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

Abstract

A fingerprint sensor and a system incorporating the fingerprint sensor are provided. The image sensor for imaging a fingerprint has a plurality of photodiode groups, each photodiode group having a field of view determined by the position of the optical properties of the microlens, the microlens, and the openings of the upper mask layer and the openings of the lower mask layer, each field of view passing through the microlens. Many of the photodiode groups have fields of view that fan out from a central straight field of view. The diameter of the openings of the upper mask layer away from the group having the central straight field of view is greater than the diameter of the openings of the photodiode group having the central straight field of view. A method of matching the illumination of the photodiode group having the central straight field of view with the illumination of the photodiode group having the fan out field of view includes sizing the openings in the upper mask layer of the photodiode group having the fan out field of view to be greater than the openings in the upper mask layer associated with the photodiode group having the central straight field of view.

Description

TECHNICAL FIELD

[0001] The present invention relates to the field of sensors, and in particular to a fingerprint sensor and a system incorporating a fingerprint sensor. BACKGROUND

[0002] Many modern phone operating systems, including Apple iOS and Android, are configurable to use a biometric, such as a fingerprint, as an alternative to a user input unlock code to verify user identity. Existing optical sensors for reading a fingerprint use an electronic camera equipped with a single lens and an image sensor with a single array of photodiodes to image the fingerprint surface of a finger through an OLED phone display. In order to image a reasonable area of the finger, the lens and the array of photodiodes are large, and a considerable space is required between the lens and the array of photodiodes— which is problematic in the limited space available in a phone.

[0003] As phone processing power and display size increase, phone power requirements increase, yet customers demand long battery life. These two pressures force phone designers to adopt larger and larger batteries. Increasing battery size without increasing phone size requires the battery to extend to the entire back of the phone— encroaching on the space previously occupied by the single-lens fingerprint sensor optics.

[0004] The cost of manufacturing a wafer of integrated circuits, including image sensor integrated circuits, is relatively constant for a given process, while there are more circuits per wafer for small circuits than for large circuits. Large circuits also have a higher probability of manufacturing defects than small circuits. These two effects make it more expensive to manufacture large circuits than small circuits on the same process. SUMMARY

[0005] An image sensor for imaging a fingerprint has a plurality of photodiode groups, each field of view of each photodiode group is determined by the location of the optical properties of a microlens, the microlens, and an opening of an upper mask layer and an opening of a lower mask layer, each field of view passing through the microlens. Many of the photodiode groups have a field of view that flares outward from a center direct field of view (or center vertical field of view or center vertical field). The diameter of the opening of the upper mask layer away from the photodiode group with the center direct field of view is larger than the diameter of the opening of the photodiode group with the center direct field of view.

[0006] A method of matching illumination of a photodiode group with a center direct field of view with illumination of a photodiode group with a field of view that flares outward includes sizing the opening in the upper mask layer of the photodiode group with the field of view that flares outward to be larger than the opening in the upper mask layer associated with the photodiode group with the center direct field of view.

[0007] A system includes a fingerprint sensor comprising: a plurality of photodiode groups, a field of view of each photodiode group being determined by an opening of an upper mask layer, an opening of a lower mask layer, a pinhole in a metal layer, and a position of the photodiode group and an optical property of the microlens, each field of view passing through the microlens; wherein each microlens associated with the plurality of photodiode groups has a field of view that flares outward from a central straight field of view; wherein a first photodiode group of the plurality of photodiode groups associated with each microlens has a non-vertical field of view at a first angle relative to a vertical field of view, a second photodiode group of the plurality of photodiode groups associated with each microlens has a non-vertical field of view at a second angle relative to the vertical field of view, the second angle being equal to a negative of the first angle. The system further includes a processor coupled to read the photodiode groups of the fingerprint sensor; a memory coupled to the processor, the memory having recorded therein a photodiode to fingerprint image mapping, and a feature library; wherein the processor is configured to illuminate a fingerprint region of a finger, obtain readings from the photodiode groups of the fingerprint sensor, place the readings in a fingerprint image according to the photodiode to fingerprint image mapping, extract features from the fingerprint image, and compare the extracted features to features in the feature library to identify a user.

