WO1999009527A1 - Constituting security elements with optical diffraction effect, and device for controlling such elements - Google Patents

Abstract

The invention concerns the constitution of security elements with optical diffraction effect, and a device for controlling such elements. The use of holograms and other security elements with optical diffraction effect for protecting documents and other valuable papers, as well as bank notes against forgery is becoming more and more frequent presently. The element with optical diffraction effect comprises a discontinuous metal coating and/or partial metal coats and/or metal coat zones in different planes, representing an electric data coding, corresponding to the objective. The device comprises a scanner with capacitive functioning. Said scanner consists of a plurality of emitting electrodes placed side by side and a receiving electrode extending parallel to said emitting electrodes arrangement.

Description

Structure of diffractive optical security elements and device for testing such elements

The invention relates to the construction of diffractive optical security elements

and a device for testing such elements.

So far, documents with diffractive optical security elements,

especially holograms, checked with complex optical testing technology. It must

the test object can be positioned very precisely. The entire test process takes so long that these test methods are not used in high-speed processing machines.

A test, for example, of documents with so-called OVD's optical variable device is

not possible within a document processing machine, since these with high

Speeds works. DE 27 47 156 describes a method and a testing device for checking the authenticity of holographically secured identity cards. The OVD is reproduced

and carried out a visual inspection. For a fast, efficient, person-independent

This method is not suitable for testing. EP 0 042 946 describes a device for

Generation of scanning patterns described, which are checked using a laser, mirror and lens system and a photodetector. The economic effort is also in this

Case very high. It would increase even further if the test material was to be checked unsorted. In order to avoid pre-sorting, a multiple arrangement of the

Authenticity checking system necessary. Demetallizations are also known in

Diffractive optical security elements to achieve optical effects, which have so far only been checked using optical methods. The object of the invention is to eliminate the disadvantages of the prior art and a

Development of diffractive optical security elements, especially OVD's, holograms

or kinegrams to propose that quickly, regardless of person and with little

Effort to be checked. Furthermore, it is an object of the invention to provide a device for

Propose review of documents that contain such security elements. The

The device is said to be used both in document processing machines and in manual testing devices

for checking documents with security elements effective in diffraction optics

Find application.

This task is solved by the following description of the invention.

The use of holograms and other diffractive optics

Security elements for securing documents and other securities as well

Banknotes against counterfeiting are currently becoming increasingly common. such

Documents are e.g. the DM banknotes of the 1997 edition, which in addition to the electrical

conductive security strips in the form of a diffractive optical security element

own a kinegram. A quick testability provides a further security level at

Assess the diffractive optically effective elements as authenticity.

Diffractive optically effective elements consist among other things of a metallized layer.

This metallization layer is electrically conductive. According to the layer thickness changes

the electrical conductivity. The diffractive optically active element has according to the invention

a discontinuous metallization layer and / or partially metallic layers

and / or zones of metallic layers in different levels, one

Represent targeted electrical coding of information. The form of coding resembles geometric figures, in particular lines, grid lines, and arcs

Circles that are both regular and irregular. Partially

metallic layer, which is arranged above a carrier layer, contains several

demetallized segments. A discontinuous metallization layer contains segments

with different electrical conductivity.

The device has a capacitive scanner. This scanner consists of

a multiplicity of adjacent transmission electrodes and one parallel to this

Series of receiving electrodes. The scanner is in one

Document processing machine arranged so that the usual

Document processing machines existing optical or mechanical sensors

Activate the test device according to the invention. To reduce detection and

A sensor carrier is preferably used for measurement errors. This sensor carrier takes them all

Sensors for testing on. The distances between the sensors are minimized and the

Sensors always arranged in a defined position. The control of the individual

Transmitting electrodes with electrical energy are delayed by means of control electronics

with a switching frequency in the kHz range. The control electronics contains as

The main components in addition to the power supply are a multiplexer and an oscillator

Provision of the energy for the transmitter electrodes and an oscillator for controlling the

Multiplexers.

