WO2022046034A1

WO2022046034A1 - Distributed support structure for a large-area optical under-display fingerprint sensor

Info

Publication number: WO2022046034A1
Application number: PCT/US2020/047787
Authority: WO
Inventors: Firas Sammoura; Matteo CARRARA
Original assignee: Google Llc
Priority date: 2020-08-25
Filing date: 2020-08-25
Publication date: 2022-03-03

Abstract

This disclosure describes methods and techniques for a distributed support structure for a large-area optical under-display fingerprint sensor. Using these techniques, a large-area optical under-display fingerprint sensor (UDFPS) can be implemented in or under a display of an electronic device. The distributed support structure helps maintain a uniform gap between the UDFPS and a display on which a user provides a fingerprint, which can improve performance, reliability, and accuracy of the UDFPS and improve the customer's experience. Further, the techniques may also allow a manufacturer to use adhesives or other components that are easier to repair and rework, which can reduce damage to the display or the UDFPS and thereby decrease manufacturing and repair costs.

Description

DISTRIBUTED SUPPORT STRUCTURE FOR A LARGE-AREA

OPTICAE UNDER-DISPEAY FINGERPRINT SENSOR

BACKGROUND

[oooi] To enable a fingerprint sensor in an electronic device without taking up valuable space on a display side of the device, the fingerprint sensors can be located in or under the display. For example, the electronic device can be manufactured with an optical under-display fingerprint sensor (UDFPS) under an organic light-emitting diode (OLED) display. There are several options for integrating a typical optical UDFPS with the display. The optical UDFPS can be attached directly to the display by lamination and with a liquid optically-clear adhesive layer between the display and the optical UDFPS. In other cases, the optical UDFPS can be attached to a physical structure of the electronic device, such as a mid-frame support or a grounding structure, along the perimeter of the optical UDFPS, sometimes referred to as frame attachment.

[0002] Some users do not like having to enter their fingerprint at a specific location because it is often inconvenient. In response, manufacturers sometimes use several fingerprint sensors to provide additional locations that can accept a fingerprint. This technique can increase costs for both materials and manufacturing, and multiple sensors can also increase repair and rework costs. Consequently, many manufacturers may prefer to use a large-area optical UDFPS so that the fingerprint can be scanned from anywhere on the display. But a large-area optical UDFPS must be thin to maintain the desired device thickness without infringing on the space available for the battery. Additionally, in many cases, the large area and the relative thinness may indicate that typical integration methods may be inadequate.

[0003] For example, attaching a large-area optical UDFPS using a frame attachment technique can lead to bending or warping of the large-area optical UDFPS (because of the larger area with only perimeter attachment), which may, in turn, cause a non-uniform gap between display and UDFPS. Similarly, during operation of the large-area optical UDFPS, finger pressure can cause display deformation, particularly toward a center of the display, distal from the attached edge of the display. Further, when the large-area optical UDFPS includes a micro-lens array as a focusing mechanism, the large-area optical UDFPS cannot be directly attached to the display because the micro-lens array has better performance when there is a fixed, uniform air-gap between the micro-lens array and the display. These issues may cause performance degradation by, for example, reducing the signal-to-noise ratio or introducing nonuniformity in the performance of the UDFPS across the area of the display, particularly as the optical UDFPS becomes larger.

SUMMARY

[0004] This disclosure describes methods and techniques for a distributed support structure for a large-area optical under-display fingerprint sensor. Using these techniques, a large-area optical under-display fingerprint sensor (large-area UDFPS or UDFPS), which enables the device to detect a user’s fingerprint anywhere on the display, can be implemented in or under a display of an electronic device. The distributed support structure (DSS) helps maintain a uniform gap between the UDFPS and a display (e.g, the display on which the user provides a fingerprint), which can improve performance, reliability, and accuracy of the UDFPS and improve the customer’s experience. Further, the techniques may also allow a manufacturer to use adhesives or other components that are easier to repair and rework, which can reduce damage to the display or the UDFPS and thereby decrease manufacturing and repair costs.

[0005] Aspects described below include an electronic device comprising: a display and an under-display fingerprint sensor, UDFPS, subassembly, which further comprises an optical fingerprint sensor, FPS, configured to capture an image of an object proximate a user-facing side of the display; an optical focusing mechanism, OFM; and a distributed support structure, DSS. The DSS is configured to maintain a substantially uniform gap between a surface of the display and the OFM and the DSS is disposed proximate a surface of the OFM that is configured to receive light reflected from the object proximate the userfacing side of the electronic device. The electronic device also includes an imaging processor configured to: obtain, from the FPS, the image of the object proximate the userfacing side of the display; convert the image to image data; determine, based on the image data, a static pattern within the image, the static pattern caused by the DSS; and remove the static pattern from the image.

[0006] Aspects described below also include a large-area under-display fingerprint sensor, UDFPS, assembly for an electronic device, comprising: an optical fingerprint sensor, FPS, configured to capture an image of an object proximate a user-facing side of a display of the electronic device; an optical focusing mechanism, OFM; and a distributed support structure, DSS. The DSS is configured to maintain a substantially uniform gap between a surface of the display and the OFM and is disposed proximate a surface of the OFM that is configured to receive light reflected from the object proximate the user-facing side of the electronic device.

[0007] Aspects described below also include a display assembly, comprising: a display; a patterned foundation layer, PFL, the PFL attached to a surface of the display that is opposite a user-facing surface of the display; and a large-area under-display fingerprint sensor, UDFPS subassembly. The UDFPS subassembly further comprises: an optical fingerprint sensor, FPS, configured to capture an image of an object proximate a userfacing side of the display; an optical focusing mechanism, OFM; and a distributed support structure, DSS. The DSS is configured to maintain a substantially uniform gap between a surface of the display and the OFM and is disposed between the PFL and the OFM.

[0008] Aspects described below also include a large-area under-display fingerprint sensor, UDFPS, assembly for an electronic device, comprising an optical fingerprint sensor, FPS, configured to capture an image of an object proximate a user-facing side of a display of the electronic device and a means for maintaining a substantially uniform gap between a surface of the display and the FPS.

[0009] This summary introduces simplified concepts for the distributed support structure for a large-area optical under-display fingerprint sensor, which is further described below in the Detailed Description and the Drawings. For ease of description, the disclosure may focus on systems that include an organic light-emitting diode (OLED) display and a large-area optical UDFPS to capture fingerprint images. The techniques, however, are not limited to the use of visible light, a large-area optical UDFPS, or an OLED display. Further, the techniques are not limited to fingerprint identification and may be used for other forms of biometric identification. For example, the techniques may be used for authentication or identification via another body part (e.g, the user’s palm, foot, or retinal image). This summary is not intended to identify essential features of the claimed subject matter, nor is it intended for use in determining the scope of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The details of one or more aspects of a distributed support structure for a large-area optical under-display fingerprint sensor are disclosed in this document with reference to the following drawings. The same numbers are used throughout the drawings to reference like features and components:

FIG. 1 illustrates an example environment in which a distributed support structure for a large-area optical under-display fingerprint sensor (UDFPS) can be implemented;

FIG. 2 illustrates an example implementation of an electronic device in which the distributed support structure for a large-area optical UDFPS can be implemented;

FIG. 3 illustrates an example large-area optical UDFPS assembly in which the distributed support structure for a large-area optical under-display fingerprint sensor can be implemented;

FIG. 4 illustrates example pattern configurations of the distributed support structure; FIG. 5 through FIG. 7-3 illustrate additional example large-area optical UDFPS assemblies in which the distributed support structure for a large-area optical under-display fingerprint sensor can be implemented;

FIG. 8-1 illustrates an example display assembly in which the distributed support structure for a large-area optical under-display fingerprint sensor can be implemented; and

FIG. 8-2 illustrates example implementations of the display assembly of FIG. 8-1.

