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
  • B42D25/20—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof characterised by a particular use or purpose
  • B42D25/29—Securities; Bank notes
• • 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
  • B42D25/40—Manufacture
  • B42D25/405—Marking
  • B42D25/43—Marking by removal of material
  • B42D25/435—Marking by removal of material using electromagnetic radiation, e.g. laser
• • 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
  • B42D25/20—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof characterised by a particular use or purpose
  • B42D25/21—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof characterised by a particular use or purpose for multiple purposes
• • 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
• • B42D2035/20—
• • B42D2035/44—
• • 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

Definitions

• the invention relates to an optically variable security element for security papers, documents of value and other data carriers having a substantially transparent carrier with opposing first and second major surfaces, arranged on the first main surface of the carrier arrangement of microlenses and disposed on the second main surface of the carrier laser-sensitive recording layer.
• the invention also relates to a method for producing such a security element and to a data carrier having such a security element.
• Data carriers such as valuable documents or ID documents, but also other valuables, such as branded articles, are often provided with security elements for the purpose of security, which permit verification of the authenticity of the data carrier and at the same time serve as protection against unauthorized reproduction.
• Security elements with viewing-angle-dependent effects play a special role in the authentication of authenticity since they can not be reproduced even with the most modern copying machines.
• the security elements are thereby equipped with optically variable elements that give the viewer a different image impression at different viewing angles and, for example, show a different color or brightness impression and / or another graphic motif depending on the viewing angle.
• ID cards such as credit cards or identity cards have long been personalized by laser engraving.
• personalization by laser engraving the optical properties of the substrate material are irreversibly changed by suitably guiding a laser beam in the form of a desired marking.
• a laser k ist makes it possible to combine the individualization of the data carriers with security elements and to integrate them more freely into the printed image than in the case of conventional individualizations, for example in the case of known indexing methods.
• the document EP 0 219 012 A1 describes an identification card with a partial lenticular structure. This lens structure inscribes information into the card at different angles with a laser. This information can then also be recognized only at this angle so that the different information appears when tilting the map.
• the object of the invention is to specify a security element of the type mentioned at the outset with an attractive visual appearance and high security against counterfeiting.
• the microlens array is provided with a laser-sensitive covering layer which has at least one recess produced by the action of laser radiation which extends over a plurality of microlenses, the laser-sensitive recording layer has a multiplicity of has micro-characteristics generated by the action of laser radiation, wherein each micro-tag is associated with a microlens and is visible when viewing the security element through the associated microlens, and - the plurality of micro-indicia on the carrier is accurately positioned immediately opposite the at least one recess.
• Microlenses are lenses whose size is below the resolution limit of the naked eye.
• the microlenses are preferably spherical or aspherical and have, for example, banknotes with advantage a diameter between 5 ⁇ and 100 ⁇ , preferably between 10 ⁇ and 50 ⁇ , more preferably between 15 ⁇ and 20 ⁇ ⁇ .
• the microlenses may also be larger and, for example, have a diameter between 100 ⁇ and 300 ⁇ .
• the microlenses can also be designed as cylindrical lenses.
• the recess or the recesses form in all embodiments with advantage a motif in the form of patterns, characters or a coding.
• the recesses are preferably visible to the naked eye and in particular have a dimension between 0.5 mm and 3 cm.
• the distance between the cover layer and the recording layer is given by the thickness of the support and substantially corresponds to the focal length of the uncoated microlenses.
• the micro-marks are formed by micro-holes in the recording layer, in particular by substantially circular micro-holes or by pattern-shaped micro-holes.
• the exact form of the micro-markings or microholes depends in particular on derm from the shape of the microlenses (spherical, aspherical, cylindrical) and, as described below, also the angle of incidence of the laser radiation.
• the micro-indicia may also be in blackened or darkened changes in the visual appearance of the recording layer.
• the micro-marks may be formed by a color change or removal of the laser-sensitive recording layer.
• the removal of the laser-sensitive on-drawing layer also includes only a partial removal, which optically corresponds to a brightening.
• the color change or removal of the recording layer may be due to thermal, photochemical or mixed processes.
• the microdischarges In order to produce transmitted light effects, the microdischarges have a reduced opacity and are formed in extreme cases by said microholes. For incident light effects, a reduced opacity is not absolutely necessary, where the change may, for example, also consist in a blackening.
• the micro-flags are each smaller than the associated microlenses. The area ratio of
• Micro-tag and associated microlens are below 1.0 or below 0.5, below 0.2, or even below 0.1.
• Circular microholes for example, have a diameter between 1 ⁇ and 15 ⁇ ⁇ , between 1.5 ⁇ and 5 ⁇ ⁇ , and in particular between 2 ⁇ and 3 ⁇ ⁇ have.
• the security element is semitransparent in the area of the recesses and the opposing microviscosity, in particular with a light transmission between 20% and 90%.
