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:
Apr. 15, 1997
Filed:
Dec. 14, 1994
Jun Yokoyama, Tokyo, JP;
Masaaki Miyake, Shizuoka, JP;
NEC Corporation, , JP;
Vacuum Optics Corporation, , JP;
Abstract
A beam splitter is an optical multilayer film obtained by sequentially stacking first to fifth layers respectively having refractive indexes of n.sub.1 to n.sub.5 and geometrical thicknesses d.sub.1 and d .sub.5 on a substrate having a refractive index n.sub.G. The refractive indexes of the substrate and the first to fifth layers satisfy any one of a relationship of n.sub.G =1.45 to 1.60, n.sub.1 =2.02 to 2.20, n.sub.2 =2.25 to 2.38, n.sub.3 =1.44 to 1.47, n.sub.4 =2.25 to 2.38, and n.sub.5 =1.44 to 1.47, a relationship of n.sub.G =1.45 to 1.60, n.sub.1 =1.44 to 1.47, n.sub.2 =2.25 to 2.38, n.sub.3 =1.44 to 1.47, n.sub.4 =2.25 to 2.38, and n.sub.5 =2.02 to 2.20, and a relationship of n.sub.G =1.45 to 1.60, n.sub.1 =1.44 to 1.47, n.sub.2 =2.25 to 2.38, n.sub.3 =2.02 to 2.20, n.sub.4 =2.25 to 2.38, and n.sub.5 =1.44 to 1.47, and a geometrical thickness d.sub.i of an ith layer of the first to fifth layers satisfies relation n.sub.i d.sub.i cos (.theta..sub.i)=.lambda./4, where n.sub.i is a refractive index of the ith layer, .theta..sub.i is an angle of refraction in the ith layer, and .lambda. is a center wavelength of an incident light beam to the multilayer film with an angle of incidence of 40.degree. to 50.degree..