System with ultrasound sensor

Abstract

A user classification system is provided. The system includes a user device and a sensor for producing a sensor signal. The sensor produces a sensor signal and comprises a controller. The controller can provide drive signals to be transmitted by the sensor as ultrasonic pulses and receive and process signals recorded by the sensor. The signals recorded by the sensor can include one or more recorded reflections of the ultrasonic pulses transmitted by the sensor. The system classifies a user of the system based on the sensor signal.

Description

[0001] Docket No. ORC-012-PCT

[0002] SYSTEM WITH ULTRASOUND SENSOR

[0003] RELATED APPLICATIONS

[0004]

[0001] This application claims the benefit of United States Provisional Patent Application Serial No. 63 / 735,629 (Docket No. ORC-012-PR1), titled “System with Ultrasound Sensor”, filed December 18, 2024, the content of which is incorporated herein by reference in its entirety for all purposes.

[0005]

[0002] This application is related to United States Provisional Application Serial No. 63 / 140,647 (Docket No. ORC-003-PR), titled “Ultrasound Signal-processing System and Associated Methods”, filed January 22, 2021, the content of which is incorporated by reference in its entirety for all purposes.

[0006]

[0003] This application is related to United States Provisional Application Serial No. 63 / 174,516 (Docket No. ORC-004-PR), titled “Multi-platen Ultrasound Fingerprint Sensors and Associated Methods”, filed April 13, 2021, the content of which is incorporated by reference in its entirety for all purposes.

[0007]

[0004] This application is related to United States Provisional Application Serial No. 63 / 189,567 (Docket No. ORC-005-PR1), titled “System Including User Classification”, filed May 17, 2021, the content of which is incorporated by reference in its entirety for all purposes.

[0008]

[0005] This application is related to United States Provisional Application Serial No. 63 / 242,657 (Docket No. ORC-005-PR2), titled “System Including User Classification”, filed September 10, 2021, the content of which is incorporated by reference in its entirety for all purposes.

[0009]

[0006] This application is related to International PCT Patent Application Serial No. PCT / US22 / 013299 (Docket No. ORC-005-PCT), titled “System with Ultrasound Sensor” filed January 21, 2022, WIPO Publication No. WO 2022 / 159692, published July 28, 2022, the content of which is incorporated by reference in its entirety for all purposes.

[0010]

[0007] This application is related to United States Patent Application Serial No. 18 / 272,965 (Docket No. ORC-005-US), titled “System with Ultrasound Sensor” filed July 18, 2023, US Patent No. 12,353,531, issued July 8, 2025, the content of which is incorporated by reference in its entirety for all purposes. Docket No. ORC-012-PCT

[0011]

[0008] This application is related to United States Continuation Application Serial No. 19 / 233,513 (Docket No. ORC-005-US-CON1), titled “Systems with Ultrasound Sensor”, filed June 10, 2025, US Publication No. , published > , the content of which is incorporated by reference in its entirety for all purposes.

[0012]

[0009] This application is related to United States Provisional Patent Application Serial No. 63 / 451,368 (Docket No. ORC-011-PR1), titled “System with Ultrasound Sensor”, filed March 10, 2023, the content of which is incorporated herein by reference in its entirety for all purposes.

[0013]

[0010] This application is related to United States Provisional Patent Application Serial No. 63 / 605,732 (Docket No. ORC-011-PR2), titled “System with Ultrasound Sensor”, filed December 4, 2023, the content of which is incorporated herein by reference in its entirety for all purposes.

[0014]

[0011] This application is related to International PCT Patent Application Serial No. PCT / US24 / 019359, (Docket No. ORC-011 -PCT), titled “System with Ultrasound Sensor”, filed March 11, 2024, WIPO Publication No. WO 2024 / 191896, published September 19, 2024, the content of which is incorporated by reference in its entirety for all purposes.

[0015]

[0012] This application is related to United States National Stage Application Serial No. 19 / 161,833 (Docket No. ORC-011 -US), titled “Systems with Ultrasound Sensor”, filed September 3, 2025, US Publication No. , published > , the content of which is incorporated by reference in its entirety for all purposes.

[0016] FIELD OF INVENTIVE CONCEPTS

[0017]

[0013] The embodiments disclosed herein relate generally to systems which include one or more ultrasound sensors, such as to receive commands from a user or to identify or assess a condition of a user.

[0018] BACKGROUND

[0019]

[0014] Numerous commercial devices include a sensor for collecting user information.

[0020] These systems can include a user identification function, such as a function that identifies a user via fingerprint or face recognition. There is a need for improved systems, devices, and methods for classifying a user of the system. Docket No. ORC-012-PCT

[0021] SUMMARY

[0022]

[0015] According to an aspect of the present inventive concepts, a user classification system comprises a sensor configured to produce a sensor signal and a user device. The sensor comprises a controller configured to: provide drive signals to be transmitted by the sensor as ultrasonic pulses; and receive and process signals recorded by the sensor. The signals recorded by the sensor comprise one or more recorded reflections of the ultrasonic pulses transmitted by the sensor. The system is configured to classify a user of the user device based on the sensor signal.

[0023]

[0016] In some embodiments, the system comprises electronic hardware, and the electronic hardware is configured to perform IQ sampling.

[0024]

[0017] In some embodiments, the system is configured to operate at an operating frequency, and the operating frequency is determined based on a sweep of the frequency range.

[0025]

[0018] In some embodiments, the sensor is configured based on a set of operating parameters, and a sensor calibration procedure is performed to determine the set of operating parameters.

[0026]

[0019] In some embodiments, the system is configured to perform IQ averaging. The IQ averaging can be configured to increase SNR without increasing scan time.

[0027]

[0020] In some embodiments, the sensor comprises an imaging resolution and a set of ultrasound transducers with a physical pitch that is less than the imaging resolution.

[0028]

[0021] In some embodiments, the system is configured to detect the presence of a finger of the user based on a signal amplitude and phase of a signal produced by the sensor.

[0029]

[0022] In some embodiments, the system is configured to perform image reconstruction using geometric focusing.

[0030]

[0023] In some embodiments, the system is configured to perform image reconstruction using a perturbation method. The perturbation method can comprise a phase perturbation method, an amplitude perturbation method, or both.

[0031]

[0024] The technology described herein, along with the attributes and attendant advantages thereof, will best be appreciated and understood in view of the following detailed description taken in conjunction with the accompanying drawings in which representative embodiments are described by way of example.

[0032] INCORPORATION BY REFERENCE Docket No. ORC-012-PCT

[0033]

[0025] All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. The content of all publications, patents, and patent applications mentioned in this specification are herein incorporated by reference in their entirety. It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part of the common general knowledge in the art in any country.

[0034] BRIEF DESCRIPTION OF THE DRAWINGS

[0035]

[0026] FIG. 1 illustrates a block diagram system for performing a function and classifying a user of the system, consistent with the present inventive concepts.

[0036]

[0027] FIG. l is a perspective view of an ultrasound sensor that combines an ultrasound transducer array with a platen, consistent with the present inventive concepts.

[0037]

[0028] FIG. 3 is a cut-away side view of the ultrasound sensor of FIG. 2, consistent with the present inventive concepts.

[0038]

[0029] FIG. 4 shows a column electrode emitting an ultrasound pulse into the platen of FIGS. 2 and 3, consistent with the present inventive concepts.

[0039]

[0030] FIG. 5 shows a row electrode sensing echoes generated when the ultrasound pulse of FIG. 4 reflects off a top surface of the platen of FIGS. 2 and 3, consistent with the present inventive concepts.

[0040]

[0031] FIG. 6 shows a waveform recorded from a row electrode during emission and sensing of one pixel element of the ultrasound sensor of FIGS. 2 through 5, consistent with the present inventive concepts.

[0041]

[0032] FIG. 7 illustrates a time shift between a baseline sub-waveform and a signal subwaveform, in embodiments, consistent with the present inventive concepts.

[0042]

[0033] FIG. 8 is a block diagram of a finger sensor system that uses the ultrasound sensor array of FIGS. 2 through 5 to image a finger based on time shifts, consistent with the present inventive concepts.

[0043]

[0034] FIG. 9 compares a time-shift image of a fingerprint with a conventional amplitudeshift image of the same fingerprint, consistent with the present inventive concepts.

[0044]

[0035] FIG. 10 shows a fingerprint image generated using only signal arrival times of signal waveforms, consistent with the present inventive concepts. Docket No. ORC-012-PCT

[0045]

[0036] FIG. 11 is a flow chart of an ultrasound signal-processing method that uses baseline time compensation, in embodiments, consistent with the present inventive concepts.

[0046]

[0037] FIG. 12 is a flow chart of a method for processing a waveform to identify an arrival time of an echo, in embodiments, consistent with the present inventive concepts.

[0047]

[0038] FIG. 13 is a flow chart of a method for processing a waveform to identify an arrival time of an echo, in embodiments, consistent with the present inventive concepts.

[0048]

[0039] FIG. 14 illustrates a method for processing signal and baseline waveforms to identify a time shift, consistent with the present inventive concepts.

[0049]

[0040] FIG. 15 illustrates a method for processing a waveform to identify an arrival time of an echo, consistent with the present inventive concepts.

[0050]

[0041] FIG. 16 is a flow chart of an ultrasound signal-processing method that generates a time-shift image without baseline waveforms, in embodiments, consistent with the present inventive concepts.

[0051]

[0042] FIG. 17 is a flow chart of an object detection method that does not use baseline waveforms, consistent with the present inventive concepts.

[0052]

[0043] FIG. 18 is a flow chart of an object detection method that uses baseline waveforms, consistent with the present inventive concepts.

[0053]

[0044] FIG. 19 is a block diagram of an ultrasound signal-processing system with which the present method embodiments may be implemented, in embodiments, consistent with the present inventive concepts.

[0054]

[0045] FIG. 20 is a perspective view of a multi-platen ultrasound fingerprint sensor having a first platen and a second platen with different round-trip propagation times, consistent with the present inventive concepts.

[0055]

[0046] FIG. 21 is a side cross-sectional view of the multi-platen ultrasound fingerprint sensor of FIG. 20, consistent with the present inventive concepts.

[0056]

[0047] FIG. 22 shows the multi-platen ultrasound fingerprint sensor of FIGS. 20 and 21 being electrically driven to simultaneously emit a first ultrasound pulse into the first platen and a second ultrasound pulse into the second platen, consistent with the present inventive concepts.

[0057]

[0048] FIG. 23 shows the multi-platen ultrasound fingerprint sensor of FIG. 22 sensing a first echo and a second echo, consistent with the present inventive concepts.

[0058]

[0049] FIG. 24 is a side cross-sectional view of a multi-platen ultrasound fingerprint sensor that is similar to the multi-platen ultrasound fingerprint sensor of FIGS. 20 through 23 except that it has coplanar front faces, consistent with the present inventive concepts. Docket No. ORC-012-PCT

[0059]

[0050] FIG. 25 is a side cross-sectional view of a multi-platen ultrasound fingerprint sensor in which one array of pixel transducers is used with both first and second platens, consistent with the present inventive concepts.

[0060]

[0051] FIGS. 25A-D illustrate various electrical configurations of an ultrasound sensor, consistent with the present inventive concepts.

[0061]

[0052] FIG. 26 is a block diagram of a fingerprint-sensing system that uses a multi-platen ultrasound fingerprint sensor, consistent with the present inventive concepts.

[0062]

[0053] FIG. 27 is a side cross-sectional view of an ultrasound fingerprint sensor with a wedged platen, consistent with the present inventive concepts.

[0063]

[0054] FIG. 28 shows two cross-sectional side views of an anti -reflection coated multi-platen ultrasound fingerprint sensor, consistent with the present inventive concepts.

[0064]

[0055] FIG. 29 is a block diagram of hardware and software portions of a system of the present inventive concepts.

[0065]

[0056] FIGS. 30, 31A-31D are a graph of IQ values, and a set of four images of phantoms that were processed using averaged IQ data, respectively, consistent with the present inventive concepts.

[0066]

[0057] FIGS. 32A and 32B is a graph of ultrasound reflection positions and a graph of an ultrasound signal received by an ultrasound array, respectively, consistent with the present inventive concepts.

[0067]

[0058] FIG. 33 is a schematic view of an ultrasound sensor comprising a physical pitch of ultrasound transducers that is less than the imaging resolution of the sensor, consistent with the present inventive concepts.

[0068]

[0059] FIGS. 34A and 34B are schematic representations of different sets of transmit and receive pairs of an ultrasound transducer, respectively, consistent with the present inventive concepts.

[0069]

[0060] FIGS. 35A-35C are flow charts and graphs of sample IQ data for three methods of finger-on detection (FOD) techniques, consistent with the present inventive concepts.

[0070]

[0061] FIGS. 36A-36D are visual examples of a raw and an optimized phase delay profile, and pre and post processed images, respectively, consistent with the present inventive concepts.

[0071]

[0062] FIGS. 37A-37D are visual representations of various image processing processes, and pre and post processed images, respectively, consistent with the present inventive concepts.

[0072] DETAILED DESCRIPTION OF THE DRAWINGS DocketNo. ORC-012-PCT

[0073]

[0063] Reference will now be made in detail to the present embodiments of the technology, examples of which are illustrated in the accompanying drawings. Similar reference numbers may be used to refer to similar components. However, the description is not intended to limit the present disclosure to particular embodiments, and it should be construed as including various modifications, equivalents, and / or alternatives of the embodiments described herein.

[0064] It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination. For example, it will be appreciated that all features set out in any of the claims (whether independent or dependent) can be combined in any given way.

[0074]

[0065] It is to be understood that at least some of the figures and descriptions of the invention have been simplified to focus on elements that are relevant for a clear understanding of the invention, while eliminating, for purposes of clarity, other elements that those of ordinary skill in the art will appreciate may also comprise a portion of the invention. However, because such elements are well known in the art, and because they do not necessarily facilitate a better understanding of the invention, a description of such elements is not provided herein.

[0075]

[0066] Terms defined in the present disclosure are only used for describing specific embodiments of the present disclosure and are not intended to limit the scope of the present disclosure. Terms provided in singular forms are intended to include plural forms as well, unless the context clearly indicates otherwise. All of the terms used herein, including technical or scientific terms, have the same meanings as those generally understood by an ordinary person skilled in the related art, unless otherwise defined herein. Terms defined in a generally used dictionary should be interpreted as having meanings that are the same as or similar to the contextual meanings of the relevant technology and should not be interpreted as having ideal or exaggerated meanings, unless expressly so defined herein. In some cases, terms defined in the present disclosure should not be interpreted to exclude the embodiments of the present disclosure.

[0076]

[0067] It will be understood that the words "comprising" (and any form of comprising, such as "comprise" and "comprises"), "having" (and any form of having, such as "have" and "has"), "including" (and any form of including, such as "includes" and "include") and / or "containing" (and any form of containing, such as "contains" and "contain") when used herein, specify the presence of stated features, integers, steps, operations, elements, and / or Docket No. ORC-012-PCT components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0077]

[0068] It will be further understood that, although the terms first, second, third, etc. may be used herein to describe various limitations, elements, components, regions, layers and / or sections, these limitations, elements, components, regions, layers and / or sections should not be limited by these terms. These terms are only used to distinguish one limitation, element, component, region, layer or section from another limitation, element, component, region, layer or section. Thus, a first limitation, element, component, region, layer or section discussed below could be termed a second limitation, element, component, region, layer or section without departing from the teachings of the present application.

[0078]

[0069] It will be further understood that when an element is referred to as being "on", "attached", "connected" or "coupled" to another element, it can be directly on or above, or connected or coupled to, the other element, or one or more intervening elements can be present. In contrast, when an element is referred to as being "directly on", "directly attached", "directly connected" or "directly coupled" to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., "between" versus "directly between," "adjacent" versus "directly adjacent," etc.).

[0079]

[0070] As used herein, the terms “operably attached”, “operably connected”, “operatively coupled” and similar terms related to attachment of components shall refer to attachment of two or more components that results in one, two, or more of: electrical attachment; fluid attachment; magnetic attachment; mechanical attachment; optical attachment; sonic attachment; and / or other operable attachment arrangements. The operable attachment of two or more components can facilitate the transmission between the two or more components of: power; signals; electrical energy; fluids or other flowable materials; magnetism; mechanical linkages; light; sound such as ultrasound; and / or other materials and / or components.

[0080]

[0071] It will be further understood that when a first element is referred to as being "in", "on" and / or "within" a second element, the first element can be positioned: within an internal space of the second element, within a portion of the second element (e.g., within a wall of the second element); positioned on an external and / or internal surface of the second element; and combinations of two or more of these.

[0081]

[0072] As used herein, the term “proximate”, when used to describe proximity of a first component or location to a second component or location, is to be taken to include one or more locations near to the second component or location, as well as locations in, on and / or Docket No. ORC-012-PCT within the second component or location. For example, a component positioned proximate an anatomical site (e.g., a target tissue location), shall include components positioned near to the anatomical site, as well as components positioned in, on and / or within the anatomical site.

[0073] Spatially relative terms, such as "beneath," "below," "lower," "above," "upper" and the like may be used to describe an element and / or feature's relationship to another element(s) and / or feature(s) as, for example, illustrated in the figures. It will be further understood that the spatially relative terms are intended to encompass different orientations of the device in use and / or operation in addition to the orientation depicted in the figures. For example, if the device in a figure is turned over, elements described as "below" and / or "beneath" other elements or features would then be oriented "above" the other elements or features. The device can be otherwise oriented (e.g., rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0082]

[0074] The terms “reduce”, “reducing”, “reduction” and the like, where used herein, are to include a reduction in a quantity, including a reduction to zero. Reducing the likelihood of an occurrence shall include prevention of the occurrence. Correspondingly, the terms “prevent”, “preventing”, “prevention” and the like, where used herein, shall include the acts of “reduce”, “reducing”, and “reduction”, respectively.

[0083]

[0075] The term "and / or" where used herein is to be taken as specific disclosure of each of the two specified features or components with or without the other. For example "A and / or B" is to be taken as specific disclosure of each of (i) A, (ii) B and (iii) A and B, just as if each is set out individually herein.

[0084]

[0076] The term “one or more”, where used herein can mean one, two, three, four, five, six, seven, eight, nine, ten, or more, up to any number.

[0085]

[0077] The terms “and combinations thereof’ and “and combinations of these” can each be used herein after a list of items that are to be included singly or collectively. For example, a component, process, and / or other item selected from the group consisting of: A; B; C; and combinations thereof, shall include a set of one or more components that comprise: one, two, three or more of item A; one, two, three or more of item B; and / or one, two, three, or more of item C.

[0086]

[0078] In this specification, unless explicitly stated otherwise, “and” can mean “or”, and “or” can mean “and”. For example, if a feature is described as having A, B, or C, the feature can have A, B, and C, or any combination of A, B, and C. Similarly, if a feature is described as having A, B, and C, the feature can have only one or two of A, B, or C. Docket No. ORC-012-PCT

[0087]

[0079] The expression “configured (or set) to” used in the present disclosure may be used interchangeably with, for example, the expressions “suitable for”, “having the capacity to”, “designed to”, “adapted to”, “made to” and “capable of’ according to a situation. The expression “configured (or set) to” does not mean only “specifically designed to” in hardware. Alternatively, in some situations, the expression “a device configured to” may mean that the device “can” operate together with another device or component.

[0088]

[0080] As used herein, the term “threshold” refers to a maximum level, a minimum level, and / or range of values correlating to a desired or undesired state. In some embodiments, a system parameter is maintained above a minimum threshold, below a maximum threshold, within a threshold range of values, and / or outside a threshold range of values, such as to cause a desired effect (e.g., a successful function is performed as intended) and / or to prevent or otherwise reduce (hereinafter “prevent”) an undesired event (e.g., performance of a function by an undesired or impaired user). In some embodiments, a system parameter is maintained above a first threshold and below a second threshold. In some embodiments, a threshold value is determined to include a safety margin, such as to account for user variability, system variability, tolerances, and the like. As used herein, “exceeding a threshold” relates to a parameter going above a maximum threshold, below a minimum threshold, within a range of threshold values and / or outside of a range of threshold values.

[0081] As described herein, “room pressure” shall mean pressure of the environment surrounding the systems and devices of the present inventive concepts. “Positive pressure” includes pressure above room pressure or simply a pressure that is greater than another pressure, such as a positive differential pressure across a fluid pathway component such as a valve. “Negative pressure” includes pressure below room pressure or a pressure that is less than another pressure, such as a negative differential pressure across a fluid component pathway such as a valve. Negative pressure can include a vacuum but does not imply a pressure below a vacuum. As used herein, the term “vacuum” can be used to refer to a full or partial vacuum, or any negative pressure as described hereinabove.

[0089]

[0082] The term “diameter” where used herein to describe a non-circular geometry is to be taken as the diameter of a hypothetical circle approximating the geometry being described. For example, when describing a cross section, such as the cross section of a component, the term “diameter” shall be taken to represent the diameter of a hypothetical circle with the same cross-sectional area as the cross section of the component being described. Docket No. ORC-012-PCT

[0090]

[0083] The terms “major axis” and “minor axis” of a component where used herein are the length and diameter, respectively, of the smallest volume hypothetical cylinder which can completely surround the component.

[0091]

[0084] As used herein, the term “fluid” can refer to a liquid, gas, gel, or any flowable material, such as a material which can be propelled through a lumen and / or opening.

[0085] As used herein, the term “material” can refer to a single material, or a combination of two, three, four, or more materials.

[0092]

[0086] As used herein, the term “transducer” is to be taken to include any component or combination of components that receives energy or any input and produces an output. In some configurations, a transducer converts an electrical signal into any output, such as: light (e.g., a transducer comprising a light emitting diode or light bulb), sound (e.g., a transducer comprising one or more piezoelectric transducers and / or capacitive micromachined ultrasound transducers (CMUTs) configured to deliver and / or receive ultrasound energy); pressure (e.g., an applied pressure or force); heat energy; cryogenic energy; chemical energy; mechanical energy (e.g., a transducer comprising a motor or a solenoid); magnetic energy; and / or a different electrical signal (e.g., different than the input signal to the transducer). Alternatively or additionally, a transducer can convert a physical quantity (e.g., variations in a physical quantity) into an electrical signal. Alternatively or additionally, a transducer can comprise a mechanism, such as: a valve; a grasping element; an anchoring mechanism; an electrically-activated mechanism; a mechanically-activated mechanism; and / or a thermally activated mechanism.

[0093]

[0087] As used herein, the term “functional element” is to be taken to include one or more elements constructed and arranged to perform a function. A functional element can comprise one or more sensors and / or one or more transducers. A functional element (e.g., comprising one or more sensors) can be configured to record one or more parameters. In some embodiments, a functional element is configured to perform a function. A “functional assembly” can comprise an assembly constructed and arranged to perform a function. Alternatively or additionally, a functional assembly can be configured to record one or more parameters, such as a user parameter; a user environment parameter; and / or a system parameter. A functional assembly can comprise one or more functional elements.

[0094]

[0088] As used herein, the term “system parameter” comprises one or more parameters of the system of the present inventive concepts.

[0095]

[0089] As used herein, the term “user parameter”, or “operator parameter”, comprises one or more parameters associated with a user (also referred to as an “operator”) of the system of Docket No. ORC-012-PCT the present inventive concepts. A user parameter can comprise a user physiologic parameter, such as a physiologic parameter selected from the group consisting of: temperature (e.g., tissue temperature); pressure such as blood pressure or other body fluid pressure; pH; a blood gas parameter; blood glucose level; hormone level; heart rate; respiration rate; and combinations of these. Alternatively or additionally, a user parameter can comprise a user environment parameter, such as an environment parameter selected from the group consisting of: user geographic location; temperature; pressure; humidity level; light level; time of day; and combinations of these.

[0096]

[0090] As used herein, the term “transmitting a signal” and its derivatives shall refer to the transmission of power and / or data between two or more components, in any direction.

[0097]

[0091] As used herein, the term “conduit” or “conduits” can refer to an elongate component that can include one or more flexible and / or non-flexible filaments selected from the group consisting of: one, two or more wires or other electrical conductors (e.g., including an outer insulator); one, two or more wave guides; one, two, or more hollow tubes, such as hydraulic, pneumatic, and / or other fluid delivery tubes; one or more optical fibers; one two or more control cables and / or other mechanical linkages; one, two or more flex circuits; and combinations of these. A conduit can include a tube including multiple conduits positioned within the tube. A conduit can be configured to electrically, fluidically, sonically, optically, mechanically, and / or otherwise operably connect one component to another component.

[0098]

[0092] As used herein, an “ultrasound transducer” (also referred to as “ultrasound element”) can refer to one or more components configured to transmit ultrasound energy (e.g., based on a delivered electrical signal) and / or one or more components configured to receive ultrasound energy (e.g., and convert it to an electrical signal). An ultrasound transducer can comprise a set of one or more ultrasound transducers, such as a ID or 2D array of ultrasound transducers. An ultrasound transducer can refer to: a set of one or more piezoelectric transducers (also referred to as “piezo” transducers or elements); a set of one or more capacitive micromachine ultrasound transducers (CMUTs), or a set of one or more of both.

[0099]

[0093] As used herein, an “optical transducer” (also referred to as “optical element”) can refer to one or more components configured to transmit light (e.g., a diode such as a laser diode) and / or one or more components configured to receive and / or facilitate the travel of light (e.g., a lens, prism, optical fiber, and the like).

[0100]

[0094] The systems, devices, and methods of the present inventive concepts include one, two, or more sensors (e.g., ultrasound-based sensors, capacitive sensors, and / or light-based Docket No. ORC-012-PCT sensors) that are configured to collect data of a user. The data collected (e.g., fingerprint data, pulse oximetry data, and / or other physiologic and anatomic data) can be used to verify that a proper user is present for use of a device or system.

[0101]

[0095] Referring now to FIG. 1, a schematic view of a system for performing a function for a user is illustrated, consistent with the present inventive concepts. System 10 can be configured to perform a function, such as to perform one or more functions associated with: a smart phone or other cellular phone (“smart phone” or “cell phone” herein), a watch such as a smart watch, a gaming device, a computer such as a tablet or laptop computer, a vehicle, a piece of equipment, a storage device such as a secure storage device, and / or other user- accessible device or system. System 10 can be configured to perform an identification routine (e.g., to determine the identity of one or more users), and / or a confirmation routine (e.g., to confirm the identity of one or more users). System 10 can be configured to perform a classification routine, such as to classify one or more users of system 10, such as a classification comprising identifying a user (e.g., determining and / or confirming the identity of a user), and / or characterizing a health or other condition of a user (e.g., confirming and / or identifying a health or other condition of a user). A user identification and / or confirmation routine (either or both referred to as “identification routine” or “confirmation routine” herein), can be performed in various ways, such as via a fingerprint, via an image of the user’s face, via a recording of the person’s voice, via recorded life signs (e.g., current physiologic parameters) of a user, and / or via a combination of two or more of these. In some embodiments, two, three or more forms of data (e.g., fingerprint, facial image, voice recording, and / or physiologic data) are used to establish the identity and / or provide other status information (e.g., current health status) of a user. In some embodiments, physiologic data of a user (e.g., physiologic data such as: pulse oximetry data; blood glucose data; EEG, LFP, neuronal firing patterns, and / or other brain data; heart rate data; respiration data; perspiration data; and / or blood gas data) can be characterized (e.g., patterns recognized) in a classification routine, such as to identify, confirm, and / or otherwise characterize a health condition of the user. Alternatively or additionally, physiologic data collected by system 10 can be used to identify and / or confirm (“identify” or “confirm” herein) a user in a similar arrangement to that performed using fingerprint, facial images, and / or voice recordings.

[0102]

[0096] System 10 includes one, two, or more sensors, sensor 100 shown. Sensor 100 can comprise one or more sensors that are positioned proximate (e.g., within and / or on) another component of system 10. Sensor 100 can comprise an ultrasound-based sensor, such as a Docket No. ORC-012-PCT piezo-based, CMUT-based, and / or other ultrasound-based sensor such as is described herein. In some embodiments, sensor 100 comprises one, two, or more sensors selected from the group consisting of: ultrasound-based sensor; capacitive touch sensor; optical sensor; electrical sensor; magnetic sensor; force sensor; pressure sensor; strain gauge; accelerometer; physiologic sensor; microphone (e.g., for recording the voice of a user); camera (e.g., for recording the face of a user); and combinations of these. Sensor 100 can comprise a “detection area” which includes one or more 2D or 3D surfaces from which user input can be recorded, such as user input including: contact of a finger or other body portion of a user (e.g., to select an icon, type on a keyboard, and / or otherwise enter data into a user interface); an image of the user’s tissue such as an image of a fingerprint or other tissue surface; temperature of tissue of a user; pulse oximetry, blood pressure, electrocardiogram, and / or other physiologic information of a user; and combinations of these. In some embodiments, sensor 100 comprises an ultrasound-based sensor.

[0103]

[0097] System 10 can include one, two, or more cell phones such as smart phones, watches such as smart watches, gaming devices, tablets, computers, user protection devices, vehicles or other transportation devices, banking and / or other transaction devices, medical devices, and / or other user devices, user device 500 shown. In some embodiments, sensor 100 is integral to user device 500. Each user device 500 can comprise a user interface, user interface 550 shown. User interface 550 can comprise one or more user input components and / or user output components, such as one or more components selected from the group consisting of: display; touchscreen display; a light such as an LED; switch; button; knob; a keypad such as a membrane keypad; keyboard; lever; joystick; speaker; microphone; vibrational transducer and / or other haptic transducer; a capacitive sensor or switch; an ultrasound-based sensor or switch; and combinations of these. Each user device 500 can comprise a communicator, such as communicator 570 shown, which can be configured to transfer information between user device 500 and another component of system 10, such as to transfer information between the components. Communicator 570 can comprise a wired communication assembly, such as when communicator 570 comprises a cable configured to operably (e.g., electrically) attach user device 500 to another component of system 10. Alternatively or additionally, communicator 570 can comprise a wireless communication module, such as an NFC and / or Bluetooth module configured to transfer information between user device 500 and another component of system 10. Each user device 500 can comprise one or more assemblies, functional assembly 580 shown, which can be configured to provide an output and / or otherwise perform a function of user device 500. Functional Docket No. ORC-012-PCT assembly 580 can comprise one or more assemblies which provide a function selected from the group consisting of: a cell phone function such as a communication function and / or a smartphone function; a transportation function; a storage function; a gaming function; a medical device function (e.g., a therapeutic and / or diagnostic function); a testing function such as a laboratory testing function; a manipulation function (e.g., an excavation function); a recreational function; a storage function such as a secure storage function; a data processing function; a computer function; a financial transaction function; and combinations of these.

