US5452121A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable spectral resolution agile filter
Assignee: Grumman Corp
•
Filing: 1993-11-12
•
Granted: 1995-09-19
•
Expires: 2013-11-12
Abstract
Abstract A variable spectral resolution agile filter has instantly adjustable spectral resolution with no required mechanical motion and a quickly adjustable center wavelength. Adjustment of the center wavelength is accomplished by reliable piezoelectric actuators. Adjustment of the spectral resolution is achieved by changing the finesse of the system, the finesse being governed by the reflectivity of the faces. By making one of the faces exhibit electrically variable reflectivity, the finesse of the system is instantly changeable, and thus the spectral resolution is also instantly changeable.
Inventors
- 👤 Theodore W. Hilgeman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 01:33
CPC Classifications
G; G01; G01J; G01J3/00; G01J3/12; G01J3/26; G02; G02F; G02F1/00; G02F1/01; G02F1/0147; G02F1/19; G02F1/21; G02F1/213
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
63 words
In a variable spectral resolution agile filter, comprising: a pair of windows at least partially transparent to electromagnetic radiation; and tuning means for adjusting an optical path length between said windows to thereby change a center wavelength of the filter, the improvement wherein: said filter includes finesse varying means for varying a finesse of the filter in order to vary its spectral resolution.
Claim 2
Dependent Claim
63 words
In a variable spectral resolution agile filter, comprising: a pair of windows at least partially transparent to electromagnetic radiation; and tuning means for adjusting an optical path length between said windows to thereby change a center wavelength of the filter, the improvement wherein: said filter includes finesse varying means for varying a finesse of the filter in order to vary its spectral resolution.
Claim 3
Dependent Claim
65 words
A filter as claimed in claim 1, wherein said finesse varying means comprises a partially reflecting coating on one of said windows; an electrically variable reflectance material on a surface of the other of said windows which faces said partially reflecting coating; and means for electrically controlling the reflectance of said electrically variable reflectance material in order to vary the spectral resolution of said filter.
Claim 4
Dependent Claim
26 words
A filter as claimed in claim 2, wherein said tuning means comprises a piezoelectric actuator, and means for controlling an electric voltage applied to said actuator.
Claim 5
Dependent Claim
16 words
A filter as claimed in claim 2, wherein said electrically variable reflectance material is vanadium oxide.
Claim 6
Dependent Claim
23 words
A filter as claimed in claim 2, further comprising anti-reflection coatings on surfaces of said windows opposite to said first and second surfaces.
References Cited (Backward Citations)
US4553816A
Cited
US4790634A
Cited
US4923273A
Cited
US4994791A
Cited
US4999013A
Cited
US4998017A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-09-18 | 1999-03-20 | 1999-09-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-09-18 | 2003-03-20 | 2003-09-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-09-18 | 2007-03-20 | 2007-09-19 | $7700.00 | Window Closed / Lapsed |