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:
Sep. 12, 1989
Filed:
Aug. 12, 1987
Yujiro Fukuda, Machida, JP;
Shigeo Utsumi, Yokohama, JP;
Kichinojyo Tomitaka, Yokohama, JP;
Toshifumi Takisawa, Tokyo, JP;
Diafoil Company, Limited, Tokyo, JP;
Abstract
Disclosed herein is a biaxially oriented polyester film for magnetic recording media, containing uniformly carbon black particles and having the following specific properties: ##EQU1## wherein T.sub.900 represents a light transmittance of the film at a wavelength of 900 nm, Ra represents an average surface roughness of the film n.sub.1 represents the number of protuberances of 0.81 to 1.08 .mu.m in height existing on the surface of the film per film area of 25 cm.sup.2, and n.sub.2 represents the number of protuberances of more than 1.08 .mu.m in height existing on the surface of the film per film area of 25 cm.sup.2.