|Title of Invention||
SECURITY ELEMENT FOR OBJECTS OBJECT COMPRISING SUCH A SECURITY ELEMENT AND METHOD FOR PRODUCING SAID SECURITY ELEMENT AND SAID OBJECT
|Abstract||Security element for objects, in particular for documents of value such as bank notes and credit cards, comprising several layers (I, R, M) located on top of each other, namely at least one a color shift effect producing interference element (I) and a layer (M) with magnetic properties, characterized in that a reflection layer (R) is disposed between the layer (M) with magnetic properties and the at least one interference element (I), wherein the layer (M) with magnetic properties and the reflection layer have gaps (10, 20) in the form of symbols or patterns or codings.|
|Full Text||SECURITY ELEMENT FOR OBJECTS. OBJECT COMPRISING SUCH A
SECURITY ELEMENT AND METHOD FOR PRODUCING SAID SECURITY
ELEMENT AND SAID OBJECT
 This invention relates to a security element for objects in general and for
documents of value in particular, as for example bank notes, credit cards and the like.
Furthermore, the invention relates to objects equipped with such a security element as
well as to methods for producing such security elements and objects. Such objects can
also be semifinished products for further processing, for example unprinted bank note
 In order to prove the authenticity of objects and to be able to differentiate
objects from forgeries, these are provided with complex, forgery-proof, visually and/or
automatically testable security elements. Objects particularly worthy of protection are
documents of value, in particular bank notes, checks, check cards, credit cards, identity
cards, passports, admission tickets, tickets for public transport and the like.
 The more complex the security elements and the more elaborate the
production of them, the higher the forgery protection. One security element often
combines several different security features which are partly hidden and therefore only
machine-readable or discernible with the help of additional apparatus and which are
partly visible to the naked eye so as to enable a visual test. The combination of several
security features in one security element is not always easily to realize and from time to
time involves compromises, which cause particular security features to no longer be able
to develop their optimal effect.
 For example, from WO 01/03945 Al a multilayer security element for
security documents, bank notes and credit cards is known, which combines a layer with
embossed diffraction structures with a color shift layer. Here color shift effect means the
effect of color change from different viewing angles. Each of both security features
offers effective copy protection and has optical effects easily to visually test.
Additionally, both security' features caa only be imitated with great efforts. The optical
effect of embossed holograms is substantially enhanced when the diffraction structures
are viewed in front of a reflecting background, and the color shift effects, too, are
brought out especially intensively in front of a specularly reflective background.
Therefore, in WO 01/03945 Al is, among other things, proposed to combine the layer
provided with diffraction structures and the color shift effect layer with a common
reflective metal background layer. This reflective metal background layer can
additionally have magnetic properties so that a further third magnetic security feature is
integrated in the security element.
 The problem with a reflective background coating with magnetic properties is
the fact that magnetic materials as a rule have poor reflection properties. Those with
acceptable reflection properties, however, have less distinct magnetic properties. In EP 0
341 002 Bl a thin-layer structure with a color shift effect layer and a magnetic metal
background coating of a cobalt nickel alloy is proposed as security element. Such a
background coating should have acceptable reflection properties as well as good
magnetic properties. Nonetheless, the reflection properties are not optimally.
 It is therefore the problem of the present invention to propose an improved
multilayer security element with optimized, i.e. intensive color shift effect and with at
the same time optimized magnetic properties, an object provided with such a security
element and methods for producing the security element and the object.
 This problem is solved according to the invention by a security element for
objects, in particular for documents of value such as bank notes and credit cards,
comprising several layers located on top of each other, namely at least one a color shift
effect producing interference elemenl and a layer with magnetic properties, characterized
in that a reflection layer is disposed between the layer with magnetic properties and the
at least one interference element, wherein the layer with magnetic properties and the
reflection layer have gaps in the form of symbols or patterns or codings.
The invention also provides an object comprising such a security element.
Further, the invention provides a method for producing the security element,
comprising the steps: providing a substrate, coating the substrate with at least one
interference element, with a layer with magnetic properties and with a reflection layer in
such a way, that the reflecting metal layer is located between the layer with magnetic
properties and the at least one interference element, wherein by partial removal of the
reflecting metal layer and the layer with magnetic properties transparent areas in the
form of symbols, patterns or codings are produced.