• the light transmission of the security element is in any case significantly higher in the area of the recesses than in the areas still provided with the covering layer, which are typically opaque or have a light transmittance of less than 15%, in particular less than 10%.
• the security element has a conspicuous see-through effect, as described in more detail below.
• the microdischarges are introduced in preferred embodiments of at least two different directions with laser radiation through the Mikrolins senanssen into the recording layer.
• the micro-markers are then each substantially recognizable from the viewing directions under which they were introduced in the generation.
• the micro-identifiers can be recognized from at least two different viewing directions, so that tilting or alternating images can be generated.
• the visible from different viewing directions motifs can be in a sense and, for example, as in a flip book represent a sequence of images that runs when tilting the security element in front of the eye of the beholder. If a certain proportion of the motifs remain unchanged at all viewing angles, this area can also be implemented as a gap area in the recording layer.
• the insertion angle and thus also the viewing angle can also vary continuously over the extent of a recess, with variations in one or in two spatial directions being considered.
• the degree of transparency changes and thus the brightness in transmitted light continuously with the viewing angle, as described in more detail below.
• the cover layer in addition to the recesses produced by the action of laser radiation, also has gap regions which extend over a plurality of microlenses and which are not in the register with directly opposite microdischarges.
• Such gap regions can be generated, for example, before the generation of the micro-markings by a large-area removal of the covering layer, for example by a washing process or an etching process.
• the recesses in this variant of the invention form a first motif in the form of patterns, characters or a coding.
• further micro-codes produced by the action of laser radiation in the recording layer which form a second motif in the form of patterns, characters or a coding.
• These further micro-identifiers are each associated with a microlens, are preferably smaller than the associated microlenses and are visible when the security element is viewed through the associated microlens. They may also have the further properties mentioned for the first micro-license plates, in particular with regard to the shape and size of the micro-license plates.
• the recording layer has, in addition to the micro-marks produced by the action of laser radiation, gaps whose dimensions are greater than the dimension of the microlenses and which are not in the register with directly opposite recesses.
• gaps whose dimensions are greater than the dimension of the microlenses and which are not in the register with directly opposite recesses.
• Such gap areas in the drawing layer can also be generated, for example, by a washing process.
• first motif in the form of patterns, characters or an encoding
• second motif in the form of Patterns, signs or a coding.
• both the first and the second motif are recognizable and the two motifs complement each other to form an overall motif.
• the first motif is not recognizable in incident light, for example when the cover layer and the recording layer are chosen to be the same color.
• the cover layer has, in addition to the Ausspa- generated by the action of laser radiation. gaps which extend over several microlenses and which are not in the register with directly opposite microidentifiers. Immediately opposite to these gap areas of the cover layer congruent gap areas are provided in the recording layer.
• the gap areas in the cover layer and the recording layer are thereby advantageously produced by laser application simultaneously by the same laser steel. For this purpose, compared to the production of microholes described elsewhere, the laser energy is increased so much that not only the covering layer but also the recording layer is completely removed.
• the recesses form a first motif in the form of patterns, characters or a coding
• the gap regions of the covering layer form a second motif in the form of patterns, characters or an encoding.
• the security element also contains a micro-optical representation arrangement, in particular a moiré magnification arrangement, a moiré-type micro-optical magnification arrangement or a modulo magnification arrangement.
• the recording layer preferably contains, in addition to the microdischarges, a motif image which is divided into a plurality of cells, in each of which imaged areas of a predetermined third motif are arranged, wherein the microlens array forms a microlens grid that, upon viewing the motif image, reconstructs the third motif from the imaged areas located in the cells.
• the recording layer, the cover layer or both layers are opaque.
• the recording layer and / or the cover layer can be formed by an opaque metal layer or contain an opaque metal layer.
• the term metal also includes metal alloys. As opaque metal layers, for example, layers of aluminum, copper, chromium, silver, gold or an Al-Cu alloy into consideration.
• aluminum is selected as the material for the covering layer and copper as the material for the recording layer.
• the cover layer and the recording layer should appear to be the same color. In this case, the same material or color-like materials are chosen for both layers.
• thin-layer elements with a color-shift effect are also suitable for the cover layer and the recording layer.
• Such thin-film elements typically consist of an absorber layer, a dielectric spacer layer and a metallic reflector layer.
• the reflector layer is made thin enough so that it can be provided by the laser radiation with the desired recesses or micro holes.
• the recording layer, the cover layer or both layers are semitransparent, preferably each with a light transmission between 20% and 90%, in particular between 40% and 80%.
• the recording layer, the covering layer or both layers are formed by a laser-sensitive ink layer.
• the said possibilities can also be combined with one another, that is to say, for example, the recording layer can be formed by a laser-sensitive ink layer and the covering layer can be formed by an opaque metal layer.
• the covering layer is a transparent layer which changes the radius of curvature of the microlenses by at least 50%, in particular a transparent layer which levels the microlenses.
