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:
Sep. 12, 1995
Filed:
Dec. 10, 1993
Erik J Bjornard, Northfield, MN (US);
Debra M Steffenhagen, Faribault, MN (US);
Eric R Dickey, Beaverton, OR (US);
Viratec Thin Films, Inc., Faribault, MN (US);
Abstract
An antireflection coating for a substrate including four layers and having optimized photopic reflectance and optimized for deposition by sputtering. The first layer (the layer farthest from the substrate) has a refractive index less than the refractive index of the substrate and a thickness of about one-quarter wavelength. The second layer (the layer adjacent the first layer) has an refractive index greater than about 2.2 and a thickness of about a half wavelength. The third layer has refractive index less than that of the second layer. The fourth layer (the layer adjacent the substrate) has a refractive index less than about 2.0 and greater than that of the third layer. The combined thickness of the third and fourth layers is less than about a quarter wavelength. The first and third layers may include silicon dioxide. The second layer may include titanium dioxide or niobium oxide. The fourth layer may include indium oxide, tin oxide, indium tin oxide, or zinc oxide.