DE102017008919A1 - Value document and method for producing the same - Google Patents

Value document and method for producing the same

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Publication number
DE102017008919A1
DE102017008919A1 DE102017008919.1A DE102017008919A DE102017008919A1 DE 102017008919 A1 DE102017008919 A1 DE 102017008919A1 DE 102017008919 A DE102017008919 A DE 102017008919A DE 102017008919 A1 DE102017008919 A1 DE 102017008919A1
Authority
DE
Germany
Prior art keywords
effect pigments
method according
step
curing
particular
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.)
Pending
Application number
DE102017008919.1A
Other languages
German (de)
Inventor
Kai Scherer
Christian Fuhse
Michael Rahm
Maik Rudolf Johann Scherer
Raphael Dehmel
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
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Application filed by Giesecke and Devrient Currency Technology GmbH filed Critical Giesecke and Devrient Currency Technology GmbH
Priority to DE102017008919.1A priority Critical patent/DE102017008919A1/en
Publication of DE102017008919A1 publication Critical patent/DE102017008919A1/en
Application status is Pending legal-status Critical

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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B42BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
    • B42DBOOKS; 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
    • B42D25/00Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
    • B42D25/30Identification or security features, e.g. for preventing forgery
    • B42D25/36Identification or security features, e.g. for preventing forgery comprising special materials
    • B42D25/369Magnetised or magnetisable materials
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B05SPRAYING OR ATOMISING IN GENERAL; APPLYING LIQUIDS OR OTHER FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05DPROCESSES FOR APPLYING LIQUIDS OR OTHER FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D3/00Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
    • B05D3/06Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by exposure to radiation
    • B05D3/061Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by exposure to radiation using U.V.
    • B05D3/065After-treatment
    • B05D3/067Curing or cross-linking the coating
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B05SPRAYING OR ATOMISING IN GENERAL; APPLYING LIQUIDS OR OTHER FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05DPROCESSES FOR APPLYING LIQUIDS OR OTHER FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D3/00Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
    • B05D3/20Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by magnetic fields
    • B05D3/207Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by magnetic fields post-treatment by magnetic fields
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B05SPRAYING OR ATOMISING IN GENERAL; APPLYING LIQUIDS OR OTHER FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05DPROCESSES FOR APPLYING LIQUIDS OR OTHER FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D5/00Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures
    • B05D5/06Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures to obtain multicolour or other optical effects
    • B05D5/065Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures to obtain multicolour or other optical effects having colour interferences or colour shifts or opalescent looking, flip-flop, two tones
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B42BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
    • B42DBOOKS; 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
    • B42D25/00Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
    • B42D25/20Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof characterised by a particular use or purpose
    • B42D25/29Securities; Bank notes
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B42BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
    • B42DBOOKS; 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
    • B42D25/00Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
    • B42D25/30Identification or security features, e.g. for preventing forgery
    • B42D25/36Identification or security features, e.g. for preventing forgery comprising special materials
    • B42D25/373Metallic materials
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B42BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
    • B42DBOOKS; 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
    • B42D25/00Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
    • B42D25/30Identification or security features, e.g. for preventing forgery
    • B42D25/36Identification or security features, e.g. for preventing forgery comprising special materials
    • B42D25/378Special inks
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B42BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
    • B42DBOOKS; 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
    • B42D25/00Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
    • B42D25/30Identification or security features, e.g. for preventing forgery
    • B42D25/36Identification or security features, e.g. for preventing forgery comprising special materials
    • B42D25/378Special inks
    • B42D25/387Special inks absorbing or reflecting ultra-violet light
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B42BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
    • B42DBOOKS; 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
    • B42D25/00Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
    • B42D25/40Manufacture
    • B42D25/405Marking
    • B42D25/41Marking using electromagnetic radiation

Abstract

The invention relates to a method for producing a value document, in particular a banknote, comprising
a) providing a value document substrate;
b) printing the value document substrate with an ink based on magnetically orientable effect pigments or OVMI pigments;
c) while the printed ink is still liquid, orienting or aligning the magnetically orientable effect pigments by means of a first magnetic field;
d) the selective curing of the color matrix surrounding the magnetically oriented effect pigments by UV radiation or by laser radiation in a first region of the printed ink so that the effect pigments are immobilized in the aligned state, the curing having a resolution or a line width of less than 1 , 59 mm, preferably less than 800 microns, takes place.

