Abstract: Some disclosed examples involve receiving ultrasonic receiver signals from an ultrasonic receiver system corresponding to ultrasonic waves generated by a target object responsive to light from a light source system, estimating one or more blood vessel features based, at least in part, on the ultrasonic receiver signals and estimating blood pressure based, at least in part, on the one or more blood vessel features. Some disclosed examples involve receiving inertial sensor data from an inertial sensor system, determining whether the inertial sensor data indicates apparatus motion that exceeds a threshold and controlling a photoacoustic plethysmography (PAPG) system that includes the light source system and the ultrasonic receiver system according to whether the apparatus motion exceeds the threshold.

Abstract: Some disclosed examples pertain to an apparatus that can include a platen, a light source system, a receiver system, and an electromagnetic interference (EMI) shield. The light source system can include light source system circuitry, a light-emitting component, and a light guide component having a substantially uniform cross-section. The light-emitting component provides light to an area of the platen via the light guide component. The receiver system can include at least two receiver stack portions residing proximate on either side of the light guide component. The receiver system detects acoustic waves corresponding to a photoacoustic response of a target object proximate the area of the platen, to light emitted by the light source system. The EMI shield shields the receiver system from at least some of the EMI produced by the light source system circuitry. The light guide component conveys light through a portion of the EMI shield.

Abstract: An apparatus may include a platen, a light source system and a receiver system. The light source system may at least a first light-emitting component and at least a first light guide component. The first light guide component may be configured to transmit light from the first light-emitting component towards a target object in contact with a first area of the platen. The receiver system may include at least two receiver stack portions. A first receiver stack portion may reside proximate a first side of a first portion of the first light guide component and a second receiver stack portion may reside proximate a second side of the first portion of the first light guide component. The receiver system may be configured to detect acoustic waves corresponding to a photoacoustic response of the target object to light emitted by the light source system.

Abstract: Some disclosed examples pertain to an apparatus that can include a platen, a light source system, a receiver system, and an electromagnetic interference (EMI) shield. The light source system can include light source system circuitry, a light-emitting component, and a light guide component having a substantially uniform cross-section. The light-emitting component provides light to an area of the platen via the light guide component. The receiver system can include at least two receiver stack portions residing proximate on either side of the light guide component. The receiver system detects acoustic waves corresponding to a photoacoustic response of a target object proximate the area of the platen, to light emitted by the light source system. The EMI shield shields the receiver system from at least some of the EMI produced by the light source system circuitry. The light guide component conveys light through a portion of the EMI shield.

Abstract: Some disclosed implementations include an ultrasonic sensor stack and an acoustic resonator. The acoustic resonator may be configured to enhance ultrasonic waves transmitted by the ultrasonic sensor stack in an ultrasonic frequency range that is suitable for ultrasonic fingerprint sensors. In some examples, the acoustic resonator may include one or more low-impedance layers residing between a first higher-impedance layer and a second higher-impedance layer. Each of the one or more low-impedance layers may have a lower acoustic impedance than an acoustic impedance of the first higher-impedance layer or an acoustic impedance of the second higher-impedance layer. At least one low-impedance layer may have a thickness corresponding to a multiple of a half wavelength at a peak frequency of the acoustic resonator. The peak frequency may be within a frequency range from 1 MHz. to 20 MHz.

Abstract: Some disclosed implementations include an ultrasonic sensor stack and an acoustic resonator. The acoustic resonator may be configured to enhance ultrasonic waves transmitted by the ultrasonic sensor stack in an ultrasonic frequency range that is suitable for ultrasonic fingerprint sensors. In some examples, the acoustic resonator may include one or more low-impedance layers residing between a first higher-impedance layer and a second higher-impedance layer. Each of the one or more low-impedance layers may have a lower acoustic impedance than an acoustic impedance of the first higher-impedance layer or an acoustic impedance of the second higher-impedance layer. At least one low-impedance layer may have a thickness corresponding to a multiple of a half wavelength at a peak frequency of the acoustic resonator. The peak frequency may be within a frequency range from 1 MHz. to 20 MHz.

Abstract: Some disclosed examples pertain to an apparatus that can include a platen, a light source system, a receiver system, and an electromagnetic interference (EMI) shield. The light source system can include light source system circuitry, a light-emitting component, and a light guide component having a substantially uniform cross-section. The light-emitting component provides light to an area of the platen via the light guide component. The receiver system can include at least two receiver stack portions residing proximate on either side of the light guide component. The receiver system detects acoustic waves corresponding to a photoacoustic response of a target object proximate the area of the platen, to light emitted by the light source system. The EMI shield shields the receiver system from at least some of the EMI produced by the light source system circuitry. The light guide component conveys light through a portion of the EMI shield.

