Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
(44 936 ar A METHOD OF PRODUCING A M~LTIP~E LAYER IDENTIFICATION
CARD, AN APPARATUS FOR PRACTICING SUCH METHOD AND AN
IDENTIFICATION CARD
BACKGROUND OF THE INVENTION
1. FIELD OF THE INVENTION
The present invention relates to a method of
producing a multiple layer identification card. It
also refexs to an apparatus for practicing such method.
The invention relates further to an identification card
produced in accordance with said method.
2. DESCRIPTION OF THE PRIOR ART
Multiple layer identification cards are
generally known, whereby the expression identification
card shall encompass all kinds of such cards such as
identifyin~ cards, credit cards9 cards for checks,
member identifications, passports, certificates, sub
stitutes for msney and further voucher~ and documents
as well.
The use of such identification cards is wide-
spread. The safety principle of such cards is that on
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the one hand the cards carry visible and invisible
safety markings which guarantee on a checkable basis
their origin from a legitimate or authorized, respec-
tively, card issuing place and on the other hand also
features being specific to a person which prove that
the respective carrier of such card is the legal carrier
thereof. Features of the first mentioned kind are
generally fea-tures applied by a printing technique such
as safety identifications, guilloches, watermarks,
etc., while the individualizing features are data re-
ferring to the person, which are invisibly present on
a magnetizable strip or visibly in form of an embossment,
photograph or signature present on the card.
The Swiss patent specification C~-PS 646 536
discloses e.g. a three--layer card, of which the center
layer is opaque and is printed in a state connected to
at least one further layer with individualizing features
by means of a laser beam. Accordinglyr an unauthorized
access to the center layer is difficult. This procedure
in accordance with the CH-PS 646 536 has, however, the
drawback that it allows an achieving of relatively in-
ferior picture qualities, which are of a correspondingly
low value regarding safety features. Because, further-
more, the card is written upon in its finally produced
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state, manipulations of such inscriptions are not
impossible.
SUMMARY OF THE INVENTION
A general object of the present invention is
to provide a method of producing a multiple layer card
as well as to provide such a card in which indi-
vidualizable and genexal safety features are located on
its layers which can be counterfeited with great dif-
ficulties only and which can be distribu-ted in a simple
way among a Flurality of layers in order to secure an
as high as possible safety against a misusing of data
and against counterfeitings during the production and
reproduction thereof.
A further ob~ect is to provide a method of
producing a multiple layer identification card which in-
cludes the steps of taking up information which is
specific to the card owner and to the card safety
feature and of storing such information on a data
carrier; of printing information read by the data carrier
by means of a digital printing method onto at least one
foil section; of placing the at least one foil section
between a translucent cover foil, which is not printed
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or printed by conventional or digital or both methods
with safety specific and/or other information and a
base foll which is not printed or printed by conventional
or digital or both methods and of connecting the at
least foil section inseparably to the two foils; and of
cutting or stamping the identification card in the
desired form out of the composite.
This allows a printing of the individual layers
separably from each other and by various printing
techniques, i.e. on the one hand by a conventional safety
printing and on the other hand by a digital printing.
By means of such digital printing mentioned person or
carrier specific features may be produced as chromatic
or achromatic gray hue pictures which are difficult to
copy. The individual layers which already have been
provided with safety features are interconnected in-
separably not earlier than at the final interconnecting
thereof. A further important advantage of the method
is that the front as well as rear side of the card can
be provided independently of each other with indi-
vidualizing features or data, of which the comparison
serves as safety feature.
Yet a further object of the invention is to pro-
vide a method of producing a multiple layer identifi-
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cation card in which the digital real image printing
is configurated as a dot overlap compensated error dif-
fusion method, by means of which gray hue pictures having
an excellent quality e.g. photograph-like pictures of
the card owner can be generated, which are safe against
a counterfeiting. The evaluation of the compensation of
the digital printing method is preferably adjusted to
the respective printing procedure, the printing and the
printing basis which forms an additional safety element.
According to a preferred embodiment a plurality
of translucent foils is present, which are printed by
means of digital printing methods such as an ink jet
printing method or a digital electro-graphical method
such as e.g. digital laser printing, electro-erosion.
Furthermore, a further person or carrier,
respective specific safety feature which is not
recognizable from the outside may be formed in a plane
of the card as transparent, characteristic and optically
scannable inner structure. To this end e.g. light con-
ductors or other optical elements can be placed into one
or between the individual layers such that a optical
contact for beaming light into such optical elements
through the side edges of the card and for scanning the
light characteristically changed by the inner structure
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is achieved. The optical inner structure represents
a coded information of the card, which can be scanned
by corresponding light contacts.
