Note: Descriptions are shown in the official language in which they were submitted.
CA 02907989 2015-09-23
Security element, production method, data carrier equipped with the security
element and method for checking the authenticity
[0001] This invention concerns a security element for data carriers, in
particular for value documents, identity documents and the like. The invention
furthermore concerns 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.
[0002] 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 10-8 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
CA 02907989 2015-09-23
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, of which each region
contains a material or a combination of materials, with the two or more
regions
showing substantially the same visible color under first viewing conditions
which
comprise visible light, and different visible colors under second viewing
conditions, with the second viewing conditions comprising 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, of which each region contains a material
or
a combination of materials, with the two or more regions showing different
visible
colors under first viewing conditions which comprise visible light, and
substantially the same visible colors under second viewing conditions, with
the
second viewing conditions comprising 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 defined in the main
claim. 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
defined
in the equal-ranking claims. Developments of the invention are the subject
matter
of the subclaims.
2
CA 02907989 2015-09-23
=
Summary of the invention
1. (First aspect) A security element for a data carrier, in particular a value
document, comprising a carrier substrate whose front side has a macroscopic
motif
composed of a multiplicity of microscopic single elements, wherein:
the microscopic single elements respectively contain at least three, in
particular four, neighboring regions produced by printing technology which are
so
constituted that the viewer perceives a so-called first light/medium/dark
contrast
within each single element under first viewing conditions, perceives a
substantially uniform lightness within each single element under second
viewing
conditions, and perceives a so-called second light/medium/dark contrast which
is
inverted compared to the first light/medium/dark contrast within each single
element under third viewing conditions; and
the microscopic single elements arouse in the viewer a dynamic impression
of the macroscopic motif 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.
2. (Preferred) The security element according to item 1, wherein the
microscopic
single elements composing the macroscopic motif are arranged in the form of a
planar cascade, and the term cascade is understood to be an arrangement of
successively placed single elements.
3. (Preferred) The security element according to item 2, wherein the
microscopic
single elements are arranged so as to be successively placed in a linear,
straight,
circular or wavy form within the planar cascade.
3
CA 02907989 2015-09-23
=
=
4. (Preferred) The security element according to either of items 2 to 3,
wherein the
planar cascade comprises a plurality of arrangements of microscopic single
elements in which the microscopic single elements are respectively arranged so
as
to be successively placed in a linear, straight, circUlar or wavy form, and
the
arrangements of the microscopic single elements are so configured that the
dimensions of the microscopic single elements are uniform within an
arrangement
but vary from arrangement to arrangement, in particular increasing and/or
decreasing continuously in one direction.
5. (Preferred) The security element according to any of items 1 to 4, wherein
the
microscopic single elements possess a size of at least 0.1 mm x 0.2 mm and at
most 5 mm x 10 mm, preferably a size of at least 1 mm x 2 mm and at most 3 mm
x 5 mm.
6. (Preferred) The security element according to any of items 1 to 5, wherein
the
single elements are configured in the form of plane figures, in particular
polygons,
circles, cycloid figures or parts of a circle.
7. (Preferred) The security element according to any of items 1 to 6, wherein
the
microscopic single elements respectively contain three neighboring regions
produced by printing technology, of which exactly one region has a luminescent
material which is invisible upon illumination with visible light and shows a
light
visible color upon illumination with ultraviolet light. The luminescent
material can
be e.g. mixed into a daylight color. According to an alternative, the
luminescent
material and a daylight color can be present printed side by side in a
halftone
manner, so that the luminescent material is not mixed into the daylight color.
According to a further alternative, the daylight color is present in a printed
layer
above which a further printed layer having the luminescent material is
applied.
8. (Preferred) The security element according to any of items 1 to 6, wherein
the
microscopic single elements respectively contain four neighboring regions
produced by printing technology, of which exactly two regions have a
luminescent
4
CA 02907989 2015-09-23
=
material which is invisible upon illumination with visible light and shows a
light
visible color upon illumination with ultraviolet light. The luminescent
material can
be e.g. mixed into a daylight color. According to an alternative, the
luminescent
material and a daylight color can be present printed side by side in a
halftone
manner, so that the luminescent material is not mixed into the daylight color.
According to a further alternative, the daylight color is present in a printed
layer
above which a further printed layer having the luminescent material is
applied.
9. (Preferred) The security element according to any of items 1 to 7, wherein
the
microscopic single elements respectively contain three neighboring regions
produced by printing technology, of which:
a first region has a first color layer in a dark 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 light visible color upon illumination with
ultraviolet
light;
a second region has a color layer in a medium or medium-dark visible color;
and
a third region has a color layer in a light visible color.
