US Patent 10203662 Optical position sensor for a crown

An electronic device includes an input device having a moveable shaft, a reflective surface, an optical energy transmitter, and optical energy receivers that receive optical energy transmitted by the optical energy transmitter and reflected by the reflective surface. Movement of the moveable shaft changes the optical energy received by the optical energy receivers. The movement or position of the shaft may be determined by analyzing the optical energy received. Detectable movement may include rotation, rotation speed, rotation direction, translation, tilt, displacement, and so on. The optical energy receivers may be configured in concentric rings.