EP2304696A1

EP2304696A1 - Sensor device for the spectrally resolved capture of valuable documents and a corresponding method

Info

Publication number: EP2304696A1
Application number: EP09765540A
Authority: EP
Inventors: Michael Bloss; Martin Clara; Wolfgang Deckenbach
Original assignee: Giesecke and Devrient GmbH
Current assignee: Giesecke and Devrient Currency Technology GmbH
Priority date: 2008-06-17
Filing date: 2009-06-04
Publication date: 2011-04-06
Anticipated expiration: 2029-06-04
Also published as: RU2534946C2; CN102124497B; EP2304696B1; CN102124497A; WO2009152960A1; US8817242B2; RU2011101497A; ES2620679T3; DE102008028690A1; ES2620679T8; US20110102772A1

Abstract

The invention relates to a sensor device for the spectrally resolved capture of optical detection radiation that originates from a valuable document transported through a capture zone of the sensor device. The sensor device comprises a detection device for the spectrally resolved detection of the detection radiation and the emission of detection signals that reflect at least one property of the detection radiation, at least one reference radiation device emitting an optical reference radiation that is injected into a detection beam path of the detection device and that has a spectrum having a structure that lies within the spectral detection zone, and that has a radiation source which acts as a transmitter of a photoelectric barrier or of a light scanner by means of which a movement and/or a position of the valuable document in relation to the capture zone can be detected, and a control and evaluation device that is designed to receive detection signals of the detection device, to evaluate them and to emit evaluation signals depending on the result of evaluation and that is further designed to use detection signals that reflect the property of the reference radiation to examine and/or adjust the detection device and/or to make correction data available which can be used in the evaluation of detection signals that reflect at least one property of the detection radiation originating from the valuable document.

Description

Sensor device for the spectrally resolved detection of value documents and a method relating to them

The present invention relates to a sensor device for the spectrally resolved detection of optical detection radiation emanating from a transported by a detection range of the sensor device in a predetermined transport direction value document, and a method for detecting a movement and / or a position of the value document relative to the detection area the sensor device.

Under value documents are understood in the context of the invention sheet-shaped objects that represent, for example, a monetary value or a permission and therefore should not be arbitrarily produced by unauthorized persons. They therefore have features which are not easy to manufacture, in particular to be copied, whose presence is an indication of the authenticity, i. the manufacture by an authorized agency. Important examples of such value documents are coupons, vouchers, checks and in particular banknotes.

Due to their value, documents of value represent a not inconsiderable incentive for counterfeiting, ie the unauthorized production of documents with similar physical properties. In order to make such counterfeiting more difficult, value documents generally contain dyes that are difficult to obtain and / or only little known and / or luminescent substances which have a characteristic remission or luminescence spectrum. For checking a value document for authenticity or the presence of a counterfeit, optical radiation emanating from the value document can be obtained in the optical spectrum emitted by the characteristic part of the spectrum. Lumineszenzstoffs detected by a sensor device and compared with predetermined spectra. Such a check of the value documents can in particular be carried out by machine, wherein the value documents are transported through a detection range of the sensor device. The detection range is defined here and below by the fact that radiation coming from this area is detected and detected or measured by the sensor device. In the machine test, it is necessary to control the sensor device used so that it detects the properties of the document of value when it is in the detection area.

In such a machine test, the problem arises that the detection properties of the sensor device can change over time or during prolonged operation. In particular, for example, a shift of spectra to higher or lower wavelengths may occur, i. a spectral line in the spectrum of a given substance can be detected at a wavelength shifted from the actual wavelength corresponding to the spectral line. This behavior can affect the distinction between genuine and forged value documents. This disadvantage is aggravated by the fact that a corresponding shift is not recognized or not early enough.