DETAILED DESCRIPTION

Overview

[ooit] This document describes devices, apparatuses, and techniques that enable a distributed support structure for a large-area optical under-display fingerprint sensor. Generally, a large-area optical under-display fingerprint sensor (large-area optical UDFPS or UDFPS) enables an electronic device to detect a user’s fingerprint anywhere on a display of the electronic device (e.g, on an external, user-facing side of the display). Using the described techniques, the large-area optical UDFPS can be implemented in or under the display with a distributed support structure (DSS) that helps maintain a uniform gap between the UDFPS and the display, which can improve performance, reliability, and accuracy of the UDFPS. Further, the techniques may also allow a manufacturer to use adhesives or other components that are easier to repair and rework, which can reduce damage to the display or the UDFPS and thereby decrease manufacturing and repair costs.

[0012] Throughout this disclosure, examples are described in which a computing system (e.g, the electronic device) analyzes information (e.g, fingerprint images) associated with a user or the electronic device. The computing system uses the information associated with the user after the computing system receives explicit permission from the user to collect, store, or analyze the information. For example, in situations in which an electronic device recognizes or authenticates a user based on fingerprints, the user is provided with an opportunity to control whether programs or features of the electronic device or a remote system can collect and make use of the fingerprint for a current or subsequent authentication procedure.

[0013] Individual users, therefore, have control over what the computing system can and cannot do with fingerprint images and other information associated with the user. Information associated with the user (e.g, an enrolled image), if stored, is pre-treated in one or more ways so that personally identifiable information is removed before being transferred, stored, or otherwise used. For example, before the electronic device stores an enrolled image (also referred to as an “enrolled template”), the electronic device may encrypt the enrolled image. Pre-treating the data this way ensures the information cannot be traced back to the user, thereby removing any personally identifiable information that would otherwise be inferable from the enrolled image. Thus, the user has control over whether information about the user is collected and, if collected, how the information may be used by the computing system.

[0014] Consider an example large-area optical under-display fingerprint sensor that includes the described distributed support structure. In this example, an electronic device includes an organic light-emitting diode (OLED) display and a large-area optical underdisplay fingerprint sensor (UDFPS). The UDFPS includes an optical thin-film transistor (TFT)-based image sensor {e.g, an optical fingerprint sensor) that can capture an image of a user’s fingerprint through the display and an optical focusing mechanism (OFM) that can focus light reflected from the user’s finger onto the image sensor. In this example, the OFM is a thin-film micro-lens (ML) array, but the OFM may be another mechanism {e.g, a collimator or a filter). The UDFPS also includes a distributed support structure (DSS) that can maintain a uniform gap between the display and the UDFPS across the area of the display. In this example, the DSS is formed on the surface of the ML array, but in other implementations, the DSS can be attached to the UDFPS using different techniques. The UDFPS, including the OFM and the DSS, can be a single component that is laminated or encapsulated and ready to be attached to the display using, for example, a pressuresensitive adhesive.

[0015] The DSS is formed as a pattern or grid {e.g., a rows-and-columns grid or a triangular mesh) on the ML array. The height of the grid is greater than the height of the ML array so that when the OFM is attached to the display, the DSS forms a network of support under the display. Because many large-area UDFPS are attached to the display only along a perimeter of the UDFPS, the size and flexibility of the display can cause the display to flex. Similarly, when a user presses on the display to provide a fingerprint {e.g. , for authentication), the display can flex.

[0016] When the display flexes, the gap between the display and the UDFPS can vary across the area of the fingerprint {e.g, if the UDFPS is analogized to a camera, a non- uniform gap introduces variability in a “focal length” over the area of the display). The non-uniform gap can lead to, among other issues, reduced clarity and detail in the captured images, which may negatively affect the accuracy of a fingerprint-matching process by, for example, increasing the rate of false rejections or acceptances of a fingerprint used for authenticating a user. In contrast, the DSS helps maintain a uniform gap between the display and the large-area UDFPS, which can address these issues and improve performance of the fingerprint-matching process. The DSS may appear in captured fingerprint images as a fixed pattern, which can be removed from the image by an imaging processor using any of a variety of static-pattern algorithms.

[0017] In another example, the distributed support structure can be used with a patterned foundation layer (PFL). The PFL can be a physical component of the electronic device, including an electrical shielding layer, a grounding plane layer, or a combined shielding and grounding plane layer. In one example, the PFL is a copper and foam layer used in the electronic device for ESD protection and grounding. The PFL can be manufactured with a pattern that is the same as or similar to the pattern of the DSS. The PFL can be laminated or glued to the upper surface of the UDFPS, and the PFL-UDFPS assembly can be attached to the display (e.g., mechanically or with an adhesive).

[0018] In the examples that include the PFL, in addition to the advantages related to performance, the described techniques and apparatuses also provide advantages with respect to repairability (e.g., rework during manufacturing or in the after-market space). For example, if the UDFPS or the display is defective or damaged, it may be cost-effective (at an integration site and/or or post-sale) to separate the display and the UDFPS, repair the damaged component(s), and then reassemble the display and the UDFPS. Typically, a pressure-sensitive adhesive (PSA) or other adhesive is used to attach the large-area UDFPS to the perimeter of either the display or a (non-pattemed) grounding/shielding structure. When using the PFL, a manufacturer or assembly vendor may be able to use adhesives or other components that are easier to repair and rework (e.g., an adhesive that is easier or safer to remove), which can reduce damage to the display or the UDFPS and thereby decrease manufacturing and repair costs. For example, a liquid optically-clear adhesive (LOCA), a PSA, or another adhesive can be used to attach the large-area UDFPS to the perimeter of either the display or a (non-pattemed) grounding/shielding structure. When using the PFL, there is area (e.g., on a surface of the PFL) in addition to the perimeter edges that can be used as a gluing surface (sometimes referred to as a “wet” area). This allows other adhesives to be used, some of which may have better repairability characteristics (e.g., lower adhesive strength per unit of area may be acceptable because of the larger wet area). Further, adhesives that are more compatible with copper may be used to attach the DSS to the FPL. Thus, there may be less risk of damaging the display or the UDFPS when disassembling or separating them for rework or repair.

