Patent US4794398A successfully refreshed from Google Patents.
US4794398A
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Multimode, multispectral scanning and detection
Assignee: Norden Systems Inc
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Filing: 1986-10-01
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Granted: 1988-12-27
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Expires: 2006-10-01
Abstract
Abstract In a multimode or multispectral electromagnetic detection system (11), a pair of rotatable scanning prisms (13' and 13"), each of said prisms comprising at least a pair of cooperative subprisms (13'a, 13'b, 13"a and 13"b), and the cooperative materials of the subprism being selected so as to ensure that electromagnetic radiation passing through the pair of rotatable prisms is equally deviated in a transverse direction.
Inventors
- 👤 Peter E. Raber
- 👤 Lester H. Kosowsky
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 19:03
CPC Classifications
H; H01; H01Q; H01Q3/00; H01Q3/12; H01Q3/14
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
125 words
A multi frequency electromagnetic detection system comprising: electromagnetic transceiver means responsive to electromagnetic radiation in a radar frequency range about a frequency f1 and an optical frequency range about a frequency f2; and scanning means including cooperative first and second rotatable scanning prisms, characterized in that each of said scanning prisms comprises at least first and second subprisms each constructed of a material, having frequency-dependent indices of refraction na(f) and nb(f), respectively and having prism angles aa and ab, respectively, with the indices of refraction related by the condition that na(f1)=nb(f1) and the condition that na(f2)<nb(f2)<na(f1), and the prism angles having values such that the deviation of electromagnetic radiation passing through said scanning means is the same for frequencies substantially equal to f1 or f2.
Claim 2
Dependent Claim
125 words
A multi frequency electromagnetic detection system comprising: electromagnetic transceiver means responsive to electromagnetic radiation in a radar frequency range about a frequency f1 and an optical frequency range about a frequency f2; and scanning means including cooperative first and second rotatable scanning prisms, characterized in that each of said scanning prisms comprises at least first and second subprisms each constructed of a material, having frequency-dependent indices of refraction na(f) and nb(f), respectively and having prism angles aa and ab, respectively, with the indices of refraction related by the condition that na(f1)=nb(f1) and the condition that na(f2)<nb(f2)<na(f1), and the prism angles having values such that the deviation of electromagnetic radiation passing through said scanning means is the same for frequencies substantially equal to f1 or f2.
Claim 3
Dependent Claim
58 words
A system according to claim 1 for deviating electromagnetic radiation through an angle d for each scanning prism, further characterized in that d is determined by the equation: d=sin.sup.-1 {nb(f)sin[ab-sin.sup.-1 {[na(f)/nb(f)]sin(aa+sin.sup.-1) {sin(ab-aa)/na(f)})}]}, where ab is the angle of the prism having index of refraction nb and aa is the angle of the prism having index of refraction na.
Claim 4
Dependent Claim
16 words
The arrangement of claim 2, in which at least one of the frequencies scanned is infrared.
Claim 5
Dependent Claim
17 words
The arrangement of claim 2, in which at least one of the frequencies used is radio frequency.
Claim 6
Dependent Claim
15 words
The arrangement of claim 2, in which at least one of said frequencies is visible.
References Cited (Backward Citations)
US2887684A
Cited
US3255451A
Cited
US3255453A
Cited
US3979755A
Cited
US4194209A
Cited
US4480254A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-12-27 | 1992-06-27 | 1992-12-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-12-27 | 1996-06-27 | 1996-12-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-12-27 | 2000-06-27 | 2000-12-27 | $7700.00 | Window Closed / Lapsed |