In the case of electrical conductivity, the energy of the respective controlled transmission electrode becomes

capacitively coupled over between this transmitting and the receiving electrode. Is not electrical

conductive feature exists, there is no energy transfer between the controlled Transmitting electrode and the receiving electrode instead. The waveform at the receiving electro

is converted into a corresponding signal image. The signal pattern depends on the

Structure of the metallized layer of the diffractive optical element. Assign the

diffractive elements have a discontinuous metallization layer, so

have several segments of the metallization layer different electrical

Conductivities. An electronic evaluation system following the receiving electrode compares this

Signal image of the device under test with corresponding reference signals. The evaluation electronics

consists essentially of a power supply, an amplifier, a demodulator,

a comparator, a microprocessor with memory and filters to suppress

Foreign and interference signals.

In addition to the software for the microprocessor, there are reference signal images in a memory

stored, which are compared with the scanned signal image of the test document. There

the scanner goes beyond the entire width of the document, each becomes electrically conductive

Feature detected with the inventive device. The comparison with the

Reference signal images provide a classifying signal for further processing.

Accordingly, a document recognized as a false certificate could be sorted out, for example

by stopping the test equipment. To reduce interference, the

Sensor carrier compactly connected to a circuit board, which the control and

Evaluation electronics carries.

The entire test facility is located within document processing machines,

so that the space requirement is kept relatively small. The transmit and receive electrodes

become above or below the documents in document processing machines

arranged that a safe scanning is guaranteed. This is done, for example, with the help of Belts or in the area of deflection devices, so that the document during transport

the transmitting and receiving electrodes is pressed.

In a modification of the electrode arrangement, an elongated one is within the scope of the invention

Transmitting electrode parallel to a series of a large number of adjacent

Arrange receiving electrodes. In this case, the received signals are by means of

Multiplexer processed. The other evaluation electronics correspond to those already described.

A further embodiment of the transmitting and receiving electrodes is characterized in that

that a plurality of transmitting and receiving electrodes side by side and / or in series

are arranged. Both the control and the reception of the signals are after the

Multiplex or demultiplexing processes.

For use in handheld devices, they contain corresponding devices for analog

Transport of the document or scanner, the function of which in the transport devices

Copiers, optical image scanners or fax machines are similar.

In a modification to this, a device is provided which by means of stop elements

Position of capacitively operating scanner according to the test device according to the invention

Document defined. In this case, the document is only in the area of broadcast and

Receiving electrodes checked.

The features of the invention go beyond the claims also from the description and

the drawings, the individual features each individually or to

several advantageous protective versions in the form of sub-combinations

represent, for which protection is claimed here. Embodiments of the invention are in

the drawings and are shown in the following examples

explained. show calibrations:

Fig. 1 shows a schematic representation of a document with OVD

meandering demetallized layers,

Fig. 2 shows a schematic representation of a document with OVD

strip-shaped demetallized layers,

Fig. 3 shows a schematic representation of a document with OVD

strip-shaped demetallized layers,

Fig. 4 shows a schematic representation of a document with OVD

latticed demetallized layers,

Fig. 5 shows a schematic representation of a document with OVD

several security elements,

6 block diagram of a test device,

Fig. 7 schematic representation of the scanner with a variety of transmit and

a receiving electrode,

Fig. 8 is a schematic representation of the scanner with a transmit and a

Variety of receiving electrodes,

Fig. 9 schematic representation of the scanner with a variety of transmit and

Receiving electrodes,

Fig. 10 schematic representation of the scanner and one to be tested

Side view of the document,

11 shows a schematic section through an OVD with demetalized segments

Fig. 12 voltage-time diagram of the evaluation signal Fig. 13 schematic section through an OVD with discontinulicner

Metallization layer

Fig. 14 voltage-time diagram of the evaluation signal

The examples shown in FIGS. 1 to 5 each show documents

Security elements according to the invention, the capacitively operating scanner

device according to the invention is also shown schematically.

1 shows the schematic structure of an OVD 1 with a metallization layer 2

shown. The metallization layer 2 has a demetallized zone 3. In top view

the demetallized zone 3 has the shape of a meander. The width of the demetallized

Zone 3 in the form of a meander is larger than the smallest distance between two electrodes.

The capacitive scanner consists of a large number of adjacent ones

Transmitting electrodes 5 and a parallel to this series

Receive electrode 6.

