Radiation curable embossed ink security devices for security documents
A security document and a method of manufacturing a security document are provided in which a radiation curable ink is applied to at least one side of a substrate including at least one region of transparent plastics material forming a window or half-window area. The ink is embossed while soft and cured with radiation to form an embossed security device within the window or half-window area including one or more of a diffractive structure, a lens structure or other security element having a relief structure.
1. A security document comprising a substrate including at least one region of transparent or translucent plastics material forming a window or half-window area, and a security device integrated into the window or half-window area, wherein the security device comprises a composite security device formed from a continuous layer of embossed radiation curable ink containing first and second different embossed security elements in different regions of the embossed radiation curable ink on the same side of the substrate, wherein each of said first and second security elements corresponds entirely to a respective embossed region of the radiation curable ink, wherein the second security element is located within 0.3 mm of the first security element, and wherein the first security element comprises a diffractive structure, and the second security element comprises a lens structure or other non-diffractive security element having an embossed relief structure.
2. The security document according to claim 1 , wherein the security device includes a verification means for verifying another security feature provided on the document.
3. The security document according to claim 2 , wherein the verification means includes a lens, a lenticular array or an array of microlenses.
4. The security document according to claim 1 , wherein the composite security device includes an inspectable security element and a verification means for verifying another security feature on the document.
5. The security document according to claim 1 , wherein the document is a banknote.
6. The security document according to claim 1 , wherein the security device is integrated into a half-window area of the substrate.
7. The security document according to claim 1 , wherein the second security element is located within 0.1 mm of the first security element.
8. The security document according to claim 1 , wherein the security device includes a light transmissive security element.
9. The security document according to claim 8 , wherein the security device is formed from an embossed transparent ink.
10. A method of manufacturing a security document comprising the steps of:
providing a substrate including at least one region of transparent plastics material forming a window or half-window area;
applying a radiation curable ink directly to at least one surface of the substrate in at least the window or half-window area; and
simultaneously embossing the ink and curing with radiation to form a security device within the window or half-window area, wherein the embossed ink forms a composite security device containing first and second different security elements in different regions of the embossed ink on the same side of the substrate, wherein the first security element comprises a diffractive structure, and the second security element comprises a lens structure or other non-diffractive relief structure.
11. A method according to claim 10 , wherein at least one opacifying layer is applied to at least one side of a transparent polymeric substrate with the at least one opacifying layer omitted in the region forming the window or half window area.
12. A method according to claim 11 , wherein opacifying layers are applied to opposite sides of the substrate with the opacifying layers on both sides of the substrate omitted in one region to form a transparent window in the security document.
13. The method according to claim 10 , wherein the radiation curable ink is applied in a window area of the substrate.
14. The method according to claim 10 , wherein the radiation curable ink is applied in a half-window area of the substrate.
15. The method according to claim 10 , wherein the radiation curable ink is a transparent ink or lacquer formed from a clear resin material.
16. The method according to claim 10 , wherein the radiation curable ink is applied in a Gravure printing process.
17. The method according to claim 10 , wherein the radiation curable ink is a metallic ink composition applied in a layer which is sufficiently thin to allow the transmission of light.