EP3503049B1 - Device and method for detecting a machine-readable security feature of a valuable document - Google Patents

Description

The invention relates to a device for verifying a machine-readable security feature of a value document and a method for verifying a machine-readable security feature of a value document.

Documents of value such as notes of value or, for example, banknotes, checks, shares, papers with security imprints, certificates, ID cards, passports, admission tickets, tickets, vouchers, identification or access cards or the like can be provided with security features on their front, back and / or embedded in the material in order to make counterfeiting difficult or impossible and to be able to check their authenticity. In the exemplary case of a bank note, one type of security feature can be an area printed with luminescent (e.g. phosphor and / or fluorescent) ink. Since the luminescence, the reflection and / or transmission behavior of such a region of the bank note can only be imitated with great effort, this represents an effective security feature which can at the same time be machine-checked.

An automatic authenticity check of a bank note takes place, for example, by a device provided in a bank machine for the detection of security features, for example when a bank note is removed from the bank machine or is entered into it. In this case, the bank note is usually transported through the device, the printed area is irradiated by means of a radiation source, the specific reflection, transmission and / or luminescence behavior is detected by a sensor and evaluated by means of an evaluation unit; if the security feature is not detected or is detected incorrectly, it takes place an identification of the bank note as a (potential) counterfeit and the bank note is removed from circulation.

During transport through the device, the bank note can adopt any two orientations, i.e., either with the front or the back pointing perpendicular to the transport direction, so that the luminescent area can be on one of the two sides with respect to the transport direction. As a result, both sides of the banknote must be checked in the device. To achieve this, the luminescent region is usually detected by reflection, ie the bank note is irradiated from one side and the reflection and / or luminescence is detected on the same side, or by transmission, ie the bank note is detected from one side irradiated and the radiation and / or luminescence passing through is detected on the other side. In both cases there are active components of the device (e.g. radiation sources and / or sensors) on both sides of the banknote.

As a result, problems arise with a conventional device in that it requires a large amount of space, the active components and their cabling are required on two sides and the components have to be synchronized depending on the transport speed in order to be able to reliably detect the security feature on both sides.

For example is off EP 2 706 511 A1 a device for acquiring recordings of a sheet is known, which has a transport device, a radiation emitter, a sensor, a reflector and an evaluation unit.

In response to this, a device for verifying a machine-readable security feature of a value document according to claim 1 and a corresponding method according to claim 12 are provided provided which enable a secure automatic detection of a security feature of a value document in a device. Further embodiments of the device and of the method are described in the respective dependent claims.

A device according to an exemplary embodiment has a transport device, a radiation emitter, a sensor, a reflector and an evaluation unit on. The device can be used to handle documents of value, that is to say to receive them, transport them through the device by means of the transport device, check them and issue them. The value document (for example a bank note) can be a flat, for example rectangular, object made of, for example, paper or other fiber material, plastic or a combination thereof and can have a first flat side and a second flat side opposite it. In the case of a rectangular document of value, this can have a long edge and a relatively short edge. The device can for example be provided in an ATM. In addition, the device can also be provided in numerous types of machines which handle documents of value, for example in deposit machines, ticket machines, food machines and drinks machines. The structure and function of such machines are sufficiently known that a description is not given.

The transport device is set up to transport the document of value on a (e.g. flat or curved) transport plane in a transport direction through the device (e.g. by means of roller and / or belt conveyors). The transport plane can (e.g. at least substantially) be oriented perpendicular to a direction of gravity or (e.g. at least substantially) parallel to the direction of gravity. During the transport of the value document through the transport device, the flat sides of the value document extend (e.g. at least essentially) parallel to the transport plane.

The radiation emitter is arranged on the first flat side and set up radiation in the direction of the first flat side to emit, for example. When the value document is transported past it. The emitted radiation is set up, a luminescence radiation To stimulate security features of the value document, for example. A region of the value document which is suitable for phosphor and / or fluorescence. Such a region can be located on one or each of the flat pages and / or embedded in the material of the document of value. The radiation is also set up to at least partially pass through the value document. For example, the emitted radiation can be adapted to the type of document of value and the security feature, for example by using different radiation emitters.

The sensor is arranged on the first flat side. The sensor is set up to receive at least part of the luminescence radiation and / or the emitted radiation and to output a corresponding signal. For example, the emitted radiation can be (e.g. at least essentially) radiation reflected on the value document and / or radiation that has passed through the value document. The different reflection and transmission behavior and the luminescence behavior of the security feature in comparison to the rest of the bank note can be detected by the sensor.

For example, the sensor and the radiation emitter can, for example, be arranged jointly (e.g. synchronously), e.g. movable parallel to the transport plane, e.g. (at least essentially) transversely to the transport direction. Furthermore, the sensor and the radiation emitter can, for example, be designed as an integral unit.

