Thin multi-lens optical fingerprint sensor suitable for imaging through a mobile phone display

Abstract

A multi-lens optical fingerprint reader for reading fingerprints through a display has a separator; and a plurality of microlenses having concave and convex surfaces in a microlens array, each microlens of the plurality of lenses focusing light reaching the microlens from a finger adjacent to the display, the light passing through the separator and forming an image on an associated photosensor in a photosensor array of an image sensor integrated circuit. A method of verifying a user's identity includes illuminating the user's finger with an OLED display; focusing light from the finger onto the photosensor array through the array of microlenses, reading the array to form an overlapping electronic fingerprint image; extracting features from the overlapping fingerprint image or from a stitched fingerprint image, and comparing the features with features of at least one user in a library of features associated with one or more fingers of one or more authorized users.

Description

Technical Field

[0001] The present disclosure relates to fingerprint recognition technology. In particular, the present disclosure relates to a multi-lens optical fingerprint reader adapted to read fingerprints through a display, a method of authenticating a user's identity, and a method of manufacturing a fingerprint reader. Background Art

[0002] Many modern mobile phone operating systems, including Apple iOS and Android, can be configured to use biometrics, such as fingerprints, as an alternative to a user input unlock code to authenticate the user's identity. Existing optical sensors for reading fingerprints use an electronic camera equipped with a single lens and an image sensor having a single photoelectric sensor array to image the fingerprint surface of a finger through an OLED mobile phone display. To image a reasonable area of the finger, the lens and the photoelectric sensor array are large, and a relatively large space is required between the lens and the photoelectric sensor array - which poses a problem in the limited available space of a mobile phone. Summary of the Invention

[0003] In an embodiment, a multi-lens optical fingerprint reader adapted to read fingerprints through a display includes an image sensor integrated circuit having at least one photoelectric sensor array; a partition; and a plurality of microlenses arranged in a microlens array, each microlens of the microlenses being configured to focus light reaching the microlens from a portion of a fingerprint area of a finger adjacent to the surface of the display to form an image on a plurality of photoelectric sensors associated with the microlens, the photoelectric sensors belonging to a photoelectric sensor array of the at least one photoelectric sensor array in the image sensor integrated circuit. Each microlens includes a concave element on a first side of a transparent substrate and a convex element on a second side of the transparent substrate. In a particular embodiment, for a microlens adjacent to an edge of the microlens array, the portion of the fingerprint area from which light is focused by each microlens onto the plurality of photoelectric sensors is offset in a direction away from the center of the microlens array relative to the image formed on the plurality of photoelectric sensors associated with the microlens.

[0004] In an embodiment, the multi-lens optical fingerprint reader further includes at least one light-absorbing mask layer having an opening associated with each microlens of the microlens array.

[0005] In an embodiment, the microlens array includes a microlens array of at least 1×2, at least 2×2, or at least 3×3.

[0006] In an embodiment, the multi-lens optical fingerprint reader further includes an infrared filter.

[0007] In an embodiment, a method of authenticating a user's identity includes illuminating a fingerprint area of a user's finger using an organic light emitting diode (OLED) display panel; focusing light from the fingerprint area through a microlens array onto at least one photoelectric sensor array of an integrated circuit, each microlens focusing light from a portion of the fingerprint area onto a plurality of photoelectric sensors of the at least one photoelectric sensor array; reading the at least one photoelectric sensor array to form an overlapping electronic fingerprint image; extracting features by a method selected from extracting features from the overlapping electronic fingerprint image and extracting features from a stitched image formed from the overlapping electronic fingerprint image; and comparing the features with features of at least one user in a library of features associated with one or more fingers of one or more authorized users in a memory. Each microlens includes a concave element on a first side of a transparent substrate and a convex element on a second side of the transparent substrate. In a particular embodiment, the microlenses of the microlens array and the photoelectric sensor array of the integrated circuit are configured such that the portion of the fingerprint area from which light is focused by each microlens at an edge of the microlens array onto the plurality of photoelectric sensors is offset in a direction away from the center of the microlens array.

