WO2021196034A1

WO2021196034A1 - Under-screen fingerprint identification apparatus, backlight module, liquid crystal display screen, and electronic device

Info

Publication number: WO2021196034A1
Application number: PCT/CN2020/082604
Authority: WO
Inventors: 廖志川; 青小刚; 李家成
Original assignee: 深圳市汇顶科技股份有限公司
Priority date: 2020-03-31
Filing date: 2020-03-31
Publication date: 2021-10-07

Abstract

The present application provides an under-screen fingerprint identification apparatus, a backlight module, a liquid crystal display screen, and an electronic device. The under-screen fingerprint identification apparatus is suitable for an electronic device having a liquid crystal display screen. The apparatus comprises a fingerprint identification module positioned below a backlight module of the liquid crystal display screen; the backlight module comprises a diffusion film, a light guide plate, and a reflective film; the light guide plate is adjacently arranged below the diffusion film; the surface, facing the light guide plate, of the diffusion film is provided with a plurality of first microstructures arranged at intervals; the first microstructures are randomly distributed on the lower surface of the diffusion film and used for increasing the distance between the diffusion film and the light guide plate; the reflective film is adjacently arranged below the light guide plate; the surface, facing the light guide plate, of the reflective film is provided with a plurality of second microstructures arranged at intervals; the second microstructures are randomly distributed on the upper surface of the reflective film and used for increasing the distance between the reflective film and the light guide plate. The under-screen fingerprint identification apparatus of the present application can relieve or eliminate a thin film interference phenomenon generated by a backlight module, and a fingerprint imaging effect is ensured.

Description

Under-screen fingerprint recognition device, backlight module, liquid crystal display and electronic equipment

Technical field

This application relates to the field of fingerprint identification technology, and in particular to an under-screen fingerprint identification device, a backlight module, a liquid crystal display and electronic equipment.

Background technique

Fingerprint recognition and unlocking has become a basic function that most mobile terminals such as mobile phones and tablet computers are equipped with. With the pursuit of full screens of mobile terminals by users, the application of under-screen fingerprint recognition technology has become more and more widespread, among which under-screen optical fingerprint recognition technology is the most popular. At present, mobile terminals with under-screen optical fingerprint recognition on the market all use Organic Light-Emitting Diode (OLED) displays, but the cost of OLED displays is relatively high, so liquid crystal displays (LCD) are used. The under-screen optical fingerprint recognition technology is gradually advancing towards commercialization.

However, when the various layers of optical films in the backlight module of the LCD display are bonded together, since the thickness of each layer of optical films is thin and flexible, it is easy to deform, so two adjacent layers of film materials are adjacent to each other. There will be an uneven air gap between them, which will cause the optical path difference to occur when the light propagates between the various layers of optical film materials, which meets the conditions for the formation of thin-film interference on the optics, resulting in the phenomenon of thin-film interference, that is, "Newton's ring", this phenomenon It will cause serious interference to the fingerprint imaging effect.

Summary of the invention

This application provides an under-screen fingerprint identification device, a backlight module, a liquid crystal display and electronic equipment, which can alleviate or eliminate the film interference phenomenon generated by the backlight module and ensure the fingerprint imaging effect.

In the first aspect, the present application provides an under-screen fingerprint identification device, which is suitable for electronic equipment with a liquid crystal display, and the fingerprint detection area of the under-screen fingerprint identification device is at least partially located in the display area of the liquid crystal display;

The under-screen fingerprint identification device includes a fingerprint identification module located below the backlight module of the liquid crystal display, and the fingerprint identification module is used to receive the fingerprint identification module formed by the reflection or transmission of the finger above the fingerprint detection area. Pass the fingerprint detection light of the liquid crystal display to obtain the fingerprint image of the finger;

Wherein, the backlight module includes a diffuser film, a light guide plate and a reflective film, the light guide plate is arranged adjacently below the diffuser film, and the surface of the diffuser film facing the light guide plate has a plurality of spaced first A microstructure, the first microstructure is randomly distributed on the lower surface of the diffusion film and used to increase the distance between the diffusion film and the light guide plate, and the reflective film is adjacently arranged on the guide plate Below the light plate, the surface of the reflective film facing the light guide plate has a plurality of second microstructures arranged at intervals, and the second microstructures are randomly distributed on the upper surface of the reflective film and used to increase the reflection The distance between the film and the light guide plate can not only avoid film interference between the diffusion film and the light guide plate, and between the light guide plate and the reflective film, but also can avoid the first micro Moire fringes are formed between the structure or the second microstructure and the light guide groove of the light guide plate, so that the fingerprint imaging effect can be improved, so that the under-screen fingerprint identification device can obtain a clear fingerprint image.

In the second aspect, the present application provides a backlight module suitable for a liquid crystal display that supports under-screen fingerprint recognition. The backlight module includes a diffuser film, a light guide plate, and a reflective film. The light guide plate is adjacently arranged on the diffuser Below the film, the surface of the diffusion film facing the light guide plate has a plurality of first microstructures arranged at intervals, and the first microstructures are randomly distributed on the lower surface of the diffusion film and used to increase the diffusion The distance between the film and the light guide plate, the reflective film is adjacently arranged below the light guide plate, the surface of the reflective film facing the light guide plate has a plurality of second microstructures arranged at intervals, the The second microstructures are randomly distributed on the upper surface of the reflective film and are used to increase the distance between the reflective film and the light guide plate, which can not only prevent the diffusion film and the light guide plate, but also Thin film interference occurs between the light guide plate and the reflective film, which can also prevent the formation of moiré fringes between the first microstructure or the second microstructure and the light guide groove of the light guide plate, and improve the fingerprint imaging effect. In order to make the fingerprint identification device under the screen obtain a clear fingerprint image.

In a third aspect, the present application provides a liquid crystal display that supports an under-screen fingerprint identification function. The under-screen fingerprint identification device described in the first aspect is arranged below the liquid crystal display, and the liquid crystal display includes a liquid crystal module and the second In the backlight module described in the aspect, the backlight module is located under the liquid crystal module, and is used to provide backlight for the liquid crystal module, and transmits the fingerprint detection light formed by the reflection or transmission of the finger above the liquid crystal display to all under the backlight module. Describes the fingerprint recognition device under the screen.

In a fourth aspect, the present application provides an electronic device, which may include the liquid crystal display screen described in the third aspect and the under-screen fingerprint identification device described in the first aspect. The liquid crystal display screen includes a liquid crystal module and the liquid crystal display device described in the second aspect. The backlight module, wherein the backlight module is located below the liquid crystal module.

Description of the drawings

In order to more clearly describe the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are Some examples of this application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.

Figure 1 is a schematic diagram of the structure of an under-screen fingerprint identification device in an electronic device with a display screen;

2 is a schematic diagram of the bonding gap between two layers of optical film materials of the backlight module;

3 is a thin film interference pattern generated between two optical films of the backlight module of FIG. 2;

4 is a schematic structural diagram of a backlight module provided by Embodiment 1 of the application;

Fig. 5 is a bottom view of the diffusion film provided in the first embodiment of the application;

6 is a schematic diagram of the structure of the light guide plate provided in Embodiment 1 of the application;

7a to 7c are schematic diagrams of the liquid crystal module provided in Embodiment 1 of the application;

FIG. 8 is a schematic diagram of another backlight module provided in Embodiment 1 of the application.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments It is a part of the embodiments of the present application, but not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of this application.

