment, the structures, the setting positions, the working principles, and the like of the display module 1, the backlight module 2, the polarization layer 9, and the optical fingerprint identification device 100 under the screen have been described in detail in the first embodiment and the fourth embodiment, and are not described herein again.

In the embodiment of the application, the detection light source is located between the diffuse reflection layer and the second reflection type polarization film layer, the polarization direction of the second reflection type polarization film layer is the same as that of the first reflection type polarization film layer, when the detection light source irradiates on the second reflection type polarization film layer, about 50% of P waves are transmitted and pass, the rest 50% of S waves are reflected and irradiate on the diffuse reflection layer, 50% of S waves irradiate on the diffuse reflection film and are subjected to diffuse reflection to form divergent light, the direction of the S wave polarized light is disordered and is reduced into natural light, the reduced natural light passes through the second reflection type polarization film layer, the P waves are transmitted and pass, and the S waves are reflected and irradiate on the diffuse reflection layer. The above process is repeated continuously, and finally natural light emitted by most of detection light sources can be converted into P wave polarized light, and the conversion rate of 80% can be achieved generally, namely, the intensity of S wave finally generated by reflection is about 20%, compared with the situation of generating 50% of reflected S wave in the prior art, the quantity of reflected light is greatly reduced, and therefore the imaging interference degree of the reflected light on fingerprint images is reduced, and the fingerprint identification accuracy of the optical fingerprint identification device under the screen is improved.

EXAMPLE six

The present embodiment provides a liquid crystal display supporting the function of fingerprint identification under a screen, and the optical fingerprint identification apparatus 100 under a screen described in the fourth embodiment is disposed below the liquid crystal display. The liquid crystal display panel includes: the display module comprises a display module 1, a backlight module 2 and a first reflective polarizing film layer 3 positioned between the display module 1 and the backlight module 2; backlight unit 2 sets up in display module 1 below for display module 1 provides the backlight, and make the fingerprint detection light that the finger 13 in the liquid crystal display top formed transmit optical fingerprint identification device 100 under the screen of backlight unit 2 below, in this embodiment promptly, backlight unit 2 can make the light path guide structure 6 and the optical fingerprint sensor 7 that fingerprint detection light transmitted optical fingerprint identification device 100 under the screen. The first reflection type polarized light film layer 3 is a reflection type polarized light brightness enhancement film, which has the following characteristics: for light incident on the first reflective polarizing film layer 3, approximately 50% reflection and 50% transmission occur.

The liquid crystal display further includes: a second reflective polarizing film layer 5 and a diffuse reflection layer 51, wherein the second reflective polarizing film layer 5 is arranged above the detection light source 50, and the detection light source 50 is positioned between the diffuse reflection layer 51 and the second reflective polarizing film layer 5; the polarization direction of the second reflective polarizing film layer 5 is the same as the polarization direction of the first reflective polarizing film layer 3.

In this embodiment, the structures, the setting positions, the working principles, and the like of the display module, the backlight module, the polarization layer, and the optical fingerprint identification device under the screen have been described in detail in the first embodiment, and are not described herein again.

In the liquid crystal display supporting the underscreen fingerprint identification function provided in this embodiment, by positioning the detection light source between the diffuse reflection layer and the second reflection-type polarizing film layer, and making the polarization direction of the second reflection-type polarizing film layer the same as the polarization direction of the first reflection-type polarizing film layer, when the detection light source irradiates on the second reflection-type polarizing film layer, about 50% of the P wave is transmitted through, and the remaining 50% of the S wave is continuously converted through the second reflection-type polarizing film layer and the diffuse reflection film, so that most of the natural light emitted by the detection light source can be finally converted into P wave polarized light, which can generally reach 80% of conversion rate, that is, the intensity of the finally generated reflected S wave is about 20%, which greatly reduces the amount of reflected light compared with the case of generating 50% of reflected S wave in the prior art, and therefore, reduces the degree of interference of the reflected light with the imaging of the fingerprint image, therefore, the fingerprint identification accuracy of the optical fingerprint identification device under the screen is improved.

Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An optical fingerprint identification device under screen is suitable for a liquid crystal display screen with a display module and a backlight module, wherein a first reflective polarizing film layer is arranged between the display module and the backlight module,

the optical fingerprint recognition device under screen includes: the detection light source, the light path guide structure and the optical fingerprint sensor are arranged below the backlight module; the detection light source is used for emitting detection light, the detection light irradiates a finger through the liquid crystal display screen, and the light path guide structure is used for guiding fingerprint detection light which is reflected by the finger, carries fingerprint information and penetrates through the liquid crystal display screen to the optical fingerprint sensor; the optical fingerprint sensor is used for acquiring fingerprint information of the finger according to the fingerprint detection light; at least one of the detection light and the fingerprint detection light penetrates through a polarization layer, the polarization layer is used for filtering S waves in the detection light and/or the fingerprint detection light, and the polarization layer is located above the optical fingerprint identification device under the screen;

the polarization direction of the polarization layer is the same as the polarization direction of the first reflective polarizing film layer.

2. The device for optical fingerprint identification under screen of claim 1, wherein the polarization layer is disposed on the light exit surface of the backlight module, or on the back surface of the backlight module away from the light exit surface, or inside the backlight module.

3. The device of claim 2, wherein the backlight module comprises a back plate assembly for fixing the light guide plate, and the polarization layer is disposed on the back plate assembly.

4. The device of claim 3, wherein the polarizing layer is at least above the detection light source, such that the probe light is transmitted through the polarizing layer and the liquid crystal display to the finger;

5. The underscreen optical fingerprint recognition device of claim 3 or claim 4, wherein the polarizing layer is at least located above the optical path directing structure such that the fingerprint detection light is incident into the optical path directing structure through the polarizing layer;

and the position of the back plate component corresponding to the light path guide structure is provided with a second light through hole, and the polarization layer at least covers the second light through hole.

6. The underscreen optical fingerprint recognition device of claim 5, wherein the optical path directing structure comprises an optical lens layer comprising one or more aspheric lenses configured to focus the fingerprint detection light onto the optical fingerprint sensor, and a polarizing layer above the optical path directing structure covers at least a field of view of the optical lens layer.

7. The underscreen optical fingerprint identification device according to claim 4, wherein a second reflective polarizing film layer and a diffuse reflection layer are further provided,

the second reflective polarizing film layer is disposed between the detection light source and the polarizing layer above the detection light source; the detection light source is positioned between the diffuse reflection layer and the second reflective polarizing film layer;

the polarization direction of the second reflection type polarized light film layer is the same as that of the first reflection type polarized light film layer.

8. The off-screen optical fingerprint identification device of claim 7, wherein the second reflective polarizing film layer is disposed on the backplane assembly and covers at least the first clear aperture.

9. The device according to claim 7, further comprising a Flexible Printed Circuit (FPC), wherein the detection light source is disposed on the FPC, and the diffuse reflection layer is disposed on a side of the FPC facing the detection light source.

10. The underscreen optical fingerprint recognition device of claim 7 wherein the diffuse reflective layer is a white ink layer or a silver powder layer.

11. The device of any one of claims 1-4, wherein the detection light source, the light path guiding structure, and the optical fingerprint sensor are disposed on a center frame of the liquid crystal display.

12. An off-screen optical fingerprint identification system, characterized in that, comprises a liquid crystal display screen and the off-screen optical fingerprint identification device of any one of claims 1 to 11, wherein the off-screen optical fingerprint identification device is arranged below the liquid crystal display screen and is used for detecting fingerprint information of a finger above the liquid crystal display screen.

13. The system according to claim 12, wherein the polarization layer of the lcd is disposed on a light-emitting surface of the backlight module, or on a back surface of the backlight module facing away from the light-emitting surface, or inside the backlight module.

14. The underscreen optical fingerprint identification system of claim 13 wherein the backlight module comprises a backplane assembly for securing a light guide plate, the polarizing layer disposed on the backplane assembly.

15. The off-screen optical fingerprint identification system of claim 14 wherein the polarizing layer is at least above the detection light source such that the probe light is transmitted through the polarizing layer and the liquid crystal display to impinge on the finger;

16. The underscreen optical fingerprint recognition system of claim 14 or 15, wherein the polarizing layer is at least above the optical path directing structure such that the fingerprint detection light is incident into the optical path directing structure through the polarizing layer;

17. The underscreen optical fingerprint recognition system of claim 16, wherein the optical path directing structure comprises an optical lens layer comprising one or more aspheric lenses for focusing the fingerprint detection light onto the optical fingerprint sensor, and a polarizing layer above the optical path directing structure covers at least a field of view of the optical lens layer.

