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:
Jul. 20, 1999
Filed:
Mar. 15, 1996
Andrew Chiu, San Jose, CA (US);
Cherngye Hwang, San Jose, CA (US);
Randall George Simmons, San Jose, CA (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A dual gap horizontal thin film inductive head is provided which writes wide and reads narrow so as to avoid noise problems when reading an information track on a magnetic medium. The head has first and second gap layers between first and second horizontal pole tips. The pole tips and the corresponding pole pieces of the head are constructed of a high magnetic moment material, such as NiFe (Permalloy). The first gap layer is constructed of a magnetic insulator, such as tungsten, and the second gap layer is constructed of a low magnetic moment material, such as NiFeCr. Accordingly, the magnetic moment of the second gap layer is lower than the magnetic moment of the first and second pole tips and the corresponding first and second pole pieces. During recording both gap layers function as a gap because the second gap layer is saturated and behaves as a magnetic insulator. During playback only the first gap layer functions a gap because the second gap layer is not saturated causing it to behave as a magnetic conductor. Accordingly, during record the head 'writes wide' and during playback the head 'reads narrow.' A unique method is provided for making the head which employs a vertical edge of a photoresist layer for forming the first and second gap layers.