Abstract: The descried techniques may support a sensing scheme for reducing background signals in imaging sensors. A device may include a sensor configured to determine ridges and valleys of a fingerprint. The sensor may include a pixel array with each pixel of the pixel array having a set of electrodes. To reduce the background signals, the device may sense, e.g., during a transmit mode, a first set of signals associated with the pixel array using at least one electrode of the set of electrodes, and sense, e.g., during a receive mode, a second set of signals associated with the pixel array using the at least one electrode. The device may reduce a background signal associated with the sensor according to the sensing of the first set of signals and the second set of signals.

Abstract: An ultrasonic fingerprint sensor system of the present disclosure may be provided with an ultrasonic transmitter or ultrasonic transceiver having an electrode layer divided into a plurality of electrode segments. The ultrasonic fingerprint sensor system may detect an object over one or more electrode segments and provide a voltage burst to one or more selected electrode segments for localized generation of ultrasonic waves. The localized generation of ultrasonic waves may facilitate localized readout for imaging. In some implementations, the voltage burst may be provided in a single-ended drive scheme or differential drive scheme.

Abstract: A stylus-tracking device may include a piezoelectric receiver or transceiver array on a first side (e.g., underneath) a display. Image data may be acquired from the piezoelectric receiver array. The image data may correspond to signals produced by the piezoelectric receiver array in response to an acoustic signal and/or a mechanical deformation caused by a target object (e.g., a stylus) in contact with a surface, such as a cover glass, proximate a second side of the display. A doublet pattern in the image data may include a first area of having signals below a threshold level and a second area having signals above the threshold level. Based on one or more doublet pattern characteristics, a position of the target object on the surface, a force of the target object on the surface and/or a first direction of movement of the target object relative to the surface may be estimated.

Abstract: An ultrasonic fingerprint sensor system of the present disclosure may be provided with a thick electrically nonconductive acoustic layer and thin electrode layer coupled to a piezoelectric layer of an ultrasonic transmitter or transceiver. The thick electrically nonconductive acoustic layer may have a high density or high acoustic impedance value, and may be adjacent to the piezoelectric layer. The thin electrode layer may be divided into electrode segments. The ultrasonic fingerprint sensor system may use flexible or rigid substrates, and may use an ultrasonic transceiver or an ultrasonic transmitter separate from an ultrasonic receiver.

Abstract: This disclosure provides systems, methods and apparatus for a controller configured to switch operation of a fingerprint sensor among operational modes. In one aspect, a fingerprint sensor may switch from operating in a first operational mode to a second operational mode based on one or more characteristics of fingerprint image data generated with the fingerprint sensor operating in the first operational mode. One of the first operational mode or the second operational mode may be a capacitive sensing mode, and the other may be an ultrasonic sensing mode.

Abstract: An ultrasonic fingerprint sensor system of the present disclosure may be provided with a flexible substrate. The ultrasonic fingerprint sensor system may include a film stack disposed on the flexible substrate that provides acceptable acoustic coupling for fingerprint sensing. The ultrasonic fingerprint sensor system includes a high acoustic impedance layer in an acoustic path of ultrasonic waves through a display. The high acoustic impedance layer can be electrically conductive or electrically nonconductive. In some implementations, the ultrasonic fingerprint sensor system includes an ultrasonic transceiver or an ultrasonic transmitter separate from an ultrasonic receiver.

Abstract: A mobile device may include a first fingerprint sensor, including a platen, residing on a first side of the mobile device, and a display residing on a second side of the mobile device. The second side may be opposite from the first side. The mobile device may include a control system configured for communication with the first fingerprint sensor and the display. The control system may be further configured for receiving first fingerprint sensor signals from the first fingerprint sensor corresponding to a fingerprint contact area of a first finger positioned on the platen, for detecting one or more finger distortions corresponding to changes of the first fingerprint sensor signals and for controlling the mobile device based, at least in part, on the one or more finger distortions.

Abstract: An apparatus may include an ultrasonic sensor system, a platen, a set of bioimpedance electrodes proximate the platen and a control system configured for communication with the ultrasonic sensor system and the set of bioimpedance electrodes. The control system may be further configured for controlling the ultrasonic sensor system to transmit ultrasonic waves, receiving ultrasonic sensor signals from the ultrasonic sensor system corresponding to ultrasonic waves reflected from a portion of a body in contact with the platen, receiving bioimpedance measurements from the set of bioimpedance electrodes and estimating a status of one or more biometric indicators of the portion of the body based on the ultrasonic sensor signals and the bioimpedance measurements.

Abstract: An ultrasonic sensor pixel includes a substrate, a piezoelectric micromechanical ultrasonic transducer (PMUT) and a sensor pixel circuit. The PMUT includes a piezoelectric layer stack including a piezoelectric layer disposed over a cavity, the cavity being disposed between the piezoelectric layer stack and the substrate, a reference electrode disposed between the piezoelectric layer and the cavity, and one or both of a receive electrode and a transmit electrode disposed on or proximate to a first surface of the piezoelectric layer, the first surface being opposite from the cavity. The sensor pixel circuit is electrically coupled with one or more of the reference electrode, the receive electrode and the transmit electrode and the PMUT and the sensor pixel circuit are integrated with the sensor pixel circuit on the substrate.

Abstract: Some disclosed methods involve controlling an ultrasonic sensor system to transmit ultrasonic waves and receiving signals from the ultrasonic sensor system corresponding to ultrasonic waves reflected from a finger positioned on a platen. The methods may involve obtaining fingerprint image data corresponding to the signals and determining a change in a force of at least a portion of the finger on the platen corresponding to the signals.

