HK1026971A - Application and method for checking documents with effective optical diffraction security layer - Google Patents

Description

Use and method for checking documents with a security layer with diffractive optical effect

The invention relates to an application and a method for checking documents.

Hitherto, security layers with diffractive optical effects (security layers), in particular holograms, have been examined with expensive optical examination equipment. In this case, the test object must be accurately positioned. The overall inspection process takes so long that this inspection method cannot be used in a rapid processing machine. For example, banknotes with holographic security markings cannot be tested in banknote counting machines, since such banknote counting machines operate at speeds of 500 and 1500 sheets per minute and above. DE2747156 describes a method and a testing device for verifying the authenticity of identification cards using holograms. The hologram was simulated and visually observed. This method is not suitable for performing rapid, efficient, human-independent tests. EP0042946 describes a device for generating a scanning pattern, which is examined by means of a laser, a reflection optical system and a lens system and a light sensor. The costs required in this case are also high. If the test substance is not classified, the cost is higher. To avoid pre-classification, anti-counterfeiting inspection systems require multi-level arrangements.

The object of the present invention is to overcome the disadvantages of the prior art and to propose an application and a method which permit rapid, person-independent and cost-effective inspection of security layers with diffractive optical effects, in particular of documents with holograms. The method allows documents with a security layer having a diffractive optical effect to be tested both in document testing devices and currency processing machines and in hand-held testing instruments.

This object is achieved by the features given in the characterizing portion of claim 1.

The use of holograms and other security layers with diffractive optical effects for the protection of documents and other documents of value and banknotes against forgery is an increasingly common method nowadays. Rapid verifiability is also an additional level of security in the authentication of diffractive optical effect layers as security features. The diffraction light effect layer is composed of a metalized layer and other substances. The metallization layer is electrically conductive. The conductivity varies accordingly depending on the layer thickness. The diffraction effect layer has a discontinuous metallization layer and/or a partial metal layer and/or a metal layer region on different planes. Different methods of measuring conductivity are known. This contactless capacitance measurement has proven to be feasible. In this method of verifying security documents, the capacitive coupling between the transmitter and the receiver and the transfer of energy between the transmitter and the receiver are electromagnetically lapped using a conductive security material. The subsequent electronic analysis device compares the signal image of the test object with a corresponding reference signal. The comparison provides a classification signal for further processing. Accordingly, the checking device can be stopped at this point and documents identified as counterfeit money can be sorted out, for example. The signal image depends on the structure of the metallization layers of the diffractive optical effect layer. If the diffractive optical effect layer has an intermittent metallization layer, the respective regions of the metallization layer have different conductivities. Practice has shown that this different conductivity contributes to the signal image.

The conductivity is combined with other anti-counterfeiting marks of the diffraction light effect layer for inspection, so that the inspection reliability can be further improved. The mark and the electrical conductivity can be simultaneously verified by attaching a security mark in the non-metallized areas between the discontinuous metallized layer and/or the partial metal layer and/or the metal layer areas on different planes. The authenticity signal of the further sensor for determining the authenticity is logically connected to the sensor for measuring the conductivity by means of an electronic evaluation device. At the output of the electronic analysis device, a signal classifying the diffractive optical effect layer is awaited for further processing. The additional security feature has fluorescent, phosphorescent or light-absorbing properties or is distinguished from its environment by different magnetic properties. Accordingly, optical or magnetic sensors are used. To reduce detection and measurement errors, a sensor mount is preferably used. The sensor carrier can accommodate all sensors for detecting the security feature. It also minimizes the distance between the sensors and always places the sensors in a certain position. To avoid interference factors, the sensor carrier is securely attached to a mounting plate that supports the electronic analysis device. The entire test device is housed in the processing machine, so that the additional costs of transporting the test objects do not have to be increased.

The description and the drawings may also indicate features of the invention, other than the claims, which features are individually or in several separate combinations represent advantageous and patentable embodiments claimed herein. An embodiment of the present invention is shown in the drawings, and the present invention will be described in detail with reference to the embodiment. In the drawings:

FIG. 1 is a schematic cross-sectional view of a processing machine with a checking device;

FIG. 2a is a cross-sectional view of a hologram with non-metalized areas;

FIG. 2b is a graph of voltage versus time of an analysis signal;

FIG. 3a is a cross-sectional view of a hologram with an interrupted metallized layer;

FIG. 3b is a graph of voltage versus time of an analysis signal;

FIG. 4a is a cross-sectional view of a hologram with a UV security marking;

FIG. 4b is a graph of the voltage versus time of the analytical signal for conductivity detection;

fig. 4c is a voltage-time plot of the analytical signal of the UV sensor.

The checking method according to the invention provides that suitable sensors are mounted in suitable positions on the banknote counter. The sensor for detecting the conductivity is arranged to monitor the entire width of the banknote so that it can inspect the banknote in a centered position. Optical or mechanical sensors provide a time-controlled reference signal for the checking device 4 when the banknote is present. While simultaneously activating a sensor that verifies the authenticity of the hologram. By noting the entire time window from the beginning to the end of the banknote, the location of the hologram on the banknote can be determined.

