Abstract: Various implementations disclosed herein include devices, systems, and methods that perform gaze tracking using combinations of ultrasound and imaging data. Some implementations detect a first attribute of an eye using imaging measurements in a first image of the eye, and a first location associated with the first attribute is determined in a 3D coordinate system based on depth information. A second attribute of the eye is detected based on depth information from ultrasound based measurements of the eye, and a second location associated with the second attribute is determined in the 3D coordinate system based on the depth information and a 3D model of a portion of the eye. A gaze direction in the 3D coordinate system is determined based on the first location and the second location. In some implementations, user characteristics are identified (e.g., authentication) using ultrasonic biometric characteristics with imaging biometrics.

Abstract: A pair of eyeglasses may include one or more adjustable lenses that are each configured to align with a respective one of a user's eyes. The adjustable lenses may each include electrically modulated optical material such as one or more liquid crystal cells. The liquid crystal cells may include arrays of electrodes that extend along one, two, three, four, or more than four directions. Control circuitry may apply control signals to the array of electrodes in each liquid crystal cell to produce a desired phase profile. Each lens may be foveated such that portions of the lens within the user's gaze exhibit a different phase profile than portions of the lens outside of the user's gaze. The control circuitry may adjust the location of the optically distinct area so that it remains aligned with the user's gaze.

Abstract: Various implementations disclosed herein include devices, systems, and methods that perform gaze tracking using combinations of ultrasound and imaging data. Some implementations detect a first attribute of an eye using imaging measurements in a first image of the eye, and a first location associated with the first attribute is determined in a 3D coordinate system based on depth information. A second attribute of the eye is detected based on depth information from ultrasound based measurements of the eye, and a second location associated with the second attribute is determined in the 3D coordinate system based on the depth information and a 3D model of a portion of the eye. A gaze direction in the 3D coordinate system is determined based on the first location and the second location. In some implementations. user characteristics are identified (e.g., authentication) using ultrasonic biometric characteristics with imaging biometrics.

Abstract: A head-mounted device may have a display that displays content for a user. Head-mounted support structures in the device support the display on the head of the user. A lens module in the head-mounted device may include a transparent lens element, a positioner that extends around the periphery of the transparent lens element, and an actuator that selectively shifts the positioner in a first direction. Shifting the positioner in the first direction causes the transparent lens element to be biased in a second direction that is orthogonal to the first direction at multiple points around the periphery of the transparent lens elements. The positioner may be attached to guide structures that each have a respective angled slot. Each angled slot may receive a respective tab of the transparent lens element or a respective tab of a lens shaping element that is attached to the transparent lens element.

Abstract: Ultrasonic transducers may be used to track the position of an object. For example, eyewear such as a pair of glasses or other head-mounted device may use ultrasonic transducers to track a user's eye position and gaze direction. To increase positioning accuracy over short-range distances, an array of ultrasonic transducers with different center frequencies may be formed on a common substrate. The closely spaced ultrasonic transducers with relatively small individual bandwidths may be used to simulate a single transducer with a larger bandwidth. Control circuitry may adjust the phases of the transducers in the array to steer the ultrasonic signal beam towards the user's eye and/or to receive an ultrasonic signal beam from the direction of the user's eye. The control circuitry may use time delay and/or phase delay measurement techniques to determine a distance and/or direction to the user's eye using the ultrasonic transducer arrays.

Abstract: A lens system may include overlapping lenses that shift laterally with respect to each other to provide vision correction. The lens system may include first and second lenses that include one or more freeform surfaces and one or more non-freeform surfaces. One or more of these lens surfaces may provide adjustable presbyopic vision correction and/or a static distance vision correction.

Abstract: A pair of eyeglasses may include one or more adjustable lenses that are each configured to align with a respective one of a user's eyes. The adjustable lenses may each include electrically modulated optical material such as one or more liquid crystal cells, each having a phase profile that is adjusted using patterned electrodes. Analog voltages may be provided to the patterned electrodes through variable-resistance conductive paths that are each coupled to a subset of the patterned electrodes. Digital voltage selection circuitry may be used to select which analog voltage to apply to each of the variable-resistance conductive paths from a predetermined set of analog voltages that are generated off of the lens. The digital voltage selection circuitry may include an array of multiplexers, each of which selects a desired voltage based on control signals received from digital control circuitry such a shift register and/or a decoder.

Abstract: An electronic device may include one or more ultrasonic temperature sensors. The ultrasonic temperature sensors may be formed in openings or cavities in a housing of the electronic device. The ultrasonic temperature sensors may include ultrasonic transmitters that transmit signals at different ultrasonic frequencies and ultrasonic receivers that receive the transmitted signals. Phase differences between the received ultrasonic signals may be used to determine the speed of sound of ambient air and therefore calculate the temperature of the ambient air. The ultrasonic transmitters and receivers may include piezoelectric micromachined ultrasound transducers (PMUTs). Each transmitter and receiver may be a dedicated transmitter or receiver, or may transmit and receive ultrasonic signals. Each receiver may include an array of PMUTs that receive ultrasonic signals of different frequencies. The PMUTS may be formed on complementary metal-oxide semiconductors (CMOS).

Abstract: A pair of eyeglasses may include one or more adjustable lenses. An adjustable lens may include electrically modulated optical material such as one or more liquid crystal cells having a phase profile that is adjusted using patterned electrodes. Digital-to-analog converter circuits may provide voltages to the electrodes. To save space on the lens, a smaller number of digital-to-analog converter circuits may provide voltages to a greater number of electrodes by sequentially coupling and decoupling the digital-to-analog converter circuits to different groups of electrodes, advancing from group-to-group with each clock cycle by a number of electrodes that is less than the number of digital-to-analog converter circuits. At least one of the electrodes in each group may be driven at the same voltage for two consecutive clock cycles to avoid erroneous voltages resulting from the parasitic capacitance between adjacent fingers.

