EP1878584B1 - Method for making a multi-layer body with micro-optics - Google Patents

Description

The invention relates to a method for producing a multilayer body with micro-optical structures.

To increase the security against forgery of security documents, such as banknotes or visas, numerous methods are known.

In the EP 0 429 782 A1 There is provided an arrangement for improving the counterfeit security of banknotes, which provides an OVD film applied to the banknote which is macroscopically deformed, for example by gravure printing. A macro profile is transmitted that has a maximum of 10 lines per millimeter. The macroprofile and the microprofile of the OVD are coordinated so that small deviations are immediately recognizable in counterfeit trials.

In the WO 02/091041 A1 there is described a micromirror array which is transferable to a paper or plastic substrate by printing with ink or lacquer. The period of the micromirrors is typically 30 to 60 μm. The micromirrors can be used both in transmitted and reflected light. In this way, a two-channel tilting image can be formed.

The WO-A-2004 030 928 describes a security element and a method for producing a security element in a film having a transparent or translucent layer and a reflective layer, wherein at least a part of the reflective layer is visible from a first side of the film through the transparent or translucent layer. The film is blind embossed to the layer on the reflective layer to form a transient imprinted image. The transitory image may be provided in a window or half-window formed by applying one or more opaque layers on one or both sides of the substrate in the region comprising the reflective layer and the transitory image. The document WO-A-2004 030 928 describes in particular that the transitory image can be formed from embossed lines whose embossing depth is between 5 μm and the maximum possible embossing depth of the substrate. The width-to-depth ratio is, for example, in the range of 6: 1 to 2: 1.

The DE-T-69406442 describes a safety device and method for making such safety devices. Herein, a regular two-dimensional array of substantially identical printed microimages is provided, each having a size of up to 250 μm. The microimages may be viewed by a physically separate regular two-dimensional array of substantially identical spherical microlenses having substantially the same pitch as the microimages. Each of the microlenses has a diameter in the range of 50 to 250 μm. When the micro-images are viewed through the micro-images, one or more enlarged versions of the micro-images are generated depending on the extent to which the arrangement of the micro-images and the arrangement of the microlenses are in agreement. The microimages may be mounted over an array of microimages, the allowable positional tolerance being in the range of 0.25 to 0.5 mm.

In one embodiment, a security element has a transparent plastic substrate and microimages printed on one side of the plastic substrate and viewable by microlenses disposed on the other side of the plastic substrate. This plastic substrate further has an opaque coating on both sides, wherein the coating has a window on the front side in the region of the microlenses.

The JP-A-2004 178 546 describes a provided as an optical certificate of authenticity element in which are arranged on a base material triangular prisms of a transparent material. One of the free prism sides has an unprocessed transparent surface, and the other of the free prism sides has a reflective layer or a light diffusing layer. The lower prism pages have an alphanumeric character or pattern. The triangular prisms can be created by intaglio printing. For this purpose, a radiation-curable lacquer is applied to a rotating embossing roller and a base material is pressed by means of a pressure roller on the paint, which is then dried at a drying station and cured at an irradiation station.

The JP-A-2004 347 828 describes a provided as an optical certificate of authenticity element in which are arranged on a base material triangular prisms of a transparent material. One of the free prism pages has an unprocessed transparent surface that exposes the surface of the base material.

The JP-A-2004 209 940 describes a transfer film with an intended as an optical certificate of authenticity element, in which triangular prisms are arranged on a base material. The spaces between the triangular prisms are precipitated with a transparent material, which forms transparent triangular prisms, which are covered by an adhesive layer of the transfer film.

The US-A-2004 0061325 describes a security element for a document having an intaglio-printed latent image placed over a second image that is not intaglio-printed. The latent image is formed from a highly reflective transparent ink and is visible in a first angular range near the vertical and in a second angular range closer to the surface of the document. The latent image is not visible in the angular region between the two said angular regions, but the image located below the latent image is visible. The highly reflective ink has metallic pigments, and the ink provided to form the second image has iridescent pigments. The two images are printed one after the other, with different printing methods being provided.