[0008] In an embodiment, a method of manufacturing a fingerprint reader includes forming an infrared filter on a bottom side of a thin glass substrate; depositing an absorptive coating on the infrared filter; masking and etching the absorptive coating to form an opening; forming an array of concave microlens elements on the thin glass substrate by reflowing a reflowable optical material onto a top side of the thin glass substrate and shaping the reflowable optical material using a first prefabricated wafer-sized stamp; forming an array of convex microlens elements on the thin glass substrate by reflowing the reflowable optical material onto a bottom side of the thin glass substrate and shaping the reflowable material using a second prefabricated wafer-sized stamp; aligning and bonding the thin glass substrate to a spacer to form a microlens panel; aligning and bonding the microlens panel to a wafer of an integrated circuit, each integrated circuit having at least one photoelectric sensor array; dicing the wafer of the integrated circuit; and bonding the integrated circuit to a flexible printed circuit.

[0009] In an embodiment, the ratio of the radius of curvature of the concave lens surface to the radius of curvature of the convex microlens surface is greater than 10.

[0010] In an embodiment, the radius of curvature of the convex microlens surface is less than 0.5 millimeters, and the lens thickness measured between the concave microlens surface and the convex microlens surface divided by the effective focal length of the microlens is between 0.4 and 0.9.

[0011] In an embodiment, the microlens array and the at least one photoelectric sensor array are configured such that the portion of the fingerprint area from which light is focused by each microlens at an edge of the microlens array onto the plurality of photoelectric sensors is offset in a direction away from the center of the microlens array.

[0012] In an embodiment, the ratio of the total optical path length divided by the effective focal length of each microlens is between 0.5 and 2.1.

[0013] In an embodiment, the ratio of the radius of curvature of the convex lens surface divided by the effective focal length of each microlens is between 0.44 and 0.61. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a top view of an optical fingerprint sensor module and a circuit board, the optical fingerprint sensor module being configured to be placed under an OLED mobile phone display and having a 2×3 microlens array and a separator on top of an image sensor.

[0015] Figure 2 is a cross-sectional view of a finger, an OLED display, Figure 1 the optical fingerprint sensor module of Figure 1 (along line A-A in

[0016] Figure 3 is Figure 2 a magnified copy of a portion of

[0017] Figure 4 showing an overlapping field of view of an image sensor photodiode array with a traced optical path.

[0018] Figure 5 is a flowchart illustrating a method for manufacturing an optical fingerprint sensor.

[0019] Figure 6 is a block diagram of a mobile phone device in which an optical fingerprint sensor can be used.

[0020] Figure 7 is a cross-sectional view of a cost-reduced optical fingerprint sensor that images a fingerprint area as in Figures 2 to 3 a fingerprint sensor of Figures 2 to 3 while using a smaller integrated circuit than

[0021] Figure 8 is an illustration of a 3-by-3 array of microlenses, each microlens imaging a fingerprint area that is approximately the same.

[0022] Figure 9 is a flowchart illustrating a method for producing an optical fingerprint sensor.

[0023] Figure 10AA side view cross-section of the optical path from a fingerprint through a microlens to an image sensor in an embodiment. The dimensions shown are in tenths of a millimeter (mm).

[0024] Figure 10B is a top view of a microlens that can generate Figure 10A the optical path. The inner circle represents the outer edge of the recessed portion of the lower lens surface, and the outer circle represents the outer edge of the overall partition forming a conical cavity, within which a raised upper lens surface is formed.

[0025] Figure 10C is Figure 10B a cross-sectional view of the microlens, showing the lens and the integrated partition.

[0026] Figure 11A illustrates the respective layers of an alternative microlens.

[0027] Figure 11B is Figure 11A a cross-sectional view of the microlens having the respective assembled layers and having ray tracing through the microlens. Detailed Description

[0028] The fingerprint sensor module 100 ( Figure 1 ) has a microlens array 104 of microlenses 102, which is a 2×3 array in this embodiment. In other embodiments, it is contemplated that the microlens array can have other numbers of lenses, such as 3×3, 3×6, 4×4, 4×8, 5×5, 6×6, 6×8, 6×10, or larger lens arrays. The microlenses 102 of the microlens array 104 are surrounded by a black mask 106. The microlens array 104 and the black mask 106 are mounted on top of a transparent partition ( Figure 2 208 in), which is mounted on top of an image sensor integrated circuit 108. In some embodiments, the image sensor integrated circuit 108 can also include other functions, such as processor and memory functions. The image sensor integrated circuit 108 can be directly mounted to the processor printed circuit board of a mobile phone or other fingerprint-activated unit in some embodiments, or can be mounted to a flexible printed circuit 110 that extends beyond the integrated circuit 108 in other embodiments, so that it can be coupled to a connector, such as connector 202 ( Figure 2 ) attached to the processor printed circuit board 204 of a mobile phone or other fingerprint-activated or fingerprint-detection unit. The fingerprint sensor modules 100, 206 have a flexible printed circuit 110, which can be coupled to other components of the phone through connector 202.

