EP4210962A1 - Élément de sécurité optiquement variable - Google Patents

Élément de sécurité optiquement variable

Info

Publication number
EP4210962A1
EP4210962A1 EP21752496.6A EP21752496A EP4210962A1 EP 4210962 A1 EP4210962 A1 EP 4210962A1 EP 21752496 A EP21752496 A EP 21752496A EP 4210962 A1 EP4210962 A1 EP 4210962A1
Authority
EP
European Patent Office
Prior art keywords
reflection
security element
lying
relief structure
coating
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP21752496.6A
Other languages
German (de)
English (en)
Other versions
EP4210962B1 (fr
Inventor
Kai Herrmann SCHERER
Maik Rudolf Johann Scherer
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Giesecke and Devrient Currency Technology GmbH
Original Assignee
Giesecke and Devrient Currency Technology GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Giesecke and Devrient Currency Technology GmbH filed Critical Giesecke and Devrient Currency Technology GmbH
Publication of EP4210962A1 publication Critical patent/EP4210962A1/fr
Application granted granted Critical
Publication of EP4210962B1 publication Critical patent/EP4210962B1/fr
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B42—BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
    • B42D—BOOKS; BOOK COVERS; LOOSE LEAVES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITY FEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOT OTHERWISE PROVIDED FOR; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDED FOR; MOVABLE-STRIP WRITING OR READING APPARATUS
    • B42D25/00—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
    • B42D25/30—Identification or security features, e.g. for preventing forgery
    • B42D25/324—Reliefs
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B42—BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
    • B42D—BOOKS; BOOK COVERS; LOOSE LEAVES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITY FEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOT OTHERWISE PROVIDED FOR; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDED FOR; MOVABLE-STRIP WRITING OR READING APPARATUS
    • B42D25/00—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
    • B42D25/30—Identification or security features, e.g. for preventing forgery
    • B42D25/328—Diffraction gratings; Holograms
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B42—BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
    • B42D—BOOKS; BOOK COVERS; LOOSE LEAVES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITY FEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOT OTHERWISE PROVIDED FOR; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDED FOR; MOVABLE-STRIP WRITING OR READING APPARATUS
    • B42D25/00—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
    • B42D25/30—Identification or security features, e.g. for preventing forgery
    • B42D25/351—Translucent or partly translucent parts, e.g. windows
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B42—BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
    • B42D—BOOKS; BOOK COVERS; LOOSE LEAVES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITY FEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOT OTHERWISE PROVIDED FOR; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDED FOR; MOVABLE-STRIP WRITING OR READING APPARATUS
    • B42D25/00—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
    • B42D25/30—Identification or security features, e.g. for preventing forgery
    • B42D25/36—Identification or security features, e.g. for preventing forgery comprising special materials
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B42—BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
    • B42D—BOOKS; BOOK COVERS; LOOSE LEAVES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITY FEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOT OTHERWISE PROVIDED FOR; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDED FOR; MOVABLE-STRIP WRITING OR READING APPARATUS
    • B42D25/00—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
    • B42D25/30—Identification or security features, e.g. for preventing forgery
    • B42D25/36—Identification or security features, e.g. for preventing forgery comprising special materials
    • B42D25/373—Metallic materials

