Optical fingerprint module and electronic device

Abstract

The application provides an optical fingerprint module and an electronic device, and relates to the technical field of biometric identification. A plurality of imaging devices arranged in an array are used to partition and individually image a fingerprint collection area on a display screen, and then the complete target feature in the fingerprint collection area is obtained through splicing. Compared with a scheme of using one large imaging device to realize imaging, miniaturization and thinning can be realized, and the magnification of the plurality of imaging devices as a whole is less than 1, so that the size of the image sensor is smaller when realizing an equivalent area of the fingerprint collection area.

Description

Technical Field

[0001] This application relates to the field of biometric technology, and more specifically, to an optical fingerprint module and an electronic device. Background Technology

[0002] With the development of portable terminal devices, such as mobile phones, the application of biometric technology is becoming increasingly widespread and in-depth. Taking electronic devices as an example, fingerprint recognition, fingerprint verification, and facial recognition are increasingly used in screen wake-up of display devices and identity authentication steps in various programs, improving the security of display devices and the flexibility of their use.

[0003] Currently, the solutions used for under-display optical fingerprint imaging can be divided into two categories according to module thickness: ultra-thin and lens-type. Among them, the lens-type solution has a thicker module thickness, which cannot meet the current demand for thinner and lighter terminal devices. Although the ultra-thin solution can reduce the module thickness, it requires the image sensor to be large enough to achieve large-area imaging, which is not conducive to the miniaturization of the module. Summary of the Invention

[0004] The purpose of this application is to provide an optical fingerprint module and electronic device in order to address the shortcomings of the prior art.

[0005] To achieve the above objectives, the technical solutions adopted in the embodiments of this application are as follows: In one aspect of this application, an optical fingerprint module is provided for being configured below a display screen. The optical fingerprint module includes an image sensor and an optical array structure located between the image sensor and the display screen. The optical array structure includes a plurality of imaging devices arranged in an array. The object plane area of ​​each imaging device is located in the fingerprint acquisition area of ​​the display screen, and the image plane area of ​​each imaging device is located in the imaging plane of the image sensor. The magnification of the optical array structure is less than 1.

[0006] Optionally, at least some of the imaging devices may have a magnification of less than 1.

[0007] Optionally, at least part of the optical axis of the imaging device is tilted toward the center of the imaging surface of the image sensor.

[0008] Optionally, in at least some imaging devices, the optical axis tilt angles of imaging devices with equal distances from the optical center to the center of the optical array structure are the same.

[0009] Optionally, in at least some imaging devices, the tilt angle of the optical axis of the imaging device is positively correlated with the distance from the optical center of the imaging device to the center of the optical array structure.

[0010] Optionally, in at least some imaging devices, the imaging device with the optical axis tilted toward the center of the imaging surface of the image sensor has at least one surface that is a freeform surface.

[0011] Optionally, multiple imaging devices are arranged in a first matrix of M rows × N columns. When both M and N are odd numbers, the multiple imaging devices include a central imaging device and multiple peripheral imaging devices distributed around the central imaging device. The optical axes of the multiple peripheral imaging devices are tilted toward the center of the imaging surface of the image sensor, and the optical axis of the central imaging device passes through the center of the imaging surface of the image sensor and is perpendicular to the imaging surface of the image sensor.

[0012] Optionally, multiple imaging devices are arranged in a first matrix of M rows × N columns. When M or N is an even number, the optical axes of the multiple imaging devices are all tilted toward the center of the imaging surface of the image sensor.

[0013] Optionally, the optical axes of multiple imaging devices are parallel to each other and all perpendicular to the imaging surface of the image sensor.

[0014] Optionally, multiple imaging devices may have the same surface shape.

[0015] Optionally, multiple object surface regions are arranged in a second matrix, and each object surface region is circular; the second matrix satisfies: L≤ Where L is the center-to-center distance between two adjacent object surface regions in the row or column direction, and D is the diameter of the object surface region.

[0016] Optionally, multiple image plane regions are arranged in a third matrix, and each image plane region is circular; the third matrix satisfies: D'≤L', and L≥L', where L' is the center distance between two adjacent image plane regions in the row or column direction, and D' is the diameter of the image plane region.

[0017] Optionally, multiple object surface regions are arranged in a fourth matrix, and each object surface region is a rectangle; the fourth matrix satisfies: X≤W, Y≤H, where X is the center distance between two adjacent object surface regions in the row direction, W is the side length of the object surface region in the row direction, Y is the center distance between two adjacent object surface regions in the column direction, and H is the side length of the object surface region in the column direction.