[0029] Below the spacer 208, in a wavelength selection implementation, there may be an infrared cut-off or pass filter 210, which is omitted in other implementations. There is also an opaque black mask 212, the openings 214 of which are aligned with the photoelectric sensor array 216 of the integrated circuit 108.

[0030] In a typical application, the fingerprint sensor module 100 is positioned below the organic light-emitting diode (OLED) display panel 220 of a mobile phone. The OLED display panel 220 has a known thickness and is at least translucent to light of infrared wavelengths if there is an infrared pass filter 210, or is translucent to certain visible light wavelengths if there is an infrared cut-off filter 210.

[0031] The fingerprint sensor module 100 is typically also positioned in front of the battery 222, and the battery 222 is positioned in front of the back plate 224 of the mobile phone. The distance from the rear side of the back plate 224 to the front side of the OLED display panel 220 defines the thickness of the mobile phone.

[0032] When the user's finger 226 is positioned in contact with the front side of the OLED display panel 220, some light reflected from the fingerprint area 228 of the finger 226 passes through the OLED display panel 220 and is focused by the microlens 102 onto the photoelectric sensor array 216.

[0033] In an implementation, each microlens 102 of the lens array is an aspherical single-element lens with a total optical track length (TTL) (total optical track length, or lens total length), which is measured as the distance from the front surface of the lens to the photoelectric sensor array 216 of the integrated circuit 108. This distance is between 1.5 mm and 2.1 mm, the F-number is from 1.0 to about 1.5, the wide field of view FOV = 123°, and the effective focal length EFFL = 0.113 mm. The diameter of each lens is 0.09935 mm, and the height is 0.0526 mm.

[0034] In an implementation, the lens is defined such that the radius R1 of the front lens surface divided by the effective focal length is between 0.44 and 0.61, expressed as 0.44 < R1 (radius of the lens surface) / EFFL < 0.61. Additionally, R2 (R2 is the radius of curvature of the concave rear surface) divided by R1 (R1 is the radius of curvature of the convex surface) is greater than 10, and in a specific implementation, greater than 15. In an implementation, R1 is less than 0.5 mm, and the thickness between the two optical surfaces divided by the effective focal length is between 0.4 and 0.9 (0.4 < lens, lens thickness (distance between the two optical surfaces) divided by EFFL (EFFL is the effective focal length of the microlens) < 0.9).

[0035] AsFigure 3 As shown, each microlens 102 of the microlens array 104 images portions 302, 304, 306 of the fingerprint region 228 of the finger 226 and generates an image of that portion of the fingerprint region on different photoelectric sensor arrays 216 of the integrated circuit 108. In an embodiment, portions 302, 304, 306 of the fingerprint region 228 of the finger 226 (each lens imaging it onto the photoelectric sensor array 216) are centered directly above the photoelectric sensor array but are larger than the photoelectric sensor array; this is referred to as on-axis imaging. In an embodiment, each photoelectric sensor array is typically a photoelectric sensor array of at least 100×100. In an alternative embodiment, all lenses project images onto a single array of at least 400×400 photoelectric sensors, where each lens of the lens array projects its image onto a different region of the single photoelectric sensor array.

[0036] The fingerprint sensor module 100 is fabricated by a method 400 according to Figure 4 An infrared filter 210 is deposited 402 on the bottom side of a thin glass substrate that will become a spacer 208 having a thickness between (and including) 100 μm and 150 μm. Then a black light-absorbing coating or mask 212 is deposited 404 on the bottom side of the glass substrate 208, and if the infrared filter 210 is present, the light-absorbing coating 212 is deposited on the infrared filter 210. In some embodiments, a black mask 106 is also deposited on the top side of the glass substrate or spacer 208. Then the bottom black light-absorbing coating 212 and the black mask 106 (if used) are masked and etched to form openings 214, 215 and alignment marks (not shown), and these black coatings form baffles to improve image quality when forming lenses with small pitch and large image overlap regions.

