U.S. patent application number 10/579289 was filed with the patent office on 2007-04-19 for data carrier having identifiers.
Invention is credited to Gunter Endres, Georg Kruse, Josef Riedl.
Application Number | 20070087173 10/579289 |
Document ID | / |
Family ID | 34585064 |
Filed Date | 2007-04-19 |
United States Patent
Application |
20070087173 |
Kind Code |
A1 |
Endres; Gunter ; et
al. |
April 19, 2007 |
Data carrier having identifiers
Abstract
The invention relates to a data carrier into which, by means of
a laser beam, identifiers are introduced that are visible in the
form of irreversible changes, caused by the laser beam, in the
optical properties of the data carrier. According to the present
invention, the data carrier comprises a laser-sensitive layer (20)
that is opaque in the visible spectral range, and that is combined
with a securing layer (22) that is metallized at least in a
sub-area, the identifiers (30, 32) being introduced by the laser
beam simultaneously and in perfect register into the
laser-sensitive layer (20) and the metallized sub-area (24) of the
securing layer (22).
Inventors: |
Endres; Gunter; (Munich,
DE) ; Kruse; Georg; (Aschheim, DE) ; Riedl;
Josef; (Attenkirchen, DE) |
Correspondence
Address: |
K. David Crockett;Crockett & Crockett
24012 Calle de la Plata
Suite 400
Laguna Hills
CA
92653
US
|
Family ID: |
34585064 |
Appl. No.: |
10/579289 |
Filed: |
November 8, 2004 |
PCT Filed: |
November 8, 2004 |
PCT NO: |
PCT/EP04/12628 |
371 Date: |
May 12, 2006 |
Current U.S.
Class: |
428/203 |
Current CPC
Class: |
G07F 7/086 20130101;
B42D 25/45 20141001; G06K 1/126 20130101; B42D 25/373 20141001;
B42D 25/309 20141001; Y10T 428/24851 20150115; Y10T 428/24917
20150115; B41M 5/24 20130101; B42D 25/41 20141001; B42D 25/435
20141001; Y10T 428/24868 20150115; B42D 2033/10 20130101 |
Class at
Publication: |
428/203 |
International
Class: |
B32B 3/00 20060101
B32B003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 12, 2003 |
DE |
103 53 092.4 |
Claims
1. A data carrier into which, by means of a laser beam, identifiers
are introduced that are visible in the form of irreversible
changes, caused by the laser beam, in the optical properties of the
data carrier, characterized in that: the data carrier comprises a
laser-sensitive layer that is opaque in the visible spectral range
and that is combined in such a way with a securing layer that is
metallized at least in a sub-area that the two layers overlap at
the metallized sub-area of the securing layer, and the opaque,
laser-sensitive layer and the securing layer each include separate
identifiers, the identifiers being introduced by the laser beam
simultaneously and in register into the opaque, laser-sensitive
layer and the metallized sub-area of the securing layer.
2. The data carrier according to claim 1, characterized in that the
introduction of the identifiers into the securing layer occurs
through material ablation in the metallized sub-area.
3. The data carrier according to claim 1, characterized in that the
introduction of the identifiers into the securing layer occurs
through a local transformation of the metal into a transparent or
translucent modification.
4. The data carrier according to claim 1, characterized in that one
or more intermediate layers are disposed between the
laser-sensitive layer and the securing layer.
5. The data carrier according to claim 4, characterized in that the
intermediate layer(s) are colored and/or printed on and/or
fluoresce.
6. The data carrier according to claim 4, characterized in that the
intermediate layer(s) exhibit one or more apertures in the area of
the identifiers.
7. The data carrier according to claim 1, characterized in that the
metallized sub-area is vapor deposited on the securing layer.
8. The data carrier according to claim 1, characterized in that the
metallized sub-area is formed by a printing layer of a metallic
effect ink.
9. The data carrier according to claim 1, characterized in that the
metallized sub-area exhibits a diffraction pattern.
10. The data carrier according to claim 1, characterized in that
the laser-sensitive layer is formed by a plastic foil that is doped
at least in a sub-area.