[0098] In some embodiments, user interface 550 includes sensor 100, such as when user interface 550 comprises a multi-layer construction, and all or at least a portion of sensor 100 is integrated into one or more layers of interface 550. In these embodiments, user interface 550 can comprise a touch screen, and the integrated sensor 100 can comprise an ultrasoundbased sensor (e.g., as described in reference to FIGS. 2 through 28 and otherwise herein). In some embodiments, user interface 550 includes such an ultrasound-based sensor, but interface 550 is void of either or both of a capacitance-based sensor and / or an optical sensor (e.g., the ultrasound-based sensor 100 is configured to provide all user touch-based input to the user interface 550 and associated device 500). Alternatively, user interface 550 can comprise a sensor 100 that includes an ultrasound-based sensor, as well as either or both of a capacitive sensor and an optical sensor.

[0104]

[0099] User interface 550 can comprise an integrated sensor 100 that can be constructed and arranged to receive user input from a majority of the “surface” of user interface 550 (e.g., the user-accessible surface portion of interface 550), such as when the detection area of sensor 100 (e.g., an ultrasound-based sensor as described herein) is at least 51%, at least 70%, at least 80%, and / or at least 90% of the visualizable portion of user interface 550. In some embodiments, the detection area of sensor 100 (e.g., an ultrasound-based sensor as described herein) has an area of at least 10,000mm2, 40,000mm2, and / or 1,000,000mm2and / or has a major axis of at least 20cm, 40cm, and / or 80cm.

[0105]

[0100] In some embodiments, sensor 100 can be located proximate and oriented toward an outer portion of device 500, for example a housing portion (e.g., housing 510 described herein), such that sensor 100 can image a fingerprint of a finger that is placed on the outer portion of device 500 proximate sensor 100. For example, sensor 100 can be located along an edge of device 500, and / or proximate a button or other user-control portion of a housing of device 500. In some embodiments, a sensor 100 comprising multiple similar and / or dissimilar sensors 100 can be located along one or more edges of device 500 at one or more Docket No. ORC-012-PCT locations, such as to record a fingerprint of multiple fingers of a user (e.g., capture multiple fingerprints simultaneously and / or sequentially), as described herein.

[0106]

[0101] As described herein, user interface 550 and / or sensor 100 (e.g., a sensor 100 that is integral to interface 550 as described herein) can comprise a first sensor that is configured to operate at a first power level, and a second sensor that operates at a second power level that is greater than the first power level. In these embodiments, system 10 (e.g., controller 200 described herein) can be configured to operate in a lower power mode in which power is provided to the first sensor but not the second sensor (e.g., the second sensor is off or in a standby state). Contact and / or other activation by a user with the first sensor causes system 10 to provide power to the second sensor (e.g., to turn on or otherwise make the second sensor active). The second sensor can comprise an ultrasound-based sensor comprising multiple pixel elements as described herein, such as a sufficient number of pixel elements to identify one or more users via one or more fingerprints of the user. The first sensor can comprise a mechanical switch, a pressure sensor, a capacitive sensor, a low-resolution ultrasound-based pixel transducer array, and / or other low power sensor. In some embodiments, the first sensor and the second sensor comprise a sensor 100a and 100b, respectively, that are integrated into a user interface 550 of a device 500 (e.g., a cell phone, tablet, or other battery-operated device). Similar to sensor 100a, second sensor 100b can be constructed and arranged to receive user input from a majority of the “surface” of user interface 550 (e.g., the user-accessible surface portion of interface 550), such as when the detection area of sensor 100b (e.g., an ultrasound-based sensor as described herein) is at least 51%, at least 70%, at least 80%, and / or at least 90% of the visualizable portion of user interface 550. In some embodiments, the detection area of sensor 100b (e.g., an ultrasoundbased sensor as described herein) has an area of at least 10,000mm2, 40,000mm2, and / or 1,000,000mm2and / or has a major axis of at least 20cm, 40cm, and / or 80cm.

[0107]

[0102] System 10 can include one or more control modules, controller 200 shown, which can be configured to transmit signals to, and / or receive signals from, sensor 100. Alternatively or additionally, controller 200 can be configured to interface or otherwise operatively connect two or more components of system 10 to each other. Controller 200 can comprise one or more electronic elements, electronic assemblies, and / or other electronic components, such as components selected from the group consisting of memory storage components; analog-to-digital converters; rectification circuitry; state machines; microprocessors; microcontrollers; filters and other signal conditioners; sensor interface circuitry; transducer interface circuitry; and combinations thereof. In some embodiments, Docket No. ORC-012-PCT controller 200 comprises a memory storage component that includes instructions, such as instructions used by controller 200 to perform an algorithm, such as algorithm 60 described herein. In some embodiments, controller 200 is integral to a user device 500 (e.g., a user device 500 that comprises a sensor 100). Controller 200 can be configured to electrically, mechanically, acoustically, fluidically, optically, and / or otherwise operably connect two components of system 10 to each other, such as to operably connect sensor 100 to another component of system 10, such as to connect sensor 100 to user device 500 as described herein. Controller 200 can comprise various electronic components and circuitry that are configured to operably interface with one or more components of system 10, and / or to facilitate operably interfacing any component of system 10 with another component of system 10. In some embodiments, controller 200 comprises one or more application specific integrated circuits (ASICs), such as one, two, or more ASICs configured to transmit signals to and / or receive signals from one or more pixel elements of an ultrasound-based sensor 100 as described herein. In some embodiments, a single ASIC is configured to drive at least 250 transmit lines and at least 250 receive lines, as described herein. In other embodiments, multiple ASICs are configured to drive (e.g., in a parallel arrangement) at least 500, at least 1000, and / or at least 5000 pairs of transmit and receive lines.

[0108]

[0103] System 10 can comprise FOB 600 shown. FOB 600 can comprise one, two, or more fobs and / or other handheld electronic or other devices (“fobs” herein), such as a device configured to fit in a user’s pocket, purse, wallet, and / or other user location such that FOB 600 can easily be carried by the user in daily life activities. In some embodiments, FOB 600 comprises sensor 100 (e.g., and also controller 200). For example, FOB 600 can comprise at least an ultrasound-based sensor, as described herein, such as to identify the fingerprint of a user. FOB 600 can comprise user interface 650 shown. In some embodiments, user interface 650 is of similar construction and arrangement as user interface 550 described herein. FOB 600 can comprise an assembly, communicator 670 shown, which can be configured to transfer information between FOB 600 and another component of system 10, such as to transfer information between FOB 600 and user device 500 (e.g., when FOB 600 comprises sensor 100 and user information recorded by sensor 100 is transferred to user device 500 via communicator 670). Communicator 670 can comprise a wired communication assembly, such as when communicator 670 comprises a cable configured to operably (e.g., electrically) attach FOB 600 to device 500 and / or another component of system 10. Alternatively or additionally, communicator 670 can comprise a wireless communication module, such as an NFC and / or Bluetooth module that is configured to Docket No. ORC-012-PCT transfer information between FOB 600 and communicator 570 of user device 500 and / or a similar wireless module of another system 10 component.

[0109]

[0104] System 10 can comprise one, two, or more accessory devices, accessory device 700 shown. Accessory device 700 can comprise one or more devices that function in cooperation with another system 10 component. In some embodiments, accessory device 700 comprises all or a portion of sensor 100 and / or all or a portion of controller 200.

[0110]

[0105] System 10 can include one or more algorithms, algorithm 60 shown. Algorithm 60 can comprise a machine learning, neural network, and / or other artificial intelligence algorithm (“Al algorithm” herein).

[0111]

[0106] Algorithm 60 can comprise an algorithm configured to detect an attempt at “spoofing” of a user confirmation routine performed by system 10.

[0112]

[0107] Algorithm 60 can comprise an algorithm configured to analyze life signs of a user (e.g., pulse oximetry, blood glucose, heart rate, blood pressure, respiration, EKG, EEG, LFP, and / or neuronal firing), such as to identify and / or characterize a user via the analysis (e.g., an analysis of a single physiologic parameter or multiple physiologic parameters in combination).

[0113]

[0108] Algorithm 60 can comprise an algorithm that analyzes fingerprint data (e.g., as recorded by sensor 100) to identify a user. In some embodiments, algorithm 60 comprises an algorithm that analyzes fingerprint data and another form of user data to identify a user, such as other data including: facial images (e.g., images produced by a camera of system 10); voice recordings (e.g., recordings produced by a microphone of system 10); physiologic data (also referred to as life sign data herein); and combinations of these. In these embodiments, algorithm 60 can comprise a weighting factor and / or a bias that preferentially selects one form of user identification data versus another.

[0114]

[0109] System 10 can comprise one, two, or more computer networks, network 800 shown, such as a cellular and / or other wireless network, LAN, WAN, VPN, the Internet, and / or other computer network. In some embodiments, user information and / or other information collected and / or produced by a system 10 component is transferred via network 800 to one or more central locations, such as when this information comprises information related to use of system 10 by multiple users (e.g., users of multiples of various system 10 components) that is analyzed by system 10, such as by an algorithm 60 of system 10 as described herein. Such analysis of information from multiple users of system 10 can be used to improve the performance of system 10 with one or more users of system 10. In some embodiments, Docket No. ORC-012-PCT algorithm 60 comprises an Al algorithm that analyzes information from multiple users as collected via network 800.

[0115]

[0110] System 10 can comprise one, two, or more functional elements, such as functional element 199 of sensor 100, functional element 599 of user device 500, functional element 699 of FOB 600, and / or functional element 999, each as shown. Each functional element 199, 599, 699, and / or 999 can comprise one, two, or more functional elements, such as one or more sensors and / or one or more transducers, such as are described herein.

[0116]

[0111] Sensor 100 can comprise one, two or more sensors 100. Sensor 100 can comprise multiple sensors that are similar, and / or multiple sensors that are dissimilar (e.g., two or more different fingerprint sensors). Sensor 100 can comprise one or more sensors 100 that are integral to (e.g., positioned on and / or within, and operably attached to) another component of system 10 (e.g., integral to user device 500), as well as one or more sensors 100 that are integral to a different component of system 10 (e.g., integral to FOB 600, accessory device 700, and / or a different user device 500).

[0117]

[0112] As described herein, sensor 100 can comprise at least an ultrasound-based sensor, such as a sensor comprising an array 150 including one, two, or more ultrasound transducers (e.g., piezo and / or CMUT elements) configured to transmit, receive, or both transmit and receive, ultrasound energy. In some embodiments, controller 200 is configured to drive array 150 (e.g., a ID or 2D array of ultrasound transducers) at a frequency of at least 1MHz, 5MHz, 10MHz, 25MHz, or 50MHz, such as when controller 200 drives array 150 at a frequency between 50MHz and 500MHz, or between 12.5MHz and 100MHz. In some embodiments, controller 200 is configured to drive this ultrasound-based array 150 at a frequency of no more than 500MHz, or no more than 750MHz. In some embodiments, sensor 100 comprises a piezo-on-glass arrangement, and controller 200 is configured to drive array 150 at a frequency of at least 50MHz, and / or no more than 500MHz. Alternatively, or additionally, sensor 100 can comprise a piezo-on-plastic (e.g., PVC) arrangement, and controller 200 can be configured to drive array 150 at a frequency of at least 12.5MHz, and / or no more than 100MHz. In some embodiments, controller 200 is configured to drive array 150 at a frequency of less than 50MHz, such as less than 40MHz, and / or at least 10MHz. Sensor 100 can be configured in a phase and / or delay measurement arrangement (e.g., and operate without a frequency limit). In some embodiments, sensor 100 is configured to perform transmit and receive beamforming of ultrasound transmissions.

[0118]

[0113] In some embodiments, sensor 100 is configured to function, and have significant repeatability, specificity, or both, when operating in wet and / or “underwater” (e.g., Docket No. ORC-012-PCT submersed in fluid) conditions. System 10 and sensor 100 can be configured to operate under a wide variety of wet conditions. In some embodiments, sensor 100 is configured to have improved performance during wet or other conditions, such as when sensor 100 comprises an enhanced fingerprint detector that transmits ultrasound signals deeper into a finger when the finger and / or the surface contacted by the finger is wet (e.g., when system 10 is configured to perform high-value banking transaction confirmations and / or other high security scans). For operation in wet conditions, high-importance modes of confirmation, and / or other conditions, sensor 100 can comprise a mass-loaded ultrasound transducer, such as a Langevin transducer. Sensor 100 can drive the center frequency of ultrasound delivery at a low level, such as a level low enough to travel through (e.g., pass through) patient tissue.

[0119]

[0114] In some embodiments, sensor 100 comprises an ultrasound array (e.g., a piezoelectric ultrasound array) including an arrangement of row electrodes and column electrodes as described herein. The row and column electrodes can comprise two sets of conductors (or “wires” or “traces”) that are relatively orthogonal to each other, such as is described in United States Patent Number 9,953,205. Alternatively, the two sets of conductors can be aligned at an angle of less than 90°, such as at an angle of no more than 89°, an angle between 1° and 89°, and / or at an angle of at least 45°. In some embodiments, the row and column electrodes have a uniform width along their length. Alternatively or additionally, one or more of these electrodes of sensor 100 can comprise a non-uniform width, such as when the conductors narrow between the locations of the ultrasound transducers (e.g., a narrowing that allows more light to travel through the arrangement of conductors forming the set of row electrodes and column electrodes). In these non-uniform arrangements, the thickness of the conductors can be increased to achieve a similar resistance to that which would be present in a uniform arrangement (e.g., an increase in conductor thickness that can correlate to a change in the backing of the piezo transducer and / or the drive frequency of the transducer).

[0120]

[0115] In some embodiments, sensor 100 comprises an ultrasound array (e.g., a piezoelectric ultrasound array) that provides a minimum resolution of a user’s fingerprint (and / or other tissue surface of the user such as the palm or other tissue surface), such as a resolution of at least 100 pixels per inch, at least 200 pixels per inch (PPI), at least 350 PPI, at least 500 PPI, and / or at least 1000 PPI. In some embodiments, system 10 is configured to provide a resolution of at least 200pm, such as a resolution of at least 200pm, 75pm, 50pm, 25pm, and / or 10pm of a fingerprint or other image captured by sensor 100. In some embodiments, system 10 is configured to capture a minimum number of pixels of a fingerprint or other Docket No. ORC-012-PCT image captured by sensor 100, such as at least 15,000 pixels, at least 25,000 pixels, at least 35,000 pixels, at least 50,000 pixels, and / or at least 100,000 pixels.

[0121]

[0116] In some embodiments, sensor 100 is configured as a touch sensor (e.g., to detect a tap or other touch by a user). In these embodiments, sensor 100 can be further configured as a fingerprint sensor or other sensor that identifies a particular user.

[0122]

[0117] In some embodiments, sensor 100 comprises an ultrasound-based sensor 100a and a light-based sensor 100b positioned behind sensor 100a such that light delivered and / or received by sensor 100b passes through sensor 100a, such as is described in United States Patent Number 10,691,912.

[0123]

[0118] In some embodiments, sensor 100 comprises at least a light sensor configured to assess the aliveness of a user and / or to assess another physiologic parameter of the user.

[0124]

[0119] In some embodiments, sensor 100 is configured to provide feedback to a user of system 10, such as thermal and / or mechanical feedback as described herein. For example, sensor 100 can comprise an ultrasound-based sensor that is configured to provide thermal (e.g., heating) and / or mechanical (e.g., force or other tactile) feedback to a user. In these embodiments, a user device 500 including both a user interface 550 (e.g., a touchscreen or other display) as well as sensor 100, can be configured to operate in a “dark mode” where communication to the user can be provided via the thermal, mechanical, and / or other haptic feedback, without the need for the user to visualize user interface 550 (e.g., providing the ability to “stay dark” such as in a military or policing operation, and / or when device 500 is in the user’s pocket or other personal hidden storage location). In some embodiments, the form and / or level of feedback changes based on the amount of “battery life” remaining (e.g., the energy remaining in a battery and / or other energy source of system 10, such as an energy source of user device 500), such as when the changes in form and / or level of feedback are determined by algorithm 60.

[0125]

[0120] As described hereinabove, sensor 100 can be configured to provide feedback, instructions, and / or other information (“feedback” herein) to a user of system 10. For example, feedback provided to a user can comprise a vibration, thermal sensation, audio signal (e.g., a beep) and / or other non-textually and / or non-verbally provided feedback that indicates to a user (e.g., via training) that an action is to be taken by the user (e.g., applying a different finger to user interface 550, moving a currently contacting finger to a new location, and / or performing another physical activity). The feedback provided can comprise at least a thermal sensation, such as when sensor 100 causes an increase in temperature of the patient’s finger or other tissue of the patient. For example, sensor 100 can comprise a platen (e.g., a Docket No. ORC-012-PCT glass platen), as described herein, and controller 200 can be configured to provide a drive signal to array 150 of sensor 100 that matches the platen’s resonance frequency, resulting in a power transmission into tissue (e.g., the finger) of the user in contact with sensor 100 that causes a thermal haptic sensation. In some embodiments, controller 200 provides enough power to cause a tissue temperature increase associated with “thermal touch” feedback, such as a tissue temperature increase of at least 0.2°C, such as at least 0.5°C, at least 1.0°C, at least 5.0°C, and / or at least 10.0°C. In some embodiments, controller 200 is configured to cause a tissue temperature increase of no more than 4°C, no more than 10°C, no more than 20°C, and / or no more than 30°C. In these embodiments, the platen can comprise a uniform thickness, such that the platen creates a resonant acoustic cavity. When controller 200 provides a drive signal with a frequency that matches the resonance of this cavity, multiple reflections within the platen can sum in a constructive way while transmitting into the finger. In these embodiments, the drive signal provided by controller 200 can comprise a continuous wave / tone burst signal (e.g., not pulse excitation). The resonant based feedback described above can be configured to provide a mechanical sensation to the user (e.g., as an alternative to, or in addition to thermal feedback, such as by modulating the drive signal, such as at a frequency of 300Hz). In some embodiments, controller 200 is configured to provide a chirp signal that causes an ultrasound-based array 150 to transmit ultrasound waves at different frequencies (e.g., as a way of adjusting the frequency to match the platen resonant frequency). In some embodiments, the mechanical, thermal, and / or other feedback provided by sensor 100 to the user is adjustable and / or calibratable.

[0126]

[0121] In some embodiments, system 10 is configured in a “no-look mode”, such as to provide feedback and / or any information (e.g., text provided in braille) without requiring sight of the user, or visual attention of the user, to user interface 550, user interface 650, and / or other display portion of system 10 (e.g., such as when the user is blind, or user device 500 is in a pocket, purse, or other non-line of sight location relative to the user). In these embodiments, system 10 can be configured to provide thermal, mechanical, and / or other haptic feedback to the user representing various forms of information.

[0127]

[0122] In some embodiments, system 10 is configured in an “enhanced feedback mode”, such as to provide haptic feedback (e.g., thermal or mechanical feedback as described herein) as well as visual feedback. This enhanced feedback mode can be used to improve the experience of using a gaming and / or other application of user device 500. In some embodiments, device 500 is capable of receiving (e.g., downloading) third-party applications, and sensor 100 is configured to provide haptic feedback that is used by these applications. In Docket No. ORC-012-PCT some embodiments, system 10 comprises a calibration function that is configured to adjust the feedback provided to a third-party application.

[0128]

[0123] In some embodiments, sensor 100 comprises multiple sensors 100 (e.g., multiple similar sensors 100) that are arranged in a close-proximity arrangement (e.g., the periphery of each sensor 100 borders the periphery of a neighboring sensor), where these multiple sensors 100 can be collectively configured (e.g., in an interface arrangement) to function as a single sensor 100 (e.g., via electronic “stitching” via controller 200). For example, sensor 100 can comprise: three sensors in a 1 by 3 array; four sensors arranged in a 1 by 4 array, or in a 2 by 2 array; six sensors arranged in a 1 by 6 array, or in a 2 by 3 array; and the like. These multiple sensors of sensor 100 can be constructed and arranged (e.g., attached to a flexible or hinged substrate) to rotate relative to each other (e.g., at least two sensors rotate relative to each other), such as when included in a device configured to flex (e.g., a smart card or other device in which flexibility or at least flexing provides an advantage). Each of the multiple sensors of sensor 100 can comprise an array of one, two, or more ultrasound transducers, (e.g., multiple piezo and / or CMUT transducers), such that the multiple arrays of ultrasound transducers can pivot relative to each other, yet otherwise function as a single array of transducers (e.g., multiple arrays that collectively provide a larger effective sensing area than any of the individual arrays, yet can pivot relative to a neighboring array to provide more flexibility as compared to a single area of similar area). In some embodiments, sensor 100, and / or another component of system 10, is configured to monitor and / or otherwise determine the relative positions between multiple sensors 100 (e.g., multiple individual and / or multiple sets of two or more pixel transducers and / or other piezoelectric sensors as described herein). The relative positions of the sensors 100 can be used for one or more purposes, such as to perform beamforming across the sensors, stitching together of images (e.g., fingerprint images or other tissue images), and other functions associated with the relative position of multiple sensors 100. In some embodiments, delivering and / or receiving ultrasound energy (e.g., by the multiple sensors of sensor 100) is used to determine the position of those sensors and / or other sensors of sensor 100.

[0129]

[0124] In some embodiments, user device 500 comprises all or a portion of sensor 100, and / or all or a portion of controller 200.

[0130]

[0125] In some embodiments, user device 500 comprises one, two, or more devices for which access to the user device 500 and / or user operation of the user device 500 is provided after a confirmation routine (also referred to as an “identification routine) is performed by system 10. A confirmation routine can comprise one, two, or more confirmation routines selected Docket No. ORC-012-PCT from the group consisting of: identification of a user, such as via one or more fingerprints of the user (e.g., as described herein); recognition of the user’s face; confirmation of acceptable “health condition” of the user (e.g., the user is alive, and / or the user is in a safe physical and / or mental state); confirmation that the user is not under significant influence of alcohol and / or drugs (e.g., the user is not intoxicated per applicable standards); and combinations of these.

[0131]

[0126] User device 500 can comprise a cell phone, such as a smartphone.

[0132]

[0127] User device 500 can comprise a device that is worn by a user, such as a smartwatch or other watch device.

[0133]

[0128] User device 500 can comprise a computer device, such as a laptop or a tablet.

[0134]

[0129] User device 500 can comprise a user protection device, such as a gun or a taser.

[0135]

[0130] User device 500 can comprise a transportation device, such as a car, motorcycle, bus, boat (e.g., a yacht), airplane, helicopter, and / or other vehicle.

[0136]

[0131] User device 500 can comprise a piece of equipment (e.g., construction equipment), such as a bulldozer, crane, and / or excavation device. User device 500 can comprise a piece of lab equipment.

[0137]

[0132] User device 500 can comprise a “card device”, such as a credit card, personal ID card, passport, and / or driver’s license.

[0138]

[0133] User device 500 can comprise a memory storage device such as a USB drive.

[0139]

[0134] User device 500 can comprise a crypto wallet device.

[0140]

[0135] User device 500 can comprise a user device selected from the group consisting of: a door lock; a medicine cabinet lock; a storage device such as a gun storage container and / or a storage facility; child lock; and combinations of these.

[0141]

[0136] User device 500 can comprise a medical device. For example, user device 500 can comprise a medical device configured to provide a therapy, such as when system 10 is configured (e.g., via data provided by sensor 100) to confirm the identity of a healthcare professional that, once confirmed, sets and / or modifies the therapy provided by the medical device. User device 500 can comprise a medical device that allows input of medical information, such as when system 10 is configured (e.g., via data provided by sensor 100) to confirm the identity of a healthcare professional that, once confirmed, can enter and / or modify the medical information. In some embodiments, system 10 can be configured to be used by multiple healthcare workers (e.g., doctors, nurses, and / or other healthcare workers that are configured as users of a device 500), where different users have different levels of authority, where the different levels of authority correlate to different levels of permissions in Docket No. ORC-012-PCT changing or accessing medical information of a patient, and / or changing settings of a user device 500 (e.g., changing therapeutic parameters of a user device 500 comprising a medical device).

[0142]

[0137] User device 500 can comprise two, three, or more devices selected from the group consisting of: a phone such as a smartphone or other cell phone (“smartphone” or “cell phone” herein); a computer device; a user protection device; a transportation device; a piece of equipment; a card-based device; a memory storage device; a crypto wallet device; medical device; other user device (e.g., as described herein); and combinations of these.

[0143]

[0138] As described herein, system 10 can comprise FOB 600. In some embodiments, user device 500 comprises FOB 600. In some embodiments, FOB 600 comprises all or a portion of sensor 100, and / or all or a portion of controller 200. FOB 600 can be configured to transmit information to user device 500, such as via a wired and / or wireless connection. In some embodiments, FOB 600 comprises at least a portion of sensor 100 (e.g., and at least a portion of controller 200) and is configured to identify one or more fingerprints of a user and / or otherwise perform a confirmation routine on a user, as described herein. In these embodiments, once the user can be confirmed by FOB 600 (e.g., it is an acceptable user and / or the user is in an acceptable health condition), this confirmation can be transmitted to user device 500 (e.g., a user device that otherwise is not configured to perform a fingerprint scan and / or other user confirmation). In some embodiments, FOB 600 comprises a sensor 100 that comprises an ultrasound-based fingerprint sensor 100a, and a light-based sensor 100b (e.g., a light-based sensor configured as a pulse oximeter such as a reflective oximeter), such as when sensor 100a is transmissive of the light sent by sensor 100b (e.g., when sensor 100b is positioned behind the sensor 100a).

[0144]

[0139] FOB 600 can comprise sensor 100, such as when sensor 100 comprises at least an ultrasound-based sensor as described herein. Alternatively or additionally, FOB 600 can comprise a sensor 100 comprising a physiologic sensor (e.g., a pulse oximeter or other lightbased physiologic sensor). For example, FOB 600 can comprise a sensor 100 comprising a first sensor 100a that comprises an ultrasound-based sensor (e.g., a fingerprint sensor) and a second sensor 100b that comprises a light-based sensor whose light transmissions travel through sensor 100a (e.g., when sensor 100a is configured to pass light therethrough), such as is described in United States Patent Number 10,691,912.

[0145]

[0140] FOB 600 can be configured to identify the fingerprint of a user, and / or perform another user identification as described herein and transfer the confirmation of the particular Docket No. ORC-012-PCT user to user device 500 (e.g., when user device 500 does not include a fingerprint sensor or other sensor to identify a user).

[0146]

[0141] In some embodiments, system 10 is configured to identify a user using two, three, or more identification routines (e.g., as described herein) selected from the group consisting of ultrasound-based fingerprint identification; capacitive sensor-based fingerprint identification; life-sign recognition (e.g., using a pulse oximeter or other light-based physiologic sensor); life sign identification; and combinations of these, such as are described herein.

[0147]

[0142] In some embodiments, system 10 is configured to perform a calibration routine, such as a calibration routine configured to calibrate a sensor 100 comprising a single sensor, and / or a sensor 100 comprising multiple sensors (e.g., multiple similar and / or dissimilar sensors). In some embodiments, system 10 is configured to perform a calibration routine after a portion of system 10 is damaged (e.g., a portion of sensor 100 and / or a portion of user device 500 proximate sensor 100 is damaged) or otherwise is functioning improperly, such as to allow use of system 10 after this calibration is performed. For example, sensor 100 can comprise an array of elements (e.g., ultrasound elements), and after damage to some of the elements is detected, a calibration routine can be performed in which the non-damaged portions of sensor 100 are used, the damaged portions are no longer used, and an identification routine of the present inventive concepts can successfully be performed using the non-damaged portions of sensor 100. In another example, user device 500 can comprise a cell phone that has a cracked portion of a screen of user interface 550 through which sensor 100 sends and / or receives transmissions, and the calibration routine can be performed to accommodate the cracked screen and allow successful completion of a user identification routine. In some embodiments, a device 500 can be modified after an initial calibration routine, after which a second calibration routine is performed (e.g., must be performed). For example, user device 500 can comprise a cell phone upon which a protective case, screen protector, or other covering is added, and system 10 can be configured to perform a calibration routine (e.g., a second calibration routine) to compensate for the added covering. In some embodiments, algorithm 60 comprises an Al or other algorithm that is configured to determine (e.g., in a confirmation routine) which subset of elements of an array of elements (e.g., pixel elements) of sensor 100 are to be used (e.g., to image a fingerprint or other object), such as to compensate for damage of housing 510 and / or other portion of sensor 100, to adjust for a covering having been added to device 500, and / or to otherwise select a subset of elements of sensors 100 to be used. Docket No. ORC-012-PCT

[0148]

[0143] System 10 can be configured to authenticate a user or group of multiple users in a financial transaction, such as a bank transfer. In some embodiments, multiple devices 500 (e.g., multiple cell phones), each including a sensor 100, are used to authenticate a single user and / or multiple users.

[0149]

[0144] In some embodiments, system 10 is configured to perform a confirmation routine multiple times during the use of device 500, such as to confirm the user has not changed, and / or the user’s health condition has not changed. For example, system 10 can require successful completion of a confirmation routine on a repeated basis (e.g., a periodic and / or random basis), such as when the user device 500 comprises a car, plane, and / or piece of equipment, and repeated confirmations are required to prevent one or more of switching of users; prolonged use by a single user; and / or use by a user whose health condition has become unacceptable.

[0150]

[0145] In some embodiments, system 10 comprises a first component Cl (e.g., FOB 600) that comprises a first sensor 100a, and a second component C2 (e.g., device 500) that comprises a second sensor 100b. Sensor 100a can be configured to collect two different forms of data from a user, such as data classified as “confidential data” (e.g., fingerprint data, facial recognition data, voice recording data, and / or other data the user may wish to remain confidential), data CD herein, and data classified as “non-confidential data” (e.g., facial recognition data, voice recording data, physiologic data such as current physiologic data), data NCD herein. Sensor 100b can be configured to at least collect non-confidential data NCD. In an authentication procedure, Cl can collect both confidential and non-confidential data from a user, CDi and NCDi respectively, and C2 can collect non-confidential data (e.g., similar non-confidential data) from the user, NCD2. Data NCDi and NCD2 can be collected at the same time (e.g., the user interfaces with Cl and C2 simultaneously or at least within a short time period, such as within minutes). The data NCD2 can be transmitted from C2 to Cl. Cl can perform a confirmation routine of the user via first confirming the user based on the confidential information CDi collected by Cl. Once that confirmation is successfully completed, Cl can perform a comparison of NCDi and NCD2, in order to confirm the non- confidential data NCD2 collected by C2 is from the same user. If the comparison indicates the same user interfaced with each device, data representing a confirmation of the user can be transmitted from Cl to C2. In these embodiments, confirmation of a user can be provided to a device (e.g., C2 as described hereinabove), without C2 ever receiving the confidential information of the user (i.e. the user can use their fingerprint, facial image, voice data, and / or other data that the user wants to remain confidential in a confirmation routine for the user, Docket No. ORC-012-PCT without having to share that confidential data with a device separate from FOB 600). In some embodiments, C2 can be configured to perform a confirmation routine comprising receiving NCDi from Cl (e.g., after Cl confirms CDi is associated with the correct user), where C2 compares the received NCDi to the NCD2 collected by C2. In some embodiments, Cl comprises FOB 600, and C2 comprises a user device 500 (e.g., cell phone, computer, an ATM or other financial transaction device, and the like). In some embodiments, NCDi and NCD2 comprise data input by a user (e.g., not recorded by the associated sensor 100). For example, NCDi can comprise an alphanumeric or other code that is presented to the user (e.g., via Cl) and entered by the user into C2 as NCD2, such as when configured as a 2-factor authentication routine. In some embodiments, data CD and / or data NCD is collected from multiple users of system 10, such as when a first user confirms the identity of a second user, or confirmation from multiple users is required in order to perform an event (e.g., a financial transaction). In some embodiments, component Cl described hereinabove (e.g., FOB 600) is configured for single use (e.g., a single confirmation of the user), and FOB 600 can be destroyed or otherwise disposed of after its use. In some embodiments, FOB 600 is configured for use (e.g., and provided) by an accredited agency (e.g., a notary, a government authority, or the like) to a user. For example, the agency can identify the user via one or more means (e.g., driver’s license, passport, fingerprint, facial recognition, and / or voice recognition), and then configure FOB 600 to be assigned to the user (e.g., via collecting and storing in FOB 600 data representing the user’s fingerprint, face, voice, or other data collectable by an integrated sensor 100), such as to perform future confirmation routines for that user (e.g., to provide confirmed electronic digital signatures such as those provided by service providers such as DocuSign, provide an alternative to a notary, and the like).

