Patent ID: 7358481
Filing Date: 2008-04-15
Classification: G01D

Abstract:
1. An encoder comprising: a code pattern comprising multiple first regions and multiple second regions on a carrier comprising a planar surface, said first regions being reflective regions, said first and second regions being relatively positioned in an alternating pattern; and an emitter-detector module comprising a light source that generates light and directs a portion of said generated light at a first side of said carrier and a first detector that detects said light reflected from one of said first regions, wherein each of said first regions comprises a three-dimensional element for directing said light from said light source onto said first detector, said element having a surface that is inclined at an oblique angle with respect to said planar surface and wherein said code pattern moves with respect to said emitter-detector module, wherein said second regions are configured such that said light from said light source incident on said second regions is not directed to said first detector, and wherein said emitter-detector module comprises a second detector that is displaced from said first detector and wherein each of said second regions comprises a second three-dimensional element, which is distinct and separate from said first three-dimensional element, that reflects said light from said light source into said second detector such that said light from said light source incident on said first three-dimensional element of said first regions is exclusively directed to said first detector and said light from said lights source incident on said second three-dimensional element of said second regions is exclusively directed to said second detector.