CN111007680A

CN111007680A - Liquid crystal display device having a plurality of pixel electrodes

Info

Publication number: CN111007680A
Application number: CN201911168873.2A
Authority: CN
Inventors: 余俊逸; 陈栋; 宋连燕
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2019-11-25
Filing date: 2019-11-25
Publication date: 2020-04-14
Also published as: WO2021103888A1

Abstract

The application provides a liquid crystal display device, including: the backlight module is positioned between the liquid crystal panel and the fingerprint module, and the fingerprint module is used for receiving light reflected by a finger of a user; the backlight module includes: the light guide plate comprises a light-emitting surface, a backlight surface and a side surface, wherein the light-emitting surface and the backlight surface are oppositely arranged, and the side surface is connected with the light-emitting surface and the backlight surface; a light source adjacent to a side surface of the light guide plate; at least one prism sheet arranged on one side of the light emergent surface of the light guide plate; the prism sheet comprises a substrate with uniform thickness and a plurality of prism microstructures protruding from the substrate, wherein each prism microstructure comprises a transmission plane parallel to the substrate, and/or a preset distance is reserved between every two adjacent prism microstructures in the prism microstructures. According to the technical scheme, the liquid crystal display device can improve the accuracy of fingerprint identification under the screen.

Description

Liquid crystal display device having a plurality of pixel electrodes

Technical Field

The present application relates to the field of display technology, and more particularly, to a liquid crystal display device.

Background

With the continuous development of terminal technology, the functions of electronic devices such as mobile phones and the like tend to be diversified, and the size requirements of users on screens are higher and higher. In pursuit of higher screen occupation ratio to provide better user experience for users, more and more mobile terminals such as mobile phones and the like adopt an underscreen fingerprint recognition technology.

Fingerprint identification technique under the screen means to accomplish fingerprint identification in the screen below, and need not finger and fingerprint module contact. The mainstream optical type under-screen fingerprint identification technology mainly utilizes the refraction and reflection principle of light to realize fingerprint identification, so that the requirement on the light transmission of the screen is higher.

Because Liquid Crystal Display (LCD) thickness is thicker, and light transmission performance is not good, the light that is emitted by the fingerprint module passes through the LCD of certain thickness and reaches the finger, and the luminous intensity of shining the finger has reduced, shines the light of fingerprint after-reflection and returns on the way again, and the energy of the light that the fingerprint module received is very low for fingerprint identification's the degree of difficulty is very high.

Disclosure of Invention

The application provides a liquid crystal display device, can improve the precision of fingerprint discernment under the screen.

In a first aspect, there is provided a liquid crystal display device including: the backlight module is positioned between the liquid crystal panel and the fingerprint module, and the fingerprint module is used for receiving light reflected by a finger of a user; the backlight module includes: the backlight module comprises a light guide plate and a light source, wherein the light guide plate comprises a light-emitting surface, a backlight surface and a side surface, the light-emitting surface and the backlight surface are oppositely arranged, and the side surface is connected with the light-emitting surface and the backlight surface; a light source adjacent to the side surface of the light guide plate; the prism sheet is arranged on one side of the light emergent surface of the light guide plate; the prism sheet comprises a substrate with uniform thickness and a plurality of prism microstructures protruding from the substrate, wherein each prism microstructure comprises a transmission plane parallel to the substrate, and/or a preset distance is reserved between two adjacent prism microstructures in the prism microstructures.

It is to be understood that the prismatic microstructures include a transmission plane parallel to the substrate, and/or that adjacent two prismatic microstructures in the plurality of prismatic microstructures have a predetermined pitch therebetween, including three cases:

the prismatic microstructure comprises a transmission plane parallel to the substrate; a preset distance is reserved between every two adjacent prism microstructures in the plurality of prism microstructures; the prism microstructures comprise a transmission plane parallel to the substrate, and a preset distance is reserved between two adjacent prism microstructures in the prism microstructures.

In the embodiment of the application, the fingerprint module among the liquid crystal display device can receive the light that the user pointed the reflection, and liquid crystal display device can utilize the light that the finger reflected to come to gather and discern the user fingerprint like this, can realize fingerprint identification under the optical screen. The prism microstructure of the prism sheet comprises a transmission plane parallel to the substrate, and in the light reflected by the finger of a user, the light passing through the transmission plane can directly pass through the prism microstructure and the substrate, so that the light transmittance of the prism sheet in the front viewing direction is improved, the energy of the reflected light received by the fingerprint module is enhanced, and the accuracy of fingerprint identification under the screen is improved. Similarly, when two adjacent prism microstructures in the plurality of prism microstructures have a preset interval, namely the plurality of prism microstructures are arranged at intervals, light passing through the interval between the two adjacent prism microstructures can directly pass through the substrate from light reflected by a finger of a user, the transmittance of the prism sheet on light in the front view direction is improved, so that the fingerprint module receives reflected light energy and enhances the accuracy of fingerprint identification under the screen.

With reference to the first aspect, in one possible implementation manner, the width of the transmission plane is greater than 0 and less than or equal to 6 micrometers.

It is to be understood that the width direction of the transmission plane is the arrangement direction of the plurality of prism microstructures.

With reference to the first aspect, in one possible implementation manner, the preset pitch is greater than 0 and less than or equal to 6 micrometers.

Alternatively, the predetermined pitch between the prism microstructures may be the same or different.

With reference to the first aspect, in a possible implementation manner, in a case that the prism microstructure includes a transmission plane parallel to the substrate, the prism microstructure further includes a plurality of inclined planes and/or arc planes intersecting with the substrate, and the transmission plane connects two adjacent planes of the plurality of inclined planes and/or arc planes.

It will be appreciated that prismatic microstructures also include a plurality of inclined and/or curved faces that intersect the base, including three cases: the prismatic microstructure further comprises a plurality of inclined planes intersecting the substrate; the prism microstructure further comprises a plurality of cambered surfaces intersected with the substrate; the prismatic microstructure further comprises at least one inclined surface and at least one cambered surface intersecting the substrate.

Optionally, the prismatic microstructure further comprises a first inclined face and a second inclined face intersecting the substrate, and the transmission plane connects the first inclined face and the second inclined face. That is, the cross-sectional shape of the prism microstructure is trapezoidal.

Optionally, an included angle between the first inclined surface and the substrate is less than 90 °, and an included angle between the second inclined surface and the substrate is less than 90 °. Preferably, the included angle between the first inclined surface and the substrate is equal to the included angle between the second inclined surface and the substrate, and is equal to 45 °.

With reference to the first aspect, in a possible implementation manner, when a preset pitch exists between two adjacent prism microstructures in the plurality of prism microstructures, a cross-sectional shape of each prism microstructure is any one of a triangle, a trapezoid and a semicircle.

Alternatively, the cross-sectional shape of the prismatic microstructure may also be a pattern surrounded by straight lines or curved lines.

With reference to the first aspect, in a possible implementation manner, the prism sheet is a forward prism sheet, and the prism microstructures are disposed opposite to the liquid crystal panel.

With reference to the first aspect, in a possible implementation manner, the cross-sectional shape of the prism microstructure is an isosceles trapezoid, and a base angle of the isosceles trapezoid is 45 °.

It will be understood that where the prismatic structure is an isosceles trapezoid, the base angles of the isosceles trapezoid will be understood to be the angles near the base.

When the cross section of the prism microstructure is in an isosceles trapezoid shape and the base angle is 45 degrees, the prism microstructure is a prism. The plane of the prism corresponding to the two waists of the isosceles trapezoid corrects the light with a certain incident angle to the front viewing direction, so that the brightness of the liquid crystal panel is enhanced, the transmittance of the directional light such as the direct light in the front viewing direction can be improved, and the energy of the reflected light received by the fingerprint module is enhanced.