[0151]

[0146] In some embodiments, a confirmation routine performed by system 10 can be configured to confirm multiple fingerprints from a user (e.g., as pre-assigned by the user and / or system 10), such as at least one from each hand of the user. During a confirmation routine, the multiple fingerprints are collected (e.g., by sensor 100) and confirmed (e.g., by algorithm 60). In some embodiments, a particular sequence of collecting the fingerprints is also required for proper confirmation (e.g., a sequence pre-assigned by the user and / or by system 10). In some embodiments, system 10 provides feedback to the user (e.g., via user interface 550, and / or 650) as to which fingerprint is to be collected next (e.g., via a graphical image of the user’s left and / or right hands).

[0152]

[0147] In some embodiments, user device 500 comprises a housing (e.g., housing 510 described herein), such as a metal or plastic housing surrounding at least a portion of each of Docket No. ORC-012-PCT user interface 550, communicator 570, functional assembly 580, and / or functional element 599. For example, user device 500 can comprise a smartphone including user interface 550 comprising a touch screen defining the front of the phone and a housing surrounding the back and sides of the phone. In some embodiments, as described herein, sensor 100 can be integrated into user interface 550, such that sound produced by and received by sensor 100 travels through at least a portion of user interface 550. Alternatively or additionally, sensor 100 can be integrated into housing 510 of user device 500, such that sound produced by and received by sensor 100 travels through at least a portion of housing 510 (e.g., when the user places their finger on a portion of housing 510), as described herein.

[0153]

[0148] In some embodiments, accessory device 700 comprises a device configured to be positioned on or otherwise proximate (e.g., positioned to surround at least a portion of) user device 500, for example when device 700 comprises a protective device, such as a screen protector and / or a phone case. Sensor 100 (e.g., at least a portion of sensor 100) can be integrated into accessory device 700. In some embodiments, sensor 100 (e.g., a sensor 100 positioned within a cover-based accessory device 700 and / or a sensor 100 positioned within user device 500) is configured to receive power from user device 500, such as wirelessly transmitted power provided via inductive coupling. Alternatively or additionally, sensor 100 can receive power from a wired connection of user device 500, such as when sensor 100 (e.g., sensor 100 integrated into accessory device 700) connects to user device 500 via a USB connection. In some embodiments, sensor 100 is configured to communicate with user device 500, such as via a wired or wireless communication (e.g., via NFC, Bluetooth, or other short-range wireless communication methods).

[0154]

[0149] In some embodiments, user interface 550 includes an integrated ultrasound-based sensor 100, such as a sensor 100 comprising an array of conductors (also referred to as “wires”, “lines” and / or “electrodes” herein) in an orthogonal and / or other X-Y arrangement. The sensor 100 can be constructed and arranged to have a relatively thin profile, such as a sensor 100 with a thickness less than or equal to 40pm, and / or 20pm. The user interface 550 can comprise an “exposed surface area” (e.g., a user viewable, contactable, and / or otherwise accessible surface area) that is at least 25mm2in area, such as at least 10,000mm2, and / or at least 40,000mm2. In some embodiments, sensor 100 is configured to record swiping motion of a user’s finger, and a user interface 550 into which sensor 100 is integrated can comprise an area of at least 5mm2and / or 10mm2. An ultrasound-based sensor 100 can be integrated into a user interface 550 such as when the sensor 100 is adhesively attached to or directly deposited onto (e.g., without the use of adhesives) a display (e.g., an OLED, microLED, Docket No. ORC-012-PCT

[0155] LCD, and / or other display) of user interface 550. An ultrasound-based sensor 100 can include a detection area that is at least 50% of the exposed surface area of the interface 550 (e.g., at least 50% of the viewable portion of the integrated OLED or other display). In some embodiments, an ultrasound-based sensor 100 can have a detection area that is at least 75%, 85%, and / or 95% of the interface 550 exposed surface area. In some embodiments, the detection area of the ultrasound-based-sensor 100 has an area of at least 10,000mm2, 40,000mm2, and / or 1,000,000mm2, and / or has a major axis of at least 20cm, 40cm, and / or 80cm. The ultrasound-based sensor 100 can be configured to detect contact of a user (e.g., contact via one or more fingers of a user), record fingerprints and / or other physiologic information of a user, or both. The ultrasound-based sensor 100 can comprise an X-Y arrangement of conductors (e.g., as described herein) that are positioned at varied densities, such as varied separation distances between conductors. For example, at least one portion of a detection area can have a density sufficient to identify a fingerprint of a user, while at least one other portion can be at a lower density, such as a density sufficient to detect contact of a user. In some embodiments, the ultrasound-based sensor 100 is relatively transparent, or includes one or more relatively transparent portions, such that light passes through the sensor 100, such as to allow a user to visualize a display positioned beneath the sensor 100 and / or to allow diagnostic light (e.g., for pulse oximetry) to travel through the sensor 100. As described herein, a user interface 550 comprising an integrated sensor 100 can comprise a multi-layer (e.g., laminate) construction. In these embodiments, the thickness of one or more layers can be based on the acoustic wavelength of ultrasound transmitted and / or received by the sensor 100 of the user interface 550. For example, the user interface 550 can comprise an adhesive layer that has a thickness that is configured to maximize ultrasound transmission through that layer.

[0156]

[0150] Sensor 100 can comprise an ultrasound-based sensor comprising one or more portions (e.g., layers) that are deposited (e.g., sputtered onto, spun onto, printed onto, baked on, thin film deposited, vapor deposited, lithography deposited, and / or otherwise directly deposited) onto a layer of one or more materials selected from the group consisting of: a platen or other substrate layer (e.g., a glass or plastic platen as described herein); a surface of a display (e.g., an OLED or other display); a previously deposited layer of sensor 100; any layer of material (e.g., a substrate layer of a user interface 550); and combinations of these. In these embodiments, sensor 100 can be relatively fixed to another component (e.g., a layer of interface 550 as described herein), without the need for any adhesive. Docket No. ORC-012-PCT

[0157]

[0151] In some embodiments, a user interface 550 comprises a first ultrasound-based sensor 100a, and a second ultrasound-based sensor 100b. In these embodiments, the first sensor 100a and the second sensor 100b can be positioned on opposite sides of a display (e.g., an OLED or other display) of interface 550. The first sensor 100a can be relatively transparent (e.g., include at least one relatively transparent portion) such that the first sensor 100a can be positioned above the display (e.g., without obstructing a user’s view of the display). In these embodiments, the user interface 550 can be integrated into a device 500 (e.g., a cell phone, tablet, and / or other handheld electronic device) and user input (e.g., commands and / or images such as fingerprints) can be captured via user contact (e.g., finger contact) on either or both sides of the device.

[0158]

[0152] In some embodiments, a user interface 550 comprises two displays that are positioned on either side of an ultrasound-based sensor 100.

[0159]

[0153] In some embodiments, device 500 (e.g., including a user interface 550 with an integrated ultrasound-based sensor 100) comprises a controller for a gaming device (e.g., a gaming table or other gaming device including a user-interface portion with a detection area comprising a major axis or a major diameter of at least 20”, 30”, and / or 40”). For example, user interface 550 can comprise a sufficient detection area and be configured to allow use by multiple users, such as multiple users that are sitting in chairs and / or standing in an arrangement that allows a comfortable space between the users. In some embodiments, user interface 550 is configured to differentiate touch between different users (e.g., via fingerprint recognition) as described herein.

[0160]

[0154] In some embodiments, sensor 100 is flexible, such as when sensor 100 comprises wires (e.g., transmit and / or receive wires) that are directly deposited onto a layer of piezoelectric material.

[0161]

[0155] In some embodiments, sensor 100 comprises a set of wires (e.g., transmit and / or receive wires), wherein at least a portion of the set of wires are positioned at varied density (e.g., varied separation distances between pairs of wires).

[0162]

[0156] System 10, via sensor 100, can be constructed and arranged to identify, characterize, and / or differentiate contact by multiple fingers, simultaneously or sequentially, such as at least 2, 3, 4, 5, 6, and / or 11 fingers. In some embodiments, the multiple fingers are fingers of multiple users, such as at least 2, 3, 4, 5, 6, and / or 11 fingers collectively of multiple users.

[0163] In some embodiments, sensor 100 comprises a first sensor 100a positioned on a first user interface 550a and a second sensor 100b positioned on a second user interface 550b, and system 10 (e.g., a system being used by multiple users to play video games or other multi Docket No. ORC-012-PCT user programs) is configured to detect one or more fingerprints of each of one or more users, via each sensor 100. Alternatively or additionally, system 10 can be configured to identify (e.g., via algorithm 60) one or more fingerprints from multiple users via a single sensor 100 (e.g., a single sensor 100 integrated into a single display of a user interface 550, such as a single display which is accessed by the fingers of multiple users). For example, device 500 or another system 10 component can be configured to detect multiple fingerprints such as to differentiate one user from another (e.g., to control an application based on the particular user providing the input), and / or to differentiate one finger from another finger of a single user (e.g., to control an application by which particular finger of a particular user is providing the input). In some embodiments, sensor 100 comprises at least one high-density sensing area, and at least one low-density sensing area, such as when the high-density sensing area comprises sets of X and Y conductors that are closer together than those of the low-density sensing area. In these embodiments, the high-density sensing area can comprise one, two, or more areas that are configured to detect fingerprints from two or more users. In these embodiments, a multi-user confirmation can be required to perform a task, such as to initiate a medical procedure, a weapon strike, a large financial transaction, and / or other event in which agreement to initiate from multiple users is required. In some embodiments, device 500 comprises a vehicle (e.g., a plane) and / or a piece of equipment, in which multiple users control device 500, such as when confirmation of the identity of both users is performed by device 500 via sensor 100 (e.g., fingerprint detection and / or other confirmation as described herein as detected by one, two, or more sensors 100). In these embodiments, after user identification, certain functions of the device may be available to one user (e.g., one of two pilots, or one of two equipment operators) that are not available to the other user, and / or vice versa. In some embodiments, device 500 comprises a large-scale user interface device that can be positioned in a public place (e.g., an airport or town square) and accessed by multiple users (e.g., at least 3, 5, or 10) simultaneously. For example, the device 500 can comprise a user interface 550 with a large aspect ratio (e.g., large width as compared to height), such as to be used by multiple users simultaneously to: request transportation, order a meal, make a reservation, and the like. In this configuration, system 10 can be configured to differentiate one user from another based on fingerprint data obtained via sensor 100, such as if users change their position when accessing the device 500.

[0164]

[0157] In some embodiments, sensor 100 comprises an ultrasound-based sensor 100 that is configured to capture (e.g., image) a portion, such as a majority, of a user’s hand (e.g., a majority of a palm), where a particular user can be identified by the captured hand data. Docket No. ORC-012-PCT

[0165]

[0158] In some embodiments, sensor 100 comprises an ultrasound-based sensor 100 that comprises sets of X and Y conductors as described herein. The thickness, width, and / or length of these conductors can be based on the layer (e.g., a platen) on which the conductors are located. In some embodiments, the piezoelectric layer comprises polyvinylidene fluoride (e.g., applied as large sheets or spun on similar to a photoresist process), and the sensor 100 can be operated in the 25MHz to 50MHz frequency range. Alternatively, or additionally, the piezoelectric layer can comprise Zinc Oxide (ZnO). In some embodiments, the piezo layer comprises a layer with a thickness of between 9pm and 10pm. For a resolution of 1mm, the conductors can be positioned with a periodicity of 1mm (e.g., 0.5mm conductor width with 0.5mm spacing). For a sensor 100 with larger resolution, the periodicity can be increased accordingly. The length of the X and Y conductors can be based on the particular use (e.g., application) of sensor 100, such as to accommodate a large display (e.g., a display with a major axis or major diameter of at least 20”, 30”, and / or 40”) for a gaming device (e.g., a gaming table) and / or public display application, or a relatively small display applicable to a cell phone. Longer conductors will tend to have an increased thickness, such as to reduce overall resistance of the conductor. Thickness of the conductors can be at least 0.1pm, such as at least 0.2pm, 0.5pm, 1.0pm, and / or 2.0pm. In some embodiments, conductor thickness is chosen based on power requirements of the system.

[0166]

[0159] In some embodiments, system 10 is configured to capture a fingerprint of a user at an accelerated rate. System 10 can identify a user’s fingerprint in two steps, a fingerprint “data acquisition” step, and a fingerprint “data processing” step. The data acquisition step includes acquiring the user’s fingerprint information and converting analog data produced by sensor 100 (e.g., an ultrasound-based sensor as described herein), to digital data that can be processed by controller 200 (e.g., processed by algorithm 60 comprising an Al algorithm and / or other algorithm). Subsequently, the data processing step can be performed in which controller 200 processes the sensor 100 data, such as processing which occurs in several steps in order to determine whether or not a particular user is confirmed via the fingerprint data.

[0167]

[0160] The duration of the data acquisition step is dependent on the number of transmit and receive events (TR-RX events) performed by sensor 100, which are dependent on the numbers of X and Y conductors that are used to transmit and receive (e.g., all conductors present and / or a subset of those), and the number of parallel read-outs (e.g., signal acquisition of all the X or Y conductors). The data acquisition time TDA, can be determined by the following: Docket No. ORC-012-PCT

[0168] TDA = (Number of TX-RX events) x (Duration of a single TX-RX event) x (Number of Averages)

[0169]

[0161] In some embodiments, sensor 100 comprises 250 transmit conductors (e.g., 250 X conductors) and 250 receive conductors (e.g., 250 Y conductors), where a single conductor is used to transmit and a single conductor is used to receive in each TR-RX event. In this configuration the total number of TR-RX events is equal to: 250 times 250 divided by 2, or 31,250.

[0170]

[0162] The duration of a single TX-RX event is the minimum wait time that is needed between sequential TX-RX events. This wait time is based on the time it takes for the ultrasound echoes reverberating inside the sensor 100 platen to die down (to avoid an overlap of echoes before consecutive TX-RX events), and the wait time is determined by parameters that include the sensor 100 platen material speed of sound, thickness, and associated attenuation. In some embodiments, sensor 100 comprises a ZnO sensor, and the wait time can be approximately Ips.

[0171]

[0163] “Averaging” is a term used to define the process of acquiring a set of replicate measurements from the same TX-RX location, then taking the average of all these measurements. Averages reduce the noise and increase the signal-to-noise ratio by filtering out uncorrelated noise that usually exists in electronic systems. Higher numbers of averages yield higher signal-to-noise ratio (SNR) values, and system 10 can be configured to perform a minimum number of averages (e.g., 16 or more). In some embodiments, system 10 does not perform averaging.

[0172]

[0164] In some embodiments, sensor 100 comprises 250 transmit conductors and 250 receive conductors, as described hereinabove, and the current total data acquisition time without averaging equals 31.25ms, and with averaging equals 500ms. In some embodiments, system 10 includes additional (e.g., more than two) parallel read-out circuits (e.g., includes more electronic circuitry and its associated power drain and product volume). For example, system 10 can include 16 read-out circuits, and the associated data acquisition times will be reduced to 3.9ms and 62.5ms (without and with averaging, respectively). In some embodiments, sensor 100 is configured to reduce data acquisition time.

[0173]

[0165] In some embodiments, sensor 100 can comprise an ultrasound-based sensor comprising a deposition of a piezoelectric on a platen (e.g., a glass platen), along with conductors (e.g., metal lines) above and below the piezo layer. The piezoelectric (e.g., zinc oxide, ZnO) can be deposited directly onto a display (e.g., an OLED or other display) of user interface 550. The sensor 100 can be of relatively thin construction, such as when Docket No. ORC-012-PCT comprising a thickness of no more than 40pm, 30pm, and / or 20pm. As described herein, sensor 100 can be integrated into user interface 550 without the need for an adhesive bond (e.g., without the need for an epoxy layer and / or other adhesive attachment of sensor 100 to a display or other layer component of interface 550). Sensor 100 and user interface 550 can be manufactured in a single process. In some embodiments, sensor 100 and user interface 550 are tested (e.g., manufacturing quality tested) as a single assembly (e.g., a user interface 550 comprising an integrated sensor 100). In some embodiments, sensor 100 comprises an ultrasound-based sensor comprising X and Y conductors as described herein, and at least one set of the conductors is deposited onto a substrate (e.g., glass) portion of a display (e.g., an OLED or other display) of user interface 550, and / or a portion of a housing 510 of device 500, prior to the entire display being manufactured (i.e. one or more portions of the display are assembled to the display after the depositing of the X and / or Y conductors). The conductors can be deposited onto a portion of a display, a housing, and / or another component of device 500 or system 10, such as via sputtering, lithography, and / or other depositing process (e.g., as described herein). Manufacture of an integrated sensor 100 (e.g., an interface 550 or housing 510 with an integrated sensor 100) can be performed in an assembly line (e.g., one after the other) manufacturing process, and / or in a batch mode (e.g., a mode in which multiples, such as at least 10 at a time are manufactured, such as when conductors of at least 10 sensors 100 are simultaneously deposited (e.g., onto a corresponding at least 10 displays of 10 user interfaces 550 or otherwise).

[0174]

[0166] In some embodiments, sensor 100 comprises a “flexible sensor” such as a sensor that includes one or more flexible portions or is relatively flexible in its entirety. Sensor 100 can comprise an ultrasound-based flexible sensor including a flexible layer of polyvinylidene fluoride (PVDF). In these embodiments, device 500 can comprise a “flexible device” such as a device that comprises one or more flexible portions that support some level of bending, such as a credit card configured to support slight bending (e.g., when located in a wallet) without being damaged. Sensor 100 can comprise a flexible sensor that is attached to (e.g., directly deposited onto or adhesively attached) a display (e.g., an OLED or other display), such as a display of user interface 550.

[0175]

[0167] In some embodiments, sensor 100 comprises an ultrasound-based sensor comprising X and Y conductors, as described herein, and the sensor 100 is further configured as a capacitive-touch sensor (e.g., detect contact of a user based on a measured capacitance change). In these embodiments, sensor 100 can be configured to transfer between a low power capacitive touch sensing mode and a higher power ultrasound transmitting and Docket No. ORC-012-PCT receiving mode (e.g., a mode in which at least two sets of at least 128 conductors, or at least 256 conductors actively transmit and receive ultrasound waves). In these embodiments, sensor 100 can comprise a detection area that occupies a majority (e.g., at least 50%, 75%, 85%, and / or 95%) of the exposed surface area of a user interface 550 into which sensor 100 is integrated. In some embodiments, the detection area of sensor 100 (e.g., an ultrasound-based sensor as described herein) has an area of at least 10,000mm2, 40,000mm2, and / or 1,000,000mm2and / or has a major axis of at least 20cm, 40cm, and / or 80cm.

[0176]

[0168] In some embodiments, sensor 100 comprises an ultrasound-based sensor (e.g., comprising X and Y conductors as described herein) that is configured to be integrated into a user interface 550 comprising a relatively thick glass layer through which ultrasound waves are transmitted and received. The relatively thick glass layer can be configured to reduce breakage, and / or to avoid the need for a screen protector (e.g., a screen protector commonly attached to a cell phone screen for protection). The user interface 550 (e.g., the device 500 into which the user interface 550 and sensor 100 is integrated) can be configured to operate in harsh environments, such as when used in military applications, outdoor use, and / or waterbased activities.

[0177]

[0169] A user interface 550 comprising an ultrasound-based sensor 100 can be configured to detect touch of one or more fingers of a user while the finger is covered by a fabric or other flexible material (e.g., gloves or finger cots). In these embodiments, a user may apply one or more fingers to a surface imageable by sensor 100 (e.g., after removing a covering of the one or more fingers), such that the user’s identity can be confirmed (e.g., via one or more fingerprints and / or other physiologic confirming information of the user). After the confirmation, the user’s fingers can be covered (e.g., re-covered) and sensor 100 can receive various forms of user input (e.g., icon selection, and the like) while the one or more fingers used remain covered.

[0178]

[0170] A user interface 550 comprising an ultrasound-based sensor 100 can be integrated into a device 500 comprising an automated teller machine (ATM) or other banking device.

[0179]

[0171] As described herein, a user interface 550 comprising an ultrasound-based sensor 100 can be flexible (e.g., include one or more flexible portions), such as when the device 500 comprising user interface 550 comprises a wearable device including a flexible “smart screen”. The device 500 can comprise a wearable computer device, and / or an article of clothing, that includes user interface 550. The device 500 can include a first portion (e.g., a watch or article of clothing) that includes sensor 100, and a second portion (e.g., a cell phone, laptop, tablet, and / or other electronic user device) that receives information from the first Docket No. ORC-012-PCT portion (e.g., via wireless communication). In some embodiments, the first portion is configured to perform a user confirmation routine, such as to allow one or more functions (e.g., “smart functions”) provided by the first portion to only be enabled after access by an allowed (e.g., “authorized”) user is confirmed (e.g., via fingerprint detection performed by the first portion and / or the second portion).

[0180]

[0172] User device 500 can comprise a medical device, as described herein. In some embodiments, a user interface 550 comprising an integrated sensor 100 (e.g., an ultrasoundbased sensor 100) is configured to confirm the identity of a nurse, doctor, and / or other authorized caregiver (e.g., via fingerprint identification) prior to allow setting and / or changing of any parameters of the medical device (e.g., turning on, turning off, and / or modifying any setting of the device 500). Alternatively or additionally, the device 500 can be configured, via the sensor 100, to detect and / or measure (“detect” or “measure” herein) life signs and / or other physiologic parameters of the user (e.g., including fingerprints), such as to confirm proper use and / or adjust therapy provided by the device 500 based on the physiologic parameter measurements.

[0181]

[0173] In some embodiments, user interface 550 comprises an alphanumeric keypad and / or other keyboard. In these embodiments, an ultrasound-based sensor 100 integrated into user interface 550 can detect one or more fingerprints of one, two, or more users, such as while the associated one or more users are typing (e.g., entering data via typing) into the user interface 550. In some embodiments, system 10 (e.g., via algorithm 60) is configured to repeatedly confirm a user’s identity during data entry (e.g., to avoid a permitted user to initiate data entry after which a second, non-permitted user continues to enter data). The repeated confirmation can be continuously repeated based on a time interface (e.g., at least every 10, 20 or 30 seconds), and / or based on the amount of data entered (e.g., repeatedly after no more than 20, 40, or 60 characters are entered). Alternatively or additionally, system 10 can be configured to confirm an identify of a user via capture of a fingerprint (e.g., one or more fingerprints), and as long as the finger remains in contact (e.g., continued contact at a pressure level above a threshold) with the portion of system 10 (e.g., user interface 550) used to capture the fingerprint, it can be assumed that the particular user is providing input to system 10 (e.g., to device 500). However, if the finger “loses contact”, system 10 can be configured to require the repeating of a user confirmation routine (e.g., again record and identify the user via their fingerprint or other method), such as to allow continued control of device 500 by that user (e.g., continued control that is also dependent on continuous contact of the user with the associated device). Docket No. ORC-012-PCT

[0182]

[0174] In some embodiments, sensor 100 comprises an assembly comprising a first ultrasound-based sensor 100a and a second ultrasound-based sensor 100b, the two sensors 100 arranged in a stacked arrangement. In these embodiments, the first sensor 100a can be configured to detect a first set of one or more forms of user input, and the second sensor 100b can be configured to detect a second set of one or more forms of user input. In these embodiments, the first set of one or more forms of user input can include at least one form of user input that is not included in the second set of one or more forms of user input, and / or vice versa. For example, the first sensor 100a can be configured to detect a fingerprint of one or more users, while the second sensor 100b may not have the resolution to perform a proper fingerprint detection. The first sensor 100a can be configured to transition from a sleep state to an awake state based on detection of user contact by the second sensor 100b. Controller 200 can comprise a single electronic module for interfacing (e.g., for transmitting and / or receiving signals) with both sensor 100a and 100b, or it can comprise a distinct separate electronic module for each.

[0183]

[0175] In some embodiments, at least a portion of a detection area of a sensor 100 is positioned along an edge of user device 500 (e.g., along an edge of user interface 550 or an edge of housing 510 of device 500). For example, a first portion of sensor 100 (e.g., a set of X and Y conductors, a magnetic switch, and / or other touch-based sensor) positioned along an edge of device 500 can be configured, when contacted (e.g., activated) by a user, to cause a second portion of sensor 100 (e.g., a high-density portion) to transition from a sleep state to an active state. In some embodiments, the first portion of sensor 100 is configured to measure a force applied by a user (e.g., one or more user’s fingers, such as when a tapping and / or squeezing force is applied to one or more edges of device 500), such as when the transition in states only occurs when the applied force exceeds a threshold. In some embodiments, the first portion determines the level of force applied by measuring the amount of the user’s skin in contact with the first portion, as described herein.

[0184]

[0176] In some embodiments, sensor 100 comprises an ultrasound-based sensor comprising sets of X and Y conductors, as described herein. In these embodiments, sensor 100 can comprise a portion Pv that includes one or more portions (e.g., all) of sensor 100, where each portion Pv comprises sets of X and Y conductors that are positioned in a high-density layout, such that these portions can operate in a low-density, medium-density, and / or high-density mode of operation (e.g., providing low, medium, and / or high resolution, respectively, based on the quantity of conductors used to transmit and / or receive). For example, when a portion Pv is operated in a low-density mode, every other, every third, or every “«th” conductor (e.g., Docket No. ORC-012-PCT every nthX conductor) is used to transmit ultrasound waves (e.g., and a corresponding subset of Y conductors is configured to receive reflected ultrasound waves). Medium-density and high-density modes involve increasing numbers of conductors being used to transmit and receive. When portion Pv is operated in a low-density mode (e.g., a low power mode of device 500) and contact is made by a user (e.g., a user’s finger) to a location proximate portion Pv (e.g., contact is made to a portion of user interface 550 directly above portion Pv of sensor 100), at least portion Pv(e.g., portion Pv and one or more portions of sensor 100 proximate portion Pv) transitions to a medium-density or high-density mode of operation, in which at least more (or all) of the X and Y conductors are used in a transmit and receive fashion as described herein. In these embodiments, device 500 can normally (e.g., most of the time) operate in a low power mode (e.g., due to the low-density transmit and receive mode of portion Pv), but transition to a higher power mode in which portion Pv operates in the medium-density or high-density modes of operation described hereinabove. This configuration of portion Pv allows the user to, on demand, transition sensor 100 (e.g., as an integrated part of user interface 550) from a low power, low-density mode, to a higher power, medium-density and / or high-density mode (e.g., at least portion Pv of sensor 100 operates in the greater density mode). This arrangement of portion Pv has numerous advantages, such as: saving battery life of a device 500, where the high-power usage of the high-density mode is only encountered when needed (e.g., as initiated by a user and / or by system 10 on a relatively infrequent basis); and / or faster image (e.g., fingerprint) acquisition time and lower data storage needs (e.g., associated with scanning only the reduced portion Pv). In some embodiments, a first “contact” (e.g., through one or more layers of user interface 550) of portion Pv causes portion Pv to transition from a low-density mode of operation to a mediumdensity mode of operation, and a second contact of portion Pv causes portion Pv to transition from a medium-density mode of operation to a high-density mode of operation. In some embodiments, a user causes the transition to high-density mode in order to have their fingerprint detected (e.g., have their identity confirmed). In some embodiments, portion Pv transitions automatically to a low-resolution mode after a time period has elapsed (e.g., a time period in which no user contact and / or no other user input is received). In some embodiments, portion Pv transitions from a low-density mode to a medium-density and / or a high-density mode on an event selected from the group consisting of: a portion of housing 510 of device 500 is touched (e.g., touched by the user); user interface 550 is touched (e.g., touched by the user); a particular time of day is reached; a user physiologic parameter reaches a threshold; device 500 is manipulated (e.g., rotated or shaken) in one or more ways, such as Docket No. ORC-012-PCT when detected by a sensor-based functional element 999; when a particular application (e.g., gaming application or other application) is being used on device 500; and combinations of these. In some embodiments, portion Pv is operated in a high-density mode and confirms a user via their fingerprint, after which portion Pv enters a low-density mode. Portion Pv can remain in the low-density mode as long as the finger providing the fingerprint remains in contact with device 500 (e.g., with user interface 550). If loss of contact (e.g., with sensor 100 via interface 550) is detected, portion Pv can transition to a high-density mode (e.g., and require the user to confirm their fingerprint an additional time).

[0185]

[0177] In some embodiments, sensor 100 and / or other components of system 10 are configured to create an image of a biological material such as blood or other biological material, such as biological material that is positioned (e.g., directly and / or on a side) proximate a user interface 550 comprising an integrated sensor 100. In these embodiments, system 10 can be configured (e.g., via algorithm 60) to perform an analysis of the biological material (e.g., saliva, blood, plasma, and / or cells), such as to determine blood type, the presence of a pathogen, blood glucose, and / or another detectable parameter of the biological material (e.g., of a substance within the biological material). Analysis of the blood and / or other biological material can be performed using a time-shift image, an amplitude-shift image, or both, such as are described herein. In some embodiments, sensor 100 and / or other components of system 10 are configured to create an image of an inorganic substance, such as to perform an analysis of the inorganic substance.

[0186]

[0178] In some embodiments, controller 200 is configured to provide drive signals to sensor 100, and / or to receive and process signals recorded by sensor 100 (e.g., one or more recorded reflections of one or more ultrasound signals transmitted by sensor 100 in response to the drive signals provided by controller 200). Controller 200 can implement various beamforming techniques, such as time domain and / or frequency domain beamforming techniques, that can be used to drive sensor 100 and / or to reconstruct images from the signals received from sensor 100. For example, controller 200 can implement time domain beamforming by acquiring and storing a time series of the echo or echoes (“echo” or “echoes” herein) for each transmit and receive combination. Using this implementation, controller 200 can use the entire time series to reconstruct an image (e.g., a fingerprint image captured by sensor 100). Alternatively or additionally, controller 200 can implement frequency domain beamforming techniques. For example, controller 200 can perform frequency domain beamforming by oversampling the received signals, such as by acquiring and storing a time series of the echo for each transmit and receive combination and extracting Docket No. ORC-012-PCT the I / Q components of those signals using software, such that the image can be reconstructed using those I / Q components. Alternatively or additionally, controller 200 can use an I / Q demodulator to extract the I / Q components of the signal (e.g., without oversampling) and use hardware extracted I / Q values for image reconstruction. In other embodiments, controller 200 can use a pair of analog to digital converters (ADCs) to perform I / Q sampling.

