Optically variable security element
View Patent ↗An optically variable security element is provided for protecting objects of value. The reflective area region includes two independent relief structures, which are arranged at different levels in the z-direction and form a lower-level relief structure and a higher-level relief structure. The higher-level relief structure is supplied with a first reflection-enhancing coating following the relief profile, and the lower-level relief structure is supplied with a second reflection-enhancing coating following the relief profile. The first reflection-enhancing coating is formed in the visible spectral range with a reflection and transmission in the visible spectral range, so that the higher-level relief structure shows a first optically variable effect in a first color, and the lower-level relief structure shows a second optically variable effect through the first reflection-enhancing coating, wherein the second optically variable effect shows itself in a second, different color.
1. An optically variable security element for protecting objects of value, the area extension of which defines a z-axis perpendicular thereto, with a reflective area region that shows at least two optically variable effects which can be recognized from different viewing directions, and which appear with different colors, wherein
the reflective area region includes two independent relief structures comprising micromirror arrangements with directionally reflective micromirrors, which are arranged at different height levels in the z-direction and form a lower-level and a higher-level relief structure,
the higher-level relief structure is supplied with a first reflection-enhancing coating following the relief profile, and the lower-level relief structure is supplied with a second reflection-enhancing coating following the relief profile;
the two relief structures overlap in a feature region, and
the first reflection-enhancing coating is formed in the visible spectral range with a wavelength-dependent reflection and transmission in the visible spectral range, so that
the higher-level relief structure provides a first optically variable effect visible for a viewer in a first color and in a first viewing angle range, and
the lower-level relief structure provides a second optically variable effect through the first reflection-enhancing coating, wherein the second optically variable effect is visible for the viewer in a second, different color and in a second viewing angle range different from the first viewing angle range,
wherein the first reflection-enhancing layer is present in the feature region in a non-gridded manner.
2. The security element according to claim 1 , wherein the first reflection-enhancing coating has a wavelength-dependent reflection and a wavelength-dependent transmission in the visible spectral range, so that due to the reflection color effect of the first reflection-enhancing coating, the higher-level relief structure shows the first optically variable effect in the first color, and due to the transmission color effect of the first reflection-enhancing coating, the lower-level relief structure shows the second optically variable effect in the second color.
3. The security element according to claim 1 , wherein the two independent relief structures are formed differently.
4. The security element according to claim 1 , wherein the first reflection-enhancing coating has a transmission of at least 35% at least in a sub-range of the visible spectral range.
5. The security element according to claim 1 , wherein the first reflection-enhancing coating has a reflection of at least 30%, at least in a sub-range of the visible spectral range.
6. The security element according to claim 1 , wherein the first reflection-enhancing coating includes one or several highly refractive layers, highly refractive dielectric layers, which have a refractive index of at least 1.7, at least in a sub-range of the visible spectrum.
7. The security element according to claim 1 , wherein the second reflection-enhancing coating has a reflectance of at least 50%, at least in a sub-range of the visible spectrum, that the second reflection-enhancing coating is formed to be opaque with an optical density of more than 1.0.
8. The security element according to claim 1 , wherein the security element at least in a sub-region directs light of a first wavelength range of the visible spectrum with a reflectance R1 into a first viewing angle range and directs light of a second wavelength range of the visible spectrum with a reflectance R2 into a second viewing angle range, wherein there holds R1+R2>1.
9. The security element according to claim 1 , wherein the first and/or second reflection-enhancing layer is present in the feature region in a non-gridded manner, over the entire area.
10. The security element according to claim 1 , wherein one or several light-transmissive ink layers are provided between the first and the second relief structure in order to influence the color impression of the optically variable effect of the second relief structure.
11. The security element according to claim 1 , wherein one or several light-transmissive ink layers are provided above the first reflection-enhancing layer in order to influence the color impression of the optically variable effects of the first and the second relief structure.
12. The security element according to claim 1 , wherein
the transmission color effect of the first reflection-enhancing coating determines the second color; or
the transmission color effect of the first reflection-enhancing coating determines the second color together with a reflection color effect of the second reflection-enhancing coating and/or with at least one of the light-transmissive ink layers; or
a reflection color effect of the second reflection-enhancing coating and/or the color effect of at least one of the light-transmissive ink layers determines the second color.
13. The security element according to claim 1 , wherein in a certain region the first relief structure reflects incident parallel light into a first angle range and the second relief structure reflects the incident parallel light into a second angle range,
wherein the first angle range and the second angle range do not overlap.
14. The security element according to claim 1 , wherein a formation of the higher-level relief structure and/or a formation of the lower-level relief structure, varies in location-dependent manner in order to produce a predetermined motif in each case, a motif with a three-dimensional effect or a kinetic motif.
15. A data carrier with an optically variable security element according to claim 1 .
16. A method for manufacturing an optically variable security element with a reflective area region that shows at least two optically variable effects which can be recognized from different viewing directions, and which appear with different colors, according to claim 1 , in which
a carrier is made available, the area extension of which defines a plane and a z-axis perpendicular thereto,
the carrier is supplied with a reflective area region which includes two independent relief structures which are arranged at different height levels in the z-direction and form a lower-level and a higher-level relief structure,
the higher-level relief structure is supplied with a first reflection-enhancing coating following the relief profile, and the lower-level relief structure is supplied with a second reflection-enhancing coating following the relief profile,
the two relief structures are formed to overlap in a feature region,
the first reflection-enhancing coating in the feature region is formed with a wavelength-dependent reflection and transmission in the visible spectral range, so that
the higher-level relief structure due to the reflection color effect of the first reflection-enhancing coating, shows a first optically variable effect in a first color, and
the lower-level relief structure shows a second optically variable effect through the first reflection-enhancing coating, which, due to the transmission color effect of the first reflection-enhancing coating, shows itself in a second, different color.