Patent ID: 6995356

Claim:
An optical encoder device, comprising: an optical emitter emitting light, the optical emitter having a light emission direction; an optical detector detecting light emitted by the optical emitter, the optical detector having a light detection direction different from the light emission direction; an optical element controlling an optical path between the optical emitter and the optical detector such that light emitted by the optical emitter is detected by the optical detector, the optical element comprising a first surface and a second surface facing each other, the first and second surfaces reflecting light emitted by the optical emitter and controlling the optical path between the optical emitter and the optical detector; and a free area arranged between the first and second surfaces accommodating a moveable optical encoding unit, the moveable optical encoding unit receiving collimated light and comprising a plurality of alternating transparent and opaque encoding elements wherein the plurality of alternating transparent and opaque encoding elements of the optical encoding unit affects the optical path.