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1. (WO2005112023) OPTICAL DISC AND MANUFACTURING METHOD THEREOF

Pub. No.:    WO/2005/112023    International Application No.:    PCT/JP2005/009018
Publication Date: Nov 24, 2005 International Filing Date: May 11, 2005
IPC: G11B 7/26
G11B 7/24
Applicants: SONY DISC & DIGITAL SOLUTIONS INC.
株式会社ソニー・ディスクアンドデジタルソリューションズ
YOSHIMURA, Hideaki
吉村 英昭
Inventors: YOSHIMURA, Hideaki
吉村 英昭
Title: OPTICAL DISC AND MANUFACTURING METHOD THEREOF
Abstract:
A resin film is manufactured by melt extrusion by applying heat on a resin material for plasticization at the time of manufacturing the resin film to be used for a light transmitting layer of an optical disc. The molecular weight of the resin material to be used for the resin film is the same as that of a resin material to be used for a disc board. Since the shrinking ratio of the resin film can be almost the same as that of the disc board to be laminated on the resin film, the resin film and the disc board shrink by the same ratio, respectively, even with time, and disc warping can be prevented. Furthermore, since complicated processes suchas anneal processing and equipment for such processes are not required, a large quantity of discs can be manufactured at a low cost in a short time.