WO2021097720A1

WO2021097720A1 - Under-screen fingerprint identification device and terminal apparatus

Info

Publication number: WO2021097720A1
Application number: PCT/CN2019/119773
Authority: WO
Inventors: 青小刚; 李家成; 李顺展
Original assignee: 深圳市汇顶科技股份有限公司
Priority date: 2019-11-20
Filing date: 2019-11-20
Publication date: 2021-05-27
Also published as: CN111095289B; CN111095289A

Abstract

Embodiments of the present application provide an under-screen fingerprint identification device and a terminal apparatus. The under-screen fingerprint identification device is suitable for a terminal apparatus having a liquid crystal display screen, and comprises a fingerprint sensor. The fingerprint sensor is disposed below the backlight module of the liquid crystal display screen to implement under-screen fingerprint detection; the fingerprint sensor comprises an optical sensing array having a plurality of optical sensing units, the optical sensing array being used for receiving fingerprint detection light formed by detection light emitted by a fingerprint detection light source irradiating a finger on the liquid crystal display screen to obtain a fingerprint image of the finger, wherein the fingerprint detection light is transmitted to the fingerprint sensor after passing through the liquid crystal module and backlight module of the liquid crystal display screen, and the backlight module comprises a brightness enhancement film, a light homogenization film, and anti-adsorption particles, wherein the anti-adsorption particles are located between the brightness enhancement film and the light homogenization film.

Description

Fingerprint identification device under the screen and terminal equipment

Technical field

This application relates to the field of fingerprint identification technology, and in particular to an under-screen fingerprint identification device and terminal equipment suitable for liquid crystal display screens.

Background technique

In the prior art, the under-screen fingerprint recognition technology of organic light emitting display screens is widely used. The under-screen fingerprint recognition technology of the liquid crystal display is developing. Among them, the liquid crystal display includes the use of a backlight module to provide a backlight for the liquid crystal panel above it so that the liquid crystal panel displays images. The backlight module generally includes a uniform light film and a brightness enhancement film, which are stacked and cooperated to make the backlight output by the backlight module uniform and with sufficient brightness. However, when the user presses the liquid crystal display with his finger to achieve fingerprint input, the uniform light film and brightness enhancement film of the backlight module may be deformed by the user’s finger pressing and the contact may appear uneven, and then the liquid crystal display The under-screen fingerprint identification device at the bottom of the screen produces interference stripes, which interferes with the under-screen fingerprint identification technology.

Application content

In order to solve the above technical problems, embodiments of the present application provide an under-screen fingerprint identification device and terminal equipment.

In the first aspect, the present application provides an under-screen fingerprint identification device, which is suitable for terminal equipment with a liquid crystal display. The under-screen fingerprint identification device includes a fingerprint sensor, and the fingerprint sensor is used to install on the liquid crystal display. Below the backlight module to achieve under-screen fingerprint detection; the fingerprint sensor includes an optical sensor array with a plurality of optical sensor units, the optical sensor array is used to receive the detection light emitted by the fingerprint detection light source and irradiate above the liquid crystal display The fingerprint detection light formed by the finger of the finger to obtain the fingerprint image of the finger; wherein the fingerprint detection light is transmitted to the fingerprint sensor after passing through the liquid crystal module and the backlight module of the liquid crystal display. The backlight module includes a brightness enhancement film, a uniform light film, and anti-adsorption particles, wherein the anti-adsorption particles are located between the brightness enhancement film and the uniform light film.

In an implementation of the first aspect, the anti-adsorption particles are light-transmitting anti-adsorption particles formed by using a light-transmitting material, and are used to isolate the brightness enhancement film and the light homogenizing film to prevent the two from each other. Adsorption.

In an implementation of the first aspect, there is a predetermined anti-absorption distance between the homogenizing film and the brightness enhancement film, and the ratio of the anti-absorption distance to the emission wavelength of the fingerprint detection light source is greater than two. one.

In an implementation of the first aspect, the anti-adsorption particles are formed on the lower surface of the brightness enhancement film or formed on the upper surface of the uniformity film, and the brightness enhancement film and the uniformity film The anti-adsorption distance between them is formed by the anti-adsorption particles.

In an implementation of the first aspect, the fingerprint detection light source is an infrared supplement light lamp, and the infrared supplement light lamp is used to emit infrared light of a specific wavelength to a finger above the liquid crystal display screen, and the infrared light As the detection light, the fingerprint detection light is formed on the finger.

In an implementation of the first aspect, the brightness enhancement film includes a main body and a microprism structure formed on the upper surface of the main body, and the microprism structure is used for the visible light provided by the backlight module in the The brightness in the vertical direction of the brightness enhancement film; the anti-adsorption particles are formed on the lower surface of the main body of the brightness enhancement film.

In an implementation of the first aspect, the brightness enhancement film includes multiple layers of organic film materials with different refractive indexes and adopting a non-prism structure, which are used to enable backlighting through the multiple layers of organic film materials with different refractive indexes. The visible light provided by the module is constrained in the vertical direction of the brightness enhancement film to increase the brightness of the visible light output by the backlight module.

In an implementation of the first aspect, the upper surface of the brightness enhancement film close to the liquid crystal module and the lower surface of the brightness enhancement film close to the homogenization film are both smooth surfaces, and the brightness enhancement film and the Anti-adsorption particles are also formed between the liquid crystal modules.

In an implementation of the first aspect, the ratio of the distance between the brightness enhancement film and the liquid crystal module to the emission wavelength of the fingerprint detection light source is greater than one-half.

