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:
Jan. 15, 1991
Filed:
Jan. 09, 1990
Applicant:
Inventors:
Toshinori Morizane, Nerima-ku, Tokyo, JP;
Tadao Tokushima, Hamamatsu-shi, Shizuoka-ken, JP;
Assignee:
Other;
Primary Examiner:
Int. Cl.
CPC ...
B44C / ; C03C / ; C03C / ; B32B / ;
U.S. Cl.
CPC ...
428410 ; 156628 ; 156645 ; 156654 ; 156663 ; 65 31 ; 252 792 ; 360135 ; 427129 ; 428156 ;
Abstract
Herein disclosed is a method for manufacturing a base plate for a recording disc, which comprises steps of: subjecting a base plate containing therein SiO.sub.2 -Li.sub.2 O-Al.sub.2 O.sub.3 series crystallized glass to crystallizing treatment; then polishing the surface of said base plate; and thereafter subjecting the base plate to etching treatment with use of etching agents having different rates of etching between the crystallized layer and the amorphous layer, and also a base plate for a recording disc which is produced by the method as described above.