US3867035A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photoelectric step marker
Assignee: Ernst Leitz Wetzlar GmbH
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Filing: 1973-12-17
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Granted: 1975-02-18
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Expires: 1993-12-17
Abstract
Abstract A photoelectric step marker for the measurement of the amplitude and sign of object displacements in two coordinates. The step marker comprises a measuring grating divided in orthogonal directions and being displaceable with the object. A linear grating is associated with each direction and a spatial frequency filter is used for filtering out for each direction the light resulting from diffraction at the measuring grating. Optical means are provided to produce an optical path difference of lambda /4 between two orthogonal directions of polarisation in the filtered out light; and a polarizing splitter with associated photoelectric receivers is arranged in the ray path of each direction for obtaining electrical signals corresponding to the object displacement.
Inventors
- 👤 Dietmar Kaul
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 19:13
CPC Classifications
G; G01; G01D; G01D5/00; G01D5/26; G01D5/32; G01D5/34; G01D5/36; G01D5/38
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
159 words
A photoelectric step marker for the measurement of the amplitude and sign of object displacements in two coordinates, comprising: a. a measuring grating, which is divided in two mutually orthogonal directions and which is displaceable with the object; b. two separate linear gratings each associated with a respective one of the two directions; c. a spatial frequency filter, which for each of the two directions filters out the light resulting from diffraction at the measuring grating and which is arranged within an optical system disposed between the measuring grating and the linear gratings, the spatial frequency filter comprising lightdeflecting optical components for the separation of the ray paths associated with each of the two directions; d. optical means to produce an optical path difference of lambda /4 between two mutually orthogonal directions of polarisation in the filtered-out light; and e. an individual polarising splitter with associated photoelectric receivers in the ray path associated with each of the two directions.
Claim 2
Dependent Claim
159 words
A photoelectric step marker for the measurement of the amplitude and sign of object displacements in two coordinates, comprising: a. a measuring grating, which is divided in two mutually orthogonal directions and which is displaceable with the object; b. two separate linear gratings each associated with a respective one of the two directions; c. a spatial frequency filter, which for each of the two directions filters out the light resulting from diffraction at the measuring grating and which is arranged within an optical system disposed between the measuring grating and the linear gratings, the spatial frequency filter comprising lightdeflecting optical components for the separation of the ray paths associated with each of the two directions; d. optical means to produce an optical path difference of lambda /4 between two mutually orthogonal directions of polarisation in the filtered-out light; and e. an individual polarising splitter with associated photoelectric receivers in the ray path associated with each of the two directions.
Claim 3
Dependent Claim
30 words
A photoelectric step marker as claimed in claim 1, wherein the measuring grating is constructed as a phase grating and wherein six photoelectric receivers are associated with each polarising splitter.
Claim 4
Dependent Claim
28 words
A photoelectric step marker as claimed in claim 1, wherein the optical means to produce the path difference are provided in the range of the spatial frequency filter.
Claim 5
Dependent Claim
32 words
A photoelectric step marker as claimed in claim 1, wherein the optical means to produce the path difference are provided in the paths between the spatial frequency filter and the linear gratings.
References Cited (Backward Citations)
US3482107A
Cited
US3756723A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-02-17 | 1978-08-19 | 1979-02-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-17 | 1982-08-19 | 1983-02-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-17 | 1986-08-19 | 1987-02-18 | $7700.00 | Window Closed / Lapsed |