Alignable diffractive pigment flakes

• US 6,902,807 B1
• Filed: 09/13/2002
• Issued: 06/07/2005
• Est. Priority Date: 09/13/2002
• Status: Expired due to Term

• Current Assignee: Viavi Solutions, Inc. (Lumentum Holdings Inc.)
• Original Assignee: Flex Products Incorporated (Sicpa Holding SA)
• Inventors: Chu, Dishuan, Raksha, Vladimir P., Argoitia, Alberto
• Primary Examiner(s): Le, H. Thi
• Application Number:
  US10/243,111
• Time in Patent Office: 998 Days
• Field of Search: 428/403, 428/323, 428/328, 428/32.36, 428/402, 406/31.13, 406/31.6, 406/31.65, 406/31.9
• US Class Current: 428/403
• CPC Class Codes: B41M 3/148 Transitory images, i.e. images only visible from certain viewing angles
• CPC Class Codes: B42D 2033/16 Magnetic or magnetisable material
• CPC Class Codes: B42D 2033/20 Coloured material; Pigments or inks
• CPC Class Codes: B42D 25/29 Securities; Bank notes
• CPC Class Codes: B42D 25/328 Diffraction gratings; Holograms
• CPC Class Codes: B42D 25/369 Magnetised or magnetisable materials
• 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: 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: C09C 1/0078 Pigments consisting of flaky, non-metallic substrates, characterised by a surface-region containing free metal
• CPC Class Codes: C09C 2200/30 Interference pigments characterised by the thickness of the core or layers thereon or by the total thickness of the final pigment particle
• CPC Class Codes: C09C 2200/40 Interference pigments comprising an outermost surface coating
• CPC Class Codes: C09C 2210/30 A layer or the substrate forming a grating
• CPC Class Codes: C09D 11/50 Sympathetic, colour changing or similar inks
• CPC Class Codes: C09D 5/36 Pearl essence, e.g. coatings containing platelet-like pigments for pearl lustre
• CPC Class Codes: G03H 1/0244 Surface relief holograms replicating hologram without interference recording G03H1/0276
• CPC Class Codes: G03H 1/028 by embossing
• CPC Class Codes: G03H 2270/24 Having particular size, e.g. microscopic
• CPC Class Codes: H01F 10/12 being metals or alloys intermetallic compounds H01F10/18
• CPC Class Codes: Y10T 428/24372 Particulate matter
• CPC Class Codes: Y10T 428/2438 : Coated
• CPC Class Codes: Y10T 428/24413 : Metal or metal compound
• CPC Class Codes: Y10T 428/24893 : including particulate material
• CPC Class Codes: Y10T 428/25 : Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
• CPC Class Codes: Y10T 428/256 : Heavy metal or aluminum or compound thereof
• CPC Class Codes: Y10T 428/2982 : Particulate matter [e.g., sphere, flake, etc.]
• CPC Class Codes: Y10T 428/2991 : Coated

Abstract

Diffractive pigment flakes are selectively aligned to form an image. In one embodiment, flakes having a magnetic layer are shaped to facilitate alignment in a magnetic field. In another embodiment, the flakes include a magnetically discontinuous layer. In a particular embodiment, deposition of nickel on a diffraction grating pattern produces magnetic needles along the grating pattern that allow magnetic alignment of the resulting diffractive pigment flakes. Color scans of test samples of magnetically aligned flakes show high differentiation between illumination parallel and perpendicular to the direction of alignment of the magnetic diffractive pigment flakes.

Claims

1. A pigment particle comprising:

a non-symmetrical selectively shaped magnetic structure capable of orienting the pigment particle with respect to an applied magnetic field; and

a diffraction grating.

2. The pigment particle of claim 1 wherein the magnetic structure comprises shaped magnetic material.

3. The pigment particle of claim 1 wherein the magnetic structure comprises a semi-transparent magnetic material.

4. The pigment particle of claim 1 wherein the magnetic structure comprises nickel, cobalt, iron, gadolinium, terbium, dysprosium, erbium, Fe—

Si alloy, Fe—

Ni alloy, Fe—

Co alloy, Fe—

Ni—

Mo alloy, SmCo₅, NdCo₅, Sm₂Co₁₇, Nd₂Fe₁₄B, TbFe₂, Fe₃O₄, NiFe₂O₄, or CoFe₂O₄.