It is therefore an object of the present invention to provide a sensor device for the spectrally resolved detection of optical detection radiation emanating from a value document transported through a detection range of the sensor device in a predetermined transport direction, in which a change in detection properties of the sensor device can be easily recognized and, preferably, such changes can be easily at least partially compensated. Furthermore, a corresponding method should be specified. The object is achieved by a sensor device for the spectrally resolved detection of optical detection radiation emanating from a value document transported through a detection range of the sensor device in a predetermined transport direction, comprising a detection device for the spectrally resolved detection of the detection radiation in at least one predetermined spectral detection range and delivery of detection signals which reflect at least one, in particular spectral, property of the detected detection radiation, at least one reference radiation device which emits optical reference radiation which is coupled at least partially into a detection beam path of the detection device and which forms a spectrum with a structure which is within the predetermined spectral detection range, in particular with at least one narrow band, which lies within the predetermined spectral detection range, and / or m it has at least one edge which is within the predetermined spectral detection range, and which has a radiation source which emits the reference radiation or whose radiation is used to generate the reference radiation and which acts as a transmitter of a light barrier or a light sensor, by means of which or a movement and / or a position of the value document relative to the detection range can be detected, and a control evaluation device, which is designed to receive detection signals of the detection device, evaluate and output evaluation signals depending on the result of the evaluation, and further is designed to detect signals that reflect the property of the reference radiation, for checking and / or matching the detection device and / or for providing correction data, in the evaluation of detection signals, the at least one property represent detection radiation emanating from the value document, are usable.

The sensor device is thus configured to detect spectrally resolved optical properties along a transport path in a predefined transport direction of transported value documents. In this case, the actual detection takes place by means of the detection device, which is designed for the spectrally resolved detection of optical radiation emanating from the value document in the spectral detection region, which is the detection radiation, for example, depending on properties of the value documents to be examined. A spectrally resolved detection is understood in particular to be a detection taking place over a continuous wavelength range or a detection taking place over a plurality, preferably more than eight, wavelength intervals. To generate the detection radiation, the value document can be illuminated, for example, with illumination radiation which, for example, is reflected more or less diffusely as detection radiation without changing the wavelength. With appropriate equipment of the value document with at least one luminescent feature, however, this can also be illuminated with illumination radiation, which excites the value document for emitting luminescence radiation, which then forms the detection radiation.

In this case, the detection radiation passes along the detection beam path from the detection area to a device of the detection device causing a spectral splitting, from which the spectral components reach at least one receiving or detection element of the detection device. The position of the detection area is at least given by the position and the design of the detection device. Of the The transport path and the direction of transport result, inter alia, from the position of the detection area, the requirement that a value document without lateral deflection in the area immediately before the detection area should enter it and, if the sensor device has several tracks, its location.

When a value document is transported along the transport path to the sensor device, the detection device can detect the detection radiation from at least one section of a value document that is located in the detection area.

The reference radiation device is used for emitting optical reference radiation, which is coupled into the detection beam path of the detection device and thus can be detected by this spectrally triggered. By optical radiation is meant radiation in the ultraviolet, visible or infrared spectral range. The coupling can be done at any point of the detection beam path, which still allows a spectral detection, but preferably the coupling is such that the reference radiation comes out of the detection range. The beam path of the reference radiation is largely determined by the reference radiation device, but may also be determined in part by the position of the value document. Depending on the embodiment of the reference radiation device and thus of the reference beam path, the coupling can take place either when there is no value document in the detection area or when a value document is in the detection area. In the first case, the reference radiation passes at least partially directly into the detection beam path; In particular, the reference beam path can lead directly into the detection beam path. In the second case, a remission of the reference radiation by a sensitive section of the value document done so that the remitted reference radiation enters the detection beam path.

To generate the reference radiation, the reference radiation device has a radiation source which either directly emits the reference radiation or whose radiation can be used to generate the reference radiation, for example by illuminating a fluorescent reference material with radiation from the radiation source.

Since the spectrum of the reference radiation lies at least partially within the spectral detection range of the detection device and thus of the sensor device and is predetermined or known, the reference radiation can be used to test at least one optical, in particular spectral, property of the sensor or detection device which Sensor or detection device to match and / or for providing data, in particular correction data, which are used in an evaluation of detection signals in the investigation of a value document serve.

