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. 01, 1991
Filed:
Aug. 29, 1989
Applicant:
Inventors:
Hideto Sandaiji, Kasugai, JP;
Fuminori Takeya, Nagoya, JP;
Assignee:
NGK Insulators, Ltd., , JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
B23K / ;
U.S. Cl.
CPC ...
21912169 ; 156643 ; 156654 ; 21912168 ;
Abstract
A core for magnetic head, which has a groove depth of at least 10 .mu.m with a dimensional accuracy not lower than .+-.2 .mu.m in the groove for defining the track of the core, can be obtained by subjecting a gapped bar made of ferrite and/or Sendust to a laser-induced etching wherein a laser beam having a focused beam diameter of not larger than 50 .mu.m, preferably not larger than 20 .mu.m, and a laser power P in a specified range is irradiated at a scanning speed V that is within a range between 2 .mu.m/sec and 200 .mu.m/sec and delimited by the laser power P, in a phosphoric acid or alkali metal hydroxide aqueous solution.