11. The data carrier according to claim 1, characterized in that
the laser-sensitive layer is formed by a plastic foil that is
provided, at least in a sub-area, with a printing layer that
absorbs the laser radiation.
12. The data carrier according to claim 1, characterized in that
multiple laser-sensitive layers are provided that are opaque in the
visible spectral range.
13. The data carrier according to claim 1, characterized in that
the identifiers comprise a halftone pattern reproduced from an
original.
14. The data carrier according to claim 13, characterized in that
the halftone pattern is introduced in a screening technique,
different brightness levels of the halftone pattern being produced
by a different grid-point density, a different grid-point size
and/or by a different grid-point blackening.
15. The data carrier according to claim 1, characterized in that
the metallized sub-area, together with the opaque layer, displays,
in reflected light, a tilt effect in which the image impression of
the introduced identifiers switches from a positive image to a
negative image when the viewing angle changes.
16. The data carrier according to claim 1, characterized in that
multiple securing layers are provided that are metallized at least
in a sub-area, whereby the combination of metallized securing
layers in various levels achieves a spatial effect.
17. The data carrier according to claim 1, characterized in that
the or one of the metallized securing layers is additionally
provided with a laser-tilt-image pattern.
18. The data carrier according to claim 1, characterized in that
the laser-sensitive layer and/or the securing layer are covered
with further layers that are transparent at least in the area of
the identifiers, such that at least one of the laser-sensitive
layer or the securing layer are disposed in the interior of the
data carrier.
19. The data carrier according to claim 1, characterized in that
the data carrier constitutes an identification card, such as a
credit card, bank card, cash card, authorization card, identity
card or passport personalization page.
20. The data carrier according to claim 1, characterized in that
the data carrier constitutes a transfer element disposed on a
carrier layer for application to an identification card or the
like.
21. A method for manufacturing a data carrier according to claim 1,
in which the laser-sensitive layer that is opaque in the visible
spectral range is combined in such a way with the securing layer
that is metallized at least in a sub-area that the opaque,
laser-sensitive layer and the securing layer overlap at the
metallized sub-area of the securing layer, and in which, to
introduce the identifiers, the layer structure is impinged on from
the side of the laser-sensitive layer with laser radiation, causing
separate identifiers to each be introduced simultaneously and in
perfect register into the laser-sensitive layer and the metallized
sub-area of the securing layer.
22. The method according to claim 21, characterized in that the
identifiers are introduced with pulsed laser radiation.
23. The method according to claim 21, characterized in that, as the
identifier, a halftone pattern reproduced from an original in a
screening technique is introduced, different brightness levels of
the halftone pattern being produced by a different grid-point
density, a different grid-point size and/or by a different
grid-point blackening, and the grid-point density being selected to
be between 50 and 500 dpi.
24. A method for checking the integrity of a data carrier according
to claim 1, in which the data carrier is illuminated with a strong
light source, the register accuracy of the identifiers in the
opaque, laser-sensitive layer and the metallized sub-area of the
securing layer is determined, and on the basis of the determined
register accuracy, the integrity of the data carrier is assessed.
Description
[0001] The invention relates to a data carrier into which, by means
of a laser beam, identifiers are introduced that are visible in the
form of irreversible changes, caused by the laser beam, in the
optical properties of the data carrier. The present invention
further relates to a method for manufacturing such a data carrier,
as well as a method for checking the integrity of such data
carriers.
[0002] It is known to personalize identification cards, such as
credit cards, bank cards or identity cards, by means of laser
engraving. In personalization by laser engraving, the optical
properties of the card material are irreversibly changed, in the
form of a desired identifier, through suitable guidance of a laser
beam.
[0003] For example, the identification card described in
publication DE 29 07 004 includes two cover sheets and a card
insert in which, through one of the two cover sheets, the
personalization data are inscribed with a laser beam. To impede the
reproduction of such identification cards with modern copiers, the
personalization data are often introduced into metallic layers in
front of a dark background. Since the metallic substrate causes a
specular reflection of incident light beams, and the detector in
copiers is usually disposed such that it can pick up only the
diffusely scattered light from the original, the metallic surfaces
and the introduced data appear all black in the copy.
