Method of manufacturing optical-use plastic products
US5922250A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 3, 1997 |
| Grant date | Jul 13, 1999 |
| Priority date | — |
| Expiry date | Nov 3, 2017 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C2045/1682
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A method is provided for manufacturing an optical plastic article formed of a plastic resin composition and having a homogeneous construction and a surface shape within a predetermined dimensional accuracy. A first step includes injection molding melted resin of the plastic resin composition into a mold cavity to produce a primary molding. A second step includes injection molding melted resin of the plastic resin composition which is the same as in the first step over at least a portion of the primary molding to form a secondary molding melt-welded to the primary molding and having the surface shape within the predetermined dimensional accuracy. The secondary molding has a secondary molding maximum thickness less than a limit thickness at which shrinkage exceeds limits of the predetermined dimensional accuracy. The optical plastic article has an optical plastic article thickness defined by the primary molding and the secondary molding greater than the limit thickness. The primary molding is preferably preheated prior to the secondary molding being melt-welded thereto and can have a thickness greater than the limit thickness.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.