Description

  • The invention relates to a method for producing a value document, in particular a banknote, and a document of value obtainable by the method.
  • Data carriers, such as valuables or identity documents, or 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 carriers 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 copiers. The security elements are thereby equipped with optically variable elements that give the viewer a different image impression under different viewing angles and, for example, show a different color or brightness impression and / or another graphic motif depending on the viewing angle.
  • Security features for securing value documents, in particular banknotes, which contain magnetically orientable effect pigments are known in the prior art. Magnetically orientable effect pigments are e.g. commercially available under the trade name OVMI® from SICPA (the abbreviation OVMI stands for the term "optically variable magnetic ink"). The pigments typically have a platelet-like structure and are in the form of a layer composite which often includes two layers of optical effect layers and a magnetic layer embedded therebetween. With respect to the optical effect layers, metallic reflecting layers as well as color shifting layer systems, e.g. with an absorber / dielectric / reflector structure, in question. The embedded magnetic layer is usually invisible, but is required to align the pigments.
  • The pigments dissolved in a printing ink are printed on a carrier substrate, for example banknote paper or a polymeric banknote substrate. Immediately after printing, the ink is still liquid, so that the platelet-shaped pigments within the color matrix surrounding the pigments are still freely movable. Subsequently, an external magnetic field is applied in which the pigments align themselves, the pigments typically being arranged parallel to the field lines due to the shape anisotropy. In this state, the color matrix surrounding the effect pigments is cured either by UV radiation or by the application of heat, so that the effect pigments are immobilized in the aligned state. For an observer arises in this way an optically variable effect, such as a light reflection that runs along the tilting direction when tilting the printing technology security element obtained. Depending on the applied magnetic field, various optically variable effects can be realized.
  • Based on the method described above, prior art magnetic ink areas can also be cured in two separate steps to realize more complex effects and / or image information. The 1 shows a paper substrate with a printable security feature based on OVMI pigments wherein selective cure is performed in two separate steps. In this case, the region (a) is selectively cured with a laser while applying a first magnetic field, while the remaining pigments in the region (b) remain freely movable. In this case, the selectively cured area can carry image information in the form of a border or projection. In the second step, the magnetic particle ink reaches a second magnet. The still freely moving particles in region (b) align themselves in the stray field of the second magnet and are subsequently cured by means of a UV flood exposure. According to the field lines of the first and the second magnet, the regions (a) and (b) now carry different orientations of the magnetic particles contained therein. This procedure is in the Scriptures EP 2 468 423 A1 described.
  • The EP 2 468 423 A1 describes the selective curing of a magnetic ink via the use of a laser or several lasers in the sense of an array, wherein the lasers are used either as focused or defocused point lasers or as line lasers. It describes resolutions ("projection of the laser beam") from 1.59mm to 9.5mm. Due to the very rough, minimal line width of 1.59 mm, there are inevitably disadvantages in terms of design choice. Thus, in the course of the laser treatment, only a very rough image information in the area (a) of 1 be introduced. Motives with fine weights can not be realized. Furthermore, the areas (a) and (b) of the 1 not nested effectively because this line widths of at most 200 microns, preferably less than 100 microns, more preferably less than 80 microns, are needed so that the individual lines are no longer visible to the human eye and the viewer gets the impression he sees a homogeneous picture. Accordingly, based on the state of the art so-called flip effects or overlapping pumping and running effects can not be realized.
  • Due to a finite number of laser sources can also be no large areas with different intensity distribution in the Cure single-shot process. Line-based and / or point-based curing limits the process speed.
  • Based on the above-cited prior art, the object of the invention is to provide an improved production method for a security feature based on magnetically orientable effect pigments. In particular, finer resolutions should be achieved.
  • This object is achieved on the basis of the feature combination defined in the independent claim.
  • Further developments of the invention are the subject of the dependent claims.
  • Summary of the invention
  • 1. (First aspect of the invention) A method for producing a value document, in particular a banknote, comprising
  1. a) providing a value document substrate;
  2. b) printing the value document substrate with an ink based on magnetically orientable effect pigments or OVMI pigments;
  3. c) while the printed ink is still liquid, orienting or aligning the magnetically orientable effect pigments by means of a first magnetic field;
  4. d) the selective curing of the color matrix surrounding the magnetically oriented effect pigments by UV radiation or by laser radiation in a first region of the printed ink so that the effect pigments are immobilized in the aligned state, the curing having a resolution or a line width of less than 1 , 59 mm, preferably less than 800 microns, takes place.
