US 6,142,761 AGranted

Optical disc molding apparatus

AssigneeSony Corporation

InventorsNobuyuki Arakawa, Yuji Akiyama, Ken Minemura

Life of this patent

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Abstract

An optical disc molding apparatus is able to mold an optical disc in which the occurrence of swollen portions of trumpet shape on the upper and lower surfaces of on the outer peripheral portion of a disc base may be minimized and in which a burr may be prevented from being produced on the outer peripheral portion of the disc base. In the optical disc molding apparatus having a ring (6) for molding an outer diameter portion of a disc base and holding a stamper (5) for transfer a signal pit, a holding surface of the ring (6) for holding the stamper (5) is formed as the concave and convex surfaces comprising a plurality of concentric land portions (21) and a plurality of concentric groove portions (22). The outer peripheral surface of the stamper (5) is held by each land portion (21) with a pressure.

Claims3

Dependent claims

An optical disc molding apparatus comprising:

a pair of dies movable side in a relative fashion;
a pair of metal molds for forming a cavity therebetween;
a stamper for transferring an information pit on a disc;
and
a ring attached to said metal molds, having a holding surface for holding said stamper, said holding surface having a plurality of grooves and holding an outer peripheral surface of said stamper with convex surfaces of said grooves and molding an outer peripheral surface of said disc;
wherein said ring is urged against an inner diameter surface of a metal mold to which an outer diameter surface of said ring is attached in such a manner that said ring and said inner diameter surface have no clearance produced therebetween;
wherein one of said dies has on its one inner peripheral surface formed concave and convex portions, said ring has on its outer peripheral surface formed concave and convex portions and said ring is attached to said die and said metal mold by engaging said concave and convex portions with each other.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/127,917Filed 3 Aug 1998
Priority: JP 9-2092244 Aug 1997
Granted: 7 Nov 2000
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

B29C 45/2632
With mould wall parts provided with fine grooves or impressions, e.g. for record discs: stampers; Mountings thereof
B29C 45/263
Moulds: with mould wall parts provided with fine grooves or impressions, e.g. for record discs
B29C 2045/2648
With mould wall parts provided with fine grooves or impressions, e.g. for record discs: outer peripheral ring constructions
Y10S 425/81
Plastic article or earthenware shaping or treating: apparatus: sound record