WO2021026684A1

WO2021026684A1 - Fingerprint recognition module, in-screen optical fingerprint system, and electronic device

Info

Publication number: WO2021026684A1
Application number: PCT/CN2019/099983
Authority: WO
Inventors: 葛丛; 蔡斐欣
Original assignee: 深圳市汇顶科技股份有限公司
Priority date: 2019-08-09
Filing date: 2019-08-09
Publication date: 2021-02-18
Also published as: CN111095272A; CN111095272B

Abstract

A fingerprint recognition module (3), an in-screen optical fingerprint system, and an electronic device. The fingerprint recognition module (3) is disposed under a display panel (1), and comprises an optical lens group (8), a reflector (9), and a fingerprint recognition chip (10). A reflection surface of the reflector (9) faces an outer side of the display panel (1), and at least a part of the reflection surface of the reflector (9) faces a sensing surface (101) of the fingerprint recognition chip (10). The optical lens group (8) is used to converge light beams reflected by a finger (5) on a surface of the display panel (1) and to form an image on the sensing surface (101). The optical lens group (8) comprises at least one lens (82-83), and the optical axis (O1, O4) of the at least one lens (82-83) on an object side surface and/or the optical axis (O2, O4) of the at least one lens (82-83) on an image side surface have an included angle (θ1, θ3) of less than 90 degrees with respect to a horizontal direction. The invention improves the accuracy of fingerprint recognition.

Description

Fingerprint recognition module, under-screen optical fingerprint system and electronic device

Technical field

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

Background technique

With the development of display technology, identification technology continues to innovate, change and develop, especially fingerprint identification technology in mobile terminals has become the mainstay of identification. With the changes in people's aesthetics, high-to-weight screens have increasingly become mainstream elements. Mobile phones are entering the era of full screens. The under-screen optical fingerprint recognition system combined with full screen design brings users the ultimate visual experience and good user experience.

Optical fingerprint recognition is a method for fingerprint recognition in the display area of the screen based on optical characteristics. The imaging principle of optical fingerprint recognition is that the transmitter emits light onto the finger. The peaks and troughs of the fingerprint cause differences in energy intensity due to different light absorption and reflection capabilities. The receiver at the bottom of the screen can effectively identify the difference in energy and obtain the brightness Different light and dark stripes are fingerprint image information. Specifically, the fingerprint recognition module in the prior art generally includes a lens group composed of at least one lens, a fingerprint recognition chip, etc. The external light source emits infrared light to irradiate the finger on the surface of the display panel, and the fingerprint is detected by reflection on the finger. The light passes through the display panel and is incident on the lens group. The lens group condenses the fingerprint detection light and forms a fingerprint image on the fingerprint recognition chip, so that the fingerprint recognition chip collects and recognizes the fingerprint image.

However, in the aforementioned fingerprint recognition module, the lens group has asymmetrical aberrations during the imaging process, which will interfere with the imaging of the fingerprint image. Therefore, the fingerprint recognition module of the prior art has the problem of low fingerprint recognition accuracy.

Summary of the invention

The invention provides a fingerprint identification module, an under-screen optical fingerprint system and an electronic device to solve the problem of low fingerprint identification accuracy in the prior art.

A first aspect of the present invention provides a fingerprint identification module, which is arranged under the display panel. The fingerprint identification module includes an optical lens group, a reflector, and a fingerprint identification chip. The reflective surface of the reflector faces the outside of the display panel, and At least part of the reflective surface of the reflector faces the sensing surface of the fingerprint recognition chip. The optical lens group is used to converge the light reflected by the finger on the surface of the display panel and form an image on the sensing surface. The optical lens group includes at least one lens, and the The optical axis of the object side surface and/or the optical axis of the image side surface and the horizontal direction have an included angle of less than 90°.

In a specific embodiment of the present invention, the optical lens group further includes an aperture, and the aperture is arranged at the side of at least one lens.

In a specific embodiment of the present invention, the axis of the aperture and the horizontal direction have an included angle less than 90°.

In the specific embodiment of the present invention, the optical lens group includes a first lens and a second lens arranged in sequence from the object side to the image side, the aperture is arranged between the first lens and the second lens, and the fingerprint recognition light passes through the first lens. After the lens, the aperture, and the second lens, they are irradiated onto the reflective surface of the reflector.

In a specific embodiment of the present invention, the optical axis of the object side surface of the first lens is parallel to the horizontal direction.

In a specific embodiment of the present invention, the angle between the optical axis of the image side surface of the first lens and the horizontal direction is θ1, which satisfies 5°<θ1<25°.

In a specific embodiment of the present invention, the focal length of the first lens is f1, and the radius of curvature of the image side surface of the first lens is R2, satisfying: f1/R2>-2; and/or, the refractive index of the first lens n1 satisfies: n1>1.50, and the dispersion coefficient v1 of the first lens satisfies: v1>53.

In the specific embodiment of the present invention, the angle between the axis of the aperture and the horizontal direction is θ2, which satisfies 5°<θ2<25°.

In the specific embodiment of the present invention, the angle between the optical axis of the image side surface and the optical axis of the object side surface of the second lens and the horizontal direction are both θ3, which satisfies 5°<θ3<25°.

In the specific embodiment of the present invention, the focal length of the second lens is f2, the radius of curvature of the object side surface of the second lens is R3, and the radius of curvature of the image side surface of the second lens is R4, which satisfies: 0<f2/R3 <1.5; -2<f2/R4<0; and/or, the refractive index n2 of the second lens satisfies: n2>1.50, and the dispersion coefficient v2 of the second lens satisfies: v2>53.

In a specific embodiment of the present invention, the distance between the reflective surface of the reflector and the lower surface of the display panel is less than 1.7 mm; and/or the overall focal length of the optical lens group is less than 1.2 mm.