  • The resolution or line width refers to the projected pixel size or line width of the light source at the location of the ink printed on the value document substrate and based on magnetically orientable effect pigments or OVMI pigments.
  • The term "selective curing" is to be understood as meaning that a specific or selected area of the printed ink is cured, in particular in order in this way to produce a region with information content and / or a particular optically variable effect.
  • The UV radiation is preferably a directed UV radiation.
  • The value document substrate provided in step a) is in particular a paper substrate, a plastic substrate, a film / paper / foil composite substrate (see, for example, US Pat WO 2006/066431 A1 ) or a paper / foil / paper composite substrate (see eg WO 2004/028825 A2 ).
  • According to a variant, the value document substrate provided in step a) is a film substrate for producing security strips, security threads or security patches or security labels which are used to secure value documents, e.g. Banknotes that are suitable.
  • 2. (Preferred embodiment) Procedure according to paragraph 1 , additionally comprising
    • e) the step in which the resulting value document substrate is exposed to a second magnetic field deviating from the first magnetic field so as to orient non-immobilized, magnetically orientable effect pigments in a second region, which has not yet been irradiated, outside the first region of the printed ink or to align; and
    • f) the curing of the color matrix surrounding the magnetically oriented effect pigments in the second region of the printed ink by radiation, in particular UV radiation, so that the effect pigments are immobilized in the aligned state.
  • In step f), irradiation, in particular with UV light, can take place in particular over the whole area.
  • In particular, a value document substrate printed with magnetically orientable effect pigments can be provided in this way, which has a first optical effect (or first optically variable effect) in a first region of the print layer and a first optical effect (or first optical effect) in a second region of the print layer. first optically variable effect) deviating second optical effect (or second optically variable effect).
  • 3. (Preferred embodiment) Procedure according to paragraph 1 or 2 wherein the selective cure in step d) is accomplished by using an absorption mask or a micro-mirror actuator (DMD) or LCoS (Liquid Crystal on Silicon) technique or LCD or diffractive optical element (DOE) or lens array.
  • 4. (Preferred embodiment) Method according to one of the paragraphs 1 to 3 , wherein the selective curing in step d) takes place in a single-shot method.
  • In the single-shot method, a 2D array can be used. In particular, a 2D-DMD, an LCoS (Liquid Crystal on Silicon) technique or an LCD is used here.
  • 5. (Preferred embodiment) Method according to one of the paragraphs 1 to 4 wherein the selective cure in step d) is a line-based cure.
  • For line-based curing, a 1D array can be used. In particular, a 1D DMD, an LCoS (Liquid Crystal on Silicon) technique or an LCD is used here.
  • 6. (Preferred embodiment) Method according to one of the paragraphs 1 to 5 , wherein the selective curing in step d) takes place by means of an LCoS (liquid crystal on silicon) technique, in particular in reflection.
  • 7. (Preferred embodiment) Method according to one of the paragraphs 1 to 5 , wherein the selective curing in step d) takes place by means of an LCD.
  • 8. (Preferred embodiment) Method according to one of the paragraphs 1 to 5 , wherein the selective curing in step d) by using a diffractive optical element (DOE), in particular in conjunction with laser radiation occurs.
  • 9. (Preferred embodiment) Method according to one of the paragraphs 1 to 5 wherein the selective curing in step d) is effected by using a microlens array, in particular in conjunction with a directed UV (flood) exposure.
  • 10. (Preferred embodiment) Method according to one of the paragraphs 1 to 9 , wherein the selective curing of the color matrix surrounding the magnetically oriented effect pigments in step d), and optionally in step f), takes place in such a way that the effect pigments are immobilized in the aligned state and thus produce an optically variable effect.
  • The optically variable effect is e.g. a light reflection, which occurs when tilting the resulting value document along the tilting direction.
  • In the case where steps e) and f) are mandatory, two areas with different optically variable effects can be obtained.
  • 11. (Preferred embodiment) Method according to one of the paragraphs 1 to 10 , wherein by means of the selective curing of the color matrix surrounding the magnetically oriented effect pigments, image information in the form of characters or a coding, or in the form of a pattern, a border or a projection, is generated.
  • 12. (Preferred embodiment) Method according to one of the paragraphs 1 to 11 wherein, by means of the selective curing of the color matrix surrounding the magnetically oriented effect pigments, image areas are nested into each other, each having a resolution or a line width of less than 200 μm, preferably less than 100 μm and particularly preferably less than 80 μm.
  • The resolution or line width refers to the projected pixel size or line width of the light source at the location of the ink printed on the value document substrate and based on magnetically orientable effect pigments or OVMI pigments.
  • 13. (Second aspect of the invention) A value document, in particular a banknote, obtainable by the method according to one of the paragraphs 1 to 12 ,
