Ultrasound fingerprint sensor technology and methods for bidirectional fingerprint sensing related applications

Abstract

The present disclosure provides apparatuses, systems, and methods for ultrasonic fingerprint sensors that are capable of detecting fingerprints from opposite sides of an apparatus, such as a smartphone having screens on both sides of a housing. Some implementations of such sensors can include, for example, two piezoelectric and sensor pixel layer assemblies coupled to a common controller. Other implementations of such sensors can include, for example, a single piezoelectric and sensor pixel assembly coupled with a controller configured to apply a distance gate delay to obtain a fingerprint scan from either opposite side of the apparatus. Yet further implementations of such sensors can include an acoustic masking layer to spatially filter ultrasonic waves that propagate to either side of the apparatus.

Description

[0001] Related applications

[0002] The PCT request is filed together with this specification as part of this application. Each application claiming a benefit or priority as identified in the concurrently filed PCT request is incorporated herein by reference in its entirety and for all purposes. Technical Field

[0003] This disclosure relates in its entirety to fingerprint sensor devices and related methods, including but not limited to ultrasonic fingerprint sensor systems and methods for using such systems. Background Technology

[0004] Biometric authentication can be an important feature used to control access to devices, etc. Many existing products include some type of biometric authentication. While some existing biometric authentication technologies provide satisfactory performance under certain conditions, improvements in methods and devices are still desired. Summary of the Invention

[0005] The systems, methods, and apparatus disclosed herein each have several innovative aspects, and no single aspect is solely responsible for the desired properties disclosed herein.

[0006] The various innovative aspects of this subject matter can be implemented in a variety of ways, including as an apparatus or system, a method, or as a non-transitory computer-readable medium storing computer-executable instructions. Various exemplary embodiments are set forth below, although it will be apparent from this disclosure that other embodiments besides those listed below are also within the scope of this disclosure.

[0007] In some specific embodiments, an apparatus may be provided, comprising: a first sensor pixel layer including a plurality of first sensor pixels; a first acoustic masking layer; a first piezoelectric layer; a second acoustic masking layer; and a second sensor pixel layer including a plurality of second sensor pixels. In such an apparatus, the first sensor pixel layer, the first acoustic masking layer, the first piezoelectric layer, the second acoustic masking layer, and the second sensor pixel layer may be arranged in a stacked configuration along a first axis. The first acoustic masking layer may include a first high acoustic impedance (HAI) region and a first low acoustic impedance (LAI) region repeating a first pattern. The second acoustic masking layer may include a second HAI region and a second LAI region repeating a second pattern. The first HAI region may have a higher acoustic impedance than the first LAI region, and the second HAI region may have a higher acoustic impedance than the second LAI region. When viewed along the first axis, the first HAI region may cover the second LAI region, the second HAI region may cover the first LAI region, the first LAI region may cover the second HAI region, and the second LAI region may cover the first HAI region.

[0008] In some specific embodiments of the device, when viewed along the first axis, the first LAI region can be completely covered by the second HAI region, and when viewed along the first axis, the second LAI region can be completely covered by the first HAI region.

[0009] In some specific embodiments of the device, when viewed along the first axis, each first LAI region may occupy a smaller area than the second HAI region that completely covers it, and when viewed along the first axis, each second LAI region may occupy a smaller area than the first HAI region that completely covers it.

[0010] In some specific embodiments of the device, two first reference planes perpendicular to the first axis and spaced apart by a first distance along the first axis can be defined by opposing surfaces of the first LAI region, the first HAI region can be provided by a first gap positioned between the first reference planes, and the first gap may not contain any solid or liquid material.

[0011] In some specific embodiments of the device, the first LAI region may not have a first gap.

[0012] In some specific embodiments of the device, two second reference planes perpendicular to the first axis and spaced apart by a second distance along the first axis may be defined by opposing surfaces of the second LAI region, and the second HAI region may be provided by a second gap positioned between the second reference planes.

[0013] In some specific embodiments of the device, the second LAI region may not have a second gap.

[0014] In some specific embodiments of the device, two second reference planes perpendicular to the first axis and spaced apart by a second distance along the first axis may be defined by opposing surfaces of the second LAI region, the second HAI region may be provided by a second gap positioned between the second reference planes, and the second LAI region may not have a second gap.

[0015] In some specific embodiments of the device, both the first pattern and the second pattern can be a chessboard pattern.

[0016] In some embodiments of the device, each first LAI region may include a continuous material between the first reference planes. In some embodiments of the device, the continuous material may include copper or aluminum.

[0017] In some embodiments of the device, each first LAI region may include a continuous material between the first reference planes, and each second LAI region may include a continuous material between the second reference planes. In some embodiments of the device, the continuous material may include copper or aluminum.

[0018] In some specific embodiments of the device, a first LAI region of the first acoustic masking layer can provide a first conductive path between the first sensor pixel layer and the first piezoelectric layer, and a second LAI region of the second acoustic masking layer can provide a second conductive path between the second sensor pixel layer and the first piezoelectric layer. Each of the first sensor pixels can include circuitry configured to electrically switch its associated first conductive path to switch between acting as a sensor pixel electrode and acting as a first ultrasonic generator electrode. Each of the second sensor pixels can also include circuitry configured to electrically switch its associated second conductive path to switch between acting as a sensor pixel electrode and acting as a second ultrasonic generator electrode.

[0019] In some specific embodiments of the device, each of the first LAI region and the second LAI region may be electrically coupled to an electrode extension region extending into an adjacent one of the first HAI region and the second HAI region, and each electrode extension region may provide a conductive path between the first piezoelectric layer and the first or second LAI region electrically coupled to the first piezoelectric layer.

[0020] In some specific embodiments of the device, the device may further include a second piezoelectric layer, a third piezoelectric layer, a first sensor electrode layer, and a second sensor electrode layer. In such embodiments, the first piezoelectric layer may be interposed between the first sensor electrode layer and the second sensor electrode layer, the second piezoelectric layer may be interposed between the first sensor pixel layer and the first sensor electrode layer, and the third piezoelectric layer may be interposed between the second sensor pixel layer and the second sensor electrode layer. The first sensor pixel layer and the first sensor electrode layer may be configured such that the first sensor pixel measures the charge generated in the second piezoelectric layer in response to ultrasonic waves passing through it, and the second sensor pixel layer and the second sensor electrode layer may be configured such that the second sensor pixel measures the charge generated in the third piezoelectric layer in response to ultrasonic waves passing through it.

[0021] In some specific embodiments of the device, the device may further include a first ultrasonic generator electrode and a second ultrasonic generator electrode. In such embodiments, a first piezoelectric layer may be interposed between the first ultrasonic generator electrode and the second ultrasonic generator electrode, and the first ultrasonic generator electrode, the second ultrasonic generator electrode, and the first piezoelectric layer may be configured such that ultrasonic waves are generated by the first piezoelectric layer in response to an applied potential across the first ultrasonic generator electrode and the second ultrasonic generator electrode.

[0022] In some specific embodiments of the device, a first acoustic masking layer can be inserted between a first sensor electrode layer and a first piezoelectric layer, and a second acoustic masking layer can be inserted between a second sensor electrode layer and a first piezoelectric layer. The first acoustic masking layer can form a conductive path between the first sensor electrode layer and the first piezoelectric layer, and the second acoustic masking layer can form a conductive path between the second sensor electrode layer and the first piezoelectric layer.

[0023] In some specific embodiments of the device, a first acoustic masking layer may be inserted between a first sensor electrode layer and a second piezoelectric layer, a second acoustic masking layer may be inserted between a second sensor electrode layer and a third piezoelectric layer, the first acoustic masking layer may form a conductive path between the first sensor electrode layer and the second piezoelectric layer, and the second acoustic masking layer may form a conductive path between the second sensor electrode layer and the third piezoelectric layer.

[0024] In some specific embodiments of the device, the device may further include a first display layer, a second display layer, a first cover glass, and a second cover glass. In such embodiments, the first display layer may be inserted between the first cover glass and the first sensor pixel layer, the second display layer may be inserted between the second cover glass and the second sensor pixel layer, and both the first display layer and the second display layer may be inserted between the first cover glass and the second cover glass.

[0025] In some specific embodiments of the device, the device may be a mobile communication device.

[0026] In some specific embodiments, a method may be provided, comprising: causing an ultrasonic wave to be generated by a first piezoelectric layer of the device; causing a first ultrasonic wave to pass through a first acoustic masking layer of the device and propagate toward a first side of the device; causing a second ultrasonic wave to pass through a second acoustic masking layer of the device and propagate toward a second side of the device opposite to the first side of the device; causing a first sensor pixel in a first sensor pixel layer of the device to acquire first fingerprint scan data based on reflection of the first ultrasonic wave from the first side of the device; and causing a second sensor pixel in a second sensor pixel layer of the device to acquire second fingerprint scan data based on reflection of the second ultrasonic wave from the second side of the device. In such a specific embodiment, the first sensor pixel layer, the first acoustic masking layer, the first piezoelectric layer, the second acoustic masking layer, and the second sensor pixel layer can be arranged in a stacked configuration along a first axis. The first acoustic masking layer may include a first high acoustic impedance (HAI) region and a first low acoustic impedance (LAI) region that repeat a first pattern. The second acoustic masking layer may include a second HAI region and a second LAI region that repeat a second pattern. The first HAI region may have a higher acoustic impedance than the first LAI region, and the second HAI region may have a higher acoustic impedance than the second LAI region. When viewed along the first axis, the first HAI region may cover the second LAI region, the second HAI region may cover the first LAI region, the first LAI region may cover the second HAI region, and the second LAI region may cover the first HAI region.

[0027] In some specific embodiments of the method, when viewed along the first axis, the first LAI region can be completely covered by the second HAI region, and when viewed along the first axis, the second LAI region can be completely covered by the first HAI region.

[0028] In some specific embodiments of the method, when viewed along the first axis, each first LAI region may occupy a smaller area than the second HAI region that completely covers it, and when viewed along the first axis, each second LAI region may occupy a smaller area than the first HAI region that completely covers it.

[0029] In some specific embodiments of the method, two first reference planes perpendicular to the first axis and spaced apart by a first distance along the first axis may be defined by opposing surfaces of the first LAI region, the first HAI region may be provided by a first gap positioned between the first reference planes, and the first gap may not contain any solid or liquid material.

[0030] In some specific implementations of this method, the first LAI region may not have a first gap.

[0031] In some specific embodiments of the method, two second reference planes perpendicular to the first axis and spaced apart by a second distance along the first axis may be defined by opposing surfaces of the second LAI region, and the second HAI region may be provided by a second gap positioned between the second reference planes.

[0032] In some specific implementations of this method, the second LAI region may not have a second gap.

[0033] In some specific embodiments of the method, two second reference planes perpendicular to the first axis and spaced apart by a second distance along the first axis may be defined by opposing surfaces of the second LAI region, the second HAI region may be provided by a second gap positioned between the second reference planes, and the second LAI region may not have a second gap.

[0034] In some specific embodiments of this method, both the first pattern and the second pattern can be a chessboard pattern.

[0035] In some embodiments of this method, each first LAI region may include a continuous material between the first reference planes. In some such embodiments, the continuous material may include copper or aluminum.

[0036] In some embodiments of this method, each first LAI region may include a continuous material between the first reference planes, and each second LAI region may include a continuous material between the second reference planes. In some such embodiments, the continuous material may include copper or aluminum.

[0037] In some specific embodiments of the method, a first LAI region of the first acoustic masking layer may provide a first conductive path between the first sensor pixel layer and the first piezoelectric layer, and a second LAI region of the second acoustic masking layer may provide a second conductive path between the second sensor pixel layer and the first piezoelectric layer. Each of the first sensor pixels may include circuitry configured to electrically switch its associated first conductive path to switch between acting as a sensor pixel electrode and acting as a first ultrasonic generator electrode. Each of the second sensor pixels may also include circuitry configured to electrically switch its associated second conductive path to switch between acting as a sensor pixel electrode and acting as a second ultrasonic generator electrode.

[0038] In some specific embodiments of the method, each of the first LAI region and the second LAI region may be electrically coupled to an electrode extension region extending into the adjacent of the first HAI region and the second HAI region, and each electrode extension region may provide a conductive path between the first piezoelectric layer and the first or second LAI region electrically coupled to the first piezoelectric layer.

[0039] In some specific embodiments of the method, the method may further include: receiving reflections of a first ultrasonic wave in a second piezoelectric layer; receiving reflections of a second ultrasonic wave in a third piezoelectric layer; causing a first sensor pixel in a first sensor pixel layer of the device to obtain first fingerprint scan data by measuring the charge generated in the second piezoelectric layer using a first sensor electrode layer; and causing a second sensor pixel in a second sensor pixel layer of the device to obtain second fingerprint scan data by measuring the charge generated in the third piezoelectric layer using a second sensor electrode layer. In such specific embodiments, the first piezoelectric layer may be interposed between the first sensor electrode layer and the second sensor electrode layer, the second piezoelectric layer may be interposed between the first sensor pixel layer and the first sensor electrode layer, and the third piezoelectric layer may be interposed between the second sensor pixel layer and the second sensor electrode layer. The first sensor pixel layer and the first sensor electrode layer may be configured such that: the first sensor pixel measures the charge generated in the second piezoelectric layer in response to the passage of an ultrasonic wave through the second piezoelectric layer, and the second sensor pixel layer and the second sensor electrode layer may be configured such that: the second sensor pixel measures the charge generated in the third piezoelectric layer in response to the passage of an ultrasonic wave through the third piezoelectric layer.

[0040] In some specific embodiments of the method, generating ultrasonic waves from the first piezoelectric layer of the device may include applying a potential across the first piezoelectric layer by a first ultrasonic generator electrode and a second ultrasonic generator electrode. In such embodiments, the first piezoelectric layer may be interposed between the first ultrasonic generator electrode and the second ultrasonic generator electrode.

[0041] In some specific embodiments of the method, a first acoustic masking layer can be inserted between a first sensor electrode layer and a first piezoelectric layer, a second acoustic masking layer can be inserted between a second sensor electrode layer and a first piezoelectric layer, the first acoustic masking layer can form a conductive path between the first sensor electrode layer and the first piezoelectric layer, and the second acoustic masking layer can form a conductive path between the second sensor electrode layer and the first piezoelectric layer.

[0042] In some specific embodiments of the method, the first acoustic masking layer can be inserted between the first sensor electrode layer and the second piezoelectric layer, the second acoustic masking layer can be inserted between the second sensor electrode layer and the third piezoelectric layer, the first acoustic masking layer can form a conductive path between the first sensor electrode layer and the second piezoelectric layer, and the second acoustic masking layer can form a conductive path between the second sensor electrode layer and the third piezoelectric layer.

[0043] In some specific embodiments of the method, the method may further include displaying first graphic content on the first display layer and through the first cover glass; and

[0044] This allows the second graphic content to be displayed on the second display layer and through the second cover glass. In such a specific embodiment, the first display layer may be inserted between the first cover glass and the first sensor pixel layer, the second display layer may be inserted between the second cover glass and the second sensor pixel layer, and both the first and second display layers may be inserted between the first and second cover glass.

[0045] In some specific embodiments of this method, the device may be a mobile communication device.

[0046] In some specific embodiments, an apparatus may be provided comprising: a unit for generating one or more ultrasonic waves; a first component for detecting reflected ultrasonic waves; a first acoustic masking unit; a second component for detecting reflected ultrasonic waves; and a second acoustic masking unit. In such an apparatus, the unit for generating one or more ultrasonic waves, the first component for detecting reflected ultrasonic waves, the second component for detecting reflected ultrasonic waves, the first acoustic masking unit, and the second acoustic masking unit may be arranged in a stacked configuration along a first axis. The first acoustic masking unit may include a first high acoustic impedance (HAI) region and a first low acoustic impedance (LAI) region repeating a first pattern. The second acoustic masking unit may include a second HAI region and a second LAI region repeating a second pattern. The first HAI region may have a higher acoustic impedance than the first LAI region, and the second HAI region may have a higher acoustic impedance than the second LAI region. When viewed along the first axis, the first HAI region may cover the second LAI region, the second HAI region may cover the first LAI region, the first LAI region may cover the second HAI region, and the second LAI region may cover the first HAI region.

[0047] In some specific embodiments of the device, when viewed along the first axis, the first LAI region can be completely covered by the second HAI region, and when viewed along the first axis, the second LAI region can be completely covered by the first HAI region.

[0048] In some specific embodiments of the device, when viewed along the first axis, each first LAI region may occupy a smaller area than the second HAI region that completely covers it, and when viewed along the first axis, each second LAI region may occupy a smaller area than the first HAI region that completely covers it.

[0049] In some specific embodiments of the device, two first reference planes perpendicular to the first axis and spaced apart by a first distance along the first axis can be defined by opposing surfaces of the first LAI region, the first HAI region can be provided by a first gap positioned between the first reference planes, and the first gap may not contain any solid or liquid material.

[0050] In some specific embodiments of the device, the first LAI region may not have a first gap.

[0051] In some specific embodiments of the device, two second reference planes perpendicular to the first axis and spaced apart by a second distance along the first axis may be defined by opposing surfaces of the second LAI region, and the second HAI region may be provided by a second gap positioned between the second reference planes.

[0052] In some specific embodiments of the device, the second LAI region may not have a second gap.

[0053] In some specific embodiments of the device, two second reference planes perpendicular to the first axis and spaced apart by a second distance along the first axis may be defined by opposing surfaces of the second LAI region, the second HAI region may be provided by a second gap positioned between the second reference planes, and the second LAI region may not have a second gap.

[0054] In some specific embodiments of the device, both the first pattern and the second pattern can be a chessboard pattern.

[0055] In some embodiments of the device, each first LAI region may include a continuous material between the first reference planes. In some such embodiments of the device, the continuous material may include copper or aluminum.

[0056] In some embodiments of the device, each first LAI region may include a continuous material between the first reference planes, and each second LAI region may include a continuous material between the second reference planes. In some such embodiments of the device, the continuous material may include copper or aluminum.

[0057] In some specific embodiments of the device, a first LAI region of the first acoustic masking unit may provide a first conductive path between a unit for generating one or more ultrasonic waves and a first component for detecting reflected ultrasonic waves, and a second LAI region of the second acoustic masking unit may provide a second conductive path between a unit for generating one or more ultrasonic waves and a second component for detecting reflected ultrasonic waves. The first component for detecting reflected ultrasonic waves may include a first sensor pixel, each including circuitry configured to electrically switch its associated first conductive path to switch between a sensor pixel electrode acting as a first component for detecting reflected ultrasonic waves and a first ultrasonic generator electrode acting as a unit for generating one or more ultrasonic waves. The second component for detecting reflected ultrasonic waves may include a second sensor pixel, each including circuitry configured to electrically switch its associated second conductive path to switch between a sensor pixel electrode acting as a second component for detecting reflected ultrasonic waves and a second ultrasonic generator electrode acting as a unit for generating one or more ultrasonic waves.

[0058] In some specific embodiments of the device, each of the first LAI region and the second LAI region may be electrically coupled to an electrode extension region extending into the adjacent of the first HAI region and the second HAI region, and each electrode extension region may provide a conductive path between the unit for generating one or more ultrasonic waves and the first or second LAI region electrically coupled to the unit for generating the one or more ultrasonic waves.

[0059] In some specific embodiments of this device, a first component for detecting reflected ultrasonic waves may include a first piezoelectric layer, a first sensor electrode layer, and a first sensor pixel layer, and a second component for detecting reflected ultrasonic waves may include a second piezoelectric layer, a second sensor electrode layer, and a second sensor pixel layer. In such specific embodiments, a unit for generating one or more ultrasonic waves may include a third piezoelectric layer and may be interposed between the first sensor electrode layer and the second sensor electrode layer. The first piezoelectric layer may be interposed between the first sensor pixel layer and the first sensor electrode layer, and the second piezoelectric layer may be interposed between the second sensor pixel layer and the second sensor electrode layer. The first sensor pixel layer and the first sensor electrode layer may be configured such that a first sensor pixel in the first sensor pixel layer measures the charge generated within the first piezoelectric layer in response to ultrasonic waves passing through it, and the second sensor pixel layer and the second sensor electrode layer may be configured such that a second sensor pixel in the second sensor pixel layer measures the charge generated within the second piezoelectric layer in response to ultrasonic waves passing through it.

[0060] In some embodiments of the device, the unit for generating one or more ultrasonic waves may include a first ultrasonic generator electrode, a second ultrasonic generator electrode, and a third piezoelectric layer. In such embodiments, the third piezoelectric layer may be interposed between the first and second ultrasonic generator electrodes, and the first, second, and third piezoelectric electrodes may be configured such that ultrasonic waves are generated by the first piezoelectric layer in response to an applied potential across the first and second ultrasonic generator electrodes.

[0061] In some specific embodiments of the device, the unit for generating one or more ultrasonic waves may include a third piezoelectric layer, a first acoustic masking unit may be inserted between a first sensor electrode layer and the third piezoelectric layer, a second acoustic masking unit may be inserted between a second sensor electrode layer and the third piezoelectric layer, the first acoustic masking unit may form a conductive path between the first sensor electrode layer and the third piezoelectric layer, and the second acoustic masking unit may form a conductive path between the second sensor electrode layer and the third piezoelectric layer.

[0062] In some specific embodiments of the device, the first acoustic masking unit can be inserted between the first sensor electrode layer and the second piezoelectric layer, the second acoustic masking unit can be inserted between the second sensor electrode layer and the third piezoelectric layer, the first acoustic masking unit can form a conductive path between the first sensor electrode layer and the first piezoelectric layer, and the second acoustic masking unit can form a conductive path between the second sensor electrode layer and the second piezoelectric layer.

[0063] In some specific embodiments of the device, the device may further include a first display component, a second display component, a first cover component, and a second cover component. In such specific embodiments, the first display component may be inserted between the first cover component and a first component for detecting reflected ultrasonic waves, the second display component may be inserted between the second cover component and a second component for detecting reflected ultrasonic waves, and both the first display component and the second display component may be inserted between the first cover component and the second cover component.

[0064] In some specific embodiments of the device, the device may be a mobile communication device.

[0065] In some embodiments, an apparatus may be provided comprising: a portion of a first ultrasonic fingerprint sensing system including a first sensor pixel layer, a first piezoelectric layer, and a first electrode layer; a portion of a second ultrasonic fingerprint sensing system including a second sensor pixel layer, a second piezoelectric layer, and a second electrode layer; and a single common controller. In such embodiments, the first sensor pixel layer may include a plurality of first sensor pixels, each configured to, in conjunction with the first electrode layer, measure the amount of charge generated within the first piezoelectric layer in response to ultrasonic wave transmission through it; and the second sensor pixel layer may include a plurality of second sensor pixels, each configured to, in conjunction with the second electrode layer, measure the amount of charge generated within the second piezoelectric layer in response to ultrasonic wave transmission through it. Furthermore, at least the first sensor pixel layer and the second sensor pixel layer can be operatively connected to a single common controller. This portion of the first fingerprint sensing system can be located adjacent to a first side of the device, and this portion of the second fingerprint sensing system can be located adjacent to a second side of the device opposite to the first side of the device. The single common controller can be configured such that the first sensor pixel layer obtains a fingerprint scan from the first side of the device by scanning the first sensor pixel to obtain a measured charge amount, and that the second sensor pixel layer obtains a fingerprint scan from the second side of the device by scanning the second sensor pixel to obtain a measured charge amount.

