CN210324245U

CN210324245U - Fingerprint identification device

Info

Publication number: CN210324245U
Application number: CN201921944536.3U
Authority: CN
Inventors: 朱虹; 陆震生; 李重寰
Original assignee: Shanghai Oxi Technology Co Ltd
Current assignee: Shanghai Oxi Technology Co Ltd
Priority date: 2019-11-12
Filing date: 2019-11-12
Publication date: 2020-04-14
Anticipated expiration: 2029-11-12

Abstract

A fingerprint identification device, the fingerprint identification device comprising: the touch screen comprises a sensing surface and a light-emitting unit, wherein the light-emitting unit emits light rays which form reflected light through the sensing surface and are output; a convex lens group including a plurality of convex lenses, each of the convex lenses receiving the reflected light to converge to form a converging light beam; and the collimator comprises a plurality of collimation units which are arranged in parallel, each collimation unit corresponds to the convex lens one by one, and each collimation unit receives the convergent light beam output by the corresponding convex lens and collimates to form a collimated convergent light beam. The convex lens helps to increase the light intensity of the collimated converging light beam output by the collimating unit.

Description

Fingerprint identification device

Technical Field

The utility model relates to a fingerprint identification technical field especially relates to a fingerprint identification device.

Background

The fingerprint identification device can realize automatic fingerprint acquisition and is widely applied to equipment such as attendance machines, access controls, mobile phones or tablet computers.

According to the principle of fingerprint imaging, fingerprint identification devices can be classified into optical fingerprint identification devices, semiconductor capacitance identification devices, semiconductor heat-sensitive identification devices, semiconductor pressure-sensitive identification devices, and the like.

The optical fingerprint identification device mainly utilizes the refraction and reflection principles of light, the refraction angle of light emitted by a light source on uneven lines of fingerprints on the surface of a finger and the brightness of the reflected light are different, and a CMOS (complementary Metal Oxide semiconductor) optical device correspondingly collects picture information with different brightness degrees, so that the collection of the fingerprints is completed.

The optical fingerprint identification device has strong environmental adaptability, good stability and low production cost, so the optical fingerprint identification device is widely applied.

However, the structure of the existing optical fingerprint recognition device still needs to be improved.

SUMMERY OF THE UTILITY MODEL

The utility model provides a problem provide a fingerprint identification device helps improving collimation unit output the light intensity of collimation convergent light beam.

In order to solve the above problem, the utility model provides a fingerprint identification device, include: the touch screen comprises a sensing surface and a light-emitting unit, wherein the light-emitting unit emits light rays which form reflected light through the sensing surface and are output; a convex lens group including a plurality of convex lenses, each of the convex lenses receiving the reflected light to converge to form a converging light beam; and the collimator comprises a plurality of collimation units which are arranged in parallel, each collimation unit corresponds to the convex lens one by one, and each collimation unit receives the convergent light beam output by the corresponding convex lens and collimates to form a collimated convergent light beam.

Optionally, the collimating unit includes a light-transmitting column and a light-shielding layer, the light-shielding layer covers the surface of the sidewall of the light-transmitting column, the convex lens covers the top surface of the light-transmitting column, and the convex lens is located between the touch screen and the collimating unit.

Optionally, the fingerprint identification apparatus further includes: and the optical sensor receives the collimated convergent light beam output by the collimator to form a fingerprint image.

Optionally, the fingerprint identification apparatus further includes: an infrared cut-off layer located between the collimator and the optical sensor.

Optionally, the optical sensor includes a plurality of photosensitive pixel units, and the photosensitive pixel units correspond to the collimating units one to one.

Optionally, the refractive index of the convex lens is greater than 1.4 and less than 1.5.

Optionally, the height of the convex lens is greater than 3 μm and less than 30 μm.

Optionally, the light-transmitting pillar is cylindrical or prismatic.

Optionally, when the light-transmitting pillar is cylindrical, the ratio of the height of the light-transmitting pillar to the diameter of the bottom surface is greater than 10.

Optionally, the thickness of the light shielding layer is greater than 0.5 μm.

