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CN111095058B - Fingerprint recognition device under screen, fingerprint recognition system under screen, light guide plate assembly and liquid crystal display screen - Google Patents

Fingerprint recognition device under screen, fingerprint recognition system under screen, light guide plate assembly and liquid crystal display screen Download PDF

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Publication number
CN111095058B
CN111095058B CN201980004398.7A CN201980004398A CN111095058B CN 111095058 B CN111095058 B CN 111095058B CN 201980004398 A CN201980004398 A CN 201980004398A CN 111095058 B CN111095058 B CN 111095058B
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Prior art keywords
light guide
guide plate
light
microstructures
backlight
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CN201980004398.7A
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Chinese (zh)
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CN111095058A (en
Inventor
青小刚
李顺展
曾红林
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Shenzhen Goodix Technology Co Ltd
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Shenzhen Goodix Technology Co Ltd
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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
    • G02B6/0055—Reflecting element, sheet or layer
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133615—Edge-illuminating devices, i.e. illuminating from the side
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
    • G06V40/00—Recognition of biometric, human-related or animal-related patterns in image or video data
    • G06V40/10—Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
    • G06V40/12—Fingerprints or palmprints
    • G06V40/13—Sensors therefor
    • G06V40/1318—Sensors therefor using electro-optical elements or layers, e.g. electroluminescent sensing

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Optics & Photonics (AREA)
  • Nonlinear Science (AREA)
  • Multimedia (AREA)
  • Theoretical Computer Science (AREA)
  • Human Computer Interaction (AREA)
  • Mathematical Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Image Input (AREA)
  • Liquid Crystal (AREA)
  • Devices For Indicating Variable Information By Combining Individual Elements (AREA)

Abstract

The application provides a fingerprint recognition device and system, light guide plate subassembly and liquid crystal display screen under the screen, fingerprint recognition device under the screen is applied to the electronic equipment that has liquid crystal display screen, and fingerprint recognition device is including the fingerprint identification module that is located liquid crystal display screen's backlight unit below under the screen, and backlight unit includes the light guide plate subassembly, wherein, the light guide plate subassembly is used for highly making backlight unit and the deformation zone and the light guide plate of the adjacent rete of light guide plate keep apart through the increase of the microstructure that is located its surface to avoid fingerprint detection light to take place the film when seeing through the light guide plate subassembly and interfere, help eliminating the light guide plate and the adjacent rete of light guide plate between take place the film and interfere the phenomenon.

Description

Fingerprint recognition device under screen, fingerprint recognition system under screen, light guide plate assembly and liquid crystal display screen
Technical Field
The application relates to the technical field of biological identification, in particular to a fingerprint identification device and system under a screen, a light guide plate assembly and a liquid crystal display screen.
Background
Organic light-Emitting diodes (OLEDs for short) can control the on/off of individual pixels, and the technology of fingerprint recognition under an optical screen of an OLED screen mobile phone has entered the commercial era. The technology of identifying fingerprints under an optical screen of an electronic device (such as a mobile phone) using a Liquid Crystal Display (LCD) is being promoted to commercialization.
At present, liquid crystal display screen includes backlight unit and the display module who is located the backlight unit top, and under the general condition, backlight unit's optics diaphragm includes the reflectance coating, light guide plate, even membrane and the brightness enhancement film that stack up the setting from bottom to top, and the effect of each layer diaphragm is different. The backlight module provides uniform visible light through the backlight lamp strip, and the visible light is uniformly distributed to form a surface light source after being processed through an optical film of the backlight module so as to illuminate the display module of the liquid crystal display screen and display pictures.
However, the optical film in the backlight module is made of a polyester resin (PET for short) material, except for the light guide plate which is slightly thicker, the other films which are thinner (such as the reflective film and the light-homogenizing film) are more easily deformed, and the two films are easily in uneven contact, which easily causes the film interference phenomenon. Because the fingerprint sensor among the fingerprint identification module under the screen can receive the interference line in the film interference, and then can cause the interference to fingerprint identification's effect.
Disclosure of Invention
The application provides fingerprint recognition device and system, light guide plate subassembly and liquid crystal display screen under screen helps eliminating the light guide plate and takes place the film interference phenomenon with taking place between the adjacent rete of light guide plate.
In a first aspect, the present application provides an underscreen fingerprint identification device, which is suitable for an electronic device having a liquid crystal display screen, wherein a fingerprint identification area of the underscreen fingerprint identification device is at least partially located in a display area of the liquid crystal display screen;
the under-screen fingerprint identification device comprises a fingerprint identification module positioned below a backlight module of the liquid crystal display screen, wherein the fingerprint identification module is used for receiving fingerprint detection light which is formed by a finger above a fingerprint identification area and penetrates through the liquid crystal display screen so as to acquire a fingerprint image of the finger;
the backlight module comprises a light guide plate assembly, the light guide plate assembly comprises a light guide plate and a microstructure which is located on the surface of the light guide plate and conducts light guide on backlight of the liquid crystal display screen, the light guide plate assembly is used for enabling a deformation area of the backlight module and adjacent film layers of the light guide plate to be isolated from the light guide plate by increasing the height of the microstructure so as to avoid film interference when fingerprint detection light penetrates through the light guide plate assembly.
In a specific embodiment of this application, fingerprint identification device includes the detection light source under the screen, the detection light source is used for to being located the finger transmission probing light of fingerprint identification regional top, probing light shines the finger of fingerprint identification regional top and form and carry fingerprint information the fingerprint detects light.
In an embodiment of the present application, the detection light or the fingerprint detection light has a different wavelength from the backlight provided by the backlight module for displaying the image.
In a specific embodiment of this application, the detection light with the fingerprint detection light is the infrared light, backlight that backlight unit provided is visible light.
In a specific embodiment of this application, the deformation region of the adjacent rete of light guide plate is located backlight unit is close to one side in fingerprint identification area, wherein, deformation in the deformation region of the adjacent rete of light guide plate be with the adjacent membrane material of light guide plate is concave to the deformation of light guide plate.
In a specific embodiment of the present application, the microstructures are located on the upper surface and the lower surface of the light guide plate, and the microstructures are used to support the film material in the backlight module adjacent to the light guide plate, so that the deformation regions in the backlight module and the film layer adjacent to the light guide plate are isolated from the light guide plate.
In a specific embodiment of the present application, the micro structure includes two different light guide structures, and the light guide structures are used for guiding the backlight.
In a specific embodiment of the present application, the microstructures include a first microstructure and a second microstructure, wherein the first microstructure is located on the lower surface of the light guide plate and is used for supporting the reflective film of the backlight module, and the second microstructure is located on the upper surface of the light guide plate and is used for supporting the light homogenizing film of the backlight module.
