Note: Descriptions are shown in the official language in which they were submitted.
CA 02886604 2015-03-30
Security element, manufacturing method, data carrier equipped with said
security
element, and method for checking authenticity
100011 This invention relates to a security element for data carriers, in
particular for value documents, identity documents and the like. The invention
relates furthermore to a data carrier equipped with the security element, a
method
for checking the authenticity of the data carrier, and a method for
manufacturing
the security element.
100021 For protection against imitation, in particular with color copiers
or
other reproductive methods, data carriers, such as bank notes, papers of
value,
credit cards, identity documents, passports, deeds and the like, labels,
packages or
other elements for product authentication are equipped with luminescent
security
elements. These include fluorescent fibers or planchets (small colored disks)
which are mixed into the paper pulp as a security feature during paper
manufacture. Furthermore, there are employed fluorescent security threads made
of plastic, metal or another material which are embedded wholly or partly into
the
paper during paper manufacture. It is also known to employ fluorescent
imprints
which are invisible or colorless in normal light but fluoresce under UV light.
Fluorescence is understood in general to be a short-lived light emission
ending
within 104 seconds. Instead of fluorescent printing inks there are also
employed
phosphorescent or photochromic printing inks. With phosphorescent materials,
the
luminous effect continues from 10-8 seconds up to several seconds or hours
after
the end of irradiation, depending on the material. Photochromic printing ink
changes its color upon excitation with UV light. When the UV light source is
removed, the color change continues for a time before the color changes back
to
the original state again. A special case of a photochromic printing ink is
iridescent
photochromic printing ink. Iridescent or pearl-effect inks contain transparent
pigments consisting of tiny mica flakes covered with thin foil. They cause an
interference of the irradiating light. This gives rise to lustrous, pearl-like
1
shimmering effects with a color-tone change at different viewing angles or
illumination angles.
[0003] From EP 1 567 358 B1 there is known a luminescent security
element
for securing bank notes which has two or more regions, each region containing
a
material or a combination of materials, wherein the two or more regions show
substantially the same visible color under first viewing conditions which
comprise
visible light, and different visible colors under second viewing conditions,
wherein the second viewing conditions comprise a combination of visible light
and UV light (see claim 1 of EP 1 567 358 B1). Further, there is known from EP
1
567 358 B1 a luminescent security element for securing bank notes which has
two
or more regions, each region containing a material or a combination of
materials,
wherein the two or more regions show different visible colors under first
viewing
conditions which comprise visible light, and substantially the same visible
colors
under second viewing conditions, wherein the second viewing conditions
comprise a combination of visible light and UV light (see claim 2 of EP 1 567
358
B1).
[0004] Starting out from the above prior art, the present invention is
based on
the object of providing a security element of the type stated at the outset
which
offers an elevated measure of anti-forgery security and at the same time can
be
checked for authenticity in a simple manner. Furthermore, there are to be
provided
a data carrier having such a security element and a method for manufacturing
such
a security element.
[0005] This object is achieved by the security element disclosed in this
application. A method for manufacturing the same, a data carrier having such a
security element and a method for checking the authenticity of the data
carrier are
disclosed in this application. Developments of the invention are also
disclosed in
this application.
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Summary of the invention
[0006] 1. (First
aspect) A security element for a data carrier, in particular a
value document, comprising a carrier substrate whose front side has first
motif
elements and second motif elements, wherein:
the first motif elements show a darker color than the second motif elements
under first viewing conditions, so that the viewer perceives the first and
second
motif elements in the form of a light/dark contrast designated a first motif;
the first motif elements and the second motif elements show a substantially
uniform, visible color and form a second motif under second viewing
conditions;
the first motif elements show a lighter color than the second motif elements
under third viewing conditions, so that the viewer perceives the first and
second
motif elements in the form of a light/dark contrast that is inverted compared
to the
light/dark contrast of the first motif and designated a third motif; wherein
the first motif and the third motif create for the viewer the impression of a
motion image upon an oscillating change between the first and the third
viewing
conditions, and the first, second and third viewing conditions are defined as
follows:
first viewing conditions: viewing upon illumination with visible light;
second viewing conditions: viewing upon illumination with a combination of
visible light and ultraviolet light in substantially equal parts;
third viewing conditions: viewing upon illumination with ultraviolet light.
[0007] In
particular, in addition to the first motif elements and second motif
elements there can also be present white regions, i.e. unprinted or
substantially
unprinted regions.