In an implementation of the first aspect, haze particles are also formed between the light homogenizing film and the brightness enhancement film, and the haze particles are used to homogenize the visible light provided by the backlight module. Light fogging treatment, and the fingerprint detection light can penetrate the haze particles.

In an implementation of the first aspect, the haze particles are used to cooperate with the anti-adsorption particles to further prevent mutual adsorption between the brightness enhancement film and the uniformity film.

In an implementation of the first aspect, the haze particles are formed on the upper surface of the homogenizing film, and the anti-adsorption particles are formed on the lower surface of the brightness enhancement film, and there is gap.

In an implementation of the first aspect, anti-adsorption particles and haze particles are formed between the brightness enhancement film and the liquid crystal module at the same time, and the anti-adsorption particles and the haze particles cooperate with each other to prevent There is mutual adsorption between the brightness enhancement film and the liquid crystal module.

In an implementation of the first aspect, the anti-adsorption particles and the haze particles between the brightness enhancement film and the liquid crystal module are respectively formed by forming an anti-adsorption particle layer and fog on the upper surface of the brightness enhancement film. A high-degree particle layer is implemented, wherein the haze particle layer can coat the anti-adsorption particles on the upper surface of the brightness enhancement film.

In an implementation of the first aspect, the anti-adsorption particles and haze particles between the brightness enhancement film and the liquid crystal module are realized by forming a composite particle layer on the upper surface of the brightness enhancement film, so The composite particle layer includes the anti-adsorption particles and the haze particles.

In an implementation of the first aspect, a glass cover is covered above the liquid crystal module, the glass cover has an edge extension relative to the liquid crystal module, and the fingerprint detection light source is disposed on the Below the edge extension part, and emit the detection light to the finger above the liquid crystal display at a predetermined inclination angle.

In an implementation of the first aspect, the fingerprint sensor further includes a light path guide structure formed above the optical sensing array, and the light path guide structure is used to guide the fingerprint detection light passing through the liquid crystal display to the述optical sensing array.

In an implementation manner of the first aspect, the optical path guiding structure includes a macro lens with a plurality of aspheric lenses and a lens barrel or lens holder for carrying the macro lens, and the lens barrel or lens holder is arranged at Above the flexible circuit board and forming a confined space with the flexible circuit board, the optical sensing array is arranged in the confined space and located in the converging light path of the macro lens; wherein, the macro lens is used to pass all The multiple aspherical lenses cooperate with the micro-aperture diaphragm between the lenses to realize macro imaging with an increased effective field of view, so as to converge the fingerprint detection light passing through the liquid crystal display to the optical sensor array And realize the optical fingerprint imaging of the finger on the optical sensor array.

In an implementation of the first aspect, the optical path guiding structure includes an optical path guiding layer formed above the optical sensor array by a semiconductor process, and the optical path guiding layer includes a microlens array and is located between the microlens array and the optical sensor. Multiple light-blocking layers between the arrays, the multiple light-blocking layers respectively define multiple transmission light paths between the microlens array and the optical sensor array through openings, wherein each microlens of the microlens array is used The fingerprint detection light is respectively focused to its corresponding transmission optical path, and transmitted to the corresponding optical sensing unit through the transmission optical path.

In an implementation manner of the first aspect, the optical sensor further includes a filter, and the filter is formed on the optical sensing array or the optical path guiding structure by coating, and is used to filter out the entry into the optical sensing Interfering light from the array.

In the second aspect, the present application provides a terminal device, including a liquid crystal display screen with a liquid crystal module and a backlight module, and an under-screen optical fingerprint identification device arranged under the liquid crystal display, wherein the under-screen optical fingerprint identification The device is the above-mentioned under-screen optical fingerprint device.

In the embodiment of the present application, the fingerprint sensor receives the fingerprint detection light formed by the finger above the liquid crystal display, and the fingerprint detection light passes through the backlight module and is transmitted to the fingerprint sensor, wherein the brightness enhancement film and uniformity of the backlight module are transmitted to the fingerprint sensor. Anti-adsorption particles are formed between the light films, and the anti-adsorption particles can be physically separated between the brightness enhancement film and the homogenizing film or form an anti-adsorption distance between the two to prevent the two from appearing when the fingerprint is pressed by the finger. The deformation sometimes causes mutual adsorption, so as to prevent the fingerprint detection light from passing through the homogenizing film and the brightness enhancing film to produce interference fringes, and effectively improve the fingerprint recognition performance of the fingerprint recognition device under the screen.

Description of the drawings

In order to explain the technical solutions of the embodiments of the present invention more clearly, the following will briefly introduce the drawings needed in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative work, other drawings can be obtained from these drawings.

FIG. 1 is a schematic structural diagram of an under-screen fingerprint identification device suitable for liquid crystal display screens according to an embodiment of the present application;

2 is a schematic diagram of a partial structure of a backlight module of a liquid crystal display screen to which an under-screen fingerprint identification device can be applied in an embodiment of the present application;

3 is a partial structural diagram of a backlight module of a liquid crystal display screen to which another under-screen fingerprint identification device can be applied in an embodiment of the present application;

4 is a schematic diagram of a partial structure of a backlight module of a liquid crystal display that can be applied to another under-screen fingerprint identification device according to an embodiment of the present application;

5 is a partial structural diagram of a backlight module of a liquid crystal display screen to which another under-screen fingerprint identification device can be applied in an embodiment of the present application;

Fig. 6 is a schematic structural diagram of a terminal device according to an embodiment of the present application.

Detailed ways

In order to better understand the technical solutions of the present invention, the following describes the embodiments of the present invention in detail with reference to the accompanying drawings.

