Patent ID: 7490771
Filing Date: 2009-02-17
Classification: G06K

Abstract:
1. An encoder comprising: a code strip comprising alternating reflective and opaque stripes; an emitter-detector module comprising a housing, a light source and a photodetector, light from said light source illuminating said code strip and light from said code strip being incident on said photodetector; a first lens insert comprising a first lens that processes light generated by said light source before said light reaches said code strip and a second lens insert comprising a second lens that processes light after said light is reflected from said code strip, wherein said first lens insert mates with said housing at a first vertical location to position said first lens at a predetermined point relative to said light source, and said second lens insert mates with said housing at a second vertical location different than said first vertical location to position said second lens at a predetermined point relative to said photodetector, wherein said code strip moves relative to said emitter-detector module thereby causing said photodetector to generate a signal that alternates between first and second states during the operation of said encoder, and wherein said light source and said photodetector are mounted in a fixed position on a same side of said housing opposite to said code strip, with each of said first lens insert and said second lens insert being removably mounted on said housing therebetween.