Security element for a security document and process for the production thereof

Abstract

The invention concerns a security element for a security document comprising a structure layer and diffractive first and second relief structures, wherein the relief structures viewed parallel to the plane of the structure layer are arranged in different planes of the security element, wherein the first relief structure adjoins a partial first reflection layer and the second relief structure adjoins a partial second reflection layer, and wherein—if the first reflection layer is towards a viewer—a second item of information generated by the second relief structure is at least partially concealed and—if the second reflection layer is towards the viewer—a first item of information generated by the first relief structure is at least partially concealed, and processes for the production of such security elements and security documents formed therewith.

1 . A security element having at least one structure layer which is at least region-wise transparent, a diffractive first relief structure which is arranged at least region-wise, and a diffractive second relief structure which is arranged at least region-wise, wherein the first and second relief structures differ at least region-wise and are arranged in different planes of the security element as viewed parallel to the plane of the structure layer, wherein the first relief structure adjoins a first reflection layer with a first contour and the second relief structure adjoins a second reflection layer with a second contour, wherein
 the first reflection layer and the second reflection layer are arranged region-wise as viewed perpendicularly to the plane of the structure layer and at least region-wise overlap, wherein at least sub-regions of the first and second contour extend in congruent relationship with each other as viewed perpendicularly to the plane of the structure layer and in adjoining relationship with at least one transparent region of the structure layer and, if the first reflection layer is towards a viewers, a second item of information generated by the second relief structure in the region of the overlap is at least partially concealed and, if the second reflection layer is towards the viewer, a first item of information generated by the first relief structure in the region of the overlap is at least partially concealed.   
     
     
         2 . A security element according to  claim 1 , wherein the first and second items of information differ at least region-wise from each other. 
     
     
         3 . A security element according to  claim 1 , wherein the first reflection layer is opaque and when facing towards the viewer at least region-wise conceals the second information and further items of information generated by the second relief structure or the first reflection layer is transparent and at least one first opaque auxiliary layer at least region-wise conceals the second information and also further items of information generated by the second relief structure. 
     
     
         4 . A security element according to  claim 1 , wherein the second reflection layer is opaque and when facing towards the viewer at least region-wise conceals the first information and further items of information generated by the first relief structure or the second reflection layer is transparent and at least one second opaque auxiliary layer at least region-wise conceals the first information and also further items of information generated by the first relief structure. 
     
     
         5 . A security element according to  claim 3 , wherein first/second information and further generated items of information are each completely concealed. 
     
     
         6 . A security element according to  claim 1 , wherein the structure layer has the diffractive first relief structure on a first side and the diffractive second relief structure on a second side, wherein the first side adjoins the first reflection layer and the second side adjoins the second reflection layer. 
     
     
         7 . A security element according to  claim 1 , wherein the first and second reflection layers when viewed perpendicularly to the plane of the structure layer are predominantly or completely in mutually congruent relationship. 
     
     
         8 . A security element according to  claim 1 , wherein the first reflection layer, when facing towards the viewer, forms a front view of at least one graphic motif, wherein the front view shows the first information generated by the first relief structure, and the second reflection layer when facing towards the viewer forms a rear view of the at least one graphic motif, wherein the rear view shows the second information generated by the second relief structure. 
     
     
         9 . A security element according to  claim 8 , wherein at least one graphic motif is composed of image elements which are opaque when viewed at least in incident light and transparent image elements, wherein the image elements which are opaque at least in incident light of the front view are formed by the first reflection layer and the at least one first opaque auxiliary layer, wherein the image elements which are opaque at least in incident light of the rear view are formed by the second reflection layer and the at least one second opaque auxiliary layer, and wherein the transparent image elements are formed by transparent regions of the at least one structure layer, in combination with at least one further transparent layer. 
     
     
         10 . A security element according to  claim 8 , wherein the at least one graphic motif is a figurative representation, a portrait, an alphanumeric character, a text, a graphic pattern, a symbol or a logo. 
     
     
         11 . A security element according to  claim 3 , wherein the at least one first opaque auxiliary layer and/or the at least one second opaque auxiliary layer is/are formed by at least one metal layer and/or at least one printing ink layer and/or at least one opaquely coloured lacquer layer and/or opaque regions of the structure layer. 
     
     
         12 . A security element according to  claim 1 , wherein the first and/or second reflection layer is/are formed by at least one metal layer and/or at least one dielectric layer. 
     
     
         13 . A security element according to  claim 1 , wherein the first and second reflection layers differ in respect of material and/or colour. 
     