The technical solutions of the embodiments of the present application can be applied to various electronic devices.

For example, portable or mobile computing devices such as smartphones, notebook computers, tablet computers, and gaming devices, as well as other electronic devices such as electronic databases, automobiles, and bank automated teller machines (ATM). However, the embodiment of the present application does not limit this.

The technical solutions of the embodiments of the present application can be used in biometric identification technology. Among them, biometric recognition technologies include, but are not limited to, fingerprint recognition, palmprint recognition, iris recognition, face recognition, and living body recognition. For ease of description, the following uses fingerprint recognition technology as an example for description.

The technical solutions of the embodiments of the present application can be used in the under-screen fingerprint identification technology. Under-screen fingerprint recognition technology means that the fingerprint recognition module is installed below the display screen, so that fingerprint recognition operations can be performed in the display area of the display screen, without the need to set a fingerprint collection area on the front of the electronic device except for the display area. Specifically, the fingerprint identification module uses light returned from the top surface of the display assembly of the electronic device to perform fingerprint sensing and other sensing operations. This returned light carries information about objects (for example, fingers) in contact with the top surface of the display assembly, and the fingerprint recognition module located below the display assembly collects and detects this returned light to realize fingerprint recognition under the screen.

Example one

Figure 1 is a schematic diagram of the structure of an under-screen fingerprint identification device in an electronic device with a display screen; Figure 2 is a schematic diagram of the bonding gap between the two layers of optical films of the backlight module; Figure 3 is the backlight module of Figure 2 The film interference pattern generated between the two optical film materials in the group; FIG. 4 is a schematic structural diagram of the backlight module provided in the first embodiment of the application; FIG. 5 is a bottom view of the diffusion film provided in the first embodiment of the application; FIG. 6 Fig. 7a-7c are schematic diagrams of the liquid crystal module provided in the embodiment 1 of this application; Fig. 8 is a schematic diagram of another backlight module provided in the embodiment 1 of this application Schematic. In the embodiments of the present application, in order to simplify the description, the same components may use the same reference numerals.

As shown in FIG. 1, this embodiment provides an under-screen fingerprint identification device 1, which is suitable for electronic equipment with a liquid crystal display 2. The fingerprint detection area of the under-screen fingerprint identification device 1 is at least partially located in the display area of the liquid crystal display 2. . Specifically, the under-screen fingerprint identification device 1 provided in this embodiment can be applied to the liquid crystal display screen 2. The under-screen fingerprint identification device 1 is an under-screen optical fingerprint identification device, which can be applied to smart phones, tablet computers, and other liquid crystal displays. Screen 2 on the mobile terminal or electronic device.

More specifically, in the above-mentioned mobile terminal or electronic device, the under-screen fingerprint identification device 1 may be arranged in a partial area below the liquid crystal display 2 and cooperate with the liquid crystal display 2 to form an under-screen fingerprint identification system. Wherein, the fingerprint detection area of the under-screen fingerprint identification device 1 may be specifically located in at least part of the display area of the liquid crystal display 2. For example, by placing a finger above the corresponding fingerprint detection area in the display area of the liquid crystal display 2, so that the fingerprint identification device 1 under the screen acquires and recognizes the fingerprint image of the finger.

As shown in FIG. 1, the liquid crystal display 2 generally includes a liquid crystal module 21 and a backlight module 22. The backlight module 22 is arranged under the liquid crystal module 21 to provide a backlight source for the liquid crystal module 21 to make the liquid crystal module 21 21 can display images for users to watch. The liquid crystal module 21 also includes a wiring module 24 arranged in the non-display area of the liquid crystal module 21 to realize the electrical connection between the liquid crystal module 21 and the outside world.

Specifically, the under-screen fingerprint identification device 1 may include a fingerprint identification module 11 located below the backlight module 22 of the liquid crystal display 2, and the fingerprint identification module 11 is used to receive the fingerprints formed by the reflection or transmission of the finger above the fingerprint detection area. The fingerprint detection light of the liquid crystal display 2 is transmitted to obtain the fingerprint image of the finger.

As shown in Figure 1, the under-screen fingerprint recognition device 1 includes a fingerprint recognition module 11, the fingerprint recognition module 11 may include a fingerprint sensor 112, the fingerprint sensor 112 may be an optical fingerprint sensor 112, and the fingerprint sensor 112 may include multiple sensing units. The optical sensing array and the reading circuit and other auxiliary circuits electrically connected with the optical sensing array. The sensing area of the optical sensing array may correspond to the fingerprint recognition area of the fingerprint sensor 112.

The fingerprint sensor 112 may be located under the fingerprint detection area of the liquid crystal display 2. For example, the fingerprint sensor 112 is located under the backlight module 22 directly opposite the fingerprint detection area of the liquid crystal display 2. Above the fingerprint detection area, the fingerprint detection light carrying fingerprint information formed by the reflection or transmission of the finger is transmitted to the fingerprint sensor 112 through the backlight module 22, and the fingerprint image is acquired and recognized through the fingerprint recognition area of the fingerprint sensor 112.

In addition, since the fingerprint detection area corresponding to the under-screen fingerprint identification device 1 can be located in the display area of the liquid crystal display 2, the user needs to perform fingerprint unlocking or other fingerprints on the mobile terminal or electronic device using the under-screen fingerprint identification device 1 When verifying, it only needs to press a finger on the fingerprint detection area of the liquid crystal display 2 to realize fingerprint input. Therefore, the display area of the liquid crystal display 2 can be expanded to cover the entire front of the mobile terminal or electronic device, which satisfies Full screen requirements for high screen-to-body ratio.

In a possible implementation, the fingerprint recognition module 11 may further include a light path guiding structure 111, which may be arranged above the fingerprint sensor 112; wherein the light path guiding structure 111 is mainly used to press the finger on the fingerprint detection The fingerprint detection light generated and transmitted through the liquid crystal display 2 is guided to the optical sensing array of the fingerprint sensor 112 for optical detection; the fingerprint identification module 11 may also include a filter layer (not shown in FIG. 1). It can be arranged between the optical path guiding structure 111 and the fingerprint sensor 112, or above the optical path guiding structure 111, to filter out the light signal used to filter out the non-target waveband, and transmit the light signal of the target waveband. The target waveband is It is the wavelength band of the fingerprint detection light to prevent the optical signal of the non-target wavelength band from being received by the optical sensor array and affecting the fingerprint recognition effect. When the filter layer is disposed between the light path guiding structure 111 and the fingerprint sensor 112, optionally, the filter layer may be coated on the optical sensing array of the fingerprint sensor 112 by an evaporation process to be integrated in the fingerprint sensor 112. In the sensor 112, the thickness of the fingerprint identification module is thereby reduced.

Among them, in the under-screen fingerprint identification device 1 provided in this embodiment, the fingerprint sensor 112, the optical path guiding structure 111, and the filter layer may be packaged as one component to form the fingerprint identification module 11.