In the specific embodiment of the present invention, the angle θ1 between the optical axis of the image side surface of the first lens and the horizontal direction, the angle θ2 between the axis of the diaphragm and the horizontal direction, and the optical axis of the image side surface of the second lens The angle θ3 between the optical axis of the object side surface and the horizontal direction satisfies: θ1=θ2=θ3.

In a specific embodiment of the present invention, the object side surface and/or the image side surface of at least one lens is a rotationally symmetric aspheric surface.

In a specific embodiment of the present invention, in the optical lens group, the object side surface and/or the image side surface of the lens closest to the image side is a rotationally symmetric aspheric surface.

In a specific embodiment of the present invention, the optical lens group further includes an infrared-transmitting filter, and the infrared-transmitting filter is arranged on the side of at least one lens or on the surface of the fingerprint recognition chip to filter out visible light.

In a specific embodiment of the present invention, the infrared-transmitting filter is arranged on the object side surface of the lens closest to the object side in the optical lens group.

In the specific embodiment of the present invention, the reflector and the fingerprint identification chip are arranged at intervals in the thickness direction of the display panel, the fingerprint identification chip is arranged between the reflector and the display panel, and the optical lens group is arranged on the reflector and the fingerprint identification chip The side.

In a specific embodiment of the present invention, the fingerprint recognition module further includes a fixed support, and the reflector, fingerprint recognition chip and optical lens group are all fixed on the fixed support, and the fixed support and the display panel are relatively fixed.

In a specific embodiment of the present invention, the fixed support includes a bottom wall and a side wall, the fingerprint identification chip is arranged on the bottom wall, the side wall is arranged around the outer side of the fingerprint identification chip, and the side wall is provided with a fingerprint detection light for passing through The optical lens group is arranged on the side of the opening, and the reflector is fixed and blocked at the top of the side wall.

The second aspect of the present invention provides an under-screen optical fingerprint system, including a display panel, a backlight module, and the above fingerprint identification module. The backlight module is used to provide a backlight source for the display panel, and the fingerprint identification module is arranged on the display panel. And the backlight module.

In a specific embodiment of the present invention, the backlight module is arranged obliquely with respect to the display panel, and the fingerprint recognition module is arranged between the backlight module and the side with a larger distance between the display panel.

In the specific embodiment of the present invention, the fingerprint identification module is fixed on the display panel.

In a specific embodiment of the present invention, the fingerprint identification module is arranged at a position corresponding to the non-display area of the display panel.

In the specific embodiment of the present invention, it further includes a light source assembly, the light source assembly includes a light source, and the light emitting surface of the light source faces the fingerprint recognition area of the display panel to illuminate the finger.

In a specific embodiment of the present invention, the light source assembly is arranged between the display panel and the fingerprint recognition module.

In a specific embodiment of the present invention, the light source is an infrared light source.

In a specific embodiment of the present invention, the light source assembly further includes an infrared transmissive shielding member capable of transmitting infrared light, and the infrared transmissive shielding member shields between the display panel and the infrared light source to shield the infrared light source.

A third aspect of the present invention provides an electronic device including the above-mentioned under-screen optical fingerprint system.

The invention provides a fingerprint identification module, an under-screen optical fingerprint system and an electronic device. The fingerprint identification module is arranged under the display panel. The fingerprint identification module includes: an optical lens group, a reflector, and a fingerprint identification chip. The reflective surface faces the outside of the display panel, and at least part of the reflective surface of the reflector faces the sensing surface of the fingerprint identification chip. The optical lens group is used to converge the light reflected by the finger on the surface of the display panel and form an image on the sensing surface. The optical lens group includes at least One lens, and the optical axis of the object side surface and/or the optical axis of the image side surface of at least one lens and the horizontal direction have an included angle of less than 90°. By making the optical axis of the object side surface of at least one lens and/or the optical axis of the image side surface and the horizontal direction have an angle of less than 90°, even if the object side surface and/or image side surface of the at least one lens are relative to the vertical The direction is inclined at a certain angle, which can effectively correct asymmetric aberrations, thereby improving the fingerprint recognition accuracy of the fingerprint recognition module.

Description of the drawings

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

FIG. 1 is a schematic structural diagram of a fingerprint identification module provided by Embodiment 1 of the present invention;

2 is a schematic structural diagram of an optical lens group in a fingerprint recognition module provided by Embodiment 1 of the present invention;

3 is a schematic diagram of the structure of an under-screen optical fingerprint system in the prior art;

4 is a schematic structural diagram of an under-screen optical fingerprint system provided in Embodiment 4 of the present invention;

FIG. 5 is a schematic diagram of another structure of the under-screen optical fingerprint system provided in the fourth embodiment of the present invention.

Description of reference signs:

1-display panel; 2.82-backlight module; 3,83-fingerprint recognition module; 5,86-finger; 11-first surface; 12-fingerprint recognition area; 6-light source assembly; 8-optical lens group 9-Reflector; 10-Fingerprint recognition chip; 101-Sensing surface; 61-Light source; 62-Infrared shielding member; 63-Horizontal plate; 64-Vertical plate; 21-Reflective sheet; 22-Light guide plate; 23 , 84-diffusion sheet; 24-lower prism film; 25-upper prism film; 26-second surface; 31-fixed support; 32-bottom wall; 33-side wall; 34-opening; 81-aperture; 80- Liquid crystal display panel; 85-prism film.

detailed description

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

The technical solutions of the present invention will be described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments.

