Optically variable printing ink

• US 5,171,363 A
• Filed: 06/21/1991
• Issued: 12/15/1992
• Est. Priority Date: 12/28/1979
• Status: Expired due to Term

• Current Assignee: Viavi Solutions, Inc. (Lumentum Holdings Inc.)
• Original Assignee: Flex Products Incorporated (Sicpa Holding SA)
• Inventors: Mayer, Thomas, Phillips, Roger W., Ash, Gary S.
• Primary Examiner(s): Group, Karl
• Assistant Examiner(s): KLEMANSKI, HELENE G
• Application Number:
  US07/719,166
• Time in Patent Office: 543 Days
• Field of Search: 106/20, 106/22, 106/23, 106/287.17, 106/403, 106/404, 106/415, 356/71
• US Class Current: 106/31.65
• CPC Class Codes: B05D 1/286 using a temporary backing to which the coating has been applied
• CPC Class Codes: B05D 5/06 to obtain multicolour or other optical effects B05D5/02 takes precedence
• CPC Class Codes: B41M 3/00 Printing processes to produce particular kinds of printed work, e.g. patterns printing apparatus or machines of special type or for particular purposes B41F17/00; special designs or pictures per se B44F; manufacturing printed circuits using printing techniques H05K3/12 ; manufacturing organic semiconductor devices using printing techniques H10K71/13
• CPC Class Codes: B41M 3/14 Security printing securities B42D25/29
• CPC Class Codes: C01P 2004/54 Particles characterised by their aspect ratio, i.e. the ratio of sizes in the longest to the shortest dimension
• CPC Class Codes: C03C 17/00 Surface treatment of glass, not in the form of fibres or filaments, by coating optical coatings of optical elements G02B1/10
• 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: C09C 1/0051 comprising a stack of coating layers with alternating low and high refractive indices, wherein the first coating layer on the core surface has the low refractive index
• CPC Class Codes: C09C 1/0078 Pigments consisting of flaky, non-metallic substrates, characterised by a surface-region containing free metal
• CPC Class Codes: C09C 2200/1008 comprising at least one metal layer adjacent to the core material, e.g. core-M or M-core-M
• CPC Class Codes: C09C 2200/1054 the core consisting of a metal
• CPC Class Codes: C09C 2220/20 PVD, CVD methods or coating in a gas-phase using a fluidized bed
• CPC Class Codes: C09D 11/50 Sympathetic, colour changing or similar inks
• CPC Class Codes: F24S 70/225 for spectrally selective absorption
• CPC Class Codes: Y02E 10/40 Solar thermal energy, e.g. solar towers
• CPC Class Codes: Y10S 428/914 Transfer or decalcomania
• CPC Class Codes: Y10S 428/915 Fraud or tamper detecting
• CPC Class Codes: Y10T 428/24843 with heat sealable or heat releasable adhesive layer
• CPC Class Codes: Y10T 428/2486 with outer strippable or release layer
• CPC Class Codes: Y10T 428/24917 including metal layer
• CPC Class Codes: Y10T 428/2813 : Heat or solvent activated or sealable
• CPC Class Codes: Y10T 428/2839 : with release or antistick coating
• CPC Class Codes: Y10T 428/31678 : Of metal

Abstract

Articles and methods for forming optically variable thin film flakes and replicated coatings having preselected optical properties. The articles generally comprise a flexible web of material and an optically variable thin film coating formed on one surface of the web. The optically variable coating is separated from the web to form optically variable thin film flakes. The flakes are disposed in ink and paint vehicles to provide optically variable inks, paints and the like.

Claims

1. An optically variable printing ink for obtaining a color shift between two distinct colors at first and second angles of incident light, a liquid ink vehicle and optically variable flakes disposed in the ink vehicle, the optically variable flakes being comprised of a multilayer thin film structure having first and second planar surfaces, the optically variable flakes having a physical thickness which is measured in a direction perpendicular to the layers of the thin film structure and having an aspect ratio of at least 2 to 1 respectively for the first and second surfaces parallel to the planes of the layers of the thin film structure and surfaces perpendicular to the planes of the layers, the optically variable flakes having a maximum dimension ranging from approximately two to twenty microns.

2. An ink as in claim 1 together with a substantially transparent pigment dispersed in the a ink vehicle for blocking out an undesired color or modifying a color in the spectrum.

3. An ink as in claim 2 wherein said multilayer thin film structure provides a green-to-gold color shift and wherein the pigment is a yellow pigment.

4. An ink as in claim 1 wherein said optically variable flakes constitute from 15 to 50% by weight of the ink.

5. An ink as in claim 1 wherein the multilayer thin film structure is symmetrical when viewed in reflection from either of said first and second surfaces and is comprised of a central reflecting layer with a dielectric layer on each side of the central reflecting layer and a thin substantially transparent absorbing layer disposed on the dielectric layers.