Methods of manufacturing security documents and security devices

Patent metadata

Field	Value
Publication number	US-10861121-B2
Application number	US-201615740172-A
Country	US
Kind code	B2
Filing date	Jul 11, 2016
Priority date	Jul 10, 2015
Publication date	Dec 8, 2020
Grant date	Dec 8, 2020

Abstract

A method of manufacturing a security document, including: providing a polymer substrate having first and second surfaces; and: applying an array of focussing elements to the first surface of the polymer substrate across a first region; forming an image array by: providing a die form having a surface including an arrangement of raised areas and recessed areas defining the pattern; applying a first curable material to the surface of the die form so it substantially fills the recessed areas; bringing a pattern support layer in contact with the surface of the die form so it covers the recessed areas; separating the pattern support layer from the surface of the die form so the first curable material in the recessed areas is removed from the recessed areas and retained on the pattern support layer; and at least partly curing the first curable material in one or more curing steps.

First claim

The invention claimed is:

1. A method of manufacturing a security device, comprising:
providing a transparent support layer having first and second surfaces;
conveying the transparent support layer along a transport path in a machine direction; and during the conveying, simultaneously at the same position along the transport path in the machine direction:
(a) forming an array of focussing elements on the first surface of the transparent support layer in at least a first region by:
(a)(i) applying at least one transparent curable material either to the transparent support layer or to a casting tool, carrying a surface relief corresponding to the focussing elements, over an area which includes at least the first region;
(a)(ii) forming the at least one transparent curable material with the casting tool; and
(a)(iii) curing the at least one transparent curable material so as to retain the surface relief in the first region; and

(b) applying an image array to the second surface of the transparent support layer in at least part of the first region by printing the image array onto the transparent support layer via one of: intaglio printing, gravure printing, wet lithographic printing, dry lithographic printing, or flexographic printing;

wherein the array of focussing elements and the image array are registered to one another at least in the machine direction.

2. The method according to claim 1 , wherein:
in step (a), a focussing element cylinder carrying the surface relief on its circumference corresponding to the array of focussing elements is used as the casting tool to form the array of focussing elements on the first surface of the transparent support layer,
in step (b), an image cylinder is used to apply the image array to the second surface of the transparent support layer,
steps (a) and (b) are performed simultaneously at a nip formed between the focussing element cylinder and the image cylinder, and
the transparent support layer passes through the nip.

3. The method according to claim 2 , wherein:
the transport path is configured such that the transparent support layer is held in contact with the focussing element cylinder over a portion of its circumference between a first contact point and a last contact point spaced from one another by a non-zero distance, and
the nip formed between the focussing element cylinder and the image cylinder either is located between the first and last contact points, closer along the transport path to the last contact point than to the first contact point, or forms the last contact point.

4. The method according to claim 1 , wherein:
a focussing element cylinder constitutes the casting tool, and
step (a)(iii) is performed while the transparent support layer is held in contact with the focussing element cylinder over the portion of its circumference such that the at least one transparent curable material is at least partly cured at a location of a nip formed between the focussing element cylinder and an image cylinder used to apply the image array to the second surface of the transparent support layer.

5. A method of manufacturing a security document, comprising:
providing a polymer substrate having first and second surfaces in the form of a web;
applying at least one opacifying layer to the first and/or second surfaces of the polymer substrate in the form of a web, the or each opacifying layer comprising a non-transparent material; and
then cutting the web into sheets in the direction of web transit,
then performing on the sheets, in at least one sheet-fed process:
(a) applying an array of focussing elements to the first surface of the polymer substrate across a first region by:
(a)(i) applying at least one transparent material either to the polymer substrate or to a casting tool carrying a surface relief corresponding to the focussing elements, over an area that includes at least the first region;
(a)(ii) forming the at least one transparent curable material with the casting tool; and
(a)(iii) curing the at least one transparent curable material so as to retain the surface relief in the first region; and

(b) applying an image array to the polymer substrate in the first region, such that the image array is located in a plane spaced from the array of focussing elements by a distance substantially equal to the focal length of the focussing elements via one of: intaglio printing, gravure printing, wet lithographic printing, dry lithographic printing, or flexographic printing, wherein:

the focussing elements exhibit a substantially focussed image of the image array; and
either the image array is located between the array of focussing elements and the at least one opacifying layer on the first surface of the substrate, or 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 the array of focussing elements is disposed such that a substantially focussed image of at least part of the image array is displayed in the window region.

6. The method according to claim 5 , further comprising, after cutting the web into sheets:
printing a graphics layer onto the at least one opacifying layer on the first and/or second surfaces of the polymer substrate in at least one sheet-fed process.

7. The method according to claim 5 , wherein:
in step (b) the image array is provided on the first surface of the polymer substrate, and
the focussing element array includes an optical spacing portion.

8. A method of manufacturing a security document, comprising:
providing a polymer substrate having first and second surfaces in the form of a web; and in either order:
(i) applying at least one opacifying layer to the first and/or second surfaces of the polymer substrate in the form of a web, the or each opacifying layer comprising a non-transparent material; and
(ii) applying an array of focussing elements to the first surface of the polymer substrate in the form of a web across a first region by:
applying at least one transparent curable material either to the polymer substrate or to a casting tool carrying a surface relief corresponding to the focussing elements, over an area that includes at least the first region;
forming the at least one transparent curable material with the casting tool; and
curing the at least one transparent curable material so as to retain the surface relief in the first region; and then after steps (i) and (ii):

cutting the web into sheets in the direction of web transit;
then performing on the sheets, in at least one sheet-fed process:
applying an image array to the polymer substrate in the first region, such that the image array is located in a plane spaced from the array of focussing elements by a distance substantially equal to the focal length of the focussing elements via one of: intaglio printing, gravure printing, wet lithographic printing, dry lithographic printing, or flexographic printing;

wherein:
the focussing elements exhibit a substantially focussed image of the image array; and
either the image array is located between the array of focussing elements and the at least one opacifying layer on the first surface of the substrate, or 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 the array of focussing elements is disposed such that a substantially focussed image of at least part of the image array is displayed in the window region.

9. The method according to claim 8 , further comprising, after cutting the web into sheets:
printing a graphics layer onto the at least one opacifying layer on the first and/or second surfaces of the polymer substrate in at least one sheet-fed

Assignees

• De La Rue Int Ltd

Inventors

• Holmes Brian William
• Godfrey John
• Cornes Ian
• O'Malley John
• Commander Lawrence George

Classifications

• G06T1/0014 Primary

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• 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

• B42D25/342

  Moiré effects · CPC title