10. (Preferred) The security element according to any of items 1 to 7, wherein
the
microscopic single elements respectively contain three neighboring regions
produced by printing technology, of which:
a first region has a color layer and the color layer contains a material in a
dark visible color and a further material luminescing under UV irradiation
which
is invisible upon illumination with visible light and shows a light visible
color
upon illumination with ultraviolet light;
a second region has a color layer in a medium or medium-dark visible color;
and
a third region has a color layer in a light visible color.
CA 02907989 2015-09-23
=
11. (Preferred) The security element according to any of items 1 to 6 or item
8,
wherein the Microscopic single elements respectively contain four neighboring
regions produced by printing technology, of which:
a first region has a first color layer in a very dark 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 light visible color upon illumination with
ultraviolet
light;
a second region has a first color layer in a dark 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 light visible color upon illumination with
ultraviolet
light;
a third region has a color layer in a medium or medium-dark visible color;
and
a fourth region has a color layer in a light visible color.
12. (Preferred) The security element according to any of items 1 to 6 or item
8,
wherein the microscopic single elements respectively contain four neighboring
regions produced by printing technology, of which:
a first region has a color layer and the color layer contains a material in a
very dark visible color and a further material luminescing under UV
irradiation
which is invisible upon illumination with visible light and shows a light
visible
color upon illumination with ultraviolet light;
a second region has a color layer and the color layer contains a material in a
dark visible color and a further material luminescing under UV irradiation
which
is invisible upon illumination with visible light and shows a light visible
color
upon illumination with ultraviolet light;
a third region has a color layer in a medium or medium-dark visible color;
and
a fourth region has a color layer in a light visible color.
6
CA 02907989 2015-09-23
13. (Preferred) The security element according to any of items 7 to 12,
wherein the
luminescent material is a fluorescent material, in particular a fluorescent
ink or a
fluorescent pigment.
14. (Second aspect) A data carrier, comprising a security element according to
any
of items 1 to 13.
15. (Preferred) The data carrier according to item 14, wherein the data
carrier is a
value document, in particular a bank note, an identity document or a label.
16. (Third aspect) A method for manufacturing a security element according to
any of items 1 to 13, comprising the step of supplying a carrier substrate and
the
step of producing microscopic single elements on the front side of the carrier
substrate by printing technology, in particular by means of offset,
flexographic,
screen, gravure, intaglio or ink-jet printing.
17. (Fourth aspect) A method for checking the authenticity of a data carrier,
in
particular a value document, according to item 14 or 15, comprising the step
of
visually detecting the dynamic impression, defined in item 1, of the
macroscopic
image 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
[0006] The term "ultraviolet light" employed herein designates in
particular
light with a wavelength in a region of 235 to 380 nm.
[0007] Instead of the term "visible light" the term "daylight" will also be
employed hereinafter.
[0008] 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.
7
CA 02907989 2015-09-23
[0009] 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 picture information.
[0010] The term "plane figure" is known in the prior art (see
"Mathematische
Formelsammlung" (Mathematics Formulary), 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 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).
[0011] The term "polygon" employed herein designates in particular an n-gon
with n? 3.
[0012] The term "microscopic" employed herein is not to be understood in
terms of "dimension in the micrometer region" or the like, but is rather to be
understood merely relatively. The microscopic single elements (which will
hereinafter also be designated simply "microelements") are respectively
perceptible to the viewer with the naked eye, i.e. without employing optical
aids,
and compositely yield a total image, i.e. a macroscopic motif.
[0013] The invention is based on the idea of achieving a dynamic effect in
a
micro-/macroimage 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 recurrent microelement structure contained in the macroscopic motif and
can
8
CA 02907989 2015-09-23
be observed in particular upon an oscillating traversal (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.
The thus created play of light of the microscopic single elements causes a
dynamics in the macroscopic motif. 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 a lightness change of closely
adjacent
motif elements, e.g. lines, dots or circles. The lightness change is produced
by the
change of the distance between the UV light source and the security element,
with
the luminosity 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.
[0014] The dynamic motion effect comes about, depending on the choice and
arrangement of the microelements, e.g. 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 microelements together such that they
together yield a pattern with rotational symmetry, in particular a pattern
with
rotational symmetry and mirror symmetry. The microelements can be joined
together in gapless relationship or in spaced relationship. For example, white
regions or unprinted regions can be present between the individual
microelements.
[0015] Suitable for carrying out the invention are in particular
fluorescent
pigments and fluorescent dyes (in particular organic color matters) whose
optical
9
CA 02907989 2015-09-23
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
within 10-8 seconds. Phosphorescent materials are 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.
[0016] 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.
[0017] 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
illustrative value.