Abstract: Disclosed are methods, devices, apparatuses, and systems for an under-display ultrasonic fingerprint sensor. A display device may include a platen, a display underlying the platen, and an ultrasonic fingerprint sensor underlying the display, where the ultrasonic fingerprint sensor is configured to transmit and receive ultrasonic waves via an acoustic path through the platen and the display. A light-blocking layer and/or an electrical shielding layer may be provided between the ultrasonic fingerprint sensor and the display, where the light-blocking layer and/or the electrical shielding layer are in the acoustic path. A mechanical stress isolation layer may be provided between the ultrasonic fingerprint sensor and the display, where the mechanical stress isolation layer is in the acoustic path.

Abstract: An array of piezoelectric ultrasonic transducer elements includes a plurality of superpixel regions. Each superpixel region includes at least two pixel sets, a first pixel set of the at least two pixel sets being disposed in a central portion of the superpixel region, and at least a second pixel set being disposed in an outer portion of the superpixel region. An electrical coupling may be provided between the array and transceiver electronics. The transceiver electronics may be configured to operate the array in a selectable one of a first mode and a second mode. In the first mode, the array generates a substantially plane ultrasonic wave having a first acoustic pressure. In the second mode, the array generates, from each superpixel region, a focused beam having a second acoustic pressure that is substantially higher than the first acoustic pressure.

Abstract: This disclosure provides systems, methods and apparatus for a controller configured to switch operation of a fingerprint sensor among operational modes. In one aspect, a fingerprint sensor may switch from operating in a first operational mode to a second operational mode based on one or more characteristics of fingerprint image data generated with the fingerprint sensor operating in the first operational mode. One of the first operational mode or the second operational mode may be a capacitive sensing mode, and the other may be an ultrasonic sensing mode.

Abstract: This disclosure provides systems, methods and apparatus for a controller configured to switch operation of a fingerprint sensor among operational modes. In one aspect, a fingerprint sensor may switch from operating in a first operational mode to a second operational mode based on one or more characteristics of fingerprint image data generated with the fingerprint sensor operating in the first operational mode. One of the first operational mode or the second operational mode may be a capacitive sensing mode, and the other may be an ultrasonic sensing mode.

Abstract: An apparatus may include an ultrasonic sensor system, a platen, a set of bioimpedance electrodes proximate the platen and a control system configured for communication with the ultrasonic sensor system and the set of bioimpedance electrodes. The control system may be further configured for controlling the ultrasonic sensor system to transmit ultrasonic waves, receiving ultrasonic sensor signals from the ultrasonic sensor system corresponding to ultrasonic waves reflected from a portion of a body in contact with the platen, receiving bioimpedance measurements from the set of bioimpedance electrodes and estimating a status of one or more biometric indicators of the portion of the body based on the ultrasonic sensor signals and the bioimpedance measurements.

Abstract: Some disclosed methods involve controlling an ultrasonic sensor system to transmit ultrasonic waves and receiving signals from the ultrasonic sensor system corresponding to ultrasonic waves reflected from a finger positioned on a platen. The methods may involve obtaining fingerprint image data corresponding to the signals and determining a change in a force of at least a portion of the finger on the platen corresponding to the signals.

Abstract: A mobile device may include a first fingerprint sensor, including a platen, residing on a first side of the mobile device, and a display residing on a second side of the mobile device. The second side may be opposite from the first side. The mobile device may include a control system configured for communication with the first fingerprint sensor and the display. The control system may be further configured for receiving first fingerprint sensor signals from the first fingerprint sensor corresponding to a fingerprint contact area of a first finger positioned on the platen, for detecting one or more finger distortions corresponding to changes of the first fingerprint sensor signals and for controlling the mobile device based, at least in part, on the one or more finger distortions.

Abstract: Methods, systems and storage media are described, each of which may be used to generate an image of an object using ultrasonic plane waves. For example, the generated image may be of a target object positioned on a platen surface. The image may be derived from corrected output signals obtained from a plurality of selected sensor pixels. The corrected output signals may adjust for diffraction of reflected ultrasonic plane waves from a target object positioned on the platen surface. The target object may be a finger or a tip of a stylus.

Abstract: This disclosure provides systems, methods and apparatus for a controller configured to switch operation of a fingerprint sensor among operational modes. In one aspect, a fingerprint sensor may switch from operating in a first operational mode to a second operational mode based on one or more characteristics of fingerprint image data generated with the fingerprint sensor operating in the first operational mode. One of the first operational mode or the second operational mode may be a capacitive sensing mode, and the other may be an ultrasonic sensing mode.

Abstract: A piezoelectric micromechanical ultrasonic transducer (PMUT) includes a diaphragm disposed over a cavity, the diaphragm including a piezoelectric layer stack including a piezoelectric layer, a first electrode electrically coupled with transceiver circuitry, and a second electrode electrically coupled with the transceiver circuitry. The first electrode may be disposed in a first portion of the diaphragm, and the second electrode may be disposed in a second, separate, portion of the diaphragm. Each of the first and the second electrode is disposed on or proximate to a first surface of the piezoelectric layer, the first surface being opposite from the cavity. The PMUT is configured to transmit first ultrasonic signals by way of the first electrode during a first time period and to receive second ultrasonic signals by way of the second electrode during a second time period, the first time period and the second time period being at least partially overlapping.