Optionally, the plurality of collimating units are arranged in an array, and the light shielding layers of adjacent collimating units are in contact with each other.

Optionally, the fingerprint identification apparatus further includes: and the euphotic layer is arranged between the collimator and the convex lens group.

Compared with the prior art, the technical scheme of the utility model have following advantage:

the fingerprint identification device comprises: touch screen, convex lens group and collimater. The touch screen comprises a sensing surface and a light emitting unit. The sensing surface of the touch screen is pressed by the fingers of a user, the light-emitting unit emits light, and the light is reflected by the surface of the finger to form reflected light carrying fingerprint information on the sensing surface. The convex lens group comprises a plurality of convex lenses, and each convex lens receives the reflected light to converge to form a convergent light beam. The convex lens can modulate the light direction of the reflected light in the process of converging the reflected light, namely the convex lens can pre-collimate the received reflected light, so that the directions of the convergent light beams output by the convex lens are consistent. The collimator comprises a plurality of collimation units which are arranged in parallel, each collimation unit corresponds to the convex lens one by one, and each collimation unit receives the convergent light beam output by the corresponding convex lens and collimates to form a collimated convergent light beam. Due to the pre-collimation effect of the convex lens, the direction consistency of the convergent light beam received by the collimator is better, more convergent light beams can be output by the collimator to form a collimated convergent light beam, and therefore the light intensity of the formed collimated convergent light beam can be improved.

Drawings

Fig. 1 is a schematic structural diagram of a fingerprint recognition device according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a collimator and a convex lens set of the fingerprint identification device shown in FIG. 1;

FIG. 3 is a schematic perspective view of the collimator shown in FIG. 2;

fig. 4 to fig. 6 are schematic structural diagrams corresponding to steps in an embodiment of the fingerprint identification method of the present invention;

fig. 7 to 11 are schematic structural diagrams corresponding to steps in an embodiment of a forming method of the present invention;

fig. 12 to 16 are schematic structural diagrams corresponding to steps in another embodiment of the forming method of the present invention.

Detailed Description

Now analyzed in connection with a fingerprint identification device, the fingerprint identification device comprising: the touch screen comprises a sensing surface and a light-emitting unit, wherein the light-emitting unit emits light rays which form reflected light through the sensing surface and are output; the collimator comprises a plurality of collimation units which are arranged in parallel, and the collimation units receive the reflected light to collimate to form a collimated light beam. Because the light emitted by the light source is reflected by the surface of the finger and then forms the reflected light on the sensing surface, the reflected light is divergent light, the direction difference of the light is large, a large amount of light can be filtered off in the process of passing through the collimating unit, and the collimated light beam output by the collimator is weak.

The inventors have studied the fingerprint recognition device and, through creative work, noticed that, by disposing a convex lens set between the touch screen and the collimator, the convex lens set includes a plurality of convex lenses, and the convex lenses receive the reflected light to converge to form a converging light beam, compared with the reflected light, the direction consistency of the converging light beam is better, so that more converging light beams can be output from the collimator to form a collimated converging light beam, which helps to improve the light intensity of the collimated converging light beam.

In order to make the aforementioned objects, features and advantages of the present invention more comprehensible, embodiments accompanied with figures are described in detail below.

Referring to fig. 1, a fingerprint identification apparatus includes a touch screen 100, a convex lens group, a collimator 200, and an optical sensor 300, where the touch screen 100 is adapted to output reflected light carrying fingerprint information. The convex lens group includes a plurality of convex lenses 240, and each of the convex lenses 240 receives the reflected light to converge to form a converging light beam. The collimator 200 includes a plurality of collimating units 210 arranged in parallel, where the collimating units 210 include light-transmitting pillars 220 and a light-shielding layer 230, and the light-shielding layer 230 covers the sidewall surfaces of the light-transmitting pillars 220. Each of the collimating units 210 corresponds to the convex lens 240 one by one, and each of the collimating units 210 receives the converging light beam output by the corresponding convex lens 240, and collimates the converging light beam to form a collimated converging light beam. The optical sensor 300 receives the collimated converging light beam output from the collimator 200 to perform image processing, thereby forming a fingerprint image.

