Patent Number: 7,465,917

Title: Absolute encoder utilizing light of different wavelengths to reduce cross-talk

Abstract: An encoder having a code scale, an illumination system, and a plurality of photodetectors is disclosed. The code scale has a plurality of tracks that are illuminated by the illumination system. Each photodetector receives light from a corresponding one of the tracks and generates a signal indicative of a quantity of light received from that track. Each photodetector is limited to detecting light in a band of wavelengths corresponding to that track. Each track generates light in a band of wavelengths corresponding to that track, and the band of wavelengths corresponding to one of the tracks is different from the band of wavelengths corresponding to the tracks that are next to that track. The tracks can include alternating reflective and absorptive stripes, alternating transmissive and reflective stripes, or alternating luminescent and absorptive stripes.

Inventors: Chin; Yee Loong (Taman Pinji Mewah, MY), Ng; Kean Foong (Penang, MY)

Assignee: Avago Technologies General IP (Singapore) Pte. Ltd.

International Classification: G01D 5/34 (20060101)

Expiration Date: 2021-12-16 0:00:00