For this purpose, the control and evaluation device connected to the detection device via at least one signal connection is provided which also undertakes the evaluation of the detection signals in the detection of optical detection radiation from a value document and output of corresponding evaluation signals. The control and evaluation device can, in principle, be constructed in any desired manner and, in particular, a processor, a memory in which a computer program is stored, in the execution of which the processor performs the function of the control and evaluation device, an application-specific integrated Circuit and / or a programmable gate array ", in particular particular a "field programmable gate array" (FPGA), or combinations of these components include.

The spectrum of the reference radiation is given by the formation of the reference radiation device, as will be explained in more detail. The control and evaluation device can use the detection signals directly or after conversion into data representing the property of the detection radiation.

The radiation source of the reference radiation device continues to serve as

Transmitter of a light barrier or of a light sensor, by means of which the movement and / or the position of the value document relative to the detection area can be detected, and the or so for controlling corresponding components of the sensor device, in particular the detection device and the control unit. and evaluation can be used. The radiation source therefore fulfills a dual function, namely that of a source for generating reference radiation or for reference radiation and that of a transmitter of a light barrier or a light sensor. A light barrier is understood here to mean a device which has a transmitter for emitting optical radiation along a light barrier beam path, a receiver for receiving radiation of the transmitter propagating along the light barrier beam path and output of corresponding received signals and an evaluation device connected at least to the receiver for evaluating reception signals of the receiver, whether optical radiation emitted by the transmitter is shielded by an object along the barrier beam path and does not reach or not reach the receiver. A light barrier therefore checks whether its beam path has been interrupted by an object. The light barrier can be designed as a reflection light barrier or a one-way light barrier be. In contrast, a light scanner has a transmitter for emitting optical radiation along a transmission beam path, a receiver for receiving optical radiation of the transmitter, which is remitted from the area of the transmission beam path of an object, and for outputting corresponding receiver signals and one connected to at least the receiver Evaluation device, which determines on the basis of the receiver signals, whether an object is in the transmission beam path and outputs a corresponding signal.

Due to the dual function of the radiation source, a simplified structure of the sensor device can be obtained.

The object is thus also achieved by detecting a movement and / or a position of the value document relative to a detection area of a sensor device for the spectrally resolved detection of optical detection radiation emanating from a value document transported through a detection area of the sensor device in a predetermined transport direction , wherein the sensor device has a detection device for the spectrally resolved detection of the detection radiation in at least one predetermined spectral detection range and emission of detection signals that reflect at least one, in particular spectral, property of the detected detection radiation, in which a value document along a transport path in the detection range of the sensor device is transported in a predetermined transport direction, optical radiation is generated, which is at least partially directed to the transport path of the document of value, so d It is suitable for detecting a movement and / or a position of the value document relative to the detection area, and which serves for the provision of reference radiation which enters a detection beam path of the detection device coupled and a spectrum with a narrow band, which is within the predetermined spectral detection range, and / or at least one spectrum with an edge, which lies within the predetermined spectral detection range, which is detected from the detection range reference radiation is detected to form detection signals , which reproduce the property of the reference radiation, and the detection signals for checking and / or matching the detection device and / or for providing correction data which, in the evaluation of detection signals, comprise the at least one property of detection radiation emanating from the value document are reproduced, usable, and the coming of the transport path optical radiation or coming from the detection range reference radiation is detected and for detecting the movement and / or the position of the document of value relative to the detection area or for detection whether and / or when a value document enters the coverage area and / or a value document is located at least partially in the coverage area.

In the context of the invention, the property of the reference radiation as well as the detection radiation in general is understood to mean a property that can be represented by at least one numerical value.

