Abstract: An electronic device may have a sensor to measure ambient flicker. The sensor may be a sigma-delta converter. The flicker may be calculated based on the voltage output of the sigma-delta converter and the number of times the sigma-delta converter is triggered during a predetermined period, thereby reducing the voltage output. In particular, a fast Fourier transform (FFT) may be used on these values to determine the flicker. If desired, filtering and/or non-uniform sampling may be incorporated to avoid aliasing. Additionally or alternatively, a Lomb-Scargle spectral analysis may be used to prevent the attenuation of the measured flicker signals. As an alternative to using a sigma-delta converter to determine ambient flicker, a folding capacitive transimpedance amplifier (C-TIA) circuit or a circuit with an analog to digital converter and digital filter may be used to measure the ambient flicker.

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: 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: Systems and methods for detection of incident light are described. An optical imaging sensor is positioned at least partially within an active display area of a display and is configured to detect and characterize one or more properties of light incident to the active display area of the display.

Abstract: An electronic device may have a display with an array of pixels configured to display images for a user. The electronic device may have an ambient light sensor for gathering ambient light information. The ambient light sensor may be at least partially covered by the display. The ambient light sensor may be switched into use during blanking periods when a portion of the display overlapping with the display is temporarily turned off. The ambient light sensor may include a photodetector, a first stage with an amplifier, first and second capacitors selectively coupled across the amplifier, and a second accumulation stage. During blanking time, the first capacitor may integrate photodetector current. During non-blanking, the charge stored in the first capacitor may be transferred to the second accumulation stage while the second capacitor applies an offset voltage to the photodetector to prevent undesired charge injection into the photodetector.

Abstract: An electronic device may have a display with an array of pixels configured to display images for a user. The electronic device may have an ambient light sensor for gathering ambient light information. The ambient light sensor may be at least partially covered by the display. The ambient light sensor may be switched into use during blanking periods when a portion of the display overlapping with the display is temporarily turned off. The ambient light sensor may include a photodetector, a first stage with an amplifier, first and second capacitors selectively coupled across the amplifier, and a second accumulation stage. During blanking time, the first capacitor may integrate photodetector current. During non-blanking, the charge stored in the first capacitor may be transferred to the second accumulation stage while the second capacitor applies an offset voltage to the photodetector to prevent undesired charge injection into the photodetector.

Abstract: Systems and methods for detection of incident light are described. An optical imaging sensor is positioned at least partially within an active display area of a display and is configured to detect and characterize one or more properties of light incident to the active display area of the display.

Abstract: Systems and methods for detection of incident light are described. An optical imaging sensor is positioned at least partially within an active display area of a display and is configured to detect and characterize one or more properties of light incident to the active display area of the display.

Abstract: Systems and methods for detection of incident light are described. An optical imaging sensor is positioned at least partially within an active display area of a display and is configured to detect and characterize one or more properties of light incident to the active display area of the display.

Abstract: Semiconductor devices are described that are configured to have a state of operation defined by a connection between at least one inner bump assembly and a selected outer bump assembly. In an implementation, the semiconductor device, which may be a wafer-level (chip-scale) package semiconductor device, includes an integrated circuit chip, a plurality of outer bump assemblies disposed on the chip, and one or more inner bump assemblies disposed on the chip so that the inner bump assemblies are at least partially surrounded by the outer bump assemblies. At least one of the inner bump assemblies is configured to be connected to a selected outer bump assembly to cause the integrated circuit chip to have a desired state of operation.