In a specific embodiment of the present application, the first microstructures are used to scatter the backlight totally reflected in the light guide plate, so that the backlight emits light from the front side of the liquid crystal display screen; the second microstructures are used for increasing the brightness of the backlight while guiding the backlight in the light guide plate.
In a specific embodiment of the present application, a height of the first microstructure is inversely proportional to a density of a transmission area of the first microstructure on the light guide plate, wherein the transmission area is an area on the light guide plate for transmitting the fingerprint detection light.
In a specific embodiment of the present application, a density of the first microstructures in the transmissive region is less than a density of the first microstructures in a backlight guiding region of the light guide plate, or the transmissive region is a blank structure.
In one embodiment of the present application, the first microstructure is a light guide point, and the height of the first microstructure is 4.5um to 5 um.
In a specific embodiment of the present application, the light guide plate assembly is further configured to isolate the light guide plate from the deformed region of the light homogenizing film by increasing the pitch between the second microstructures.
In a specific embodiment of the present application, the second microstructures are uniformly arranged on the upper surface of the light guide plate along a straight line, and the surface of the second microstructures is an arc-shaped structure.
In a specific embodiment of this application, when the radius of curvature of second microstructure is 40um, the height of second microstructure is 2um-5um, interval between the second microstructure is 70um-90 um.
In a specific embodiment of the present application, the detection light and the fingerprint detection light are infrared light having a wavelength of 940 nm.
In a second aspect, the present application provides a light guide plate assembly suitable for supporting a liquid crystal display screen with a fingerprint identification function under a screen, the light guide plate assembly comprises a light guide plate and a microstructure which is located on the surface of the light guide plate and is used for guiding light of backlight of the liquid crystal display screen, wherein the light guide plate assembly is used for increasing the height of the microstructure to enable the liquid crystal display screen and a deformation area of an adjacent film layer of the light guide plate to be isolated from the light guide plate so as to prevent fingerprint detection light received by an optical fingerprint identification device under the screen from penetrating through the light guide plate assembly and causing film interference.
In a specific embodiment of this application, the deformation region of the adjacent rete of light guide plate is located liquid crystal display screen's backlight unit is close to one side in fingerprint identification region, wherein, the deformation in the deformation region of the adjacent rete of light guide plate be with the adjacent membrane material concavity of light guide plate is to the deformation of light guide plate.
In a specific embodiment of the present application, the microstructures are located on the upper surface and the lower surface of the light guide plate, and the microstructures are used to support the film material in the backlight module adjacent to the light guide plate, so that the deformation regions in the backlight module and the film layer adjacent to the light guide plate are isolated from the light guide plate.
In a specific embodiment of the present application, the micro structure includes two different light guide structures, and the light guide structures are used for guiding the backlight.
In a specific embodiment of the present application, the microstructures include a first microstructure and a second microstructure, wherein the first microstructure is located on the lower surface of the light guide plate and is used for supporting the reflective film of the backlight module, and the second microstructure is located on the upper surface of the light guide plate and is used for supporting the light uniformizing film of the backlight module;
the first microstructures are used for scattering the backlight totally reflected in the light guide plate so that the backlight can emit light from the front side of the liquid crystal display screen; the second microstructures are used for increasing the brightness of the backlight while guiding the backlight in the light guide plate.
In a specific embodiment of the present application, the height of the first microstructure is inversely proportional to the density of a transmission region of the first microstructure on the light guide plate, wherein the transmission region is a region on the light guide plate through which fingerprint detection light received by a fingerprint identification module of the underscreen optical fingerprint identification apparatus is transmitted.
In a specific embodiment of the present application, a density of the first microstructures in the transmissive region is less than a density of the first microstructures in a backlight guiding region of the light guide plate, or the transmissive region is a blank structure.
In one embodiment of the present application, the first microstructure is a light guide point, and the height of the first microstructure is 4.5um to 5 um.
In a specific embodiment of the present application, the light guide plate assembly is further configured to isolate the light guide plate from the deformed region of the light homogenizing film by increasing the pitch between the second microstructures.
In a specific embodiment of the present application, the second microstructures are uniformly arranged on the upper surface of the light guide plate along a straight line, and the surface of the second microstructures is an arc-shaped structure.
In a specific embodiment of this application, when the radius of curvature of second microstructure is 40um, the height of second microstructure is 2um-5um, interval between the second microstructure is 70um-90 um.
In a specific embodiment of this application, the detection light of the transmission of optical fingerprint identification device under the screen with the fingerprint detection light that the fingerprint identification module among the optical fingerprint identification device under the screen received is the infrared light that wavelength is 940 nm.
In a third aspect, the present application provides a liquid crystal display fingerprint identification system, including a liquid crystal display screen and the fingerprint identification device under the screen as described in any of the above, where the liquid crystal display screen includes a display module and a backlight module located below the display module, and the backlight module is located above the fingerprint identification module of the fingerprint identification device; the backlight module comprises the light guide plate assembly.
In a fourth aspect, the present application provides a liquid crystal display screen supporting a function of fingerprint identification under a screen, which includes a display module and a backlight module, wherein the backlight module is disposed under the display module, and is used for providing backlight for the display module, and transmitting fingerprint detection light formed by a finger above the liquid crystal display screen to the fingerprint identification module under the backlight module, wherein the backlight module includes the light guide plate assembly as described in any one of the above items.
The application provides fingerprint recognition device and system, light guide plate subassembly and liquid crystal display screen under screen, through the height of the micro-structure on the increase light guide plate, make backlight unit in with the deformation region and the light guide plate of the adjacent rete of light guide plate keep apart to avoid fingerprint detection light to take place the film when seeing through light guide plate subassembly and interfere, thereby when realizing fingerprint recognition function under the screen, can avoid because two diaphragms contact that deformation of backlight unit's optics diaphragm caused are inhomogeneous, to the interference of fingerprint identification effect, and then two diaphragms contact that have solved current backlight unit are inhomogeneous, the film interference phenomenon that leads to is to the interference problem of fingerprint identification effect.
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 a schematic structural diagram of a conventional LCD display indicating and recognizing system;
FIG. 2 is a schematic structural diagram of a conventional light guide plate assembly;
FIG. 3 is a schematic view of a conventional reflective film contacting a light guide plate;
FIG. 4 is a schematic parameter diagram of a second microstructure on a conventional light guide plate;
FIG. 5 is a schematic view of a conventional light-spreading film contacting a light guide plate;
fig. 6 is a schematic diagram illustrating a positional relationship between a first microstructure heightened reflective film on a light guide plate and the light guide plate according to an embodiment of the present application;
fig. 7 is a schematic parameter diagram of a second microstructure on a light guide plate according to an embodiment of the present disclosure;
fig. 8 is a schematic diagram illustrating a positional relationship between a light spreading film and a light guide plate according to a first embodiment of the present application;
fig. 9 is a relationship diagram of a light guide plate assembly according to an embodiment of the present application.
