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:
Nov. 15, 1988
Filed:
Feb. 20, 1987
Yasuaki Nakane, Tokyo, JP;
Kazumine Ito, Tokyo, JP;
Sanae Abe, Chiba, JP;
Takashi Naito, Kanagawa, JP;
Sony Corporation, Tokyo, JP;
Abstract
An optical recording disc in which a disc substrate made of a synthetic resin having a light transmittance and a hub made of a synthetic resin, fixed to a center part of the disc substrate by means of a predetermined technique such as a supersonic wave expansion molding and on which a circular magnetic metal plate is installed by means of an insert molding and so on are provided and a circular groove which is continuous at an outer peripheral side of a fixing part between the disc substrate and hub is furthermore installed on at least either of the disc substrate or hub. The groove is provided for absorbing a stress generated due to a difference in thermal expansion rates between the disc substrate made of the snythetic resin and magnetic metal plate.