US3836257A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for optical detection and/or measurement of movement of diffraction grating
Assignee: Canon Inc
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Filing: 1972-11-20
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Granted: 1974-09-17
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Expires: 1992-11-20
Abstract
Abstract A method for optical detection and/or measurement of movement of a diffraction grating which is characterized in that the vertical movement of the diffraction grating in respect to a standard parallel beam is detected based on variation in interference fringes produced by diffracted waves from the grating moving in the standard parallel beams.
Inventors
- 👤 K Matsumoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 05:21
CPC Classifications
G; G01; G01D; G01D5/00; G01D5/26; G01D5/32; G01D5/34; G01D5/36; G01D5/38; G02; G02B; G02B27/00; G02B27/60
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
119 words
An apparatus for measuring rotation of an object, comprising means for forming a coherent beam, a diffraction grating member mounted on the object and having a plurality of equally spaced grating areas each containing a one dimensional grating, the gratings and successive areas being oriented at angles relative to each other, means for rotating the grating member and the object around a given axis and within the plane of the member, focusing means optically coupled to said grating member for focusing waveforms from the grating member, a focusing plane at the focus of the focusing means, and measuring means at the focal plane for measuring the rotation of the pattern formed by said focusing means and said grating member.
Claim 2
Independent Claim
119 words
An apparatus for measuring rotation of an object, comprising means for forming a coherent beam, a diffraction grating member mounted on the object and having a plurality of equally spaced grating areas each containing a one dimensional grating, the gratings and successive areas being oriented at angles relative to each other, means for rotating the grating member and the object around a given axis and within the plane of the member, focusing means optically coupled to said grating member for focusing waveforms from the grating member, a focusing plane at the focus of the focusing means, and measuring means at the focal plane for measuring the rotation of the pattern formed by said focusing means and said grating member.
Claim 3
Dependent Claim
45 words
An apparatus as in claim 1, wherein N separate grating areas are formed on the grating member and in which the inclinations of the grating on the successive areas of the grating member differ progressively by 360/N from one grating, N being greater than 1.
Claim 4
Dependent Claim
27 words
An apparatus as defined in claim 1, wherein the areas on the grating member are spaced by equal angular intervals around an axis of the grating member.
Claim 5
Dependent Claim
36 words
An apparatus as in claim 1, wherein said measuring means includes optical sensing means in the plane for measuring the recurrence of a point on the pattern as it moves past one point on the plane.
References Cited (Backward Citations)
US3169193A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-09-16 | 1978-03-18 | 1978-09-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-16 | 1982-03-18 | 1982-09-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-16 | 1986-03-18 | 1986-09-17 | $7700.00 | Window Closed / Lapsed |