Patent ID: 6222183
Filing Date: 2001-04-24
Classification: G01D

Abstract:
An optical encoder, comprising:a mobile code plate to convert input light into encoded output light;a light source unit to scan one or more arcuate strip-shaped regions on said mobile code plate with said input light during movement of said mobile code plate; anda photodetector unit to detect said output light that has been encoded by said mobile code plate,wherein at least two of said arcuate strip-shaped regions are scanned by said input light to generate at least two types of output light having mutually different optical paths, in order to perform said encoding, andin at least one of said at least two arcuate strip-shaped regions an optical path alteration means is provided such as to generate output light having an optical path that does not lie in an axial direction of an optic axis of said input light nor in a rotational direction of movement of said mobile code plate.