Abstract: A battery pack, comprising a first cell and a second cell connected in series, the first cell having a current cut-off device and having a first failure voltage, the current cut-off device being configured to be able to break a circuit in response to a voltage value of the first cell reaching or exceeding the first failure voltage, and the second cell having no current cut-off device. The battery pack may use a soft pack battery as the second cell, having advantages such as high energy density, low impedance, high discharge power, a low rate of temperature rise during high-rate discharge, and flexibility in dimensions.

Abstract: According to examples, a system may use gaze direction information to perform tone mapping or chromatic adaptation for virtual reality (VR) environments. The system may include a processor and a memory storing instructions. When the processor executes the instructions, the system may determine a user focus location within a physical environment. An image corresponding to the physical environment may be received. The system may determine a visual property of the physical environment corresponding to the user focus location. The system may modify a color mapping of a region of the image based on the determined visual property to generate an output image.

Abstract: A display assembly with dielectric filters is presented herein. The display assembly includes a light source assembly, a dielectric filter array, and a modulation layer. The light source assembly generates laser light in multiple color channels, and each color channel is associated with a different laser emission spectrum. The dielectric filter array includes respective sets of reflective dielectric filters for each color channel. Each set of reflective dielectric filters is matched to the different laser emission spectrum such that reflective dielectric filters in each set transmit light in the different laser emission spectrum and reflect light outside of the different laser emission spectrum. The modulation layer is positioned between a first electrode layer patterned on the dielectric filter array and a second electrode layer. The modulation layer modulates light from the dielectric filter array based on emission instructions applied via the first and second electrode layers to form an image.

Abstract: One example method for adaptive mixed reality includes estimating ambient lighting conditions using one or more sensors; calibrating each of the one or more sensors spatially or spectrally; determining a color point based on the ambient lighting conditions; and modifying a mixed reality display based on the color point, wherein the mixed reality display comprises virtual reality (VR) content and pass-through (PT) content.

Abstract: Embodiments of the present disclosure relate to a display assembly with color calibration for improving accuracy of displayed colors under thermal shifts. A data processing circuit of the display assembly determines color compensation coefficients corresponding to an operating temperature of a display panel, each color compensation coefficient accounting for a thermal shift of a respective color component at the operating temperature. The data processing circuit applies the color compensation coefficients to color transform elements corresponding to an initial temperature to determine a corrected version of the color transform elements corresponding to the operating temperature.

Abstract: A lens assembly includes an optical element having an outward-facing surface with a cornea-shaped contour. The lens assembly includes a housing that carries an optical element. The housing at least partially houses an image sensor. The image sensor is positioned to receive image light from the optical element. The lens assembly is an artificial eye system that may be used to mimic a human eye while operating or testing a head-mounted display.

Abstract: Systems and methods for an ambient light sensor (ALS) disposed under a display layer. In some implementations, an ALS reading is adjusted by compensating for light leakage in a display environment. In some aspects, a display leakage component may be determined based on image content driven onto a display pixel array during the ALS reading. An ambient light measurement may be generated by subtracting the display leakage component from the ALS reading and then adjusting a display brightness of the display pixel array in response to the ambient light measurement.

Abstract: One embodiment includes a sequential spectral imaging system with a color filter disposed over imaging sensor. The color filter includes zones of multiple color elements of discrete or continuous spectra. The color filter is configured to have multiple cycles of wavelength bands along diagonal lines of the imaging sensor, each cycle of wavelength bands includes a full spectra from red to blue. Another embodiment combines an imaging sensor of a wide FOV with pixelated color filters and a spectra sensor of smaller FOV. A calibration technique acquires imaging sensor's spectral response. The sequential spectral imaging system acquires a sequence of continuous frames of spatial and spectral data during recording an object moving relatively to the camera. Multiple frames of the moving object are tracked sequentially. Image processing to correct distortion and extract features enables identification and tracking of the object. The object's full spectra is established by connecting different frames.

Abstract: An electronic device may be provided with one or more light-sensing components such as a camera and a color ambient light sensor. Optical structures such as camera lenses or a light pipe may be used to convey light from a window in an electronic device to a light-sensing component. One or more infrared-light-blocking-and-visible-light transmitting light filters may be interposed between a light-receiving window in an electronic device and a light-sensing component. The light filters may include infrared-light-blocking glass substrates, silver or other infrared-light-blocking thin films, and/or thin-film interference filters formed from stacks of dielectric layers that serve as infrared light-blocking layers.

Abstract: An electronic device may have a housing in which a display is mounted. The display may have an active area in which images are displayed by an array of pixels and an inactive area that is free of pixels. A color ambient light sensor may make color and luminance measurements on ambient light received through an ambient light sensor window in the inactive area of the display or elsewhere in the electronic device. The color ambient light sensor may have color ambient light sensor elements of different colors. The ambient light sensor elements may extend in a row along an edge of the display or may have other configurations. Analog-to-digital converter circuitry and switching circuitry may gather color ambient light sensor measurements and measurements indicative of whether or not the color ambient light sensor has been obscured by an external object from the light sensor elements.