A test is understood to mean, on the one hand, that it is determined whether a value corresponding to the detected property of the reference radiation is within a predetermined tolerance interval. Depending on the result of the determination, a corresponding signal can then be generated. In the context of the invention, the term test on the other hand also means a calibration. A calibration is understood to mean that, given given conditions, a relationship or a deviation between a value of the reference radiation corresponding to the detected property and a predetermined, preferably known, value for the characteristic of the reference radiation, and to store the deviation or the context-representing data.

Adjustment, also known as adjustment, is understood as meaning a change in the sensor device, by which the deviation between a value corresponding to the detected property of the reference radiation and a predetermined, preferably known, value for the characteristic of the reference radiation is reduced as far as possible.

However, the detected property of the detection radiation can also be used in the sense of an adjustment of the sensor device to carry out a correction in the evaluation of detection signals. For this purpose, in the method of the detection signals for the reference radiation data, hereinafter also referred to as correction data can be determined, stored in a memory, for example in the control and evaluation, and later used in the evaluation of detection signals in the examination of value documents become. The determination of the data from the detection signals for the reference radiation can be done by means of the control and evaluation, which is designed accordingly.

By using the in particular narrow-band reference radiation or reference radiation with an edge in the spectrum, changes in the detection properties of the sensor device can be easily detected. The photocell or the light sensor must still have a receiver for the radiation of the radiation source. There are several options for this. According to a first alternative, optical radiation is used for the light barrier or the light sensor, which is not the reference radiation. For this purpose, the sensor device, as the receiver of the light barrier or of the light scanner, can have at least one detection element not belonging to the detection device for converting radiation from the radiation source into electrical reception signals which receive no detection radiation. This makes it possible to turn on the detection device only when a value document is actually in the detection area. In this alternative, the reference radiation can in principle be coupled into the detection beam path as desired, but preferably the coupling of the reference radiation into the detection beam path takes place as a function of the position of a value document relative to the detection region. This offers the advantage that the reference radiation coming from the detection area can be coupled into the detection beam path, so that ratios are used for the examination of the detection device, which correspond to those in the actual detection of the properties of a value document.

In another alternative, reference radiation is used as radiation for the light barrier or the light sensor. In a first preferred embodiment, the sensor device as a receiver of the light barrier or of the light scanner, at least one not belonging to the Detektionseinrich- detection element for converting reference radiation into electrical received signals having no detection radiation. In this embodiment too, in particular the coupling of the reference radiation into the detection beam path can be dependent on However, this is not absolutely necessary if the position of a value document relative to the coverage area is to be determined.

In the method, therefore, it is not possible to detect the movement and / or the position of the value document relative to the coverage area or to determine whether and / or when a value document enters the coverage area and / or a value document is located at least partially in the coverage area for the detection device belonging detection element, which receives no detection radiation, for converting the optical radiation or reference radiation into electrical received signals from which the position or movement of a value document can be determined is used and in which is determined from the received signals, if and / or when a value document enters the coverage area and / or a value document is located at least partially in the coverage area.

In a second embodiment of the other alternative, at least one section of the detection device serves as the receiver of the light barrier or the light sensor in the case of the sensor device. This makes it possible to keep the number of detection elements very low. In this case, in particular, the control and evaluation device can be further designed so that it determines from the detection signals of the detection device as received signals, if and / or when a value document enters the coverage area and / or a value document is at least partially in the detection area.

In accordance with the method, the reference radiation can then be coupled at least partially into the detection beam path as a function of the position of a value document relative to the detection area. the. In order to detect the movement and / or the position of the value document relative to the detection area from detection signals of the detection device which reproduce a property of the reference radiation, it can then be determined whether and / or when a value document enters the detection area and / or a value document is located at least partially in the detection area.

In particular, the reference radiation may be directed at least partially to the transport path of the value document, so that it is suitable for detecting a movement and / or a position of the value document relative to the detection area. Then, before the detection of the property of the reference radiation and / or for the subsequent detection of the spectral property of a value document, radiation formed by the reference radiation can be detected and used to detect the movement and / or the position of the value document relative to the detection area.