[0187]

[0179] In some embodiments, sensor 100 comprises one or more “ultrasonic film layers”, such one or more piezo-material layers from which ultrasound waves can be transmitted and / or received.

[0188]

[0180] In some embodiments, sensor 100 is positioned beneath the display of user interface 550. System 10 can be configured to reconstruct the image of a fingerprint of a finger placed on the top side of the display via ultrasound signals transmitted and received by sensor 100, these signals passing through the display (e.g., through one or more glass layers or other materials of the display). Controller 200 can be configured to provide drive signals to sensor 100 to transmit ultrasound energy, and to process the received echoes of these ultrasound transmissions from the finger positioned on the display, such as is described herein. Controller 200 can be configured to minimize the effects of overlapping reflections caused by the various layers of sensor 100 and / or the display. In some embodiments, controller 200 uses a baseline, with a tuned center frequency configured to create opposite phases of overlapping echoes. In some embodiments, system 10 can be configured to acquire image data without an object (e.g., a finger) placed on the scanner platen (e.g., with an air interface to the sensor), such as to record a baseline. Controller 200 can be configured to use the baseline recording to process an image of an object (e.g., a finger), for example to extract signals of interest from a signal recorded by controller 200. Controller 200 can be configured to use a subtraction or other image processing techniques to compare the baseline recording to the signals recorded during the object imaging process to identify signals of interest. In some embodiments, controller 200 can use frequency tuning to enhance recorded signals, for example by tuning the center frequency of the drive signal to cancel out incident reflections caused by various interfaces in sensor 100 and / or the display. In some embodiments, controller 200 can use phase demodulation to reconstruct images, for example in cases where tone burst is too long and interferes with the reflection. In these cases, the signal of interest becomes the superposition of the incident signal and the reflected signal, which can be analyzed using phase demodulation.

[0189]

[0181] In some embodiments, sensor 100 is configured to perform a first step to prepare a portion of sensor 100 and / or user interface 550 for a subsequent, second imaging step, for Docket No. ORC-012-PCT example a second step comprising an image data acquisition step. For example, sensor 100 can be configured to precondition a portion of sensor 100 or another portion of device 500 (e.g., a portion of the display or platen) to improve an imaging process.

[0190]

[0182] In some embodiments, system 10 is configured to perform time domain beamforming (e.g., as described herein), such as when acquiring and storing a time series of the echo for each transmit-receive (TX-RX) combination. System 10 can use the time series (e.g., the entire time series) to perform image reconstruction. This configuration provides superior image quality as the data represents multiple frequencies. This configuration provides flexibility in choosing the technique for image reconstruction, since an entire time series of interest can be acquired.

[0191]

[0183] In some embodiments, system 10 is configured to perform frequency domain beamforming and / or oversampling (e.g., as described herein), such as when acquiring and storing a time series of the echo for each TX-RX combination. System 10 can extract (e.g., via an algorithm contained in instructions stored in memory) I / Q components from the time series, and then use the extracted components for image reconstruction. This configuration provides a simple, straight-forward approach for acquiring I / Q components, and it provides flexibility in choosing I / Q samples in the acquired time window. This configuration also provides flexibility in choosing a technique for image reconstruction (e.g., since the entire time series of interest can be acquired).

[0192]

[0184] In some embodiments, system 10 is configured to perform frequency domain beamforming with I / Q demodulation (e.g., as described herein). System 10 can extract (e.g., in hardware) I / Q components using an I / Q demodulator (e.g., a dedicated I / Q demodulator), and then sample (e.g., using an analog-to-digital converter, ADC) and store I / Q values for each TX / RX combination. The I / Q data is then used for image reconstruction. This configuration lowers data storage requirements (e.g., memory requirements) as well as data transfer requirements. This configuration also reduces sampling requirements, lowers analog-to-digital converter requirements (e.g., enables the use of a lower cost, lower speed ADC), and reduces power requirements (e.g., enables the use of a lower speed ADC which requires less power).

[0193]

[0185] In some embodiments, system 10 is configured to perform frequency domain beamforming with I / Q sampling (e.g., as described herein). System 10 can be configured to extract (e.g., in hardware) I / Q components using two ADCs with quadrature phase shift, for example essentially combining an I / Q demodulator and ADC in the same hardware. The stored I / Q data can be used for image reconstruction. This configuration lowers data storage Docket No. ORC-012-PCT requirements (e.g., memory requirements) as well as data transfer requirements. This configuration also reduces sampling requirements, lowers analog-to-digital converter requirements (e.g., enables the use of a lower cost, lower speed ADC), and reduces power requirements (e.g., enables the use of a lower speed ADC which requires less power). This configuration avoids the need for dedicated I / Q demodulation hardware, reducing associated power required and cost.

[0194]

[0186] In some embodiments, fingerprints from a set of multiple fingers of a particular user can each be assigned to a particular set of instructions to be performed by device 500. In these embodiments, detection of a first fingerprint (e.g., a fingerprint of an index finger or other finger) of a user can be assigned to a first task, and detection of a second fingerprint (e.g., a fingerprint of a middle finger or other non-index finger) can be assigned to a second task, and so on. In this arrangement, tasks that otherwise might take multiple steps (e.g., multiple keystrokes on user interface 550) can be reduced to the single step of placing the particular finger proximate sensor 100 (e.g., on a portion of housing 510 of device 500 or on user interface 550 at a location proximate sensor 100) to cause the task to be performed. Applicable tasks can include but are not limited to: transition from a locked state to an unlocked state; transition from an unlocked state to a locked state; cause a screen of user interface 550 to go blank or otherwise change states; dial the phone number of a particular person; enter an alarm state; dial 911; enter a particular software program or other function of device 500; and the like. In some embodiments, different fingerprints are independently correlated to a task that unlocks a device with an associated set of various levels of user permissions. For example, a first fingerprint (e.g., a fingerprint of the user’s dominant thumb) can fully unlock a device, a second fingerprint (e.g., the fingerprint of the user’s index finger) can unlock the device in a partially secure mode, such as a “kids mode”, and / or a third fingerprint (e.g., the fingerprint of the user’s non-dominant thumb) can unlock the device in a “false unlock” mode. In some embodiments, a false unlock mode can comprise a mode of operation where device 500 appears to be fully unlocked, however sensitive user information remains inaccessible, becomes further encrypted (e.g., requiring additional user and / or third-party information to decrypt), and / or is automatically deleted when false unlock mode is activated. The use of various fingerprints to activate different use modes can allow the user to covertly activate various modes, for example when required to unlock a device under duress (e.g., when under investigation by a nefarious organization or nefarious individual). Docket No. ORC-012-PCT

[0195]

[0187] In some embodiments, system 10 is configured to perform IQ sampling of received ultrasound signals, for example IQ sampling that is implemented in electronic hardware of system 10 (e.g., electronic hardware of controller 200), as described herein. Extracting IQ samples from the RF data in hardware reduces the amount of data to be transferred out of sensor 100, and increases data rates. To extract the IQ samples in hardware (e.g., hardware of controller 200 and / or sensor 100), an ADC that has a sampling frequency of 4x the sensor operating frequency can be implemented in a first configuration. The ADC will then output a series of data corresponding to I, Q, -I, -Q, I, Q, -I, -Q, (repeating). In a second configuration, two ADCs that are 90 degrees out of phase (quadrature phase) are included, with a sampling frequency equal to lx the sensor 100 operating frequency. In this configuration, one ADC outputs I samples, and the other ADC outputs Q samples. In a third configuration, two ADCs that are 90 degrees out of phase are included, with a sampling frequency of 2x the sensor 100 operating frequency. One ADC will then output {I, -I, I, -I, (repeating)} samples, and the other ADC will output the Q equivalent. These three configurations offer a trade-off between added noise and ADC sampling frequency. For example, the first configuration requires the highest sampling frequency out of the three. However, since the data is sampled with a single ADC, there are no potential issues of timing offsets / jitter between two ADCs. Of course, the ADC itself can still have sampling (e.g., aperture) jitter. On the other hand, the second configuration offers the lowest sampling rate out of the three configurations, at the expense of more phase noise sources due to using two parallel ADCs that need to be exactly 90 degrees out of phase. The third configuration offers twice as many samples as the second configuration, which allows acquiring more IQ data in a given time window, and having more IQ samples for IQ averaging.

[0196]

[0188] In some embodiments, system 10 is configured to perform “Carry-out RF averaging” before RF filtering in the front-end circuitry, such as to reduce ASIC resource requirements and increase scan throughput of sensor 100. Two configurations that can be implemented in the sensor 100 ASIC front-end are RF averaging and RF filtering. Both serve the purpose of increasing signal SNR, and also reducing the impact of noise. RF filtering can be performed using a finite impulse response (FIR) digital filter. Carrying out the RF filtering operation requires convolving the input signal with the filter coefficients, and under certain operation conditions, this filtering can be time and resource consuming if done for each RF data (not averaged). Since both RF averaging and FIR filtering are linear operations, these operations can be performed in any order. Carrying out RF averaging before RF filtering is advantageous, as this reduces the number of filtering operations by a factor of N, where N is Docket No. ORC-012-PCT the number of RF averages used. This reduces ASIC resource requirements such as data storage, and can increase scan throughput if RF filtering of each RF data is a bottleneck in the data processing chain. Another benefit is to relax the limitations on the FIR filter design (e.g., number of coefficients), which is usually adjusted to meet throughput requirements. Under certain conditions, this reduces noise and increases RF and image SNR.

[0197]

[0189] In some embodiments, system 10 is configured to perform data bit truncation. Due to digital filtering and accumulation (averaging without division by # averages) operations such as digital FIR filtering, RF accumulation, and IQ accumulation, the data width (e.g., IQ data) increases from the ADC output (input to the first operation) until the output of the final operation. Under certain conditions, it is required to truncate the output data from the final operation down to the same number of bits as the ADC output data (e.g., ADC output = 16 bits, output data from last operation = 48 bits, truncated final data = 16 bits). Deciding at which bit position to start bit truncation is an important sensor 100 configuration consideration, and in some configurations, an ASIC provides the flexibility of choosing between different start positions for truncation. Bit truncation can be used to maximize the RF signal dynamic range, in order to reduce quantization noise. To choose the different start positions of bit truncation, the following process can be used:

[0198] (1) start by considering all the factors that impact the signal level including accumulation, signal level change due to different sensor 100 “sensor stacks” (the various layers that make up sensors 100), signal variation due to manufacturing process variation within the sensor 100 and between different sensors 100.

[0199] (2) estimate the range (e.g., ratio) the signal is expected to change due to each of these different factors.

[0200] (3) convert the range to a number of bits (e.g., 8x = 3 bits, 3x = 2 bits).

[0201] (4) add up all the #bits needed to cover the total change in signal level (e.g., 10 bits), and divide that number uniformly with the number of bit truncation levels the ASIC allows.

[0202]

[0190] In some embodiments, system 10 is configured to provide drive signals to sensor 100 and to perform image reconstruction at different frequencies. In a typical operation, sensor 100 drive signals are at the same frequency in which image reconstruction is performed (filtering, delay profile calculations, and the like). Under certain conditions, it can be advantageous to drive sensor 100 and do image reconstruction at different frequencies. In one configuration, sensor 100 is driven at a frequency fc that generates harmonic components at 2fc or 3fc. Then, system 10 performs filtering at 2fc / 3fc and image reconstruction, which Docket No. ORC-012-PCT can yield increased image quality and increased imaging resolution without having the ASIC drive the sensor 100 at the higher frequencies. In another configuration, the ASIC is limited in bandwidth (Tx and / or Rx), but drive frequencies at higher frequencies can still yield increased image quality. In this configuration, the ASIC can drive sensor 100 at a lower frequency than the signal frequency used for image reconstruction. Of course, since the signal is filtered away from the center frequency, the signal level will not be maximized. However, maximizing the RF signal level does not always correspond to the highest image quality (SNR / contrast).

[0203]

[0191] In some embodiments, different configurations of system 10 exhibit a trade-off between SNR and image resolution, such as when beamforming with a “row-column addressed array”. When focusing at the image plane with a row-column addressed array, a smaller area is effectively interrogated at the image plane in order to improve image resolution. However, since an orthogonal line is received, this interrogation does not translate to maximized Rx signal level and therefore not maximized Rx signal SNR. Maximizing Rx signal level occurs when transmitting with a plane wave (all Tx lines firing without focusing). These two configurations describe two extremes during image optimization. Often, the best image is achieved at a focal depth D that is different from the image plane, since focal depth D provides a better trade-off between SNR and resolution, and the overall image quality is higher (image SNR and contrast).

[0204]

[0192] Various metrics can be used to optimize image quality, such as SNR (e.g. optimized by maximizing PV), and / or contrast. In some embodiments, system 10 is configured to perform image optimization by maximizing image contrast. System 10 can comprise an image optimization algorithm (e.g., algorithm 60), in which image contrast is optimized (maximize separation between reflector / absorber distributions). Then, parameters that yield optimal image contrast are used. In addition, since image SNR is another key image optimization metric, PV (peak-to-valley ratio) can be used instead of contrast, and / or in addition to contrast, to find the optimal beamforming parameters.

[0205]

[0193] Various methods for finding optimal frequency can be used, such as time domain methods and / or frequency domain methods. In time domain methods, a pulse excitation can be used, then the FFT of the Rx echo is computed to find the one or more resonant frequencies. In frequency domain, the drive frequency is swept, and one or more frequencies that yield the highest signal amplitudes are identified (amplitude peals), which correspond to the resonant frequencies. Docket No. ORC-012-PCT

[0206]

[0194] In some embodiments, system 10 (e.g., at least sensor 100) is calibrated to find an optimized frequency of operation and / or other optimized operating parameters of sensor 100. During the calibration process, an optimized frequency of operation can be found by driving sensor 100 at a set of different frequencies (e.g., 10MHz to 40MHz, for example in steps of 1MHz), after which the frequency that yields the highest signal amplitude is found (e.g., based on I / Q data). The optimal frequency of operation can comprise the frequency that maximizes the acoustic transmittance within sensor 100 (e.g., within the sensor stack).

[0207]

[0195] In some embodiments, sensor 100 (e.g., and / or another component of system 10) is calibrated using a “simulation-based calibration method”. In some embodiments, a sensor 100 calibration is done experimentally. Additionally, or alternatively, a simulation model can be used, the simulation model being tuned (or trained in case of an Al model) using a preset amount of test data. The simulation model can then predict the optimal imaging parameters based on a certain set of data, such as the frequency response.

[0208]

[0196] In some embodiments, sensor 100 is configured to be calibrated to work with a screen protector (e.g., when sensor 100 comprises a display with a screen protector and / or is located under a display with a screen protector, such as an aftermarket screen protector). When adding a screen protector (e.g., a functional element 99 comprising a screen protector) on top of a display of system 10, the received echo signal is changed due to the screen protector (e.g., a change in: signal level, how the reflections add up, the time of flight, and the like). The placement of a screen protector can be detected (e.g., by sensor 100 and / or another component of system 10) by comparing data produced before and after adding the screen protector. Other information can be deduced from the frequency response, such as the screen protector thickness, the screen protector material, and potentially the thickness of an adhesive layer located between the display and the screen protector. Based on this information, beamforming parameters can be optimized by system 10, such as to optimize image quality.

[0209]

[0197] In some embodiments, performance testing, calibration, and / or other testing performed in the design and / or manufacturing of sensor 100 can be performed using one or more phantoms or test targets, such as a test target comprising a “Ronchi” design (e.g., a Ronchi target). In some embodiments, a test target comprises a square-wave pattern of bars and spaces that can be ultrasonically imaged by sensor 100. One or more images of the test target can be analyzed to calculate various metrics of sensor 100, such as image SNR, resolution, contrast, and / or distortion.

[0210]

[0198] Ronchi targets using PDMS / RTV material can be mass produced at low cost. In some embodiments, a Ronchi pattern is transferred to a mask, and a mold is created using a silicon Docket No. ORC-012-PCT wafer. Then, RTV / PDMS-based wafers of Ronchi samples are fabricated, that can be divided into individual Ronchi targets.

[0211]

[0199] A Ronchi target material can comprise an acoustic impedance similar to (e.g., identical to) the acoustic impedance of the top most layer in the sensor 100 sensor stack (closest to the user side). Patterns of ideal of near ideal reflectors and absorbers can be generated using this Ronchi target material. However, this is not always possible, such as in configurations using metal and glass. PDMS or RTV Ronchi targets with high acoustic impedance can be created, and these targets being flexible, can conform to the surface of sensor 100. For example, one such material is RTV160, which has an acoustic impedance of 1.5 (acoustic impedance of skin is 1.8). In another configuration, RTV material is mixed with glass and / or metal particles, such as to increase the acoustic impedance (in the case of glass or metal platens) while keeping the Ronchi target sufficiently flexible.

[0212]

[0200] In embodiments including ceramic materials with low conductivity, the bottom metal lines of sensor 100 can be deposited directly on the ceramic instead of using a glass substrate. The PVDF and top electrodes can be included next in the sensor 100 fabrication process. This configuration avoids the need for an adhesive layer to bond the glass and the ceramic, which eliminates the associated adhesive attenuation and the multiple reflections in glass. In some embodiments, a glass substrate is included, such as to achieve acoustic resonance in the glass, and to optimize (e.g., to increase to an optimal level) acoustic transmission through the entire sensor stack.

[0213]

[0201] In some embodiments, system 10 is configured to perform a calibration of one or more sensors 100. In a first phase of a calibration procedure, the response of sensor 100 can be tuned. First, system 10 can sweep the ASIC Tx drive frequency to determine one or more resonant frequencies of sensor 100 (e.g. a sweep from 10MHz to 50MHz in steps of 1MHz). Second, system 10 can compute Rx amplitude for each frequency and pick the one or more frequencies with highest amplitude. Third, one or more ASIC parameters can be adjusted based on the results of the second step. Fourth, system 10 can store the resonant frequency list for imaging operation of sensor 100. Fifth, using the same data (e.g., the frequency sweep data), system 10 can be configured to identify one or more missing channels of sensor 100 (e.g., channels that are not functioning as expected). In some embodiments, if the results of the first phase of calibration are within an acceptable threshold range, for example if at least one resonant frequency is identified, and / or the number of missing channels is lower than threshold, sensor 100 can “pass” the first phase of calibration. Otherwise, sensor 100 can be discarded (e.g., when calibration is performed in a manufacturing process). In a second Docket No. ORC-012-PCT phase of a calibration procedure, one or more image parameters can be tuned. First, an imaging phantom, such as a Ronchi target, can be placed on the surface of sensor 100. Second, an image tuning “script” can be run, where multiple images of the phantom are generated using different imaging parameters. Third, an analysis of the images can be performed to select the imaging parameter values that maximize the image quality metric. Fourth, an SNR analysis of one or more of the images generated using the selected imaging parameters can be performed. In some embodiments, if the SNR exceeds a threshold, sensor 100 can pass the second phase of calibration. Otherwise, sensor 100 can be discarded and / or the optimization can be repeated.

[0214]

[0202] In some embodiments, one or more parameters of system 10 is selected (e.g., in a design or manufacturing process) based on the target resolution of an image to be produced by sensor 100. For example, one or more parameters of sensor 100 can comprise the frequency, the line pitch, and / or the line spacing. In a first step, the frequency of operation of sensor 100 can be selected based on target image resolution. Second, given the selected frequency and speed of sound in the material of the sensor stack of sensor 100, the wavelength can be calculated. Third, given the calculated wavelength, Tx line pitch and Rx line pitch can be selected, for example a pitch that minimizes image artifacts, such as artifacts generated due to grating lobes (e.g. a pitch to wavelength ratio of <= 0.7). In some embodiments, the selected Tx line pitch and Rx line pitch are not equal. In a fourth step, the spacing between the lines can be selected. In some embodiments, a larger pitch yields a smaller number of channels for a given sensor 100 (e.g., when a larger number of channels does not provide a benefit). In some embodiments, the largest pitch (lowest number of channels) that achieves the desired image quality (e.g. pitch / lambda = 0.7), can be selected. In some embodiments, a smaller spacing (gap between lines) is desired to maximize the line width, which in turn, maximizes the signal level (which is proportional to the active area of sensor 100). However, a wider element also means a smaller acceptance angle, and this needs to be taken into account when assessing image quality. Also, a smaller spacing tends to create more electrical crosstalk between lines.

[0215]

[0203] Referring collectively to FIGS. 2 through 19, various configurations of a sensor 100 and system 10 are illustrated, such as ultrasound-based systems and sensors that utilize a time-shift image as described herein.

[0216]

[0204] Many security systems and electronic devices use biometric sensing for user authentication. Compared to other authentication methods (e.g., text-based passwords, Docket No. ORC-012-PCT cognitive passwords, graphical passwords, passphrases, public key cryptography), biometric authentication uses a person’s unique biological, physiological, or behavioral characteristics to verify their identity. These biological characteristics can be found as patterns in a person’s fingerprints, facial expressions, irises, speech patterns, and other features. Due to their uniqueness, biological characteristics are typically harder to spoof than passwords, and therefore biometric authentication can be advantageously combined with other authentication methods to improve overall security.

[0217]

[0205] Fingerprint-based authentication is one type of biometric authentication that records the ridges and valleys that make up a person’s fingerprints. Compared to other types of biometric authentication, fingerprint-based authentication benefits from sensors that are small, robust, and manufacturable at high volumes and low cost. As a result, fingerprintbased authentication has become widespread, finding use in mobile devices, automated teller machines (ATMs), and door locks, among other devices and applications.

[0218]

[0206] To implement fingerprint-based authentication, a digital image of a candidate’s fingerprint is recorded, typically using an ultrasound, capacitive, optical, or thermal scanner. Regardless of which scanning technology is used, the fingerprint must be recorded with a spatial resolution high enough to differentiate between the ridges and valleys. For example, the Federal Bureau of Investigation (FBI) and the National Institutes of Standards and Technology (NIST) established a standard resolution of 500 pixels per inch for automatic fingerprint identification systems (AFISs), corresponding to a pixel imaging size of 50 microns. A pattern-matching algorithm can then compare the digital image to a database of fingerprints of “allowed” individuals. If a match is found, the security system infers that the candidate is one of the allowed individuals. In this case, the security system can then grant access to the candidate.

[0219]

[0207] Many ultrasound scanners use an ultrasound transducer array that can both transmit and sense ultrasound. For example, consider a two-dimensional transducer array forming rows and columns of pixel elements (“pixel elements” or “pixel transducers” herein). The transducer array can be affixed to a bottom face of a platen, and each pixel element can be driven to emit an ultrasound pulse into the platen. Part of the ultrasound pulse reflects off the top face of the platen and propagates back to the transducer array as an echo. One or more pixel elements sense the echo, and the resulting waveform can be processed to obtain a pixel of a corresponding image. When a finger contacts the top face of the platen, the resulting image will reveal the fingerprint of the finger. Docket No. ORC-012-PCT

[0220]

[0208] Prior-art ultrasound scanners measure the change in echo energy caused by ridges contacting the top face of the platen. For example, consider a valley of a finger contacting the top face. In this case, a pocket of air is formed between the top face and the skin, and therefore no skin directly contacts the top face. An ultrasound pulse emitted into this region of the platen will reflect off the top face with a large reflection coefficient due to the relatively large difference between the mechanical impedances of the platen (typically glass or plastic) and air. The resulting valley echo will have a relatively high energy. However, where a ridge directly contacts the top face, the difference between the mechanical impedances of the platen and skin is smaller. In this region of the platen, the ultrasound pulse will reflect off the top face with a smaller reflection coefficient, resulting in a ridge echo with a relatively low energy. Therefore, a fingerprint image can be obtained by mapping echo energy across the two-dimensional top face of the platen. Additional details about fingerprint imaging based on echo energy can be found in International Publication No. WO 2019 / 032590, titled “Interactive Biometric Touch Scanner”, and Gerard Touma, “A rowcolumn addressed acoustic biometric scanner integrated with pulse oximetry” (Ph.D. Dissertation, Stanford University, 2020); each of these references is incorporated herein by reference in its entirety.

[0221]

[0209] The present inventive concepts can use ultrasound to image fingerprints by recording the spatial variation in echo phase, or time delay, as an alternative to, or in addition to the spatial variation in echo energy. Specifically, a ridge echo is phase-shifted with respect to a valley echo, and therefore the transducer array will detect, for a ridge echo, a round-trip pulse travel time that is different from that of a valley echo. A fingerprint image can be obtained by mapping echo phase, and / or pulse travel time, across the two-dimensional top face of the platen.

[0222]

[0210] Advantageously, fingerprint images obtained with the present inventive concepts have a higher signal-to-noise ratio (SNR) than images obtained with prior-art energy -based techniques (see FIG. 9). As described in more detail below, the higher SNR likely arises from the fact that echoes have less phase noise relative to their amplitude noise. Accordingly, phase can be measured with higher precision than amplitude. This relatively less phase noise may be due to: ultrasound pulses being generated with less phase noise, as compared to amplitude noise; and / or receive electronics having less electronics phase noise.

[0223]

[0211] Accordingly, the present inventive concepts utilize time-based, rather than amplitudebased, signal processing techniques to process waveforms of sensed echoes. For example, each pixel element can be used to record a baseline waveform when no finger contacts the Docket No. ORC-012-PCT platen, and a signal waveform when a finger does contact the platen. The baseline waveform can be processed to determine a baseline arrival time of a baseline echo, and the signal waveform can be processed to determine a signal arrival time of a signal echo. The baseline arrival time can then be subtracted from the signal arrival time (or vice versa) to obtain a time shift for the pixel element. The time shift will be relatively closer to zero for pixel elements near valleys, and relatively farther from zero for pixel elements near ridges.

[0224]

[0212] As described in more detail below, there are many ways to process a waveform to determine an echo arrival time, some of which originate from the field of ultrasound timedomain reflectometry. For example, many ultrasound transducers are excited with a tone burst, i.e., an integer number of continuous cycles of a single-frequency sinusoid. In this case, the echo will also have the form of a tone burst, and the arrival time can be defined as the time at which any node or anti-node in the recorded waveform occurs. Signal-processing techniques involving Hilbert transforms or cross-correlations can then be used to determine the time shift. However, other signal processing techniques can be used without departing from the scope hereof. In addition, the present inventive concepts can be used with any type of pulse excitation, and are therefore not limited to tone bursts.

[0225]

[0213] The present inventive concepts extend to operation of a single ultrasound transducer in contact with the platen. For example, a single ultrasound transducer can be used to determine the presence of a finger contacting the top face of the platen by comparing the measured time shift to a threshold. An indication of the presence can then be outputted, such as a binary indication (e.g., “0” or “1”) or a value between 0 and 1 indicating the probability that a finger is present. The single ultrasound transducer can be one pixel element of a transducer array. Alternatively, several pixel elements of the array can be operated to obtain several time shifts, which can be aggregated (e.g., by calculating a mean or variance) to determine the indication. In any case, when the resulting indication indicates the presence of a finger, the transducer array can be controlled to obtain an image of the fingerprint. In this way, the transducer array is only used to image a finger once it is known that a finger is, in fact, present on the platen.

[0226]

[0214] While the above discussion describes fingerprint sensing, the present inventive concepts can be used to detect any object contacting the platen, provided that the presence of the object induces a measurable phase shift in an echo. Furthermore, while the above discussion describes two-dimensional transducer arrays whose pixel elements are arranged linearly in rows and columns, the present embodiments can be implemented with any type of transducer array, including one-dimensional pixel arrangements (e.g., pixel elements Docket No. ORC-012-PCT arranged linearly or circularly), two-dimensional pixel arrangements (e.g., pixel elements arranged in concentric circles), and / or three-dimensional pixel arrangements.

[0227]

[0215] When used for fingerprint sensing, the present inventive concepts can be integrated with other physical, physiological, and biological measurements, such as when included as part of a multi -function biometric system. For example, the above referenced documents (i.e., International Publication No. WO 2019 / 032590, and the Ph.D. dissertation by Gerard Touma) show how a pulse oximeter can be incorporated with an ultrasound transducer array when at least part of the transducer array is at least partially optically transparent (e.g., in the nearinfrared). As another example, the present inventive concepts can be used to determine an area of contact between the finger ridges and platen. This area of contact can be measured over time to identify periodic changes indicative of a pulse. In this way, the biometric system can distinguish between living tissue and inanimate matter. The present inventive concepts can be combined with other sensors and / or biometric functionality without departing from the scope hereof.

[0228]

[0216] FIG. 2 is a perspective view of an ultrasound sensor 3100 that combines an ultrasound transducer array 3104 with a platen 3102. FIG. 3 is a cut-away side view of the ultrasound sensor 3100. The ultrasound transducer array 3104 is bonded to, or fabricated on, a bottom face 3122 of the platen 3102 so that an ultrasonic pulse emitted by the transducer array 3104 propagates through the platen 3102 in the +z direction (see right-handed coordinate system

[0229] 3120) toward a top surface 3112 of the platen 3102. The top surface 3112 is a boundary between materials with different mechanical impedances (e.g., densities and / or stiffnesses). Therefore, the ultrasonic pulse will reflect off the top surface 3112, and the resulting reflection will propagate through the platen 3102 in the -z direction toward the bottom face 3122, where it is detected by the transducer array 3104. This reflection is also referred to as an echo.

[0230]

[0217] The ultrasound transducer array 3104 is row-column addressable. Specifically, the transducer array 3104 has a plurality of row electrodes 3106 that extend in the y direction, and a plurality of column electrodes 3108 that extend in the x direction. Between the row electrodes 3106 and column electrodes 3108 in the z direction is a piezoelectric layer 3114 that can be electrically actuated, via the row electrodes 3106 and column electrodes 3108, to mechanically oscillate, thereby emitting ultrasound waves into the platen 3102. Similarly, the piezoelectric layer 3114, when mechanically actuated by ultrasound waves, produces a timevarying electrical signal that can be subsequently detected and processed. The piezoelectric layer 3114 can be formed from a crystal (e.g., lithium niobate, lithium tantalate, quartz, and Docket No. ORC-012-PCT the like), ceramic (e.g., zinc oxide, lead zirconium titanate, potassium niobate, barium titanate, and the like), III-V or II- VI semiconductor (e.g., aluminum nitride, gallium arsenide, and the like), polymer (e.g., polyvinylidene fluoride (PVDF) and copolymers thereof), and / or any other piezoelectric material.

