Optical recording medium its manufacturing method and injection molding apparatus
US7224665B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 28, 2001 |
| Grant date | May 29, 2007 |
| Priority date | — |
| Expiry date | Jan 25, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B23/0035
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In an optical disc in which an information signal is recorded/reproduced by irradiating a laser beam to a disc substrate 1 in which an information signal portion 1c has been provided on one principal plane from the side where the information signal portion 1c exists, a clamp reference surface 3a is set to the information signal portion 1c side of a replica substrate 1a constructing the optical disc. The clamp reference surface 3a is set to a flat surface and a thickness of the replica substrate 1a in a clamping area 3 is set to be larger than that of the convex-shaped replica substrate 1a in an information recording area 4. The replica substrate 1a in which a periphery of a center hole 1b is thicker than the information recording area 4 is used.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.