It should be clear that the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms of "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

It should be understood that the term "and/or" used in this text is only an association relationship describing the associated objects, indicating that there can be three types of relationships, for example, A and/or B can mean that A alone exists, and both A and A exist at the same time. B, there are three cases of B alone. In addition, the character "/" in this text generally indicates that the associated objects before and after are in an "or" relationship.

It should be understood that although the terms first, second, etc. may be used to describe devices in the embodiments of the present invention, these devices should not be limited to these terms. These terms are only used to distinguish devices from each other. For example, without departing from the scope of the embodiments of the present invention, the first device may also be referred to as the second device, and similarly, the second device may also be referred to as the first device.

Liquid crystal display (LCD) is a display screen that is widely used in electronic devices such as smart mobile terminals. The LCD screen has many advantages such as thin body, low power consumption, and low radiation, and is also widely used in electronic products such as TVs, computers, and mobile phones. The liquid crystal display is a passive light-emitting display device. The liquid crystal panel itself cannot emit light. It is generally necessary to install a backlight module on the back of the liquid crystal display module (or called the liquid crystal module), and use the backlight provided by the backlight module to illuminate. Brighten the LCD panel to display the picture.

The embodiment of the present application provides an under-screen fingerprint identification device suitable for a liquid crystal display screen and a terminal device adopting the above-mentioned under-screen fingerprint identification device.

FIG. 1 is a schematic structural diagram of an under-screen fingerprint identification device suitable for an LCD screen according to an embodiment of the present application; FIG. 2 is a part of a backlight module of a liquid crystal display that can be applied to an under-screen fingerprint identification device according to an embodiment of the present application Schematic diagram of the structure; FIG. 3 is a schematic diagram of a partial structure of a backlight module of a liquid crystal display that can be applied to another under-screen fingerprint identification device in an embodiment of the present application.

As shown in Figures 1 to 3, the under-screen fingerprint identification device 1 includes a fingerprint detection light source 11 and a fingerprint sensor 12; the under-screen fingerprint identification device 1 is applied to a terminal device 2 with a liquid crystal display; among them, the under-screen fingerprint identification device 1 The fingerprint detection area is located in the display area of the liquid crystal display, so that the user can directly press the display area of the liquid crystal display to realize fingerprint input.

The terminal device 2 includes a liquid crystal module 21 and a backlight module 22, which cooperate with each other to form a liquid crystal display screen. Among them, the liquid crystal module 21 can also be called a liquid crystal display module, which includes a liquid crystal panel for displaying images; the backlight module 22 is arranged on the back of the liquid crystal module 21 and is used to provide a backlight for the liquid crystal module 21 for illumination. Brighten the LCD panel and make it displayable.

In this embodiment, the liquid crystal module 21 and the fingerprint detection light source 11 are located on one side of the backlight module 22, such as the light emitting side of the backlight module 22; the fingerprint sensor 12 is located on the side of the backlight module 22 away from the liquid crystal module 21, That is, it is arranged under the backlight module 22. Wherein, the effective field of view (FOV) area of the fingerprint sensor 12 corresponds to the fingerprint detection area of the liquid crystal display screen.

The fingerprint detection light source 11 may be an invisible light source with a specific wavelength, and is used to emit a specific wavelength of invisible light to the finger above the liquid crystal display screen as the detection light to form fingerprint detection light carrying fingerprint information on the finger. As a specific embodiment, the fingerprint detection light source 11 may specifically be an infrared supplementary light lamp, which may emit infrared light with a specific wavelength as the aforementioned detection light.

As shown in FIG. 1, in an embodiment, the terminal device 2 may further include a glass cover plate 20, which can be used as a protective cover plate of the liquid crystal display, covering the liquid crystal module 21 of the liquid crystal display. The glass cover 20 has an edge extension relative to the liquid crystal module 21, the edge extension corresponds to the edge non-display area (such as the chin area) of the terminal device 2, and the bottom of the edge extension can generally be used as The wiring area of the liquid crystal module 21, such as a circuit board connected to the liquid crystal module 21 (also referred to as a liquid crystal FPC), can be arranged below the edge extension and extend to other areas to connect to other peripheral circuits. In this embodiment, the fingerprint detection light source 11 may be arranged under the edge extension of the glass cover 20, and the glass cover 20 emits detection light toward the finger above the liquid crystal display at a preset inclination angle, and the detection light illuminates After reaching the finger, it scatters on the finger and transmits the finger through the surface of the finger to form fingerprint detection light carrying the fingerprint information of the finger; the fingerprint detection light can return to the glass cover 20 and further pass through the liquid crystal module 21 and After the backlight module 22, it is received by the fingerprint sensor 12 under the backlight module 22 to obtain the fingerprint image of the finger.

The fingerprint sensor 12 may be an optical sensor, which includes an optical imaging chip or an optical image sensor chip, and may also be referred to as an optical fingerprint sensor chip. The fingerprint sensor 12 may specifically include an optical sensing array having a plurality of optical sensing units and an optical path guiding structure formed above the optical sensing array. The optical path guiding structure is used for guiding the fingerprint detection light formed on the finger and passing through the liquid crystal display to the optical sensing array. In addition, the fingerprint sensor 12 may also include a filter to filter out ambient light or other interference light entering the optical sensing array. For example, the filter may allow infrared light corresponding to the fingerprint detection light. Pass, and filter out the optical signals of other bands.