BRIE.F DESCRIPTION C)F T~3E DRAWINGS
The invention will be better understood and
objects other than those set forth above will become
apparent when consideration is given to the following
detailed description thereof. Such description makes
reference to the annexed drawings, wherein:
Fig. 1 is a schematic illustration of the
layers of the identification card before they are con-
nected to each other;
Fig. 2 is a schematic top view of a laminated
card;
Figs. 3 to 6 illustrate various variants of
the arrangement of light conductors between layers of
the card;
Fig. 7 illustrates schematically a reading
device for a card having embedded light conductors;
Fig. 8 illustrates a further variant of a
reading device to cooperate with light conductors
arranged in loops;
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Fig. 9 is a detailled illustration of this
reading device;
Fig. l0 illustrates a further reading device
with an abutment stop and a card with integrated opti-
cal structure data;
Fig. ll is an illustration of a preferred
embodiment of the embedding of the chip into a layer of
~he card; and
Fig. 12 is a schematic illustration of a
further preferred structure of the card.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
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Fig. l illustrates schematically layers or
foils, respect1vely, of a first embodiment of the iden-
tification card, where the individual foil sections are
illustrated already in the shape of the final card
whereagainst during an actual production of such cards
initially foil sections are present which are larger
than the final shape of the card.
Reference numeral 8 identifies a base foil
having mainly the duty to provide the card with a
sufficient mechanical rigidity. The thickness of this
base foil 8 can also be selected in accordance with the
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field of application of the card, whereby obviously also
the number of further foils must be taken into considera-
tion such ~hat ~he total thickness of the identifica-
tion card remains within limits given by its specific
application. The base foil 8 is made of a plastic
material and can be present in a bipartite condition
having an optical inner structure such as light con-
ductors 24 embedded therein or may be simply a one-
piece structure.
The reference numeral 2 identifies a front
cover foil which consists also of a plastic material
and may be equipped with a UV-filter foil 3 or a layer
which includes materials which absorb UV-rays. At least
one translucent foil 4 is located between the base foil
8 and the front cover foil 2.
~ his translucent foil 4 is equipped with a
digital print such as will be explained in detail
further below. Following this foil 4 further not
particularly illustrated translucent foils may be pro-
vided.
In accordance with the invention the translu-
cent foil 4 and possibly further such foils are printed
by a digital printing method with data which are specific
to the owner or carrier, respectively, of the card and
to safety measures. The expression digital printing
method shall be understood as a printing method in
which pictures and letters are built up by individually
printed points. To this end preferably an ink jet
printer of known design is used. In order to facilitate
the application of the ink onto the foils these foils
consist preferably of a special plastic foil, which
carries a porous coating for receipt of the printing ink.
The sponge-like structured surface of such foil sucks
the printing ink into the porous coating due to a
capillary effect such that a flowing or blurring, re-
spectively, of the ink during the printing step or by
the further treating is avoided because the ink dries
relatively slowly. The production of such porous or
open cell, respectively, surface structures is generally
known in the technical field of plastic material (see
"Kunststofftaschenbuch", 16. edition, Munich 1965,
P. 320 ff). If an ink jet printer is used, which
operates in accordance with the hot melt ink printing
method, it is also possible to use a common not coated
plastic foil. The foils 2, 4 and 8 described up to
now can also be printed by common printing methods
such as a screen printing, offset printing, etc. such
as to print e.g. texts, signatures, shadings, guilloches,
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ornaments etc. Preferably, the common printing method
is used to print patterns on the cards which are the
same for all cards and to produce the card specific
information by means of the digital printing method.
The digital printing method for real pictures
is made in accordance with the dot overlap compensated
error diffusion method. Such method is generally known
and disclosed in a paper by P. Stucki, in "Advances in
Digi~al Image Processing for Document Reproduction,
Lecture Notes in Computer Science", No. 163, pp 256-302,
"VLSI Engineering Beyond Software Engineering", Springer
Publishing House 1984.
This article discloses in detail that the
so-called dot overlap influences the ~uality of a
digital picture, i.e. a picture set together from in-
dividually printed pointsO It centers thereby around
the effect that adjoining, substantially circular points
of a digital picture must overlap each other partly in
case a complete covering by ink shall be achieved. This
overlapping thus, however, falsifies the picture because
there every adjoining point does no longer supply its
complete color density contribution to the picture. In
order to corxect the nonlinearity of the ink covering
of the picture ensuing from such effect the dot over-
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lap is analytically or mathematically, respectively,
taken into account and corrected in case of the digital
printing. Thus r such a digital, person specific printing
can be achieved in connection with the present invention,
which due to the high quality of the picture is very
difficult to counterfeit. It is, for instance, possible
to print the photographic picture of the card owner
such onto one of the foils that it achieves the quality
of a real photographic picture without, however, to
incorporate its safety related drawbacks ~see hereto
Fig. 2).