With reference to the first aspect, in a possible implementation manner, the prism sheet is an inverse prism sheet, and the prism microstructures are disposed opposite to the light guide plate.

With reference to the first aspect, in one possible implementation manner, the cross-sectional shape of the prism microstructure is a triangle, and the vertex angle of the triangle is 60 ° to 70 °.

Optionally, the cross-sectional shape of the prismatic microstructure is a triangle, and the apex angle of the triangle is 68 °.

Adopt the anti-prism piece in backlight unit, both can strengthen liquid crystal display panel's luminance, after the light of fingerprint reflection passed the anti-prism piece, it is little to the divergence degree of reverberation, and fingerprint module can gather more clear fingerprint image, improves the fingerprint identification precision.

With reference to the first aspect, in a possible implementation manner, the fingerprint module includes an infrared transmitter-receiver configured to transmit infrared rays to one side of the liquid crystal panel and receive infrared rays reflected by a finger of a user.

The fingerprint module can be to liquid crystal display panel side transmission infrared light, and the infrared light that receives the finger reflection, when adopting foretell backlight unit and prism piece, the prism piece improves to the transmittance of once light-emitting of infrared light of directive liquid crystal display panel orthographic view direction, and the light energy that arrives the finger like this is higher, and the fingerprint module receives the infrared light energy reinforcing of reflection, has improved fingerprint identification's precision.

With reference to the first aspect, in a possible implementation manner, the backlight module further includes at least one diffusion sheet and a reflection sheet, the at least one diffusion sheet is located between the light guide plate and the at least one prism sheet, and the reflection sheet is located on the backlight surface side of the light guide plate.

With reference to the first aspect, in a possible implementation manner, the liquid crystal display device further includes a cover glass, and the cover glass is disposed on a side of the liquid crystal panel away from the backlight module.

With reference to the first aspect, in one possible implementation manner, the liquid crystal display device is a mobile terminal.

Alternatively, the liquid crystal display device may be a mobile terminal having a screen ratio of more than 90%.

In a second aspect, there is provided a liquid crystal display device comprising: the backlight module is positioned between the liquid crystal panel and the fingerprint module, and the fingerprint module is used for receiving light reflected by a finger of a user; the backlight module includes: the backlight module comprises a light guide plate and a light source, wherein the light guide plate comprises a light-emitting surface, a backlight surface and a side surface, the light-emitting surface and the backlight surface are oppositely arranged, and the side surface is connected with the light-emitting surface and the backlight surface; a light source adjacent to the side surface of the light guide plate; the prism sheet is arranged on one side of the light emergent surface of the light guide plate; the prism sheet comprises a substrate with uniform thickness and a plurality of prism microstructures protruding from the substrate, the prism microstructures are opposite to the light guide plate, the cross section of each prism microstructure is triangular, and the distance between every two adjacent prism microstructures in the prism microstructures is 0.

In the embodiment of the application, the fingerprint module among the liquid crystal display device can receive the light that the user pointed the reflection, and liquid crystal display device can utilize the light that the finger reflected to come to gather and discern the user fingerprint like this, can realize fingerprint identification under the optical screen. Adopt the anti-prism piece in backlight unit, both can strengthen liquid crystal display panel's luminance, after the light of fingerprint reflection passed the anti-prism piece, it is little to the divergence degree of reverberation, and fingerprint module can gather more clear fingerprint image, improves the fingerprint identification precision.

With reference to the second aspect, in one possible implementation manner, the cross-sectional shape of the prism microstructure is a triangle with an apex angle in a range of 60 ° to 70 °.

With reference to the second aspect, in a possible implementation manner, the fingerprint module includes an infrared transmitter-receiver configured to transmit infrared rays to one side of the liquid crystal panel and receive infrared rays reflected by a finger of a user.

With reference to the second aspect, in a possible implementation manner, the backlight module further includes at least one diffusion sheet and a reflection sheet, the at least one diffusion sheet is located between the light guide plate and the at least one prism sheet, and the reflection sheet is located on the backlight surface side of the light guide plate.

With reference to the second aspect, in a possible implementation manner, the liquid crystal display device further includes a cover glass, and the cover glass is disposed on a side of the liquid crystal panel away from the backlight module.

With reference to the second aspect, in one possible implementation manner, the liquid crystal display device is a mobile terminal.

In a third aspect, a backlight module is provided, which includes: the backlight module comprises a light guide plate and a light source, wherein the light guide plate comprises a light-emitting surface, a backlight surface and a side surface, the light-emitting surface and the backlight surface are oppositely arranged, and the side surface is connected with the light-emitting surface and the backlight surface; a light source adjacent to the side surface of the light guide plate; the prism sheet is arranged on one side of the light emergent surface of the light guide plate; the prism sheet comprises a substrate with uniform thickness and a plurality of prism microstructures protruding from the substrate, wherein each prism microstructure comprises a transmission plane parallel to the substrate, and/or a preset distance is reserved between two adjacent prism microstructures in the prism microstructures.

With reference to the third aspect, in one possible implementation manner, the width of the transmission plane is greater than 0 and less than or equal to 6 micrometers.

With reference to the third aspect, in one possible implementation manner, the preset pitch is greater than 0 and less than or equal to 6 micrometers.

With reference to the third aspect, in a possible implementation manner, in a case that the prism microstructure includes a transmission plane parallel to the substrate, the prism microstructure further includes a plurality of inclined planes and/or arc planes intersecting with the substrate, and the transmission plane connects two adjacent planes of the plurality of inclined planes and/or arc planes.

With reference to the third aspect, in a possible implementation manner, in a case that a preset pitch exists between two adjacent prism microstructures in the plurality of prism microstructures, a cross-sectional shape of each prism microstructure is any one of a triangle, a trapezoid and a semicircle.

With reference to the third aspect, in a possible implementation manner, the prism sheet is a forward prism sheet, and the prism microstructures are disposed opposite to the liquid crystal panel.

With reference to the third aspect, in a possible implementation manner, the cross-sectional shape of the prism microstructure is an isosceles trapezoid, and a base angle of the isosceles trapezoid is 45 °.

With reference to the third aspect, in a possible implementation manner, the prism sheet is an inverse prism sheet, and the prism microstructures are disposed opposite to the light guide plate.

With reference to the third aspect, in one possible implementation manner, the cross-sectional shape of the prism microstructure is a triangle, and the vertex angle of the triangle is 60 ° to 70 °.

With reference to the third aspect, in a possible implementation manner, the backlight module further includes at least one diffusion sheet and a reflection sheet, the at least one diffusion sheet is located between the light guide plate and the at least one prism sheet, and the reflection sheet is located on the backlight surface side of the light guide plate.

In a fourth aspect, a backlight module is provided, which includes: the backlight module is positioned between the liquid crystal panel and the fingerprint module, and the fingerprint module is used for receiving light reflected by a finger of a user; the backlight module includes: the backlight module comprises a light guide plate and a light source, wherein the light guide plate comprises a light-emitting surface, a backlight surface and a side surface, the light-emitting surface and the backlight surface are oppositely arranged, and the side surface is connected with the light-emitting surface and the backlight surface; a light source adjacent to the side surface of the light guide plate; the prism sheet is arranged on one side of the light emergent surface of the light guide plate; the prism sheet comprises a substrate with uniform thickness and a plurality of prism microstructures protruding from the substrate, the prism microstructures are opposite to the light guide plate, the cross section of each prism microstructure is triangular, and the distance between every two adjacent prism microstructures in the prism microstructures is 0.