Fig. 2 shows the schematic structure of an OVD, in which alternately metallized

strip-shaped zones 7 and demetallised strip-shaped zones 8 parallel to one another

are arranged. The zones 7, 8 which are strip-shaped in plan view run parallel or

perpendicular to the document transport direction. The latter case is shown in Fig. 3. The

The distance between two zones of the same electrical conductivity is between 0.2 and

1.0 mm. The widths of the zones with the same electrical conductivity vary.

A combination of the features of Examples 2 and 3 is shown in FIG. 4. Parallel to

Document transport direction are alternately metallized strip-shaped zones 7 and

demetallized strip-shaped zones arranged. The metallized zones 7 are by a

Strip-shaped demetalized zone 9 running perpendicular to it is interrupted. 5 shows a document with several OVD's. The targeted combination

Diffractive optical security elements result in a further coding. This will

test reliability increased.

6 to 9 represent the block diagram and various configurations of the

capacitive scanner 4.

6 shows the block diagram of a test device according to the invention, consisting of a

Control electronics, a capacitive scanner 4 and evaluation electronics. The

Control electronics essentially contain one in addition to the power supply

Demultiplexer 10, an oscillator 11 for providing the energy for the transmission electrodes

and an oscillator 12 for driving the demultiplexer.

The evaluation electronics mainly consists of a power supply, a

Amplifier 13, a demodulator 14, a comparator 15, a microprocessor 16 with

Memory and filters for the suppression of external and interference signals.

The transmitter and receiver electrodes are cast in a sensor carrier. This

form a capacitive scanner 4 across the entire document collection width

strip-shaped receiving electrode runs across the document feed direction. The

Transmitting electrodes are arranged parallel to the receiving electrode. The distance one

Transmitting electrode to receiving electrode becomes electrical by the document typical

conductive test characteristics determined. By lining up several

Transmitting electrodes are given the ability to work capacitively in the longitudinal axis

Scanners 4 capture several electrically conductive features simultaneously. The one with this

The arrangement achievable resolution depends on the number of transmitting electrodes used.

In this exemplary embodiment, the resolution is at one scannable point per mm

both lengthways and crossways. The minimum distance between neighboring ones Transmitting electrodes are limited by the interfering capacitive coupling. Around

to prevent this and to reduce interfering influences from neighboring transmitter electrodes,

the transmission electrodes are controlled in succession by a multiplexer 10. Through the

The arrangement of the transmission electrodes over the entire document collection width takes place

Checking of documents in a neutral position. This means that a pre-sorting of several

Documents with a document processing machine are omitted.

FIG. 7 shows the schematic representation of the scanner 4 with a multiplicity of transmission electrodes

the 5 and a receiving electrode 6. The control and evaluation takes place after the in

Fig. 6 block diagram shown.

8 shows the schematic representation of an embodiment of the capacitively operating

Scanners with a transmitting electrode 17 and a plurality of receiving electrodes 18. In

6 is the transmission electrode 17 by means of an oscillator

driven. The signals of the receiving electrodes 18 are processed by means of multiplexers.

The further evaluation electronics, consisting of power supply, an amplifier, a

Demodulator, a comparator, a microprocessor with memory and filters for

Suppression of external and interference signals, is similar to the block diagram according to FIG. 6.

Fig. 9 shows the schematic representation of a further embodiment of the capacitive

working scanner with a plurality of transmission electrodes 19 and a variety of

Receiving electrodes 20. These are alternately arranged in a row.

Accordingly, both the drive signals of the transmission electrodes 19 and

Evaluation signals of the receiving electrodes 20 by means of multiplex or demultiplexing

processed. FIG. 10 shows a schematic illustration of the capacitive scanner 4 and one to

inspection document in side view. The OVD contains partial metallizations 21

and an electrically insulating carrier film 22.

11 shows a schematic section through an OVD with a carrier layer 23 and one

partially metallic layer 24. The partially metallic layer 24 includes several

demetallized segments 25. In FIG. 12 the associated evaluation signal is in one

Voltage-time diagram shown.

13 shows a schematic section through an OVD with a carrier layer 26 and one

discontinuous metallization layer 27. The discontinuous metallization

Layer 27 contains segments 28, 29, 30, 31, 32 with different electrical

Conductivity. 14, the associated evaluation signal is in a voltage-time

Diagram shown.

