Apparatus for molding magneto-optic substrates
US4898529A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 29, 1988 |
| Grant date | Feb 6, 1990 |
| Priority date | — |
| Expiry date | Dec 29, 2008 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S425/81
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Apparatus for molding a substrate for use in supporting a magneto-optic recording structure includes a mold having a cavity that defines a plane and that is designed to form a thin disk-like magneto-optic substrate. The mold is mounted with such plane horizontal and an axis of circular symmetry thereof substantially vertical. Hot fluid plastic flows from the center of such horizontal mold so that the fluid plastic flows horizontally and relatively uniformly and radially outwardly from the center of the mold to minimize azimuthal variations in birefringence. Such flowing is by injection molding. The molding apparatus for manufacturing such magneto-optic substrate includes a support for positioning such mold with the plane thereof horizontal. Hot fluid plastic is injected to the center of such mold, as for example from the vertical axis of symmetry of such mold. With the plane of the mold horizontal and the hot fluid plastic flowing horizontally radially and symmetrically outwardly from the center of the mold, the fluid plastic moves substantially horizontally radially and uniformly through the mold. The resulting magneto-optic substrate has relatively small azimuthal variation in bi…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.