• the recording layer can be opaque or semitransparent in this variant of the invention.
• the refractive index of the transparent layer is expediently of the order of magnitude of the refractive index of the microlenses and in particular differs therefrom by less than 0.3, preferably by less than 0.15.
• the microdischarges are formed by microholes in the recording layer and that a reflection layer or a print layer is arranged on the recording layer.
• the microholes advantageously have a somewhat larger diameter of more than 5 ⁇ m, in particular of more than 10 ⁇ m.
• the reflective layer or the print layer on no micro-holes shows in reflected light a tilting image in which the motif formed by the plurality of microholes from a certain viewing angle in reflection or reflected light is visible and disappears when tilting the security element.
• the invention further comprises a data carrier, in particular a value document, such as a banknote, a passport, a document, an identity card or the like, which is equipped with a security element of the type described.
• a data carrier in particular a value document, such as a banknote, a passport, a document, an identity card or the like, which is equipped with a security element of the type described.
• the security element may be arranged in an advantageous variant of the invention, in particular in or over a window area or a through opening of the data carrier.
• the data carrier contains a data carrier substrate which has a marking region produced by the action of laser radiation, which adjoins at least one of the cutouts of the security element produced by laser radiation and is in register therewith.
• the marking area the visual appearance of the data carrier substrate is changed.
• color components or metallic substances can be removed from the data carrier substrate by the action of the laser radiation, or the data carrier substrate can be foamed. In the latter case, a visual mark is added to visually change the appearance. Due to the adjusted arrangement of recess and marking area, the security element is connected in a visually and optionally also mechanically detectable manner closely with the data carrier.
• the registered arrangement is made possible by the creation of recess and marking area in the same operation with the same laser beam.
• the data carrier thus connected to the security element has an increased security against counterfeiting, since the security element, after a detachment from the Disk can not be re-fit. A manipulation of the data carrier is therefore readily apparent to non-professionals.
• the recess and the marking area can in particular together form a total information, such as a contiguous graphical representation or a continuous alphanumeric character string.
• the security element is semitransparent depending on the direction of view, so that the part of the total information lying in the recess is only visible from certain angles.
• the part of the total information lying in the marking area of the data carrier substrate is always visible. When tilting the data carrier therefore only a part of the total information is visible from some points of view, which complements the complete total information from other points of view.
• the invention further includes a method for producing an optically variable security element for security papers, documents of value and other data carriers, in which a substantially transparent carrier is provided with opposite first and second main surfaces, wherein an arrangement of microlenses is arranged on the first main surface of the carrier.
• a laser-sensitive recording layer is arranged on the second main surface of the carrier, the microlens arrangement is provided with a laser-sensitive covering layer, at least one recess is produced in the laser-sensitive covering layer by the action of laser radiation, which extends over a plurality of microlenses, - in the laser-sensitive recording layer by the action of laser radiation, a multiplicity of micro-registration marks is produced, each micro-identification being assigned to a microlens and when viewing the security element is visible through the associated microlens, and the plurality of micro-mark on the support is arranged in register exactly opposite the at least one recess.
• micro-indices may each be made smaller than the associated microlenses.
• the micro-markings are generated from at least two different directions through the microlens array in the on-drawing layer.
• the invention also includes a method for producing a data carrier of the above type, in which a data carrier substrate is provided, a substantially transparent support is provided with opposing first and second major surfaces, wherein on the first main surface of the support an array of microlenses is arranged, on the second main surface of the support a laser-sensitive recording layer is provided, the microlens array is provided with a laser-sensitive cover layer Carrier with the laser-sensitive recording layer, the microlens array and the laser-sensitive cover layer is applied to the data carrier substrate, and in the same operation by the same laser beam by the action of laser radiation a) in the laser-sensitive cover at least one recess is formed, which extends over several microlenses, b In the laser-sensitive recording layer, a multiplicity of micro-marks are produced, each micro-tag being assigned to a microlens and, when viewing the security element
• color components or metallic substances are preferably removed from the data carrier substrate in the marking region or the data carrier substrate is foamed.
• the generation of the recess and of the plurality of micro-labels is carried out with a first set of laser parameter sets, and the generation of the marking region is performed with a second, different set of laser parameter sets.
• a process management takes into account the fact that the generation of the recesses and micro-labels may require different laser parameters, for example a laser energy of different intensity, than the generation of the marking region.
• the laser parameters of the laser beam are thereby switched over between the first and second laser parameter set at the locations where the marking area adjoins a recess of the covering layer. This switching can take place practically instantaneously, so that a precisely defined change of the laser parameters is achieved. Due to the uninterrupted beam guidance, despite the variation of the laser parameters, a matched arrangement of recess and marking area is achieved.