As a specific embodiment, the optical path guiding structure may include a macro lens with at least one spherical or aspheric lens, and a lens barrel or lens holder for carrying the macro lens. The lens barrel or lens holder is arranged on a soft Above the flexible circuit board and forming a closed space with the flexible circuit board, the optical sensor array and the optical filter above it can be arranged in the above-mentioned closed space and located in the converging light path of the macro lens; wherein, the micro The distance lens is used to guide or converge the fingerprint detection light passing through the backlight module 22 to the optical sensor array to realize the optical fingerprint imaging of the finger on the optical sensor array. For example, the macro lens may pass through multiple non-magnetic sensors. The spherical lens is combined with the micro-aperture diaphragm between the lenses to achieve macro imaging under the condition of a larger effective field of view, so as to meet the needs of the special application scenario of fingerprint recognition under the screen.

As another specific embodiment, the optical path guiding structure may also be an optical path guiding layer formed above the optical sensor array by a semiconductor process, and the optical path guiding layer may include a microlens array and an optical path between the microlens array and the optical sensor array. Multiple light-blocking layers, multiple light-blocking layers respectively define multiple transmission light paths between the microlens array and the optical sensor array through openings, each microlens of the microlens array can focus the fingerprint detection light to its corresponding The transmission light path is transmitted to the corresponding optical sensing unit through the transmission light path. Wherein, the filter can be directly formed on the optical sensing array or the optical path guiding structure by coating.

The backlight module 22, the liquid crystal module 21, and the glass cover 20 are arranged in sequence in the vertical direction of the display surface of the liquid crystal display. First, the backlight module 22 provides visible light as a backlight, and the visible light illuminates the liquid crystal module 21 so that the liquid crystal module 21 can display images and be viewed by the user through the glass cover 20.

The backlight module 22 may include a backlight light source and a plurality of optical films, such as a brightness enhancement film 221, a uniform light film 222, a light guide plate 223, a reflective film 224, a steel plate 225, and a backlight light source. Among them, the brightness enhancement film 221, the light homogenizing film 222, the light guide plate 223, the reflective film 224, and the steel plate 225 are sequentially arranged in the vertical direction of the display surface of the liquid crystal display. The backlight light source and the light guide plate 223 are relatively arranged in a direction parallel to the plane where the light guide plate 223 is located. One of the sides of the light guide plate 223 can be defined as a light incident surface, and the backlight light source 223 is arranged on the light incident surface side of the light guide plate 223, and can be It is located below the edge extension of the glass cover 20. First, the backlight source emits visible light, and the visible light enters the light guide plate toward the light-incident surface of the light guide plate 223, and most of the visible light guide plate 223 is guided to transmit toward the uniform light film 222 and the brightness enhancement film 221. In addition, a part of the visible light may be transmitted to the reflective film 224 under the light guide plate 223. The reflective film 224 can reflect the visible light to the light guide plate 223, and is further guided to the uniform light film 222 and the brightness enhancement film 221 by the light guide plate 223. The homogenizing film 222 can perform homogenization or fogging and diffusion of visible light, so that the backlight output by the backlight module 22 is more uniform. The brightness enhancement film 221 can perform optical brightness enhancement after homogenization or fogging and diffusion treatment, so as to increase the brightness of the backlight output by the backlight module 22.

Here, the thickness of the brightness enhancement film 221, the light homogenizing film 222, the light guide plate 223, and the reflective film 224 are not limited. The thickness of the brightness enhancement film 221, the light homogenizing film 222, the light guide plate 223, and the reflective film 224 are determined according to actual design. For example, the thickness of the reflective film 224 is 80 micrometers. The thickness of the light guide plate 223 is 450 microns. The thickness of the homogenizing film 222 is 50 microns. As shown in FIG. 3, the brightness enhancement film 221 includes a plane film 221B with a thickness of 70 microns; or, as shown in FIG. 2, the brightness enhancement film 221 includes two prism films 221A, and two prism films 221A are formed on them. They are arranged in the vertical direction of the plane, and their thickness is 130 microns.

In order that the fingerprint detection light formed by the finger above the liquid crystal display can pass through the backlight module 22 and reach the fingerprint sensor 12 below it, the backlight module 22 may be provided with a transparent portion that allows the fingerprint detection light to pass through. The specific structure can be implemented in multiple ways. For example, the above-mentioned transmissive portion can be provided with a translucent opening in a part of the non-transmissive optical film of the backlight module 22 or an optical film that can transmit infrared light of a specific wavelength is used. to realise.

For example, the fingerprint sensor 12 is located on the side of the reflective film 224 and the steel plate 225 away from the light guide plate 223, that is, under the steel plate 225. The steel plate 225 may be formed with a light-transmitting opening in the area where the fingerprint sensor 12 is located to expose the fingerprint sensor 12 so that fingerprint detection light can pass through the light-transmitting opening and enter the fingerprint sensor 12 through the steel plate 225. On the other hand, other optical films of the backlight module 200 (including the brightness enhancement film 221, the light homogenizing film 222, the light guide plate 223, and the reflective film 224) may be film materials with different optical characteristics for light sources of different wavelengths, such as the above-mentioned optical film. The film may have high transmittance characteristics for the fingerprint detection light formed on the finger (corresponding to the infrared detection light of a specific wavelength emitted by the fingerprint detection light source 11), and the visible light provided by the backlight light source may have the traditional above-mentioned film The optical properties of the material itself, such as optical brightening, uniform light atomization, light guiding treatment and optical reflection, etc.