[0008] In one aspect, a fingerprint sensor includes a plurality of microlenses; for each microlens of the plurality of microlenses, a plurality of photodiode groups associated with the microlens, each photodiode group including at least one photodiode and having a field of view determined by an opening of an upper mask layer, an opening of a lower mask layer, and a position of the photodiode group and the microlens and an optical property of the microlens, each field of view passing through the microlens, wherein the photodiode groups have non-vertical fields of view at a plurality of angles different from a vertical field of view, wherein a first photodiode group of the plurality of photodiode groups has a non-vertical field of view at a first angle relative to the vertical field of view, a second photodiode group of the plurality of photodiode groups has a non-vertical field of view at a second angle relative to the vertical field of view, the second angle being equal to a negative of the first angle.

[0009] In some embodiments, a first plurality of microlenses is associated with a first photodiode group, a field of view of the first photodiode group overlaps a field of view of a second photodiode group associated with a second plurality of microlenses, the first plurality of microlenses is different from the second plurality of microlenses.

[0010] In some embodiments, the non-vertical field of view includes a field of view that differs from the vertical field of view by at least 10 degrees.

[0011] In some embodiments, the non-vertical field of view includes a field of view that differs from the vertical field of view by at least 12 degrees.

[0012] In some embodiments, the non-vertical field of view includes a field of view that differs from the vertical field of view by at least 17 degrees.

[0013] In some embodiments, the non-vertical field of view includes a field of view that differs from the vertical field of view by less than or equal to 20 degrees.

[0014] In some embodiments, the fingerprint sensor further includes a plurality of photodiode groups, the plurality of photodiode groups having a vertical field of view through the microlenses of the plurality of microlenses.

[0015] In some embodiments, a system including the above-described fingerprint sensor, a memory, and a processor, wherein the memory includes code configured to obtain readings of the first and second photodiode groups associated with the first and second plurality of microlenses and use the readings and a photodiode to fingerprint image mapping to construct a fingerprint image.

[0016] In some embodiments, each photodiode group includes a single photodiode.

[0017] In some embodiments, each photodiode group includes a plurality of photodiodes.

[0018] In some embodiments, the plurality of microlenses is associated with an additional photodiode group having a vertical field of view.

[0019] In some embodiments, the additional photodiode group having a vertical field of view is associated with a light filter.

[0020] In some embodiments, for each photodiode group of the plurality of photodiode groups associated with each microlens of the plurality of microlenses, the field of view is further defined by a pinhole in the metal layer.

[0021] In another aspect, a system incorporating a fingerprint sensor, the fingerprint sensor including a plurality of photodiode groups, each photodiode group having a field of view determined by a microlens, an opening of an upper mask layer, an opening of a lower mask layer, a pinhole in a metal layer, and a location of the photodiode group, and optical properties of the microlens, each field of view being through the microlens; wherein each microlens associated with the plurality of photodiode groups has a field of view that flares outward from a central straight field of view; wherein a first photodiode group of the plurality of photodiode groups associated with each microlens has a non-vertical field of view at a first angle relative to a vertical field of view, a second photodiode group of the plurality of photodiode groups associated with each microlens has a non-vertical field of view at a second angle relative to the vertical field of view, the second angle being equal to a negative of the first angle.

[0022] In some embodiments, the system further comprises a processor coupled to read the photodiode set of the fingerprint sensor; a memory coupled to the processor, the memory having recorded therein a photodiode to fingerprint image mapping, and a feature library; wherein the processor is configured to illuminate a fingerprint region of a finger, obtain readings from the photodiode set of the fingerprint sensor, place the readings in a fingerprint image according to the fingerprint image mapping, extract features from the fingerprint image, and compare the extracted features to features in the feature library to identify the user.

[0023] In some embodiments, the system further comprises an anti-spoofing routine in the memory.

[0024] In some embodiments, the system is embedded in a cellular telephone.

[0025] In some embodiments, the system is embedded in a safe or access control lock.

[0026] In some embodiments, the anti-spoofing routine verifies a color of the fingerprint region of the finger.