Example one

Fig. 1 is a schematic structural diagram of a fingerprint identification module provided by embodiment 1 of the present invention; Fig. 2 is a schematic structural diagram of an optical lens group in a fingerprint recognition module provided by embodiment 1 of the present invention; as shown in Figs. 1 and 2, fingerprint recognition The module 3 is arranged under the display panel. The fingerprint recognition module 3 includes an optical lens group 8, a reflector 9 and a fingerprint recognition chip 10. The reflective surface of the reflector 9 faces the outside of the display panel, and at least part of the reflective surface of the reflector 9 faces The sensing surface 101 of the fingerprint recognition chip 10, the fingerprint recognition light passes through the optical lens group 8, and is reflected on the sensing surface 101 of the fingerprint recognition chip 10 through the reflector 9. The optical lens group 8 is used to make the fingers on the surface of the display panel escape The fingerprint recognition light formed by reflection converges and forms an image on the sensing surface 101. The optical lens group 8 includes at least one lens. In this application, for the convenience of description, the side of the lens close to the finger is called the object side surface of the lens, and the side of the lens close to the fingerprint identification chip 10 is called the image side surface. . In addition, the optical axis of the object side surface and/or the optical axis of the image side surface of the at least one lens has an included angle of less than 90° with the horizontal direction. In the above solution, by making the optical axis of the object side surface of at least one lens and/or the optical axis of the image side surface and the horizontal direction have an angle of less than 90°, even if the object side surface and/or image side of the at least one lens The surface is inclined at a certain angle, which can effectively correct asymmetric aberrations, thereby improving the fingerprint recognition accuracy of the fingerprint recognition module.

Under normal circumstances, when the lens is set upright, the optical axis of the object side surface and the image side surface extend in the horizontal direction, while the optical axis of the object side surface and/or the optical axis of the image side surface in this application is inclined by one toward the image side Acute angle. Among them, the optical axis of a surface of the lens specifically refers to a cut plane at the center of the surface. A straight line perpendicular to the cut plane and passing through the center is the optical axis. For example, take a lens near the object side in FIG. 1 as an example To explain. The optical axis of the object-side surface of the lens is denoted by O1, and the optical axis of the image-side surface is denoted by O2. As can be seen from Figure 1, the optical axis O2 of the image-side surface and the horizontal direction have an acute angle θ', The optical axis O1 of the object side surface extends in the horizontal direction. It corresponds to the above-mentioned making the optical axis of the image side surface of the lens and the horizontal direction have an angle θ'.

The recognition process of the fingerprint recognition module 3 of the above structure is that the fingerprint detection light formed on the finger passes through the display panel and is incident on the optical lens group 8, and passes through the optical lens group 8 to illuminate the reflector 9, and passes The reflector 9 is reflected on the sensing surface 101 of the fingerprint identification chip 10, where the optical lens group 8 is used to converge the fingerprint identification light and form an image on the sensing surface 101. Finally, the fingerprint image is collected and recognized by the fingerprint recognition chip 10.

By arranging a reflector 9 between the optical lens group 8 and the fingerprint identification chip 10 as described above, the light passing through the optical lens group 8 is reflected by the reflector 9 before being incident on the fingerprint identification chip 10, that is, the optical path is folded Compared with the case where the reflector 9 is not provided, under the same image distance, the distance between the fingerprint identification chip 10 and the optical lens group 8 can be reduced, thereby reducing the thickness of the fingerprint identification module 3.

Among them, the outside of the display panel refers to the outer area of the display panel, and refers to the area above the display panel facing the user. The reflective surface of the reflector 9 facing the outside of the display panel means that the reflective surface of the reflector 9 is set toward the upper side of the display panel, and the reflective surface At least part of the reflective surface of the device 9 faces the sensing surface 101 of the fingerprint identification chip 10 to ensure that the fingerprint detection light passing through the optical lens group 8 can be reflected by the reflector 9 and incident on the sensing surface 101. The reflector 9 can be an infrared reflector or another reflector 9 with a reflective surface. The main function of the optical lens group 8 is to make the fingerprint detection light on the finger 5 form a reduced and clear fingerprint image, and to form the fingerprint image on the sensing surface 101 of the fingerprint identification chip 10. Therefore, the optical lens The group 8 may include at least one lens for condensing light, for example, may include at least one convex lens. The fingerprint recognition chip 10 can collect and recognize fingerprint information through natural white light or infrared light and other light of some specific wavelength bands, and an optical sensor can be selected.

Further, the optical lens group 8 further includes an aperture 81, which is arranged at the side of at least one lens. The aperture 81 is a device for controlling the amount of light passing through the lens, and the amount of light passing through the lens is controlled by changing the structural size of the aperture 81. For its setting position, for example, it can be set between two adjacent lenses, it can also be set to the side of the lens closest to the object side, or it can be set to the side of the lens closest to the image side. The specific location is not specified. limit. Of course, in the case where the optical axis of the object side surface and/or the optical axis of the image side surface of at least one lens and the horizontal direction have an angle of less than 90°, it can be considered that the axis and the horizontal direction of the aperture 81 also have an angle of less than 90°. °The included angle is convenient for use with the lens.

Furthermore, the object-side surface and/or the image-side surface of at least one lens is aspherical, preferably a rotationally symmetrical aspherical surface, which can reduce lens molding errors and improve the mass production feasibility of the entire optical lens group 8. More preferably, it may be a rotationally symmetric even-order aspheric surface. In addition, in the optical lens group 8, the object side surface and/or the image side surface of the lens closest to the image side is a rotationally symmetric aspheric surface. In this way, distortion and imaging aberrations can be corrected by adjusting the aspheric coefficients, and the imaging quality of the optical lens group 8 can be improved, thereby increasing the recognition accuracy.

In addition, in order to further reduce the influence of visible light on the fingerprint identification module 3, it is also possible to consider making the optical lens group 8 include an infrared-transmitting filter, which is arranged at the side of at least one lens, or is arranged on the fingerprint identification chip 10. The surface of, can transmit infrared detection light with fingerprint signal, and filter out visible light at the same time, which can improve the imaging quality of the optical lens group 8, thereby increasing the recognition accuracy. For its installation position, it may be preferable to arrange the infrared-transmitting filter in the optical lens group 8 on the object side surface of the lens closest to the object side. Regarding the method of forming the filter, for example, it may be formed by vapor deposition.

