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. 07, 2020
Filed:
Jun. 11, 2015
Applicant:
Shin-etsu Chemical Co., Ltd., Tokyo, JP;
Inventors:
Daijitsu Harada, Joetsu, JP;
Kazuo Shirota, Joetsu, JP;
Hisashi Yagi, Joetsu, JP;
Masaki Takeuchi, Joetsu, JP;
Assignee:
SHIN-ETSU CHEMICAL CO., LTD., Tokyo, JP;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C03C 17/00 (2006.01); C03C 19/00 (2006.01); G01N 21/23 (2006.01); B28D 1/00 (2006.01); G01N 21/958 (2006.01); B07C 5/342 (2006.01);
U.S. Cl.
CPC ...
C03C 17/00 (2013.01); B28D 1/00 (2013.01); C03C 19/00 (2013.01); G01N 21/23 (2013.01); B07C 5/342 (2013.01); G01N 21/958 (2013.01);
Abstract
A synthetic quartz glass substrate is prepared by furnishing a synthetic quartz glass block, coating an arbitrary surface and an opposite surface of the block with a liquid having a transmittance of at least 99.0%/mm at the wavelength of birefringence measurement, measuring the birefringence of the block by letting light enter one coated surface and exit the other coated surface, and sorting the block to an acceptable or unacceptable group, based on the measured birefringence value.