METHOD FOR FORMING OPTICAL DISC SUBSTRATE AND OPTICAL DISC SUBSTRATE

Title:

METHOD FOR FORMING OPTICAL DISC SUBSTRATE AND OPTICAL DISC SUBSTRATE

Document Type and Number:

Japanese Patent JPH0647787

Kind Code:

A

Abstract:

PURPOSE: To obtain an optical disc substrate which shows satisfactory group or pit transfer properties.

CONSTITUTION: A molding resin is completely filled within 0.35sec., and at the same time, the non-dimensional temperature Θ-(Tg-Tmo)/(Tme-Tmo) which is determined by a molding resin glass transition temperature Tg, and a die temperature Tmo and a resin temperature Tme during injection molding, should be 0.02≤Θ≤0.1, if the resin is molded, in an optical disc substrate having a narrow track pitch or land width. Consequently, it is possible to obtain the optical disc substrate having satisfactory group and pit transferability and excellent signal properties.

Inventors:

KURAMOTO HIROKI
YOSHII MASAKI
EBINUMA NAOTAKE

Application Number:

JP20214392A

Publication Date:

February 22, 1994

Filing Date:

July 29, 1992

Export Citation:

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Assignee:

HITACHI LTD

International Classes:

B29C45/77; B29C45/78; G11B7/2405; G11B7/2407; G11B7/24076; G11B7/24079; G11B7/24085; G11B7/26; G11B11/10; G11B11/105; B29L17/00; (IPC1-7): B29C45/78; B29C45/77; G11B7/24; G11B7/26; G11B11/10

Attorney, Agent or Firm:

Ogawa Katsuo

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