USE OF AND METHOD FOR TESTING OF DOCUMENTS WITH DIFFRACTION-OPTICALLY EFFECTIVE SAFETY LAYERS

UTILISATION ET PROCEDE POUR LE CONTROLE DE DOCUMENTS A COUCHES DE SECURITE DIFFRINGENTES

English Abstract

The invention relates to an application and a method for checking documents.
Hitherto, documents with optical diffraction security layers, specially
holograms, were checked by costly optical monitoring technology. The entire
monitoring process was so time-consuming that the monitoring process could not
be applied to fast operating processing machines. Rapid monitoring (as an
authentication characteristic) constitutes a further security step in
evaluating effective optical diffraction security layers. The effective
optical diffraction layer has a discontinuous metallizing layer and/or
partially metal layers and/or areas of metal layers on various planes. Several
methods of measurement exist to detect electrical conductivity. In practice,
the contactless capacitive method of measurement has proven to be more
practical.

French Abstract

L'invention concerne une utilisation et un procédé pour le contrôle de documents. Jusqu'à présent, des documents à couches de sécurité diffringentes, en particulier des hologrammes, étaient vérifiés en recourant à une technique de contrôle optique coûteuse. Toutefois, l'ensemble du processus de contrôle était d'une durée si longue qu'un tel procédé ne pouvait trouver d'application dans des machines de traitement à grande vitesse. Une possibilité de contrôle rapide représente, en tant que réelle caractéristique, une autre étape de sécurité lors de l'évaluation des couches diffringentes. La couche diffringente présente, dans des plans différents, une couche métallisée discontinue et/ou des couches partiellement métalliques et/ou des zones de couches métalliques. On connaît divers procédés de mesure faisant intervenir une conductivité électrique. Dans la pratique, le procédé de mesure capacitif, sans contact, s'est révélé comme étant d'une meilleure faisabilité.

Claims

6
We claim:
1. Use of the method for the testing of documents using the capacitive
coupling between
transmitter and receiver and the transfer of energy between transmitter and
receiver by electrically conductive safety materials wherein
for the forge test of documents with diffraction-optically effective safety
layers
with a discontinuous metallization layer (14) or partially metallic layers
(12, 20) or
zones of metallic layers in different planes the electrical conductivity is
determined and evaluated.
2. The use of the method as claimed in claim 1 in which
for the forge test of documents with diffraction-optically effective safety
layers
with a discontinuous metallization layer (14) and partially metallic layers
(12, 20)
the electrical conductivity is determined and evaluated.
3. The use of the method as claimed in claim 1 in which
for the forge test of documents with diffraction-optically effective safety
layers
with a discontinuous metallization layer (14) and zones of metallic layers in
different planes the electrical conductivity is determined and evaluated.
4. The use of the method as claimed in claim 1 in which
for the forge test of documents with diffraction-optically effective safety
layers
with partially metallic layers (12, 20) and zones of metallic layers in
different
planes the electrical conductivity is determined and evaluated.

7
5. The use of the method as claimed in claim 1 in which
for the forge test of documents with diffraction-optically effective safety
layers
with a discontinuous metallization layer (14) and partially metallic Payers
(12, 20)
and zones of metallic layers in different planes the electrical conductivity
is
determined and evaluated.
6. The use of the method as claimed in one or several of claims 1 to 5
including
the testing of additionally applicable authenticity features within
demetallized
segments within discontinuous metallization layers (14) and/or partially
metallic
layers (12, 20) and/or between zones of metallic layers in different planes.
7. The use of the method as claimed in claim 6 including
the testing of the fluorescent properties of the additionally applicable
authenticity
feature.
8. The use of the method as claimed in claim 6 including
the testing of the phosphorescent properties of the additionally applicable
authenticity feature.
9. The use of the method as claimed in claim 6 including
the testing of the light-absorbing properties of the additionally applicable
authenticity feature.
10. The use of the method as claimed in claim 6 including
the testing of the magnetic properties differing from the surroundings of the
additionally applicable authenticity feature.
11. The use of the method as claimed in one or several of the preceding claims
in which