The touch screen 100 includes a sensing surface 101 and a light emitting unit 103. The light emitting unit 103 emits light, the light is emitted to the sensing surface 101, and the light forms reflected light through the sensing surface 101. Specifically, when a user presses a finger on the sensing surface 101, the light emitted from the light emitting unit 103 is reflected by the surface of the finger to form the reflected light. Since the finger surface includes uneven ridges and valleys, wherein the valleys are in contact with the sensing surface 101, and the ridges are not in contact with the sensing surface 101, the intensity of the reflected light formed at the ridges and the valleys is different, and thus the reflected light carries fingerprint information.

In this embodiment, the top surface of the touch screen 100 serves as the sensing surface 101, and the touch screen 100 further has a connection surface 102 opposite to the sensing surface 101.

In this embodiment, the touch screen 100 is an OLED (Organic Light-Emitting Diode) screen.

The OLED screen material comprises an organic semiconductor material and a luminescent material. Under the drive of the electric field, electrons and holes in the organic semiconductor material are combined to form excitons, so that the molecules of the luminescent material are excited to emit visible light.

After the light emitted by the light emitting unit 103 is reflected by the surface of the finger, the formed reflected light is divergent light, and the light direction difference of the reflected light is large. If the optical sensor directly collects the reflected light, the quality of a fingerprint image formed by image processing using the reflected light is poor due to poor light direction consistency of the reflected light. Therefore, the reflected light output by the touch screen 100 needs to be modulated and collimated, so that the light direction collected by the optical sensor 300 has good consistency, and the quality of the fingerprint image formed by the optical sensor 300 is improved.

The convex lens 240 is located between the touch screen 100 and the collimator 200. The convex lens 240 is adapted to converge the reflected light output by the touch screen 100. The convex lens 240 can modulate the direction of the reflected light to reduce the tilt angle of a portion of the reflected light. The light direction of the formed converging light beam is more concentrated than the reflected light output by the touch screen 100. Thus, the convex lens 240 can pre-collimate the reflected light output by the touch screen 100. The subsequent convergent light beam is received by the collimator 200, the collimator 200 further collimates the convergent light beam, and since the light direction of the convergent light beam is concentrated, less convergent light beam is filtered out in the process of collimation, more convergent light beam is output by the collimator 200 to form a collimated convergent light beam, and thus the intensity of the collimated convergent light beam is high.

In other embodiments, the fingerprint recognition device further includes: and the euphotic layer is arranged between the collimator and the convex lens group.

Referring to fig. 2, in the present embodiment, the convex lens 240 has opposite flat surfaces 241 and convex surfaces 242. The flat surface 241 is attached to the top surface of the light-transmitting pillar 220, and the convex surface 242 protrudes toward the connecting surface 102 (refer to fig. 1). Light rays incident on the convex lens 240 are refracted on the convex surface 242, so that the light rays are converged toward the focal point of the convex surface 242.

In this embodiment, the refractive index of the convex lens 240 is greater than 1.4 and less than 1.5. The reflected light is refracted at the convex surface 242, and if the refractive index of the convex lens 240 is too large, the amount of deviation in the refraction direction is too large, which easily causes the light direction to be deflected to the sidewall of the light-transmitting pillar 220 and then absorbed by the light-shielding layer 230. If the refractive index of the convex lens 240 is too small, the converging effect of the convex surface 242 on the reflected light is affected. The refractive index of the convex lens 240 is in a proper range, which is helpful for the reflected light to enter the light transmission column 220 towards the bottom surface of the light transmission column 220 after being converged by the convex lens 240, so that the probability of the reflected light being transmitted by the light transmission column 220 is improved.

In this embodiment, the material of the convex lens 240 is glass. In other embodiments, the material of the convex lens 240 may also be a silicone material.

