Methods and apparatus for rendering an optically encoded medium unreadable and tamper-resistant
US6780564B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 30, 2002 |
| Grant date | Aug 24, 2004 |
| Priority date | — |
| Expiry date | Jul 30, 2022 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S430/146
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
“Methods and apparatus are provided for making an optically readable media unreadable and tamper-resistant. A method has steps of (a)providing the media with a readout surface layer that is non-flat (i.e., texture in some way, such as by embossing, scratching, depositing a non-flat layer or regions, such as droplets) and that inhibits optical readout of the media; (b) applying a coating layer to the non-flat surface layer to smooth the non-flat surface and to enable optical readout of the media; and, after an initiation of a readout period, (c) removing the coating layer so as to expose the non-flat readout surface layer, thereby inhibiting optical readout of the media. Preferably, the coating layer is substantially index matched to the readout surface layer. The step of removing includes at least one of evaporating or subliming a component material of the coating layer A method is also disclosed for discouraging tampering with a readout-limiting mechanism by (a) providing the media with at least one layer that embodies the readout-limiting mechanism; (b) providing a textured surface that forms part of a layer that underlies the at least one layer, where the textured surface …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.