[0037] The microlens array 104 as a wafer-level lens array is formed 406 by reflowing a reflowable optical material onto the top side of the glass substrate or spacer 208, and the reflowable optical material is shaped using a prefabricated wafer-sized mold. Alignment marks are used to align the mold and the optical material with the openings 214, 215 previously formed in the light-absorbing coating. Then the bottom side of the glass substrate or spacer 208 with the light-absorbing coating 212 is aligned and bonded 408 to the wafer of the integrated circuit 108. The assembled wafer with the microlenses 102, the glass substrate serving as the spacer 208, and the integrated circuit 108 can be tested, and defective circuits can be inked. Then, the assembled wafer is diced, typically by sawing, and the individual microlens arrays 104, the substrate or spacer 208, the black masks 106, 212, and the integrated circuit 108 components are bonded 410 to the flexible printed circuit 110 using a ball bond reflow technique.

[0038] The fingerprint sensor modules 100, 206 are used in a mobile phone 600( Figure 6 ). The mobile phone 600 includes an OLED display panel 220 that typically has touch sensing capabilities and can operate under the control of one or more processors 606. The processors 606 are coupled to receive raw images or extracted features from the fingerprint sensor 206. The one or more processors 606 operate under the control of firmware and an operating system 608 in a memory system 610 and are also coupled to one or more digital radio elements 612 configured to communicate bidirectionally with at least digital cellular towers. The processors 606 are also coupled to a global positioning system receiver and other sensors 614, such as an accelerator, a microphone, and speakers 616. And in many embodiments, the processors 606 are also coupled to a serial port 618 that is coupled to a universal serial bus (USB) interface 620. The mobile phone 600 is powered by a battery 222 through a power circuit and recharged by a charger 622.

[0039] The fingerprint sensor operates by a method 500( Figure 5 ). The method 500 includes illuminating 502 a fingerprint area 118 of a finger 226 using the OLED display panel 220; light from the fingerprint area 228 is focused by microlenses 102 onto a photoelectric sensor array 216 of an integrated circuit 108, and each microlens 102 focuses the light onto a plurality of photoelectric sensors of the photoelectric sensor array. Then the photoelectric sensor array is read 506 to form an overlapping electronic fingerprint image. Then, in some embodiments, the overlapping electronic fingerprint images are stitched 508 to form a single electronic fingerprint image. Then, features are extracted 512 from the single electronic fingerprint image or from the overlapping electronic fingerprint images, and then these features are compared 514 with features associated with one or more users in a feature library 630 in the memory system 610. The features in the feature library 630 include features associated with one or more fingers of one or more authorized users. A successful comparison verifies the identity of the user to whom the finger 226 belongs.

[0040] A lower-cost sensor with an outward angular field of view

[0041] Figures 2 to 3 The fingerprint sensor requires the photoelectric sensor array or the image sensor integrated circuit 108 to have a surface area that is almost as large as the fingerprint area 228. Since the integrated circuit processing cost is proportional to the integrated circuit area and the yield is inversely proportional to the integrated circuit area, cost reduction can be achieved if the surface area of the integrated circuit can be reduced. Figure 7 is a cross-sectional view of an optical fingerprint sensor 700. The optical fingerprint sensor 700 is in use with a reference having a ratio of Figure 2 and Figure 3While describing an integrated circuit with a smaller surface area required for on-axis imaging, off-axis micro-lens is used for outwards angular imaging to image the fingerprint area, as Figure 2 and Figure 3 the fingerprint sensors do.

[0042] In order to provide a wider imaging angle than the embodiment of Figures 2 to 3 Each micro-lens of the optical fingerprint sensor 700 has first concave micro-lens elements 702, 703 on the top surface of the transparent substrate 704. In some embodiments, the bottom surface 705 of the transparent substrate 704 has an infrared filter 706, and in other embodiments, the infrared filter 706 is omitted. On the bottom surface 705 of the transparent substrate 704 or the infrared filter 706 (if present) is a masking light-absorbing layer 708 with an opening 710 to allow imaging. Behind the opening 710 is a convex micro-lens element 712. The concave lens elements 702, 703 and the convex lens element 712 together function as a two-sided compound micro-lens. A partition 714 is provided to achieve a small space for the focal length of the compound micro-lens formed by the concave elements 702, 703 and the convex element 712, and the small focal length space is between the convex lens element 712 and the optoelectronic sensor array 716 of the integrated circuit 718. The small focal length space provided by the partition 714 allows the micro-lens to focus light onto the optoelectronic sensor array 716. In some but not all embodiments, additional light-absorbing masks 720 may be provided between and around the concave elements 702, 703 (but not on the concave elements 702, 703).

