Title of Invention

SECURITY ELEMENT AND METHOD FOR PRODUCING THE SAME

Abstract The invention relates to a security element for security papers, bank notes, ID cards or the like, with a substrate, on which are disposed at least two metal layers, the metal layers having different optical densities.
Full Text Security element and method for producing the same
[0001] The invention relates to a security element for security papers, bank notes,
ID cards or the like, as well as a security paper and a document of value with such a
security element. Furthermore, the invention relates to methods for producing the
security element, or the security paper and the document of value with such a security
element.
[0002] In EP 0 330 733 A1 a security thread is proposed, which can be checked
both visually as well as by machine. For this purpose a transparent plastic film is
metallically coated and this coating is provided with gaps in the form of characters or
patterns. Furthermore, the security thread contains colouring and/or luminescent
substances in the areas congruent to the gaps, by means of which under appropriate
light conditions the characters or patterns differ in a color-contrasting fashion from the
opaque metal coating. Preferably, an aluminum layer is used as metal layer. This
security thread is embedded in security papers as a so called "window security thread",
i.e. it is woven in the paper during the sheet formation of the security paper, so that in
regular intervals it is freely accessible at the surface of the paper and fully embedded
in the paper only in the intermediate areas.
[0003] This security thread already meets the requirements of a very high security
standard. The continuous metallic coating enables an automatic check of the electrical
conductivity, while the gaps serve as a visual authenticity feature, which in transmitted
light is easily recognizable by the viewer. Furthermore, the thread has an additional
feature not easily recognizable by the viewer, namely the luminescence in the area of
the gaps, which also is automatically checkable. When glancing cursory at bank notes,
which have such a security thread, however, primarily the metallic luster of the
window areas catches the eye. This luster can be imitated by simply bonding
aluminum foil elements. When checking in a cursory fashion solely in incident light,
such forgeries could be considered to be authentic bank notes.
[0004] It is therefore the problem of the present invention to propose a security
element as well as a security paper and a document of value, which, compared to prior
art, has an enhanced forgery-proofness.
[0005] This problem is solved by the features of the independent claims.
Developments are subject of the subclaims.
[0006] According to the invention the security element has a substrate, onto which
at least two metal layers with different optical densities are disposed preferably one
above the other and/or preferably on the same side of the substrate. At least the layer
with a higher optical density preferably has gaps, i.e. that at least in a partial area of
the substrate only the optically thinner layer of the at least two metal layers with
different optical densities is present. In case the metal layers are disposed one above
the other, the two metal layers adjoin each other in particular directly, i.e. no further
layers lie between the metal layers. The optical impression rendered by such a security
element can be imitated, if at all, only with great effort, in particular if different-
coloured metal layers are applied in complicated patterns with exactly defined layer
thicknesses, which possibly may also be intertwined with each other.
[0007] The metal layers have different optical densities, i.e. each layer shows a
different transmission behaviour. The optically denser metal layer of the at least two
metal layers, hereinafter referred to as metal layer A, shows a lower transmission,
preferably a maximum transmission of 30 %, especially preferred a maximum of
10 %. The optically thinner metal layer of the at least two metal layers, hereinafter
referred to as metal layer B, shows a higher transmission than layer A, preferably more
than 10 %, especially preferred 25 to 80 %. Particularly attractive effects are the result,
when the metal layer A has a maximum transmission of 10 % and the metal layer B a
minimum transmission of 50 %.
[0008] The metal layer A due to its lower transmission is perceived opaque by the
viewer, while the metal layer B shows semi transparent properties.
[0009] „Semitransparency" here means translucence, i.e. the layer shows a light
transmission ratio of under 90 %, preferably between 80 % and 20 %.
[0010] The functional correlation between transmission T and optical density OD
is formulated as follows:

[0011] The transmission values are preferably determined within the visible
spectral region, especially preferred at a wavelength of 500 nm.
[0012] Furthermore, the optical density of a metal layer depends, among other
things, on the metal used and on the layer thickness. Depending on the kind of metal
and on the transmission properties to be achieved, as a rough approximate value for
metal layer A can be assumed a layer thickness of about 20 to 300 nm and for metal
layer B a layer thickness of 2 to 20 nm.
[0013] The metal layers can be applied onto the substrate either side-by-side,
overlapping or one above the other.
[0014] In principle, the layer order of the metal layers can be any desired order.
The designations metal layer A and metal layer B do not represent the order with
respect to a carrier, but shall merely permit an easier linguistic differentiation between
a layer optically more dense and a layer optically less dense. For example, with layers
lying one above the other at first the optically denser metal layer can be applied and
then the optically thinner metal layer. However, the layer order can be vice versa as
well. Which layer order is the more suitable one results from the individual case.
[0015] In the inventive embodiment the metal layers preferably are disposed one
above the other. The metal layers disposed one above the other in particular adjoin
each other directly, i.e. no further layer is disposed between the metal layers A and B.
[0016] The metal layers A and B can consist of the same material, but also of
different materials. When combining different metals, the following color
combinations are particularly suitable: gold-/silver-coloured, gold-/copper-coloured,
chromium-/gold-coloured, chromium-/copper-coloured.
[0017] Suitable metals are, for example, aluminum, cobalt, copper, gold, iron,
chromium, nickel, silver, platinum, palladium, titanium or other „nonferrous metals
and any alloys thereof such as e.g. Inconel, gold bronzes, silver bronzes etc. For the
optically denser layer A preferably aluminum is used because of its small penetration
depth for visible light and because it is easier to process, and gold, copper, chromium,
silver or iron are used for the optically thinner layer B because of their large
penetration depth for visible light and their characteristic colour.
[0018] Some preferred material combinations are summarized in the table shown
below.
T: transmission
O: visually easily perceptible colour contrast
M: with an appropriate thickness a machine-readable magnetism in layer A is
the result
D/A: when viewed in incident light the security element appears homogeneously
metallized; in transmitted light gaps are visible.
[0019] The forgery-proofness can be additionally increased, when the gaps, i.e. the
places, where the optically denser layer is not present or which are metal-free, do not
have an only simple form, but the form of alphanumeric characters, patterns, logos or
the like, or are disposed in the form of a code, e.g. a bar code.
[0020] The optically denser metal layer when having an appropriate thickness can
additionally have magnetic properties. When the gaps are disposed in a suitable
fashion, even a machine-readable coding can be incorporated into the security element.
[0021] The substrate of the security element preferably is a plastic film. In
addition, the substrate can be provided with diffraction structures in the form of a
relief structure. The diffraction structures can be any diffractive structures, such as
holograms or grating structures (e.g. Kinegrams®, pixelgrams) or the like.
[0022] Furthermore, it is possible, that the substrate consists of films laminated
together. In particular two films can be laminated together, one metal layer at a time
being present on the outside of a film.
[0023] In the following are described the different variations of layer material and
layer structure in combination with gaps and diffraction structures and their different
forms of appearance. Of course, all variations can be combined with each other in any
desired fashion.
Variation 1: Metal layers made of the same material
[0024] In this embodiment the metal layers A and B consist of the same material.
For example, aluminum can be vapor-deposited onto the substrate as metal layer A and
B. The different optical densities of the individual layers are achieved e.g. via a
variation of the layer thickness.
[0025] The layer sequence in the security element reads, for example, substrate,
optically thin metal layer B, optically dense metal layer A. Alternatively, the layer
structure can read substrate, optically dense metal layer A, optically thin metal layer B.
Preferably, all three layers lie directly one above the other and are not separated from
each other by further layers. The optically dense metal layer A is not applied all-over,
i.e. the opaquely appearing layer A has gaps.
[0026] When viewing this security element in transmitted light, the areas not
covered with the opaquely appearing layer A are clearly recognizable as transparent
areas. Depending on how the transmission properties of the optically thin metal layer
B have been adjusted, the viewer, despite the metal coating B present in the area of the
gaps of layer A, believes to perceive fully transparent areas or semi transparent areas.
[0027] In incident light the security element appears as uniform all-over-coated
surface. I.e. the gaps are not visible.
[0028] Beside the gaps in the metal layer A, there can be gaps in the metal layer B,
too. Impressive effects are achieved, whenever the layers A and B lie one above the
other and a part of the gaps in the metal layers A and B at least partially lie one above
the other and preferably are disposed congruently, or lie one above the other and
preferably the gaps in the metal layer A are larger than the gaps in the semitransparent
metal layer B.
[0029] The gaps in one or in the two metal layers can be disposed in any form,
combination and order.
[0030] Additionally, the security element can be equipped with diffraction
structures. Preferably, these are incorporated at least into partial areas of the substrate
surface, preferably embossed, the metal layers coming to lie on the substrate surface
with the diffraction structures. Preferably, the coating order will be the following:
substrate with diffraction structure / metal layer A / metal layer B.
[0031] The diffraction structures are particularly brilliantly visible in those places,
where a metal layer is present, i.e. where is no gap. In the area of the gaps in
transmitted light the diffraction structures are only slightly visible or not visible. In
incident light the diffraction structures are visible in both the area of the metal layer as
well as the area of the gaps.
Variation 2: Metal layers made of different materials
[0032] With this embodiment the metal layers A and B consist of different
materials. For example, aluminum can be vapor-deposited onto the substrate as metal
layer A and gold as metal layer B. The different optical densities of the individual
layers are achieved e.g. via a variation of the layer thickness and/or the material.
[0033] The layer sequence within the security element and the disposition of the
gaps in the individual layers can be the same as described in variation 1.