[0018] Optionally, multiple image plane regions are arranged in a fifth matrix, and each image plane region is a rectangle; the fifth matrix satisfies: X'≥W', Y'≥H', and X≥X', Y≥Y', where X' is the center distance between two adjacent image plane regions in the row direction, W' is the side length of the image plane region in the row direction, Y' is the center distance between two adjacent image plane regions in the column direction, and H' is the side length of the image plane region in the column direction.

[0019] Optionally, every two adjacent image plane regions are joined together to form a first image plane region, which coincides with the imaging plane of the image sensor.

[0020] Optionally, the magnification of the optical array structure is less than or equal to 1 / 5.

[0021] Optionally, the imaging device is a lens, or the imaging device is a microlens, the size of which is less than 100 μm.

[0022] Optionally, when the imaging device is a microlens, a light-shielding layer is provided on the imaging surface of the image sensor, and an optical array structure is provided on the side surface of the light-shielding layer away from the image sensor. The light-shielding layer has multiple light-transmitting channels corresponding to multiple imaging devices.

[0023] In another aspect of this application, an electronic device is provided, including a display screen and any of the above-described optical fingerprint modules, wherein the optical fingerprint module is disposed below the display screen.

[0024] The beneficial effects of this application include: This application provides an optical fingerprint module and electronic device. By using multiple imaging devices arranged in an array to image the fingerprint collection area on the display screen in separate sections, and then stitching them together to obtain the complete target features within the fingerprint collection area, this method can achieve miniaturization and thinning compared to using a large imaging device. At the same time, the overall magnification of the multiple imaging devices is less than 1, so that the size of the image sensor is smaller when achieving the same fingerprint collection area. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application; Figure 2 A schematic diagram of a first surface area and a fingerprint collection area provided in an embodiment of this application; Figure 3 This is a schematic diagram of the structure of another electronic device provided in an embodiment of this application; Figure 4 A schematic diagram of another optical array structure provided in the embodiments of this application; Figure 5 A schematic diagram of another object surface area and fingerprint collection area provided in an embodiment of this application; Figure 6 A schematic diagram of another image plane region and imaging plane provided for an embodiment of this application; Figure 7 This is a schematic diagram of the structure of another electronic device provided in an embodiment of this application; Figure 8 A schematic diagram of yet another optical array structure provided in the embodiments of this application; Figure 9 A schematic diagram of another object surface area and fingerprint collection area provided in an embodiment of this application; Figure 10 A schematic diagram illustrating yet another image plane region and imaging plane provided in an embodiment of this application; Figure 11 A schematic diagram of another optical array structure provided in the embodiments of this application; Figure 12 A schematic diagram of another object surface area and fingerprint collection area provided in an embodiment of this application; Figure 13 A schematic diagram illustrating another image plane region and imaging plane provided in an embodiment of this application; Figure 14 A schematic diagram of the structure of another electronic device provided in this application embodiment; Figure 15 This is a schematic diagram of a rectangular object surface area and a fingerprint collection area provided in an embodiment of this application; Figure 16 A schematic diagram of a rectangular image area and an imaging plane provided in an embodiment of this application; Figure 17 This is a schematic diagram of the structure of an electronic device with a microlens provided in an embodiment of this application.

[0027] Icons: 110 - Display screen; 111 - Fingerprint collection area; 120 - Image sensor; 121 - Imaging surface; 130 - Light-shielding layer; 131 - Light transmission channel; 200 - Optical array structure; 210 - Imaging device; 211 - Central imaging device; 212 - Peripheral imaging device; 220 - Object plane area; 230 - Image plane area; 240 - First object plane area; 40 - Optical axis. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. It should be noted that, in the absence of conflict, the various features in the embodiments of this application can be combined with each other, and the combined embodiments are still within the protection scope of this application.

[0029] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of describing this application and simplifying the description, and therefore should not be construed as limiting this application. In addition, the terms "first," "second," and "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0030] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two devices. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0031] One aspect of this application provides an optical fingerprint module that uses multiple imaging devices arranged in an array to image the fingerprint collection area on the display screen in separate sections. Then, the complete target features within the fingerprint collection area are obtained by stitching the images together. Compared with the scheme of using a large imaging device to achieve imaging, this method can achieve miniaturization and thinning. At the same time, the overall magnification of the multiple imaging devices is less than 1, so that the size of the image sensor is smaller when achieving the same fingerprint collection area. The embodiments of this application will be described below with reference to the accompanying drawings.

[0032] Please refer to Figure 1 The optical fingerprint module can be configured below the display screen 110 so that when a target object comes into contact with the fingerprint collection area 111 on the surface of the display screen 110, the light beam reflected by the target object is received by the optical fingerprint module, thereby enabling the optical fingerprint module to collect features of the target object. It should be understood that the target object can be a finger, palm, human eye, face, etc. Therefore, the features of the target object include, but are not limited to, fingerprint features, palm print features, finger vein features, iris features, facial features, etc.

