Fabrication of foil disc pressing matrices
US3956075A · kind A · utility
4Cited by
5References
5Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Feb 21, 1974 |
| Grant date | May 11, 1976 |
| Priority date | — |
| Expiry date | Feb 21, 1994 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B3/56
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A matrix, which is to be employed for pressing foil disc copies carrying a spiral groove which is highly concentric to the axis of disc rotation, is formed by electrodeposition from a lacquer foil original which is cut to form a groove corresponding to such spiral groove and to form additional grooves deeper than the spiral groove and having a form that produces, on the matrix, sharp edges capable of directly cutting the outer periphery and center hole of a foil disc copy.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.