| 摘要 |
PURPOSE:To prevent the adsorption of a head to the surface of a magnetic disk by concentrically forming many circular grooves having a specified width, depth and pitch on a thermoplastic resin disk having a mirror finished surface. CONSTITUTION:Many circular grooves having 500-20,000Angstrom , preferably 1,000-10,000Angstrom width, 200-2,000Angstrom , preferably 500-1,000Angstrom depth and 1,000-20,000Angstrom , preferably 2,000-20,000Angstrom pitch are concentrically formed on a thermoplastic resin disk having a mirror finished surface. When the width and pitch of the grooves are not within the range of 500-20,000Angstrom and the range of 1,000-20,000Angstrom , respectively, the grooves are not effective in preventing the adsorption of a head. In case of <200Angstrom depth, the grooves are not effective in preventing the adsorption. In case of >2,000Angstrom depth, the interval between a head and the surface of a magnetic disk is increased and the reproduction output is reduced.
|