Advantageous embodiments and developments of the invention are described
 According to this the multilayer security element has an interferential layer
structure, which produces a color shift effect when the security element is viewed from
different angles, and a layer with magnetic properties. The interferential layer structure
here is composed of a multilayer inlerference element I and a reflection layer R. The
interference element, the reflection layer and the layer with magnetic properties here are
disposed in such a way, that the reflection layer is located between the interference
element and the layer with the magnetic properties. The reflection layer usually is a
reflecting metal layer.
 The interference element is formed by absorber and dielectric layers located
one on top of the other, wherein also several absorber and dielectric layers can be dis-
posed in turns on top of each other. Instead of alternating absorber and dielectric lay-
ers, exclusively dielectric layers can be provided, too, adjoining layers having strongly
different indices of refraction so as to produce a color shift effect. The use of absorber
layers, however, is advantageous, because the color shift effect is visible better.
 Optical interference coatings with color shift effect are widely known and in
connection with security elements described in, for example, EP 0 395 410 Bl,
EP 0 341 002 Bl, WO 01/03945 Al and US 3,858,977. Their special property is that
they render different color impressions from different viewing angles. According to
kind and number of layers in the layer structure,, two, three, four or more color effects
depending on the viewing angle can occur. Reflection and transmission properties of
such color shift effect layers depend on several factors, in particular on indices of re-
fraction, absorption coefficients and layer thicknesses as well as on the number of lay-
ers in the layer structure.
 According to the invention, the individual layers of the optical interference
element as well as the reflective metaTrayeTarid the layer with magnetic properties are
ap^ITe^rprei&ably vapor-deposited, to a substrate, the layers overlapping each other at
least partially. Here it is essential that the reflecting metal layer is disposed between
the layer with magnetic properties and the interference element, so as to the reflection
layer can take its positive optical effect as background for the interference element.
 The multilayer security element can be put on an object with or without the
substrate, for example by the hot stamping method. In case of a transfer without the
substrate the multilayer security element is produced on one side of the substrate, the
layer order here can be either substrate / interference element / reflection layer / mag-
netic layer or substrate / magnetic layer / reflection layer / interference element. In
case the security element is applied together with the substrate to an object or inte-
grated in an object, for example as a label on or as a window thread in a bank note,
then the magnetic layer can also be present on the back of the substrate.
 The security element structured according to the invention can be combined
with further security features, in particular with a negative or positive writing by local
removal of reflection layer and magnetic layer. The writing preferably represents al- „
phanumeric characters but is not restricted to that. Within the terms of the invention
this can be every symbol, pattern or coding that can be represented. Alternatively or
additionally, diffraction structures can be present on or in the substrate the layers are
produced on, or on or in a separate layer, for example an embossed lacquer layer.
 By local removal of the magnetic layer and the reflection layer the security
element becomes, dependent on the design of the individual layers, partially transpar-
ent or semitransparent, since the interference element is transparent or semitransparent.
„Semitransparency" here means translucence, i.e. a translucent security element shows
a light transmission ratio of under 90 %, preferably between 80 % and 20 %. When
using such a partially semitransparent security element, for example as a security
thread in a bank note, an incident light/transmitted light effect is the result. That means
the symbols, patterns and codings of the security thread embedded in the bank note are
not perceptible in incident light, but when viewed in transmitted light they become
clearly apparent as brighter areas vis-a-vis a darker surrounding.
 The inventive security element is especially suitable for the combination with
diffraction structures for producing further color effects. The diffraction structures are,
for example, grating structures, refraction patterns, reflection, transmission, or volume
holograms. Diffraction structures can be present, for example directly as embossings
in the substrate bearing the layers, for example in the carrier material of a plastic
thread, or else be placed in an additional layer. The additional layer can be, for exam-
ple, a lacquer layer. The color effects obtained therewith are based on a diffraction of
the light in the embossed relief structures. Such diffraction structures develop the most
intensive optical effect in front of a reflecting metallic background. The inventive se-
curity element already has a reflecting metallic layer, which therefore can easily serve
as a reflecting metallic background for the diffraction structure.
 The metallic reflection layer can consist of, for example, aluminum, silver,
nickel, platinum or palladium, preferably of aluminum or silver. Both materials are
electrically conductive, so that the electrical conductivity of the security element can
be taken into consideration as an additional security feature.