18. The underscreen optical fingerprint recognition system of claim 15 wherein a second reflective polarizing film layer and a diffusive reflective layer are further provided,

19. The underscreen optical fingerprint recognition system of claim 18 wherein the second reflective polarizing film layer is disposed on the backplane assembly and covers at least the first clear aperture.

20. The system of claim 18, further comprising a flexible circuit board (FPC) on which the detection light source is disposed, the diffuse reflection layer being disposed on a side of the flexible circuit board (FPC) facing the detection light source.

21. The underscreen optical fingerprint recognition system of claim 18 wherein the diffuse reflective layer is a white ink layer or a silver powder layer.

22. The underscreen optical fingerprint recognition system of any one of claims 12-15, wherein the detection light source, the optical path directing structure, and the optical fingerprint sensor are disposed on a center frame of the liquid crystal display.

23. A liquid crystal display panel supporting an off-screen fingerprint recognition function, wherein the below of the liquid crystal display panel is provided with the off-screen optical fingerprint recognition device according to any one of claims 1 to 11, comprising: the backlight module comprises a display module, a backlight module and a first reflective polarizing film layer positioned between the display module and the backlight module;

24. The lcd panel of claim 23, wherein the polarizing layer is disposed on a light emitting surface of the backlight module, or on a back surface of the backlight module facing away from the light emitting surface, or inside the backlight module.

25. The lcd panel of claim 24, wherein the backlight assembly comprises a back plate assembly for fixing the light guide plate, and the polarizing layer is disposed on the back plate assembly.

26. The liquid crystal display panel of claim 25, wherein the polarizing layer is at least above the detection light source to allow the probe light to pass through the polarizing layer and the liquid crystal display panel to impinge on the finger;

27. The liquid crystal display panel of claim 25 or 26, wherein the polarizing layer is at least above the light path directing structure such that the fingerprint detection light is transmitted through the polarizing layer and incident into the light path directing structure;

28. The lcd panel of claim 27, wherein the light path directing structure comprises an optical lens layer comprising one or more aspheric lenses for focusing the fingerprint detection light onto the optical fingerprint sensor, and a polarizing layer over the light path directing structure covers at least a field of view of the optical lens layer.

29. The liquid crystal display panel of claim 26, wherein a second reflective polarizing film layer and a diffusive reflective layer are further provided,

30. The liquid crystal display panel of claim 29, wherein the second reflective polarizer film layer is disposed on the backplane assembly and covers at least the first clear aperture.

31. The liquid crystal display panel according to claim 29, further comprising a flexible circuit board FPC, wherein the detection light source is provided on the flexible circuit board FPC, and wherein the diffuse reflection layer is provided on a side of the flexible circuit board FPC facing the detection light source.

32. The liquid crystal display panel of claim 29, wherein the diffuse reflective layer is a white ink layer or a silver powder layer.

33. The lcd panel of any one of claims 23-26, wherein the detection light source, the light path directing structure, and the optical fingerprint sensor are disposed on a center frame of the lcd panel.

34. An optical fingerprint identification device under screen is suitable for a liquid crystal display screen with a display module and a backlight module, wherein a first reflective polarizing film layer is arranged between the display module and the backlight module,

the optical fingerprint recognition device under screen includes: the detection light source, the light path guide structure and the optical fingerprint sensor are arranged below the backlight module; the detection light source is used for emitting detection light, part of the detection light is irradiated to a finger through the second reflection type polarizing film layer, part of the detection light is reflected by the second reflection type polarizing film layer and then is incident to the diffuse reflection layer for diffuse reflection, so that part of light after diffuse reflection is transmitted through the second reflection type polarizing film layer and is irradiated to the finger, and the light path guide structure is used for guiding fingerprint detection light which is reflected by the finger, carries fingerprint information and is transmitted through the liquid crystal display screen to the optical fingerprint sensor; the optical fingerprint sensor is used for acquiring fingerprint information of the finger according to the fingerprint detection light;

the second reflective polarizing film layer is arranged above the detection light source, and the detection light source is positioned between the diffuse reflection layer and the second reflective polarizing film layer;

35. The device for optical fingerprint identification under screen of claim 34, wherein the backlight module comprises a back plate assembly for fixing the light guide plate, and a first light through hole is disposed at a position of the back plate assembly corresponding to the detection light source, the second reflective polarizing film layer is disposed on the back plate assembly, and the second reflective polarizing film layer at least covers the first light through hole.

