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. 07, 1999
Filed:
Feb. 27, 1997
Sony Corporation, Tokyo, JP;
Abstract
This invention intends to offer a magnetic recording medium which is so devised as to give a wide dynamic range and a flat response over whole audible frequencies. This invention attains the object by providing a magnetic recording medium which has two magnetic layers each composed mainly of ferromagnetic powder and a binder spread one over the other on one surface (front surface) of a non-magnetic substrate, wherein the ferromagnetic powder of either magnetic layer has a coercive force of 54.0-59.0 kA/m, and the coercive forces of the two magnetic layers differ by 3.2 kA/m or less. In addition, if a phase shift has to be minimized, the frictional coefficient of the back surface, and roughness (Ra.sup.f) of the magnetic surface with respect to that (Ra.sup.b) of the back surface or Ra.sup.f /Ra.sup.b should be adjusted properly.