As mentioned above, the optical lens group 8 is prone to distortion and imaging aberrations during the fingerprint imaging process, which affects the imaging quality of the module and reduces the accuracy of fingerprint recognition. Therefore, for the optical lens group 8 The choice of parameters is very important. Next, a case where the optical lens group 8 is composed of two lenses and one diaphragm 81 will be described as an example.

As shown in FIG. 2, the optical lens group 8 includes a first lens 82 and a second lens 83 arranged in sequence from the object side to the image side. The aperture 81 is arranged between the first lens 82 and the second lens 83, and the fingerprint recognition light is transparent. After passing through the first lens 82, the aperture 81, and the second lens 83, it is irradiated to the reflective surface of the reflector 9.

Optionally, the optical axis of the object side surface of the first lens 82 is parallel to the horizontal direction. Further, in order to correct asymmetry aberrations as much as possible, improve the imaging quality of the optical lens group 8, and thereby increase the accuracy of fingerprint recognition, the following conditions need to be met:

The angle between the optical axis O2 of the image side surface of the first lens 82 and the horizontal direction is θ1, which satisfies 5°<θ1<25°.

In addition, optionally, the focal length of the first lens 82 is f1, and the radius of curvature of the image side surface of the first lens 82 is R2, satisfying: f1/R2>-2; and/or, the refractive index of the first lens 82 n1 satisfies: n1>1.50, and the dispersion coefficient v1 of the first lens 82 satisfies: v1>53.

Optionally, the included angle between the axis O3 of the aperture 81 and the horizontal plane is θ2, which satisfies 5°<θ2<25°.

Optionally, the angle between the optical axis O4 of the image side surface and the optical axis O4 of the object side surface of the second lens 83 and the horizontal plane is both θ3, which satisfies 5°<θ3<25°.

Further, the focal length of the second lens 83 is f2, the radius of curvature of the object side surface of the second lens 83 is R3, and the radius of curvature of the image side surface of the second lens 83 is R4, which satisfies: 0<f2/R3<1.5 -2<f2/R4<0; and/or, the refractive index n2 of the second lens 83 satisfies: n2>1.50, and the dispersion coefficient v2 of the second lens 83 satisfies: v2>53.

In order to facilitate better focusing and imaging of the fingerprint detection light reflected by the finger 5, θ1=θ2=θ3 can be selected.

In addition, optionally, in order to reduce the influence of the imaging module on the screen display, the distance between the reflective surface of the reflector and the surface of the display panel 1 close to the backlight module 2 should be less than 1.7 mm; and/or, the optical lens group The overall focal length of 8 is less than 1.2 mm.

In the following, the object-side surface of the first lens 82 is a flat surface, the image-side surface of the first lens 82 is a flat surface, the object-side surface of the second lens 83 and the image-side surface of the second lens 83 are aspherical surfaces, and θ1=θ2=θ3 Take an example to illustrate.

In this solution, the overall focal length of the optical lens group is f, the vertical distance from the inner surface of the display panel to the reflective surface of the reflector is H, the focal length of the second lens is f2, and the radius of curvature of the object side surface of the second lens is R3, the radius of curvature of the image side surface of the second lens is R4.

The following conditions need to be met: f = 0.724 mm; H = 1.304 mm; θ = 15.031°; f2/R3 = 1.105; f2/R4 = -0.992.

The parameters of each lens meet the following Table 1:

Table 1:

Table 2 shows the aspherical high-order coefficients A2, A4, A6, A8, A10, A12, A14, A16 of the aspheric lens, where the coefficients of A2 are all 0:

Table 2:

The following will continue to introduce the fingerprint identification module of the present application. Optionally, the reflector 9 and the fingerprint identification chip 10 are arranged at intervals in the thickness direction of the display screen, and the fingerprint identification chip 10 is arranged between the reflector 9 and the display panel 1, and The optical lens group 8 is arranged on the side of the reflector 9 and the fingerprint recognition chip 10.

Further, in order to fix the fingerprint identification chip 10, the reflector 9, the optical lens group 8 and other components on the inner surface of the display panel 1, the fingerprint identification module 3 further includes a fixed support 31, a reflector 9, and a fingerprint identification chip 10 and the optical lens group 8 are both fixed on the fixed support 31, and the fixed support 31 and the display panel 1 are relatively fixed. The fixing support 31 may be an integrally formed part, which can improve the accuracy of fixing each component compared with the case where the parts are formed separately and then bonded to each other.

In addition, the fingerprint identification chip 10 is a photosensitive element. In order to avoid the interference of the light in the surrounding environment of the fingerprint identification module 3 on the fingerprint identification chip 10, the fixed support 31 can also be set to be able to carry out the photosensitive surface of the fingerprint identification chip 10. The shielding structure is specifically optional. The fixed support 31 includes a bottom wall 32 and a side wall 33. The fingerprint identification chip 10 is arranged on the bottom wall 32. The side wall 33 is arranged around the outer side of the fingerprint identification chip 10. The side wall 33 is provided with an opening 34 for passing the fingerprint detection light, the optical lens group 8 is arranged at the side of the opening 34, and the reflector 9 is fixed and shielded at the top of the side wall 33. Specifically, the bottom end of the fingerprint recognition chip 10 can be fixed on the circuit board, and the circuit board is fixed on the bottom wall 32. In addition, the sensing surface 101 of the fingerprint recognition chip 10 is generally arranged on the top surface, and the fingerprint recognition chip 10 also has and On the side surface adjacent to the sensing surface 101 of the top surface, the side wall 33 can be arranged around the outside of the side surface of the fingerprint identification chip 10, and the opening 34 on the side wall 33 is provided with an optical lens group 8 on the side, so as to facilitate the transmission of the optical lens group 8. The fingerprint recognition light enters the inside of the side wall 33, and the reflector 9 is fixed and shielded at the top of the side wall 33, so that the reflector 9, the side wall 33, and the bottom wall 32 can jointly enclose a space that can accommodate the fingerprint recognition chip 10. At the same time, the space also has an opening 34 for the light passing through the optical lens group 8 to enter and irradiate the reflector 9.