     
         14 . A security element according to  claim 1 , wherein the structure layer is of a layer thickness in the range of 0.3 to 3 μm. 
     
     
         15 . A security element according to  claim 1 , wherein the structure layer is overall transparent. 
     
     
         16 . A security element according to  claim 1 , wherein the security element when viewed in a transillumination situation has, in the region of at least one of the reflection layers, visibly differently transmissive regions which exhibit further information. 
     
     
         17 . A security document comprising at least one security element according to  claim 1 , wherein the at least one security element is arranged in at least one transparent region of the security document or in partially overlapping relationship therewith. 
     
     
         18 . A security document according to  claim 17 , wherein the security document has a translucent or opaque carrier substrate and there is a window opening in the carrier substrate in the at least one transparent region. 
     
     
         19 . A security document according to  claim 17 , wherein the security document has a transparent carrier substrate and the at least one security element is arranged on or embedded in the carrier substrate. 
     
     
         20 . A security document according to  claim 17 , wherein the security document has at least one transparent protection layer. 
     
     
         21 . A security document according to  claim 20 , wherein the security document has two transparent protection layers between which at least the carrier substrate and the at least one security element are enclosed. 
     
     
         22 . A security document according to  claim 17 , wherein the security document is an identity card, a passport, a certificate, a bank card, a credit card, a telephone card, a banknote, a driving licence or a visa. 
     
     
         23 . A process for the production of a security element according to  claim 1 , the process comprising the following steps:
 a) providing a transparent first replication layer;   b) forming a diffraction master relief structure on a first surface of the first replication layer;   c) forming the region-wise first reflection layer and at least one region-wise first opaque auxiliary layer, on the first surface;   d) forming the structure layer which is transparent in at least region-wise fashion by a second replication layer which is arranged on the first reflection layer and the at least one first opaque auxiliary layer and regions which are free therefrom of the first surface;   e) forming the diffractive second relief structure on a second side of the structure layer; and   f) forming the region-wise second reflection layer on the second side of the structure layer in a layer thickness, with which the second relief structure is shaped on the side, remote from the structure layer, of the second reflection layer.   
     
     
         24 . A process according to  claim 23 , wherein the first reflection layer and/or the second reflection layer is/are opaque. 
     
     
         25 . A process according to  claim 23 , wherein the first and/or the second reflection layer is transparent and viewed perpendicularly to the plane of the structure layer at least one opaque auxiliary layer is arranged in congruent relationship with the transparent reflection layer or layers. 
     
     
         26 . A process for the production of a security element according to  claim 1 , the process comprising the following steps:
 g) providing a transparent structure layer;   h) forming the diffractive first relief structure on a first side and the diffractive second relief structure on a second side of the structure layer;   i) forming the at least region-wise first reflection layer and at least one first opaque auxiliary layer on the first side of the structure layer; and   k) forming the at least region-wise second reflection layer and at least one second opaque auxiliary layer on the second side of the structure layer.   
     
     
         27 . A process according to  claim 23 , wherein the at least one opaque auxiliary layer is formed by the structure layer being exposed region-wise and by a transparent colouring agent contained in the structure layer being converted into an opaque coloured colouring agent in the exposed regions. 
     
     
         28 . A process according to the  claim 26 , wherein the first and second relief structures are formed simultaneously by stamping. 
     
     
         29 . A process according to  claim 23 , wherein the relief structures are formed by thermal replication or UV replication. 
     
     
         30 . A process according to  claim 23 , wherein, in step c) the first reflection layer is applied over the full surface area, a first photoresist layer is applied over the full surface area involved to the first reflection layer the first photoresist layer is partially exposed and removed, the first reflection layer is removed by etching in the regions in which the first photoresist layer was removed and the remaining regions of the first photoresist layer are removed or are used as a first opaque auxiliary layer. 
     
     
         31 . A process according to  claim 30 , wherein exposure of the first photoresist layer is effected through the first reflection layer, wherein partial exposure of the first photoresist layer is effected in dependence on the configuration and/or arrangement of the first relief structure. 
     
     
         32 . A process according to  claim 23 , wherein, in step f), the second reflection layer is applied over the full surface area involved, a second photoresist layer is applied over the full surface area to the second reflection layer, the second photoresist layer is partially exposed and removed, the second reflection layer is removed by etching in the regions in which the second photoresist layer was removed, and the remaining regions of the second photoresist layer are removed. 
     
     
         33 . A process according to  claim 32 , wherein exposure of the second photoresist layer is effected through the first and second reflection layers, wherein partial exposure of the second photoresist layer is effected in dependence on the configuration and/or arrangement of the first relief structure and/or the second relief structure.