Patent ID: 7026604
Filing Date: 2006-04-11
Classification: G01D

Abstract:
1. An encoder comprising: a first array of n photodetectors, where n>2, each photodetector being characterized by a width d; and a code strip imaging system for generating an image from a code strip on said first array, said image comprising alternating dark and light stripes, said stripes having a width of D, said dark stripes having a lower luminosity than said light stripes, wherein nd=(n−1)D, said code strip image moving in a first direction with respect to said first array, said distances d and D being measured in a direction parallel to said first direction, wherein said first array of photodetectors is divided into a second array of photodetectors and a third array of photodetectors, each photodetector in said second array and said third array having a width d, wherein said third array of photodetectors is offset from said second array of photodetectors in said first direction, and wherein said third array of photodetectors is offset from said second array of photodetectors in a direction orthogonal to said first direction.