In this embodiment, the convex surface 242 is a circular arc surface, and a distance H2 between a vertex of the convex surface 242 and the plane 241 is greater than 3 μm and less than 30 μm. If the distance H2 between the vertex of the convex surface 242 and the plane 241 is too small, the curvature of the convex surface 242 will be too small, which affects the converging effect of the convex surface 242 on the reflected light. If the distance H2 between the vertex of the convex surface 242 and the plane 241 is too large, the curvature of the convex surface 242 is too large, and the reflected light is still easy to become divergent light after being converged by the convex surface 242 and then emitted through the plane 241. In addition, the distance H2 between the vertex of the convex surface 242 and the plane 241 is too large, which makes the height of the collimator 200 too large, and thus the fingerprint recognition device is not compact.

In this embodiment, the convex lens 240 is formed on the top surface of the light-transmitting pillar 220 by stamping.

The collimator 200 is located between the convex lens group and the optical sensor 300, and is adapted to collimate the convergent light beam output by the convex lens 240, filter out the convergent light beam having an excessively large inclination angle of the light direction, and allow only the convergent light beam having the inclination angle of the light direction within an appropriate range to pass through the collimator 200 to form the collimated convergent light beam, which is then received by the optical sensor 300.

The reflected light output by the touch screen 100 is converged by the convex lens 240 and then enters the collimator 200, and the direction of the converging light beam formed after the converging by the convex lens 240 is relatively concentrated, so that a small amount of the converging light beam is absorbed by the light shielding layer 230, and a large amount of the converging light beam is output by the collimator 200 to form a collimated converging light beam. Therefore, the light intensity value of the collimated convergent light beam collected by the optical sensor 300 is high, which is beneficial to improving the working efficiency of the optical sensor 300.

Referring to fig. 3, in the embodiment, the plurality of collimating units 210 are arranged in an array, and the light shielding layers 230 of adjacent collimating units 210 are in contact with each other, so as to reduce the convergent light beam incident on the optical sensor 300 through the gap between the adjacent collimating units 210, and improve the uniformity of the light direction collected by the optical sensor 300.

The light-transmitting pillar 220 has a cylindrical or prismatic shape. In this embodiment, the light-transmitting pillar 220 is cylindrical, and the manufacturing process is simple.

Referring to fig. 3, the light shielding layer 230 cooperates with the light-transmitting pillar 220 to collimate the converging light beam incident on the light-transmitting pillar 220. The ratio of the height H1 (refer to FIG. 2) and the bottom diameter L1 (refer to FIG. 2) of the light-transmitting pillars 220 affects the collimation effect of the light-shielding layer 230 and the light-transmitting pillars 220. The larger the ratio between the height H1 and the bottom diameter L1 of the light-transmitting pillar 220, the longer the time for the converging light beam to travel in the light-transmitting pillar 220, and the more easily the converging light beam with an inclined direction is absorbed by the light-shielding layer 230, so the better the collimation effect of the light-transmitting pillar 220 and the light-shielding layer 230 is.

The convex lens 240 helps to reduce the height H1 of the light-transmitting pillar 220 by utilizing the converging effect of the convex lens 240 on the reflected light, and the collimating effect of the collimator is improved without using the collimating unit with an excessively large height value, so that the convex lens 240 helps to reduce the height of the collimator 200, and the size of the collimator 200 is reduced.

In this embodiment, when the light-transmitting pillar 220 is cylindrical, the ratio of the height H1 of the light-transmitting pillar 220 to the bottom diameter L1 is greater than 10.

In other embodiments, the light-transmitting pillars 220 are prism-shaped. When the prism is a regular triangular prism, since the regular triangular prisms can be spread over the entire two-dimensional plane without leaving a gap, the collimating units 210 are closely arranged, and thus, it is possible to prevent a part of the condensed light beam from being incident to the optical sensor 300 through the gap between the adjacent collimating units 210. When the prism is a regular quadrangular prism or a regular hexagonal prism, it can also be ensured that no gap is left between the adjacent collimating units 210, thereby ensuring the collimating effect of the collimator 200.