The reflector is arranged on the second flat side (for example, at least substantially parallel to the second flat side). The reflector can extend (for example at least essentially) transversely to the transport direction, for example with a width which (for example at least essentially) corresponds to the value document, ie the reflector can correspond at least to the length of an edge of the value document. The reflector is further set up to at least partially reflect the emitted radiation of the radiation emitter and / or the luminescence radiation of the security feature of the value document passing through the value document to the sensor. The reflector can furthermore be arranged in such a way that a beam path of the radiation emitter-reflector-sensor type is formed. The reflector can, for example, also be curved in such a way that the radiation reflected therefrom is focused on the sensor. For example, the reflector can reflect radiation in a wavelength-selective manner, for example matched to the wavelength of the emitted radiation and / or the luminescence radiation.

The evaluation unit is set up to control the radiation emitter and to receive the signals output by the sensor. The control can include, for example: Switching the radiation emitter on / off depending on the transport speed. Furthermore, the evaluation unit can be implemented as hardware, e.g. as an integrated circuit (e.g. in the form of an FPGA, ASIC, microcontroller, etc.), and the evaluation unit can, for example, process the signals from the sensor and determine the presence of a security feature, e.g. Execution of software, by means of which method steps for the detection of a security feature of a value document are implemented.

The radiation emitter is set up to emit the radiation as infrared radiation, for example Range of approximately 750 nm-3000 nm. For example, the emitted radiation can have a near-infrared spectrum, preferably in approximately 780 nm-1400 nm, and more preferably in around 850 nm - 1000 nm. For example, radiation in the visible spectrum (eg in around 380 nm - 750 nm) or in the ultraviolet spectrum (eg in around 200 nm - 380 nm) can be emitted.

The radiation emitter can, for example, be a light-emitting diode (hereinafter: LED for short) (e.g. an organic LED); however, other radiation emitters which can emit an IR spectrum are also possible. For example, several (e.g. separate) LEDs can be used as radiation emitters, which, for example, emit in different spectra in order to be suitable for detecting different types of security features.

The sensor is a photodiode which is matched to the spectrum of the radiation emitter. For example, the maximum sensitivity of the photodiode lies in a wavelength range which corresponds to a maximum of the radiation emitted and / or the luminescence radiation. The tuning can be done, for example, by an optical filter, which filters undesired wavelengths (e.g. ambient light). For example, the sensor can be enclosed (e.g. encapsulated, e.g. potted) by a suitable material (e.g. plastic).

The sensor and the radiation emitter can, for example, be at least partially enclosed (e.g. encapsulated, e.g. cast) by a material (e.g. plastic) that is permeable to the luminescent radiation and the emitted radiation, e.g. to fix these components in the device and to protect against contamination /Damage.

The reflector can, for example, be arranged at a distance (for example at least substantially perpendicular) to the flat side of the value document, which is, for example, approximately at most 10 mm, preferably approximately 5 mm and more preferably approximately 1.5 mm, with a small distance being the Share of reflected radiation increased.

The radiation emitter has a first partial radiation emitter (e.g. a first LED) and a second partial radiation emitter (e.g. a second LED) and the sensor is arranged along a direction transverse to the transport direction between the first partial radiation emitter and the second partial radiation emitter .

An optical axis of the sensor can, for example, be (at least substantially) perpendicular to the transport plane, with a distance of the sensor to the flat side of the value document, for example, approximately 1 mm - 3 mm, preferably approximately 1 mm - 2 mm and more preferably approximately 1 mm, with a small distance increasing the irradiation intensity of the value document.

A viewing area (for example along the, for example, symmetrical to the optical axis) of the sensor can be set up, for example, in such a way that a minimum dimension of the security feature of the value document that can be detected by the sensor, e.g. transverse to the transport direction, which is based on a maximum signal strength of the sensor when detecting the security feature can be detected with a signal strength of at least 50%, is approximately 5 mm - 10 mm and preferably approximately 6.5 mm - 7.5 mm. For example, the distance of the sensor from the value document, the sensitivity of the sensor, the field of view of the sensor, the transport speed, the intensity of the emitted radiation, etc. can be varied for this purpose.

An optical axis of the radiation emitter with respect to the transport plane can e.g. be inclined in such a way that its point of intersection with the transport plane and the reflector lies in the field of vision of the sensor (e.g. intersects the optical axis of the sensor).

In the device, for example, the sensor can interact with the radiation emitter as a detection channel.

For example, the sensor and the radiation emitter of a detection channel are calibrated together, e.g. to compensate for fluctuations in component characteristics (e.g. tolerances). Such a detection channel can, for example, detect a strip of the value document in the transport direction when the value document is being transported (which, for example, corresponds to the field of view of the sensor). For example, depending on the type (e.g. size) of the value document, several acquisition channels can be arranged next to one another at right angles to the transport direction of the value document. For example, five, six, seven, eight, nine, ten, eleven or more detection channels can be provided. The distance between the optical axes of the sensors and such detection channels can be, for example, about 30 mm, preferably about 20 mm and more preferably about 17.5 mm, in order to be able to detect even small security features.

The value document can be, for example, one of the following: a bank note, a check, a proof of identity, a passport, a ticket and a share document.

The transport device can, for example, be set up in such a way that the value document (e.g. the bank note) can be transported through the device with one of its long edges first.