[0034] When viewing this security element in transmitted light, the gaps in the
layer A are clearly recognizable as transparent areas. Depending on how the
transmission properties of the optically thin metal layer B have been adjusted, the
viewer, despite the metal coating B present in the area of the gaps in layer A, believes
to perceive fully transparent areas or semitransparent areas. Possibly, the
semitransparent areas stand out in colour against the surroundings due to the different
materials in layer A and B.
[0035] In incident light the security element does not appear as a uniform, all-over
coated surface, but shows another appearance in the areas not covered with the
optically denser metal, namely areas in the colour tone of the second metal. I.e. the
gaps in the metal layer A are also visible in incident light and have the colour of the
metal layer B.
[0036] Beside the gaps in the metal layer A, there can be gaps in the metal layer B,
too. Impressive effects are achieved, whenever the layers A and B lie one above the
other and a part of the gaps in the metal layers A and B at least partially lie one above
the other and preferably are disposed congruently, or lie one above the other and
preferably the gaps in the metal layer A are larger than the gaps in the semitransparent
metal layer B.
[0037] The gaps in one or in the two metal layers can be disposed in any form,
combination and order.
[0038] Additionally, the security element can be equipped with diffraction
structures. Preferably, these are incorporated at least into partial areas of the substrate
surface, preferably embossed, the metal layers coming to lie on the substrate surface
with the diffraction structures. Preferably, the coating order will be the following:
substrate with diffraction structures / metal layer A / metal layer B.
[0039] The diffraction structures are particularly brilliantly visible in those places,
where a metal layer is present, i.e. where is no gap. In incident light the diffraction
structures are recognizable also on the places of the gaps.
[0040] The following description is not restricted to the variations 1 and 2, but is to
be understood as a general description which applies to all embodiments equally.
[0041] The security element can be a security thread, which consists of a self-
supporting plastic film to which the different metal layers are applied. This security
thread can at least partially be incorporated into a security paper or security document.
If the security thread is designed such that it looks identically irrespective of whether
viewing front or back, not even the trueness to side needs to be taken into account
when incorporating the security thread. It is also thinkable to form the security element
in a ribbon-shaped or label-shaped fashion and to fasten it to the surface of the security
paper or document of value.
[0042] Alternatively, the security element can also have the form of a transfer
element or laminated film. This variation is particularly advantageous, if the security
element is disposed completely on the surface of the security paper or document of
value. In this case the layer structure of the security element is prepared on a carrier
foil, usually a plastic film, and afterwards transferred in the desired outline contours to
the security paper or document of value e.g. by means of a hot stamping method.
[0043] If the security element is disposed on the surface of the security paper or
document of value, it can have any outline structures, such as for example round, oval,
star-shaped, rectangular, trapezoidal or strip-shaped outline contours.
[0044] According to a preferred embodiment the security paper or document of
value, onto which the security element is applied, has a continuous opening. Here the
security element is disposed in the area of the opening and protrudes it on all sides.
[0045] In another preferred embodiment the security paper or document of value
has a security element in the form of a security thread.
[0046] In both embodiments the security element can be checked from both front
and back of the paper or document, which distinctly facilitates the authentication
check even for an unpractised viewer.
[0047] Therefore, an imitation of the colour effect is particularly complicated or
can be completely ruled out with these embodiments.
[0048] But the use of the inventive security element is not restricted to the area of
security documents. The inventive security element can also be advantageously used in
the field of product protection for protecting any goods from forgery. For that purpose
the security element can have additional antitheft elements, such as for example a coil
or a chip. The same applies to the security paper or document of value that is provided
with such a security element.
[0049] The application of the metal layers preferably is effected by a vapor
deposition unit, e.g. by means of sputtering or by means of an electron beam vapor
deposition method.
[0050] The manufacturing of the gaps in the respective metal layers preferably is
effected with the aid of a washing method as described in WO 99/13157, which is
incorporated herein by reference. Here the security elements are prepared in the form
of a security foil, which contains a number of simultaneous copies of the security
element. The basic material is a self-supporting, preferably transparent plastic film.
This plastic film in the case of security threads or labels corresponds to the inventive
plastic layer of the security element. When the security elements are dissolved out
from an embossed film, the plastic film forms the carrier material of this transfer
material, to which the plastic layer is applied in the form of a lacquer layer. In this
lacquer layer or, in the case of security threads or labels, in the plastic film can be
embossed diffraction structures. The inventive plastic layer of the security element is
printed in the form of the future gaps, preferably by gravure printing. For this a
printing ink with a high pigment content is used, which forms a pored, raised applied
ink layer. Afterwards the different-coloured metal layers are vapor-deposited onto the
printed plastic layer. As a last stage finally the applied ink layer and the metal layer
lying on top of it are removed by washing out with a liquid, possibly combined with
mechanical action. Preferably, a water-soluble printing ink is used, so that water can
be used as liquid. Thus this method is very environmentally friendly and does not
require any particular protective measures. Furthermore, this method has the
advantage, that the gaps in the two or several metal layers are manufactured in one
single operation.
[0051] The washing out can be supported by mechanical means, such as a rotating
roll, brush or ultrasound.
[0052] As an alternative to the vapor-deposition of the layers onto one substrate,
the layers each can be applied to a separate substrate. Afterwards, the coated substrates
are laminated together, preferably in such a way, that the coated sides of the substrates
come to lie facing each other.
[0053] Due to the fact, that the inventive security element cannot be imitated with
simple technical means and every attempt of replication is easy to detect, but also due
to the visually distinctly perceptible colour effects and incident/transmitted light
