US4269481A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multiple-cavity electro-optic tunable filter
Assignee: Boeing North American Inc
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Filing: 1979-07-06
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Granted: 1981-05-26
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Expires: 1999-07-06
Abstract
Abstract A multiple cavity electro-optic tunable filter includes an ordered row of n electro-optically tunable plates (n=2, 3, 4 . . . ), each plate having an incident surface and an emergent surface, an incident reflective coating on the incident surface of the first tunable plate in the row, an emergent reflective coating on the emergent surface of the nth tunable plate in the row, and a series of (n-1) absorbent films, one of the films being disposed between each pair of adjacent plates in the row in mating contact with the adjacent surfaces of the adjacent plates.
Inventors
- 👤 Pochi A. Yeh
- 👤 John M. Tracy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 23:58
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/21; G02F1/03; G02F1/213
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
98 words
A multiple cavity electro-optic tunable filter, comprising: an ordered row of n electro-optically tunable plates (n=2, 3, 4, . . . ), each plate including an incident surface and an emergent surface; an incident reflective coating on the incident surface of the first tunable plate in said row; an emergent reflective coating on the emergent surface of the nth tunable plate in said row; and a series of (n-1) absorbent metallic films, one of said films being disposed between each pair of adjacent plates in said row in mating contact with the adjacent surfaces of said adjacent plates.
Claim 2
Dependent Claim
98 words
A multiple cavity electro-optic tunable filter, comprising: an ordered row of n electro-optically tunable plates (n=2, 3, 4, . . . ), each plate including an incident surface and an emergent surface; an incident reflective coating on the incident surface of the first tunable plate in said row; an emergent reflective coating on the emergent surface of the nth tunable plate in said row; and a series of (n-1) absorbent metallic films, one of said films being disposed between each pair of adjacent plates in said row in mating contact with the adjacent surfaces of said adjacent plates.
Claim 3
Dependent Claim
15 words
The filter of claim 1, wherein said incident and emergent reflective coatings are electrically conductive.
Claim 4
Dependent Claim
22 words
The filter of claim 2, wherein each of said reflective coatings further comprises: a stacked dielectric mirror; and an electrically conductive layer.
Claim 5
Dependent Claim
14 words
The filter of claim 3, wherein said electrically conductive layer comprises a metallic electrode.
Claim 6
Dependent Claim
14 words
The filter of claim 3, wherein said electrically conductive layer comprises a transparent semiconductor.
Claim 7
Dependent Claim
16 words
The filter of claim 1, wherein each of said metallic films is approximately 200 A thick.
Claim 8
Dependent Claim
12 words
The filter of claim 6, wherein said metallic films comprise silver films.
Claim 9
Dependent Claim
14 words
The filter of claim 1, wherein each of said plates comprises an electro-optic crystal.
Claim 10
Dependent Claim
36 words
The filter of claim 8, wherein each of said crystals further comprises a Z-cut electro-optic crystal having a point group selected from the group consisting of 4, 4 mm, 3, 3 m, 6, and 6 mm.
Claim 11
Dependent Claim
15 words
The filter of claim 9, wherein each of said crystals comprises a LiNbO 3 crystal.
Claim 12
Dependent Claim
33 words
The filter of claim 1, wherein said ordered row comprises two electro-optically tunable plates of different thicknesses, the difference in thickness being large enough to suppress spectral side lobes transmitted by the filter.
Claim 13
Dependent Claim
42 words
The filter of claim 1, wherein said ordered row comprises two electro-optically tunable plates having thicknesses in the ratio 1:(1-G -1 ), where the value of G is chosen to increase the filter free spectral tuning range while maintaining sufficient off-bandd rejection.
Claim 14
Dependent Claim
14 words
The filter of claim 1, wherein said ordered row comprises four electro-optically tunable plates.
Claim 15
Dependent Claim
44 words
The filter of claim 13, wherein said plates have thicknesses in the ratio 1:(1-G -1 ):(1-G -2 ):(1-G -1 )(1-G -2 ), where the value of G is chosen to increase the free spectral tuning range of the filter while maintaining sufficient off-band rejection.
Claim 16
Dependent Claim
14 words
The filter of claim 13, wherein said plates have thicknesses in the ratio 1:2:4:8.
Claim 17
Dependent Claim
14 words
The filter of claim 1, wherein said ordered row comprises eight electro-optically tunable plates.
Claim 18
Dependent Claim
58 words
The filter of claim 12, wherein said plates have thicknesses in the ratio 1:(1-G -1 ):(1-G -2 ):(1-G -1 )(1-G 2 ):(1-G -4 ):(1-G.sup.-1)(1-G -4 ):(1-G -2 )(1-G -4 ):(1-G -1 )(1-G -2 )(1-G - 4), where the value of G is chosen to increase the free spectral tuning range of the filter while maintaining sufficient off-band rejection.
Claim 19
Dependent Claim
84 words
A two-cavity electro-optic tunable filter, comprising: a first electro-optically tunable plate, including a first incident surface and a first emergent surface; a second electro-optically tunable plate parallel to said first plate, including a second incident surface and a second emergent surface; an incident reflective coating on said first incident surface; an emergent reflective coating on said second emergent surface; and an absorbent film disposed between said first and second plates and in mating contact with said first emergent surface and said second incident surface.
Claim 20
Dependent Claim
84 words
A two-cavity electro-optic tunable filter, comprising: a first electro-optically tunable plate, including a first incident surface and a first emergent surface; a second electro-optically tunable plate parallel to said first plate, including a second incident surface and a second emergent surface; an incident reflective coating on said first incident surface; an emergent reflective coating on said second emergent surface; and an absorbent film disposed between said first and second plates and in mating contact with said first emergent surface and said second incident surface.
Claim 21
Dependent Claim
119 words
A two-cavity electro-optic tunable filter, comprising: a first electro-optically tunable crystal of a thickness l 1 , having a first incident surface and a first emergent surface; an incident reflecting electrode on said first incident surface; a second electro-optically tunable crystal of a thickness l 2 , having a second incident surface and a second emergent surface; an emergent reflecting electrode on said second emergent surface; and an absorbent metallic film disposed between said first and second crystals and in contact with said first emergent surface and said second incident surface, such that l 2 =(1-G -1 )l 1 , where G is chosen to increase the free spectral tuning range of the filter while maintaining sufficient off-band rejection.
Claim 22
Dependent Claim
119 words
A two-cavity electro-optic tunable filter, comprising: a first electro-optically tunable crystal of a thickness l 1 , having a first incident surface and a first emergent surface; an incident reflecting electrode on said first incident surface; a second electro-optically tunable crystal of a thickness l 2 , having a second incident surface and a second emergent surface; an emergent reflecting electrode on said second emergent surface; and an absorbent metallic film disposed between said first and second crystals and in contact with said first emergent surface and said second incident surface, such that l 2 =(1-G -1 )l 1 , where G is chosen to increase the free spectral tuning range of the filter while maintaining sufficient off-band rejection.
References Cited (Backward Citations)
US3572898A
Cited
US3644017A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-05-25 | 1984-11-24 | 1985-05-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-05-25 | 1988-11-24 | 1989-05-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-05-25 | 1992-11-24 | 1993-05-26 | $7700.00 | Window Closed / Lapsed |