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:
Aug. 17, 1993
Filed:
Oct. 30, 1992
Applicant:
Inventors:
Satoru Miyashita, Nagano, JP;
Sadao Kanbe, Nagano, JP;
Motoyuki Toki, Nagano, JP;
Tetsuhiko Takeuchi, Nagano, JP;
Hirohito Kitabayashi, Nagano, JP;
Assignee:
Seiko Epson Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C03B / ;
U.S. Cl.
CPC ...
65 17 ; 65-311 ; 65 181 ; 65 24 ; 65 26 ; 65111 ; 65136 ; 6537413 ; 6537415 ; 65901 ; 264 66 ; 501 12 ;
Abstract
A method for preparing a silica glass article of improved purity is provided. The article is prepared by a sol-gel method and is then heat treated to a selected temperature between about 1500.degree. and 2200.degree. C. and maintained at the selected temperature for a predetermined period of time sufficient to remove silica crystals, inclusions, microcracks and bubbles. The resulting silica glass articles have improved purity and can be used as photomask substrates or as preforms for optical fibers.