[0004] Despite the recognized high security level of
laser-personalized identification cards, there is a residual risk
of forgery as a result of a separation of card front and card back
and the resulting possible manipulation of the information located
inside, such as text and image objects. In particular, after a
separation of the card sheets, a metal foil located inside is
counterfeitable or replaceable.
[0005] Based on that, the object of the present invention is to
specify a data carrier of the kind described above having increased
counterfeit security. Furthermore, it should be possible,
preferably also for laypersons, to detect manipulation attempts
with simple means.
[0006] This object is solved by the data carrier having the
features of the main claim. A method for manufacturing such a data
carrier and a method for checking the integrity of such data
carriers are specified in the coordinated claims. Developments of
the present invention are the subject of the dependent claims.
[0007] The data carrier according to the present invention builds
on the state of the art in that it comprises a laser-sensitive
layer that is opaque in the visible spectral range and that is
combined with a securing layer that is metallized at least in a
sub-area. Said identifiers are introduced by the laser beam
simultaneously and in "perfect register" into the laser-sensitive
layer and the metallized sub-area of the securing layer. In this
way, the integrity of the data carrier can be checked at any time
by checking the register accuracy of the identifiers. For this, a
very luminous flashlight or even viewing the data carrier against
daylight is sufficient.
[0008] Advantageously, the introduction of the identifiers into the
securing layer can occur, for example, through material ablation in
the metallized sub-area or through a local transformation of the
metal into a transparent or translucent modification.
[0009] In expedient embodiments, one or more intermediate layers
are disposed between the laser-sensitive layer and the securing
layer. The intermediate layers are preferably transparent and can
also be colored and/or printed on. They can also be furnished with
fluorescent properties. In particular, if the intermediate layers
are not continuously transparent, they advantageously exhibit one
or more apertures in the area of the identifiers to enable the
identifiers to be seen and to use the opaque background as a
contrast element.
[0010] Advantageously, the metallized sub-area can be vapor
deposited on the securing layer or formed by a printing layer of a
metallic effect ink. The metallized sub-area can also exhibit a
diffraction pattern, especially a hologram pattern, such that an
additional angle-dependent image impression is created for the
viewer.
[0011] The laser-sensitive layer is preferably formed by a plastic
foil that is doped at least in a sub-area. In other, likewise
advantageous embodiments, the laser-sensitive layer is formed by a
plastic foil that is provided at least in a sub-area with a
printing layer that absorbs the laser radiation. The plastic foil
can then be transparent, as the opacity required for the contrast
effect is provided by the printing layer. Furthermore, the plastic
foil can be furnished with fluorescent properties, for example by
incorporating fluorescent pigments during manufacturing of the
foil. In both variants, the plastic foil can be composed of, for
example, polycarbonate or polyester. It is also conceivable to use
paper as the laser-sensitive layer. Preferably, paper made of
cotton fibers is used. The laser-sensitive layer can also be a
metal layer. Preferably, the metallized sub-area and the
laser-sensitive layer are then formed of differently colored
metals.
[0012] While only a single laser-sensitive layer that is opaque in
the visible spectral range has been described so far, according to
the present invention, it is also possible to provide multiple such
layers in the data carrier. The various laser-sensitive layers can
then be provided with different types of identifiers or combined
with different metal layers.
[0013] The identifiers introduced into the data carrier can include
any patterns or characters. Identifiers that comprise a halftone
pattern reproduced from an original, especially an image, such as a
portrait, are particularly well suited, as the human eye can
perceive even the smallest discrepancies in congruence there. The
halftone pattern is preferably introduced in screening technique,
different brightness levels of the halftone pattern being produced
especially by a different grid-point density, a different
grid-point size and/or by a different grid-point blackening.
[0014] In an advantageous development of the present invention, the
metallized sub-area, together with the opaque layer, displays, in
impinging light, a tilt effect in which the image impression of the
introduced identifiers switches from a positive image to a negative
image when the viewing angle changes. As explained in detail below,
this contrast reversal is explained by the interplay of the
specularly reflecting metallic sub-areas and the diffusely
scattering identifier areas. This effect can also be used as copy
protection.