Description of reference numerals:
a liquid crystal display screen-10; a display module-11; display area-111; non-display area-112; a backlight module-12; a reflective film-121; a light guide plate assembly-122; a light guide plate-1221; a first microstructure-1222; a second microstructure-1223; transmissive area-1224; backlight guide area-1225; a light homogenizing film-123; a brightness enhancement film-124; steel plate-125; deformed region-126; the spacing is-L; radius of curvature-R; height-H of the second microstructure; an underscreen fingerprint identification device-20; a detection light source-21; a fingerprint identification module-22; an optical element-221; fingerprint sensor-222.
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.
As described in the background art, referring to fig. 1 to 5, the optical film of the backlight module 12 includes a reflective film 121, a light guide plate 1221, a light uniformizing film 123 and a brightness enhancement film 124 stacked from bottom to top, and the functions of the films are different. However, the optical film PET material in the backlight module 12 is the basis. However, referring to fig. 3 and fig. 5, the optical film in the backlight module 12 is slightly thicker than the light guide plate 1221, and other films are thinner, such as the reflective film 121 and the light homogenizing film 123, which are more easily deformed and are easily uneven in contact with each other, so that the film interference phenomenon is easily caused, for example, the reflective film 121 in the backlight module 12 is 80um thick, the light guide plate 1221 is about 450um thick, the light homogenizing film 123 is 50um thick, and the brightness enhancement film 124 is 70um thick.
Because the fingerprint sensor 222 in the underscreen fingerprint identification module 22 can receive the interference lines in the thin film interference, the interference to the fingerprint identification effect is further caused.
Therefore, the application provides an under-screen fingerprint identification device and system, a light guide plate assembly and a liquid crystal display screen, which can eliminate or reduce the phenomenon of thin film interference between the light guide plate 1221 and the reflection film 121 and the dodging film 123.
The embodiment of the application provides an under-screen fingerprint identification device and system, a light guide plate assembly and a liquid crystal display screen, wherein the under-screen fingerprint identification device 20 is suitable for an electronic device with the liquid crystal display screen 10, wherein the electronic device may include but is not limited to electronic products or components such as a mobile phone, a tablet computer, a television, a notebook computer, a digital photo frame, a navigator, a fingerprint lock and the like which adopt the liquid crystal display screen 10. The electronic device comprises a liquid crystal display screen 10, an off-screen fingerprint identification device 20 provided by the embodiment of the application and a light guide plate assembly 122.
In the following, the embodiment of the present application takes an application scenario of a mobile phone using the liquid crystal display screen 10 as an example, and further explains the under-screen fingerprint identification apparatus 20, the light guide plate assembly 122, the liquid crystal display fingerprint identification system, and the liquid crystal display screen 10 of the present application.
Example one
Fig. 6 is a schematic diagram illustrating a positional relationship between a first microstructure heightened on a light guide plate and a light guide plate provided in the first embodiment of the present application, fig. 7 is a schematic diagram illustrating parameters of a second microstructure on the light guide plate provided in the first embodiment of the present application, fig. 8 is a schematic diagram illustrating a positional relationship between a light homogenizing film and a light guide plate provided in the first embodiment of the present application, and fig. 9 is a schematic diagram illustrating a relationship between a light guide plate assembly provided in the first embodiment of the present application.
Referring to fig. 6 to 9, an embodiment of the present application provides an off-screen fingerprint identification apparatus 20, which is suitable for an electronic device having a liquid crystal display screen 10, wherein a fingerprint identification area (not shown) of the off-screen fingerprint identification apparatus 20 is at least partially located in a display area 111 of the liquid crystal display screen 10, so as to increase an area of the display area 111 on the liquid crystal display screen 10, thereby obtaining a better user experience. The display area 111 of the liquid crystal display screen 10 is an area for displaying a picture on the liquid crystal display screen 10 or the mobile phone. The fingerprint identification area may be specifically an area for a user to perform finger pressing to implement a fingerprint input operation.
Fingerprint identification device 20 includes fingerprint identification module 22 that is located the backlight unit 12 below of LCD screen 10 under the screen, and fingerprint identification module 22 is used for receiving the fingerprint detection light that forms and see through LCD screen 10 through the finger of fingerprint identification regional top to acquire the fingerprint image of finger.
The backlight module 12 includes a light guide plate assembly 122, the light guide plate assembly 122 includes a light guide plate 1221 and a microstructure located on the surface of the light guide plate 1221 and guiding the backlight of the lcd screen 10, wherein the light guide plate assembly 122 is configured to isolate the light guide plate 1221 from the deformation area 126 of the adjacent film layer of the light guide plate 1221 in the backlight module 12 by increasing the height of the microstructure, so as to avoid the film interference of the fingerprint detection light when the fingerprint detection light penetrates through the light guide plate assembly 122.
Specifically, in the present embodiment, the light guide plate assembly 122 may be an integrated structure. In this embodiment, the light guide plate 1221 and the microstructure may be an integrated structure formed by injection molding or other integrally forming methods. The light guide plate 1221 and the microstructures may be made of one or more materials (e.g., PEF) that can guide the backlight (e.g., visible light) of the lcd screen 10, and in this embodiment, the specific forming manner and material of the light guide plate assembly 122 are not further limited.
Referring to fig. 1, the backlight assembly 12 may include an optical film assembly and a steel plate 125 under and supporting the optical film assembly. The optical film assembly may specifically include a light guide plate assembly 122, a light homogenizing film 123 and a brightness enhancement film 124 located on a light exit surface (i.e., a top surface) of the light guide plate assembly 122, and a reflective film 121 located on a bottom surface of the light guide plate 1221. In addition, the backlight module 12 may further include a backlight source (not shown), and the backlight source may be specifically disposed on one side surface of the light guide plate assembly 122, that is, a side surface of the light guide plate assembly 122 facing the backlight source is used as a light incident surface. The light guide plate assembly 122 is mainly used for receiving backlight provided by the backlight source through the light incident surface, converting the backlight into uniform planar light and emitting the uniform planar light from the light emitting surface; the reflective film 121 is mainly used to reflect the backlight emitted from the bottom surface of the light guide plate assembly 122 back to the light guide plate assembly 122; the light homogenizing film 123 and the brightness enhancement film 124 are respectively used for performing light homogenizing diffusion and brightness enhancement processing on the planar light emitted from the light emitting surface of the light guide plate assembly 122. The steel plate 125 is mainly used for supporting and protecting other optical films of the backlight module 12. As described in the background art, since the optical film layer of the backlight module 12 is made of PET material, and the light uniformizing film 123 and the reflective film 121 are thin, they are easy to deform, so that the deformed region 126 (i.e. the deformed region facing the side of the light guide plate assembly 122) of the reflective film 121 or the light uniformizing film 123 contacts the light guide plate 1221 unevenly. The uneven contact between the deformed area 126 of the reflective film 121 or the light homogenizing film 123 and the light guide plate 1221 can be caused by different contact degrees between the reflective film 121 or the light homogenizing film 123 and the light guide plate 1221 in the deformed area 126, which results in different gaps between the reflective film 121 or the light homogenizing film 123 and the light guide plate 1221 in the periphery of the contact point in the deformed area 126.
