US4240696A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multilayer electro-optically tunable filter
Assignee: Boeing North American Inc
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Filing: 1979-11-13
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Granted: 1980-12-23
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Expires: 1999-11-13
Abstract
Abstract Disclosed is an optical filter, including a plurality of adjacent layer pairs, each pair having an incident and an emergent surface and including a first dielectric layer having a thickness t and a refractive index n, a second dielectric layer, adjacent to the first layer, having a thickness t and a refractive index n, and a control electrode disposed between and in electrical contact with the layers. The filter further includes a plurality of ground electrodes disposed on the layer pairs to electrically contact each incident and emergent surface, a source of electric potential, and a switch for connecting the source between the control electrodes and the ground electrodes, whereby light having a wavelength λ=4nt will be reflected by the filter upon closing the switch and thereby applying the electric potential in opposite directions across the first and second layer pairs. The plurality of layer pairs may include m layer pairs, with the thickness of each dielectric layer in the ith pair (i=1, 2, 3 . . . m) being t i , such that nt i =λ i /4, the filter thereby being adapted to reflect light having wavelength in the range λ 1 , λ 2 , λ 3 . . . λ m .
Inventors
- 👤 John M. Tracy
- 👤 Pochi A. Yeh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 22:21
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/21; G02F1/03; G02F1/213
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
116 words
An optical filter, comprising: a plurality of adjacent layer pairs, each pair having an incident and an emergent and including: a first dielectric layer with a refractive index n, a second dielectric layer with a refractive index n adjacent to said first layer, said layers having the same thickness, and a control electrode disposed between and in electrical contact with said layers; and a plurality of ground electrodes disposed on said layer pairs such that at least one of said ground electrodes is in electrical contact with each incident and each emergent surface, whereby light traversing the filter may be controlled by the application of an electric potential between said control electrodes and said ground electrodes.
Claim 2
Dependent Claim
116 words
An optical filter, comprising: a plurality of adjacent layer pairs, each pair having an incident and an emergent and including: a first dielectric layer with a refractive index n, a second dielectric layer with a refractive index n adjacent to said first layer, said layers having the same thickness, and a control electrode disposed between and in electrical contact with said layers; and a plurality of ground electrodes disposed on said layer pairs such that at least one of said ground electrodes is in electrical contact with each incident and each emergent surface, whereby light traversing the filter may be controlled by the application of an electric potential between said control electrodes and said ground electrodes.
Claim 3
Dependent Claim
28 words
The filter of claim 1, wherein nt=λ/4 where t is the thickness of each layer, the filter thereby being adapted to selectively reflect light having a wavelength λ.
Claim 4
Dependent Claim
22 words
The filter of claim 1, wherein said control and ground electrodes comprise doped conductive layers in said first and second dielectric layers.
Claim 5
Dependent Claim
27 words
The filter of claim 1, further comprising: a source of electric potential; and a switch for connecting said source between said control electrodes and said ground electrodes.
Claim 6
Dependent Claim
35 words
The filter of claim 1, wherein said layer pairs vary from a minimum to a maximum thickness, the filter thereby being adapted to operate as a broadband reflector upon the application of said electric potential.
Claim 7
Dependent Claim
69 words
The filter of claim 5, wherein said plurality of layer pairs comprises m layer pairs, with the thickness of each dielectric layer in the ith pair (i=1, 2, 3 . . . m) being t i , such that nt.sub.i =λ.sub.i /4, the filter thereby being adapted to reflect light having wavelengths in the range λ 1 , λ 2 , λ 3 . . . λ m .
Claim 8
Dependent Claim
48 words
The filter of claim 6, further comprising: a source of electric potential; and a control switch for independently connecting said source between said ground electrodes and each of said control electrodes, said filter thereby being tunable within the range of wavelengths from λ 1 to λ m .
Claim 9
Dependent Claim
136 words
An optical filter, comprising: a plurality of adjacent layer pairs, each pair having an incident and an emergent surface and including: a first dielectric layer having a thickness t and a refractive index n, a second dielectric layer, adjacent to said first layer, having a thickness t and a refractive index n, and a control electrode disposed between and in electrical contact with said layers; and a plurality of ground electrodes disposed on said layer pairs to electrically contact each incident and emergent surface; a source of electric potential; and a switch for connecting said source between said control electrodes and said ground electrodes, whereby light having a wavelength λ=4nt will be reflected by the filter upon closing said switch and thereby applying said electric potential in opposite directions across said first and second layer pairs.
Claim 10
Dependent Claim
136 words
An optical filter, comprising: a plurality of adjacent layer pairs, each pair having an incident and an emergent surface and including: a first dielectric layer having a thickness t and a refractive index n, a second dielectric layer, adjacent to said first layer, having a thickness t and a refractive index n, and a control electrode disposed between and in electrical contact with said layers; and a plurality of ground electrodes disposed on said layer pairs to electrically contact each incident and emergent surface; a source of electric potential; and a switch for connecting said source between said control electrodes and said ground electrodes, whereby light having a wavelength λ=4nt will be reflected by the filter upon closing said switch and thereby applying said electric potential in opposite directions across said first and second layer pairs.
Claim 11
Dependent Claim
143 words
An optical filter, comprising: m adjacent layer pairs graduated in thickness, each pair having an incident and an emergent surface, the ith pair (i=1, 2, 3 . . . m) including: a first dielectric layer having a thickness t i and a refractive index n, a second dielectric layer, adjacent to said first layer, having a thickness t i and a refractive index n, and a control electrode disposed between and in electrical contact with said layers; a plurality of ground electrodes disposed on said layer pairs to electrically contact each incident and emergent surface; a source of electric potential; and switching means for independently connecting said source between each of said control electrodes and said ground electrodes, whereby light having a wavelength λ i =4nt i will be reflected by said filter when said potential is applied to said ith layer pair.
Claim 12
Dependent Claim
143 words
An optical filter, comprising: m adjacent layer pairs graduated in thickness, each pair having an incident and an emergent surface, the ith pair (i=1, 2, 3 . . . m) including: a first dielectric layer having a thickness t i and a refractive index n, a second dielectric layer, adjacent to said first layer, having a thickness t i and a refractive index n, and a control electrode disposed between and in electrical contact with said layers; a plurality of ground electrodes disposed on said layer pairs to electrically contact each incident and emergent surface; a source of electric potential; and switching means for independently connecting said source between each of said control electrodes and said ground electrodes, whereby light having a wavelength λ i =4nt i will be reflected by said filter when said potential is applied to said ith layer pair.
References Cited (Backward Citations)
US2493200A
Cited
US3427092A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-12-23 | 1984-06-23 | 1984-12-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-12-23 | 1988-06-23 | 1988-12-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-12-23 | 1992-06-23 | 1992-12-23 | $7700.00 | Window Closed / Lapsed |