An additional safety effect is also arrived at
due to the fact that the compensation of the dot overlap
depends on the respective size and shape of the dots
produced during the printing and this again from the
printer used and from.the kind of the substrate re-
ceiving the print. Accordingly, the corresponding
coefficients for the compensation are interrelated with
the respective prir.ter being used and the respective
foil being used. Due to this fact the suitable coef-
ficients are stored in the printer control unit in a
removable and exchangeable ROM-memory. This ROM-memory
acts as additional safety element because without the
suitable ROM-memory no sufficient digital printing
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quality can be arrived at due to an erroneous compensa-
tion of the dot overlap.
The card illustrated in Fig. 1 has at its
reverse side also at least one translucent, digitally
printed foil 5 followed towards the outside by a re-
verse cover foil 6 having a U~~filter 70 Due to this
structure it is possible to independently print the card
digitally at its front side and its back side, whereby
correlatio~s between the individual information on
the front and on the rear side may be applied as safety
feature. Mentioned UV-filters 3, 7 are used in order
to protect printing ink which fades when exposed to
light such as ink from an ink jet printer. To this end
a correspondingly coated foil or a foil which incor-
porates UV-absorbin~ materials can be used.
Furthermore, a magnet recording track can be
applied at the rear side of the card.
It already has been mentioned that the base
foil 8 may in turn be made as a composite and can be
provided with a transparent inner structure which is
characteristic for the specific card and may be optically
scanned. Such an inner structure can be applied specifl-
cally by embedding a plurality of light conductors. These
light conductors 24 are arranged such that their face
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surfaces are located flush at the edge of the foil 8
such as will be described in detail further below.
Fig. 2 illustrates schematically a top view
of this identification card. The base foil 8 which is
translucent perpendicularly to the plane of the card
is thereby printed by the text 11 and the texture 12 in
a conventional manner and which are identical for all
cards. The address 13 of the owner of the card, a bar
code 14 and a fingerprint 15 of the card owner are
printed e.g. by means of an ink jet printer onto the
translucent foil 4. Possibly, furthermore, the photo-
graph 16 and the signature 17 of the card owner can also
be printed digitally on the card as well as the number
18 of the card. A e.g. digital printing of the rear
translucent foil 5 may be visible from the rear side of
the card. Specifically it is also possible to locate
an area for the manual signature of the card owner on
the rear side such that it can be compared with the
signature printed onto the front side of the card.
The digitally printed person specific informa-
tions 13, 15, 16, 17 are recorded during the taking up
of the data by aid of a keyboard, a scanner, a video
camera or another sensor in a digltal manner and stored
digitally. During the production of the card the data
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processing and the printing for the foils 4, 5 and 8
may be separated completely from each other. The pro-
cedure here is preferably such that an information fore-
seen for one foil alone does not allow a misuse. The
various layers are brought together not earlier than
for an interconnecting of same and are then treated
further together.
The interconnecting of the foils and the
further finishing treatments such as punching, cutting
out, polishing their edges etc. is made in accordance
with common techniques such as e.g. by laminating.
It is, howeverj also possible to achieve an adhering
by means of a resin or a lacquer.
Where the hitherto mentioned digital and con-
ventional printing methods form basically visible safety
features, the inventive card allows an integrating
thereinto of additional not visible person specific
identification features. As has already been mentioned,
light conductors 24 or other optically scannable struc-
tures may be built into a layer 8 to achieve such. Due
to the face surfaces formed at the edges of the cards
a scanning of the optical information proceeding by a
making or breaking of light beams can be made by cor-
responding reading apparatuses. By means of such the
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optical information which is integrated in the card
and as such is not visible can be machine-read.
In the Figs. 3 to 6 various light conductor
arrangements representing optical information carriers
are illustrated exemplary. Fig. 3 illustrates additional-
ly how the corresponding layer 8 of the card is produced.
First of all, a linear arrangement of the
light conductors 24 is illustrated in Figs. 3 and 4.
In the arrangement in accordance with Fig. 3 the person
specific coding is produced during the production by
means of a severing of individual light conductors 24'
by means of a mechanical cutting or a destroying by
means of a laser beam such as indicated by the arrow 26
The hole 25 which then is generated in the layer 8 is
re-covered during the laminating by the other foils
such that the entire structure is not visible from the
outside. According to Fig. 4 the code is achieved by
a selective arranging of the light conductors 24. At
selected raster-like arranged areas 24 there is no
light conductor 24 or no light contact, respectively,
which i5 recognizable by the reading apparatus.
