
US Patent No: 5,549,953
Number of patents in Portfolio can not be more than 2000
Optical recording media having optically-variable security properties
Stats
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Aug 27, 1996
Issued date -
Apr 29, 1993
filing date -
08/053,678
serial no -
Expired
status
Importance
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.
First Claim
Related Publications
International Classification(s)
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Cited Art
| Patent Info | (Count) | # Cites | Year |
|---|---|---|---|
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| 5,147,701 Information recording medium | 13 | 1989 | |
| 5,154,957 Optical information recording medium | 25 | 1991 | |
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| 5,196,250 Optical information recording medium | 15 | 1991 | |