In order to make the reflector 9 and the fingerprint identification chip 10 spaced apart in the thickness direction of the display screen, the height of the top of the side wall 33 from the bottom wall 32 needs to be greater than the height of the sensing surface 101 of the fingerprint identification chip 10 from the bottom wall 32. In addition, the specific value of the distance between the reflective surface of the reflector 9 and the sensing surface 101 of the fingerprint identification chip 10 can be selected according to the focal length of the optical lens group 8 and the distance between the optical lens group 8 and the reflector 9 and so on. Repeat it again.

In this embodiment, the fingerprint recognition module is arranged under the display panel. The fingerprint recognition module includes an optical lens group, a reflector, and a fingerprint recognition chip. The reflective surface of the reflector faces the outside of the display panel, and at least a part of the reflective surface of the reflector Facing the sensing surface of the fingerprint identification chip, the optical lens group is used to converge the light reflected by the finger on the surface of the display panel and image on the sensing surface. The optical lens group includes at least one lens, and the optical axis of the object side surface of the at least one lens is /Or the optical axis of the image side surface and the horizontal direction have an included angle of less than 90°. In the above solution, by setting the object side surface and/or image side surface of at least one lens at a certain angle with respect to the vertical direction, asymmetric aberrations can be effectively corrected, thereby improving the fingerprint recognition accuracy of the fingerprint recognition module.

Example two

In this embodiment, on the basis of Embodiment 1, the selection of some lens parameters of the first lens and the second lens has been improved, and the remaining parts are the same as in Embodiment 1, and will not be repeated here. On the basis of the first embodiment, in this embodiment, the object side surface of the first lens 82 is flat, the image side surface of the first lens 82 is flat, and the object side surface of the second lens 83 and the second lens 83 The image side surface is aspherical and θ1=θ2=θ3, the overall focal length of the optical lens group 8 is f, the vertical distance from the inner surface of the display panel to the reflecting surface of the reflector is H, the focal length of the second lens 83 is f2, The curvature radius of the object side surface of the second lens 83 is R3, and the curvature radius of the image side surface of the second lens 83 is R4.

The following conditions need to be met:

f=1.163 mm; H=1.489 mm; θ=14.374°; f2/R3=1.378; f2/R4=-0.543.

The parameters of each lens meet the following Table 3:

table 3:

Table 4 is the aspherical high-order coefficients A2, A4, A6, A8, A10, A12, A14, A16 of the aspheric lens, where the coefficients of A2 are all 0:

Table 4:

In this implementation, the selection of some lens parameters of the first lens and the second lens is improved, so that the correction effect of imaging aberration and distortion is better.

Example three

On the basis of the first and second embodiments, this embodiment has improved the type of the curved surface of the image side surface of the first lens 82 and the selection of some parameters of the first lens 82 and the second lens 83. One is the same and will not be repeated here. On the basis of Embodiment 1, in this embodiment:

The object-side surface of the first lens 82 is a flat surface, the image-side surface of the first lens 82 is aspherical, the object-side surface of the second lens 83 and the image-side surface of the second lens 83 are aspherical, and θ1=θ2=θ3, optical The overall focal length of the lens group is f, the vertical distance from the inner surface of the display panel to the reflective surface of the reflector is H, the focal length of the first lens 82 is f1, the radius of curvature of the object side surface of the first lens 82 is R1, The radius of curvature of the image side surface of the lens 82 is R2; the focal length of the second lens 83 is f2, the radius of curvature of the object side surface of the second lens 83 is R3, and the radius of curvature of the image side surface of the second lens 83 is R4.

The following conditions need to be met:

f=0.658 mm; H=1.305 mm; θ=14.976°; f1/R1=0; f1/R2=-1.866; f2/R3=0.881; f2/R4=-1.124.

The parameters of each lens meet the following Table 5:

table 5:

Table 6 shows the aspherical high-order coefficients A2, A4, A6, A8, A10, A12, A14, A16 of the aspheric lens, where the coefficients of A2 are all 0.

Table 6:

In this implementation, the shape of the image side surface of the first lens and the selection of some lens parameters of the first lens and the second lens are improved, so that the correction effect of imaging aberration and distortion is better.

Example four

Fig. 3 is a schematic structural diagram of an under-screen optical fingerprint system in the prior art, Fig. 4 is a schematic structural diagram of an under-screen optical fingerprint system provided in embodiment 4 of the present invention, and Fig. 5 is a schematic view of an under-screen optical fingerprint system provided in embodiment 4 of the present invention Schematic diagram of another structure of the system. As shown in Figure 3, the prior art under-screen optical fingerprint system includes: a liquid crystal display panel 80, a backlight module 82 and a fingerprint recognition module 83. The backlight module 82 is arranged between the liquid crystal display panel 80 and the fingerprint recognition module 83 , The backlight module 82 from the inside of the liquid crystal display panel 80 toward the outside includes: a reflective sheet, a light guide plate, a diffuser 84, a prism film 85, a reflective polarized brightness enhancement film, etc. The fingerprint recognition module 83 generally includes an imaging device and a fingerprint recognition chip Wait. When in use, the infrared light emitted by an external light source is irradiated on the finger 86, and the fingerprint detection light reflected on the finger 86 passes through the backlight module 82 and is incident on the fingerprint recognition module 83. The fingerprint recognition module 83 uses the imaging device to remove the fingerprint. The detection light forms a fingerprint image, and the fingerprint image is collected and recognized through the fingerprint recognition chip.