Definitions

  • the invention relates to an optically variable security element for protecting objects of value, with a reflective surface area that exhibits at least two optically variable effects recognizable from different viewing directions.
  • the invention also relates to a method for producing such a security element and to a data carrier equipped with such a security element.
  • Data carriers such as valuables or ID documents, but also other valuables, such as branded items, are often provided with security elements for protection, which allow the authenticity of the data carriers to be checked and which at the same time serve as protection against unauthorized reproduction.
  • the security elements can be designed, for example, in the form of a security thread embedded in a bank note, a cover film for a bank note with a hole, an applied security strip, a self-supporting transfer element or also in the form of a feature area printed directly on a document of value.
  • Security elements with a viewing angle-dependent or three-dimensional appearance play a special role in securing authenticity, as these cannot be reproduced even with the most modern copiers.
  • the security elements are equipped with optically variable elements that give the viewer a different image impression from different viewing angles and, for example, depending on the viewing angle, show a different color or brightness impression, a different perspective view and/or a different graphic motif.
  • the prior art describes, for example, movement effects, pump effects, depth effects or flip effects as optically variable effects, which are realized with the aid of holograms, microlenses or micromirrors.
  • the publication DE 102018005447 A1 proposed optically variable security elements which have two relief structures which are arranged at different height levels and are each provided with a color coating.
  • the color coating of the higher-lying relief structure is structured as a grid, so that the color coating of the lower-lying relief structure appears in the spaces between the grids when the security element is viewed.
  • This design enables a transition-free change from a first to a second appearance when the security element is tilted.
  • the realization of the necessary fine screening of the color coating is technologically very demanding.
  • the invention is based on the object of proposing a generic optically variable security element that is easy to produce, has an attractive visual appearance and can be used in a variety of ways to authenticate data carriers.
  • the invention contains an optically variable security element with a multicolored reflective surface area, which can be used in particular to protect valuables.
  • the reflective surface area shows at least two optically variable effects that are recognizable from different viewing directions and appear with different first and second colors, and when viewed through it shows an appearance in a third, different color.
  • the third color is different from both the first and the second color.
  • color includes not only chromatic colors, but also achromatic colors, ie in particular white, black, gray, and essentially silvery metallic colors, such as the color of a reflective aluminum or silver layer.
  • the reflective surface area contains two independent relief structures, which are arranged at different height levels in the z-direction and form a lower-lying and a higher-lying relief structure.
  • the two relief structures overlap in a feature area, with partial overlapping or complete overlapping, ie formation in congruent surface areas, being possible.
  • the higher-lying relief structure is provided with a first reflection-increasing coating following the course of the relief, which has wavelength-dependent reflection and transmission in the visible spectral range and thereby at least one reflection band and at least one transmission band.
  • the lower-lying relief structure is provided with a second reflection-increasing coating following the course of the relief, which has a wavelength-dependent reflection and transmission in the visible spectral range and also at least one reflection band and at least one
  • the higher-lying relief structure and the lower-lying relief structure are matched to one another in that a reflection band of the second reflection-enhancing coating lies at least partially in a transmission band of the first reflection-enhancing coating, and in that at least one transmission band of the two reflection-enhancing coatings overlaps.
  • the higher-lying relief structure shows a first optically variable effect in the first color and the lower-lying relief structure shows a second optically variable effect in the second, different color through the first reflection-enhancing coating.
  • an appearance in the third color which differs from the first and second color, can be seen through the higher-lying and the lower-lying relief structure.
  • the first and/or second reflection-increasing coating has a transmission of at least 35%, preferably at least 50%, particularly preferably at least 65%, in its transmission bands of the visible spectral range.
  • the first and/or second reflection-increasing coating has a reflection in its reflection bands of the visible spectral range. xion of at least 20%, preferably at least 30%, more preferably at least 40%.
  • the first reflection-increasing coating preferably contains one or more high-index layers, preferably dielectric high-index layers, which have a refractive index of at least 1.7, preferably at least 2.0 and particularly preferably at least 2.2, at least in a portion of the visible spectrum .