The US-A-2003 000 3275 describes a printed document or other element comprising a polymeric substrate. A reflective or light colored layer of ink is applied directly to the surface of the polymer substrate by a printing process. A printed image is applied to the reflective or light colored layer by an intaglio printing process. The printed image is a raised image with a height of at least 5 μm that is visible from all viewing angles. The optical effect of the image is enhanced by the reflective or light colored layer for selected viewing angles.

The invention is based on the object, a simple and inexpensive method for producing a multilayer body with micro-optical structures, which are in the registry for other security features, such as OVDs and pictorial representations.

The object of the invention is achieved by a method for producing a multilayer body having the features of claim 1.

The invention provides to apply micro-optical structures, such as microlens arrays or Blazegitter, by intaglio printing. The produced multilayer body may be both a transfer film applied to a security document or the security document itself or a security document with transfer film.

Because several micro-optical structures can be applied at the same time with this method, the effort for register-accurate alignment of the micro-optical structures is considerably reduced because it is only important to align the one or more printing plates to one another before the printing process. Thereafter, the multi-layer body can be duplicated in large quantities.

Further, it is also possible that the micro-optical structure applied in an endless, repetitive pattern on the multilayer body or in the Multi-layer body is introduced without standing in the register to other micro-optical structures.

According to the invention it is provided that both the micro-optical structures and the image areas and / or effect areas are applied in the register. The image areas may, for example, be monochrome or multicolor images, such as alphanumeric characters, logos or the like. The effect areas can, for example, be OVDs, like like a hologram, KINEGRAM ^®, blazed grating or.
The effect areas can also be tactile detectable effect areas, which, for example, make the value imprint of a bank note tangible in a suitable form. Tactile detectable areas may further provide protection against abrasion and / or contamination to other areas.

Because the micro-optical structures and / or image areas and / or the

Effect areas are applied by a printing process in the register, no additional effort for setting up or adjusting the purpose used manufacturing equipment is required. Rather, only the Intaglio printing plate must be made accurate register or more Intaglio printing plates must be adjusted to each other.

It is also possible to provide different printing inks in different areas of the Intaglio printing plate. It can be provided, for example, that two colored surfaces border on a micro-optical structure and all three elements are surrounded by a black-lined ring, wherein during printing differently colored inks and an optical paint are simultaneously transferred to the substrate to be printed. This makes it possible to easily provide the optical effects (for example colored imprints, in particular by means of effect pigments) determined by the optical properties of the lacquer in register with the microoptical structures.

The register accuracy achieved with the method according to the invention can be achieved later only with great effort, so that the proposed method has a very high security against counterfeiting. It is also not possible to procure individual components and to unify them, because individual components, such as transfer films or the like, do not physically exist. Further advantages result from the fact that the microoptical structures and / or the image areas and / or the effect areas can at least partially overlap one another, as a result of which the security against counterfeiting is further increased.

The multilayer body produced according to the invention is characterized in that micro-optical structures can be produced which are not molded into a film layer. This avoids all the problems that can arise when microoptical structures are transferred in a roll-to-roll process into a transfer film and subsequently transferred to other security features in the register for other features. Another advantage is that a micro-optical structure consisting of unconnected is formed optical elements, can not be removed and transmitted without destroying the structure. The arrangement of the micro-optical structures in the register further increases the security against forgery of the multilayer body according to the invention. The multi-layer body may have a particularly strict register, because the effort to adjust the individual matched objects arises only once.

Further advantageous embodiments are designated in the subclaims.

It can be provided that the micro-optical structures and the image areas and / or effect areas are applied by gravure printing.

It can be provided that for the formation of the micro-optical structures, an optical paint is transferred by intaglio printing on the other layers.

Alternatively, it can be provided that a layer formed from the optical lacquer is applied to the further layers and then the microoptical structures are molded into the layer formed from the optical lacquer by pressing on an intaglio printing plate which is at least partially color-free. It can therefore be provided, the gravure plate at least partially as To use stamping and press the gravure plate under high pressure on the layer formed from the optical paint, so that the optical paint completely filled in the surface of the gravure plate wells and thus the surface profile of the intaglio plate is molded into the lacquer layer. It is therefore provided in this embodiment, without printing ink. Moreover, a large number of paints are available for the process according to the invention, for example also colored optical paints and for forming the image areas and / or the effect areas the entire range of gravure printing inks.

