US3648055A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for determining the relative movement of an object with the use of an optical grating rigidly secured to the object
Assignee: US Philips Corp
•
Filing: 1969-02-04
•
Granted: 1972-03-07
•
Expires: 1989-02-04
Abstract
Abstract The invention relates to an apparatus for determining the relative movement of an object with the use of an optical grating rigidly secured to the object, in which energy emanating from a source of energy interacts with the grating and then is supplied to a system which is sensitive to this energy and converts it into an electric signal which is a periodic function of the movement of the objects characterized in that a second optical grating the periodic direction of which is at right angles to that of the first grating covers this first grating and is substantially coplanar with it.
Inventors
- 👤 Hendrik De Lang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 12:12
CPC Classifications
G; G01; G01D; G01D5/00; G01D5/26; G01D5/32; G01D5/34; G01D5/36; G01D5/38
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
101 words
An apparatus for determining the relative movement of an object in two orthogonal directions, comprising a source of light having a known wavelength, a two-dimensional reflecting diffracting grating attached to the object for diffracting light from the source by reflection into a plurality of ordered beams aligned in two orthogonal directions, means for redirecting the first order beams back to the surface of the grating means whereby the first order beams are diffracted by reflection, means for separating the twice reflected beams corresponding to the two orthogonal directions of the ordered beams, and means for sensing each of the separated beams.
Claim 2
Independent Claim
101 words
An apparatus for determining the relative movement of an object in two orthogonal directions, comprising a source of light having a known wavelength, a two-dimensional reflecting diffracting grating attached to the object for diffracting light from the source by reflection into a plurality of ordered beams aligned in two orthogonal directions, means for redirecting the first order beams back to the surface of the grating means whereby the first order beams are diffracted by reflection, means for separating the twice reflected beams corresponding to the two orthogonal directions of the ordered beams, and means for sensing each of the separated beams.
Claim 3
Dependent Claim
82 words
An apparatus as claimed in claim 1, wherein the source of light comprises a source of plane-polarized light, and wherein the means for separating the twice reflected beams comprises means for rotating the plane of polarization of the first order beams corresponding to a first of the two orthogonal directions of ordered beam alignment by an angle of 90*, and a polarization sensitive beam splitting prism located in the path of the twice-reflected beams between the grating means and the sensing means.
Claim 4
Dependent Claim
77 words
Apparatus as claimed in claim 1, wherein the reflecting diffraction grating means comprises a first plurality of coplanar reflecting surfaces, a second plurality of coplanar reflecting surfaces lying in a plane parallel to the plane of the first plurality of reflecting surfaces and spaced therefrom a distance equal to an odd multiple of 1/4 wavelength of the light from the source, the first plurality of reflecting surfaces and second plurality of reflecting surfaces forming a checkerboard pattern.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-03-07 | 1975-09-06 | 1976-03-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-03-07 | 1979-09-06 | 1980-03-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-03-07 | 1983-09-06 | 1984-03-07 | $7700.00 | Window Closed / Lapsed |