However, in the above-mentioned under-screen optical fingerprint recognition system, the fingerprint detection light formed on the finger 86 needs to pass through the prism film 85 and the diffuser 84 to reach the fingerprint recognition module. The presence of the prism film 85 divides the fingerprint detection light into left and right. At the end, the presence of the diffuser 84 will cause serious scattering of the fingerprint detection light, which will interfere with the imaging of the fingerprint image. Therefore, the under-screen optical fingerprint recognition system has the problem of low fingerprint recognition accuracy. In order to solve this problem, you can Consider arranging the fingerprint identification module between the backlight module and the display panel. Optionally, the under-screen optical fingerprint system of this embodiment includes the display panel 1, the backlight module 2, and the ones provided in the first to third embodiments. The fingerprint identification module 3, the backlight module 2 is used to provide the backlight source for the display panel 1. The fingerprint identification module 3 is arranged between the display panel 1 and the backlight module 2, and is used to receive the reflection of the finger 5 above the display panel 1. The light, that is, the fingerprint detection light reflected by the finger 5, performs fingerprint recognition. The specific structure, function and principle of the fingerprint identification module 3 are described in detail in the first to third embodiments, and will not be repeated here.

The backlight module 2 is generally located behind the display panel 1, and its function is to supply sufficient brightness and uniformly distributed surface light sources so that the display panel 1 can display images normally. The backlight module 2 from the inner side to the outer side of the display panel 1 includes: a reflective sheet 21, a light guide plate 22, a diffuser sheet 23, a lower prism film 24, an upper prism film 25, a reflective polarizing brightness enhancement film, and the like. Among them, the light source emitted by the LEDs in the backlight module 2 passes through the light guide plate 22 to form a surface light source. After the diffuser 23, the lower prism film 24, the upper prism film 25 and the reflective polarizing brightening film, the light source is formed with a certain polarization state.的白光, provides a light source for the display panel 1.

The display panel 1 described in this embodiment may be a liquid crystal display panel, and the fingerprint recognition module 3 is an optical fingerprint recognition module 3 using optical fingerprint recognition technology, and is used to receive fingerprint detection formed by the reflection of the finger 5 above the display panel 1. Light and fingerprint recognition. The fingerprint recognition module 3 of this embodiment is arranged between the display panel 1 and the backlight module 2. The fingerprint detection light reflected by the finger 5 above the display panel 1 can be directly irradiated to the fingerprint recognition module 3 through the display panel 1. Fingerprint recognition is performed above. Compared with the prior art, the light reflected by the finger 5 does not need to pass through the imaging interference of the prism film of the backlight module 2, the diffusion sheet 23, etc., and can be directly irradiated onto the fingerprint recognition module 3 for fingerprint recognition. Therefore, the accuracy of fingerprint recognition is high.

Compared with the prior art, in this application, the fingerprint recognition module 3 is arranged between the display panel 1 and the backlight module 2, which may make the gap between the display panel 1 and the backlight module 2 larger, resulting in the display panel 1. In order to avoid the occurrence of this situation, the backlight module 2 and the display panel 1 can be inclined to each other to locally reduce the distance between the two. Specifically, as shown in Figure 4, as In an alternative embodiment, the backlight module 2 is arranged obliquely with respect to the display panel 1, and the fingerprint identification module 3 is arranged between the backlight module 2 and the side of the display panel 1 with a larger distance. The backlight module 2 is inclined with respect to the display panel 1. The backlight module 2 and the display panel 1 may be inclined between the surfaces facing each other. For example, the display panel 1 includes a first surface 11 facing the inner side of the display panel 1. Group 2 includes a second surface 26 facing the display panel 1. The first surface 11 and the second surface 26 are arranged opposite to each other. Here, when the backlight module 2 is arranged obliquely with respect to the display panel 1, the second surface 26 is opposite to the first surface 11. Tilt setting. The distance between the backlight module 2 and the display panel 1 may specifically refer to the distance between the surfaces facing each other, for example, the distance between the first surface 11 and the second surface 26. The fingerprint identification module 3 is arranged between the backlight module 2 and the side of the display panel 1 with a larger distance, specifically referring to the fingerprint identification module 3 arranged on the first surface 11 and the second surface 26 with a larger distance. Between the sides.

The second surface 26 is the light-emitting surface of the backlight module 2, and the second surface 26 is arranged obliquely with respect to the first surface 11, which specifically refers to that the backlight module 2 and the display panel 1 are arranged non-parallel, so that the light-emitting surface of the backlight module 2 and The first surface 11 of the display panel 1 is arranged relatively obliquely, and the fingerprint identification module 3 is arranged between the first surface 11 and the second surface 26 with a larger distance, which means that when the first surface 11 and the second surface When the 26 is inclined, the distance between the different parts of the first surface 11 and the second surface 26 is different. For example, referring to the cross-sectional view shown in FIG. 4, the first surface 11 and the second surface 26 are located on the left side. The distance between the first surface 11 and the second surface 26 on the right side is greater than the distance between the fingerprint recognition module 3 can be installed on the first surface 11 and the second surface 26 on the left side. between. Of course, the explanation here is that the distance between the left part of the first surface 11 and the second surface 26 is relatively large, and the distance between the right part of the first surface 11 and the second surface 26 may be relatively large. , Or the front side part (corresponding to the paper face inward direction is the front side) has a larger spacing, or the rear side part (corresponding to the paper face outward direction is the back side) has a larger spacing, or other parts have a larger spacing Larger. In the above-mentioned case, it is sufficient to ensure that the fingerprint identification module 3 is arranged in the part with a larger distance, and the above-mentioned transformations fall within the scope of the present application. In addition, the fingerprint recognition module 3 is arranged between the first surface 11 and the side with a larger distance between the second surface 26, and may be arranged at the left end of the backlight module 2 as shown in FIG. 4, or it may be At a position slightly to the right, as long as it can be achieved that the fingerprint identification module 3 can be roughly arranged on the left part of the first surface 11 and the second surface 26 with a larger distance.