Abstract: An apparatus may include a platen, a light source system, an ultrasonic receiver system and a control system, the light source system being configured for providing first light and second light having first and second wavelengths to a target object on an outer surface of the platen and including one or more light guides configured to convey light parallel to a surface of the platen. The control system may be configured to: cause the light source system to provide the first light and the second light to the target object at a first time and a second time, respectively; receive first and second ultrasonic receiver signals from the ultrasonic receiver system corresponding to photoacoustic responses of the target object to the first light and the second light, respectively; and estimate one or more blood vessel features based on at least one of the first or the second ultrasonic receiver signals.

Abstract: Some disclosed examples involve receiving ultrasonic receiver signals from an ultrasonic receiver system corresponding to ultrasonic waves generated by a target object responsive to light from a light source system, estimating one or more blood vessel features based, at least in part, on the ultrasonic receiver signals and estimating blood pressure based, at least in part, on the one or more blood vessel features. Some disclosed examples involve receiving inertial sensor data from an inertial sensor system, determining whether the inertial sensor data indicates apparatus motion that exceeds a threshold and controlling a photoacoustic plethysmography (PAPG) system that includes the light source system and the ultrasonic receiver system according to whether the apparatus motion exceeds the threshold.

Abstract: An apparatus may include a platen, a light source system, an ultrasonic receiver system and a control system, the light source system configured for providing first light of a first wavelength and second light of a second wavelength to a target object along a first axis. The control system may be configured to: cause the light source system to provide the first light to the target object at a first time and to provide the second light to the target object at a second time; receive first ultrasonic receiver signals and second ultrasonic receiver signals from the ultrasonic receiver system corresponding to photoacoustic responses of the target object to the first light and the second light, respectively; and estimate one or more blood vessel features based on at least one of the first ultrasonic receiver signals or the second ultrasonic receiver signals.

Abstract: Some disclosed examples involve controlling a light-steering system to direct light emitted by at least a first light source of a light source system to a first plurality of areas of a target object, wherein controlling the light-steering system involves controlling one or more adjustable micromirrors, one or more adjustable lenses, one or more adjustable diffraction gratings, or combinations thereof. Some examples involve receiving ultrasonic receiver signals from an ultrasonic receiver system corresponding to photoacoustic responses of the target object to light provided the light source system to each area of the first plurality of areas and determining a selected area of the target object from which additional ultrasonic receiver signals will be obtained, wherein determining the selected area involves detecting a blood vessel within the target object. Some examples involve controlling the light source system to obtain additional ultrasonic receiver signals from the selected area.

Abstract: Some disclosed methods may involve providing first light of a first wavelength to a target object at a first time, receiving first ultrasonic receiver signals from an ultrasonic receiver system corresponding to photoacoustic responses of the target object to the first light, providing second light of a second wavelength to the target object at a second time, receiving second ultrasonic receiver signals from the ultrasonic receiver system corresponding to photoacoustic responses of the target object to the second light and differentiating a desired signal from one or more background signals based, at least in part, on the first ultrasonic receiver signals and the second ultrasonic receiver signals. The desired signal may correspond to at least a portion of a blood vessel within the target object. A light source system may be configured for providing the first light and the second light to the target object along the same axis.

Abstract: An apparatus may include a platen, a light source system, an ultrasonic receiver system and a control system, the light source system configured for providing first light of a first wavelength and second light of a second wavelength to a target object on an outer surface of the platen. The control system may be configured to: cause the light source system to provide the first light to the target object at a first time and to provide the second light to the target object at a second time; receive first ultrasonic receiver signals and second ultrasonic receiver signals from the ultrasonic receiver system corresponding to photoacoustic responses of the target object to the first light and the second light, respectively; and estimate one or more blood vessel features based on at least one of the first ultrasonic receiver signals or the second ultrasonic receiver signals.

Abstract: An apparatus may include a platen, a light source system and a receiver system. The light source system may at least a first light-emitting component and at least a first light guide component. The first light guide component may be configured to transmit light from the first light-emitting component towards a target object in contact with a first area of the platen. The receiver system may include at least two receiver stack portions. A first receiver stack portion may reside proximate a first side of a first portion of the first light guide component and a second receiver stack portion may reside proximate a second side of the first portion of the first light guide component. The receiver system may be configured to detect acoustic waves corresponding to a photoacoustic response of the target object to light emitted by the light source system.