[0019] These are but a few examples of how the described techniques and devices may be used to enable the distributed support structure for a large-area optical underdisplay fingerprint sensor. Other examples and implementations are described throughout this document. The document now turns to an example environment, after which example systems, apparatuses, techniques, and components are described. Example Environment

[0020] FIG. 1 illustrates an example environment 100 in which a distributed support structure for a large-area optical under-display fingerprint sensor can be implemented. As illustrated, the example environment 100 includes an example electronic device 102, which is described with additional detail with reference to Fig. 2. A detail view 100-1 illustrates a section view A-A of the electronic device 102. The example electronic device 102 includes a display 104, a large-area optical under-display fingerprint sensor (large-area optical UDFPS or UDFPS) subassembly 106 (or UDFPS 106), and an imaging processor 108. The display 104 can be any of a variety of displays that can emit light toward an object near or proximate an external, user-facing side 104-1 of the electronic device 102 and allow light reflected from the object to pass through the display 104 to the UDFPS 106 (e.g, an object that is: approximately 1.5 mm from the user-facing side 104-1; approximately 0.5 mm from the user-facing side 104-1; or touching, abutting, or contacting the user-facing side 104-1). For example, the display 104 may be an organic light- emitting diode (OLED) display, such as a passive-matrix OLED (PMOLED) or an active-matrix OLED (AMOLED), or a liquid-crystal display (LCD). The UDFPS 106 may be attached to the display 104 using any suitable technique (e.g, an adhesive, a lamination technique, an encapsulation technique, or a mechanical attachment).

[0021] The UDFPS 106 (shown in FIG. 1 with pattern-filled rectangles) includes an optical fingerprint sensor (FPS) 110, an optical focusing mechanism (OFM) 112, and a distributed support structure (DSS) 114. The FPS 110 can be any of a variety of image sensors that can receive the light reflected from the object and capture an image of the object based on the reflected light. For example, the FPS 110 can be any sensor able to capture a high-resolution image (e.g, 500 Dots-Per-Inch (DPI), 700 DPI, or 1000 DPI). Depending on the imaging technology utilized to capture the fingerprint image, the FPS 110 may be an optical thin-film transistor (TFT) image sensor, a complementary metal- oxide-semiconductor (CMOS) image sensor, a charge-coupled device (CCD) image sensor, a capacitive image sensor, an ultrasonic image sensor, a quanta image sensor (QIS), and so forth. Thus, the described techniques and apparatuses are not limited to a specific imaging technology. The OFM 112 is a mechanism that can, among other functions, focus light reflected from the object (e.g, a user’s finger) onto the image sensor of the UDFPS 106 (e.g, the FPS 110). For example, the OFM 112 can be a collimator or a micro-lens (ML) array (e.g, a thin-film ML array). In some implementations, the OFM 112 may be omitted from UDFPS 106.

[0022] The DSS 114 (e.g, DSS 114-1, DSS 114-2) is a structure that can be used to maintain a substantially uniform gap between the OFM 112 and the display 104. The DSS 114 can be located between the display 104 and the OFM 112 (or the FPS 110). For example, the DSS 114 can be located on an upper surface of the OFM 112 (e.g, on or near a surface of the OFM 112 that is configured to receive the reflected light from the object proximate the user-facing side 104-1 of the electronic device 102). The DSS 114 can be made from support members that are attached to, integrated with, or formed on the OFM 112 and made from a variety of materials. For example, the DSS 114 can be made from polymers, plastics, acrylics, or composite materials. In some cases (e.g, in which the DSS 114 is formed on or integrated with the OFM 112), the DSS 114 can be made from a same or similar material as the OFM 112. As shown in the detail view 100-1, the DSS 114-1 has a rectangular cross-section and extends from the surface of the OFM 112 toward the display 104. In the example environment 100, the DSS 114-2 extends across the display 104 along a length of the display 104. The DSS 114 can be made in a variety of other shapes, patterns, and configurations, examples of which are described with additional details with reference to FIGs. 4 and 7-1.

[0023] The DSS 114 can be attached to the display 104 using an adhesive 116, for example, a pressure-sensitive adhesive (PSA) or an optically-clear adhesive (OCA). When the DSS 114 is attached to the display 104, the DSS 114 is effective to maintain the substantially uniform gap 118 between a surface 120 of the display 104 and the OFM 112 (or, in cases where the OFM 112 is omitted, between the surface 120 and the FPS 110). In some implementations, the adhesive 116 may be omitted, and the DSS 114 can be manufactured to extend toward the display 104 without touching the display 104. In this way, the DSS 114 can act as a hard stop that restricts the distance the display 104 can flex (e.g, based on the size and weight of the display 104 or when a finger is placed on the display), which also helps maintain the uniform gap 118. As noted, the uniformity of the uniform gap 118 can improve performance of the fingerprint-matching process by reducing degradation of clarity and detail in the captured images that may be introduced when the gap is non-uniform.

[0024] The imaging processor 108 can be any of a variety of electronic or computer processors. In FIG. 1, the imaging processor 108 is shown as a component in the device electronics 122 of the electronic device 102. In other implementations, the imaging processor 108 may be part of the UDFPS 106 or the display 104. The imaging processor 108 can obtain the image of the object proximate the user-facing side 104-1 of the display 104 from the UDFPS 106 or the FPS 110 and convert the image to image data. For example, the imaging processor 108 can obtain a fingerprint image and convert the fingerprint image to fingerprint-image data. Based on the image data, the imaging processor 108 can also determine a static pattern within the image caused by the DSS 114 and remove the static pattern from the image. For example, the DSS 114 can cause an area of the display 104, including rows, columns, and/or pixels, to be unusable or of reduced value for image-capture (e.g, by blocking emitted or reflected light). The unused or missing area can be addressed by an image-processing algorithm performed by the imaging processor 108.

[0025] In some implementations, the shape, pattern, and/or configuration of the DSS 114 can be registered by the UDFPS 106 as a static pattern (e.g, a pattern that does not change). Many fingerprint sensors can detect and remove common static patterns caused by scratches or cracks in the display using, for example, a matching algorithm to disable the static pattern. In some cases, the algorithm accounts for the image data from the area of the sensor with the static pattern by disabling the areas of the image-capture sensor (e.g. , the FPS 110) that may be blocked by the static pattern or by removing or disregarding that portion of the image data when performing the fingerprint-matching process. In some cases, the static pattern caused by the DSS 114 can be preprogrammed into the imaging processor 108. In other cases, the imaging processor 108 may use other techniques (e.g, machine-learning) to recognize static patterns similar to the DSS 114 pattern or cracks and scratches on the external user-facing surface (or side) 104-1 of the electronic device 102.

[0026] In some implementations (not shown in FIG. 1), the display 104 also includes a patterned foundation layer (PFL). The PFL may include one or more of an electrical shielding layer, a grounding plane layer, or an integrated electrical shielding layer and grounding plane layer. The PFL can be formed in a shape, pattern, and/or configuration that approximately matches that of the DSS 114. In these implementations, the DSS 114 can be attached to the PFL to maintain the uniform gap 118 between the surface 120 the OFM 112. Example implementations of a display (e.g, the display 104) that include the PFL are illustrated with additional detail with reference to FIG. 8-1 and FIG. 8-2. In other implementations, the PFL may be included with the UDFPS 106. Example implementations of a UDFPS (e.g, the UDFPS 106) that include the PFL are illustrated with additional detail with reference to FIGs. 7-1 through 7-3.