[0033] Please continue to refer to Figure 1 The optical fingerprint module includes an image sensor 120 and an optical array structure 200. The optical array structure 200 is located between the image sensor 120 and the display screen 110 so that the light beam reflected by the target object is first shaped by the optical array structure 200 and then imaged on the imaging surface 121 of the image sensor 120.

[0034] The optical array structure 200 includes multiple imaging devices 210 arranged in an array. Each imaging device 210 has an object-side surface region 220 and an image-side surface region 230. To achieve accurate information acquisition, the object-side surface region 220 of each imaging device 210 is at least partially located within the fingerprint acquisition area 111 of the display screen 110, and the image-side surface region 230 of each imaging device 210 is located within the imaging surface 121 of the image sensor 120. Thus, when a target object comes into contact with the fingerprint acquisition area 111, each imaging device 210 will image its corresponding object-side surface region 220 onto its corresponding image-side surface region 230, so that it can be received by the image sensor 120 to complete the feature acquisition of the target object. Since the optical array structure 200 uses multiple small imaging devices, compared to using only one large imaging device, the small imaging devices can shorten their distance to the display screen, thereby achieving a thinner and lighter design. Based on this, and with the magnification of the optical array structure 200 being less than 1, the image sensor 120 is smaller in size while maintaining the same area of ​​fingerprint acquisition region 111. It should be understood that the magnification of the optical array structure 200 refers to the ratio of the image height of the optical array structure 200 (i.e., the size of the image of the object being measured) to the object height of the optical array structure 200 (i.e., the size of the object being measured).

[0035] To ensure that every position in the fingerprint acquisition area 111 can be imaged on the imaging surface 121 of the image sensor 120, the object surface areas 220 corresponding to all imaging devices 210 can be combined and stitched together to form a total object surface area (hereinafter referred to as the first object surface area 240), and the first object surface area 240 completely covers the fingerprint acquisition area 111. For example Figure 2 As shown, the first surface region 240 covers the fingerprint acquisition region 111, and its area is larger than that of the fingerprint acquisition region 111; or, for example, the first surface region 240 covers the fingerprint acquisition region 111, and its area is equal to that of the fingerprint acquisition region 111. It should be understood that... Figure 2 The first object surface region 240 and the fingerprint acquisition region 111 shown are both rectangular in shape, but this application does not limit the shape of the two or whether their shapes are the same. For example, the shape of the first object surface region 240 can be a polygon, a circle, an ellipse, or an irregular shape, etc., and the same applies to the fingerprint acquisition region 111. Furthermore, the shape of the first object surface region 240 can be the same as or different from that of the fingerprint acquisition region 111 (e.g., Figure 5 As shown, the first surface area 240 is an irregular shape composed of multiple circular surface areas 220, and the fingerprint collection area 111 is rectangular. As long as the first surface area 240 can completely cover the fingerprint collection area 111, it is acceptable.

[0036] Based on this, in order to ensure that the pixels on the imaging surface 121 of the image sensor 120 can accurately image the image area 230 of each imaging device 210, the imaging surface 121 can completely cover all image areas 230, and any two adjacent image areas 230 can have a gap or be exactly adjacent to each other, avoiding the situation where adjacent image areas 230 share the same pixel for imaging. For example Figure 6 As shown, multiple image plane regions 230 are spaced apart from each other, and all image plane regions 230 are located within the imaging plane 121.

[0037] Optionally, to achieve a magnification of less than 1 for the optical array structure 200, the magnification of all imaging devices 210 can be less than 1. In other words, the area of ​​the object plane region 220 of each imaging device 210 is larger than the area of ​​its image plane region 230. Of course, in other embodiments, the magnification of some imaging devices 210 can be less than 1, while the magnification of the remaining imaging devices 210 can be equal to or greater than 1, as long as the overall magnification of the optical array structure 200 is less than 1.

[0038] Optionally, the magnification of the optical array structure 200 is less than or equal to 1 / 5, which helps to obtain a thinner module and effectively reduces the size of the image sensor 120.

[0039] When multiple imaging devices 210 are set up, the optical axes 40 of any two imaging devices 210 can be parallel to each other, and the optical axis 40 of each imaging device 210 can be vertically perpendicular to the imaging surface 121 of the image sensor 120, such as... Figure 1 As shown, three imaging devices 210 are illustrated, and the optical axis 40 of each imaging device 210 is perpendicular to the imaging surface 121 of the image sensor 120. Thus, the optical axes 40 of any pair of imaging devices 210 are parallel to each other, which can reduce the thickness to a certain extent and decrease the size of the image sensor 120. Furthermore, the surface shapes of the multiple imaging devices 210 can be identical; that is, the incident and exit surfaces of any two imaging devices 210 can have the same shape.