The method for detecting a machine-readable security feature of a document of value with a device according to the invention and according to an exemplary embodiment, wherein the document of value is transported between a sensor and a radiation emitter on the one side and a reflector on the other side, comprises: Transporting the document of value with a predetermined transport speed (e.g. in about 1.8 m / s - 3.4 m / s), irradiation (e.g. with infrared radiation), through the radiation emitter, of the document of value for a predetermined period of time (e.g. in about 75 µs), e.g. during and / or after irradiation, detection, by the sensor, several Measured values over a predetermined period of time (for example approximately 400 μs) which result in luminescence radiation (for example fluorescence and / or phosphorescence) of the security feature that is excited by the irradiation and / or radiation reflected from the value document and / or from the reflector Corresponds, forming, by an evaluation unit, a signal curve from the measured values, and evaluating, by the evaluation unit, whether a security feature is present, by comparing the detected signal curves (eg partial areas thereof). For example, the recorded signal profiles can be compared with one another or with a predetermined reference signal profile. Furthermore, since a position of the security feature is unknown, the method can be run through (repeatedly) for as long as the value document is transported past the sensor.

The evaluation of the signal curves can, for example, show that a security feature is present if a value formed when the difference between the signal curves is greater than a reference value.

Exemplary embodiments of the device and of the method are shown in the figures or are explained in more detail below.

Figur 1

eine schematische Anordnung (Seitenansicht) einer Transportvorrichtung, einer Auswertungseinheit, eines Strahlungsemitters, eines Sensors, eines Reflektors und einer Banknote in einer Vorrichtung zum Nachweis eines Sicherheitsmerkmals einer Banknote,

Figur 2

eine schematische Darstellung (Vorderansicht) eines Erfassungskanals mit zwei LEDs und einer Fotodiode in der Vorrichtung zum Nachweis eines Sicherheitsmerkmals einer Banknote,

Figur 3

eine schematische Anordnung (Draufsicht) von elf Erfassungskanälen in einer Vorrichtung zusammen mit mehreren möglichen Positionen von Banknoten in der Vorrichtung zum Nachweis eines Sicherheitsmerkmals einer Banknote und

Figur 4

ein Flussdiagramm eines Verfahrens zum Nachweis eines Sicherheitsmerkmals einer Banknote.

Show it:

Figure 1

a schematic arrangement (side view) of a transport device, an evaluation unit, a radiation emitter, a sensor, a reflector and a bank note in a device for detecting a security feature of a bank note,

Figure 2

a schematic representation (front view) of a detection channel with two LEDs and a photodiode in the device for detecting a security feature of a banknote,

Figure 3

a schematic arrangement (top view) of eleven detection channels in a device together with several possible positions of banknotes in the device for detecting a security feature of a banknote and

Figure 4

a flow chart of a method for detecting a security feature of a bank note.

In the following detailed description, reference is made to the accompanying drawings, which form a part hereof, and in which there is shown, for purposes of illustration, specific embodiments in which the invention may be practiced. In this regard, directional terminology such as "up", "down", "left", "right", etc. is used with reference to the orientation of the figure (s) being described. Because components of embodiments can be positioned in a number of different orientations, the directional terminology is used for purposes of illustration and is in no way limiting. It is further understood that the indexing of features with, for example, "first (s / r)", "second (s / r)", etc. is also used for illustration purposes and is in no way restrictive. It is also understood that the features of the various exemplary embodiments described herein can be combined with one another, unless specifically stated otherwise. Therefore, the following detailed description is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.

In the figures, identical or similar elements are provided with identical reference symbols, as far as this is appropriate. Furthermore, the thickness of lines in the figures may be exaggerated for better illustration; For example, the thickness of a value document or its security feature can be exaggerated in the figures but actually be small in relation to other dimensions.

The Fig. 1 shows a schematic side view of a device 1 for checking a bank note 3 by detecting a security feature 3 'of the bank note 3, the device 1 having: a transport device 5, an evaluation unit 7, a radiation emitter 9, a sensor 11 and a reflector 13 Fig. 1 The device shown does not fall under the subject matter of claim 1.

The bank note 3 is a rectangular, flat object made of, for example, paper with a first flat side 3a and a second flat side 3b opposite the first flat side 3a. The paper (or another fiber material, e.g. also made of plastic) is partially permeable to radiation in the infrared spectrum (IR spectrum or IR for short), ie at least part of the emitted IR radiation can pass through the bank note 3 during a other part of it is reflected by the banknote 3. The spectrum is preferably a near-infrared spectrum in the range from approximately 850 nm to 1000 nm. The bank note 3 also has two long edges 3c, 3d and two edges that are short in relation to them. The security feature 3 'is provided on at least one of the flat sides 3a, 3b, which is defined as an area of the bank note 3 that is printed with phosphorescent ink. This can be, for example, the specification of the nominal value of the banknote. The phosphorescent ink can be excited by the radiation in the near-infrared spectrum, in which case a phosphorescent radiation is then emitted which, for example, also has a near-infrared spectrum. The bank note 3 can have further (for example magnetic, reflective in the ultraviolet spectrum, etc.) security features that can be checked by other sensors of the device 1, but this is not explained further here. In addition, the bank note 3 is not restricted to one type of bank note, but instead represents a large number of different bank notes, for example different denominations (physical size of the bank note) one or different Currencies. In the further description, for the sake of simplicity, a case is described in which the bank note 3 with its first flat side 3a and the security feature 3 'points upwards and is transported through the device 1 with one of its long edges first; however, it is also possible that the second flat side 3b faces upwards, the banknote 3 is transported through the device 1 with one of its short edges first and / or the security feature 3 'is arranged in the material of the banknote 3 or faces downwards.