The light path guiding structure 111 can adopt various implementations. In a possible implementation, the light path guiding structure 111 may be an optical lens layer, which includes one or more lenses, such as a lens group composed of one or more aspheric lenses. The optical lens layer can be used to converge the fingerprint detection light formed by reflection or transmission from the finger and passing through the liquid crystal display 2 to the optical sensor array of the fingerprint sensor 112 below it, so that the optical sensor array can perform processing based on the fingerprint detection light. Optical imaging is used to obtain the fingerprint image of the finger.

Optionally, the optical lens layer may also be formed with a pinhole or aperture stop in the optical path of the one or more lenses, and the pinhole or aperture stop may cooperate with the optical lens layer to expand the under-screen fingerprint identification device 1 Filed of View (FOV) to improve the fingerprint imaging effect of the fingerprint device under the screen.

In another possible implementation manner, the light path guiding structure 111 may specifically be a collimator (Collimator) layer fabricated on a semiconductor silicon wafer or other substrate, which has a plurality of collimator units, and the collimator unit may be specifically Collimation through hole with a certain aspect ratio; when the user performs fingerprint recognition on the liquid crystal display 2, in the fingerprint detection light formed by the finger above the liquid crystal display 2 and transmitted through the liquid crystal display 2, the incident angle is consistent with the collimation The fingerprint detection light with the same extending direction of the unit can pass through the collimation unit and be received by the sensing unit below it, while the fingerprint detection light with an excessively large incident angle is attenuated by multiple reflections inside the collimation unit, so every time One sensor unit can basically only receive the fingerprint detection light directly above it, so that the optical sensor array uses the fingerprint detection light detected by each sensor unit to obtain the fingerprint image of the finger.

In other embodiments, the optical path guiding structure 111 may also specifically include a micro-lens (Micro-Lens) layer and an optical film layer. Other processes are formed above the optical sensing array of the fingerprint sensor 112, and each microlens may correspond to one or more sensing units of the optical sensing array. The optical film layer may be formed between the microlens layer and the optical sensing unit, which may include at least one light blocking layer and formed between the light blocking layer and the microlens layer or between the light blocking layer and the optical sensing array The dielectric layer, passivation layer or buffer layer, etc. The light blocking layer includes a plurality of micro holes, and a specific optical design is adopted to make the micro holes formed between the corresponding micro lens and the sensing unit, thereby limiting the angle of the receiving light path of the sensing unit.

Wherein, the light-blocking layer can block the optical interference between adjacent microlenses, and the microlens converges the received fingerprint light signal into the microhole at a specific vertical or oblique angle and transmits it to the sensor via the microhole. Unit for optical fingerprint imaging.

It is understandable that in practical applications, the liquid crystal display 2 may also include a transparent protective cover 23, such as a glass cover or a sapphire cover, which is specifically located above the liquid crystal module 21 of the liquid crystal display 2 and covers the liquid crystal module. The front of group 21. Therefore, in this embodiment, the so-called finger pressing on the liquid crystal display 2 can actually refer to the transparent protective cover 23 pressed on the liquid crystal module 21 or the protective layer covering the surface of the transparent protective cover 23 (such as Tempered film or other protective film).

In a possible implementation, the under-screen fingerprint identification device 1 may further include a detection light source 12, which is used to emit detection light, and the detection light passes through the liquid crystal display 2 and illuminates the finger above the fingerprint identification area. The reflection or transmission forms the fingerprint detection light carrying fingerprint information.

As shown in Figure 1, in this embodiment, the under-screen fingerprint recognition device 1 includes a fingerprint recognition module 11, and also includes a detection light source 12, which emits detection light, which can be irradiated through the liquid crystal display 2 The finger above the fingerprint detection area, the detection light is irradiated to the finger and reflected or transmitted by the finger to form fingerprint detection light. The formed fingerprint detection light is transmitted through the liquid crystal display 2 to the fingerprint recognition module 11 under the backlight module 22, carrying the fingerprint The fingerprint detection light of the information forms a fingerprint image on the fingerprint sensor 112, and fingerprint recognition is performed by the fingerprint sensor 112.

In order to avoid the mutual influence between the fingerprint detection light and the backlight provided by the backlight module 22, as shown in FIG. 1, in a possible implementation manner, the wavelengths of the detection light and the backlight provided by the backlight module 22 for displaying images may be different. . In practical applications, the backlight module 22 may include a backlight source (not shown in FIG. 1), the backlight source provides a backlight for illuminating the liquid crystal display 2, and the backlight provided by the backlight module 22 makes the liquid crystal display 2Display the screen.

In this embodiment, the detection light emitted by the detection light source 12 of the under-screen fingerprint identification device 1 and the backlight provided by the backlight module 22 have different wavelengths, so that the mutual influence between the detection light and the backlight can be avoided. The emitted backlight can be used to illuminate the screen to ensure the brightness of the liquid crystal display 2; and the detection light emitted by the detection light source 12 is mainly used to illuminate the finger above the fingerprint detection area, so that the finger is directed to the fingerprint recognition module 11 reflects or transmits enough light, so as to ensure that the fingerprint sensor 112 obtains a fingerprint image with better clarity. Optionally, the detection light source 12 can be arranged side by side with the liquid crystal module under the transparent protective cover 23, and located at the edge area under the transparent protective cover 23, in order to prevent the user from seeing the detection provided below through the transparent protective cover 23 For the light source 12, a light-shielding layer 231 can be provided on the transparent protective cover 23 above the detection light source 12. The light-shielding layer can transmit the detection light emitted by the detection light source 12. Optionally, the light-shielding layer 231 can be an ink layer. The layer can transmit infrared light. In a specific embodiment, the detection light may be infrared light, and the backlight provided by the backlight module 22 may be visible light. In this embodiment, the under-screen fingerprint recognition device 1 may use a non-visible light source with a specific wavelength as the fingerprint excitation light source to realize optical fingerprint recognition. For example, the detection light emitted by the detection light source 12 may be infrared light, that is, the detection light source 12 is infrared. The light source, for example, the infrared light source may be an infrared LED light source, an infrared vertical cavity surface emitting laser (Vertical Cavity Surface Emitting Laser, VCSEL for short), or an infrared laser diode (Laser Diode).

The infrared light emitted by the detection light source 12 can be irradiated to the finger above the fingerprint detection area of the liquid crystal display 2 through the liquid crystal module 21 or the transparent protective cover 23, and the infrared light can be emitted on the surface of the finger or transmitted from the surface of the finger to form infrared Fingerprint detection light. The infrared fingerprint detection light carries fingerprint information of the finger, which can pass through the liquid crystal module 21 and the backlight module 22 of the liquid crystal display 2 and be transmitted to the fingerprint recognition module 11 under the backlight module 22. The fingerprint identification module 11 guides the fingerprint detection light to the optical sensor array of the fingerprint sensor 112 through the optical path guiding structure 111. The optical sensor array can receive the fingerprint detection light and further obtain fingerprint information of the finger according to the fingerprint detection light.

