Information recording media and optical disk, disk having specific data so that a visible pattern of characters or graphics appear on a copy disk
US5751671A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 12, 1995 |
| Grant date | May 12, 1998 |
| Priority date | — |
| Expiry date | Apr 12, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/007
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A character and/or graphics pattern area for recording specific data is provided on a CD-ROM. When an original disk is prepared, a specific pit pattern corresponding to the specific data is recorded at a first predetermined tracking linear velocity controlled by a specific tracking linear velocity control system for each track so that a character and/or graphics pattern cannot be identified. When a copy disk is produced from the original disk, if data is recorded at a second tracking linear velocity controlled by a specific tracking linear velocity control system, the character and/or graphics pattern of visible size appears on the copy disk because of an optical reflection factor difference between areas caused by placement of the specific pit pattern corresponding to the specific data.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.