Security element having a color filter, document of value having such a security element and production method for such a security element

A security element for security papers, comprising:

• a carrier having an upper side, said upper side being height-modulated with trenches periodically disposed in a first direction, each of the trenches having a trench depth (t);
• a multilayer structure acting as a color filter, said multilayer structure being formed on the height-modulated upper side and being height-modulated;
• said multilayer structure comprising a first layer, a second layer of dielectric material formed thereon, and a third layer formed on the second layer;
• the trench depth (t) being greater than a thickness of the third layer;
• the first and third layers each being formed of metallic material or semimetallic material:
• wherein at least one or more of (a), (b), (c), (d), and (e) below are satisfied:
• (a) a subwavelength grating period of the height-modulated multilayer structure is configured to cause a color change in the multilayer structure by the subwavelength grating period being laterally-varied from a first lateral position to a second lateral position within the multilayer structure of the security element;
• (b) a grating profile of the height modulations of the of the height-modulated multilayer structure is laterally varied from a first lateral position to a second lateral position within the multilayer structure of the security element;
• (c) metallic nanoparticles are incorporated in the second layer, and a distribution of the nanoparticles is laterally varied from a first lateral position to a second lateral position within the multilayer structure of the security element causing the color filter effect of the multilayer structure to vary laterally;
• (d) a modulation depth of the height-modulated multilayer structure is laterally varied from a first lateral position to a second lateral position within the multilayer structure of the security element;
• or
• (e) a layer thickness of the second layer is laterally varied from a first lateral position to a second lateral position within the multilayer structure of the security element,
• wherein the multilayer structure has a fourth and a fifth layer;
• the fourth layer being formed on the third layer and comprising a dielectric material;
• and
• the fifth layer being formed on the fourth layer, the fifth layer being formed of a dielectric material having a refractive index higher than that of the second layer and the forth layer, a metallic material, or a semimetallic material.

A security element for security papers, comprising:

• a carrier having an upper side, said upper side being height-modulated with trenches periodically disposed in a first direction, each of the trenches having a trench depth (t);
• a multilayer structure acting as a color filter, said multilayer structure being formed on the height-modulated upper side and being height-modulated;
• said multilayer structure comprising a first layer, a second layer of dielectric material formed thereon, and a third layer formed on the second layer;
• the trench depth (t) being greater than a thickness of the third layer;
• the first and third layers each being formed of metallic material or semimetallic material:
• wherein at least one or more of (a), (b), (c), (d), and (e) below are satisfied:
• (a) a subwavelength grating period of the height-modulated multilayer structure is configured to cause a color change in the multilayer structure by the subwavelength grating period being laterally-varied from a first lateral position to a second lateral position within the multilayer structure of the security element;
• (b) a grating profile of the height modulations of the of the height-modulated multilayer structure is laterally varied from a first lateral position to a second lateral position within the multilayer structure of the security element;
• (c) metallic nanoparticles are incorporated in the second layer, and a distribution of the nanoparticles is laterally varied from a first lateral position to a second lateral position within the multilayer structure of the security element causing the color filter effect of the multilayer structure to vary laterally;
• (d) a modulation depth of the height-modulated multilayer structure is laterally varied from a first lateral position to a second lateral position within the multilayer structure of the security element;
• or
• (e) a layer thickness of the second layer is laterally varied from a first lateral position to a second lateral position within the multilayer structure of the security element,
• wherein the trench depth (t) is greater than a sum of a thickness of the third layer, a thickness of the second layer, and a thickness of the first layer.