[0027] In some embodiments, the anti-spoofing routine identifies sweat pore openings in the fingerprint region of the finger. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 Cross-sectional schematic of a finger, OLED display, optical fingerprint sensor module, and flexible circuit board, the optical fingerprint sensor module having a microlens array, a mask with openings or pinholes, a spacer, and an image sensor.

[0029] Figure 2 Cross-sectional schematic of a fingerprint sensor module of Figure 1 , illustrating multiple photodiode sets for a field of view ranging from a central direct angle to a maximum outward opening angle.

[0030] Figure 3 Top view of four adjacent microlenses, illustrating four photodiode sets associated with each microlens in a fingerprint sensor and associated mask layer openings and pinholes.

[0031] Figure 3A Top view of an embodiment similar to that of Figure 3 , but with an additional central narrow field of view photodiode set and associated openings and pinholes provided for anti-spoofing purposes.

[0032] Figure 3B Top view of an embodiment having two pairs of openings associated with each microlens in the upper and lower mask layers instead of four pairs of openings.

[0033] Figure 4 FIGURE illustrates a view of a left and right perspective photodiode group.

[0034] Figure 5 For an enlarged view illustrating the opening of the lower mask layer and the pinholes in the metal layer for each opening of the upper layer, each pinhole in the metal layer and the opening of the lower mask layer are associated with a photodiode group.

[0035] Figure 6 For a flowchart illustrating the operation of the fingerprint sensor.

[0036] Figure 7 For a block diagram of a cellular telephone device that can use an optical fingerprint sensor. DETAILED DESCRIPTION

[0037] To provide a fingerprint sensor that is thin enough to fit between an organic light emitting diode (OLED) screen and a phone battery, we use a sensor similar to the compound insect eye that has many microlenses, each of which focuses light on one or a small group of associated photodiodes. Each microlens is provided with multiple collimators, each of which provides light for a separate group of one or more photodiodes. In addition, to help minimize the area of the fingerprint sensor, we flare the collimators' field of view; by doing so, the sensor can be smaller than the area of the fingerprint it is configured to take, while providing high resolution from the overlapping fields of view in the central area of the fingerprint.

[0038] In a typical fingerprint, the ridges have a lower reflectivity than the valleys between the ridges. The fingerprint sensor takes pictures of these ridges and valleys, so the processor can compare the patterns in the ridges and valleys to a database of one or more master patterns.

[0039] In example 100( Figure 1 ), in which the height of the phone components is greatly exaggerated, the fingerprint area 104 of the finger 102 is positioned above the OLED screen 106. Below the OLED screen 106 is the fingerprint sensor 108, which is ball-bonded 110 to a flexible circuit board 112. The circuit board 112 can be coupled to other circuit boards 116 of the phone through a connector 114. Below the circuit board 112 is the battery 118 and the backplane 120 of the phone.

[0040] The fingerprint sensor 108( Figure 1 and Figure 2having a microlens array in which each microlens 124 is aligned with two, four or more openings 125 in an upper mask layer 126 and an opening pair in a lower mask layer 128, the openings in masks embedded in a transparent spacer 129. Typically, the upper mask layer 126 and the lower mask layer 128 are black masks of light absorbing material. The microlens 124, the openings 125 in the upper mask layer 126 and the lower mask layer 128 are aligned with a photodiode group 152, 156 formed in a semiconductor 130, each photodiode group having one or more photodiodes.

[0041] The openings 125 in the upper mask layer 126 and the openings 144 in the lower mask layer 128 are associated with each microlens 124, form a view group 166 and are aligned so that a first photodiode group 156 associated with a microlens 124 has a left angled field of view 154 and a second photodiode group 152 has a right angled field of view 162. Each photodiode group has one or more photodiodes. For the purposes of this document, an angled field of view that does not directly sight the nearest point of the fingerprint area 104, such as the left field of view 154 and the right field of view 162, is the outward angled field of view for that microlens. Each field of view is determined by the alignment of the photodiode groups 152, 156, the openings of both upper and lower mask layers and the position of the microlens and the optical properties of the microlens and passes through the microlens 124 of the microlens array.