[0066] In some embodiments of this device, a single common controller may include one or more processors and a switching element configured to switch between at least a first configuration and a second configuration. In such embodiments, in the first configuration, one or more first conductive paths from a first sensor pixel layer may be electrically connected to the one or more processors, and one or more second conductive paths from a second sensor pixel layer may not be electrically connected to the one or more processors; and in the second configuration, the one or more second conductive paths from the second sensor pixel layer may be electrically connected to the one or more processors, and the one or more first conductive paths from the first sensor pixel layer may not be electrically connected to the one or more processors. In such embodiments, the switching element may be configured to switch between the first configuration and the second configuration in response to receiving one or more control signals.

[0067] In some specific embodiments of the device, the one or more processors may be a single processor.

[0068] In some specific embodiments of the device, the one or more processors may be located on a single die.

[0069] In some specific embodiments of the device, the device may further include a first display layer, a second display layer, a first cover glass, and a second cover glass. In such embodiments, the first display layer may be inserted between the first cover glass and the first sensor pixel layer, the second display layer may be inserted between the second cover glass and the second sensor pixel layer, and both the first display layer and the second display layer may be inserted between the first cover glass and the second cover glass.

[0070] In some specific embodiments of the device, the device may be a mobile communication device.

[0071] In some specific embodiments, a method may be provided, comprising: causing a portion of a first ultrasonic fingerprint sensing system, including a first sensor pixel layer, a first piezoelectric layer, and a first electrode layer, to generate a first ultrasonic wave, wherein the first ultrasonic fingerprint sensing system is part of a device; causing a portion of a second ultrasonic fingerprint sensing system, including a second sensor pixel layer, a second piezoelectric layer, and a second electrode layer, to generate a second ultrasonic wave, wherein the second ultrasonic fingerprint sensing system is also part of the device; and causing a single common controller to: cause a first sensor pixel in the first sensor pixel layer to measure the amount of charge generated in the first piezoelectric layer in response to a reflected portion of the first ultrasonic wave passing through the first piezoelectric layer; cause a second sensor pixel in the second sensor pixel layer to measure the amount of charge generated in the second piezoelectric layer in response to a reflected portion of the second ultrasonic wave passing through the second piezoelectric layer; obtaining a fingerprint scan from a first side of the device by scanning the first sensor pixel to obtain the measured amount of charge; and obtaining a fingerprint scan from a second side of the device opposite to the first side of the device by scanning the second sensor pixel to obtain the measured amount of charge. In such specific embodiments, a first ultrasonic fingerprint sensing system and a second ultrasonic fingerprint sensing system may be in the device, and at least both the first sensor pixel layer and the second sensor pixel layer may be operatively connected to a single common controller. The portion of the first fingerprint sensing system may be located adjacent to a first side of the device, and the portion of the second fingerprint sensing system may be located adjacent to a second side of the device opposite to the first side of the device.

[0072] In some specific embodiments of the method, a single common controller may include one or more processors and a switching element configured to switch between at least a first configuration and a second configuration. In such embodiments, in the first configuration, one or more first conductive paths from a first sensor pixel layer may be electrically connected to the one or more processors, and one or more second conductive paths from a second sensor pixel layer may not be electrically connected to the one or more processors; in the second configuration, the one or more second conductive paths from the second sensor pixel layer may be electrically connected to the one or more processors, and the one or more first conductive paths from the first sensor pixel layer may not be electrically connected to the one or more processors; and the switching element may be configured to switch between the first configuration and the second configuration in response to receiving one or more control signals.

[0073] In some specific implementations of this method, the one or more processors may be a single processor.

[0074] In some specific implementations of this method, the one or more processors may be located on a single die.

[0075] In some specific embodiments of this method, the device may be a mobile communication device.

[0076] In some embodiments, an apparatus may be provided. The apparatus may include: a unit for generating one or more ultrasonic waves; a first component for detecting reflected ultrasonic waves; a second component for detecting reflected ultrasonic waves; and a single common controller. In such embodiments, both the first component for detecting reflected ultrasonic waves and the second component for detecting reflected ultrasonic waves are operatively connected to the single common controller. The first component for detecting reflected ultrasonic waves may be positioned adjacent to a first side of the apparatus, and the second component for detecting reflected ultrasonic waves may be positioned adjacent to a second side of the apparatus opposite to the first side. The single common controller may be configured such that the first component for detecting reflected ultrasonic waves obtains a fingerprint scan from the first side of the apparatus and the second component for detecting reflected ultrasonic waves obtains a fingerprint scan from the second side of the apparatus.

[0077] In some embodiments of the device, a single common controller may include one or more processors and a switching element configured to switch between at least a first configuration and a second configuration. In such embodiments, in the first configuration, one or more first conductive paths from a first component for detecting reflected ultrasonic waves may be electrically connected to the one or more processors, and one or more second conductive paths from a second component for detecting reflected ultrasonic waves may not be electrically connected to the one or more processors; in the second configuration, one or more second conductive paths from the second component for detecting reflected ultrasonic waves may be electrically connected to the one or more processors, and the one or more first conductive paths from the first component for detecting reflected ultrasonic waves may not be electrically connected to the one or more processors; and the switching element may be configured to switch between the first and second configurations in response to receiving one or more control signals.

[0078] In some specific embodiments of the device, the one or more processors may be a single processor.

[0079] In some specific embodiments of the device, the one or more processors may be located on a single die.

[0080] In some specific embodiments of the device, the device may further include a first display component, a second display component, a first cover component, and a second cover component. In such specific embodiments, the first display component may be inserted between the first cover component and a first component for detecting reflected ultrasonic waves, the second display component may be inserted between the second cover component and a second component for detecting reflected ultrasonic waves, and both the first display component and the second display component may be inserted between the first cover component and the second cover component.

[0081] In some specific embodiments of the device, the device may be a mobile communication device.

[0082] In some embodiments, an apparatus may be provided including a controller and an ultrasonic fingerprint sensing system, the ultrasonic fingerprint sensing system including a sensor pixel layer, a first piezoelectric layer, and an electrode layer. In such embodiments, the sensor pixel layer may include a plurality of sensor pixels, each sensor pixel being configured to combine with the electrode layer to measure the amount of charge generated within the first piezoelectric layer in response to ultrasonic wave transmission through the first piezoelectric layer, the first piezoelectric layer being positioned within the apparatus such that a first distance between the first piezoelectric layer and a first side of the apparatus is less than a second distance between the first piezoelectric layer and a second side of the apparatus opposite to the first side of the apparatus, and the controller may be configured to obtain a fingerprint scan by: causing the ultrasonic fingerprint sensing system to generate ultrasonic waves during a first time period beginning at a first time; selecting a selected delay period from a first delay period associated with the first side of the apparatus and a second delay period different from the first delay period and associated with the second side of the apparatus; causing the sensor pixels to measure the amount of charge generated within the first piezoelectric layer during a second time period beginning at a second time selected at least based on the first time and the selected delay period; and generating a fingerprint scan based on the amount of charge measured by the sensor pixels during the second time period.

[0083] In some specific embodiments of the device, the device may also include an acoustic conductive spacer inserted between the first piezoelectric layer and a second side of the device.

[0084] In some specific embodiments of the device, the device may also include an acoustically conductive compliant layer that is also inserted between the first piezoelectric layer and the second side of the device.

[0085] In some specific embodiments of this device, the first delay period may be shorter than the second delay period.

[0086] In some specific embodiments of the device, the device may further include a first display layer, a second display layer, a first cover glass, and a second cover glass. In such embodiments, the first display layer may be interposed between the first cover glass and the first sensor pixel layer, the second display layer may be interposed between the second cover glass and the first sensor pixel layer, and both the first and second display layers may be interposed between the first and second cover glass. The first cover glass may be part of a first side of the device, and the second cover glass may be part of a second side of the device.

[0087] In some embodiments of the device, the device may further include a first touch sensing system configured to detect touch input to a first cover glass and a second touch sensing system configured to detect touch input to a second cover glass. In such embodiments, the controller may be further configured to combine fingerprint scanning with obtaining touch input information from the first and second touch sensing systems, and to select a first delay period or a second delay period as a selected delay period, at least in part, based on touch events on a first side or a second side of the device indicated by the touch input information.

[0088] In some specific embodiments, a method may be provided, comprising: causing an ultrasonic fingerprint sensing system of a device to generate ultrasonic waves during a first time period beginning at a first time; selecting a selected delay period from a first delay period associated with a first side of the device and a second delay period different from the first delay period and associated with a second side of the device opposite to the first side of the device; causing sensor pixels of the ultrasonic fingerprint sensing system to measure the amount of charge generated in a first piezoelectric layer during the second time period, the second time period beginning at a second time selected at least based on the first time and the selected delay period; and generating a fingerprint scan based on the amount of charge measured by the sensor pixels of the ultrasonic fingerprint sensing system during the second time period.

[0089] In some specific embodiments of the method, the ultrasonic fingerprint sensing system can be separated from the second side of the device by an acoustic conductive spacer inserted between the ultrasonic fingerprint sensing system and the second side of the device.

[0090] In some specific embodiments of the method, the device may also include an acoustic conduction compliance layer that is also inserted between the ultrasonic fingerprint sensing system and a second side of the device.

[0091] In some specific implementations of this method, the first delay period may be shorter than the second delay period.

[0092] In some specific embodiments of the method, the device further includes a first display layer, a second display layer, a first cover glass, and a second cover glass, wherein the first display layer may be inserted between the first cover glass and the first sensor pixel layer, the second display layer may be inserted between the second cover glass and the first sensor pixel layer, and both the first display layer and the second display layer may be inserted between the first cover glass and the second cover glass. The first cover glass may be part of a first side of the device, and the second cover glass may be part of a second side of the device.

[0093] In some specific embodiments of the method, the device may further include a first touch sensing system configured to detect touch input to a first cover glass and a second touch sensing system configured to detect touch input to a second cover glass. In such embodiments, the method may further include obtaining touch input information from the first touch sensing system configured to detect touch input to the first cover glass and the second touch sensing system configured to detect touch input to the second cover glass, in conjunction with obtaining a fingerprint scan, and selecting a first delay period or a second delay period as a selected delay period, at least in part based on the touch input information indicating a touch event on a first side or a second side of the device.

[0094] In some embodiments, an apparatus may be provided, comprising an ultrasonic fingerprint sensing unit and a controller. In such embodiments, the ultrasonic fingerprint sensing unit may be positioned within the apparatus such that a first distance between the ultrasonic fingerprint sensing unit and a first side of the apparatus is less than a second distance between the ultrasonic fingerprint sensing unit and a second side of the apparatus opposite to the first side of the apparatus, and the controller may be configured to acquire a fingerprint scan by: causing the ultrasonic fingerprint sensing unit to generate ultrasonic waves during a first time period beginning at a first time; selecting a selected delay period from a first delay period associated with the first side of the apparatus and a second delay period different from the first delay period and associated with the second side of the apparatus; and causing the ultrasonic fingerprint sensing unit to acquire a fingerprint scan during a second time period, the second time period beginning at a second time selected at least based on the first time and the selected delay period.

[0095] In some specific embodiments of the device, the device may also include an acoustic conductive spacer inserted between the ultrasonic fingerprint sensing unit and a second side of the device.

[0096] In some specific embodiments of the device, the device may also include an acoustic conduction compliance layer that is also inserted between the ultrasonic fingerprint sensing unit and a second side of the device.

[0097] In some specific embodiments of this device, the first delay period may be shorter than the second delay period.

[0098] In some specific embodiments of the device, the device may further include a first display component, a second display component, a first cover component, and a second cover component. In such embodiments, the first display component may be inserted between the first cover component and the ultrasonic fingerprint sensing unit, the second display component may be inserted between the second cover component and the ultrasonic fingerprint sensing unit, and both the first and second display components may be inserted between the first and second cover components. The first cover component may be part of a first side of the device, and the second cover component may be part of a second side of the device.

[0099] In some embodiments of the device, the device may further include a first touch sensing unit configured to detect touch input to a first covering member and a second touch sensing unit configured to detect touch input to a second covering member. In such embodiments, the controller may be further configured to combine fingerprint scanning with obtaining touch input information from the first and second touch sensing units, and to select a first delay period or a second delay period as a selected delay period, at least in part, based on touch events on a first side or a second side of the device indicated by the touch input information.

[0100] In some specific embodiments, a non-transitory computer-readable medium storing computer-executable instructions may be provided, which, when executed by one or more processors, cause the one or more processors to: cause a first piezoelectric layer of the device to generate ultrasonic waves; cause a first ultrasonic wave in the ultrasonic waves to pass through a first acoustic masking layer of the device and propagate toward a first side of the device; cause a second ultrasonic wave in the ultrasonic waves to pass through a second acoustic masking layer of the device and propagate toward a second side of the device opposite to the first side of the device; cause a first sensor pixel in a first sensor pixel layer of the device to acquire first fingerprint scan data based on reflection of the first ultrasonic wave from the first side of the device; and cause a second sensor pixel in a second sensor pixel layer of the device to acquire second fingerprint scan data based on reflection of the second ultrasonic wave from the second side of the device. In such a device, for example, a first sensor pixel layer, a first acoustic masking layer, a first piezoelectric layer, a second acoustic masking layer, and a second sensor pixel layer may be arranged in a stacked configuration along a first axis. The first acoustic masking layer may include a first high acoustic impedance (HAI) region and a first low acoustic impedance (LAI) region that repeat a first pattern. The second acoustic masking layer may include a second HAI region and a second LAI region that repeat a second pattern. The first HAI region may have a higher acoustic impedance than the first LAI region, and the second HAI region may have a higher acoustic impedance than the second LAI region. When viewed along the first axis, the first HAI region may cover the second LAI region, the second HAI region may cover the first LAI region, the first LAI region may cover the second HAI region, and the second LAI region may cover the first HAI region.

[0101] In some such embodiments, the device may be configured such that: when viewed along a first axis, the first LAI region is completely covered by the second HAI region, and when viewed along the first axis, the second LAI region is completely covered by the first HAI region.

[0102] In some specific embodiments of the non-transitory computer-readable medium, the device may be configured such that, when viewed along a first axis, each first LAI region occupies a smaller area than a second HAI region that completely covers it, and when viewed along the first axis, each second LAI region occupies a smaller area than a first HAI region that completely covers it.

[0103] In some specific embodiments of the non-transitory computer-readable medium, the device may be configured such that two first reference planes perpendicular to the first axis and spaced apart by a first distance along the first axis may be defined by opposing surfaces of a first LAI region, the first HAI region may be provided by a first gap positioned between the first reference planes, and the first gap may not contain any solid or liquid material.

[0104] In some specific embodiments of the non-transitory computer-readable medium, the device can be configured such that the first LAI region does not have a first gap.

[0105] In some specific embodiments of the non-transitory computer-readable medium, the device may be configured such that two second reference planes perpendicular to the first axis and spaced apart by a second distance along the first axis are defined by opposing surfaces of the second LAI region, and the second HAI region is provided by a second gap positioned between the second reference planes.

[0106] In some specific embodiments of the non-transitory computer-readable medium, the device can be configured such that the second LAI region does not have a second gap.

[0107] In some specific embodiments of the non-transitory computer-readable medium, the device may be configured such that: two second reference planes perpendicular to the first axis and spaced apart by a second distance along the first axis are defined by opposing surfaces of the second LAI region, the second HAI region is provided by a second gap positioned between the second reference planes, and the second LAI region does not have the second gap.

[0108] In some specific embodiments of the non-transitory computer-readable medium, the device can be configured such that both the first pattern and the second pattern are chessboard patterns.

[0109] In some specific embodiments of this non-transitory computer-readable medium, the device may be configured such that each first LAI region comprises a continuous material between the first reference planes. In some such specific embodiments of this non-transitory computer-readable medium, the device may be configured such that the continuous material comprises copper or aluminum.

[0110] In some specific embodiments of this non-transitory computer-readable medium, the device may be configured such that each first LAI region comprises a continuous material between first reference planes, and each second LAI region comprises a continuous material between second reference planes. In some such specific embodiments of this non-transitory computer-readable medium, the device may be configured such that the continuous material comprises copper or aluminum.

[0111] In some specific embodiments of the non-transitory computer-readable medium, the device may be configured such that: a first LAI region of a first acoustic masking layer provides a first conductive path between a first sensor pixel layer and a first piezoelectric layer; a second LAI region of a second acoustic masking layer provides a second conductive path between a second sensor pixel layer and a first piezoelectric layer; each of the first sensor pixels includes circuitry configured to electrically switch its associated first conductive path to switch between acting as a sensor pixel electrode and acting as a first ultrasonic generator electrode; and each of the second sensor pixels includes circuitry configured to electrically switch its associated second conductive path to switch between acting as a sensor pixel electrode and acting as a second ultrasonic generator electrode.

[0112] In some specific embodiments of the non-transitory computer-readable medium, the device may be configured such that each of the first LAI region and the second LAI region is electrically coupled to an electrode extension region extending into an adjacent one of the first HAI region and the second HAI region, and each electrode extension region in the electrode extension region provides a conductive path between the first piezoelectric layer and the first or second LAI region electrically coupled to the first piezoelectric layer.

[0113] In some specific embodiments of the non-transitory computer-readable medium, the non-transitory computer-readable medium may also store additional computer-executable instructions that, when executed by the one or more processors, cause the one or more processors to receive a reflection of a first ultrasonic wave in a second piezoelectric layer; receive a reflection of a second ultrasonic wave in a third piezoelectric layer; cause a first sensor pixel in a first sensor pixel layer of the device to obtain first fingerprint scan data by measuring the charge generated in the second piezoelectric layer using a first sensor electrode layer; and cause a second sensor pixel in a second sensor pixel layer of the device to obtain second fingerprint scan data by measuring the charge generated in the third piezoelectric layer using a second sensor electrode layer. In such specific embodiments, the device can be configured such that: a first piezoelectric layer is inserted between a first sensor electrode layer and a second sensor electrode layer; a second piezoelectric layer is inserted between a first sensor pixel layer and a first sensor electrode layer; a third piezoelectric layer is inserted between a second sensor pixel layer and a second sensor electrode layer; the first sensor pixel layer and the first sensor electrode layer are configured such that the first sensor pixel measures the charge generated in the second piezoelectric layer in response to ultrasonic waves passing through it; and the second sensor pixel layer and the second sensor electrode layer are configured such that the second sensor pixel measures the charge generated in the third piezoelectric layer in response to ultrasonic waves passing through it.

[0114] In some specific embodiments of this non-transitory computer-readable medium, the device can be configured such that...

[0115] In some specific embodiments of the non-transitory computer-readable medium, computer-executable instructions causing the first piezoelectric layer of the device to generate ultrasonic waves may include computer-executable instructions causing the one or more processors to apply a potential across the first piezoelectric layer by the first ultrasonic generator electrode and the second ultrasonic generator electrode, wherein in the device, the first piezoelectric layer is interposed between the first ultrasonic generator electrode and the second ultrasonic generator electrode.

[0116] In some specific embodiments of the non-transitory computer-readable medium, the device may be configured such that: a first acoustic masking layer is inserted between a first sensor electrode layer and a first piezoelectric layer, a second acoustic masking layer is inserted between a second sensor electrode layer and a first piezoelectric layer, the first acoustic masking layer forms a conductive path between the first sensor electrode layer and the first piezoelectric layer, and the second acoustic masking layer forms a conductive path between the second sensor electrode layer and the first piezoelectric layer.

[0117] In some specific embodiments of the non-transitory computer-readable medium, the device may be configured such that: a first acoustic masking layer is inserted between a first sensor electrode layer and a second piezoelectric layer, a second acoustic masking layer is inserted between a second sensor electrode layer and a third piezoelectric layer, the first acoustic masking layer forms a conductive path between the first sensor electrode layer and the second piezoelectric layer, and the second acoustic masking layer forms a conductive path between the second sensor electrode layer and the third piezoelectric layer.

[0118] In some embodiments of the non-transitory computer-readable medium, the medium may also store additional computer-executable instructions that, when executed by the one or more processors, cause the one or more processors to: display first graphic content on a first display layer and through a first cover glass, and display second graphic content on a second display layer and through a second cover glass. In such embodiments, the device may be configured such that: the first display layer is interposed between the first cover glass and a first sensor pixel layer, the second display layer is interposed between the second cover glass and a second sensor pixel layer, and both the first and second display layers are interposed between the first and second cover glasses.

[0119] In some specific embodiments of this non-transitory computer-readable medium, the device may be a mobile communication device.

[0120] In some specific embodiments, a non-transitory computer-readable medium storing computer-executable instructions, which, when executed by one or more processors, cause the one or more processors to: cause a portion of a first ultrasonic fingerprint sensing system, comprising a first sensor pixel layer, a first piezoelectric layer, and a first electrode layer, to generate a first ultrasonic wave, wherein the first ultrasonic fingerprint sensing system is part of a device; cause a portion of a second ultrasonic fingerprint sensing system, comprising a second sensor pixel layer, a second piezoelectric layer, and a second electrode layer, to generate a second ultrasonic wave, wherein the second ultrasonic fingerprint sensing system is also part of the device; and cause a single common controller to: cause a first sensor pixel in the first sensor pixel layer to measure the amount of charge generated within the first piezoelectric layer in response to a reflected portion of the first ultrasonic wave transmitting through the first piezoelectric layer; cause a second sensor pixel in the second sensor pixel layer to measure the amount of charge generated within the second piezoelectric layer in response to a reflected portion of the second ultrasonic wave transmitting through the second piezoelectric layer; obtain a fingerprint scan from a first side of the device by scanning the first sensor pixel to obtain the measured amount of charge; and obtain a fingerprint scan from a second side of the device opposite to the first side of the device by scanning the second sensor pixel to obtain the measured amount of charge. Such specific embodiments may be provided for an apparatus including a first ultrasonic fingerprint sensing system and a second ultrasonic fingerprint sensing system, such that at least the first sensor pixel layer and the second sensor pixel layer are operatively connected to a single common controller, the portion of the first fingerprint sensing system being located adjacent to a first side of the apparatus, and the portion of the second fingerprint sensing system being located adjacent to a second side of the apparatus opposite to the first side of the apparatus.

[0121] In some embodiments of this non-transitory computer-readable medium, the device may be configured such that a single common controller includes one or more processors and a switching element configured to switch between at least a first configuration and a second configuration. In such embodiments, in the first configuration, one or more first conductive paths from a first sensor pixel layer may be electrically connected to the one or more processors, and one or more second conductive paths from a second sensor pixel layer may not be electrically connected to the one or more processors; in the second configuration, the one or more second conductive paths from the second sensor pixel layer may be electrically connected to the one or more processors, and the one or more first conductive paths from the first sensor pixel layer may not be electrically connected to the one or more processors; the switching element may be configured to switch between the first configuration and the second configuration in response to receiving one or more control signals; and the non-transitory computer-readable medium may also store additional computer-executable instructions that, when executed by the one or more processors, cause the one or more processors to: cause the one or more control signals to be sent to the switching element.

[0122] In some specific embodiments of a non-transitory computer-readable medium, the device may be configured such that the one or more processors are a single processor.

[0123] In some specific embodiments of a non-transitory computer-readable medium, the device may be configured such that the one or more processors are disposed on a single die.

[0124] In some specific embodiments of this non-transitory computer-readable medium, the device may be a mobile communication device.

