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:
Sep. 19, 2000
Filed:
Dec. 29, 1997
Koji Takahashi, Yamanashi, JP;
Kazuhiko Maeda, Yamanashi, JP;
Shinji Eda, Narasaki, JP;
Jun Ozawa, Kofu, JP;
Katsutoshi Ono, Yamanashi, JP;
Kinobu Osakabe, Akishima, JP;
Nobuyuki Eto, Yamanashi, JP;
Hoya Corporation, Tokyo, JP;
Abstract
An object of the present invention is to prevent the dhesion of particles such as fine iron powders onto a glass substrate upon the production of a glass substrate for an information recording medium. To attain the above object, any one of the following means is adopted: (1) at least one of the production, inspection, packing and filling steps of the glass substrate for an information recording medium is carried out under a clean atmosphere which does not permit the adhesion of particles; (2) at least a wall surface of a chemical reinforcement tank containing a chemical reinforcement liquid therein and/or said retaining means which is contact with the chemical reinforcement liquid is formed of a stainless alloy having corrosion resistance in a high-temperature region as high as the heating temperature of the chemical reinforcement liquid; (3) a means for trapping fine particles existing in the chemical reinforcement liquid used in the chemical reinforcement step is provided; and (4) the glass substrate is washed with hydrochloric acid.