In an advantageous embodiment, it is provided that the layer formed from the optical lacquer is transferred to the further layers by means of a transfer film. The optical lacquer can be, for example, a photopolymer lacquer whose viscosity can be adjusted by irradiation with UV light. However, the photopolymer coating must be cured after application by means of UV light.

In an advantageous embodiment, it is provided that the Intaglio printing plate is heated at least in the color-free areas.
It may be provided that the Intaglio printing plate is heated to 90 ° C to 100 ° C.
The following information is directed to the formation of the multilayer body produced by the method according to the invention. The micro-optical structures of the multilayer body are, as stated above, formed of hemispherical or pyramidal or prismatic or cylindrical optical elements with a flat base, which are transferred by intaglio pressure on the multilayer body. The said optical elements may be formed, for example, from an optical paint or the like, or from an ink or from any other printable material. However, the optical elements can also be formed by embossing by means of the pressure plate, that is to say without material transfer from the depressions of the gravure printing plate to the surface of the multilayer body.

It can be provided that the micro-optical structures have a period spacing of 100 microns to 0.3 microns, preferably have a period spacing of 20 microns to 2 microns.

Advantageously, the micro-optical structures can have a depth of 50 μm to 1 μm. It can therefore be provided that the optical elements of which the micro-optical structures are formed, have a height of 50 microns to 1 micron.

With the above ranges of the period spacing and the depth of the micro-optical structures, depth-to-width ratios and aspect ratios, respectively, can be formed in a wide range. However, very high aspect ratios can lead to mechanically unstable structures. However, such high aspect ratios are not required to form the currently known micro-optical structures.

It can further be provided that the micro-optical structure contains hidden information. The hidden information may be readable in reflected light and / or transmitted light, as explained in detail below.

It can be provided that the micro-optical structure is designed as a computer-generated hologram. It may be at the micro-optical structure may also be a grating, in particular a blazed grating, and / or a micro lens array and / or a hologram and / or a KINEGRAM ^® or the like. Although periodic structures in the range of a period length of 5 .mu.m to 0.3 .mu.m are preferred, it is also possible to use periodic structures with a period length of> 5 .mu.m, moth-eye structures, in particular in the form of sinusoidal high aspect ratio cross gratings and / or stochastic Structures act.

It may be provided that the micro-optical structure has pixels of different depth, the depth of the pixels encoding the hidden information.

It can further be provided that the hidden information in the reflected light and / or transmitted light can be read out. For example, the reading of the hidden information by means of a laser is possible by the laser beam is directed to the micro-optical structure and the light reflected from the micro-optical structure or transmitted light is detected and evaluated by means of a sensor. Further, it is possible that the laser light reflected or transmitted by the micro-optical structure is projected on a screen and evaluated by a viewer.

The micro-optical structure may have pixel-shaped partial regions with different depth, the depth of the pixel-shaped partial regions encoding the hidden information.

It can be provided that the micro-optical structure is formed as a computer-generated holographic structure having a plurality of optical elements with different heights.

It can further be provided that the pixel depth is <1.5 μm.

Preferably, 8 to 256 different pixel depths may be provided.

In an advantageous embodiment, it is provided that the pixels have a cross-sectional area of approximately 1 μm × 1 μm. It can be provided that the pixels have side lengths of 0.4 μm to 4 μm.

If the above-described micro-optical structure is arranged above a window of a carrier substrate or in a transparent area of a carrier substrate, the hidden information can be read out by transmitted light, for example with laser light. The laser beam passes through the micro-optical structure and an image of the micro-optical structure can be collected on a screen. The image may be text, such as "OK," or an image or the like, such as an eagle's drawing. As a laser light source, for example, a laser pointer can be used.

