US3700332A
Expired / Lapsed
US
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Spectral analysis using a modulating mask transmitting selected spectral lines and reference bands
Assignee: Comstock and Wescott Inc
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Filing: 1971-03-05
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Granted: 1972-10-24
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Expires: 1991-03-05
Abstract
Abstract For detecting specific gases in an automobile exhaust selected lines of the exhaust gas absorption spectrum and reference bands of the spectrum close to the lines are chopped by a mask at the spectral plane so that the light flux from the lines and bands are transmitted at different times. The flux of the lines and bands are also encoded by the chopping mask or a successive encoding mask and applied to a single photodetector which produces a series of electrical values representing the flux of the selected spectral lines.
Inventors
- 👤 John A Decker Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 11:35
CPC Classifications
G; G01; G01J; G01J3/00; G01J3/28; G01J3/457; G01J2003/2866
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
141 words
Optical apparatus for measuring the light flux from a plurality of selected lines in a spectrum having at least one band of predetermined spectroscopic characteristic proximate to the selected lines, each line and its proximate band being a set, comprising: modulator means for repeatedly transmitting and obscuring the flux from said selected lines and proximate band concomitantly including portions disposed to transmit flux from at least two lines of different sets simultaneously aNd a separate portion for transmitting flux from a band at another time, and further including encoding means selectively transmitting flux from both the line and band of each set, photoelectric means for sensing the modulated flux, and means for projecting the modulated flux from said line and band on said photoelectric means, thereby to cause said means to produce electrical values representing the flux of the selected lines.
Claim 2
Dependent Claim
141 words
Optical apparatus for measuring the light flux from a plurality of selected lines in a spectrum having at least one band of predetermined spectroscopic characteristic proximate to the selected lines, each line and its proximate band being a set, comprising: modulator means for repeatedly transmitting and obscuring the flux from said selected lines and proximate band concomitantly including portions disposed to transmit flux from at least two lines of different sets simultaneously aNd a separate portion for transmitting flux from a band at another time, and further including encoding means selectively transmitting flux from both the line and band of each set, photoelectric means for sensing the modulated flux, and means for projecting the modulated flux from said line and band on said photoelectric means, thereby to cause said means to produce electrical values representing the flux of the selected lines.
Claim 3
Dependent Claim
29 words
Apparatus according to claim 1 wherein said modulator means comprises light transmitting elements spaced in a relation corresponding to the distribution of said lines and band in said spectrum.
Claim 4
Dependent Claim
13 words
Apparatus according to claim 2 wherein said elements have different flux transmitting capacities.
Claim 5
Dependent Claim
14 words
Apparatus according to claim 3 wherein at least one of said capacities are adjustable.
Claim 6
Dependent Claim
15 words
Apparatus according to claim 2 wherein said elements correspond to selected lines of the spectrum.
Claim 7
Dependent Claim
15 words
Apparatus according to claim 5 wherein said selected lines are characteristic of predetermined chemical compounds.
Claim 8
Dependent Claim
11 words
Apparatus according to claim 6 wherein the predetermined compounds are gases.
Claim 9
Dependent Claim
14 words
Apparatus according to claim 7 wherein the gases are those present in combustion products.
Claim 10
Dependent Claim
18 words
Apparatus according to claim 1 wherein said modulator means is disposed in the image plane of said spectrum.
Claim 11
Dependent Claim
35 words
Apparatus according to claim 1 in combination with spectral dispersion means producing a spectrum in a plane, said modulator means being disposed at said plane and forming an exit aperture for the spectral dispersion means.
Claim 12
Dependent Claim
46 words
Apparatus according to claim 1 wherein said modulator means comprises a mask movable transversely of the spectrum and having slits at the image of said line and of said band respectively, the line and band slits being offset in the direction of motion of the mask.
Claim 13
Dependent Claim
55 words
Apparatus according to claim 1 wherein said modulator means comprises a stationary mask and a movable reflector for moving the spectrum transversely of the mask, said mask having slits at the image of said line and of said band respectively, the line and band slits being offset in the direction of movement of the spectrum.
