Thin film structure having magnetic and color shifting properties

• US 4,838,648 A
• Filed: 05/03/1988
• Issued: 06/13/1989
• Est. Priority Date: 05/03/1988
• Status: Expired due to Term

• Current Assignee: Viavi Solutions, Inc. (Lumentum Holdings Inc.)
• Original Assignee: Optical Coating Laboratory, Inc. (Lumentum Holdings Inc.)
• Inventors: Phillips, Roger W., Coombs, Paul G.
• Primary Examiner(s): Arnold, Bruce Y.
• Application Number:
  US07/189,779
• Time in Patent Office: 406 Days
• Field of Search: 350/166, 283/91, 283/94, 283/902
• US Class Current: 359/585
• CPC Class Codes: C01P 2006/42 Magnetic properties
• CPC Class Codes: C09C 1/0015 Pigments exhibiting interference colours, e.g. transparent platelets of appropriate thinness or flaky substrates, e.g. mica, bearing appropriate thin transparent coatings
• CPC Class Codes: G02B 5/285 comprising deposited thin solid films G02B5/281 - G02B5/289 take precedence; multilayered film filters for fibre optic multiplexing G02B6/29361
• CPC Class Codes: G06K 19/10 at least one kind of marking being used for authentication, e.g. of credit or identity cards verification of coded identity or credit cards in mechanisms actuated by them G07F7/12
• CPC Class Codes: G11B 7/24 Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the arrangement of information on the carrier G11B7/007
• CPC Class Codes: Y10S 283/902 Anti-photocopy

Abstract

Thin film structure having magnetic properties and optically variable properties comprising a substrate and a multilayer interference coating carried by the substrate producing an inherent color shift with angle. The interference coating has a metal-dielectric design which includes a metal which has magnetic as well as reflective properties.

Claims

1. In a thin film structure having magnetic properties and optically variable properties, a substrate and a multilayer interference coating carried by the substrate producing an inherent color shift with angle, said interference coating having a metal-dielectric design which includes a metal which has magnetic as well as reflective properties.

2. A structure as in claim 1 wherein said metal having reflecting and magnetic properties is a cobalt nickel alloy.

3. A structure as in claim 2 wherein said cobalt nickel alloy is a composition of 80% cobalt and 20% nickel by weight plus or minus 10% for each metal in the alloy.

4. A structure as in claim 1 together with subtractive colorant means external of the multilayer interference coating on the side of the multilayer interference coating facing the incident light, said subtractive colorant means in combination with a multilayer interference coating serving to modify the inherent color shift produced by the multilayer interference coating to provide a discrete color shift from one distinct color to another color at two different angles of incidence.

5. A structure as in claim 1 wherein said subtractive colorant means is in the form of a dyed superstrate.

6. A structure as in claim 1 together with a release layer disposed between the interference coating and the substrate.

7. A structure as in claim 6 together with an adhesive carried by the interference coating, said adhesive being exposed to the ambient.

8. A structure as in claim 7 wherein said metallic layer having highly reflecting and magnetic properties is comprised of a cobalt nickel alloy.

9. A structure in claim 6 together with subtractive colorant means carried by each of the opposite sides of the symmetrical multilayer interference coating.

10. In a thin film structure having substantial color shift with angle of light incidence and viewing, a symmetrical multilayer interference coating producing an inherent color shift with angle, said symmetrical multilayer interference coating being a metal layer formed of a metal which is highly reflecting and which has magnetic properties and a dielectric layer disposed on opposite sides of the metal layer and a metallic absorber layer disposed on each of the dielectric spacer layers.

11. A structure as in claim 10 wherein said cobalt nickel alloy has a composition of approximately 80-20% by weight respectively of cobalt and nickel plus or minus 10% for each metal in the alloy.