• FIG. 1 shows a schematic representation of a banknote with an optically variable security element according to the invention, which is arranged above a continuous opening of the banknote
• FIG. 2 shows schematically the layer structure of a security element according to the invention in cross-section
• FIG. 4 shows the visual appearance of the security element of FIG.
• FIG. 5 shows the visual appearance of the security element of FIG.
• Fig. 6 shows an embodiment in which the laser radiation in the
• 7 shows a further embodiment of the invention in cross section along the line VII-VII of FIG. 8 (a)
• 7 shows the visual appearance of the security element of FIG. 7 when viewed from the front, in (a) in incident light and in (b) in transmitted light
• 9 shows the visual appearance of the security element of FIG. 9, in (a) viewed from the front in incident light, (b) when viewed from the same side in transmitted light, in (c) viewed from the rear in reflected light, in FIG (d) when viewed from the same side in transmitted light, in (a) to (d) a representation as in Fig. 10 for a modification of the security element of Fig.
• a security element according to the invention which also forms a micro-optical representation arrangement, an embodiment of the invention, in which the cover layer is formed by a laser-sensitive transparent coating, an embodiment in which pattern-shaped micro holes in the Aufze be generated in (a) and (b) respectively a plan view of a recording layer with patterned micro holes according to embodiments of the invention, a further embodiment of the invention in cross section,
• FIG. 17 shows the visual appearance of the security element of FIG.
• Fig. 18 shows another embodiment of the invention, a
• FIG. 1 shows a schematic illustration of a banknote 10 with an optically variable security element 12 according to the invention, which is arranged above a continuous opening 14 of the banknote 10.
• the security element 12 appears semitransparent in partial regions 16 in transmitted light and, due to its application over the opening 14, can be viewed both from its front side and from its rear side in reflected light as well as in transmitted light.
• the security element 12 shows different visual appearances from these different viewing directions, as explained in more detail below.
• FIG. 2 shows schematically the layer structure of the security element 12 according to the invention in cross section, wherein only the parts of the layer structure required for the explanation of the functional principle are shown.
• the security element 12 contains a substantially transparent carrier.
• ger 20 which is typically formed by a transparent plastic film, for example, about 20 ⁇ thick polyethylene terephthalate (PET) film.
• PET polyethylene terephthalate
• the carrier 20 has opposing first and second major surfaces, the first major surface 22 being provided with an array of microlenses 26.
• the microlenses 26 are regularly arranged in the form of a microlens grid and form on the surface of the carrier film a two-dimensional Bravais grid with a preselected symmetry.
• the Bravais lattice of the microlenses 26 may, for example, have a hexagonal lattice symmetry or also a lower symmetry, such as the symmetry of a parallelogram lattice.
• the spherically or aspherically configured microlenses 26 preferably have a diameter between 15 ⁇ m and 30 ⁇ m, and are therefore invisible to the naked eye.
• the thickness of the carrier 20 and the curvature of the microlenses 26 are matched to one another such that the focal length of the microlenses 26 substantially corresponds to the thickness of the carrier 20.
• the microlens grid of the first main surface 22 is provided with an opaque, laser-sensitive cover layer 28, which is formed in the embodiment by a 50 nm thick aluminum layer.
• one or more recesses 30 were introduced by the action of laser radiation, which form a first motif in the form of patterns, characters or a coding.
• the recesses 30 extend over several, typically even over several thousand send microlenses 26, since the recesses 30 are visible to the naked eye and therefore typically have dimensions of several millimeters.
• the security element 12 described with reference to FIGS. 1 to 5 shows only a single recess 30 with the shape of a maple leaf 16. For example, if the recess 30 has an area of 50 mm 2 , it extends at a lens diameter of 25 ⁇ m over about 80,000 to 100,000 microlenses. It is therefore understood that the size ratios of microlenses and recesses in the figures can only be greatly exaggerated.
• a laser-sensitive recording layer 32 is arranged, which is formed in the embodiment by a 60 nm thick copper layer.
• the on drawing layer 32 has been introduced by the action of laser radiation a plurality 34 of circular micro holes 36 having a diameter of 2 ⁇ to 3 ⁇ .
• the recesses 30 and the opposing microholes 36 are generated simultaneously in the same operation and by the same laser beam in the same operation as described in more detail below, so that the recesses and the microholes have no tolerance to each other.
• the multiplicity 34 of the microholes in the recording layer 32 is thereby arranged on the carrier 20 in register, directly opposite the recesses 30 of the cover layer 28.
• the microlens grid present on the carrier 20 is first coated with a continuous, 50 nm-thick aluminum layer 28, as shown in FIG. 3 (a).
• the second main surface 24 is coated with a continuous, 60 nm thick copper layer 32. At these layer thicknesses, both the aluminum layer 28 and the copper layer 32 are opaque.
• the microlenses 26 in the coated areas are no longer effective optically.
• the thus coated carrier 20 is then exposed from the side of the first main surface 22 ago with laser radiation 40, for example, with the radiation of a Nd: YAG, Nd: YVO 4 - or fiber laser applied and the aluminum layer 28 in the form of desired recesses 30.