[0027] In more detail, consider FIG. 2, which illustrates an example implementation

200 of the electronic device 102 (including the display 104 and the UDFPS 106) in which the distributed support structure for a large-area optical under-display fingerprint sensor can be implemented. The electronic device 102 of FIG. 2 is illustrated with a variety of example devices, including a smartphone 102-1, a tablet 102-2, a laptop 102-3, a desktop computer 102-4, a home automation and control system 102-5, a computing watch 102-6, a refrigerator 102-7, and an automobile 102-8. The electronic device 102 can also include other devices, such as televisions, entertainment systems, audio systems, drones or other remotely controlled vehicles, track pads, drawing pads, netbooks, e-readers, home security systems, and other home appliances. Note that the electronic device 102 can be wearable, non-wearable but mobile, or relatively immobile (e.g, desktops or appliances).

[0028] The electronic device 102 of FIG. 2 includes the DS S 114 (shown separately from the UDFPS 106 for clarity), a computer processor 202, a computer-readable media 204 (CRM 204), one or more sensor components 206, and a communication and input/output (I/O) component 208. The computer processor 202 may include any combination of one or more controllers, microcontrollers, processors, microprocessors, hardware processors, hardware processing units, digital signal processors, graphics processors, graphics processing units, and the like. The computer processor 202 may be an integrated processor and memory subsystem (e.g, implemented as a “system-on-chip”), which processes computer-executable instructions to control operations of the electronic device 102. Other programs, services, and applications (not shown) can be implemented as computer-readable instructions on the CRM 204, which can be executed by the computer processors 202 to provide functionalities described herein. The computer processor 202 and the CRM 204 may include dedicated memory media and storage media (not shown in FIG. 2).

[0029] The CRM 204 is configured as persistent and non-persistent storage of executable instructions (e.g, firmware, software, applications, modules, programs, functions) and data (e.g, user data, operational data, online data) to support execution of the executable instructions. Examples of the CRM 204 include volatile memory and nonvolatile memory, fixed and removable media devices, and any suitable memory device or electronic data storage that maintains executable instructions and supporting data. The CRM 204 can include various implementations of random-access memory (RAM), readonly memory (ROM), flash memory, and other types of storage memory in various memory device configurations. The CRM 204 excludes propagating signals. The CRM 204 may be a solid-state drive (SSD) or a hard disk drive (HDD).

[0030] The CRM 204 may also include an application 210, which can be software, an applet, a peripheral, or another entity that requires or prefers authentication of a user. For example, the application 210 can be a secured component of the electronic device 102 or an access entity to secure information accessible from the electronic device 102. The application 210 can be part of an operating system (OS) that generally prevents access to the electronic device 102 until the user’s fingerprint is identified. The application 210 may execute partially or wholly on the electronic device 102 or in “the cloud” (e.g, on a remote device accessed through the Internet).

[0031] The sensor components 206 include the UDFPS 106, which includes the OFM 112 (shown separately for clarity). In some implementations, the sensor components 206 also include an imaging processor 212 (e.g, the imaging processor 108 described with reference to FIG. 1). The imaging processor 212 can be used to obtain an image of a user’s fingerprint (or another biometric image) and convert the image to image data. In other implementations, the functions of the imaging processor 212 may be performed by another component (e.g, the computer processors 202 or the fingerprint identification system 214). In addition to the UDFPS 106, the sensor components 206 may include other sensors for obtaining contextual information (e.g, sensor data) indicative of operating conditions (virtual or physical) of the electronic device 102 or an environment around the electronic device 102. The electronic device 102 monitors the operating conditions based in part on sensor data generated by the sensor components 206. In addition to the components described with reference to FIG. 1, other examples of the sensor components 206 include various types of cameras (e.g, optical, infrared), radar sensors, inertial measurement units, movement sensors, temperature sensors, position sensors, proximity sensors, light sensors, infrared sensors, moisture sensors, or pressure sensors.

[0032] The electronic device 102 of FIG. 2 also includes a fingerprint identification system 214 and a secured data store 216. Using the fingerprint identification system 214, a user may create an enrolled image (e.g, a user-specific fingerprint image that is used to match against later fingerprint images made by users attempting to access the electronic device 102 or applications operating on the electronic device 102). The fingerprint identification system 214 records and stores (e.g, in the secured data store 216) the enrolled image in advance during a coordinated setup session with the electronic device 102 and a particular user. For example, the electronic device 102 can instruct the user to press a finger on a display of the electronic device 102 one or more times until the fingerprint identification system 214 has an accurate image of the user’s fingerprint (or fingerprints, palm prints), which the electronic device 102 retains as the enrolled image.

[0033] The communication and input/output (I/O) component 208 provides connectivity to the electronic device 102 and other devices and peripherals and can operate as an input device and/or an output device. The communication and I/O component 208 includes data network interfaces that provide connection and/or communication links between the device and other data networks, devices, or remote systems (e.g, servers). The communication and I/O component 208 couples the electronic device 102 to a variety of different types of components, peripherals, or accessory devices. Data input ports of the communication and I/O component 208 receive data, including image data, user inputs, communication data, audio data, video data, and the like. The communication and I/O component 208 enables wired or wireless communicating of device data between the electronic device 102 and other devices, computing systems, and networks. Transceivers of the communication and I/O component 208 enable cellular phone communication and other types of network data communication. This document now turns to various example implementations of the distributed support structure for a large-area optical under-display fingerprint sensor.

Example Implementations of the Distributed Support Structure

[0034] FIG. 3 illustrates an example large-area optical under-display fingerprint sensor assembly 300 in which the distributed support structure for a large-area optical under-display fingerprint sensor can be implemented. The example UDFPS assembly 300 includes an optical fingerprint sensor (FPS) 302, an optical focusing mechanism (OFM) 304, and a distributed support structure (DSS) 306. The example FPS 302 can be any of a variety of image sensors that can capture an image of an object near a user-facing side of a display (e.g, the external, user-facing side 104-1 of the display 104), such as a user’s fingerprint. For example, the FPS 302 can be the FPS 110. The example OFM 304 can be any of a variety of mechanisms that can focus the reflected light onto the image sensor of the FPS 302 (e.g, the OFM 112, a thin-film micro-lens array, or a collimator). The OFM 304 can be atached to the FPS 302 using any suitable technique (e.g, an adhesive, a lamination technique, an encapsulation technique, or a mechanical atachment).

[0035] The DSS 306 is a distributed structure that can be used to maintain a substantially uniform gap between the example OFM 304 and a display (e.g, the DSS 306 can be the DSS 114). For example, the DSS 306 can be disposed proximate a surface 308 of the OFM 304 that can receive light reflected from one or more objects proximate or near the user-facing side of an electronic device (e.g, the external, user-facing side 104-1 of the electronic device 102). As described with reference to the DSS 114 of FIG. 1, the DSS 306 can be made from support members that are atached to, integrated with, or formed on the OFM 304, and the DSS 306 can be made from a variety of materials. The DSS 306 can be atached to the display using a variety of techniques (as described with reference to the DSS 114 of FIG. 1) in a way that can maintain a substantially uniform gap between an internal surface of the display (e.g, an internal surface that is opposite an external surface, such as the external, user-facing side 104-1 of the electronic device 102) and the OFM 304 or the FPS 302.

[0036] As shown in FIG. 3, the DSS 306 is a rows-and-columns grid patern that has a generally rectangular cross-section and extends from the surface of the OFM 304. Other DSS-patem configurations of the DSS 306 may include: a large-area grid patern that has a patern-area that is approximately equal to an area of the OFM 304; one or more smallarea grid paterns with each respective small-area grid patern covering less than the area of the OFM 304 and each respective small-area grid patern of the one or more small-area grid paterns discontinuous from the other respective small-area grid paterns; one or more pillars; or at least one pillar and at least one small-area grid patern.