[0015] Instead of a single metallized securing layer, multiple such
securing layers can also be provided. For example, a spatial effect
can be achieved by combining metallized securing layers in
different levels. The metallized securing layers can additionally
be provided with a laser tilt image pattern, as described for
example in publication EP 0219 012 A2.
[0016] For protection, the laser-sensitive layer and/or the
securing layer can be covered with further layers that are
transparent at least in the area of the identifiers, such that the
laser-sensitive layer or the securing layer, preferably both
layers, are disposed in the interior of the data carrier.
[0017] The data carrier preferably constitutes an identification
card, such as a credit card, bank card, cash card, authorization
card, identity card or passport personalization page. The data
carrier can also constitute a transfer element disposed on a
carrier layer for application to an identification card or the
like.
[0018] To manufacture a described data carrier, the laser-sensitive
layer that is opaque in the visible spectral range is combined with
the securing layer that is metallized at least in a sub-area and,
where appropriate, with further layers, and, for introducing the
identifiers, the layer structure is impinged on from the side of
the laser-sensitive layer with laser radiation, causing the
identifiers to be introduced simultaneously and in "perfect
register" into the laser-sensitive layer and the metallized
sub-area of the securing layer. The laser beam preferably impinges
vertically on the layer structure. However, any other angle of
incidence of the laser beam on the layer structure is also
conceivable. Thus, if the laser beam is radiated at a certain
angle, e.g. 70.degree., to the card surface, the congruence of the
engraved identifiers in the different levels of the layer structure
is, in principle, preserved. When viewing, the congruence must
then, of course, be checked at the angle at which the identifier
was engraved in the layer structure by means of a laser.
[0019] The identifiers are preferably introduced with pulsed laser
radiation, preferably having a wavelength in the infrared or
visible spectral range. Advantageously, a halftone pattern
reproduced in screening technique from an original is used as an
identifier, different brightness levels of the halftone pattern
being produced especially by a different grid-point density, a
different grid-point size and/or by a different grid-point
blackening. Said grid-point density is expediently selected to be
between 50 and 500 dpi (dots per inch), preferably between 150 and
250 dpi, particularly preferably between 170 and 200 dpi.
[0020] To check the integrity of a data carrier of the kind
described, the data carrier is illuminated with a strong light
source, the register accuracy of the identifiers in the opaque,
laser-sensitive layer and the metallized sub-area of the securing
layer is determined, and on the basis of the determined register
accuracy, the integrity of the data carrier is assessed.
[0021] Overall, the present invention provides a significant
increase in the security of personalized data carriers, and at the
same time, simple verifiability of the protection is given. When
manufacturing cards, for example, three pieces of information for
protecting against forgery can be introduced into the card material
in one work step without substantial impact on the throughput:
[0022] 1) a photo, for example on the front of the card, [0023] 2)
a transmitted light effect that delivers, depending on the kind of
personalization, a positive or negative image, and [0024] 3) a
personalization of a metallized foil layer, opposite and absolutely
congruent to the photo on the front of the card.
[0025] Further exemplary embodiments and advantages of the present
invention are explained below by reference to the drawings. To
improve clarity, a depiction to scale and proportion was dispensed
with in the drawings.
[0026] Shown are:
[0027] FIG. 1 the front view of an identification card according to
an exemplary embodiment of the present invention, diagrammed
schematically,
[0028] FIG. 2 the rear view of the identification card in FIG.
1,
[0029] FIG. 3 a cross section through the identification card in
FIG. 1 along the line III-III,
[0030] FIG. 4 to 7 cross-sectional views of further identification
cards according to exemplary embodiments of the present
invention.
[0031] FIG. 1 and 2 show the front and rear view of an
identification card 10 according to the present invention,
diagrammed schematically. The identification card 10 includes a
portrait 12 of the cardholder, as well as further personal data 14,
in the exemplary embodiment the first and last name of the holder.
Furthermore, the identification card can include further personal
or non-personal data 16, such as birth date, nationality, issuing
authority, issue date and the like. The portrait 12 and the name 14
on the identification card 10 are for illustration purposes only
and do not correspond to any real person.