[0042] In embodiments, a metal layer with pinholes is disposed between the lower mask layer 128 and the photodiode groups, the pinholes in the mask layer aligned with the openings 125 in the upper mask layer and the openings 144 in the lower mask layer.

[0043] In embodiments, in each view group 166, the left angled field of view 154 has a first angle to the vertical field of view and the right angled field of view 162 has a second angle, where the first angle is the negative of the second angle. Both the left angled field of view 154 and the right angled field of view 162 are non-vertical.

[0044] Figure 3 A portion of a microlens, opening and pinhole array 300 is illustrated in cross section. Four adjacent microlenses 302 are illustrated, each microlens 302 having four opening pairs 304, 306, 308, 310 (the larger opening 312 in each pair is in the upper mask layer and the smaller opening is in the lower mask layer) and each pair is associated with a photodiode group having one or more photodiodes (not shown in this cross section). Figure 3

[0045] A portion of an alternative microlens, opening and pinhole array 350 (illustrated in plan view) Figure 3A ) is similar to Figure 3 ​The micro-lens, open and pin-hole array 300 in FIG. 3B, but with an optional, additional central narrow field-of-view photodiode group and associated small diameter opening 352, 354 disposed under some or all of the micro-lenses, the additional photodiode group having a different color sensitivity than the photodiode groups associated with the pairs of openings 304, 306, 308, 310, and used for fingerprint spoofing countermeasures, such as verifying finger color under visible and infrared light.

[0046] Another alternative micro-lens, open and pin-hole array 370 (partially illustrated in plan view) has two pairs of openings in the upper mask layer 372 and lower mask layer 374, instead of the four pairs of openings illustrated in FIG. 3A, each pair of openings associated with a photodiode group. In this embodiment, some of the photodiode groups, such as the photodiode groups associated with the pair of openings 376 and where the field-of-view overlaps the field-of-views of other photodiode groups, have a filter to provide a different color response than the other photodiode groups 378, and used for fingerprint spoofing countermeasures, such as verifying finger color under visible and infrared light. Figure 3B Figure 3 Figure 3B

[0047] In a practical embodiment, there are thousands of micro-lenses 302, pairs of openings 304, 306, 308, 310 and photodiode groups 152, 156 in the array to provide sufficient resolution to identify the fingerprint of a particular individual. In an embodiment, the angle of the field-of-view of the central ray of a photodiode group through an aligned opening to the vertical, straight field-of-view of the fingerprint area 104 can be in the range of ten to twelve to seventeen to less than or equal to twenty degrees. This allows the fingerprint sensor 108 to be significantly smaller than the entire scanned fingerprint area 104. Each multi-opening collimator can have a fairly narrow field-of-view, in some embodiments only three degrees or less. In an embodiment, the micro-lens pitch can be in the range of twenty to twenty-five microns.

[0048] The views of the fingerprint area 104 from the aligned openings associated with the left-view photodiode group 156 and right-view photodiode group 152 on the left side 404 and right side 406 of the micro-lens array 402 (FIG. 4A) are illustrated as left view 408 and right view 410; these view areas overlap in the overlap area 412. The left view 408 and right view 410 are combined and imaged together to form a fingerprint image for identifying a user. Figure 4

[0049] ​​​​The overlap region 412 can be used to provide a higher resolution fingerprint image of the portion of the fingerprint region 104 located within the overlap region 412. In an optional embodiment, some of the photodiode groups that would otherwise overlap are equipped with color filters 414 having one, three, or more color passband characteristics to allow full-color or hyperspectral color verification of the fingerprint region 104 to match the infrared, color, or hyperspectral color characteristics of a human fingerprint, exceeding the color resolution that can be achieved by changing the color provided to the fingerprint region 104 by the OLED screen 106. In a specific embodiment, the color filters 414 include an infrared pass filter with two wavelengths, a visible light blocking filter, a red pass filter, a green pass filter, and a blue pass filter, which allows for determination of whether the fingerprint region 104 displays red and infrared spectral characteristics associated with oxygenated hemoglobin, as well as full-color verification; by observing the oxygenation of hemoglobin for a few seconds, the presence of a pulse in the finger 102 can be verified. While a monochrome fingerprint image is sufficient to identify the fingerprint pattern, this red and infrared, full-color, or hyperspectral color verification can be used as an anti-spoofing method in an anti-spoofing routine by identifying some fake fingerprint regions associated with a replica or fake finger. In addition to identifying the color of fingerprint region 104, in some embodiments, sufficient color resolution is provided to image the pattern of blood vessels 103 within finger 102. In other embodiments, sufficient resolution is provided to identify some sweat gland pores in fingerprint region 104 and map these sweat gland pores relative to the acquired fingerprint image; again, these sweat gland pores are often absent in fake fingers, and this mapping of sweat gland pores to the fingerprint image is used as an anti-spoofing method in an anti-spoofing routine.