In all alternatives, in particular the sensor device may be associated with a transport path which is provided for transporting a value document along the transport direction into the detection area, and the optical radiation is emitted in the direction of the transport path, preferably as reference radiation. The radiation source can then emit its radiation, preferably the reference radiation, in the direction of the transport path. This allows a particularly simple construction of the light barrier or the light sensor.

A particularly accurate testing or calibration of the detection device or exact evaluation of the detection signals is made possible if in the sensor device the reference radiation device is designed so that the band of the reference radiation spectrum within the spectral Detection range has a width less than 5 nm. Accordingly, reference radiation is preferably used in the method, in whose spectrum the band within the spectral detection range has a width smaller than 5 nm. The width of the band is the full width at half maximum intensity ("Füll width at half maximum", FWHM).

In principle, any devices which emit optical radiation with the required spectrum can be used as reference radiation devices.

Thus, for example, the reference radiation can be formed by exciting with the optical radiation a luminescent sample for emitting reference radiation in the form of luminescence radiation. For this purpose, the reference radiation device can have a luminescent sample which can be excited by the optical radiation of the radiation source to emit reference radiation in the form of luminescence radiation. This embodiment has the advantage that no high demands on the radiation source need to be made.

Preferably, however, the radiation source of the reference radiation device can serve directly as a reference radiation source that emits the reference radiation, which, optionally after filtering, the spectrum with a narrow band that lies within the predetermined spectral detection range, and / or at least one spectrum with an edge, which is within the predetermined spectral detection range has. By the direct generation of the reference radiation in the reference radiation source, a very long-lasting stable generation of reference radiation of known properties can be achieved, which, when using As a result, the emission of luminescent substances as reference radiation is not necessarily the case. Also, contamination of the luminescing sample is not to be feared. By way of example, the reference radiation device can have a reference radiation source, preferably a light-emitting diode or a laser diode, and a narrow-band filter arranged downstream thereof for generating the narrow-band reference radiation. Accordingly, in the method, optical radiation whose spectrum lies at least partially within the spectral detection range can be generated, and the generated radiation can be narrowband filtered to form the reference radiation.

Furthermore, in the case of the sensor device the radiation source serves as a source for the reference radiation and as a source for the reference radiation a temperature-stabilized edge-emitting laser diode or a edge-emitting laser diode with a wavelength-selective optical resonator, in particular a resonator with high quality, can comprise. In the method, the reference radiation from at least one temperature-stabilized edge-emitting laser diode or an edge-emitting laser diode with a wavelength-selective optical resonator, in particular a resonator with high quality, can then be emitted. Basically, such facilities are known. A corresponding device is described in the patent application DE 102005040821 Al. When using the resonator, this has a natural frequency which corresponds to the desired wavelength of the reference radiation.

Alternatively, laser sources with distributed feedback, so-called DFR laser diodes, or laser diodes with distributed Bragg reflector, so-called DBR laser diodes, can be used as radiation sources for the reference radiation those persecuted The purpose is not to be equipped with a temperature stabilizer.

An even simpler alternative, however, is that in the sensor device, the radiation source serves as a source for the reference radiation and comprises at least one surface-emitting laser diode. In the method, the reference radiation is then preferably generated by means of at least one surface emitting laser diode. The use of such a laser diode offers several advantages. Thus, such laser diodes have a very narrow emission spectrum, so that preferably no filter or no reference substance is necessary between the reference radiation device and the detection device in order to limit the spectral bandwidth of the reference radiation. Further, the location of the tape is relatively insensitive to temperature effects as compared to laser diodes of another type, so that no temperature stabilization is necessary. In addition, the radiation emitted by surface emitting laser diodes is not very divergent. This has the advantage that in the sensor device preferably in the beam path after the surface emitting laser diode to the detection device no focusing optical element or luminescent substances need not be provided for generating the reference radiation and is not provided.