effects which are easily recognizable by a viewer, the inventive security element
shows an enormously improved forgery-proofness. In particular the security element
cannot be manufactured by the mere punching out of foil, etching away or scraping off
the metal layer, since the metallization technique and at the same time exact control of
the layer thicknesses have to be mastered.
[0054] Further embodiments and advantages of the inventive security element or
security paper and document of value are explained with reference to the figures. The
Figures are schematic diagrams and do not necessarily correspond to the dimensions
and proportions present in reality.
[0055] Fig. 1 shows an inventive document of value,
[0056] Fig. 2a shows layer structure and section through an inventive
security element along the line A - A,
[0057] Fig. 2b shows the security element according to Fig. 2a in a top view
in transmitted light,
[0058] Fig. 2c shows the security element according to Fig. 2a in a top view
in incident light,
[0059] Fig. 3a shows layer structure and section through an inventive
security element along the line A - A,
[0060] Fig. 3b shows layer structure and section through an inventive
security element along the line A - A,
[0061] Fig. 4a shows layer structure and section through an inventive
security element along the line A - A,
[0062] Fig. 4b shows the security element according to Fig. 4a in a top view
in transmitted light,
[0063] Fig. 4c shows the security element according to Fig. 4a in a top view
in incident light,
[0064] Fig. 5a shows layer structure and section through an inventive
security element along the line A - A,
[0065] Fig. 5b shows the security element according to Fig. 5a in a top view
in transmitted light,
[0066] Fig. 5c shows the security element according to Fig. 5a in a top view
in incident light,
[0067] Fig. 6a shows layer structure and section through an inventive
security element along the line A - A,
[0068] Fig. 6b shows the security element according to Fig. 6a in a top view
in transmitted light,
[0069] Fig. 6c shows the security element according to Fig. 6a in a top view
in incident light,
[0070] Fig. 7a shows layer structure and section through an inventive
security element along the line A - A,
[0071] Fig. 7b shows the security element according to Fig. 7a in a top view
in transmitted light,
[0072] Fig. 7c shows the security element according to Fig. 7a in a top view
in incident light,
[0073] Fig. 8a shows layer structure and section through an inventive
security element along the line A - A,
[0074] Fig. 8b shows the security element according to Fig. 8a in a top view
in transmitted light,
[0075] Fig. 8c shows the security element according to Fig. 8a in a top view
in incident light,
[0076] Fig. 9a to 9e show a method for producing an inventive security element,
[0077] Fig. 10a to 13 show further variations of the inventive security element in a
top view in transmitted light and in cross section.
[0078] Fig. 1 shows an inventive document of value in a top view. The shown
example is a bank note 1. This bank note has a strip-shaped security element 2, which
extends across the entire width of the bank note 1 and spans a hole 3 in the bank note.
The displayed security element is a security element that consists of a plastic layer and
two metal layers of different optical densities. At least in the optically denser layer,
optionally also in the optically thinner layer, are located the gaps. The entire surface of
the security element 2 facing the viewer is coated according to the invention, the
effects, in particular visually perceptible in the area of the hole 3, being described in
the following Figures. For clarity's sake the following Figures each show a layer
structure minimized to the basic inventive idea. Further layers, such as adhesive layers
or laminated films used for protecting the surface etc., can of course be present
additionally, and are to be added by the person skilled in the art depending on the case
of application.
[0079] Fig. 2a in a detail view shows the cross section of the security element 2
along the line A - A in Fig. 1 in a first embodiment. Here the plastic film 4 can be
recognized, which serves as a substrate for the metal layers to be vapor-deposited. In
the plastic layer the diffraction structures 5 are incorporated. Alternatively, the
diffraction structures could be incorporated in an additionally applied lacquer layer. To
the side of the plastic film, where the diffraction structures are located, a metal layer 6
is vapor-deposited directly adjoining, which is the optically denser metal layer A and
which appears opaque when viewed. In the present embodiment the metal layer A
consists of aluminum. Thereabove again a metal layer 7 is located, namely the
optically thinner metal layer B, which also consists of aluminum. In the layers 6 and 7
there are present the same diffraction structures as in plastic film 4. Additionally, in
the layer 6 are located gaps 8, which are any characters, alphanumeric characters,
patterns, logos or the like. The layer order substrate / layer A / layer B results in
advantageously designed security elements, in particular when diffraction structures
are contained in the substrate.
[0080] Fig. 2b shows how the detail of Fig. 2a appears when viewed in transmitted
light. When viewing the security element from the uncoated side of the substrate 4, in
transmitted light the gap 8 is recognizable as a transparent area or as a semitransparent
area. The gap 8, here in the form of a star, is all-over bordered by the silver appearing
aluminum layer 6.
[0081] Fig. 2c shows the same detail viewed in incident light. The gap 8 is no
longer recognizable as such and the viewer is shown a seemingly all-over
homogeneously coated security element.
[0082] In Fig. 3a a further embodiment of an inventive security element is shown
in cross section. Here the plastic film 4 at first is coated with an optically thinner
aluminum layer 7, and thereabove is located an optically denser aluminum layer 6 with
gaps 8. Onto the optically denser aluminum layer 6 a second optically thinner
aluminum layer 7 is vapor-deposited. In the area of the gap 8 the two optically thinner
aluminum layers 7 adjoin each other, the sum of the two layer thicknesses of the two
aluminum layers 7 being lower than the layer thickness of the metal layer 6. The
advantage of this embodiment is, that it is a symmetrical security element, i.e.
irrespective of whether being viewed from front or back, the appearance is always the
same.
[0083] In Fig. 3b an embodiment of an inventive security element is shown in
cross section, in which the optically denser layer 6 and the optically thinner layer 7 are
not placed one above the other, but next to each other. At first a plastic film 4 is only
partially coated with an optically thinner aluminum layer 7, e.g. in a strip-shaped
fashion. In a second stage the optically denser aluminum layer 6 is applied to the
spaces in between in exact register or slightly overlapping with layer 7. This
embodiment, too, shows the same appearance irrespective of whether viewed from
front or back. In transmitted light on the ribbon-shaped substrate the viewer sees
alternating light and dark stripes extending crosswise thereto. In incident light the