[0050] In an embodiment, within each viewing group 166 and below the opening 144 in the lower mask layer 128 is a metal layer 502 ( Figure 5 ). In the metal layer 502 are pinholes 504, 506. These pinholes 504, 506 are aligned with the opening 144 in the lower mask layer 128 and help to reduce the field of view width of each photodiode group. It should be noted that in Figure 1 、 2 3, but are omitted for clarity. In a particular embodiment, the pinholes 504, 506 have a diameter of 4 microns, the opening 144 in the lower mask layer 128 has a diameter of 14 to 17 microns, and the opening 125 in the upper mask layer 126 has a diameter of 15 to 18 microns.

[0051] In an optional embodiment, additional, optional photodiode groups 520 provided for anti-spoofing purposes and aimed directly at the fingerprint region 104 have optional pinholes 522 having a diameter of approximately 2 microns in the metal layer 502 and view the fingerprint region directly with a narrow field of view 528 through vertically aligned small openings 524 in the lower mask layer 128; these optional, additional photodiode groups 520 can be associated with optional color filters 526 and can view the fingerprint region 104 through dedicated holes in the upper mask layer 126, or can share openings 125 in the upper mask layer 126 with another photodiode group, such as photodiode groups 152 (shown) or 156.

[0052] Fingerprint sensor 108 for cellular phone 600 ( Figure 7 ); a smart cell phone 600 or other electronic device (such as a tablet, quick-access gun safe, entry control system, or tablet) incorporates an OLED screen 106, typically with touch sensing capabilities, operating under the control of one or more processors 606, which are coupled to receive the raw image or extracted features from the fingerprint sensor 108. 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 radios 612 configured for two-way communication with at least a digital cellular tower. The processor 606 is also coupled to a global positioning system receiver and other sensors 614 (such as an accelerometer), a microphone, and a speaker 616. In many embodiments, the processor 606 is also coupled to a serial port 618, which is coupled to a universal serial bus (USB) interface 620. The cell phone 600 is powered by the battery 118 through a power circuit and recharged by a charger 622.

[0053] In an embodiment where both the left view 408 and right view 410 angled photodiodes or pixels of the fingerprint sensor are used in the overlap region 412 to provide a high resolution fingerprint image, the memory system 610 contains a spatial, cell phone 600 model and OLED screen 106 thickness specific photodiode group to fingerprint image mapping 609 for a temporary fingerprint image 611, the mapping 609 including a mapping of the right view photodiode group 152 and the left view photodiode group 156 to pixels of the temporary fingerprint image.

[0054] The fingerprint sensor is controlled by a processor 606 ( Figure 7 ) method 550( Figure 6 ) operation, the method 550 includes illuminating 552 the fingerprint area 104 of the finger 102 using the OLED screen 106 ( Figure 2); light from the fingerprint area 104 is focused 554 through the microlens 124 onto the associated photodiode set 152, 156 of the fingerprint sensor. The photodiode set 132 is then read 556 and remapped 558 and recorded to form an electronic fingerprint image in a temporary fingerprint image 611 as remapped by the photodiode set to fingerprint image mapping 609. Features are then extracted 562 from the electronic fingerprint image or overlapping electronic fingerprint images; these features are then compared 564 to features associated with one or more users in a feature library 630 of features, the feature library 630 including features associated with one or more fingers of one or more authorized users in the memory system 610. A successful comparison verifies the identity of the user to whom the finger 102 belongs, while an unsuccessful comparison can deny access.

