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. 01, 2003
Filed:
Dec. 14, 2000
Kazuaki Takagi, Osaka, JP;
Kunio Hibino, Osaka, JP;
Tomokazu Tokunaga, Hyogo, JP;
Fujio Okuyama, Yamagata, JP;
Minoru Onoda, Osaka, JP;
Matsushita Electric Industrial Co., Ltd., Kadoma, JP;
Abstract
A glass material ( ) is placed in a forming die including a pair of upper and lower dies ( ) and a control member ( ) for controlling the space between the upper and the lower die, and then heated, softened, and molded by pressure into a glass substrate in the shape of a parallel plate. The amount of thermal contraction of the control member is smaller than that of the glass material. Therefore, the glass substrate is released from the die when cooled after molding. The present invention can provide a glass substrate that is excellent in smoothness and form accuracy of the surface, and that is suitable for recording media such as magnetic disks that are inexpensive and suitable for mass production.