8
12, The use of the method as claimed in one or several of the preceding claims
including
the testing of holograms in high-speed processing machines with a speed of up
to 2000 documents per minute,
13. The use of the method as claimed in one or several of the preceding claims
including
the testing of holograms in manual units.
14. A method for testing of documents using the capacitive coupling between
transmitter
and receiver and the transfer of energy between transmitter and receiver by
electrically conductive safety materials in which
a document to be tested which has a diffraction-optically effective safety
layer
with a discontinuous metallization layer (14) and/or partially metallic layers
(12,
20) and/or zones of metallic layers in different planes is guided in such a
way
that it passes through an electronic sensor system at a defined speed,
energy is capacitively transferred from one or several transmitting electrodes
to
one or several receiving electrodes via metallization layers,
the signals available at the receiving electrode or electrodes are amplified
by
means of an electronic evaluation system and are compared with a reference
signal
and a signal classifying the document is available for further processing at
the
output of the electronic evaluation system.
15. The method as claimed in claim 14 in which
a document with diffraction-optically effective safety layers is tested in at
least
two different test directions.

9
16. The method as claimed in claim 14 in which
by means of the electronic evaluation system the classifying signal is
logically
combined with an authenticity signal of an additionally applicable
authenticity
feature after it has been tested by means of another sensor
and a combination signal classifying the document is available at the output
of
the electronic evaluation system for further processing.