[0055] To verify that the finger 102 is a real finger, additional anti-spoofing methods 566 are performed by an anti-spoofing routine that can include one or more of identifying sweat pore locations of the finger 102 and comparing to known sweat pore locations in the feature library 630, color or hyper-color imaging of the finger 102 to verify that the finger 102 has colors similar to human fingers, infrared or optical imaging of blood vessels in the finger 102, or extracting oxygen saturation from dual-color imaging of the finger 102 to detect a pulse that is not normally present in a fake finger.

[0056] In optional embodiments such as a gun safe or building access control lock, the illumination can be provided by a device other than an OLED panel, such as a light-emitting diode or a lamp.

[0057] Feature combinations

[0058] The concepts and features described herein can be combined in various ways, some of which are contemplated by the inventors, including the following:

[0059] A fingerprint sensor designated A, comprising a plurality of microlenses; for each microlens, a plurality of photodiode sets having one or more photodiodes associated with the microlens, each photodiode set having a field of view determined by the openings of the upper mask layer, the openings of the lower mask layer, the locations of the photodiode sets and the microlenses, and the optical properties of the microlenses, each field of view passing through the microlens. The photodiode sets have non-vertical fields of view at a plurality of angles other than a vertical field of view, a first photodiode set of the plurality of photodiode sets having a non-vertical field of view at a first angle relative to the vertical field of view, a second photodiode set of the plurality of photodiode sets having a non-vertical field of view at a second angle relative to the vertical field of view, the second angle equaling the negative of the first angle.

[0060] A fingerprint sensor designated AA comprising a fingerprint sensor designated A, wherein a first plurality of microlenses is associated with a first photodiode group, a field of view of the first photodiode group overlapping a field of view of a second photodiode group associated with a second plurality of microlenses, the first plurality of microlenses being different than the second plurality of microlenses.

[0061] A fingerprint sensor designated AB comprising a fingerprint sensor designated A or AA, wherein a non-vertical field of view comprises a field of view that differs from a vertical field of view by at least 10 degrees.

[0062] A fingerprint sensor designated AC comprising a fingerprint sensor designated AB, wherein a non-vertical field of view comprises a field of view that differs from a vertical field of view by at least 12 degrees.

[0063] A fingerprint sensor designated AD comprising a fingerprint sensor designated AC, wherein a non-vertical field of view comprises a field of view that differs from a vertical field of view by at least 17 degrees.

[0064] A fingerprint sensor designated AE comprising a fingerprint sensor designated A, AA, AB, AC, or AD, wherein a non-vertical field of view comprises a field of view that differs from a vertical field of view by less than or equal to 20 degrees.

[0065] A fingerprint sensor designated AF comprising a fingerprint sensor designated A, AA, AB, AC, AD, or AE, further comprising a plurality of photodiode groups having a vertical field of view that passes through a microlens of the plurality of microlenses.

[0066] A system designated B comprising a fingerprint sensor designated A, AA, AB, AC, AD, AE, or AF, a memory, and a processor, wherein the memory comprises code configured to obtain readings of first and second photodiode groups associated with first and second pluralities of microlenses and use the readings and a photodiode-to-fingerprint image mapping to construct a fingerprint image.

[0067] A fingerprint sensor designated AG comprising a fingerprint sensor designated A, AA, AB, AC, AD, AE, or AF, wherein each photodiode group comprises a single photodiode.

[0068] A fingerprint sensor designated AH comprising a fingerprint sensor designated A, AA, AB, AC, AD, AE, or AF, wherein each photodiode group comprises a plurality of photodiodes.

[0069] A fingerprint sensor designated AJ comprising a fingerprint sensor designated AF, wherein an additional photodiode group having a vertical field of view is associated with a filter.

[0070] A fingerprint sensor designated AK, including a fingerprint sensor designated A, AA, AB, AC, AD, AE, AF, AG, AH, or AJ, wherein for each photodiode group of a plurality of photodiode groups associated with each microlens of a plurality of microlenses, the field of view is further defined by a pinhole in a metal layer.