The banknote 3 is from the right side (in the Fig.1 ) can be entered into the device 1, for example by a (not shown) bank note feeder, and can be transported by the transport device 5 on a transport plane TE (dotted line) in a transport direction TR through the device 1 to the left. The first and second flat sides 3a, 3b are here arranged in the transport plane TE. Here, the transport device 5 has, for example, at least one pair of rollers 5a, 5b, which are arranged axially parallel to the conveying direction above and below the transport plane TE and form a gap in which the banknote 3 can be transported through the rollers 5a, 5b ( Fig.1 shows two pairs of rollers as an example). It should be noted that any other transport mechanism can also be used in this context. For this purpose, the rollers 5a, 5b each contact one of the flat sides 3a, 3b of the bank note 3 and at least one of the rollers 5a, 5b is driven, for example by an electric motor (not shown). Furthermore, the transport device can have a bank note guide (not shown) which prevents the bank note from leaving the transport level; this can be, for example, a guide plate on which the bank note rests (eg slides along) during transport. The transport speed can be controlled by the evaluation unit 7, which for this purpose is connected to the transport device 5 (not shown). For example this is Transport speed approximately 1.8 m / s - 3.4 m / s, which ensures both rapid transport of the bank note 3 and sufficient duration for the detection of a security feature 3 '. After passing through the device 1, the bank note 3 can be dispensed on the left side of the device 1, for example into a storage compartment (not shown).

The radiation emitter 9 is designed here as an LED which emits radiation in the near-infrared spectrum (e.g. at an intensity maximum of approximately 950 nm). The LED 9 is electrically connected to the evaluation unit 7, for example by means of a line 21 (dotted line) and can be switched on and off in a controlled manner by this. Alternatively, the connection can also be a radio connection or an optical connection. Furthermore, the LED 9 is arranged above the transport plane TE and emits the radiation in the direction of the first flat side 3a of the bank note 3. The IR radiation emitted by the LED 9 is selected or regulated in such a way that a luminescence of the security feature 3 'is excited. In this case, the LED 9 emits IR radiation, which causes the security feature 3 'to phosphoresce. The security feature 3 ′ then emits phosphorescent radiation in the excited state, the intensity of which decreases at a predetermined rate per unit of time after the end of the IR radiation (depending on the phosphorescent material).

On the same side of the transport plane TE and in the transport direction TR after the radiation emitter 9, a photodiode 11 is attached as a sensor 11 (for example, a reverse arrangement is also possible, for example at low transport speeds). The photodiode 11 is sensitive to the phosphorescence radiation produced by the phosphorescence of the security feature 3 '. The photodiode 11 has a sensitivity maximum of approximately 950 nm and is insensitive to radiation in the spectra below approximately 750 nm and above approximately 1100 nm. That is, the spectra of the photodiode 11 and the LED 9 as well as the corresponding phosphorescent radiation are on top of one another Voted. The photodiode 11 is electrically connected to the evaluation unit 7 by means of a line 23 (dotted line) and outputs a signal to the evaluation unit 7 which corresponds to the radiation intensity detected by the photodiode 11. The electrical connection of a photodiode to an evaluation unit and a signal processing thereof are sufficiently known that no explanations are given in this regard.

• ein erster Strahlungspfad 25a (strichlierte Linie) der IR-Strahlung ausgehend von der LED 9 zur Banknote 3 (Teilreflektion) und zur Fotodiode 11, und
• ein zweiter Strahlungspfad 25b (strichlierte Linie) der Phosphoreszenzstrahlung ausgehend vom Sicherheitsmerkmal 3' (erste Flachseite 3a, d.h., der Fotodiode 11 zugewandt) und zur Fotodiode 11.

The photodiode 11 is oriented to the transport plane TE and covers an area (field of view) of the banknote 3 which can be irradiated by the LED 9, for example the security feature 3 'of the banknote 3 (for a simplified illustration, the security feature 3' is shown at a position which is offset in the transport direction TR with respect to the photodiode 11; however, the security feature 3 'can be detected at any position which is in the field of view of the photodiode 11). Through the in the Fig.1 The arrangement shown, the following radiation paths are implemented:

• a first radiation path 25a (dashed line) of the IR radiation proceeding from the LED 9 to the bank note 3 (partial reflection) and to the photodiode 11, and
• a second radiation path 25b (dashed line) of the phosphorescent radiation starting from the security feature 3 ′ (first flat side 3a, ie facing the photodiode 11) and to the photodiode 11.

• ein dritter Strahlungspfad 27a (strichlierte Linie) der IR-Strahlung ausgehend von der LED 9, durch die Banknote 3 hindurch, zum Reflektor 13 (Reflexion), durch die Banknote 3 hindurch und zur Fotodiode 11 und
• ein vierter Strahlungspfad 27b (strichlierte Linie) der Phosphoreszenzstrahlung ausgehend vom Sicherheitsmerkmal 3', durch die Banknote 3 hindurch, zum Reflektor 13 (Reflexion), durch die Banknote 3 hindurch und zur Fotodiode 11.