[0018] Specifically, the figures show:
Figures 1 to 15: the embodiment variant of a security element that does not
fall
within the scope of the present claims; this embodiment variant
is mentioned merely for better comprehension of the present
invention;
Figure 16: an embodiment variant of a security element according to the
present invention;
Figures 17 to 20: four examples for producing microscopic single elements of
which the macroscopic motif according to Fig. 16 can be
composed.
CA 02907989 2015-09-23
[0019] Fig. 10 illustrates the construction of a security element in a
cross-
sectional view. The shown security element does not fall within the scope of
the
present claims, but the shown embodiment variant is mentioned for better
comprehension of the present invention.
[0020] The present invention is founded on the principle of a dynamic
interplay of colors which is obtained by combining a daylight color with a
luminescent color. These foundations will be described with reference to
Figures 1
to 15.
[0021] Figure 10 illustrates a carrier substrate, for example the paper
substrate
of a bank note, which 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
elements respectively comprising only a 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
[0022] The yellow fluorescent color of the color layer 3 is invisible upon
viewing solely in daylight and appears yellow upon viewing in UV light.
[0023] Figures 1 to 3 show in plan view the structure of the printing forms
for
manufacturing the security element 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.
11
CA 02907989 2015-09-23
=
[0024] 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 derives solely from 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.
[0025] 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.
[0026] 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.
[0027] Fig. 7 shows the security element of Fig. 10 in plan view upon
viewing
under daylight and UV light in a ratio of about 1:1. In the regions 11 the
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.
[0028] 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.
[0029] 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.
[0030] 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
12
CA 02907989 2015-09-23
=
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.
[0031] 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.
[0032] 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
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.
[0033] Figures 8 (plan view) and 14 (cross-sectional view) 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.
[0034] 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.
13
CA 02907989 2015-09-23
=
< Exemplary embodiment 1>
[0035] Fig. 16 shows a macroscopic motif 15 in which many single elements
16 are arranged in the form of a planar cascade. A cascade is understood to be
an
arrangement of successively placed, like-kind graphical elements.
[0036] Upon planar, multiple arrangement of the single elements the
impression of a motion is produced by a lightness shift (i.e. an inversion or
reversal of contrast). Depending on the arrangement of the single elements
within
the macroscopic motif and the constitution of the single elements, the
direction of
the motion can be varied.
[0037] Through the different lightness levels of the regions 17, 18 and 19
within a single element 16 a flowing motion effect in a certain direction is
obtained in the macroscopic motif 15.
[0038] In Fig. 16 the effect causes a rotation of the total image 15 in the
counter-clockwise direction.
[0039] The quality of the motion effect is dependent, inter alia, on
- the size of a cascade element 16,
- the luminous intensity of the UV lamp and the associated luminosity of
the
fluorescence,
- the contrast of the single elements 16 compared to the printed
environment,
- the lightness difference between UV lamp light and daylight, and
- the frequency at which the UV lamp is moved up and down, or back and
forth, above the printed element.
[0040] Since the motion effect can be brought about in different directions
depending on the arrangement of the elements 16, it is conceivable to produce
motion effects in different directions within a macroscopic motif (e.g. the
outer
ring shown in Fig. 16 produces a motion effect in the counter-clockwise
direction,
the next inner ring a motion effect in the clockwise direction, etc.).
14
CA 02907989 2015-09-23
[0041] The macroscopic motif 15 shown in Fig. 16 is composed of single
elements 16. The constitution of a single element, or rather of the regions
17, 18
and 19 contained therein, will be explained more closely with reference to
Figures
17a to 17d.
[0042] The single element shown in Fig. 17a has three regions A, B and C in
three different lightness levels. The regions are produced in the present
example
by halftone printing by means of daylight color, with a different area
coverage
being chosen per region. The single element shown in Fig. 17a contains three
regions with an area coverage of 10%, 50% and 100%, respectively. The darkest
region with an area coverage of 100% is additionally equipped with a
fluorescent
color 20 or is overprinted with fluorescent color 20.
[0043] Upon a change from daylight to UV light there occur a continuous
lightening of the darker region A overprinted with fluorescent color 20, on
the one
hand, and a darkening of the lighter regions B and C through shadowing by
means
of the UV lamp housing or the UV lamp (including the hand in the case of UV
hand lamps), on the other hand.
[0044] The abbreviations d (dark), m (medium or medium-dark) and h (light)
present in Figures 17 to 19 describe the lightness of the individual regions,
with
the abbreviations being classified with increasing lightness as follows:
d: dark;
d-m: dark to medium;
m: medium;
m-h: medium to light;
h: light.
[0045] Fig. 17b shows the lightnesses of the regions A, B and C of the
single
element upon viewing in daylight.
CA 02907989 2015-09-23
4 =
[0046] Fig. 17c shows the lightnesses of the regions A, B and C of the
single
element upon viewing upon illumination with a combination of daylight and UV
light in substantially equal parts.