Specifically, as shown in fig. 1 to 5, when the reflective film 121 or the light uniformizing film 123 deforms on the side facing the light guide plate 1221, although the microstructures on the existing light guide plate 1221 can support the reflective film 121 or the light uniformizing film 123, the microstructures on the existing light guide plate 1221 do not support the reflective film 121 or the light uniformizing film 123 sufficiently, so that the deformation region 126 of the reflective film 121 or the light uniformizing film 123 still comes into uneven contact with the light guide plate 1221.
Because fingerprint identification module 22 detects the light through receiving the fingerprint that passes through whole LCD screen 10 and carry fingerprint information, realizes reading of fingerprint image. So when fingerprint detection light passes through the deformation region 126 of this backlight unit 12, because the deformation region 126 contact light guide plate 1221 inhomogeneous of reflectance coating 121 and/or even light film 123, fingerprint detection light is at the reflection and transmission phenomenon mutual interference in this deformation region 126, make light guide plate 1221 and its adjacent rete between (for example reflectance coating 121 and even light film 123) film interfere, and fingerprint sensor 222 in fingerprint identification module 22 can receive the line (for example newton ring or other interference lines) that have the interference to fingerprint formation in the film interference, and then can cause certain degree of interference to fingerprint identification's effect.
For example, the fingerprint sensor 222 may receive newton's rings or other interference patterns (e.g., fringe interference patterns), such that the fingerprint image is covered by the newton's rings or other interference patterns, thereby affecting the fingerprint image acquisition or identification. Or, the fingerprint sensor 222 receives the fingerprint detection light carrying the fingerprint information and also receives newton's rings or other interference patterns, and because the fingerprint sensor 222 processes the fingerprint information according to a certain algorithm after receiving the fingerprint information carried on the fingerprint detection light to form fingerprint imaging, the newton's rings or other interference patterns received by the fingerprint sensor 222 generate certain interference to the fingerprint imaging process, thereby affecting the fingerprint identification effect.
It should be noted that newton rings or other interference patterns are a thin film interference phenomenon. Newton's rings are concentric rings of alternating light and dark circles, which are an interference pattern of light. The Newton rings are typical equal-thickness thin film interference, namely the thickness of air films at the rings with the same radius is the same, and the reflection optical path difference of the upper surface and the lower surface is the same, so that the forming condition of the Newton rings is harsher than that of other interference grains (such as fringe interference grains) in the application.
For this reason, as shown in fig. 6 to 8, in the present application, by increasing the height of the microstructure on the light guide plate 1221, the microstructure plays a better supporting effect on the reflective film 121 and the uniform light film 123, and achieves the purpose that even if the reflective film 121 and the uniform light film 123 deform, the microstructure cannot contact the light guide plate 1221, that is, the deformation region 126 (i.e., the reflective film 121 and the uniform light film 123) of the adjacent film layers of the backlight module 12 and the light guide plate 1221 is isolated from the light guide plate 1221, so as to avoid the condition of newton ring or other interference patterns, so as to avoid the thin film interference of fingerprint detection light when penetrating through the light guide plate assembly 122, thereby eliminating the thin film interference phenomenon possibly caused by deformation of the reflective film 121 and the uniform light film 123. Consequently, when this application realized fingerprint identification function under the screen, can avoid because two diaphragms contact that deformation of backlight unit 12's optics diaphragm caused are inhomogeneous, to the interference of fingerprint identification effect, and then solved two diaphragms contact inhomogeneous of current backlight unit 12, the film interference phenomenon that leads to is to the interference problem of fingerprint identification effect.
Specifically, in this embodiment, referring to fig. 1, the device for identifying a fingerprint under a screen 20 may further include a detection light source 21, where the detection light source 21 is configured to emit detection light to a finger located above the fingerprint identification area, and the detection light irradiates the finger above the fingerprint identification area and forms fingerprint detection light carrying fingerprint information after the finger reflects or transmits the detection light. The fingerprint detection light further passes through the liquid crystal display screen 10 and returns to the fingerprint identification module 22. In order to ensure that the fingerprint detection light carrying the fingerprint information can pass through the lcd screen 10, in the embodiment, at least a partial region of the backlight module 12 is a light-transmitting region (not labeled in the figure) through which the fingerprint detection light can pass, the light-transmitting region may specifically be a region corresponding to the transmission path of the detection light source 21 and the fingerprint detection light formed by the finger on the lcd screen 10, and the transmission waveband covers the emission waveband of the detection light source 21, so that the detection light and the fingerprint detection light formed by the finger can pass through the light-transmitting region of the backlight module 12. The fingerprint identification module 22 is located below the light-transmitting area of the liquid crystal display screen 10 so as to receive the fingerprint detection light returned by the light-transmitting area passing through the backlight module 12, and can acquire the fingerprint image of the finger according to the fingerprint information carried by the fingerprint detection light.
As a possible implementation manner, in the present embodiment, the detection light source 21 may be located below the backlight module 12 and disposed close to the fingerprint identification module 22 or integrated inside the fingerprint identification module 22. Alternatively, in this embodiment, the detection light source 21 may be disposed in the non-display area 111 of the liquid crystal display screen 10 together with the backlight light source of the backlight module 12. Or, the detection light source 21 may also be disposed at other positions, in this embodiment, the position of the detection light source 21 is not further limited, and it is only required to ensure that the detection light emitted by the detection light source 21 can irradiate the finger above the fingerprint identification area of the display module 11, and the fingerprint detection light formed by reflection or transmission of the finger can enter the fingerprint identification module 22 through the light-transmitting area (not marked in the figure) of the backlight module 12.
In order to avoid the interference of the detection light emitted by the detection light source 21 on the display effect of the liquid crystal display screen 10, in this embodiment, the detection light or the fingerprint detection light has a wavelength different from that of the backlight provided by the backlight module 12 and used for displaying the image, that is, the detection light source 21 may specifically be a light source having a different wavelength band from that of the backlight provided by the backlight module 12 and used for emitting the detection light of a specific wavelength band, and the detection light of the specific wavelength band is used for the fingerprint identification module 22 to perform the optical fingerprint detection under the screen. The detection light of the specific wavelength band may be invisible light outside the visible wavelength band, such as infrared light.