[0040] Continue to combine Figure 1 It can be seen that, in order to ensure that adjacent image plane regions 230 do not overlap, if the size of the image sensor 120 is to be small, the overlapping area of ​​adjacent object plane regions 220 will be relatively large. Therefore, the area of ​​the first object plane region 240 is a smaller proportion of the total area of ​​all object plane regions 220, which is not conducive to obtaining a larger first object plane region 240 when the size of the image sensor 120 is small.

[0041] If it is necessary to obtain a larger first object plane region 240 while keeping the size of the image sensor 120 unchanged, or to obtain a larger first object plane region 240 while reducing the size of the image sensor 120, the optical axes 40 of at least a portion of the imaging devices 210 can be tilted toward the center of the imaging surface 121 of the image sensor 120. In other words, the optical axes 40 of at least a portion of the imaging devices 210 are tilted toward the center of the imaging surface 121 of the image sensor 120 along the beam receiving direction. As a result, for the image plane region 230, the image plane region 230 corresponding to the part of the image sensor 120 with tilted optical axes 40 will be more concentrated around the center of the imaging surface 121, reducing the distance between them. This reduces the required imaging surface 121, thereby reducing the size of the image sensor 120. For the object surface region 220, the optical axis 40 of the imaging device 210 will diverge outwards relative to the center of the fingerprint acquisition region 111. This causes the object surface region 220 corresponding to the imaging device 210 to diverge outwards from the center of the fingerprint acquisition region 111. While ensuring that the first object surface region 240 fully covers the fingerprint acquisition region 111, the divergence effect is used as much as possible to reduce the overlap area of ​​adjacent object surface regions 220, thereby increasing the proportion of the area of ​​the first object surface region 240 to the total area of ​​all object surface regions 220, thus expanding the area of ​​the first object surface region 240.

[0042] For example, in the optical array structure 200, the optical axis 40 of a portion of the imaging devices 210 is tilted, while the optical axis 40 of a portion of the imaging devices 210 is not tilted, for example... Figures 3 to 6 As shown, the nine imaging devices 210 are arranged in a first matrix of M rows × N columns, where, as Figure 4 As shown, both M and N are odd numbers equal to 3. Therefore, the nine imaging devices 210 include a central imaging device 211 and eight peripheral imaging devices 212 distributed around the central imaging device 211. The optical axes 40 of the eight peripheral imaging devices 212 are inclined toward the center of the imaging surface 121 of the image sensor 120, that is, the optical axes 40 of the eight peripheral imaging devices 212 gradually converge from the display screen 110 to the image sensor 120. Figure 3The second row shows three imaging devices 210 (including a central imaging device 211 and two peripheral imaging devices 212 distributed on the left and right). The optical axis 40 of the central imaging device 211 passes through the center of the imaging surface 121 of the image sensor 120 and is perpendicular to the imaging surface 121 of the image sensor 120. The optical axes 40 of the peripheral imaging devices 212 on the left and right sides can be tilted towards the center of the imaging surface 121 at a certain angle. That is, the ends of the optical axes 40 closer to the image sensor 120 are close to each other, and the ends of the optical axes 40 farther away from the image sensor 120 are diverging. For the image plane region 230: the eight image plane regions 230 move closer to the center of the imaging surface 121 to reduce the distance between the eight image plane regions 230 and the middle image plane region 230, thereby reducing the size of the imaging surface 121. For the object plane region 220: the eight object plane regions 220 diverge outwards in a ring shape, thereby reducing the area of ​​intersection between the eight object plane regions 220 and the middle object plane region 220, and expanding the first object plane region 240. It should be understood that in other implementations, M may be equal to or not equal to N, and M and N may also be equal to odd numbers such as 5, 7 or 9, which can be set with reference to the first 3×3 matrix.

[0043] For example, the optical axes 40 of all imaging devices 210 in the optical array structure 200 are tilted, that is, the multiple imaging devices 210 are arranged in a first matrix of M rows × N columns. When M or N is an even number, the optical axes 40 of the multiple imaging devices 210 can be tilted toward the center of the imaging surface 121 of the image sensor 120.

[0044] In one embodiment, such as Figures 7 to 10 As shown, both M and N are even numbers equal to 2. Therefore, the optical array structure 200 includes four imaging devices 210 arranged in a 2×2 first matrix. The optical axes 40 of the four imaging devices 210 are all tilted towards the center of the image sensor 120, that is, the optical axes 40 of the four imaging devices 210 gradually converge from the display screen 110 to the image sensor 120. Figure 7 Two imaging devices 210 are shown in the first row, second row, first column, or second column, with their optical axes 40 tilted toward the center of the image sensor 120. Therefore, for the image plane region 230: the four image plane regions 230 converge toward the center of the imaging plane 121 to reduce the spacing between them, thus reducing the size of the imaging plane 121; for the object plane region 220: the four object plane regions 220 diverge outwards, thereby reducing the area of ​​intersection between them and expanding the first object plane region 240.

