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:
Oct. 26, 2004
Filed:
Jun. 19, 2003
Yusuke Taki, Yokohama, JP;
Nikon Corporation, Tokyo, JP;
Abstract
An optical element of the present invention comprises a fluorite substrate , and a lanthanum fluoride film formed directly on the substrate . The substrate on which the lanthanum fluoride film is formed, has a plane which is a (111) plane or a plane inclined by an angle within ±30 degrees, preferably within 15 degrees from the (111) plane. Therefore, the lanthanum fluoride film undergoes the crystal growth subjected to the C-axis orientation on the optical substrate. Since the lanthanum fluoride film is dense and has a small surface area, it scarcely involves the oxidation and hydroxylation areas as well as the structural defect. Therefore, it is possible to reduce the optical loss of the optical element in the vacuum ultraviolet region.