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:
Nov. 15, 1994
Filed:
Oct. 22, 1992
Kiyoshi Takahashi, Ibaraki, JP;
Mikio Murai, Hirakata, JP;
Masaru Odagiri, Kawanishi, JP;
Hideyuki Ueda, Takatsuki, JP;
Yukikazu Ohchi, Kadoma, JP;
Tatsuya Hiwatashi, Kumamoto, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A magnetic recording medium comprising: a non-magnetic substrate; a ferromagnetic metal thin film provided on the non-magnetic substrate; a filmlike first carbon layer provided on the ferromagnetic metal thin film; and a hard and amorphous second carbon layer provided on the first carbon layer; the first and second carbon layers having first and second Raman spectra based on Raman spectrophotometry, respectively; assuming that when each of the first and second Raman spectra is decomposed into a first band of Gaussian function having a peak in the vicinity of 1380 cm.sup.-1 and a second band of Gaussian function having a peak in the vicinity of 1550 cm.sup.-1 in X-Y rectangular coordinates with an X-axis expressed in cm.sup.-1 and a Y-axis indicative of spectral intensity, a ratio of an area enclosed by the first band and the X-axis to an area enclosed by the second band and the X-axis represents 'relative intensity', the first carbon layer has a relative intensity of 2 to 20, while the second carbon layer has a relative intensity of 0.8 to 3, a Vickers hardness of not less than 1,000 kg/mm.sup.2 and a thickness of 50 to 300 .ANG..