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:
Mar. 16, 1999
Filed:
Jun. 30, 1997
Kye-Chul Choi, Seoul, KR;
Keum-Mo Kim, Seoul, KR;
Kwang-Yong Eun, Seoul, KR;
Kwang-Ryeol Lee, Seoul, KR;
Daewoo Electronics Co., Ltd., Seoul, KR;
Abstract
An aluminum head drum for use in a video cassette recorder is coated with a protective layer comprising diamond-like carbon. The protective layer of diamond-like carbon is obtained using a plasma-enhanced chemical vapor deposition method and has a thickness ranging from 0.3 .mu.m to 2.0 .mu.m. The protective layer has a varying mechanical hardness, wherein the mechanical hardness has a maximum value at a region of the protective layer coming in contact with the aluminum head drum, decreases smoothly and continuously and reaches an minimum value at a region of the protective layer coming in contact with atmosphere. Micro-Vicker's hardness of the region of the protective layers coming in contact with a video tape is 1.5-2.0 times that of the magnetic substance constituting the video tape.