Abstract: An electronic device may have back-to-back displays. A user-facing display may have microlenses, tunable lens structures, holograms, lasers, and other structures for displaying images in multiple eye boxes while the electronic device is being worn on the head of a user. In some configurations, a switchable diffuser may be incorporated into the user-facing display. In one mode, the switchable diffuser allows microlenses of the pixels of the user-facing display to provide images to eye boxes in which images from the display are viewable. In another mode, the switchable diffuser diffuses light from the pixels so that the user-facing display may be used while the device is being held in the hand of the user.

Abstract: Image-sensing devices include odd-symmetry gratings that cast interference patterns over a photodetector array. Grating features offer considerable insensitivity to the wavelength of incident light, and to the manufactured distance between the grating and the photodetector array. Photographs and other image information can be extracted from interference patterns captured by the photodetector array. Images can be captured without a lens, and cameras can be made smaller than those that are reliant on lenses and ray-optical focusing.

Abstract: A pair of eyeglasses may include one or more adjustable lenses that are each configured to align with a respective one of a user's eyes. The adjustable lenses may each include electrically modulated optical material such as one or more liquid crystal cells. The liquid crystal cells may include arrays of electrodes that extend along one, two, three, four, or more than four directions. Control circuitry may apply control signals to the array of electrodes in each liquid crystal cell to produce a desired phase profile. Each lens may be foveated such that portions of the lens within the user's gaze exhibit a different phase profile than portions of the lens outside of the user's gaze. The control circuitry may adjust the location of the optically distinct area so that it remains aligned with the user's gaze.

Abstract: A pair of eyeglasses may include one or more adjustable lenses that are each configured to align with a respective one of a user's eyes. The adjustable lenses may include a foveated liquid crystal adjustable lens stacked with a non-liquid-crystal adjustable lens such as a fluid-filled lens or an Alvarez lens. The foveated adjustable lens may include electrically modulated optical material such as one or more liquid crystal cells. The liquid crystal cells may include arrays of electrodes that extend along one, two, three, four, or more than four directions. Control circuitry may apply control signals to the array of electrodes in each liquid crystal cell to produce a desired phase profile. Each lens may be foveated such that portions of the lens within the user's gaze exhibit a different phase profile than portions of the lens outside of the user's gaze.

Abstract: Image-sensing devices include odd-symmetry gratings that cast interference patterns over a photodetector array. Grating features offer considerable insensitivity to the wavelength of incident light, and to the manufactured distance between the grating and the photodetector array. Photographs and other image information can be extracted from interference patterns captured by the photodetector array. Images can be captured without a lens, and cameras can be made smaller than those that are reliant on lenses and ray-optical focusing.

Abstract: A pair of eyeglasses may include one or more adjustable lenses that are each configured to align with a respective one of a user's eyes. The adjustable lenses may each include electrically modulated optical material such as one or more liquid crystal cells. The liquid crystal cells may include arrays of electrodes that extend along one, two, three, four, or more than four directions. Control circuitry may apply control signals to the array of electrodes in each liquid crystal cell to produce a desired phase profile. Each lens may be foveated such that portions of the lens within the user's gaze exhibit a different phase profile than portions of the lens outside of the user's gaze. The control circuitry may adjust the location of the optically distinct area so that it remains aligned with the user's gaze.

Abstract: An imaging system includes a phase grating overlying a two-dimensional array of pixels, which may be thermally sensitive pixels for use in infrared imaging. The phase grating comprises a two-dimensional array of identical subgratings that define a system of Cartesian coordinates. The subgrating and pixel arrays are sized and oriented such that the pixels are evenly distributed with respect to the row and column intersections of the subgratings. The location of each pixel thus maps to a unique location beneath a virtual archetypical subgrating. Portions of the phase grating extend beyond the edges of the pixels array to interference pattern in support of Fourier-domain imaging.

Abstract: Image-sensing devices include odd-symmetry gratings that cast interference patterns over a photodetector array. Grating features offer considerable insensitivity to the wavelength of incident light, and also to the manufactured distance between the grating and the photodetector array. Photographs and other image information can be extracted from interference patterns captured by the photodetector array. Images can be captured without a lens, and cameras can be made smaller than those that are reliant on lenses and ray-optical focusing.

Abstract: An array of diffraction-pattern generators employ phase anti-symmetric gratings to projects near-field spatial modulations onto a closely spaced array of photoelements. Each generator in the array of generators produces point-spread functions with spatial frequencies and orientations of interest. The generators are arranged in an irregular mosaic with little or no short-range repetition. Diverse generators are shaped and placed with some irregularity to reduce or eliminate spatially periodic replication of ambiguities to facilitate imaging of nearby scenes.

Abstract: An optical method of measuring motion employs a phase grating that produces a diffraction pattern responsive to light from an imaged scene. First and second images of the diffraction pattern are captured and compared to produce an image comparison. Apparent motion is then calculated from the image comparison.

Abstract: A sensing device with an odd-symmetry grating projects near-field spatial modulations onto an array of closely spaced pixels. Due to physical properties of the grating, the spatial modulations are in focus for a range of wavelengths and spacings. The spatial modulations are captured by the array, and photographs and other image information can be extracted from the resultant data. Pixels responsive to infrared light can be used to make thermal imaging devices and other types of thermal sensors. Some sensors are well adapted for tracking eye movements, and others for imaging barcodes and like binary images. In the latter case, the known binary property of the expected images can be used to simplify the process of extracting image data.