Document Type and Number:
Japanese Patent JPS49119601
Kind Code:
A
Abstract:
A matrix, which is to be employed for pressing foil disc copies carrying a spiral groove which is highly concentric to the axis of disc rotation, is formed by electrodeposition from a lacquer foil original which is cut to form a groove corresponding to such spiral groove and to form additional grooves deeper than the spiral groove and having a form that produces, on the matrix, sharp edges capable of directly cutting the outer periphery and center hole of a foil disc copy.
Application Number:
JP1983874A
Publication Date:
November 15, 1974
Filing Date:
February 19, 1974
Export Citation:
International Classes:
G11B3/70; B29C43/00; B29C43/02; B29C61/00; B29D17/00; G11B3/56; (IPC1-7): G11B3/56