On the other side of the transport level TE (below in the Fig.1 ) the reflector 13 is attached, which is set up to reflect IR radiation in the spectrum of the LED 9 and the phosphorescent radiation. Here the reflector 13 is aligned and positioned parallel to the transport plane TE so that the following radiation paths are implemented:

• a third radiation path 27a (dashed line) of the IR radiation starting from the LED 9, through the bank note 3 through, to the reflector 13 (reflection), through the banknote 3 and to the photodiode 11 and
• a fourth radiation path 27b (dashed line) of the phosphorescent radiation starting from the security feature 3 ′, through the banknote 3, to the reflector 13 (reflection), through the banknote 3 and to the photodiode 11.

By means of the four radiation paths 25a, 25b, 27a, 27b, it is possible to irradiate the security feature 3 'on each of the flat sides 3a, 3b or to guide the phosphorescent radiation to the photodiode 11: part of the IR radiation emitted by the LED 9 hits directly on the security feature 3 '(flat side 3a) and the other part passes through the banknote 3, is reflected by the reflector 13 and also hits the security feature 3' (from the second flat side 3b after the reflected IR radiation into the banknote 3 has occurred). The security feature 3 ′ is thus also irradiated with IR radiation, which would no longer be available without the reflector 13. Analogously, phosphorescent radiation from the security feature 3 ′ is passed directly (starting from flat side 3 a) and indirectly (via flat side 3 b) to photodiode 11. With this arrangement it is also possible to sufficiently irradiate a security feature in the material of the banknote 3 (not shown) in order to ensure proof of the security feature embedded in the banknote 3.

Referring to the Fig. 2 a detection channel 31 with two LEDs 9-1, 9-2 and a photodiode 11 in the device 1 for detecting a security feature 3 'of a bank note 3 is shown schematically. The Fig. 2 a section of the device 1 in front view (transport direction TR of the bank note 3 into the plane of the drawing). The LEDs 9-1, 9-2 and the photodiode 11 are the same as those with reference to FIG Fig.1 are described. The detection channel 31 is arranged on the first flat side 3a of the bank note 3 and is formed by the LEDs 9-1, 9-2 and the photodiode 11 on a circuit board 33 (circuit board, eg a printed circuit board (PCB)). The housing 35 is used to protect against contamination and to stabilize the LEDs 9-1, 9-2, the photodiode 11 and the circuit board 33 in the housing 35. The housing 35 is at least partially transparent to the emitted radiation and the phosphorescent radiation Material 37 (e.g. IR-permeable plastic) encapsulated. The material 37 creates an optically uniform medium in the housing 35 and further protects the components. However, it is alternatively possible to dispense with the material 37 and / or the housing 35 if the detection channel 31 is fastened directly in the device 1. Furthermore, the housing 35 has, on its side facing the bank note 3, a window 39 which is transparent to the emitted radiation and the phosphorescent radiation. As already for the Fig.1 described are the photodiode 11 by means of the line 23 and the LEDs 9-1, 9-2 by means of lines 21-1, 21-2 connected to the evaluation unit 7. It is possible, for example, for the evaluation unit 7 to be implemented on the circuit board 33.

The photodiode 11 of the detection channel 31 has an optical axis OA1 (double-dot-dashed line) which is perpendicular to the transport plane TE. The optical axis OA1 of the photodiode 11 defines the center of the area monitored by the photodiode 11 (viewing area). The sensitivity of the photodiode 11 is maximum along the optical axis OA1 of the photodiode 11. The window 39, that is to say the photodiode 11 (whose end facing the bank note 3) has a negligible thickness thereof, is arranged at a distance D1 (for example approximately 0.7 mm) from the transport plane TE. This means that the field of view of the photodiode 11 is (essentially) defined by the alignment of the optical axis OA1 of the photodiode 11, the distance D1 and the radial sensitivity distribution of the photodiode 11 with respect to the optical axis OA1 of photodiode 11. For example, the field of view is symmetrical to optical axis OA1 of photodiode 11.

The LEDs 9-1, 9-2 are arranged transversely to the transport direction TR to the left and right of the photodiode 11 and each have an associated optical axis OA2, OA3 which intersect the optical axis OA1 of the photodiode. The LEDs 9-1, 9-2 are thus inclined with respect to the transport plane TE. The optical axes OA2, OA3 of the LEDs 9-1, 9-2 define the axes of the greatest radiation intensity of the emitted IR radiation. For example, the IR radiation is emitted by the LEDs 9-1, 9-2 symmetrically to their optical axes OA2, OA3. The LEDs 9-1, 9-2 thus emit the IR radiation to a region of the bank note 3 which corresponds to the field of vision of the photodiode 11 (shown by the dashed lines).

