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US 8,044,339 B2Granted
Intensity-based optical encoder using digital diffractive optic regions
AssigneeArcus Technology, Inc.
InventorsChristopher C. Chang, Bernard C. Kress
Life of this patent
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Abstract
An optical encoder and method for measuring displacement information using an optical encoder uses an encoder member with multiple digital diffractive optic regions to optically diffract an incident beam of light to produce output beams of light having intensity distribution patterns, which are used to generate electrical signals that provide relative displacement information of the encoder member.
Claims20
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.
2 more elements
A method for measuring displacement information using an optical encoder, the method comprising:
- emitting a beam of light from a light source of the optical encoder toward an encoder member of the optical encoder;
- optically diffracting the input beam of light received at different digital diffractive optic regions of the encoder member to produce output beams of light as the encoder member is relatively displaced with respect to the light source and a single photodetector of the optical encoder, wherein at least three of the different digital diffractive optic regions are configured to produce the output beams of light having three different intensity distribution patterns, the output beams of light resulting in at least three different intensity levels at the photodetector;
- producing electrical signals at the photodetector in response to the output beams of light received at the photodetector, the electrical signals indicating at least the three different intensity levels resulting from the output beams of light received at the photodetector from the at least three of the different digital diffractive optic regions and providing relative displacement information of the encoder member;
- and
- processing the electrical signals that indicate at least the three different intensity levels exclusively from the photodetector to determine relative displacement of the encoder member.
2 more elements
Dependencies are inferred from the claim text.