[0032] While the front 26 of the identification card 10 displays
the portrait of the cardholder as a screened halftone image 12,
from the card back 28, a portion of the portrait is visible in a
metal foil 18. Due to their creation simultaneously and in
substantially accurate register (or "perfect register" as that term
is used in the art), described below, in an intact identification
card 10, the halftone portrait 12 and the portrait inscribed in the
metal foil 18 are disposed completely congruently.
[0033] This congruence can be checked with simple aids, for example
with a strong flashlight or even by viewing the identification card
against daylight. In a manipulation attempt through separation of
the card foils and replacement or forgery of the metal foil 18
located inside, the congruence of the two portraits is destroyed
and can then no longer be reconstructed with the original accuracy.
The personalization of the card front and the metal foil located
inside is thus protected effectively and easily verifiably.
[0034] The layer structure of the identification card 10 and its
manufacture will now be described with reference to the simplified
schematic diagram in FIG. 3. In the simplest case, the
identification card 10 is composed of a core layer 20 that is
opaque in the visible spectral range, and a transparent foil 22 on
which is vapor deposited, in a sub-area, a metal layer 24, for
example an aluminum, copper or gold layer.
[0035] For personalization, the identification card 10 is impinged
on from the card front 26 with pulsed, infrared laser radiation.
For this, the core layer 20 is doped with additives that are
capable of absorbing the infrared laser radiation and effecting a
local blackening 30 of the core layer 20. The additives are, for
example, fillers. It is possible to control the absorption of the
laser light and thus the degree of blackening depending on the kind
of filler and/or the filler content. The pulse energy of the laser
radiation is selected such that it penetrates the core layer 20 and
is absorbed in the metal layer 24. Through the influence of the
laser radiation, the optical properties of the thin metal layer 24
in the captured modification areas 32 are changed locally such that
the portrait inscribed from the front is visible mirror reversed
when viewed from the card back 28. The change of state of the metal
layer 24 can, for example, consist in a partial or complete local
ablation of the metal layer or in a local transformation of the
metal layer into a transparent or translucent modification.
[0036] In the exemplary embodiment, a Nd:YAG laser having a
wavelength of 1.064 .mu.m, a beam diameter of about 60 .mu.m and a
pulse energy of up to 2 J/cm.sup.2 was used to introduce the
identifiers. Other infrared lasers, such as Nd:glass lasers or the
longer-wave CO.sub.2 lasers, are also possible for the
personalization. It is understood that the laser parameters
concretely used in each case, such as beam diameter and pulse
energy, are matched to the number and the thickness of the layers
to be engraved.
[0037] By scanning the image surface of the portrait 12 in a
defined grid and a pulse-to-pulse variation of the laser output
corresponding in each case to the blackening level, a halftone
image like the portrait 12 having a resolution of, for example, 200
dpi can easily be produced.
[0038] Through suitable selection of the background of the metal
layer 24, it is possible to achieve a tilt effect when viewed from
the card back 28. Here, the image impression tilts in reflected
light when the viewing angle changes, independently of the angle of
tilt, from a positive image to a negative image. Without being
bound to a specific explanation, the contrast reversal is explained
by the fact that light incident from the back is specularly
reflected by the unmodified areas of the metal layer 24, while it
scatters diffusely in the ablated or modified areas 32. If the
viewer is located in the solid angle of the specular reflection,
then the metal layer 24 appears brighter to him than the modified
areas 32, while from other viewing angles, the diffusely reflecting
area 32 appears to him to be unchanged in brightness, but the metal
layer areas appear dark. This effect is particularly noticeable
when the metal layer 24 is disposed in front of a light, for
example white or pastel-colored, background.
[0039] FIG. 4 shows a further exemplary embodiment of an inventive
identification card 40 having a more complex layer structure. The
layer sequence of the identification card 40 comprises a
transparent lightly doped foil 42, a transparent undoped foil 44, a
transparent heavily doped foil 46, an opaque foil 48, a transparent
undoped foil 50 and a transparent lightly doped foil 52. In the
exemplary embodiment, all of the cited foils are polycarbonate
foils. If appropriate, the foils are furnished with fluorescent
properties.