[0125] In some specific embodiments, a non-transitory computer-readable medium storing computer-executable instructions, which, when executed by one or more processors, cause the one or more processors to: cause an ultrasonic fingerprint sensing system of the device to generate ultrasonic waves during a first time period beginning at a first time; select a selected delay period from a first delay period associated with a first side of the device and a second delay period different from the first delay period and associated with a second side of the device opposite to the first side of the device; cause sensor pixels of the ultrasonic fingerprint sensing system to measure the amount of charge generated in a first piezoelectric layer during a second time period beginning at a second time selected at least based on the first time and the selected delay period; and generate a fingerprint scan based on the amount of charge measured by the sensor pixels of the ultrasonic fingerprint sensing system during the second time period.

[0126] In some specific embodiments of the non-transitory computer-readable medium, the device can be configured such that the ultrasonic fingerprint sensing system is separated from the second side of the device by an acoustic conductive spacer inserted between the ultrasonic fingerprint sensing system and the second side of the device.

[0127] In some specific embodiments of the non-transitory computer-readable medium, the device may be configured such that it further includes an acoustically conductive compliant layer also interposed between the ultrasonic fingerprint sensing system and a second side of the device.

[0128] In some specific embodiments of this non-transitory computer-readable medium, the first delay period may be less than the second delay period.

[0129] In some embodiments of this non-transitory computer-readable medium, the device may be configured such that it further includes a first display layer; a second display layer; a first cover glass; and a second cover glass. In such embodiments, the first display layer may be interposed between the first cover glass and a sensor pixel, the second display layer may be interposed between the second cover glass and a sensor pixel, both the first and second display layers may be interposed between the first and second cover glasses, the first cover glass may be part of a first side of the device, and the second cover glass may be part of a second side of the device.

[0130] In some embodiments of the non-transitory computer-readable medium, the device may be configured such that it further includes a first touch sensing system configured to detect touch input to a first cover glass and a second touch sensing system configured to detect touch input to a second cover glass. In such embodiments, the non-transitory computer-readable medium may also store additional computer-executable instructions that, when executed by the one or more processors, cause the one or more processors to: obtain touch input information from the first touch sensing system configured to detect touch input to the first cover glass and from the second touch sensing system configured to detect touch input to the second cover glass, in conjunction with obtaining a fingerprint scan, and to select a first delay period or a second delay period as a selected delay period, at least in part based on touch events on a first side or a second side of the device indicated by the touch input information. Attached Figure Description

[0131] Details of one or more specific embodiments of the subject matter described in this specification are set forth in the accompanying drawings and the following description. Other features, aspects, and advantages will become apparent from the specification, drawings, and claims. Note that relative dimensions in the drawings may not be depicted to scale. Similar reference numerals and names in different drawings indicate similar elements.

[0132] Figure 1 Exemplary components of an exemplary ultrasonic fingerprint sensing system according to some of the disclosed specific embodiments are shown.

[0133] Figure 2 A representative description of various aspects of a 4×4 pixel array of sensor pixels used in an ultrasonic fingerprint sensing system is presented.

[0134] Figure 3 An example of a device for a dual ultrasonic fingerprint sensor system with a shared common controller is depicted.

[0135] Figure 4A portion of another exemplary device is depicted for a dual ultrasonic fingerprint sensor system with a shared common controller.

[0136] Figure 5 An example of a device having a bidirectional ultrasonic fingerprint sensor system that uses a distance gate method to obtain a fingerprint scan is depicted.

[0137] Figure 6 A portion of another exemplary apparatus is depicted having a dual ultrasonic fingerprint sensor system that uses a distance gate method to obtain fingerprint scans.

[0138] Figure 7 A cross-sectional schematic diagram depicts a portion of an exemplary device including an ultrasonic fingerprint sensor.

[0139] Figure 8 A cross-sectional schematic diagram depicts a portion of another exemplary device including an ultrasonic fingerprint sensor.

[0140] Figure 9 A cross-sectional schematic diagram depicts a portion of another exemplary device including an ultrasonic fingerprint sensor.

[0141] Figure 10 A portion of an exemplary device is depicted, wherein a piezoelectric ultrasonic generator layer is used for both ultrasonic wave generation and ultrasonic wave detection.

[0142] Figure 11 Describing the structural similarity with Figure 10 An exploded isometric view of an example of a device that is somewhat similar to another device.

[0143] Figure 12 A view depicting two checkerboard acoustic masking patterns.

[0144] Figure 13 A view depicting two parallel strip acoustic masking patterns is shown.

[0145] Figure 14 A cross-sectional schematic diagram depicts a portion of another exemplary device including an ultrasonic fingerprint sensor.

[0146] Figure 15 A flowchart is depicted for a technique using a bidirectional ultrasonic fingerprint sensor.

[0147] Figure 16 This is a block diagram illustrating exemplary components of an apparatus according to some of the disclosed specific embodiments.

[0148] The accompanying drawings are provided to facilitate understanding of the concepts discussed in this disclosure, and the drawings are intended to illustrate some specific embodiments that fall within the scope of this disclosure, but are not intended to be limiting—specific embodiments consistent with this disclosure and not depicted in the drawings are still considered to be within the scope of this disclosure. Detailed Implementation

[0149] For the purpose of describing the innovative aspects of this disclosure, the following description relates to certain specific embodiments. However, those skilled in the art will readily recognize that the teachings herein can be applied in many different ways. The specific embodiments described can be implemented in any device, apparatus, or system, including biometric systems as disclosed herein. Furthermore, it is contemplated that the specific embodiments described can be included in or associated with a variety of electronic devices, such as, but not limited to: mobile phones, cellular phones with multimedia internet capabilities, mobile TV receivers, wireless devices, smartphones, smart cards, etc. Devices, personal data assistants (PDAs), wireless email receivers, handheld or portable computers, netbooks, notebooks, smartbooks, tablets, GPS receivers / navigators, cameras, digital media players (such as MP3 players), portable video cameras, game consoles, clocks, calculators, television monitors, flat panel displays, e-reading devices (e.g., e-readers), mobile health devices, computer monitors, electronic photographs, stereo systems, DVD players, CD players, VCRs, radios, portable memory chips, parking timers, aesthetic structures (such as displaying images of a piece of jewelry or clothing), and various EMS devices. The teachings herein can also be applied to components such as, but not limited to, consumer electronics, liquid crystal devices, and electrophoresis equipment. Therefore, these teachings are not intended to be limited to the specific embodiments depicted in the accompanying drawings, but rather have broad applicability, as will be apparent to those skilled in the art.

[0150] Fingerprints are now widely used for authentication, for example, to allow a specific user access to a specific device or to authenticate transactions performed using the device. As used herein, the term “finger” can refer to any finger of the hand, including the thumb. Therefore, for the purposes of this disclosure, a thumbprint should be understood to also constitute a “fingerprint.” Similarly, for the purposes of this disclosure, the index “finger” should be understood to include “finger and thumb.” Thus, for example, the index “all ten fingers of a person” should be understood to refer to all ten fingers of that person’s two hands.

[0151] One specific type of fingerprint sensor that can be used for fingerprint authentication purposes is the ultrasonic fingerprint sensor. Existing ultrasonic fingerprint sensors comprise a stack of multiple layers that can be placed, for example, under the display of a device and used to read fingerprints through the device's display. Such ultrasonic fingerprint sensors may include a piezoelectric emitter layer, a piezoelectric sensor material layer, and a sensor pixel layer. In some such ultrasonic fingerprint sensors, the piezoelectric emitter layer and the piezoelectric sensor material layer may be the same piezoelectric material layer; for example, the same piezoelectric material can be used to generate ultrasonic waves in response to an applied potential across the material and to convert the reflected ultrasonic waves received by the piezoelectric material into a potential that can be measured by the sensor pixel layer. Ultrasonic fingerprint sensors are particularly well-suited for integration into mobile electronic devices because they can acquire fingerprint scans through a variety of different materials—including, for example, the device housing and / or the device display panel. Specifically, ultrasonic fingerprint sensors can be positioned under the display of a mobile device, both concealing the ultrasonic fingerprint sensor from view and allowing the display to utilize the area that would otherwise be occupied if the fingerprint sensor were not placed under the display.

[0152] However, existing ultrasonic fingerprint sensors are designed to be inherently unidirectional; for example, they acquire fingerprints from only a single surface of the device. This is generally not a problem because portable devices typically incorporating ultrasonic fingerprint sensors are usually intended for active interaction by the user in a limited set of orientations, in which the device's display faces the user. For example, such devices are typically interacted by the user in one of four different orientations: vertical, reverse vertical, horizontal, and reverse horizontal—however, in each of these orientations, the device's display faces the user. In such devices, it is therefore generally known (by both the device's controller and the user) which surface of the device can be used to acquire a fingerprint scan. For example, if the ultrasonic fingerprint sensor is positioned below the device's display, the device's controller can, for example, instruct the user (via graphical prompts) to place their fingertip on the display or in a specific location on the display to perform a fingerprint scan. Alternatively, if the device instead has an ultrasonic fingerprint sensor configured to acquire a fingerprint scan on the device side opposite the display via the device housing, the device's controller can then instruct the user to place their fingertip on the back of the device to perform a fingerprint scan. In addition, users of such devices will know which side of the device has fingerprint scanning functionality and therefore will know which surface of the device to place their finger on to perform a fingerprint scan.

[0153] However, recent advancements in consumer electronics have seen the introduction of mobile devices (e.g., smartphones, where displays are located on two opposite sides). In some instances, such devices can even feature wraparound or partially wraparound displays, allowing three, four, or more sides of the device to display graphics in response to commands from a graphics processing unit. Such devices can offer users the opportunity to use the device in a greater number of different orientations, such as portrait, reverse portrait, landscape, and reverse landscape, where the first side of the device has a display facing the user, and similar orientations where the device is flipped so that a second side opposite the first side faces the user. Due to this flexibility in potential device orientations, there may be uncertainty regarding, for example, which surface of the device the device's controller and / or the user will receive a fingerprint scan from.

[0154] This document discloses various bidirectional ultrasonic fingerprint sensor systems that can be used to provide fingerprint scanning capability to surfaces on a device located on opposite sides of the fingerprint sensor system. Such bidirectional ultrasonic fingerprint sensor systems can allow fingerprint scans to be obtained from surfaces on either side of the ultrasonic fingerprint sensor. In some embodiments, such fingerprint scans can be obtained simultaneously, although in other embodiments, they can be obtained nearly simultaneously or on either of two opposing surfaces of the device. Because such bidirectional ultrasonic fingerprint sensor systems are capable of obtaining fingerprint scans from either side or both sides of the device, such devices can be configured to adapt to any orientation in which a user is using them. For example, if the device is displaying a software application that requires fingerprint authentication to a specific area of ​​a graphical user interface shown on the side of the device that the user is actively using, the device can enable the bidirectional ultrasonic fingerprint sensor in such a device to obtain a fingerprint scan from that area of ​​the display used to display the graphical user interface.

[0155] This article discusses several different specific implementations of a bidirectional ultrasonic fingerprint sensor. In one such implementation, the bidirectional ultrasonic fingerprint sensor system may include two sets of piezoelectric emitter layers, piezoelectric sensor material layers, and sensor pixel layers, wherein each set of piezoelectric emitter, piezoelectric sensor material, and sensor pixel layers is arranged to acquire fingerprint scanning information from opposite sides of the device. In this implementation, the two sets of piezoelectric emitter, piezoelectric sensor material, and sensor pixel layers may be connected to a common application-specific integrated circuit, a processor, or other electronic components configured to control the operation of the ultrasonic fingerprint sensor.

[0156] In another specific embodiment discussed herein, the device may include an ultrasonic fingerprint sensor having a piezoelectric emitter, a piezoelectric sensor material, and a sensor pixel layer. Such a layer may be placed adjacent to one side of the device (e.g., adjacent to the display layer of the device), but may also have a low acoustic impedance path extending between the piezoelectric emitter, piezoelectric sensor material, and sensor pixel layer and the opposite side of the device. A distance-gate technique can be used to obtain fingerprint scans from either side of such a device, allowing the detection of reflected ultrasonic waves from one side of the device or the other, but excluding the detection of reflected ultrasonic waves from the other side of the device.

[0157] In other specific embodiments discussed herein, the device may have a piezoelectric material layer for generating ultrasonic waves or pulses, and two sensor pixel arrays positioned such that the piezoelectric material layer is interposed therebetween. Such devices may also include two acoustic masking layers, each interposed between the piezoelectric material and a different one of the sensor pixel arrays. Each acoustic masking layer may be characterized by a pattern of high acoustic impedance (HAI) regions and low acoustic impedance (LAI) regions, arranged such that the HAI regions in each acoustic masking layer are generally aligned with the LAI regions in the other acoustic masking layer.

[0158] Before discussing the specific implementation methods described above, refer to Figure 1 and Figure 2 It describes the various components that can exist in an ultrasonic fingerprint sensing system.

[0159] Figure 1 Exemplary components of an exemplary ultrasonic fingerprint sensing system according to some of the disclosed embodiments are shown. As with other disclosed embodiments, the types, numbers, and arrangements of the elements, as well as the dimensions of the elements, are merely examples. According to this embodiment, the ultrasonic fingerprint sensing system 102 includes a piezoelectric layer 124, an electrode layer 126 on one side of the piezoelectric layer 124, and a sensor pixel array 122 in a sensor pixel layer 120 adjacent to a second opposite side of the piezoelectric layer 124. In this embodiment, the piezoelectric layer 124 is an ultrasonic transceiver layer comprising one or more piezoelectric polymers; that is, the piezoelectric layer 124 can be used to alternatively generate or detect ultrasonic waves.

[0160] According to this example, electrode layer 126 resides between passivation layer 172 and piezoelectric layer 124. In some examples, passivation layer 172 may include an adhesive, such as an epoxy resin film, a polymer layer (such as a polyethylene terephthalate (PET) layer), etc.

[0161] In this example, the sensor pixel layer 120 (which may also be referred to as a thin-film transistor (TFT) layer) includes a TFT substrate and circuitry for the sensor pixel array 122. The sensor pixel layer 120 may include one or more types of metal-oxide-semiconductor field-effect transistors (MOSFETs) fabricated by depositing an active semiconductor thin film layer, a dielectric layer, and metal contacts on the TFT substrate. In some examples, the TFT substrate may be a non-conductive material, such as glass.

[0162] In this example, device 100 includes a display layer 106, which in this instance includes an organic light-emitting diode (OLED) display. Here, the OLED display layer 106 is attached to the sensor pixel layer 120 via an adhesive layer 170.

[0163] According to this specific embodiment, the sensor pixel layer 120, the sensor pixel array 122, and the electrode layer 126 are electrically coupled to at least a portion of the control system 156, for example, via a flexible printed circuit (FPC), which can be electrically bonded to one or more conductive contacts 158 and one or the other side of the piezoelectric layer 124.

[0164] In this example, the control system 156 is an application-specific integrated circuit (ASIC) configured to control the ultrasonic fingerprint sensing system 102 such that one or more ultrasonic waves 152 are generated within the piezoelectric layer 124 and propagate toward the cover glass 104. The cover glass 104 may also optionally incorporate a touch sensing system, such as a mutual capacitance or self-capacitance touch sensing system, which can be used to provide input to the underlying display layer 1406 (in other embodiments, the touch sensing system may be configured as part of the display layer 1406).

[0165] According to this example, ultrasonic waves 152 are emitted through the sensor pixel layer 120, the display layer 106, and the cover glass 104. According to this example, the reflection 154 of the ultrasonic waves 152 is caused by the acoustic impedance contrast at (or near) the interface 115 between the outer surface of the cover glass 104 and anything in contact with that outer surface (which could be air or the surface of a target object, such as the ridges and valleys of a fingerprint). (As used herein, the term "finger" can refer to any finger, including the thumb. Therefore, a thumbprint would be considered a type of "fingerprint.") Figure 1 As shown, press your fingertip to make it contact the outer surface of the covering glass 104.

[0166] According to some examples, the local intensity of the reflection 154 of the ultrasonic wave 152 detected by sensor pixel 122 can be used to generate a mapping of the reflected acoustic wave intensity across the sensing area of ​​fingerprint sensing system 102. Such a mapping can then be used to generate a fingerprint scan dataset, where locations exhibiting higher reflected ultrasonic wave intensity correspond to locations where the cover glass 104 is in contact with air, and locations exhibiting lower reflected ultrasonic wave intensity correspond to locations where the cover glass 104 is in contact with a solid object (e.g., a person's skin / fingerprint ridges). In some such embodiments, the ultrasonic signal used by control system 156 for fingerprint-based authentication can be based on reflections 154 from the cover glass 104 / finger interface 115 detected by sensor pixel array 122.

[0167] Figure 2 A 4×4 pixel array of sensor pixels 222 for an ultrasonic fingerprint sensing system is representatively depicted. Each sensor pixel 222 may be associated, for example, with a local region of piezoelectric sensor material (PSM) (e.g., provided by a piezoelectric layer as discussed above), a peak detection diode (D1), and a readout transistor; many or all of these elements may be formed on or in a substrate to form sensor pixel circuitry 236. In practice, the local region of the piezoelectric sensor material of each sensor pixel 222 may convert the received ultrasonic energy into electrical charge. The peak detection diode D1 may record the maximum amount of charge detected in the local region of the piezoelectric sensor material PSM. Each row of the sensor pixel array 235 may then be scanned, for example, via a row selection mechanism, a gate driver, or a shift register, and the readout transistor of each column may be triggered to allow the amplitude of the peak charge of each sensor pixel 222 to be read by additional circuitry (e.g., a multiplexer and an A / D converter). Each sensor pixel circuitry 236 may include one or more TFTs to allow gating, addressing, and resetting of the associated sensor pixel 222.

[0168] Each sensor pixel circuit 236 can provide a small portion of information about the object detected by the ultrasonic sensor system. Although for illustrative purposes... Figure 2 The example shown has a relatively coarse resolution, but ultrasonic sensors with resolutions on the order of 500 pixels per inch or higher can be configured with appropriately scaled structures. The detection area of ​​an ultrasonic sensor system can be selected based on the intended object to be detected or the area where fingerprint detection is potentially to be performed. For example, the detection area can range from approximately 5mm x 5mm for a single finger to approximately 3 inches x 3 inches for four fingers. Smaller and larger areas (including square, rectangular, and non-rectangular geometries) can be appropriately used for target objects.

[0169] While the above discussion provides information on general operational concepts related to ultrasonic fingerprint sensors, the following discussion explores various specific implementations of the ultrasonic fingerprint sensors disclosed herein. The apparatus characterized in the following discussion may be, for example, part of a mobile communication device (e.g., a smartphone, tablet computer, etc.) or other device, or may be a mobile communication device or other device.

[0170] Detailed Implementation of Shared Controller

[0171] Figure 3 An example of a portion of a device for a dual ultrasonic fingerprint sensor system with a shared common controller is depicted. Figure 3 The present invention depicts an apparatus 300 comprising a first cover glass 304, a first display layer 306, a second cover glass 308, and a second display layer 310. It should be understood that the cover glasses 304 and 308 may be made of glass, sapphire, plastic, or other light-transmitting materials to allow the display layers 306 and 310 to be seen through the cover glass, and that the cover glasses 304 and 308 are not limited to being made of glass, although the term is used throughout this disclosure for these and similar elements.

[0172] The device 300 may further include a housing 364 that can accommodate a first cover glass 304, a first display layer 306, a second cover glass 308, and a second display layer 310, such that the first display layer 306 and the second display layer 310 face opposite directions. The first cover glass 304 may form part of a first side 366 of the device 300, and the second cover glass 308 may form part of a second side 368 of the device 300 opposite to the first side 366. In some embodiments, a first touch sensing system 303 may be disposed between the first display layer 306 and the first cover glass 304, and a second touch sensing system 307 may be disposed between the second display layer 310 and the second cover glass 308. The first touch sensing system 303 and the second touch sensing system 307 may be, for example, capacitive touch sensors or other touch input sensing systems capable of detecting touch events of a user's fingertips.

[0173] The device 300 may also include two fingerprint sensing system portions, namely, a first fingerprint sensing system portion 302a and a second fingerprint sensing system portion 302b. The first fingerprint sensing system portion 302a may, for example, include a first sensor pixel layer 320 comprising a plurality of first sensor pixels 322, which can be configured to measure the charge level (hereinafter referred to simply as "charge") within a first piezoelectric layer 324 in conjunction with a first sensor electrode layer 326. Similarly, the second fingerprint sensing system portion 302b may include a second sensor pixel layer 330 comprising a plurality of second sensor pixels 332, which can be configured to measure the charge level within a second piezoelectric layer 334 in conjunction with a second sensor electrode layer 336. In the depicted specific embodiment, the fingerprint sensing system portion is configured to have piezoelectric layers 324 and 334 that function as ultrasonic transceivers, i.e., allowing the sensor pixel layers to switch between two modes: one mode where the circuitry in sensor pixel layers 320 and 330, in conjunction with sensor electrode layers 326 and 336, generates a potential across piezoelectric layers 324 and 334 to generate ultrasonic pulses; and another mode where the circuitry in sensor pixel layers 320 and 330 obtains a measurement of the amount of local charge generated within these piezoelectric layers in response to ultrasonic waves passing through them. It should be understood that in some embodiments, fingerprint sensing system portions 302a and 302b may be independently operable, while in other embodiments, their operability may be linked.

[0174] like Figure 3 As shown, both the first fingerprint sensing system portion 302a and the second fingerprint sensing system portion 302b are operatively connected to a common controller 356. The controller 356 may, for example, be equipped with inputs and outputs sufficient to allow the controller to interact with both the first fingerprint sensing system portion 302a and the second fingerprint sensing system portion 302b simultaneously. In some embodiments, the first fingerprint sensing system portion 302a and the second fingerprint sensing system portion 302b may actually be treated by the controller as a single large fingerprint scanner, thus the output is split between the two fingerprint sensing systems. The controller may be configured, as needed, to allow scanning of one or more portions of the “composite” fingerprint sensing system at any given time, for example, only the portion corresponding to the first fingerprint sensing system portion 302a, only the portion corresponding to the second fingerprint sensing system portion 302b, or both portions thereof.

[0175] This type of implementation allows for the implementation of two ultrasonic fingerprint sensing systems in a device using only a single common controller (e.g., a controller provided by a single die or chip). This can reduce costs, as the controller used for an ultrasonic fingerprint system can be the most complex and expensive component in the production of an ultrasonic fingerprint sensing system. Therefore, avoiding the need for two ultrasonic fingerprint sensing system controllers can significantly reduce costs. Such an ultrasonic fingerprint sensing system controller can be configured, for example, as an application-specific integrated circuit (ASIC) mounted to a flexible substrate. For example, in a flexible chip implementation, it can include conductive traces to electrically connect the two ultrasonic fingerprint sensing systems to a common shared controller.

[0176] Such specific implementations can allow a device (such as device 300) to obtain fingerprint scans individually or simultaneously from a surface on either side of the device.

[0177] Figure 4 A portion of another exemplary device is depicted for a dual ultrasonic fingerprint sensor system with a shared common controller. Figure 4 Device 400 and Figure 3 The device 300 is somewhat similar to, and is with Figure 3 The components are similar Figure 4 The components are indicated by graphic symbols that share the same last two digits. Unless otherwise discussed below, regarding Figure 3 The above discussion of the components can be assumed to be similarly applicable to the components. Figure 4 Similar components.

