Optical recording media having optically-variable security properties
US5549953A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 29, 1993 |
| Grant date | Aug 27, 1996 |
| Priority date | — |
| Expiry date | Apr 29, 2013 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/21
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
The prevention of counterfeiting of currencies, passports, cheques, bank cards, credit cards, optical disks and the like is addressed by introducing thin film structures having both optically-variable security properties and encoded optical data decodable by optical means. The thin film structures comprise a substrate and a multilayer interference coating carried by the substrate, producing an inherent color shift with a change of viewing angle. The multilayer interference coating has a dielectric material which is transparent and the recording layer made of a light absorbing material, a crystalline-structural changing material or a magneto-optic material. The encoded data is in the form of bar codes or digital data. The information is encoded by photolithographic means or by optical recording means. The encoded data is retrieved by an optical recording system having a light source and an optical guiding system and a light detector.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.