Security Element Having Groove- or Rib-Shaped Structural Elements
View Patent ↗A security element for manufacturing value documents, such as banknotes, checks or the like, comprises a top on which a microrelief structure is developed that has at least two sub-regions that each comprise a plurality of groove- and/or rib-shaped structural elements that lie adjacent to one another and extend along a longitudinal direction, and are reflecting or backscattering. The longitudinal directions of the sub-regions are different, and the structural elements are each not resolvable with the naked eye with respect to the width transverse to the longitudinal direction, and fan out incident parallel light achromatically in a fan that lies transverse to the longitudinal direction and has an opening angle of at least 30°.
1. A security element for manufacturing value documents comprises:
a top on which is developed a microrelief structure that has at least two sub-regions that each comprise a plurality of groove- and/or rib-shaped structural elements that lie adjacent to one another and extend along a longitudinal direction, and are reflecting or backscattering, the longitudinal directions of the sub-regions being different,
wherein the structural elements are each not resolvable with the naked eye with respect to the width transverse to the longitudinal direction, the width transverse to the longitudinal direction being below 50 μm, and fan out incident parallel light achromatically in a fan that lies transverse to the longitudinal direction and has an opening angle of at least 30°,
wherein the structural elements have an inclination angle of at most 45° with respect to a plane defined by the top, and
wherein, within the opening angle of the fan, the fanning out of the incident parallel light results in a substantially uniform distribution of reflected or backscattered light.
2. The security element according to claim 1 , wherein the fan has an opening angle of at least 45°.
3. The security element according to claim 1 , wherein the structural elements reflect or backscatter the incident parallel light along the longitudinal direction in such a way that it is fanned out by no more than 10°.
4. The security element according to claim 1 , wherein the structural elements, seen in each case transverse to the longitudinal direction, have a profile that exhibits no discontinuity.
5. The security element according to claim 1 , wherein, seen from the top, the structural elements are convex.
6. The security element according to claim 1 , wherein the width of the structural elements is, in each case, between 3 μm and 50 μm.
7. The security element according to claim 1 , wherein the profile has a cross section that is an arc of a circle, of a parabola or of an ellipse.
8. The security element according to claim 7 , wherein the structural elements are formed by grooves or ribs whose area corresponds to a portion of a lateral surface of a circular cylinder.
9. The security element according to claim 1 , wherein the structural elements are provided, at least in some regions, with a reflective or reflection-increasing coating.
10. The security element according to claim 1 , wherein the at least two sub-regions either are nested within each other, such that different depictions result for a viewer from different viewing directions, or are spaced apart in such a way that they present a stereogram.
11. The security element according to claim 1 , wherein at least five sub-regions are present whose longitudinal directions are different, such that, when the security element is rotated about an axis that lies perpendicular to the surface, a cinematic effect is presented to a viewer.
12. The security element according to claim 1 , wherein a plurality of sub-regions is present whose longitudinal directions differ, the longitudinal directions following a height contour line of a bulged area to present a 3-D effect to a viewer.
13. The security element according to claim 1 , wherein it comprises a transparent substrate foil in which the microrelief structure is developed, the security element permitting, from both sides, perception of the effect produced by the security element.
14. The security element according to claim 1 , wherein the structural elements are developed such that perpendicularly incident light is fanned out symmetrically about a surface normal.
15. The security element according to claim 1 , wherein a depth of the structural elements is half of the width transverse to the longitudinal direction.
16. A value document having a security element according to claim 1 .
17. A method for manufacturing a security element for value documents, wherein a substrate is provided that comprises a top, and on the top, a microrelief structure being developed that has at least two sub-regions that each comprise a plurality of groove- and/or rib-shaped structural elements that lie adjacent to one another and extend along a longitudinal direction, and are reflecting or backscattering, the longitudinal directions of the sub-regions being different,
wherein the structural elements are each not resolvable with the naked eye with respect to the width transverse to the longitudinal direction, the width transverse to the longitudinal direction being below 50 μm, and are developed in such a way that they fan out incident parallel light achromatically in a fan that lies transverse to the longitudinal direction and has an opening angle of at least 30°, and
wherein, within the opening angle of the fan, the fanning out of the incident parallel light results in a substantially uniform distribution of reflected or backscattered light such that within the opening angle of the fan, the observed brightness of the reflected or backscattered light varies by no more than a factor of 3.