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:
Jun. 29, 1993
Filed:
Dec. 17, 1991
Keishi Nakashima, Nagaoka, JP;
Tsuyoshi Tosho, Nagaoka, JP;
Alps Electric Co., Ltd., Tokyo, JP;
Abstract
An object of the present invention is to provide a thin-film magnetic head device capable of magnetically writing magnetic signals into a magnetic recording medium having a high coercive force and reading the same therefrom. At least one of upper and lower magnetic layers is composed of a main magnetic layer and a sub magnetic layer. The sub magnetic layer has a saturation magnetic flux density of 1.5T or greater, a magnetic permeability of 1000 or less and an anisotropic magnetic field of 10 Oe or greater. The thickness of the sub magnetic layer should preferably be 0.5 .mu.m or less. According to the present invention, the sub magnetic layer can obtain a high saturation magnetic flux density and the main magnetic layer can attain a high magnetic permeability. With a thickness of 0.5 .mu.m or less, the sub magnetic layer can obtain a high saturation magnetic flux density without reducing the magnetic permeability.