Methods of manufacturing security documents and security devices

Patent metadata

Field	Value
Publication number	US-10438309-B2
Application number	US-201615740620-A
Country	US
Kind code	B2
Filing date	Jul 11, 2016
Priority date	Jul 10, 2015
Publication date	Oct 8, 2019
Grant date	Oct 8, 2019

Abstract

A method of making a security device including: (a) forming an array of focussing elements on at least a first region of a focussing element support layer, by: (a)(i) applying a first transparent curable material either to the focussing element support layer or to a casting tool carrying a surface relief corresponding to the focussing elements, over an first sub-region of the first region and applying a second transparent curable material to a second sub-region of the first region laterally offset from the first sub-region, the first and second transparent curable materials having different optical detection characteristics from one another; (a)(ii) forming the first and second transparent curable materials with the casting tool; and (a)(iii) curing the first and second transparent curable materials in the first region, so as to retain the surface relief.

First claim

The invention claimed is:

1. A method of making a security device, comprising:
(a) forming an array of focussing elements across at least a first region of a focussing element support layer, by:
(a)(i) applying a first transparent curable material either to the focussing element support layer or to a casting tool carrying a surface relief corresponding to the focussing elements, over an first sub-region of the first region and applying a second transparent curable material to a second sub-region of the first region laterally offset from the first sub-region, the first and second transparent curable materials having different optical detection characteristics from one another;
(a)(ii) forming the first and second transparent curable materials with the casting tool; and
(a)(iii) curing the first and second transparent curable materials in the first region, so as to retain the surface relief corresponding to the focussing elements in the first sub-region and in the second sub-region;

wherein the first and second transparent curable materials are applied to the focussing element support layer or to the casting tool only over the area corresponding to that of the respective sub-regions and the casting tool carries the surface relief over an area extending beyond that of the first region.

2. A method of making a security device according to claim 1 , wherein the first and second sub-regions are spaced from one another.

3. A method of making a security device according to claim 1 , wherein the first and second sub-regions abut one another.

4. A method of making a security device according to claim 1 , wherein the first and second sub-regions individually or collectively define one or more indicia.

5. A method of making a security device according to claim 1 , wherein the different optical detection characteristics are any of: different visible colours, different fluorescence, different luminescence or different phosphorescence.

6. A method of making a security device according to claim 1 , further comprising:
(b) providing an image array located in a plane spaced from the array of focussing elements by a distance substantially equal to the focal length of the focussing elements whereby the focussing elements exhibit a substantially focussed image of the image array.

7. A method of making a security device according to claim 1 , wherein the casting tool carries the surface relief over an area extending over substantially the whole area of the casting tool.

8. A method of making a security document, comprising:
providing a polymer substrate having a first and a second surface;
forming a security device thereon using the method of claim 1 , wherein either the focussing element support layer comprises the polymer substrate or step (a) further comprises applying the focussing element support layer to the first surface of the polymer substrate, at least across the first region; and
applying at least one opacifying layer to the first and/or second surfaces of the polymer substrate, the or each opacifying layer comprising a non-transparent material, wherein at least the opacifying layer(s) on the first surface of the substrate define a gap forming a window region in which at least part of each of the first sub-region and the second sub-region is disposed.

Assignees

• De La Rue Int Ltd

Inventors

• Holmes Brian William
• Godfrey John

Classifications

• G06T1/0014 Primary

  Image feed-back for automatic industrial control, e.g. robot with camera (robots B25J19/023) · CPC title

• B29D11/00298 Primary

  Producing lens arrays · CPC title

• H04N23/67

  Focus control based on electronic image sensor signals · CPC title

• H04N23/90

  Arrangement of cameras or camera modules, e.g. multiple cameras in TV studios or sports stadiums · CPC title

• B42D25/425

  by deformation, e.g. embossing · CPC title