Security elements, and methods and apparatus for their manufacture

Patent metadata

Field	Value
Publication number	US-9649871-B2
Application number	US-201514971443-A
Country	US
Kind code	B2
Filing date	Dec 16, 2015
Priority date	Feb 1, 2010
Publication date	May 16, 2017
Grant date	May 16, 2017

Abstract

An apparatus is provided for magnetically imprinting indicia into a layer on an article, the layer comprising a composition in which magnetic or magnetisable particles are suspended. The apparatus comprises: a soft magnetisable sheet, having an outer surface arranged to face the article in use, and an opposing interior surface; and a permanent magnet, shaped such that its magnetic field contains perturbations giving rise to indicia. The permanent magnet is disposed adjacent the interior surface of the soft magnetisable sheet. The soft magnetisable sheet enhances the perturbations of the magnetic field of the permanent magnet such that when the layer to be imprinted is located adjacent the outer surface of the soft magnetisable sheet, the magnetic or magnetisable particles are oriented by the magnetic field to display the indicia.

First claim

The invention claimed is:

1. A security element comprising a layer disposed on a substrate, the layer comprising a composition having magnetic or magnetisable particles therein, each particle having at least one substantially planar surface,
wherein the magnetic or magnetisable particles vary in orientation across the layer such that:
at a first part of the layer, the particles are orientated with their planar surfaces substantially parallel to the normal to the layer, the angle between the planar surfaces of the particles and the normal gradually increasing with increasing distance from the first part to a maximum of approximately 90 degrees at a first position of the layer before decreasing gradually again until a second, father, position of the layer, the normals to the planar surfaces of the particles disposed between the first part and the second position intersecting one another at points on a first side of the layer, and
from the second position, the angle between the planar surfaces of the particles and the normal of the layer gradually increases with increasing distance, the normals to the planar surfaces of the particles intersecting one another at points on a second side of the layer, opposite to the first side,
such that the security element displays a bright edge corresponding to the first position, between a first dark area which includes the first part of the layer, and a second dark area, at least when the security element is viewed along a direction substantially normal to the plane of the substrate, and
wherein when viewed under daylight, the thickness of the bright edge between the contrasting dark areas is less than about 10 mm.

2. A security element according to claim 1 , wherein the lateral distance between the first part of the layer and the second position is between 1 and 10 mm.

3. A security element according to claim 1 , wherein the rate of change of particle angle with lateral distance is greater between the first part of the layer and the first position, and between the first position and the second positions, than outside the second position.

4. A security element according to claim 1 wherein, in the region of increasing angle between the planar surfaces of the particles and the normal to the layer outside the second position, the angle does not increase to substantially 90 degrees within the periphery of the layer.

5. A security element according to claim 1 , wherein in the region of increasing angle between the planar surfaces of the particles and the normal to the layer outside the second position, the angle does not increase to substantially 90 degrees within at least 2 mm of the second position.

6. A security element according to claim 1 , wherein the angle between the planar surfaces of the particles and the normal to the layer decreases to an angle of less than 45 degrees at the second position.

7. A security element according to claim 1 , wherein the variation of the particles' orientation is substantially the same along each direction such that the bright edge forms a circular outline, the first dark area being located within the outline and the second dark area being located outside the outline.

8. A security element according to claim 1 , wherein the variation of the particles' orientation along each direction is a function of angular position, such that the bright edge forms a non-circular outline, the first dark area being located within the outline and the second dark area being located outside the outline.

9. A security element according to claim 1 , wherein along selected direction(s) the particle orientation does not undergo any variation, remaining substantially parallel to the normal of the substrate, to thereby form one or more corresponding gaps in the bright edge.

10. A security element according to claim 1 , wherein when the angle of viewing is changed, the bright edge appears to move laterally, relative to the layer.

11. A security element according to claim 1 , wherein the layer is provided with one or more registration features against which the position of the bright edge may be judged.

12. A security element according to claim 1 , wherein the magnetic or magnetisable particles have an elongate shape.

13. A security element according to claim 1 , wherein the magnetic or magnetisable particles comprise an optically variable structure whereby the particles reflect light having wavelengths within a first spectral band at a first angle of incidence, and light having wavelengths within a second, different spectral band at a second angle of incidence.

14. A security element according to claim 13 , wherein a region of the layer outside the second radial position exhibits, at certain viewing angles, a first portion of a first color and a second portion of a second color, the boundary between the first and second portions appearing to move as the viewing angle is altered.

15. A security element according to claim 1 , wherein, when viewed under multiple light sources, multiple bright edges of matching shape, displaced from one another, are displayed.

16. An insert for a security document comprising a security element according to claim 1 .

17. A transfer element comprising a security element according to claim 1 , disposed on a support substrate.

18. A transfer element according to claim 17 , further comprising an adhesive layer for adhering the security element to an article.

19. A transfer element according to claim 17 , further comprising a release layer between the security element and the support substrate.

20. A transfer element according to claim 17 , wherein the transfer element is a thread, tape, foil or patch.

21. A document of value comprising a security element according to claim 1 .

Assignees

• De La Rue Int Ltd

Inventors

• Bargir Sameer Mohammed
• Howland Paul

Classifications

• B41M3/14 Primary

  Security printing {(securities B42D25/29)} · CPC title

• B41F11/02 Primary

  for securities (security printing B41M3/14) · CPC title

• B42D25/00

  Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof (printing processes to produce identification or security features B41M3/14) · CPC title

• Y10T428/24

  Structurally defined web or sheet [e.g., overall dimension, etc.] · CPC title

• B42D25/355

  Security threads · CPC title