 In the following, by way of example only, the invention is described with refer-
ence to the accompanying figures. The proportions shown in the figures do not neces-
sarily correspond to the dimensions present in reality and primarily serve for the im-
provement of clarity.
 Figure 1 schematically shows the layer order of an inventive security ele-
 Figures 2-6 show the layer structure of an inventive security element in com-
bination with a substrate with embossed diffraction structures
which is disposed at different places within the layer structure;
 Figure 7 shows the layer structure of a security element according to figure
4 with gaps in the magnetic layer and the reflection layer;
 Figure 8 shows a semifinished product with several connected security
elements in top view with a layer structure according to figure 7;
 Figure 9 shows the cross-section of a security thread which is embedded as
a window thread in a bank note.
 The technical explanations for the individual figures are not restricted to the
embodiment shown in the respective figures, but also serve as explanations for the
general inventive idea.
 Figure 1 partially shows the cross-section of the layer structure of a security
element 1 according to a basic embodiment of the present invention. The layer struc-
ture with color shift effect comprises a multilayer interference element I, a layer M
with magnetic properties and a reflection layer R located between the interference
element I and the layer M with magnetic properties. Such a security element 1 is put
on an object or integrated in an object in such a way, that the interference element I is
visually perceptible, i.e. it is facing the observer.
 This applies to all embodiments also to those of Fig. 2 to 7. Any transparent or
semitransparent layers may well be additionally provided on top of the interference
element I or as intermediate layers.
 The interference element I also has a multilayer structure and comprises of at
least two layers, namely in the embodiment according to figure 1 an absorber layer A
and a dielectric layer D therebelow. The physical effects, in principle known by ex-
perts, of the individual layers within the interference layer structure, consisting of re-
flection layers and interference elements, when producing the color shift effect are de-
scribed, for example, in EP 0 395 410 Bl. As absorber layer A typically serves a metal
layer of materials such as chromium, iron, gold or titanum of a thickness of preferably
4 ran to 20 nm. Compounds such as nickel chromium iron, but also metals such as va-
nadium, palladium or molybdenum can be used as materials for absorber layers, too.
Further suitable materials for the absorber layer are specified, for example, in
WO 01/03945 Al, e.g. nickel, cobalt, tungsten, niobium, aluminum, metal compounds
such as metallic fluorides, oxides, -sulphides, -nitrides, -carbides, -phosphides, -
selenides, -silicides and compounds thereof, but also carbon, germanium, cermet, iron
oxide and the like.
 For the dielectric layer mainly transparent materials with a low index of refrac-
tion n (n A1203. In principle, nearly all clear compounds which can be vapor-deposited are ac-
ceptable, therefore, in particular also higher refracting coating materials such as Zr02,
ZnS, Ti02 and indium tin oxides (ITO). Further suitable dielectric layers are specified,
for example, in WO 01/03945 Al.
 The layer thickness of the dielectric layer D usually is in a range of 100 nm to
1000 nm, preferably 200 nm to 500 nm.
 Instead of absorber layers A also dielectric layers D can be used, wherein the
refractive indices of adjoining dielectric layers D have to be greatly different, i.e. on
the one hand n 1.7 so as to cause a distinct color shift
 The reflection layer R preferably is a metal layer of silver or aluminum or of
another strongly reflecting metal. The reflection layer R is of decisive significance for
the desired color shift effect. The better the reflection properties in the reflection layer
R, the more striking is the color shift effect.
 The layer M with magnetic properties is preferably a magnetic metal layer con-
sisting of nickel, iron, cobalt or an alloy consisting of the said metals or an alloy con-
sisting of one of the said metals and other materials, wherein at least one of the said
three materials has a weight share of at least 20%. As to the magnetic properties in the
magnetic layer M are sufficiently pronounced for an automatic test, the thickness of
the magnetic layer M preferably is between 10 nm and 1000 nm. The material of the
magnetic layer M can bechosen in such a way that it has the desired magnetic proper-
ties. In particular coercive force and remanence properties can be adjusted optimally,
since the magnetic layer M has no reflection function for the interference element I at
all. The magnetic layer M can also be present, for example, as coding, like a bar code,
without impairing the optical properties of the security element. Since the magnetic
layer M is located, invisible for the observer, behind the reflection layer R. Thus the
optical properties and magnetic properties of the security element are completely de-
coupled from each other by the presence of the reflection layer R.
