Patent ID: 8044339
Filing Date: 2011-10-25
Classification: G01D

Abstract:
1. An optical encoder comprising: a light source configured to emit an input beam of light; an encoder member positioned to receive the input beam of light from the light source, the encoder member including a plurality of digital diffractive optic regions to optically diffract the input beam of light from the light source to produce output beams of light, at least three of the digital diffractive optic regions being configured such that the output beams of light produced by the at least three of the digital diffractive optic regions have three different intensity distribution patterns; a single photodetector positioned to receive the output beams of light from the digital diffractive optic regions of the encoder member as the encoder member is displaced with respect to the light source and the photodetector, the photodetector being configured to produce signals that indicate intensities of the output beams of light at the photodetector, wherein the encoder member is configured such that the output beams of light produced by the at least three of the digital diffractive optic regions result in three different intensity levels at the photodetector that are indicated in the signals, the signals providing relative displacement information of the encoder member; and a processing unit coupled to the photodetector, the processing unit being configured to process the signals that indicate at least the three different intensity levels exclusively from the photodetector to determine relative displacement of the encoder member.