Copy count protection structure for optical recording medium and method for same
US5963536A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 28, 1997 |
| Grant date | Oct 5, 1999 |
| Priority date | — |
| Expiry date | Oct 28, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/21
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical recording medium comprising a first substrate with a center mounting hole and having top and bottom surfaces. At least one surface of the substrate is a prerecorded area wherein user data is provided and adapted to be read in an optical recording medium reader device. Over at least a portion of the substrate that can be read by the device is a photosensitive layer comprising a photosensitive material. When the photosensitive material is exposed to a predefined wavelength of light over a predetermined period of time the optical property of at least a portion of the material permanently changes. This change occurs after each copy of the prerecorded area is made. Thereby, the optical recording medium limits the authorized copies of the prerecorded area to a predetermined number.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.