[0178] The main difference between device 400 and device 300 is that, in device 400, the first fingerprint sensing system portion 402a and the second fingerprint sensing system portion 402b are at least partially connected to a common controller 456 via a switching element 458, which can be at least controllable so that one or the other of the first fingerprint sensing system portion 402a and the second fingerprint sensing system portion 402b is operatively connected to the common controller 456 at any given time. Thus, for example, the switching element 458 (which is shown as a single switch, but in most embodiments, as a set of multiple switches, each associated with a different trace or signal path used by the fingerprint sensing system portion) can be used to switch between different sets of signal lines that can be used to control the sensor pixel layers 420 and 430, respectively. In such embodiments, the common controller 456 can be considered as part of a larger common controller 456' that includes the switching element 458. For example, the common controller 456 can be provided by one or more processors that, together with the switching element 458, provide the larger common controller 456'.

[0179] In such embodiments, the common controller 456 may not be able to simultaneously acquire fingerprint scans from both sides of the device 400 because only one of the two fingerprint sensing system sections 402a and 402b is operatively connected to the common controller at any given time. However, the common controller 456 can, for example, cause the switching element 458 to switch relatively quickly (e.g., on the order of less than 100 milliseconds, e.g., 30 ms to 60 ms or 40 ms to 50 ms) between the first fingerprint sensing system section 402a and the second fingerprint sensing system section 402b, thereby allowing ultrasonic fingerprint scans to be acquired sequentially from the two ultrasonic fingerprint sensing systems in a rapid manner (e.g., almost simultaneously). In some such embodiments, the controller may be configured to first attempt to acquire a fingerprint scan from one ultrasonic fingerprint sensing system, and if the first attempt fails, for example, no valid fingerprint scan is acquired or fewer than the expected number of valid fingerprints are acquired, then it must subsequently attempt to acquire a fingerprint scan from the other ultrasonic fingerprint sensing system. Such embodiments may be practiced, for example, with any of the embodiments discussed herein.

[0180] Detailed Implementation of Distance Gating

[0181] Figure 5 An example of a device having a bidirectional ultrasonic fingerprint sensor system that uses a distance gate method to obtain a fingerprint scan is depicted. Figure 5 A device 500 is depicted, comprising a first cover glass 504 covering a first display layer 506 and a second cover glass 508 covering a second display layer 510. The first cover glass 504 may form part of a first side 566 of the device 500, and the second cover glass 508 may form part of a second side 568 of the device 500 opposite to the first side 566. In some embodiments, a first touch sensing system 503 may be disposed between the first display layer 506 and the first cover glass 504, and a second touch sensing system 507 may be disposed between the second display layer 510 and the second cover glass 508. The first touch sensing system 503 and the second touch sensing system 507 may be, for example, capacitive touch sensors or other touch input sensing systems capable of detecting touch events of a user's fingertips.

[0182] The device 500 may further include a fingerprint sensing system 502, which may include, for example, a sensor pixel layer 520 comprising a plurality of sensor pixels 522, a sensor electrode layer 526, and a piezoelectric layer 524 interposed between the sensor pixel layer and the sensor electrode layer. The sensor pixels 522 may include circuitry configured to switch between two modes, for example, a mode in which a potential can be applied across the piezoelectric layer 524 by the sensor electrode layer 522 and the sensor pixels 526 to cause the piezoelectric layer 524 to generate ultrasonic pulses, and a mode in which the sensor pixels 522 and the sensor electrode layer 526 can obtain a measurement of the charge level generated in the piezoelectric layer 524 in response to ultrasonic waves passing through it, thereby allowing the acquisition of a scanned image of a fingerprint. When the piezoelectric layer 524 generates ultrasonic pulses, the ultrasonic waves from the piezoelectric layer 524 can propagate outwards in opposite directions toward the first cover glass 504 and the second cover glass 508. Ultrasonic waves reaching the first cover glass 504 or the second cover glass 508 can be reflected back toward the piezoelectric layer 524 at different intensities depending on the material pressed against the cover glass 504 and 508. The intensity of the locally reflected ultrasonic waves, which can then be detected by the sensor pixel layer 520, can be used to generate an image or reconstruction of the object pressed against the first cover glass 504 or the second cover glass 508.

[0183] The device 500 may further include a spacer 560 and a compliant layer 562. The spacer 560 and compliant layer 562 may, for example, be interposed between the fingerprint sensing system 502 and the second display layer 510. As shown, the compliant layer 562 may be positioned between the spacer 560 and the second display layer 510, or alternatively, between the spacer 560 and the fingerprint sensing system 502. The spacer 560 may provide an acoustic conduction path facilitating the propagation of ultrasonic waves toward the second cover glass 508, and the compliant layer 562, which may be a gel or other deformable coupling layer (e.g., an elastomer), may provide a compliant interface extending the acoustic conduction path, allowing ultrasonic waves traveling toward the second cover glass 508 to reach the second cover glass 508 without excessive attenuation or reflection. The compliant layer 562 may be used to prevent the formation of gaps in the acoustic conduction path between the fingerprint sensing system 502 and the second cover glass 508 that could interfere with sound wave propagation, such as gaps caused by tolerance accumulation within the device, for example, due to thermal expansion or other sources. For example, the spacer may be a battery or other component that can provide part of the sound transmission path through the device from the fingerprint sensing system 502 and the second display layer 510.

[0184] Due to the different distances between the piezoelectric layer 524 and the first cover glass 504 and the second cover glass 508, ultrasonic waves emitted from the piezoelectric layer 524 can have different propagation times to the first cover glass 504 and the second cover glass 508. For example, compared to the distance between the piezoelectric layer 524 and the first cover glass 504, the increased distance between the piezoelectric layer 524 and the second cover glass 508 caused by the spacer 560 can result in a shorter propagation time for ultrasonic waves from the piezoelectric layer 524 to the first cover glass 504 (and the return propagation time of the portion reflected back) than the propagation time for ultrasonic waves from the piezoelectric layer 524 to the second cover glass 508 (and the return propagation time of the portion reflected back).

[0185] Since the ultrasonic waves generated by the piezoelectric layer 524 can be reflected back towards the piezoelectric layer 524 by the first cover glass 504 and the second cover glass 508 at different timings, the controller that can be used to control the fingerprint sensing system can, for example, use techniques such as distance gate delay to selectively obtain the measurement results of the charge generated in the piezoelectric layer 524 due to the ultrasonic waves reflected from the first cover glass 504 or the second cover glass 508 (or an object pressed to contact it, such as a fingertip).

[0186] For example, the controller can be configured to cause the piezoelectric layer 524 to generate ultrasonic waves during a first time period beginning at a first time, and subsequently cause the sensor pixel 522 to measure the amount of peak charge generated within the piezoelectric layer 524 as the reflected ultrasonic waves pass through it during a second time period beginning at a second time, in order to scan a fingerprint from one side of the device 500 having the first cover glass 504. The second time can be selected as an amount based on a first delay period following the first time period, the first delay period being selected such that the ultrasonic waves reflected from the first cover glass 504 can reach the piezoelectric layer 524 after the start of the second time period. The second time period can then be selected to be long enough that the ultrasonic waves reflected from the first cover glass 504 have passed through the piezoelectric layer 524 before reaching the end of the second time period. The second time period can also be selected to be short enough that the ultrasonic waves emitted by the piezoelectric layer 524 and reflected from the second cover glass 508 have not yet reached the piezoelectric layer 524 before the end of the second time period. Therefore, the peak charge read by sensor pixel 522 during the second time period can represent the highest acoustic impedance encountered by the ultrasonic wave when it reaches the outer surface of the first cover glass 504 (and thus represent the fingerprint or more precisely its reverse side).

[0187] Alternatively, the controller may cause sensor pixel 522 to measure the amount of peak charge generated within piezoelectric layer 524 due to the reflected ultrasonic waves passing through it during a third time period, beginning after the first time period, in order to scan a fingerprint from one side of the device 500 having the second cover glass 508. The third time period may be selected as an amount based on a second delay period following the first time period, the second delay period being selected such that the ultrasonic waves reflected from the second cover glass 508 can reach the piezoelectric layer 524 after the start of the second time period. The third time period may then be selected to be long enough that the ultrasonic waves reflected from the second cover glass 508 have passed through the piezoelectric layer 524 before reaching the end of the third time period. Therefore, the peak charge read by sensor pixel 522 during the third time period can represent the highest acoustic impedance encountered by the ultrasonic waves as they reach the outer surface of the second cover glass 508 (and thus represent the fingerprint, or more precisely, its reverse side).

[0188] The controller may also optionally cause the sensor pixels to undergo a reset operation before acquiring such measurements, for example, to clear any peak charge measurements that may reside within the sensor circuitry before the desired measurement is obtained. Once the controller has acquired the peak charge measurements from the sensor pixels of the ultrasonic fingerprint sensing system, it can generate a fingerprint scan based on the amount of charge measured, as previously discussed. In some embodiments, the controller may cause sensor pixel 522 to measure the peak amount of charge generated within the piezoelectric layer as reflected ultrasonic waves pass through it during both a second and a third time period, wherein a reset operation is performed between these two time periods—such a technique allows for the rapid and orderly acquisition of ultrasonic fingerprint scans from both sides of the device, which appear to the user to be acquired simultaneously. In such embodiments, the controller may cause fingerprint scans to be acquired in association with only one ultrasonic wave generation event, for example, using the same ultrasonic wave or pulse to generate the reflected ultrasonic wave, and subsequently detected by the same sensor circuitry during two distinct, non-overlapping time intervals, with the reflected ultrasonic wave detected during each time interval representing fingerprint scans acquired from opposite sides of the device.

[0189] Figure 6 A portion of another exemplary apparatus is depicted having a dual ultrasonic fingerprint sensor system that uses a distance gate method to obtain fingerprint scans. Figure 6 Device 600 and Figure 5 The device 500 is somewhat similar, and is... Figure 5 The components are similar Figure 6 The components are indicated by graphic symbols that share the same last two digits. Unless otherwise discussed below, regarding Figure 5The above discussion of the components can be assumed to be similarly applicable to the components. Figure 6 Similar components.

[0190] Figure 6 The device 600 is identical to the device 500, except that instead of using a single piezoelectric layer 524 to both generate and receive reflected ultrasonic waves, the device 600 has a piezoelectric ultrasonic generator layer 614 for generating ultrasonic waves and a separate first piezoelectric layer 624 for receiving reflected ultrasonic waves. The device 600 also has a first ultrasonic generator electrode 616 and a second ultrasonic generator electrode 618, which can be used to apply a potential across the piezoelectric ultrasonic generator layer 614 to generate ultrasonic waves. The first ultrasonic generator electrode 616 can also be used in conjunction with a sensor pixel 622 to obtain a measurement of the charge generated within the first piezoelectric layer 624 for fingerprint scanning.

[0191] Specific implementation methods of acoustic masking layer

[0192] Figure 7 A cross-sectional schematic diagram depicts a portion of an exemplary device including an ultrasonic fingerprint sensor. Device 700 (a portion of which is shown) includes dual-display functionality. For example, device 700 includes a first display layer 706 and a first cover glass 704 on one side, and a second display layer 710 and a second cover glass 708 on a second opposite side. The first display layer 706 and the second display layer 710 may be, for example, OLED, LCD, POLED, or other types of pixelated display systems that can be controlled by a graphics processing unit or other controller and used to display pixel-based graphics. The first display layer 706 and the second display layer 710 may also include, for example, components or layers that can be used to provide operational functionality for such display layers, such as a backlight layer, a passivation layer, a thin-film transistor layer, etc.

[0193] Interposed between the first display layer 706 and the second display layer 710 is an ultrasonic fingerprint sensing system 702. In this example, the ultrasonic fingerprint sensing system 702 includes a piezoelectric ultrasonic generator layer 714 interposed between a first ultrasonic generator electrode 716 and a second ultrasonic generator electrode 718. The first ultrasonic generator electrode 716 and the second ultrasonic generator electrode 718 can be configured by a controller of the device 700 to have an applied potential across them, thereby causing the piezoelectric ultrasonic generator layer 714 to vibrate and generate ultrasonic waves propagating in a direction perpendicular to the piezoelectric ultrasonic generator layer 714.

[0194] The first acoustic masking layer 728 and the second acoustic masking layer 738 may each have a repeating pattern of HAI region 740 and LAI region 742 (the HAI region 740 and LAI region 742 of the first acoustic masking layer 728 may also be referred to herein as the first HAI region and the first LAI region, and the HAI region 740 and LAI region 742 of the second acoustic masking layer 738 may also be referred to herein as the second HAI region and the second LAI region).

[0195] HAI region 740 has a higher acoustic impedance than LAI region 742. For example, ultrasound waves that propagate from the first ultrasound generator electrode 716 or the second ultrasound generator electrode 718 and enter a region of LAI region 742 experience a relatively large number of reflections (and therefore less transmission across HAI region 740) compared to ultrasound waves that propagate from the first ultrasound generator electrode 716 or the second ultrasound generator electrode 718 and enter a region of LAI region 742. Therefore, the first acoustic masking layer 728 and the second acoustic masking layer 738 can generally act as spatial filters, allowing ultrasound waves that pass through the first acoustic masking layer 728 or the second acoustic masking layer 738 to experience less signal strength loss in the portion of LAI region 742 corresponding to the portion corresponding to HAI region 740 when passing through the first acoustic masking layer 728 or the second acoustic masking layer 738.

[0196] The HAI regions 740 and LAI regions 742 of the repeating patterns of the first acoustic masking layer 728 and the second acoustic masking layer 738 can be arranged, for example, such that when viewed along an axis 712 perpendicular to the first acoustic masking layer 728 and / or the second acoustic masking layer 738, the HAI regions 740 and LAI regions 742 of the first acoustic masking layer respectively cover the LAI regions 742 and HAI regions 740 of the second acoustic masking layer 738, and vice versa. In some embodiments, the HAI regions 740 and LAI regions 742 of the repeating patterns of the first acoustic masking layer 728 and the second acoustic masking layer 738 can be arranged, for example, such that the LAI regions 742 of the first acoustic masking layer 728 and the second acoustic masking layer 738 are completely covered by the HAI regions 740 of the second acoustic masking layer 738 and the first acoustic masking layer 728, respectively. In some other such embodiments, the dimensions of the LAI region 742 of the first acoustic masking layer 728 and the second acoustic masking layer 738 can be designed such that, when viewed along an axis perpendicular to the first acoustic masking layer 728 and the second acoustic masking layer 738, each occupies a smaller area than the HAI region 740 that it completely covers.

[0197] It should be understood that, in the context of this disclosure, unless otherwise specified, the phrase “A and B overlap when viewed along [a specific direction]…” means the state in which item A covers item B when viewed along the indicated direction (e.g., item A at least partially obscures item B, assuming item A is opaque) and the state in which item B covers item A when viewed along the indicated direction (e.g., item B at least partially obscures item A, assuming item B is opaque).

[0198] The arrangement of LAI region 742 and HAI region 740 (as discussed above and as...) Figure 7 The arrangement depicted allows for the modulation of the intensity of ultrasonic waves passing through the first acoustic masking layer 728 and the second acoustic masking layer 738 based on the XY position. In practice, such modulation can be used to subdivide larger ultrasonic waves into multiple smaller ultrasonic waves, each associated with a specific XY position (the XY plane is perpendicular to axis 712). These positions can be selected such that ultrasonic waves exiting either side are modulated such that, for each XY position, a higher intensity ultrasonic wave is emitted from either the first acoustic masking layer 728 or the second acoustic masking layer 738 in one direction through the stack of layers than in the other.

[0199] exist Figure 7 In this context, this is visually depicted by wavy lines representing the ultrasonic waves 750 generated by the piezoelectric ultrasonic generator layer 714, which have approximately the same intensity across the piezoelectric ultrasonic generator layer 714. However, after the ultrasonic waves 750 pass through the first acoustic masking layer 728 or the second acoustic masking layer 738, the resulting ultrasonic waves will have a different intensity. Figure 7 The wavy lines in the diagram represent the emitted ultrasonic pulse portions 752 and 754, which pass through the LAI region 742 and have a higher signal strength compared to the portion of the ultrasonic wave that passes through the HAI region 740 (which is not shown, although such portions of the ultrasonic wave may still exist after passing through the first acoustic masking layer 728 or the second acoustic masking layer 738, albeit with a significantly reduced intensity).

[0200] The HAI region 740 and LAI region 742 of the first acoustic masking layer 728 and the second acoustic masking layer 738 can be provided, for example, with materials having different specific acoustic impedances. For example, the LAI region 742 in the first acoustic masking layer 728 can be provided by a structure that provides a continuous acoustic wave conduction path between two first reference planes 746, which can be defined, for example, to coincide with the surfaces of these LAI regions 742. However, the HAI region 740 of the first acoustic masking layer 728 can provide a discontinuous acoustic wave conduction path; for example, a gap can exist for at least a portion of the distance between the first reference planes 746 within the HAI region 740. Such a gap can be provided by the absence of any solid or liquid material within the gap, and can be, for example, an air gap (or a gap filled with some other gas). The difference in acoustic impedance present during the transition from a medium (such as the medium of the first ultrasonic generator electrode 716) to a medium (such as the gas in the HAI region 740) causes the HAI region 740 to reflect a larger portion of the ultrasonic waves compared to the LAI region 742 (or otherwise prevent them from passing through), which can be seen as a much lower (or virtually non-existent) acoustic impedance difference between the first ultrasonic generator electrode 716 and the LAI region 742.

[0201] The LAI region 742 in the first acoustic masking layer 728 can provide a continuous acoustic wave conduction path and therefore may not have such gaps. In some embodiments, the LAI region 742 may be provided by a solid homogeneous material such as copper, aluminum, etc., which may be selected to be similar to the material used in the first ultrasonic generator electrode 716, thereby reducing the amount of ultrasonic energy that may be reflected at the interface between the first ultrasonic generator electrode 716 and the LAI region 742. In some instances, the first ultrasonic generator electrode 716 and the LAI region 742 may be configured as a single continuous structure having both elements therein.

[0202] Of course, it should be understood that the above discussion regarding the composition of the HAI region 740 and LAI region 742 of the first acoustic masking layer 728 also applies to the HAI region 740 and LAI region 742 of the second acoustic masking layer 738. For example, the LAI region 742 in the second acoustic masking layer 738 can be provided by a structure that provides a continuous acoustic wave conduction path between two second reference planes 748, which can be defined, for example, to coincide with the surfaces of these LAI regions 742. However, the HAI region 740 of the second acoustic masking layer 738 can provide a discontinuous acoustic conduction path; for example, gaps can exist for at least a portion of the distance between the second reference planes 748 within the HAI region 740, such as gaps similar to those discussed above.

[0203] Figure 7 The first acoustic masking layer 728 is shown adjacent to the first sensor electrode layer 726, which in turn may be adjacent to the first piezoelectric layer 724 interposed between the first sensor electrode layer 726 and the first sensor pixel layer 720 containing a plurality of first sensor pixels 722. It should be understood that in Figure 7 In the accompanying drawings and other figures herein, layers shown as adjacent to each other may, in some embodiments, include one or more other layers interposed between each other, such as one or more electrically insulating layers, adhesive layers, or other thin layers that may provide structural and / or electrical features. Each of the first sensor pixels 722 may each include, for example, circuitry (e.g., including one or more thin-film transistors) such that the circuitry measures, for example, the amount of charge generated within the first piezoelectric layer 724 in response to local vibrations of the first piezoelectric layer 724 caused by ultrasonic waves passing through the first piezoelectric layer during a given time interval, by measuring the local potential within the first piezoelectric layer 724 between the first sensor pixel 722 and the first sensor electrode layer 726. For example, the first sensor pixel 722 can be made to measure the amount of charge generated in the first piezoelectric layer 724 during a time interval chosen to be sufficiently close in time to be after the emitted ultrasonic pulse 752 has passed through the first piezoelectric layer, such that any charge generated by the portion subsequently reflected back by the emitted ultrasonic pulse 752 toward the piezoelectric ultrasonic generator layer 714 can be measured, thus providing a pixel-by-pixel mapping of the intensity of the reflected ultrasonic waves that can be used to determine the fingerprint scan. Alternatively, the time interval can be chosen to be sufficiently large to measure localized charges generated within the first piezoelectric layer 724 caused by both the emitted ultrasonic pulse 752 and any reflected ultrasonic waves that may be caused by it. In such a specific embodiment, the emitted ultrasonic pulse 752 can provide a generalized amount of uniform charge generated across the first piezoelectric layer 724, which can then be subtracted from the final charge measurement for each pixel, for example, to obtain the amount of charge generated due to the reflected ultrasonic waves.

[0204] The second acoustic masking layer 738 may similarly be adjacent to the second sensor electrode layer 736, which in turn is adjacent to the second piezoelectric layer 734 interposed between the second sensor electrode layer 736 and the second sensor pixel layer 730 containing a plurality of second sensor pixels 732. The second sensor pixels 732 may be controlled together with the second sensor electrode layer 736 to measure the amount of charge generated within the second piezoelectric layer 734 in response to ultrasonic waves or reflected ultrasonic waves passing through it. The second sensor electrode layer 736, the second piezoelectric layer 734, and the second sensor pixel layer 730 may operate, for example, in a manner similar to that of the first sensor electrode layer 726, the first piezoelectric layer 724, and the second sensor pixel layer 730.

[0205] The first acoustic masking layer 728 and the second acoustic masking layer 738 can typically be used to cause the ultrasonic fingerprint sensing system 702 to preferentially scan fingerprints in one direction within the LAI region 742 on one side of the piezoelectric ultrasonic generator layer 714 and preferentially scan fingerprints in another direction within the LAI region 742 on the other side of the piezoelectric ultrasonic generator layer 714. While this can generate grid or checkerboard patterned “holes” in the fingerprint scanning area on each side of the piezoelectric ultrasonic generator layer 714, any potential scan quality problems that might be caused by such holes can be remedied, for example, by employing finer resolutions in the first sensor pixel layer 720 and the second sensor pixel layer 730, respectively.

[0206] In some instances, and due to the presence of HAI regions, such implementations may produce artifacts that can be noticeable in scanned fingerprint images generated using such arrangements. However, since such artifacts are generated by a fixed pattern (e.g., first or second acoustic masking layers 728 and 738), such images can be post-processed, for example by a controller or other processor, using existing background estimation (BGE) and / or raster detection algorithms that allow the removal of such artifacts.

[0207] It should be understood that the piezoelectric ultrasonic generator layer discussed herein can also be simply referred to as a piezoelectric layer, followed by an ordinal indicator, for example, similar to the way the first and second piezoelectric layers discussed above are indexed. In such instances, if the piezoelectric layer providing the functionality of an ultrasonic generator is instead indexed as, for example, the first piezoelectric layer, then other piezoelectric layers (if present) that can be referred to as the aforementioned first and second piezoelectric layers can instead be referred to as, for example, the second and third piezoelectric layers, respectively.

[0208] In various specific embodiments, the gap "A" may typically be occupied by one or more components of the device (e.g., such as a battery) that provide an acoustic transmission path allowing the ultrasonic waves generated by the piezoelectric ultrasonic generator layer 714 (and the ultrasonic waves subsequently reflected by the first cover glass 704 and the second cover glass 708) to transmit. For example, the gap "A" may be composed of a component similar to... Figure 5 The spacer 560 in the middle includes components such as battery filler (and optionally, may also be composed of a conforming layer such as...). Figure 5 (The compliant layer 562 is filled). This guide also applies to the gap "A" visible in the other figures discussed below.