[0037] In any DSS-patern configuration described in this document, a grid or mesh patern can take a variety of shapes (e.g, a columns-and-rows grid or a triangular mesh). The support members may have a variety of widths and spacings. For example, the support members can have a width of between approximately 30 micrometers (microns or pm) and approximately 400 pm (e.g, approximately 50 pm, approximately 150 pm, or approximately 300 pm). A distance between the support members may be between approximately 5 millimeters (mm) and approximately 20mm (e.g, approximately 10mm or approximately 15mm). Pillars may have any of a variety of cross-sectional shapes, including generally circular, rectangular, trapezoidal, hexagonal, or triangular. In some cases, rather than measuring width in mm or pm, the area taken up by support members of the DSS 306 may be specified using pixels. For example, a support member may have a width of approximately one pixel to approximately seven pixels (e.g, approximately two pixels or approximately five pixels).

[0038] Consider FIG. 4, which illustrates example DSS-patern configurations 400 of the DSS 306 (or any other DSS described in this document). In the example configurations 400, the DSS 306 is formed by support members and integrated with the OFM 304. The DSS-patern configuration 400-1 is a large-area grid patern that has a patern-area that is approximately equal to an area of the OFM 304. The DSS-patern configuration 400-2 includes two small-area grid patterns, each covering less than the area of the OFM 304 discontinuous with respect to each other. The DSS-patern configuration 400-3 includes five pillars 402 with generally circular cross-sections. The DSS-patem configuration 400-4 includes one small-area grid patern and three pillars 404 with generally rectangular cross sections. For clarity, in the DSS-patem configurations 400-3 and 400-4, the pillars are indicated using dashed-line rectangles.

[0039] As shown in FIG. 4, the example DSS-patem configurations 400 are shown as including a perimeter portion. In other implementations (e.g, the DSS 306 shown in FIG. 3), the DSS-patem configuration does not include the perimeter portion. For example, the DSS-patem configuration 400-3 may be used without a perimeter, which can reduce the thickness of the stack. In this implementation, the FPS 302 and OFM 304 may be atached to the display using a frame-atachment technique. The DSS 306 can be configured with a modified version of the DSS-patem configuration 400-3 (not shown in FIG. 4) in which pillars 402 are located in areas where users are more likely to touch the screen (e.g, in the center or a comer). In this way, even when thickness constraints may limit the use of the full DSS 306, the pillars can help reduce negative effects on performance of the UDFPS that may be introduced by a user pressing on the screen.

[0040] FIG. 5 illustrates another example UDFPS assembly 500. A detail view 500-1 illustrates the example UDFPS assembly 500 as a section view B-B of another electronic device 502 (e.g, the electronic device 102). For clarity in the detail view 500- 1, the components are not to scale, and some components of the electronic device 502 are omited. As shown, the example UDFPS assembly 500 includes an FPS 504, an OFM 506, a DSS 508, and a display 510. For example, the FPS 504 can be the FPS 110 or the FPS 302. The DSS 508 can be any of the DSS components described in this document (e.g, the DSS 114 or the DSS 306). The display 510 can be any of a variety of displays, including the display 104.

[0041] In the example UDFPS assembly 500, the OFM 506 is a thin-film micro-lens

(ML) array. The DSS 508 is integrated with the ML array. In other implementations, the DSS 508 can be attached to or formed on the ML array. The DSS 508 is attached to the display 510 of the electronic device 502 effective to maintain a substantially uniform gap 512 between a surface 514 of the display 510 and the ML array (e.g. , the OFM 506). The OFM 506 can be attached to the FPS 504 using a variety of techniques, including using a liquid optically-clear adhesive (LOCA), lamination, or encapsulation. Similarly, the DSS 508 can be attached to the display 510 using an adhesive 516 (e.g, a PSA or a LOCA) or a mechanical technique.

[0042] In some implementations (not shown in FIG. 5), all or part of the DSS 508 is not attached to the display 510 and only extends toward, but does not touch, the surface 514. In this implementation, the unattached support members act to prevent excessive flexing of the display (e.g, when a user presses down on the device). For example, in the DSS-pattem configuration 400-4 described with reference to FIG. 4, the small-area grid pattern can be attached to the surface 514, and the pillars 404 can be unattached. Further, in other implementations, one or more “high-traffic” areas of the display may be determined (e.g, areas where users are more likely to press than in other areas). In this case, the DSS 508 can include an attached grid or mesh portion and one or more unattached pillars in the high-traffic area. [0043] FIG. 6 illustrates another example UDFPS assembly 600. In a detail view 600-1, the example UDFPS assembly 600 is illustrated as a section view C-C of another electronic device 602 (e.g, the electronic device 102). For clarity in the detail view 600-1, the components are not drawn to scale, and some components of the electronic device 602 are omitted. As shown, the example UDFPS assembly 600 includes an FPS 604, an OFM 606, a DSS 608, and a display 610. For example, the FPS 604 can be the FPS 110, the FPS 302, or the FPS 504. The DSS 608 can be any of the DSS components described in this document (e.g, the DSS 114, the DSS 306, or the DSS 508). The display 610 can be any of a variety of displays, including the display 104.

[0044] In the example UDFPS assembly 600, the OFM 606 is a collimator. The DSS 608 can be attached to the collimator using any of a variety of techniques, including an adhesive 612 (e.g, a PSA or a LOCA). In some implementations, the DSS 608 may be integrated with, or formed from, the OFM 606. The DSS 608 is attached to the display 610 of the electronic device 602 effective to maintain a substantially uniform gap 614 between a surface 616 of the display 610 and the collimator (e.g, the OFM 606). The OFM 606 can be attached to the FPS 604 using a variety of techniques, including using a LOCA, lamination, or encapsulation. Similarly, the DSS 608 can be attached to the display 610 using a PSA, a LOCA, or another technique (e.g, a mechanical technique). As described with reference to FIG. 5, in some implementations (not shown in FIG. 6), all or part of the DSS 608 is not attached to the display 610 but only extends toward, but does not touch, the surface 616. [0045] In some implementations (not shown), the UDFPS assembly 300 may also include a patterned foundation layer (PFL). The PFL may include or be part of an electrical shielding layer, a grounding plane layer, or a combined electrical shielding and grounding plane layer. The PFL may be formed in a PFL-pattem configuration that approximately matches the DSS-pattem configuration, as described with reference to FIG. 4. The PFL can be attached to the display as part of a display subassembly (e.g, as part of any of the display 104, the display 510, or the display 610). In other implementations, the PFL can be attached to the UDFPS (e.g, as a part of the UDFPS assembly 300) or be a separate component that is attached to the display and to the DSS 306 (and/or the OFM 304) in a way that maintains a substantially uniform gap between a surface of the display and the OFM 304 (e.g, the uniform gap 118 described with reference to FIG. 1).