 All layers A, D, R, M are preferably produced by means of a vacuum vapor
deposition method on a substrate which can form a component of the security element
1, but which can also serve only as an intermediate carrier and is removed when the
security element is applied to or in an object at the latest. Most different vapor deposi-
tion methods are suitable for the production of the layers, one methodic group is
formed by physical vapor deposition (PVD) with evaporation boat, vapor deposition
by resistance heating and vapor deposition by induction heating. But also electron-
beam vapor deposition, sputtering (DC or AC) and electric-arc vapor deposition are
possible. Furthermore, the vapor deposition can also be effected by chemical vapor
deposition (CVD) or by sputtering in reactive plasma or any other plasma activated
vapor deposition method. Apart from vapor deposition methods layers can, if possible,
also be printed on. Here the magnetic layer can be placed in the layer structure with
the use of suitable printing inks.
 In figures 2 to 6 different possible layer structures of an inventive security ele-
ment are shown, the substrate S being disposed at different places in the layer order I-
R-M. According to that the substrate S can be located below or on top of the layers I,
R, M (figures 2, 3, 5). It can, however, also be located between the reflection layer R
and the magnetic layer M (figure 5). If the substrate is located on top of the interfer-
ence element I (figure 4, 6), it is important that the substrate S is as much as possible
transparent or at least semitransparent, as to not negatively influence the intensity of
the color shift effect.
 In the security element according to the invention diffraction structures can be
integrated particularly well, preferably in the substrate S, but they can also be formed,
if desired, by a separate layer. Here the diffraction structures can extend all over the
whole security element or are only present in partial areas.
 In figures 2, 4, 5 and 6 diffraction structures 2 are embossed in a carrier foil or
in the substrate S. The metallic coating for intensifying the visual impression of the
diffraction image typically present in this connection, is already embodied in the in-
ventive security element by the reflection layer R and therefore needs not to be pro-
vided separately. An optimal visual impression of a reflection hologram is obtained,
when the reflection layer R immediately adjoins the diffraction structure 2 as to be
seen in figure 5. With an embossed diffraction structure the embossing process pref-
erably is effected before the coating of the substrate S. However, in case the magnetic
layer M is located between the reflection layer R and the embossed substrate S, as
shown in figure 2, the optical quality decreases with the increasing thickness of the
magnetic layer M. In this case it may be advantageous to emboss the diffraction struc-
tures in the metal-coated substrate surface.
 The embossed relief structure can also be at a distance from the reflection layer
R, provided that in any case the reflection layer R forms the background to the em-
bossed relief structure 2 for the observer, as to be seen in figures 4 and 6. The optical
impression of a reflection diffraction structure with a reflection layer at a distance,
however, is less brilliant.
 Instead of the diffraction structures being integrated in the substrate, they can
also be present in a separate layer. Fig. 3 shows a layer structure comparable to that in
Fig. 2, wherein between the substrate and the magnetic layer a separate layer, here a
lacquer layer L, is present, in which diffraction structures 2 are embossed. The em-
bossed lacquer layer alternatively coulci be located between the layers M and R or on
top of layer A.
 In principle diffraction structures can be placed between all layers or on top of
the outer surfaces of the outer layers, as long as the layer unit consisting of interfer-
ence element I and reflection layer R is not interrupted. The diffraction structures here
reproduce themselves in the subsequently applied layers.
 The reflecting metal layer R present in the security element, according to a pre-
ferred embodiment: of the invention is interrupted so as to produce a writing, pattern or
code visible in transmitted light, the magnetic layer having to be interrupted in the
same area as to not impede the transmitted light effect. For the production of such a
security element, transparent or at leasl semitransparent plastic films are vapor-
deposited all over with a magnetic layer M and a reflection layer R. In these layers are
placed gaps in the form of the desired characters, patterns and codings with the help of
known methods (washing method, etching, spark erosion etc.). Preferably the washing
method is used, during which at first trie desired pattern is printed on the carrier mate-
rial with washable ink. Then the vapor deposition of the reflection layer and magnetic
layer is effected. By means of washing, the layers above the washable ink are re-
moved, too, so that at this place a gap is produced. A number of methods for produc-
ing symbols and patterns are known to experts. In particular, the reflection layer R and
the magnetic layer M can be applied separately and etched or washed separately, if, for
example, the gaps in the magnetic layer M are to have a size differing from that of the
symbols, patterns and codings in the reflection layer R.
