Methods of manufacturing image element arrays for security devices

Patent metadata

Field	Value
Publication number	US-10300730-B2
Application number	US-201615770031-A
Country	US
Kind code	B2
Filing date	Nov 7, 2016
Priority date	Nov 13, 2015
Publication date	May 28, 2019
Grant date	May 28, 2019

Abstract

A method of manufacturing an image element array includes: providing a production tool having a surface pattern of ink-receptive elements spaced by areas which are not, the ink-receptive elements defining the array image elements; applying a multi-colored first image formed of a inks to only the ink-receptive elements; and transferring only the portions of the multi-colored first image corresponding to the image elements from the production tool to a substrate. An image element array is formed on the substrate. The production tool surface pattern is configured such that when viewing and image element arrays overlap, each viewing element within an image element array first region directs light from a respective image element or from a respective gap. The viewing angle in the first region directs light from either the array or the gaps.

First claim

The invention claimed is:

1. A method of manufacturing an image element array for an optically variable security device, comprising:
providing a production tool having a surface pattern of ink-receptive elements spaced by areas which are not ink-receptive, the ink-receptive elements defining image elements of the desired image element array;
applying a multi-coloured first image formed of a plurality of inks to only the ink-receptive elements of the surface pattern and not to the areas in between;
transferring only portions of the multi-coloured first image corresponding to the image elements of the desired image element array from the production tool to a substrate, by bringing the plurality of inks on the surface pattern into contact with the substrate or with a transfer assembly which then contacts the substrate, whereby an image element array is formed on the substrate;
wherein the surface pattern on the production tool is configured such that, when a viewing element array is overlapped with the image element array, each viewing element within a first region of the image element array directs light from a respective one of the image elements or from a respective one of gaps between the image elements in dependence on a viewing angle, whereby depending on the viewing angle the viewing element array in the first region directs light from either the array of image elements or from the gaps therebetween, such that upon changing the viewing angle, the first image is displayed by the image elements across the first region of the image element array at a first range of viewing angles and not at a second range of viewing angles, and
wherein the surface pattern comprises either:
a surface relief structure of elevations and depressions, the elevations forming the ink-receptive elements and the depressions forming the areas which are not ink-receptive; or
an arrangement of hydrophilic and hydrophobic parts of the surface of the production tool, the hydrophobic parts forming the ink-receptive elements and the hydrophilic parts forming the areas which are not ink-receptive.

2. A method according to claim 1 , wherein each of the plurality of inks is applied to the surface pattern in accordance with a respective image component representing at least one area of the first image having a colour to which the ink contributes, at least two of the image components corresponding to different areas of the first image such that at least two of the plurality of inks are applied to different respective areas of the surface pattern.

3. A method according to claim 1 , wherein at least some of the ink-receptive elements individually receive two or more of the plurality of inks in respective laterally offset areas of the element, whereby at least some of the image elements in the image element array formed on the substrate are individually multi-coloured.

4. A method according to claim 1 , wherein the multi-coloured first image is applied to the surface pattern by either:
applying each of the plurality of inks to the production tool sequentially, in register with one another; or
applying each of the plurality of inks to a collection surface in register with one another and then transferring the plurality of inks simultaneously from the collection surface onto the surface pattern.

5. A method according to claim 1 , wherein each of the plurality of inks is applied from a respective patterned tool being a patterned lithographic printing plate, a patterned chablon plate, a patterned anilox roller, or a patterned gravure roller.

6. A method according to claim 1 , wherein in the first region of the image element array, the surface pattern is configured such that the image elements have a same width as one another and are arranged periodically at least in a direction parallel to the width of each of the elements.

7. A method according to claim 1 , wherein in the first region of the image element array, the surface pattern is configured either
such that the image elements are elongate image elements; or
such that the image elements are arranged in a periodic two-dimensional grid.

8. A method according to claim 1 , wherein the surface pattern is configured such that the image elements are 100 microns or less in at least one dimension.

9. A method according to claim 1 , further comprising providing a second image overlapping at least part of the image element array such that elements of the second image are exposed through the gaps between the elements of the first image, whereby the elements of both images can be viewed from a same side of the image array.

10. An image element array manufactured in accordance with claim 1 .

11. A method of manufacturing a security device, comprising:
(i) manufacturing an image element array using the method of claim 1 ; and
(ii) providing a viewing element array overlapping the image element array;
wherein the image element array and viewing element array are configured to co-operate such that each viewing element within a first region of the image element array directs light from a respective one of the image elements or from a respective one of the gaps between the image elements in dependence on the viewing angle, whereby depending on the viewing angle the viewing element array in the first region directs light from either the array of image elements or from the gaps therebetween, such that upon changing the viewing angle, the first image is displayed by the image elements across the first region of the image element array at a first range of viewing angles and not at a second range of viewing angles.

12. A method according to claim 11 ,
wherein in the first region of the image element array, the surface pattern is configured such that the image elements have a same width as one another and are arranged periodically at least in a direction parallel to the width of each of the elements, and
wherein at least in the first region, the viewing element array is periodic in at least one dimension.

13. A method according to claim 11 , wherein the viewing element array is registered to the image element array at least in terms of orientation.

14. A method according to claim 11 , wherein the viewing element array is a focusing element array, the focusing elements comprising lenses or mirrors.

15. A security device manufactured in accordance with claim 11 .

16. A security article comprising a security device according to claim 15 , wherein the security article is a security thread, strip, foil, insert, transfer element, label, or patch.

17. A security document comprising a security device according to claim 15 , wherein the security document is a banknote, check, passport, identity card, driver's license, certificate of authenticity, fiscal stamp, or other document for securing value or personal identity.

18. A method of manufacturing an image element array for an optically variable security device, comprising:
providing a production tool having a surface pattern of ink-receptive elements spaced by areas which are not ink-receptive, the ink-receptive elements defining the image elements of the desired image element array;
applying a multi-coloured first image formed of a plurality of inks to only the ink-receptive elements of the surface pattern and not to the areas in between;
transferring only portions of the multi-coloured first image corresponding to the image elements of the desired image element array from the production tool to a substrate, by bringing the plurality of inks on the surface pattern into contact with the substrate or with a transfe

Assignees

• De La Rue Int Ltd

Inventors

• Godfrey John
• Lister Adam

Classifications

• B42D25/45

  Associating two or more layers · CPC title

• B42D25/351

  Translucent or partly translucent parts, e.g. windows · CPC title

• B42D25/48

  Controlling the manufacturing process · CPC title

• B42D25/324 Primary

  Reliefs · CPC title

• B42D25/23

  Identity cards · CPC title