The reflector 13 is arranged on the second flat side 3b of the bank note 3. The reflector 13 is aligned parallel to the transport plane TE, is arranged at a distance D2 from it (eg approximately 0.7 mm) and is cut by the optical axis OA1 of the photodiode 11. A small distance D2 increases the portion of the radiation which is reflected to the photodiode 11. The distances D1 and D2 can add up to a value of, for example, ≥ 1.4 mm, whereby D1 and D2 can have different values from one another. For example, it is possible for the reflector 13 to be designed as the bank note guide, at least in some areas. As for them Fig.1 described, the phosphorescent radiation of the security feature 3 ′ can be generated using the LEDs 9-1, 9-2 and the reflector 13 and reflected to the photodiode 11.

In the Fig. 2 the security feature 3 ′ is shown by way of example, which is offset with respect to the optical axis OA1 of the photodiode 11 transversely to the transport direction TR, that is, partially with the field of view of the photodiode 11 overlaps. The security feature 3 'thus receives the IR radiation emitted by the LEDs 9-1, 9-2 (LED 9-2: direct IR radiation; LED 9-1: direct and indirect (reflected on the reflector 13) IR radiation) and emits corresponding phosphorescence radiation, which is detected by the photodiode 11 (directly and indirectly (reflected on the reflector 13)).

The above-described arrangement of the LEDs 9-1, 9-2 and the photodiode 11 is only an example; it is for example possible that the optical axes OA1, OA2 and OA3 have different inclinations from one another and / or do not intersect. For example, an arrangement is possible in which the LEDs 9-1, 9-2 irradiate an area of the banknote 3, which is opposite to the transport direction TR outside the field of view of the photodiode 11, and this area due to the transport of the banknote 3 in the field of view of the Photodiode 11 is transported. That is to say, the security feature 3 ′ can be excited outside the field of view of the photodiode 11 and then transported into the field of view. Thus, the emitted radiation (which, for example, can also include other than the IR spectrum, for example through additional LEDs) can be emitted into a field of view of another sensor of the device 1 and used to detect other types of security features, for example one in the ultraviolet spectrum fluorescent security feature.

By transporting the bank note 3 under the detection channel 31, a strip (field of view of the photodiode 11) of the bank note 3 can be detected parallel to its short edges, the strip being checked for the presence of a security feature 3 '. If a security feature 3 'completely overlaps with the strip, a maximum signal (100%) is output by the detection channel. A partial overlap is considered to be reliably detectable if a signal is generated with a signal strength which corresponds to at least 50% of a maximum signal strength of the detection channel. For example, a low generated partially Overlapping of a security feature with a strip a signal with the strength of at least 50% of the maximum strength.

Since different bank notes 3 can be accepted by the device 1 with different orientations, the position at which a security feature 3 'occurs is unknown. To check the entire bank note 3, further detection channels are required, a plurality of strips to be checked being arranged next to one another transversely to the transport direction TR. This is in the Fig. 3 which shows a schematic arrangement of detection channels (first to eleventh detection channels 31-1 to 31-11) in the device 1 together with several possible positions of a bank note 3 in a plan view (the transport direction of the bank note 3 is upwards in the plane of the drawing) . The number of detection channels depends on the largest bank note that is accepted by the device 1: as many detection channels are provided as are required to be able to check the largest bank note along its long edge 3c, 3d.

In the embodiment of Fig. 3 A first and a second banknote 3-1, 3-2 with different sizes and differently positioned security features 3 'are shown as banknote 3 by way of example. The banknotes 3-1, 3-2 are two differently small banknotes with small security features 3 '(for example approximately 13 mm × 13 mm for the first banknote 3-1), whereby the detection of such a security feature is ensured is, even larger banknotes can be safely checked. The detection channels 31-1 to 31-11 correspond in function and structure to that in FIG Fig. 2 detection channel 31 described. The detection channels 31-1 to 31-11 monitor associated strips S1 to S11 within which the presence of a security feature 3 'can be determined. The bank notes 3-1, 3-2 are shown offset transversely to the transport direction TR at different positions P1 to P6: P1 to P3 for the first bank note 3-1 and P4 to P6 for the second banknote 3-2. In the positions shown, the banknotes 3-1, 3-2 are detected by the detection channels 31-1 to 31-11, the associated security features 3 'overlapping with the corresponding strips S1 to S7. Examples of an overlap with the strips S8 to S11 are not shown, but can also be obtained by turning the bank notes 3-1, 3-2 on their other flat side.

The first to eleventh detection channels 31-1 to 31-11 are arranged from left to right at a distance from one another which is set up to allow even the smallest security feature 3 '(first bank note 3-1) to be positioned in a most unfavorable position of the first bank note 3- 1 to be securely detected in the device 1 (for example first bank note 3-1 in position P3). In the example of Fig. 3 a maximum signal is generated for the strips S4 and S7 when the second bank note 3-2 moves under the detection channels 31-1 to 31-11 (by the security feature 3 'of the second bank note 3-2 at positions P4 and P5). Furthermore, the at least partial overlap of the security feature 3 'of the first banknote 3-1 with the strips S1 (position P1), S4 (position P2) and S2 (position P3) and the at least partial overlap of the security feature 3' of the second banknote 3 -2 with the strips S5 and S6 (positions P5 and P6) when the bank notes 3-1, 3-2 pass under the detection channels 31-1 to 31-11, a signal with at least 50% of the maximum signal strength is generated. Thus, in the example of Fig. 3 all security features 3 'are reliably recorded. For example, it is additionally possible to provide a further row of detection channels in the transport direction TR in front of or behind the detection channels 31-1 to 31-11, which with respect to the detection channels 31-1 to 31-11 in the direction transverse to the transport direction TR by, for example half the detection channel are offset, so that a (for example essentially) full-surface detection of the bank notes 3-1, 3-2 takes place. For example, in the Fig. 3 The arrangement shown ten further to the detection channels 31-1 to 31-11 offset detection channels can be used.

