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.

Date of Patent:
Aug. 08, 1989

Filed:

Oct. 05, 1987
Applicant:
Inventors:

Hideki Akasaka, Yokohama, JP;

Masatoshi Sato, Tokyo, JP;

Assignee:

Nikon Corporation, Tokyo, JP;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B / ; G11B / ;
U.S. Cl.
CPC ...
369 13 ; 360 59 ; 360114 ; 365122 ;
Abstract

A magnetooptical recording method for recording data using a bit having upward-magnetization and a bit having downward-magnetization on a recording layer of a magnetooptical recording medium comprises the steps of using, as the medium, a multilayered magnetic recording medium consisting of a first layer having a perpendicular magnetic anisotropy acting as a recording layer, and a second layer having a perpendicular magnetic anisotropy acting as a reference layer; moving the medium; applying an initial field so that, before recording, the direction of magnetization of the recording layer is left unchanged, and that of the reference layer is aligned either upward or downward; radiating two adjacent laser beams, i.e., a leading beam and a trailing beam onto the medium; the leading beam being an erasing beam of low level which is not modulated in principle; the trailing beam is a writing beam which is pulse modulated between high level and basis level in accordance with binary data to be recorded; and the basis level being able to have an intensity equal to or lower than the low level and to be zero level; when the trailing laser beam is radiated, applying a bias field to the irradiated portion; and when the intensity of the pulse-modulated laser beam is at high level, forming one of the bit having upward-magnetization, and when the leading low-level laser beam is radiated, forming the other bit.


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