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:
Dec. 14, 1993
Filed:
Apr. 17, 1990
Toshimitsu Kaku, Sagamihara, JP;
Shigeru Nakamura, Tachikawa, JP;
Masahiko Takahashi, Hachioji, JP;
Toshio Niihara, Sayama, JP;
Harukazu Miyamoto, Kodaira, JP;
Norio Ohta, Iruma, JP;
Takeshi Nakao, Sagamihara, JP;
Hirofumi Sukeda, Kokubunji, JP;
Masahiro Ojima, Tokyo, JP;
Takashi Toyooka, Sayama, JP;
Tsuneo Suganuma, Tokorozawa, JP;
Fumiyoshi Kirino, Tokyo, JP;
Yoshinori Miyamura, Tokyo, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A magnetic field of a polarity corresponding to information to be recorded is applied while a recording spot having a high energy is irradiated to a magneto-optical recording medium to record domains representing the information along a track. The recorded domains are read out by a reproducing spot having a lower energy than the recording spot and a high resolution power along the track. A recording head has an optical system for irradiating the recording spot having the high energy to the magneto-optical recording medium and a magnetic head for applying a magnetic field having a polarity thereof switched in accordance with the information to be recorded, to an irradiation area of the recording spot, a reproducing head has an optical system for irradiating the reproducing spot having the low energy by a laser beam having a wavelength of no larger than 600 nm and a magneto-optical signal detector for detecting a displacement of a polarization plane of a reflected light of the reproducing spot to read out the recording domains. The magneto-optical recording medium is made of a recording film having a multi-layer structure of alternate lamination of metal layers and dielectric layers.