Abstract: An apparatus may include a platen, a light source system and an ultrasonic receiver system. The light source system may be configured to provide light to a target object on an outer surface of the platen. The light source system may be configured to direct the light along a first axis oriented at a first angle relative to the outer surface of the platen. The ultrasonic receiver system may be configured to receive ultrasonic waves generated by the target object responsive to the light from the light source system. The ultrasonic receiver system may include one or more receiver elements residing in a receiver plane. A normal to the receiver plane being may be oriented along a second axis at a second angle relative to the outer surface of the platen. The first angle may be different from the second angle.

Abstract: An apparatus may include a substrate, a light source system and a receiver system. The light source system may be configured to emit light through an area of the substrate, from a first side of the substrate towards a target object in contact with a second and opposite side of the substrate. The receiver system may include one or more receivers residing in, on or proximate the substrate. The receiver system may be configured to detect surface acoustic waves propagating in the substrate corresponding to a photoacoustic response of the target object to light emitted by the light source system. In some examples, the apparatus may include a control system. The control system may be configured to receive surface acoustic wave signals from the receiver system corresponding to detected surface acoustic waves and to detect at least one structure within the target object based on the surface acoustic wave signals.

Abstract: Some disclosed implementations include an ultrasonic sensor stack and an acoustic resonator. The acoustic resonator may be configured to enhance ultrasonic waves transmitted by the ultrasonic sensor stack in an ultrasonic frequency range that is suitable for ultrasonic fingerprint sensors. In some examples, the acoustic resonator may include one or more low-impedance layers residing between a first higher-impedance layer and a second higher-impedance layer. Each of the one or more low-impedance layers may have a lower acoustic impedance than an acoustic impedance of the first higher-impedance layer or an acoustic impedance of the second higher-impedance layer. At least one low-impedance layer may have a thickness corresponding to a multiple of a half wavelength at a peak frequency of the acoustic resonator. The peak frequency may be within a frequency range from 1 MHz. to 20 MHz.

Abstract: Some disclosed implementations include an ultrasonic sensor stack and an acoustic resonator. The acoustic resonator may be configured to enhance ultrasonic waves transmitted by the ultrasonic sensor stack in an ultrasonic frequency range that is suitable for ultrasonic fingerprint sensors. In some examples, the acoustic resonator may include one or more low-impedance layers residing between a first higher-impedance layer and a second higher-impedance layer. Each of the one or more low-impedance layers may have a lower acoustic impedance than an acoustic impedance of the first higher-impedance layer or an acoustic impedance of the second higher-impedance layer. At least one low-impedance layer may have a thickness corresponding to a multiple of a half wavelength at a peak frequency of the acoustic resonator. The peak frequency may be within a frequency range from 1 MHz. to 20 MHz.

Abstract: Some disclosed implementations include an ultrasonic sensor stack and an acoustic resonator. The acoustic resonator may be configured to enhance ultrasonic waves transmitted by the ultrasonic sensor stack in an ultrasonic frequency range that is suitable for ultrasonic fingerprint sensors. In some examples, the acoustic resonator may include one or more low-impedance layers residing between a first higher-impedance layer and a second higher-impedance layer. Each of the one or more low-impedance layers may have a lower acoustic impedance than an acoustic impedance of the first higher-impedance layer or an acoustic impedance of the second higher-impedance layer. At least one low-impedance layer may have a thickness corresponding to a multiple of a half wavelength at a peak frequency of the acoustic resonator. The peak frequency may be within a frequency range from 1 MHz. to 20 MHz.

Abstract: Some disclosed implementations include an ultrasonic sensor stack and an acoustic resonator. The acoustic resonator may be configured to enhance ultrasonic waves transmitted by the ultrasonic sensor stack in an ultrasonic frequency range that is suitable for ultrasonic fingerprint sensors. In some examples, the acoustic resonator may include one or more low-impedance layers residing between a first higher-impedance layer and a second higher-impedance layer. Each of the one or more low-impedance layers may have a lower acoustic impedance than an acoustic impedance of the first higher-impedance layer or an acoustic impedance of the second higher-impedance layer. At least one low-impedance layer may have a thickness corresponding to a multiple of a half wavelength at a peak frequency of the acoustic resonator. The peak frequency may be within a frequency range from 1 MHz. to 20 MHz.