 By way of example only, this is shown in figures 7 and 8 in a security element
with a layer structure according to figure 4. On the substrate S in the form of a plastic
film with embossed diffraction structure 2 the interference element I is vapor-
deposited and adjoining the interference element I at first the reflection layer R and
then the magnetic layer M. The reflection layer R has gaps 20 in the form of a repeated
writing „PL", as to be seen in figure 8. The gaps 10 in the magnetic layer M are sub-
stantially larger than the gaps 20 in the reflection layer R and form a magnetic bar
code 11, as also to be seen in Fig. 8. The code can be seen, depending on the embodi-
ment, in the positive or negative patterns, i.e. in the magnetic areas or in the gaps.
 Figure 8 shows an intermediate product 100 from top view for producing nu-
merous security elements 1 in the form of security threads 200 with the cross-section
shown in figure 7. The gaps 20 in the form of the characters „PL" are visible through
the interference element I and the transparent carrier material or substrate S. The mag-
netic layer M located behind the reflection layer R, and therefore not visible in plan
view, is only present in partial areas 11 which form a bar code and are faintly marked
in dot-and-dash pattern in figure 8.
 The intermediate product 100 shown in figure 8, in a subsequent procedure
step, is separated along the separating line 101 so as to form security threads 200 for
the embedding in e.g. bank notes. The characters „PL" formed by the gaps 20 in the
reflection layer R are hardly discernible in incident light in a security thread embedded
in a bank note, in transmitted light, however, they are perceptible as negative writing.
 Security threads with a structure; as described in figures 7 and 8 are particularly
suitable for the use as window security thread, which is embedded in a document in
such a way, that it is at least in places directly visible or emerging at the surface. This
is shown in figure 9 with the cross-section of a bank note 300 as example. Methods for
embedding the security thread 200 in paper under the forming of windows in the area
of the security thread are described e.g. in DE-A-36 01 114. With a thread embedded
in such a way, when viewed in incident light, in the window area mainly the diffrac-
tion structure or reflection pattern is visible, however, when viewed in transmitted
light the negative writing present in the metal coating dominates. In both cases the
color shift effect caused by the interference layer structure remains perceptible.
 The inventive security element thus combines in its simplest embodiment three
security features in an optimal way with each other, namely on the one hand a color
shift effect in combination with an optimal reflecting metal layer, whose electrical
conductivity forms a second security feature, and finally a magnetic security feature,
whose properties can be optimally adjusted without negatively affecting the other se-
 Further security features can be combined with the inventive security element,
for example, by means of a partial removal of the reflection layer as to form patterns
or symbols and/or partial removal of the magnetic layer as to form a coding, for exam-
ple a bar code, as well as by combination with diffraction structures, in particular in
the form of an embossed structure, preferably adjoining the already present reflection
 One preferred area of use of the inventive security element has already been
stated above as security thread, in particular as machine-readable magnetic-hologram
window security thread with color shift effect and negative writing. However, the se-
curity element can also be bonded as stripe or plane element to an object, in particular
a document of value, preferably a bank note, or in another way with or without the
substrate be transferred to an object, for example by hot stamping method.
We Claim :
1. Security element (1, .200) for objects, in particular for documents of value
(200) such as bank notes and credit cards, comprising several layers (I, R,
M) located on top of each other, namely at least one a color shift effect
producing interference element (I) and a layer (M) with magnetic
properties, characterized in that a reflection layer (R) is disposed between
the layer (M) with magnetic properties and the at least one interference
element (I), wherein the layer (M) with magnetic properties and the
reflection layer have gaps (10, 20) in the form of symbols or patterns or
2. Security element as claimed in claim 1, wherein the gaps (10) in the layer
(M) with magnetic properties are larger than the gaps (20) in the reflection
layer (R) and form a machine-readable coding (11).
3. Security element as claimed in at least one of the claims 1 and 2,
comprising diffraction structures.
4. Security element as claimed in at least one of the claims 1 to 3,
comprising a substrate (S), on which the layers (I, R, M) are present.
