US3744918A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for correlation spectroscopy
Assignee: Pharos AB
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Filing: 1971-04-23
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Granted: 1973-07-10
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Expires: 1991-04-23
Abstract
Abstract Arrangement for correlation spectroscopy by means of the absorption or emission spectrum of a gas. Light from the gas is arranged to be fed to an analyzer, comprising a light transmitting disc arranged in front of a detector. One side of the disc is supplied with an interference filter which within at least one segment of the filter has transmission characteristics as a function of the wavelength within a determined range of wavelengths. The range of wavelengths corresponds to the absorption or emission spectrum of a searched ingredient in the gas. The other parts of said filter have different transmission characteristics. These parts have different transmission characteristics relative to one another and are arranged to be alternatively inserted into the beam path in front of the detector.
Inventors
- 👤 J Jacobsson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 04:40
CPC Classifications
G; G01; G01J; G01J3/00; G01J3/28; G01J3/457; G01J2003/2866
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
245 words
In correlation spectroscopy apparatus wherein the presence of a material is determined by the analysis of the absorption or emission spectrum of a material wherein said spectrum is fed to an analyzer, the improvement wherein said analyzer comprises light detector means positioned to detect a light beam comprising said spectrum, means for passing a predetermined wavelength band of said spectrum to said light detector means and a light filter member disposed to intercept said light beam, said light filter member having a first portion having a light transmission characteristic curve within said wavelength band comprising a plurality of light-transmission maxima and minima and corresponding to the maxima and minima of said predetermined wavelength band of said spectrum of the material being analyzed, having a second portion having a light transmission characteristic curve within said wavelength band having substantially the same shape as the light transmission characteristic curve of said first portion but displaced along the wavelength axis in the direction of shorter wavelength, and having a third portion having a light transmission characteristic curve within said wavelength band having substantially the same shape as the light transmission characteristic curve of said first portion but displaced along the wavelength axis in the direction of longer wavelength, and means to sequentially insert said first, second and third portions in said light beam such that said second and third portions are inserted alternately and said first portion is inserted after said second portion and after said third portion.
Claim 2
Dependent Claim
245 words
In correlation spectroscopy apparatus wherein the presence of a material is determined by the analysis of the absorption or emission spectrum of a material wherein said spectrum is fed to an analyzer, the improvement wherein said analyzer comprises light detector means positioned to detect a light beam comprising said spectrum, means for passing a predetermined wavelength band of said spectrum to said light detector means and a light filter member disposed to intercept said light beam, said light filter member having a first portion having a light transmission characteristic curve within said wavelength band comprising a plurality of light-transmission maxima and minima and corresponding to the maxima and minima of said predetermined wavelength band of said spectrum of the material being analyzed, having a second portion having a light transmission characteristic curve within said wavelength band having substantially the same shape as the light transmission characteristic curve of said first portion but displaced along the wavelength axis in the direction of shorter wavelength, and having a third portion having a light transmission characteristic curve within said wavelength band having substantially the same shape as the light transmission characteristic curve of said first portion but displaced along the wavelength axis in the direction of longer wavelength, and means to sequentially insert said first, second and third portions in said light beam such that said second and third portions are inserted alternately and said first portion is inserted after said second portion and after said third portion.
Claim 3
Dependent Claim
51 words
Correlation spectroscopy apparatus according to claim 1 wherein said filter member has at least two discrete first portions, one of said discrete first portions being inserted in said light beam after said second portion, the other of said discrete first portions being inserted in said light beam after said third portion.
Claim 4
Dependent Claim
24 words
Correlation spectroscopy apparatus according to claim 2 wherein said filter member comprises a member rotatable on an axis generally parallel with said light beam.
Claim 5
Dependent Claim
22 words
Correlation spectroscopy apparatus according to claim 3 wherein the transmission characteristics of said filter member are continuously variable circumferentially of said axis.
Claim 6
Dependent Claim
33 words
Correlation spectroscopy apparatus according to claim 1 further including compensating filter means to compensate for variations in the sensitivity of said detector means as a function of wavelength within said predetermined wavelength band.
Claim 7
Dependent Claim
24 words
Correlation spectroscopy apparatus according to claim 5 wherein said compensating filter is positioned on the side of said filter member remote from said detector.
Claim 8
Dependent Claim
29 words
Correlation spectroscopy apparatus according to claim 2 including a plurality of detector means, the number thereof corresponding to the number of said discrete first portions of said filter member.
Claim 9
Dependent Claim
21 words
Correlation spectroscopy apparatus according to claim 7 further including means to record the total light detected by said plurality of detectors.
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) | 1976-07-09 | 1977-01-08 | 1977-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-09 | 1981-01-08 | 1981-07-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-09 | 1985-01-08 | 1985-07-10 | $7700.00 | Window Closed / Lapsed |