Fig. 5 illustrates an embodiment which
cooperates with a reading apparatus or reading unit,
respectively, which will be explained in detail with
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reference to Figs. 8 and 9. Here one or a plurality
of light conductors 24 are arranged in a loop-like
manner such that the infeed and the detecting or
scanning, respectively/ of the light occurs at one edge
28 only of the card. The coding is made by a selecting
of the distance between the two ends of the light con-
ductor at the edge 28.
Finally, Fig. 6 illustrates a combination of
both modifications.
Suitable structures for the light conductors
are light conducting ylass fibers having a thickness of
e.g. 0.23 mm or 0.46 mm. Because these are partly
pressed into the card foils during~the laminating pro-
cedure the final~card remains completely planar at
its surfaces. Also visua~ly the embedded fibers cannot
be recognized specifically when viewing the-card from
the top.
For forming the layer 8 which in itself is
set together as a combination of two foils 8', 8" the
light conductors 24 are arranged as described above on
one of the two foils 8'. This can be made e.g. by a
controlled positioning apparatus which feeds the light
conductors from a roll, positions these light conductors
and fixes the conductors by means of a local melting of
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of the foil 8' or adhesive areas (see areas 30 in
Fig. 5). Thereafter the foils 8', 8" are combined.
The positioning of the light conductors ean
thereby be made within the limits of eonditions still
to be mentioned further below by all means
stochastically as long as the struetures arrived at
allow an individual associating of the corresponding
(random) information and accordingly of the eard to a
given owner. In this case the positioning apparatus
may be controlled hy a random generating unit. An
absolutely random arranging of the light conductors 24
is also possible in ease of the seanning units having a
eorresponding design. The arrangement of the light eon
duetors forms in this ease a kind of random "fingerprint"
of the eard, whieh ean be ehecked by means of the
seanning unit or apparatus, respeetively.
Figs. 7, 8 and 9 illustrate sehematically how
the light conduetors embedded in the layer 8 as addi-
tional safety fea~ure ean be evaluated optieally. The
one side of the eard 21, at whieh the light eonduetors
24 open, is illuminated by a light source 22 in a
sehematieally only illustrated reading or seanning,
respeetively, apparatus 20 in accordance with Figs. 7,
8. Light sensitive elements 23 of this reading unit
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check then at the opposite edge of the card, at which
the other ends of the light conductors end, if and at
which points the light has been correctly conducted
through the card, i.e. if a light contact is present.
Obviously, configurations are also possible, according
to which the light source 22 can be located at the same
side of the card, if the light conductor or licht con-
ductors, respectively, have been arranged accordingly.
A corresponding reading unit follows specifi-
cally out of Figs. 8 and 9. Here the light conductors
24 are arranged in a loop-like fashion such that both
respective ends of a light conductor can be illuminated
optically and scanned at the same edge of $he card.
Flg. 9 discloses speclfically which number
of possibilities of variations of the inner structure
data can be achieved. A card is schematically illus-
trated which has a number M (in the example 4) loop-
shaped arranged light conductors 24. The reading unit
20 has a number N (in the example 32) light sensitive
elements 23, e.g. a linearly arranged CCD-array, which
extends over a length L. Furthermore, a light source
22 is arranged at the reading unit 20 at a distance D
from the first of the light sensitive elements 23.
The light conductors 24 in the card can now be
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arranged as such arbitrarily under the single condition
that the two ends of light conductor are not closer than
a distance D and not more distant than the distance L+D
at the points where they end open at the side edge
of the card.
If now the card is pulled along the reading
unit 20 automatically or by hand and in the direction
of the arrow, every light conductor makes subsequently
a light contact between the light source 22 and one of
the light sensitive elements 23. Every one of the M-
light conductors 24 excites accordingly during the
reading one respective of the N CCD-elements. Ac-
cording to this arrangement substantially NM different
signal sequences are arrived at, of which each single
one is characteristic for one given card. If, for
instance~ M = 4 and N = 32 is chosen, such leads to
substantially 324 = 1'048'576 various signal sequences.
If the distance D is selected differently in
the reading units, different signal sequences for a
given card are arrived at for the various different
distances D such that the possibilities of variations
increase still further. By means of such it is possible
to specifically achieve a selective access allowance
via certain scanning or reading, respectively, units in
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that the access allowability is excluded for certain
cards or corresponding signal sequences, respectively.