The light shielding layer 230 encloses a cavity, and the shape of the cavity is consistent with the shape of the light-transmitting pillar 220. When the light-transmitting pillar 220 is cylindrical, a projection of the outer wall of the light-shielding layer 230 toward the connecting surface 102 is circular or regular polygon. When the light-transmitting pillars 220 are prism-shaped, the projection of the outer wall of the light-shielding layer 230 toward the connecting surface 102 is a regular polygon.

In this embodiment, the thickness D1 of the light-shielding layer 230 is greater than 0.5 μm. If the thickness D1 of the light shielding layer 230 is too small, the light absorption performance of the light shielding layer 230 is affected, and the light shielding layer 230 is difficult to completely absorb the converging light beam emitted to the sidewall of the light-transmitting pillar 220, thereby affecting the collimation effect of the collimating unit 210.

In this embodiment, when the thickness D1 of the light-shielding layer 230 is 1 μm, the light-shielding layer material with a thickness range of 400nm to 1100nm has a light transmittance of less than 1%.

In this embodiment, the light shielding layer 230 at the peripheral edge of the collimator 200 is bonded to the edge of the connection surface 102, specifically, bonded by a double-sided adhesive foam or an adhesive tape, so as to fix the relative position of the collimator 200 and the touch screen 100.

Referring to fig. 1, in this embodiment, the optical sensor 300 is located on a side of the collimator 200 opposite to the touch screen 100, and the optical sensor 300 collects a collimated converging light beam output by the collimator 200 to form a fingerprint image.

In this embodiment, the optical sensor 300 includes a plurality of photosensitive pixel units, and the photosensitive pixel units correspond to the light-transmitting pillars 220 and are adapted to receive the collimated converging light beams transmitted by the corresponding light-transmitting pillars 220.

In this embodiment, the optical sensor 300 is a CMOS optical sensor. In other embodiments, the optical sensor 300 may also be a tft (thin Film transistor) process based optical sensor.

In this embodiment, the fingerprint identification apparatus further includes: an infrared cut-off layer 700, the infrared cut-off layer 700 being located between the collimator 200 and the optical sensor 300.

When the fingerprint recognition device is used in an outdoor environment, a finger of a user presses the sensing surface 101 of the touch screen 100, infrared light in sunlight easily penetrates through the finger of the user and is received by the convex lens group together with reflected light carrying fingerprint information, so that infrared light exists in the formed convergent light beam and the collimated convergent light beam. Infrared light in the collimated converging light beam is interference light, and if the interference light is collected by the optical sensor 300, the formation quality of a fingerprint image is affected.

The infrared cut-off layer 700 is located between the collimator 200 and the optical sensor 300, and can filter out infrared light in the collimated converging light beam, which is helpful for improving the definition of a fingerprint image, so as to improve the identification accuracy of a fingerprint identification device.

If the thickness of the infrared cut-off layer 700 is too thick, the volume of the fingerprint identification device is too large, and it is difficult to meet the requirement of miniaturization of the fingerprint identification device. If the thickness of the infrared cut-off layer 700 is too thin, the infrared light filtering effect of the infrared cut-off layer 700 is affected, and a small amount of infrared light still exists in the collimated converging light beam collected by the optical sensor 300.

In this embodiment, the infrared cut-off layer material with a thickness ranging from 650nm to 1000nm has a light transmittance of less than 1% for infrared light.

The utility model discloses still provide a fingerprint identification method, refer to fig. 4 to fig. 6 below, carry out detailed introduction to fingerprint identification method.

Referring to fig. 4, a touch screen 100 is provided, where the touch screen 100 includes a sensing surface 101 and a light emitting unit 103, and the light emitting unit 103 emits light, and the light passes through the sensing surface 101 to form a reflected light 401 and is output.

In this embodiment, the top surface of the touch screen 100 serves as the sensing surface 101. The touch screen 100 further has a connection face 102 opposite the sensing face 101. The light emitting unit 103 is located between the sensing surface 101 and the connection surface 102, and the light emitting unit 103 is close to the connection surface 102.

