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, 1993
Filed:
Dec. 21, 1990
Yumiko Anzai, Tachikawa, JP;
Yoshinori Miyamura, Nishitama, JP;
Toshio Niihara, Sayama, JP;
Harukazu Miyamoto, Hachioji, JP;
Norio Ohta, Kitasoma, JP;
Hitachi, Ltd., Tokyo, JP;
Hitachi Maxwell, Ltd., Osaka, JP;
Abstract
A magneto-optical disk which has a circular disk form and comprises a substrate provided with information pits and a guide groove, a recording medium layer provided on the substrate, and a protective layer formed of at least one thin film on the medium layer, in which the surface of the protective layer is minutely roughened to have a concave rough pattern and not to substantially protrude beyond a reference level composed of the outermost surface portions of the protective layer. When the magneto-optical disk is subjected to recording by a CSS system using an air floating magnetic head conforming to high-frequency recording in a magnetic field modulation type recording, which is one of methods of overwrite recording on magneto-optical disks, the minute concave rough pattern formed on the surface of the disk substrate prevents such troubles as adhesion of the magnetic head to the surface of the disk and collision between the disk substrate being rotated and the head.