• the laser beam 40 can be pre-focused. The removal of the aluminum layer 28 restores the optical effectiveness of the microlenses 26 in the region of the recesses 30.
• a laser energy which is higher than the energy required for demetallizing the aluminum sheath 28 is used during the laser application, a residual energy remains after the ablation, which is then focussed onto the recording layer 32 f by the now optically effective microlenses 26, as indicated in Fig. 3 (b) by the reference numeral 42.
• the residual energy is not so high that the recording layer 32 is completely removed below the microlenses 26, but is sufficient to produce microholes 36 in the recording layer 32 whose dimensions are smaller than those of the associated microlenses 26 are.
• each of the microholes 36 is associated with a microlens 26, by which the micro-hole 36 is generated when exposed to laser, and by the micro-hole 36 at the later Viewing the security element is visible.
• the multiplicity 34 of the micro-holes 36 are thus produced with register accuracy and exclusively in the region of the respectively opposite recesses 30.
• the area of the recesses 30 from the normal viewing distance of 20 to 30 cm is congruent with the area 34 provided with the plurality of micro-holes 36.
• FIG. 4 shows the visual appearance of the security element 12 thus produced when viewed from the side of the first main surface 22 (front side), FIG. 4 (a) showing the appearance in incident light, ie in reflection, and FIG. 4 (b) FIG. the appearance in transmitted light, ie in transmission shows.
• the silvery shining cover layer 28 of aluminum dominates the appearance.
• the cover layer 28 is removed and the viewer sees there the copper color of the recording layer 32.
• the micro-holes 36 in the recording layer 32 are not or only with difficulty detectable in the reflected light because of their small size with the naked eye, so that the Recording layer 32 appears as a continuous metal layer.
• the security element 12 appears outside the recess 30 because of the opaque cover layer 28 dark.
• the recording layer 32 is semitransparent through the plurality 34 of the microholes 36 depending on the direction of view. Since the microholes 36 in this viewing direction through the microlenses 26th The microholes 36 are each seen substantially from the viewing angle at which they were introduced during generation by the laser beam 40. Moreover, around this central viewing angle, the microholes 36 can be seen in a certain angular range, which depends mainly on the diameter of the microholes 36. This in turn results in particular from the lens properties, in particular from the focal length of the microlenses at the laser wavelength, the thickness of the carrier 20, the laser energy used and the layer thickness of the recording layer 32. By suitable choice and tuning of these parameters, the diameter of the
• Micro holes 36 and thus adjust the angular extent of the visibility range in a wide range as desired.
• the microholes 36 of the described embodiment were generated under normal incidence of the laser radiation 40 as shown in FIG.
• the microholes 36 are therefore also visible when the security element 12 is viewed vertically through the microlenses 26, so that the region of the recess 30 appears semitransparent from this viewing angle in the transmitted light.
• the viewer then sees a bright maple leaf 16 against a dark background, as illustrated in Figure 4 (b).
• Figure 5 shows the visual appearance of the security element 12 as viewed from the side of the second major surface 24 (back), with Figure 5 (a) illustrating the appearance in reflected light and Figure 5 (b) illustrating the appearance in transmitted light.
• the security element 12 appears outside the recess 30 because of the opaque on drawing layer 32 dark.
• the recording layer 32 appears to be semitransparent through the plurality 34 of the microholes 36 in a wide angular range. In contrast to viewing from the front side, the microholes 36 are not viewed through microlenses 26 in the rear-side view.
• the microlenses 26 collect the light incident from the first major surface 22 and focus it on the microholes 36 to provide a wide range of angles below which microholes 36 appear bright on the back surface. The viewer thus sees a bright maple leaf 16 against a dark background, as illustrated in Fig. 5 (b).
• the microholes have been introduced into the recording layer only from a single direction, namely, from a direction perpendicular to the major surfaces 22, 24.
• the microholes of security elements according to the invention are produced from at least two different directions through the microlens grid in the recording layer.
• FIG. 6 shows an exemplary embodiment in which the laser radiation 40 encloses an angle ⁇ with the vertical 44 when a recess 30 'is produced.
• the recess 30 ' virtually indistinguishable from a recess 30 formed under perpendicular loading, but the microholes 36' produced in the recording layer 32 are shifted out of the center of the lens.
• a certain range of visibility results around the angle ⁇ , which is given by the size of the microholes 36 '.
• microholes 36 By creating microholes 36 with different viewing angles ⁇ , regions can thus be created which are semitransparent in transmitted light from respectively different angles, so that a tilted image is formed.
• the microholes 36, 36 'in this case within a recess 30, 30' each have a constant viewing angle ⁇ 30, ⁇ 3, while the viewing angles of different recesses 30, 30 'differ, ie ⁇ 30 Qw.
