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:
Jul. 13, 2004
Filed:
Dec. 11, 2002
Hisatoshi Otsuka, Niigata-ken, JP;
Kazuo Shirota, Niigata-ken, JP;
Akira Fujinoki, Koriyama, JP;
Hiroyuki Nishimura, Koriyama, JP;
Takayuki Shimakawa, Koriyama, JP;
Other;
Abstract
A cylindrical, chlorine-free synthetic quartz glass blank of a specific size obtained by homogenizing a synthetic quartz glass ingot having periodic striae along a direction of growth has (a) striae grades in the working and off-axis directions which meet grade A of U.S. military specification MIL-G-174B, (b) average hydroxyl group concentrations in the working and off-axis directions of 700 to 1,000 ppm each, (c) average fictive temperatures in the working and off-axis directions of 850 to 950° C. each, and (d) a refractive index distribution for 633 nm wavelength light in the working direction of at most 1×10 . The blank has a good transmittance to laser light, undergoes little deterioration when irradiated with laser light, and is particularly suitable for ArF excimer laser-related applications.