Patent ID: 7348545
Filing Date: 2008-03-25
Classification: G01D

Abstract:
1. An optical encoder system, comprising: a codewheel pattern medium comprising a disk containing a double-sided code pattern, wherein a first portion of the double-sided code pattern is contained in a first set of concentric reflective tracks disposed on a first side of the disk and a second portion of the double-side code is contained in a second set of concentric reflective tracks disposed directly opposing the first set of concentric reflective tracks on a second opposing side of the disk; a first optical encoder disposed toward the first side of the disk, the first optical encoder configured to produce a first output signal comprising the first portion of the double-side code pattern; and a second optical encoder disposed toward the second opposing side of the disk, the second optical encoder configured to produce a second output signal comprising the second portion of the double-side code pattern.