  • the first reflection-increasing coating can be formed by a ZnS layer with a thickness between 50 nm and 400 nm.
  • the second reflection-increasing coating advantageously contains one or more high-index layers, preferably dielectric high-index layers, which have a refractive index of at least 1.7, preferably at least 2.0 and particularly preferably at least in a portion of the visible spectrum 2.2.
  • the second reflection-increasing coating can be formed by a ZnS layer with a thickness of between 50 nm and 400 nm.
  • the first and second reflection-increasing coatings are each formed by a ZnS layer, with the layer thicknesses of the two coatings differing by 35 nm or more.
  • a reflection band of the second reflection-increasing coating lies at least partially in a transmission band of the first reflection-increasing coating, as desired.
  • the second reflection-increasing coating represents a multi-layer system with a layer consists of metal/dielectric/metal, in particular aluminum/SiCh/aluminum, the metal layers of the multilayer system, in particular the aluminum layers, having a layer thickness of 5 nm or less, preferably 4 nm or less.
  • the multilayer system is advantageously designed in such a way that its reflection and transmission are between 30% and 70%.
  • the first reflection-increasing coating can also be formed by a multi-layer system of the type mentioned, even if high-index individual layers, for example a ZnS layer, are currently particularly preferred for the first reflection-increasing coating.
  • the higher-lying relief structure and/or the lower-lying relief structure are formed by micromirror arrangements with specularly reflecting micromirrors, in particular with non-diffractive mirrors, and preferably with flat mirrors, concave mirrors and/or Fresnel-like mirrors.
  • the lateral dimensions of the micromirrors are expediently below 50 ⁇ m, advantageously below 20 ⁇ m, preferably around 10 ⁇ m, ie between 7 ⁇ m and 13 ⁇ m.
  • the lateral dimensions of the micromirrors are also above 2 ⁇ m, in particular above 3 ⁇ m or even above 5 ⁇ m.
  • the pitch of the micromirrors is preferably less than 10 ⁇ m, preferably less than 5 ⁇ m.
  • the relief structures can also include other embossed relief structures, in particular Fresnel lenses, concave mirrors, hologram structures, nanostructures or diffractive blazed gratings.
  • embossed relief structures in particular Fresnel lenses, concave mirrors, hologram structures, nanostructures or diffractive blazed gratings.
  • achromatic diffraction gratings so-called matte structures, which essentially reflect white light, can also be used.
  • the relief structures can at least the second relief structure also have sub-wave structures, in particular sub-wavelength gratings, which, in combination with the respective reflection-increasing layer, determine or at least co-determine the color thereof.
  • one or both relief structures can also be formed by a layer with a multiplicity of three-dimensionally aligned platelet-shaped pigments.
  • the flake-form pigments are particularly advantageously flake-form magnetic pigments that can be aligned by a magnetic field, but they can also be flake-form effect pigments that can be aligned by other fields, for example electric fields.
  • the aligned pigments not only lie flat in the plane of the surface area, but are at least partially tilted with respect to this plane. Due to its three-dimensional alignment with a tilting component against the plane, the surface formed by the pigments also represents a relief structure, similar to the embossed structures described above.
  • a first of the three colors mentioned is red or reddish, a second is green or greenish and a third is blue or bluish.
  • the color that is visible when viewed through is also advantageously an achromatic color, in particular with a gray or metallic appearance.
  • both reflection-increasing layers are not screened and in particular are even applied to the surface pattern over the entire surface.
  • a particular advantage of the design according to the invention consists precisely in the fact that the optically variable effect of the underlying relief structure is visible despite a first reflection-increasing coating that is present without a grid or over the entire surface.
  • the second reflection-increasing layer can also be provided only in certain areas and thereby form negative identifiers, in particular in the form of numbers, symbols and the like, in the security element. Additionally or alternatively, the first reflection-increasing coating can only be present in certain areas.
  • the areas in which the two different reflection-increasing coatings are provided must overlap at least in areas in the feature area.
  • the two reflection-increasing coatings are not provided over the entire area, but in partial areas that are completely or almost congruent.
  • a negative identifier can be designed in such a way that both reflection-increasing coatings are left out congruently in the form of text, symbols, numbers and the like.
  • the first reflection-increasing layer is therefore advantageously unrastered in the feature area, that is to say without a raster, but possibly with individual negative features.
  • the first reflection-increasing layer is even present over the entire area in the feature region, ie without grids and cutouts.
  • one or more translucent color layers can be provided between the first and second relief structure and/or above the first reflection-enhancing coating and/or below the second reflection-enhancing coating in order to enhance the color impression of the security element influence.