When the fingerprint identification device 1 under the screen performs fingerprint detection, the user's finger presses and touches the glass cover 20 above the liquid crystal display, the fingerprint detection light source 11 emits infrared light as the detection light for fingerprint detection, and the infrared light passes through the glass cover 20 Illuminated to the finger above the glass cover 20, and after entering the finger, the finger is scattered and transmitted through the surface of the finger to form a fingerprint detection light carrying fingerprint information of the finger. Then, the fingerprint detection light returns to the glass cover 20 and enters the backlight module 22 through the liquid crystal module 21, and further passes through the brightness enhancement film 221, the light homogenizing film 222, the light guide plate 22, and the reflective film 224, and then passes through the steel plate 225 The light-transmitting opening enters the fingerprint sensor 12. The fingerprint sensor 12 further guides the fingerprint detection light to its optical sensing array through its optical path guiding structure, and the optical sensing array receives the fingerprint detection light and performs photoelectric conversion to obtain the fingerprint image of the finger.

In the above process, the fingerprint detection light needs to penetrate the brightness enhancement film 221 and the uniform light film 222 of the backlight module 22. In the embodiment of the present application, as shown in FIGS. 2 and 3, anti-adsorption particles 23 are provided between the brightness enhancement film 221 and the light homogenizing film 222; on the one hand, the brightness enhancement film 221 is located at the anti-adsorption particles 23 away from the light homogenizing film. The side of 222 is located above the anti-adsorption particles 23; when the finger presses the fingerprint input, the pressure of the finger is transmitted to the brightness enhancement film 221 and may cause certain deformation of the brightness enhancement film 221. At this time, the brightness enhancement film 221 The bottom surface contacts the anti-adsorption particles 23 below it. On the other hand, the uniform light film 222 is located on the side of the anti-adsorption particles 23 away from the brightness enhancement film 221, that is, under the anti-adsorption particles 23; the upper surface of the uniform light film 222 contacts the anti-adsorption particles 23 above it. In short, the anti-adsorption particles 23 are located between the homogenization film 222 and the brightness enhancement film 221, so that even if the brightness enhancement film 221 is deformed when pressed by a finger, the homogenization film 222 and the brightness enhancement film 221 are not in contact with each other. On the other hand, the anti-adsorption particles 23 can make the uniformity film 222 and the brightness enhancement film 221 formed a sufficient anti-absorption distance, such as the distance between the uniformity film 222 and the brightness enhancement film 221 and the fingerprint detection light source 11 emission The ratio of the wavelength of the probe light is greater than one-half. Therefore, the anti-adsorption particles 23 can physically isolate the homogenization film 222 and the brightness enhancement film 221 to prevent the homogenization film 222 and the brightness enhancement film 221 from adsorbing each other when deformed; or, through the anti-adsorption particles 23 in the homogenization film 222 and The brightness enhancement film 221 forms a sufficient anti-absorption distance to destroy the interference fringes formed between the uniform brightness film 222 and the brightness enhancement film 221. Therefore, the fingerprint detection light can pass through the homogenization film 222 and the brightness enhancement film 221 without causing interference fringes, thereby avoiding the fingerprint identification of the under-screen fingerprint identification device 1 from being affected by the interference fringes, and ensuring that the under-screen fingerprint identification device 1 is low. Fingerprint recognition performance.

As shown in FIGS. 1 to 3, the anti-adsorption particles 23 may be light-transmitting and anti-adsorption particles formed of a light-transmitting material. In a specific embodiment, the anti-adsorption particles 23 may be formed on the bottom surface of the brightness enhancement film 221; or, In other alternative embodiments, the anti-adsorption particles 23 may also be formed on the upper surface of the light homogenizing film 222.

In the embodiment of the present application, the anti-adsorption particles 23 are made of light-transmitting materials, and the fingerprint detection light can directly pass through the anti-adsorption particles 23. Therefore, the anti-adsorption particles 23 do not prevent the under-screen fingerprint identification device 1 from identifying fingerprints. At the same time, because the anti-adsorption particles 23 use light-transmitting materials, the visible light provided by the backlight module 22 can also directly pass through the anti-adsorption particles 23. Therefore, the anti-adsorption particles 23 do not prevent the backlight module 22 from providing the liquid crystal module 21. Backlight.

As shown in FIGS. 1 to 3, in this embodiment, by disposing the anti-adsorption particles 23 between the homogenization film 222 and the brightness enhancement film 221, the distance between the homogenization film 222 and the brightness enhancement film 221 is the same as the fingerprint detection light source. The ratio of the emission wavelength of 11 (that is, the detection light emitted by the fingerprint detection light source and the wavelength of the fingerprint detection light formed by the fingerprint detection light source) is greater than one-half, that is, the anti-adsorption particles 23 are the uniform light film 222 and the brightness enhancement film 221 Provide sufficient anti-absorption spacing between.

Since the ratio of the distance between the uniform light film 222 and the brightness enhancement film 221 to the emission wavelength of the fingerprint detection light source 11 is greater than one half. For example, the light emission wavelength of the fingerprint detection light source 11 is 940 nanometers, and the distance between the homogenization film 222 and the brightness enhancement film 221 is greater than 470 nanometers; therefore, there is sufficient anti-absorption formation between the homogenization film 222 and the brightness enhancement film 221. The distance makes the fingerprint detection light pass through the brightness enhancement film 221 and the light homogenizing film 222 without causing Newton’s rings, avoiding the under-screen fingerprint identification device 1 from being interfered by Newton’s rings during the fingerprint identification process, and effectively improving the performance of the under-screen fingerprint identification device 1. Fingerprint recognition performance.

FIG. 4 is a schematic diagram of a partial structure of a backlight module of a liquid crystal display screen to which another under-screen fingerprint identification device can be applied in an embodiment of the present application.

