Security device

Abstract

A security device includes a transparent, coloured element in a first region of the device and in a surface of which a first optically variable effect generating relief structure is formed. A reflection enhancing layer extends over the first optically variable effect generating relief microstructure and follows the contour of the relief, the reflection enhancing layer also being provided in a second region of the device laterally offset from the first region.

1 .- 35 . (canceled) 
     
     
         36 . A security device comprising a transparent, coloured element in a first region of the device and in a surface of which a first optically variable effect generating relief structure is formed; and a reflection enhancing layer extending over the first optically variable effect generating relief microstructure and following the contour of the relief, the reflection enhancing layer also being provided in a second region of the device laterally offset from the first region. 
     
     
         37 . A device according to  claim 36 , wherein the reflection enhancing layer extends continuously from the first region to the second region. 
     
     
         38 . A device according to  claim 36 , wherein the reflection enhancing layer is provided in discrete portions in the first region and second region respectively. 
     
     
         39 . A device according to  claim 36 , wherein the second region surrounds the first region. 
     
     
         40 . A device according to  claim 36 , wherein the second region includes a second, transparent coloured element having a colour different from the colour of the first transparent coloured element, a surface of the second transparent, coloured element being provided with a second optically variable effect generating relief microstructure, the reflection enhancing layer extending over the second optically variable effect generating relief microstructure and following the contour of the relief. 
     
     
         41 . A device according to  claim 40 , wherein the first and second optically variable effect generating relief microstructures are different. 
     
     
         42 . A device according to  claim 36 , wherein the reflection enhancing layer is one of a metal layer or high refractive index layer. 
     
     
         43 . A device according to  claim 36 , wherein one or more parts of the reflection enhancing layer are formed as one or more symbols, characters, alphanumeric figures or other graphical shapes. 
     
     
         44 . A device according to  claim 40 , wherein the first and second elements have different shapes. 
     
     
         45 . A device according to  claim 36 , further comprising an adhesive layer, for example a photosensitive or heat sensitive adhesive layer, over the transparent substrate. 
     
     
         46 . A device according to  claim 36 , wherein the or each optically variable effect generating surface relief microstructure comprises one or more of a hologram, diffraction grating, prismatic structure, and microlens array. 
     
     
         47 . A stripe assembly having a sequence of security devices according to  claim 36  spaced along a support, with the colours of successive transparent coloured elements in the first regions being different. 
     
     
         48 . A transfer structure comprising a security device according to  claim 36 , supported on a carrier via a release layer and having an adhesive on its surface furthest from the carrier. 
     
     
         49 . A method of manufacturing a security device, the method comprising providing a curable material on a carrier to define a transparent, coloured element in a first region; forming a surface of the element with an optically variable effect surface relief microstructure; curing the material so that the microstructure is retained by the cured material; and providing a reflection enhancing layer extending over the first optically variable effect surface relief microstructure following the contour of the relief, the reflection enhancing layer also being provided in a second region laterally offset from the first region. 
     
     
         50 . A method according to  claim 49 , wherein the reflection enhancing layer extends continuously from the first region to the second region. 
     
     
         51 . A method according to  claim 49 , wherein the reflection enhancing layer is provided in discrete portions in the first and second regions respectively. 
     
     
         52 . A method according to  claim 49 , wherein the second region surrounds the first region. 
     
     
         53 . A method according to  claim 49 , further comprising providing a second, transparent coloured element in the second region on the carrier, the second element having a colour different from the colour of the first transparent, coloured element, providing a surface of the second transparent, coloured element with a second optically variable effect generating relief microstructure, and wherein the reflection enhancing layer is provided over the second, transparent coloured element following the contour of the relief. 
     
     
         54 . A method according to  claim 53 , wherein the first and second optically variable effect generating relief structures are different. 
     
     
         55 . A method according to  claim 49 , wherein the reflection enhancing layer comprises a metal or high refractive index layer. 
     
     
         56 . A method according to  claim 49 , wherein the optically variable effect generating relief microstructures are cast or embossed into the curable materials. 
     
     
         57 . A method according to  claim 49 , wherein the or each element of curable material is printed onto the carrier. 
     
     
         58 . A method according to  claim 49 , wherein the reflection enhancing layer is provided over both the cured regions and areas where there is no cured or curable material. 
     
     
         59 . A method according to  claim 49 , wherein the reflection enhancing layer is vacuum deposited or printed. 
     
     
         60 . A method according to  claim 49 , wherein the reflection enhancing layer is printed using a metallic ink including one or more colourants. 
     
     
         61 . A method according to  claim 49 , further comprising forming parts of the reflection enhancing layer as one or more symbols, characters, alphanumeric figures or other graphical shapes. 
     
     
         62 . A method according to  claim 61 , wherein the forming step comprises selectively demetallising a metallic layer. 
     
     
         63 . A method according to  claim 49 , further comprising providing an adhesive layer, for example a photosensitive or heat sensitive adhesive layer, over the cured material and after the provision of the reflection enhancing layer. 
     
     
         64 . A method according to  claim 49 , wherein the or each optically variable effect generating relief microstructure comprises one or more of a hologram, diffraction grating, prismatic structure, and microlens array. 
     
     
         65 . A security device manufactured according to  claim 49 . 
     
     
         66 . A security device according to  claim 65 , the device comprising a label or stripe. 
     
     
         67 . A method of transferring a security device on a carrier web manufactured according to  claim 49  onto an article to which it is secured by adhesive, the method comprising hot stamping the security device onto the article with a heat sensitive adhesive between the security device and the article. 
     
     
         68 . An article provided with a security device according to  claim 36 . 
     
     
         69 . An article according to  claim 68 , wherein the article is a security article such as a security document, for example one of banknotes, cheques, passports, identity cards, certificates of authenticity, fiscal stamps and other documents for securing value or personal identity. 
     
     
         70 . A security device according to  claim 36 , wherein the metallic layer is a metal such as aluminium, copper or gold.