5. Security element as claimed in claim 4, wherein the substrate (S) is
provided with diffraction structures (2).
6. Security element as claimed in claim 5, wherein the diffraction structures
(2) are embossed in a surface of the substrate (5).
7. Security element as claimed in claim 3, wherein the diffraction structures
(2) are integrated in an addilional layer.
8. Security element as claimed in at least one of the claims 3 to 7, wherein
the reflection layer (R) adjoins the diffraction structures (2).
9. Security element as claimed in at least one of the claims 3 to 7, wherein
the interference element (I) comprises an absorber layer (A) and which
adjoins the diffraction structures.
10. Security element as claimed in at least one of the claims 1 to 9, wherein
the security element is formed as a security thread (200).
11. Security element as claimed in at least one of the claims 1 to 9, wherein
the security element is formed as a plane element or stripe for application
to objects, in particular documents of value.
12. Security element as claimed in claim 11, wherein the security element is
formed as a transfer element.
13. Object comprising a security element (1) as claimed in at least one of the
claims 1 to 12.
14. Object as claimed in claim 13, wherein the object is a document of value
15. Object as claimed in claim 14, wherein the security element is a security
16. Object as claimed in claim 15, wherein the security thread (200) in the
document of value (300) is embedded as a window thread.
17. Object as claimed in at least one of the claims 13 and 14, wherein the
security element (1) is put on the object.
18. Object as claimed in at least one of the claims 13 to 17, wherein the object
is a bank note (300).
19. Method for producing a security element as claimed in at least one of the
claims 1 to 12, comprising the steps:
providing a substrate (S).
coating the substrate S with at least one interference element (I),
with a layer (M) with magnetic properties and with a reflection layer
(R) in such a way, that the reflecting metal layer (R) is located
between the layer (M) with magnetic properties and the at least one
interference element (1), wherein by partial removal of the reflecting
metal layer (R) and the layer (M) with magnetic properties
transparent areas (20) in the form of symbols, patterns or codings are
20. Method as claimed in claim 19, wherein a diffraction structure (2) is
placed, in particular embossed, in or on top of the substrate (S) or an
21. Method as claimed in claim 19 or 20, wherein the layers are produced
with a vapor deposition method.
22. Method as claimed in at least one of the claims 19 to 21, wherein the
layers (I, R, M) are applied to one side of the substrate (S).
23. Method as claimed in claim 19, wherein from the layer (M) with magnetic
properties are removed larger parts than from the metal layer (R), so that
the layer (M) with magnetic properties forms a machine-readable coding
(11) which is different from the semitransparent areas (20).
24. Method for producing an object with a security element (1) as claimed in
at least one of the claims \ to 12, wherein the security element (1) is
produced according to at least one of the claims 19 to 23 and the security
element produced in such a way is put on an object.
25. Method for producing an object with a security element (1) as claimed in
at least one of the claims 1 to 12, wherein the security element is produced
according to at least one of the claims 19 to 23 and wherein the security
element (1) produced in such a way is embedded in paper.
26. Method as claimed in claim 25, wherein the security element (1) is
embedded in the paper in the fashion of a window thread.
Security element for objects, in particular for documents of value such
as bank notes and credit cards, comprising several layers (I, R, M) located on top
of each other, namely at least one a color shift effect producing interference
element (I) and a layer (M) with magnetic properties, characterized in that a
reflection layer (R) is disposed between the layer (M) with magnetic properties and
the at least one interference element (I), wherein the layer (M) with magnetic
properties and the reflection layer have gaps (10, 20) in the form of symbols or
patterns or codings.
913-kolnp-2004-granted-reply to examination report.pdf
913-kolnp-2004-granted-translated copy of priority document.pdf
913-kolnp-2004-petition under rule 137.pdf
913-kolnp-2004-reply to examination report.pdf
|Indian Patent Application Number||913/KOLNP/2004|
|PG Journal Number||07/2010|
|Date of Filing||29-Jun-2004|
|Name of Patentee||GIESECKE & DEVRIENT GMBH|
|Applicant Address||PRINZREGENTENSTRASSE 159, 81677 MUNCHEN|
|PCT International Classification Number||B42D 15/10|
|PCT International Application Number||PCT/EP2003/00447|
|PCT International Filing date||2003-01-17|