US5506681A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for detecting a reference position and displacement detector using the same
Assignee: Canon Inc
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Filing: 1994-01-25
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Granted: 1996-04-09
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Expires: 2014-01-25
Abstract
Abstract A displacement detector includes a light generation source for generating light, a scale to be irradiated by the generated light and displaceable relative to the irradiated light, a first detection device having a photo-sensing element for detecting light transmitted through the scale for detecting displacement information of the scale, a mark having a focusing or light-condensing function formed integrally with the scale, and a second detection device having a photo-sensing element for sensing the light-condensed by the mark for detecting a reference position of the scale.
Inventors
- 👤 Masahiko Igaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 21:43
CPC Classifications
G; G01; G01D; G01D5/00; G01D5/26; G01D5/32; G01D5/34; G01D5/36; G01D5/366
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
128 words
A displacement detector, comprising: light generation means for generating a light; a cylindrical rotary scale having a grating formed on a side plane thereof, wherein the light is irradiated to a first portion on the side plane and directed to a second portion different from the first portion; first detection means for detecting the light irradiated through said grating in the second portion to detect displacement information of said scale; a light-condensing portion provided on said scale separately from said grating; splitting means for spitting the light beam from said light generation means to direct the split light beam to said light-condensing portion through the first portion; and second detection means for detecting the light condensed by said light-condensed portion to detect a reference position of said scale.
Claim 2
Dependent Claim
128 words
A displacement detector, comprising: light generation means for generating a light; a cylindrical rotary scale having a grating formed on a side plane thereof, wherein the light is irradiated to a first portion on the side plane and directed to a second portion different from the first portion; first detection means for detecting the light irradiated through said grating in the second portion to detect displacement information of said scale; a light-condensing portion provided on said scale separately from said grating; splitting means for spitting the light beam from said light generation means to direct the split light beam to said light-condensing portion through the first portion; and second detection means for detecting the light condensed by said light-condensed portion to detect a reference position of said scale.
Claim 3
Dependent Claim
15 words
A displacement detector according to claim 1, wherein said splitting means comprises a diffraction grating.
Claim 4
Dependent Claim
14 words
A displacement detector according to claim 1, wherein said light-condensing portion comprises a lens.
Claim 5
Dependent Claim
15 words
A displacement detector according to claim 1, wherein said light-condensing portion comprises a zone plate.
Claim 6
Dependent Claim
20 words
A displacement detector according to claim 1, wherein said light-condensing portion is provided on the side plane of said scale.
Claim 7
Dependent Claim
33 words
A displacement detector according to claim 1, wherein said scale comprises a light transmissive grating having a concave-convex surface inclined to an incident light, with said grating being arranged at a constant pitch.
Claim 8
Dependent Claim
16 words
A displacement detector according to claim 1, wherein said light generation means comprises a semiconductor laser.
Claim 9
Dependent Claim
15 words
A displacement detector according to claim 1, wherein said light generation means comprises an LED.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-04-09 | 1999-10-09 | 2000-04-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-04-09 | 2003-10-09 | 2004-04-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-04-09 | 2007-10-09 | 2008-04-09 | $7700.00 | Window Closed / Lapsed |