[0046] When the PFL is integrated with the display subassembly, the PFL includes a foam or other cushioning layer, which is attached to the display using an adhesive layer (e.g, a PSA or a LOCA). The foam layer can be between approximately 80 pm and approximately 120 pm (e.g, approximately 100 pm). The foam layer is covered with a thin layer of copper that can be between approximately 20 pm and approximately 60 pm (e.g, approximately 40 pm). The entire structure (foam and copper) can be patterned or formed to be the foundation for the DSS.

[0047] For example, consider FIG. 7-1, which illustrates another example large-area

UDFPS assembly 700 that includes an FPS 702, an OFM 704, a DSS 706, and a PFL 708. The FPS 702 can be any of the DSS described in this document (e.g, the FPS 110, the FPS 302, the FPS 504, or the FPS 604). Similarly, the OFM 704 can be any of the OFM described in this document (e.g, a collimator, a thin-film ML array, or any of the OFM 112, 304, 506, or 606) and the DSS 706 can be any of the DSS 114, 306, 508, or 608. As shown in FIG. 7-1, the PFL 708 also has a PFL-pattem configuration (a rows-and-columns grid) that approximately matches the DSS-pattem configuration of the DSS 706. The PFL- pattem configuration and the DSS-pattem configuration can be a variety of configurations (e.g, as described with reference to FIG. 4). The example UDFPS assembly 700 can be attached to a display (e.g, the display 104) to enable the DSS 706 and the PFL 708 to maintain the uniform gap 118.

[0048] In FIG. 7-2, an example implementation 700-1 of the UDFPS assembly 700 is illustrated as a section view D-D of another electronic device 710 (e.g, the electronic device 102). For clarity in the section view D-D, the components are not drawn to scale, and some components of the electronic device 710 are omitted. As shown, the example UDFPS implementation 700-1 includes the FPS 702, the OFM 704-1, the DSS 706, the PFL 708, and a display 712. The PFL 708 is disposed between the DSS 706 and the display 712. The display 712 can be any of a variety of displays (e.g, the display 104).

[0049] In the example implementation 700-1, the OFM 704-1 is a thin-film ML array. The DSS 706 can be attached to, integrated with, or formed on the ML array. The DSS 706 is attached to the PFL 708 effective to maintain a substantially uniform gap 714 between a surface 716 of the display 712 and the ML array (e.g, the OFM 704-1) when the PFL 708 is attached to the display 712. The surface 716 can be a surface that is opposite a user-facing surface of the display 712 (e.g, opposite the external, user-facing side 104-1 of the electronic device 102). The OFM 704-1 can be attached to the FPS 702 using a variety of techniques, including using a LOCA, lamination, or encapsulation. Similarly, the PFL 708 can be attached to the display 712 using an adhesive (e.g, a PSA or a LOCA) or a mechanical technique. As described with reference to FIG. 5, in some implementations (not shown in FIG. 7-2), all or part of the DSS 706 is not attached to the display 712. Rather, the DSS 706 only extends toward, but does not touch, the surface 716. Further, as noted with reference to FIG. 4, some DSS-pattem configurations may include pillars or a combination of pillars and small-area grid patterns. In these cases, the PFL 708 may not be disposed between the DSS 706 and the display 712, and some or all of the DSS 706 may extend to touch or nearly touch the surface 716.

[0050] In FIG. 7-3, another example implementation 700-2 of the UDFPS assembly 700 is illustrated as a section view E-E of another electronic device 718 (e.g, the electronic device 102). For clarity in the section view E-E, the components are not drawn to scale and some components of the electronic device 718 are omitted. As shown, the example UDFPS implementation 700-2 includes the FPS 702, the OFM 704-2, the DSS 706, the PFL 708, and the display 712. The PFL 708 is disposed between the DSS 706 and the display 712. The display 712 can be any of a variety of displays (e.g, the display 104).

[0051] In the example implementation 700-2, the OFM 704-2 is a collimator. The DSS 706 can be attached to, integrated with, or formed on the collimator. The DSS 706 is attached to the PFL 708 in a way that maintains a substantially uniform gap 720 between the surface 716 of the display 712 and the collimator (e.g, the OFM 704-2) when the PFL 708 is attached to the display 712. The OFM 704-2 can be attached to the FPS 702 using a variety of techniques, including using a LOCA, lamination, or encapsulation. Similarly, the PFL 708 can be attached to the display 712 using an adhesive (e.g, a PSA or a LOCA) or a mechanical technique. As described with reference to FIG. 5, in some implementations (not shown in FIG. 7-3), all or part of the DSS 706 is not attached to the display 712 but only extends toward, without touching, the surface 716. Further, as noted with reference to FIG. 4, some DSS-pattern configurations may include pillars or a combination of pillars and small-area grid patterns. In these cases, the PFL 708 may not be disposed between the DSS 706 and the display 712, and some or all of the DSS 706 may extend to touch or nearly touch the surface 716.

[0052] FIG. 8- 1 illustrates an example display assembly 800 in which the distributed support structure for a large-area optical under-display fingerprint sensor can be implemented. The example display assembly 800 includes a display 802, a PFL 804, and a large-area UDFPS subassembly 806 (or UDFPS 806). The display 802 can be any of the displays described in this document (e.g, the display 104). For clarity with respect to the PFL 804, the display 802 is shown with dashed lines. The PFL 804 can be any of the PFL described with reference to FIGs. 1, 3, and/or 7-1 through 7-3. In some implementations, the PFL 804 is attached to a surface of the display 802 that is opposite a user-facing surface of the display 802 using an adhesive layer (e.g, a PSA or a LOCA) and with the copper surface of the PFL 804 facing the UDFPS 806.

[0053] The UDFPS 806 can be any of a variety of under-display fingerprint sensors (e.g, the UDFPS 106, the UDFPS assembly 300, or the UDFPS assembly 700). As shown, the UDFPS 806 includes an FPS 808, an OFM 810, and a DSS 812. The FPS 808 can be any optical fingerprint sensor that can capture images of objects proximate a user-facing side of the display 802, such as the external, user-facing side 104-1. For example, the FPS

808 can be the FPS 110, the FPS 302, the FPS 504, the FPS 604, or the FPS 702. The

OFM 810 is attached to the FPS 808 and can be any of the OFM described in this document (e.g., a collimator, a thin-film ML array, or any of the OFM 112, 304, 506, 606, or 704). The DSS 812 is attached to the OFM 810 (e.g., between the PFL 804 and the OFM 810) in a way that maintains a substantially uniform gap between a surface of the display 802 and the OFM 810. The DSS 812 can be any of the DSS described herein (e.g., the DSS 114, 306, 508, 608, or 706).

[0054] In some implementations, the components of the example display assembly 800 can be attached together as a stack using a variety of methods. For example, one or more of a lamination technique, an encapsulation technique, an adhesive, or a mechanical technique. In this way, the display 802, the PFL 804, and the UDFPS 806 can be a standalone display module (e.g., protected from contamination and or light-leakage) that can be integrated with various electronic devices.

[0055] The DSS 812 can be made from support members, which may be integrated with, formed from, or attached to the OFM 810 (e.g, similar to the DSS 306 of FIG. 3). The DSS 812 can be formed in any of a variety of DSS-pattem configurations including, for example, a large-area grid pattern that has a pattern-area that is approximately equal to an area of the OFM 810. Other examples include one or more small-area grid patterns with each respective small-area grid pattern covering less than the area of the OFM 810 and each respective small-area grid pattern of the one or more small-area grid patterns discontinuous from the other respective small-area grid patterns, one or more pillars, or at least one pillar and at least one small-area grid pattern.