With reference to the fourth aspect, in one possible implementation manner, the cross-sectional shape of the prism microstructure is a triangle with an apex angle in a range of 60 ° to 70 °.

With reference to the fourth aspect, in a possible implementation manner, the backlight module further includes at least one diffusion sheet and a reflection sheet, the at least one diffusion sheet is located between the light guide plate and the at least one prism sheet, and the reflection sheet is located on the backlight surface side of the light guide plate.

In a fifth aspect, a liquid crystal display is provided, which includes a liquid crystal panel and the backlight module in any one of the possible implementations of the third aspect and the third aspect or any one of the possible implementations of the fourth aspect and the fourth aspect.

Drawings

Fig. 1 is a schematic view of a liquid crystal display device according to an embodiment of the present disclosure;

FIG. 2 is a schematic cross-sectional view of the LCD of FIG. 1 taken along line A-A;

fig. 3 is a partial structural schematic view of the prism sheet of fig. 2;

FIG. 4 is a schematic view of an optical path of the prism sheet;

fig. 5 is a partial structural schematic view of the prism sheet of fig. 2;

FIG. 6 is a schematic graph showing the front direction transmittance of the prism sheet provided in the examples of the present application;

FIG. 7 is a schematic view of the prism sheet for beam splitting;

fig. 8 is a schematic structural view of a prism sheet provided in an embodiment of the present application;

fig. 9 is a schematic structural view of another prism sheet provided in an embodiment of the present application;

FIG. 10 is a schematic cross-sectional view of the LCD of FIG. 1 taken along line A-A;

fig. 11 is a schematic structural view of still another prism sheet provided in an embodiment of the present application;

FIG. 12 is a schematic diagram illustrating the light transmission effect of the prism sheet according to an embodiment of the present disclosure;

fig. 13 is a schematic perspective view of a prism sheet according to an embodiment of the present disclosure.

Reference numerals:

10-liquid crystal displays; 101-fingerprint identification area; 110-a backlight module; 111-a light source; 112-a reflector sheet; 113-a light guide plate; 1131, a light emitting surface; 1132-backlight surface; 1133-side; 114-a diffuser sheet; 115-lower prism sheet; 1151-a substrate; 1152-prismatic microstructures; 1152 a-first inclined face; 1152 b-a second inclined surface; 1152 c-transmission plane; 1153-valley; 1154-peak; 116-upper prism sheet; 120-a liquid crystal panel; 130-cover glass; 20-a housing; 30-a camera; 40-an earpiece; 50-fingerprint module.

Detailed Description

The technical solution in the present application will be described below with reference to the accompanying drawings. It is to be understood that the embodiments described are only a few embodiments of the present application and not all embodiments.

In the following, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature.

Further, in the present application, directional terms such as "upper", "lower", "left", "right", "inner", "outer", "horizontal", "vertical", and the like are defined with respect to a schematically placed orientation or position of a component in the drawings, and it is to be understood that these directional terms are relative concepts that are used for descriptive and clarity purposes and not for indicating or implying that a specified orientation of a referenced device or component must have or be constructed and operated in a specified orientation, which may vary accordingly depending on the orientation in which the component is placed in the drawings, and therefore should not be construed as limiting the present application.

It should be noted that the same reference numerals are used to denote the same components or parts in the embodiments of the present application, and for the same or similar components in the embodiments of the present application, only one of the components or parts may be labeled with the reference numeral, and it should be understood that the reference numerals are also applicable to other components or parts that are the same or similar.

Fingerprint identification technology under the screen, also called stealthy fingerprint technology, is that the fingerprint identification is accomplished to the screen below, and need not finger and fingerprint module (fingerprint sensor module) contact. According to the technical principle and the implementation method, the conventional technology for identifying the fingerprints under the screen mainly comprises capacitive type fingerprint identification under the screen, ultrasonic type fingerprint identification under the screen and optical type fingerprint identification under the screen. The first two fingerprint identification technologies still have many problems to be solved due to the technology being not mature enough, face the difficulty of mass production, and are not widely applied at present. In contrast, the optical underscreen fingerprint identification technology is more mature and is the mainstream underscreen fingerprint identification technology at present.

The optical type fingerprint identification under the screen mainly utilizes the refraction and reflection principle of light, emits light to the screen through a light source under the screen, and detects a fingerprint loop by light reflection when a finger is placed on the screen. The optical fingerprint identification technology under the screen has a high requirement on the light transmittance of the screen, and currently, a commonly used display screen mainly includes a Liquid Crystal Display (LCD) (also called a liquid crystal display) and an organic light-emitting diode (OLED), and the display screen of the optical fingerprint identification technology under the screen generally adopts an OLED screen due to the advantages of independent pixel light emission and thinner screen. When a user presses the screen by a finger, the OLED screen emits light to illuminate a finger area, the reflected light illuminating the fingerprint returns to a sensor under the screen through the screen, and finally, a formed image is compared with an image stored in a database for analysis and identification. However, OLED screens suffer from a number of problems, such as the OLED material that produces blue light degrades faster than other colors, resulting in a lower blue output than other colors; water can instantaneously damage the organic materials of the display screen; the OLED screen consumes very much power when displaying an image with a white background (e.g., a document or website); due to the difference of the display of each pixel of the OLED screen on the screen, the aging speed of each position is different, so that the screen burning problem is caused; the LCD screen has the advantages of low cost, long service life, high brightness, good color uniformity, capability of adjusting light and protecting eyes by natural Direct Current (DC), and the like, and can well solve the problems.

But it is difficult to realize the fingerprint recognition under the optical screen by using the LCD screen. This is because the LCD panel cannot self-illuminate, a backlight source and a plurality of optical films need to be additionally provided, and cover glass is usually provided to protect the screen, so that the entire module is thick and the light transmittance is poor. The light that is launched by the fingerprint module (for example fingerprint module, fingerprint identification sensor, infrared emission receiver etc.) will pass the optical film material and the glass of apron of certain thickness and reach the finger, and the luminous intensity that shines the finger has reduced, shines the light of fingerprint after-reflection and returns on the same way again, and the energy of the light that the fingerprint module received is very low for fingerprint identification's the degree of difficulty is very high. The embodiment of the application provides a backlight module and a liquid crystal display, which are applied to a liquid crystal display device and can realize fingerprint identification under a screen.

Fig. 1 shows a schematic diagram of a liquid crystal display device provided in an embodiment of the present application.

The liquid crystal display device referred to in the embodiments of the present application may include a handheld device, an in-vehicle device, a wearable device, a computing device, or other processing device connected to a wireless modem. A subscriber unit, a cellular phone (cellular phone), a smart phone (smart phone), a Personal Digital Assistant (PDA), a tablet computer, a portable computer, a laptop computer (laptop computer), a smart watch (smart watch), a smart bracelet (smart bracelet), a Machine Type Communication (MTC) terminal, a point of sale (POS) terminal, a car computer, and other devices having a display screen may be included. For convenience of understanding, in the embodiments of the present application, a liquid crystal display device is described as an example of a mobile phone.

As shown in fig. 1, the liquid crystal display device 100 includes a liquid crystal display 10 and a housing 20, the housing 20 is formed with an accommodating space, and the liquid crystal display 10 is disposed in the accommodating space of the housing 20 and connected to the housing 20.

The liquid crystal display 10 may be provided on the front surface of the liquid crystal display device 100, may be provided on the back surface of the liquid crystal display device 100, or may be provided on both the front surface and the back surface of the liquid crystal display device 100. The front side of the liquid crystal display device 100 in the embodiment of the present application may refer to a side facing a user when the user uses the liquid crystal display device 100, and the back side of the liquid crystal display device 100 may refer to a side facing away from the user when the user uses the liquid crystal display device 100.