[0209] Figure 8 A cross-sectional schematic diagram depicts a portion of another exemplary device including an ultrasonic fingerprint sensor. Figure 8 Device 800 and Figure 7 The device 7 is somewhat similar to, and is with Figure 7The components are similar Figure 8 The components are indicated by graphic symbols that share the same last two digits. Unless otherwise discussed below, regarding Figure 7 The above discussion of the components can be assumed to be similarly applicable to the components. Figure 8 Similar components.

[0210] Figure 8 Device 800 and Figure 7 The difference in device 700 is that the first ultrasonic generator electrode 816 and the second ultrasonic generator electrode 818 are omitted. Instead, the first ultrasonic generator electrode 816 and the second ultrasonic generator electrode 818 can be replaced by a first acoustic masking layer 828 and a second acoustic masking layer 838. For example, the LAI region 842 adjacent to the first sensor electrode layer 826 can be in conductive contact with the first sensor electrode layer 826, and the LAI region 842 adjacent to the second sensor electrode layer 836 can be in conductive contact with the second sensor electrode layer 836, such that the potential applied across the first sensor electrode layer 826 and the second sensor electrode layer 836 can be generated across the piezoelectric ultrasonic generator layer 814 through a conductive path provided by the LAI region 842 (which can be made of, for example, a conductive material such as a copper- or aluminum-containing material). The device 800 may also include, for example, one or more circuits or other elements that allow the first sensor electrode layer 826 and the second sensor electrode layer 836 to switch between two modes: one mode is for generating a potential across the piezoelectric ultrasonic generator layer 814; the other mode is for use in conjunction with the first sensor pixel layer 820 and the second sensor pixel layer 830 to detect the amount of charge generated in the first piezoelectric layer 824 and the second piezoelectric layer 834, respectively.

[0211] Figure 9 A schematic cross-sectional view depicts a portion of another exemplary device including an ultrasonic fingerprint sensor. Figure 8 The device is the same as 800. Figure 9 Device 900 and Figure 7 The device 7 is somewhat similar to, and is with Figure 7 The components are similar Figure 9 The components are indicated by graphic symbols that share the same last two digits. Unless otherwise discussed below, regarding Figure 7 The above discussion of the components can be assumed to be similarly applicable to the components. Figure 9 Similar components.

[0212] Figure 9 Device 900 and Figure 7The difference in device 700 is that the first sensor electrode layer 926 and the second sensor electrode layer 936 are omitted. Instead, a first ultrasonic generator electrode 916 and a second ultrasonic generator electrode 918 are used to replace the first sensor electrode layers and the second sensor electrode layer, respectively, with a first acoustic masking layer 928 and a second acoustic masking layer 938 providing conductive paths between the first ultrasonic generator electrode 916 and the first piezoelectric layer 924 and between the second ultrasonic generator electrode 918 and the second piezoelectric layer 934. It should be understood that in such a specific embodiment, the first ultrasonic generator electrode 916 and the second ultrasonic generator electrode 918 may alternatively or additionally be regarded as the first sensor electrode layer 926 and the second sensor electrode layer 936.

[0213] For example, the LAI region 942 adjacent to the first ultrasonic generator electrode 916 can be in conductive contact with the first ultrasonic generator electrode 916, and the LAI region 942 adjacent to the second ultrasonic generator electrode 918 can be in conductive contact with the second ultrasonic generator electrode 918, so that a potential can be applied across the piezoelectric ultrasonic generator layer 914 by the first ultrasonic generator electrode 916 and the second ultrasonic generator electrode 918, so that the piezoelectric ultrasonic generator layer 914 generates ultrasonic waves. The first ultrasonic generator electrode 916 and the second ultrasonic generator electrode 918 can also be connected to one or more circuits that allow the first ultrasonic generator electrode 916 and the second ultrasonic generator electrode 918 to be conductively connected to their respective adjacent LAI regions 942, and also act as electrodes that can be used in conjunction with the first sensor pixel layer 920 and the second sensor pixel layer 930, respectively, to measure the amount of charge generated in the first piezoelectric layer 924 and the second piezoelectric layer 934, respectively.

[0214] Figures 7 to 9 The device is characterized by discrete piezoelectric ultrasonic generator and receiver layers. For example, the ultrasonic waves used by the fingerprint sensing system in these figures are generated in the piezoelectric ultrasonic generator layer, while the subsequent detection of the ultrasonic waves (such as reflected ultrasonic waves) is performed using separate first and second piezoelectric layers. However, Figure 10 A portion of an exemplary device 1000 is depicted, wherein a piezoelectric ultrasonic generator layer 1014 is used for both ultrasonic wave generation and ultrasonic wave detection.

[0215] and Figure 8 The device is the same as 800. Figure 10 Device 1000 and Figure 7 The device 7 is somewhat similar to, and is with Figure 7 The components are similar Figure 10 The components are indicated by graphic symbols that share the same last two digits. Unless otherwise discussed below, regarding Figure 7 The above discussion of the components can be assumed to be similarly applicable to the components. Figure 10 Similar components.

[0216] As mentioned above, Figure 10 Device 1000 and Figures 7 to 9 The difference in the device is that the piezoelectric ultrasonic generator layer 1014 is used for both ultrasonic wave generation and ultrasonic wave detection. Therefore, the device 1000 does not include a first piezoelectric layer or a second piezoelectric layer. Instead, the first sensor pixel layer 1020 and the second sensor pixel layer 1030 are configured to measure the charge generated within the piezoelectric ultrasonic generator layer 1014 as ultrasonic waves pass through it.

[0217] In some specific implementations, such as in Figure 8 and Figure 9 In the device, the LAI region 1042 can be used both as an acoustic conduction path that allows a portion of the ultrasonic waves generated by the piezoelectric ultrasonic generator layer 1014 to pass through it with less attenuation than the HAI region 1040, and as a conductive path that allows charge to be delivered to and received from the piezoelectric ultrasonic generator layer 1014. For example, the LAI region 1042 can also be used as an electrode.

[0218] In device 1000, the LAI region 1042 includes an electrode extension region 1044 that extends the material of the LAI region 1042 adjacent to the piezoelectric ultrasonic generator layer 1014 into a position that overlaps with the HAI region 1040 (e.g., when viewed along axis 1012). The LAI region 1042 and the electrode extension region 1044 may be made, for example, of a sound-transmitting and conductive material (e.g., a copper- or aluminum-containing material). The electrode extension region 1044 may be configured to distribute charge more uniformly across the surface of the piezoelectric ultrasonic generator layer 1014, for example, during the application of a potential across the piezoelectric ultrasonic generator layer 1014 to generate ultrasonic waves or during the measurement of the charge generated by ultrasonic waves passing through the piezoelectric ultrasonic generator layer 1014. It should be noted that although the electrode extension region 1044 extends into the gap between the LAI regions 1042 (thus causing the electrode extension region 1044 to overlap with the HAI region 1040 when viewed along axis 1012), it is thinner than the LAI region 1042. For example, the electrode extension region 1044 may be thinner than the distance between the first reference plane 1046 and / or the second reference plane 1048. In such embodiments, the HAI region 1040 may be provided by a gap existing between the surfaces of the electrode extension region 1044 of the first sensor pixel layer 1020 and the first acoustic masking layer 1028, or by a gap existing between the surfaces of the electrode extension region 1044 of the second sensor pixel layer 1030 and the second acoustic masking layer 1038.

[0219] In a specific embodiment such as device 1000, the first sensor pixel layer 1020 and the second sensor pixel layer 1030 may have a first sensor pixel 1022 and a second sensor pixel 1032 respectively including circuitry that allows switching of conductive paths from or to the corresponding LAI region 1042 between different portions of the circuitry (e.g., between a portion of the circuitry that can be used to apply a potential across the piezoelectric ultrasonic generator layer 1014 and other portions of the circuitry that can be used to measure the amount of local charge generated within the piezoelectric ultrasonic generator layer 1014 as ultrasonic waves pass through it).

[0220] Figure 11 An exploded isometric view depicting an example of a device somewhat similar in construction to device 1000 is shown. Device 1100 may, for example, include a first cover glass 1104 that protects a first display layer 1106, which may include a plurality of luminescent and / or color-changeable display pixels (in this example, a 5×5 grid of such display pixels is shown). Device 1100 may similarly include a second cover glass 1108 that covers and protects a second display layer 1110, which may also include a plurality of luminescent and / or color-changeable display pixels (similar to the first display layer 1106, a 5×5 grid of such display pixels is shown in this example).

[0221] Interposed between the first display layer 1106 and the second display layer 1110 is a fingerprint sensing system 1102 and a spacer 1160. The spacer 1160 may be one or more components of the device, such as a battery, and may optionally include a compliance layer. The fingerprint sensing system 1102 may include, for example, a piezoelectric ultrasonic generator layer 1114 interposed between two electrode extension regions 1144. One of the electrode extension regions 1144 is interposed between the piezoelectric ultrasonic generator layer 1114 and a first acoustic masking layer 1128, and the other is interposed between the piezoelectric ultrasonic generator layer 1114 and a second acoustic masking layer 1138. The first acoustic masking layer 1128 and the second acoustic masking layer 1138 may, for example, include a HAI region 1140 and a LAI region 1142. It should be understood that although the electrode extension regions 1144 are shown as elements separated from the LAI region 1142, in some embodiments, they may each be a continuous portion of the corresponding LAI region 1142. It can be seen that each electrode extension region 1144 is separated from each adjacent electrode extension region 1144 by a small gap, thereby allowing each electrode extension region 1144 to be electrically isolated from other electrode extension regions 1144 within the first acoustic masking layer 1128 or the second acoustic masking layer 1138. This allows the electrode extension regions 1144 and their corresponding LAI regions 1142 in the first acoustic masking layer 1128 and the second acoustic masking layer 1138 to serve as individually addressable sensor pixel electrodes for the first sensor pixel 1122 and the second sensor pixel 1132 in the first sensor pixel layer 1120 and the second sensor pixel layer 1130, respectively. Meanwhile, if the circuitry within the first sensor pixel layer 1120 and the second sensor pixel layer 1130 is switched, for example, to a mode in which the electrode extension region 1144 on either side of the piezoelectric ultrasonic generator layer 1114 (and the associated LAI region 1142 of the first acoustic masking layer 1128 and the second acoustic masking layer 1138) can be addressed simultaneously (e.g., the electrode extension region 1144 on one side of the piezoelectric ultrasonic generator layer 1114 can be addressed as a first group and the electrode extension region 1144 on the other side of the piezoelectric ultrasonic generator layer 1114 can be addressed as a second group), this allows the electrode extension region 1144 to be used to apply a potential across the piezoelectric ultrasonic generator layer 1114 for the purpose of generating ultrasonic waves.

[0222] like Figure 11 As can be seen, the LAI regions 1142 in the first acoustic masking layer 1128 and the second acoustic masking layer are arranged in a checkerboard pattern. However, it should be understood that other types of repeating patterns can also be used to achieve a similar effect. For example, the LAI regions 1142 in the first acoustic masking layer 1128 and the second acoustic masking layer 1138 are arranged in a checkerboard pattern, such as... Figure 12 As shown. Figure 12 A view depicting a first acoustic masking layer 1228 (top left) with LAI region 1242a and HAI region 1240a, and a second acoustic masking layer 1238 (top right) with LAI region 1242b and HAI region 1240b. The LAI regions 1242a / b and HAI regions 1240a / b are arranged in an offset checkerboard pattern such that the two checkerboard patterns are complementary when the first acoustic masking layer 1228 and the second acoustic masking layer 1238 overlap, as shown... Figure 12 The image is shown at the bottom center.

[0223] However, Figure 13 The HAI and LAI areas with alternative patterns are depicted. Figure 13 The image depicts a first acoustic masking layer 1328 (top left) with LAI region 1342a and HAI region 1340a, and a second acoustic masking layer 1338 (top right) with LAI region 1342b and HAI region 1340b. The LAI regions 1342a / b and HAI regions 1340a / b are arranged in an offset linear array pattern such that when the first acoustic masking layer 1328 and the second acoustic masking layer 1338 overlap, the two sets of long, thin LAI regions 1342a / b and thin HAI regions 1340a / b complement each other, as shown in the image. Figure 13 The image is shown at the bottom center.

[0224] It should be understood that, although in Figure 11 and Figure 12 The shapes shown are essentially square, but the LAI and HAI regions used in the acoustic masking layers discussed in this paper can also be as shown. Figure 13 The diagram shows a non-square form. For example, the LAI and HAI regions can be rectangular, triangular, circular, etc. In some specific embodiments, the LAI and HAI regions can be shaped such that: the ultrasonic waves passing through the two acoustic masking layers in opposite directions from the piezoelectric layer inserted between the two acoustic masking layers are spatially subdivided in opposite directions, such that when viewed along the wave propagation direction, the high-intensity portions traveling outward from one side of the piezoelectric layer (those passing through the LAI region) overlap with the low-intensity portions traveling outward in the opposite direction (those passing through the HAI region), and vice versa.

[0225] While the sensor pixels depicted in the accompanying figures discussed above are shown to extend along with the LAI regions, it should be understood that in some embodiments, sensor pixels used to measure the charge generated within one or more piezoelectric layers of the apparatus discussed above may each cover one or more LAI regions and / or HAI regions. In some embodiments (e.g., embodiments where the LAI regions are not used as sensor pixel electrodes), multiple sensor pixels may overlap with the same LAI region or different portions of the same plurality of LAI regions. However, in other embodiments (e.g., embodiments where the LAI regions act as sensor pixel electrodes), each LAI region may be covered by only one sensor pixel (although each sensor pixel may still cover one or more LAI regions).

[0226] In some embodiments, the LAI and HAI regions of the first and second acoustic masking layers can be selected and positioned to provide two regularly spaced LAI regions when viewed along an axis perpendicular to the nominal plane of the acoustic masking layers, one such distribution associated with the first acoustic masking layer and the other with the second acoustic masking layer. The LAI regions in the first acoustic masking layer may have the same or similar size and shape, and the LAI regions in the second acoustic masking layer may also have the same or similar size and shape. In some such embodiments, the LAI regions in the first acoustic masking layer may also have the same shape and size as the LAI regions in the second acoustic masking layer, and in some such embodiments, the HAI regions in the first acoustic masking layer may also have the same shape and size as the HAI regions in the second acoustic masking layer. The LAI regions in each distribution can be positioned such that, when viewed along an axis perpendicular to the nominal plane of the acoustic masking layers, the LAI regions of one distribution are positioned in the gaps between the LAI regions of the other distribution, and vice versa. It should be understood that the gaps in each distribution can correspond to the locations of the HAI regions of the corresponding first and second acoustic masking layers. In such an arrangement, the portion of the ultrasonic waves emitted by the piezoelectric ultrasonic generator layer that passes through the LAI region of the acoustic masking layer (in which the piezoelectric ultrasonic generator layer is interposed) can generate higher-intensity ultrasonic waves with a uniform distribution pattern, while the portion of the ultrasonic waves passing through the HAI region generates lower-intensity ultrasonic waves with a similar uniform distribution pattern across the sensing area of ​​the fingerprint sensing system. In some specific embodiments, the acoustic impedance of the HAI region can be high enough that the resulting lower-intensity ultrasonic waves can have negligible or zero intensity. Generally, the distribution of higher-intensity ultrasonic waves emitted by the fingerprint sensing system in each direction can have corresponding lower-intensity (e.g., zero-intensity) ultrasonic waves emitted in another direction from the same location. Such a distribution of higher or lower-intensity ultrasonic waves can effectively stagger the scanning capabilities of the fingerprint sensing system, where each XY position (relative to the scanning plane of the fingerprint sensing system) is oriented biased toward either side of the fingerprint sensing system, thereby avoiding situations where it may be unclear which side of the device the detected higher-intensity ultrasonic waves originate from.

[0227] In some embodiments, the sizes of the LAI regions used in the first and second acoustic masking layers can be chosen to allow more acoustic energy to be emitted in one direction than in the other. For example, if it is desired to detect the presence of a finger on only one of the two opposite sides of the device (as opposed to being able to detect a fingerprint of the same finger), the acoustic masking layer associated with that side of the device can use a smaller LAI region compared to the acoustic masking layer associated with the opposite side of the device. In another alternative embodiment, it may be desirable to obtain fingerprints from either or both of the opposite sides of the device, but it may be desirable to send more ultrasonic energy toward one side of the device (e.g., the side further away from the ultrasonic generator than the other opposite side and potentially experiencing more transmission loss than to the other opposite side). Therefore, the acoustic layer associated with the side of the device closer to the ultrasonic generator can use a smaller LAI region compared to the LAI region in the acoustic masking layer associated with the side of the device further away from the ultrasonic generator.

[0228] In Figure 10 and Figure 11 In another embodiment somewhat similar to these, a device similar to devices 1000 and 1100 can be provided, but the electrode extension regions 1044 and 1144 are omitted. For example, Figure 14 A portion of an exemplary device 1400 is depicted, in which a piezoelectric ultrasonic generator layer 1414 is used for both ultrasonic wave generation and ultrasonic wave detection, but the LAI region 1442 also serves as an electrode without any electrode extension regions (such as electrode extension region 1044). Figures 8 to 11 The device is the same as 800 to 1100. Figure 14 Device 1400 and Figure 7 The device 7 is somewhat similar to, and is with Figure 7 The components are similar Figure 14 The components are indicated by graphic symbols that share the same last two digits. Unless otherwise discussed below, regarding Figure 7 The above discussion of the components can be assumed to be similarly applicable to the components. Figure 14 Similar components.

[0229] Device 1400 can operate in a manner substantially similar to that of devices 1000 and 1100, although due to gaps in charge application, which may appear in the gaps between LAI regions 1442 on each side of the piezoelectric ultrasonic generator layer 1414, the ultrasonic waves generated using the piezoelectric ultrasonic generator layer 1414 may be somewhat non-uniform.

[0230] The various bidirectional ultrasonic fingerprint sensing systems discussed in this article can be implemented, for example, in a device configured to selectively read fingerprints from one side or the other. Figure 15 Examples of techniques that can be used by the controller of such devices to do so are depicted.

[0231] Figure 15 The technology begins at block 1502, where the controller of the device (such as the device discussed above) can receive a signal to initiate fingerprint scanning. In block 1504, in response to receiving the signal, the controller can cause one or more ultrasonic layers of the device's ultrasonic fingerprint system to generate one or more ultrasonic waves.

[0232] In block 1506, the controller can receive data from the device's touch sensing system (e.g., a capacitive touchscreen, etc.) that may indicate one or more touch events that may be occurring on a first side or an opposite second side of the device. Both the first and second sides of the device may be sides from which the device's ultrasonic fingerprint sensing system can be configured to obtain fingerprint scans.

[0233] In block 1508, the controller can cause the ultrasonic fingerprint sensing system to obtain a fingerprint scan from either the first side or the second side, or in some instances from both, based on data from the touch sensing system. For example, if the data from the touch sensing system indicates a touch event on the first side of the device but not the second side, the controller can cause the ultrasonic fingerprint sensing system to obtain a fingerprint scan only from the first side of the device. Conversely, if the data from the touch sensing system indicates a touch event on the second side of the device but not the first side, the controller can cause the ultrasonic fingerprint sensing system to obtain a fingerprint scan only from the second side of the device. In some specific embodiments, if the data from the touch sensing system indicates a touch event on both the first side and the second side of the device, the controller can cause the ultrasonic fingerprint sensing system to obtain a fingerprint scan from both the first side and the second side of the device.

[0234] In the above-described embodiment of the ultrasonic fingerprint sensing system that uses a distance gate delay, selecting from which side of the device to obtain a fingerprint scan may involve, for example, selecting a delay period from two different delay periods (as previously discussed). The selected delay period may be a delay period associated with the side of the device from which the fingerprint scan is obtained.

[0235] Figure 16 This is a block diagram illustrating exemplary components of an apparatus according to some of the disclosed specific embodiments. In this example, apparatus 1600 includes an ultrasonic fingerprint sensing system 1602, a control system 1606, a memory system 1608, and a display system 1610. In some specific embodiments, apparatus 1600 may include an interface system 1604.

[0236] The ultrasonic fingerprint sensing system 1602 may be, for example, one of the ultrasonic fingerprint sensing systems described herein, and may include one or more piezoelectric layers, such as a polyvinylidene fluoride (PVDF) polymer layer or a polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) copolymer layer.

[0237] The data received from the ultrasonic fingerprint sensing system 1602 may sometimes be referred to herein as “fingerprint sensor data,” “fingerprint image data,” “ultrasonic fingerprint data,” “ultrasonic signal,” etc., although this data is typically received from the fingerprint sensing system in the form of an electrical signal and subsequently processed by one or more processors. Therefore, without additional processing, such image data may not be perceptible to humans as an image.

[0238] Control system 1606 may include one or more general-purpose single-chip or multi-chip processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs) or other programmable logic devices, discrete gate or transistor logic components, discrete hardware components, or combinations thereof. In this example, control system 1606 is configured to communicate with and control the ultrasonic fingerprint sensing system 1602 and the display system 1610. According to some examples, control system 1606 may include dedicated components for controlling the ultrasonic fingerprint sensing system 1602. In this example, control system 1606 is also configured to communicate with memory system 1608. According to some examples, control system 1606 may also include one or more memory devices, such as one or more random access memory (RAM) devices, read-only memory (ROM) devices, etc. In some specific embodiments, the functionality of control system 1606 may be partitioned among one or more controllers or processors, such as between a dedicated sensor controller and an application processor of a mobile device.

[0239] In this example, memory system 1608 includes one or more memory devices, such as one or more RAM devices, ROM devices, etc. In some examples, memory system 1608 may include one or more computer-readable media, storage media, and / or storage media. Computer-readable media includes both computer storage media and communication media, including any medium that can be implemented to transfer a computer program from one location to another. Storage media can be any available medium that can be accessed by a computer. In some examples, memory system 1608 may include one or more non-transitory media. By way of example and not limitation, non-transitory media may include RAM, ROM, electrically erasable programmable read-only memory (EEPROM), compact disc ROM (CD-ROM) or other optical disk storage devices, magnetic disk storage devices or other magnetic storage devices, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer.

[0240] Some specific embodiments of device 1600 may include interface system 1604. In some examples, interface system 1604 may include a wireless interface system. In some specific embodiments, interface system 1604 may include a user interface system, one or more network interfaces, one or more interfaces between control system 1606 and ultrasonic fingerprint sensing system 1602, one or more interfaces between control system 1606 and memory system 1608, one or more interfaces between control system 1606 and display system 1610, and / or one or more interfaces between control system 1606 and one or more external device interfaces (e.g., ports or application processors).

[0241] Interface system 1604 may be configured to provide communication between components of device 1600 (which may include wired or wireless communication, electrical communication, radio communication, etc.). In some such examples, interface system 1604 may be configured to provide communication between control system 1606 and ultrasonic fingerprint sensing system 1602. According to some such examples, interface system 1604 may couple at least a portion of control system 1606 to ultrasonic fingerprint sensing system 1602, for example, via a conductive material (e.g., via conductive metal cables or traces). According to some examples, interface system 1604 may be configured to provide communication between device 1600 and other devices and / or humans. In some such examples, interface system 1604 may include one or more user interfaces. In some examples, interface system 1604 may include one or more network interfaces and / or one or more external device interfaces (such as one or more Universal Serial Bus (USB) interfaces or Serial Peripheral Interface (SPI)).