The depth of the above-mentioned pixels, from which the micro-optical structure is formed, can be determined by the following relationship: $$d\left(xy\right)=\frac{\mathrm{\Phi }\left(xy\right)•\mathit{\lambda }}{\left(\left(N-1/N\right)\right)2\mathit{\pi }\left(n_1-{\mathrm{<figure-callout\; id="0"\; label="n"\; filenames="imgf0001.png"\; state="\{\{state\}\}">n</figure-callout>}}_0\right)}$$

N denotes the number of different pixel depths, which is typically N = 64 for a so-called kinoform. When a red laser pointer having a wavelength λ = 635 nm is used, the maximum depth d needed for a phase shift angle φ = 2π and a resist layer n ₁ = 1.5 is calculated as follows: $$d\left(xy\right)=\frac{2\mathit{\pi }•635}{\left(63/64\right)2\mathit{\pi }\left(1.5-1.0\right)}=1290\mathit{nm}$$

If, in contrast, the designated micro-optical structure is applied to a non-transparent substrate, such as paper, then the laser beam is reflected by the surface of the micro-optical structure and the image can be collected, for example, on a transparent screen arranged in front of the micro-optical structure, for example on a frosted glass screen. The dimensioning equation is now: $$d\left(xy\right)=\frac{\mathrm{\Phi }\left(xy\right)•\mathit{\lambda }}{\left(\left(N-1/N\right)\right)2\mathit{\pi }•2{\mathrm{<figure-callout\; id="0"\; label="n"\; filenames="imgf0001.png"\; state="\{\{state\}\}">n</figure-callout>}}_0}$$

If a red laser pointer with a wavelength λ = 635 nm is used, the maximum depth d, which is required for a phase shift angle Φ = 2π in air with the refractive index n ₀ = 1, is calculated as follows: $$d\left(xy\right)=\frac{2\mathit{\pi }•635}{\left(63/64\right)2\mathit{\pi }•2•1.0}=323\mathit{nm}$$

The picture of the "air side" of the surface relief should be considered. The image may again be a text, such as "OK," or an image or the like, such as the drawing of an eagle.

In order to improve the visibility of the hidden image projected in reflection, a high refractive index material or a uniformly reflective material should be used for the microoptical structure.

It can be provided that the optical elements of the micro-optical structures are formed from an optical lacquer.

In an advantageous embodiment it can be provided that the optical lacquer is a high refractive optical lacquer. As already mentioned, a high refractive index can improve the reflectivity of the paint.

It can further be provided that the optical lacquer has a refractive index> 1.9.

In order to obtain a high refractive index, a photopolymer applied in the said gravure printing process may be used as the optical paint.

In an advantageous embodiment, it is provided that the optical lacquer is doped with nanoparticles. It can also be provided that the optical paint is doped with color flakes. As a result, a reflective material is obtained from the optical paint. The nanoparticles include metals in crystal form or metal salts in colloidal form, for example CdS. For example, incorporation of PbS into a polymer matrix can raise the refractive index value to 2.5 to 3.0. Nanocomposites of polymers and gold nanoparticles have already been designed with real components as low as 0.96.

Likewise, the micro-optical structure may be an OVD, such as a hologram showing the letters "AB", and may be gravure printed or embossed on the surface of the multi-layer body. The surface relief of the gravure printing plate can be produced, for example, by 2D or 3D holography or by using a dot-matrix machine. If that is the case Surface relief of the multilayer body is an undoped plastic surface relief exposed to air, the reflectivity of the OVD may be less brilliant than when HRI material or metal is used as usual, but the optical effects are present, albeit weakened. By the above-described doping of the polymer into which the surface relief is molded, the brilliance of the OVD can be increased.

It can be provided that the micro-optical structures having first layer of the multilayer body is coated with a protective layer. This protective layer can typically be applied by screen printing.
It may further be provided that it is a low-refractive protective layer.

In an advantageous embodiment it can be provided that the protective layer has a refractive index <1.5. As already stated above, the combination of a low-refractive-index protective layer with a high-index micro-optical structure or a micro-optical structure with an HRI surface can produce particularly good reflection at the micro-optical structure.

