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:
Feb. 13, 2007
Filed:
Jul. 31, 1990
Byong H. Ahn, Springfield, VA (US);
Byong H. Ahn, Springfield, VA (US);
The United States of America as represented by the Secretary of the Army, Washington, DC (US);
Abstract
Two embodiments of a multilayered low energy optical power limiter device are disclosed which protect thermal sensors against laser threats in the far infrared spectral region. One limiter device has multiple layers in order from the incoming radiation side an antireflective coating layer, a window substrate layer, a layer of chalcogenide, a germanium substrate layer, a layer of vanadium dioxide (VO), a window substrate, and an antireflective coating layer. As incoming radiation energy increases, the VOlayer will heat up and change from an unswitched transmissive state to a switched reflective state. The excessive energy past the switched state is reflected back through the germanium and chalcogenide layer and is absorbed quickly therein so that these layers also heat up quickly and are switched almost simultaneously with the VOlayer to provide high optical density at a low switching threshold temperature with high damage threshold. The second embodiment further adds a second VOlayer between the input antireflective coating layer and window substrate layers to reflect high radiation energy immediately.