In principle, any desired properties of the detected reference radiation can be used. In particular, for the detection of spectra, however, it is preferred that a spectral property of the reference radiation is determined as a property of the reference radiation and used in the test or the comparison or the evaluation. For this purpose, the control and evaluation device can be further configured to determine a spectral property of the reference radiation as a property of the reference radiation and to be used for the evaluation, or for the comparison or the determination of the data for the evaluation. In particular, it can determine whether the detection signals which reproduce the spectral properties of the reference radiation, within a predetermined tolerance range with the known or predetermined corresponding properties of the reference radiation, as determined by the reference radiation device and possibly independently determined match. In particular, the position of a maximum of the spectrum or the center of gravity determined over a given wavelength range about the band or the edge can be used as the spectral property.

However, it is also possible, alternatively or in combination, to determine the intensity of the reference radiation as the property of the reference radiation and to use it for the evaluation during the test or the adjustment or the determination of the data. For this purpose, in the case of the sensor device, the control and evaluation device can be further configured to determine its intensity as a property of the reference radiation and to use it in the test or the adjustment or the evaluation. In this way, the sensitivity of the detection device can also be determined, for example, since in the evaluation of spectral properties the absolute intensity values in the spectral detection region need not necessarily be used.

In particular, when an adjustment is desired, in the sensor device, the detection device may have a spectrographic device with a detection element array and a spatially dispersing device spatially splitting detection radiation into spectral components falling on the detection element array, and the sensor device may further comprise at least one of the Control and evaluation device controllable actuator, which is mechanically with the detection element field, which is then movably mounted, or at least one movably mounted optical element of the spectrographic device, which determines the position of the spectral components on the detection element field at least partially, in particular a spatially dispersing device or an entrance slit, is coupled. The control and evaluation device is then designed to control the actuator as a function of the detection signals for the coupled reference radiation so that a deviation of a position of the spectral components of the reference radiation on the detection element field is reduced by a predetermined position.

The characteristics of the detection device may depend on a number of factors. For example, in the method, the temperature of at least part of the detection device and / or a part of a reference radiation device used for generating the reference radiation and / or a temperature compensation element connected to the detection device and / or the reference radiation device detected and in the test or the or Determining the data to be used for the evaluation. For this purpose, the sensor device can have at least one temperature sensor connected to the control and evaluation device via a signal connection for detecting the temperature of at least part of the detection device and / or a part of the reference radiation device and / or a temperature compensation element connected to the detection device and / or the reference radiation device ; the control and evaluation device can be further configured to also use the detected temperature during the test or the adjustment or the evaluation. In this way se can be a separation of various influences on the sensor device.

However, a temperature influence does not only have to occur in the detection device. In many embodiments, the sensor device may comprise an illumination device which, for detecting the spectral property of a value document outgoing detection radiation, for example luminescence radiation, emits optical illumination radiation into the detection area on a value document located therein, from which the detection radiation emanates. Then, the temperature of at least a part of the illumination device for illuminating the detection area and / or a temperature compensation element connected thereto can be detected and used for the evaluation or the determination of the data for the evaluation. The sensor device can then have an illumination device for illuminating at least part of the detection range and at least one temperature sensor connected to the control and evaluation device via a signal connection for detecting the temperature of at least part of the illumination radiation device and / or a temperature compensation element connected thereto; the control and evaluation device can be further configured to use the detected temperature in the test or the comparison or the evaluation. In this way, an influence of the illumination device can also be taken into account, but here the influence can not be determined by measurement using the reference radiation and the detection device.

The invention can be used in principle for any sensor devices of the type mentioned. Preferably, however, a detection device is used as detection device whose spectral Traler detection range has a width of less than 400 nm. Accordingly, in the sensor device, the detection means may be formed so that the spectral detection area has a width of less than 400 nm.

The detection device may comprise arbitrary, in particular also known, devices or elements for splitting into spectral components. In particular, the detection device may, for example, have a diffractive element dispersing in the prescribed spectral detection range. Examples of such elements are optical gratings, in particular also imaging gratings.