• Sicherheitsmerkmale mit verborgener Information,
  • OVDs, wie zum Beispiel Hologramme,
  • Mikrolinsenarrays für die Erzeugung von Kippbildern (Nimble Image Effect),
  • taktile Elemente,
  • Arrays von Zylinderlinsen für die Erzeugung von eindimensionalem Moiré-Effekt oder "scrambled indicia",
  • Retroreflektoren,
  • Fresnel-Linsen, beispielsweise als Lupe,
  • Flip Elemente, beispielsweise Wechsel von einer Währungsangabe zu einer Wertangabe beim Kippen des Sicherheitsdokuments,
  • Oberflächenreliefs.

As already explained above by way of example, a nontransparent security document can be formed with one or more windows. It can then be provided that the multilayer body produced by the method according to the invention is arranged at least partially over a window introduced into the security document. The security document may be, for example, a window banknote. The security document can now have the following security features, all of which are transferred from the gravure printing plate to the security document and / or the multilayer body in one production step:

• Security features with hidden information,
  • OVDs, such as holograms,
  • Microlens arrays for the generation of tilt images (Nimble Image Effect),
  • tactile elements,
  • Arrays of cylindrical lenses for the creation of one-dimensional moiré effect or "scrambled indicia",
  • Retroreflectors
  • Fresnel lenses, for example as a magnifying glass,
  • Flip elements, such as changing from a currency to a value when tipping the security document,
  • Surface relief.

In the following the invention will be clarified by way of example with reference to several embodiments with the aid of the accompanying drawings.

Fig. 1a und 1b

Verfahrensschritte eines ersten Ausführungsbeispiels des erfindungsgenäßen Verfahrens in schematischer Darstellung;

Fig. 2a und 2b

Verfahrensschritte eines zweiten Ausführungsbeispiels des erfindungsgemäßen Verfahrens in schematischer Darstellung;

Fig. 3a bis 3c

Verfahrensschritte eines dritten Ausführungsbeispiels des erfindungsgemäßen Verfahrens in schematischer Darstellung;

Fig. 4

ein erstes Anwendungsbeispiel des erfindungsgemäßen Verfahrens;

Fig. 5

ein zweites Anwendungsbeispiel des erfindungsgemäßen Verfahrens.

Show it

Fig. 1a and 1b

Method steps of a first embodiment of the erfindungsgenäßen method in a schematic representation;

Fig. 2a and 2b

Method steps of a second embodiment of the method according to the invention in a schematic representation;

Fig. 3a to 3c

Method steps of a third embodiment of the method according to the invention in a schematic representation;

Fig. 4

a first example of application of the method according to the invention;

Fig. 5

a second example of application of the method according to the invention.

Fig. 1a shows a carrier substrate 1, which is in the illustrated embodiment, a banknote, on which a multi-layer body 2 is applied, which is formed from an adhesive layer 2k and a lamination 2l and applied for example as part of the transfer layer of a hot stamping foil on the carrier substrate 1 is. The multilayer body 2 is designed as a transparent multilayer body, so that the multilayer body 2 releases the view of the carrier substrate 1 arranged below it. On the carrier substrate 1 facing away from the top of the lamination 21 is transferred by means of a gravure plate 3, an optical paint 4, which is introduced into depressions of the intaglio printing plate 3 is. The intaglio printing plate 3 is moved in the direction of the arrows 5 with a high contact pressure against a backing plate located behind the backing substrate and brought into contact with the lamination 2l, wherein the introduced into the wells of the intaglio printing plate 3 optical lacquer dissolves 4 of the wells and on the Top of the lamination 2l adheres. It forms micro-optical structures 6a and 6b in this way ( Fig. 1b ) out. The optical varnish 4 has a refractive index of about 1.5, because the micro-optical structures 6a and 6b formed by the varnish adjoin air.