  • Each of these color layers can be present over the entire surface or only in certain areas, in particular in the form of patterns, characters or a code.
  • a color layer can be provided below the second reflection-increasing coating, which absorbs more strongly in some areas and less in some areas in the overlapping transmission area of the two reflection-increasing coatings, resulting in a structured appearance when viewed through.
  • the optically variable effects of the two relief structures are not congruent; rather, they are at least partially recognizable from different viewing directions.
  • the first and second relief structure at least partially reflect incident parallel light in different angular ranges, the two different angular ranges preferably not overlapping and preferably being separated from one another by more than 3°, particularly preferably more than 10°.
  • the two relief structures are independent relief structures. They can therefore be chosen freely, since they do not depend on one another (in terms of their relief pattern).
  • a relief structure that results solely by coating another relief structure is not an independent relief structure in the present sense.
  • the relief structures of the surface area do not have the same relief pattern, nor the same relief pattern scaled only in height, but rather the two relief structures are designed differently and with different relief patterns.
  • the two independent relief structures are particularly different.
  • the two relief structures can therefore produce optically variable effects of the same type, for example opposing movement effects or spatial representations visible from different viewing directions, but they will not always produce the same optically variable effect at the same location due to the different relief patterns .
  • the formation of the higher-lying relief structure in particular the alignment of the micromirrors of the higher-lying micromirror arrangement and/or the formation of the lower-lying relief structure, in particular the alignment of the micromirrors of the lower-lying micromirror arrangement, can advantageously vary depending on the location. in order to generate a given motif, in particular a motif that appears three-dimensional or a motif in motion.
  • the relief pattern in particular the alignment of the micromirrors, can be freely selected and essentially only determined by the specified motifs, but not by the alignment of laterally or vertically adjacent micromirrors.
  • the invention further includes a data carrier with a security element of the type described A certificate, a voucher, a cheque, a high-value admission ticket, but also an identity card, such as a credit card, a bank card, a cash payment card, an authorization card, an identity card or a passport personalization page.
  • the lower-lying relief structure is generally closer to a surface of the data carrier than the higher-lying relief structure, which is closer to the viewer's eye.
  • the security element is arranged in a particularly expedient variant in a window area, ie in a transparent or perforated area of the data carrier.
  • the security element can also be arranged over an opaque area of the data carrier and, for example, enable information stored on the data carrier to be viewed.
  • the invention also includes a method for producing an optically variable security element with a reflective surface area that shows at least two optically variable effects that can be seen from different viewing directions and appear with different colors, and in particular provides a method for producing a security element - ments of the type described above, in which - a carrier is provided, the surface extent of which defines a plane and a z-axis perpendicular thereto, - the carrier is provided with a reflective surface area which contains two independent relief structures which in z- Direction are arranged at different height levels, and form a lower and a higher relief structure, and which are designed to overlap in a feature area, the higher relief structure with a first reflection-increasing coating following the relief course with a wave nlength-dependent reflection and transmission in the visible spectral range is provided, which has at least one reflection band and at least one transmission band, the deeper-lying relief structure with a second reflection-increasing coating following the relief course with a wavelength-dependent reflection and transmission in the visible spectral range is provided
  • FIG. 1 shows a schematic representation of a bank note with an optically variable security element according to the invention
  • FIG. 1 shows a schematic representation of a banknote 10 with an optically variable security element 12 according to the invention in the form of a transfer element glued on.
  • the invention is not limited to transfer elements and banknotes, but can be used with all types of security elements, for example labels on goods and packaging or to protect documents, ID cards, passports, credit cards, health cards and the like.
  • transfer elements such as patches or strips, each with or without their own backing layer
  • security threads or security strips for example, can also be considered.
  • the security element 12 shown in FIG. 1 is arranged in a window area 15 of the bank note 10 and covers there, for example, a continuous opening of the bank note.