substrate appears uniformly silvery-coated.
[0084] Fig. 4a shows a further embodiment in cross section. With this variation at
first the optically thinner layer B and afterwards the optically denser layer A is applied
onto the substrate 4, in contrast to the layer order in Fig. 2a. This layer order is
preferably used for substrates not embossed. This embodiment is characterized by the
fact, that the optically thinner layer and the optically denser layer are each composed
of different metals. With respect to this no restraints are imposed upon a person skilled
in the art. By way of example one possibility, representative for many others, is
described with reference to Fig. 4a. On the substrate 4 in the left area of the Figure is
located the optically thinner metal layer 9 made of aluminum and in the right area of
the Figure is located the optically thinner metal layer 10 made of chromium. On top of
the metal layer 9 made of aluminum is located a further aluminum layer 11, though
designed as an optically denser layer. On top of the chromium coating is located the
optically denser metal layer 12 made of gold. The optically denser layers made of
aluminum and gold here are disposed in such a way, that a gap 8 is the result in the
area where the optically thinner layers 9 and 10 adjoin each other.
[0085] Fig. 4b shows the detail of the security element shown in Fig. 4a in cross
section when viewed in transmitted light. When viewing the security element from the
direction of the optically denser layer, in the left area of the image can be seen the
silvery appearing area 13 and in the right area the gold-coloured appearing area 14.
The gap 8 can be recognized as a transparent detail protruding into the area 11 as well
as into the area 12.
[0086] Fig. 4c shows the same detail in incident light. In the left area of the figure
the security element appears as all-over homogeneously silver-shining surface 13,
while in the right area of the figure 14 a silver-coloured partial area 15 is visible,
which is for the most part surrounded by the gold-coloured area 14.
[0087] Fig. 5a shows a further embodiment of the inventive security element 2. In
this variation both the optically thinner as well as the optically denser metal layer are
made of aluminum. Onto the substrate 4 at first the optically thinner aluminum layer 7
is applied, this layer already having a gap 16. Onto the optically thinner aluminum
layer 7 the optically denser aluminum layer 6 is applied in such a way, that the gaps in
the optically denser layer 8 on the one hand come to lie congruently to the gap 16 and
on the other hand are located above the optically thinner layer 7.
[0088] When viewing the security element of Fig. 5a in transmitted light, to the
viewer appears, as shown in Fig. 5b, a silver-shining ribbon with transparent areas,
which are designed on the one hand as a square 17 and on the other hand as a circle 18.
[0089] As shown in Fig. 5c, in incident light a different image is presented to the
viewer. Here the gap 16, which is congruent to gap 8, can still be perceived as
transparent area 17, while the area 18 no longer is recognizable and the security
element in this area presents itself as an apparently homogeneously coated element.
[0090] Fig. 6a shows a further embodiment of the inventive security element. In
this element, too, the optically thinner layer 7 and the optically denser layer 6 are made
of the same material, namely aluminum. The gaps in both layers are disposed in such a
way, that the gap 16 in the optically thinner layer and the gap 8 in the optically denser
layer are disposed one on top of the other, the gap 8 being larger than the gap 16. The
disposition of the layers on the substrate 4 corresponds to that shown in Fig. 5a. When
viewing this security element in transmitted light, as shown in Fig. 6b, the viewer
perceives a transparent area 19, which corresponds to the outline form of the gap 8.
Gap 16 is not recognizable as such.
[0091] When viewing this segment in incident light, as shown in Fig. 6c, only gap
16 can still be perceived as a transparent area. Again, gap 8 is perceived as a
homogeneous surface, which cannot be differentiated from the rest of the opaque
layer.
[0092] To what extent the optically thinner layer 7 is perceived as transparent or
semitransparent, depends on the respective materials and layer thicknesses. These can
be adjusted depending on the desired effect by a person skilled in the art.
[0093] Fig. 7a shows an embodiment, which shows the same layer structure as Fig.
5a, but differs from the embodiment of Fig. 5a in the fact that the optically thinner
layer 7 is made of copper and the optically denser layer 6 is made of aluminum. In
transmitted light, as shown in Fig. 7b, in the area of the gaps 8 and 16, again,
transparent areas 20, 21 are recognizable. If desired, the transmission property of the
copper layer can be adjusted in such a way, that the viewer does not perceive a fully
transparent gap in the area 21, but recognizes a slightly greenish semitransparent area.
In incident light, as shown in Fig. 7c, the gap 16 continues to be recognizable as a
transparent area 20, while in the area of the gap 8, which lies on top of the copper
layer, appears a circular-shaped, copper-coloured element 21 in silvery surroundings.
[0094] Like in Fig. 6a in Fig. 8a is shown an embodiment, in which the gap 8
comes to lie above the gap 16 and covers a larger area than the latter. In contrast to the
embodiment in Fig. 6a, Fig. 8 shows a variation wherein the optically denser layer 6
consists of aluminum and the optically thinner layer 7 of copper. The effect perceptible
in transmitted light as shown in Fig. 8b, corresponds to that shown in Fig. 6b. I.e., the
transparent surface 22, which the viewer is able to perceive, corresponds to the gap 8.
In incident light, however, Fig. 8c shows another form of appearance than the one
described in Fig. 6c. Gap 16 is recognizable as a transparent area 23 in the form of a
rectangle, while the gap 16 can be perceived as a copper-coloured triangle 22. The rest
of the surface of the security element appears silver-coloured which is due to the
aluminum layer.
[0095] Fig. 9a to 9e schematically display the method for producing an inventive
security element as shown in Fig. 5a and 7a. The method is explained by way of
example for security threads or security labels, but, of course, can be used analogously
for security elements with different layer sequences. The security elements preferably
are produced in the form of a security foil, which contains a number of simultaneous
copies of the security element. In the displayed example a self-supporting plastic film
4 forms the basis. In a first stage, as shown in Fig. 9a, this film is printed with a
strongly pigmented printing ink 24 in the areas where later the gaps 16, 8 shall be
present, so that a large-pored print is the result. Afterwards, the in this case optically
thinner metal layer 7 made of aluminum is applied to the printed plastic film 4. This is
preferably effected by a vapor deposition method, with the help of which the metals
are vapor-deposited one after the other, optionally via masks, onto the plastic film 4. In
the area of the print 24 the formation of a continuous metal layer does not take place,
