US4965447A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Chopper for staring infrared systems
Assignee: Atos Origin IT Services Inc
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Filing: 1988-07-28
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Granted: 1990-10-23
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Expires: 2008-07-28
Abstract
Abstract Incident infrared radiation is focussed through a rotatable disk of germam onto a detector array. The disk has a thickness many times the wavelengths of the incident radiation and is partly covered with a pattern of germanium one-half wavelength of some preselected wavelength of the incident radiation. The pattern is a regular array of mesas, and acts as a phase grating which diffracts incident radiation. The diffracted (or blurred) image on the detector array is used as a reference level for background suppression.
Inventors
- 👤 Vincent T. Bly
- 👤 Conrad W. Terrill
- 👤 Donna J. Advena
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 21:33
CPC Classifications
G; G01; G01D; G01D5/00; G01D5/26; G01D5/32; G01D5/34; G01D5/347; G01D5/34707; G01D5/36; G01D5/38; G01D5/40; H; H04; H04N; H04N23/00; H04N23/20
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
114 words
An improved chopper for a detector array of a narrow band of electromagnetic radiation, wherein the chopper is in the form of a disk adjacent to said detector and whose thickness is many times the wavelengths of radiation in said band and which is tranparent to said radiation and which is partially covered with a pattern on one side, wherein said pattern has an optical thickness of one-half wavelength for a particular one of said wavelengths and is transparent to said radiation, wherein the disk is rotatable about an axis parallel to the optical path between said radiation and said detector to alternately interpose its pattern covered and uncovered portions in said optical path.
Claim 2
Dependent Claim
114 words
An improved chopper for a detector array of a narrow band of electromagnetic radiation, wherein the chopper is in the form of a disk adjacent to said detector and whose thickness is many times the wavelengths of radiation in said band and which is tranparent to said radiation and which is partially covered with a pattern on one side, wherein said pattern has an optical thickness of one-half wavelength for a particular one of said wavelengths and is transparent to said radiation, wherein the disk is rotatable about an axis parallel to the optical path between said radiation and said detector to alternately interpose its pattern covered and uncovered portions in said optical path.
Claim 3
Dependent Claim
21 words
The chopper as set forth in claim 1 wherein said band is for infrared, and said disk and pattern are germanium.
Claim 4
Dependent Claim
19 words
The chopper as set forth in claim 1 wherein said pattern is in the area between two archemidian spirals.
References Cited (Backward Citations)
US4322620A
Cited
US4814602A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-10-22 | 1994-04-23 | 1994-10-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-10-22 | 1998-04-23 | 1998-10-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-10-22 | 2002-04-23 | 2002-10-23 | $7700.00 | Window Closed / Lapsed |