  • a first motif 14-A apparently arching out of the plane of the bank note 10, specifically, for example, a curved representation of the denomination “10” that appears with a first color, for example a green color impression.
  • the Si Security element 12 has a second motif 14-B that appears to bulge out of the plane of banknote 10, for example a curved depiction of a coat of arms that appears in a second color, for example a reddish color impression.
  • the security element 12 also allows a view through the security element and the window area 15 of the banknote, the security element appearing in a third color different from the two supervisory colors, for example with a blue color impression.
  • FIG. 2 shows a section of the security element 12 schematically in cross section.
  • the security element 12 contains a flat, transparent carrier film 18, the surface extent of which defines an xy plane and a z-axis perpendicular thereto.
  • the carrier film 18 carries a multicolored reflective surface area 20, which contains two relief structure areas 24, 34, which are arranged in the z-direction at two specific, different height levels.
  • the relief structure 34 that is closer to the viewer 40-A, 40-B when viewed from above is referred to as the higher relief structure, and the relief structure 24 that is further away from the viewer is referred to as the lower relief structure.
  • the two relief structure areas each represent micromirror embossings or micromirror arrangements 24, 34, which are each formed from a multiplicity of micromirrors inclined with respect to the x-y plane and having lateral dimensions of approximately 10 ⁇ m.
  • the local angles of inclination of the micromirrors are selected in such a way that the relief structures of the micromirror arrangements 24, 34 produce a desired optical appearance after the reflection-increasing coating.
  • angles of inclination of the micromirrors in the exemplary embodiment are selected such that the micromirror arrangement 34 generates the curved representation of the value number “10” in a viewing angle range of +5° to +20° (viewing position 40-A) related to the surface normal the micromirror arrangement 24 produces the curved representation of the coat of arms in a viewing angle range of -5° to -20° (viewing position 40-B).
  • the higher-lying micromirror arrangement 34 is provided over its entire surface with a first reflection-increasing coating 36 in the form of a semi-transparent, high-index ZnS layer that follows the relief pattern Has reflection and transmission.
  • the lower-lying micromirror arrangement 24 is provided over the entire surface with a second reflection-increasing coating 26 following the relief pattern, which is formed by a semitransparent three-layer system made of 3 nm Al/200 nm SiO 2 /3 nm Al and has wavelength-dependent reflection and transmission.
  • the micromirror arrangements 24, 34 are each embossed into a transparent embossing lacquer layer 22, 32 applied to opposite sides of the carrier film 18 and, after the application of the respective reflection-increasing coating 26, 36, is leveled with a transparent top lacquer layer 28 or 38, respectively.
  • the cover lacquer layers preferably have essentially the same refractive index as the embossing lacquer layers 22 , 32 .
  • the micromirrors of the higher-lying micromirror arrangement 34 are in the specular angle for the observer from the viewing direction 40-A in plan view. kel, which produce the arched representation of the value number "10". Because of its reflection band in the green spectral range, the first reflection-increasing coating 36 produces an image impression with a green reflection color 52. Because of the semi-transparency of the reflection-increasing coating 36, the micromirrors of the micromirror arrangement 24 are basically also perceptible, but their orientation is wide away from the glancing angle and they therefore appear inconspicuous from the viewing direction 40-A and practically do not contribute to the image impression. Overall, the green appearance 14-A of the curved denomination “10” produced by the micromirror arrangement 34 is seen by the observer from the viewing direction 40-A in a top view.
  • the micromirrors of the lower-lying micromirror arrangement 24 are at the glancing angle for the viewer, which generate the curved representation of the coat of arms. Due to its transmission bands in the red and blue spectral range, the first reflection-enhancing coating 36 of the higher-lying micromirror arrangement 34 transmits the red portion 54 and the blue portion 56 of the incident white light 50 to the second reflection-enhancing coating 26 of the deeper micromirror array 24.
  • the second reflection-enhancing coating 26 reflects the red spectral component 54 in the viewing direction 40-B, which is also transmitted by the first reflection-enhancing coating 36 due to its transmission band in the red spectral range.
  • the micromirrors of the higher-lying micromirror arrangement 34 can basically also be seen from the viewing direction 40-B, their orientation is far removed from the specular angle and they therefore appear inconspicuous and contribute to the image practically does not print. Overall, the observer from the viewing direction 40-B thus sees the reddish appearance 14-B of the curved coat of arms generated by the micromirror arrangement 24.
  • the glancing angle of the micromirrors 24, 34 for reflection plays no role; the appearance is rather determined by the transmitted radiation components of the two reflection-increasing coatings 26, 36, since the first reflection-increasing coating 36 is the red one Portion 54 and the blue portion 56 of the incident white light 50 are transmitted and the second reflection-increasing coating 26 still transmits the blue spectral portion 56 due to its transmission band in the blue spectral range, the viewer from the viewing direction 40-C sees through the surface area 20 with a blue color impression.
