Transient optical state change materials useful in copy-protected compact discs
US7344823B2 · kind B2 · utility
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5Claims
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Key dates
| Filing date | Sep 26, 2003 |
| Grant date | Mar 18, 2008 |
| Priority date | — |
| Expiry date | Sep 26, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B20/00608
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A copy-protected optical medium comprising transient optical state change security materials that demonstrating an optical state change when exposed to the wavelengths of from about 770 nm to about 830 nm.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.