36. The off-screen optical fingerprint identification device according to claim 35, further comprising a polarizing layer, wherein at least one of the detection light and the fingerprint detection light is transmitted through the polarizing layer, the polarizing layer is configured to filter out S-waves in the detection light and/or the fingerprint detection light, and the polarizing layer is located above the off-screen optical fingerprint identification device;

37. The device of claim 36, wherein the polarization layer is disposed on a light emitting surface of the backlight module, or on a back surface of the backlight module facing away from the light emitting surface, or inside the backlight module.

38. The device of claim 37, wherein the polarizer layer is disposed on the back plate assembly, and the second reflective polarizing film layer is disposed between the polarizer layer and the detection light source, so that the probe light is transmitted through the second reflective polarizing film layer, the polarizer layer, and the liquid crystal display to irradiate the finger.

39. The device of claim 38, wherein a fourth fixing groove is formed in a side of the back plate assembly facing away from the light guide plate, and the polarizing layer and the second reflective polarizing film layer are sequentially stacked in the fourth fixing groove.

40. The underscreen optical fingerprint recognition device of claim 37 or 38, wherein the polarization layer is disposed on the backplane assembly, the polarization layer being at least above the light path directing structure, such that the fingerprint detection light is transmitted through the polarization layer to be incident on the light path directing structure;

41. The underscreen optical fingerprint recognition device of claim 40, wherein the optical path directing structure comprises an optical lens layer comprising one or more aspheric lenses configured to focus the fingerprint detection light onto the optical fingerprint sensor, and a polarizing layer above the optical path directing structure covers at least a field of view of the optical lens layer.

42. The underscreen optical fingerprint recognition device of any one of claims 34-38, further comprising a flexible circuit board FPC on which the detection light source is disposed, the diffuse reflection layer being disposed on a side of the flexible circuit board FPC facing the detection light source.

43. The underscreen optical fingerprint recognition device of any one of claims 34-38 wherein the diffuse reflective layer is a white ink layer or a silver powder layer.

44. The underscreen optical fingerprint recognition device of any one of claims 34-38 wherein the detection light source, the optical path directing structure, and the optical fingerprint sensor are disposed on a center frame of the liquid crystal display.

45. An off-screen optical fingerprint identification system, comprising a liquid crystal display and the off-screen optical fingerprint identification device of any one of claims 34 to 44, wherein the off-screen optical fingerprint identification device is arranged below the liquid crystal display and is used for detecting fingerprint information of a finger above the liquid crystal display.

46. The system according to claim 45, wherein the backlight module comprises a back plate assembly for fixing the light guide plate, a first light through hole is formed in a position of the back plate assembly corresponding to the detection light source, the second reflective polarizing film layer is disposed on the back plate assembly, and the second reflective polarizing film layer at least covers the first light through hole.

47. The off-screen optical fingerprint identification system of claim 46 further comprising a polarizing layer, wherein at least one of the detection light and the fingerprint detection light is transmitted through the polarizing layer, the polarizing layer is configured to filter out S-waves in the detection light and/or the fingerprint detection light, and the polarizing layer is located above the off-screen optical fingerprint identification device;

48. The system according to claim 47, wherein the polarization layer is disposed on a light emitting surface of the backlight module, or on a back surface of the backlight module facing away from the light emitting surface, or inside the backlight module.

49. The system of claim 48, wherein the polarizer layer is disposed on the backplane assembly and a second reflective polarizing film layer in the liquid crystal display is disposed between the polarizer layer and the detection light source, such that a portion of the probe light is transmitted through the second reflective polarizing film layer, the polarizer layer, and the liquid crystal display to the finger.