[0047] Fig. 17d shows the lightnesses of the regions A, B and C of the
single
element upon viewing in UV light.
[0048] In daylight the area C is the lightest, A the darkest. In the half-
and-half
situation the darkest area becomes somewhat lighter, the lightest somewhat
darker.
The total area appears virtually in a more or less uniform gray. Under UV
light the
area A is the lightest, the area B the darkest. This lightness shift from C to
A
arouses in the viewer the impression that the area is moving accordingly from
the
right to the left.
< Exemplary embodiment 2>
[0049] In this example the macroscopic motif 15 shown in Fig. 16 is
composed
of single elements 16, with the constitution of a single element, or rather of
the
regions 17, 18 and 19 contained therein, being explained more closely with
reference to Figures 18a to 18d.
[0050] The single element shown in Fig. 18a has four regions A, B, C and D
in
four different lightness levels. The regions are produced in the present
example by
halftone printing by means of daylight color, with a different area coverage
being
chosen per region. The single element shown in Fig. 18a contains four regions
with an area coverage of 10%, 40%, 70% and 100%, respectively. The darkest
region with an area coverage of 100% and the second-darkest region with an
area
coverage of 70% are respectively additionally equipped with a fluorescent
color
21 or are overprinted with fluorescent color 21.
[0051] Upon a change from daylight to UV light there occur a continuous
lightening of the darker regions A and B overprinted with fluorescent color
21, on
the one hand, and a darkening of the lighter regions C and D through shadowing
16
CA 02907989 2015-09-23
4 =
by means of the UV lamp housing or the UV lamp (including the hand in the case
of UV hand lamps), on the other hand.
[0052] Fig. 18b shows the lightnesses of the regions A, B, C and D of the
single element upon viewing in daylight.
[0053] Fig. 18c shows the lightnesses of the regions A, B, C and D of the
single element upon viewing upon illumination with a combination of daylight
and
UV light in substantially equal parts.
[0054] Fig. 18d shows the lightnesses of the regions A, B, C and D of the
single element upon viewing in UV light.
[0055] In daylight, area D is the lightest, area C the second-lightest,
area B the
darkest and area A the second-darkest. Through the lightening of the two dark
regions A and B under the UV lamp with simultaneous darkening of the light
regions C and D, the total area appears in a more or less uniform gray in the
half-
and-half situation.
[0056] Under UV light this effect is strengthened further, so that position
A
appears as the lightest area, and position B as the second-lightest. This
lightness
shift from D to A arouses in the viewer the impression that the area is moving
accordingly from the right to the left.
< Exemplary embodiment 3>
[0057] According to a variant of the case described in exemplary embodiment
2, further arrangements of the gray-level fields within a single element 16
shown
in Fig. 16 are conceivable.
[0058] Fig. 19a shows the lightnesses of the regions A, B, C and D of the
single element upon viewing in daylight.
17
CA 02907989 2015-09-23
. .
t =
. [0059] Fig. 19b shows the lightnesses of the regions A, B, C and D of the
single element upon viewing upon illumination with a combination of daylight
and
UV light in substantially equal parts.
[0060] Fig. 19c shows the lightnesses of the regions A, B, C and D of the
single element upon viewing in UV light.
[0061] In general, the realization of a single element can be carried out
via any
form of halftoning of a single color or as a multicolor print of different
gray levels
or color tones of different lightness or also by means of partial overprinting
of two
color tones.
[0062] When the motif is printed in a halftone manner, the coverage ratio
changes accordingly, since in this case no 100% area coverage can be present.
In
this case a maximum area coverage of 70 to 80% is obtained.
[0063] Manufacture is in principle process-independent, i.e. one can
proceed
e.g. by means of offset printing, intaglio printing, screen printing or
flexographic
printing. The printing methods can likewise be combined with each other, e.g.
daylight color by offset, intaglio or screen printing, and fluorescent color
by ink-
jet, screen or flexographic printing.
< Exemplary embodiment 4>
[0064] In this example the macroscopic motif 15 shown in Fig. 16 is
composed
of single elements 16, with the constitution of a single element, or rather of
the
regions 17, 18 and 19 contained therein, being explained more closely with
reference to Figures 20a and 20b.
[0065] Fig. 20a shows the partial overprint of different-colored areas 22
and
23 of different lightness. Area 22 is blue, and area 23 light-green. The
fluorescent
color is in this example printed congruently over the blue area 22 or can be
mixed
thereinto. The paper-white serves as the lightest area (with an area coverage
or
gray level of 10%).
18
CA 02907989 2015-09-23
4 õ
[0066] Fig. 20b
shows the overprint which has the blue area 24, the dark-blue
area 25, the light-green area 26 and the white area 27.
19