which is due to the porous surface structure of the printing ink. The intermediate
product provided with the metal layer 7 is displayed in Fig. 9b.
[0096] With the first print of washable ink will be manufactured the gap 16 in the
embodiment shown in Fig. 5a and 7a. As to manufacture the gaps 8, again a print 25
with washable ink is effected on the desired place. Fig. 9c here shows the intermediate
product printed with the printing ink 24 and afterwards coated with aluminum and
again printed with ink 25.
[0097] This intermediate product then again is coated with metal, e.g. with
aluminum, so as to manufacture the optically denser layer 6 (see Fig. 9d).
[0098] Since a formation of a solid metal surface does not take place in the area of
the print 24 and 25, the print and the metal layer 6 or 6 and 7 present in this area can
be removed nearly without difficulty by washing out. Preferably, water is used for the
washing out. Possibly, it may become necessary to additionally use brushes, which
ensure a complete removal of the print 24 and 25. The final product is shown in Fig.
9e. The metal layers 6 and 7 have the gaps 8 and 16. Afterwards the security foil can
be cut into security elements of the desired form.
[0099] The washing method has the advantage that sharp and defined edges and
contours are achieved, so that with the help of this method also very fine high-
resolution characters or patterns can be manufactured in the metal layers.
[0100] Fig. 10a to 13 show further variations of the inventive security element,
gaps being combined to form positive text or negative text and maybe being present in
one or both layers.
[0101] Fig. 10a shows an embodiment, in which on the one hand the gaps 16 come
to lie in the optically thinner layer 7 congruently to the gaps 8 in the optically denser
layer 6, and on the other hand the gap 8 in the optically denser layer is substantially
larger than the gaps 16. By this explicit disposition of the gaps in transmitted light to
the viewer the writing „PL 2000" always appears as transparent area, which is
disposed in an opaque field or in a semitransparent field. In Fig. 10b the layer structure
of the security element shown in Fig. 10a can be seen in cross section. The
representation of the cross section here is restricted to the representation of the two left
fields shown in Fig. 10a.
[0102] In Fig. 1 la is shown an embodiment, in one area of which the gaps in the
optically denser and the optically thinner layer come to lie congruently and in a further
area the optically thinner layer is present all-over, while the gaps in the optically
denser layer are designed in such a way that the writing „PL 2000" stands out as
positive text against a semitransparent background. The pertinent layer structure is
displayed in Fig. 1 lb, wherein again the two left fields of the security element shown
in Fig. 1 la are displayed.
[0103] In Fig. 12a is displayed a security element, that has areas, in which the
semitransparent writing „PL 2000" appears in opaque surroundings, while in other
fields the opaque positive writing „PL 2000" appears in semitransparent surroundings.
This appearance is achieved by the fact, that the optically thinner layer 7 is present all-
over and the optically thicker layer 6 applied thereon with the desired gaps is applied
with the aim of manufacturing a positive or negative text. Fig. 12b shows the pertinent
layer structure of the two left fields shown in Fig. 12a.
[0104] In Fig. 13 various gap variations shown in the previous Figures are
combined with each other. In this security element a semitransparently appearing
negative writing „PL 2000" is present in opaque surroundings, neighboured by a
semitransparent field, in which appears the opaquely appearing positive writing
„PL 2000" which in turn is neighboured by an opaquely appearing field with the
transparently appearing writing „PL 2000". The layer structure of these three fields
corresponds to the layer structure shown in Fig. 12b combined with the layer structure
of the first field, which is shown in Fig. 11b.
Patent Claims
1. Security element for security papers, bank notes, ID cards or the like, with a
substrate, on which are disposed at least two metal layers, characterized in that
the metal layers have different optical densities.
2. Security element according to claim 1, wherein the at least two metal layers
are disposed on the same side of the substrate.
3. Security element according to claim 1 or 2, wherein the metal layers lie
directly one above the other.
4. Security element according to at least one of the claims 1 to 3, wherein the
optically thinner layer of the at least two metal layers is present at least in
those areas on the substrate, in which the optically denser layer is not present.
5. Security element according to one of the claims 1 to 4, wherein at least the
optically denser layer of the at least two metal layers has gaps.
6. Security element according to claim 5, wherein the gaps are present in the
form of alphanumeric characters, patterns, logos or the like or in the form of a
bar code.
7. Security element according to at least one of the claims 1 to 6, wherein the
optically thinner layer is present all-over.
8. Security element according to at least one of the claims 1 to 7, wherein the
optically denser layer has a maximum transmission of 30 %, preferably
maximally 10 %.
9. Security element according to at least one of the claims 1 to 8, wherein the
maximum transmission of the optically denser metal layer amounts to 10 %
and the minimum transmission of the optically thinner metal layer amounts to
50%.
10. Security element according to at least one of the claims 1 to 9, wherein the
metal layers consist of the same material.
11. Security element according to at least one of the claims 1 to 9, wherein the
metal layers consist of different materials.
12. Security element according to at least one of the claims 1 to 11, wherein the
metal can be aluminum, silver, copper, gold, iron, chromium, nickel, cobalt,
platinum, palladium, titanium, Inconel, silver bronze, gold bronze or an alloy
made of at least two of the aforementioned metals.
13. Security element according to at least one of the claims 1 to 12, wherein the at
least two metal layers have different layer thicknesses.
14. Security element according to at least one of the claims 1 to 13, wherein one
metal layer is designed opaque and one metal layer semitransparent.
15. Security element according to at least one of the claims 1 to 14, wherein a part
of the gaps in the at least two metal layers is present in a congruent fashion.
16. Security element according to at least one of the claims 1 to 15, wherein the
layer thickness of the optically denser layer amounts to between 20 and 300
nm and the layer thickness of the optically thinner layer amounts to between 2
and 20 nm.
17. Security element according to at least one of the claims 1 to 16, wherein the
substrate is a plastic layer.
18. Security element according to at least one of the claims 1 to 17, wherein the
substrate has a diffraction structure in the form of a relief structure.
19. Security element according to at least one of the claims 1 to 18, wherein the
substrate is a self-supporting plastic film.
20. Security element according to at least one of the claims 1 to 19, wherein the