[0056] The PFL 804 can be an electrical shielding layer, a grounding plane layer, or a combined electrical shielding and grounding plane layer. The PFL 804 can be formed in a PFL-pattem configuration that approximately matches the DSS-pattem configuration (e.g, as shown in FIG. 4).

[0057] Consider FIG. 8-2, which illustrates additional example implementations 800-1 and 800-2 of the display assembly 800. The example implementations 800-1 and 800-2 are shown as section views F-F. For clarity in the detail views 800-1 and 800-2, the components are not drawn to scale. The example implementation 800-1 includes the display 802, the PFL 804, and the large-area UDFPS subassembly 806 (or UDFPS 806). The PFL 804 is disposed between the DSS 812 and the display 802.

[0058] In the example implementation 800-1, the OFM 810-1 is a thin-film ML array. The DSS 812 can be attached to, integrated with, or formed on the ML array. The DSS 812 is attached to the PFL 804 in a way that maintains a substantially uniform gap 814 between a surface 816 of the display 802 and the ML array (e.g, the OFM 810-1) when the PFL 804 is attached to the display 802. The OFM 810-1 can be attached to the FPS 808 using a variety of techniques, including using a LOCA, lamination, or encapsulation. Similarly, the PFL 804 can be attached to the display 802 using an adhesive (e.g, a PSA or a LOCA) or a mechanical technique.

[0059] In the example implementation 800-2, the OFM 810-2 is a collimator. The

DSS 812 can be attached to, integrated with, or formed on the collimator. The DSS 812 is attached to the PFL 804 in a way that maintains a substantially uniform gap 820 between a surface 816 of the display 802 and the collimator (e.g, the OFM 810-2) when the PFL 804 is attached to the display 802. The OFM 810-2 can be attached to the FPS 808 using a variety of techniques, including using a LOCA, lamination, or encapsulation. Similarly, the PFL 804 can be attached to the display 802 using an adhesive (e.g, a PSA or a LOCA) or a mechanical technique.

[0060] In some implementations (not shown in FIG. 8-2), all or part of the DSS 812 is not attached to the display 802 (e.g. , similar to FIG. 5). Rather, the DSS 812 only extends toward, but does not touch, the surface 816. Further, as noted with reference to FIG. 4, some DSS-pattem configurations may include pillars or a combination of pillars and smallarea grid patterns. In these cases, the PFL 804 may not be disposed between the DSS 812 and the display 802, and some or all of the DSS 812 may extend to touch or nearly touch the surface 816.

[0061] In implementations that include the PFL 708 or 804 as described with reference to FIGs. 7-1 through 7-3, FIG. 8-1, and FIG. 8-2, a manufacturer or assembly vendor may be able to use adhesives or other components that are easier to repair and rework (e.g, an adhesive that is easier or safer to remove), which can reduce damage to the display or the UDFPS and thereby decrease manufacturing and repair costs. For example, a LOCA or PSA can be used to attach the large-area UDFPS to the perimeter of either the display or a (non-pattemed) grounding/shielding structure. When using the PFL 708, there is area in addition to the area of the perimeter edges that can be used as a gluing surface (sometimes referred to as a wet area). This allows other adhesives to be used, some of which may have beter repairability characteristics (e.g., lower adhesive strength per unit of area may be acceptable because of the larger wet area). Further, adhesives that are more compatible with copper may be used to atach the DSS to the FPL. Thus, there may be less risk of damaging the display or the UDFPS when disassembling or separating them for rework or repair.

[0062] In some implementations of the display assembly 800, the PFL 804 may be omited or included at another location in the electronic device. Example implementations of the distributed support structure for a large-area optical under-display fingerprint sensor that do not include an FPL are described with reference to FIGs. 3, 5, and 6.

[0063] Several additional examples of the described techniques and apparatuses are described below.

[0064] In one example, a large-area under-display fingerprint sensor, UDFPS, assembly for an electronic device, comprises an optical fingerprint sensor, FPS, configured to capture images of objects proximate a user-facing side of a display of the electronic device; an optical focusing mechanism, OFM; and a distributed support structure, DSS, disposed proximate a surface of the OFM that is configured to receive light reflected from the objects proximate the user-facing side of the electronic device and configured to maintain a substantially uniform gap between a surface of the display and the OFM.

[0065] The DSS may comprise support members formed in a DSS-patem configuration. The DSS-patem configuration may comprise a large-area grid patern. The large-area grid patern may have a patern-area that is approximately equal to an area of the OFM. The DSS-patem configuration may comprise one or more small-area grid paterns. Each respective small-area grid patern may cover less than the area of the OFM. Each respective small-area grid patern of the one or more small-area grid paterns may be discontinuous with respect to each other respective small-area grid patern of the one or more small-area grid paterns. The DSS-patem configuration may comprise one or more pillars. The DSS-patem configuration may comprise at least one pillar and at least one small-area grid patern.

[0066] The UDFPS assembly may include a paterned foundation layer, PFL. The PFL may comprise an electrical shielding layer, a grounding plane layer, or an integrated electrical shielding layer and grounding plane layer. The PFL may be atached to the OFM and formed in a PFL-patem configuration that approximately matches the DSS-patern configuration.

[0067] The OFM may comprise a thin-film micro-lens, ML, array. The DSS may be integrated with the ML array. The DSS may be configured to be atached to the PFL, the PFL disposed between the OFM and a display of the electronic device.

[0068] The OFM may comprise a collimator. The DSS may be atached to the collimator and configured to be atached to the PFL. The PFL may be disposed between the DSS and a display of the electronic device. The DSS may be atached to the collimator and configured to be attached to a display of the electronic device effective to maintain a substantially uniform gap between a surface of the display and the collimator

[0069] The OFM may comprise a thin-film micro-lens, ML, array. The DSS may be integrated with the ML array and configured to be attached to a display of the electronic device effective to maintain a substantially uniform gap between a surface of the display and the ML array.

[0070] In another example, an electronic device comprises a display and an underdisplay fingerprint sensor, UDFPS, subassembly. The UDFPS subassembly may comprise an optical fingerprint sensor, FPS, configured to capture images of objects proximate a user-facing side of the display, an optical focusing mechanism, OFM, and a distributed support structure, DSS, disposed proximate a surface of the OFM that is configured to receive light reflected from the objects proximate the user-facing side of the electronic device and configured to maintain a substantially uniform gap between a surface of the display and the OFM. The electronic device may comprise an imaging processor configured to obtain, from the FPS, the images of the objects proximate the user-facing side of the display, convert the images to image data, determine, based on the image data, a static pattern within the image, the static pattern caused by the DSS, and remove the static pattern from the image.

[0071] The DSS may comprise support members, integrated with the OFM, and formed in a DSS-pattem configuration. The DSS-pattern configuration may comprise a large-area grid pattern. The large-area grid pattern may have a pattern-area that is approximately equal to an area of the OFM. The DSS-pattem configuration may comprise one or more small-area grid patterns. Each respective small-area grid pattern may cover less than the area of the OFM. Each respective small-area grid pattern of the one or more small-area grid patterns may be discontinuous with respect to each other respective smallarea grid pattern of the one or more small-area grid patterns. The DSS-pattem configuration may comprise at least one pillar. The DS S -pattern configuration may comprise at least one pillar and at least one small-area grid pattern.