Under the premise that the fingerprint recognition module 3 is arranged between the display panel 1 and the backlight module 2, if the display panel 1 and the backlight module 2 are arranged in parallel, as shown in the comparison diagram of FIG. 5, the display panel 1 and the backlight module The spacing between the groups 2 is obviously larger than that shown in FIG. 4, which will reduce the brightness of the display panel 1 and affect the user experience. In practice, the display panel 1 and the backlight module 2 are inclined to each other. Taking into account the user’s usage habits, the display panel 1, that is, the first surface 11 can be arranged horizontally, and the backlight module 2 can be arranged inclined, so that the second The surface 26 is arranged obliquely with respect to the first surface 11. Of course, the backside surface of the backlight module 2 facing away from the display panel 1 can also be parallel to the second surface 26, so as to form a space between the backside surface and the housing of the electronic device that can accommodate components such as circuit boards. To further reduce the thickness of the entire electronic device.

Since the display panel 1 is generally arranged horizontally with the housing of electronic devices such as mobile phones, and in this embodiment, the backlight module 2 is arranged obliquely with respect to the display panel 1. Therefore, in order to ensure that the fingerprint identification module 3 can detect the fingerprint formed by the finger 5 For better identification, the fingerprint identification module 3 can preferably be fixed on the display panel 1.

Furthermore, the fingerprint identification module 3 needs to be arranged at a position corresponding to the non-display area of the display panel 1. This can avoid affecting the normal display of the display panel 1.

In addition, since the liquid crystal display panel 1 itself cannot emit light, in order to make the finger 5 form the fingerprint detection light, a light source 61 needs to be provided. Optionally, the under-screen optical fingerprint system of this embodiment further includes a light source assembly 6, which includes The light source 61, and the light emitting surface of the light source 61 faces the fingerprint recognition area 12 of the display screen, so as to irradiate the finger 5, and make the finger 5 reflect the light emitted from the light source 61 to form fingerprint detection light. The light source 61 here may be a light emitting diode or the like. Of course, in order to be distinguished from the surface light source emitted by the backlight, the light source 61 may be an infrared light source, such as an infrared light-emitting diode.

Regarding the position of the light source assembly 6, the light source assembly 6 can be arranged between the display panel 1 and the backlight module 2, so that the light emitted by the light source 61 can pass through the display panel 1 and irradiate the finger 5. More specifically, As shown in FIG. 4, the light source assembly 6 can be arranged between the fingerprint identification module 3 and the display panel 1. That is, the light source assembly 6 is arranged below the fingerprint identification module 3. Compared with the solution in which the light source assembly 6 and the fingerprint identification module 3 are arranged at the same height, the light emitted by the light source assembly 6 can avoid causing the fingerprint identification chip 10 as much as possible. interference.

In addition, in order to prevent the light source assembly 6 from being seen on the front of the display panel 1, an infrared light-transmitting shield 62 can also be optionally provided between the infrared light source 61 and the display panel 1. Specifically, the light source assembly 6 also includes a light source capable of transmitting infrared light. The infrared transparent shield 62 is shielded between the display screen and the infrared light source 61 to shield the infrared light source 61 so that the infrared light source 61 is invisible on the front of the display panel 1. Of course, the infrared-transmitting shield 62 can transmit the infrared light emitted by the infrared light source 61 and does not affect the formation of fingerprint detection light on the surface of the finger 5. As shown in FIG. 2, the infrared transparent shield 62 may include a horizontal plate 63 and a vertical plate 64. Both the horizontal plate 63 and the vertical plate 64 are fixed on the first surface 11, and one end of the horizontal plate 63 and the vertical plate 64 One end of the light source 61 is connected so that the horizontal plate 63 and the vertical plate 64 jointly enclose a receiving cavity capable of accommodating the light source 61. The horizontal plate 63 and the vertical plate 64 may be transparent parts, and the surface is coated with infrared-permeable ink to prevent visible light from passing through and to allow infrared light to pass through.

In this embodiment, the under-screen optical fingerprint system includes a display panel, a backlight module, and the aforementioned fingerprint identification module. The backlight module is used to provide a backlight source for the display panel, and the fingerprint identification module is arranged between the display panel and the backlight module. between. By arranging the fingerprint recognition module between the display panel and the backlight module, the fingerprint detection light formed by the reflection of the finger above the display panel can be directly irradiated to the fingerprint recognition module through the display panel for fingerprint recognition, which is different from the existing Compared with technology, the light reflected by the finger does not need to pass through the imaging interference of the prism film, diffuser, etc. of the backlight module, and can be directly irradiated on the fingerprint recognition module for fingerprint recognition, so the accuracy of fingerprint recognition is higher.

Example five

This embodiment provides an electronic device that includes the under-screen optical fingerprint system in the fourth embodiment above. The electronic device may specifically be a liquid crystal display device, electronic paper, mobile phone, tablet computer, television, notebook computer, digital Electronic products or components such as photo frames, navigators, fingerprint locks, etc.

In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection or an intermediate connection. The medium is indirectly connected, which can be the internal communication between two elements or the interaction between two elements. For those of ordinary skill in the art, the specific meaning of the above-mentioned terms in the present invention can be understood according to specific circumstances.

In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", The orientation or positional relationship indicated by “outside” is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the pointed device or element must have a specific orientation, It is constructed and operated in a specific orientation, so it cannot be understood as a limitation of the present invention. In the description of the present invention, "plurality" means two or more, unless it is specifically specified otherwise.

The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, without having to use To describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein, for example, can be implemented in a sequence other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations of them are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to the clearly listed Those steps or units may include other steps or units that are not clearly listed or are inherent to these processes, methods, products, or equipment.