  • FIG. 3 shows, in a highly schematic manner, the different wavelength-dependent reflection and transmission of the two reflection-increasing coatings 36, 26 and the resulting transmission and reflection spectra of the entire surface area 20.
  • the diagram 60 of FIG. 3(a) for the first reflection-enhancing coating 36 shows the wavelength-dependent reflection as a solid curve R 1 ( ⁇ ) and the wavelength-dependent transmission as a dashed curve T 1 ( ⁇ ).
  • the coating 36 shown has a reflection band in the green spectral range (G) and transmission bands in the red spectral range (R) and blue spectral range (B).
  • the diagram 62 of FIG. 3(b) correspondingly shows the wavelength-dependent reflection for the second reflection-increasing coating 26 as a solid curve R2 ( ⁇ ) and the wavelength-dependent transmission as a dashed curve T2 ( ⁇ ).
  • the coating 26 shown has a reflection band in the red spectral range (R) and a transmission band in the green spectral range (G) and blue spectral range (B).
  • Diagram 64 of FIG. 3(c) summarizes the resulting transmission and reflection spectra of the entire surface area 20. From the viewing direction 40-A, the appearance of the surface area 20 is determined by the reflectivity of the first reflection-increasing coating 36. so
  • the appearance of the surface area 20 results from the light transmitted by the first reflection-enhancing coating 36 and the light reflected by the second reflection-enhancing coating 26.
  • the incident light after being reflected at the second reflection-enhancing coating 26, passes through the first reflection-enhancing coating 36 once more (see, for example, FIG. 2), so its transmission is twice must be taken into account.
  • the result for the reflectivity viewing direction 40-B is:
  • R B ( ⁇ ) T 1 ( ⁇ ) * R 2 ( ⁇ ) * T 1 ( ⁇ ), so that from this viewing direction through the transmission bands of the first anti-reflective coating in the red and blue spectrum ral range and the reflection band of the first reflection-increasing coating results in a reddish overall appearance in the red spectral range
  • T C ( ⁇ ) T 1 ( ⁇ ) * T 2 ( ⁇ ), so that through the transmission bands of the first reflection-enhancing coating 36 in the red and blue spectral range and the transmission onsband of the second reflection-enhancing coating 26 in the blue spectral range overall a blue gives a color impression.
  • FIG. 4 shows a security element 70 in which the layers already described in connection with FIG. 2 have been applied to the same side of a carrier film 18 .
  • the security element 70 contains a first transparent embossed lacquer layer 32 with an embossed, higher-lying micromirror structure 34, a first reflection-increasing coating 36, a second transparent embossed lacquer layer 22 applied to the coating 36 with an embossed, lower-lying micromirror structure 24, a second reflection-enhancing coating 26, a topcoat layer 28 and finally an adhesive layer 44 for transferring the security element 70 to a target substrate.
  • the carrier film 18 is preferably designed to be releasable and is pulled off after the security element 70 has been transferred. Alternatively, the carrier film 18 can also remain in the transferred layer composite if it is transparent.
  • the first reflection-increasing coating 36 is formed by a semitransparent, high-index ZnS layer with wavelength-dependent reflection and transmission.
  • the ZnS layer 36 primarily reflects the incident red and blue light, a small proportion of red and blue light is also transmitted.
  • the second reflection-increasing coating 26 is also formed by a semitransparent, high-index ZnS layer with wavelength-dependent reflection and transmission.
  • the first reflection-increasing coating 36 produces an image impression with a violet reflection color because of its reflection bands in the red and blue spectral range.
  • the color impression results, as described above, from an interaction of the spectral component transmitted by the first reflection-increasing coating 36 and the spectral component reflected therefrom at the second reflection-increasing coating 26 .
  • the first reflection-enhancing coating 36 has a transmission band in the green spectral range, with a small portion of blue light also being transmitted. Because of the pronounced reflection bands of the second reflection-increasing coating 26 in the blue and green spectral range, the micromirrors of the lower-lying micromirror arrangement 24 therefore appear to the viewer with a blue/green/turquoise color.
  • the micromirrors of the micromirror arrangement 34 which are not in the specular angle, appear inconspicuous from this viewing direction and practically do not contribute to the image impression.
  • the appearance is determined by the respective transmitted radiation components, with the first reflection-increasing coating 36 transmitting green light to a large extent and red and blue light to a small extent.
  • the second reflection-enhancing coating 26 transmits red light strongly, but also transmits blue and green light to a small extent.
  • the total transmission of the two reflection-increasing coatings is an almost balanced spectrum with a slight emphasis on the transmission in the red, so that the observer sees an essentially achromatic color, namely an aluminum-colored transparent color with a reddish hue.