[0231]

[0218] FIG. 2 shows the Ithrow electrode 3106(i) causing piezoelectric layer 3114 to emit an ultrasound pulse 3116(i) into the platen 3102. Since the row electrode 3106(z) extends across the entire length (in the y direction) of the ultrasound sensor 3100, the ultrasound pulse

[0232] 3116(z) similarly extends across the entire length of the platen 3102. Alternatively, the jthcolumn electrode 3108(y) can cause piezoelectric layer 3114 to emit an ultrasound pulse 3118(7) into the platen 3102. Since the column electrode 3108(j) extends across the entire width (in the x direction) of the ultrasound sensor 3100, the ultrasound pulse 3118(j) similarly extends across the entire width of the platen 3102. In operation, either the row electrode 3106(z) or the column electrode 3108( / ) causes an ultrasound pulse to be emitted (e.g., via a signal applied to the electrode), and the other of electrodes 3106(z) or 3108( / ) is configured to record the received ultrasound pulse. The transverse area (i.e., in the x-y plane) where the row electrode 3106(z) and column electrode 3108(y) overlap is referred to herein as a pixel element (e.g., see pixel elements 3110 in FIG. 3). While FIG. 2 shows the transducer array 3104 with 19 row electrodes 3106 and 17 column electrodes 3108 (corresponding to 19x 17 = 323 pixel elements), the transducer array 3104 can alternatively have any number of row electrodes 3106 and column electrodes 3108 without departing from the scope hereof. For example, the transducer array 3104 can have 512 row electrodes 3106 and 512 column electrodes 3108, corresponding to 512x512 = 262,144 pixel elements. In some embodiments, there is no applicable minimum and / or maximum quantity of row electrodes 3106 and / or column electrodes 3108 applicable to the sensors of the present inventive concepts.

[0233]

[0219] As shown in FIG. 3, the platen 3102 has a thickness dpin the z direction. Since pixel elements 3110 are used to both emit and sense ultrasound waves, the thickness dpcan be chosen such that the duration of an emitted pulse is less than the round-trip propagation time tpin the platen 3102. This requirement ensures that pixel elements 3110 do not emit and sense at the same time, and that electrical leakage (e.g., see leakage 3502 in FIG. 6) does not contaminate an output signal. For example, the platen 3102 can be fabricated from glass with a sound velocity vsof 6000m / s. A pulse with a bandwidth of 45MHz has a bandwidth-limited duration of 22ns, corresponding to sound travel in the z direction of 132 / / m (e.g., forward and Docket No. ORC-012-PCT back travel in a platen 3102 with a thickness of 66pm). However, the pulse can have a greater spatial extent, which can simplify signal processing (e.g., see FIG. 6). In some embodiments, the platen 3102 has a thickness dpof 0.5mm. However, the platen 3102 can have a different thickness dpwithout departing from the scope hereof. Similarly, the platen 3102 can be fabricated from a material other than glass (e.g., plastic, metal, crystal, semiconductor, and the like) without departing from the scope hereof.

[0234]

[0220] When a finger and / or other tissue of one or more users, finger 3130 shown, physically contacts the top surface 3112 of the platen 3102, the ultrasound sensor 3100 can be used to (i) detect the presence of the finger 3130, (ii) image a fingerprint of the finger 3130, (iii) measure a force with which the finger 3130 pushes against the top surface 3112, (iv) measure time variation of the force to determine that the finger 3130 is from a living being (as opposed to a prosthetic), and / or any combination thereof. Accordingly, the ultrasound sensor 3100 can be used as a biometric touch sensor (e.g., see finger sensor system 3700 in FIG. 8). To detect a full fingerprint, the ultrasound sensor 3100 can have an area (i.e., in the x and y direction) of at least 0.1cm2, 0.3cm2, 0.5cm2, 0.7cm2and / or 1cm2. For clarity, the finger 3130 is not drawn to scale in FIGS. 2 and 3, and finger 3130 can comprise a finger, palm, other body part, and / or any other tissue of one, two, or more users of the systems, devices, and methods of the present inventive concepts.

[0235]

[0221] FIGS. 4 and 5 illustrate row-column addressing of the ultrasound sensor 3100 with the finger 3130 contacting the platen 3102. In FIG. 4, a column electrode 3108(y) emits an ultrasound pulse 3118(j) into the platen 3102. In FIG. 5, a row electrode 3106(i) senses echoes 3406, 3408 generated when the ultrasound pulse 3118(j) reflects off the top surface

[0236] 3112. FIGS. 4 and 5 are both side cut-away views through the row electrode 3106(i). For clarity in FIGS. 4 and 5, only ten column electrodes 3108 are shown. FIGS. 4 and 5 are best viewed together with the following description.

[0237]

[0222] The bottom surface of the finger 3130 forms an alternating sequence of ridges 3316 (also referred to as “friction ridges” or “epidermal ridges”) and valleys 3318. The ridge 3316 directly contacts the top surface 3112 of the platen 3102, while the valleys 3318 do not directly contact the top surface 3112. Thus, beneath each valley 3318, air contacts the top surface 3112. Accordingly, the reflection coefficient at the top surface 3112 is larger at the valleys 3318 and smaller at the ridges 3316, and therefore the amplitude of the echo 3408 is larger than the amplitude of the echo 3406. Docket No. ORC-012-PCT

[0238]

[0223] During emission, a signal source 3304 applies a drive signal 3306 to the column electrode 3108(j) while all other column electrodes 3108 and all row electrodes 3106 are grounded, thereby establishing a voltage difference across the piezoelectric layer 3114. For clarity, only the row electrode 3106(i) is shown in FIG. 4 as being grounded. During sensing, an amplifier 3402 amplifies the electrical output of the row electrode 3106(f) into an amplified output 3404 that is subsequently digitized and processed. Emitting with the column electrode 3108(j) and sensing with the row electrode 3106(f) is equivalent to imaging the finger 3130 with a single pixel element 110(i, j). Accordingly, an image of the finger 3130 can be captured by repeating emission and sensing for all combinations of the row electrodes 3106 and column electrodes 3108. Alternatively, emission can be performed with row electrodes 3106, and sensing can be performed with column electrodes 3108.

[0239]

[0224] FIG. 6 shows a waveform 3500W recorded from the row electrode 3106(f) during emission and sensing of one pixel element 3110. The waveform 3500W is a digital sequence of signal values obtained by digitizing the amplified output 3404 (e.g., see analog-to-digital converter 3706 in FIG. 8). The signal values are also time-tagged. At an emission start time of t = 0, the drive signal 3306 was applied to the column electrode 3108(y) to generate the ultrasound pulse 3118(j). In the example of FIG. 6, the drive signal 3306 was a pulse with a center frequency of 150MHz, and a duration of eight cycles of the center frequency (i.e., approximately 53ns). The emission start time t = 0 serves as a reference time for all temporal measurements of the waveform 3500W.

[0240]

[0225] While the drive signal 3306 was applied to the column electrode 3108(y), RF leakage 3502 appeared on the waveform 3500W due to capacitive coupling between the electrodes

[0241] 3106(f) and 3108(j). The RF leakage 3502 died out by 150ns, after which an echo appeared (e.g., one of the echoes 3406 and 3408 in FIG. 5). The portion of the waveform 3500W with the echo is referred to herein as a “sub-waveform” and is shown in FIG. 6 as a subwaveform 3504. The ultrasound sensor array 3100 and drive signal 3306 is designed so that the propagation time of the pulse 3118(f) through the platen 3102 is larger than the time required for the RF leakage 3502 to die out. This requirement allows the sub-waveform 3504 to be distinguished from the RF leakage 3502 and prevents the RF leakage 3502 from contaminating or affecting the sub-waveform 3504. Note that RF leakage 3502 does not always occur, depending on the particular implementation of the ultrasound sensor array 3100. Where RF leakage 3502 does not occur, or where RF leakage 3502 occurs but dies out faster than shown in FIG. 6, the platen 3102 can be made even thinner. Docket No. ORC-012-PCT

[0242]

[0226] FIG. 6 shows that the sub-waveform 3504 occurs at an arrival time tathat is measured with respect to the emission reference time t = 0. The arrival time tacan be defined relative to any feature of the sub-waveform 3504, such as a beginning or end of the sub-waveform 3504, a peak of an envelope calculated from the sub-waveform 3504 (e.g., via a Hilbert transform applied to the sub-waveform 3504), a zero-crossing of an instantaneous phase calculated from the sub-waveform 3504, and / or a peak or zero-crossing of any oscillation of the sub-waveform 3504. The arrival time tacan alternatively or additionally be defined with respect to any phase of any oscillation of the sub-waveform 3504. Another definition of the arrival time tacan be used without departing from the scope hereof. Methods to process the waveform 3500W to determine the arrival time tadepend on the chosen definition and are described in more detail below.

[0243]

[0227] Some of the definitions of the arrival time taare based on a zero-crossing of the waveform 3500W. To facilitate the determination of tain these cases, a mean of the waveform 3500W can be calculated and subtracted from the waveform 3500W. The result is referred to herein as a “mean-corrected waveform”. The waveform 3500W is one example of a mean-corrected waveform, as evidenced by the fact that the waveform 3500W is generally centered at a signal of OmV. Furthermore, since a zero-crossing need only be detected near or within the sub-waveform 3504, the waveform 3500W can be windowed to extract the sub-waveform 3504. The mean of the sub-waveform 3504 can be calculated and subtracted from the sub-waveform 3504. The result is referred to herein as a “mean- corrected sub-waveform”, of which the sub-waveform 3504 is one example. Windowing eliminates a large portion of the waveform 3500W, advantageously speeding up signal processing and reducing the required memory of the associated device or system. In some embodiments, the recording of a waveform begins after the emission start time, in which case some or all of the waveform 3500W prior to the sub-waveform 3504 can be ignored.

[0244]

[0228] In FIG. 6, the echo represented by the sub-waveform 3504 is an initial echo of the ultrasound pulse 3118(j). Specifically, the time delay between the beginning of pulse emission (i.e., t = 0) and the beginning of the sensed echo (i.e., the beginning of the subwaveform 3504) is approximately the round-trip propagation time tp= 2dp / vs. The echo reflects off the bottom face 3122 to create another upward-traveling pulse, which in turn reflects off the top surface 3112 to create a second downward-traveling echo that is sensed starting at 2tp. This process repeats, giving rise to a sequence of sensed echoes that are temporally spaced by tp, and that decrease in amplitude with each reflection (i.e., position in Docket No. ORC-012-PCT the sequence). The sub-waveform 3504 of the initial echo has the largest amplitude (i.e., highest SNR). Accordingly, it is assumed herein that the sub-waveform 3504 represents an initial echo. However, the present embodiments can be readily adapted to record and process a second echo, third echo, etc.

[0245]

[0229] FIG. 7 illustrates a time shift 4t between a baseline sub-waveform 3602 and a signal sub-waveform 3604. Each of the sub-waveforms 3602 and 3604 is an example of a mean- corrected sub-waveform 3504. For clarity in FIG. 7, the sub-waveforms 3602 and 3604 are normalized and overlapped on the same plot. To enhance visibility of the time shift 4t, only a 7-ns-wide portion of the sub-waveforms 3602 and 3604 is plotted.

[0246]

[0230] The baseline sub-waveform 3602 was recorded by a pixel element 3110 with air contacting the top surface 3112 of the platen 3102 in the region directly over the pixel element 3110 (e.g., under a valley 3318 of the finger 3130, or with the finger 3130 completely removed from the platen 3102). By contrast, the signal sub-waveform 3604 was recorded when a ridge 3316 of the finger 3130 contacted the top surface 3112 in the region directly over the pixel element 3110. As shown in FIG. 7, the presence of a ridge 3316 on the top surface 3112 not only reduces the normalized amplitude of the signal sub-waveform 3604 by 44, but also shifts the signal sub-waveform 3604 by 4t. Therefore, the presence or absence of a ridge 3316 can be determined from 4t.

[0247]

[0231] In some embodiments, the drive signal 3306 has the form of a tone pulse, i.e., several consecutive cycles of a single-frequency sinusoid. The sub-waveform 3504 will also have the form of the tone pulse, and therefore can be described using phase rather than time. In these cases, the arrival time tais equivalent to an arrival phase, and the time shift 4t is therefore equivalent to a phase shift A(p. That is, the presence of a ridge 3316 of the top surface 3112 shifts the phase of the baseline sub-waveform 3604 by 4 = fAt X 360°, where f is the frequency of the sinusoid and 360° converts the result into degrees. Accordingly, in the present disclosure, any reference to the time shift At is equivalent to the phase shift A(f) (and vice versa) when the sub-waveform 3504 has a well-defined phase and frequency. However, the drive signal 3306 need not be a tone pulse, and can instead be a different type of pulse and / or excitation waveform.

[0248]

[0232] The time delay At can be either positive or negative. In fact, the sign of At can be used to identify whether the material contacting the platen 3102 is either softer or harder than the material of the platen 3102. As such, the sign of At can also be used to determine what type of object is contacting the platen 3102. Docket No. ORC-012-PCT

[0249]

[0233] FIG. 8 is a block diagram of a finger sensor system 3700 that uses the ultrasound sensor array 3100 to image the finger 3130 based on time shifts 4t. The finger sensor system 3700 can also determine the presence or absence of the finger 3130 on the platen 3102 and determine a force with which the finger 3130 pushes against the platen 3102.

[0250]

[0234] The finger sensor system 3700 includes a real-time processor 3708 that controls a multiplexer (MUX) 3702 to select which of the column electrodes 3108 is driven by the signal source 3304. The real-time processor 3708 also controls the MUX 3702 to select which of the row electrodes 3106 is connected to the input of the amplifier 3402. The amplified output 3404 of the amplifier 3402 is digitized with an analog-to-digital converter (ADC) 3706, whose output is sensor data 3716 that the real-time processor 3708 then timestamps to create the waveform 3500W. The real-time processor 3708 is referenced to a time base 3728 that references all timing of the waveform 3500W, thereby ensuring that all waveforms 3500 are time-stamped with accuracy and stability. Although not shown in FIG. 8, the time base 3728 can also be used as a time / frequency reference for one or both of the ADC 3706 and the signal source 3304.

[0251]

[0235] The processor 3708 comprises a “real-time” processor in that the time it requires to complete an operation is deterministic, and therefore predictable (i.e., does not change based on external factors or unforeseen events). Real-time control of the MUX 3702 and processing of the amplified output 3404 ensures time-stamping is implemented consistently for all waveforms 3500. This consistency is important since each time shift 41 is determined from two waveforms 3500 recorded at different times. A sporadic or unpredictable delay in signal processing, control of the MUX 3702, or both, could result in an erroneous value of the time shift 4t, i.e., the time shift 4t will be erroneously attributed to the presence or absence of the finger 3130 on the platen 3102. Examples of the real-time processor 3708 include a field- programmable gate array (FPGA), digital signal processor (DSP), and a system-on-chip (SoC). However, the real-time processor 3708 can be another type of circuit and / or chip, provided that it operates deterministically. After a waveform 3500W is generated, it can be non-determini stically processed to determine a time shift 4t. As such, the processor 3720 need not be a real-time processor (e.g., it can be a central processing unit).

[0252]

[0236] The real-time processor 3708 transmits the waveform 3500W to a computer 3710 that processes the waveform 3500W to determine the time shift 4t. The computer 3710 includes a processor 3720 and a memory 3722 that stores the waveform 3500W. The memory 3722 also stores machine-readable instructions that, when executed by the processor 3720, process the Docket No. ORC-012-PCT waveform 3500W to determine the time shift 211 from sensor data 3716. The signalprocessing methods used by the computer 3710 to determine the time shift 11 are discussed in more detail below. Additional details about the computer 3710 are described below in relation to FIG. 19.

[0253]

[0237] In some embodiments, the finger sensor system 3700 generates a time-shift image (e.g., see time-shift image 3804 in FIG. 9) from the time shift 211 determined for each pixel element 3110 of the sensor array 3100. Each pixel of the time-shift image uniquely corresponds to one pixel element 3110, and the pixels of the time-shift image are arranged identically to the pixel elements 3110. The computer 3710 can display the time-shift image to a user via a display 3712 that can be integrated with the computer 3710 (e.g., a tablet or laptop computer) or be separate from the computer 3710 (e.g., a desktop monitor or high- definition television). Although not shown in FIG. 8, the computer 3710 can alternatively or additionally communicate with another computer system (e.g., via a wide area network, a local area network, the internet, Wi-Fi, and the like) that uses the time-shift image, such as a biometric security system that processes the time-shift image to determine access to a room, computer system, files, and the like. In some embodiments, the real-time processor 3708 and computer 3710 are combined as a single computer system.

[0254]

[0238] A waveform 3500W recorded by the finger sensor system 3700 when the finger 3130 contacts the platen 3102 is referred to herein as a “signal waveform”. The finger sensor system 3700 can sequentially record one signal waveform 3500W for each pixel element

[0255] 3110 of the ultrasound sensor array 3100. In some embodiments, the finger sensor system 3700 determines the time shift At for each pixel element 3110 using a waveform 3500W that was obtained when the finger 3130 was not contacting the platen 3102 (i.e., air completely contacted the top surface 3112 of the platen 3102). Such a waveform 3500W is referred to herein as a “baseline waveform”.

[0256]

[0239] The finger sensor system 3700 processes the signal and baseline waveforms 3500 for each pixel element 3110 to determine the time shift At for that pixel element 3110. For example, the finger sensor system 3700 can process the signal waveform 3500W to determine a signal arrival time t^ of a signal echo, and the baseline waveform 3500W to determine a baseline arrival time t of a baseline echo. The finger sensor system 3700 can then subtract the baseline arrival time tafrom the signal arrival time tato obtain the time shift A t = ta — ta ■ In other embodiments, the finger sensor system 3700 transforms the signal and baseline waveforms 3500 into a cross-correlation waveform. The finger sensor system 3700 Docket No. ORC-012-PCT then processes the cross-correlation waveform (e.g., by identifying a peak) to determine the time shift 41.

[0257]

[0240] Subtracting the baseline arrival time tafrom the signal arrival time tafor each pixel element 3110 of the ultrasound sensor 3100 is referred to as time (or phase) compensation. Advantageously, time compensation improves accuracy by ensuring that detected spatial variations of time shifts 4t are correctly attributed to ridges 3316 and valleys 3318 of the finger 3130 on the platen 3102. Specifically, baseline time compensation corrects for spatial variability of the round-trip propagation time tp= — across the sensor 3100, i.e., that tpcan vary for different pixel elements 3110 due to spatial variations in the sound velocity vs, the thickness dp, or both. Spatial variability in dpcan be caused by manufacturing limitations, such as when the platen 3102 is fabricated with the top and bottom surfaces 3112, 3122 not flat or not parallel to each other, or when the piezoelectric layer 3114 has a frequency / phase response that spatially varies across the platen 3102. Spatial variability in dpcan also be caused by differential thermal expansion of the platen 3102, which may arise from a transverse temperature gradient across the platen 3102. Such a temperature gradient may be caused by heat that conducts from the finger 3130 into the platen 3102. Thermal gradients can also cause spatial variations in the density of the platen 3102, thereby causing the sound velocity vsto spatially vary as well. Spatial variability of the round-trip propagation time tpmay also be caused by electronics, such as different latencies for different circuit components, different lengths of metallic traces, variations in channel impedances, and / or other inconsistencies within the electronics that may cause spatial variability.

[0258]

[0241] Since many sources of spatial variability of tpare time-dependent, the most accurate values of 4t can be determined from signal and baseline waveforms 3500 that are recorded temporally close to each other (e.g., within one second). However, many sources of spatial variability change slowly enough over time that the baseline arrival times are essentially constant for extended time periods (e.g., minutes or more). In this case, it may not be necessary to record a full set of baseline waveforms 3500 (i.e., one for each pixel element 3110) for each time-shift image. For example, the baseline waveforms 3500 can be recorded once, saved in the memory 3722, and retrieved from the memory 3722 as needed. In this case, the finger sensor system 3700 can periodically (e.g., once every minute) record new baseline waveforms 3500 and overwrite the baseline waveforms 3500 stored in the memory Docket No. ORC-012-PCT

[0259] 3722 with the new baseline waveforms 3500. Alternatively, only the baseline arrival times are stored in the memory 3722 and retrieved from the memory 3722 as needed to determine a time delay 4t. Storing only the baseline arrival times tauses less memory than storing the baseline waveforms 3500, thereby reducing the computational resources needed to generate the time-shift image. It is also possible to correct the stored baseline waveforms 3500 for temperature variations that have occurred since the baseline waveforms 3500 were recorded, thereby increasing the amount of time that can elapse before recording new baseline waveforms 3500.

[0260]

[0242] FIG. 9 compares a time-shift image 3804 of a fingerprint with a conventional amplitude-shift image 3802 of the same fingerprint. To improve signal-to-noise ratio (SNR), each of the images 3802 and 3804 was averaged over sixteen scans. The ultrasound sensor 3100 had 250 x 250 = 62,500 pixel elements 3110 covering an area of 1x1 cm2. The images 3802 and 3804 were obtained from the same signal and baseline waveforms 3500. To generate the amplitude-shift image 3802, the signal and baseline waveforms 3500 for each pixel element 3110 were processed to determine the average amplitude shift therebetween (e.g., see the amplitude shift AA in FIG. 7). Each average amplitude shift was mapped to a grayscale value of a corresponding pixel of the image 3802. For the time-shift image 3804, the average time shift A t determined for each pixel element 3110 was mapped to a grayscale value of a corresponding pixel of the image 3804.

[0261]

[0243] Subtracting the baseline amplitude from the signal amplitude for each pixel element 3110 of the ultrasound sensor 3100 is referred to as baseline amplitude (or power) compensation. Similar to baseline time compensation, baseline amplitude compensation is used to correct for spatial variability of the sensed amplitude (or power) of the echoes, thereby ensuring that spatial variation in AA is correctly attributed to the finger 3130. In fact, baseline-echo amplitude can spatially vary by more than the amplitude shift AA, in which case baseline amplitude compensation is critical for obtaining a clear fingerprint image. Spatial amplitude variability can be caused by any of several factors, including spatial variations in the piezoelectric properties of the piezoelectric layer 3114, electrical variations in the electrodes 3106 and 3108, and readout electronics.

[0262]

[0244] The time-shift image 3804 has a noticeably higher SNR than the amplitude-shift image 3802, as evidenced by the visibly improved contrast of the ridges. This improved SNR likely indicates that ultrasound pulses 3116 are generated with less phase noise than amplitude noise, and thus phase (or time delay) can be measured with better sensitivity than Docket No. ORC-012-PCT amplitude. The higher SNR achievable with the present inventive concepts can be used to improve image clarity, as shown in FIG. 9. However, higher SNR can also be used to advantageously decrease data acquisition time by reducing the number of averages needed to meet a target SNR. For example, a time period of at least l / / s can be used to scan each pixel element 3110, and therefore a full scan of all 62,500 pixel elements 3110 would take place over a time period of at least 62.5ms. However, for amplitude-shift imaging, up to 64 scans can be performed and averaged to obtain an image with sufficient SNR, resulting in a total scan time of at least 4s. By contrast, with time-shift imaging, sufficient SNR can be obtained by averaging over less than 64 scans, such as less than 16 scans, less than 8 scans, such as only four scans. The resulting total scan time for four scans of 0.25s is a factor of sixteen less than what is needed for amplitude-shift imaging. In some embodiments, time-shift imaging is implemented with any positive integer number of scans that are averaged together. These embodiments include time-shift imaging with one scan, in which case no averaging is needed.

[0263]

[0245] The time-shift image 3804 and amplitude-shift image 3802 can be combined to obtain a hybrid time-amplitude-shift image having a higher SNR than either of the images 3802 and 3804. Specifically, each pixel of the hybrid image can be obtained by processing the corresponding signal and baseline waveforms 3500 to obtain both the time shift 41 and the amplitude shift 44. These shifts can then be transformed into a single value (e.g., a weighted sum) that is then mapped to a grayscale value. Other techniques to combine the time shift 41 and amplitude shift 44 can be used without departing from the scope hereof. In some embodiments, either or both a time-shift image 3804 and an amplitude-shift image 3802 can be obtained, a device (e.g., user device 500 described herein) can be configured to first create one or more time-shift images or amplitude-shift images to identify the location of a finger (e.g., on a sensor), and then create one or more amplitude-shift images or time-shift images, respectively, that are used by the device to create a fingerprint of the finger. Alternatively or additionally, the device can be configured to create either or both of time-shift images and / or amplitude-shift images based on a user entered configuration, or a condition identified (e.g., automatically identified) by the device. For example, if one type of image (e.g., of a fingerprint) is not providing sufficient and / or appropriate data (e.g., for user identification), the device can automatically switch to obtaining the other type of image. For example, indications that one or more fingerprint ridges and / or valleys are missing can cause a transition from one type of image capture (e.g., time-shift image or amplitude-shift image) to Docket No. ORC-012-PCT the other type of image capture (e.g., amplitude-shift image or time-shift image, respectively), and / or to transition from a single type of image capture (e.g., time-shift image or amplitude-shift image) to a combination of multiple types of image capture (e.g., a combination of time-shift image and amplitude-shift image). In another example, one type of image (e.g., time-shift image or amplitude-shift image) is used to identify the periphery of a finger placed proximate sensor 3100, and the other type of image (e.g., amplitude-shift image or time-shift image, respectively) is used to capture the fingerprint of the finger (e.g., to improve response time of fingerprint identification).

[0264]

[0246] FIG. 10 shows a fingerprint image 3902 generated using only the signal arrival times of the signal waveforms 3500. Thus, the fingerprint image 3902 of FIG. 10 was generated without baseline compensation (i.e., baseline waveforms 3500). Specifically, the signal arrival time determined for each pixel element 3110 of the ultrasound sensor 3100 was mapped to a grayscale value of a corresponding pixel of the fingerprint image 3902. The fingerprint image 3902 was created from the same signal waveforms 3500 used to generate the images 3802, 3804 of FIG. 9.

[0265]

[0247] FIG. 10 also shows a binarized image 3904 obtained by applying binarization to the fingerprint image 3902. The binarized image 3904 shows almost all of the same features that appear in the time-shift image 3804. Accordingly, the spatial variability of the round-trip propagation time tpmay be small enough that baseline time compensation is not needed. For example, the thickness dpof the platen 3102 may have sufficient spatial uniformity that the baseline arrival times taare essentially identical for all of the pixel elements 3110. In this case, the baseline waveforms 3500 are not needed, advantageously reducing data acquisition time, speeding up signal processing, and reducing memory storage requirements.

[0266]

[0248] FIG. 11 is a flow chart of an ultrasound signal-processing method 31000 that uses baseline time compensation. Method 31000 can be performed using the systems and devices of the present inventive concepts, and it is described using the various components described herein. In the block 31012, a time shift is determined between (i) a signal arrival time of a signal echo sensed by an ultrasound transducer, and (ii) a baseline arrival time of a baseline echo sensed by the ultrasound transducer. In one example of the block 31012, the ultrasound transducer is one pixel element 3110(i, j) of the ultrasound sensor 3100, and the computer 3710 of FIG. 8 processes signal and baseline waveforms 3500 to determine the time shift 11. The signal echo may have been generated by a platen surface, of a platen, with an object contacting the platen surface. Similarly, the baseline echo may have been generated by the Docket No. ORC-012-PCT platen surface without the object. For example, the signal and baseline echoes may have been generated by the platen top surface 3112 of the platen 3102, as shown in FIGS. 2 to 5.

[0267]

[0249] In some embodiments, the ultrasound transducer is a pixel element of an ultrasound transducer array. In these embodiments, the method 31000 includes the decision block 31020, which repeats the block 31012 for each pixel element of the ultrasound transducer array to generate an array of time shifts. The method 31000 also includes the block 31022 in which a time-shift image is generated for the array of time shifts. In one example of the blocks 31020 and 31022, the computer 3710 processes signal and baseline waveforms 3500 to determine one time shift 41 for each pixel element 3110 of the ultrasound sensor array 3100. The onetime shift 4t is one of an array of time shifts corresponding to the two-dimensional array of pixel elements 3110. The computer 3710 then processes the array of time shifts to create a time-shift image (e.g., the time-shift image 3804 of FIG. 9). Although not shown in FIG. 9, the time-shift image can then be outputted (e.g., to the display 3712, or to another computer system for additional processing or storage).

[0268]

[0250] In some embodiments, the ultrasound transducer array has a number of rows (rows of conductors) and a number of columns (columns of conductors), and the time-shift image has the same numbers of rows and columns. For example, the numbers of rows and columns in the time-shift image 3804 can equal the numbers of rows and columns of the ultrasound sensor 3100. In this case, the pixels of the time-shift image can have a one-to-one correspondence with the pixel elements 3110 of the sensor 3100.

[0269]

[0251] In some embodiments, the method 31000 further includes post-processing of the timeshift image (e.g., post-processing of the time-shift image data). For example, post-processing can include applying, to the time-shift image, one or more of: Wiener filtering, steerable filtering, histogram equalization, and / or binarization. In some embodiments, binarization is applied to the fingerprint image 3902 to generate the binarized image 3904. However, any type of image post-processing can be implemented without departing from the scope hereof. Details about various post-processing techniques can be found in Gerard Touma in “A rowcolumn addressed acoustic biometric scanner integrated with pulse oximetry” (Ph.D. Dissertation, Stanford University, 2020).

[0270]

[0252] In some embodiments, the method 31000 includes one or both of the blocks 31008 and 31010. In the block 31008, the baseline echo is identified from a baseline waveform obtained from the ultrasound transducer while the object contacted the platen surface. In the block 31010, the signal echo is identified from a signal waveform obtained from the ultrasound transducer while the object was not contacting the platen surface. The signal echo Docket No. ORC-012-PCT may be an initial echo of the signal waveform, and the baseline echo may be an initial echo of the baseline waveform. The waveform 3500W is one example of a waveform that may be either the signal waveform or the baseline waveform. The sub-waveform 3504 is one example of an initial echo.

[0271]

[0253] In some embodiments, the block 31012 of the method 31000 includes the blocks 31014, 31016, and 31018. In the block 31014, the signal waveform is processed to identify the signal arrival time. In the block 31016, the baseline waveform is processed to identify the baseline arrival time. In the block 31018, the baseline arrival time is subtracted from the signal arrival time to determine the time shift. The signal waveform can be filtered prior to identifying the signal arrival time. Similarly, the baseline waveform can be filtered prior to identifying the baseline arrival time.

[0272]

[0254] The preceding embodiments of the method 31000 can be performed on a computer system (e.g., see the ultrasound signal-processing system 31800 of FIG. 19), such as a computer system that receives signal and baseline waveforms 3500 recorded by the finger sensor system 3700. A third party may operate the finger sensor system 3700 and transmit the recorded waveforms 3500 to the computer system for processing. Thus, the ultrasound sensor is not required to perform the method 31000. However, the following discussion presents additional embodiments of the method 31000 that include operation of the ultrasound sensor to obtain waveforms.