50. The system according to claim 49, wherein a fourth fixing groove is formed in a side of the back plate assembly facing away from the light guide plate, and the polarizing layer and the second reflective polarizing film layer are sequentially stacked in the fourth fixing groove.

51. The underscreen optical fingerprint recognition system of claim 48 or 49, wherein the polarizing layer is disposed on the backplane assembly, the polarizing layer being at least above the light path directing structure, such that the fingerprint detection light is transmitted through the polarizing layer to be incident into the light path directing structure;

52. The underscreen optical fingerprint recognition system of claim 51, wherein the optical path directing structure comprises an optical lens layer comprising one or more aspheric lenses configured to focus the fingerprint detection light onto the optical fingerprint sensor, and a polarizing layer above the optical path directing structure covers at least a field of view of the optical lens layer.

53. The underscreen optical fingerprint recognition system according to any one of claims 45-49, further comprising a flexible circuit board FPC, wherein the detection light source is disposed on the flexible circuit board FPC, and wherein the diffuse reflection layer in the liquid crystal display is disposed on a side of the flexible circuit board FPC facing the detection light source.

54. The underscreen optical fingerprint recognition system of any one of claims 45-49 wherein the diffuse reflective layer is a white ink layer or a silver powder layer.

55. The underscreen optical fingerprint recognition system of any one of claims 45-49, wherein the detection light source, the light path directing structure, and the optical fingerprint sensor are disposed on a center frame of the liquid crystal display.

56. A liquid crystal display panel supporting an off-screen fingerprint recognition function, wherein the below of the liquid crystal display panel is provided with the off-screen optical fingerprint recognition device according to any one of claims 34 to 44, comprising: the backlight module comprises a display module, a backlight module and a first reflective polarizing film layer positioned between the display module and the backlight module;

57. The liquid crystal display panel according to claim 56, wherein the backlight module comprises a back plate assembly for fixing the light guide plate, and a first light hole is formed at a position of the back plate assembly corresponding to the detection light source, the second reflective polarizing film layer is disposed on the back plate assembly, and the second reflective polarizing film layer at least covers the first light hole.

58. The lcd panel of claim 57, wherein a polarizing layer is further disposed, and at least one of the detection light and the fingerprint detection light is transmitted through the polarizing layer, the polarizing layer being configured to filter out S-waves in the detection light and/or the fingerprint detection light, and the polarizing layer being located above the under-panel optical fingerprint identification device;

59. The liquid crystal display panel according to claim 58, wherein the polarizing layer is disposed on a light emitting surface of the backlight module, or on a back surface of the backlight module facing away from the light emitting surface, or in the backlight module.

60. The liquid crystal display panel of claim 59, wherein the polarizer layer is disposed on the backplane assembly and the second reflective polarizing film layer is disposed between the polarizer layer and the detection light source such that the probe light is transmitted through the second reflective polarizing film layer, the polarizer layer, and the liquid crystal display panel to impinge on the finger.

61. The liquid crystal display panel of claim 60, wherein a side of the back plate assembly facing away from the light guide plate is provided with a fourth fixing groove, and the polarizing layer and the second reflective polarizing film layer are sequentially stacked in the fourth fixing groove.

62. The lcd panel of claim 59 or 60, wherein the polarizing layer is disposed on the backplane assembly at least above the light path directing structure such that the fingerprint detection light is transmitted through the polarizing layer and incident into the light path directing structure;

63. The liquid crystal display of claim 62, wherein the optical path directing structure comprises an optical lens layer comprising one or more aspheric lenses configured to focus the fingerprint detection light onto the optical fingerprint sensor, and wherein a polarizing layer over the optical path directing structure covers at least a field of view of the optical lens layer.

64. The liquid crystal display screen according to any of claims 56-60, further comprising a flexible circuit board FPC on which the detection light source is disposed, the diffuse reflection layer being disposed on a side of the flexible circuit board FPC facing the detection light source.

65. The liquid crystal display panel of any of claims 56-60, wherein the diffuse reflective layer is a white ink layer or a silver powder layer.

66. The lcd panel of any one of claims 56-60, wherein the detection light source, the light path directing structure, and the optical fingerprint sensor are disposed on a center bezel of the lcd panel.