Alternatively or additionally, the detection device may have a refractive element dispersing in the predetermined spectral detection region. An example of such an element is a suitable prism.

The detection device can in principle have any desired reception or detection elements for detecting the spectrally separated components of the dispersing element, as long as they are sensitive in the necessary spectral range. Preferably, a spatially resolving CMOS, NMOS or CCD field is used to detect spectral components of the detection radiation and the reference radiation coupled into the detection beam path or the corresponding spectral components. The sensor device can accordingly have spatially resolving CMOS, NMOS or CCD field for the detection of spectral components of the detection radiation and the reference radiation coupled into the detection beam path. Such fields are easy and cheap available. Since the individual detection elements are read out one after the other in the case of CCD arrays, it can prove to be advantageous that, in particular for rapid detection, the detection device has an arrangement of individual detection elements whose signals can be read out independently of one another, preferably in parallel. Accordingly, in the method, an arrangement of individual detection elements whose signals are read out independently of each other, preferably in parallel, is used to detect the detection and reference radiation or their spectral components. This embodiment allows not only a fast reading, but also an adaptation of the sizes and properties of the individual detection elements according to the desired spectral sensitivity. Possibilities for this purpose are described, for example, in the application WO 2006/010537 A1 of the Applicant, the contents of which are hereby incorporated by reference into the description.

The reference radiation device can be designed and arranged such that the reference radiation is coupled into the detection beam path relative to the position of the value document as a function of the position of the value document. In particular, two possibilities are conceivable for this purpose. On the one hand, by appropriate design and arrangement of the reference radiation device, the reference radiation, possibly after deflection, from the detection area, ie like normal detection radiation when examining a value document, be coupled into the detection beam path. If a value document is located in the detection area, it shields the reference radiation and this can not be coupled into the detection beam path. For this purpose, for example, a source for the reference radiation with respect to a value document can be arranged in the detection area with respect to the detection device. However, it is also possible that the reference radiation source is related to a value document is arranged in the detection area on the same side as the detection device and has an optical element arranged on the opposite side and deflecting the reference radiation in the direction of the detection device. This alternative has the advantage that the reference radiation can be used directly.

On the other hand, it is possible that the reference radiation device is designed and arranged such that the reference radiation illuminates a value document located in the detection area and that the radiation emanating from the illuminated area, i. Reflected or reflected back from the value document reference radiation is coupled into the detection beam path. This alternative can be offered if, for reasons of space, the sensor device is to be arranged only on one side of the transport path.

The alternatives mentioned have the advantage that the reference radiation actually takes the same path as the detection radiation and thus a large proportion of possible sources for disturbances of the detection device is detected.

Furthermore, the control and evaluation device of the sensor device can evaluate the detection signals so that the detection of a movement and / or a position of the value document relative to the detection area before and / or after the determination of the at least one property of the reference radiation. The light barrier or the light sensor can thus be used to control the test or the adjustment of the sensor device or the determination of the data for evaluation. In particular, the method for checking and / or matching and / or determining the data for evaluation can be performed after each detection of a seizure of a Value document at or entering a value document into the coverage area. In this way, each value document can be checked with high quality, independently of the number of value documents checked in quick succession.

However, this light barrier or the light sensor can also be used in particular for controlling the detection of spectral properties.

Thus, as a function of the detected position or movement of the value document, the intensity of the reference radiation can be switched off or reduced for at least one predetermined period of time and / or as a function of the detection signals and then switched on or increased again. In the case of the sensor device, the control and evaluation device can be further configured for this, depending on the detected position or movement of the value document, the reference radiation device for at least a predetermined period of time and / or in response to detection signals of the detection device in a resting state and then again to turn into an operating state. Under the idle state is understood to be a state of the illumination device in which the optical illumination radiation is not emitted or with reduced intensity. In particular, the circuit can be in the idle state, preferably in dependence on the transport speed, after a predetermined time interval; the time interval can be chosen so that a later detection of the spectral property of the value document is not disturbed.