The backlight provided by the backlight source in the backlight module 22 can be visible light. The visible light illuminates the liquid crystal display 2 so that the liquid crystal display 2 displays images; in this way, the detection light source 12 of the fingerprint identification device 1 under the screen is infrared light. Different from the visible light of the backlight, in order to avoid the mutual influence between the detection light source 12 and the backlight source, all the visible light emitted by the backlight source is used to illuminate the liquid crystal display screen 2, and the infrared light emitted by the detection light source 12 is all used to illuminate the finger to form Fingerprint detection light.

1, the backlight module 22 sequentially includes a brightness enhancement film 221, a diffusion film 22, a light guide plate 223, a reflective film 224, and a back plate 225 from top to bottom. The back plate includes a through hole 2251 to reflect or transmit through the finger. For the formed fingerprint detection light, the fingerprint identification module 11 can be specifically arranged under the through hole 2251. When the various layers of optical film materials in the backlight module 22 are bonded together, an uneven air gap will be formed between two adjacent layers of film materials, resulting in optical path differences when light propagates between the various layers of optical film materials. Resulting in the phenomenon of film interference. In addition, for the area of the optical film corresponding to the through hole of the back plate 225, since this area is not supported by the back plate 225, plus the gravity of the optical film itself, in the area corresponding to the through hole of the back plate 225, each layer of optical The film materials have different degrees of recession to the through holes of the back plate 225, which will also lead to the formation of uneven air gaps between the various layers of optical film materials, resulting in film interference. See Figure 2 and Figure 3 for details.

Among them, Figure 2 is a schematic diagram of the air gap generated when two adjacent layers of optical film materials are laminated. When the fingerprint detection light reflected or transmitted by the finger above the fingerprint detection area passes through the uneven air gap between the optical films of each layer , There will be a film interference phenomenon between the fingerprint detection light transmitted and reflected by the optical film, which will cause the fingerprint detection light to form a "Newton ring", see Figure 3. This will cause the image received by the fingerprint sensor 112 to include a clear "Newton ring", which will seriously interfere with fingerprint imaging.

In order to enable the fingerprint sensor 112 to obtain a clear fingerprint image, to ensure that the fingerprint sensor 112 can effectively identify the fingerprint image, avoid the phenomenon of thin film interference caused by the fingerprint detection light in the process of passing through the backlight module 22, and avoid the optical film materials. "Newton's ring" is produced. This application changes the structure of the optical film material in the backlight module 22 to change the air gap between the optical film materials and destroy the conditions of film interference, so as to solve the problem of fingerprint detection light passing through the backlight module For the problem of film interference at 22 o'clock, see Figure 4 to Figure 8 for details.

FIG. 4 shows an embodiment of the backlight module of the present application. The backlight module 22 may include a diffuser film 222 and a light guide plate 223 adjacently disposed under the diffuser film 222. The surface of the diffuser film 222 facing the light guide plate 223 has a plurality of The first microstructures 2221 are arranged at intervals. The first microstructures 2221 are randomly distributed on the lower surface of the diffusion film 222, and are used to increase the distance between the diffusion film 222 and the light guide plate 223 to prevent the fingerprint detection light from being transmitted and diffused. A film interference phenomenon occurs between the film 222 and the light guide plate 223.

Since the light guide grooves of the general light guide plate are designed to be arranged regularly and have a fixed arrangement period, for example, the light guide plate 223 in FIG. 4 is provided with a light guide groove 2231. The light guide plate 223 in this embodiment will be described in detail later describe. Compared with the regular arrangement of the first microstructures 2221, the first microstructures 2221 present a random distribution on the lower surface of the diffusion film 222, or when it can be called irregular arrangement or distribution, it can effectively avoid the diffusion film 222. The first microstructure 2221 on the surface and the light guide groove 2231 form moiré fringes, so as to prevent the moiré fringe from affecting fingerprint imaging.

The first microstructures 2221 randomly distributed on the lower surface of the diffusion film 222 can not only solve the problem of film interference between the diffusion film 222 and the light guide plate 223, but also avoid the formation of moiré fringes between the first microstructure 2221 and the light guide groove 2231 , Which can improve the effect of fingerprint imaging and recognition.

The shape and size of the first microstructure 2221 are not limited, and can be set according to actual conditions. As an optional embodiment, the first microstructure 2221 may be a convex structure formed on the lower surface of the diffusion film 222. The height of a microstructure 2221 can range from 1 micrometer to 10 micrometers. Optionally, the size of the first microstructure 2221 in the horizontal direction is less than 10 micrometers, or the width of the first microstructure 2221 in the horizontal direction is less than 10 micrometers. .

5 is a front view of the bottom surface of a diffusion film 222 in the backlight module 22 of FIG. 4, and it can be seen that the first microstructures 2221 are randomly distributed on the bottom surface of the diffusion film.

4, the backlight module 22 may also include a reflective film 224, the reflective film 224 is adjacently arranged below the light guide plate 223, the reflective film 224 is used to reflect all the light emitted by the backlight to the light guide plate 223, so that the light guide plate 223 The light plate 223 emits all light from its front surface, and the front surface of the light guide plate 223 is the surface where the light guide groove 2231 is located. Wherein, the surface of the reflective film 224 facing the light guide plate 223 has a plurality of second microstructures 2241 arranged at intervals. The second microstructures 2241 are randomly distributed on the upper surface of the reflective film 224 and are used to increase the distance between the reflective film 224 and the light guide plate 223. The spacing between. Similar to the first microstructure 2221, the second microstructure 2224 presents a random distribution on the upper surface of the reflective film 224, or when it can be called irregular arrangement or distribution, it can not only solve the problem of thin film between the reflective film 224 and the light guide plate 223 The problem of interference can also prevent the formation of moiré fringes between the second microstructure 2241 and the light guide groove 2231, thereby improving the effect of fingerprint imaging and recognition.

The shape and size of the second microstructure 2241 are not limited, and can be set according to actual conditions. As an optional embodiment, the second microstructure 2241 may be a convex structure formed on the upper surface of the reflective film 224. The height of the second microstructure 2241 can range from 1 micrometer to 10 micrometers. Optionally, the size of the second microstructure 2241 in the horizontal direction is less than 10 micrometers, or the width of the second microstructure 2241 in the horizontal direction is less than 10 micrometers. . Figure 4 also shows the position of the fingerprint identification module 11 of the under-screen fingerprint identification device 1 relative to the backlight module 22. The fingerprint identification module 11 is arranged below the backlight module 22. For the specific fingerprint identification process and principle, please refer to The content of Figure 1 will not be repeated here.

FIG. 6 is a specific embodiment of the light guide plate 223 in FIG. 4. 6, in a possible implementation manner, the light guide plate 223 includes a base material 2232, the upper surface of the base material 2232 is provided with a plurality of raised light guide grooves 2231, the light guide grooves 2231 along the first direction of the light guide plate 223 Extend and are arranged at even intervals along the second direction of the light guide plate 223, and the arrangement period of the light guide grooves 2231 along the second direction is T1.

Optionally, the first direction is parallel to the long side of the light guide plate 223, and the second direction is parallel to the short side of the light guide plate 223, or the first direction is parallel to the short side of the light guide plate 223. The two directions are parallel to the long side of the light guide plate 223.

