Limited play optically-readable medium with liquid crystals and methodology therefor
US7504137B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 7, 2003 |
| Grant date | Mar 17, 2009 |
| Priority date | — |
| Expiry date | Sep 29, 2024 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09K2323/00
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method and an apparatus are disclosed for limiting the readability of optically-readable medium, wherein a combination of a liquid crystal material and a wavelength shifting material are incorporated into the optically-readable medium. The liquid crystal material is selected to substantially interfere with the reading beam of a reading device. The wavelength shifting material is selected to shift the wavelength at which the liquid crystal interferes with the reading beam so that the reading beam can read the optically-readable medium. A predetermined stimulus causes the liquid crystal material to shift back to a configuration that substantially interferes with the reading beam so that the reading beam can no longer read the content on the optically readable medium.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.