US3836254A
Expired / Lapsed
US
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Optical correlator with optimized maximum and minimum correlation masks
Assignee: Smiths Detection Toronto Ltd
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Filing: 1969-12-15
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Granted: 1974-09-17
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Expires: 1989-12-15
Abstract
Abstract An optical correlator having an optical wedge or other device for producing a spatially dispersed pattern of light in a plane, the light being characterized by zones of relatively high intensity and low intensity corresponding to spectra present in the incident light or the Fourier transform thereof. The dispersed light is alternately or simultaneously passed through a first mask having a pattern of opaque and transparent regions or lines positioned to correlate with the zones of relatively high intensity light and a second mask having a plurality of opaque and transparent regions or lines positioned to correlate with the relatively low intensity zones of light. A photodetector examines the light passing through the masks and produces and output signal which can be analyzed to determine the character of the incident radiation.
Inventors
- 👤 A Barringer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:35
CPC Classifications
G; G01; G01J; G01J3/00; G01J3/28; G01J3/457; G01J2003/2866
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
199 words
Apparatus for analyzing incident radiation comprising: a. first and second means for spatially dispersing said incident radiation to form a dispersion of radiation in a plane, said dispersion being composed of radiation zones of relatively low intensity characteristic of a particular substance when the characteristic spectra of said substance are present in the incident radiation, b. first mask means positioned in said plane and in the path of light emerging from said first dispersing means, said first mask means having a plurality of relatively opaque and transparent regions, said regions being correlative with said relatively high intensity zones of said dispersion, c. second mask means positioned in said plane and in the path of light emerging from said second dispersing means, said second mask means having a plurality of relatively opaque and transparent regions, said regions being correlative with said relatively low intensity zones of said dispersion, d. photodetector means positioned to receive light emerging from said first and second mask means, said photodetector means comprising a pair of photosensitive elements mounted on a common substrate, and, e. means coupled to said photodetector means for deriving an output signal proportional to the difference in amplitude between said two signals.
Claim 2
Dependent Claim
199 words
Apparatus for analyzing incident radiation comprising: a. first and second means for spatially dispersing said incident radiation to form a dispersion of radiation in a plane, said dispersion being composed of radiation zones of relatively low intensity characteristic of a particular substance when the characteristic spectra of said substance are present in the incident radiation, b. first mask means positioned in said plane and in the path of light emerging from said first dispersing means, said first mask means having a plurality of relatively opaque and transparent regions, said regions being correlative with said relatively high intensity zones of said dispersion, c. second mask means positioned in said plane and in the path of light emerging from said second dispersing means, said second mask means having a plurality of relatively opaque and transparent regions, said regions being correlative with said relatively low intensity zones of said dispersion, d. photodetector means positioned to receive light emerging from said first and second mask means, said photodetector means comprising a pair of photosensitive elements mounted on a common substrate, and, e. means coupled to said photodetector means for deriving an output signal proportional to the difference in amplitude between said two signals.
Claim 3
Dependent Claim
41 words
Apparatus as claimed in claim 1 wherein the relative widths of the opaque and transparent regions of the first and second mask means is such that the transmissivity of the first and second masks to white light is substantially the same.
Claim 4
Dependent Claim
57 words
Apparatus as claimed in claim 1 wherein said photodetector means comprises a pair of photosensitive elements mounted on a common substrate, and wherein the relative widths of the opaque and transparent regions of the first and second mask means is such that the transmissivity of the first and second masks to white light is substantially the same.
Claim 5
Dependent Claim
164 words
Apparatus for analyzing incident radiation comprising: a. means for spatially dispersing said incident radiation to form a dispersion of radiation in a plane, said dispersion being composed of radiation zones of relatively high intensity and low intensity characteristic of a particular substance when the characteristic spectra of said substance are present in the incident radiation, b. a photodetector having a substrate positioned in said plane wherein said dispersion is formed, c. said substrate having a first pattern defined by light sensitive and light insensitive regions, said regions being correlative with said relatively high intensity zones of said dispersion, said first pattern producing a first signal, d. said substrate having a second pattern defined by light sensitive and light insensitive regions, said regions being correlative with said relatively low intensity zones of said dispersion, said second pattern producing a second signal, and e. means coupled to said photodetector for deriving an output signal proportional to the difference in amplitude between said first and second signals.
Claim 6
Dependent Claim
164 words
Apparatus for analyzing incident radiation comprising: a. means for spatially dispersing said incident radiation to form a dispersion of radiation in a plane, said dispersion being composed of radiation zones of relatively high intensity and low intensity characteristic of a particular substance when the characteristic spectra of said substance are present in the incident radiation, b. a photodetector having a substrate positioned in said plane wherein said dispersion is formed, c. said substrate having a first pattern defined by light sensitive and light insensitive regions, said regions being correlative with said relatively high intensity zones of said dispersion, said first pattern producing a first signal, d. said substrate having a second pattern defined by light sensitive and light insensitive regions, said regions being correlative with said relatively low intensity zones of said dispersion, said second pattern producing a second signal, and e. means coupled to said photodetector for deriving an output signal proportional to the difference in amplitude between said first and second signals.
Claim 7
Dependent Claim
14 words
Apparatus as claimed in claim 4 wherein said first and second patterns are interdigitated.
Claim 8
Dependent Claim
42 words
Apparatus as claimed in claim 5 wherein the relative widths of the sensitive regions of said first and second patterns is such that said first and second signals are of substantially equal amplitude when said dispersing means is exposed to white light.
References Cited (Backward Citations)
US3518002A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-09-16 | 1978-03-18 | 1978-09-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-16 | 1982-03-18 | 1982-09-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-16 | 1986-03-18 | 1986-09-17 | $7700.00 | Window Closed / Lapsed |