5. The pigment particle of claim 1 wherein the diffraction grating comprises a plurality of grooves.

6. The pigment particle of claim 5 wherein the plurality of grooves has a spacing of between 500 lines per mm and 5000 lines per mm.

7. The pigment particle of claim 5 wherein the magnetic structure comprises magnetic needles disposed parallel to the plurality of grooves of the diffraction grating.

8. The pigment particle of claim 7 wherein at least some of the magnetic needles are joined with intervening magnetic material.

9. The pigment particle of claim 1 wherein the magnetic structure comprises a layer of magnetic material having variable thickness.

10. The pigment particle of claim 9 wherein the layer of magnetic material is a continuous layer.

11. The pigment particle of claim 1 disposed in an ink vehicle to provide an ink formulation.

12. The pigment particle of claim 1 dispersed in a paint vehicle to provide a paint formulation.

13. The pigment particle of claim 1 dispersed in a polymeric sheet, the diffraction grating of the pigment particle being selectively oriented in the sheet.

14. The pigment particle claim 1 wherein the diffraction grating includes a first plurality of grooves extending along a first direction and a second plurality of grooves extending along a second direction.

15. The pigment particle of claim 1 wherein the diffraction grating includes a fist plurality of grooves having a first linear grating spacing and a second plurality of grooves having a second linear grating spacing.

16. The pigment particle of claim 1 wherein the diffraction grating includes grooves aligned along the applied magnetic field when the pigment particle is oriented.

17. A pigment particle comprising:

a magnetic structure capable of orienting the pigment particle with respect to an applied magnetic field; and

a diffraction grating, wherein the magnetic structure is a layer of magnetic material and the pigment particle has a shape facilitating orientation in the applied magnetic field.

18. The pigment particle of claim 17 wherein the magnetic structure comprises shaped magnetic material.

19. The pigment particle of claim 17 wherein the magnetic structure comprises a plurality of magnetic stripes.

20. The pigment particle of claim 17 wherein the magnetic structure comprises a semi-transparent magnetic material.

21. The pigment particle of claim 17 wherein the magnetic structure comprises nickel, cobalt, iron, gadolinium, terbium, dysprosium, erbium, Fe—

Si alloy, Fe—

Ni alloy, Fe—

Co alloy, Fe—

Ni—

Mo alloy, SmCo₅, NdCo₅, Sm₂Co₁₇, Nd₂Fe₁₄B, TbFe₂, Fe₃O₄, NiFe₂O₄, or CoFe₂O₄.

22. The pigment particle of claim 17 wherein the diffraction grating comprises a plurality of grooves.

23. The pigment particle of claim 22 wherein the plurality of grooves has a spacing of between 500 lines per mm 5000 lines per mm.

24. The pigment particle of claim 22 wherein the magnetic structure comprises magnetic needles disposed parallel to the plurality of grooves of the diffraction grating.

25. The pigment particle of claim 24 wherein at least some of the magnetic needles are joined with intervening magnetic material.

26. The pigment particle of claim 17 wherein the magnetic structure comprises a layer of magnetic material having variable thickness.

27. The pigment particle claim 26 wherein the layer of magnetic material is a continuous layer.

28. The pigment particle of claim 17 dispersed in an ink vehicle to provide an ink formulation.

29. The pigment particle of claim 17 dispersed in a paint vehicle to provide a paint formulation.

30. The pigment particle of claim 17 dispersed in a polymeric sheet, the diffraction grating of the pigment particle being selectively oriented in the sheet.

31. The pigment particle claim 17 wherein the diffraction grating includes a first plurality of grooves extending along a first direction and a second plurality of grooves extending along a second direction.

32. The pigment particle of claim 17 wherein the diffraction grating includes a first plurality of grooves having a first linear grating spacing and a second plurality of groves having a second linear grating spacing.

33. The pigment particle of claim 17 wherein the diffraction grating includes grooves aligned along the applied magnetic field when the pigment particle is oriented.

34. A pigment particle comprising:

a magnetic structure capable of orienting the pigment particle with respect to an applied magnetic field; and

a diffraction grating wherein the magnetic structure comprises a plurality of magnetic stripes.

35. A pigment particle comprising:

a reflective layer patterned to include a diffraction grating; and

a plurality of magnetic needles disposed along the diffraction grating.