Landscapes

  • Credit Cards Or The Like (AREA)
  • Diffracting Gratings Or Hologram Optical Elements (AREA)
  • Optical Filters (AREA)

Abstract

L'invention concerne un élément de sécurité optiquement variable (12) ayant une région plate réfléchissante (20), qui, dans l'éclairage avant, présente au moins deux effets optiquement variables qui peuvent être détectés à partir de différentes directions de visualisation et qui apparaissent avec des première et seconde couleurs différentes, et qui, dans l'éclairage arrière, présente une image dans une troisième couleur différente. Selon l'invention, la région plate réfléchissante (20) contient deux structures en relief séparées (24, 34) qui forment une structure en relief inférieure et une structure en relief supérieure et qui se chevauchent dans une région caractéristique. Les structures en relief supérieure et inférieure (24, 34) sont chacune pourvues d'un revêtement augmentant la réflexion (26, 36) qui suit le tracé du relief et qui a une réflexion et une transmission dépendant de la longueur d'onde dans la plage spectrale visible et a au moins une bande de réflexion et au moins une bande de transmission. Une bande de réflexion du second revêtement augmentant la réflexion (26) est au moins partiellement dans une bande de transmission du premier revêtement augmentant la réflexion (36) et chevauche au moins une bande de transmission des deux revêtements augmentant la réflexion (26, 36).
EP21752496.6A 2020-09-14 2021-08-03 Élément de sécurité optiquement variable Active EP4210962B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102020005607.5A DE102020005607A1 (de) 2020-09-14 2020-09-14 Optisch variables Sicherheitselement
PCT/EP2021/025292 WO2022053174A1 (fr) 2020-09-14 2021-08-03 Élément de sécurité optiquement variable

Publications (2)

Publication Number Publication Date
EP4210962A1 true EP4210962A1 (fr) 2023-07-19
EP4210962B1 EP4210962B1 (fr) 2024-10-09

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP21752496.6A Active EP4210962B1 (fr) 2020-09-14 2021-08-03 Élément de sécurité optiquement variable

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CN (1) CN116075435A (fr)
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DE102005017169B4 (de) 2005-04-13 2023-06-22 Ovd Kinegram Ag Transferfolie
DE102007019522A1 (de) 2007-04-25 2008-10-30 Giesecke & Devrient Gmbh Durchsichtssicherheitselement
DE102010022123C5 (de) 2010-05-20 2023-03-02 Leonhard Kurz Stiftung & Co. Kg Sicherheitselement
DE102011108242A1 (de) * 2011-07-21 2013-01-24 Giesecke & Devrient Gmbh Optisch variables Element, insbesondere Sicherheitselement
JP6379547B2 (ja) * 2013-06-17 2018-08-29 凸版印刷株式会社 画像表示体および情報媒体
US20170203601A1 (en) * 2014-05-26 2017-07-20 Toppan Printing Co., Ltd Counterfeit preventing structure and counterfeit preventing article
FR3021583B1 (fr) * 2014-05-30 2021-10-22 Hologram Ind Composant optique de securite personnalisable pour la fabrication d'un document de securite personnalise et fabrication d'un tel composant
JP2017161872A (ja) * 2016-03-11 2017-09-14 凸版印刷株式会社 表示体及び情報印刷物
DE102017009226A1 (de) * 2017-10-04 2019-04-04 Giesecke+Devrient Currency Technology Gmbh Optisch variables Durchsichtssicherheitselement und Datenträger
DE102018005447A1 (de) 2018-07-09 2020-01-09 Giesecke+Devrient Currency Technology Gmbh Optisch variables Sicherheitselement mit reflektivem Flächenbereich

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DE102020005607A1 (de) 2022-03-17
WO2022053174A1 (fr) 2022-03-17
EP4210962B1 (fr) 2024-10-09
CN116075435A (zh) 2023-05-05

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