Optical: systems and elements – Glare or unwanted light reduction
Reexamination Certificate
1984-05-03
2001-12-11
Moskowitz, Nelson (Department: 3662)
Optical: systems and elements
Glare or unwanted light reduction
C359S490020, C359S506000, C359S506000
Reexamination Certificate
active
06328449
ABSTRACT:
The invention described herein may be manufactured, used, and licensed by the U.S. Government for governmental purposes without the payment of any royalties thereon.
BACKGROUND OF THE INVENTION
This invention is in the field of spectral filters, and is particularly concerned with the infrared spectrum. Such filters include three basic types: (1) absorption, using the light-absorbing properties of matter, (2) Fabry-Perot, which take advantage of the electromagnetic wave interference phenornona, and (3) birefringent, utilizing acousto-optical and electro-optical properties of materials. These filters can be designed to transmit, absorb, and reflect (and combinations of these) particular spectral bands or wavelengths. Although the filters can be theoretically designed to absorb or reflect 100% of particular wavelengths or bands of radiation, their absorption or reflectance in practice is less than 100%. Normally this is not important, unless one is using such a filter to protect a sensitive infrared detector from high-intensity radiation. In this case, 100% radiation blockage (absorption) or diversion (reflection) may be required. The instant invention is able to provide 100% elimination of the unwanted radiation of a particular wavelength from a thermally radiative scene.
SUMMARY OF THE INVENTION
This invention is an optical system which acts as a dispersion filter; the system consists of a quarter-wave birefringent polarizer and a dielectric dispersive mirror on an optical path. The polarizer is designed for some particular wavelength of interest in a spectrum, and the mirror is inclined to the optical path such that the Brewster angle for the particular wavelength is in the plane of incidence. The radiation of the particular wavelength is transmitted by the mirror, and the other wavelengths are reflected by the mirror. The reflected wavelengths are directed to a photodetector or to other optical devices.
REFERENCES:
patent: 2726173 (1955-12-01), Martin
patent: 3439968 (1969-04-01), Hansen et al.
patent: 3765746 (1973-10-01), Ashley et al.
patent: 3792916 (1974-02-01), Sarna
patent: 3934210 (1976-01-01), Yarborough et al.
patent: 3969573 (1976-07-01), Barrhuise et al.
patent: 4184767 (1980-01-01), Hughes et al.
patent: 4311384 (1982-01-01), Keene
patent: 4403190 (1983-09-01), Greenwood
patent: 4406520 (1983-09-01), Sato
patent: 4504123 (1985-03-01), Smith
patent: 4530600 (1985-07-01), Lopez
patent: 4545651 (1985-10-01), Kato et al.
patent: 2725107 (1978-12-01), None
patent: 0963348 (1950-07-01), None
patent: 0319869 (1929-10-01), None
Partington, “An Advanced Treatise on Physical Chemistry”, 1953, pp 104-107, vol. 4, Langmans, Greene & Co., N.Y.*
Brewster, “Treatise on Optics”,1853, pp 220-223, Published in London England by Langman et al.*
Makas et al, “New Arrangement of . . . Lufrared,” pp 998-9, Opt. Soc. Am., vol. 45, 1955.*
Bagomalov et al, “An Infrared Radiation Polarizer,” 6/73, pp 982, Instrum. Exp. Tech (USA), vol. 16, #3, Pt 2.*
Driscoll et al, “Handbook of Optics”, 1978, pp 7-13, Opt. Soc. of America, McGraw-Hill Book Co.*
Sears, “Optics”, 1949, pp 174-177, Addison-Wesley Pub., Co., Inc.*
Vinograpova, “Multicomponent Dispersive . . . Filters”, 8/70, Opt. & Spectrosc., vol. 29, #2, pp 209-11, 350/311.*
Jenkins et al, “Fundamentals of Optics”, 1976, pp 498-499, 524, 525, McGraw-Hill Book Co.
Dunn Aubrey J.
Lane Anthony T.
Lee Milton W.
Moskowitz Nelson
The United States of America as represented by the Secretary of
LandOfFree
Brewster-angle dispersion filter (U) does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Brewster-angle dispersion filter (U), we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Brewster-angle dispersion filter (U) will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2569159