Method and apparatus for manufacturing hybrid discs
US7042475B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 29, 2003 |
| Grant date | May 9, 2006 |
| Priority date | — |
| Expiry date | May 10, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0903
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for manufacturing hybrid disc whose recordable-band grooves are wider and shallower than the pre-recorded ROM data pits. The ROM pits may be pre-recorded in ROM grooves that are at least as wide, but shallower than, the ROM pits. The ROM lands intervene between consecutive ROM pits, whether or not a ROM groove is provided. In the preferred embodiment, one beam of a dual beam apparatus records the ROM pits, while the other beam records the pre-grooves, and also records the ROM groove, if present. In most embodiments a thermal mastering process provides smooth feature surfaces to facilitate replication of the hybrid disc masters. The berms normally forming at the radial extremities of the pits and grooves in the masters, by thermal expulsion processes, may be reduced or eliminated by methods taught.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.