Security element and security document

Patent metadata

Field	Value
Publication number	US-10112430-B2
Application number	US-201314424678-A
Country	US
Kind code	B2
Filing date	Sep 3, 2013
Priority date	Sep 3, 2012
Publication date	Oct 30, 2018
Grant date	Oct 30, 2018

Abstract

The invention relates to a security element (2) with a first area (30) that is transparent in transmitted light. The security element (2) has a substrate (21) which has, in the first area (30), one or more transmissive diffraction structures which display one or more optical security features when observed in transmitted light.

First claim

The invention claimed is:

1. A security element comprising a multi-layer film body, with a first area that is transparent in transmitted light,
wherein the security element has a substrate which has, in the first area, one or more transmissive diffraction structures which display one or more optical security features when observed in transmitted light, and
wherein, in the first area, two or more different transmissive diffraction structures are arranged which, when observed in transmitted light against a light source radiating white light, display different color-change effects when the security element is tilted and/or turned, and
wherein, when a first side of the security element facing an observer is observed in transmitted light, against a light source which radiates white light parallel to a beam axis and is arranged on a second side of the security element opposite the first side of the security element, at least one of the one or more transmissive diffraction structures brings about a change in a color of a partial area of the first area which is covered with the one or more transmissive diffraction structures when the security element is tilted relative to the beam axis, wherein the partial area is patterned in the form of a motif, and
wherein the at least one transmissive diffraction structure comprises a relief structure formed in the first area, the relief structure having a relief depth of between 400 nm and 1700 nm and a grating period of between 500 nm and 1500 nm such that light incident on the second side of the security element in a beam direction perpendicular to a plane spanned by the second side of the security element is transmitted in the direction of the beam direction through the substrate largely unchanged in its color spectrum, wherein a change of the spectrum in the range of from 460 nm to 660 nm is less than 15%.

2. A security element according to claim 1 , wherein the one or more transmissive diffraction structures are designed such that, when observed in transmitted light against a light source radiating white light directionally, partial areas of the first area that are covered with the one or more transmissive diffraction structures display, as an optical security feature, a color-change effect that is recognizable to a human observer, when the security element is tilted.

3. A security element according to claim 1 , wherein a transmissivity of the at least one transmissive diffraction structure and/or of the security element in the beam direction is greater than 70%.

4. A security element according to claim 1 , wherein the at least one transmissive diffraction structure transmits light incident on the second side in a beam direction with an angular offset of from 20° to 50° relative to a surface normal of a plane spanned by the second side of the security element changed in its color spectrum in a direction perpendicular to the surface normal of the plane spanned by the second side of the security element or in the beam direction.

5. A security element according to claim 1 , wherein the first area has one or more first zones which are covered with a first of the transmissive diffraction structures, and has one or more second zones which are covered with a second of the transmissive diffraction structures, wherein the first transmissive diffraction structure differs from the second transmissive diffraction structure.

6. A security element according to claim 5 , wherein the first and second transmissive diffraction structures differ in their relief depth, their azimuth angle and/or their grating period.

7. A security element according to claim 5 , wherein the first and second transmissive diffraction structures are formed of different types of transmissive diffraction structures.

8. A security element according to claim 5 , wherein neighboring first and second zones are spaced apart from each other by less than 10 μm.

9. A security element according to claim 5 , wherein each of the first and second zones has a lateral dimension of more than 300 μm.

10. A security element according to claim 9 , wherein the one or more first and second zones are molded to form a motif, wherein the first zones form a foreground area of the motif and the second zones form a background area of the motif, or wherein the one or more first zones are molded to form a first motif and the one or more second zones are molded to form a second motif.

11. A security element according to claim 5 , wherein, in the first area a plurality of first zones and second zones are provided, and wherein each of the first and second zones has at least one lateral dimension of less than 300 μm.

12. A security element according to claim 5 , wherein, in the first area, a plurality of third zones which are covered with a third one of the transmissive diffraction structures, and/or fourth zones which are covered with a fourth one of the transmissive diffraction structures are provided, wherein each of the first, second, third and fourth transmissive diffraction structures mutually differ from each other and each of the third and fourth zones respectively has at least one lateral dimension of less than 300 μm.

13. A security element according to claim 11 , wherein the first area has a motif area which is divided into a plurality of image point areas, wherein, in at least a first of the image point areas at least two different zones selected from the group first and second zones, the group first, second and third zones or the group first, second, third and fourth zones are arranged and wherein a color appearing in the first image point area when observed in transmitted light at least at one tilt angle is generated by additive color mixing of colors generated at this tilt angle by those of the transmissive diffraction structures arranged in this image point area in the different zones.

14. A security element according to claim 13 , wherein at least 10% of the image point areas are formed as first image point areas.

15. A security element according to claim 11 , wherein a first motif area molded in the form of a first motif and a second motif area molded in the form of a second motif are provided in the first area, wherein the first motif area is divided into a plurality of partial areas, wherein each of the partial areas are covered with one or more first zones, and the second motif area is divided into a plurality of partial areas, wherein each of the partial areas are covered with one or more second zones.

16. A security element according to claim 15 , wherein each of the first and second zones is arranged according to a 1- or 2-dimensional grid and the first and second zones are gridded into each other in the overlap area.

17. A security element according to claim 1 , wherein the substrate has, in the first area, one or more reflective diffraction structures which display one or more optical security features when observed in reflected light.

18. A security element according to claim 1 , wherein one or more of the one or more transmissive diffraction structures are formed of a relief structure molded in a surface of the substrate, which are molded in the surface of the first side of the security element.

19. A security element according to claim 1 , wherein one or more of the one or more transmissive diffraction structures are formed of a relief structure molded between two transparent layers of the substrate, wherein a refractive index of these layers differs by at least 0.1.

20. A security element according to claim 19 , wherein one of the two transpar

Assignees

• Ovd Kinegram Ag

Inventors

• Tompkin Wayne Robert
• Walter Harald
• Mader Sebastian

Classifications

• B42D25/351

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

• B42D2035/36

  Operations & Transport · mapped topic

• B42D25/328 Primary

  Diffraction gratings; Holograms · CPC title

• B42D25/29 Primary

  Securities; Bank notes · CPC title

• B42D25/00

  Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof (printing processes to produce identification or security features B41M3/14) · CPC title