Apparatus and method for making a video disc
US4447381A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 8, 1982 |
| Grant date | May 8, 1984 |
| Priority date | — |
| Expiry date | Nov 8, 2002 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S425/81
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A video disc is molded in an apparatus which includes a pair of opposed mold members each having a mold cavity in its surface which faces the other mold member and a stamper is mounted across the mold cavity in each of the mold members. Each stamper has on its surface a surface relief pattern arranged along a spiral path. The stampers are arranged on the mold members so that any imperfections in the mold members which may pass through the stampers and be impressed on the disc being molded are aligned with areas of the stamper which do not contain information which impacts the picture quality so that such imperfections are impressed in areas of the disc which will not adversely impact the perceived picture quality during playback of the disc.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.