Optionally, the liquid crystal display device 100 further includes a camera 30 for capturing still images or video. The camera 30 may be disposed on an area other than the liquid crystal display 10 on the front and/or rear of the liquid crystal display device 100. When the screen ratio of the liquid crystal display 10 is high, a partial region may be hollowed out of the liquid crystal display 10, the camera 30 may be disposed in the hollowed-out region, the camera 30 may be disposed on an edge protruding from the main body of the liquid crystal display device 100, or may be disposed on a member that is movable or rotatable with respect to the liquid crystal display device 100, for example, the member may be extended, retracted, rotated, or the like from the main body of the liquid crystal display device 100. In some embodiments, the liquid crystal display device 100 may include 1 or N cameras 30, N being a positive integer greater than 1.

Optionally, the liquid crystal display device 100 may further include an earphone 40, also called a receiver, for converting the audio electrical signal into a sound signal. When the liquid crystal display device 100 is used to receive a call or voice information, a voice can be received by placing the receiver 40 close to the human ear. The earpiece 40 may be disposed on an area other than the liquid crystal display 10 on the front or rear surface of the liquid crystal display device 100. When the screen ratio of the liquid crystal display 10 is high, the earpiece 40 may be eliminated and other sound generating structures may be used instead of the earpiece 40, for example, a structure such as an exciter, a piezoelectric ceramic, a magnetic suspension vibrator, etc. may be disposed in the casing 20 to drive the liquid crystal display 10 or drive the casing 20 to vibrate to generate sound.

It is to be understood that the illustrated structure of the embodiments of the present application does not constitute a specific limitation to the liquid crystal display device 100. In other embodiments of the present application, the liquid crystal display device 100 may include more or less components than those shown, for example, the liquid crystal display device 100 may further include a battery, a flash lamp, a sensor, a memory, etc., or the liquid crystal display device 100 may be provided with different component arrangements than those shown, and the embodiments of the present application are not described in detail.

The liquid crystal display device 100 provided by the embodiment of the application adopts an optical fingerprint identification technology, has a function of fingerprint identification under a screen, and can collect fingerprints by a fingerprint module (not shown in the figure) arranged at the inner side of the liquid crystal display 10 when a user touches or presses the liquid crystal display 10, and completes fingerprint identification.

Alternatively, the liquid crystal display 10 is provided with a fingerprint identification area 101, and when the user places a finger in the fingerprint identification area 101, the liquid crystal display device 100 may perform a fingerprint identification operation for the user. The fingerprint identification area 101 may be a part of the liquid crystal display 10 or may be the whole of the liquid crystal display 10, that is, a user may perform fingerprint identification by placing a finger at any position of the liquid crystal display 10.

Fig. 2 shows a schematic cross-sectional view of the liquid crystal display 10 of fig. 1 along the sectional line a-a.

As shown in fig. 2, a Liquid Crystal Display (LCD)10 includes a backlight module 110, a liquid crystal panel 120, and a cover glass 130, wherein the backlight module 110 includes a light source 111, a reflective sheet 112, a light guide plate 113, a diffusion sheet 114, a lower prism sheet 115, and an upper prism sheet 116.

In the embodiment of the present application, the backlight module (back light module)110 is taken as a side-light type backlight module for convenience of description, and for convenience of description, the illuminating direction parallel to the backlight module 110 is defined as a Z-axis, the advancing direction parallel to the light emitted from the light source 111 is defined as an X-axis, and the direction perpendicular to the X-axis and the Z-axis is defined as a Y-axis. Generally, the illumination direction of the backlight module 110 may also be referred to as a front view direction or a front view angle, which is perpendicular to the display interface of the liquid crystal display 10, so that the proceeding direction of the light emitted from the light source 111 can be understood as being parallel to the display interface of the liquid crystal display 10. In addition, in the embodiment of the present application, the horizontal direction in the drawing, the vertical direction in the drawing, the side close to the user's finger may be expressed as "up", and the side far from the user's finger may be expressed as "down".

The liquid crystal panel (LCD panel)120 of the liquid crystal display 10 does not have a light emitting characteristic, and in order to adjust the luminance of the liquid crystal display 10, the liquid crystal display device is provided with a backlight module 110 for providing a surface light source to the liquid crystal panel 120, so as to provide a light beam with sufficient luminance and uniform distribution to the liquid crystal panel 120.

The backlight module 110 is an edge-type backlight module, and a light source (backlight)111 in the backlight module 110 is disposed at a side surface of the light guide plate 113 to emit light into the light guide plate 113 from the side surface of the light guide plate 113. The light source 111 may be any one of Electroluminescence (EL), Cold Cathode Fluorescent Lamp (CCFL), Light Emitting Diode (LED), cathode emission lamp, tungsten halogen lamp, metal halide lamp, and the like.

Alternatively, the light sources 111 may be arranged in a single-sided type, a double-sided type, a three-sided type, a four-sided type, etc., wherein the light sources 111 are arranged on one side of the light guide plate 130, the light sources 111 are arranged on two sides of the light guide plate 130, the light sources 111 are arranged on three sides of the light guide plate 130, and so on.

The light source 111 provides a line light source or a point light source for the liquid crystal panel 120, and the Light Guide Plate (LGP) 113 is used for receiving light emitted by the light source 111, converting the line light source or the point light source emitted by the light source 111 into a surface light source and guiding the surface light source out, so as to improve light luminance and control brightness uniformity. Specifically, the light guide plate 113 includes a light exit surface 1131 and a backlight surface 1132 which are oppositely arranged in the Z-axis direction, and a side surface 1133 which connects the light exit surface 1131 and the backlight surface 1132, and the light exit surface 1131 is located above the backlight surface 1132. The light source 111 is adjacent to the side surface 1133 of the light guide plate 113, and faces the side surface 1133 to emit light toward the light guide plate 113. The refractive index of the light guide plate 113 is greater than that of air, and when the light emitted from the light source 111 is emitted from the light guide plate 113 to the boundary (i.e., the light emitting surface 1131 and the backlight surface 1132), and the incident angle of the light is greater than a certain angle, the light no longer has a refractive component, but is totally reflected back into the light guide plate 113, so that most of the light emitted from the light source 111 is transmitted by total reflection in the light guide plate 113. In order to form a surface light source, scattering dots (also called dimming dots) are disposed on the backlight surface 1132 of the light guide plate 113, and are used to destroy the total reflection of the light in the light guide plate 113, scatter the light and refract the light out of the light guide plate 113, so that the light emitted from the light emitting surface 1131 of the light guide plate 113 forms a surface light source.

The light guide plate 113 may be a flat plate light guide plate or a wedge light guide plate, wherein the flat plate light guide plate has uniform thickness and simple process, and can be used in a smaller-sized liquid crystal display.

Optionally, the backlight module 110 further includes a lamp reflector (not shown) for reflecting the light emitted from the light source 111 into the light guide plate 113 to improve the utilization rate of the light.

The reflective sheet 112 is provided on the backlight surface 1132 side of the light guide plate 113. Specifically, the reflector (reflector)112 is located below the light guide plate 113, and an upper surface of the reflector is opposite to the backlight surface 1132 of the light guide plate 113, and is used for reflecting the light transmitted from the backlight surface 1132 of the light guide plate 113 back to the inside of the light guide plate 113, so as to prevent the light from leaking outside and improve the light utilization rate. The reflection manner of the reflection sheet 112 may be specular reflection or curved surface reflection. The reflective sheet 112 may be a white reflective sheet.

The diffusion sheet 114 and at least one prism sheet are sequentially stacked on the light exit surface 1131 of the light guide plate 113.