  • The value document may further be in particular a paper banknote, polymer banknote or composite film banknote, or an identity card or a passport data page.
  • Detailed Description of the Preferred Embodiments
  • In the present specification, instead of the phrase "magnetically orientable effect pigments", the abbreviation OVMI pigments is used.
  • The invention relates to a method for partial or area hardening magnetic color, in which the intensity distribution of a strong UV lamp or a laser can be adjusted individually to harden the magnetic color in single-shot mode or in the mode of linear shutdown can and, preferably, allow resolutions of less than 1.6mm. For selective hardening, for example, in the 1 In particular, the following methods can be used 1 ) or 2) are used:
    • option 1 ) Use of an absorption mask.
    • option 2 ) Use of a micro-mirror actuator (so-called "Digital Micromirror Device", the abbreviation DMD is used hereinafter).
  • The micro-mirror actuator is a microelectromechanical device for dynamic Modulation of light. In particular, a surface light modulator can be used. Here, the modulation of the light takes place via a mirror matrix. In particular, one of the following may be used:
    • - LCoS ("Liquid Crystal on Silicon", translated into German: liquid crystals on [a] silicon [substrate]), especially in reflection;
    • - LCD or a liquid crystal display, in particular in transmission;
    • - DOE or a diffractive optical element;
    • - a lens array.
  • Further exemplary embodiments and advantages of the invention are explained below with reference to the figures, in the representation of which a representation true to scale and proportion has been dispensed with in order to increase the clarity.
  • Show it:
    • 1 a value document substrate, eg a paper substrate for producing banknotes, which is printed with an ink based on OVMI pigments, the curing of the printing layer taking place in two separate steps;
    • 2 the selective curing of a color layer with OVMI pigments, wherein the micromirror actuator (DMD, 2D array) reflects the incident radiation and generates a freely selectable intensity modulation on the substrate plane;
    • 3 a line-based, selective hardening of a color layer with OVMI pigments in the form of a circle by means of a 1D-DMD array, in which the mirrors continuously change their pitch as the substrate passes underneath;
    • 4 illuminating a 2D DOE with coherent radiation to cure the color layer with OVMI pigments according to the diffraction pattern;
    • 5 a DOE for generating a specific intensity modulation for image coding;
    • 6 a lens array in combination with a UV flood exposure for the checkerboard curing of a color layer with OMVI pigments.
  • One embodiment is based on the use of an absorption mask.
  • The simplest way to form a light beam is based on the use of a mask which is opaque with respect to the wavelength used. In the case of UV light, this may e.g. a metallic grid or a metallic form, in particular based on aluminum, chromium, iron or the like. The mask is coated in a suitable material thickness, in particular greater than 200 nm, onto a transparent substrate, e.g. Glass, applied.
  • The disadvantage of using a mask, however, is the diffraction effect under laser irradiation, which results in masking of the mask in the OVMI plane.
  • Another embodiment is based on the use of a micromirror actuator or DMD.
  • Typical parameters are about 4 million pixels with a diagonal of 0.7 inches.
  • A micro-mirror actuator is based on a mirror array, i. a matrix-like arrangement of individual elements, wherein each individual element includes a tiltable reflecting surface with an edge length of a few micrometers. Each micromirror can be controlled flexibly by the force of electrostatic fields. The orientation of each mirror can be changed within a second up to 5000 times.
  • Depending on the orientation of the mirror array, light from a strong UV lamp or a laser can be deflected or reflected in such a way that an image (in the sense of an intensity modulation) is projected in the plane of the magnetic ink and selectively cures there. In order to focus, reduce or enlarge the projection image, projection lenses or other optical means can additionally be used.
  • For implementation, both a single-shot method with a 2D DMD, which images the entire image in the plane, as well as a line-based hardening with a 1D DMD possible, in which the image is "written" line by line under continuous mirror change, while the substrate or OVMI paint passes under the DMD.
  • DMD and micromirror actuators ensure resolutions well below 1.6 mm and, with diameters of several centimeters, are larger than conventional OVMI-based, print-based security features. It would thus be conceivable to expose any OVMI pigment directly by means of a DMD without further optical means and thereby achieve line thicknesses in the micrometer range.
  • The 2 illustrates the selective cure of a color coat with OVMI pigments, where the micromirror actuator (DMD, 2D array) reflects the incoming radiation and is arbitrary Intensity modulation generated at the substrate level. Illustrated is the single-shot method. Optionally existing optics between the micromirror actuator and the color layer with OVMI pigments is not shown.
  • The 3 Figure 1 illustrates a line-based, selective cure of a color layer with OVMI pigments in the form of a circle by means of a 1D DMD array, in which the mirrors continuously change their pitch as the substrate passes underneath.
  • Another embodiment is based on the use of an LCoS ("Liquid Crystal on Silicon", translated into German: liquid crystals on [a] silicon [substrate]), in particular in reflection.