As shown in FIG. 4, the backlight module 22 also includes haze particles 24. The haze particles 24 are located between the light homogenizing film 222 and the brightness enhancement film 221, and are mainly used to prevent light passing through the light homogenization film 222 and the brightness enhancement film 221. The visible light is subjected to uniform light atomization, and most of the invisible light (such as infrared light) of a specific wavelength emitted by the fingerprint detection light source 11 can directly penetrate the haze particles 24 without being substantially affected by the uniform light atomization effect. On the other hand, as shown in FIG. 4, there may be a certain gap between the haze particles 24 and the anti-adsorption particles 23. For example, the anti-adsorption particles 23 can be formed on the lower surface of the brightness enhancement film 221, and the haze particles 24 can be formed on the lower surface of the brightness enhancement film 221. The upper surface of the homogenizing film 222 is not in contact with each other.

In the embodiment of the present application, on the one hand, the visible light provided by the backlight module 22 can pass through the homogenization film 222 and the brightness enhancement film 221. Since the haze particles 24 are located between the homogenization film 222 and the brightness enhancement film 221, Improve the uniformity of visible light; therefore, the backlight module 22 has excellent backlight uniformity. On the other hand, the fingerprint detection light formed by irradiating the finger with the detection light emitted by the fingerprint detection light source 11 can be transmitted to the fingerprint sensor 12 through the brightness enhancement film 221 and the homogenization film 222. Since the haze particles 24 are located between the homogenization film 222 and the brightness enhancement film 221, they can cooperate with the anti-adsorption particles 23 to further physically isolate the homogenization film 222 and the brightness enhancement film 221 from each other, and further avoid the homogeneity film 222 and the brightness enhancement film 221. The bright film 221 deforms when pressed by a finger, and attracts each other. Therefore, the fingerprint detection light passing through the homogenizing film 222 and the brightness enhancing film 221 will not produce interference fringes, which effectively prevents the fingerprint identification device 1 under the screen from being interfered by the fringes and affecting the fingerprint identification performance.

As an optional embodiment, the haze particles 24 can also be used as a part of the light uniform film 222; for example, the light uniform film 222 can include a substrate and a haze particle layer, and the haze particle layer includes a layer formed on the substrate. The upper surface of the haze particles 24.

As shown in FIGS. 2 to 4, the surface of the brightness enhancement film 221 close to the liquid crystal module 21 includes a microprism structure 2211. Specifically, the brightness enhancement film 221 may include a main body 2212 and a prism structure layer formed on the upper surface of the main body 2212. The prism structure layer 2211 includes a microprism structure 2211 protruding toward the liquid crystal module 21.

In the embodiment of the present application, the surface of the brightness enhancement film 221 close to the liquid crystal module 21 includes a microprism structure 2211. The microprism structure 2211 can increase the brightness of visible light in the vertical direction of the brightness enhancement film 221, thereby improving the backlight module. 22 backlight brightness. on the other hand,. The microprism structure 2211 of the brightness enhancement film 221 can realize the physical isolation between the main body 2212 of the brightness enhancement film 221 and the liquid crystal module 21, and prevent the main body 2212 of the brightness enhancement film 221 and the liquid crystal module 21 from deforming when pressed by a finger Occasionally, mutual contact occurs and mutual adsorption occurs, so that the fingerprint detection light passes through the liquid crystal module 21 and the brightness enhancement film 22 without interference fringes, which effectively prevents the fingerprint identification device 1 under the screen from being interfered by the aforementioned fringes and affecting its fingerprint identification effect.

FIG. 5 is a partial structural diagram of a backlight module of a liquid crystal display screen to which another under-screen fingerprint identification device can be applied in an embodiment of the present application.

As shown in FIG. 5, the brightness enhancement film 221 includes multiple layers of organic film materials with different refractive indexes. For example, the refractive index of the multilayer organic film materials can be sequentially reduced in the vertical direction of the brightness enhancement film 221, thereby achieving the same The brightness enhancement film adopting the microprism structure has the same brightness enhancement effect, and the visible light provided by the backlight module 22 can be constrained to the front light by multiple layers of organic film materials with different refractive indexes to enhance the visible light output to the liquid crystal module 21 from the front On the other hand, the above-mentioned multi-layer organic film materials with different refractive indexes have basically no effect on the invisible light (such as infrared light) of a specific wavelength emitted by the fingerprint detection light source 11. Therefore, the fingerprint detection light can directly penetrate the A brightness enhancement film 221 made of multiple layers of organic film materials with different refractive indices.

In this embodiment, since the brightness enhancement film is formed of multiple layers of organic film materials with different refractive indices, the surface of the brightness enhancement film 221 generally has no microphysical structure, that is, the surface of the brightness enhancement film 221 close to the liquid crystal module 21 is smooth, which may When the brightness enhancement film 221 is deformed, it contacts with the liquid crystal module 21 and attracts each other and produces interference fringes. At the same time, the surface of the brightness enhancement film 221 close to the homogenization film 222 is also smooth, and may also contact the liquid crystal module 21 when the brightness enhancement film 221 is deformed, causing mutual adsorption and interference fringes.

As shown in FIG. 5, the anti-adsorption particles 23 can be formed between the brightness enhancement film 221 and the light homogenizing film 222 as in the previous embodiment, and can also be further formed between the liquid crystal module 21 and the brightness enhancement film 221. For example, the bottom surface of the bottommost organic film material of the brightness enhancement film 221 (that is, the bottom surface of the brightness enhancement film 221) may be formed with a first anti-adsorption particle layer, and the upper surface of the topmost organic film material (that is, the brightness enhancement film 221) The top surface of the film) may be formed with a second anti-adsorption particle layer, and both the first anti-adsorption particle layer and the second anti-adsorption particle layer include anti-adsorption particles 23.