The diffusion sheet 114 is located between the light guide plate 113 and at least one prism sheet, specifically, the diffusion sheet (diffuser)114 is located above the light guide plate 113, and the lower surface of the diffusion sheet (diffuser)114 is opposite to the light exit surface 1131 of the light guide plate 113, and a diffusion layer composed of a plurality of granular objects is provided inside the diffusion sheet 114, which can diffuse the light guided out by the light guide plate 113 to ensure the uniformity of the light distribution.

For example, the backlight module 110 may include a lower diffusion sheet and an upper diffusion sheet, wherein the lower diffusion sheet is located above the light guide plate 113, the lower surface of the lower diffusion sheet is opposite to the light exit surface 1131 of the light guide plate 113, and the upper diffusion sheet is located above the upper prism sheet 116, and the lower surface of the upper diffusion sheet is opposite to the upper surface of the upper prism sheet 116. The upper diffusion sheet is positioned above the prism sheet and can also play a role in protecting the prism sheet.

The prism sheet, which may also be called a brightness enhancement sheet, a brightness enhancement film, or a brightness enhancement film, is disposed between the diffusion sheet 114 and the liquid crystal panel 120, and is used to improve the angular distribution of light, so that the light emitted from the diffusion sheet 114 and uniformly diffused at various angles (the light has poor directivity) can be concentrated in the normal direction (i.e., the front view direction) of the display screen of the liquid crystal display 10 by refraction and reflection of light, thereby enhancing the front light intensity without increasing the total emergent light flux, and increasing the use efficiency of the light emitted from the diffusion sheet 114.

One or more prism sheets may be provided in the embodiments of the present application, and the prism sheets are exemplarily shown to include a lower prism sheet 115 and an upper prism sheet 116. The lower prism sheet 115 is positioned above the diffusion sheet 114, and the lower surface thereof is opposite to the upper surface of the diffusion sheet 114, and the upper prism sheet 116 is positioned above the lower prism sheet 115, and the lower surface thereof is opposite to the upper surface of the lower prism sheet 115. The lower prism sheet 115 and the upper prism sheet 116 may correct the angle at which light transmitted through the diffusion sheet 114 is diffused, and concentrate light emitted from the diffusion sheet 114 at various angles to an angle perpendicular to the liquid crystal display 10, thereby enhancing the brightness of the display screen.

The lower prism sheet 115 includes a substrate 1151 and a plurality of bar-shaped prism microstructures 1152 formed on the substrate 1151, the substrate 1151 has a uniform thickness, the prism microstructures 1152 have a trapezoidal cross-sectional shape, and the plurality of prism microstructures 1152 are spaced apart in parallel to each other and are opposite to the lower surface of the upper prism sheet 116 (or on the side close to the user's finger). The prism microstructures 1152 have a light-gathering function, so that the backlight module 110 emits light with strong directional directivity.

Referring to fig. 3, fig. 3 illustrates a partial structural schematic view of the lower prism sheet 115 of fig. 2. As shown in fig. 3, the prism microstructure 1152 includes a first inclined surface 1152a, a second inclined surface 1152b, and a transmission plane 1152c connecting the first inclined surface 1152a and the second inclined surface 1152b, the transmission plane 1152c being a top surface of the prism microstructure. The angle between the first inclined surface 1152a and the base 1151 is an acute angle or a right angle, and the angle between the second inclined surface 1152b and the base 1151 is an acute angle or a right angle, but it should be understood that the angle between the first inclined surface 1152a and the base 1151 is not the same as the angle between the second inclined surface 1152b and the base 1151. The transmission plane 1152c is a plane and is parallel to the substrate 1151. The plurality of prism microstructures 1152 includes a plurality of first inclined surfaces 1152a and a plurality of second inclined surfaces 1152b, and the plurality of first inclined surfaces 1152a and the plurality of second inclined surfaces 1152b may be alternately arranged in a horizontal direction. Between two adjacent prism microstructures 1152, the first inclined surface 1152a of one of the prism microstructures 1152 intersects with the second inclined surface 1152b of the other prism microstructure 1152, forming a valley 1153 of the lower prism sheet 115.

Alternatively, the cross-sectional shape of the prismatic microstructure 1152 is an isosceles trapezoid.

Alternatively, for the same prismatic microstructure 1152, the angle formed by the first inclined surface 1152a and the second inclined surface 1152b in the extension line direction is 60 ° to 140 °. Preferably, the angle formed by the first inclined surface 1152a and the second inclined surface 1152b in the extension line direction is 90 °. In other words, if the cross-sectional shape of the prism microstructure is an isosceles trapezoid, the base angle of the isosceles trapezoid may be 45 °. The bottom angle of the trapezoid should be understood as the angle between the first inclined surface 1152a and the base 1151, and the angle between the second inclined surface 1152b and the base 1151.

Still referring to fig. 2, the structures of the upper prism sheet 116 and the lower prism sheet 115 may be identical, that is, the upper prism sheet 116 includes a plurality of prism microstructures 1162 formed on a substrate 1161, the thickness of the substrate 1161 is uniform, and the cross-sectional shape of the prism microstructures 1162 is trapezoidal. The shapes of the

prism microstructures

1162 and 1152 can be the same, and reference may be specifically made to fig. 3 and the description related to fig. 3, which is not repeated here.

In the embodiment of the present application, the upper prism sheet 116 is located above the lower prism sheet 115, the substrate 1161 of the upper prism sheet 116 is opposite to the prism microstructures 1152 of the lower prism sheet 115, and an included angle between the extending direction of the prism microstructures 1162 of the upper prism sheet 116 and the extending direction of the prism microstructures 1152 of the lower prism sheet 115 is not 0 °. In other words, the prism microstructures 1152 of the lower prism sheet 115 have a first extending direction, the prism microstructures 1162 of the upper prism sheet 116 have a second extending direction, and an included angle between the first extending direction and the second extending direction is not 0. Fig. 2 exemplarily shows that the first extending direction and the second extending direction form an angle of 90 °, and the upper prism sheet 116 is equivalent to that obtained by rotating the lower prism sheet 115 by 90 ° around the Z-axis. The prism microstructures 1152 of the prism sheet 115 have a trapezoidal cross-section in the XZ plane, and the prism microstructures 1162 of the prism sheet 116 have a trapezoidal cross-section in the YZ plane. It should be understood that the

prism microstructures

1152 and 1162 have a trapezoidal cross section, and the bar-shaped

prism microstructures

1152 and 1162 have prisms, so that the first extending direction of the prism microstructure 1152 and the second extending direction of the prism microstructure 1162 can be understood as the length direction of the prisms.

Optionally, an included angle between the extending direction of the prism microstructures 1162 of the upper prism sheet 116 and the extending direction of the prism microstructures 1152 of the lower prism sheet 115 is 90 °, that is, an included angle between the first extending direction and the second extending direction is 90 °. In the backlight module 110, the strip-shaped prism microstructures of the lower prism sheet 115 and the upper prism sheet 116 are vertically arranged, so that the light rays emitted by the backlight module 110 on the XZ plane and the YZ plane have certain directional constraint. Taking fig. 2 as an example, the prism microstructures 1152 of the lower prism sheet 115 extend parallel to the Y axis, the lower prism sheet 115 has a converging effect on light rays on the XZ plane, the prism microstructures 1162 of the upper prism sheet 116 extends parallel to the X axis, and the upper prism sheet 116 has a converging effect on light rays on the YZ plane, so that light rays emitted by the backlight module 110 along all directions have strong directivity. And the light which does not meet a certain emergent direction can be reflected back to the reflector plate 112 through the prism microstructure and can be reused after being reflected by the reflector plate 112, so that the utilization rate of the backlight is improved.