When a user presses a finger on the sensing surface 101, the light emitted by the light emitting unit 103 is emitted to the sensing surface 101, and is reflected by the finger surface to form the reflected light 401, and the reflected light 401 is emitted to the connection surface 102 and is emitted through the connection surface 102.

The reflected light 401 is divergent light, and the direction of the reflected light 401 is greatly different.

Referring to fig. 5, a convex lens group is provided, and the convex lens group includes a plurality of convex lenses 240, and each of the convex lenses 240 receives the reflected light 401 to perform a converging process, forms a converging light beam 402, and outputs the converging light beam.

In the converging process, the reflected light 401 is refracted by the surface of the convex lens 240 and is focused on the focal point of the convex lens 240, so that the direction of the formed converging light beam 402 is more consistent than that of the reflected light 401. The convergent light beam 402 is incident on the collimator, and since the light direction of the convergent light beam 402 is concentrated, the convergent light beam 402 easily passes through the collimator 200 to form a collimated convergent light beam.

In this embodiment, the refractive index of the convex lens 240 is greater than 1.4 and less than 1.5.

Referring to fig. 6, a collimator 200 is provided, where the collimator 200 includes a plurality of collimating units 210 arranged in parallel, the collimating units 210 and the convex lenses 240 are disposed in a one-to-one correspondence, and each collimating unit 210 receives the converging light beam 402 output by the corresponding convex lens 240, performs a collimating process to form a collimated converging light beam 403, and outputs the collimated converging light beam 403.

In this embodiment, the collimating unit 210 includes a light-transmitting pillar 220 and a light-shielding layer 230, and the light-shielding layer 230 covers a sidewall surface of the light-transmitting pillar 220.

The light shielding layer 230 is made of a light absorbing material, and the converging light beam 402 incident on the collimator 200 is absorbed by the light shielding layer 230 when the converging light beam irradiates the light shielding layer 230. Since the light shielding layer 230 covers the sidewall surface of the light transmitting pillar 220, the converging light beam 402 emitted from the top surface of the light transmitting pillar 220 to the sidewall of the light transmitting pillar 220 is absorbed by the light shielding layer 230. Thereby, the collimator 200 collimates the converging light beam 402. The collimated converging beam 403 output by the collimator 200 has better directional uniformity than the converging beam 402. The collimated converging light beam 403 is subsequently received by an optical sensor to form a fingerprint image. The collimated converging light beam 403 collected by the optical sensor has good directional consistency, which helps to improve the quality of the formed fingerprint image.

In this embodiment, the light-shielding layer 230 is made of a black light-absorbing material.

An optical sensor 300 is provided, and the optical sensor 300 receives the collimated converging light beam 403 output by the collimator 200 to form a fingerprint image.

In this embodiment, the optical sensor 300 includes a plurality of photosensitive pixel units, which correspond to the light-transmitting pillars 220 and are adapted to receive the collimated converging light beam 403 transmitted by the corresponding light-transmitting pillars 220.

In this embodiment, the optical sensor 300 is a CMOS optical sensor. In other embodiments, the optical sensor 300 may also be a TFT process based optical sensor.

In this embodiment, before the optical sensor 300 is used to receive the collimated converging light beam output by the collimator 200, the method further includes: the infrared cut-off layer 700 is used to filter out the infrared light in the collimated converging light beam output by the collimator 200.

The infrared cut-off layer 700 filters out infrared light in the collimated converging light beam, which is helpful for improving the definition of a fingerprint image, so as to improve the identification accuracy of the fingerprint identification device.

Fig. 7 to fig. 11 are schematic structural diagrams corresponding to steps in an embodiment of a forming method of the present invention.

The present invention also provides a method for forming the fingerprint recognition device, which is described in detail below with reference to fig. 7 to 11.

Referring to fig. 7, a collimator 200 is provided, the collimator 200 comprising a plurality of collimating units 210 arranged in parallel; a photoresist layer 500 is formed on top of the collimator 200.

In this embodiment, the photoresist layer 500 covers the top surface of each of the collimating units 210.