For example, in this embodiment, the backlight provided by the backlight module 12 may be visible light, and the detection light and the fingerprint detection light may be infrared light or other light signals with wavelengths outside the wavelength band of the visible light and capable of realizing fingerprint identification. Thus, the user cannot see or perceive the above-mentioned detection light for fingerprint recognition through the display module 11. Therefore, the fingerprint identification module 22 of the embodiment of the present application not only can utilize the fingerprint detection light that passes the backlight module 12 to realize optical fingerprint detection under the screen, but also can reduce the display effect of the detection light liquid crystal display screen 10 that the detection light source 21 sends and cause interference, and avoid influencing the display effect of the image.
Specifically, the detection light source 21 may be an infrared light source such as an infrared lamp, an infrared Vertical Cavity Surface Emitting Laser (VCSEL, for short), or an infrared Laser Diode (Laser Diode).
In the present embodiment, the spectral range of the detection light emitted from the detection light source 21 may be 780nm to 1100 nm. Preferably, it may be infrared light having a wavelength of 940 nm. Utilize the characteristics that visible light and infrared light are different in backlight module 12's all kinds of membrane materials in a poor light like this, can guarantee that the fingerprint detection light that carries fingerprint information distorts for a short time in backlight module 12's transmission course, ensures that the fingerprint identification accuracy is high. On the other hand, the infrared light emitted by the detection light source 21 is used as the detection light, and the penetration capability of the infrared light is stronger than that of the visible light, so that the signal of the fingerprint detection light penetrating through the liquid crystal display screen 10 and each backlight film thereof can be more effectively enhanced, and the fingerprint identification effect is improved.
Specifically, in this embodiment, the fingerprint identification module 22 may include an optical element 221, a filter (not labeled in the figure) and a fingerprint sensor 222, wherein the filter is located between the optical element 221 and the fingerprint sensor 222, the optical element 221 faces one side of the backlight module 12, and the optical element 221 is configured to enable the fingerprint detection light passing through the backlight module 12 to pass through the optical path guide of the optical element 221 or optically converge and enter the fingerprint sensor 222 to implement optical imaging of the fingerprint image. The fingerprint sensor 222 may also be referred to as an optical sensor, an image sensor, an optical fingerprint sensor 222, an optical sensor, a fingerprint detection sensor, or the like, and may specifically include an optical imaging chip, or an optical imaging chip having an optical stack with an optical sensing array of a plurality of optical sensing elements for receiving and photoelectrically converting fingerprint detection light. The filter filters out other infrared light or interference light outside the wave band of the fingerprint detection light to eliminate the interference of the light entering the fingerprint sensor 222 on fingerprint identification, thereby improving the fingerprint identification effect.
Specifically, the optical filter may be located above the fingerprint sensor 222, or may be directly formed on the optical sensing array or the optical path guiding structure of the fingerprint sensor 222 by coating. For example, in the present embodiment, the Filter includes, but is not limited to, an infrared Cut Filter (IR-Cut Filter, abbreviated as IRCF).
The optical element 221 may include a macro lens having at least one spherical or aspheric lens, and a physical component for carrying the macro lens, and the fingerprint sensor 222 and the optical filter above the fingerprint sensor may be located in a converging optical path of the macro lens to realize optical imaging of a fingerprint.
In the following, the light guide plate assembly 122 in the embodiment of the present application is further described by taking infrared light with a wavelength of 940nm as an example. The detection light of the transmission of optical fingerprint identification device under the screen and the fingerprint detection light received by the fingerprint identification module 22 in the optical fingerprint identification device under the screen are infrared light with wavelength of 940 nm.
Referring to fig. 6 to 9, an embodiment of the present application provides a light guide plate assembly 122, which is suitable for a liquid crystal display screen 10 supporting an underscreen fingerprint identification function, where the light guide plate assembly 122 includes a light guide plate 1221 and microstructures located on a surface of the light guide plate 1221 and guiding light to a backlight of the liquid crystal display screen 10. In order to make the micro-structure play better support effect to reflectance coating 121 and even light membrane 123, through the height of micro-structure on the increase light guide plate 1221, so that the deformation region 126 (reflectance coating 121 and even light membrane 123) and the light guide plate 1221 of the adjacent rete of backlight unit 12 and light guide plate 1221 keep apart, thereby avoid falling the condition that newton's ring or other interference line produced, take place the film interference when seeing through light guide plate subassembly 122 with the fingerprint detection light that fingerprint sensor 222 accepted in the fingerprint identification module 22, interference to the fingerprint identification effect.
Specifically, in this embodiment, the deformation area 126 of the adjacent film layer of the light guide plate 1221 is located on one side of the backlight module 12 close to the fingerprint identification area, wherein the deformation in the deformation area 126 of the adjacent film layer of the light guide plate 1221 is the deformation of the film material adjacent to the light guide plate 1221 concave toward the light guide plate 1221 (as shown in fig. 3 and 5). Therefore, when the film material adjacent to the light guide plate 1221 is deformed, the deformed region 126 thereof is recessed toward the light guide plate 1221 to allow for thin-film interference with the light guide plate 1221.
Specifically, referring to fig. 6 to 9, in the present embodiment, the microstructures are located on the upper surface and the lower surface of the light guide plate 1221, and the microstructures are used to support the film material of the backlight module 12 adjacent to the light guide plate 1221, so that the deformation regions 126 of the film layer of the backlight module 12 adjacent to the light guide plate 1221 are isolated from the light guide plate 1221. Meanwhile, the microstructures on the light guide plate 1221 can guide the backlight (visible light) better, and convert the backlight into uniform planar light to illuminate the liquid crystal display screen 10.
Further, referring to fig. 6 to 9, in the present embodiment, the microstructures include two light guide structures with different structures, and the light guide structures are used for guiding the backlight. The microstructures include a first microstructure 1222 and a second microstructure 1223, wherein the first microstructure 1222 is located on the lower surface of the light guide plate 1221 and is used to support the reflective film 121 of the backlight module 12, and the second microstructure 1223 is located on the upper surface of the light guide plate 1221 and is used to support the light uniformizing film 123 of the backlight module 12. Specifically, in this embodiment, the first microstructures 1222 and the second microstructures 1223 can support the reflective film 121 and the light uniformizing film 123 to a certain extent, so as to isolate the deformed regions 126 of the reflective film 121 and the light uniformizing film 123 from the light guide plate 1221. The first microstructures 1222 are used to diffuse the backlight totally reflected by the reflective film 121 in the light guide plate 1221, so that the backlight emits light from the front of the liquid crystal display screen 10; the second microstructures 1223 serve to increase the luminance of the backlight while guiding the backlight within the light guide plate 1221. The present embodiment converts the backlight into uniform planar light through the light guide plate assembly 122 to illuminate the liquid crystal display screen 10 for display of the liquid crystal display screen 10.