In some embodiments, the backlight module 110 further includes an outer frame, such as a plastic frame (plastic frame) or an iron frame, for fixing the whole backlight module 110, so as to prevent damage and influence of improper collision and dirt on the backlight module 110.

As described above with respect to the backlight module 110, the backlight module 110 is located behind the liquid crystal panel 120, and referring to fig. 2, the liquid crystal panel 120 is located above the backlight module 110.

Optionally, a cover glass 130 may be further disposed above the liquid crystal panel 120 in order to protect the liquid crystal panel 120.

In the embodiment of the present application, the liquid crystal display device 100 in fig. 1 further includes a fingerprint module 50 for receiving the light reflected by the finger of the user and collecting and identifying the fingerprint of the user, the fingerprint module 50 is located behind the backlight module 110, that is, the fingerprint module 50 is located below the backlight module 110, specifically, the fingerprint module 50 is located below the reflector plate 112. Backlight unit 110 is located between liquid crystal panel 120 and the fingerprint module 50 like this, and the fingerprint identification area 101 that is shown in fig. 1 and fig. 2 corresponds the position that fingerprint module 50 is located promptly.

Thus, when the finger of the user is located in the fingerprint identification area 101, the light emitted from the fingerprint module 50, such as infrared light, can be emitted to the outside through the backlight module 110, the liquid crystal panel 120 and the cover glass 130. Light emitted to the outside is incident on a finger and is reflected into the inside of the cover glass 130 via the finger, and specifically, the light incident on the finger is incident from the ridge of the fingerprint contacting the cover glass 130 to the inside of the cover glass 130, or is re-incident from the valley of the fingerprint not contacting the cover glass 130 to the inside of the cover glass 130 through the air interposed between the skin of the finger and the cover glass 130. The light reflected by the finger then passes through the cover glass 130, the liquid crystal panel 120 and the backlight module 110 in sequence, and reaches the fingerprint module 50. The fingerprint module 50 can capture a fingerprint image and convert the captured image into an electric signal, identifies and verifies the fingerprint of a user, and allows the user to operate the liquid crystal display device after the fingerprint passes verification, so that the liquid crystal display device is prevented from being operated by a stranger, and the safety of the liquid crystal display device is ensured.

In some embodiments, the fingerprint module 50 may include a plurality of sub-modules, such as a fingerprint collection sub-module, a fingerprint identification sub-module, an extended function sub-module, and the like, each of which is used to implement a part of the functions of the fingerprint module 50.

It should be understood that, in the embodiment of the present application, the specific structure of the backlight module 110 is not limited to the above structure, and in practical applications, the specific structure may also be adjusted appropriately according to different products, and the embodiments of the present application are not described in detail.

In the embodiment of the present application, the cross-sectional shape of the prism microstructure of the prism sheet adopted in the backlight module 110 is trapezoidal, the light emitted from the fingerprint module 50 passes through the prism sheet, part of the light is refracted and reflected by the inclined plane of the prism sheet, and part of the light can be directly emitted through the transmission plane of the prism sheet, so that the transmittance of the prism sheet for emitting light in the front view direction can be improved, therefore, the light reaching the finger of the user can be enhanced, further, when the light returns to the fingerprint module 50 in the original way, the prism sheet with the structure can enhance the energy of the light reaching the fingerprint module 50, and the fingerprint identification precision can be improved.

Specifically, referring to fig. 4, (a), (b), and (c) in fig. 4 are schematic diagrams of optical paths when the cross-sectional shape of the conventional prism microstructure is triangular, and (d) is a schematic diagram of optical paths when the cross-sectional shape of the prism microstructure of the embodiment of the present application is trapezoidal. In fig. 4 (a), the cross section of the prism microstructure is triangular, and the vertex angle C is an obtuse angle, and it can be seen from the figure that after light vertically enters the prism microstructure from the side of the bottom edge opposite to the vertex angle C (i.e. from the side of the base of the prism sheet), the light is reflected back to the incident side of the light after being reflected by the two inclined surfaces; in fig. 4 (b), the cross section of the prism microstructure is triangular, and the vertex angle C is a right angle, and it can be seen from the figure that after light vertically enters the prism microstructure from the side of the bottom edge opposite to the vertex angle C (i.e. from the side of the base of the prism sheet), the light is reflected vertically back to the incident side after being reflected by the two inclined surfaces; in (C) of fig. 4, the cross section of the prism microstructure is triangular, and the vertex angle C is an acute angle, and it can be seen from the figure that after light vertically enters the prism microstructure from the bottom side opposite to the vertex angle C (i.e. from the substrate side of the prism sheet), the light can be refracted out of the prism microstructure after being reflected by two inclined planes, but just because the prism sheet can converge the light emitted from the light guide plate, the light reflected by a finger can become divergent after passing through the prism microstructure of the prism sheet, so that the fingerprint module can hardly collect a clear fingerprint image, and the situation can also occur when the vertex angle C is an obtuse angle and a right angle. Therefore, when the cross-sectional shape of the prism microstructure of the prism sheet is triangular, most of the light rays emitted from the fingerprint module can be reflected back to the diffusion sheet and the light guide plate when passing through the prism sheet, and then are recycled after being reflected by the reflection sheet, so that the light rays reaching the finger are reduced, the light rays return back to the original path, and the light rays reaching the fingerprint module are fewer. In addition, when the light that the finger reflects passed the prism piece, light can become to disperse, causes the fingerprint image of fingerprint module collection not clear like this, and the discernment degree of difficulty is high. Fig. 4 (d) is a cross-sectional shape of the prism microstructure of the prism sheet according to the embodiment of the present application, where the cross-sectional shape is trapezoidal, and it can be seen from the figure that the trapezoidal transmission plane can directly transmit the light, so that the light rays in the middle of the light rays entering the prism sheet from one side of the fingerprint module can exit the prism sheet through the trapezoidal transmission plane, thereby improving the transmittance of the light rays exiting at one time in the front view, and further increasing the light quantity reaching the finger, and the light energy received by the fingerprint module can also be correspondingly increased, thereby improving the fingerprint identification capability. In addition, can directly jet out the prism piece after the partial light that reflects back backlight unit from the finger passes trapezoidal transmission plane, reduced the light that is dispersed by the inclined plane of prism microstructure to can increase the energy of the light that reaches the fingerprint module, make the fingerprint module can gather clear fingerprint image.

The following prism sheet 115 is taken as an example, and the specific structure of the prism micro-structure 1152 of the prism sheet 115 is described below with reference to fig. 5. As shown in fig. 5, the prism microstructures 1152 have a trapezoidal cross-section, and the width B of the transmission plane 1152c connecting the first inclined surface 1152a and the second inclined surface 1152B determines the transmittance of the lower prism sheet 115 in the front view direction. Alternatively, the width B of the transmissive plane 1152c may be a positive number less than or equal to 6 microns. The height H of the prism microstructures 1152 in the shape of a trapezoid can be determined according to the width B of the transmission plane 1152c and the inclination angles of the first inclined plane 1152a and the second inclined plane 1152B, wherein the inclination angles of the first inclined plane 1152a and the second inclined plane 1152B can be determined according to the light condensing capability of the prism sheet on the light emitted from the diffuser sheet.