The Fig. 4 FIG. 11 shows a flow chart of a method for detecting a security feature of a bank note which is implemented by the in FIG Fig. 2 Device 1 described takes place. The method is carried out in a controlled manner by the evaluation unit 7.

As soon as the bank note 3 is input into the device 1, the bank note 3 is transported S100 through the device 1 by the transport device 5 at a predetermined transport speed (e.g. 1.8 m / s - 3.4 m / s). The transport speed can be preset or varied by the device 1, e.g. depending on the type of bank note (expected currency), e.g. using a characteristic field. For example, information about which currency is to be processed is transmitted by the bank machine to the device 1, and the device 1 selects the corresponding parameters, for example the transport speed, from a characteristic field for the corresponding currency.

Then, when the bank note 3 reaches the detection channel 31, the bank note is irradiated S200 with IR radiation for a predetermined period of time (e.g. in about 75 microseconds). The irradiation stimulates the phosphorescence of the security feature 3 'when it is in the irradiated area. The duration of the irradiation can be selected by the evaluation unit 7 as a function of the type of bank note 3, for example on the basis of a characteristic diagram. Whether the bank note 3 has reached the detection channel 31 can. e.g. determined by the evaluation unit 7 based on the input time and the transport speed.

After the irradiation (after the end of the irradiation), measurement values are recorded S300, which are output by the photodiode 11. This is done by the evaluation unit 7 for a predetermined period of time (for example approximately 400 microseconds). The detection period can be selected by the evaluation unit 7 as a function of the type of bank note 3, for example using a characteristic map. In the event that a security feature 3 'is irradiated, the measured values represent a typical course of the decay of phosphorescence (for example decrease in radiation intensity per unit of time). In the event that no security feature 3 'is irradiated, the measured values represent a typical system response of the measuring system (photodiode 11 and evaluation unit 7); this can be, for example, a constant signal (for example, at least essentially unchanged signal) or a return of the measuring system from a saturation state.

The evaluation unit 7 then generates a signal curve S400 from the measured values. The signal profile is formed as long as the bank note 3 is transported under the detection channel 31.

The evaluation unit 7 then determines whether a security feature 3 ′ of the bank note 3 is present S500. This is done by evaluating the signal curves, ie comparing the signal curves or sections of the signal curve which are present after the irradiation. For example, these are compared with a predetermined reference signal profile or compared with one another. The signal profiles are compared, for example, on the basis of a specific radiation intensity drop per time unit, which is characteristic of the presence of a security feature 3 '(or a combination of several security features). The reference signal curves can be stored in a database, for example for a bank note or a plurality of bank notes, for example in the evaluation unit 7. The reference signal curves can relate to a single security feature or a combination (for example, sequence) of several security features.

In the event that there is a signal curve within which the specific radiation intensity drop per unit of time is present, this signal curve corresponds to a reference signal curve for the detection of a bank note with a security feature. In addition, this signal course differs from a previous signal course or section thereof, in which no security feature is detected, by the specific radiation intensity drop per unit of time. If such a match with the reference signal profile or such a difference from the previous signal profile is determined by the evaluation unit 7, the detection of the security feature 3 'takes place. The evaluation unit 7 (for example implemented by means of one or more processors) thus clearly carries out a pattern comparison with a reference signal previously determined and stored for a respective security feature. If the evaluation unit 7 determines a correspondence (represented by a correspondence value or an error value) that is greater than a predefined threshold value, which can be specified or set, for example, by the manufacturer or by a user, then the evaluation unit 7 outputs, for example, a signal that indicates that the respective security feature of the banknote has been positively determined. Alternatively, the checking of the bank note for other security features can simply be continued or the bank note can only be accepted.

In the opposite case, in which such a signal course is not present, the evaluation unit 7 determines that no security feature 3 'of the bank note 3 was detected. The evaluation unit 7 can then, for example, carry out one of the following actions: issue a corresponding alarm signal, carry out a system restart and a renewed check of the banknote, control the device, dispense the banknote into a storage compartment, instruct the bank machine not to accept / dispense any more banknotes and / or assume a security state, or the like.