It is understood that, on the basis of the unchanged structure of the first microstructures 1222, the greater the density of the first microstructures 1222 on the light guide plate 1221, the stronger the supporting effect on the reflective film 121. Therefore, in the present embodiment, the height of the first microstructure 1222 is inversely proportional to the density of the transmissive area 1224 of the first microstructure 1222 on the light guide plate 1221, that is, the greater the density of the first microstructure 1222 in the transmissive area 1224, the smaller the height of the first microstructure 1222, and conversely, the smaller the density of the first microstructure 1222 in the transmissive area 1224, the larger the height of the first microstructure 1222. Wherein, refer to fig. 2 and show, transmission area 1224 is the area that is used for making fingerprint detection light to see through on the light guide plate 1221, that is to say, transmission area 1224 mainly used can see through light guide plate 1221 and get into fingerprint identification module 22 smoothly at the fingerprint detection light that carries fingerprint information that the finger formed, thereby realizes fingerprint identification, the fingerprint detection light of avoiding carrying fingerprint information is influenced by the light path guide of light guide plate 1221 and can't normally get into fingerprint identification module 22 and cause the fingerprint image distortion. Alternatively, in particular embodiments, the fingerprint recognition module 22 may be located at least partially vertically below the transmissive areas 1224 of the light guide panel 1221203.
Since the backlight strip is disposed near one side (i.e., the light incident surface) of the light guide plate 1221 and near the fingerprint identification region, considering that there is a certain loss of the backlight during the transmission process, in order to make the display effect of the lcd screen 10 have a certain uniformity (i.e., the display brightness is substantially uniform), in this embodiment, the first microstructures 1222 are unevenly distributed on the light guide plate 1221 (as shown in fig. 2, the density of the first microstructures 1222 increases gradually in a direction away from the backlight light source). The density of the first microstructures 1222 in the transmissive area 1224 is less than that of the first microstructures 1222 in the backlight guiding area 1225 of the light guiding plate 1221, or the transmissive area 1224 is a blank structure, i.e. the first microstructures 1222 are not disposed in the transmissive area 1224 (as shown in fig. 2), so as to increase the transmittance of the transmissive area 1224 for the fingerprint detection light carrying the fingerprint information. The backlight guiding area 1225 is configured to convert visible light provided by the backlight source into planar light emitted from a light emitting surface of the light guide plate 1221 near the display module 11, so as to illuminate the display module 11, and ensure that the backlight module 12 can normally provide backlight. Since the density of the first microstructures 1222 on the light guide plate 1221 is changed, the display effect of the lcd screen 10 may be affected (the display may be locally excessive or too dark). Therefore, the embodiment of the present application isolates the deformed regions 126 (the reflective film 121 and the light uniformizing film 123) of the adjacent film layers of the backlight module 12 and the light guide plate 1221 from the light guide plate 1221 by increasing the height of the first microstructures 1222.
Specifically, in this embodiment, the first microstructures 1222 can be a light guide point, which is also called a light guide dot, specifically, the light guide point can be a plastic particle, a particle with high reflection for backlight, or other micro particles capable of changing light and diffusing light to various angles, that is, in this embodiment, the light guide point includes but is not limited to a plastic particle. Referring to fig. 6, compared to the height (3um) of the light guide point at the bottom of the light guide plate 1221 in the prior art, the height of the first microstructures 1222 in this embodiment is 4.5um-5 um. When the height of the first microstructures 1222 is less than 4.5um, the supporting strength of the reflective film 121 is insufficient, the deformed region 126 of the reflective film 121 may contact the light guide plate 1221 unevenly, when the height of the first microstructure 1222 is greater than 5um, the first microstructure 1222 may be displayed on the liquid crystal display screen 10, and therefore, to secure the display effect of the liquid crystal display screen 10 while isolating the deformed region 126 of the reflective film 121 from the light guide plate 1221, the height of the first microstructures 1222 is limited to the above range, when the height of the first microstructure 1222 is within the above range, the distance L between the deformed region 126 of the reflective film 121 and the light guide plate 1221 is greater than half of the wavelength of the detection light (e.g., 940nm), and when the detection light is irradiated into the deformed region 126, the projection and reflection of the detection light are less interfered, so that the occurrence of thin film interference is effectively avoided.
Since the thickness of the light uniformizing film 123 is 50um, it is easily deformed, and the contact surface with the light guide plate assembly 122 is smooth, which also causes the problem of thin film interference. On the basis of the above, referring to fig. 7, in the present embodiment, the light guide plate assembly 122 is further configured to isolate the light guide plate 1221 from the deformed region 126 of the light uniformizing film 123 by increasing the spacing L between the second microstructures 1223, so as to destroy the condition of the thin-film interference between the light guide plate 1221 and the deformed region 126 of the light uniformizing film 123.
Referring to fig. 7 to 9, in the embodiment, the second microstructures 1223 are uniformly arranged on the upper surface of the light guide plate 1221 along a straight line, and the surface of the second microstructures 1223 is an arc-shaped structure. When the radius of curvature R of the second microstructures 1223 is 40um, compared to the prior art in which the height H of the second microstructures is 1um and the distance L is generally 40um, in this embodiment, the height H of the second microstructures is 2um to 5um, such as 3um and 4um, and the distance L between the second microstructures 1223 is 70um to 90um, such as 80 um. Accordingly, when the height H of the second microstructure is greater than 5um, the second microstructure 1223 may be displayed on the liquid crystal display screen 10 due to the increase of the second microstructure 1223, so as to affect the display effect of the liquid crystal display screen 10. Therefore, in order to ensure the display effect of the liquid crystal display screen 10 while isolating the deformed region 126 of the light uniformizing film 123 from the light guide plate 1221, the height H and the pitch L of the second microstructures are limited to the above range, and when the height H and the pitch L of the second microstructures are in the above range, the pitch L between the deformed region 126 of the light uniformizing film 123 and the light guide plate 1221 is greater than half of the wavelength of the probe light (for example, 940nm), and at this time, when the probe light is irradiated into the deformed region 126, the interference of the projection and reflection action of the probe light is less, so that the occurrence of the thin film interference is effectively avoided.
Specifically, the second microstructures 1223 may be arc-shaped light guide structures having light guide performance for backlight, the arc-shaped light guide structures may be made of plastic or a material having high reflection for backlight, and the arc-shaped light guide structures may be made of the same material as the first microstructures 1222 and the light guide plate 1221 by injection molding or other integrally forming processes, in this embodiment, the material of the second microstructures 1223 is not further limited.