In this embodiment, the light guide groove 2231 can enhance the light guide function of the light guide plate 223, so that the backlight emitted by the backlight source located on one side of the light guide plate 223 is better transmitted to the other side of the light guide plate 223, so that the light guide plate 223 The surface light source emitted from the front of the light plate 223 has a relatively uniform brightness. In addition, the plurality of light guide grooves 2231 and the first microstructure 2221 of the diffusion film 222 are jointly supported between the diffusion film 222 and the light guide plate 223, which can further increase the distance between the diffusion film 222 and the light guide plate 223, and effectively solve the diffusion problem. The problem of film interference between the film 222 and the light guide plate 223. Optionally, the cross section of the light guide groove 2231 along the second direction may be arcuate. The arcuate light guide groove 2231 has a certain light-gathering function. While enhancing the light guide of the light guide plate 223, the provision of the light guide groove 2231 can also increase the brightness of the light emitted from the light guide plate 223 to enhance the liquid crystal The display effect of the display screen 2. As an optional embodiment, the height of the light guide groove 2231 can range from 1 micron to 3 micrometers. For example, the height of the light guide groove 2231 can be 1.5 micrometers, 1.75 micrometers, 1.8 micrometers, 2 micrometers, 2.5 micrometers, etc. Preferably, the height of the light guide groove 2231 may be 1.75 μm. The radius of curvature of the arc corresponding to the arc can range from 30 microns to 150 microns. For example, the radius of curvature of the arc can be 30 microns, 40 microns, 50 microns or 70 microns, etc., preferably, so The radius of curvature of the arc or light guide groove 2231 may be 40 microns. In this way, the light guide groove 2231 forms a relatively smooth arcuate columnar structure on the surface of the light guide plate 223. The light guide groove 2231 can improve the light guide effect of the light guide plate 223. At the same time, the light guide groove 2231 is in contact with the first microstructure 2221 of the diffusion film 222. When the stability is better.

It should be noted that, as mentioned above, in this embodiment, by arranging the first microstructures 2221 on the lower surface of the diffusion film 222 in a randomly distributed form, the difference between the multiple first microstructures 2221 and the different light guide grooves 2231 is different. The position contact makes the gap between the diffusion film 222 and the light guide plate 223 more uniform overall. The distance between the diffusion film 222 and the light guide plate 223 is jointly determined by the first microstructure 2221 and the light guide groove 2231, which can not only avoid The problem of thin-film interference between the diffusion film 222 and the light guide plate 223 can also avoid the formation of moiré fringes between the first microstructure 2221 and the light guide groove 2231, thereby improving the effect of fingerprint imaging.

It is worth noting that, in general, the liquid crystal module of the liquid crystal display screen includes liquid crystal pixels arranged in an array, and the light guide grooves 2231 can be arranged at even intervals along the second direction, that is, regularly arranged in a certain period. Therefore, if the arrangement period of the light guide groove 2231 is set improperly, moire fringes will be generated between the liquid crystal pixels, which will cause moiré fringes to appear on the liquid crystal display, which will interfere with the display, thereby affecting the display effect and further affecting the fingerprint imaging. Referring to FIGS. 7a-7c and FIG. 1, as shown in FIGS. 1 and 7a-7c, the liquid crystal display 2 may also include a liquid crystal module 21 disposed above the backlight module 22, and the liquid crystal module 21 includes an array The distributed liquid crystal pixels 2111 are used to display images. The liquid crystal pixel 2111 may include a plurality of sub-pixels 2111a. In this embodiment, the liquid crystal pixel 2111 includes three sub-pixels 2111a. Optionally, the three sub-pixels 2111a may be sub-pixels of different colors. For example, the three sub-pixels 2111a are red sub-pixels. , Green sub-pixel and blue sub-pixel.

As an optional embodiment, the shapes and sizes of the three sub-pixels 2111a in the liquid crystal pixel 2111 are all the same, as shown in FIG. The arrangement period of the second direction of the group 21 is T2. It can be understood that the second direction of the light guide plate 223 is the same as the second direction of the liquid crystal module 211. The cloth cycle is marked with respect to the liquid crystal module 21. The arrangement period of the light guide groove 2231 in the second direction is T1, and T1>T2, that is, the arrangement period T1 of the light guide groove 2231 in the second direction is greater than the arrangement period of the sub-pixel 2111a in the second direction, so as to avoid the light guide groove 2231 The arrangement period overlaps with the sub-pixel 2111a to generate moiré fringes, which affects the display effect of the liquid crystal display 2 and further affects the effect of fingerprint imaging and recognition. Optionally, T1-T2≥60 microns. At this time, there is almost no moiré between the light guide groove 2231 and the sub-pixel 2111a, and the display effect of the liquid crystal display 2 will not be affected.

As another optional embodiment, the shapes and sizes of the three sub-pixels 2111a in the liquid crystal pixel 2111 may be different. Optionally, the shapes or sizes of at least two of the three sub-pixels 2111a are different. For example, the shapes of the three sub-pixels 2111a are different, or the sizes of the three sub-pixels 2111a are different; for another example, among the three sub-pixels 2111a, two of the sub-pixels have different shapes, or two of the sub-pixels have different sizes. . As shown in Figure 7b, among the three sub-pixels 2111a, two sub-pixels 2111a have different shapes. One of the sub-pixels 2111a has a rectangular shape, the other two sub-pixels 2111a have a trapezoidal shape, and the rectangular sub-pixel 2111a is located in the shape of The middle of the two trapezoidal sub-pixels 2111a. The shape and size of the sub-pixel 2111a in FIGS. 7a and 7b are only illustrative. Optionally, the shape of the sub-pixel 2111a may also be other shapes, which are not limited in this embodiment and can be set according to actual requirements. When at least two sub-pixels 2111a in the liquid crystal pixel 2111 have different shapes or sizes, the arrangement period of the liquid crystal pixels 2111 along the second direction of the liquid crystal module 21 is T3. It can be understood that the second direction of the light guide plate 223 and the liquid crystal mold The second direction of the group 211 is the same. The arrangement period of the light guide groove 2231 in the second direction is T1, and T1>T3, that is, the arrangement period T1 of the light guide groove 2231 in the second direction is greater than the arrangement period of the liquid crystal pixels 2111 in the second direction, so as to avoid the light guide groove 2231 The arrangement period overlaps with the liquid crystal pixel 2111 to produce moiré fringes, which affects the display effect of the liquid crystal display 2 and further affects the effect of fingerprint imaging and recognition. Optionally, T1-T3≥60 microns. At this time, there is almost no moiré fringe generated between the light guide groove 2231 and the liquid crystal pixel 2111, and the display effect of the liquid crystal display 2 will not be affected. It can be understood that the size difference of the three sub-pixels 2111a with different colors in the liquid crystal pixel 2111 cannot be too large, otherwise display problems will occur.

Continuing to refer to FIG. 6, in a possible embodiment, the lower surface of the light guide plate 223 includes a plurality of light guide particles 2233 spaced apart. Specifically, the bottom surface of the substrate 2232 is provided with a plurality of light guide particles spaced apart. 2233. When the light emitted by the backlight hits the light guide particles 2233, the light guide particles 2233 will diffuse the reflected light to various angles, and then destroy the reflection conditions. The light guide plate 223 is emitted from the front side, that is, the light guide groove 2231 is located. . The light guide particles 2233 at different positions can make the light guide plate 223 emit light uniformly.

