Read-only optical recording medium on which unique identification information is written
US7590042B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Apr 8, 2005 |
| Grant date | Sep 15, 2009 |
| Priority date | — |
| Expiry date | Oct 10, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/85
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
There is provided a method for recording an unique ID to a read-only optical disk (1) adopting the 1-7 PP modulation technique and having provided in a plurality of predetermined positions postscript areas each having a predetermined postscript pattern formed therein. The postscript pattern takes a form of 3T (pit)-2T (land)-3T (pit) and has a length of 8T (largest code length of a modulated bit string). Modulated bit strings before and after the 3T-2T-3T postscript pattern are formed so that the pit-land-pit postscript pattern complies with the rule of the variable-length modulation even when it is replaced as a whole with a pit-only pattern. Further, the land in the middle of the pit-land-pit postscript pattern is formed from a material which will not physically change when irradiated with laser light having a reading-level one but will be melted when irradiated with laser light having a power higher than the reading-level one.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.