The application provides a fingerprint recognition device under screen, through the height of the micro-structure on the increase light guide plate, make the deformation region and the light guide plate isolation of the adjacent rete of light guide plate in the backlight unit to avoid fingerprint detection light to take place the film when seeing through the light guide plate subassembly and interfere, thereby when the fingerprint recognition function is under the realization screen, can avoid because the interference problem of the deformation of backlight unit's optics diaphragm to the fingerprint identification effect.
Example two
On the basis of the first embodiment, the embodiment of the present application provides a liquid crystal display fingerprint identification system, including a liquid crystal display screen 10 and an under-screen fingerprint identification device 20 as in the first embodiment, where the liquid crystal display screen 10 includes a display module 11 and a backlight module 12 located below the display module 11, and the backlight module 12 is located above a fingerprint identification module 22 of the fingerprint identification device; the backlight module 12 includes the light guide plate assembly 122 in the above embodiment.
Specifically, in this embodiment, reference may be made to the description of the first embodiment on the underscreen fingerprint identification device 20 and the light guide plate assembly 122, and in this embodiment, no further description is given to the underscreen fingerprint identification device 20 and the light guide plate assembly 122.
The lcd screen 10 generally includes the backlight unit 12 of display module 11 below, fingerprint identification module 22 is located under backlight unit 12, be formed with the light transmission area that is used for making the fingerprint detect the light transmission on backlight unit 12, the light transmission area can be said that backlight unit 12's relevant optics rete subassembly forms the region that the wave band about the fingerprint detects the light at the transmission path of surveying the light and fingerprint is printing opacity, fingerprint identification module 22 is located under backlight unit 12's light transmission area, so that the fingerprint detects the light and transmits to fingerprint identification module 22 through backlight unit 12.
Specifically, in this embodiment, the light-transmitting area may be an area corresponding to a transmission path of the fingerprint detection light on the lcd screen 10, and the transmission waveband of the detection light covers the reflection waveband of the detection light, so that the detection light and the fingerprint detection light formed by the detection light on the finger can penetrate through the light-transmitting area of the backlight module 12.
It should be noted that, in practical application, can adjust the relative position between the detection light source, backlight unit's light transmission area and the fingerprint identification module as required, but the relative position between the detection light source 21 after the adjustment, backlight unit's light transmission area and the fingerprint identification module, the finger that the detection light that needs to satisfy the emission of detection light source 21 can shine the fingerprint identification area top, and the fingerprint detection light that forms through finger reflection or transmission can get into fingerprint identification module 22 through the light transmission area of backlight unit 12.
The application provides a liquid crystal display fingerprint identification system, through the height of the micro-structure on the increase light guide plate, make the deformation region and the light guide plate of the adjacent rete of light guide plate keep apart in the backlight unit to avoid fingerprint detection light to take place the film when seeing through the light guide plate subassembly and interfere, thereby when realizing the fingerprint identification function under the screen, can avoid because the interference problem of the deformation of backlight unit's optics diaphragm to the fingerprint identification effect.
EXAMPLE III
On the basis of the first embodiment, the embodiment of the present application provides a liquid crystal display screen 10 supporting the function of fingerprint identification under the screen, which includes a display module 11 and a backlight module 12, wherein the backlight module 12 is disposed under the display module 11 and is used for providing backlight for the display module 11 and transmitting the fingerprint detection light formed by the finger above the liquid crystal display screen 10 to the fingerprint identification module 22 under the backlight module 12. Fingerprint identification device 20 is including detecting light source 21 and fingerprint identification module 22 under the screen, wherein, detects light source 21 and is used for emitting the probe light to the finger that is located the regional top of fingerprint identification, the probe light shines the finger of the regional top of fingerprint identification and finger reflection or forms the fingerprint detection light that carries fingerprint information after the transmission, fingerprint identification module 22 is used for receiving the fingerprint detection light that sees through liquid crystal display screen 10 and carry fingerprint information to acquire the fingerprint image of finger. Wherein the backlight module 12 comprises the light guide plate assembly 122 as described above. Specifically, in the present embodiment, reference may be made to the description of the light guide plate assembly 122 in the first embodiment, and in the present embodiment, no further description is made on the light guide plate assembly 122.
The application provides a support liquid crystal display screen of fingerprint identification function under screen, through the height of the micro-structure on the increase light guide plate, make the deformation zone of the adjacent rete of light guide plate in the backlight unit keep apart with the light guide plate to avoid fingerprint detection light to take place the film when seeing through the light guide plate subassembly and interfere, thereby can avoid because the interference problem of the deformation of backlight unit's optical film piece to the fingerprint identification effect.
In the description of the present application, it should be noted that unless otherwise specifically stated or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may for example be fixed or indirectly connected through intervening media, or may be interconnected between two elements or may be in the interactive relationship between two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.
In the description of the present application, it is to be understood that the terms "upper", "lower", "front", "back", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present application and simplifying the description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present application. In the description of the present application, "a plurality" means two or more unless specifically stated otherwise.
The terms "first," "second," "third," "fourth," and the like in the description and in the claims of the present application and in the drawings described above, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
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 (30)

1. An under-screen fingerprint identification device is suitable for an electronic device with a liquid crystal display screen, and is characterized in that a fingerprint identification area of the under-screen fingerprint identification device is at least partially positioned in a display area of the liquid crystal display screen;
the under-screen fingerprint identification device comprises a fingerprint identification module positioned below a backlight module of the liquid crystal display screen, wherein the fingerprint identification module is used for receiving fingerprint detection light which is formed by a finger above a fingerprint identification area and penetrates through the liquid crystal display screen so as to acquire a fingerprint image of the finger;
the backlight module comprises a light guide plate assembly, the light guide plate assembly comprises a light guide plate and microstructures which are located on the upper surface and the lower surface of the light guide plate and conduct light guide on backlight of the liquid crystal display screen, the light guide plate and the microstructures are integrally formed, the light guide plate assembly is used for enabling deformation areas of adjacent film layers of the backlight module and the light guide plate to be isolated from the light guide plate by increasing the heights of the microstructures, and therefore film interference of fingerprint detection light when the fingerprint detection light penetrates through the light guide plate assembly is avoided.
2. The device according to claim 1, wherein the device comprises a detection light source for emitting a detection light to a finger above the fingerprint identification area, wherein the detection light irradiates the finger above the fingerprint identification area and forms the fingerprint detection light carrying fingerprint information.
3. The device according to claim 2, wherein the detection light or the fingerprint detection light has a different wavelength from the backlight provided by the backlight module for displaying the image.
4. The device according to claim 3, wherein the detection light and the fingerprint detection light are both infrared light, and the backlight provided by the backlight module is visible light.