4 and 6 together, the light guide particles 2233 are supported between the light guide plate 223 and the reflective film 224, which can further increase the distance between the light guide plate 223 and the reflective film 224, by setting a reasonable size for the light guide particles 2233 The size, the gap between the light guide plate 223 and the reflective film 224 can be controlled within a reasonable range, so as to eliminate the film interference phenomenon between the light guide plate 223 and the reflective film 224. The embodiment of the present application does not limit the size of the light guide particles 2233, and can be set according to actual conditions. As an optional embodiment, the height of the light guide particles 2233 can range from 3 microns to 5 microns, for example The height of the light guide particles 2233 can be 3 microns, 3.5 microns, 4 microns, 4.5 microns or 5 microns. Preferably, the height of the light guide particles 2233 can be 4 microns. At this time, not only can the light guide function be achieved, but also The film interference phenomenon between the light guide plate 223 and the reflective film 224 is avoided, and the effect of fingerprint imaging is improved. At the same time, the backlight module 22 will not become too thick, which will ultimately affect the experience of the end user. It is understandable that the light guide groove 2231 and the light guide particles 2233 can be made of the same material as the substrate 2232, and the light guide groove 2231 and the light guide particles 2233 can be formed on the two surfaces of the substrate 2232 by etching or the like, so that the guide The light groove 2231, the base material 2232 and the light guide particles 2233 are integrally formed.

In a specific embodiment, the density of the light guide particles 2233 in different regions on the lower surface of the light guide plate 223 may be different. In this embodiment, the light guide particles 2233 may be distributed on the lower surface of the light guide plate 223 in a non-uniform manner. Among them, since the backlight of the backlight module 22 is arranged on one side of the light guide plate 223, the light guide plate 223 The light in the part closer to the backlight is stronger, and the light in the part farther from the backlight is weaker. Therefore, the density of the light guide particles 2233 in the area closer to the backlight on the light guide plate 223 can be less than that of the backlight. The density of the light guide particles 2233 in the remote area is such that by disposing light guide particles 2233 of different densities in unused areas, each area of the light guide plate 223 has a relatively uniform light intensity.

Referring to FIG. 8, in a possible embodiment, the backlight module 22 may further include a brightness enhancement film 221 disposed adjacently above the diffusion film 222, and the surface of the brightness enhancement film 221 facing the diffusion film 222 has a plurality of spaced apart The third microstructures 2211 are randomly distributed on the lower surface of the brightness enhancement film 221 and are used to increase the distance between the brightness enhancement film 221 and the diffusion film 222. The brightness enhancement film 221 is used to enhance the brightness of light. The light is homogenized by the diffusion film 222 and then directed to the brightness enhancement film 221. The brightness enhancement film 221 can further increase the brightness of the light to improve the brightness of the liquid crystal display 2.

The third microstructure 2211 is supported between the brightness enhancement film 221 and the diffusion film 222 to increase the gap between the brightness enhancement film 221 and the diffusion film 222 to prevent fingerprint detection light from passing between the brightness enhancement film 221 and the diffusion film 222 Film interference phenomenon occurs. Not only that, the third microstructure 2211 presents a random distribution on the lower surface of the brightness enhancement film 221, or when it can be called irregular arrangement or distribution, it can also avoid the third microstructure 2211 and the light guide groove 2231. Moiré fringes are formed between them, which can enhance the fingerprint imaging effect. Specifically, the third microstructure 2211 may be a microsphere structure embedded in the lower surface of the brightness enhancement film 221, and the diameter of the third microstructure 2211 ranges from 4 microns to 10 microns. By configuring the third microstructure 2211 as a microsphere structure, the brightness of the light can be further enhanced, and the brightness of the liquid crystal display screen 2 can be improved. On the basis that the third microstructure 2211 is partially embedded in the lower surface of the brightness enhancement film 221, the height of the third microstructure 2211 exposed on the lower surface of the brightness enhancement film 221 can still ensure that there will be no generation between the brightness enhancement film 221 and the diffusion film 222. Film interference phenomenon. Exemplarily, the diameter of the third microstructure 2211 may be 4 micrometers, 5 micrometers, 6 micrometers, 7 micrometers or 8 micrometers, etc. Preferably, the diameter of the third microstructure 2211 may be 5 micrometers.

Continuing to refer to FIG. 8, the upper surface of the brightness enhancement film 221 may have a plurality of fourth microstructures 2212 arranged at intervals, and the fourth microstructures 2212 are randomly distributed on the upper surface of the brightness enhancement film 221. 1 together, the liquid crystal display 2 may also include a liquid crystal module 21 located above the backlight module 22, and the brightness enhancement film 221 is located on the uppermost layer of the backlight module 22, so the fourth microstructure 2212 is supported on the brightness enhancement film 221 And the liquid crystal module 21 to increase the distance between the brightness enhancement film 221 and the liquid crystal module 21 to avoid the phenomenon of thin film interference when the fingerprint detection light passes between the brightness enhancement film 221 and the liquid crystal module 21, not only that, When the fourth microstructure 2212 presents a random distribution on the upper surface of the brightness enhancement film 221, or can be called irregular arrangement or distribution, it can also avoid the formation of moire fringes between the fourth microstructure 2212 and the light guide groove 2231, and thus can Improve fingerprint imaging effect. Specifically, the fourth microstructure 2212 may be a microsphere structure embedded in the upper surface of the brightness enhancement film 221, and the diameter of the fourth microstructure 2212 ranges from 4 microns to 20 microns. On the basis that a part of the fourth microstructure 2212 is embedded in the upper surface of the brightness enhancement film 221, the height of the fourth microstructure 2212 exposed on the upper surface of the brightness enhancement film 221 can still ensure that there is no gap between the brightness enhancement film 221 and the liquid crystal module 21. Produce film interference phenomenon. Exemplarily, the diameter of the fourth microstructure 2212 may be 4 micrometers, 5 micrometers, 6 micrometers, 7 micrometers, 8 micrometers, 9 micrometers, 10 micrometers, 11 micrometers, 12 micrometers, or 13 micrometers, etc., preferably, the fourth micrometer The diameter of structure 2212 may be 10 microns.

Example two

On the basis of the first embodiment above, the under-screen fingerprint identification device provided in this embodiment is suitable for electronic equipment with a liquid crystal display, and the fingerprint detection area of the under-screen fingerprint identification device is at least partially located in the display area of the liquid crystal display; The lower fingerprint recognition device includes a fingerprint recognition module. The fingerprint recognition module is located under the backlight module of the liquid crystal display. The fingerprint detection light reflected or transmitted by the finger above the fingerprint detection area is transmitted to the fingerprint sensor through the liquid crystal display. , Receive and recognize fingerprint images through the fingerprint sensor. Wherein, the backlight module includes a laminated diffusion film and a light guide plate, the light guide plate is located under the diffusion film, by arranging a plurality of first microstructures distributed at intervals on the surface of the diffusion film facing the light guide plate. The microstructure is supported between the diffuser film and the light guide plate, which can increase the distance between the diffuser film and the light guide plate, thereby increasing the air gap between the diffuser film and the light guide plate, and make the air gap of each part more Even, it can avoid the film interference phenomenon when the fingerprint detection light passes through the diffusion film and the light guide plate, and can eliminate the interference of the "Newton ring" caused by the film interference phenomenon on the fingerprint imaging, and ensure the fingerprint imaging effect to make the fingerprint The sensor obtains a clear fingerprint image.