Referring to fig. 8, the photoresist layer 500 is exposed; referring to fig. 9, a developing process is performed on the photoresist layer 500 after the exposure process; referring to fig. 10, the photoresist layer 500 after the development process is baked to form the convex lens group, the convex lens group includes a plurality of convex lenses 240, and each of the collimating units 210 corresponds to one of the convex lenses 240.

In this embodiment, as shown in fig. 8, in the exposure process, a plurality of exposure light sources 610 are disposed at the bottom of the collimator 200, the exposure light sources 610 emit exposure light 600, the exposure light 600 enters the collimating unit 210 from the bottom of the collimating unit 210, and exits from the top of the collimating unit 210 to expose the photoresist layer 500.

In this embodiment, on one hand, in the exposure process, the light-transmitting pillar 220 can transmit the exposure light 600, so that the photoresist layer 500 covering the top of the light-transmitting pillar 220 is irradiated by the exposure light 600, and then the convex lens 240 is formed through the developing process and the baking process. On the other hand, in the exposure process, since the exposure light 600 is absorbed by the light shielding layer 230 when the exposure light 600 is irradiated onto the light shielding layer 230 during the transmission process, the photoresist layer 500 covering the top of the light shielding layer 230 is difficult to be irradiated by the exposure light 600, and therefore, the photoresist layer 500 covering the top of the light shielding layer 230 is easily washed away by the developing solution during the subsequent developing process, and a space is formed between the adjacent convex lenses 240.

In the baking process, the photoresist layer 500 material can be redistributed, so that the surface of the convex lens 240 can be formed smoothly by controlling the temperature of the baking process, which is helpful for improving the light gathering effect of the convex lens 240.

Referring to fig. 11, a touch screen 100 is provided, where the touch screen 100 includes a sensing surface 101 and a light emitting unit 103, and the touch screen 100 is disposed on the convex lens group.

In this embodiment, the method further includes: providing an optical sensor 300, the collimator 200 being arranged on the optical sensor 300; an infrared cut-off layer 700 is provided, the infrared cut-off layer 700 being located between the collimator 200 and the optical sensor 300.

In this embodiment, the infrared cut-off layer 700 is formed at the bottom of the collimator 200 by a sputtering process. In other embodiments, the infrared cut layer 700 may be formed on the bottom of the collimator 200 by using an evaporation coating process or a coating process.

In this embodiment, the infrared cut-off layer 700 and the optical sensor 300 are bonded by a first optical adhesive 810. The first optical cement 810 is made of OCA (optically Clear adhesive). In other embodiments, the first optical glue 810 material is OCR (optical Clear resin) or DAF (die attach film).

In another embodiment, the infrared cut-off layer is formed on the top of the optical sensor by a sputtering coating process, an evaporation coating process or a coating process, and the infrared cut-off layer and the collimator are bonded by optical cement.

Referring to fig. 12 to 16, a forming method of another embodiment will be described in detail.

Referring to fig. 12, a collimator 200 is provided, the collimator 200 comprising a plurality of collimating units 210 arranged in parallel; a light-transmitting layer 510 covering the top surface of the collimator 200 is formed, and the photoresist layer 500 covering the surface of the light-transmitting layer 510 is formed.

In the subsequent exposure process, the exposure light is incident from the bottom of the collimating unit 210 and exits from the top of the collimating unit 210, and the light-transmitting layer 510 can transmit the exposure light, so that a part of the exposure light can irradiate the photoresist layer 500 above the light-shielding layer 230.

Referring to fig. 13, the photoresist layer 500 is exposed; referring to fig. 14, a developing process is performed on the photoresist layer 500 after the exposure process; referring to fig. 15, the photoresist layer 500 after the development process is baked to form the convex lens group, the convex lens group includes a plurality of convex lenses 240, and each of the collimating units 210 corresponds to one of the convex lenses 240.

