Mark forming apparatus, method of forming laser mark on optical disk, reproducing apparatus, optical disk and method of producing optical disk
US5761301A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 17, 1995 |
| Grant date | Jun 2, 1998 |
| Priority date | — |
| Expiry date | Nov 17, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2220/2562
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An object of the present invention is to provide a marking forming apparatus, a method of forming a laser marking on an optical disk, a reproduction apparatus, an optical disk, and a method of manufacturing an optical disk, capable of providing a greatly improved copy prevention capability as compared to prior known construction. To achieve this object, in the optical disk of the invention, for example, a marking is formed by a laser on a reflective film of a disk holding data written thereon and at least position information of the marking or information concerning the position information is written on the disk in an encrypted form or with a digital signature appended thereto.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.