Fig. 6 is a schematic graph showing the front direction transmittance of the prism sheet when different parameters are used for the prism microstructures. As shown in the figure, curve P1 represents the relationship curve between the light transmittance and the light wavelength of the prism sheet when the cross-sectional shape of the prism microstructure is triangular; a curve P2 shows a relationship between the light transmittance and the wavelength of light of the prism sheet when the cross-sectional shape of the prism microstructure is trapezoidal and the width B of the transmission plane of the prism microstructure is 3 μm; curve P3 shows the relationship between the light transmittance and the wavelength of light of the prism sheet when the cross-sectional shape of the prism microstructure is trapezoidal and the width B of the transmission plane of the prism microstructure is 6 μm. It can be seen that the light transmittance of the prism sheet is higher when the prism microstructures of the prism sheet have a trapezoidal sectional shape than when the prism microstructures have a triangular sectional shape. When the cross-sectional shape of the prism microstructures of the prism sheet is a trapezoid, the larger the width B of the transmission plane of the prism microstructures in a certain range, the higher the light transmittance of the prism sheet.

In addition, the prism sheet has a light splitting function, as shown in fig. 7, an image D1 is separated after passing through the prism sheet, and two images D2 and D3 are formed, wherein the two images D2 and D3 have the same shape as the image D1, but the resolution is reduced due to refraction of two inclined surfaces of the prism microstructure of the prism sheet. The prism sheet has trapezoidal cross section, and can reduce image separation effect and raise image resolution.

The transmission plane 1152c shown in fig. 3 or 5 described above is parallel to the substrate 1151, and it can be understood that a light-transmitting region is formed. The light may be directly transmitted out of the prism sheet when being incident to the light transmission region. While the prismatic microstructures described above have a trapezoidal cross-sectional shape, such as the prismatic microstructures 1152 shown in fig. 3 or 5 having two tilted surfaces connected by a transmission plane 1152c, in other embodiments of the present disclosure, the prismatic microstructures 1152 may include a transmission plane parallel to the substrate 1151 and a plurality of tilted surfaces and/or curved surfaces intersecting the substrate 1151, the transmission plane connecting two adjacent surfaces of the plurality of tilted surfaces and/or curved surfaces. For example, the prism microstructure includes a plurality of inclined planes, and the transmission plane connects two adjacent planes of the plurality of inclined planes, that is, the cross-sectional shape of the prism microstructure is a polygon. For another example, the prism microstructure includes a plurality of curved surfaces, and the transmission plane connects two adjacent surfaces of the plurality of curved surfaces, that is, the cross-sectional shape of the prism microstructure is drum-shaped. For another example, the prism microstructure includes at least one inclined surface and at least one arc surface, and the transmission plane connects two adjacent surfaces, that is, the cross-sectional shape of the prism microstructure is a pattern enclosed by a straight line and an arc line.

The prism sheet with the trapezoidal cross section of the prism microstructure described above can improve the transmittance of light emitted once in the front view direction, and to achieve this effect, the prism sheet in the embodiment of the present application may also adopt the structure shown in fig. 8. Referring to fig. 8, taking the lower prism sheet 115 as an example, the lower prism sheet 115 includes a substrate 1151 and a plurality of bar-shaped prism microstructures 1152 formed on the substrate 1151, the thickness of the substrate 1151 is uniform, the cross-sectional shape of the prism microstructures 1152 is triangular, and the plurality of prism microstructures 1152 are separated in a parallel manner with each other. Specifically, the prism microstructures 1152 includes a first inclined surface 1152a and a second inclined surface 1152b, and the first inclined surface 1152a and the second inclined surface 1152b intersect to form a peak 1154 of the lower prism sheet 115. Two adjacent prism microstructures 1152 have a predetermined distance therebetween, that is, a first inclined surface 1152a of one of the prism microstructures 1152 is connected to a second inclined surface 1152b of the other prism microstructure 1152 by a plane, so as to form a valley 1153 of the lower prism sheet 115, and the valley 1153 of the lower prism sheet 115 has a certain width.

The cross-sectional shape of the prism microstructures of the prism sheet in the embodiment of the present application may be other shapes, and still take the prism sheet 115 as an example, for example, as shown in fig. 9 (a), the cross-sectional shape of the prism microstructures 1152 of the prism sheet 115 is a trapezoid, and a valley 1153 formed between two adjacent prism microstructures has a certain width; or as shown in fig. 9 (b), the cross-sectional shape of the prismatic microstructure 1152 is an arc or a semicircle, and a valley 1153 formed between two adjacent prismatic microstructures has a certain width; or as shown in fig. 9 (c), the cross-sectional shape of the prismatic microstructure 1152 includes two inclined planes and an arc connecting the two inclined planes, and a valley 1153 formed between two adjacent prismatic microstructures has a certain width; also alternatively, as shown in (d) of fig. 9, the cross-sectional shape of the prism microstructure 1152 includes two inclined planes and a plane connecting the two inclined planes, the plane forming an angle other than 0 ° with the substrate 1151, and a valley 1153 formed between adjacent two prism microstructures has a certain width, and so on. Because the two adjacent prism microstructures 1152 have a preset distance therebetween, when the prism sheet with the prism microstructures is applied to the backlight module 110, the transmittance of primary light emission in the front view direction can be enhanced, so that the energy of light received by the fingerprint module can be enhanced, and the fingerprint identification precision is improved.

It should be understood that the prism microstructures may be arranged at equal intervals, so that the preset intervals between the prism microstructures are the same; the prismatic microstructures may also be arranged at different pitches such that the predetermined pitches between the prismatic microstructures are different.

The embodiment of the present application further provides another liquid crystal display 10 and a backlight module 110. Fig. 10 shows a schematic cross-sectional view of the liquid crystal display 10 of fig. 1 taken along the sectional line a-a.

As shown in fig. 10, a Liquid Crystal Display (LCD)10 includes a backlight module 110, a liquid crystal panel 120, and a cover glass 130, wherein the backlight module 110 includes a light source 111, a reflective sheet 112, a light guide plate 113, a diffusion sheet 114, a lower prism sheet 115, and an upper prism sheet 116.

Different from the backlight module 110 shown in fig. 2, the forward prism sheets used for the lower prism sheet 115 and the upper prism sheet 116 in fig. 2, i.e., the prism sheets with the prism microstructures 1152 opposite to the liquid crystal panel 120, and the reverse prism sheets used for the lower prism sheet 115 and the upper prism sheet 116 in fig. 10 (or referred to as reverse prism sheets).

The reverse prism sheet refers to a prism sheet in which prism microstructures are formed under a substrate, and the prism microstructures 1152 are opposite to the light guide plate 113. Specifically, the lower prism sheet 115 is positioned above the diffusion sheet 114, and the lower surface thereof is opposite to the upper surface of the diffusion sheet 114, and the upper prism sheet 116 is positioned above the lower prism sheet 115, and the lower surface thereof is opposite to the upper surface of the lower prism sheet 115. In the embodiment of the present application, the structures of the lower prism sheet 115 and the upper prism sheet 116 may be the same, and only the prism sheet 115 is described below as an example.

The lower prism sheet 115 includes a base 1151 and a plurality of bar-shaped prism microstructures 1152 formed on the base 1151, the base 1151 has a uniform thickness, the prism microstructures 1152 have a triangular cross-sectional shape, and the plurality of prism microstructures 1152 are spaced apart in parallel with each other and are opposite to the upper surface of the diffusion sheet 114 (or on the side facing away from the user's fingers).

Referring to fig. 11, fig. 11 illustrates a partial structural schematic view of the lower prism sheet 115 of fig. 10. As shown in fig. 11 (a), the prismatic microstructure 1152 includes a first inclined surface 1152a and a second inclined surface 1152 b. For the same prism microstructure 1152, the first inclined surface 1152a and the second inclined surface 1152b intersect to form a peak 1154 of the lower prism sheet 115, and for two adjacent prism microstructures, the first inclined surface 1152a of one prism microstructure intersects with the second inclined surface 1152b of the other prism microstructure to form a valley 1153 of the lower prism sheet 115. The angle between the first inclined surface 1152a and the base 1151 is an acute angle or a right angle, and the angle between the second inclined surface 1152b and the base 1151 is an acute angle or a right angle.

