US4400058A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tunable Fabry-Perot filter
Assignee: Honeywell Inc
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Filing: 1982-06-04
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Granted: 1983-08-23
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Expires: 2002-06-04
Abstract
Abstract A tunable Fabry-Perot filter for transmitting light in the wavelength range from 3-40 microns is disclosed wherein a pair of low index substrates of refractive index less than 2.4 and positioned between an adjustable spacer means have, on their facing sides, a non-metallic coating of refractive index of at least 4.0 and of optical thickness less than one-half the minimum wavelength to be transmitted. Preferred substrates are potassium halides, cesium halides, and zinc selenide, and preferred high index coatings are from the group of lead telluride, bismuth telluride, germanium telluride and germanium.
Inventors
- 👤 William W. Durand
- 👤 Ronald E. Peterson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 16:55
CPC Classifications
G; G01; G01J; G01J3/00; G01J3/12; G01J3/26
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
99 words
A tunable Fabry-Perot filter device, comprising: a pair of low index substrates having a refractive index of less than 2.4 and mounted in parallel relationship so as to present facing sides to each other in an optical path; a high index, non-metallic coating having a refractive index of at least 4.0 and an optical thickness less than one half of the minimum wavelength to be transmitted, said high index coating being on said facing sides of each said low index substrates; and spacer means for mounting said low index substrates and for adjusting the distance between said facing sides.
Claim 2
Dependent Claim
99 words
A tunable Fabry-Perot filter device, comprising: a pair of low index substrates having a refractive index of less than 2.4 and mounted in parallel relationship so as to present facing sides to each other in an optical path; a high index, non-metallic coating having a refractive index of at least 4.0 and an optical thickness less than one half of the minimum wavelength to be transmitted, said high index coating being on said facing sides of each said low index substrates; and spacer means for mounting said low index substrates and for adjusting the distance between said facing sides.
Claim 3
Dependent Claim
28 words
The device of claim 1, wherein said low index substrate is selected from the group of low index materials consisting of potassium halide, cesium halide and zinc selenide.
Claim 4
Dependent Claim
12 words
The device of claim 2, wherein said potassium halide is potassium chloride.
Claim 5
Dependent Claim
26 words
The device of claim 1, wherein said high index non-metallic coating is selected from the group consisting of lead telluride, bismuth telluride, germanium telluride and germanium.
Claim 6
Dependent Claim
32 words
The device of claim 1 wherein said spacer means is adapted to vary the distance between said facing sides to pass light of a wavelength ranging from 3 microns to 40 microns.
Claim 7
Dependent Claim
109 words
A pair of low index substrates having a refractive index of less than 2.4 and mounted in parallel relationship so as to present facing sides to each other in an optical path; a high index non-metallic coating which is less than ten percent absorbing in the 3 to 40 micron wavelength range and has a refractive index of at least 4.0 and an optical thickness less than one half of the minimum wavelength to be transmitted, said high index coating being on said facing sides of each said low index substrates; and spacer means for mounting said low index substrates and for adjusting the distance between said facing sides.
Claim 8
Dependent Claim
109 words
A pair of low index substrates having a refractive index of less than 2.4 and mounted in parallel relationship so as to present facing sides to each other in an optical path; a high index non-metallic coating which is less than ten percent absorbing in the 3 to 40 micron wavelength range and has a refractive index of at least 4.0 and an optical thickness less than one half of the minimum wavelength to be transmitted, said high index coating being on said facing sides of each said low index substrates; and spacer means for mounting said low index substrates and for adjusting the distance between said facing sides.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-08-22 | 1987-02-21 | 1987-08-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-08-22 | 1991-02-21 | 1991-08-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-08-22 | 1995-02-21 | 1995-08-23 | $7700.00 | Window Closed / Lapsed |