Description

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~~~tT TRANSLATION
USE OF AND METMOD FOR TESTING OF DQCUMENTS WITH DIFFRACTION-
OPTICALLY EFFECTIVE SAFETY LAYERS
This invention relates to a use of and a method for testing of documents.
ro date, documents with diffraction-optically effective safety layers, in
particular
holograms, have been tested with costly optical testing equipment. In these
procedures,
the test object has to be positioned very exactly. The entire testing process
takes so
long that these test procedures cannot be used in. high-speed processing
machines.
Testing of, for example, banknotes with a hologram authenticity feature in a
banknote
counting. machine is impossible, as it runs at high speeds between 500 and
7500
banknotes per minute and above. A method and device of forge testing
holographically
protected identity cards is disclosed in Di= 27 47 156. The hologram is
reproduced and a
visual check is carried out. This method is not suited to high-speed,
efficient, person-
independent testing. A device for generating scanning patterns which are
tested by
means of laser, mirror and lens system as well as a photodetector is described
in EP 0
042 946. The economic expenditure is also in this case very high. It would
increase
further if the test objects are to be tested without prior sorting, To avoid
presorting, the
forge test system would have to be arranged several times_
It is the object of the invention to eliminate the disadvantages of the prior
art and to
propose a use, and a method of testing, of documents with diffraction-
optically effective
safety layers, in particular holograms, which can be tested rapidly,
person~independently
and inexpensively. The device is intended for use in document testing devices
and
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z
money processing machines as well as manual test units for testing documents
with
diffraction-optically effective safety layers.
This problem is solved by the futures given in the characterizing clause of
claim 1.
Holograms and other diffraction-optically effective safety layers for the
protection of
certificates and other securities as well as banknotes against forging are now
used more
and more widely- Rapid testability is another safety stage in the valuation of
diffraction-
optically effective safety layers as a fEature of authenticity. Diffraction-
optically effective
layers are composed of a metallized layer, among other things. This
metallization IayEr
is electrically conductive. The electrical conductivity changes with the
thickness of the
layer. The diffraction-optically effective layer has a discontinuous
metallization layer
andlor partially metallic layers andlor zones of metallic layers in different
planes. Various
measuring methods to determine an electrical conductivity are known. In
practice, the
non-contacting, capacitive measuring method has proved useful. This method of
testing
safety documents utilizes the capacitive coupling between transmitter and
receiver and
....
the transfer of energy between transmitter and receiver by bridging an
electromagnetic
field by electrically conductive safety materials. A downstream electronic
evaluatibn
system compares the signal picture of the test object with relevant reference
signals.
The comparison provides a classifying signal for reprocessing. Therefore, a
document
detected as a forgery, for example, could be sorted out by stopping the test
device. The
signal picture depends on the structure of the metallized layer of the
diffraction-optically
effective layer. If the diffraction-optically effective layers have a
discontinuous
metallization layer, several segments of the metallization layer have
different electrical
conductivities. Practice has shown that these different conductivities have an
effect on
the signal picture.
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The testing reliablity is fiurther increased by combining the electrical
conductivity test with
other authenticity features of the diffration-optically effective layer. The
application of
additional authenticity features into demetallized segments within
discontinuous
metallization layers andlor partially metallic layers andlor between zones of
metallic
layers in different planes allows the simultaneous testing of these features
with the
electrical conductivity. L3y means of the electronic evaluation system, an
authenticity
signal of another sensor for the authenticity determination is logically
camf~ined with the
,.,, sensor for measuring the electrical conductivity. At the output of the
electronic
evaluation system, a signs! classifying the diffraction-optically effective
layer is available
for reprocessing. This additional authenticity feature has fluorescent,
phosphorescent or
light-absorbing properties or differs from its surroundings by different
magnetic
properties. Therefore, an optical or magnetic sensor is used. To reduce
detecting and
measuring errors, a sensor carrier is used preferably. This sensor carrier
accommodates
all sensors required for the detection of authenticity features, This allows
the distances
between the sensors to be minimized and the sensors always to be arranged in
defined
positions. To avoid interference effects, the sensor carrier is firmly
connected to the
mounting plato holding the electronic evaluation system. The entire test
device is
arranged within the processing machine so that no additional Expenditure for
the
transport of the test objects is required.
The features of the invention will appear from the description and drawings in
addition to
the claims, the individual features as individual or several things in the
form of
subcombinations representing advantageous, patentable embodiments for which
protection is claimed here. The invention wilt now be explained in greater
detail with
reference to an embodiment thereof which is represented in the accompanying
drawings, wherein
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Fica. 1 is a schematic section through a processing machine with test device
Fig. 2a is a schematic section through a hologram with demetallized segments
Fig_ 2b is a voltage-time diagram of the evaluation signal
Fig. 3a is a schematic section through a hologram with discontinuous
metallization layer
Fig. 3b is a voltage-time diagram of the evaluation signal
Fic~. 4a is a schematic section through a hologram with UV authenticity
feature
~-.. Fig. ~!b is a voltage-time diagram of the evaluation signs! of the
electrical
conductivity test
Fig. 4c is a voltage~time diagram of the evaluation signal of the UV sensor
The testing method according to the invention provides that appropriate
sensors are
installed in suitable positions of banknote counting machines. The sensors for
the
detection of electrical conductivity are designed in such a way that the
sensor can test
the banknote independently of the position of the banknote. Optical or
mechanical
sensors detect the presence of a banknote and provide a reference signal for
the timing
of the test dovice 4_ Simultaneously, the sensors for the forge test of the
hologram are
-.
' activated. Recording the entire time window from the beginning of the
banknote to its
end allows the position of the hologram of the banknote to he determined.
It is shown in Fig. 1 how the test device ~ is arranged on the path of
banknote transport.
The banknote counting machine comprises a feed wheel 1, transport wheels 2, a
banknote guiding device 3 and a test device 4.
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Fig. 2a shows a schematic section through a hologram with a carrying layer 11
and a
partially metallic layer 12. The partially metallic layer 12 comprises several
demetallized
segments 93. Fig. 2b shows the relevant evaluation signal in a voltage-time
diagram.
Fig. 3a shows a schematic section through a hologram with a carrying layer 91
and a
discontinuous metallization layer 14. The discontinuous metallization layer 14
comprises
segments 15, 16, 17, 18, 19 with different electrical conductivity.
Fig. 3b shows the relevant evaluation signal in a voltage-time diagram.
Fig. 4a shows a schematic section through a hologram with a carrying layer '!
1 and a
discontinuous metallization layer 20. The discontinuous metallization layer 20
comprises
demetallized segments 21 as well as additional authenticity features. These
authenticity
features are fluorescent paints 22 which are excited in the test by means of
UV light and
are detected by means of photosensors. Preferably, the additional authenticity
features
are located within the demetallized segments 21. Fig. 4 b shows the relevant
evaluation
signal of the capacitively working sensor testing the electrical conductivity
in a voltage-
time diagram. Fig. 4 c shows the response of the evaluation signal of the
photosensor in
......
a voltage-time diagram.
In the present invention, the testing of documents with diffraction-optically
effective
safety layers was explained with reference to an embodiment thereof. It is to
be
understood, however, that the present invention is not limited to the details
of the
description in the embodiment, as alterations and modifications are claimed
within the
scope of the patent claims.
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Representative Drawing