[0242] In this specific embodiment, device 1600 includes display system 1610. In some such examples, display system 1610 may include layers that can be collectively referred to as a "display stack". In some examples, display system 1610 may be or may include a light-emitting diode (LED) display, such as an organic light-emitting diode (OLED) display.

[0243] Device 1600 can be used in a variety of different contexts, some of which are disclosed herein. For example, in some embodiments, a mobile device may include at least a portion of device 1600. In some embodiments, a wearable device may include at least a portion of device 1600. For example, a wearable device may be a bracelet, armband, wristband, ring, headband, or patch. In some embodiments, control system 1606 may reside in more than one device. For example, a portion of control system 1606 may reside in a wearable device, and another portion of control system 1606 may reside in another device (such as a mobile device (e.g., a smartphone)). In some such examples, interface system 1604 may also reside in more than one device.

[0244] As used in this article, the phrase “at least one of the items” refers to any combination of these items (including a single member). As an example, “at least one of a, b, or c” is intended to cover: a, b, c, ab, ac, bc, and abc.

[0245] The various exemplary logic components, logic blocks, modules, circuits, and algorithmic processes described in conjunction with the specific embodiments disclosed herein can be implemented as electronic hardware, computer software, or a combination of both. The interchangeability of hardware and software has been broadly described in terms of functionality and illustrated in the aforementioned exemplary components, blocks, modules, circuits, and processes. Whether such functionality is implemented in hardware or software depends on the specific application and the design constraints imposed on the overall system.

[0246] Hardware and data processing means for implementing the various exemplary logic units, logic blocks, modules, and circuits described in conjunction with the aspects disclosed herein can be implemented or executed using general-purpose single-chip or multi-chip processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs) or other programmable logic devices, discrete gate or transistor logic units, discrete hardware units, or any combination thereof designed to perform the functions described herein. A general-purpose processor can be a microprocessor, or any conventional processor, controller, microcontroller, or state machine. A processor can also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors cooperating with a DSP core, or any other such configuration. In some specific implementations, specific processes and methods can be performed by circuitry specific to a given function.

[0247] In one or more aspects, the described functionality may be implemented in hardware, digital electronic circuits, computer software, firmware, including the structures disclosed in this specification and their structural equivalents, or in any combination thereof. Specific embodiments of the subject matter described in this specification may also be implemented as one or more computer programs, i.e., one or more modules of computer program instructions encoded on a computer storage medium for execution by a data processing apparatus or for controlling the operation of a data processing apparatus.

[0248] If implemented in software, the functions can be stored as one or more instructions or code on or transmitted through a computer-readable medium (such as a non-transitory medium). The processes of the methods or algorithms disclosed herein can be implemented in a processor-executable software module that can reside on a computer-readable medium. Computer-readable media include both computer storage media and communication media, including any medium that can be implemented to transfer a computer program from one location to another. Storage media can be any available medium accessible to a computer. By way of example and not limitation, non-transitory media can include RAM, ROM, EEPROM, CD-ROM or other optical disc storage devices, disk storage devices or other magnetic storage devices, or any other medium that can be used to store desired program code in the form of instructions or data structures and is accessible to a computer. Furthermore, any connection can be appropriately referred to as a computer-readable medium. As used herein, disks and optical discs include compact optical discs (CDs), laser discs, optical discs, digital versatile optical discs (DVDs), floppy disks, and Blu-ray discs, where disks typically magnetically copy data, while optical discs use laser optics to copy data. Combinations of the above should also be included within the scope of computer-readable media. In addition, the operation of a method or algorithm may reside on a machine-readable medium and a computer-readable medium, or any combination thereof, as a set of code and instructions, which may be incorporated into a computer program product.

[0249] Various modifications to the specific embodiments described herein will be apparent to those skilled in the art, and the general principles defined herein may be applied to other specific embodiments without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not intended to be limited to the specific embodiments shown herein, but is to be accorded the widest scope consistent with the claims, principles, and novel features disclosed herein. The term “exemplary” is used exclusively (if any) herein to mean “serving as an example, instance, or illustration.” Any specific embodiment described herein as “exemplary” is not necessarily to be construed as superior to or better than other specific embodiments.

[0250] Certain features described in this specification in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented separately or in any suitable sub-combination in multiple embodiments. Furthermore, although features may be described above as operating in certain combinations and even initially claimed in this way, one or more features from a claimed combination may be removed from that combination in some cases, and the claimed combination may be for sub-combinations or variations thereof.

[0251] Similarly, although operations are depicted in a specific order in the figures, this should not be construed as requiring such operations to be performed in the shown specific order or sequential order, or to perform all shown operations to achieve the desired result. In some environments, multitasking and parallel processing can be advantageous. Furthermore, the separation of various system components in the embodiments described above should not be construed as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products. Additionally, other embodiments are within the scope of the following claims. In some cases, the actions described in the claims can be performed in a different order and still achieve the desired result.

[0252] It should be understood that unless features in any particular described embodiment are explicitly identified as incompatible with each other, or the surrounding context suggests that they are mutually exclusive and not readily combined in a complementary and / or supporting sense, this disclosure generally contemplates and envisions that specific features of those complementary embodiments can be selectively combined to provide one or more comprehensive but slightly different technical solutions. Therefore, it will be further appreciated that the above description is given by way of example only and can be modified in detail within the scope of this disclosure.

[0253] It should be understood that the phrases “for each of one or more <items>”, “for each of one or more <items>”, etc., when used herein, include both single-item groups and multi-item groups; that is, the phrase “for each of…” is used in the sense that it is used in programming languages ​​to refer to each item in any group of items referenced. For example, if the group of items referenced is a single item, “each” will refer only to that single item (although the fact is that the dictionary definition of “each” often defines the term as “each of two or more things”) and will not imply that at least two of those items must be present. Similarly, the terms “set” or “subset” should not by themselves be considered to necessarily cover multiple items—it should be understood that a set or subset may cover only one member or multiple members (unless the context otherwise indicates).

[0254] Terms such as “approximately,” “about,” “basically,” “nominal,” etc., when used to index quantities or similar quantifiable properties, should be understood to include values ​​within ±10% of the specified value or relation (and include the specified actual value or relation), unless otherwise specified.

[0255] Unless otherwise specified, the use of “between” should be understood to include the values ​​indicated. Thus, for example, “between A and B” should be understood to include not only values ​​greater than A and less than B (or vice versa, depending on the order of A and B), but also values ​​A and B.

[0256] In this disclosure and claims, the use of ordinal indicators (e.g., (a), (b), (c), etc.) (if any) should be understood as not conveying any particular order or sequence unless such order or sequence is explicitly indicated. For example, if there are three steps labeled (i), (ii), and (iii), it should be understood that these steps can be performed in any order (or even simultaneously, unless otherwise prohibited), unless otherwise specified. For example, if step (ii) involves processing an element created in step (i), step (ii) can be considered to occur at some point in time after step (i). Similarly, if step (i) involves processing an element created in step (ii), it should be understood that the opposite is true. It should also be understood that the use of the ordinal indicator “first” (e.g., “first item”) herein should not be interpreted as implicitly or inherently implying the necessity of a “second” instance (e.g., “second item”).

[0257] While many specific embodiments of the concepts discussed herein are apparent from the foregoing discussion and the accompanying drawings, it should be understood that this disclosure relates at least to the various specific embodiments listed in the following numbered clauses.

[0258] Clause 1: An apparatus comprising:

[0259] A first sensor pixel layer, the first sensor pixel layer including a plurality of first sensors

[0260] Pixel;

[0261] First acoustic shielding layer;

[0262] First piezoelectric layer;

[0263] Second acoustic shielding layer; and

[0264] The second sensor pixel layer includes a plurality of second sensor pixels, wherein:

[0265] The first sensor pixel layer, the first acoustic masking layer, the first piezoelectric layer, the second acoustic masking layer, and the second sensor pixel layer are arranged in a stacked configuration along the first axis.

[0266] The first acoustic masking layer includes a first high acoustic impedance (HAI) region and a first low acoustic impedance (LAI) region that repeat the first pattern.

[0267] The second acoustic masking layer includes a second HAI region and a second LAI region that repeat the second pattern.

[0268] The first HAI region has a higher acoustic impedance than the first LAI region.

[0269] The second HAI region has a higher acoustic impedance than the second LAI region.

[0270] and

[0271] When viewed along the first axis:

[0272] The first HAI region covers the second LAI region.

[0273] The second HAI region covers the first LAI region.

[0274] The first LAI region covers the second HAI region, and

[0275] The second LAI region covers the first HAI region.

[0276] Clause 2: The apparatus according to Clause 1, wherein:

[0277] When viewed along the first axis, the first LAI region is completely covered by the second HAI region, and

[0278] When viewed along the first axis, the second LAI region is completely covered by the first HAI region.

[0279] Clause 3: The apparatus according to Clause 2, wherein:

[0280] When viewed along the first axis, each first LAI region occupies a smaller area than the second HAI region that completely covers it, and

[0281] When viewed along the first axis, each second LAI region occupies a smaller area than the first HAI region that completely covers it.

[0282] Clause 4: The apparatus according to any one of Clauses 1 to 3, wherein:

[0283] Two first reference planes, perpendicular to the first axis and spaced apart by a first distance along the first axis, are defined by the opposing surfaces of the first LAI region.

[0284] The first HAI region is provided by a first gap positioned between the first reference planes, and

[0285] The first gap does not contain any solid or liquid material.

[0286] Clause 5: The apparatus according to Clause 4, wherein the first LAI region does not have the first gap.

[0287] Clause 6: The apparatus according to any one of Clauses 1 to 5, wherein:

[0288] Two second reference planes, perpendicular to the first axis and spaced a second distance apart along the first axis, are defined by opposing surfaces of the second LAI region, and

[0289] The second HAI region is provided by a second gap positioned between the second reference planes.

[0290] Clause 7: The apparatus according to Clause 6, wherein the second LAI region does not have the second gap.

[0291] Clause 8: The apparatus according to any one of Clauses 4 or 5, wherein:

[0292] Two second reference planes, perpendicular to the first axis and spaced a second distance apart along the first axis, are defined by opposing surfaces of the second LAI region.

[0293] The second HAI region is provided by a second gap positioned between the second reference planes, and

[0294] The second LAI region does not have the second gap.

[0295] Clause 9: The device according to any one of Clauses 1 to 8, wherein both the first pattern and the second pattern are checkerboard patterns.

[0296] Clause 10: The apparatus according to any one of Clauses 4 to 9, wherein each first LAI region comprises continuous material between the first reference planes.

[0297] Clause 11: The apparatus according to Clause 10, wherein the continuous material comprises copper or aluminum.

[0298] Clause 12: The apparatus according to Clause 8, wherein:

[0299] Each first LAI region includes continuous material between the first reference planes, and

[0300] Each second LAI region comprises continuous material between the second reference planes.

[0301] Clause 13: The apparatus according to Clause 12, wherein the continuous material comprises copper or aluminum.

[0302] Clause 14: The apparatus according to Clause 13, wherein:

[0303] The first LAI region of the first acoustic masking layer provides a first conductive path between the first sensor pixel layer and the first piezoelectric layer.

[0304] The second LAI region of the second acoustic masking layer provides a second conductive path between the second sensor pixel layer and the first piezoelectric layer.

[0305] Each of the first sensor pixels includes circuitry configured to electrically switch its associated first conductive path between acting as a sensor pixel electrode and acting as a first ultrasonic generator electrode.

[0306] Each of the second sensor pixels includes circuitry configured to electrically switch its associated second conductive path to switch between acting as a sensor pixel electrode and acting as a second ultrasonic generator electrode.

[0307] Clause 15: The apparatus according to Clause 14, wherein:

[0308] Each of the first LAI region and the second LAI region is electrically coupled to an electrode extension region extending into the adjacent one of the first HAI region and the second HAI region, and

[0309] Each electrode extension region in the electrode extension region provides a conductive path between the first piezoelectric layer and a first or second LAI region electrically coupled to the first piezoelectric layer.

[0310] Clause 16: The apparatus according to any one of Clauses 1 to 13 further comprises:

[0311] Second piezoelectric layer;

[0312] The third piezoelectric layer;

[0313] First sensor electrode layer; and

[0314] The second sensor electrode layer, wherein:

[0315] The first piezoelectric layer is inserted between the first sensor electrode layer and the second sensor electrode layer.

[0316] The second piezoelectric layer is inserted between the first sensor pixel layer and the first sensor electrode layer.

[0317] The third piezoelectric layer is inserted between the second sensor pixel layer and the second sensor electrode layer.

[0318] The first sensor pixel layer and the first sensor electrode layer are configured such that: the first sensor pixel measures the charge generated within the second piezoelectric layer in response to ultrasonic waves passing through it, and

[0319] The second sensor pixel layer and the second sensor electrode layer are configured such that the second sensor pixel measures the charge generated in the third piezoelectric layer in response to ultrasonic waves passing through the third piezoelectric layer.

[0320] Clause 17: The apparatus according to Clause 16 further includes:

[0321] First ultrasonic generator electrode; and

[0322] The second ultrasonic generator electrode, wherein:

[0323] The first piezoelectric layer is inserted between the first ultrasonic generator electrode and the second ultrasonic generator electrode, and

[0324] The first ultrasonic generator electrode, the second ultrasonic generator electrode, and the first piezoelectric layer are configured such that, in response to the cross-section of the first ultrasonic generator electrode and the...

[0325] The second ultrasonic generator electrode applies a potential to generate ultrasonic waves from the first piezoelectric layer. Clause 18: The apparatus according to Clause 16, wherein:

[0326] The first acoustic masking layer is inserted between the first sensor electrode layer and the first piezoelectric layer.

[0327] The second acoustic masking layer is inserted between the second sensor electrode layer and the first piezoelectric layer.

[0328] The first acoustic masking layer forms a conductive path between the first sensor electrode layer and the first piezoelectric layer, and

[0329] The second acoustic masking layer forms a conductive path between the second sensor electrode layer and the first piezoelectric layer.

[0330] Clause 19: The apparatus according to Clause 16, wherein:

[0331] The first acoustic masking layer is inserted between the first sensor electrode layer and the second piezoelectric layer.

[0332] The second acoustic masking layer is inserted between the second sensor electrode layer and the third piezoelectric layer.

[0333] The first acoustic masking layer forms a conductive path between the first sensor electrode layer and the second piezoelectric layer, and

[0334] The second acoustic masking layer forms a conductive path between the second sensor electrode layer and the third piezoelectric layer.

[0335] Clause 20: The apparatus according to any one of Clauses 1 to 19 further comprises:

[0336] First display layer;

[0337] Second display layer;

[0338] First covering glass; and

[0339] The second cover glass, wherein:

[0340] The first display layer is interposed between the first cover glass and the first sensor pixel layer.

[0341] The second display layer is interposed between the second cover glass and the second sensor pixel layer, and

[0342] Both the first display layer and the second display layer are inserted between the first cover glass and the second cover glass.

[0343] Clause 21: The apparatus according to any one of Clauses 1 to 20, wherein the apparatus is a mobile communication device.

[0344] Clause 22: A method comprising:

[0345] This causes ultrasonic waves to be generated by the first piezoelectric layer of the device;

[0346] This causes the first ultrasonic wave in the ultrasonic wave to pass through the first acoustic shielding layer of the device and propagate toward the first side of the device;

[0347] This allows the second ultrasonic wave in the ultrasonic wave to pass through the second acoustic shielding layer of the device and propagate toward the second side of the device opposite to the first side of the device;

[0348] This enables the first sensor pixel in the first sensor pixel layer of the device to obtain first fingerprint scan data based on the reflection of the first ultrasonic wave from the first side of the device;

[0349] as well as

[0350] This enables the second sensor pixel in the second sensor pixel layer of the device to obtain second fingerprint scan data based on the reflection of the second ultrasonic wave from the second side of the device, wherein:

[0351] The first sensor pixel layer, the first acoustic masking layer, the first piezoelectric layer, the second acoustic masking layer, and the second sensor pixel layer are arranged in a stacked configuration along the first axis.

[0352] The first acoustic masking layer includes a first high acoustic impedance (HAI) region and a first low acoustic impedance (LAI) region that repeat the first pattern.

[0353] The second acoustic masking layer includes a second HAI region and a second LAI region that repeat the second pattern.

[0354] The first HAI region has a higher acoustic impedance than the first LAI region.

[0355] The second HAI region has a higher acoustic impedance than the second LAI region, and

[0356] When viewed along the first axis:

[0357] The first HAI region covers the second LAI region.

[0358] The second HAI region covers the first LAI region.

[0359] The first LAI region covers the second HAI region, and

[0360] The second LAI region covers the first HAI region.

[0361] Clause 23: The method described in accordance with Clause 22, wherein:

[0362] When viewed along the first axis, the first LAI region is completely covered by the second HAI region, and

[0363] When viewed along the first axis, the second LAI region is completely covered by the first HAI region.

[0364] Clause 24: The method described in accordance with Clause 23, wherein:

[0365] When viewed along the first axis, each first LAI region occupies a smaller area than the second HAI region that completely covers it, and

[0366] When viewed along the first axis, each second LAI region occupies a smaller area than the first HAI region that completely covers it.

[0367] Clause 25: The method according to any one of Clauses 22 to 24, wherein:

[0368] Two first reference planes, perpendicular to the first axis and spaced apart by a first distance along the first axis, are defined by the opposing surfaces of the first LAI region.

[0369] The first HAI region is provided by a first gap positioned between the first reference planes, and

[0370] The first gap does not contain any solid or liquid material.

[0371] Clause 26: The method according to Clause 25, wherein the first LAI region does not have the first gap.

[0372] Clause 27: The method according to any one of Clauses 22 to 26, wherein:

[0373] Two second reference planes, perpendicular to the first axis and spaced a second distance apart along the first axis, are defined by opposing surfaces of the second LAI region, and

[0374] The second HAI region is provided by a second gap positioned between the second reference planes.

[0375] Clause 28: The method described in Clause 27, wherein the second LAI region does not have the second gap.

[0376] Clause 29: The method according to any one of Clauses 25 or 26, wherein:

[0377] Two second reference planes, perpendicular to the first axis and spaced a second distance apart along the first axis, are defined by opposing surfaces of the second LAI region.

[0378] The second HAI region is provided by a second gap positioned between the second reference planes, and

[0379] The second LAI region does not have the second gap.

[0380] Clause 30: The method according to any one of Clauses 22 to 29, wherein both the first pattern and the second pattern are chessboard patterns.

[0381] Clause 31: The method according to any one of Clauses 25 to 30, wherein each first LAI region comprises continuous material between the first reference planes.

[0382] Clause 32: The continuous material described in accordance with Clause 31 includes copper or aluminum.

[0383] Clause 33: The method described pursuant to Clause 29, wherein:

[0384] Each first LAI region includes continuous material between the first reference planes, and

[0385] Each second LAI region comprises continuous material between the second reference planes.

[0386] Clause 34: The continuous material described in accordance with Clause 33 includes copper or aluminum.

[0387] Clause 35: The method described in accordance with Clause 34, wherein:

[0388] The first LAI region of the first acoustic masking layer provides a first conductive path between the first sensor pixel layer and the first piezoelectric layer.

[0389] The second LAI region of the second acoustic masking layer provides a second conductive path between the second sensor pixel layer and the first piezoelectric layer.

[0390] Each of the first sensor pixels includes circuitry configured to electrically switch its associated first conductive path between acting as a sensor pixel electrode and acting as a first ultrasonic generator electrode.

[0391] Each of the second sensor pixels includes circuitry configured to electrically switch its associated second conductive path to switch between acting as a sensor pixel electrode and acting as a second ultrasonic generator electrode.

[0392] Clause 36: The method described pursuant to Clause 35, wherein:

[0393] Each of the first LAI region and the second LAI region is electrically coupled to an electrode extension region extending into the adjacent one of the first HAI region and the second HAI region.

[0394] Each electrode extension region in the electrode extension region provides a conductive path between the first piezoelectric layer and a first or second LAI region electrically coupled to the first piezoelectric layer.

[0395] Clause 37: The method according to any one of Clauses 22 to 34 further includes:

[0396] The reflection of the first ultrasonic wave is received in the second piezoelectric layer;

[0397] The reflection of the second ultrasonic wave is received in the third piezoelectric layer;

[0398] The first sensor pixel in the first sensor pixel layer of the device obtains first fingerprint scan data by measuring the charge generated in the second piezoelectric layer using a first sensor electrode layer; and

[0399] The second sensor pixel in the second sensor pixel layer of the device obtains second fingerprint scan data by measuring the charge generated in the third piezoelectric layer using a second sensor electrode layer, wherein:

[0400] The first piezoelectric layer is inserted between the first sensor electrode layer and the second sensor electrode layer.

[0401] The second piezoelectric layer is inserted between the first sensor pixel layer and the first sensor electrode layer.

[0402] The third piezoelectric layer is inserted between the second sensor pixel layer and the second sensor electrode layer.

[0403] The first sensor pixel layer and the first sensor electrode layer are configured such that: the first sensor pixel measures the charge generated within the second piezoelectric layer in response to ultrasonic waves passing through it, and

[0404] The second sensor pixel layer and the second sensor electrode layer are configured such that the second sensor pixel measures the charge generated in the third piezoelectric layer in response to ultrasonic waves passing through the third piezoelectric layer.

[0405] Clause 38: The method according to Clause 37, wherein generating the ultrasonic wave from the first piezoelectric layer of the device comprises applying a potential across the first piezoelectric layer by a first ultrasonic generator electrode and a second ultrasonic generator electrode, wherein:

[0406] The first piezoelectric layer is inserted between the first ultrasonic generator electrode and the second ultrasonic generator electrode.

[0407] Clause 39: The method described pursuant to Clause 37, wherein:

[0408] The first acoustic masking layer is inserted between the first sensor electrode layer and the first piezoelectric layer.

[0409] The second acoustic masking layer is inserted between the second sensor electrode layer and the first piezoelectric layer.

[0410] The first acoustic masking layer forms a conductive path between the first sensor electrode layer and the first piezoelectric layer, and

[0411] The second acoustic masking layer forms a conductive path between the second sensor electrode layer and the first piezoelectric layer.

[0412] Clause 40: The method described pursuant to Clause 37, wherein:

[0413] The first acoustic masking layer is inserted between the first sensor electrode layer and the second piezoelectric layer.

[0414] The second acoustic masking layer is inserted between the second sensor electrode layer and the third piezoelectric layer.

[0415] The first acoustic masking layer forms a conductive path between the first sensor electrode layer and the second piezoelectric layer, and

[0416] The second acoustic masking layer forms a conductive path between the second sensor electrode layer and the third piezoelectric layer.

[0417] Clause 41: The method according to any one of Clauses 22 to 40 further includes:

[0418] This allows the first graphic content to be displayed on the first display layer and through the first cover glass;

[0419] as well as

[0420] This allows the second graphic content to be displayed on the second display layer and through the second cover glass, wherein:

[0421] The first display layer is interposed between the first cover glass and the first sensor pixel layer.

[0422] The second display layer is interposed between the second cover glass and the second sensor pixel layer, and

[0423] Both the first display layer and the second display layer are inserted between the first cover glass and the second cover glass.