[0043] In a specific embodiment, the diameters of the concave lens elements 702, 703 and the convex lens element 712 are less than or equal to 1 millimeter (mm), the partition 714 achieves a space of 0.5 mm to 1.0 mm between the convex element 712 and the optoelectronic sensor array 716, and the thickness of the transparent substrate 704 is less than or equal to 0.2 mm, the thickness of the lens is 0.424 mm, and the effective focal length EFFL is 0.56 mm. In this embodiment, the radius R1 of the first concave surface divided by the radius R2 of the second convex surface is greater than 15, where R2 is less than 0.5 mm, and the lens thickness between the optical surfaces satisfies 0.4 < lens thickness (between the two optical surfaces) / EFFL < 0.9.

[0044] The micro-lenses in the central part of the array, such as the micro-lens incorporating the concave element 702, image the part 732 of the fingerprint area 738 centered above the lens, and the micro-lenses at the edge of the array, such as the micro-lens incorporating the concave element 703, image the part of the fingerprint area 738 offset in a direction away from the center of the array. These micro-lenses perform off-axis imaging of the fingerprint area. Compared with Figure 2 and Figure 3As in the embodiments, images from adjacent microlenses overlap and can be stitched to form an image of fingerprint area 738 of finger 740.

[0045] The microlenses are configured in an array of 1×1, 1×2, 2×2, 2×3, 3×3 or larger.

[0046] A microlens in the central portion of the array, such as microlens 802( Figure 8 ), images area 822 of fingerprint area 838 centered above microlens 802, and microlenses at the edges of the array, such as microlenses 804, 806, 808, 810, 812, image portions 824, 826, 828, 830, 832 of fingerprint area 838 offset from the center of the array.

[0047] Optical fingerprint sensor 700 is fabricated by method 900 according to Figure 9 . Infrared filter 706 is deposited 902 on the bottom side of thin glass substrate 704. Black light-absorbing coating or mask 708 is deposited 904, masked and etched on the bottom side of glass substrate 704, and if infrared filter 706 is present, masked light-absorbing coating 708 is deposited above infrared filter 706. In some embodiments, additional black light-absorbing coating or mask 720 is also deposited on the top side of glass substrate 704. The bottom black light-absorbing coating 708 and the additional light-absorbing coating 720 (if used) are masked and etched to form openings 710, 744 and alignment marks (not shown), and these light-absorbing coatings form obstacles that improve image quality by absorbing stray light and are particularly important when forming microlenses with small pitch and large image overlap regions.

[0048] The microlenses are formed 906, 907 as a wafer-level lens array by reflowing a reflowable optical material onto the top side of glass substrate 704, where the reflowable optical material is shaped using a prefabricated mold to form concave micro-elements 702, 703. The reflowable optical material is also applied to the bottom side of glass substrate 704 and shaped using another prefabricated mold to form convex microlens elements 712. Alignment marks are used to align the mold and the optical material with the previously formed openings 710, 744 in the light-absorbing coating. Then the bottom side of glass substrate 704 is aligned and bonded 908 to spacer 714, and then the assembled glass substrate 704 with the microlens elements and the spacer is aligned and bonded 910 to the wafer of integrated circuit 818. The assembled wafer with the microlens elements, the glass substrate, the spacer and the integrated circuit can be tested, and defective circuits are inked. Then, the assembled wafer is diced, typically by sawing, and individual integrated circuits are bonded 912 to flexible printed circuit 746 using ball bond reflow technology.

[0049] InFigure 10A In a particular embodiment illustrated in a side cross-sectional view, there is an optical path from a fingerprint through a microlens having a diameter of 0.05 mm, which microlens is formed in a conical cavity of a lens plate having a thickness of 1.088 mm and is configured to form an image of a field of view extending 102.6 degrees horizontally from the axis of the lens. In Figure 10B The microlens is illustrated in a top plan view in , where the inner circle represents the outer edge of the concave portion of the lower lens surface and the outer circle represents the outer edge of the integral partition forming the conical cavity within which the convex upper lens surface of the lens is formed. Figure 10C The lens is shown in a cross-section in , showing the lens 1006, the black mask 1002 that reduces stray light that may reach the photodiodes of the image sensor array, and the integral partition 1004.