[0008] 2.
(preferred) The security element according to paragraph 6, wherein
the first and second motif elements are disposed offset.
[0009] The first
motif elements and the second motif elements can furthermore
be mutually separated by white regions, i.e. unprinted or substantially
unprinted
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regions. For example, a recurrent arrangement of "first motif element ¨ second
motif element ¨ white region ¨ first motif element ¨ second motif element ¨
white
region" can be present.
100101 3. (preferred) The security element according to paragraph 6 or
8,
wherein:
the first motif elements respectively have a first color layer in a first
visible
color and a second color layer formed above the first color layer, and the
second
color layer contains a material luminescing under UV irradiation which is
invisible
upon illumination with visible light and shows a second visible color upon
illumination with ultraviolet light;
the second motif elements respectively have a color layer in a third visible
color; and
the two color layers of the first motif elements are so coordinated that the
first and second visible colors yield under the second viewing conditions a
mixed
color which is substantially identical with the third visible color of the
second
motif elements.
[0011] 4. (preferred) The security element according to paragraph 6 or
8,
wherein:
the first motif elements respectively have a color layer and the color layer
contains a material in a first visible color and a further material
luminescing under
UV irradiation which is invisible upon illumination with visible light and
shows a
second visible color upon illumination with ultraviolet light;
the second motif elements respectively have a color layer in a third visible
color; and
the two materials in the color layer of the first motif elements are so
coordinated that the first and second visible colors yield under the second
viewing
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conditions a mixed color which is substantially identical with the third
visible
color of the second motif elements.
[0012] The visible colors mentioned in the preceding paragraph (i.e. the
first,
second and third visible colors) differ in particular in their color tone or
in their
lightness.
[0013] 5. (preferred) The security element according to any one of
paragraphs
6 to 11, wherein the first and second motif elements are configured in the
form of
two segment groups disposed offset, in particular in the form of two grids
disposed offset.
[0014] 6. (preferred) The security element according to paragraph 13,
wherein
the first and second motif elements are configured in the form of two grids
disposed offset and at least one of the two grids has recurrent grid regions,
wherein the line thickness of the individual grid elements varies, in
particular
increases or decreases continuously in one direction, within the recurrent
grid
region.
[0015] 7. (preferred) The security element according to any one of
paragraphs
6 to 14, wherein the first and second motif elements are configured
independently
of each other in the form of plane figures, in particular polygons, circles,
cycloid
figures or parts of a circle, and the first and second motif elements are
disposed
altematingly.
[0016] 8. (preferred) The security element according to paragraph 15,
wherein
at least one of the two types of altematingly disposed, plane figures has
recurrent
regions in which the dimensions of the individual plane figures vary, in
particular
increase or decrease continuously in one direction.
[0017] 9. (preferred) The security element according to any one of
paragraphs
6 to 11, wherein the first or the second motif elements are configured in the
form
of plane figures disposed in spaced relationship, in particular polygons,
circles,
CA 2886604 2019-10-01
cycloid figures or parts of a circle, and the further motif elements produce a
background.
[0018] 10. (preferred) The security element according to paragraph 17,
wherein the plane figures disposed in spaced relationship have recurrent
regions in
which the dimensions of the individual plane figures vary, in particular
increase or
decrease continuously in one direction.
[0019] 11. (preferred) The security element according to any one of
paragraphs
to 18, wherein the luminescent material is a fluorescent material, in
particular a
fluorescent ink or a fluorescent pigment.
[0020] 12. (Second aspect) A data carrier, comprising a security element
according to any one of paragraphs 6 to 19.
[0021] 13. (preferred) The data carrier according to paragraph 20,
wherein the
data carrier is a value document, in particular a bank note, an identity
document or
a label.
[0022] 14. (Third aspect) A method for manufacturing a security element
for a
data carrier, in particular a value document, comprising the step of supplying
a
carrier substrate and the step of producing first and second motif elements on
the
front side of the carrier substrate by printing technology, in particular by
means of
offset printing, flexographic printing, screen printing, gravure printing,
intaglio
printing or ink-jet printing, wherein the first and second motif elements are
constituted as follows:
the first motif elements show a darker color than the second motif elements
under first viewing conditions, so that the viewer perceives the first and
second
motif elements in the form of a light/dark contrast designated a first motif;
the first motif elements and the second motif elements show a substantially
uniform, visible color and form a second motif under second viewing
conditions;
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the first motif elements show a lighter color than the second motif elements
under third viewing conditions, so that the viewer perceives the first and
second
motif elements in the form of a light/dark contrast that is inverted compared
to the
light/dark contrast of the first motif and designated a third motif; wherein
the first motif and the third motif create for the viewer the impression of a
motion image upon an oscillating change between the first and the third
viewing
conditions, and the first, second and third viewing conditions are defined as
follows:
first viewing conditions: viewing upon illumination with visible light;
second viewing conditions: viewing upon illumination with a combination of
visible light and ultraviolet light in substantially equal parts;
third viewing conditions: viewing upon illumination with ultraviolet light.
