OPTICALLY VARIABLE DEVICE WITH DIFFRACTION-BASED MICRO-OPTICS, METHOD OF CREATING THE SAME, AND ARTICLE EMPLOYING THE SAME

• US 20070291362A1
• Filed: 06/20/2006
• Published: 12/20/2007
• Est. Priority Date: 06/20/2006
• Status: Active Grant

• Current Assignee: OpSec Security Group, Inc.
• Original Assignee: Applied Opsec, Inc.
• Inventors: Rowe, Andrew K., Hill, Dean R., Renton, Robert E., Dunn, Paul
• Granted Patent: US 8,488,242 B2
• Time in Patent Office: Days
• US Class Current: 359/567
• CPC Class Codes: B42D 2035/24 Colours
• CPC Class Codes: B42D 2035/44 Miniaturised markings
• CPC Class Codes: B42D 25/29 Securities; Bank notes
• CPC Class Codes: B42D 25/328 Diffraction gratings; Holograms
• CPC Class Codes: B42D 25/342 Moiré effects
• CPC Class Codes: B42D 25/45 Associating two or more layers
• CPC Class Codes: G02B 5/1842 Gratings for image generation G02B5/1847 takes precedence
• CPC Class Codes: G02B 5/1885 Arranged as a periodic array

Abstract

A security device includes an optically variable device (OVD) having diffraction-based micro-optics including at least one moiré magnified visual representation of a micro-object. A diffractive structure provides micro-objects with unique optical effects when the OVD is viewed through the micro-object structure from a predetermined relative observation point. In addition to magnifying the micro-objects, the diffractive structure can impart optical effects such as change in observed color, enhanced contrast, animation of the observed visual representation, and change in size or shape of the observed visual representation. The micro-objects and the diffractive structure can be disposed on the same or different portions of a substrate. A method of making OVDs, and an article employing such OVDs are also disclosed.

Claims

1. An optically variable device comprising:

a substrate including a first portion and a second portion;

at least one micro-object disposed on the first portion of said substrate; and

a diffractive structure disposed on the second portion of said substrate,

wherein at least one magnified visual representation of said micro-object is observed when said optically variable device is observed from a predetermined relative observation point and said micro-object is disposed between said diffractive structure and said observation point.

2. The optically variable device of claim 1 wherein said substrate comprises a generally planar member including a first side and a second side;

wherein the first side is intermediate the second side and said predetermined relative observation point; and

wherein the second side is distal from said observation point.

3. The optically variable device of claim 2 wherein the first and second portions of said substrate are both at or about the second side of said substrate.

4. The optically variable device of claim 3 wherein said micro-object is integral with said diffractive structure.

5. The optically variable device of claim 2 wherein the first portion of said substrate is at or about the first side of said substrate;

and wherein the second portion of the substrate is at or about the second side of said substrate.

6. The optically variable device of claim 1 wherein said substrate comprises a material selected from the group consisting of a film, a laminate, a thread, a foil, a label, and a casting.

7. The optically variable device of claim 1 wherein said at least one micro-object comprises a plurality of micro-objects selectively organized in an object layer;

wherein said object layer is coupled to said substrate by an adhesive; and

wherein said object layer is removable from said substrate.

8. The optically variable device of claim 1 further comprising at least one additional layer selected from the group consisting of a metallic layer, a transparent refractive layer, a reflective layer, a protective layer, and an additional substrate.

9. The optically variable device of claim 1 wherein said diffractive structure comprises a plurality of diffractive elements selectively organized into a diffractive layer;

and wherein said diffractive elements of said diffractive layer are structured to diffract light at different wavelengths depending upon the predetermined relative observation point from which said optically variable device is viewed.

10. The optically variable device of claim 9 wherein in addition to said at least one magnified visual representation of said micro-object, said diffractive elements are structured to impart at least one additional predetermined optical effect selected from the group consisting of a change in observed color, enhanced contrast between said at least one magnified visual representation of said micro-object and background, a movement or animation of said at least one magnified visual representation, a change in the size or shape of said magnified visual representation, and a transformation of said magnified visual representation into a different object or optical effect.

