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. 12, 1999
Filed:
Feb. 28, 1994
Kenji Takahashi, Miyagi, JP;
Katsuaki Tsurushima, Kanagawa, JP;
Tadao Yoshida, Kanagawa, JP;
Kazuhiko Fujiie, Tokyo, JP;
Hirotoshi Fujisawa, Tokyo, JP;
Hiroshi Mukawa, Tokyo, JP;
Sony Corporation, Tokyo, JP;
Abstract
An optical disc includes a disc base plate of a light-transmitting synthetic material having a recess for mounting a magnetic plate, and a holding part, integral with the disc base plate, for loosely holding the magnetic plate mounted in the recess with respect to the disc base plate. It is possible with the present optical disc to prevent distortion of the disc base plate otherwise caused by the difference in thermal expansion coefficients of the two components to inhibit double refraction of the disc base plate otherwise caused by such distortion to maintain good recording/reproducing characteristics.