Self-mixing optical proximity sensors for electronic devices

Abstract

An electronic device may have optical sensors. Control circuitry may use sensor measurements in controlling adjustable components and taking other actions. The optical sensors may be self-mixing sensors such as incoherent self-mixing sensors. One or more sensors may be used in gathering sensor measurements. In configurations in which an electronic device contain multiple self-mixing sensors, multi-wavelength measurements can be gathered using incoherent light sources in the sensors that operate a set of different wavelengths. The light source of each incoherent self-mixing sensor may be a superluminescent light-emitting diode, a resonant cavity light-emitting diode, or other amplified or non-amplified spontaneous emission source. Optical systems such as lenses in a housing for an electronic device may be aligned with the self-mixing sensors. Self-mixing sensors may serve as proximity sensors, sensors for detecting touch input, sensors for measuring spectrums associated with targets of unknown materials, displacement sensors, or other sensors.