[0050] In a different particular embodiment, the microlens is formed of six layers, as Figure 11A illustrated, where each layer is shown separately. A black absorptive coating 2 is applied to the first surface of a thin substrate glass wafer 3 having a thickness of 0.2 mm, and the coating is masked to remove a central portion of the coating having a diameter of 0.5 mm, thereby forming a hole through which light can reach a photoelectric sensor array after passing through each lens formed on the glass wafer 3. Then, a layer with a concave lens A structure 1 having a depth of approximately 0.144 mm is replicated on the first surface of the coated wafer, typically by deposition and molding of a reflowable lens material. A layer with a convex lens B structure 4 having a height of 0.171 mm is replicated on the second surface of the coated wafer, typically by deposition and molding. An adhesive layer 5 and a molded partition 6 having a height of 0.77 mm, a square shape of 1.96 mm, and coaxial with the axis. Then the lens and the partition are assembled onto an OLED panel 8 through which a fingertip with a fingerprint 9 can be seen.

[0051] Combination

[0052] The features described herein can be combined in various ways. Combinations of these features contemplated by the inventors include:

[0053] A multi-lens optical fingerprint reader designated as A and adapted to read fingerprints through a display includes: an image sensor integrated circuit having at least one photoelectric sensor array; a partition; and a plurality of microlenses arranged in a microlens array, each of the microlenses being configured to focus light reaching the microlens from a portion of a fingerprint area of a finger adjacent to the surface of the display to form an image on a plurality of photoelectric sensors associated with the microlens, the photoelectric sensors belonging to a photoelectric sensor array of at least one photoelectric sensor array in the image sensor integrated circuit. Each microlens includes a concave element on a first side of a transparent substrate and a convex element on a second side of the transparent substrate.

[0054] A fingerprint reader designated as AA, including a fingerprint reader designated as A, wherein for a microlens adjacent to the edge of the microlens array, the portion of the fingerprint area where light is focused by each microlens onto a plurality of photoelectric sensors is offset in a direction away from the center of the microlens array relative to the image formed on the plurality of photoelectric sensors associated with the microlens.

[0055] A fingerprint reader designated as AB, including a fingerprint reader designated as A or AA, further including at least one light-absorbing mask layer having an opening associated with each microlens of the microlens array.

[0056] A fingerprint reader designated as AC, including a fingerprint reader designated as A, AA or AB, wherein the microlens array includes at least a 1×2 microlens array.

[0057] A fingerprint reader designated as AD, including a fingerprint reader designated as AC, wherein the microlens array includes at least a 3×3 microlens array.

[0058] A fingerprint reader designated as AE, including a fingerprint reader designated as A, AA, AB, AC or AD, further including an infrared filter.

[0059] A method for verifying the identity of a user designated as B includes: illuminating the fingerprint area of the user's finger using an organic light-emitting diode (OLED) display panel; focusing the light from the fingerprint area through a microlens array onto at least one photoelectric sensor array of an integrated circuit, each microlens focusing a portion of the light from the fingerprint area onto a plurality of photoelectric sensors of the at least one photoelectric sensor array; reading the at least one photoelectric sensor array to form an overlapping electronic fingerprint image; extracting features by selecting a method of extracting features from the overlapping electronic fingerprint image and from a stitched image formed from the overlapping electronic fingerprint image; and comparing these features with the features of at least one user in a library of features associated with one or more fingers of one or more authorized users in a memory. Each microlens includes a concave element on a first side of a transparent substrate and a convex element on a second side of the transparent substrate.

[0060] A method for verifying identity designated as BA, including the method designated as B, wherein the microlenses of the microlens array and the photoelectric sensor array of the integrated circuit are configured such that the portion of the fingerprint area where light is focused by each microlens at the edge of the microlens array onto a plurality of photoelectric sensors is offset in a direction away from the center of the microlens array.

[0061] A method for verifying identity designated as BB, including the method designated as B or BA, further including at least one light-absorbing mask layer having an opening associated with each microlens of the microlens array.

[0062] A method of authenticating identity designated as BC, including methods designated as B, BB or BA, wherein the microlens array has a microlens array of at least 1×2.