[0071] A system incorporating a fingerprint sensor designated C, the fingerprint sensor including: a plurality of photodiode groups, each photodiode group having a field of view determined by a microlens, an opening of an upper mask layer, an opening of a lower mask layer, a pinhole in a metal layer, and a location of the photodiode group and optical properties of the microlens, each field of view passing through the microlens; wherein each microlens associated with the plurality of photodiode groups has a field of view that flares outward from a central straight field of view; wherein a first photodiode group of the plurality of photodiode groups associated with each microlens has a non-vertical field of view at a first angle relative to a vertical field of view, a second photodiode group of the plurality of photodiode groups associated with each microlens has a non-vertical field of view at a second angle relative to the vertical field of view, the second angle equaling a negative of the first angle.

[0072] A system designated CA, including the system designated C, further including a processor coupled to read photodiode groups of the fingerprint sensor; a memory coupled to the processor, the memory having recorded therein a photodiode to fingerprint image mapping, and a library of features; wherein the processor is configured to illuminate a fingerprint region of a finger, obtain readings from the photodiode groups of the fingerprint sensor, and place the readings in a fingerprint image according to the photodiode to fingerprint image mapping, extract features from the fingerprint image, and compare the extracted features to features in the library of features to identify a user.

[0073] A system designated CA, including the system designated C, further including an anti-spoofing routine in the memory.

[0074] A system designated CB, including the system designated C or CA, embedded in a cellular telephone.

[0075] A system designated CC, including the system designated C or CA, embedded in a safe or access control lock.

[0076] A system designated CD, including the system designated C, CA, CB, or CC, wherein the anti-spoofing routine verifies a color of a fingerprint region of a finger.

[0077] A system designated CE, including the system designated C, CA, CB, CC, or CD, wherein the anti-spoofing routine identifies a sweat pore in a fingerprint region of a finger.

[0078] Changes can be made to the above methods and systems without departing from the scope of the present application. Accordingly, it is intended that all requirements disclosed in connection with the above description be interpreted in the broadest reasonable manner rather than in an limited manner. The following claims are intended to cover all generic and specific features of the methods and systems described herein, as well as all statements of the scope of the present application method and system which, as a matter of language, might be said to fall therebetween.

Claims

1. A fingerprint sensor comprising: multiple microlenses; for each microlens in the plurality of microlenses, a plurality of photodiode groups associated with the microlens, each photodiode group comprising at least one photodiode and having a field of view determined by optical characteristics of the microlens and an opening in an upper mask layer, an opening in a lower mask layer, and a position of the photodiode group and the microlens, each field of view passing through the microlens, wherein the plurality of photodiode groups are angled photodiode groups having non-vertical fields of view at a plurality of angles different from a vertical field of view, wherein a first group of the plurality of angled photodiode groups has a non-vertical field of view at a first angle relative to the vertical field of view, and a second group of the plurality of angled photodiode groups has a non-vertical field of view at a second angle relative to the vertical field of view, the second angle being equal to a negative value of the first angle; wherein the upper mask layer and the lower mask layer are embedded in a transparent backing plate, and wherein a metal layer having angled pinholes is disposed between the lower mask layer and the photodiode group, the angled pinholes in the metal layer being aligned with the openings in the upper mask layer, the openings in the lower mask layer, and the angled photodiode group selected from the first angled photodiode group and the second angled photodiode group; as well as Also included are a plurality of vertical photodiode groups having a vertical field of view through the microlenses of the plurality of microlenses; The photodiode group has a vertical field of view associated with a vertical pinhole in the metal layer, the vertical pinhole being separated from the angled pinhole.

2. The fingerprint sensor of claim 1, wherein the vertical pinhole is smaller than the angled pinhole.

3. The fingerprint sensor of claim 2, wherein the vertical pinhole is associated with a vertical filter that is different from any filter associated with the angled pinhole.

