Patent ID: 7638756

Claim:
An optical encoder comprising: a coding element having a track with an alternating pattern of transparent and opaque sections that have the same width dimension, wherein the width dimension of the transparent and opaque sections determines a resolution of the coding element; 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, the photodetector array having a cycle of four photodetectors with each of the four photodetectors having the same width dimension, wherein the width dimension of the cycle of four photodetectors determines the resolution of the photodetector array; and wherein the resolution of the coding element and the resolution of the photodetector array are mismatched such that the width dimension of a number, n, of pairs of transparent and opaque sections of the track is equal to the width dimension of the cycle of four photodetectors, where n is an odd integer greater than 1.