substrate is disposed on a carrier material.
21. Security element according to at least one of the claims 1 to 20, wherein the
security element is a transfer element.
22. Security element according to at least one of the claims 1 to 21, wherein the
security element is a self-supporting label.
23. Security element according to at least one of the claims 1 to 22, wherein the
security element has round, oval, star-shaped, rectangular, trapezoidal or strip-
shaped outline contours.
24. Security element according to at least one of the claims 1 to 23, wherein the
security element is a security thread.
25. Security element according to at least one of the claims 1 to 23, wherein the
security element is a laminated film.
26. Security paper for producing documents of value, characterized in that it has at
least one security element according to at least one of the claims 1 to 25.
27. Security paper according to claim 26, wherein the security element is a
security thread, which is at least partially embedded in the security paper.
28. Security paper according to claim 26, wherein the security paper has a
continuous opening and the security element is disposed in the area of the
opening and protrudes it on all sides.
29. Security paper according to claim 26, wherein the security element is a
transfer element or a laminated film, which is applied onto the surface of the
security paper.
30. Security paper according to at least one of the claims 26 to 29, wherein the
security element has round, oval, star-shaped, rectangular, trapezoidal or strip-
shaped outline contours.
31. Document of value, such as a bank note, ID card or the like, characterized in
that it has at least one security element according to at least one of the claims 1
to 25.
32. Transfer material or laminated film for producing security elements, which has
a carrier foil and a substrate, on which at least two metal layers are disposed,
characterized in that the metal layers have different optical densities.
33. Transfer material or laminated film according to claim 32, wherein the at least
two metal layers are disposed on the same side of the substrate.
34. Transfer material or laminated film according to claim 32 or 33, wherein the
metal layers lie directly one above the other.
35. Transfer material or laminated film according to at least one of the claims 32
to 34, wherein the optically thinner layer of the at least two metal layers is
present at least in those areas on the substrate, in which the optically denser
layer is not present.
36. Transfer material or laminated film according to at least one of the claims 32
to 35, wherein at least the optically denser layer of the at least two metal layers
has gaps.
37. Transfer material or laminated film according to at least one of the claims 32
to 36, wherein the substrate is a plastic layer.
38. Transfer material or laminated film according to at least one of the claims 32
to 37, characterized in that the substrate has a diffraction structure in the form
of a relief structure.
39. Use of a security element according to at least one of the claims 1 to 25 for
protecting goods of any kind from forgery.
40. Use of a security paper according to at least one of the claims 26 to 30 for
protecting goods of any kind from forgery.
41. Use of a document of value according to claim 31 for protecting goods of any
kind from forgery.
42. Method for producing a security element for security papers, bank notes, ID
cards or the like, with a substrate, on which are disposed at least two metal
layers, the metal layers having different optical densities, characterized by the
following stages:
a1) providing the substrate in the form of a self-supporting plastic film or in
the form of a carrier material on which is disposed a plastic layer;
b1) optionally, printing the substrate with alphanumeric characters, patterns,
logos or the like using a printing ink with a high pigment content and
drying the printing ink as to form a pored, raised applied ink layer;
c1) applying the optically thinner metal layer onto the, optionally, printed
substrate;
d1) printing the optically thinner metal layer with alphanumeric characters,
patterns, logos or the like using a printing ink with a high pigment
content and drying the printing ink as to form a pored, raised applied ink
layer;
e1) applying the optically denser metal layer onto the optically thinner metal
layer;
f1) removing the applied ink layer and the metal layer or metal layers lying
thereabove or having penetrated the applied ink layer, by washing out
with a liquid, possibly combined with mechanical action;
g1) drying and, optionally, cutting the substrate to size.
or
a2) providing the substrate in the form of a self-supporting plastic film or in
the form of a carrier material on which is disposed a plastic layer;
b2) printing the substrate with alphanumeric characters, patterns, logos or the
like using a printing ink with a high pigment content and drying the
printing ink as to form a pored, raised applied ink layer;
c2) applying the optically denser metal layer onto the printed substrate;
d2) removing the applied ink layer and the metal layer or metal layers lying
thereabove or having penetrated the applied ink layer, by washing out
with a liquid, possibly combined with mechanical action;
e2) applying the optically thinner metal layer onto the optically denser metal
layer;
f2) optionally, cutting the substrate to size.
43. Method according to claim 42, wherein the metal layers are applied by vapor
deposition, optionally with the aid of masks.
44. Method according to claim 42 or 43, wherein the substrate is provided in the
form of an endless ribbon and the method is performed continuously.
45. Method according to at least one of the claims 42 to 44, wherein the printing
ink is water-soluble and water is used for washing out.
46. Method according to at least one of the claims 42 to 45, wherein the printing
of the substrate is effected by gravure printing.
47. Method according to at least one of the claims 42 to 46, wherein in stage al)
or a2) the plastic layer is provided in the form of an endless plastic film and in
stage g1) or f2) is cut into security threads of predetermined width.
48. Method according to at least one of the claims 42 to 47, wherein in stage al)
or a2) the plastic layer is disposed on a specifically prepared carrier material,
so as to form a transfer material that is cut into stripes of predetermined width
in stage g1) orf2).
49. Method according to at least one of the claims 42 to 48, wherein a diffraction
structure is embossed into the substrate before stage b1) or b2).
50. Method for producing a security paper for the production of documents of
value, characterized in that during the production of the security paper a
security thread produced according to at least one of the claims 42 to 49 is
embedded.
51. Method for producing a security paper for documents of value, characterized
in that onto the surface of the finished security paper is applied a security
element, which has been produced according to at least one of the claims 42 to
49.
52. Method according to claim 51, characterized in that during the papermaking
an opening is incorporated into the security paper, which afterwards is closed
at least on one side with the security element.

