Method for injection molding of optical discs
US5897814A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 13, 1997 |
| Grant date | Apr 27, 1999 |
| Priority date | — |
| Expiry date | Jun 13, 2017 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C2045/2636
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
In a method for controlling the heat transfer in a process for molding an optical disc of the type having a plurality of laser readable depressions of a predetermined quality, the process steps include injecting molten thermoplastic material into a mold having opposing surfaces for replicating respective opposite sides of the disc and imparting optically readable depressions of a predetermined quality to at least one side of said disc, opposing thermally conductive members, and a pair of insulating members, with each insulating member positioned between said conductive mold body and a respective opposing thermally conductive member, maintaining said thermally conductive mold body at a temperature less then about 90 degrees Centigrade wherein said insulting members are selected so that the molten thermoplastic resin is evenly and rapidly cooled from opposing sides to a temperature within about 5 degrees Centigrade of the glass transition temperature of said resin.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.