4. The fingerprint sensor according to claim 3, wherein a first plurality of microlenses are associated with a first plurality of photodiode groups, a field of view of the first plurality of photodiode groups overlaps a field of view of a second plurality of photodiode groups associated with a second plurality of microlenses, and the first plurality of microlenses are different from the second plurality of microlenses. 5 . The fingerprint sensor of claim 4 , wherein the non-vertical field of view comprises a field of view that differs from a vertical field of view by at least 10 degrees. 6 . The fingerprint sensor of claim 5 , wherein the non-vertical field of view comprises a field of view that differs from the vertical field of view by at least 12 degrees.

7. The fingerprint sensor of claim 6, wherein the non-vertical field of view comprises a field of view that differs from a vertical field of view by at least 17 degrees.

8. The fingerprint sensor of claim 7, wherein the non-vertical field of view comprises a field of view that differs from the vertical field of view by less than or equal to 20 degrees.

9. The fingerprint sensor of claim 4, wherein each photodiode group comprises a single photodiode.

10. The fingerprint sensor of claim 4, wherein each photodiode group comprises a plurality of photodiodes.

11. The fingerprint sensor of claim 4, wherein for each of the plurality of photodiode groups associated with each of the plurality of microlenses, the field of view is further defined by the pinhole in the metal layer.

12. A system comprising the fingerprint sensor of claim 1, a memory, and a processor, wherein the memory includes code configured to obtain readings of a first plurality of photodiode groups associated with a first plurality of microlenses and a second plurality of photodiode groups associated with a second plurality of microlenses and to construct a fingerprint image using the readings and a photodiode-to-fingerprint image mapping, and The plurality of microlenses include the first plurality of microlenses and the second plurality of microlenses, and the plurality of photodiode groups include the first plurality of photodiode groups and the second plurality of photodiode groups.

13. A fingerprint sensor comprising: multiple microlenses; for each microlens in the plurality of microlenses, a plurality of angled photodiode groups associated with the microlens, each angled photodiode group comprising at least one photodiode and having a field of view determined by optical characteristics of the microlens and an opening in an upper mask layer, an opening in a lower mask layer, and a position of the angled photodiode group and the microlens, each field of view passing through the microlens, wherein the angled photodiode groups have non-vertical fields of view at a plurality of angles different from a vertical field of view, wherein a first angled photodiode group in the plurality of photodiode groups has a non-vertical field of view at a first angle relative to the vertical field of view, and a second angled photodiode group in the plurality of angled photodiode groups has a second angle relative to the vertical field of view, the second angle being equal to a negative value of the first angle; wherein the upper mask layer and the lower mask layer are embedded in a transparent backing plate, and wherein a metal layer having angled pinholes is disposed between the lower mask layer and the angled photodiode group, the angled pinholes in the metal layer being aligned with the openings of the upper mask layer, the openings of the lower mask layer, and the angled photodiode group; wherein the plurality of microlenses are associated with a vertical photodiode group having a vertical field of view; wherein the group of photodiodes having the vertical field of view is associated with a filter and is associated with a vertical pinhole in the metal layer that is smaller than the angled pinhole, the filter causing the group of photodiodes having the vertical field of view to have a different color sensitivity than the plurality of angled photodiode groups associated with the microlenses.

14. A system comprising the fingerprint sensor according to claim 13, further comprising: a processor coupled to read the set of photodiodes of the fingerprint sensor; A memory coupled to the processor, wherein the memory records a mapping from a photodiode to a fingerprint image and a feature library; in The processor is configured to illuminate a fingerprint area of ​​a finger, obtain readings from the set of photodiodes of the fingerprint sensor, place the readings in a fingerprint image according to the fingerprint image map, extract features from the fingerprint image, and compare the extracted features with features in the feature library to identify the user.

15. The system of claim 14, further comprising an anti-spoofing routine in the memory.

16. The system of claim 15, embedded in a cellular phone.

17. The system of claim 15, embedded in a safe or an access control lock.

18. The system of claim 15, wherein the anti-spoofing routine verifies a color of the fingerprint region of the finger.

19. The system of claim 15, wherein the anti-spoofing routine identifies sweat gland pores in the fingerprint area of ​​the finger.

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