Method for rendering surface layer of limited play disk lightfast
US7374804B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Aug 23, 2005 |
| Grant date | May 20, 2008 |
| Priority date | — |
| Expiry date | Oct 11, 2025 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/21
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optically readable media (10) has an information-encoding layer (16) and at least one color-forming layer (12) that embodies an optical readout-limiting mechanism. In a first embodiment the at least one color-forming layer contains an additive that does not interfere with the optical readability of the media for a duration of a readout period. The additive, upon exposure to a source of optical radiation that is suitable for reversing the color-forming layer from an optical readout inhibiting state to an optical readout enabling state, undergoes a transformation that maintains the color-forming layer in the optical readout inhibiting state. More specifically, exposure to the source causes the color-forming layer to photobleach and the additive to oxidize, where the oxidation of the additive permanently inhibits the optical readability of the media. The additive may be a leuco dye. In one embodiment the color-forming layer is comprised of 3-[2,2-bis(4-diethylaminophenyl)vinyl]-6-dimethylaminophthalide and the additive is comprised of benzoyl leucomethylene blue. In a further embodiment the additive is placed into a protective layer (18) that overlies the color-forming layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.