US5569913A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical displacement sensor
Assignee: Canon Inc
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Filing: 1995-04-25
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Granted: 1996-10-29
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Expires: 2015-04-25
Abstract
Abstract An apparatus for detecting a displacement of a diffraction grating set on a measured object, comprises a light-emitting device, a separation optical element for separating a beam from the light-emitting device into a plurality of beams, a multiplexing optical element for multiplexing light beams diffracted by the diffraction grating from two beams out of the plurality of beams, a first detecting unit for detecting interference light generated when the beams of diffracted light are multiplexed by the multiplexing optical element and outputting a signal related to relative displacement information to the diffraction grating, and a second detecting unit for outputting a signal related to different information from the relative displacement information to the diffraction grating, based on a change in a diffracted light quantity of diffracted light by the diffraction grating from another beam out of the plurality of beams and/or another diffracted light by the diffraction grating from the two beams.
Inventors
- 👤 Koh Ishizuka
- 👤 Yasushi Kaneda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 21:40
CPC Classifications
G; G01; G01D; G01D5/00; G01D5/26; G01D5/32; G01D5/34; G01D5/36; G01D5/38
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
154 words
An apparatus for detecting a displacement of a diffraction grating provided on an object to be measured, comprising: a light-emitting device; a separation optical element for separating a beam from said light-emitting device into a plurality of beams; a multiplexing optical element for multiplexing light beams respectively diffracted by said diffraction grating from two beams out of said plurality of beams; a first detecting unit for detecting interference light generated when the beams of diffracted light are multiplexed by said multiplexing optical element and outputting a signal related to relative displacement information to said diffraction grating; and a second detecting unit for outputting a signal related to information different from said relative displacement information to said diffraction grating, based on a change in a diffracted light quantity of diffracted light by said diffraction grating from another beam from said plurality of beams and/or another diffracted light by said diffraction grating from said two beams.
Claim 2
Independent Claim
154 words
An apparatus for detecting a displacement of a diffraction grating provided on an object to be measured, comprising: a light-emitting device; a separation optical element for separating a beam from said light-emitting device into a plurality of beams; a multiplexing optical element for multiplexing light beams respectively diffracted by said diffraction grating from two beams out of said plurality of beams; a first detecting unit for detecting interference light generated when the beams of diffracted light are multiplexed by said multiplexing optical element and outputting a signal related to relative displacement information to said diffraction grating; and a second detecting unit for outputting a signal related to information different from said relative displacement information to said diffraction grating, based on a change in a diffracted light quantity of diffracted light by said diffraction grating from another beam from said plurality of beams and/or another diffracted light by said diffraction grating from said two beams.
Claim 3
Dependent Claim
43 words
The apparatus according to claim 1, wherein said second detecting unit outputs a signal related to an origin of said diffraction grating, a position of a grating edge of said diffraction grating, or an output from said light-emitting device as said different information.
Claim 4
Dependent Claim
68 words
The apparatus according to claim 1, wherein said separation optical element has a diffraction grating for separation of beam and said second detecting unit outputs the signal related to said different information, based on a change in a diffracted light quantity of re-diffracted light by said diffraction grating from diffracted light coming from said diffraction grating for separation of beam and not used by said first detecting unit.
Claim 5
Dependent Claim
23 words
The apparatus according to claim 1, wherein said first detecting unit and second detecting unit have respective detectors provided on a same surface.
Claim 6
Dependent Claim
37 words
The apparatus according to claim 1, wherein said second detecting unit outputs a signal related to a position of a grating edge of said diffraction grating and has means for generating an alarm, based on said signal.
Claim 7
Dependent Claim
134 words
The apparatus according to claim 1, wherein said separation optical element has a diffraction grating for separation of beam and wherein said second detecting unit outputs signals respectively related to an origin and a position of a grating edge of said diffraction grating, based on a diffracted light quantity change of re-diffracted light by said diffraction grating from diffracted light coming from said diffraction grating for separation of beam and not used by said first detecting unit, and outputs a signal related to an output from said light-emitting device, based on a diffracted light quantity change of re-diffracted light not used by said first detecting unit out of the re-diffracted light by said diffraction grating from diffracted light coming from said diffraction grating for separation of beam and used by said first detecting unit.
Claim 8
Dependent Claim
35 words
The apparatus according to claim 1, wherein said second detecting unit outputs a signal related to an output from said light-emitting device and further has means for controlling the light-emitting device, based on said signal.
Claim 9
Dependent Claim
170 words
A drive system comprising: a diffraction grating provided on an object to be measured; a light-emitting device; a separation optical element for separating a beam from said light-emitting device into a plurality of beams; a multiplexing optical element for multiplexing light beams diffracted by said diffraction grating from two beams out of said plurality of beams; a first detecting unit for detecting interference light generated when the beams of diffracted light are multiplexed by said multiplexing optical element and outputting a signal related to relative displacement information to said diffraction grating; a second detecting unit for outputting a signal related to information different from said relative displacement information to said diffraction grating, based on a change in a diffracted light quantity of diffracted light by said diffraction grating from another beam from said plurality of beams and/or another diffracted light by said diffraction grating from said two beams; and a position control portion for executing relative drive of said measured object, based on an output from said first detecting unit.
Claim 10
Dependent Claim
170 words
A drive system comprising: a diffraction grating provided on an object to be measured; a light-emitting device; a separation optical element for separating a beam from said light-emitting device into a plurality of beams; a multiplexing optical element for multiplexing light beams diffracted by said diffraction grating from two beams out of said plurality of beams; a first detecting unit for detecting interference light generated when the beams of diffracted light are multiplexed by said multiplexing optical element and outputting a signal related to relative displacement information to said diffraction grating; a second detecting unit for outputting a signal related to information different from said relative displacement information to said diffraction grating, based on a change in a diffracted light quantity of diffracted light by said diffraction grating from another beam from said plurality of beams and/or another diffracted light by said diffraction grating from said two beams; and a position control portion for executing relative drive of said measured object, based on an output from said first detecting unit.
References Cited (Backward Citations)
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