Patent ID: 7714272
Filing Date: 2010-05-11
Classification: G01D

Abstract:
1. An optical absolute rotary encoder, comprising: an optical scale having an absolute pattern representing a code corresponding to a single absolute value including a combination of a transmitting area and an intercepting area, the optical scale having a first side and an opposing second side; a light emitting unit located adjacent the first side of the optical scale and configured to project light on the optical scale; a light receiving unit located at the same first side as the light emitting unit with respect to the optical scale, and configured to receive light passing through the transmitting area of the optical scale, wherein the light projected from the light emitting unit passes through the optical scale only once per emission; and a light guide unit configured to guide the light projected from the light emitting unit and passing through the transmitting area to the light receiving unit, wherein the optical scale and the light emitting unit are configured to rotate relative to each other about an axis of rotation, and the light receiving unit is disposed on the axis of rotation, wherein