[0063] A method of authenticating identity designated as BD, including the method designated as BC, wherein the microlens array has a microlens array of at least 3×3.

[0064] A method of manufacturing a fingerprint reader designated as C includes: forming an infrared filter on the bottom side of a thin glass substrate; depositing an absorptive coating on the infrared filter; masking and etching the absorptive coating to form an opening; forming an array of concave microlens elements on the thin glass substrate by reflowing a reflowable optical material onto the top side of the thin glass substrate and shaping the reflowable optical material using a first prefabricated wafer-sized mold; forming an array of convex microlens elements on the thin glass substrate by reflowing a reflowable optical material onto the bottom side of the thin glass substrate and shaping the reflowable optical material using a second prefabricated wafer-sized mold; aligning and bonding the thin glass substrate to a spacer to form a microlens panel; aligning and bonding the microlens panel to an integrated circuit wafer, each integrated circuit having at least one photoelectric sensor array; dicing the integrated circuit wafer; and bonding the integrated circuit to a flexible printed circuit.

[0065] A method designated as CA, including the method designated as C, wherein the microlens array and at least one photoelectric sensor array are configured such that the portion of the fingerprint area where light is focused from each microlens at the edge of the microlens array to a plurality of photoelectric sensors is offset in a direction away from the center of the microlens array.

[0066] Without departing from the scope of the present invention, changes can be made to the above methods and systems. Therefore, it should be noted that the content included in the above description or shown in the drawings should be understood as illustrative rather than restrictive. The following claims are intended to cover all general and specific features described herein, as well as all statements of the scope of the methods and systems of the present invention that can be said to be intermediate in language between the two.

Claims

1. A method for verifying the identity of a user, comprising: Illuminating a fingerprint area of a user's finger using an organic light emitting diode (OLED) display panel; Focusing light received from the fingerprint area through the OLED display panel onto at least one photoelectric sensor array of an integrated circuit by a microlens array, each microlens focusing a portion of the light from the fingerprint area onto a plurality of photoelectric sensors of the at least one photoelectric sensor array; Reading the at least one photoelectric sensor array to form an overlapping electronic fingerprint image; Extracting features from the overlapping electronic fingerprint image or from a stitched image formed from the overlapping electronic fingerprint image; And Comparing the features with at least one user's features in a library of features associated with one or more fingers of one or more authorized users in a memory; Wherein each microlens includes a concave element on a first side of a transparent substrate and a convex element on a second side of the transparent substrate; Wherein a ratio of a total optical path length of each microlens divided by an effective focal length of each microlens is between 0.5 and 2.

1.

2. The method according to claim 1, wherein the microlenses of the microlens array and the photoelectric sensor array of the integrated circuit are configured such that for at least a portion of the microlens array, a portion of the fingerprint area is offset in a direction away from the center of a first image, and light from the portion of the fingerprint area is focused onto the plurality of photoelectric sensors by each microlens at an edge of the microlens array, the first image being formed on the plurality of photoelectric sensors associated with the microlens.

3. The method according to claim 2, further comprising providing at least one light absorbing mask layer having an opening associated with each microlens of the microlens array.

4. The method according to claim 2, wherein the microlens array includes at least a 1×2 microlens array.

5. The method according to claim 4, wherein the microlens array includes at least a 3×3 microlens array.

6. The method according to claim 5, wherein the microlens includes a concave microlens and a convex microlens, and a ratio of a radius of curvature of a concave surface of the concave microlens to a radius of curvature of a convex surface of the convex microlens is greater than 10.

7. The method according to claim 6, wherein the radius of curvature of the convex surface of the convex microlens is less than 0.5 mm, and a ratio of a lens thickness measured between the concave surface of the concave microlens and the convex surface of the convex microlens divided by the effective focal length of the microlens is between 0.4 and 0.

9.

8. The method according to claim 7, wherein a ratio of the radius of curvature of the convex surface of the convex microlens divided by the effective focal length of each microlens is between 0.44 and 0.

61.

9. The method according to claim 5, wherein each microlens has a field of view of at least 102.6 degrees.

10. The method according to claim 5, wherein the features are extracted from a stitched image formed from the overlapping electronic fingerprint image.

11. The method according to claim 5, wherein the at least one optoelectronic sensor array includes different optoelectronic sensor arrays associated with each microlens.

Images