• the insertion angle and hence also the viewing angle ⁇ varies continuously over the extent of the recesses 30 in one or even in two spatial directions.
• Such a continuous change can for example be realized by a suitable deflection system for the laser radiation.
• the appearance of the semitransparency then changes continuously when viewed in transmitted light when tilting the security element within the recess 30.
• the front of the In the case of transmitted light the left side of the maple leaf 16 then appears very bright, since the observer sees the microholes 36 introduced therein at a right angle through the microlenses 26.
• the brightness decreases continuously towards the right edge of the maple leaf 16, since the microlenses 26 focus more and more on the edge or on outer areas of the microholes 36 as the angle ⁇ increases.
• the brightness decreases continuously towards the left edge of the maple leaf 16, since the microlenses 26 now focus more and more on the edge or outer regions of the microholes 36 as the angle ⁇ decreases.
• a further exemplary embodiment of the invention is illustrated schematically in cross-section in FIG. 7 and in FIG. 8 with its visual appearance in reflected light and transmitted light.
• the cover layer 28 in addition to the recesses 30 already described and produced by the action of laser radiation, has gap regions 52 which extend over a large number of microlenses, but which are not matched with directly opposite microholes 36. These gap regions 52 can, for example, be demetallised with a
• washing process before the laser application to produce the recesses 30 are generated.
• a soluble washing ink in the form of the desired Demetallmaschines Kunststoffes is preferably printed on the carrier 20 prior to metallization, and the washing paint after metallization washed with this by a solvent. Further details of such a washing process can be found in the publication WO 99/13157, the disclosure of which is incorporated in the present application in this respect.
• the gap area 52 occupies the lower half of the security element 50 as shown in FIG. 8 (a).
• the gap regions 52 can be formed in the form of random patterns, characters or codes.
• the recesses 30 now form a first motif, which in the exemplary embodiment shown is indicated by the upper half of the numerical sequence "10" (FIG. 8 (a))
• a multiplicity 54 of microholes 56 were also generated by laser application form a second motif, which is presently formed by the lower half of the digit sequence "10". Since a larger proportion of the laser energy arrives at the recording layer 32 in the gap region 52, the microholes 56 may have a slightly larger diameter than the microholes 36. In order to avoid this variation, the laser energy in the gap region 52 can be suitably reduced.
• FIG. 8 shows the visual appearance of the security element 50 thus produced viewed from the side of the first main surface 22.
• the silvery aluminum cover layer 28 determines the appearance.
• the cover layer 28 is removed and the viewer sees the copper color of the recording layer 32.
• the microholes 36 are due to Their small size in incident light with the naked eye is difficult or impossible to see, so that the drawing layer 32 appears as a continuous metal layer. The observer thus sees in the incident light only the upper half of the number sequence "10", as shown in Fig. 8 (a)
• the incomplete motif representation attracts attention and stimulates the observer to look through the view in order to see the complete motif "10 "to see.
• both the first motif of the recesses 30 and the second motif 54 then appear semitransparent, as a result of the microholes 36 and 56, depending on the viewing direction, as explained in connection with FIG. 4 (b).
• the security element 50 is opaque because the viewer is looking either at the opaque capping layer 28 or at the opaque coating layer 32 as well.
• the difference in color between the copper-colored recording layer 32 and the silver-colored cover layer 28 in the transmitted light strongly in the background and is not or hardly recognizable in the rule.
• the first motif 30 and the second motif 54 complement each other to form a bright overall motif in the form of the digit sequence "10" in front of a uniformly dark background, as illustrated in FIG. 8 (b).
• Gap regions 62 may also be provided in the recording layer 32 instead of in the cover layer 28, as shown in FIGS. 9 and 10. Illustrated that a security element according to the invention 60 schematically in cross-section and the visual appearance in front and rear side viewing in incident and transmitted light.
• the recording layer 32 has, in addition to the microholes 36 already described and produced by the action of laser radiation, gap regions 62 whose dimensions are greater than the dimension of the microlenses 26 and which are not matched with directly opposite recesses 30. These gap regions 62 may be generated, for example, by demetallizing with a washing process prior to the laser application to produce the microholes 36.
• the gap area 62 occupies the lower half of the security element 60 as shown in FIG. 10 (a).
• the upper half 64 of the security element 60 there is a recording layer 32.
• the gap regions 62 may be in the form of any patterns, characters or encodings.
• the security element 60 was subjected to laser radiation as described above, in order to simultaneously and precisely create recesses 30 in the cover layer 28 and microholes 36 in the imaging layer 32. In the gap regions 62, no additional microholes 36 can be created.
• the partial region 74 of the recesses 30 that lies above the recording layer 32 now forms a first motif, which is given by the upper half of the number sequence "10.”
• the partial region 72 of the recesses 30 that lies above the gap region 62 forms a second one Motif formed herein by the lower half of the digit string "10" (Fig. 10 (a)).