  • Typical parameters are a chip size with a diagonal of 15.5 mm, a picture size of 1920 × 1080 pixels, a reflectivity of 74% and a contrast ratio greater than 5000: 1.
  • In the same procedure, an LCoS can be used. This includes a silicon foil (acts as a reflector), a thin layer of liquid crystal based thereon, and a thin glass sheet. In contrast to the micromirrors of the DMD, in the case of the LCoS liquid crystal molecules are driven by an electrical voltage. The orientation of the latter determines whether or not light can successfully pass the polarizer again, i. whether light is reflected or absorbed by the LCoS. In contrast to the DMD, the LCoS requires polarized light and thus a higher output power of the light source. Again, a 1D design or a 2D design of the chip is possible.
  • Furthermore, an LCoS can be used not only in reflection but also in transmission.
  • Another embodiment is based on the use of an LCD or a liquid crystal display, in particular in transmission.
  • An LCD, in contrast to LCoS, has two polarizers and is transmitted in transmission, i. without reflection layer, operated. According to the orientation of the liquid crystal, it changes the polarization of the light and decides whether or not light can pass through the second polarizer.
  • LCD, LCoS and DMD are electronic "switchable" masks, so to speak.
  • Another embodiment is based on the use of a diffractive optical element (DOE).
  • Diffractive optical elements are glass substrates to which microstructures are applied by lithographic techniques. Through different optical path lengths (in particular by height variations or by refractive index variations) of the sub-beams, phase modulations occur in them, resulting in interference patterns which generate amplitude modulations by constructive and destructive superimposition. Thus, by skillful design, the intensity patterns of a laser beam - after transmission through the DOE - manipulate and the beam can be shaped accordingly. In this case, high-quality DOEs have high transmission values and efficiency values, i. they only slightly reduce the power of the input intensity.
  • According to the design of the DOE many ways of curing can be realized:
    1. a) Pointed, periodic diffraction pattern for interleaving a region (a) and a region (b) by the use of 2D gratings (see 4 showing the illumination of a 2D DOE with coherent radiation to cure the color layer with OVMI pigments according to the diffraction pattern).
    2. b) Diffraction images of individualized form for curing a region (a) in appropriate form (see 5 showing a DOE for generating a specific intensity modulation for image coding).
    3. c) 1D grid for generating line screens. The 1D grid can be designed, for example, so that the diffraction pattern corresponds to a line grid parallel to the web direction or substrate direction, which allows a continuous curing process.
  • Another embodiment is based on the use of a microlens array.
  • With the help of a microlens array, in combination with a directed UV flood exposure, a fast, large area and locally selective curing of the magnetic ink can be achieved. So, for example, Under normal incidence, each microlens illuminates the incident light at a point below the lens plane. With periodic arrangement of the lenses, a checkerboard-like curing of the magnetic ink could thus be realized. Furthermore, 1D lenticular screens (e.g., cylindrical lenses) can be used to create line-like cured areas that would allow for continuous illumination.
  • In general, variable grids can be generated when illuminating a lens array by the size and / or the distances and / or the shape and / or or the regularity of the individual lenses is varied.
  • The 6 shows a lens array in combination with a UV flood exposure for the checkerboard curing of a color layer with OMVI pigments.
  • The method according to the invention offers numerous advantages over the prior art. In the prior art, various optical effects are known, which can be achieved by means of magnetic alignment of pigments and subsequent radiation curing. Also known is the possibility of combining several different effects by selective radiation curing. So far, however, only macroscopic surfaces (namely with a resolution greater than 1.6 mm) can be used for such combinations. In order to visualize different effects simultaneously and at the same location, however, many microscopic surfaces (in particular with a resolution of less than 200 μm) must be combined (or "nested") with one another, so that no disturbing rasters are visible. This is possible when using one or more of the techniques described herein. For example, flip effects can be realized where some effect is visible from one viewing angle area on the whole footprint of the security feature, and another effect is visible from another viewing angle area on the whole footprint of the security feature. Also, various motion effects can be seamlessly combined.
  • The nesting mechanism works as follows:
  • Below the resolution limit of the eye, a certain proportion of the OVMI area - in the form of a checkerboard pattern or line pattern - is given an effect (a).
  • This effect (a) is only at a viewing angle of e.g. 45 ° to see. The remaining free area is occupied with an effect (b) which is only at an angle of e.g. -45 ° can be seen. With the human eye, the rasterization or interleaving of the two effects is not recognizable. Now, for the viewer, the effect (a) appears over the entire surface at 45 ° and the effect (b) over the entire surface at below -45 °.
  • QUOTES INCLUDE IN THE DESCRIPTION
  • This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.
  • Cited patent literature
    • EP 2468423 A1 [0005, 0006]
    • WO 2006/066431 A1 [0015]
    • WO 2004/028825 A2 [0015]

