The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 28, 1991
Filed:
Apr. 07, 1988
Wenpeng Chen, Bethesda, MD (US);
Martin Marietta Corporation, Bethesda, MD (US);
Abstract
An optical power limiter and switch, transparent at low light intensity and opaque at high intensity, is comprised of a pair of right triangular prisms separated by a liquid film whose refractive index changes in response to optical energy. A first or input lens focuses the light upon the liquid film at an angle less than the critical angle of total reflection of the prism-liquid interface and a second or output lens refocuses the energy to a detector through an aperture. When the intensity of the optical energy reaches a first predetermined level, the optical energy is defocused and diverted from the detector. When the intensity of the optical energy reaches a second predetermined higher level, the critical angle is achieved whereupon the optical energy is reflected away from the interface rather than through it. The liquid material of the film also includes an optically absorbent dye for attenuating optical energy of predetermined wavelengths transmitted through the film prior to defocusing and total reflection.