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:
Nov. 30, 1999
Filed:
Apr. 18, 1997
Joel Askinazi, Trumbull, CT (US);
Authi A Narayanan, Thousand Oaks, CA (US);
Hoa T Bui, Trumbull, CT (US);
Joseph A Vigil, Oxnard, CA (US);
John J Vajo, Calabasas, CA (US);
Raytheon Company, Lexington, MA (US);
Abstract
The present invention provides a broadband transmitting protective coating (10) including an AlGaP protective layer (14) deposited on an optical substrate (12) and an anti-reflection film (16) deposited on the AlGaP protective layer (14). The coating (10) is suitable for use with typical infrared and broadband optical substrate materials such as germanium or multi-spectral ZnS. In the case of a germanium substrate (12), the anti-reflection film (16), (16a) preferably consists of a single layer of hard carbon or alternating layers of hard carbon and silicon. In the case of a multi-spectral ZnS substrate (12a), the anti-reflection film (16b) preferably consists of layered Al.sub.2 O.sub.3 /TaO.sub.5 /LaF.sub.3 /MgF.sub.2. The protective coating (10) is preferably deposited on the optical substrate (12) by a metal organic chemical vapor deposition process wherein an initial layer of AlP is nucleated on the substrate (12) at a temperature of approximately 400.degree. C. The temperature of the substrate (12) is then raised to approximately 600.degree. C. and a layer of AlGaP (14) is grown on the substrate (12) to a preselected thickness. The AlGaP coated optical substrate (12) is then polished to a desired smoothness. The anti-reflection film (16) is then deposited on the AlGaP layer (14) using an RF chemical vapor deposition process or a thermal evaporation process.