[0424] Clause 42: The method according to any one of Clauses 22 to 41, wherein the apparatus is a mobile communication device.

[0425] Clause 43: An apparatus comprising:

[0426] A unit used to generate one or more ultrasonic waves;

[0427] The first component used to detect the reflected ultrasonic waves;

[0428] First acoustic masking unit;

[0429] A second component for detecting the reflected ultrasonic waves; and

[0430] The second acoustic masking unit, wherein:

[0431] The unit for generating one or more ultrasonic waves, the first component for detecting the reflected ultrasonic waves, the second component for detecting the reflected ultrasonic waves, the first acoustic masking unit, and the second acoustic masking unit are arranged in a stacked configuration along a first axis.

[0432] The first acoustic masking unit includes a first high acoustic impedance (HAI) region and a first low acoustic impedance (LAI) region that repeat the first pattern.

[0433] The second acoustic masking unit includes a second HAI region and a second LAI region that repeat the second pattern.

[0434] The first HAI region has a higher acoustic impedance than the first LAI region, and the second HAI region has a higher acoustic impedance than the second LAI region.

[0435] When viewed along the first axis:

[0436] The first HAI region covers the second LAI region.

[0437] The second HAI region covers the first LAI region.

[0438] The first LAI region covers the second HAI region, and the second LAI region covers the first HAI region.

[0439] Clause 44: The apparatus according to Clause 43, wherein:

[0440] When viewed along the first axis, the first LAI region is completely covered by the second HAI region, and

[0441] When viewed along the first axis, the second LAI region is completely covered by the first HAI region.

[0442] Clause 45: The apparatus according to Clause 44, wherein:

[0443] When viewed along the first axis, each first LAI region occupies a smaller area than the second HAI region that completely covers it, and

[0444] When viewed along the first axis, each second LAI region occupies a smaller area than the first HAI region that completely covers it.

[0445] Clause 46: The apparatus according to any one of Clauses 43 to 45, wherein:

[0446] Two first reference planes, perpendicular to the first axis and spaced apart by a first distance along the first axis, are defined by the opposing surfaces of the first LAI region.

[0447] The first HAI region is provided by a first gap positioned between the first reference planes, and

[0448] The first gap does not contain any solid or liquid material.

[0449] Clause 47: The apparatus according to Clause 46, wherein the first LAI region does not have the first gap.

[0450] Clause 48: The apparatus according to any one of Clauses 43 to 47, wherein:

[0451] Two second reference planes, perpendicular to the first axis and spaced a second distance apart along the first axis, are defined by opposing surfaces of the second LAI region, and

[0452] The second HAI region is provided by a second gap positioned between the second reference planes.

[0453] Clause 49: The apparatus according to Clause 48, wherein the second LAI region does not have the second gap.

[0454] Clause 50: The apparatus pursuant to any one of Clauses 46 or 47, wherein:

[0455] Two second reference planes, perpendicular to the first axis and spaced a second distance apart along the first axis, are defined by opposing surfaces of the second LAI region.

[0456] The second HAI region is provided by a second gap positioned between the second reference planes, and

[0457] The second LAI region does not have the second gap.

[0458] Clause 51: The device according to any one of Clauses 43 to 50, wherein both the first pattern and the second pattern are checkerboard patterns.

[0459] Clause 52: The apparatus according to any one of Clauses 46 to 51, wherein each first LAI region comprises a continuous material between the first reference planes.

[0460] Clause 53: The apparatus according to Clause 52, wherein the continuous material comprises copper or aluminum.

[0461] Clause 54: The apparatus according to Clause 50, wherein:

[0462] Each first LAI region includes continuous material between the first reference planes, and

[0463] Each second LAI region comprises continuous material between the second reference planes.

[0464] Clause 55: The apparatus according to Clause 54, wherein the continuous material comprises copper or aluminum.

[0465] Clause 56: The apparatus according to Clause 55, wherein:

[0466] The first LAI region of the first acoustic masking unit provides a first conductive path between the unit for generating one or more ultrasonic waves and the first component for detecting the reflected ultrasonic waves.

[0467] The second LAI region of the second acoustic masking unit provides a second conductive path between the unit for generating one or more ultrasonic waves and the second component for detecting the reflected ultrasonic waves.

[0468] The first component for detecting reflected ultrasonic waves includes first sensor pixels, each comprising circuitry configured to electrically switch its associated first conductive path to switch between sensor pixel electrodes acting as the first component for detecting reflected ultrasonic waves and first ultrasonic generator electrodes acting as the unit for generating one or more ultrasonic waves.

[0469] The second component for detecting reflected ultrasonic waves includes a second sensor pixel, each comprising circuitry configured to electrically switch its associated second conductive path between a sensor pixel electrode serving as the second component for detecting reflected ultrasonic waves and a second ultrasonic generator electrode serving as the unit for generating one or more ultrasonic waves.

[0470] Clause 57: The apparatus according to Clause 56, wherein:

[0471] Each of the first LAI region and the second LAI region is electrically coupled to an electrode extension region extending into the adjacent one of the first HAI region and the second HAI region.

[0472] Each electrode extension region in the electrode extension region provides a conductive path between the unit for generating one or more ultrasonic waves and a first or second LAI region electrically coupled to the unit for generating one or more ultrasonic waves.

[0473] Clause 58: The apparatus according to any one of Clauses 43 to 55, wherein:

[0474] The first component for detecting reflected ultrasonic waves includes a first piezoelectric layer, a first sensor electrode layer, and a first sensor pixel layer.

[0475] The second component for detecting the reflected ultrasonic waves includes a second piezoelectric layer, a second sensor electrode layer, and a second sensor pixel layer, wherein:

[0476] The unit for generating one or more ultrasonic waves includes a third piezoelectric layer and is inserted between the first sensor electrode layer and the second sensor electrode layer.

[0477] The first piezoelectric layer is inserted between the first sensor pixel layer and the first sensor electrode layer.

[0478] The second piezoelectric layer is inserted between the second sensor pixel layer and the second sensor electrode layer.

[0479] The first sensor pixel layer and the first sensor electrode layer are configured such that: a first sensor pixel in the first sensor pixel layer measures the charge generated within the first piezoelectric layer in response to ultrasonic waves passing through it, and

[0480] The second sensor pixel layer and the second sensor electrode layer are configured such that: the second sensor pixel in the second sensor pixel layer measures the charge generated in the second piezoelectric layer in response to the passage of ultrasonic waves through the second piezoelectric layer.

[0481] Clause 59: The apparatus according to Clause 58, wherein the unit for generating one or more ultrasonic waves comprises a first ultrasonic generator electrode, a second ultrasonic generator electrode, and a third piezoelectric layer, wherein:

[0482] The third piezoelectric layer is inserted between the first ultrasonic generator electrode and the second ultrasonic generator electrode, and

[0483] The first ultrasonic generator electrode, the second ultrasonic generator electrode, and the third piezoelectric layer are configured such that ultrasonic waves are generated by the first piezoelectric layer in response to an applied potential across the first ultrasonic generator electrode and the second ultrasonic generator electrode.

[0484] Clause 60: The apparatus according to Clause 58, wherein:

[0485] The unit for generating one or more ultrasonic waves includes a third piezoelectric layer.

[0486] The first acoustic masking unit is inserted between the first sensor electrode layer and the third piezoelectric layer.

[0487] The second acoustic masking unit is inserted between the second sensor electrode layer and the third piezoelectric layer.

[0488] The first acoustic masking unit forms a conductive path between the first sensor electrode layer and the third piezoelectric layer, and

[0489] The second acoustic masking unit forms a conductive path between the second sensor electrode layer and the third piezoelectric layer.

[0490] Clause 61: The apparatus according to Clause 58, wherein:

[0491] The first acoustic masking unit is inserted between the first sensor electrode layer and the second piezoelectric layer.

[0492] The second acoustic masking unit is inserted between the second sensor electrode layer and the third piezoelectric layer.

[0493] The first acoustic masking unit forms a conductive path between the first sensor electrode layer and the first piezoelectric layer, and

[0494] The second acoustic masking unit forms a conductive path between the second sensor electrode layer and the second piezoelectric layer.

[0495] Clause 62: The apparatus according to any one of Clauses 43 to 61 further comprises:

[0496] First display component;

[0497] Second display component;

[0498] First covering component; and

[0499] The second cover component, wherein:

[0500] The first display component is inserted between the first covering component and the first component for detecting the reflected ultrasonic waves.

[0501] The second display component is inserted between the second cover component and the second component for detecting the reflected ultrasonic waves, and

[0502] Both the first display component and the second display component are inserted between the first cover component and the second cover component.

[0503] Clause 63: The apparatus pursuant to any one of Clauses 43 to 62, wherein the apparatus is a mobile communication device.

[0504] Clause 64: An apparatus comprising:

[0505] As part of a first ultrasonic fingerprint sensing system, the first ultrasonic fingerprint sensing system includes:

[0506] First sensor pixel layer,

[0507] The first piezoelectric layer, and

[0508] First electrode layer,

[0509] A part of a second ultrasonic fingerprint sensing system, the second ultrasonic fingerprint sensing system comprising:

[0510] Second sensor pixel layer,

[0511] The second piezoelectric layer, and

[0512] Second electrode layer; and

[0513] A single common controller, wherein:

[0514] The first sensor pixel layer includes a plurality of first sensor pixels, each first sensor pixel being configured to, in conjunction with the first electrode layer, measure the amount of charge generated within the first piezoelectric layer in response to ultrasonic wave transmission through the first piezoelectric layer.

[0515] The second sensor pixel layer includes a plurality of second sensor pixels, each second sensor pixel being configured to, in conjunction with the second electrode layer, measure the amount of charge generated within the second piezoelectric layer in response to ultrasonic wave transmission through the second piezoelectric layer.

[0516] At least both the first sensor pixel layer and the second sensor pixel layer are operatively connected to the single common controller.

[0517] The portion of the first fingerprint sensing system is positioned adjacent to the first side of the device.

[0518] The portion of the second fingerprint sensing system is positioned adjacent to the second side of the device opposite to the first side of the device, and

[0519] The single common controller is configured as follows:

[0520] This allows the first sensor pixel layer to obtain a fingerprint scan from the first side of the device by scanning the first sensor pixels to measure the amount of charge.

[0521] This allows the second sensor pixel layer to obtain a fingerprint scan from the second side of the device by scanning the second sensor pixels to obtain the measured charge amount.

[0522] Clause 65: The apparatus according to Clause 64, wherein the single common controller includes one or more processors and a switching element configured to switch between at least a first configuration and a second configuration, wherein:

[0523] In the first configuration, one or more first conductive paths from the first sensor pixel layer are electrically connected to the one or more processors, and one or more second conductive paths from the second sensor pixel layer are not electrically connected to the one or more processors.

[0524] In the second configuration, the one or more second conductive paths from the second sensor pixel layer are electrically connected to the one or more processors, and the one or more first conductive paths from the first sensor pixel layer are not electrically connected to the one or more processors.

[0525] The switching element is configured to switch between the first configuration and the second configuration in response to receiving one or more control signals.

[0526] Clause 66: The apparatus according to Clause 65, wherein the one or more processors is a single processor.

[0527] Clause 67: The apparatus according to Clause 65 or Clause 66, wherein the one or more processors are disposed on a single die.

[0528] Clause 68: The apparatus according to any one of Clauses 64 to 67 further comprises:

[0529] First display layer;

[0530] Second display layer;

[0531] First covering glass; and

[0532] The second cover glass, wherein:

[0533] The first display layer is interposed between the first cover glass and the first sensor pixel layer.

[0534] The second display layer is interposed between the second cover glass and the second sensor pixel layer, and

[0535] Both the first display layer and the second display layer are inserted between the first cover glass and the second cover glass.

[0536] Clause 69: A device pursuant to any one of Clauses 64 to 68, wherein the device is a mobile communication device.

[0537] Clause 70: A method comprising:

[0538] A portion of a first ultrasonic fingerprint sensing system, comprising a first sensor pixel layer, a first piezoelectric layer, and a first electrode layer, generates a first ultrasonic wave, wherein the first ultrasonic fingerprint sensing system is part of a device;

[0539] This causes a portion of a second ultrasonic fingerprint sensing system, comprising a second sensor pixel layer, a second piezoelectric layer, and a second electrode layer, to generate a second ultrasonic wave, wherein the second ultrasonic fingerprint sensing system is also part of the device; and

[0540] This enables a single common controller:

[0541] This allows the first sensor pixel in the first sensor pixel layer to measure the amount of charge generated within the first piezoelectric layer in response to the reflected portion of the first ultrasonic wave transmitting through the first piezoelectric layer.

[0542] This allows the second sensor pixel in the second sensor pixel layer to measure the amount of charge generated within the second piezoelectric layer in response to the reflected portion of the second ultrasonic wave transmitting through the second piezoelectric layer.

[0543] A fingerprint scan is obtained from the first side of the device by scanning the first sensor pixel to obtain the measured charge amount, and

[0544] A fingerprint scan is obtained from the second side of the device, opposite the first side of the device, by scanning the second sensor pixel to obtain the measured charge amount, wherein:

[0545] The first ultrasonic fingerprint sensing system and the second ultrasonic fingerprint sensing system are in the device.

[0546] At least both the first sensor pixel layer and the second sensor pixel layer are operatively connected to the single common controller.

[0547] The portion of the first fingerprint sensing system is positioned adjacent to the first side of the device, and

[0548] The portion of the second fingerprint sensing system is positioned adjacent to the second side of the device, which is opposite to the first side of the device.

[0549] Clause 71: The method according to Clause 70, wherein the single common controller comprises one or more processors and a switching element configured to switch between at least a first configuration and a second configuration, wherein:

[0550] In the first configuration, one or more first conductive paths from the first sensor pixel layer are electrically connected to the one or more processors, and one or more second conductive paths from the second sensor pixel layer are not electrically connected to the one or more processors.

[0551] In the second configuration, the one or more second conductive paths from the second sensor pixel layer are electrically connected to the one or more processors, and the one or more first conductive paths from the first sensor pixel layer are not electrically connected to the one or more processors.

[0552] The switching element is configured to switch between the first configuration and the second configuration in response to receiving one or more control signals.

[0553] Clause 72: The method described in Clause 71, wherein the one or more processors is a single processor.

[0554] Clause 73: The method described in Clause 71 or Clause 72, wherein the one or more processors are disposed on a single die.

[0555] Clause 74: The method according to any one of Clauses 70 to 73, wherein the apparatus is a mobile communication device.

[0556] Clause 75: An apparatus comprising:

[0557] A unit used to generate one or more ultrasonic waves;

[0558] The first component used to detect the reflected ultrasonic waves;

[0559] A second component for detecting the reflected ultrasonic waves; and

[0560] A single common controller, wherein:

[0561] Both the first component for detecting the reflected ultrasonic waves and the second component for detecting the reflected ultrasonic waves are operatively connected to the single common controller.

[0562] The first component for detecting the reflected ultrasonic waves is positioned adjacent to a first side of the device.

[0563] The second component for detecting the reflected ultrasonic waves is positioned adjacent to the second side of the device opposite to the first side of the device, and

[0564] The single common controller is configured as follows:

[0565] This allows the first component used to detect the reflected ultrasonic waves to obtain a fingerprint scan from the first side of the device, and

[0566] This allows the second component, used to detect the reflected ultrasonic waves, to obtain a fingerprint scan from the second side of the device.

[0567] Clause 76: The apparatus according to Clause 75, wherein the single common controller includes one or more processors and a switching element configured to switch between at least a first configuration and a second configuration, wherein:

[0568] In the first configuration, one or more first conductive paths from the first component for detecting the reflected ultrasonic waves are electrically connected to the one or more processors, and one or more second conductive paths from the second component for detecting the reflected ultrasonic waves are not electrically connected to the one or more processors.

[0569] In the second configuration, one or more second conductive paths from the second component for detecting the reflected ultrasonic waves are electrically connected to the one or more processors, and the one or more first conductive paths from the first component for detecting the reflected ultrasonic waves are not electrically connected to the one or more processors.

[0570] The switching element is configured to switch between the first configuration and the second configuration in response to receiving one or more control signals.

[0571] Clause 77: The apparatus described in Clause 76, wherein the one or more processors is a single processor.

[0572] Clause 78: The apparatus according to Clause 76 or Clause 77, wherein the one or more processors are disposed on a single die.

[0573] Clause 79: The apparatus according to any one of Clauses 75 to 78 further comprises:

[0574] First display component;

[0575] Second display component;

[0576] First covering component; and

[0577] The second cover component, wherein:

[0578] The first display component is inserted between the first covering component and the first component for detecting the reflected ultrasonic waves.

[0579] The second display component is inserted between the second cover component and the second component for detecting the reflected ultrasonic waves, and

[0580] Both the first display component and the second display component are inserted between the first cover component and the second cover component.

[0581] Clause 80: A device pursuant to any one of Clauses 75 to 79, wherein the device is a mobile communication device.

[0582] Clause 81: An apparatus comprising:

[0583] An ultrasonic fingerprint sensing system, the ultrasonic fingerprint sensing system comprising:

[0584] Sensor pixel layer,

[0585] The first piezoelectric layer, and

[0586] Electrode layer; and

[0587] Controller, wherein:

[0588] The sensor pixel layer includes a plurality of sensor pixels, each sensor pixel being configured to, in conjunction with the electrode layer, measure the amount of charge generated within the first piezoelectric layer in response to ultrasonic wave transmission through the first piezoelectric layer.

[0589] The first piezoelectric layer is positioned within the device such that a first distance between the first piezoelectric layer and a first side of the device is less than a second distance between the first piezoelectric layer and a second side of the device opposite to the first side, and the controller is configured to obtain a fingerprint scan by:

[0590] This causes the ultrasonic fingerprint sensing system to generate ultrasonic waves during a first time period that begins at the first time.

[0591] A selected delay period is chosen from a first delay period associated with the first side of the device and a second delay period that is different from the first delay period and associated with the second side of the device.

[0592] This allows the sensor pixel to measure the amount of charge generated within the first piezoelectric layer during a second time period, the second time period beginning at a second time selected at least based on the first time and the selected delay period.

[0593] The fingerprint scan is generated based on the amount of charge measured by the sensor pixels during the second time period.

[0594] Clause 82: The device according to Clause 81 further includes an acoustic conductive spacer inserted between the first piezoelectric layer and the second side of the device.

[0595] Clause 83: The device according to Clause 82 further includes an acoustically conductive compliant layer also inserted between the first piezoelectric layer and the second side of the device.

[0596] Clause 84: The apparatus according to Clause 81, wherein the first delay period is less than the second delay period.

[0597] Clause 85: The apparatus according to any one of Clauses 81 to 84 further comprises:

[0598] First display layer;

[0599] Second display layer;

[0600] First covering glass; and

[0601] The second cover glass, wherein:

[0602] The first display layer is interposed between the first cover glass and the first sensor pixel layer.

[0603] The second display layer is interposed between the second cover glass and the first sensor pixel layer.

[0604] Both the first display layer and the second display layer are inserted between the first cover glass and the second cover glass.

[0605] The first cover glass is part of the first side of the device, and the second cover glass is part of the second side of the device.

[0606] Clause 86: The apparatus according to Clause 85 further includes:

[0607] A first touch sensing system configured to detect touch input to the first cover glass; and

[0608] A second touch sensing system configured to detect touch input to the second cover glass

[0609] The system, wherein the controller is further configured to:

[0610] By combining the obtained fingerprint scan, touch input information is obtained from the first touch sensing system and the second touch sensing system.

[0611] The first delay period or the second delay period is selected as the selected delay period, at least in part, based on touch events on the first side or the second side of the device indicated by the touch input information.

[0612] Clause 87: A method comprising:

[0613] This causes the ultrasonic fingerprint sensing system of the device to generate ultrasonic waves during the first time period that begins at the first time.

[0614] A selected delay period is selected from a first delay period associated with a first side of the device and a second delay period that is different from the first delay period and associated with a second side of the device opposite to the first side of the device;

[0615] The ultrasonic fingerprint sensing system enables sensor pixels to measure the amount of charge generated within the first piezoelectric layer during a second time period, the second time period beginning at a second time selected at least based on the first time and the selected delay period; and

[0616] A fingerprint scan is generated based on the amount of charge measured by the sensor pixels of the ultrasonic fingerprint sensing system during the second time period.

[0617] Clause 88: The method according to Clause 87, wherein the ultrasonic fingerprint sensing system is separated from the second side of the device by an acoustic conductive spacer inserted between the ultrasonic fingerprint sensing system and the second side of the device.

[0618] Clause 89: The method according to Clause 88, wherein the device further comprises an acoustically conductive compliant layer also disposed between the ultrasonic fingerprint sensing system and the second side of the device.

[0619] Clause 90: The method according to Clause 87, wherein the first delay period is less than the second delay period.

[0620] Clause 91: The method according to any one of Clauses 87 to 90, wherein the apparatus further comprises:

[0621] First display layer;

[0622] Second display layer;

[0623] First covering glass; and

[0624] The second cover glass, wherein:

[0625] The first display layer is interposed between the first cover glass and the sensor pixels.

[0626] The second display layer is interposed between the second cover glass and the sensor pixels.

[0627] Both the first display layer and the second display layer are inserted between the first cover glass and the second cover glass.

[0628] The first cover glass is part of the first side of the device, and the second cover glass is part of the second side of the device.

[0629] Clause 92: The method according to Clause 91, wherein the apparatus further comprises a first touch sensing system configured to detect touch input to the first cover glass and a second touch sensing system configured to detect touch input to the second cover glass, and wherein the method further comprises:

[0630] By combining the obtained fingerprint scan, touch input information is obtained from a first touch sensing system configured to detect touch input to the first cover glass and a second touch sensing system configured to detect touch input to the second cover glass.

[0631] The first delay period or the second delay period is selected as the selected delay period, at least in part, based on touch events on the first side or the second side of the device indicated by the touch input information.

[0632] Clause 93: An apparatus comprising:

[0633] Ultrasonic fingerprint sensing unit; and

[0634] Controller, wherein:

[0635] The ultrasonic fingerprint sensing unit is positioned within the device such that a first distance between the ultrasonic fingerprint sensing unit and a first side of the device is less than a second distance between the ultrasonic fingerprint sensing unit and a second side of the device opposite to the first side of the device, and

[0636] The controller is configured to obtain a fingerprint scan by:

[0637] The ultrasonic fingerprint sensing unit generates ultrasonic waves during a first time period that begins at the first time.

[0638] A selected delay period is chosen from a first delay period associated with the first side of the device and a second delay period that is different from the first delay period and associated with the second side of the device.

[0639] This allows the ultrasonic fingerprint sensing unit to acquire a fingerprint scan during a second time period, the second time period starting at a second time selected based at least on the first time and the selected delay period.

[0640] Clause 94: The apparatus according to Clause 93 further includes an acoustic conductive spacer inserted between the ultrasonic fingerprint sensing unit and the second side of the apparatus.

[0641] Clause 95: The device according to Clause 94 further includes an acoustically conductive compliance layer also disposed between the ultrasonic fingerprint sensing unit and the second side of the device.

[0642] Clause 96: The apparatus according to Clause 93, wherein the first delay period is less than the second delay period.

[0643] Clause 97: The apparatus according to any one of Clauses 93 to 96 further comprises:

[0644] First display component;

[0645] Second display component;

[0646] First covering component; and

[0647] The second cover component, wherein:

[0648] The first display component is inserted between the first cover component and the ultrasonic fingerprint detection unit.