The detecting or recording, respectively, of
the signal sequences proceeds via a scanner 40, which
scans the CCD-elements 23 in a high frequency. The
scanned signals are led to a signal processing circuit
41, which derives thereout the inner structure data
assigned to such respective card and provides such via
a data bus 42 to a (not illustrated) calculator. These
inner structure data of the card are preferably coupled
to other data which are stored on the card by means
of magnitizable strips 39 (see Fig. 12) or by a different
procedure. This coupling can be checked in the calcula-
tor. If it is discovered that the coupling is not
correct, such gives an indication that the card has
been manipulated.
In the above described examplè only the
respective distance between the ends of the light con-
ductors 24 are evaluated, but not their absolute position
in the card. Accordingly, it can be declared as a rela-
tive method which has tha advantage that the tolerances
of the arrangements of the cards have no negative in-
fluence. The scanning unit and the card can~ however,
be designed also such that the absolute position of
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the inner optical structure is scanned and evaluated.
Such is the case in a reading unit having an abutment
stop such as schematically illustrated in Fig. 10.
In this case rather than having the light
conductors, which can be arranged in accordance with
the above description, other optical elements 43 are
integrated in a light translucent layer of ~he card.
Such can be e~g. reflecting particles, which are ran-
domly distributed in the card and form a reflecting zone.
By means of a light source 22 light is beamed into the
transparent layer of the card which abuts an abutment
stop 44 of the reading unit. The light reflected by
the edge of the~card is scanned by means of a CCD-array
23 as intensity distribution I. This intensity
dlstribution forms sort of a "fingerprint" which is
characteristic for each single card. A structure
data signal is derived thereof in the above earlier
mentioned signal processing circuit 41, which signal
can be coupled with other card specific data and can
be used in this way as safety feature.
Although the design of the Layer having inte- -
grated optical structure data, specifically including
light conductors, is described herein in connection with
a certain card design having a digital printing and is
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accordingly advantageously useable~ it shall be specifi-
cally noted that light conductors of this design can
also be integrated in other types of cards, specifically
in the commonly known plastic cards. To this end a
filing of a divisional application is distinctly re-
served.
In connection with the above described inven-
tion the arranging of light conductors has the advantage
that aside of the person specific visible features
which are distributed over a plurality of layers addi-
tionally (person specific or different) invisible,
fixedly integrated features can be added in a separate
layer. The information contained fixedly ~herein can
be coupled to other information present on the card
which increases the safety against counterfeiting con-
siderably.
A further embodiment of the invention will
now be described with reference to Figs. 11 and 12, in
which embodiment an electronic circuit formed as chip
30 is integrated in the card. The translucent foil
34 supporting the chip is provided with an embossment
32 corresponding to the size of the chip, in which
embossment the chip is embedded. Thereafter a covering
foil 2 can be mounted over the chip supporting foil 34.
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In comparison with the earlier merely bonding of a
chip between two foils by means of a bonding agent the
chip 30 is better protected against intrusions and
it is possible to produce a planar card~ The foil 34
supporting the chip can be connected specifically at
the end to the other layer.
In Fig. 12 a schematic structure of a card
having such a chip-card is illustrated. The following
foils or layers, respectively, are present proceeding
from the top to the bottom. The cover foil 2 supports
the connections for the chip 30 and can be equipped with
a UV-filter foil or layer. It is followed by the
translucent (transparent) foil 34 supporting the chip
as well as by one or two translucent foils 4 which are
individualized by means of a digital print. Light con-
ductors 24 acting as person specific safety feature
are located in the base foil 8 in accordance with above
described procedure. It is followed again by one or two
foils 5 which are individuali2ed by rear surface infor-
mation applied by means of a digital printing as well as
by a rear cover foil 6 acting as protective layer in-
cluding or without a UV-filter, onto which a magnetic
tape 39 is bonded. Such as is the case ~n the initial-
ly explained embodiment, the foils are provided also here
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singly in the described procedure with person specific
safety features, which accordingly are distributed among
several layers and connected thereafter to each other.
The card produced in accordance with the in-
vention incorporates in comparison with known cards a
largely increased safety against counterfeiting or
forgery due to the several individualizing features
located on independently from each other produced foils
but still having a relation among each other. Further-
more, various techniques can be combined such as con-
ventional safety printing, digital printing, arranging
of light conductors which makes a forgery unthinkable
because it is possible to proceed along separate lines
within the organization of the production of the card,
which lines are led together not earlier than at the
end of the production.
While there are shown and described present
preferred embodiments of the invention, it is to be
distinctly understood that the invention is not limited
thereto, but may be otherwise variously embodied and
practiced within the scope of the following claims.
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