The invention relates to a security element for security papers, bank notes, ID cards or
the like, with a substrate, on which are disposed at least two metal layers, the metal
layers having different optical densities.

Documents:

1475-KOLNP-2004-ABSTRACT 1.2.pdf

1475-KOLNP-2004-ABSTRACT-1.1.pdf

1475-kolnp-2004-abstract.pdf

1475-KOLNP-2004-AMENDED CLAIMS.pdf

1475-KOLNP-2004-AMNDED PAGES OF SPECIFICATION.pdf

1475-kolnp-2004-assignment-1.1.pdf

1475-kolnp-2004-assignment.pdf

1475-KOLNP-2004-CLAIMS 1.1.pdf

1475-kolnp-2004-claims.pdf

1475-KOLNP-2004-CORRESPONDENCE 1.2.pdf

1475-KOLNP-2004-CORRESPONDENCE-1.1.pdf

1475-kolnp-2004-correspondence-1.3.pdf

1475-kolnp-2004-correspondence.pdf

1475-KOLNP-2004-DESCRIPTION (COMPLETE) 1..pdf

1475-KOLNP-2004-DESCRIPTION (COMPLETE)-1.1.pdf

1475-kolnp-2004-description (complete).pdf

1475-KOLNP-2004-DRAWINGS 1.2.pdf

1475-KOLNP-2004-DRAWINGS-1.1.pdf

1475-kolnp-2004-drawings.pdf

1475-KOLNP-2004-EXAMINATION REPORT REPLY RECIEVED 1.1.pdf

1475-kolnp-2004-examination report.pdf

1475-KOLNP-2004-FORM 1 1.2.pdf

1475-KOLNP-2004-FORM 1-1.1.pdf

1475-kolnp-2004-form 1.pdf

1475-kolnp-2004-form 18-1.1.pdf

1475-kolnp-2004-form 18.pdf

1475-KOLNP-2004-FORM 2 1.2.pdf

1475-KOLNP-2004-FORM 2.pdf

1475-KOLNP-2004-FORM 3-1.1.pdf

1475-kolnp-2004-form 3.pdf

1475-kolnp-2004-form 5-1.1.pdf

1475-kolnp-2004-form 5.pdf

1475-KOLNP-2004-FORM-27.pdf

1475-kolnp-2004-gpa-1.1.pdf

1475-kolnp-2004-gpa.pdf

1475-kolnp-2004-granted-abstract.pdf

1475-kolnp-2004-granted-claims.pdf

1475-kolnp-2004-granted-description (complete).pdf

1475-kolnp-2004-granted-drawings.pdf

1475-kolnp-2004-granted-form 1.pdf

1475-kolnp-2004-granted-form 2.pdf

1475-kolnp-2004-granted-specification.pdf

1475-kolnp-2004-intenational publication.pdf

1475-kolnp-2004-others 1.1.pdf

1475-kolnp-2004-others-1.2.pdf

1475-KOLNP-2004-OTHERS.pdf

1475-KOLNP-2004-PETITION UNDER RULE 137.pdf

1475-kolnp-2004-reply to examination report-1.2.pdf

1475-KOLNP-2004-REPLY TO EXAMINATION REPORT.pdf

1475-kolnp-2004-specification.pdf

1475-kolnp-2004-translated copy of priority document.pdf


Patent Number 246907
Indian Patent Application Number 1475/KOLNP/2004
PG Journal Number 12/2011
Publication Date 25-Mar-2011
Grant Date 21-Mar-2011
Date of Filing 05-Oct-2004
Name of Patentee GIESECKE & DEVRIENT GMBH
Applicant Address PRINZREGENTENSTRASSE 159, 81677 MUNCHEN
Inventors:
# Inventor's Name Inventor's Address
1 HEIM MANFRED ALFREDSCHMIDT-STRASSE 35, 81379 MUNCHEN
2 SCHMITZ CHRISTIAN JOSEFSTALERSTRASSE 3G, 83727 SCHLIERSEE-NEUHAUS
PCT International Classification Number B42D
PCT International Application Number PCT/EP2003/04221
PCT International Filing date 2003-04-23
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 102 18 897.1 2002-04-26 Germany