Patent ID: 7449675
Filing Date: 2008-11-11
Classification: G01D

Abstract:
1. An optical encoder comprising: a coding element having a track with transparent and opaque sections that have the same width dimension; a light emitting diode (LED) positioned to output light to the track; and a photodetector array, positioned to detect light that passes through the transparent sections of the track, having multiple photodetectors with the same width dimension, wherein the width dimension of each one of the photodetectors is larger than the width dimension of each one of the transparent sections of the track and larger than the width dimension of each one of the opaque sections of the track; wherein the width dimension of the transparent sections of the track and the width dimension of the photodetectors are mismatched by a ratio of 3:2 such that the width dimension of three transparent sections equals the width dimension of two photodetectors.