Patent ID: 7322816
Filing Date: 2008-01-29
Classification: B29C,B29D,Y10S

Abstract:
1. A mold for forming a first disk substrate having a first surface having a no information area and a second surface on an opposite side of the first surface of the first disk substrate, the first disk substrate being bonded to a second disk substrate by an adhesive, the second disk substrate having a first surface having an information area and a second surface on an opposite side of the first surface of the second disk substrate, the no information area on the first disk substrate being formed in the same position as the information area on the second disk substrate, the first disk substrate having a groove formed therein, and the no information area on the first surface of the first disk substrate is adhesively bonded to the information area on the first surface of the second disk substrate, the mold comprising: a first mirror-surfaced plate forming a first surface of a cavity of said mold corresponding to the no information area on the first surface of the first disk substrate, the first mirror-surfaced plate comprising an inner hole in which a cylindrical member is inserted and fitted, said cylindrical member comprising an annular projection provided on its end surface adjacent to the cavity for forming the annular groove on the first surface of the first disk substrate; a second mirror-surfaced plate forming a second surface of the cavity of said mold opposed to said first mirror-surfaced plate; an annular air discharge groove, which opens into the cavity, and formed radially outside of said annular projection, and wherein the first mirror-surfaced plate and the cylindrical member constitute means for directly forming the first surface of the first disk substrate, and the second mirror-surfaced plate constitutes means for directly forming the second surface of the first disk substrate; wherein when the first and second disk substrates are bonded together, the first surface of the first disk substrate faces the first surface of the second disk substrate; and wherein the cylindrical member is stepped radially to form a shoulder portion that faces a surface of the first mirror-surfaced plate, and the mold comprises a spacer positioned between the shoulder portion and the surface of the first mirror-surfaced plate to space the cylindrical member such that the end surface of the cylindrical member is flush with the first cavity surface.