• Figure 10 shows the visual appearance of the security element 60 thus produced.
• the silvery aluminum cover layer 28 determines the appearance.
• the cover layer 28 is removed and the viewer sees there the copper color of the drawing layer 32.
• both cover layer 28 and recording layer 32 are removed, where the viewer sees the under security - selement 60 located underground.
• the first subregion 74 of the recesses 30 When viewing the front side in transmitted light (FIG. 10 (b)), the first subregion 74 of the recesses 30 then appear semitransparent, as described above, owing to the microholes 36 contained, depending on the viewing direction.
• the second portion 72 of the recesses 30 appears transparent, since there is no recording layer 32 there.
• the security element 60 in the upper half 64 in the partial region 74 of the recesses appears semitransparent through the multiplicity of microholes 36 in the recording layer 32 in a large angular range.
• the second portion 72 of the recesses 30 appears transparent because there is no recording layer 32 there.
• a silver-colored aluminum layer is selected as the recording layer 82 instead of the copper-colored recording layer 32 of FIG. 10, then the cover layer 28 and the recording layer 82 are almost identical in color.
• the first portions 74 of the recesses 30, in which the recording layer 82 is visible can not be distinguished from the surrounding cover layer 28, as shown in Fig. 11 (a). The viewer therefore only recognizes the lower half of the overall motif.
• the first motif of the first partial regions 74 then complements the second motif of the second partial regions 72 to form the complete digit sequence "10", as shown in FIG. 11 (b).
• the coating layer 82 and the cover layer 28 located outside the partial regions 72 of the recesses 30 appear in incident light with the same color, as shown in FIG. 11 (c). Therefore, the observer also recognizes only the lower half of the overall motif from the rear side. In transmitted light, the first motif of the first partial regions 74 then complements the second motif of the second partial regions 72 to form the complete digit sequence "10", as shown in FIG. 11 (d).
• the described effects can be combined with a micro-optical representation arrangement, in particular a moire magnification arrangement, a moiré-type micro-optical magnification arrangement or a modulo magnification arrangement, as illustrated in the exemplary embodiment of FIG. 12.
• the recording layer 92 of the security element 90 contains, in addition to the microholes 36 already described, a grid-like arrangement of micromotif elements 94.
• the arrangement of the micromotif elements 94 forms like the arrangement of the microlenses 26, a grid with a preselected symmetry, wherein the tuning of the microlens grid and the grid of Mikromo ivelemente 94 a desired moire magnification effect and characteristic motion effects are generated.
• the Bravais grating of the grating cells of the micromotile elements 94 differs slightly in its orientation and / or in the size of its grating parameters from the Bravais grating of the microlenses 26, as in FIG.
• Such security elements with microoptical representational arrangements also enable impressive motion effects, as explained in more detail in the above-cited document.
• the grid parameters of the arrangement of the imaged areas and of the microlens grid can be coordinated so that an orthoparallactic motion effect results when tilting the security element 90, in which the motif shown moves perpendicular to the tilting direction and not parallel to it, as one would intuitively expect.
• these moiré effects are visible only in the region of the recesses 30 or gaps 52 of the cover layer 28. If the same material or materials of the same color are selected for the covering layer 28 and the recording layer 92, then only the moiré effects are visible in the incident light in the regions 30, 52.
• the laser-sensitive cover layer and the laser-sensitive recording layer were each formed by opaque metal layers for illustration.
• the drawing layer may, for example, also be formed by a thin-film element with a color-shift effect, as indicated above.
• the cover layer and / or the drawing layer can also be semitransparent and in particular have a light transmission between 20% and 90%. If the covering layer 28 is semitransparent, for example, the moiré effect of FIG. 12 can also be seen outside the recesses 30 with reduced brightness. If both the covering layer 28 and the recording layer 32 are semitransparent, then the security element also has a certain residual transparency outside the recesses and gaps. This may be particularly advantageous if the security element is arranged above an opening 14 or a window area of a value document, as in FIG. Shape and outline of the opening 14 are then visible in transmitted light.
• the cover layer 28 may also be formed by a laser-sensitive transparent coating 100, as illustrated in FIG. 13.
• the coating 100 may be, for example, an IR lacquer which is substantially transparent in the visible spectral range, but which strongly absorbs the radiation of an infrared laser used for charging, for example the 1.064 ⁇ m radiation of a Nd: YVO 4 laser.
• the optical efficiency of the microlenses 26 can also be reduced by such a transparent coating by changing the radius of curvature of the lenses, for example by 50% or more.
• the transparent layer can level the lenses and completely cancel out the optical effect.
• the refractive index of the transparent coating 100 is expedient in the order of the refractive index of the microlenses 26th
• a further thin layer 102 can be provided between the leveling laser-sensitive coating 100 and the microlenses 26.
• This may be, for example, a coating that promotes detachment of the laser-sensitive coating 100.