[0649] The second display component is inserted between the second cover component and the ultrasonic fingerprint sensing unit.

[0650] Both the first display component and the second display component are inserted between the first cover component and the second cover component.

[0651] The first covering component is part of the first side of the device, and

[0652] The second covering component is part of the second side of the device.

[0653] Clause 98: The apparatus according to Clause 97 further includes:

[0654] A first touch sensing unit configured to detect touch input to the first covering component; and

[0655] A second touch sensing unit configured to detect touch input to the second covering component, wherein the controller is further configured to:

[0656] By combining the obtained fingerprint scan, touch input information is obtained from the first touch sensing unit and the second touch sensing unit.

[0657] The first delay period or the second delay period is selected as the selected delay period, at least in part, based on touch events on the first side or the second side of the device indicated by the touch input information.

[0658] Clause 99: A non-transitory computer-readable medium storing computer-executable instructions, which, when executed by one or more processors, cause the one or more processors to:

[0659] This causes ultrasonic waves to be generated by the first piezoelectric layer of the device;

[0660] This causes the first ultrasonic wave in the ultrasonic wave to pass through the first acoustic shielding layer of the device and propagate toward the first side of the device;

[0661] This allows the second ultrasonic wave in the ultrasonic wave to pass through the second acoustic shielding layer of the device and propagate toward the second side of the device opposite to the first side of the device;

[0662] This enables the first sensor pixel in the first sensor pixel layer of the device to obtain first fingerprint scan data based on the reflection of the first ultrasonic wave from the first side of the device;

[0663] as well as

[0664] This enables the second sensor pixel in the second sensor pixel layer of the device to obtain second fingerprint scan data based on the reflection of the second ultrasonic wave from the second side of the device, wherein in the device:

[0665] The first sensor pixel layer, the first acoustic masking layer, the first piezoelectric layer, the second acoustic masking layer, and the second sensor pixel layer are arranged in a stacked configuration along the first axis.

[0666] The first acoustic masking layer includes a first high acoustic impedance (HAI) region and a first low acoustic impedance (LAI) region that repeat the first pattern.

[0667] The second acoustic masking layer includes a second HAI region and a second LAI region that repeat the second pattern.

[0668] The first HAI region has a higher acoustic impedance than the first LAI region, and the second HAI region has a higher acoustic impedance than the second LAI region.

[0669] and

[0670] When viewed along the first axis:

[0671] The first HAI region covers the second LAI region.

[0672] The second HAI region covers the first LAI region.

[0673] The first LAI region covers the second HAI region, and

[0674] The second LAI region covers the first HAI region.

[0675] Clause 100: A non-transitory computer-readable medium as described in Clause 99, wherein in said apparatus:

[0676] When viewed along the first axis, the first LAI region is completely covered by the second HAI region, and

[0677] When viewed along the first axis, the second LAI region is completely covered by the first HAI region.

[0678] Clause 101: A non-transitory computer-readable medium according to Clause 100, wherein in said apparatus:

[0679] When viewed along the first axis, each first LAI region occupies a smaller area than the second HAI region that completely covers it, and

[0680] When viewed along the first axis, each second LAI region occupies a smaller area than the first HAI region that completely covers it.

[0681] Clause 102: A non-transitory computer-readable medium according to any one of Clauses 99 to 101, wherein in said apparatus:

[0682] Two first reference planes, perpendicular to the first axis and spaced apart by a first distance along the first axis, are defined by the opposing surfaces of the first LAI region.

[0683] The first HAI region is provided by a first gap positioned between the first reference planes, and

[0684] The first gap does not contain any solid or liquid material.

[0685] Clause 103: A non-transitory computer-readable medium according to Clause 102, wherein in the device, the first LAI region does not have the first gap.

[0686] Clause 104: A non-transitory computer-readable medium according to any one of Clauses 99 to 103, wherein in said apparatus:

[0687] Two second reference planes, perpendicular to the first axis and spaced a second distance apart along the first axis, are defined by opposing surfaces of the second LAI region, and

[0688] The second HAI region is provided by a second gap positioned between the second reference planes.

[0689] Clause 105: A non-transitory computer-readable medium as described in Clause 104, wherein in the device, the second LAI region does not have the second gap.

[0690] Clause 106: A non-transitory computer-readable medium as described in Clause 103 or Clause 104, wherein in said apparatus:

[0691] Two second reference planes, perpendicular to the first axis and spaced a second distance apart along the first axis, are defined by opposing surfaces of the second LAI region.

[0692] The second HAI region is provided by a second gap positioned between the second reference planes, and

[0693] The second LAI region does not have the second gap.

[0694] Clause 107: A non-transitory computer-readable medium according to any one of Clauses 99 to 106, wherein, in the device, both the first pattern and the second pattern are chessboard patterns.

[0695] Clause 108: A non-transitory computer-readable medium according to any one of Clauses 102 to 107, wherein in the apparatus, each first LAI region comprises continuous material between the first reference planes.

[0696] Clause 109: A non-transitory computer-readable medium as described in Clause 108, wherein in the apparatus, the continuous material comprises copper or aluminum.

[0697] Clause 110: A non-transitory computer-readable medium as described in Clause 107, wherein in said apparatus:

[0698] Each first LAI region includes continuous material between the first reference planes, and

[0699] Each second LAI region comprises continuous material between the second reference planes.

[0700] Clause 111: A non-transitory computer-readable medium as described in Clause 110, wherein in the device, the continuous material comprises copper or aluminum.

[0701] Clause 112: A non-transitory computer-readable medium as described in Clause 111, wherein in said apparatus:

[0702] The first LAI region of the first acoustic masking layer provides a first conductive path between the first sensor pixel layer and the first piezoelectric layer.

[0703] The second LAI region of the second acoustic masking layer provides a second conductive path between the second sensor pixel layer and the first piezoelectric layer.

[0704] Each of the first sensor pixels includes circuitry configured to electrically switch its associated first conductive path between acting as a sensor pixel electrode and acting as a first ultrasonic generator electrode.

[0705] Each of the second sensor pixels includes circuitry configured to electrically switch its associated second conductive path to switch between acting as a sensor pixel electrode and acting as a second ultrasonic generator electrode.

[0706] Clause 113: A non-transitory computer-readable medium as described in Clause 112, wherein in said apparatus:

[0707] Each of the first LAI region and the second LAI region is electrically coupled to an electrode extension region extending into the adjacent one of the first HAI region and the second HAI region.

[0708] Each electrode extension region in the electrode extension region provides a conductive path between the first piezoelectric layer and a first or second LAI region electrically coupled to the first piezoelectric layer.

[0709] Clause 114: A non-transitory computer-readable medium according to any one of Clauses 99 to 112, wherein the non-transitory computer-readable medium further stores additional computer-executable instructions, which, when executed by the one or more processors, cause the one or more processors to:

[0710] The reflection of the first ultrasonic wave is received in the second piezoelectric layer;

[0711] The reflection of the second ultrasonic wave is received in the third piezoelectric layer;

[0712] The device enables the first sensor pixel in the first sensor pixel layer to obtain the first fingerprint scan data by measuring the charge generated in the second piezoelectric layer using the first sensor electrode layer; and

[0713] The second sensor pixel in the second sensor pixel layer of the device obtains the second fingerprint scan data by measuring the charge generated in the third piezoelectric layer using the second sensor electrode layer, wherein in the device:

[0714] The first piezoelectric layer is inserted between the first sensor electrode layer and the second sensor electrode layer.

[0715] The second piezoelectric layer is inserted between the first sensor pixel layer and the first sensor electrode layer.

[0716] The third piezoelectric layer is inserted between the second sensor pixel layer and the second sensor electrode layer.

[0717] The first sensor pixel layer and the first sensor electrode layer are configured such that: the first sensor pixel measures the charge generated within the second piezoelectric layer in response to ultrasonic waves passing through it, and

[0718] The second sensor pixel layer and the second sensor electrode layer are configured such that the second sensor pixel measures the charge generated in the third piezoelectric layer in response to ultrasonic waves passing through the third piezoelectric layer.

[0719] Clause 115: A non-transitory computer-readable medium according to Clause 114, wherein the computer-executable instructions causing the first piezoelectric layer of the device to generate the ultrasonic waves include computer-executable instructions causing the one or more processors to apply a potential across the first piezoelectric layer by a first ultrasonic generator electrode and a second ultrasonic generator electrode, wherein in the device, the first piezoelectric layer is interposed between the first ultrasonic generator electrode and the second ultrasonic generator electrode.

[0720] Clause 116: A non-transitory computer-readable medium as described in Clause 114, wherein in said apparatus:

[0721] The first acoustic masking layer is inserted between the first sensor electrode layer and the first piezoelectric layer.

[0722] The second acoustic masking layer is inserted between the second sensor electrode layer and the first piezoelectric layer.

[0723] The first acoustic masking layer forms a conductive path between the first sensor electrode layer and the first piezoelectric layer, and

[0724] The second acoustic masking layer forms a conductive path between the second sensor electrode layer and the first piezoelectric layer.

[0725] Clause 117: A non-transitory computer-readable medium as described in Clause 114, wherein in said apparatus:

[0726] The first acoustic masking layer is inserted between the first sensor electrode layer and the second piezoelectric layer.

[0727] The second acoustic masking layer is inserted between the second sensor electrode layer and the third piezoelectric layer.

[0728] The first acoustic masking layer forms a conductive path between the first sensor electrode layer and the second piezoelectric layer, and

[0729] The second acoustic masking layer forms a conductive path between the second sensor electrode layer and the third piezoelectric layer.

[0730] Clause 118: A non-transitory computer-readable medium according to any one of Clauses 99 to 117, wherein the non-transitory computer-readable medium further stores additional computer-executable instructions, which, when executed by the one or more processors, also cause the one or more processors to:

[0731] This allows the first graphic content to be displayed on the first display layer and through the first cover glass;

[0732] as well as

[0733] This allows the second graphic content to be displayed on the second display layer and through the second cover glass, wherein in the device:

[0734] The first display layer is interposed between the first cover glass and the first sensor pixel layer.

[0735] The second display layer is interposed between the second cover glass and the second sensor pixel layer, and

[0736] Both the first display layer and the second display layer are inserted between the first cover glass and the second cover glass.

[0737] Clause 119: A non-transitory computer-readable medium pursuant to any one of Clauses 99 to 118, wherein the means is a mobile communication device.

[0738] Clause 120: A non-transitory computer-readable medium storing computer-executable instructions, which, when executed by one or more processors, cause the one or more processors to:

[0739] A portion of a first ultrasonic fingerprint sensing system, comprising a first sensor pixel layer, a first piezoelectric layer, and a first electrode layer, generates a first ultrasonic wave, wherein the first ultrasonic fingerprint sensing system is part of a device;

[0740] This causes a portion of a second ultrasonic fingerprint sensing system, comprising a second sensor pixel layer, a second piezoelectric layer, and a second electrode layer, to generate a second ultrasonic wave, wherein the second ultrasonic fingerprint sensing system is also part of the device; and

[0741] This enables a single common controller:

[0742] This allows the first sensor pixel in the first sensor pixel layer to measure the amount of charge generated within the first piezoelectric layer in response to the reflected portion of the first ultrasonic wave transmitting through the first piezoelectric layer.

[0743] This allows the second sensor pixel in the second sensor pixel layer to measure the amount of charge generated within the second piezoelectric layer in response to the reflected portion of the second ultrasonic wave transmitting through the second piezoelectric layer.

[0744] A fingerprint scan is obtained from the first side of the device by scanning the first sensor pixel to obtain the measured charge amount, and

[0745] A fingerprint scan is obtained from the second side of the device, opposite the first side of the device, by scanning the second sensor pixel to obtain the measured charge amount, wherein:

[0746] The first ultrasonic fingerprint sensing system and the second ultrasonic fingerprint sensing system are in the device.

[0747] At least both the first sensor pixel layer and the second sensor pixel layer are operatively connected to the single common controller.

[0748] The portion of the first fingerprint sensing system is positioned adjacent to the first side of the device, and

[0749] The portion of the second fingerprint sensing system is positioned adjacent to the second side of the device, which is opposite to the first side of the device.

[0750] Clause 121: The non-transitory computer-readable medium according to Clause 120, wherein the single common controller comprises one or more processors and switching elements configured to switch between at least a first configuration and a second configuration, wherein:

[0751] In the first configuration, one or more first conductive paths from the first sensor pixel layer are electrically connected to the one or more processors, and one or more second conductive paths from the second sensor pixel layer are not electrically connected to the one or more processors.

[0752] In the second configuration, the one or more second conductive paths from the second sensor pixel layer are electrically connected to the one or more processors, and the one or more first conductive paths from the first sensor pixel layer are not electrically connected to the one or more processors.

[0753] The switching element is configured to switch between the first configuration and the second configuration in response to receiving one or more control signals, and

[0754] The non-transitory computer-readable medium also stores additional computer-executable instructions, which, when executed by the one or more processors, cause the one or more processors to: send the one or more control signals to the switching element.

[0755] Clause 122: A non-transitory computer-readable medium as described in Clause 121, wherein the one or more processors is a single processor.

[0756] Clause 123: A nontransitory computer-readable medium as described in Clause 121 or Clause 122, wherein one or more processors are disposed on a single die.

[0757] Clause 124: A non-transitory computer-readable medium according to any one of Clauses 120 to 123, wherein the means is a mobile communication device.

[0758] Clause 125: A non-transitory computer-readable medium storing computer-executable instructions, which, when executed by one or more processors, cause the one or more processors to:

[0759] This causes the ultrasonic fingerprint sensing system of the device to generate ultrasonic waves during the first time period that begins at the first time.

[0760] A selected delay period is selected from a first delay period associated with a first side of the device and a second delay period that is different from the first delay period and associated with a second side of the device opposite to the first side of the device;

[0761] The ultrasonic fingerprint sensing system enables sensor pixels to measure the amount of charge generated within the first piezoelectric layer during a second time period, the second time period beginning at a second time selected at least based on the first time and the selected delay period; and

[0762] A fingerprint scan is generated based on the amount of charge measured by the sensor pixels of the ultrasonic fingerprint sensing system during the second time period.

[0763] Clause 126: A non-transitory computer-readable medium according to Clause 125, wherein in the device, the ultrasonic fingerprint sensing system is separated from the second side of the device by an acoustic conductive spacer inserted between the ultrasonic fingerprint sensing system and the second side of the device.

[0764] Clause 127: A non-transitory computer-readable medium as described in Clause 126, wherein the device further includes an acoustically conductive compliance layer also disposed between the ultrasonic fingerprint sensing system and the second side of the device.

[0765] Clause 128: A non-transitory computer-readable medium as described in Clause 125, wherein the first delay period is less than the second delay period.

[0766] Clause 129: A non-transitory computer-readable medium according to any one of Clauses 125 to 128, wherein said means further comprises:

[0767] First display layer;

[0768] Second display layer;

[0769] First covering glass; and

[0770] The second cover glass, wherein:

[0771] The first display layer is interposed between the first cover glass and the sensor pixels.

[0772] The second display layer is interposed between the second cover glass and the sensor pixels.

[0773] Both the first display layer and the second display layer are inserted between the first cover glass and the second cover glass.

[0774] The first cover glass is part of the first side of the device, and the second cover glass is part of the second side of the device.

[0775] Clause 130: A non-transitory computer-readable medium according to Clause 129, wherein the apparatus further comprises a first touch sensing system configured to detect touch input to the first cover glass and a second touch sensing system configured to detect touch input to the second cover glass, and wherein the non-transitory computer-readable medium further stores additional computer-executable instructions, which, when executed by the one or more processors, cause the one or more processors to:

[0776] By combining the obtained fingerprint scan, touch input information is obtained from a first touch sensing system configured to detect touch input to the first cover glass and a second touch sensing system configured to detect touch input to the second cover glass.

[0777] The first delay period or the second delay period is selected as the selected delay period, at least in part, based on touch events on the first side or the second side of the device indicated by the touch input information.

Claims

1. A device for ultrasonic fingerprint sensing, the device comprising: As part of a first ultrasonic fingerprint sensing system, the first ultrasonic fingerprint sensing system includes: First sensor pixel layer, The first piezoelectric layer, and First electrode layer, A part of a second ultrasonic fingerprint sensing system, the second ultrasonic fingerprint sensing system comprising: Second sensor pixel layer, The second piezoelectric layer, and Second electrode layer; and A single common controller, wherein: The first sensor pixel layer includes a plurality of first sensor pixels, each first sensor pixel being configured to, in conjunction with the first electrode layer, measure the amount of charge generated within the first piezoelectric layer in response to ultrasonic wave transmission through the first piezoelectric layer. The second sensor pixel layer includes a plurality of second sensor pixels, each second sensor pixel being configured to, in conjunction with the second electrode layer, measure the amount of charge generated within the second piezoelectric layer in response to ultrasonic wave transmission through the second piezoelectric layer. At least both the first sensor pixel layer and the second sensor pixel layer are operatively connected to the single common controller. The portion of the first ultrasonic fingerprint sensing system is positioned adjacent to the first side of the device. The portion of the second ultrasonic fingerprint sensing system is positioned adjacent to the second side of the device, which is opposite to the first side of the device. The single common controller includes one or more processors and switching elements configured to switch between at least a first configuration and a second configuration, wherein: In the first configuration, one or more first conductive paths from the first sensor pixel layer are electrically connected to the one or more processors, and one or more second conductive paths from the second sensor pixel layer are not electrically connected to the one or more processors. The single common controller is configured such that the first sensor pixel layer obtains a fingerprint scan from the first side of the device by scanning the first sensor pixels to obtain the measured charge amount. In the second configuration, the one or more second conductive paths from the second sensor pixel layer are electrically connected to the one or more processors, and the one or more first conductive paths from the first sensor pixel layer are not electrically connected to the one or more processors. The single common controller is configured such that the second sensor pixel layer obtains a fingerprint scan from the second side of the device by scanning the second sensor pixels to obtain the measured charge amount, and The switching element is configured to switch between a first configuration and a second configuration in response to receiving one or more control signals, the one or more control signals indicating that no valid fingerprint scan was obtained from the first side or that fewer than the expected number of fingerprint scans were obtained from the first side.

2. The apparatus of claim 1, wherein the single common controller is configured to cycle and rapidly switch between the first configuration and the second configuration.

3. The apparatus of claim 2, wherein the single common controller is configured to cycle between the first configuration and the second configuration at intervals of 100 ms or less.

4. The apparatus of claim 1, wherein the one or more processors is a single processor.

5. The apparatus of claim 1, wherein the one or more processors are disposed on a single die.

6. The apparatus according to claim 1, further comprising: First display layer; Second display layer; First covering glass; and The second cover glass, wherein: The first display layer is interposed between the first cover glass and the first sensor pixel layer. The second display layer is interposed between the second cover glass and the second sensor pixel layer, and Both the first display layer and the second display layer are inserted between the first cover glass and the second cover glass.

7. The apparatus according to claim 6, further comprising a first touch sensing system and a second touch sensing system, wherein: The first display layer is interposed between the first touch sensing system and the first sensor pixel layer, and The second display layer is interposed between the second touch sensing system and the second sensor pixel layer.

8. The apparatus of claim 7, wherein at least one of the first touch sensing system and the second touch sensing system is a capacitive touch sensor.

9. The apparatus according to claim 1, wherein the apparatus is a mobile communication device.

10. A method for ultrasonic fingerprint sensing, the method comprising: A portion of a first ultrasonic fingerprint sensing system, comprising a first sensor pixel layer, a first piezoelectric layer, and a first electrode layer, generates a first ultrasonic wave, wherein the first ultrasonic fingerprint sensing system is part of a device; A portion of a second ultrasonic fingerprint sensing system, comprising a second sensor pixel layer, a second piezoelectric layer, and a second electrode layer, generates a second ultrasonic wave, wherein the second ultrasonic fingerprint sensing system is also part of the device. as well as This results in a single common controller comprising one or more processors and switching elements configured to switch between at least a first configuration and a second configuration: This allows the first sensor pixel in the first sensor pixel layer to measure the amount of charge generated within the first piezoelectric layer in response to the reflected portion of the first ultrasonic wave transmitting through the first piezoelectric layer. This allows the second sensor pixel in the second sensor pixel layer to measure the amount of charge generated within the second piezoelectric layer in response to the reflected portion of the second ultrasonic wave transmitting through the second piezoelectric layer. In the first configuration, one or more first conductive paths from the first sensor pixel layer are electrically connected to the one or more processors, and one or more second conductive paths from the second sensor pixel layer are not electrically connected to the one or more processors. A fingerprint scan is obtained from a first side of the device by scanning the first sensor pixels to obtain a measured charge quantity. In the second configuration, the one or more second conductive paths from the second sensor pixel layer are electrically connected to the one or more processors, and the one or more first conductive paths from the first sensor pixel layer are not electrically connected to the one or more processors. A fingerprint scan is obtained from the second side of the device, opposite the first side of the device, by scanning the second sensor pixels to obtain the measured charge amount. The switching element is configured to switch between a first configuration and a second configuration in response to receiving one or more control signals, the one or more control signals indicating that no valid fingerprint scan was obtained from the first side or that fewer than the expected number of fingerprint scans were obtained from the first side. in: The first ultrasonic fingerprint sensing system and the second ultrasonic fingerprint sensing system are in the device. At least both the first sensor pixel layer and the second sensor pixel layer are operatively connected to the single common controller. The portion of the first ultrasonic fingerprint sensing system is positioned adjacent to the first side of the device, and The portion of the second ultrasonic fingerprint sensing system is positioned adjacent to the second side of the device, which is opposite to the first side of the device.

11. The method of claim 10, wherein the method further comprises causing the single common controller to cycle and rapidly switch between the first configuration and the second configuration.

12. The method of claim 11, wherein the method further comprises causing the single common controller to cycle between the first configuration and the second configuration at intervals of 100 ms or less.

13. The method of claim 10, wherein the one or more processors is a single processor.

14. The method of claim 10, wherein the one or more processors are disposed on a single die.

15. The method of claim 10, wherein: The first ultrasonic fingerprint sensing system further includes a first cover glass and a first display layer inserted between the first cover glass and the first sensor pixel layer. The second ultrasonic fingerprint sensing system further includes a second cover glass and a second display layer inserted between the second cover glass and the second sensor pixel layer. Both the first display layer and the second display layer are inserted between the first cover glass and the second cover glass.

16. The method of claim 10, wherein the first ultrasonic fingerprint sensing system further comprises a first touch sensing system and the second ultrasonic fingerprint sensing system further comprises a second touch sensing system, wherein: The first display layer is interposed between the first touch sensing system and the first sensor pixel layer, and The second display layer is interposed between the second touch sensing system and the second sensor pixel layer.

17. The method of claim 16, wherein at least one of the first touch sensing system and the second touch sensing system is a capacitive touch sensor.

18. The method of claim 10, wherein the apparatus is a mobile communication device.

19. An apparatus for ultrasonic fingerprint sensing, the apparatus comprising components for performing the method according to any one of claims 10-18.

20. A computer-readable medium having program code recorded thereon, wherein the program code is executable by one or more processors of a device to cause the processor to perform the method according to any one of claims 10-18.

21. A computer program product comprising computer-readable instructions, which, when executed by a processor, cause the processor to perform the method according to any one of claims 10-18.

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