Claim 14
Dependent Claim
67 words
Apparatus according to claim 1 wherein said modulator means comprises a rotating disk having a set of slits for each said line and band, the slits being rotatable with the disk through the image of the line and band respectively, the slits of both sets having the same angular spacing around the disk, and the slits of one set being angularly offset from the slits of the
Claim 15
Dependent Claim
14 words
Apparatus according to claim 1 wherein said photoelectric means comprises a single photoelectric device.
Claim 16
Dependent Claim
29 words
Apparatus according to claim 14 wherein said photoelectric means has a response characteristic detecting substantially only the difference between the flux from a line and from its proximate band.
Claim 17
Dependent Claim
13 words
Apparatus according to claim 15 wherein said photodetector has low direct current response.
Claim 18
Dependent Claim
26 words
Apparatus according to claim 1 wherein the light transmitting element for said one band is proximate to the light transmitting element for both said two lines.
Claim 19
Dependent Claim
40 words
Apparatus according to claim 1 wherein said encoding means comprises a plurality of arrays of flux transmitting elements and means for moving the encoding means to bring successive arrays of elements into flux transmitting relation with said lines and bands.
Claim 20
Dependent Claim
97 words
Apparatus according to claim 1 wherein said modulator means comprises a first light modulator having spaced elements for transmitting flux from respective lines and bands, and means producing relative movement between said modulator and said lines and bands, and an encoding modulator having a plurality of arrays of elements dimensioned to transmit flux from both the line and band of each set, and means for producing relative movement between the encoding modulator and said lines and bands to bring successive arrays of elements into flux transmitting relation with different combinations of sets of said lines and Bands.
Claim 21
Dependent Claim
67 words
Apparatus according to claim 1 wherein said modulating means comprises a moving mask having a plurality of sets of flux transmitting elements, one set for each line and each proximate band, the elements of each line set and its proximate band set being spaced at the same intervals in the direction of movement to modulate flux from each line and its proximate band at the same frequency.
Claim 22
Dependent Claim
23 words
Apparatus according to claim 20 wherein the elements for different lines are differently spaced to modulate flux from different lines at different frequencies.
Claim 23
Dependent Claim
36 words
Apparatus according to claim 20 wherein the elements for each line and its proximate band are displaced in said direction of movement so as to transmit flux from the line and band during different time intervals.
Claim 24
Dependent Claim
27 words
Apparatus according to claim 1 wherein said photoelectric means comprises a single photoelectric device receiving transmitted and encoded flux from said plurality of lines and band simultaneously.
Claim 25
Dependent Claim
24 words
Apparatus according to claim 23 wherein said photoelectric means comprises a detector of the difference between the flux of the lines and proximate bands.
Claim 26
Independent Claim
114 words
The method of measuring the light flux of a plurality of selected lines of a dispersed spectrum which comprises masking the spectrum except for the selected lines and at least one wavelength band proximate to said lines, each line and its proximate band constituting a set, periodically masking and transmitting flux from said lines and band, the flux from said lines being transmitted at different times than the flux from each band, optically encoding the periodically transmitted flux from the lines and bands in sets each including a line and a band, and photoelectrically detecting the periodically transmitted and encoded flux, to produce an electrical signal representative of the flux of the selected lines.
Claim 27
Independent Claim
114 words
The method of measuring the light flux of a plurality of selected lines of a dispersed spectrum which comprises masking the spectrum except for the selected lines and at least one wavelength band proximate to said lines, each line and its proximate band constituting a set, periodically masking and transmitting flux from said lines and band, the flux from said lines being transmitted at different times than the flux from each band, optically encoding the periodically transmitted flux from the lines and bands in sets each including a line and a band, and photoelectrically detecting the periodically transmitted and encoded flux, to produce an electrical signal representative of the flux of the selected lines.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-10-24 | 1976-04-24 | 1976-10-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-24 | 1980-04-24 | 1980-10-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-24 | 1984-04-24 | 1984-10-24 | $7700.00 | Window Closed / Lapsed |