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. 09, 1997
Filed:
Jul. 21, 1994
Applicant:
Inventor:
Tetsuro Izumitani, Hino-Shi, Tokyo, JP;
Assignee:
Other;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C03B / ;
U.S. Cl.
CPC ...
65 66 ; 65 213 ; 65 37 ; 65 65 ; 4285428 ;
Abstract
Optical glass of cubic, spherical or polygonal shape is fire polished on a graphite or Cr.sub.2 O.sub.3, concave surface with a surface roughness of 100 Angstroms or less. The optical glass having a surface roughness of 400 Angstroms or less is placed on the concave surface and fire polished by heating the optical glass between the yield point and softening point of the glass in a reducing atmosphere if the concave surface is made of graphite. A Cr.sub.2 O.sub.3 concave surface is required for Pb.sup.+2 containing glasses. The molded preform obtained has a surface roughness of 100 Angstroms or less.