[0045] In one embodiment, such as Figures 11 to 13As shown, M is an even number equal to 2 and N is an odd number equal to 3. Therefore, the optical array structure 200 includes six imaging devices 210 arranged in a first matrix of 2×3. The optical axes 40 of the six imaging devices 210 are all tilted toward the center of the image sensor 120. That is, the optical axes 40 of the six imaging devices 210 gradually converge from the display screen 110 to the image sensor 120. For the image plane region 230, the six image plane regions 230 move toward the center of the imaging plane 121 to reduce the distance between the image plane regions 230 and reduce the size of the imaging plane 121. For the object plane region 220, the six object plane regions 220 diverge in all directions to reduce the area of ​​intersection of the object plane regions 220 and expand the first object plane region 240.

[0046] Optionally, among all imaging devices 210 whose optical axis 40 is tilted toward the center of the imaging surface 121, the tilt angle of the optical axis 40 of the imaging device 210 is positively correlated with the distance from the optical center of the imaging device 210 to the center of the optical array structure 200. In other words, the farther the optical center of the imaging device 210 is from the center of the optical array structure 200, the greater the tilt angle of the optical axis 40 of the imaging device 210. This is to facilitate a greater divergence effect in the object plane region 220 of the imaging device 210 that is farther from the center of the optical array structure 200, which is beneficial to obtaining a larger first object plane region 240.

[0047] Specifically, for example Figure 14 As shown, five imaging devices 210 are illustrated, from left to right: the first imaging device, the second imaging device, and the fifth imaging device. The third imaging device is the central imaging device 211, so its optical center can be considered the center of the optical array structure 200. The optical axis 40 of the third imaging device is perpendicular to the imaging surface 121, and their intersection is the center of the imaging surface 121. The optical axes 40 of the first, second, fourth, and fifth imaging devices are tilted towards the center of the image sensor 120. Therefore, the tilt angles of the optical axes 40 of the first, second, fourth, and fifth imaging devices can be referenced to the optical axis 40 of the third imaging device. Taking the fourth and fifth imaging devices as examples: the distance from the optical center of the fifth imaging device to the optical center of the third imaging device is greater than the distance from the optical center of the fourth imaging device to the optical center of the third imaging device. Therefore, the tilt angle θ2 of the optical axis 40 of the fifth imaging device is greater than the tilt angle θ1 of the optical axis 40 of the fourth imaging device. The same applies to the first and second imaging devices.

[0048] Optionally, among all imaging devices 210 whose optical axis 40 is tilted toward the center of the imaging surface 121, the imaging devices 210 whose optical center is equidistant from the center of the optical array structure 200 have the same tilt angle of the optical axis 40. This helps to make the object surface region 220 diverge in all directions to expand the first object surface region 240. The object surface region 220 corresponding to the imaging devices 210 whose optical center is equidistant from the center of the optical array structure 200 diverges in all directions to obtain a more regular and uniform first object surface region 240, which is beneficial for the acquisition of fingerprint images in actual use.

[0049] Specifically, such as Figure 3 and Figure 4 As shown, the optical axes 40 of the eight peripheral imaging devices 212 located around the central imaging device 211 have the same tilt angle, which makes the object surface region 220 corresponding to the eight peripheral imaging devices 212 diverge in all directions to the same degree.

[0050] Specifically, such as Figure 7 and Figure 8 As shown, the optical axes 40 of the four imaging devices 210 are tilted at the same angle, which makes the object plane regions 220 corresponding to the four peripheral imaging devices 212 diverge in all directions to the same degree.

[0051] Specifically, such as Figure 11 As shown, the two imaging devices 210 in the second column have the same optical axis 40 tilt angle, and the four imaging devices 210 in the first and third columns have the same optical axis 40 tilt angle.

[0052] Specifically, such as Figure 14 As shown, the second imaging device 210 and the fourth imaging device 210 have the same optical axis 40 tilt angle, and the first imaging device 210 and the fifth imaging device 210 have the same optical axis 40 tilt angle.

[0053] By setting freeform surfaces or adjusting the angle of imaging device 210, the optical axis 40 of imaging device 210 can be tilted. When achieved through freeform surfaces, the surface shape of all imaging devices 210 tilted towards the center of imaging surface 121 is a freeform surface. Specifically, at least one surface of imaging device 210 can be a freeform surface. For example, the light-emitting surface and / or the light-incident surface of imaging device 210 can be a freeform surface, or a surface between the light-emitting surface and the light-incident surface can be a freeform surface. The remaining surfaces of imaging device 210 can be planes, spheres, aspherical surfaces, etc., where the freeform surface can satisfy the following equation:

[0054] in, c is the radius of curvature at the vertex of the spherical surface, and k is the conic coefficient. Let m and n be the coefficients of the polynomial XY, where m and n are non-negative integers and satisfy m+n≥1.

