Rewritable type optical disc including recording marks over break portions of recording tracks, manufacturing method and manufacturing system therefor
US7230899B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 30, 2001 |
| Grant date | Jun 12, 2007 |
| Priority date | — |
| Expiry date | Jul 9, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B23/281
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A rewritable type optical disc includes recording tracks formed with break portions; and recording marks corresponding to predetermined data and formed on the recording tracks. The recording marks are formed over the break portions on the recording tracks. If the predetermined data, such as control data, recorded as the recording mark is illegally altered, the position of the recording marks are changed and some break portions are not covered by the recording marks. Since the return light level of the break portion, which is not covered by the recording mark, is different from the return light level of the break portion covered by the recording mark, such illegal alteration of the predetermined data such as the control data may be detected.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.