Abstract: An electronic device may have a display with a transparent layer such as a cover layer. An ambient light sensor may be aligned with an ambient light sensor window formed from an opening in a masking layer on the transparent layer in an inactive portion of the display. To help mask the ambient light sensor window from view, the ambient light sensor window may be provided with a black coating that matches the appearance of surrounding masking layer material while allowing light to reach the ambient light sensor. The black coating may include multiple pigments and may have a flat spectrum to enhance color ambient light measurements made with the ambient light sensor. The black coating may include a polymer binder or other binder that contains multiple pigments. The pigments may include a black pigment, a blue pigment, and an infrared-light-transparent pigment and/or other pigments.

Abstract: In an RF power calculation apparatus and method for an MRI system, a first power calculation processor calculates a first power of an RF signal received by a first receiving method, a second power calculation processor calculates a second power of the RF signal received by a second receiving method, a difference calculation processor calculates the difference between the first power and second power, an RF power calculation processor calculates an RF power of the RF signal on the basis of the first power and second power when the difference is smaller than a first threshold.

Abstract: A control computer for a magnetic resonance imaging system has an analog-to-digital conversion array, a multiplexer array connected to the analog-to-digital conversion array, and a control module that receives at least one input signal via the multiplexer array and the analog-to-digital conversion array. A signal processing board for a magnetic resonance imaging system has a substrate with the aforementioned components thereon that form the aforementioned control computer.

Abstract: A near-eye display (NED) comprises an electronic display, an optical assembly, a scanning assembly, and a controller. The controller generates display instructions based in part on content. The display instructions describe a resolution within an adjustable range of resolutions and a frame rate within adjustable range of frame rates. The electronic display emits a plurality of light rays at the frame rate based on the display instructions. The scanning assembly shifts a direction of at least one of the plurality of light rays in accordance with the display instructions. The optical assembly controls a field of view at an eye box and directs the plurality of light rays including the at least one shifted light ray toward the eye box. The plurality of light rays form a virtual display that displays the content at the resolution and the frame rate.

Abstract: A Fresnel optical element includes a Fresnel surface formed in a material. The Fresnel surface includes a plurality of Fresnel feature that include an active surface and a draft surface. A light absorptive layer is selectively disposed over the draft surface of the Fresnel features. The light absorptive surface is configured to absorb a majority of visible light encountering the light absorptive layer.

Abstract: An electronic device may be provided with a color sensing ambient light sensor. The color sensing ambient light sensor may measure the color of ambient light. Control circuitry in the electronic device may use information from the color sensing ambient light sensor in adjusting a display in the electronic device or taking other action. The color sensing ambient light sensor may have light detectors with different spectral responses. A test system may be used to calibrate the color sensing light sensor. The test system may have a tunable light source with light-emitting diodes that are turned on in sequence while gathering measured responses from the detectors. Numerical optimization techniques may be used to produce final versions of the spectral responses for the light detectors from the measured responses and corresponding calibration data that is stored in the electronic device.

Abstract: An electronic device may have a display with a cover layer. An ambient light sensor may be aligned with an ambient light sensor window formed from an opening in a masking layer on the cover layer in an inactive portion of the display. To help mask the ambient light sensor window from view, the ambient light sensor window may be provided with a black coating that matches the appearance of surrounding masking layer material while allowing light to reach the ambient light sensor. The black coating may be formed from a black physical vapor deposition thin-film inorganic layer with a high index of refraction. An antireflection layer formed from a stack of dielectric layers may be interposed between the black thin-film inorganic layer and the display cover layer.

Abstract: An electronic device may be provided with a display mounted in a housing. A color sensing ambient light sensor may measure the color of ambient light. The color sensing ambient light sensor may be mounted in alignment with an ambient light sensor window formed in an inactive area of the display. The color sensing ambient light sensor may be formed from detectors on a semiconductor substrate. The detectors may include detectors that have spectral sensitivity profiles matching those of color matching functions. The color sensing ambient light sensor may include an infrared light detector. Light redirecting structures such as a diffuser, prism film, negative lens film, or privacy film may be used in directing light into the ambient light sensor. The color sensing ambient light sensor may be calibrated by exposing the sensor to light sources of different types.

Abstract: A near-eye display (NED) comprises an electronic display, an optical assembly, a scanning assembly, and a controller. The controller generates display instructions based in part on content. The display instructions describe a resolution within an adjustable range of resolutions and a frame rate within adjustable range of frame rates. The electronic display emits a plurality of light rays at the frame rate based on the display instructions. The scanning assembly shifts a direction of at least one of the plurality of light rays in accordance with the display instructions. The optical assembly controls a field of view at an eye box and directs the plurality of light rays including the at least one shifted light ray toward the eye box. The plurality of light rays form a virtual display that displays the content at the resolution and the frame rate.

Abstract: An electronic device may be provided with a display mounted in a housing. An ambient light sensor may measure the color of ambient light through an ambient light sensor window in the display. The ambient light sensor may have an array of light detectors on a semiconductor die. The light detectors may include color matching function light detectors that have spectral sensitivity profiles that match standard observer color matching functions and may include spectral sensing light detectors. The spectral sensing light detectors may have narrower full width at half maximum bandwidths than the color matching function light detectors and may be used with the color matching function light detectors to measure an ambient light spectrum. The color matching function light detectors may be used to measure the color of ambient light.