US4678324A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Range finding by diffraction
Assignee: DEWITT THOMAS D
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Filing: 1985-12-04
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Granted: 1987-07-07
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Expires: 2005-12-04
Abstract
Abstract A method for determining range by correlating the relationship between the distance of a diffraction grating from a monochromatically illuminated target surface with the respective relative displacements of higher order diffraction images from the position of the zero order image as observed through the diffraction grating. An apparatus suggested for embodying the aforesaid method.
Inventors
- 👤 Thomas De Witt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 08:04
CPC Classifications
G; G01; G01C; G01C3/00
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
45 words
A method for determining range by correlating the relationship between the distances of a diffraction grating from an illuminated target surface with the respective relative displacements of high order diffraction images from the position of the respective zero order image as observed through said grating.
Claim 2
Independent Claim
45 words
A method for determining range by correlating the relationship between the distances of a diffraction grating from an illuminated target surface with the respective relative displacements of high order diffraction images from the position of the respective zero order image as observed through said grating.
Claim 3
Dependent Claim
15 words
The method of claim 1 including the step of illuminating said target with monochromatic light.
Claim 4
Independent Claim
66 words
A method for optically determining range comprising: observing light from a distant point-source passing through a diffraction grating whereby the point-source light wavefront is split into multiple wavefronts corresponding to a multiplicity of diffraction images of varying order; and correlating the apparent displacement of higher order diffraction images from their respective zero order image with the physical distance of said point source from said diffraction grating.
Claim 5
Independent Claim
66 words
A method for optically determining range comprising: observing light from a distant point-source passing through a diffraction grating whereby the point-source light wavefront is split into multiple wavefronts corresponding to a multiplicity of diffraction images of varying order; and correlating the apparent displacement of higher order diffraction images from their respective zero order image with the physical distance of said point source from said diffraction grating.
Claim 6
Dependent Claim
16 words
The method of claim 3 including the step of illuminating the point source with monochromatic light.
Claim 7
Independent Claim
83 words
An apparatus for performing the method applied in claims 1 and 3, comprising: a source of monochromatic light to be used to illuminate a target for which data are sought; a diffraction grating which receives target-reflected light and splits its wavefront into multiple order diffraction images; and means for observing and differentiating between the order displacement of said diffraction images whereby their displacement from the zero order image position may be compared to the absolute distance of said diffraction grating from said target.
Claim 8
Dependent Claim
35 words
The invention of claim 5 wherein the diffraction grating comprises equally spaced ruled lines so as to obtain at least two adjacent spacings equal to an integral multiple of one wavelength of said monochromatic light.
Claim 9
Dependent Claim
13 words
The invention of claim 5 wherein the observing means comprises a video camera.
References Cited (Backward Citations)
US3199400A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-07-06 | 1991-01-05 | 1991-07-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-07-06 | 1995-01-05 | 1995-07-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-07-06 | 1999-01-05 | 1999-07-07 | $7700.00 | Window Closed / Lapsed |