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:
May. 10, 2016
Filed:
Apr. 27, 2012
Hideki Isono, Kofu, JP;
Hidekazu Tanino, Akishima, JP;
Akira Murakami, Akiruno, JP;
Takashi Sato, Inagi, JP;
Masamune Sato, Kodaira, JP;
Masaru Onishi, Kufu, JP;
Hideki Isono, Kofu, JP;
Hidekazu Tanino, Akishima, JP;
Akira Murakami, Akiruno, JP;
Takashi Sato, Inagi, JP;
Masamune Sato, Kodaira, JP;
Masaru Onishi, Kufu, JP;
HOYA CORPORATION, Tokyo, JP;
Abstract
A method for manufacturing a glass substrate for magnetic disk is provided in which a glass is kept from being fused to a mold during press forming and shape processing to achieve a good circularity is efficiently performed. The method includes: a forming process of forming a disk-shaped glass blank by direct-pressing a molten glass by a pair of dies; and a shape processing process of performing at least one of inner hole formation and outer shape formation for forming a disk-shaped glass substrate by forming a cutting line on the principal face of the glass blank, followed by growing the cutting line to perform cutting. In the forming process, press forming is performed while the temperature of the pair of dies, over a period of time until a molten glass is separated from the die after coming into contact with the die, is set at a temperature lower than a glass transition point (Tg) and a mold release material is not attached to the surfaces of the pair of dies.