[0055] When multiple imaging devices 210 are arranged in an array, in order for the first object surface area 240 to fully cover the fingerprint collection area 111 of the display screen 110, two adjacent object surface areas 220 should be adjacent (meaning they do not overlap but their edges are connected) and / or overlap. For ease of understanding, the following will provide an illustrative explanation.

[0056] In some implementations, a first surface region 240 can be formed by any two adjacent surface regions 220, and the first surface region 240 can cover the fingerprint acquisition region 111. For example... Figure 15 As shown, nine rectangular surface regions 220 are depicted, with their edges adjacent to each other. These nine rectangular surface regions 220 are then joined to form a first rectangular surface region 240. Simultaneously, the fingerprint acquisition region 111 is also rectangular, allowing the first surface region 240 to fully cover and overlap the fingerprint acquisition region 111 (i.e., both have the same area and shape). Of course, while the first surface region 240 is rectangular, the fingerprint acquisition region 111 can be any shape, such as circular or triangular.

[0057] When the adjacency of surface regions 220 cannot fully cover the fingerprint acquisition area 111, the first surface region 240 can effectively cover the fingerprint acquisition area 111 by overlapping surface regions 220. When overlapping surface regions 220 occur: some surface regions 220 overlap while others do not; or each surface region 220 may overlap with another surface region 220. For example... Figure 5 , Figure 9 or Figure 12 As shown, each object surface region 220 is circular, and each object surface region 220 has overlapping regions that overlap with its adjacent object surface regions 220 and non-overlapping regions that do not overlap with its adjacent object surface regions 220, for example... Figure 5 The object surface region 220 in the upper left corner has overlapping regions b with the horizontally adjacent object surface regions 220 and the vertically adjacent object surface regions 220 respectively. At the same time, it also has non-overlapping regions a that do not overlap with other object surface regions 220. Thus, the overlapping regions b can be used to avoid omissions between adjacent object surface regions 220, and the non-overlapping regions a can be used to ensure that each object surface region 220 has its own exclusive area, so that different parts of the target object can be imaged in sections. The combination of overlapping regions b and non-overlapping regions a can achieve full coverage of the fingerprint acquisition area 111.

[0058] When all object surface regions 220 are circular and arranged in a second matrix, such as Figure 5 , Figure 9 or Figure 12 As shown, to avoid omissions between adjacent object surface regions 220, the second matrix can satisfy: L≤ Where L is the center-to-center distance between two adjacent surface regions 220 in the row or column direction, and D is the diameter of the surface region 220. This ensures that multiple surface regions 220 overlap to fully cover the entire fingerprint acquisition area 111. When L = At the same time, it can achieve full coverage of the square fingerprint collection area 111 with minimal overlap, thereby making full use of the surface area 220.

[0059] When all image plane regions 230 are circular and arranged in a third matrix, such as Figure 6 , Figure 10 or Figure 13 As shown, the third matrix satisfies: D'≤L', and L≥L', where L' is the center-to-center distance between two adjacent image plane regions 230 in the row or column direction, and D' is the diameter of the image plane region 230. This is to achieve a smaller size for the image sensor 120 and a larger area for the fingerprint acquisition region 111, i.e., to achieve a magnification of less than 1 for the optical fingerprint module.

[0060] It should be understood that when L=L', that is, the optical axes 40 of any two imaging devices 210 are parallel to each other, and the optical axis 40 of each imaging device 210 can be vertically perpendicular to the imaging surface 121 of the image sensor 120. Therefore, the surface shape of each imaging device 210 is the same, that is, the surface shape of each imaging device 210 can adopt the same design.

[0061] When L > L', at least some of the imaging devices 210 have their optical axes 40 tilted toward the center of the image sensor 120, which helps to further reduce the size of the image sensor 120 and increase the area of ​​the first object surface region 240. For example Figures 3 to 6 The optical axis 40 of the central imaging device 211 shown is not tilted, while the optical axis 40 of the peripheral imaging device 212 is tilted. Therefore, the surface shape of the central imaging device 211 is different from that of the peripheral imaging device 212; for example, 7 to Figure 10 or Figures 11 to 13 The optical axis 40 of all the imaging devices 210 shown is tilted.