    Claims (13)

    1. Method for producing a value document, in particular a banknote, comprising a) providing a value document substrate; b) printing the value document substrate with an ink based on magnetically orientable effect pigments or OVMI pigments; c) while the printed ink is still liquid, orienting or aligning the magnetically orientable effect pigments by means of a first magnetic field; d) the selective curing of the color matrix surrounding the magnetically oriented effect pigments by UV radiation or by laser radiation in a first region of the printed ink so that the effect pigments are immobilized in the aligned state, the curing having a resolution or a line width of less than 1 , 59 mm, preferably less than 800 microns, takes place.
    2. Method according to Claim 1 additionally comprising e) the step of exposing the resulting value document substrate to a second magnetic field deviating from the first magnetic field so as to include non-immobilized, magnetically orientable effect pigments in a second unexposed area outside the first area of the printed image Orient or align printing ink; and f) curing the color matrix surrounding the magnetically oriented effect pigments in the second region of the printed ink by radiation, in particular UV radiation, so that the effect pigments are immobilized in the aligned state.
    3. Method according to Claim 1 or 2 wherein the selective cure in step d) is accomplished by using an absorption mask or a micro-mirror actuator (DMD) or LCoS (Liquid Crystal on Silicon) technique or LCD or diffractive optical element (DOE) or lens array.
    4. Method according to one of Claims 1 to 3 , wherein the selective curing in step d) takes place in a single-shot method.
    5. Method according to one of Claims 1 to 4 wherein the selective cure in step d) is a line-based cure.
    6. Method according to one of Claims 1 to 5 , wherein the selective curing in step d) takes place by means of an LCoS (liquid crystal on silicon) technique, in particular in reflection.
    7. Method according to one of Claims 1 to 5 , wherein the selective curing in step d) takes place by means of an LCD.
    8. Method according to one of Claims 1 to 5 , wherein the selective curing in step d) by using a diffractive optical element (DOE), in particular in conjunction with laser radiation occurs.
    9. Method according to one of Claims 1 to 5 wherein the selective curing in step d) is effected by using a microlens array, in particular in conjunction with a directed UV (flood) exposure.
    10. Method according to one of Claims 1 to 9 , wherein the selective curing of the color matrix surrounding the magnetically oriented effect pigments in step d), and optionally in step f), takes place in such a way that the effect pigments are immobilized in the aligned state and thus produce an optically variable effect.
    11. Method according to one of Claims 1 to 10 , wherein by means of the selective curing of the color matrix surrounding the magnetically oriented effect pigments, image information in the form of characters or a coding, or in the form of a pattern, a border or a projection, is generated.
    12. Method according to one of Claims 1 to 11 wherein, by means of the selective curing of the color matrix surrounding the magnetically oriented effect pigments, image areas are nested into each other, each having a resolution or a line width of less than 200 μm, preferably less than 100 μm and particularly preferably less than 80 μm.
    13. Security document, in particular a banknote, obtainable by the method according to one of Claims 1 to 12 ,
    DE102017008919.1A 2017-09-22 2017-09-22 Value document and method for producing the same Pending DE102017008919A1 (en)