Example three

On the basis of the first embodiment above, this embodiment provides a liquid crystal display screen 2 that supports an under-screen fingerprint recognition function. The under-screen fingerprint recognition device 1 described in the first embodiment is arranged under the liquid crystal display screen 2, and the liquid crystal display The display screen 2 includes a liquid crystal module 21 and a backlight module 22. The backlight module 22 is located under the liquid crystal module 21 and is used to provide backlight for the liquid crystal module 21 and transmit the fingerprint detection light formed by the finger above the liquid crystal display 2 To the fingerprint sensor 112 under the backlight module 22.

The under-screen fingerprint recognition device 1 includes a detection light source 12 and a fingerprint recognition module 11. The detection light source 12 is used to emit detection light to the finger above the fingerprint detection area. The detection light illuminates the finger above the fingerprint detection area and is reflected by the finger. The fingerprint detection light carrying fingerprint information is formed after transmission or transmission, and the fingerprint identification module 11 is used to receive the fingerprint detection light carrying the fingerprint information through the liquid crystal display 2 to obtain the fingerprint image of the finger.

In this embodiment, reference may be made to the description of the backlight module 22 in the first embodiment. In this embodiment, the backlight module 22 will not be further described.

An under-screen fingerprint identification device is provided under the liquid crystal display provided in this embodiment, and the liquid crystal display includes a display module and a backlight module located under the display module. Wherein, the backlight module includes a laminated diffusion film and a light guide plate, the light guide plate is located under the diffusion film, by arranging a plurality of first microstructures distributed at intervals on the surface of the diffusion film facing the light guide plate. The microstructure is supported between the diffusion film and the light guide plate. The first microstructure can increase the distance between the diffusion film and the light guide plate, thereby increasing the air gap between the diffusion film and the light guide plate, and make the The air gap is more uniform, which can avoid the film interference phenomenon when the fingerprint detection light passes through the diffusion film and the light guide plate, and can eliminate the interference of the interference light generated by the film interference phenomenon on the fingerprint imaging, and ensure the fingerprint imaging effect. Make the fingerprint sensor get a clear fingerprint image.

Example four

The embodiment of the present application also provides an electronic device, which may include the liquid crystal display 2 in the third embodiment and the under-screen fingerprint identification device in the second embodiment, wherein the liquid crystal display 2 may include the backlight module 22 in the first embodiment And the liquid crystal module 21, in which the backlight module 22 is located below the liquid crystal module 21, which will not be repeated here.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the application, not to limit them; although the application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or equivalently replace some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the embodiments of the present application. Scope.

Claims

An under-screen fingerprint identification device suitable for electronic equipment with a liquid crystal display screen, characterized in that the fingerprint detection area of the under-screen fingerprint identification device is at least partially located in the display area of the liquid crystal display screen;

The under-screen fingerprint identification device includes a fingerprint identification module located below the backlight module of the liquid crystal display, and the fingerprint identification module is used to receive the fingerprint identification module formed by the reflection or transmission of the finger above the fingerprint detection area. Pass the fingerprint detection light of the liquid crystal display to obtain the fingerprint image of the finger;

Wherein, the backlight module includes a diffuser film, a light guide plate and a reflective film, the light guide plate is arranged adjacently below the diffuser film, and the surface of the diffuser film facing the light guide plate has a plurality of spaced first A microstructure, the first microstructure is randomly distributed on the lower surface of the diffusion film and used to increase the distance between the diffusion film and the light guide plate, and the reflective film is adjacently arranged on the guide plate Below the light plate, the surface of the reflective film facing the light guide plate has a plurality of second microstructures arranged at intervals, and the second microstructures are randomly distributed on the upper surface of the reflective film and used to increase the reflection The distance between the film and the light guide plate.
The under-screen fingerprint identification device according to claim 1, wherein the first microstructure is a convex structure formed on the lower surface of the diffusion film, and the height of the first microstructure ranges from 1 micron to Between 10 microns.
The under-screen fingerprint identification device according to claim 1 or 2, wherein the second microstructure is a convex structure formed on the upper surface of the reflective film, and the height range of the second microstructure is 1 Between microns and 10 microns.
The under-screen fingerprint identification device according to any one of claims 1 to 3, wherein the light guide plate comprises a base material, and the upper surface of the base material is provided with a plurality of convex light guide grooves, so The light guide grooves extend along the first direction of the light guide plate and are arranged at even intervals along the second direction of the light guide plate, and the arrangement period of the light guide grooves along the second direction is T1.
The under-screen fingerprint identification device according to claim 4, wherein the first direction is parallel to the long side of the light guide plate, and the second direction is parallel to the short side of the light guide plate;

Alternatively, the first direction is parallel to the short side of the light guide plate, and the second direction is parallel to the long side of the light guide plate.
The under-screen fingerprint identification device according to claim 4 or 5, wherein the height of the light guide groove ranges from 1 micrometer to 3 micrometers.
The under-screen fingerprint identification device according to claim 6, wherein the height of the light guide groove is 1.75 micrometers.
The under-screen fingerprint identification device according to any one of claims 4-7, wherein the cross section of the light guide groove along the second direction is arcuate, and the curvature radius of the arc corresponding to the arcuate The range is between 30 microns and 150 microns.
The under-screen fingerprint identification device according to claim 8, wherein the radius of curvature of the arc is 40 microns.
The under-screen fingerprint identification device according to any one of claims 4-9, wherein the liquid crystal display further comprises a liquid crystal module located above the backlight module, and the liquid crystal module includes An array of liquid crystal pixels, the liquid crystal pixel includes three sub-pixels with the same shape and size, and the arrangement period of the sub-pixels along the second direction is T2, and T1>T2.
The under-screen fingerprint identification device according to claim 10, wherein T1-T2 is greater than or equal to 60 microns.
The under-screen fingerprint identification device according to any one of claims 4-9, wherein the liquid crystal display further comprises a liquid crystal module located above the backlight module, and the liquid crystal module includes An array of liquid crystal pixels, the liquid crystal pixel includes three sub-pixels, wherein at least two of the three sub-pixels have different shapes or sizes, the arrangement period of the liquid crystal pixels along the second direction is T3, and T1 >T3.
The under-screen fingerprint identification device according to claim 12, wherein T1-T3 is greater than or equal to 60 microns.
The under-screen fingerprint identification device according to claim 12 or 13, wherein one of the three sub-pixels has a rectangular shape, the other two sub-pixels have a trapezoidal shape, and the shape of the three sub-pixels is a rectangle. One sub-pixel is located in the middle of the two sub-pixels with a trapezoidal shape.
The under-screen fingerprint identification device according to any one of claims 4-14, wherein the lower surface of the substrate is provided with a plurality of light guide particles distributed at intervals, and the height of the light guide particles is in the range of Between 3 micrometers and 5 micrometers, the light guide groove, the substrate and the light guide particles are integrally formed.
The under-screen fingerprint identification device according to any one of claims 1-15, wherein the backlight module further comprises a brightness enhancement film arranged adjacently above the diffusion film, and the brightness enhancement film faces The surface of the diffusion film has a plurality of third microstructures arranged at intervals, and the third microstructures are randomly distributed on the lower surface of the brightness enhancement film for increasing the brightness enhancement film and the diffusion film The spacing between.
The under-screen fingerprint identification device according to claim 16, wherein the upper surface of the brightness enhancement film has a plurality of fourth microstructures arranged at intervals, and the fourth microstructures are on the upper surface of the brightness enhancement film. The surface is randomly distributed.
The under-screen fingerprint identification device according to claim 17, wherein the third microstructure is a microsphere structure formed on the lower surface of the brightness enhancement film, and the diameter of the third microstructure is in the range of 4 micrometers. Between 10 microns;