5. The device according to claim 1, wherein the deformation region of the adjacent film layer of the light guide plate is located on one side of the backlight module close to the fingerprint identification region, and the deformation in the deformation region of the adjacent film layer of the light guide plate is the deformation of the film material adjacent to the light guide plate concave to the light guide plate.
6. The device according to any one of claims 1 to 5, wherein the microstructures are configured to support a film in the backlight module adjacent to the light guide plate, so that the deformed regions in the backlight module and the film adjacent to the light guide plate are isolated from the light guide plate.
7. The device of claim 6, wherein the microstructures comprise two different light guide structures for guiding the backlight.
8. The device according to claim 7, wherein the microstructures comprise a first microstructure and a second microstructure, wherein the first microstructure is located on the lower surface of the light guide plate and is used for supporting the reflective film of the backlight module, and the second microstructure is located on the upper surface of the light guide plate and is used for supporting the light homogenizing film of the backlight module.
9. The device according to claim 8, wherein the first microstructures are configured to scatter the backlight totally reflected in the light guide plate, so that the backlight emits light from the front of the lcd screen; the second microstructures are used for guiding light and brightening the backlight in the light guide plate.
10. The device of claim 8, wherein the height of the first microstructures is inversely proportional to the density of the transmission regions of the first microstructures on the light guide plate, wherein the transmission regions are regions of the light guide plate for transmitting the fingerprint detection light.
11. The device of claim 10, wherein the density of the first microstructures in the transmissive region is less than the density of the first microstructures in the backlight guiding region of the light guide plate, or the transmissive region is a blank structure.
12. The device of any one of claims 8-11, wherein the first microstructure is a light guide point and the height of the first microstructure is 4.5um-5 um.
13. The underscreen fingerprint identification device of claim 12, wherein the light guide plate assembly is further configured to isolate the light guide plate from the deformed region of the light distribution film by increasing a spacing between the second microstructures.
14. The device of claim 13, wherein the second microstructures are uniformly arranged on the upper surface of the light guide plate along a straight line, and the surface of the second microstructures is of an arc-shaped structure.
15. The device of claim 13 or 14, wherein when the radius of curvature of the second microstructures is 40um, the heights of the second microstructures are 2um to 5um, and the distances between the second microstructures are 70um to 90 um.
16. The device of claim 4, wherein the detection light and the fingerprint detection light are both infrared light having a wavelength of 940 nm.
17. The utility model provides a light guide plate subassembly, is applicable to the liquid crystal display screen who supports fingerprint identification function under the screen, its characterized in that, light guide plate subassembly includes the light guide plate and is located light guide plate upper surface and lower surface and right the microstructure that liquid crystal display screen's backlight leaded light carries out, the light guide plate with microstructure integrated into one piece, wherein, light guide plate subassembly is used for making through the increase height of microstructure the deformation region of in the liquid crystal display screen with the adjacent rete of light guide plate with the light guide plate is kept apart to avoid being seen through by the fingerprint detection light that optical fingerprint identification device received under the screen takes place the film when seeing through light guide plate subassembly and interferes.
18. The light guide plate assembly of claim 17, wherein the deformation region of the light guide plate adjacent film layer is located on a side of the backlight module of the lcd screen close to the fingerprint identification region, wherein the deformation in the deformation region of the light guide plate adjacent film layer is a deformation of a film material adjacent to the light guide plate concave to the light guide plate.
19. The light guide plate assembly of claim 18, wherein the microstructures are configured to support the film in the backlight module adjacent to the light guide plate to isolate the deformed regions of the film in the backlight module and adjacent to the light guide plate from the light guide plate.
20. The light guide plate assembly of any of claims 17-19, wherein the microstructures comprise two different structures of light guide structures for guiding the backlight.
21. The light guide plate assembly of claim 20, wherein the microstructures comprise a first microstructure and a second microstructure, wherein the first microstructure is located on a lower surface of the light guide plate and is used for supporting the reflective film of the backlight module, and the second microstructure is located on an upper surface of the light guide plate and is used for supporting the dodging film of the backlight module;
the first microstructures are used for scattering the backlight totally reflected in the light guide plate so that the backlight can emit light from the front side of the liquid crystal display screen; the second microstructures are used for increasing the brightness of the backlight while guiding the backlight in the light guide plate.
22. The light guide plate assembly of claim 21, wherein the height of the first microstructures is inversely proportional to the density of the transmissive areas of the first microstructures on the light guide plate, wherein the transmissive areas are areas on the light guide plate for transmitting fingerprint detection light received by the fingerprint identification module of the underscreen optical fingerprint identification device.
23. The light guide plate assembly of claim 22, wherein the density of the first microstructures in the transmissive region is less than the density of the first microstructures in a backlight guiding region of the light guide plate, or the transmissive region is a blank structure.
24. The light guide plate assembly of any of claims 21-23, wherein the first microstructures are light guide points and the first microstructures have a height of 4.5um to 5 um.
25. The light guide plate assembly of any one of claims 21-23, wherein the light guide plate assembly is further configured to isolate the light guide plate from the deformed region of the light homogenizing film by increasing a spacing between the second microstructures.
26. The light guide plate assembly of claim 25, wherein the second microstructures are uniformly arranged along a straight line on the upper surface of the light guide plate, and the surface of the second microstructures has an arc-shaped structure.
27. The light guide plate assembly of claim 26, wherein the second microstructures have a height of 2um to 5um and a pitch of 70um to 90um when the radius of curvature of the second microstructures is 40 um.
28. The light guide plate assembly of claim 27, wherein the detection light emitted by the underscreen optical fingerprint identification device and the detection light received by the fingerprint identification module in the underscreen optical fingerprint identification device are both infrared light with a wavelength of 940 nm.
29. A liquid crystal display fingerprint identification system, comprising a liquid crystal display screen and the under-screen fingerprint identification device of any one of claims 1 to 16, wherein the liquid crystal display screen comprises a display module and a backlight module positioned below the display module, and the backlight module is positioned above the fingerprint identification module of the fingerprint identification device; wherein the backlight module comprises the light guide plate assembly of any one of claims 17-28.
30. A liquid crystal display screen supporting an under-screen fingerprint recognition function, comprising a display module and a backlight module, wherein the backlight module is disposed below the display module and used for providing backlight for the display module and transmitting fingerprint detection light formed by a finger above the liquid crystal display screen to the fingerprint recognition module below the backlight module, wherein the backlight module comprises the light guide plate assembly according to any one of claims 17 to 28.
CN201980004398.7A 2019-11-20 2019-11-20 Fingerprint recognition device under screen, fingerprint recognition system under screen, light guide plate assembly and liquid crystal display screen Active CN111095058B (en)

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