Claims (13)

1. Device (1) for verifying a machine-readable security feature (3') of a document of value (3; 3-1, 3-2), wherein the device (1) has:

   • a transport device (5) configured to transport the document of value (3; 3-1, 3-2) through the device (1) on a transport plane (TE) in a transport direction (TR), wherein a first flat side (3a) and a second flat side (3b), opposite said first flat side, of the document of value (3; 3-1, 3-2) extend parallel to the transport plane (TE),

   • a radiation emitter (9; 9-1, 9-2) that is arranged on the first flat side (3a) and is configured to emit at least infrared radiation in the direction towards the first flat side (3a), wherein the emitted radiation is configured to excite luminescent radiation of the security feature (3') of the document of value (3; 3-1, 3-2), and the emitted radiation is further configured to pass at least partly through the document of value (3),

   • a sensor (11) that is arranged on the first flat side (3a) and is configured to receive at least part of the luminescent radiation and of the emitted radiation,

   • a reflector (13) that is arranged and configured on the second flat side (3b) so as to reflect the emitted radiation, passing through the document of value (3; 3-1, 3-2), of the radiation emitter (9; 9-1, 9-2) and the luminescent radiation of the security feature (3') of the document of value (3; 3-1, 3-2) at least partly to the sensor (11), and

   • an evaluation unit (7) configured to control the radiation emitter (9; 9-1, 9-2) and to receive the signals output by the sensor (11),

   wherein the radiation emitter (9; 9-1, 9-2) has a first component radiation emitter (9-1) and a second component radiation emitter (9-2) and the sensor (11) is a photodiode, is tuned to the spectrum of the radiation emitter (9; 9-1, 9-2) and is arranged between the first component radiation emitter (9-1) and the second component radiation emitter (9-2) along a direction transverse to the transport direction.
2. Device (1) according to Claim 1,
   wherein the radiation emitter (9; 9-1, 9-2) is configured to emit the emitted infrared radiation in the near-infrared spectrum.
3. Device (1) according to Claim 1 or 2,
   wherein the radiation emitter (9; 9-1, 9-2) is an LED.
4. Device (1) according to one of the preceding claims,
   wherein the sensor (11) and the radiation emitter (9; 9-1, 9-2) are at least partly enclosed by a material (37) transparent to the luminescent radiation and the emitted infrared radiation and the radiation in the visible spectrum.
5. Device (1) according to one of the preceding claims,
   wherein the reflector (13) is arranged at a distance (D1) of a maximum of 10 mm from the flat side (3a) of the document of value (3; 3-1, 3-2).
6. Device (1) according to one of the preceding claims,
   wherein, when an optical axis (OA1) of the sensor (11) is perpendicular to the transport plane (TE), a distance (D2) of the sensor (11) from the flat side (3a) of the document of value (3; 3-1, 3-2) is 1 mm - 3 mm, preferably 1 mm - 2 mm and more preferably 1 mm.
7. Device (1) according to Claim 6,
   wherein a field of vision of the sensor (11) is configured such that a minimum dimension, able to be sensed by the sensor (11), of the security feature (3') of the document of value (3; 3-1, 3-2), transverse to the transport direction (TR), which is able to be sensed with respect to a maximum signal strength of the sensor (11) when sensing the security feature (3') with a signal strength of at least 50%, is 5 mm - 10 mm and preferably 6.5 mm - 7.5 mm.
8. Device (1) according to Claim 6 or 7,
   wherein an optical axis (OA2, OA3) of the radiation emitter (9-1, 9-2) is inclined with respect to the transport plane (TE) such that its point of intersection with the transport plane (TE) and the reflector (13) lies in the field of vision of the sensor (11).
9. Device (1) according to one of the preceding claims,
   wherein the sensor (11) interacts with the radiation emitter (9-1, 9-2) as a sensing channel (31; 31-1 - 31-11) that senses a strip (S1 - S11) of the document of value (3; 3-1, 3-2) in the transport direction (TR) when the document of value (3; 3-1, 3-2) is transported, and a plurality of sensing channels (31-1 - 31-11) are arranged next to one another transverse to the transport direction (TR) of the document of value (3; 3-1, 3-2).
10. Device (1) according to one of the preceding claims,
    wherein the document of value (3; 3-1, 3-2) is one of the following:

    • a banknote;

    • a cheque;

    • proof of identity;

    • a passport;

    • a travel ticket;

    • a share document.
11. Device (1) according to Claim 10,
    wherein the transport device (5) is configured such that the banknote (3; 3-1, 3-2) is able to be transported through the device (1) with one of its long edges (3c, 3d) at the front.
12. Method for verifying a machine-readable security feature of a document of value (3; 3-1, 3-2) using a device according to one of the preceding claims during transport thereof between a sensor (11) and a radiation emitter (9; 9-1, 9-2) on one side and a reflector (13) on the other side, wherein the method involves:

    • transporting (S100) the document of value (3; 3-1, 3-2) at a predetermined transport speed,

    • irradiating (S200) the document of value (3; 3-1, 3-2), by way of the radiation emitter (9; 9-1, 9-2), for a predetermined duration,

    • after the irradiation, sensing (S300), using the sensor (11), a plurality of measured values over a predetermined duration that corresponds to luminescent radiation of the security feature (3') that is excited by the irradiation, and/or to radiation reflected by the document of value (3; 3-1, 3-2) and/or by the reflector (13),

    • forming (S400) a signal profile from the measured values using an evaluation unit (7), and

    • evaluating (S500), using the evaluation unit (7), whether a security feature (3') is present by comparing the sensed signal profiles.
13. Method according to Claim 12,
    wherein the evaluation (S500) of the signal profiles reveals that a security feature (3') is present if a value formed in a subtraction of the signal profiles is greater than a reference value.

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