US3770958A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Infrared radiation detection by a matched system
Assignee: Honeywell Inc
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Filing: 1972-01-05
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Granted: 1973-11-06
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Expires: 1992-01-05
Abstract
Abstract An infrared radiation detection system has a filter capable of transmitting infrared radiation in a passband of wavelengths common to a range of wavelengths in which a cooled detection system sensor is capable of sensing radiation. The filter is matched to the sensor by having a low emissivity in those continuous ranges of wavelengths (1) across which any detector element in the sensor is sensitive to impinging infrared radiation and (2) which overlap in any part any filter passband. The filter positioned in the field of view of the sensor so matched does not appear as a noise source to the sensor despite the filter not being cooled.
Inventors
- 👤 B Krakow
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 20:35
CPC Classifications
G; G01; G01J; G01J5/00; G01J5/60; G01J5/602
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
169 words
A system for infrared radiation detection comprising: sensing means of the photon detector type sensitive to impinging infrared radiation in a spectrum of wavelengths having at least one detector element with a substantial effective sensitivity over a first subrange of wavelengths included within said spectrum, an enclosure having said sensing means mounted therein and provided with aperture means such that radiation originating from outside of said enclosure received therein is limited to being essentially radiation received through an aperture in said aperture means, cooling means to maintain interior surfaces of said enclosure near said sensing means and interior surfaces of said aperture means at a predetermined first temperature, and radiation filter means having a first filtering member selectively positionable across said aperture to transmit radiation to said enclosure of wavelengths included at least in part within said first subrange of wavelengths with said first filtering member and other portions of said radiation filter means exposed to said sensing means therewith having small emissivities over said first subrange of wavelengths.
Claim 2
Independent Claim
169 words
A system for infrared radiation detection comprising: sensing means of the photon detector type sensitive to impinging infrared radiation in a spectrum of wavelengths having at least one detector element with a substantial effective sensitivity over a first subrange of wavelengths included within said spectrum, an enclosure having said sensing means mounted therein and provided with aperture means such that radiation originating from outside of said enclosure received therein is limited to being essentially radiation received through an aperture in said aperture means, cooling means to maintain interior surfaces of said enclosure near said sensing means and interior surfaces of said aperture means at a predetermined first temperature, and radiation filter means having a first filtering member selectively positionable across said aperture to transmit radiation to said enclosure of wavelengths included at least in part within said first subrange of wavelengths with said first filtering member and other portions of said radiation filter means exposed to said sensing means therewith having small emissivities over said first subrange of wavelengths.
Claim 3
Dependent Claim
110 words
The system of claim 1 wherein said sensing means comprises a plurality of detector elements each having at least one cutoff wavelength value and each positioned successively in a path followed by radiation received through said aperture and positioned in alignment with one another along an axis in sequence according to increasing cutoff wavelength values, beginning with a first detector element, such that said spectrum of wavelengths is divided into a plurality of subranges of wavelengths each determined approximately by a pair of said cutoff wavelength values with said first suBrange of wavelengths being one of said plurality of subranges of wavelengths, said first detector element being nearest said aperture.
Claim 4
Dependent Claim
19 words
The system of claim 1 wherein means are provided to maintain said sensing means at a predetermined second temperature.
Claim 5
Dependent Claim
25 words
The system of claim 1 wherein said first filtering member is a separate filter element capable of transmitting radiation in a fixed range of wavelengths.
Claim 6
Dependent Claim
29 words
The system of claim 1 wherein said first filtering member is a continuously variable filter capable of transmitting radiation through a section thereof thereby determining a passband of wavelengths.
Claim 7
Dependent Claim
88 words
The system of claim 2 wherein said first filtering member is also capable of transmitting radiation at least in part within at least one of said subranges of wavelengths other than said first subrange of wavelengths with said first filtering member and other portion of said radiation filtering means exposed to said sensing means therewith having small emissivities over any of said subranges of wavelengths wherein said first filtering member is capable of transmitting radiation and wherein a said detector element being monitored has a substantial effective sensitivity.
Claim 8
Dependent Claim
123 words
The system of claim 2 wherein said radiation filter means has a plurality of filtering members each being selectively positionable across said aperture to transmit radiation to said enclosure including a second filtering member capable of transmitting radiation in a range of wavelengths included at least in part within one of said subranges of wavelengths other than said first subrange of wavelengths, and with any one of said plurality of filtering members and other portions of said radiation filtering means exposed to said sensing means therewith having small emissivities in any of said subranges of wavelengths wherein that one of said plurality of filtering members is capable of transmitting radiation and wherein a said detector element being monitored has a substantial effective sensitivity.
Claim 9
Dependent Claim
14 words
The system of claim 2 wherein said first detector element is a blocking element.
Claim 10
Dependent Claim
24 words
The system of claim 6 wherein all of said detector elements do not have an effective sensitivity in at least one of said subranges.