The fourth microstructure is a microsphere structure formed on the upper surface of the brightness enhancement film, and the diameter of the fourth microstructure ranges from 4 micrometers to 20 micrometers.
The under-screen fingerprint identification device according to claim 17 or 18, wherein the liquid crystal display further comprises a liquid crystal module located above the backlight module, and the fourth microstructure is used to enlarge the The distance between the brightness enhancement film and the liquid crystal module.
The under-screen fingerprint identification device according to any one of claims 1-19, further comprising a detection light source, the detection light source is used to emit detection light, and the detection light is irradiated through the liquid crystal display A finger above the fingerprint identification area is reflected or transmitted by the finger to form the fingerprint detection light carrying fingerprint information.
The under-screen fingerprint identification device according to claim 20, wherein the wavelength of the detection light is different from that of the backlight provided by the backlight module for displaying images, the detection light is infrared light, and the backlight The backlight provided by the module is visible light.
A backlight module is suitable for a liquid crystal display screen that supports fingerprint recognition under the screen, and is characterized in that it comprises a diffuser film, a light guide plate and a reflective film. The surface of the diffusion film facing the light guide plate has a plurality of first microstructures arranged at intervals, and the first microstructures are randomly distributed on the lower surface of the diffusion film and are used to enlarge the diffusion film and the light guide plate The reflective film is adjacently arranged below the light guide plate, and the surface of the reflective film facing the light guide plate has a plurality of second microstructures arranged at intervals. The upper surface of the reflective film is randomly distributed, and is used to increase the distance between the reflective film and the light guide plate.
The backlight module according to claim 22, wherein the first microstructure is a convex structure formed on the lower surface of the diffusion film, and the height of the first microstructure ranges from 1 micrometer to 10 micrometers. between.
The backlight module according to claim 22 or 23, wherein the second microstructure is a convex structure formed on the upper surface of the reflective film, and the height of the second microstructure ranges from 1 micron to Between 10 microns.
The backlight module according to any one of claims 22-24, wherein the light guide plate comprises a substrate, the upper surface of the substrate is provided with a plurality of convex light guide grooves, the guide The light grooves extend along the first direction of the light guide plate and are arranged at even intervals along the second direction of the light guide plate, and the arrangement period of the light guide grooves along the second direction is T1.
The backlight module of claim 25, wherein the first direction is parallel to the long side of the light guide plate, and the second direction is parallel to the short side of the light guide plate;

Alternatively, the first direction is parallel to the short side of the light guide plate, and the second direction is parallel to the long side of the light guide plate.
The backlight module of claim 25 or 26, wherein the height of the light guide groove ranges from 1 micrometer to 3 micrometers.
28. The backlight module of claim 27, wherein the height of the light guide groove is 1.75 micrometers.
The backlight module according to any one of claims 25-28, wherein the cross-section of the plurality of light guide grooves along the second direction is arcuate, and the arcuate shape corresponds to the range of the radius of curvature of the arc Between 30 microns and 150 microns.
The backlight module of claim 29, wherein the radius of curvature of the arc is 40 microns.
The backlight module according to any one of claims 25-30, wherein the liquid crystal display screen further comprises a liquid crystal module located above the backlight module, and the liquid crystal module includes an array distributed The liquid crystal pixel includes three sub-pixels with the same shape and size, and the arrangement period of the sub-pixels along the second direction is T2, and T1>T2.
The backlight module of claim 31, wherein T1-T2≥60 microns.
The backlight module according to any one of claims 25-30, wherein the liquid crystal display screen further comprises a liquid crystal module located above the backlight module, and the liquid crystal module includes an array distributed The liquid crystal pixel includes three sub-pixels, wherein at least two of the three sub-pixels have different shapes or sizes, and the arrangement period of the liquid crystal pixels along the second direction is T3, and T1>T3 .
The backlight module of claim 33, wherein T1-T3≥60 microns.
The backlight module according to claim 33 or 34, wherein the shape of one sub-pixel of the three sub-pixels is a rectangle, the shape of the other two sub-pixels is a trapezoid, and the shape of the one sub-pixel is a rectangle. The pixel is located in the middle of the two sub-pixels that are trapezoidal in shape.
The backlight module according to any one of claims 25-35, wherein the lower surface of the substrate is provided with a plurality of light guide particles distributed at intervals, and the height of the light guide particles is in the range of 3 microns. Between 5 microns and 5 microns, the light guide groove, the substrate and the light guide particles are integrally formed.
The backlight module according to any one of claims 22-36, wherein the backlight module further comprises a brightness enhancement film adjacently arranged above the diffusion film, and the brightness enhancement film faces the The surface of the diffusion film has a plurality of third microstructures arranged at intervals, and the third microstructures are randomly distributed on the lower surface of the brightness enhancement film to increase the gap between the brightness enhancement film and the diffusion film. Pitch.
The backlight module of claim 37, wherein the upper surface of the brightness enhancement film has a plurality of fourth microstructures arranged at intervals, and the fourth microstructures are randomly arranged on the upper surface of the brightness enhancement film. distributed.
The backlight module of claim 38, wherein the third microstructure is a microsphere structure formed on the lower surface of the brightness enhancement film, and the diameter of the third microstructure ranges from 4 microns to 10 microns. Between micrometers

The fourth microstructure is a microsphere structure formed on the upper surface of the brightness enhancement film, and the diameter of the fourth microstructure ranges from 4 micrometers to 20 micrometers.
The backlight module according to claim 38 or 39, wherein the liquid crystal display further comprises a liquid crystal module located above the backlight module, and the fourth microstructure is used to increase the brightness The distance between the film and the liquid crystal module.
A liquid crystal display supporting an under-screen fingerprint identification function, characterized in that the under-screen fingerprint identification device according to any one of claims 1-21 is arranged below the liquid crystal display, and the liquid crystal display comprises The liquid crystal module and the backlight module of any one of claims 22-40, the backlight module is located under the liquid crystal module, used to provide a backlight for the liquid crystal module, and display the liquid crystal The fingerprint detection light formed by the reflection or transmission of the finger above the screen is transmitted to the under-screen fingerprint identification device below the backlight module.
An electronic device, characterized by comprising a liquid crystal display and the under-screen fingerprint identification device according to any one of claims 1-21, the liquid crystal display comprising a liquid crystal module and any one of claims 22-40 The backlight module of item 1, wherein the backlight module is located below the liquid crystal module.