[0273]

[0255] Accordingly, some embodiments of the method 31000 include the blocks 31002 and 31004. In the block 31002, a signal ultrasound pulse is transmitted, by the ultrasound transducer, into the platen such that a portion of the signal ultrasound pulse reflects off of the platen surface to form the signal echo. In the block 31004, the signal echo is sensed with the ultrasound transducer. The output of the ultrasound sensor can then be processed into a signal waveform. For example, in FIG. 8 the amplifier 3402 amplifies the output of the sensor array 3100 into the amplified output 3404, the ADC 3706 digitizes the amplified output 3404 into sensor data 3716, and the real-time processor processes the sensor data 3716 into the waveform 3500W. While the ultrasound transducer in this example is an array of multiple pixel elements, the ultrasound transducer can alternatively be a single ultrasound transducer.

[0274]

[0256] In some embodiments, the ultrasound transducer includes one or more pixel elements of an ultrasound transducer array. In these embodiments, the method 31000 can include the decision block 31006 that repeats the block 31002 and 31004 for each pixel element of the transducer array. If the pixel elements of the transducer array are row-column addressable, then the signal ultrasound pulse can be transmitted, and the signal echo can be sensed, by Docket No. ORC-012-PCT controlling the ultrasound transducer array via row-column addressing. The signal ultrasound pulse can be transmitted using only one row of the sensor array, and the echo pulse can be sensed using only one column of the sensor array. In one example of these embodiments, the column electrode 3108(y) of the ultrasound sensor 3100 is excited to transmit the ultrasound pulse 3118(7) into the platen 3102. The ultrasound pulse 3118(7) reflects off the top surface 3112 of the platen 3102 to generate echoes 3406, 3408 that are then sensed by the row electrode 3106(i).

[0275]

[0257] In other embodiments, the ultrasound transducer array has individually addressable pixel elements. In these embodiments, the signal ultrasound pulse can be transmitted, and the signal echo can be sensed, by addressing the individual pixel elements. In some embodiments, the signal ultrasound pulse can be transmitted using beamforming, i.e., multiple pixel elements can be excited simultaneously, and with appropriately selected complex- valued weights, such that the signal ultrasound pulse is focused onto the top face of the platen. Similarly, the signal echo can be sensed using beamforming, i.e., multiple pixel elements can be sensed simultaneously, and with appropriate complex-values weights applied to the electrical outputs of the pixel elements. Beamforming can be implemented with both row-column addressable sensor arrays and individually addressable sensor arrays. Beamforming can also be realized in software on the detected data once it is digitized and stored in a computer (e.g., see the ultrasound-signal processing system 31800 of FIG. 19), as an alternative to beamforming using hardware for both or either transmit and receive operations.

[0276]

[0258] In the preceding embodiments of the method 31000 that include the blocks 31002 and 31004, baseline waveforms can be stored in memory, and retrieved from the memory, as part of the block 31012. However, in other embodiments, the method 31000 iterates twice over the blocks 31002 and 31004. Specifically, the method 31000 performs a first iteration over the blocks 31002 and 31004 to measure the signal waveform, as described above. In the second iteration over the blocks 31002 and 31004, a baseline ultrasound pulse is transmitted, by the ultrasound transducer, into the platen such that a portion of the baseline ultrasound pulse reflects off of the platen surface to form the baseline echo. The baseline echo is then sensed with the ultrasound transducer. The output of the ultrasound sensor can then be processed into the baseline waveform, similarly to the signal waveform. The baseline waveform can be generated before or after the signal waveform. Docket No. ORC-012-PCT

[0277]

[0259] In embodiments where the ultrasound transducer is a pixel element of an ultrasound transducer array, the method 31000 includes the block 31005 to repeat the blocks 31002 and 31004 for each pixel element of the transducer array. Specifically, the method 31000 performs a first iteration of the blocks 31002, 31004, and 31005 to measure a signal waveform for each pixel element. The method 31000 then performs a second iteration of the blocks 31002, 31004, and 31005 to measure a baseline waveform for each pixel element. The transducer array can be controlled to transmit the baseline ultrasound pulse similarly to how it is controlled to transmit the signal ultrasound pulse (e.g., row-column or individual-pixel addressing, beamforming or single-row transmitting, and the like). Similarly, the transducer array can be used to sense the baseline echo similarly to how it is used to sense the signal echo (e.g., row-column or individual-pixel addressing, beamforming or single-column sensing, and the like). The signal and baseline waveforms can be obtained in any temporal order. For example, all of the signal waveforms can be obtained before all of the baseline waveforms, or vice versa.

[0278] Signal Processing to Determine Time Shifts

[0279]

[0260] FIG. 12 is a flow chart of a method 31100 for processing a waveform to identify an arrival time of an echo. When the method 31100 is performed with the signal waveform to identify the signal arrival time, the method 31100 can substitute for the block 31014 of the method 31000. Similarly, when the method 31100 is performed with the baseline waveform to identify the baseline arrival time, the method 31100 can substitute for the block 31016 of the method 31000.

[0280]

[0261] In the block 31108 of the method 31100, the waveform is processed to identify a zero crossing of the echo. In the block 31110, the arrival time of the echo is calculated based on a time of the zero crossing. The blocks 31108 and 31110 can be performed with the signal waveform to calculate the signal arrival time ta. The blocks 31108 and 31110 can also be

[0281] Ci? performed with the baseline waveform to calculate the baseline arrival timeJ. The signal arrival time can be determined before or after the baseline arrival time is determined.

[0282]

[0262] Some embodiments of the method 31100 include the block 31104, in which a mean of the waveform is subtracted from the waveform to obtain a mean-corrected waveform. In these embodiments, the blocks 31108 and 31110 are performed with the mean-corrected waveform, i.e., the identified zero crossing is a zero crossing of the mean-corrected Docket No. ORC-012-PCT waveform. In some of these embodiments, the method 31100 includes calculating the mean of the waveform.

[0283]

[0263] Some embodiments of the method 31100 include the block 31102, in which a subwaveform of the echo is selected from the waveform. The sub-waveform 3504 of FIG. 6 is one example of a sub-waveform. In this case, the block 31104 is performed with the subwaveform (i.e., the mean of the sub-waveform is subtracted from the sub-waveform) to obtain a mean-corrected sub-waveform. The blocks 31108 and 31110 are then performed with this mean-corrected sub-waveform (i.e., the zero-crossing is a zero-crossing of the mean-corrected sub-waveform). The mean-corrected sub-waveforms 3602 and 3604 of FIG. 7 are examples of a mean-corrected baseline sub-waveform and a mean-corrected signal subwaveform, respectively. In one of these embodiments, the method 31100 includes calculating the mean of the sub-waveform.

[0284]

[0264] Some embodiments of the method 31100 include the block 31106, in which the mean- corrected sub-waveform is interpolated to obtain a best-fit curve. In these embodiments, the blocks 31108 and 31110 are performed with the best-fit curve (i.e., the zero crossing is a zero crossing in the best-fit curve). Either the entire mean-corrected sub-waveform can be interpolated, or a portion thereof. For example, a portion of the mean-corrected subwaveform 3602 near a zero crossing 3610 can be selected for linear interpolation, while other portions (e.g., near the neighboring anti-nodes) are excluded. Excluding these other portions advantageously speeds up interpolation by reducing the amount of data that needs to be processed.

[0285]

[0265] As shown in FIG. 6, the sub-waveform 3504 lasts for several cycles, and therefore forms a sequence of zero crossings. Any one or more of these zero crossings can be used to determine a singular arrival time of the echo. The sequence of zero crossings can include only those zero crossings with a positive slope, only those zero crossings with a negative slope, or both. In some embodiments, a sequence of signal zero crossings is processed to determine the signal arrival time, and a sequence of baseline zero crossings is processed similarly to determine the baseline arrival time. Processing these two sequences similarly ensures that the definition of arrival time is the same for the baseline and signal echoes. For example, in embodiments where only one baseline zero crossing is used to determine the baseline arrival time , and where only one signal zero crossing is used to determine the signal arrival time ta, the position of the baseline zero crossing in the sequence of baseline zero crossings can Docket No. ORC-012-PCT be the same as the position of the signal zero crossing in the sequence of signal zero crossings.

[0286]

[0266] In some embodiments of the method 31000, the signal waveform is processed, in the block 31014, to identify the signal arrival time by applying a Hilbert transform to at least part of the signal waveform (e.g., a portion or all of the signal sub-waveform). The output of the Hilbert transform includes a temporal sequence of instantaneous signal phases that can be processed to identify a signal zero crossing. The signal transmit time can then be calculated based on the time when the signal zero crossing occurred. The same steps can be implemented in the block 31016, but with the baseline waveform instead of the signal waveform, to calculate the baseline arrival time. Any of the techniques described above for the method 31100 can be implemented with the sequence of instantaneous signal phases and the sequence of instantaneous baseline phases, such as selecting a sub-waveform, interpolating, subtracting a mean, and the like.

[0287]

[0267] The Hilbert transform can also output a temporal sequence of envelope values that can also be used to determine an echo arrival time. For example, an extremum can be identified in the sequence of envelope values and the time at which the extremum occurred can be selected as the arrival time. The sequence of envelope values can be interpolated to more precisely identify the time at which the extremum occurred. A sequence of envelope values can be used either with or without the corresponding sequence of instantaneous phase values outputted by the Hilbert transform. Examples of techniques to identify an echo arrival time based on both phase and envelope outputs of a Hilbert transform can be found in Mario Kupnik, Edwin Krasser, and Martin Grbschl, “Absolute Transit Time Detection for Ultrasonic Gas Flowmeters Based on Time and Phase Domain Characteristics” (2007 IEEE Ultrasonics Symposium Proceedings, New York, NY, 2007, pp. 142-145). However, those trained in the art will recognize that there are a host of techniques to use the Hilbert transform to determine the arrival time of echo, any of which can be used without departing from the scope hereof.

[0288]

[0268] In some embodiments of the method 31000, the time shift is determined by transforming the baseline and signal waveforms into a cross-correlation signal and calculating the time shift based on the cross-correlation signal. In these embodiments, the block 31012 can exclude the blocks 31014, 31016, and 31018, as the peak of the crosscorrelation signal will directly indicate the time shift dt without having to separately determine the signal and baseline arrival times. Those trained in the art will recognize that Docket No. ORC-012-PCT there are a host of techniques to use cross-correlation to determine a time shift, any of which can be used without departing from the scope hereof.

[0289]

[0269] FIG. 13 is a flow chart of a method 31200 for processing a waveform to identify an arrival time of an echo. Like the method 31100, the method 31200 can be performed with the signal waveform to identify a signal arrival time, in which case the method 31200 can substitute for the block 31014 of the method 31000. Similarly, the method 31200 can be performed with the baseline waveform to identify a baseline arrival time, in which case the method 31200 can substitute for the block 31016 of the method 31000. The method 31200 is similar to the method 31100 except that arrival times are determined from extrema (i.e., maxima or minima) of sub-waveforms. For clarity in the following discussion, maxima are used for the extrema. However, minima can be used instead without departing from the scope hereof.

[0290]

[0270] In the block 31202 of the method 31200, the waveform is processed to identify a maximum of the echo. In the block 31204, the arrival time of the echo is calculated based on a time of the maximum. The blocks 31202 and 31204 can be performed with the signal waveform to calculate the signal arrival time ta. Similarly, the blocks 31202 and 31204 can

[0291] Ci? also be performed with the baseline waveform to calculate the baseline arrival timeJ. The

[0292] (5 (i? signal arrival time can be determined before or after the baseline arrival time is determined.

[0293]

[0271] Some embodiments of the method 31200 include the block 31102, in which a subwaveform of the echo is selected from the waveform. In these embodiments, the blocks

[0294] 31202 and 31204 are performed with this sub-waveform. The resulting amplitude can be a local maximum of the sub-waveform. Some embodiments of the method 31200 include the block 31106, in which the sub-waveform is interpolated to obtain a best-fit curve. In these embodiments, the blocks 31202 and 31204 are performed with the best-fit curve. Either the entire sub-waveform can be interpolated, or a portion thereof.

[0295]

[0272] As shown in FIG 6, the sub-waveform 3504 lasts for several cycles, and therefore forms a sequence of extrema. Any one or more of these extrema can be used to determine a singular arrival time of the echo. The sequence of extrema can include only maxima, only minima, or both. In some embodiments, a sequence of signal extrema is processed to determine the signal arrival time, and a sequence of baseline extrema is processed similarly to determine the baseline arrival time. Processing these two sequences similarly ensures that the definition of arrival time is the same for the baseline and signal echoes. For example, in Docket No. ORC-012-PCT embodiments where only one baseline maximum is used to determine the baseline arrival time , and where only one signal maximum is used to determine the signal arrival time ta, the position of the baseline maximum in the sequence of baseline extrema can be the same as the position of the signal maximum in the sequence of signal extrema.

[0296]

[0273] FIG. 14 illustrates a method 31300 for processing the signal and baseline waveforms to identify the time shift 4t. Similar to cross-correlation, the method 31300 combines the signal and baseline waveforms to directly determine 4t, as opposed to separately processing the signal and baseline waveforms to determine . Accordingly, the method 31300 can be used for the block 31012 of the method 31000. The method 31300 is based on excitation of a pixel element with several continuous cycles of a single-frequency waveform, also referred to as a “tone burst”. For example, the tone burst can be formed from eight consecutive cycles of a sine wave whose frequency is 150MHz. The tone burst can be unipolar or bipolar. Furthermore, the tone burst can be low-pass filtered to smooth out its envelope. It can be assumed that the echo resulting from the tone burst has the same fixed number of continuous cycles of the center frequency. Specifically, any time shift 41 resulting from an object is constant across the entire echo. In this case, a signal sub-waveform 31304 can be subtracted from a baseline sub-waveform 31302 to obtain a difference waveform 31306. The frequency of the difference waveform 31306 is the same as that of the subwaveforms 31302 and 31304, and the amplitude of the difference waveform 31306 depends on the time shift 41. Accordingly, the difference waveform 31306 can be processed to determine the time shift 4t.

[0297]

[0274] For small values of the time shift 41, the amplitude of the difference waveform 31306 will be smaller than that of the sub-waveforms 31302 and 31304. In this case, the difference waveform 31306 will have a lower SNR than the sub-waveforms 31302 and 31304. This reduced SNR can limit how well the time shift 41 can be determined. One way to preserve SNR is to fit each of the sub-waveforms 31302 and 31304 to a sine wave with variable phase and amplitude (but fixed frequency), and then calculate the difference waveform 31306 from the best-fit sine waves. Other techniques to preserve SNR can be used without departing from the scope hereof.

[0298]

[0275] FIG. 15 illustrates two sampling methods 31402 and 31404 for processing a waveform to identify an arrival time of an echo. In method 31402, an echo comprising a sinusoidal waveform is sampled by system 10 at a sampling rate of 10 samples per each cycle of a sinusoid. System 10 can analyze the collected 10 samples per cycle in order to create an Docket No. ORC-012-PCT estimation of the echo (e.g., an estimation of amplitude and / or phase). In method 31404, an echo (e.g., the same echo as in method 31402) is sampled at 2 samples per each cycle of the sinusoid. System 10, knowing the parameters of the transmitted signal from which the echo is based, can similarly provide an estimation of the echo (e.g., an estimation of amplitude and / or phase). The reduced sampling of method 31404 provides numerous advantages, such as processing speed, data storage and transfer, and other advantages. Similar to the methods 31100 and 31200, the methods 31402 and / or 31404 can be performed with a signal waveform to calculate a signal arrival time ta, in which case the methods 31402 and / or 31404 can be used for the block 31014 of the method 31000. Similarly, the methods 31402 and / or 31404 can be performed with a baseline waveform to calculate a baseline arrival time ta, in which case the methods 31402 and / or 31404 can be used for the block 31016 of the method 31000.

[0299] The signal arrival time tacan be determined before or after the baseline arrival time tais determined.

[0300]

[0276] The methods 31402 and / or 31404 can implement quadrature sampling of sensed echoes, which advantageously reduces the amount of data to be recorded and processed, as compared to uniform sampling. For example, the sub-waveforms 3602, 3604 in FIG. 7 can be uniformly sampled (e.g., by the ADC 3706 of FIG. 8) at a sampling rate of 1.25 Gbps (i.e., 0.8ns between sequentially sampled points). At this sampling rate, approximately eight data points can be sampled for each cycle of waveform whose center frequency f0is 150MHz. However, since the center frequency f0is known, only two data points need to be sampled for each cycle in order to determine the phase. These two data points must be separated in time by one-quarter of the period (i.e., in quadrature), but may occur anywhere within a single cycle. Specifically, consider first and second quadrature data points (tltax) and (t2, <22) recorded from one cycle of a baseline waveform. These two data points constrain the baseline waveform to a sinusoid of the mathematical form y(t) = A cos cos (2nf0t + (pb, where A and the baseline phase (pbcan be determined by solving either ar= A cos cos (2nf0t1+ (pbor a2= A cos cos (2nf0t2+ (pb. This process can be repeated for two quadrature data points from the signal waveform to obtain a signal phase (ps. The resulting time shift is then At = (< >s— (pb / (2 f0), where (psand (pbare in radians and f0is in hertz. Alternatively, the phase shift (ps— (pbcan be used directly to create the time-shift image (e.g., by mapping the phase shift to a corresponding grayscale value of a pixel of the time-shift image). Docket No. ORC-012-PCT

[0301] Exemplary Pseudocode

[0302]

[0277] The following pseudocode is an exemplary implementation of the method 31000 in which the method 31200 is used for each of the blocks 31014 and 31016. Comments are preceded by the symbol “#”.

[0303] # Define constants n_tx = 250 # number of transmitting electrodes n_rx = 250 # number of sensing electrodes wfm_size = 100 # number of data points within each waveform interp_f actor = 25 # interpolation factor fc = 150 MHz # center frequency of the transmitted pulse and sensed echo fs = 1 . 25 GSPS # ADC sampling rate

[0304] Ts = fs x interp_factor # sample period after interpolation

[0305] # Retrieve a three-dimensional (3D) array of baseline waveforms . The first index

[0306] # of the array runs from 1 to n_tx , and identifies one corresponding row of the

[0307] # sensor . The second index of the array runs from 1 to n_rx , and identifies one

[0308] # corresponding column of the sensor . The third index runs from 1 to wfm_size

[0309] # and identifies one data point of each waveform. input_data_baseline = echo_array_baseline (n_tx , n_rx , wfm_size)

[0310] # Retrieve a similar 3D matrix of signal waveforms input_data_signal = echo_array_signal (n_tx , n_rx , wfm_size)

[0311] # Pre-process each waveform to remove the mean . The parameter "3" indicates

[0312] # which dimension of the 3D arrays corresponds to the time of the waveforms . input_data_baseline = mean_removal (input_data_baseline , 3) input_data_signal = mean_removal (input_data_signal , 3)

[0313] # Interpolate each waveform to achieve a sample period « expected time delay input_data_baseline = interpolation (input_data_baseline , interp_f actor) input_data_signal = interpolation (input_data_signal , interp_factor)

[0314] # Bandpass filter each waveform between 120 and 180 MHz . The parameter BW is

[0315] # bandwidth , and the parameter N_order is the filter order . Docket No. ORC-012-PCT

[0316] Input_data_baseline = FIR_filter (input_data_baseline , BW = [120 180 ] MHz , N order = 100 )

[0317] Input_data_signal = FIR_filter (input_data_signal , BW = [120 180 ] MHz , N order = 100 )

[0318] # Process each waveform peak to identify the time at which the waveform peaks

[0319] [max_val_baseline , max_idx_baseline] = max (input_data_baseline (sub_window) , 3) [max_val_signal , max_idx_signal] = max (input_data_signal (sub_window) , 3)

[0320] # Generate a two-dimensional 2D map of the time shifts . Multiply each pixel of

[0321] # the map by lel2 to express results in picoseconds

[0322] Raw_image = (max_idx_signal - max_idx_baseline) x Ts x lel2

[0323] Embodiments with a Single Ultrasonic Transducer

[0324]

[0278] As described hereabove, the method 31000 can be performed with a single ultrasound transducer (e.g., not part of an array of multiple transducers). In this case, the method 31000 can be used to detect the presence of an object contacting the platen surface of the platen. For example, the object may be human tissue, such as the finger 3130, contacting the top surface 3112 of the platen 3102 of FIGS. 2 to 5. The presence of the object can be determined from the time shift, such as by comparing the time shift to a threshold. If the time shift is less than the threshold, the time shift can be assumed to be zero, and therefore the signal and baseline arrival times are the same. In this case, it can be inferred that there is no object contacting the platen. On the other hand, if the time shift is greater than the threshold, it can be inferred that an object was contacting the platen while recording the signal waveform. The threshold can be large enough to ensure that statistical fluctuations of echo arrival times do not lead to erroneous indications of the object’s presence. An indication of the presence of the object can then be outputted.

[0325] Embodiments with Biometric Sensing

[0326]

[0279] The method 31000 can also be used for biometric sensing. For example, in some embodiments the object is a finger and the time-shift image is a fingerprint of the finger. The time-shift image 3804 is one example of a time-shift image of a fingerprint. The method 31000 can further include determining, based on the time-shift image, an area of contact between the finger and the platen surface. The area of contact can be an area of ridges of the Docket No. ORC-012-PCT finger in contact with the platen surface (e.g., see ridges 3316 of the finger 3130 in FIGS. 4 and 5). The method 31000 can further include determining, based on the area of contact, an applied force of the finger and / or other human tissue on the platen surface. The method 31000 can further include (i) repeating said determining the time shift (i.e., the block 31012) and said determining the area of contact to generate a temporal sequence of contact areas, (ii) determining an oscillation period of the temporal sequence of contact areas, and (iii) calculating a pulse rate based on the oscillation period. More details about using two- dimensional ultrasound transducer arrays to measure the area of contact of a finger, and determining a pulse rate therefrom, are described by Gerard Touma in “A row-column addressed acoustic biometric scanner integrated with pulse oximetry” (Ph.D. Dissertation, Stanford University, 2020). This reference also describes how an ultrasound transducer array that is at least partially transparent can be combined with a pulse oximeter.

[0327] Embodiments without Baseline Waveforms

[0328]

[0280] FIG. 16 is a flow chart of an ultrasound signal-processing method 31500 that generates a time-shift image without baseline waveforms. In the block 31502, a time shift is determined between (i) an arrival time of an echo sensed by a pixel element of an ultrasound transducer array, and (ii) a baseline arrival time. Any technique or method described herein to determine an echo arrival time can be used as part of the block 31502. For example, the method 31100 or the method 31200 can be used to determine the arrival time from a waveform recorded from the pixel element. With the block 31504, the method 31500 repeats the block 31502 for each pixel element of the ultrasound sensor array. The echo can be generated by an object contacting a platen surface of a platen (e.g., the top surface 3112 of the platen 3102 in FIGS. 2 to 5). The object can be a finger (e.g., the finger 3130), and / or other human tissue.

[0329]

[0281] In the block 31510, a time-shift image is generated based on the time shifts determined for the pixel element. Similar to the method 31000, the pixels of the time-shift image can have a one-to-one correspondence with the pixel elements of the ultrasound transducer array. The time-shift image can then be outputted. When the object contacting the platen is a finger, the time-shift image can be a fingerprint of the finger.

[0330]

[0282] Unlike the method 31000, where the baseline arrival time was determined separately for each pixel element, the baseline arrival time in the method 31500 is the same for all pixel elements. The baseline arrival time can be calculated based on arrival times of one or more of the pixel elements. For example, the baseline arrival time can be set equal to the arrival time Docket No. ORC-012-PCT of one of the pixel elements. Alternatively, the baseline arrival time can be set equal to the average of the arrival times of all the pixel elements. The baseline arrival time can also be set to zero.

[0331]

[0283] The preceding embodiments of the method 31500 can be performed on a computer system (e.g., see the ultrasound signal-processing system 31800 of FIG. 19) that receives waveforms recorded by a sensor system (e.g., the finger sensor system 3700 of FIG. 8). A third party may operate the sensor system and transmit the recorded waveforms to the computer system, which processes the waveforms to determine the echo arrival times. Thus, the ultrasound transducer array is not required to perform the method 31500. However, in some embodiments the method 31500 includes the blocks 31002, 31004, and 31006, in which the ultrasound transducer array is operated to record one waveform for each pixel element. These waveforms can then be used by the block 31502 to determine the corresponding echo arrival times.

[0332] Object Detection Methods

[0333]

[0284] FIG. 17 is a flow chart of an object detection method 31600 that does not use baseline waveforms. In the block 31602, an arrival time is determined for an echo sensed by a pixel element of an ultrasound transducer array. Any technique or method to determine an echo arrival time (e.g., the method 31100 or the method 31200) can be used as part of the block 31602. With the block 31604, the method 31600 repeats the block 31602 for each pixel element of the ultrasound transducer array. The echo can be generated from the object contacting a platen surface of the platen. The object can be human tissue, such as a finger (e.g., the finger 3130 contacting the top surface 3112 of the platen 3102 in FIGS. 2 to 5).

[0334]

[0285] The method 31600 also includes the block 31606, in which a deviation is calculated based on the arrival time determined for one or more pixel elements (e.g., for each pixel element). This deviation is also referred to as the “arrival-time deviation”. The method 31600 also includes the block 31608, in which the presence of an object is determined based on the arrival-time deviation. The arrival-time deviation can be a standard deviation, variance, median absolute deviation, and / or any other statistical measure of dispersion. In some embodiments, the method 31600 includes the block 31610, in which the arrival -time deviation is compared to a threshold. For example, if the arrival-time deviation is less than a threshold, it can be inferred that no object is contacting the platen surface. However, if the arrival-time deviation is greater than the threshold, it can be inferred that an object is contacting the platen surface. Specifically, the ridges 3316 and valleys 3318 of a finger (e.g., Docket No. ORC-012-PCT a finger and / or other body part) can cause the spread of arrival times to increase noticeably, as compared to the distribution of arrival times without the finger contacting the platen surface.

[0335]

[0286] In some embodiments, the method 31600 includes the block 31612, in which an indication of the presence of the object is outputted. The indication can be binary (i.e., an object is indicated as being present or not present). Alternatively, the indication can be a value indicating a probability that an object is contacting the platen surface. The value can be calculated based on the arrival-time deviation, such that a higher arrival-time deviation results in a higher outputted value that indicates a greater likelihood of the object’s presence on the platen.

[0336]

[0287] The preceding embodiments of the method 31600 can be performed on a computer system (e.g., see the ultrasound signal-processing system 31800 of FIG. 19) that receives waveforms recorded by a sensor system (e.g., the finger sensor system 3700 of FIG. 8). A third party can operate the sensor system and transmit the recorded waveforms to the computer system, which processes the waveforms to determine the echo arrival times. Thus, the ultrasound transducer array is not required to perform the method 31600. However, in some embodiments the method 31600 includes the blocks 31002, 31004, and 31006, in which the ultrasound transducer array is operated to record one waveform for each pixel element. These waveforms can then be used by the block 31602 to determine the corresponding echo arrival times.

[0337]

[0288] FIG. 18 is a flow chart of an object detection method 31700 that is similar to the method 31600 except that it uses baseline waveforms. Therefore, the method 31700 implements baseline time compensation by using the time shift for each pixel element, as opposed to a single echo arrival time. Accordingly, the method 31700 includes the blocks 31012 and 31020 of the method 31000. The method 31700 also includes the block 31406, in which a deviation is calculated based on the time shifts, and the block 31408 in which the presence of an object is determined based on the deviation (e.g., by comparing to a threshold). This deviation is also referred to as the “time-shift deviation”. Similar to the method 31600, in method 31700 the signal echo can be generated from the object contacting a platen surface of the platen. The object can be human tissue, such as a finger (e.g., the finger 3130 contacting the top surface 3112 of the platen 3102 in FIGS. 2 to 5). The method 31700 can also include the block 31412 in which an indication of the presence of the object is outputted. Docket No. ORC-012-PCT

[0338]

[0289] Compared to the method 31600, the method 31700 can advantageously improve the accuracy with which the object’s presence is determined, especially when the deviation of round-trip propagation times across the platen is comparable to, or larger than, the arrivaltime deviation. When no object contacts the platen, each time shift is near zero, and the resulting time-shift deviation can be smaller than the arrival -time deviation. When an object contacts the platen, some pixel elements will have time shifts that are no longer near zero. As a result, the time-shift deviation can increase significantly, especially for a fingerprint where ridges and valleys typically give rise to a wide spread of time shifts. This increase in the timeshift deviation can be significantly greater than the increase in the arrival-time deviation, advantageously helping to distinguish between the case when no object contacts the platen, and the case when an object does contact the platen.

[0339]

[0290] The preceding embodiments of the method 31700 can be performed on a computer system (e.g., see the ultrasound signal-processing system 31800 of FIG. 19) that receives waveforms recorded by a sensor system (e.g., the finger sensor system 3700 of FIG. 8). A third party may operate the sensor system and transmit the recorded waveforms to the computer system, which processes the waveforms to determine the signal and baseline arrival times. Thus, the ultrasound transducer array is not required to perform the method 31700. However, in some embodiments the method 31700 includes the blocks 31002, 31004, and 31006, in which the ultrasound transducer array is operated to record waveforms for each pixel element. In some of these embodiments, the method 31700 repeats the blocks 31002, 31004, and 31006 twice, the first time to obtain signal waveforms and the second time to obtain baseline waveforms. These signal and baseline waveforms can then be used by the block 31012 to determine the time delays.

[0340] System Embodiments

[0341]

[0291] FIG. 19 is a block diagram of an ultrasound signal-processing system 31800 with which the present method embodiments can be implemented. The ultrasound signalprocessing system 31800 is a computer system that can form at least part of an ultrasoundbased sensor system, such as the finger sensor system 3700 of FIG. 8. For example, the ultrasound signal-processing system 31800 can serve as one or both of the computer 3710 and the real-time processor 3708.

[0342]

[0292] The ultrasound signal-processing system 31800 includes a processor 31802 and a memory 31806 that communicate with each other over a system bus 31804. The system 31800 can also include at least one VO block 31812 for communicating with at least one Docket No. ORC-012-PCT peripheral device. While FIG. 19 shows the system 31800 with only one I / O block 31812, the system 31800 can contain any number of the I / O block 31812, as needed to implement the functionality described herein. For example, when the system 31800 serves as the computer 3710, the VO block 31812 can be used to receive waveforms 3500 from the real-time processor 3708. In this case, the I / O block 31812 can be a serial port or parallel port that interfaces with the real-time processor 3708. Similarly, the I / O block 31812 can be a graphics card for outputting time-shift images to a display, display 31803 shown (e.g., a display similar to display 3712 of FIG. 8), or a host adapter that connects the system 31800 to a storage device (e.g., a hard disk drive, solid-state drive, memory card, memory stick, and the like) for storing and retrieving time-shift images and other data. The I / O block 31812 can also be a host adapter that connects the system 31800 to a network for communicating with another device or computer system (e.g., via a wide area network, a local area network, the internet, Wi-Fi, USB, and the like), such as a biometric security system that processes timeshift images to determine access to a room, computer system, files, and the like. In some embodiments, the system 31800 implements at least some of the functionality of the biometric security system. Accordingly, the system 31800 is not limited to implementing only the functionality of the finger sensor system 3700.