Alternatively, the cross-sectional shape of the prismatic microstructure 1152 is an isosceles triangle.

Alternatively, the triangular cross section of the prismatic microstructure 1152 has a vertex angle of 60 ° to 70 °, that is, for the same prismatic microstructure 1152, an angle formed by the first inclined surface 1152a and the second inclined surface 1152b in the extending direction is 60 ° to 70 °. Preferably, the first inclined surface 1152a forms an angle with the second inclined surface 1152b in the extension line direction of 68 °.

In the embodiments of the present application, the prism microstructures are periodically formed to have a constant pitch parallel to each other, the constant pitch being greater than or equal to 0. That is, the pitch between two adjacent prism microstructures 1152 may be 0, or may be greater than 0. As shown in (b) of fig. 11, the valley 1153 between two adjacent prism microstructures has a certain width, and when there is a preset distance between two adjacent prism microstructures, a person skilled in the art can determine the size of the preset distance according to actual needs. Optionally, the distance between two adjacent prism microstructures is 0-6 microns.

Fig. 12 shows a schematic diagram of the light transmission effect of prism microstructures having different pitches. The front receiver in the figure can be understood as the glass cover 130 and the back receiver can be understood as the fingerprint module 50. It can be seen from the figure that as the spacing between two adjacent prism microstructures is increased, the brightness curve of the front receiver has little change, and the gain at the center point is slightly reduced, but the brightness curve of the rear receiver has obvious change, and the gain at the center point is obviously improved. Therefore, in a certain range, for example, when the distance between two adjacent prism microstructures is 0-6 micrometers, the light energy received by the fingerprint module is also enhanced along with the increase of the distance between the two prism microstructures.

The prism microstructures of the prism sheet described above are in a strip shape, as shown in (a), (c) in fig. 13, in some embodiments, the prism microstructures in the present embodiment may be in a quadrangular prism shape, as shown in (b) in fig. 13, a plurality of quadrangular prism microstructures are formed on a substrate of the prism sheet, the prism microstructures are arranged in both the transverse direction and the longitudinal direction of the substrate at an elevation angle, and a distance between two adjacent prism microstructures is greater than or equal to 0.

It should be noted that above-mentioned fingerprint module 50 can be to liquid crystal display panel 120 side transmission infrared light and receive the infrared light of reflection through the finger, in other some embodiments of this application, a light source for shining the finger can separately set up with fingerprint module 50, fingerprint module 50 can only be used for receiving the light of reflection through the finger like this, and liquid crystal display device can utilize the light of reflection of finger to come to gather and discern user's fingerprint like this, also can realize fingerprint identification under the optical screen. In other embodiments of the present application, the light used to illuminate the finger is not limited to infrared light, but may be light of other wavelengths, such as visible light or near-infrared light.

In the description of the present application, it should be noted that, unless otherwise explicitly stated or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; either directly or indirectly through intervening media, or may be interconnected between two elements. The above terms are specifically understood in the present application by those of ordinary skill in the art.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A liquid crystal display device, comprising: a liquid crystal panel, a backlight module and a fingerprint module,

the backlight module is positioned between the liquid crystal panel and the fingerprint module, and the fingerprint module is used for receiving light reflected by a finger of a user;

the backlight module includes:

the backlight module comprises a light guide plate and a light source, wherein the light guide plate comprises a light-emitting surface, a backlight surface and a side surface, the light-emitting surface and the backlight surface are oppositely arranged, and the side surface is connected with the light-emitting surface and the backlight surface;

a light source adjacent to the side surface of the light guide plate;

the prism sheet is arranged on one side of the light emergent surface of the light guide plate;

the prism sheet comprises a substrate with uniform thickness and a plurality of prism microstructures protruding from the substrate, wherein each prism microstructure comprises a transmission plane parallel to the substrate, and/or a preset distance is reserved between two adjacent prism microstructures in the prism microstructures.

2. The liquid crystal display device according to claim 1, wherein the width of the transmission plane is greater than 0 and less than or equal to 6 μm.

3. The lcd device of claim 1 or 2, wherein the predetermined pitch is greater than 0 and less than or equal to 6 μm.

4. The liquid crystal display device according to any one of claims 1 to 3, wherein in a case where the prism microstructure includes a transmission plane parallel to the substrate,

the prism microstructure further comprises a plurality of inclined planes and/or cambered surfaces intersected with the substrate, and the transmission plane is connected with two adjacent planes in the plurality of inclined planes and/or cambered surfaces.

5. The liquid crystal display device according to any one of claims 1 to 4, wherein, in a case where there is a preset pitch between adjacent two of the plurality of prismatic microstructures,

the cross section of the prism microstructure is any one of a triangle, a trapezoid and a semicircle.

6. The liquid crystal display device according to any one of claims 1 to 5, wherein the prism sheet is a forward prism sheet, and the prism microstructures are disposed opposite to the liquid crystal panel.

7. The liquid crystal display device according to claim 6, wherein the cross-sectional shape of the prism microstructure is an isosceles trapezoid, and a base angle of the isosceles trapezoid is 45 °.

8. The liquid crystal display device according to any one of claims 1 to 5, wherein the prism sheet is an inverse prism sheet, and the prism microstructures are disposed opposite to the light guide plate.

9. The liquid crystal display device according to claim 8, wherein the cross-sectional shape of the prism microstructure is a triangle, and the apex angle of the triangle is 60 ° to 70 °.

10. The liquid crystal display device according to any one of claims 1 to 9, wherein the fingerprint module includes an infrared transmitter-receiver for transmitting infrared rays to a side of the liquid crystal panel and receiving infrared rays reflected by a finger of a user.

11. The lcd apparatus of any one of claims 1 to 10, wherein the backlight module further comprises at least one diffuser sheet and a reflector sheet, the at least one diffuser sheet is located between the light guide plate and the at least one prism sheet, and the reflector sheet is located on the backlight surface side of the light guide plate.

12. The liquid crystal display device according to any one of claims 1 to 11, further comprising a cover glass disposed on a side of the liquid crystal panel facing away from the backlight module.

13. The liquid crystal display device according to any one of claims 1 to 12, wherein the liquid crystal display device is a mobile terminal.

14. A liquid crystal display device, comprising: a liquid crystal panel, a backlight module and a fingerprint module,

the backlight module includes:

a light source adjacent to the side surface of the light guide plate;

the prism sheet comprises a substrate with uniform thickness and a plurality of prism microstructures protruding from the substrate, the prism microstructures are opposite to the light guide plate, the cross section of each prism microstructure is triangular, and the distance between every two adjacent prism microstructures in the prism microstructures is 0.

15. The liquid crystal display device according to claim 14, wherein the cross-sectional shape of the prism microstructure is a triangle having an apex angle of 60 ° to 70 °.

16. The lcd device of claim 14 or 15, wherein the fingerprint module comprises an infrared transmitter-receiver for transmitting infrared rays to one side of the lcd panel and receiving infrared rays reflected by a finger of a user.

17. The lcd apparatus of any one of claims 14 to 16, wherein the backlight module further comprises at least one diffuser sheet and a reflector sheet, the at least one diffuser sheet is located between the light guide plate and the at least one prism sheet, and the reflector sheet is located on the backlight surface side of the light guide plate.

18. The lcd device according to any one of claims 14 to 17, further comprising a cover glass disposed on a side of the lcd panel facing away from the backlight module.

19. The liquid crystal display device according to any one of claims 14 to 18, wherein the liquid crystal display device is a mobile terminal.