[0040] Prior to joining the foils, a metal layer 54, here an
aluminum layer, of several tenths of a .mu.m thickness was vapor
deposited on the transparent undoped foil 50. The foils were then
laminated and the card thus formed, as described above, was
personalized by laser engraving. Thereby, local blackenings 56 were
created in the doped foils 42 and 46 due to the absorption of the
laser radiation. At the same time, due to the laser radiation in
the modification areas 58, the optical properties of the metal
layer 54 were irreversibly changed locally and congruently with the
blackenings 56. Further identifiers can be inscribed in the doped
foil 52 from the back of the identification card 40.
[0041] For the purposes of clear illustration, the exemplary
embodiment in FIG. 5 is shown in an exploded view in which the
individual layers have not yet been joined and in which the
personalization of the identification card 60 has not yet occurred.
The layer structure of the identification card 60 comprises a
transparent lightly doped foil 62, a printed-on transparent foil 64
that can be undoped or lightly doped, a heavily doped transparent
foil 68 that is provided with a thin metal layer 76, a printed-on
heavily doped transparent foil 70 and a lightly doped transparent
foil 74. In this exemplary embodiment, too, the cited foils are
polycarbonate foils. Here, too, the foils can be furnished with
fluorescent properties.
[0042] The foils 64 and 70 are each provided with a printing layer,
66 and 72, the printing layer 72 exhibiting, in the area of the
metal layer 76 or at least in the area of the introduced
identifiers, apertures 80 to enable the identifiers to be seen. In
this exemplary embodiment, the opacity of the card body is
achieved, not through an opaque foil, but rather through the
printing layers 66 and 72 that are opaque at least in sub-areas. In
particular, the printing layer 66 is opaque in the area of the
metal layer 76. The printing layers 66 and/or 72 can also be
applied with effect inks, such as fluorescent inks or inks
containing optically variable pigments.
[0043] In the exemplary embodiment, the metal layer 76 is formed by
a hologram patch having a diffraction pattern 78 that, in a manner
that is known per se, gives the viewer, in addition to the
above-described portrait, an angle-dependent image impression. The
hologram patch can include, for example, an angle-dependent color
play or an image motif that moves or changes when tilted. Such a
hologram patch can, of course, be used in all of the embodiments
described instead of a simple metal layer.
[0044] FIG. 6 shows a further exemplary embodiment of an
identification card according to the present invention. The layer
sequence of the card comprises a transparent foil 90 that was
printed on across its entire surface with a fluorescent imprint 91.
Above that is located a metallic layer, preferably silver or gold
colored 92. This is covered with a transparent foil 93 on which, in
turn, a metallic layer 94 is located that is preferably silver or
gold colored. The metal layers 94 and 92 preferably have a
differently metallic appearance, such that the card, viewed from
the top and the bottom, respectively, exhibits a different
appearance. This card structure is now impinged on from the side of
the layer 94 with laser radiation, such that the marking 100 is
produced in the layers 92 and 94. In this case, the marking is a
metal ablation, such that apertures are created in the metal layer.
By illuminating the card from the side of the layer 90 with UV
radiation, to a viewer viewing the card from the side of the
coating 94, fluorescent patches are perceptible in the area of the
aperture 100. The apertures 100 that appear fluorescent to the
viewer when illuminated appropriately can be pictographic
illustrations as well as codes.
[0045] FIG. 7 shows a further exemplary embodiment according to the
present invention. The layers 95 are metallic layers that were
vapor deposited on a transparent foil 97. The layers 96 are
likewise metallic layers that were vapor deposited on the side
opposite the metallic layer 95. These two layer structures were
each laminated onto one side of a foil 98 doped with a fluorescent
pigment. When this structure is impinged on with laser radiation,
the markings 101 are produced in the metal layer. By removing the
corresponding metal layer on the patches 101, the viewer can again
perceive, given appropriate illumination with exciting radiation,
fluorescent marks on the patches 101.
* * * * *