• the further thin layer 102 may also be a reflective layer, for example an aluminum layer, so that the microlenses 26 outside the demetallized areas act as micro-hollow mirrors.
• pattern-shaped microholes 110 can also be produced instead of circular microholes during the laser application.
• the angle of incidence of the laser radiation 40, 40 'in the laser application is varied according to the desired shape of the patterned microhole 110.
• a demetallized line 110 can be generated in the recording layer 32.
• the shape of the recess 30 does not change.
• microholes may also be formed in the form of two-dimensional patterns 112 as shown in the plan view of the recording layer 32 of FIG. 15 (a).
• the shape of the Recess 30 not because at the location of the cover layer 28 only the angle of incidence, but not the position of the laser beam 40 varies.
• microdischarges 114 may also be generated in the plot layer 32, as illustrated in FIG. 15 (b).
• the color of the recording layer 32 may change due to the action of the laser radiation focussed by the microlenses 26.
• the angle of incidence of the laser radiation 40 By varying the angle of incidence of the laser radiation 40 in two spatial directions, it is thus possible within a recording layer 32 with a first color to produce microidentifiers 114 with a second color.
• other laser-sensitive materials may be considered in addition to the metal layers already mentioned, the visual appearance of which can be changed by the action of the laser radiation.
• the recesses 30 and the multiplicity of microdevices may contain an individualization of the security element, for example the serial number of a banknote 10.
• Such passivated individualizations can only be adjusted with difficulty using other methods and therefore have a high degree of protection against counterfeiting.
• the individualization of the security element can be combined in particular with the tilt images described in connection with FIG. For example, the introduced at a vertical angle
• Micro-flags represent a non-individualizing graphic motif.
• micro-markers are then introduced into the recording layer, which represent an individualization, for example the signature of a passport holder or a serial number.
• the security element changes the visible representation of the graphic motif when viewed vertically to the individualization in oblique view.
• a further embodiment of the invention is illustrated schematically in cross-section in FIG. 16 and in FIG. 17 with its visual appearance in incident and transmitted light.
• the cover layer 28 has, in addition to the recesses 30 already described, congruent gap regions 122, 124 generated in the cover layer 28 or in the recording layer 32 by the action of laser radiation.
• the laser energy has been increased to such an extent that not only the cover layer 28 but also the recording layer 32 beneath the microlenses 26 has been completely removed.
• the recesses 30 and the microholes 36 are produced at lower laser energy at which the residual energy after ablation of the capping layer 28 only results in the formation of the small microholes 26 in the recording layer 32.
• the gap regions 122 and the recesses 30 can connect to one another without transition and with register accuracy.
• the recesses 30 form a first motif which is given by a part of the digit sequence "50" indicated by the dashed outline in Fig. 17 (a)
• the gap regions 122 form a second motif passing through the remainder the number sequence "50" is given.
• FIG. 17 shows the visual appearance of the security element 120 thus produced viewed from the side of the first main surface 22.
• the cover layer 28 and the Recording layer 32 thereby from the same material, for example aluminum.
• the observer looks at the color-identical recording layer 32, so that the recesses 30 do not appear in reflected light due to the lack of contrast and because of the small size of the microholes 36.
• the incomplete motif presentation thus stimulates the observer to look at the transmitted light in order to be able to recognize the complete motif.
• the first motif of the recesses 30 When viewed in transmitted light then, as shown in Fig. 17 (b), the first motif of the recesses 30 appear semitransparent depending on the viewing direction, as explained above several times.
• the first and second motif complement each other to form a bright overall motif in the form of the numerical sequence "50" in front of a uniformly dark background
• a security element 130 according to another embodiment of the invention, wherein a reflection layer 132 made of aluminum, which contains no microholes, is arranged on a recording layer 32.
• the microholes 134 in the recording layer 32 are slightly larger than in the embodiments described above and, with a diameter of the microlenses of 30 ⁇ m, have a diameter of 5 to 15 ⁇ m
• the security element 130 shows a tilted image in the reflected light view From the viewing angle from which the microholes 134 were introduced, the observer looks through the microholes 134 on the silver-colored reflection layer 132 and thus sees the The motif formed by the microholes 134 is silver-colored in front of the copper-colored background of the recording layer 32. If the observer tilts the security element 130 into another viewing angle, only the copper-colored recording layer 32 is visible and the motif disappears.
• the layer 132 may also be a printed layer applied to the underlying substrate, such as a banknote paper.

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• 2011
  • 2011-11-04 DE DE102011117677A patent/DE102011117677A1/de not_active Withdrawn
• 2012
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  • 2012-11-05 AU AU2012331447A patent/AU2012331447B2/en not_active Ceased
  • 2012-11-05 WO PCT/EP2012/004600 patent/WO2013064268A1/de active Application Filing
  • 2012-11-05 CN CN201280065704.6A patent/CN104023991B/zh active Active
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