[0072] The display may include a patterned foundation layer, PFL, the PFL comprising an electrical shielding layer, a grounding plane layer, or an integrated electrical shielding layer and grounding plane layer. The PFL may be formed in a PFL-pattem configuration that approximately matches the DSS-pattem configuration.

[0073] The OFM may comprise a thin-film micro-lens, ML, array. The DSS may be integrated with the ML array and may be configured to be attached to the PFL. The PFL may be disposed between the OFM and the display.

[0074] The OFM may comprise a collimator. The DSS may be attached to the collimator and may be configured to be attached to the PFL. The PFL may be disposed between the DSS and the display.

[0075] The OFM may comprise a thin-film micro-lens, ML, array. The DSS may be integrated with the ML array and may be configured to be attached to the display, effective to maintain a substantially uniform gap between a surface of the display and the ML array.

[0076] The OFM may comprise a collimator. The DSS may be attached to the collimator and configured to be attached to the display, effective to maintain a substantially uniform gap between a surface of the display and the collimator.

[0077] In another example, a display assembly comprises a display and a patterned foundation layer, PFL. The PFL may be attached to a surface of the display that is opposite a user-facing surface of the display. The display assembly comprises a large-area underdisplay fingerprint sensor, UDFPS subassembly. The UDFPS subassembly further comprises an optical fingerprint sensor, FPS, configured to capture images of objects proximate a user-facing side of the display, an optical focusing mechanism, OFM, and a distributed support structure, DSS. The DSS is disposed between the PFL and the OFM and configured to maintain a substantially uniform gap between a surface of the display and the OFM.

[0078] The display, the PFL, and the UDFPS may be laminated together, effective to form a display module.

[0079] The DSS may comprise support members formed in a DSS-pattem configuration. The DSS-pattem configuration may comprise a large-area grid pattern, the large-area grid pattern having a pattern-area that is approximately equal to an area of the OFM. The DSS-pattem configuration may comprise one or more small-area grid patterns, each respective small-area grid pattern covering less than the area of the OFM and each respective small-area grid pattern of the one or more small-area grid patterns discontinuous with respect to each other respective small-area grid pattern of the one or more small-area grid patterns. The DSS-pattem configuration may comprise at least one pillar. The DSS- pattem configuration may comprise at least one pillar and at least one small-area grid pattern.

[0080] The PFL may comprise an electrical shielding layer, a grounding plane layer, or an integrated electrical shielding layer and grounding plane layer. The PFL may be formed in a PFL-pattem configuration that approximately matches the DSS-pattem configuration. [0081] The OFM may comprise a thin-film micro-lens, ML, array. The DSS may be integrated with the ML array and configured to be attached to the PFL, the PFL disposed between the ML array and the display.

[0082] The OFM may comprise a collimator. The DSS may be attached to the collimator and configured to be attached to the PFL, the PFL disposed between the collimator and the display.

CONCLUSION

[0083] Although implementations of techniques for, and apparatuses enabling, a distributed support structure for a large-area optical under-display fingerprint sensor have been described in language specific to features and/or methods, it is to be understood that the subject of the appended claims is not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed as example implementations that enable the distributed support structure for a large-area optical underdisplay fingerprint sensor.

Claims

CLAIMS What is claimed:

1. A large-area under-display fingerprint sensor, UDFPS, assembly for an electronic device, comprising: an optical fingerprint sensor, FPS, configured to capture an image of an object proximate a user-facing side of a display of the electronic device; an optical focusing mechanism, OFM; and a distributed support structure, DSS, configured to maintain a substantially uniform gap between a surface of the display and the OFM, the DSS disposed proximate a surface of the OFM that is configured to receive light reflected from the object proximate the userfacing side of the electronic device.

38

2. The UDFPS assembly of claim 1, wherein the DSS comprises support members formed in a DSS-pattem configuration, the DSS-pattem configuration comprising: a large-area grid pattern, the large-area grid pattern having a pattern-area that is approximately equal to an area of the OFM; or one or more small-area grid patterns, each respective small-area grid pattern covering less than the area of the OFM and each respective small-area grid pattern of the one or more small-area grid patterns discontinuous with respect to each other respective small-area grid pattern of the one or more small-area grid patterns; or one or more pillars; or at least one pillar and at least one small-area grid pattern.

3. The UDFPS assembly of claim 2, wherein: the UDFPS assembly includes a patterned foundation layer, PFL, the PFL comprising an electrical shielding layer, a grounding plane layer, or an integrated electrical shielding layer and grounding plane layer; and the PFL is attached to the OFM and formed in a PFL-pattem configuration that approximately matches the DSS-pattem configuration.

39

4. The UDFPS assembly of claim 3, wherein: the OFM comprises a thin-film micro-lens, ML, array; and the DSS is integrated with the ML array and configured to be attached to the PFL, the PFL disposed between the OFM and a display of the electronic device.

5. The UDFPS assembly of claim 3, wherein: the OFM comprises a collimator; and the DSS is attached to the collimator and configured to be attached to the PFL, the PFL disposed between the DSS and a display of the electronic device.

6. The UDFPS assembly of claim 1 or claim 2, wherein: the OFM comprises a thin-film micro-lens, ML, array; and the DSS is integrated with the ML array and configured to be attached to a display of the electronic device effective to maintain a substantially uniform gap between a surface of the display and the ML array.

7. The UDFPS assembly of claim 1 or claim 2, wherein: the OFM comprises a collimator; and the DSS is attached to the collimator and configured to be attached to a display of the electronic device effective to maintain a substantially uniform gap between a surface of the display and the collimator.

40

8. A display assembly, comprising: a display; and the UDFPS assembly of any preceding claim.

9. The display assembly of claim 8, further comprising a patterned foundation layer, PFL, the PFL attached to a surface of the display that is opposite a user-facing surface of the display, the DSS disposed between the PFL and the OFM and configured to maintain a substantially uniform gap between a surface of the display and the OFM.

10. The display assembly of claim 9 when comprising the UDFPS of claim 2, wherein: the PFL comprises an electrical shielding layer, a grounding plane layer, or an integrated electrical shielding layer and grounding plane layer; and the PFL is formed in a PFL-pattem configuration that approximately matches the DSS-pattem configuration.

11. The display assembly of claim 9 or claim 10, wherein the display, the PFL, and the UDFPS are laminated together, effective to form a display module.

12. The display assembly of any of claims 9-11, wherein: the OFM comprises a thin-film micro-lens, ML, array; and the DSS is integrated with the ML array and configured to be attached to the PFL, the PFL disposed between the ML array and the display.

13. The display assembly of any of claims 9-11, wherein: the OFM comprises a collimator; and the DSS is attached to the collimator and configured to be attached to the PFL, the PFL disposed between the collimator and the display.

14. An electronic device, comprising: a display assembly according to any one of claims 8 to 13; and an imaging processor configured to: obtain, from the FPS, the images of the objects proximate the user-facing side of the display; convert the images to image data; determine, based on the image data, a static pattern within the image, the static pattern caused by the DSS; and remove the static pattern from the image.