    Priority Applications (1)

    Application Number Priority Date Filing Date Title
    DE102017008919.1A DE102017008919A1 (en) 2017-09-22 2017-09-22 Value document and method for producing the same

    Applications Claiming Priority (2)

    Application Number Priority Date Filing Date Title
    DE102017008919.1A DE102017008919A1 (en) 2017-09-22 2017-09-22 Value document and method for producing the same
    EP18000744.5A EP3459758A1 (en) 2017-09-22 2018-09-19 Valuable document, method for producing same and printer

    Publications (1)

    Publication Number Publication Date
    DE102017008919A1 true DE102017008919A1 (en) 2019-03-28

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    DE (1) DE102017008919A1 (en)

    Citations (3)

    * Cited by examiner, † Cited by third party
    Publication number Priority date Publication date Assignee Title
    WO2004028825A2 (en) 2002-09-19 2004-04-08 Giesecke & Devrient Gmbh Security paper
    WO2006066431A1 (en) 2004-12-23 2006-06-29 Landqart Multilayer structure as a printing substrate, and method for the production thereof
    EP2468423A1 (en) 2010-12-27 2012-06-27 JDS Uniphase Corporation System and method for forming an image on a substrate

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    Publication number Priority date Publication date Assignee Title
    US6808806B2 (en) * 2001-05-07 2004-10-26 Flex Products, Inc. Methods for producing imaged coated articles by using magnetic pigments
    TWI487628B (en) * 2008-11-24 2015-06-11 Sicpa Holding Sa Magnetically oriented ink on primer layer
    FI124558B (en) * 2011-08-03 2014-10-15 Upm Kymmene Corp Method and system for marking the product
    EP3164828B1 (en) * 2014-07-01 2018-08-29 Qiova Micromachining method and system for patterning a material, and method for using one such micromachining system
    TW201703879A (en) * 2015-06-02 2017-02-01 西克帕控股有限公司 Processes for producing optical effects layers

    Patent Citations (3)

    * Cited by examiner, † Cited by third party
    Publication number Priority date Publication date Assignee Title
    WO2004028825A2 (en) 2002-09-19 2004-04-08 Giesecke & Devrient Gmbh Security paper
    WO2006066431A1 (en) 2004-12-23 2006-06-29 Landqart Multilayer structure as a printing substrate, and method for the production thereof
    EP2468423A1 (en) 2010-12-27 2012-06-27 JDS Uniphase Corporation System and method for forming an image on a substrate

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