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

Claims

A fingerprint recognition module is arranged under the display panel, and is characterized in that it comprises: an optical lens group, a reflector and a fingerprint recognition chip. The reflective surface of the reflector faces the outside of the display panel, and the reflector At least a part of the reflective surface faces the sensing surface of the fingerprint recognition chip, the optical lens group is used to converge the light reflected by the finger on the display panel surface and form an image on the sensing surface, and the optical lens group includes at least one A lens, and the optical axis of the object side surface and/or the optical axis of the image side surface of the at least one lens and the horizontal direction have an included angle of less than 90°.
The fingerprint identification module according to claim 1, wherein the optical lens group further comprises an aperture, and the aperture is arranged at a side of the at least one lens.
The fingerprint identification module of claim 2, wherein the axis of the aperture and the horizontal direction have an included angle less than 90°.
The fingerprint identification module according to claim 2, wherein the optical lens group comprises a first lens and a second lens arranged in sequence from the object side to the image side, and the aperture is arranged between the first lens and the Between the second lenses, the fingerprint recognition light passes through the first lens, the aperture, and the second lens, and then irradiates the reflective surface of the reflector.
4. The fingerprint identification module of claim 4, wherein the optical axis of the object side surface of the first lens is parallel to the horizontal direction.
The fingerprint identification module according to claim 4, wherein the angle between the optical axis of the image side surface of the first lens and the horizontal direction is θ1, which satisfies 5°<θ1<25°.
The fingerprint identification module according to claim 6, wherein the focal length of the first lens is f1, and the radius of curvature of the image side surface of the first lens is R2, which satisfies: f1/R2>-2 ;and / or,

The refractive index n1 of the first lens satisfies: n1>1.50, and the dispersion coefficient v1 of the first lens satisfies: v1>53.
The fingerprint identification module of claim 4, wherein the angle between the axis of the aperture and the horizontal direction is θ2, which satisfies 5°<θ2<25°.
The fingerprint identification module of claim 4, wherein the angle between the optical axis of the image side surface and the optical axis of the object side surface of the second lens and the horizontal direction are both θ3, which satisfies 5°<θ3 <25°.
The fingerprint identification module according to claim 9, wherein the focal length of the second lens is f2, and the radius of curvature of the object side surface of the second lens is R3, and the image side of the second lens The radius of curvature of the surface is that R4 satisfies: 0<f2/R3<1.5; -2<f2/R4<0; and/or,

The refractive index n2 of the second lens satisfies: n2>1.50, and the dispersion coefficient v2 of the second lens satisfies: v2>53.
The fingerprint identification module according to claim 4, wherein the distance between the reflective surface of the reflector and the lower surface of the display panel is less than 1.7 mm; and/or, the overall focal length of the optical lens group Less than 1.2 mm.
The fingerprint identification module according to claim 4, wherein the included angle θ1 between the optical axis of the image side surface of the first lens and the horizontal direction, the included angle θ2 between the axis of the aperture and the horizontal direction, and The angle θ3 between the optical axis of the image side surface and the optical axis of the object side surface of the second lens and the horizontal direction satisfies: θ1=θ2=θ3.
The fingerprint identification module according to any one of claims 1-12, wherein the object side surface and/or the image side surface of the at least one lens is a rotationally symmetric aspheric surface.
The fingerprint identification module according to claim 13, wherein in the optical lens group, the object side surface and/or the image side surface of the lens closest to the image side is a rotationally symmetric aspheric surface.
The fingerprint identification module according to any one of claims 1-12, wherein the optical lens group further comprises an infrared transparent filter, and the infrared transparent filter is arranged at the side of at least one of the lenses. , Or set on the surface of the fingerprint recognition chip to filter out visible light.
15. The fingerprint identification module according to claim 15, wherein the infrared-transmitting filter is arranged on the object side surface of the lens closest to the object side in the optical lens group.
The fingerprint identification module according to any one of claims 1-12, wherein the reflector and the fingerprint identification chip are arranged at intervals in the thickness direction of the display panel, and the fingerprint identification chip is arranged at Between the reflector and the display panel, and the optical lens group is arranged on the side of the reflector and the fingerprint recognition chip.
The fingerprint identification module of claim 17, wherein the fingerprint identification module further comprises a fixed support, and the reflector, the fingerprint identification chip and the optical lens group are all fixed on the fixed On the support, the fixed support and the display panel are relatively fixed.
The fingerprint identification module according to claim 18, wherein the fixed support includes a bottom wall and a side wall, the fingerprint identification chip is disposed on the bottom wall, and the side wall surrounds the fingerprint identification The chip is arranged on the outside of the side surface, the side wall is provided with an opening for the fingerprint detection light to pass through, the optical lens group is arranged on the side of the opening, and the reflector is fixed and shielded at the top of the side wall .
An under-screen optical fingerprint system, characterized by comprising a display panel, a backlight module, and the fingerprint identification module according to any one of claims 1-19, the backlight module being used to provide a backlight for the display panel Source, the fingerprint identification module is arranged between the display panel and the backlight module.
The under-screen optical fingerprint system according to claim 20, wherein the backlight module is arranged obliquely with respect to the display panel, and the fingerprint identification module is arranged on the back light module and the display panel. Between the sides with larger spacing.
22. The under-screen optical fingerprint system of claim 21, wherein the fingerprint identification module is fixed on the display panel.
22. The under-screen optical fingerprint system of claim 20, wherein the fingerprint identification module is arranged at a position corresponding to a non-display area of the display panel.
The under-screen optical fingerprint system according to any one of claims 20-23, further comprising a light source assembly, the light source assembly comprising a light source, the light emitting surface of the light source faces the fingerprint recognition area of the display panel, To irradiate the finger.
The under-screen optical fingerprint system according to claim 24, wherein the light source assembly is arranged between the display panel and the fingerprint identification module.
The under-screen optical fingerprint system according to claim 24, wherein the light source is an infrared light source.
The under-screen optical fingerprint system according to claim 24, wherein the light source assembly further comprises an infrared transparent shielding member capable of transmitting infrared light, and the infrared transparent shielding member shields the display panel and the Between the infrared light sources to shield the infrared light sources.
An electronic device, characterized by comprising the under-screen optical fingerprint system according to any one of claims 20-27.