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:
Jan. 24, 2006
Filed:
Feb. 26, 2002
Applicant:
Tetsuo Kuwabara, Ibaraki-ken, JP;
Inventor:
Tetsuo Kuwabara, Ibaraki-ken, JP;
Assignee:
Canon Kabushiki Kaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C30B 11/00 (2006.01); C30B 29/12 (2006.01);
U.S. Cl.
CPC ...
Abstract
A calcium fluoride crystal produced in accordance with a method for producing calcium fluoride crystal on the basis of refining a raw material of calcium fluoride and causing crystal growth of the refined calcium fluoride, the method including a process of raising a purity of the calcium fluoride to complement the refining, wherein a transition density in crystal is not greater than 1×10/cm, and that dispersion of transition density inside an effective portion in crystal is in a range of ±5×10/cm. Also disclosed is an optical element to be manufactured by use of such CaF2 crystal.