[0023] 15. (Fourth aspect) A method for checking the authenticity of a
data
carrier, in particular a value document, according to paragraph 20 or 21,
comprising the step of visually detecting the motion image defined in
paragraph 6
by viewing the data carrier in daylight with the aid of a UV light source, in
particular a UV hand lamp, with the distance between data carrier and UV light
source being shortened and lengthened again in recurrent succession.
Detailed description of the invention
[0024] The term "ultraviolet light" employed herein designates in
particular
light with a wavelength in a region of 235 to 380 nm.
[0025] Instead of the term "visible light" the term "daylight" will also
be
employed hereinafter.
[0026] The term "daylight color'' is understood to be a color based on
light in a
wavelength region of 380 nm to 750 nm. Hereinafter the synonyms body color and
chromatic color will also be employed.
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[00271 The term "motif is understood to be in particular a pattern or an
image.
The motif can furthermore convey information to the viewer by having e.g. a
character, a character string or a picture information. In a variant, the
information
is perceptible to the viewer in ultraviolet light and imperceptible in pure
visible
light, or vice versa.
[0028] The three hereinabove mentioned motifs (i.e. the "first", "second"
and
"third" motif) are visually distinguishable to the viewer.
[0029] A segment can be understood to be e.g. a plane figure. The term
"plane
figure" is known in the prior art (see "Mathematische Formelsammlung", Verlag
Konrad Wittwer KG, Stuttgart, 1984, pages 12-15). Plane figures include in
particular the following elements: triangle, in particular right-angled
triangle,
isosceles triangle and equilateral triangle; quadrangle, in particular square,
rectangle, rhombus, parallelogram, kite, trapezoid, cyclic quadrilateral and
tangential quadrilateral; circle; cycloid figures, such as e.g. an ellipse;
parts of a
circle, in particular circular sector (a circular sector can be defined by the
parameters r = radius, b = arc and a = central angle), annulus (an annulus can
be
defined by the parameters r = radius of the inner circle and R = radius of the
outer
circle) and annulus sector (an annulus sector can be defined by the parameters
r =
radius of the inner circle, R = radius of the outer circle, B = outer arc, b =
inner arc
and a = central angle).
[0030] The term "polygon" employed herein designates in particular an n-gon
with n? 3.
[0031.1 The invention is based on the idea of achieving a dynamic effect
through the interaction of luminous colors or luminescent colors, in
particular
fluorescent colors, and body colors or chromatic colors by means of a suitable
design. The dynamic effect is based on a light/dark interaction of a motif-
element
structure contained in the motif, and can be observed in particular upon an
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oscillating traversing (i.e. through a periodic "back-and-forth") of the
transition
from (1) the illumination of the security element with visible light, through
(2) a
UV light/daylight illumination situation in an approximate ratio of 1:1, to
(3) a
substantially pure UV illumination situation. What is decisive for the dynamic
effect is the periodic change of the distance between the UV light source and
the
security element. The percentage ratio of daylight to UV light changes here in
particular in a region of 70/30 to 30/70. Since the human eye regards the
lighter
image components of a motif as being in the foreground or dominant, the
dynamic
motion effect is especially impressive upon the change of lightness of closely
adjacent motif elements, e.g. lines, dots or circles. The change of lightness
is
produced by the change of the distance between the UV light source and the
security element, with the illuminance e.g. of a fluorescent color increasing
quadratically as the distance is shortened. Thus, at a greater distance the
lighter
daylight color becomes dominant, and at a smaller distance the fluorescent
color,
which otherwise appears darker in daylight.