In this embodiment, since the brightness enhancement film 221 is close to the surface of the liquid crystal module 21 and the surface close to the homogenizing film 222 is formed with anti-adsorption particles 23, the anti-adsorption particles 23 can prevent the brightness enhancement film 221 from being deformed. The upper and lower surfaces are in contact with the liquid crystal module 21 and the homogenizing film 222 respectively, causing mutual adsorption and interference fringes, which effectively improves the fingerprint recognition effect of the under-screen fingerprint recognition device 1.

As shown in FIG. 5, the anti-adsorption particles 23 can also make the brightness enhancement film 221 and the liquid crystal module 21 have a sufficient anti-adsorption distance to destroy the conditions for mutual adsorption of the two. Specifically, the liquid crystal module 21 and the liquid crystal module 21 The ratio of the distance between the bright films 221 to the emission wavelength of the fingerprint detection light source is greater than one-half.

For example, the light-emitting wavelength of the fingerprint detection light source 11 is 940 nanometers, and the distance between the liquid crystal module 21 and the brightness enhancement film 221 is greater than 470 nanometers. Therefore, a sufficient anti-absorption distance is formed between the liquid crystal module 21 and the brightness enhancement film 221 Therefore, the fingerprint detection light can pass through the liquid crystal module 21 and the brightness enhancement film 221 without causing a Newton ring, so as to prevent the under-screen fingerprint recognition device 1 from being interfered by the Newton ring during the fingerprint recognition process and affecting its fingerprint recognition performance.

Further, as shown in FIG. 5, the liquid crystal module 21 and the brightness enhancement film 221 may also be provided with haze particles 24, that is, between the liquid crystal module 21 and the brightness enhancement film 221, anti-adsorption particles 23 may be formed at the same time. And haze particles 24. For example, the above-mentioned anti-adsorption particles 23 and haze particles 24 can be formed on the upper surface of the brightness enhancement film 221 at the same time; wherein, the haze particles 24 on the upper surface of the brightness enhancement film 221 can be formed on the uniform light film 24 as shown in FIG. The haze particles 24 are consistent.

As an implementation solution, the anti-adsorption particles 23 and the haze particles 24 on the upper surface of the brightness enhancement film 221 can be realized by forming an anti-adsorption particle layer and a haze particle layer on the upper surface of the brightness enhancement film 221, respectively, wherein the haze The particle layer may coat the anti-adsorption particles 23 described above. Alternatively, the aforementioned anti-adsorption particles 23 and haze particles 24 can also be realized by forming a composite particle layer on the upper surface of the brightness enhancement film 221, that is, the composite particle layer includes the anti-adsorption particles 23 and the haze particles 24.

In this embodiment, the anti-adsorption particles 23 and the haze particles 24 are provided on the upper surface of the brightness enhancement film 221 at the same time. The anti-adsorption particles 23 and the haze particles 24 cooperate with each other to further reduce and avoid the deformation of the brightness enhancement film 221. When the time and the liquid crystal module 21 are attracted to each other and produce interference stripes, the fingerprint recognition effect of the under-screen fingerprint recognition device 1 is effectively improved.

As shown in Figures 1 and 6, the terminal equipment 2 includes a liquid crystal display and an under-screen fingerprint identification device 1 arranged below the liquid crystal display; the liquid crystal display includes a liquid crystal module 21 and a backlight module 22. Covered with a glass cover 20; the under-screen fingerprint identification device 1 includes a fingerprint detection light source 11 and a fingerprint sensor 12. The fingerprint detection light source 11 can be an infrared fill light, which is located under the edge extension of the glass cover 20, and the fingerprint sensor 12 is provided Below the backlight module 22. The specific structure and working process of the liquid crystal display screen and the under-screen fingerprint identification device 1 can be referred to the description of the above-mentioned embodiment.

The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the present invention. Within the scope of protection.

Claims

An under-screen fingerprint identification device, suitable for terminal equipment with a liquid crystal display screen, characterized in that the under-screen fingerprint identification device includes a fingerprint sensor, and the fingerprint sensor is used for a backlight module provided on the liquid crystal display screen Below to realize fingerprint detection under the screen;