In this embodiment, as shown in fig. 13, in the exposure process, a plurality of exposure light sources 610 are disposed at the bottom of the collimator 200, the exposure light sources 610 emit exposure light 600, the exposure light 600 enters the collimating unit 210 from the bottom of the collimating unit 210, and exits from the top of the light-transmitting layer 510 through the top of the collimating unit 210 to expose the photoresist layer 500.

In this embodiment, since a portion of the exposure light 600 emitted from the top of the light-transmitting pillar 220 has a certain inclination angle, during the transmission process in the light-transmitting layer 510, the inclination angle of the exposure light 600 is not changed, and the exposure light may be emitted from the top of the light-transmitting layer 510 covering the light-shielding layer 230, so that the photoresist layer 500 at the corresponding position is irradiated by the exposure light 600, which is helpful for reducing the distance between adjacent convex lenses 240, and the formed convex lenses 240 are closely arranged.

Referring to fig. 16, a touch screen 100 is provided, where the touch screen 100 includes a sensing surface 101 and a light emitting unit 103, and the touch screen 100 is disposed on the convex lens group.

In this embodiment, the infrared cut-off layer 700 is formed on the top of the optical sensor 300 by a coating process. In other embodiments, the infrared cut-off layer 700 may be formed on top of the optical sensor 300 by using an evaporation coating process or a sputtering coating process.

In this embodiment, the infrared cut-off layer 700 and the collimator 200 are bonded by a second optical adhesive 820. The second optical cement 820 is made of OCA. In other embodiments, the second optical glue 820 material is OCR or DAF.

In another embodiment, the infrared cut-off layer is formed on the bottom of the collimator by a sputtering coating process, an evaporation coating process or a coating process, and the infrared cut-off layer and the optical sensor are bonded by using an optical adhesive.

Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be effected therein by one of ordinary skill in the pertinent art without departing from the scope or spirit of the present invention, and the scope of the present invention is defined by the appended claims.

Claims

1. A fingerprint recognition device, comprising:

the touch screen comprises a sensing surface and a light-emitting unit, wherein the light-emitting unit emits light rays which form reflected light through the sensing surface and are output;

a convex lens group including a plurality of convex lenses, each of the convex lenses receiving the reflected light to converge to form a converging light beam;

and the collimator comprises a plurality of collimation units which are arranged in parallel, each collimation unit corresponds to the convex lens one by one, and each collimation unit receives the convergent light beam output by the corresponding convex lens and collimates to form a collimated convergent light beam.

2. The fingerprint recognition device according to claim 1, wherein said collimating unit comprises a light-transmitting pillar and a light-shielding layer, said light-shielding layer covers a sidewall surface of said light-transmitting pillar, said convex lens covers a top surface of said light-transmitting pillar, and said convex lens is located between said touch screen and said collimating unit.

3. The fingerprint recognition device of claim 1, further comprising: and the optical sensor receives the collimated convergent light beam output by the collimator to form a fingerprint image.

4. The fingerprint recognition device of claim 3, further comprising: an infrared cut-off layer located between the collimator and the optical sensor.

5. The fingerprint recognition device of claim 3, wherein said optical sensor comprises a plurality of light-sensitive pixel cells, said light-sensitive pixel cells being in one-to-one correspondence with said collimating cells.

6. The fingerprint recognition device of claim 1, wherein the convex lens has a refractive index greater than 1.4 and less than 1.5.

7. The fingerprint recognition device of claim 6, wherein the height of the convex lens is greater than 3 μm and less than 30 μm.

8. The fingerprint recognition device of claim 2, wherein said light-transmitting cylinder is cylindrical or prismatic.

9. The fingerprint recognition device of claim 8, wherein the light-transmitting cylinder has a height to base diameter ratio greater than 10 when the light-transmitting cylinder is cylindrical.

10. The fingerprint identification device of claim 2, wherein the light blocking layer has a thickness greater than 0.5 μm.

11. The fingerprint identification device of claim 2, wherein the plurality of collimating elements are arranged in an array, and the light shielding layers of adjacent collimating elements are in contact.

12. The fingerprint recognition device of claim 1, further comprising: and the euphotic layer is arranged between the collimator and the convex lens group.