Claim 11
Dependent Claim
12 words
The system of claim 6 wherein said detector elements are selectively monitored.
Claim 12
Dependent Claim
12 words
The system of claim 6 wherein said detector elements are photoconductive types.
Claim 13
Dependent Claim
25 words
The system of claim 7 wherein said second filtering member is a separate filter element capable of transmitting radiation in a fixed range of wavelengths.
Claim 14
Dependent Claim
29 words
The system of claim 7 wherein said second filtering member is a continuously variable filter capable of transmitting radiation through a section thereof thereby determining a passband of wavelengths.
Claim 15
Dependent Claim
24 words
The system of claim 7 wherein all of said detector elements do not have an effective sensitivity in at least one of said subranges.
Claim 16
Dependent Claim
12 words
The system of claim 7 wherein said detector elements are selectively monitored.
Claim 17
Dependent Claim
12 words
The system of claim 7 wherein said detector elements are photoconductive types.
Claim 18
Dependent Claim
25 words
The system of claim 13 wherein means are provided for adjusting the size of said section through which radiation reaching said sensing means is transmitted.
Claim 19
Independent Claim
230 words
A system for infrared radiation detection comprising sensing means of the photon detector type sensitive to impinging infrared radiation in a spectrum of wavelengths, said sensing means comprising a plurality of detector elements each having at least one cutoff wavelength value and each positioned successively in a path followed by radiation received through an aperture and positioned in alignment with one another along an axis in sequence according to increasing cutoff wavelength values, beginning with a first detector element, such that said spectrum of wavelengths is divided into a plurality of subranges of wavelengths each determined approximately by a pair of said cutoff wavelength values including a first sub-range of wavelengths, said first detector element being nearest said aperture; an enclosure having said sensing means mounted therein and provided with aperture means such that radiation originating from outside of said enclosure received therein is limited to being essentially radiation received through said aperture located in said aperture means; and radiation filter means having an interference filter as a first filtering member selectively positionable across said aperture to transmit radiation to said enclosure in at least one preselected wavelength range included at least in part within said first subrange of wavelengths and to substantially block transmission of radiation to said enclosure of wavelengths included in said first subrange of wavelengths but which are not included in said preselected ranges of wavelengths.
Claim 20
Independent Claim
230 words
A system for infrared radiation detection comprising sensing means of the photon detector type sensitive to impinging infrared radiation in a spectrum of wavelengths, said sensing means comprising a plurality of detector elements each having at least one cutoff wavelength value and each positioned successively in a path followed by radiation received through an aperture and positioned in alignment with one another along an axis in sequence according to increasing cutoff wavelength values, beginning with a first detector element, such that said spectrum of wavelengths is divided into a plurality of subranges of wavelengths each determined approximately by a pair of said cutoff wavelength values including a first sub-range of wavelengths, said first detector element being nearest said aperture; an enclosure having said sensing means mounted therein and provided with aperture means such that radiation originating from outside of said enclosure received therein is limited to being essentially radiation received through said aperture located in said aperture means; and radiation filter means having an interference filter as a first filtering member selectively positionable across said aperture to transmit radiation to said enclosure in at least one preselected wavelength range included at least in part within said first subrange of wavelengths and to substantially block transmission of radiation to said enclosure of wavelengths included in said first subrange of wavelengths but which are not included in said preselected ranges of wavelengths.
Claim 21
Dependent Claim
33 words
The system of claim 1 wherein cooling means are provided to maintain interior surfaces of said enclosure near said sensing means and interior surfaces of said aperture means at a predetermined first temperature.
Claim 22
Dependent Claim
62 words
The system of claim 18 wherein said preselected wavelength range is at least in part within a second subrange of wavelengths and said radiation filter means substantially blocks transmission of radiation to said enclosure of wavelengths in any said subrange of wavelengths wherein said preselected range of wavelengths occur and wherein a said detector element being monitored has a substantially effective sensitivity.
Claim 23
Dependent Claim
115 words
The system of claim 18 wherein said radiation filter means has a plurality of interference filters as filtering members each being selectively positionable across said aperture to transmit radiation to said enclosure including a second filtering member capable of transmitting radiation in a range of wavelengths included at least in part within one of said subranges of wavelengths other than said first subrange of wavelengths, and with any one of said filtering members substantially blocking transmission of radiation to said enclosure of wavelengths in any of said subranges of wavelengths wherein that one of said filtering members is capable of transmitting radiation and wherein a said detector element being monitored has a substantially effective sensitivity.
References Cited (Backward Citations)
US3662171A
Cited
US3660659A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-05 | 1977-05-07 | 1977-11-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-05 | 1981-05-07 | 1981-11-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-05 | 1985-05-07 | 1985-11-06 | $7700.00 | Window Closed / Lapsed |