Process for producing substrate of optical disc
US4961884A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 31, 1989 |
| Grant date | Oct 9, 1990 |
| Priority date | — |
| Expiry date | Jul 31, 2009 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S425/81
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
An improved injection molding process for producing a substrate of an optical disc having a high quality is disclosed. The process includes the steps of: fixing a stamper having protrusions corresponding to pits for recorded information or a groove for tracking onto one mold unit of a pair of mold units of an injection molding machine; combining the mold units to form a closed cavity between the pair of mold units; charging a molten molding resin into the cavity; cooling the resin in the cavity to form a molded substrate; separating one mold unit from another mold unit; and releasing the molded substrate simultaneously from both mold units when the two mold units are separated from each other by applying pressurized air onto both sides of the substrate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.