The fingerprint sensor includes an optical sensing array with a plurality of optical sensing units, and the optical sensing array is used to receive the detection light emitted by the fingerprint detection light source irradiating the fingerprint detection light formed by the finger above the liquid crystal display screen to obtain The fingerprint image of the finger; wherein the fingerprint detection light is transmitted to the fingerprint sensor after passing through the liquid crystal module and the backlight module of the liquid crystal display, and the backlight module includes a brightness enhancement film and a homogenization film And anti-adsorption particles, wherein the anti-adsorption particles are located between the brightness enhancement film and the uniform light film.
The under-screen fingerprint identification device according to claim 1, wherein the anti-adsorption particles are light-transmitting anti-adsorption particles formed of a light-transmitting material, which are used to isolate the brightness enhancement film from the uniform light Membrane to prevent the two from adsorbing each other.
The under-screen fingerprint identification device according to claim 1, wherein there is a predetermined anti-absorption distance between the homogenizing film and the brightness enhancement film, and the anti-absorption distance is related to the light emission of the fingerprint detection light source. The ratio of wavelengths is greater than one-half.
The under-screen fingerprint identification device according to claim 3, wherein the anti-adsorption particles are formed on the lower surface of the brightness enhancement film or on the upper surface of the homogenizing film, and the brightness enhancement film The anti-adsorption distance between the uniform light film and the anti-adsorption film is formed by the anti-adsorption particles.
The under-screen fingerprint identification device according to claim 3, wherein the fingerprint detection light source is an infrared supplementary light, and the infrared supplementary light is used to emit infrared light of a specific wavelength to the finger above the liquid crystal display. The infrared light is used as the detection light to form the fingerprint detection light on the finger.
The under-screen fingerprint identification device according to claim 1, wherein the brightness enhancement film comprises a main body and a microprism structure formed on the upper surface of the main body, and the microprism structure is used for the backlight module The brightness of the provided visible light in the vertical direction of the brightness enhancement film; the anti-adsorption particles are formed on the lower surface of the main body of the brightness enhancement film.
The under-screen fingerprint identification device according to claim 1, wherein the brightness enhancement film comprises multiple layers of organic film materials with different refractive indexes and adopting a non-prism structure, which are used to pass through the multiple layers of different refractive index materials. The organic film material makes the visible light provided by the backlight module constrain the vertical direction of the brightness enhancement film to improve the brightness of the visible light output by the backlight module.
The under-screen fingerprint identification device according to claim 7, wherein the upper surface of the brightness enhancement film close to the liquid crystal module and the lower surface close to the homogenizing film are both smooth surfaces, and the Anti-adsorption particles are also formed between the brightness enhancement film and the liquid crystal module.
8. The under-screen fingerprint identification device according to claim 8, wherein the ratio of the distance between the brightness enhancement film and the liquid crystal module to the luminous wavelength of the fingerprint detection light source is greater than one-half.
The under-screen fingerprint identification device according to claim 1, wherein haze particles are also formed between the homogenizing film and the brightness enhancement film, and the haze particles are used to contrast the backlight module The provided visible light is homogenized and fogged, and the fingerprint detection light can penetrate the haze particles.
The under-screen fingerprint identification device according to claim 10, wherein the haze particles are used to cooperate with the anti-adsorption particles to further prevent mutual adsorption between the brightness enhancement film and the uniform light film.
The under-screen fingerprint identification device according to claim 11, wherein the haze particles are formed on the upper surface of the homogenizing film, and the anti-absorption particles are formed on the lower surface of the brightness enhancement film, And there is a gap between the two.
The under-screen fingerprint identification device according to claim 1, wherein anti-adsorption particles and haze particles are formed between the brightness enhancement film and the liquid crystal module at the same time, and the anti-adsorption particles and the fog are formed at the same time. The degree particles cooperate with each other to prevent mutual adsorption between the brightness enhancement film and the liquid crystal module.
The under-screen fingerprint identification device according to claim 13, wherein the anti-adsorption particles and haze particles between the brightness enhancement film and the liquid crystal module are respectively formed on the upper surface of the brightness enhancement film The anti-adsorption particle layer and the haze particle layer can be realized, wherein the haze particle layer can coat the anti-adsorption particles on the upper surface of the brightness enhancement film.
The under-screen fingerprint identification device according to claim 13, wherein the anti-adsorption particles and haze particles between the brightness enhancement film and the liquid crystal module form a composite on the upper surface of the brightness enhancement film. A particle layer is implemented, and the composite particle layer includes the anti-adsorption particles and the haze particles.
The under-screen fingerprint identification device according to claim 1, wherein the liquid crystal module is covered with a glass cover, the glass cover has an edge extension relative to the liquid crystal module, and the fingerprint The detection light source is arranged below the edge extension portion, and emits the detection light to the finger above the liquid crystal display at a predetermined inclination angle.
The under-screen fingerprint identification device according to claim 16, wherein the fingerprint sensor further comprises a light path guide structure formed above the optical sensor array, and the light path guide structure is used to pass through the liquid crystal display The fingerprint detection light is guided to the optical sensing array.
The under-screen fingerprint identification device according to claim 17, wherein the optical path guiding structure comprises a macro lens with a plurality of aspheric lenses and a lens barrel or lens holder for carrying the macro lens, and the lens The tube or lens holder is arranged above the flexible circuit board and forms a closed space with the flexible circuit board, and the optical sensing array is arranged in the closed space and located in the converging light path of the macro lens; wherein, the micro The distance lens is used to achieve macro imaging with an enlarged effective field of view through the multiple aspheric lenses and the micro-aperture diaphragm between the lenses, so as to converge the fingerprint detection light passing through the liquid crystal display To the optical sensor array and realize the optical fingerprint imaging of the finger on the optical sensor array.
The under-screen fingerprint identification device according to claim 17, wherein the light path guiding structure comprises a light path guiding layer formed above the optical sensor array by a semiconductor process, and the light path guiding layer comprises a microlens array and A plurality of light blocking layers between the micro lens array and the optical sensor array, the plurality of light blocking layers respectively define a plurality of transmission light paths between the micro lens array and the optical sensor array through openings, wherein the micro lens array Each microlens is used to focus the fingerprint detection light to its corresponding transmission optical path, and then transmit it to the corresponding optical sensing unit through the transmission optical path.
The under-screen fingerprint identification device according to claim 19, wherein the optical sensor further comprises a filter, and the filter is formed on the optical sensing array or the optical path guide structure by a coating method for filtering In addition to the interference light entering the optical sensing array.
A terminal device, which is characterized by comprising a liquid crystal display screen with a liquid crystal module and a backlight module, and an under-screen optical fingerprint identification device arranged below the liquid crystal display, wherein the under-screen optical fingerprint identification device is such as The under-screen optical fingerprint device according to any one of claims 1 to 20.