[0062] Optional, such as Figure 15As shown, multiple object surface regions 220 are arranged in a fourth matrix, each object surface region 220 being a rectangle. The fourth matrix satisfies: X ≤ W, Y ≤ H, where X is the center-to-center distance between two adjacent object surface regions 220 in the row direction, W is the side length of object surface region 220 in the row direction, Y is the center-to-center distance between two adjacent object surface regions 220 in the column direction, and H is the side length of object surface region 220 in the column direction. When X < W, adjacent object surface regions 220 in the row direction will overlap; when Y < H, adjacent object surface regions 220 in the column direction will overlap. When X = W, adjacent object surface regions 220 in the row direction are exactly adjacent; when Y = H, adjacent object surface regions 220 in the column direction are exactly adjacent, in order to make full use of the object surface regions 220.

[0063] Optional, such as Figure 16 As shown, multiple image plane regions 230 are arranged in a fifth matrix, each image plane region 230 being a rectangle. The fifth matrix satisfies: X'≥W', Y'≥H', and X≥X', Y≥Y', where X' is the center-to-center distance between two adjacent image plane regions 230 in the row direction, W' is the side length of image plane region 230 in the row direction, Y' is the center-to-center distance between two adjacent image plane regions 230 in the column direction, and H' is the side length of image plane region 230 in the column direction. When X'>W', adjacent image plane regions 230 in the row direction will not overlap; when Y'>H', adjacent image plane regions 230 in the column direction will not overlap. When X'=W', adjacent image plane regions 230 in the row direction are exactly adjacent; when Y'=H', adjacent image plane regions 230 in the column direction are exactly adjacent, in order to make full use of the image plane regions 230.

[0064] Optional, such as Figure 16 As shown, all image plane regions 230 are adjacent to each other to form a first image plane region 230. The first image plane region 230 coincides with the imaging surface 121 of the image sensor 120. Thus, the pixels on the imaging surface 121 can be fully utilized, avoiding pixel waste.

[0065] Optionally, the imaging device 210 described above can be a lens. For example, the lens can be formed by injection molding. An imaging device 210 can include one lens, two lenses, or three lenses, etc. When the imaging device 210 is a lens, the thickness of the imaging device 210 can be reduced, and the size of the module can be reduced, such as... Figure 1 , Figure 3 , Figure 7 or Figure 14 As shown, the diameter of a single lens should be greater than 100μm, generally in the millimeter range, so that the array structure formed by multiple lenses together is the optical array structure 200. The optical array structure 200 can be detachably set in the receiving optical path of the optical fingerprint module by structural components (such as lens barrels).

[0066] Alternatively, the lens can be miniaturized to form a microlens, such as Figure 17 As shown, each imaging device 210 is a microlens, and the diameter of each microlens is less than 100 μm, typically on the micrometer scale. Multiple microlens arrays are arranged to form the aforementioned optical array structure 200. These multiple microlens arrays can be formed by molding, for example... Figure 17 As shown, to ensure the imaging effect of the microlenses, a light-shielding layer 130 can also be provided. The light-shielding layer 130 can be disposed on the imaging surface 121 of the image sensor 120. Microlenses are disposed on the upper surface of the light-shielding layer 130. At the same time, multiple light-transmitting channels 131 are provided on the light-shielding layer 130. The light-transmitting channel 131 can be a light-transmitting hole or a collimating channel, so that each microlens can be imaged on the imaging surface 121 of the image sensor 120 after passing through the light-transmitting channel 131. Furthermore, the number of light-transmitting channels 131 can correspond one-to-one with the number of microlenses, that is, one microlens is matched with one light-transmitting channel 131.

[0067] In another aspect of this application, an electronic device is provided, including a display screen 110 and any of the aforementioned optical fingerprint modules, for example... Figure 1 and Figure 2 As shown, the optical fingerprint module is located below the display screen 110 so that when identification is required, a light beam is emitted from the light-emitting element or the light-emitting layer of the display screen 110 to the fingerprint collection area 111 of the display screen 110. After being reflected by the target object, the light beam is received by the image sensor 120 after passing through the optical array structure 200, thereby realizing the collection of features.

[0068] The display screen 110 can be an Organic Light Emitting Diode (OLED) display screen 110 or a Liquid Crystal Display (LCD) display screen 110, etc. A fingerprint recognition method can be preset in this electronic device. The fingerprint recognition method typically includes steps such as fingerprint image acquisition, preprocessing, feature extraction, and feature matching. Some or all of the above steps can be implemented using traditional Computer Vision (CV) algorithms, or using deep learning algorithms based on Artificial Intelligence (AI). Fingerprint recognition technology can be applied to portable or mobile terminals such as smartphones, tablets, and gaming devices, as well as other electronic devices such as smart locks, automobiles, and bank ATMs for fingerprint unlocking, fingerprint payment, fingerprint attendance, and identity authentication.