[00321 The dynamic motion effect comes about, depending on the choice and
arrangement of the motif elements, in the form of a turning or rotation effect
(i.e.
the motion of a turning wheel) created by an optical illusion, or in the form
of a
"pumping effect" (i.e. the periodically changing three-dimensional appearance
of a
motif) otherwise known in holograms, or the like. A turning or rotation effect
can
be brought about e.g. by joining the first and second motif elements together
in an
alternating manner such that they together yield a pattern with rotational
symmetry, in particular a pattern with rotational symmetry and mirror symmetry
(see e.g. the pattern in Fig. 17). The first and second motif elements can be
joined
together in gapless relationship or in spaced relationship.
[0033] Suitable for carrying out the invention are in particular
fluorescent
pigments and fluorescent dyes (in particular organic color matters) whose
optical
effect is based on their ability to absorb UV radiation and emit it in the
form of
visible light without a time delay, i.e. with a short-lived light emission
ending
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within 10-8 seconds. Phosphorescent materials arc less preferred, but can be
used
on condition that the duration of the afterglow process does not impair the
recognizability of the dynamic motion effect.
[0034] The security element according to the invention can be excitable in
particular at two or more wavelengths and then show different fluorescent
color
tones in dependence on the wavelength.
[0035] The invention will be explained more closely with reference to the
following embodiment variants or examples in connection with the accompanying
figures. The examples represent preferred embodiments, but the invention
should
in no way be limited thereto. Furthermore, the representations in the figures
are
strongly schematic for the sake of better comprehension and do not reflect the
actual conditions. In particular, the proportions shown in the figures do not
correspond to the relations existing in reality and serve exclusively to
improve the
clearness.
[0036] Specifically, the figures show:
Figures Ito 15: a first embodiment variant of the invention;
Figures 16 to 22: further embodiment variants of the invention.
[0037] Fig. 10 illustrates the construction of a security element according
to
the invention according to a first embodiment variant in a cross-sectional
view. A
carrier substrate, for example the paper substrate of a bank note (not shown
in the
figure), has on its front side first motif elements (regions with the
reference
numbers 1 and 3) and second motif elements (regions with the reference number
2). The first and second motif elements are respectively formed by color
layers
produced by printing technology, with the first motif elements respectively
containing a lower color layer 1 and an upper color layer 3 and the second
motif
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elements respectively comprising only one color layer 2. The color layers
possess
the following properties:
Color layer 1: dark blue daylight color
Color layer 2: light green daylight color
Color layer 3: yellow fluorescent color
[0038] The yellow fluorescent color of the color layer 3 is invisible upon
viewing solely in daylight and appears yellow upon viewing in UV light.
[0039] Figures 1 to 3 show in plan view the structure of the printing forms
for
manufacturing the security elements shown in Fig. 10. The printing form shown
in
Fig. 1 is provided for producing the color layer 1 in dark blue daylight
color. Fig.
2 shows the printing form for producing the color layer 2 in light green
daylight
color. Fig. 3 shows the printing form for producing the color layer 3 in
yellow
fluorescent color.
[0040] Fig. 4 illustrates the construction of the combination print that is
obtainable through the printing forms shown in Figures 1 to 3. The combination
print has an outer, rectangular border 4 and an inner region 5. The printing
ink of
the rectangular border 4 is due solely to the printing form shown in Fig. 1.
The
inner region 5 contains a background print produced by the printing forms of
Fig.
1 and Fig. 2 and a plurality of regions overprinted by means of the printing
form
of Fig. 3.
[0041] Fig. 5 shows the security element of Fig. 10 in plan view upon
viewing
in pure daylight. The viewer perceives a first information item formed by
vertical,
light green stripes 7 and a dark blue background 6.
[0042] Fig. 6 shows the security element of Fig. 10 in plan view upon
viewing
substantially in pure UV light. The viewer perceives a second information item
formed by vertical, yellow stripes 10 and a very dark background 9.
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[0043] Fig. 7 shows the security element of Fig. 10 in plan view upon
viewing
in daylight and UV light in a ratio of about 1:1. In the regions lithe yellow
fluorescent color mixes with the dark blue daylight color located therebelow
through additive color mixture to form a green corresponding to the daylight
green
of the regions 12. There thus arises, as a third information item, an area
that is
single-colored to the eye.
[0044] How the motifs shown in Figures 5, 6 and 7 come about is illustrated
by the cross-sectional views shown in Figures 11, 12 and 13.
[0045] Fig. 11 shows the security element of Fig. 5 in pure daylight. The
reference number 8 designates the color layers formed with fluorescent color
which are invisible under the present viewing conditions. The reference
numbers 6
and 7 indicate the visible color layers formed with dark blue and light green
daylight color, respectively.