11. The optically variable device of claim 1 wherein said optically variable device has a thickness;

and wherein the thickness of said optically variable device is about 5-250 microns.

12. An article comprising:

a surface; and

at least one security device coupled to said surface in order to resist counterfeiting of said article, said security device including at least one optically variable device with diffraction-based micro-optics, said optically variable device comprising;

a substrate including a first portion and a second portion,

at least one micro-object disposed on the first portion of said substrate, and

a diffractive structure disposed on the second portion of said substrate,

wherein at least one magnified visual representation of said micro-objects is observed when said optically variable device is observed from a predetermined relative observation point from and said micro-object is disposed between said diffractive structure and said observation point.

13. The article of claim 12 wherein said substrate comprises a generally planar member including a first side and a second side;

wherein the first side is intermediate the second side and said observation point; and

wherein the second side is distal from said observation point.

14. The article of claim 13 wherein the first and second portions of said substrate are both at or about the second side of said substrate.

15. The article of claim 13 wherein the first portion of said substrate is at or about the first side of the substrate;

and wherein the second portion of the substrate is at or about the second side of said substrate.

16. The article of claim 12 wherein said at least one micro-object comprises a plurality of micro-objects selectively organized in an object layer;

wherein said diffractive structure comprises a plurality of diffractive elements selectively organized into a diffractive layer; and

wherein said diffractive elements of said diffractive layer diffract light at different wavelengths depending upon the predetermined relative observation point from which said optically variable device is viewed.

17. The article of claim 12 wherein in addition to said at least one magnified visual representation of said micro-object, said diffractive elements impart at least one additional predetermined optical effect selected from the group consisting of a change in observed color, enhanced contrast between said at least one magnified visual representation of said micro-object and background, a movement or animation of said at least one magnified visual representation of said micro-object, a change in the size or shape of said magnified visual representation, and a transformation of said magnified visual representation into a different object or optical effect.

18. A method of creating a security device having at least one optically variable device with diffraction-based micro-optics, the method comprising:

originating a master of said optically variable device, said master including a diffractive structure;

generating an object layer including at least one micro-object;

replicating said master; and

converting said master into final form to provide said optically variable device;

wherein said converting step includes combining said, object layer and said diffractive grating structure on a first portion and a second portion, respectively, of a substrate; and

wherein at least one magnified visual representation of said micro-object is observed when said optically variable device is observed from a predetermined relative observation point and said micro-object is disposed between said diffractive structure and said observation point.

19. The method of claim 18 wherein said step of originating said master further comprises:

designing said diffractive structure, and

interfacing with equipment structured to make said diffractive structure.

20. The method of claim 19 further comprising:

employing at least one of electron beam lithography and holography to make said diffractive structure, combining a number of elements of said master, and electroforming said master.

21. The method of claim 18 wherein said step of replication further comprises:

providing substrate and reproducing said master by a mass reproduction method selected from the group consisting of embossing into a thermoplastic film using applied heat and pressure, casting liquid resin onto the grating structure and curing said resin to create a film, and injection molding.

22. The method of claim 18 further comprising:

creating said at least one micro-object integrally with said diffractive structure.

23. The method of claim 18 wherein said converting step further comprises:

providing at least one additional layer selected from the group consisting of a metallic layer, a transparent refractive layer, a reflective layer, a protective layer, and an additional substrate.

24. The method of claim 18 wherein said step of converting further comprises:

converting said optically variable device to final form, said final form being selected from the group consisting of label, laminate, thread, and transfer film.

25. The method of claim 18 further comprising:

providing an article,

incorporating said security device into a transfer medium, and

transferring said security device onto said article.

26. The method of claim 18 further comprising:

providing an article, and

incorporating said security device directly into or onto said article.

27. The method of claim 18 wherein at least some of the steps of said method are computer automated.