Fig. 1 shows the arrangement of the checking device 4 in the banknote transport path. The banknote counter comprises a feed-in wheel 1, a transport wheel 2, a banknote guide device 3 and a checking device 4.

Fig. 2a is a cross-sectional view of a hologram with a carrier layer 11 and a local metal layer 12. The partial metal layer 12 comprises several non-metallised regions 13. Fig. 2b shows the relevant analysis signal in the form of a voltage-time diagram.

Fig. 3a is a cross-sectional view of a hologram with a carrier layer 11 and an interrupted metallised layer 14. The discontinuous metallization layer 14 comprises regions 15, 16, 17, 18, 19 with different electrical conductivities. Fig. 3b shows the relevant analysis signal in the form of a voltage-time diagram.

Fig. 4a is a cross-sectional view of a hologram with a carrier layer 11 and an interrupted metallised layer 20. The intermittent metallized layer 20 includes a non-metallized region 21 and an additional anti-counterfeit verification mark. These security features are fluorescent pigments 22 which are excited by UV light during the test and are detected during the test by means of a light sensor. The additional security check mark is preferably located in the non-metallized area 21. Fig. 4b shows the relevant evaluation signal of a capacitively operating sensor for checking the conductivity in the form of a voltage-time diagram. Fig. 4c shows the change in the analytical signal of the light sensor in the form of a voltage-time diagram.

In the present invention, the examination of documents with a diffractive light-effect security layer is described with the aid of a specific embodiment. It is to be understood that the invention is not to be limited to the details described in the examples, but that modifications and variations are possible within the scope of the appended claims.

Claims (16)

1. Use of a method for the verification of documents with the aid of capacitive coupling between transmitter and receiver and the transfer of energy between transmitter and receiver by means of an electrically conductive security material, characterized in that the electrical conductivity of a document is determined and analyzed for the authenticity verification of a document with a diffractive light-effect security layer comprising an interrupted metallized layer (14) or a partial metal layer (12, 20) or metal layer regions on different planes.

2. Use of the method according to claim 1, characterized in that the conductivity is determined and analyzed for authenticity checking of documents with a diffractive optical effect security layer comprising an interrupted metallized layer (14) and a partial metal layer (12, 20).

3. Use of the method according to claim 1, characterized in that the conductivity is determined and analyzed for authenticity checking of documents with a diffractive optical effect security layer comprising an interrupted metallization layer (14) and metal layer regions on different planes.

4. Use of the method according to claim 1, characterized in that the electrical conductivity is determined and analyzed for authenticity checking of documents with a diffractive optical effect security layer comprising local metal layers (12, 20) and metal layer regions on different planes.

5. Use of the method according to claim 1, characterized in that the electrical conductivity is determined and analyzed for authenticity checking of documents with a diffractive light-effect security layer comprising discontinuous metallization layers (14) and partial metal layers (12, 20) and metal layer regions on different planes.

6. Use of the method according to one of claims 1 to 5, characterized in that the security marking is verified in the unmetallized areas additionally present between the discontinuous metallization layer (14) and/or the partial metal layers (12, 20) and/or the metal layer areas on different levels.

7. Use of the method according to claim 6, characterized in that the fluorescence properties of the additional security feature are checked.

8. Use of the method according to claim 6, characterized in that the phosphorescent properties of the additional security marking are checked.

9. Use of the method according to claim 6, characterized in that the light-absorbing properties of the additional security feature are checked.

10. Use of the method according to claim 6, characterized in that the additional security feature is checked for its magnetic properties in relation to its environment.

11. Use of a method according to any of the preceding claims, wherein the diffractive optical effect security layer is a hologram.

12. Use of the method according to one of the preceding claims, characterized in that the hologram is checked in a rapid processing machine which can process up to 2000 documents per minute.

13. Use of the method according to one of the preceding claims, characterized in that the hologram is checked in a hand-held instrument.

14. Method for the inspection of documents using capacitive coupling between transmitter and receiver and energy transfer between transmitter and receiver by means of conductive security material, characterized in that the document to be inspected, which contains discontinuous metallization (14) and/or partial metal layers (12, 20) and/or metal layer regions on different planes with a diffraction-effective security layer, is passed at a defined speed through an electronic sensor device, the energy is transferred from one or several transmitting electrodes through the metallization in capacitive form to one or several receiving electrodes, the signal present at the single or several receiving electrodes is amplified by means of an electronic evaluation device, compared with a reference signal, and a signal classifying the document is provided at the output of the evaluation electronics, to be further processed.

15. Method according to claim 14, characterized in that the document with the diffractive optical effect security layer is inspected in at least two different inspection directions.

16. Method according to claim 14, characterized in that the classification signal is logically connected to the authenticity signal of the additional security feature by means of the electronic evaluation device after it has been checked by means of a further sensor, and a composite signal for classifying the document is provided at the output of the electronic evaluation device for further processing.