[0343]

[0293] The processor 31802 can be any type of circuit capable of performing logic, control, and input / output operations. For example, the processor 31802 can include one or more of a microprocessor with one or more central processing unit (CPU) cores, a graphics processing unit (GPU), a digital signal processor (DSP), an FPGA, a system-on-chip (SoC), and a microcontroller unit (MCU). The processor 31802 can also include a memory controller, bus controller, one or more co-processors, and / or other components that manage data flow between the processor 31802 and other devices communicably coupled to the system bus 31804. In embodiments where the system 31800 implements the functionality of the real-time processor 3708, the processor 31802 includes at least one circuit and / or chip (e.g., integrated circuit) that operates deterministically, as described previously. The processor 31802 can be one example of the processor 3720 of FIG. 8.

[0344]

[0294] The memory 31806 stores machine-readable instructions 31820 that, when executed by the processor 31802, control the system 31800 to implement the functionality and methods described herein (e.g., one or more of the methods 31000 to 31700). The memory 31806 also stores data 31840 used by the processor 31802 when executing the machine-readable instructions 31820. In the example of FIG. 19, the machine-readable instructions 31820 include a time-shift determiner 31822 that determines a time shift 31846 between a signal Docket No. ORC-012-PCT arrival time of a signal echo sensed by an ultrasound transducer, and a baseline arrival time of a baseline echo sensed by the ultrasound transducer. In this case, the time-shift determiner 31822 implements the block 31012 of the method 31000. The memory 31806 can store additional machine-readable instructions 31820 than shown in FIG. 19 without departing from the scope hereof. Similarly, the memory 31806 can store additional data 31840 than shown in FIG. 19 without departing from the scope hereof. The memory 31806 can be one example of the memory 3722 of FIG. 8.

[0345]

[0295] In some embodiments, the time-shift determiner 31822 identifies the signal echo from a signal waveform 31842 obtained from an ultrasound transducer while an object was contacting a platen surface of a platen, thereby implementing the block 31010 of the method 31000. Similarly, the time-shift determiner 31822 can identify the baseline echo from a baseline waveform 31844 obtained from the ultrasound transducer while the object was not contacting the platen surface, thereby implementing the block 31008 of the method 31000. The time-shift determiner 31822 can also implement the block 31014 of the method 31000 by processing the signal waveform 31842 to identify a signal arrival time 31850 of the signal echo, implement the block 31016 of the method 31000 by processing the baseline waveform 31844 to identify a baseline arrival time 31852 of the baseline echo, and implement the block 31018 of the method 31000 by subtracting the baseline arrival time 31852 from the signal arrival time 31850 to obtain the time shift 31846. Each of the waveforms 31842 and 31844 is an example of the waveform 3500W of FIG. 6, the time shift 31846 is an example of the time shift 41 (see FIG. 7), the signal arrival time 31850 is an example of the signal arrival time

[0346] (5 (b ta , and the baseline arrival time 31852 is an example of the baseline arrival time ta.

[0347]

[0296] The machine-readable instructions 31820 can also include an image generator 31824 that determines, for one or more pixel elements (e.g., all the pixel elements) of an ultrasound transducer array, the time shift for said each pixel to generate an array of time shifts. The image generator 31824 can then generate, based on the array of time shifts, a time-shift image 31848. Therefore, the image generator 31824 can implement the blocks 31020 and 31022 of the method 31000. Although not shown in FIG. 19, the memory 31806 can store additional machine-readable instructions 31820 that control the system 31800 to output the time-shift image 31848 (e.g., via the I / O block 31812 to a peripheral device or another computer system). Machine-readable instructions 31820 can include transducer controller 31828 shown, where transducer controller 31828 comprises data that provides instructions for the Docket No. ORC-012-PCT timing of transmissions of energy, and recording of reflected energy (echoes) for each of the pixel elements.

[0348]

[0297] In some embodiments, the system 31800 includes an ADC 31808 that digitizes the amplified output 3404. As shown in FIG. 19, the ADC 31808 can be connected to the bus 31804 such that the sensor data 3716 outputted by the ADC 31808 can be stored in the memory 31806. Alternatively, the sensor data 3716 can be directly transmitted over the bus 31804 to the processor 31802 for time-stamping, thereby converting the sensor data 3716 into a waveform. The ADC 31808 is one example of the ADC 3706 of FIG. 8.

[0349]

[0298] In some embodiments, the system 31800 includes a MUX controller 31810 that outputs one or more digital control lines 31814 to drive the MUX 3702. As shown in FIG. 19, the MUX controller 31810 can be connected to the bus 31804, and therefore the digital control lines 31814 can be controlled by the processor 31802. However, the MUX controller 31810 can be embedded within the processor 31802. In embodiments where the system 31800 implements real-time functionality (e.g., time-stamping, MUX control, ADC sampling, and the like), the system 31800 can further include the time base 3728.

[0350]

[0299] While FIG. 19 shows the system 31800 as a computing device with a von Neumann architecture, in some embodiments system 31800 uses a Harvard architecture, or a modified Harvard architecture. In these embodiments, the machine-readable instructions 31820 can be stored as firmware in a separate memory (e.g., non-volatile flash memory) from the data 31840. Accordingly, the system 31800 can form part of an embedded system that includes one or more of the sensor array 3100, MUX 3702, amplifier 3402, and signal source 3304.

[0351]

[0300] The systems of the present inventive concepts can produce an image (e.g., an image of a fingerprint or other tissue surface) using amplitude-shift image creation or time-shift image creation, each as described herein. In some embodiments, system 10 is configured to use both amplitude-shift image creation, as well as time-shift image creation (e.g., in order to create an enhanced image of a fingerprint or other tissue surface). In these embodiments, system 10 can be configured to utilize beamforming, also as described herein, to further enhance the image quality achieved.

[0352]

[0301] Referring collectively to FIGS. 20 through 28, various configurations of a sensor 100 and system 10 are illustrated, such as ultrasound-based systems and sensors that utilize a multi-platen configuration.

[0353]

[0302] In some embodiments, sensor 100 is constructed and arranged as described in reference to FIGS. 25A-D described herein. Docket No. ORC-012-PCT

[0354]

[0303] The present embodiments can include multi-platen ultrasound sensors (e.g., fingerprint sensors) that utilize two or more platens. These sensors can be used to sense one or more fingerprints. Advantageously, the present embodiments can drive and sense multiple pixel transducers simultaneously, thereby reducing the time needed to scan across a set of multiple pixel transducers and generate a fingerprint image. For example, a set of multiple pixel transducers of a multi-platen sensor with two platens can be operated in approximately half the time required to operate each of the pixel transducers of the set individually. Signals from electrically-paired pixel transducers (e.g., electrically connected sets of two, three, or more pixel transducers) can be distinguished and assigned to the platens using temporal discrimination, frequency discrimination, or a combination thereof. Furthermore, some of the present embodiments feature electrically-paired pixel transducers that share transmit electrodes and receive electrodes. In some embodiments, a multi-platen ultrasound sensor of the present inventive concepts comprises three, four, five, or more platens.

[0355]

[0304] Advantageously, electrically-paired pixel transducers reduce the number of electrical connections to the fingerprint and / or other sensor (“sensor” or “fingerprint sensor” herein), thereby simplifying multiplexing circuitry that interfaces with the sensor. Another advantage of the present embodiments is reduced energy per scan. A portion of the energy consumed by an ultrasound fingerprint sensor system is proportional to the scan time. Such energy is typically consumed by amplifiers and other electronics that are maintained in an “active” state during scanning. Since the present embodiments reduce the scan time, these electronics can spend more time in a lower-energy “sleep” state. Reduced energy per scan can extend battery life, such as when the present embodiments are used for portable electronic devices (e.g., smartphones, laptops, and tablets) in which extended battery life is a significant advantage.

[0356]

[0305] The embodiments of system 10 described herein can tolerate variations in platen topography that typically occur during fabrication. For example, when the platen is a glass display for a smartphone, tablet, or the like, the resulting platen topography can typically depend on the specific processes used to manufacture the display, the size of each display pixel, the overall size of the display, and / or other factors. In any case, pixel elements can be deposited on the rear face of the platen while still achieving all or at least a portion of the above benefits. Thus, while the present embodiments are shown with platens having perfectly flat surfaces, it should be understood that the platen surfaces can have some curvature, surface variations, digs, defects, and / or other topological features (e.g., topological nonuniformities), and that the presence of these topological features will have minimal, if Docket No. ORC-012-PCT any, impact on the manufacture and / or operation (e.g., performance) of the present embodiments.

[0357]

[0306] While the present embodiments are described as fingerprint sensors, the present embodiments can be used to measure any object contacting the two, three, or more platens, provided that the presence of the object induces a measurable shift in the amplitude and / or phase of the echo. Examples of such objects include prosthetics, toes and other human tissue, and inanimate objects. The present embodiments can therefore be used to determine the binary presence of a single object contacting any one of the platens, or an integer number of objects (e.g., multiple fingers, from one or more users) contacting the platens. This ability to detect object presence can be combined with fingerprint sensing. For example, the present embodiments can be programmed to only perform fingerprint sensing after one or more objects contacting the platens (e.g., platens 4102 and 4103 described herein) are detected.

[0358]

[0307] When used for fingerprint sensing, the present embodiments can be integrated with other physical, physiological, and biological measurements as part of a multi -function biometric system. For example, the documents (i) International Publication No. WO 2019 / 032590, titled “Interactive Biometric Touch Scanner”, and (ii) Gerard Touma, “A rowcolumn addressed acoustic biometric scanner integrated with pulse oximetry” (Ph.D. Dissertation, Stanford University, 2020) show how a pulse oximeter can be incorporated with an ultrasound transducer array when at least part of the transducer array is optically transparent (e.g., in the near-infrared). Each of these documents is incorporated herein by reference in its entirety.

[0359]

[0308] As another example of biometric measurements, the present embodiments can be used to determine an area of contact between finger ridges and one of the platens. This area of contact can be measured over time to identify periodic changes indicative of a pulse. In this way, the biometric system can distinguish between living tissue and inanimate matter. The present embodiments can be combined with other sensors and biometric functionality without departing from the scope hereof. Furthermore, multiple biometric functionalities can be implemented with different platens of one fingerprint sensor. For example, one platen can be used for pulse oximetry with one finger while another is used to measure pulse and / or other physiologic parameter of one or more users (“user” herein).

[0360]

[0309] FIG. 20 is a perspective view of a multi-platen ultrasound fingerprint sensor 4100 having a first platen 4102 and a second platen 4103 with different round-trip propagation times. FIG. 21 is a side cross-sectional view of the multi -platen ultrasound fingerprint sensor 4100 of FIG. 20. The fingerprint sensor 4100 also includes a first ultrasound transducer array Docket No. ORC-012-PCT

[0361] 4104 that can be bonded to, and / or fabricated on, a first rear face 4122 of the first platen 4102. An ultrasound pulse emitted by the first ultrasound transducer array 4104 propagates through the first platen 4102 in the +z direction (see the right-handed coordinate system 4120) toward a first front face 4112 of the first platen 4102. The first front face 4112 is a boundary between materials with different mechanical impedances (e.g., different densities and / or stiffnesses). Therefore, the ultrasound pulse will reflect off the first front face 4112, and the resulting reflection will propagate through the first platen 4102 in the -z direction toward the first rear face 4122, where it is detected by the first ultrasound transducer array

[0362] 4104. This reflection is also referred to as an echo.

[0363]

[0310] Similarly, the multi-platen ultrasound fingerprint sensor 4100 also includes a second ultrasound transducer array 4105 that can be bonded to, and / or fabricated on, a second rear face 4123 of the second platen 4103. An ultrasound pulse emitted by the second ultrasound transducer array 4105 propagates through the second platen 4103 in the +z direction toward a second front face 4113 of the second platen 4103. Like the first front face 4112, the second front face 4113 is a boundary between materials with different mechanical impedances, and therefore the ultrasound pulse will reflect off the second front face 4113. The resulting reflection, or echo, will propagate through the second platen 4103 in the -z direction toward the second rear face 4123, where it is detected by the second ultrasound transducer array

[0364] 4105. In some embodiments, faces 4112 and 4113 can be differentiated (e.g., tactically differentiated) by a finger of a user, such that the user can place one or more fingers on a particular surface via the differentiation (e.g., to select one surface versus the other to perform a particular function associated with one surface versus the other).

[0365]

[0311] In FIGS. 20 and 21, the first platen 4102 and second platen 4103 have different round-trip propagation times due to different thicknesses. Specifically, the first platen 4102 has a first thickness d along the z direction while the second platen 4103 has a second thickness d2that is different than the first thickness d . The first thickness d is measured between the first rear face 4122 and the first front face 4112. Similarly, the second thickness d2is measured between the second rear face 4123 and the second front face 4113. While FIGS. 20 and 21 show the first thickness d as being greater than the second thickness d2, the first thickness d can alternatively be less than the second thickness d2. As described in more detail below, in some of the present embodiments the first thickness d is the same as the second thickness d2. Docket No. ORC-012-PCT

[0366]

[0312] A finger or other body tissue, finger 4130 shown, physically contacts the front faces 4112 and 4113, such as to detect a fingerprint. While FIGS. 20 and 21 show the sensor 4100 being used to sense the fingerprint of only one finger 4130, the sensor 4100 can alternatively be used to simultaneously sense more than one finger (e.g., from a single user or from multiple users). For example, a first finger 4130(1) can physically contact the first front face

[0367] 4112 at the same time that a second finger 4130(2) physically contacts the second front face

[0368] 4113 (e.g., see FIGS. 22 and 23). To detect a full fingerprint, each of the platens 4102 and 4103 can have an area (i.e., in the x and y direction) of at least 0.1cm2, 0.3cm2, 0.5cm2, 0.7cm2and / or 1cm2. For clarity, the finger 4130 is not drawn to scale in FIGS. 20 and 21.

[0369]

[0313] The first ultrasound transducer array 4104 has a plurality of first pixel transducers 4110 that, in the example of FIGS. 20 and 21, are arranged in a linear two-dimensional array of rows and columns. Similarly, the second ultrasound transducer array 4105 has a plurality of second pixel transducers 4111 that are also shown as being arranged in a linear two- dimensional array. In FIGS. 20 and 21, the first pixel transducers 4110 are row-column addressable via a plurality of receive electrodes 4108 and a plurality of first transmit electrodes 4106. Similarly, the second pixel transducers 4111 are row-column addressable via the plurality of receive electrodes 4108 and a plurality of second transmit electrodes 4107. Thus, each of the first transmit electrodes 4106 extends in the y direction only across the first platen 4102, each of the second transmit electrodes 4107 extends in the y direction only across the second platen 4103, and each of the receive electrodes 4108 extends in the x direction across both the first platen 4102 and the second platen 4103.

[0370]

[0314] The first ultrasound transducer array 4104 also includes a first piezoelectric layer

[0371] 4114 that is located between the receive electrodes 4108 and the first transmit electrodes 4106. Similarly, the second ultrasound transducer array 4105 includes a second piezoelectric layer 4115 that is located between the receive electrodes 4108 and the second transmit electrodes 4107. Thus, each of the first pixel transducers 4110(j,i) is spatially defined by the overlap, in the x-y plane, of the jthreceive electrode 4108(j) and the Ithfirst transmit electrode 4106(i), while each of the second pixel transducers 4111 ( / ,£) is spatially defined by the overlap, in the x-y plane, of the jthreceive electrode 4108(j) and the ithsecond transmit electrode 4107(i).

[0372]

[0315] For clarity, FIG. 20 only shows nineteen first transmit electrodes 4106, nineteen second transmit electrodes 4107, and seventeen receive electrodes 4108. Similarly, FIG. 21 only shows six first transmit electrodes 4106 and six second transmit electrodes 4107. Docket No. ORC-012-PCT

[0373] However, the sensor 4100 can have any number of first transmit electrodes 4106, any number of second transmit electrodes 4107, and any number of receive electrodes 4108 without departing from the scope hereof. Typically the fingerprint sensor 4100 will contain several hundred first transmit electrodes 4106, several hundred second transmit electrodes 4107, and several hundred receive electrodes 4108. For example, the first ultrasound transducer array 4104 can have 512 first transmit electrodes 4106 and 512 receive electrodes 4108, corresponding to 512 x 512 = 262,144 first pixel transducers 4110. The second ultrasound transducer array 4105 can be similarly configured, yielding a total of 524,288 pixel transducers 4110, 4111.

[0374]

[0316] The first piezoelectric layer 4114 can be electrically actuated (e.g., via an ultrasound wave into the first platen 4102). The piezoelectric layer 4114, when mechanically actuated by an ultrasound wave, produces a time-varying electrical signal that can be subsequently detected and processed. The first piezoelectric layer 4114 can be formed from a crystal (e.g., lithium niobate, lithium tantalate, quartz, and the like), ceramic (e.g., zinc oxide, lead zirconium titanate, potassium niobate, barium titanate, and the like), III-V or II- VI semiconductor (e.g., aluminum nitride, gallium arsenide, and the like), polymer, and / or any other piezoelectric material. Similar materials of construction are applicable for the second piezoelectric layer 4115.

[0375]

[0317] FIG. 20 shows the Ithfirst transmit electrode 4106(i) “emitting” an ultrasound pulse 4116(i) into the first platen 4102 (i.e. the electrode-piezo-electrode transducer element emits an ultrasound pulse). Since each first transmit electrode 4106 extends across the entire length (in the y direction) of the first platen 4102, the ultrasound pulse 4116(i) similarly extends across the entire length of the first platen 4102. FIG. 20 similarly shows the Ithsecond transmit electrode 4107(i) emitting an ultrasound pulse 4117(i) into the second platen 4103. FIG. 20 also shows the receive electrode 4108(j) emitting an ultrasound pulse 4118(j) into both of the platens 4102 and 4103. The receive electrode 4108(j) extends across the entire width (in the x direction) of the fingerprint sensor 4100, and therefore the ultrasound pulse 4118(7) similarly extends across the entire width of both platens 4102 and 4103. While the electrodes 4106 and 4107 are referred to as “transmit” electrodes, it should be understood that these electrodes can alternatively or additionally be used for sensing echoes. Similarly, the electrodes 4108, while referred to herein as “receive” electrodes, can alternatively or additionally be used for emitting ultrasound pulses into the platens 4102 and 4103. Docket No. ORC-012-PCT

[0376]

[0318] FIG. 22 shows the multi -platen ultrasound fingerprint sensor 4100 being electrically driven to simultaneously emit a first ultrasound pulse 4316 into the first platen 4102 and a second ultrasound pulse 4317 into the second platen 4103. FIG. 23 shows the fingerprint sensor 4100 sensing a first echo 4416 generated when the first ultrasound pulse 4316 reflects off the first front face 4112, and a second echo 4417 generated when the second ultrasound pulse 4317 reflects off the second front face 4113. FIGS. 22 and 23 are the same cross- sectional view as FIG. 21, but with a first finger 4130(1) contacting the first front face 4112 and a second finger 4130(2) contacting the second front face 4113. FIGS. 22 and 23 are best viewed together with the following description.

[0377]

[0319] The bottom surface of each of the fingers 4130(1) and 4130(2) forms an alternating sequence of ridges 4320 (also referred to as "friction ridges" or "epidermal ridges") and valleys 4322. Each ridge 4320 of the first finger 4130(1) directly contacts the first front face 4112 of the first platen 4102 while the valleys 4322 do not directly contact the first front face 4112. Thus, beneath each valley 4322, air contacts the first front face 4112. Accordingly, the reflection coefficient at the first front face 4112 is larger at the valleys 4322 and smaller at the ridges 4320, and therefore the amplitude of the echo 4416 is larger when the reflection occurs at a ridge 4320, as opposed to a valley 4322. Similar arguments hold for at the second front face 4113.

[0378]

[0320] In FIG. 22, a waveform generator 4304 outputs a drive signal 4306 to both the first transmit electrode 4106(i) and the second transmit electrode 4107(i), which are electrically connected. All of the other transmit electrodes 4106 and 4107 are grounded and all of the receive electrodes 4108 are grounded. In this configuration, the ultrasound pulses 4316 and 4317 are emitted at similar times (ignoring slight differences in electrical propagation times to the transmit electrodes 4106(i) and 4107(i)). In FIG. 23, the receive electrode 4108(j) outputs a first electrical pulse 4418 in response to sensing the first echo 4416, and a second electrical pulse 4420 in response to sensing the second echo 4417. Both of the electrical pulses 4418, 4420 are outputted on the same electrically conductor, and are both processed by an amplifier 4402 into an amplified output 4404 that is subsequently digitized and processed. For the sensing shown in FIG. 23, all of the transmit electrodes 4106 and 4107 are grounded. Although not shown in FIG. 23, all of the other receive electrodes 4108 are also grounded.

[0379]

[0321] Since the platens 4102 and 4103 have different round-trip propagation times, the electrical pulses 4418 and 4420 are temporally distinguishable, i.e., the electrical pulses 4418 and 4420 can be unambiguously assigned to the echoes 4416 and 4417. Specifically, the first Docket No. ORC-012-PCT round-trip propagation time of the first platen 4102 is tx= 2d1 / v1, where v is the velocity of sound of the first platen 4102. Similarly, the second round-trip propagation time of the second platen 4103 is t2= 2d2 / v2, where v2is the velocity of sound of the second platen 4103. Assuming that the platens 4102 and 4103 are fabricated from the same bulk material = v2), the choice of d < d means that t2< t . Accordingly, the first electrical pulse 4418 is due to the second echo 4417 and the second electrical pulse 4420 is due to the first echo 4416.

[0380]

[0322] The electrical pulses 4418 and 4420 can be partially overlapped (in time) while still being temporally distinguishable. For example, a tail of the first electrical pulse 4418 can overlap ahead of the second electrical pulse 4420 such that the peaks of the electrical pulses 4418 and 4420 are detected at different times. Thus, a delay |t2— t between the peaks of the electrical pulses 4418 and 4420 can be less than the temporal widths of the electrical pulses 4418 and 4420.

[0381]

[0323] In other embodiments, the platens 4102 and 4103 are fabricated from different materials such that #= v2. In these embodiments, the platens 4102 and 4103 can have the same thickness, i.e., d = d2, in which case the platens 4102 and 4103 can be placed at corresponding sides such that the front faces 4112 and 4113 are coplanar, and such that the rear faces 4122 and 4123 are coplanar. In other embodiments, the platens 4102 and 4103 are fabricated from different materials and have different thicknesses.

[0382]

[0324] In other embodiments, the platens 4102 and 4103 form arrays of ultrasound waveguides, as opposed to a bulk material. In these embodiments, one waveguide is located directly over each of the pixel transducers 4110 and 4111. The velocity of the ultrasound pulse (and resulting echo) is determined by a dispersion equation of the waveguide, which typically depends on the geometry of the waveguide (e.g., transverse dimensions), frequency, the sound velocity in the core of the waveguide, and the sound velocity in the material surrounding the core. Accordingly, the first platen 4102 can contain a first array of waveguides sized to achieve a first velocity, while the second platen 4103 contains a second array of waveguides sized to achieve a second velocity different from the first velocity. In this case, the platens 4102 and 4103 can have the same thickness with different round-trip propagation times.

[0383]

[0325] Each of the first pixel transducers 4110 is electrically-paired with one of the second pixel transducers 4111. Specifically, the first pixel transducers 4110 form a one-to-one correspondence with the second pixel transducers 4111. Here, “electrically-paired” means Docket No. ORC-012-PCT that the transmit electrodes of the paired pixel transducers are directly electrically connected to each other, and therefore can be driven by a single waveform generator or oscillator. Similarly, “electrically-paired” also means that the receive electrodes of the paired pixel transducers are directly electrically connected to each other, and therefore their electrical outputs can be processed by a single amplifier and digitized by a single analog-to-digital (A / D) converter or channel.

[0384]

[0326] FIG. 20 shows how a single conductor 4109 is split into two “legs”, one of which is routed to the first transmit electrode 4106(i) while the second is routed to the second transmit electrode 4107(i). In this case, the two legs are electrically in parallel. By contrast, the receive electrode 4108(j) does not need to be split, as it can extend as a single line (either straight, curved, or piece-wise) across both of the platens 4102 and 4103. While FIG. 20 shows only one single conductor 4109 for clarity, it should be understood that every first transmit electrode 4106 is similarly connected to a corresponding second transmit electrode 4107. Furthermore, while FIG. 20 shows the Ithfirst transmit electrode 4106(i) paired with the Ithsecond transmit electrode 4107(i), it is not required that pixel transducers 4110 and

[0385] 4111 be paired in index order (e.g., column 1 electrode does not have to be paired with row 1 electrode).

[0386]

[0327] In other embodiments, the fingerprint sensor 4100 has individually addressable pixel transducers 4110 and 4111. In this case, each of the pixel transducers 4110 and 4111 has its own receive electrode and transmit electrode (i.e., not shared with other pixel transducers in the same row or column), and the above definition of “electrically-paired” still applies.

[0387]

[0328] FIG. 24 is a side cross-sectional view of a multi-platen ultrasound fingerprint sensor 4500 that is similar to the multi-platen ultrasound fingerprint sensor 4100 of FIGS 20 to 23 except that the front faces 4112 and 4113 of FIG. 24 are coplanar. In FIGS 20 to 23, the rear faces 4122 and 4123 of the fingerprint sensor 4100 are coplanar, thereby giving rise to a “step” (in the z direction) between the front faces 4112 and 4113. For the fingerprint sensor 4500 of FIG. 24, this step occurs between the rear faces 4122 and 4123. Therefore, each of the receive electrodes 4108 changes its z position at the step to ensure electrical continuity across both of the platens 4102 and 4103.

[0388]

[0329] The platens 4102 and 4103 can be fabricated from one piece of bulk material (e.g., glass or plastic) to form a single integral component. Alternatively, the platens 4102 and 4103 can be separately fabricated and bonded along corresponding sides (e.g., via contact bonding, epoxy, anodic bonding with an intervening piece of silicon, and the like). In some Docket No. ORC-012-PCT embodiments, the platens 4102 and 4103 can be fabricated using spin on glass (SOG) and / or etching processes. In other embodiments, the first platen 4102 and first transducer array 4104 are physically disjoint from the second platen 4103 and second transducer array 4105. In these embodiments, the first pixel transducers 4110 are electrically-paired with the second pixel transducers 4111 (e.g., via a circuit board to which the transducer arrays 4104 and 4105 are soldered).

[0389]

[0330] The above embodiments (e.g., as described in reference to FIGS. 20 to 23) can use temporal discrimination of the electrical pulses 4418 and 4420 to assign these electrical pulses to first pixel transducers 4110 and second pixel transducers 4111. In other embodiments, the electrical pulses 4418 and 4420 have different frequencies, in which case frequency discrimination can be used to assign these electrical pulses to pixel transducers

[0390] 4110 and 4111. For example, the first pixel transducers 4110 and second pixel transducers

[0391] 4111 can be fabricated with different frequency responses. Specifically, the first pixel transducers 4110 can all have a first resonance with a first center frequency and a first bandwidth. Similarly, the second pixel transducers 4111 can all have a second resonance with a second center frequency, different from the first center frequency, and a second bandwidth. The difference between the first and second center frequencies can be selected to be larger than the first and second bandwidths. In other embodiments, the first and second center frequencies are selected such that there is overlap between the first and second bandwidths, and electrical pulses 4418 and 4420 are differentiated using frequency discrimination as described hereinabove. Electrically-paired pixel transducers 4110 and 4111 can be driven with a two-frequency waveform having a first component at the first center frequency and a second component at the second center frequency. Each of the first and second components can be a tone burst (i.e., an integer number of periods of a single-frequency sinusoidal waveform). The first component will resonantly excite the first pixel transducer 4110(i) at the first center frequency, but without resonant excitation at the second center frequency.

[0392] Conversely, the second component will resonantly excite the second pixel transducer 4111 ( / ) at the second center frequency, but without resonant excitation at the first center frequency. In this case, the ultrasound pulses 4316 and 4317 will have different frequencies, which can be resolved electronically using signal-processing techniques known in the art.

[0393]

[0331] One advantage of frequency discrimination over temporal discrimination is that the platens 4102 and 4103 can be made from a single bulk piece of material of uniform thickness = d2). However, to achieve different frequency responses, the first pixel transducers Docket No. ORC-012-PCT

[0394] 4110 may need to be fabricated separately from the second pixel transducers 4111. The frequency responses can be modified via a thickness of the piezoelectric layers. For example, the first piezoelectric layer 4114 can be fabricated with a different thickness (in the z direction) than that of the second piezoelectric layer 4115. Alternatively or additionally, the shape and thickness of the electrodes 4106, 4107, and 4108 can be modified to alter the frequency responses.

[0395]

[0332] The present embodiments can be used to detect fingerprints or other imageable tissue or other patterns (“fingerprints” herein) by measuring amplitude shifts, e.g., by measuring the spatial variation of amplitude of the echoes. Alternatively or in combination with amplitude shift measurements, the present embodiment can be used to detect fingerprints by measuring time and / or phase shifts, e.g., by measuring the spatial variation of delay time, phase shift, or both. In some embodiments, beamforming techniques can be used to construct the image, for example while using amplitude shift measurements, phase shift measurements, or both. More details about fingerprint detection with time and / or phase shifts is described in U.S. Provisional Patent Application No. 63 / 140,647, filed January 22, 2021, and titled “Ultrasound Signal-Processing System and Associated Methods”. This provisional patent application is incorporated herein by reference in its entirety.

[0396]

[0333] FIG. 25 is a side cross-sectional view of a multi-platen ultrasound fingerprint sensor 4600 in which one array of pixel transducers is used with both the first platen 4102 and the second platen 4103. The fingerprint sensor 4600 is also referred to as a “double-sided” fingerprint sensor in that it can simultaneously detect fingerprints from the first finger 4130(1) and the second finger 4130(2) with the platens arranged in a back-to-back geometry (as opposed to the side-to-side geometry shown in FIGS 20 to 24). The fingerprint sensor 4600 uses temporal discrimination to identify electrical pulses with platens, and therefore d d2when the platens 4102 and 4103 are fabricated from the same bulk material. Given the back-to-back geometry, the fingerprint sensor 4600 is particularly advantageous when one of the fingers 4130(1) and / or 4130(2) is a thumb. Alternatively, the fingerprint sensor 4600 can be used to detect one fingerprint from each of two of a person’s hands (e.g., the finger 4130(1) is from the person’s left hand while the finger 4130(2) is from the person’s right hand), and / or when one finger is from one person and another finger is from another person.

[0397]

[0334] While FIGS. 20 to 24 show the multi-platen ultrasound fingerprint sensors 4100 and 4500 with two platens 4102 and 4103, the concepts of temporal discrimination, frequency discrimination, and electrically-paired pixel transducers can be extended to more than two platens without departing from the scope hereof. For example, a fingerprint sensor similar to Docket No. ORC-012-PCT the fingerprint sensors 4100 and 4500 can be fabricated with three platens of three different thicknesses, and therefore three different round-trip propagation times. In this example, each pixel transducer for the first platen has a corresponding pixel transducer for the second platen and a corresponding pixel transducer for the third platen, giving rise to three pixel transducers forming an electrically connected triad that can be driven simultaneously with one waveform generator. The receive electrode will then output three electrical pulses that are temporally separated, each uniquely corresponding to one of the platens. This concept can be similarly extended to four or more platens.