[0046] Fig. 12 shows the security element of Fig. 6 in pure UV light. The
reference number 10 designates the color layers formed with yellow fluorescent
color which are visible under the present viewing conditions. The reference
number 9 indicates the color layers formed with daylight color which are
invisible
under the present viewing conditions.
[0047] Fig. 13 shows the security element of Fig. 7 upon viewing under
daylight/UV light in a ratio of about 1:1. The reference number 11 designates
the
green recognizable to the viewer through additive color mixture of the yellow
fluorescent color and the dark blue daylight color. The reference number 12
indicates the green formed by daylight color which is visible to the viewer.
[00481 The dynamic interplay of light in the course of the periodic motion
of
the UV light source is illustrated by Figures 8, 9, 14 and 15. As the distance
between UV light source and object decreases the lightness of the fluorescent
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=
color increases, while conversely decreasing as said distance increases.
Compared
to the fluorescent color, the lightness of the daylight colors changes in an
opposite
manner through decreasing of the daylight portion when the object enters a UV
chamber or through shadowing by means of a UV hand lamp sliding above the
object. In other words, as the distance from the UV lamp decreases the
fluorescent
color becomes lighter than the daylight color, while as said distance
increases the
daylight color becomes lighter than the fluorescent color again.
[0049] Figures 8 (plan view) and 14 (cross-sectional views) show the
security
element of Fig. 10 upon viewing under daylight/UV light in a ratio of about
1:2.
The regions with the reference number 13 are perceived by the viewer with
light
green color, while the regions with the reference number 14 are perceived with
dark green color.
100501 Figures 9 (plan view) and 15 (cross-sectional view) show the
security
element of Fig. 10 upon viewing under daylight/UV light in a ratio of about
2:1.
The regions with the reference number 13 are perceived by the viewer with dark
green color, while the regions with the reference number 14 are perceived with
light green color.
[0051] Figures 16 to 22 show further design implementations of the security
element shown in Fig. 10.
[0052] Fig. 16 shows an arrangement of the first and second motif elements
in
the form of two offset grids (which are represented by black and white lines
in the
figure), with the grid elements having the form of concentric, star-shaped
formations.
[0053] Fig. 17 shows an alternating, circular arrangement of first and
second
motif elements which respectively have the approximate form of an isosceles
triangle.
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[00541 In a variant for the embodiment shown in Fig. 17, the intermediate
lines
or sides of the isosceles triangles are formed by alternating first and second
motif
elements. A variation of the line thickness can additionally intensify the
dynamic
motion effect.
100551 Fig. 18 shows the formation of a snail shell in which the circularly
disposed white areal elements represent the second motif elements, and the
black
intermediate lines between the circularly disposed white areal elements
represent
the first, fluorescent motif elements.
100561 The examples according to Figures 17 and 18 show an impressive
rotation effect as the UV light source moves.
100571 In the examples according to Figures 19 and 20, the first and second
motif elements are configured in the form of two grids disposed offset, with
one
of the two grids having periodically recurring grid regions. Within the
recurrent
grid region the line thickness of the individual grid elements varies, i.e. it
increases or decreases continuously in one direction. Figures 19 and 20 show
only
one recurring unit of the periodically recurring grid region (black lines with
high
line width).
100581 In the example shown in Fig. 19, the line thickness increases in one
direction within the periodically recurring grid region; the distance between
the
lines decreases in the same direction.
[0059] In the example shown in Fig. 20, both the line thickness and the
distance between the lines decrease in the same direction within the
periodically
recurring grid region.
100601 Fig. 21 and Fig. 22 respectively show an alternating, circular
arrangement of first motif elements 15 and second motif elements 16, with the
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arrangement additionally having white regions 17, in the present case
unprinted
regions.
[0061] In the embodiment variant shown in Fig. 10, the first motif elements
are respectively formed by a lower color layer containing a daylight color,
and an
upper color layer containing a fluorescent color. The construction in the form
of a
double layer is not necessary, however. According to a further variant, the
daylight
color and the fluorescent color can also be contained in a single color layer.
[0062] Furthermore, the security element according to the invention can
also
contain further types of motif elements apart from the first and second motif
elements. A conceivable design implementation is for example a security
element
having additional third motif elements similar to the first motif elements
shown in
Fig. 10 but with a different fluorescent or phosphorescent color.