In the present invention, the structure was based on specific exemplary embodiments

Diffractive optical security elements and a device for testing such

Elements explained. However, it should be noted that the present invention is not limited to

Details of the description in the exemplary embodiments are limited, since within the scope

changes and modifications are claimed. So be next

the diffractive optical security element also other electrically conductive

Features detected by the device according to the invention. The targeted combination

Diffractive optical security elements with other electrically conductive features

results in a further coding. At the same time, other electrically conductive

Inspection characteristics, e.g. an electrically conductive security thread or coding

Classify electrically conductive paint using the test device according to the invention.

Claims

claims 1. Structure of diffractive optically effective security elements in documents, thereby characterized in that the diffractive optical security element with a targeted electrical coding of information, consisting of a discontinuous metallization layer and / or partially metallically conductive layers and / or zones of metallic layers in different planes. 2. Structure according to claim 1, characterized in that the shape of the coding geometrical figures, in particular lines, grid lines, arcs and / or circles. 3. Structure according to claim 1, characterized in that the shape of the coding regular or irregularly arranged geometric figures, in particular lines, Grid lines, arcs and / or circles are similar. 4. Structure according to claim 1, characterized in that a top view demetallized zone (3) has the shape of a meander. 5. Structure according to claim 1, characterized in that alternately metallized strip-shaped zones (7) and demetallised strip-shaped zones (8) parallel to one another are arranged, the strip-shaped zones being parallel or perpendicular in plan view to the document transport direction. 6. Structure according to claim 1, characterized in that the distance between two Zones of the same and / or different electrical conductivity with the shortest Distance between two electrodes corresponds. 7. Structure according to claim 6, characterized in that the distance between two Zones of the same and / or different electrical conductivity at least 0.1 mm is. 8. Structure according to one or more of the preceding claims, characterized characterized in that the metallized zones (7) by one or more perpendicular to it running demetallized zones (9) are interrupted. 9. Structure according to one or more of the preceding claims, characterized characterized in that the optically diffractive security element is an OVD (1). 10. Structure according to one or more of the preceding claims, characterized characterized in that the diffractive optical security element is a hologram. 11. Structure according to one or more of the preceding claims, characterized characterized in that the diffractive optical security element is a kinegram. 12. Device for checking documents with effective diffraction Security elements, characterized by a capacitive scanner (4), the Width is greater than the largest width of a document consisting of a Stringing together a large number of adjacent electrodes, one Control electronics and evaluation electronics for comparing the signal curve of the checking document with corresponding reference waveforms. 13. Vorrichtimg according to claim 12, characterized in that a plurality of Electrodes are arranged side by side and / or in several rows. 14. The apparatus according to claim 12, characterized in that the control electronics from a power supply, a multiplexer (10), an oscillator (11) for provision the energy for the transmitting electrodes (5) and an oscillator (12) for controlling the Multiplexer (10) exists. 15. The apparatus according to claim 12, characterized in that the evaluation electronics from a power supply, an amplifier (13), a demodulator (14), a Comparator (15), a microprocessor (16) with memory and filters for suppression of external and interference signals. 16. The device according to one or more of claims 12 to 15, characterized characterized in that the smallest distance between electrodes is less than 0.5 mm. 17. The device according to one or more of claims 12 to 16, characterized characterized in that the distance between a transmitting electrode (5) and the Receiving electrode (6) is at least 0.5 mm. 18. The device according to one or more of claims 12 to 17, characterized characterized in that the device in high-speed document processing machines is arranged. 19. The device according to one or more of claims 12 to 18, characterized characterized in that the device is arranged in hand-held devices. 20. The device according to one or more of claims 12 to 19, characterized characterized in that the device is arranged in document readers. 21. The device according to one or more of claims 12 to 20, characterized characterized in that the scanner is arranged over the entire width of the document, that different visually perceptible diffractive optically effective security elements with the same electrical properties on one and the same document Microprocessor to be compared. 22. The device according to one or more of claims 12 to 21, characterized characterized in that the scanner is arranged over the entire width of the document, that with visually perceptible diffractive optically effective security elements different electrical properties on the same document Microprocessor to be compared.