[0069] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An optical fingerprint module, characterized in that, For mounting below a display screen, the optical fingerprint module includes an image sensor and an optical array structure located between the image sensor and the display screen. The optical array structure includes a plurality of imaging devices arranged in an array. The object plane area of ​​each imaging device is located in the fingerprint acquisition area of ​​the display screen, and the image plane area of ​​each imaging device is located in the imaging plane of the image sensor. The magnification of the optical array structure is less than 1, and the imaging devices are lenses or microlenses; at least some of the imaging devices have a magnification of less than 1. At least a portion of the optical axis of the imaging device is tilted toward the center of the imaging surface of the image sensor.

2. The optical fingerprint module as described in claim 1, characterized in that, In at least some of the imaging devices, the optical axis tilt angles of imaging devices with an optical center equidistant from the center of the optical array structure are the same.

3. The optical fingerprint module as described in claim 1, characterized in that, In at least some of the imaging devices, the tilt angle of the optical axis of the imaging device is positively correlated with the distance from the optical center of the imaging device to the center of the optical array structure.

4. The optical fingerprint module as described in claim 1, characterized in that, In at least a portion of the imaging devices, the imaging device in which the optical axis is tilted toward the center of the imaging surface of the image sensor has at least one surface that is a freeform surface.

5. The optical fingerprint module as described in any one of claims 1 to 4, characterized in that, The plurality of imaging devices are arranged in a first matrix of M rows × N columns. When both M and N are odd numbers, the plurality of imaging devices include a central imaging device and a plurality of peripheral imaging devices distributed around the central imaging device. The optical axes of the plurality of peripheral imaging devices are tilted toward the center of the imaging surface of the image sensor. The optical axis of the central imaging device passes through the center of the imaging surface of the image sensor and is perpendicular to the imaging surface of the image sensor.

6. The optical fingerprint module as described in any one of claims 1 to 4, characterized in that, The plurality of imaging devices are arranged in a first matrix of M rows × N columns. When M or N is an even number, the optical axes of the plurality of imaging devices are all tilted toward the center of the imaging surface of the image sensor.

7. The optical fingerprint module as described in claim 1, characterized in that, The optical axes of the plurality of imaging devices are parallel to each other and are all perpendicular to the imaging surface of the image sensor.

8. The optical fingerprint module as described in claim 7, characterized in that, The multiple imaging devices have the same surface shape.

9. The optical fingerprint module according to any one of claims 1 to 4, 7 and 8, characterized in that, The multiple object surface regions are arranged in a second matrix, and each object surface region is circular; The second matrix satisfies: L≤ Where L is the center-to-center distance between two adjacent object surface regions in the row or column direction, and D is the diameter of the object surface region.

10. The optical fingerprint module as described in claim 9, characterized in that, The multiple image plane regions are arranged in a third matrix, and each image plane region is circular; The third matrix satisfies: D'≤L' and L≥L', where L' is the center-to-center distance between two adjacent image plane regions in the row or column direction, and D' is the diameter of the image plane region.

11. The optical fingerprint module according to any one of claims 1 to 4, 7 and 8, characterized in that, The multiple object surface regions are arranged in a fourth matrix, and each object surface region is a rectangle; The fourth matrix satisfies: X≤W, Y≤H, where X is the center-to-center distance between two adjacent object surface regions in the row direction, W is the side length of the object surface region in the row direction, Y is the center-to-center distance between two adjacent object surface regions in the column direction, and H is the side length of the object surface region in the column direction.

12. The optical fingerprint module as described in claim 11, characterized in that, The multiple image plane regions are arranged in a fifth matrix, and each image plane region is rectangular; The fifth matrix satisfies: X'≥W', Y'≥H', and X≥X', Y≥Y', where X' is the center-to-center distance between two adjacent image plane regions in the row direction, W' is the side length of the image plane region in the row direction, Y' is the center-to-center distance between two adjacent image plane regions in the column direction, and H' is the side length of the image plane region in the column direction.

13. The optical fingerprint module according to any one of claims 1 to 4, 7 and 8, characterized in that, Each pair of adjacent image plane regions is joined together to form a first image plane region, which coincides with the imaging plane of the image sensor.

14. The optical fingerprint module according to any one of claims 1 to 4, 7 and 8, characterized in that, The magnification of the optical array structure is less than or equal to 1 / 5.

15. The optical fingerprint module according to any one of claims 1 to 4, 7 and 8, characterized in that, The size of the microlens is less than 100 μm.

16. The optical fingerprint module as described in claim 15, characterized in that, When the imaging device is a microlens, a light-shielding layer is provided on the imaging surface of the image sensor, and the optical array structure is provided on the side surface of the light-shielding layer opposite to the image sensor. The light-shielding layer has multiple light-transmitting channels corresponding to the multiple imaging devices.

17. An electronic device, characterized in that, It includes a display screen and an optical fingerprint module as described in any one of claims 1 to 16, wherein the optical fingerprint module is disposed below the display screen.

Images