[0398]

[0335] In other embodiments, a multi-platen ultrasound fingerprint sensor combines time discrimination and frequency discrimination. For example, a fingerprint sensor can comprise four platens. The first and second platens have the same first round-trip propagation time, and the third and fourth platens have the same second round-trip propagation time that is different than the first round-trip propagation time. Furthermore, the first and third platens can be fabricated with pixel transducers having the same first frequency response, while the second and fourth platens can be fabricated with pixel transducers having the same second frequency response that is different than the first frequency response. In this case, the pixel transducers form electrically connected quadruples that can be simultaneously driven with a two- frequency waveform. The sensed echoes then give rise to two temporally distinguishable pulses, each of which contains two resolvable frequencies.

[0399]

[0336] FIGS. 25 A through 25D illustrate various electrical configurations of an ultrasound sensor. Both the double-sided sensor embodiment of FIG. 25 and large area sensor embodiments described herein can be implemented using “Time Division Multiplexing” (e.g., using the time axis in one scan to capture multiple reflections from different locations under the sensor). Alternatively or additionally, “Frequency Division Multiplexing” can be used on the same single time domain signal that provides interrogation at multiple locations under the sensor. These embodiments rely on receiving reflections from several locations under the sensor at different instances in time. These time differences can be accomplished in a variety of ways: different platen thickness at different sensor locations; different platen material at different sensor locations; and / or multiple different sensors (e.g., as with the double-sided sensor). In some embodiments, frequency division multiplexing (FDM) can be achieved by changing the thickness of the piezoelectric (e.g., a zinc oxide piezoelectric) and / or the thickness and / or type of metal layers below and above the piezoelectric. Signal processing of the received signals from different locations can then be applied to extract the amplitude and / or phase of the signals at different locations on the underside of the sensor. Docket No. ORC-012-PCT

[0400]

[0337] As shown in FIG. 25, two fingers (e.g., a thumb and index finger) can be used to apply a compressing force (e.g., a squeeze) to a sensor made of two back-to-back ultrasound sensors, with platens of different thickness, that are attached to have common X-lines (e.g., transmit electrodes) and Y-lines (receive electrodes). Thus, each single X-line (transmit electrode) can be used to transmit two signals, a first signal in a first sensor, and a second signal in a second sensor. The two sensors can be constructed to have platens of slightly different thicknesses, such that the signals on a single Y-line (receive electrode) will arrive at different times (e.g., but on the same electrical connection). The measurement of the amplitudes and / or phases (arrival times) of the two signals would correspond to the fingerprints on the two sensors at the same X-Y location.

[0401]

[0338] The coupling of the two sensors can be accomplished in a variety of ways: such as a solder bump attachment to a flexible printed circuit board thus carrying contacts to the X and Y lines in both sensors.

[0402]

[0339] The two sensors can be of the same or different thickness, and the piezo material (e.g., ZnO film) can be a different thickness such that the phases of the reflected signals would be different, and hence processing of the signals in the frequency domain would allow extraction of the amplitude and phase (arrival time) of the two signals associated with the two fingers, with both arriving on the same electrical channel.

[0403]

[0340] In FIGS. 20-24, a platen with various thicknesses at different sensor locations is shown with the same X-lines and different Y-lines. The Y-lines are connected electrically one by one to have the same channels 1 through n where n is the number of channels. In some embodiments, when exciting one Y-line, ultrasound energy is transmitted from different Y- lines to interrogate the platen at different locations. A receiving X-line would then receive signals on the same channel at different times because of the different thickness of the platen at the different locations. FIGS. 20-24 illustrate two steps (i.e. two different platen thicknesses) in one direction, however there is no limit to the number of steps as long as there is enough separation between the reflected pulses to allow the measurement of the amplitude and phase at different arrival times. In this arrangement, a very large area sensor can be achieved with a relatively low number of channels, thus making data acquisition and processing fast, such as to enable real time operation. Alternatively, this arrangement can be applied to sensors of any size, such as to achieve faster data acquisition.

[0404]

[0341] FIGS. 25A-D illustrate how resources can be shared compared to a single sensor approach. The illustrated hardware can be used to generate images from two or more sensors (essentially multiplying the sensor area) with appropriate connections and time-division Docket No. ORC-012-PCT multiplexing and / or frequency division multiplexing. Time division multiplexing and / or frequency division multiplexing can increase information density without increasing the hardware or the data acquisition time. FIG. 25A illustrates a single 5x5 sensor connected to imaging hardware. Dashed lines represent transmit lines and solid lines represent receive lines. FIG. 25B illustrates two 5x5 sensors connected to the same hardware as FIG. 25A. Dashed lines represent transmit lines. Solid lines represent receive lines with different time of flight (e.g., such as can be achieved with multiple different platen thicknesses as described above) and / or with different frequency responses (e.g., that can be achieved with different ZnO or other piezo material thickness), that can be combined together and can be separated by windowing in the time domain and / or filtering in the digital domain, respectively. FIG. 25C illustrates a variation in the connectivity between sensors.

[0405]

[0342] These arrangements allow for a reduction in the hardware energy requirement per scan (e.g., important for portable applications), since multiple ultrasound channels can share the same electrical channels, and since the total data acquisition time (e.g., the time the hardware needs to be powered) is shorter. A variation of this arrangement can be used which impacts data acquisition time and hardware complexity and reduces digital processing requirements by avoiding time division or frequency division multiplexing. Hardware sharing remains where the transmit electronics and the receive chain, these being the main power drains, are shared.

[0406]

[0343] FIG. 25D illustrates identical 5x5 sensors that are connected to the same transmit lines. On the receiving side, aside from the increased number of multiplexers used to switch between lines, the hardware resources are shared between the two sensors.

[0407]

[0344] Another arrangement for realizing different arrival times of multiple pulses is to use a platen made of different materials that are attached together (e.g., at the side). For instance, multiple glass square rods can be fused together, then sliced horizontally, to make flat disks (e.g., platens) with different material properties (e.g., speed of sound), such as to allow the realization of a large area fingerprint sensor in the manner described earlier. For frequency division multiplexing, system 10 can determine differences in phase in the signals excited at different locations while maintaining the type of electrical connections shown in FIGS. 20- 24, in both X and Y directions. In some embodiments, the change in phase can be accomplished by changing the thickness of the piezo material (e.g., ZnO film).

[0408]

[0345] Applicant has conducted simulations of the above arrangements where output pressure was measured at a fused quartz platen with a piezo ZnO film thickness changing from 16pm to 19pm in 1pm steps. At an operating frequency of 150MHz, there is a phase Docket No. ORC-012-PCT change of about 10° for every micron of ZnO film thickness change. Simulations were performed with arrangements including metal films (e.g., gold with a thickness of 0.2pm) above and below the ZnO film. Sufficient phase shift was present at different locations of the metal films that form the electrode of the sensor. An alternative way to achieve phase shift is by changing the metal over and under the piezoelectric film. A film of aluminum can be used at the interface between the ZnO and the quartz platen. In simulations, a large phase shift is achieved when the thickness of the aluminum film is changed from 0.2pm to 1.0pm.

[0409]

[0346] FIG. 26 is a block diagram of a fingerprint-sensing system 4700 that uses the fingerprint sensor 4100 or 4500. The fingerprint-sensing system 4700 includes a real-time processor 4708 that controls a transmit multiplexer (MUX) 4703 to select which of the electrically-paired transmit electrodes 4106, 4107 is driven by the waveform generator 4304. The real-time processor 4708 also controls a receive MUX 4702 to select which of the receive electrodes 4108 is connected to the input of the amplifier 4402. The amplified output 4404 of the amplifier 4402 is digitized with an analog-to-digital converter (ADC) 4706, whose output is sensor data 4716 that the real-time processor 4708 then time-stamps. The real-time processor 4708 is referenced to a time base 4728 that references all timing. Although not shown in FIG. 26, the time base 4728 can also be used as a time and / or frequency reference for one or both of the ADC 4706 and the waveform generator 4304.

[0410]

[0347] The processor 4708 is “real-time” in that the time it requires to complete an operation is deterministic, and therefore predictable (e.g., does not change based on external factors or unforeseen events). Examples of the real-time processor 4708 include a field-programmable gate array (FPGA), digital signal processor (DSP), and / or a system-on-chip (SoC). However, the real-time processor 4708 can be another type of circuit and / or chip, provided that it operates deterministically.

[0411]

[0348] The real-time processor 4708 transmits the waveform 4500W to a computer 4710 that includes a processor 4720 and a memory 4722 that stores the waveform 4500W. The memory 4722 also stores machine-readable instructions that, when executed by the processor 4720, process the waveform 4500W to determine amplitude shifts and / or time shifts for the sensed pair of pixel transducers 4110, 4111. More details about the signal-processing methods used by the computer 4710 are described in reference to FIGS. 2 through 19 herein.

[0412]

[0349] The fingerprint-sensing system 4700 processes a waveform 4500W for all of the pixel transducers 4110, 4111, from which it generates a fingerprint image. The computer 4710 can display the fingerprint image to a user via a display 4712 that can be integrated with the computer 4710 (e.g., a tablet or laptop computer) or can be separate from the computer 4710 Docket No. ORC-012-PCT

[0413] (e.g., a desktop monitor or high-definition television). Although not shown in FIG. 26, the computer 4710 can alternatively or additionally communicate with another computer system (e.g., via a wide area network, a local area network, the internet, Wi-Fi, and the like) that uses the fingerprint image, such as a biometric security system that processes the fingerprint image to determine access to a room, computer system, files, and the like. In some embodiments, the real-time processor 4708 and computer 4710 are combined as one computer system.

[0414]

[0350] FIG. 27 is a side cross-sectional view of an ultrasound fingerprint sensor 4800 with a wedged platen 4802. The fingerprint sensor 4800 includes an ultrasound transducer array 4804 that is similar to the transducer arrays 4104 and 4105 of FIG. 20, and that is located on a rear face 4822 of the wedged platen 4802. A front face 4812 of the wedged platen 4802 is not parallel to the rear face 4822, and therefore a thickness (in the z direction) of the wedged platen 4802 varies linearly (in the x direction) from to d2. Due to this varying thickness, the round-trip propagation time of an ultrasound pulse emitted by transducer array 4804 will also vary linearly in the x direction.

[0415]

[0351] The ultrasound fingerprint sensor 4800 can be operated similarly to the multi-platen ultrasound fingerprint sensor 4100, and therefore will have similar advantages. Specifically, and as shown in FIG. 27, a pair of transmit electrodes 4106 can be directly electrically connected to each other and driven simultaneously with a single waveform generator 4304. This arrangement will simultaneously emit two ultrasound pulses into the wedged platen 4802, similar to the operation of the multi-platen fingerprint sensor 4100 shown in FIG. 22. Thus, the pixel transducers 4110 in FIG. 27 can be electrically-paired, similar to the electrically-paired pixel transducers described above. Reflections off the front face 4812 will create two echoes that are sensed with a single receive electrode 4108(j), similar to the operation of the fingerprint sensor 4100 shown in FIG. 23. Due to the different round-trip propagation times, each detected echo can be correlated to its spatial location along the x direction.

[0416]

[0352] Advantageously, the ultrasound fingerprint sensor 4800 offers the same benefits as the multi-platen fingerprint sensors described herein, but may be easier to fabricate because the wedged platen 4802 does not have a “step”. While FIG. 27 shows the wedged platen 4802 as sloping only along the x direction, the wedged platen 4802 can be sloped along both x and y directions without departing from the scope hereof.

[0417] Embodiments with Anti-Reflection Coatings Docket No. ORC-012-PCT

[0418]

[0353] FIG. 28 shows two cross-sectional side views of an anti -reflection (AR) coated ultrasound fingerprint sensor 4900. The AR-coated ultrasound fingerprint sensor 4900 has a first AR coating 4902 deposited directly onto the front face 4112 of the platen 4102, which is shown in FIG. 28 as being made of glass. The AR-coated ultrasound fingerprint sensor 4900 has a second AR coating 4904 deposited directly onto the ultrasound transducer array (e.g., transducer array 4104 described herein). Thus, the second AR coating 4904 is deposited directly onto both electrodes (e.g., the electrodes 4106 in FIGS. 20 and 21) and regions of the piezoelectric layer 4114 between the electrodes.

[0419]

[0354] The top diagram in FIG. 28 illustrates probing light 4912 propagating upward (i.e., in the +z direction) through the platen 4102 and into a finger 4130 physically contacting the first AR coating 4902. The probing light 4912 can be generated by a LED or laser (not shown) located underneath the AR-coated ultrasound fingerprint sensor 4900 at a plane 4910. The second AR coating 4904 increases transmission of the probing light 4912 into the piezoelectric layer 4114 (as opposed to the transmission without the second AR coating 4904) by reducing the magnitude of the reflection generated by the step-function change in refractive index between air and the piezoelectric layer 4114 (e.g., ZnO). The first AR coating 4902 increases transmission of the probing light 4912 into the finger 4130 (as opposed to the transmission without the first AR coating 4902) by reducing the magnitude of the reflection generated by the step-function change in refractive index between the platen 4102 and finger 4130.

[0420]

[0355] The bottom diagram in FIG. 28 illustrates signal light 4916 transmitting downward (i.e., in the -z direction) from the finger 4130 and through the platen 4102. The first AR coating 4902 increases transmission of the signal light 4916 out of the finger and into the platen 4102 while the second AR coating 4904 increases transmission of the signal light 4916 out of the piezoelectric layer 4114 and into the underlying air. The signal light 4916, after exiting the piezoelectric layer 4114, can be detected by a photodiode (not shown) located on or near the plane 4910.

[0421]

[0356] The AR-coated ultrasound fingerprint sensor 4900 can be used to increase signal -to- noise ratio (SNR) of a pulse oximeter. The above-referenced documents (i) International Publication No. WO 2019 / 032590 and (ii) Gerard Touma, “A row-column addressed acoustic biometric scanner integrated with pulse oximetry” (Ph.D. Dissertation, Stanford University, 2020) show how a pulse oximeter can be incorporated with an ultrasound transducer array when at least part of the transducer array is optically transparent. For pulse oximetry, the wavelength of the probing light 4912 is typically near 660nm while the wavelength of the Docket No. ORC-012-PCT signal light 4916 is typically near 940nm. In this case, the AR coatings 4902 and 4904 can be configured to enhance transmission at both of these wavelengths.

[0422]

[0357] Since the probing light 4912 and signal light 4916 can propagate simultaneously, the second AR coating 4904 reduces the amount of probing light 4912 that is detected with the signal light 4916, thereby reducing the noise level when detecting the signal light 4916. The first AR coating 4902, by increasing the amount of probing light 4912 entering the finger 4130 and the amount of signal light 4916 exiting the finger 4130, increases the signal level when detecting the signal light 4916.

[0423]

[0358] Each of the AR coatings 4902 and 4904 can be configured to increase transmission (i) at any wavelength in the infrared, optical, or ultraviolet regions of the electromagnetic spectrum, (ii) at a plurality of such wavelengths (e.g., 660nm and 940nm), and / or (iii) over a wavelength range (e.g., 660nm to- 940nm). Each of the AR coatings 4902 and 4904 can be a multi-layer dielectric stack (e.g., formed from alternating layers of SiCh and Ta2Os, or other materials used for dielectric stacks) or a single-layer coating (e.g., MgCh).

[0424]

[0359] When the electrodes are made of metal, the probing light 4912 and signal light 4916 cannot travel through the electrodes. However, the electrodes can be made of an optically transparent, electrically conductive material (e.g., indium tin oxide). When the total area of the piezoelectric layer 4114 covered by electrodes is greater than the corresponding area that is uncovered, the second AR coating 4904 can be designed to maximize transmission of light at the interface between air and the electrode material, as opposed to the interface between air and the piezoelectric material, as this can result in an overall increase in transmission of light through the platen 4102 in both directions. Alternatively, the second AR coating 4904 can be designed to partially (but not maximally) increase transmission of light at the interface between air and the electrode material, and partially (but not maximally) at the interface between air and the piezoelectric material. This alternative design can result in maximal transmission of light, depending on the fraction of the area of the piezoelectric layer 4114 that is covered by electrodes, the refractive indices of the piezoelectric layer 4114 and the electrodes, the wavelengths of the probing light 4912 and signal light 4916, and / or other factors.

[0425]

[0360] The AR coatings 4902 and 4904 can be used for an ultrasound fingerprint sensor having a single platen, such as those described in (i) International Publication No. WO 2019 / 032590 and (ii) Gerard Touma, “A row-column addressed acoustic biometric scanner integrated with pulse oximetry” (Ph.D. Dissertation, Stanford University, 2020). The AR coatings 4902 and 4904 can also be used with any one or more of the platens of any of the Docket No. ORC-012-PCT multi -platen ultrasound fingerprint sensors described herein (e.g., the first platen 4102 and second platen 4103 of the multi-platen ultrasound fingerprint sensor 4100 of FIGS. 20 and 21).

[0426]

[0361] In other embodiments, a screen protector for a mobile device with a touch screen (e.g., a smartphone or tablet) includes a thin sheet of plastic (e.g., polyethylene terephthalate or thermoplastic polyurethane), glass, and / or another optically transparent material. A first side of the screen protector directly contacts an outward-facing surface of the touch screen (i.e., the side of the touch screen to be viewed by a user) to physically protect the outwardfacing surface. Deposited directly onto a second side of the screen protector, opposite the first side, can be an AR coating similar to the second AR coating 4904 of FIG. 28. A light source and photodetector for pulse oximetry can be located behind an inward-facing surface of the touch screen, opposite the outward-facing surface, and pointing toward the touch screen. In this case, the touch screen acts like the platen 4102, and the AR coating on the second side increases transmission of light between the screen protector and a finger in direct physical contact with the AR coating. The AR coating can be designed to increase transmission of light used for pulse oximetry (e.g., 660nm and 940nm).

[0427]

[0362] Referring now to FIG. 29, a block diagram of hardware and software portions of a system of the present inventive concepts is illustrated. System 10 includes sensor 100 and controller 200. Sensor 100 and controller 200 can include various components such as those shown in FIG. 29. FIG. 29 illustrates the architectural partitioning between software components (left side) and hardware components (right side). System 10 includes sensor 100 and controller 200 as well as various processing, interface, and power management components. As illustrated, data flow paths are indicated by single arrows while power distribution paths are indicated by double arrows. The software components of system 10 can include a graphical user interface (e.g., an optional GUI that can be displayed on display 3712 of system 10 described herein), and a data and image processing module (e.g., a module comprising software configured to generate a fingerprint image, as described herein.

[0428] Software of system 10 can comprise machine-readable instructions, such as instructions 31820 described herein. The hardware of system 10 (e.g., hardware components of controller 200) can comprise a processing unit, such as processor 31802, configured to execute the instructions of the software of system 10. Controller 200 can include one or more hardware modules selected from the group consisting of a data and / or power interface module; a signal controller module; a signal source module; a power management module; a switching Docket No. ORC-012-PCT module; a receive amplifier module; an ADC module; a data buffer module; and combinations of these. Controller 200 can operably connect to sensor 100 as described herein. The power management module can be configured to provide regulated power to the various hardware components of system 10. The power management module can include voltage regulators, power switches, and / or other control circuitry. The power management module can be configured to provide appropriate voltages and / or currents to one or more components of controller 200. In some embodiments, the power management module is configured to implement multiple power modes. For example, during active fingerprint acquisition, the power management module can provide full power to all components (e.g., active mode). During periods where the system is monitoring for finger-on-detection, the power management module can place some components in a low-power or sleep mode to reduce power consumption. The power management module can be configured to receive one or more control signals to switch between power modes based on operational state.

[0429]

[0363] In some embodiments, system 10 is configured to perform one or more calibration procedures, such as one or more self-calibration procedures. A calibration procedure can be performed during manufacturing (e.g., factory calibration), during initial setup (e.g., user calibration), and / or periodically during use (e.g., runtime calibration). A calibration procedure can determine and store one or more operating parameters selected from the group consisting of operating frequency (which can be determined by performing a frequency sweep); baseline data (baseline waveforms and / or baseline arrival times); beamforming matrices (which can be optimized during perturbation methods); gain correction factors for one or more signal channels; threshold values for finger-on-detection; temperature compensation coefficients; other parameters affecting system performance; and combinations of these.

[0430]

[0364] In some embodiments, system 10 is configured to determine an optimal operating frequency by performing a frequency sweep. The frequency sweep can comprise transmitting ultrasound pulses at multiple different frequencies within a frequency range and measuring one or more performance metrics (e.g., signal amplitude, SNR, image contrast, image resolution) at each frequency. In some embodiments, the frequency ranges tested can include frequencies from 1MHz to 1000MHz, such as a sweep from 10MHz to 50MHz in steps of 1MHz. System 10 can be configured to select the operating frequency that maximizes the performance metric (e.g., or a weighted combination of multiple performance metrics). The optimal operating frequency can vary from sensor to sensor due to manufacturing variations in piezoelectric layer thickness, platen thickness, electrode Docket No. ORC-012-PCT geometry, and / or bonding quality. In some embodiments, the calibration procedure comprises: (1) performing a frequency sweep to determine the optimal operating frequency; (2) acquiring baseline data with no object contacting the platen surface of sensor 100; (3) measuring signal amplitude for each transmit-receive channel pair and calculating gain correction factors to normalize channel responses; (4) optimizing beamforming matrices using perturbation methods (e.g., phase perturbation and / or amplitude perturbation); and (5) determine the threshold values for finger-on-detection using known test conditions (e.g., no object, finger, water, fabric). The calibrated parameters can be stored in memory for use during subsequent imaging operations.

[0431]

[0365] In some embodiments, the calibration procedure comprises acquiring, storing, and utilizing baseline data corresponding to different temperature values. Temperature can affect one or more signal characteristics of system 10, including but not limited to, acoustic velocity, time-of-flight, phase, amplitude, and waveform shape. Accordingly, system 10 can be configured such that baseline data is acquired at a plurality of temperatures and stored in memory. During operation, baseline data corresponding to a temperature that substantially matches the temperature of a target (e.g., a finger) and / or of sensor 100 can be selected and used for signal processing and / or image generation. In this manner, baseline and target data can be temperature-matched to reduce temperature-induced artifacts and improve imaging accuracy.

[0432]

[0366] In some embodiments, baseline data is acquired at multiple discrete temperatures over a temperature range, such as from approximately 15°C to approximately 45°C, including intermediate temperatures (e.g., in increments of 1°C, 2°C, or 5°C). The baseline data acquired at each temperature can include one or more of baseline waveforms, baseline arrival times, channel responses, gain correction factors, and / or beamforming parameters. The stored baseline data can be organized as a lookup table and / or database indexed by temperature. During a fingerprint acquisition, system 10 can select baseline data corresponding to a temperature value that matches or most closely approximates the temperature associated with the target and / or sensor.

[0433]

[0367] In some embodiments, temperature compensation is performed using a combination of baseline data acquired at a single temperature and one or more temperature compensation parameters. For example, baseline data can be acquired at an ambient temperature and stored in memory, and software of system 10 can apply temperature compensation coefficients to modify the baseline data to correspond to a target temperature. The temperature compensation coefficients can account for temperature-dependent variations in acoustic Docket No. ORC-012-PCT propagation, including changes in speed of sound and timing offsets. Such coefficients can be determined during calibration and applied dynamically during operation based on an estimated or measured target temperature.

[0434]

[0368] In some embodiments, the temperature associated with the target is determined using a temperature sensor positioned proximate to sensor 100, such as a thermistor, diode-based temperature sensor, or other temperature-sensing element (e.g., functional element 199 and / or 599 comprising a temperature sensor). The measured temperature can be used by system 10 to select baseline data corresponding to the measured temperature and / or to determine appropriate temperature compensation coefficients. In some embodiments, the temperature sensor is integrated with sensor 100 and / or user device 500 (not shown but described herein), while in other embodiments, the temperature sensor is provided as a separate component (e.g., a separate component of system 10, such as functional element 99).

[0435]

[0369] In some embodiments, system 10 determines the temperature associated with the target without the use of a dedicated temperature sensor. For example, software of system 10 can be configured to analyze one or more characteristics of received RF waveforms that vary with temperature. In some embodiments, a received target waveform is cross-correlated with a plurality of stored baseline waveforms acquired at different temperatures. The baseline waveform exhibiting the highest correlation with the target waveform can be selected as the temperature-matched baseline. The selected baseline data can then be used for further signal processing, imaging, and / or fingerprint feature extraction.

[0436]

[0370] The temperature-matched baseline selection techniques described herein can be used alone or in combination with temperature compensation coefficients. For example, system 10 can first select baseline data corresponding to a closest matching temperature and then apply fine temperature compensation adjustments to further align baseline and target data. These approaches can reduce temperature-induced mismatch between baseline and target data, thereby improving signal consistency, image quality, and fingerprint recognition performance.

[0437]

[0371] Referring now to FIG. 30, and FIGS. 31A through 31D, a graph of IQ values, averaging equations, and a set of four images of phantoms that were processed using averaged IQ data are illustrated, respectively, consistent with the present inventive concepts. Imaging and data processing techniques described in reference to FIG. 30 and FIGS. 31 A through 3 ID can be performed using system 10 described in reference to FIG. 1 and otherwise herein. Docket No. ORC-012-PCT

[0438]

[0372] In some embodiments, sensor 100 of system 10 is operated under varying conditions, such as conditions which expose sensor 100 to varying conditions, such as manufacturing process variations, noise variations, and temperature variations. System 10 can be configured to compensate for undesired effects of varying conditions, such as by implementing techniques to increase signal-to-noise (SNR), as described herein.

[0439]

[0373] Cycle-to-cycle / IQ averaging can be included, such as to improve SNR while maintaining fast scanning speeds. Amplitude noise and phase noise (e.g., due to jitter) are often the limiting factors for echo signal SNR, and therefore the image quality. RF averaging can be used to increase SNR. This process includes averaging multiple RF signals from the same Tx-Rx location, which increases the signal by a factor of N, and increases the noise by a factor of N, effectively increasing the SNR by a factor of N. However, RF averaging requires acquiring the same imaging frame multiple (N) times, which can significantly reduce scan times (increasing imaging throughput). Both SNR and scan time are key performance targets that are inversely correlated. In some embodiments, IQ averaging is used as a method to increase SNR without changing scan time. Since sensor 100 can be driven with a burst of multiple cycles (e.g., 5-10), and since all the different cycles in the echo signal should contain the same information, averaging can be performed across those cycles and increase SNR. If IQ sampling is used, the averaging, “IQ averaging” herein, can be configured where each cycle contains 4 data points: I, Q, -I, and -Q. IQ averaging can comprise averaging the I and the Q components separately. For example, in a 10 cycle burst, the I sample can be averaged 20 times (2 in each cycle), and the Q sample 20 times. Compared to 20 RF averages, this arrangement provides a 20x faster scan time. Similar to any signal averaging method, the performance of cycle-to-cycle or IQ averaging is dependent on how correlated are the samples used for averaging. FIGS. 31 A through 3 ID show examples of images processed with increasing IQ pairs correlating to an increased SNR. If the samples are totally uncorrelated, the SNR improves by a factor of (2N), where N is the number of cycles. If the samples are perfectly correlated, the SNR does not improve, since both signal and noise increase by a factor of 2N. And, if the samples are partially correlated, then the SNR improvement will be between 1 and (2N). FIGS. 31 A-D show test images and SNR analysis performed by applicant using a Ronchi target, which demonstrates the SNR improvement due to IQ averaging.

[0440]

[0374] FIG. 30 illustrates an IQ averaging method. FIG. 30 shows the I and Q samples (circled) on the RF waveform. Docket No. ORC-012-PCT

[0441]

[0375] In some embodiments, system 10 is configured to reduce the impact of Tx voltage ripple. Ripple voltage on top of a transmit pulse burst is considered as amplitude noise if it is not synchronized with the transmit pulse, and will impact image quality. To minimize the impact of voltage ripple on Tx burst, the ripple source can be synchronized to the Tx pulse, which then allows filtering this noise. In some embodiments, the noise of a recorded signal (e.g., amplitude noise or phase noise) can have a random component and / or a deterministic component. Since images generated by system 10 are reconstructed using both amplitude and phase data (IQ), reducing the noise of the recorded signal can directly impact the image quality, and the requirements needed from the ASIC and the system overall. In some embodiments, system 10 can be configured to identify the deterministic component in the amplitude noise and / or phase noise, and to suppress and / or reduce this component in hardware and / or software. In some embodiments, the deterministic component of the noise of a signal can be significantly larger than the random component of the noise. One example of deterministic amplitude noise is ripple on the Tx voltage. In some embodiments, system 10 is configured to suppress ripple noise on the Tx voltage by synchronizing the Tx pulse with the ripple source (e.g., synchronizing the Tx pulse and ripple source in hardware), which can allo...

Claims

Docket No. ORC-012-PCTWHAT IS CLAIMED IS:

1. A user classification system comprising: a sensor configured to produce a sensor signal, the sensor comprising: a controller configured to: provide drive signals to be transmitted by the sensor as ultrasonic pulses; and receive and process signals recorded by the sensor, wherein the signals recorded by the sensor comprise one or more recorded reflections of the ultrasonic pulses transmitted by the sensor; and a user device, wherein the system is configured to classify a user of the user device based on the sensor signal.

2. The system according to claim 1 and / or any one or more other claims herein, wherein the system comprises electronic hardware, and wherein the electronic hardware is configured to perform IQ sampling.

3. The system according to claim 1 and / or any one or more other claims herein, wherein the system is configured to operate at an operating frequency, and wherein the operating frequency is determined based on a sweep of the frequency range.

4. The system according to claim 1 and / or any one or more other claims herein, wherein the sensor is configured based on a set of operating parameters, and wherein a sensor calibration procedure is performed to determine the set of operating parameters.

5. The system according to claim 1 and / or any one or more other claims herein, wherein the system is configured to perform IQ averaging.Docket No. ORC-012-PCT6. The system according to claim 5 and / or any one or more other claims herein, wherein the IQ averaging is configured to increase SNR without increasing scan time.

7. The system according to claim 1 and / or any one or more other claims herein, wherein the sensor comprises an imaging resolution and a set of ultrasound transducers with a physical pitch that is less than the imaging resolution.

8. The system according to claim 1 and / or any one or more other claims herein, wherein the system is configured to detect the presence of a finger of the user based on a signal amplitude and phase of a signal produced by the sensor.

9. The system according to claim 1 and / or any one or more other claims herein, wherein the system is configured to perform image reconstruction using geometric focusing.

10. The system according to claim 1 and / or any one or more other claims herein, wherein the system is configured to perform image reconstruction using a perturbation method.

11. The system according to claim 10 and / or any one or more other claims herein, wherein the perturbation method comprises a phase perturbation method, an amplitude perturbation method, or both.

Images