The micro-optical structure 6a is a microlens array, the micro-optical structure 6b is an asymmetrical relief structure, for example a blazed grating. The microlens array may be provided to optically magnify a pictorial representation or alphanumeric characters printed on the carrier substrate. The blaze grating may be provided to form an interesting optical effect. The boundary contours of the Blaze grid can be designed, for example, as a logo or as an alphanumeric character.

The intaglio printing plate 3 may be a plate-shaped body or a cylindrical body or a curved plate arranged on a printing cylinder. It can be provided that on a printing cylinder or the like more gravure plates are arranged, for example, register in the register with the micro-optical structures 6a and 6b color layers on the lamination 2, which may form, for example, a background pattern that partially or completely through the micro-optical structures 6a and 6b is covered.

The Fig. 2a and 2b Now show a second embodiment of the method according to the invention.

Fig. 2a shows the multi-layer body 2 from Fig. 1a which is applied to the carrier substrate 1. The multilayer body 2 has the adhesive layer 2k and the laminating layer 2l. The intaglio printing plate 3 is now used only as an embossing tool, with the impression under pressure 5, the micro-optical structures 6a and 6b are molded into the laminating 2l (see Fig. 2b ). The micro-optical Structures 6a and 6b may simultaneously constitute a tactile detectable security feature.

The Fig. 3a to 3c Now show a third embodiment of the method according to the invention.

Fig. 3a shows a multilayer body 32 which is applied to the carrier substrate 1. The multi-layer body 32, like the multi-layer body 2, has the adhesive layer 2k and the lamination layer 2l, on whose side facing away from the adhesive layer an optical lacquer layer 34 is applied. Into the optical lacquer layer 34, by means of the intaglio printing plate 3 under contact pressure 5, the optical structures 6a and 6b (see Fig. 3b ) molded.

In Fig. 3c shows now in the third step, the multi-layer body 32 with an applied on the surface of the lacquer layer 34 protective layer 7. The protective layer 7 is formed with a low refractive index, for example with a refractive index <1.5, preferably with a refractive index ≈ 1. In a preferred embodiment is the protective layer 7 to a normal Abdecklack having a refractive index of about 1.5 and is applied by screen printing. In this case, the optical lacquer layer 34 advantageously has a high refractive index, for example> 1.9. It may be doped to form the high refractive index, for example with nanoparticles. The protective layer 7 increases the long-term stability of the molded in the lacquer layer 34 micro-optical structures 6a and 6b and protects them from contamination and / or wear.

Fig. 4 now shows an example of application of the method according to the invention.

A banknote 41 carries on its front side a film strip 42 having an OVD 42o and a latent image 42l. The latent image 42l is formed in this embodiment of interleaved Blazegittern, resulting in a tilted image. Another latent image 41l is executed as a color printed image and printed on the not covered by the film strip 42 surface of the banknote 41. The latent images 41l and 42l are in the in Fig. 4 illustrated embodiment arranged in alignment with each other in a spaced-apart. The latent image 42l shows the letter "O" and the latent image 41l shows the letter "K". The latent images are visible only at a predetermined viewing angle. They are invisible from all other points of view, ie latent.

In addition to the OVD 42o, another OVD 43 is applied to the surface of the banknote 41 not covered by the film strip 42.

The banknote 41 further has a microlens array 44, which is arranged above an image area 45 in the register. The OVDs 42o and 43 are also arranged in register with the microlens array 44 and are partially covered by the microlens array 44.

The arrangement in the register of the microlens array 44, the image area 45, as well as the OVDs 42o and 43 is possible by applying the method according to the invention described above under the conditions of mass production, because all designated elements applied in a gravure printing on a plant on the banknote 41 are.

Instead of the banknote, any other security document can also be provided.

The banknote 41 may optionally have a window 46, which projects at least partially into the region of the microlens array.

