Abstract:
An electronic device can include housing with first and second housing portions configured to rotate relative to one another about a hinge, a hinge angle encoder that rotates with the hinge, an emitter that emits light towards the hinge angle encoder, and a sensor die that receives light reflecting back from the hinge angle encoder. The hinge angle encoder may include an absorptive polarizing filter layer and a reflective diffuser layer. A pixelated polarizer may be formed overlapping an array of photodetectors in the sensor die. The electronic device may include processing circuitry configured to compute a hinge angle by which the first and second housing portions are rotated based on one or more intensity values acquired using the array of photodetectors.
Abstract:
In some embodiments, a device includes a light-emitting display, and an optical emitter positioned behind the light-emitting display. The optical emitter is configured to emit light through the light-emitting display. A processor is configured to synchronize a first illumination timing of the optical emitter and a second illumination timing of the light-emitting display. In some embodiments, a device includes an optical transceiver processor and a display processor. The display processor is configured to output timing information to a light-emitting display and to the optical transceiver processor, and the optical transceiver processor is configured to cause an optical transceiver to emit or receive light in synchronization with the timing information output by the display processor.
Abstract:
In some embodiments, a device includes a light-emitting display, and an optical emitter positioned behind the light-emitting display. The optical emitter is configured to emit light through the light-emitting display. A processor is configured to synchronize a first illumination timing of the optical emitter and a second illumination timing of the light-emitting display. In some embodiments, a device includes an optical transceiver processor and a display processor. The display processor is configured to output timing information to a light-emitting display and to the optical transceiver processor, and the optical transceiver processor is configured to cause an optical transceiver to emit or receive light in synchronization with the timing information output by the display processor.
Abstract:
An electronic device may have a display with an array of pixels that display images for a user. The electronic device may have an ambient light sensor for gathering ambient light information. A subset of the pixels in the array of pixels may overlap the ambient light sensor so that ambient light passing through the subset of pixels may be measured. Each pixel may have an emission enable transistor coupled in series with a light-emitting diode. Control circuitry in the electronic device may disable the subset of pixels to reduce stray light during ambient light measurements while enabling remaining pixels in the array of pixels to display an image. Ambient light sensor circuitry may gather ambient light sensor measurements over one or more periods by using transfer transistors to transfer change from the photodetectors to charge storage capacitors formed from floating diffusions in a common substrate.
Abstract:
An electronic device may have a display with a brightness that is adjusted based on ambient light data from one or more ambient light sensors. An ambient light sensor may include at least one silicon-based photosensor. The silicon-based photosensor may generate a corresponding raw sensor reading. Processing circuitry associated with the ambient light sensor may analyze the raw sensor reading to determine the type of light source that is present by comparing measurements from at least two different photosensors, by determining the color temperature of the light source, and/or by determining the modulation frequency of the light source. A compensation factor may then be selected by referring to a lookup table. The processing circuitry may compute a compensated sensor reading based on the raw sensor reading and the selected compensation factor. The brightness of the display may be adjusted based on the compensated sensor reading computed in this way.
Abstract:
An electronic device may have a display with a brightness that is adjusted based on data gathered from one or more ambient light sensors (ALSs). In one suitable arrangement, an ALS may include a photodiode, a temperature sensor, a scaler, an analog-to-digital converter (ADC), and a subtractor. The subtractor may have a first input coupled to the photodiode via the ADC, a second input coupled to the temperature sensor via the scaler, and an output on which a leakage-compensated sensor output is provided. In another suitable arrangement, the ALS may include first and second photodiodes, a light blocking layer formed over the second photodiode, a scaler, and a subtractor. The subtractor may have a first input coupled to the first photodiode, a second input coupled to the second photodiode via the scaler, and an output on which a leakage-compensated sensor output is provided.
Abstract:
An electronic device may be provided that has a display. The display may produce stray light when producing images for a user. The electronic device may have an ambient light sensor for measuring ambient light levels. Ambient light data may be used in adjusting display brightness. The display may be periodically disabled to prevent the stray light from interfering with the ambient light sensor. An integrating analog-to-digital converter may be used in gathering sensor data from the ambient light sensor. Control circuitry may be configured to remove background signals from ambient light sensor data. The background signals may be associated with leakage current that arises due to offset voltages in an operational amplifier in the integrating analog-to-digital converter. The operational amplifier may have an analog autozeroing capability or control circuitry may be used to subtract background data from ambient light sensor data.
Abstract:
An electronic device may have an ambient light sensor for gathering ambient light measurements. The ambient light sensor may include multiple channels for measuring different wavelengths of ambient light. An additional, modified, channel may be formed in the ambient light sensor to measure radio-frequency signals that may interfere with the ambient light measurements due to electromagnetic interference. Alternatively, circuitry separate from the ambient light sensor, such as an antenna, may measure the radio-frequency signals. If the radio-frequency signals exceed a threshold, the ambient light sensor measurements taken in the presence of the radio-frequency signals may be discarded or corrected. If the radio-frequency signals do not exceed a threshold, the ambient light sensor measurements may be kept. Therefore, the ambient light measurements that are kept and relied upon by the electronic device may be free from electromagnetic interference.
Abstract:
A method of operating a laser includes generating a first signal having a first frequency, and generating a second signal having a second frequency. The first frequency varies in accord with an amplitude of a drive current provided to a laser. The method further includes incrementing or decrementing a count responsive to a relationship between the first frequency and the second frequency; determining the count satisfies a threshold count; and modifying operation of the laser when the count satisfies the threshold count.
Abstract:
An electronic device may have a display with an array of pixels that display images for a user. The electronic device may have an ambient light sensor for gathering ambient light information. A subset of the pixels in the array of pixels may overlap the ambient light sensor so that ambient light passing through the subset of pixels may be measured. Each pixel may have an emission enable transistor coupled in series with a light-emitting diode. Control circuitry in the electronic device may disable the subset of pixels to reduce stray light during ambient light measurements while enabling remaining pixels in the array of pixels to display an image. Ambient light sensor circuitry may gather ambient light sensor measurements over one or more periods by using transfer transistors to transfer change from the photodetectors to charge storage capacitors formed from floating diffusions in a common substrate.