Fig. 5 now shows a second example of application of the method according to the invention. A window bank note 50 shown in a schematic sectional view has a carrier substrate 51 which is formed with window-like openings 51fa and 51fb. The carrier substrate 51 may be, for example, a paper suitable for banknotes or a plastic film. A laminating layer 52 includes optically variable elements (OVD) 52oa and 52ob, which may be, for example, a KINEGRAM®. The KINEGRAM® can be fully metallised, demetallised or with a through the aspect ratio of the Surface reliefs may be carried out certain metallization, run with HRI layer or as a multilayer, or designed as a system with color change effects, and there may be a (crosslinked) liquid crystal layer integrated into the system. The OVD 52ob is arranged in the window opening 51fb and can therefore be viewed both in reflected light and in transmitted light. The OVD 52oa is disposed outside the window openings 51fa and 51fb, and therefore, can only be viewed in reflected light from the front of the sill 50. The laminating layer 52 may be formed as a transparent film or as a semitransparent film, for example as a colored film.

The laminating layer 52 has on its underside an adhesive layer 53, by means of which it is connected to the carrier substrate 51. The adhesive layer may be a hot melt adhesive.

The top of the laminating layer 52 is now printed with different security elements. It is a computer-generated hologram 54g provided with hidden information; a hologram 54h which can effectively represent, for example, alphanumeric characters such as a value impression; tactile features 54t, which may provide, for example, tactile information about the value of the bill; and a microlens array 54m, which in this embodiment is registered in register with the OVD 52ob disposed in the window aperture 51fb. The microlens array 54m, when viewed from the front of the window banknote 50, produces an optically magnified image of the optical information stored in the OVD 52ob. On the other hand, when viewing the back side of the sill 50, the microlens array 54m is not optically effective, so that the optical information stored in the OVD 52ob appears to be all natural. As already described above, the holograms 54g and 54h, the tactile feature 54t and the microlens array 54m are applied in intaglio pressure in one operation and therefore arranged in a strict register relative to one another. Thus, if the microlens array 54m is deposited in register with the OVD 52ob, then the other printed elements are also in register with the OVD 52ob and any other elements incorporated in the register in the lamination layer, such as the OVD 52oa.

The computer generated hologram 54g has pixel areas of different depths. The maximum pixel depth is in the in Fig. 5 illustrated embodiment 1 micron, the pixels have a size of 1 micron x 1 micron. The hidden information is encoded in the pixel depth, which causes a change in the phase angle of the incident light. For example, 8 to 256 different depths may be provided, ie information from 8 bits to 256 bits may be stored depending on the number of different depths in a pixel.

Claims (7)

1. Method for the production of a multilayer body having a first layer formed from micro-optic structures, said layer at least partially covering one or more further layers that have image regions and/or effect regions that form an optical effect,
   characterised in that,
   the micro-optic structures (6a, 6b, 54g, 54h, 54m) are applied to the layer located beneath the first layer by means of intaglio printing or are introduced into the first layer, wherein the micro-optic structures (6a, 6b, 54g, 54h, 54m) and the image regions (45) and/or effect regions (411, 421, 42o, 43, 54t) are applied in register with the same printing plate and/or the same printing machine.
2. Method according to claim 1,
   characterised in that,
   both the micro-optic structures (6a, 6b, 54g, 54h, 54m) and the image regions (45) and/or effect regions (411, 421, 42o, 43, 54t) are applied by means of intaglio printing.
3. Method according to one of the preceding claims,
   characterised in that,
   an optical lacquer (4) is transferred to the further layers by means of intaglio printing in order to apply the micro-optic structures (6a, 6b).
4. Method according to claim 3,
   characterised in that,
   a layer (24) formed from the optical lacquer (4) is applied to the further layers and then the micro-optic structures (6a, 6b) are moulded into the layer (24) formed from the optical lacquer by means of press-fitting an intaglio printing plate.
5. Method according to claim 4,
   characterised in that,
   the layer (24) formed from the optical lacquer (4) is transferred to the further layers by means of a transfer film.
6. Method according to 4 or 5,
   characterised in that,
   the intaglio printing plate is heated, in particular that the intaglio printing plate is heated to 90°C to 100°C.
7. Method according to claim 6,
   characterised in that,
   lacquer, in particular coloured lacquer, is applied to the intaglio printing plate in a first region, and no lacquer is applied in a second region, and then the micro-optic structures are moulded in the second region by press-fitting the intaglio printing plate.

Images