Furthermore, after a predetermined time interval after detection of an entry of a value document into the detection area, preferably for illuminating the value document in the detection area, optical processing can be carried out. irradiation radiation generated in a predetermined spectral illumination range with a predetermined minimum intensity and are radiated into the detection area and, preferably at the exit of the value document from the detection area, the optical illumination radiation switched off or its intensity can be reduced. In the case of the sensor device, the control and evaluation device can be designed for this purpose in such a way that after detecting a entry of a value document into the detection area after a predetermined time interval, an illumination device for illuminating the value document in the detection area with optical illumination radiation in a predetermined spectral illumination area Operating state switches, and preferably switches on exit of the value document from the detection area in an idle state. The predefined time interval may in particular be selected so that the property of the reference radiation can be detected during the time interval and / or a predetermined area of the value document can be detected with the sensor device after the time interval has expired. At least in the second case, the duration of the time interval can be selected as a function of the transport speed.

The invention will be further explained by way of example with reference to the drawings. Show it:

1 is a schematic view of a banknote sorting apparatus,

FIG. 2 shows a schematic illustration of a sensor device of the banknote sorting device in FIG. 1 with a section of a transport device, FIG. 3 is a schematic representation of a detection device of the sensor device in Fig. 2,

4 shows a schematic representation of a sensor device of a banknote sorting device according to a second embodiment with a

Section of a transport device,

5 shows a schematic representation of a sensor device of a banknote sorting device according to a third embodiment with a section of a transport device,

6 shows a schematic representation of a detection device of a sensor device of a banknote sorting device according to a fourth embodiment,

7 shows a schematic representation of a detection device of a sensor device of a banknote sorting device according to a fifth embodiment,

8 shows a schematic representation of a sensor device of a banknote sorting device according to a sixth embodiment,

9 shows a schematic representation of a sensor device of a banknote sorting device according to a seventh embodiment with a section of a transport device, and

10 shows a schematic representation of a sensor device of a banknote sorting device according to a further embodiment with a section of a transport device. A value-document processing device 10 in FIG. 1, which comprises a device for optically examining value documents 12, in the example of banknotes, has an input tray 14 for input of value documents 12 to be processed, a separator 16 which is located on value documents 12 in the input compartment 14, a transport device 18 with a switch 20, and along a given by the transport device 18 transport path 22 arranged in front of the switch 20 device 24 for examining documents of value, and after the switch 20, a first output tray 26 for recognized as real value documents and a second output tray 28 for value documents recognized as not genuine. A central control and evaluation device 30 is at least connected to the examination device 24 and the switch 20 via signal connections and serves to control the examination device 24, the evaluation of test signals of the examination device 24 and for controlling at least the switch 20 in dependence on the result of the evaluation test signals.

The examination device 24 in conjunction with the control and evaluation device 30 serves to detect optical properties of the value documents 12 and to form test signals representing these properties.

During the advance transport of a value document 12 at a predefined transport speed in a transport direction T predetermined by the transport path 22, the examination devices 24 detect optical property values of the value document, wherein the corresponding test signals are formed. From the test signals of the examination device 24, the central control and evaluation device 30 determines in a test signal evaluation, whether the value document is recognized as true according to a predetermined authenticity criterion for the test signals or not.

For this purpose, the central control and evaluation device 30 has, in addition to corresponding interfaces for the sensors, a processor 32 and a memory 34 connected to the processor 32 in which at least one computer program with program code is stored, in the execution of which the processor 32 controls or controls the device ., the test signals evaluates and corresponding to the evaluation, the transport device 18 controls.

In particular, the central control and evaluation device 30, and more precisely the processor 32 therein, can check a authenticity criterion, for example entering reference data for a value document to be regarded as authentic, which are predetermined and stored in the memory 34. Depending on the ascertained authenticity or non-authenticity, the central control and evaluation device 30, in particular the processor 32 therein, controls the transport device 18, more precisely the switch 20, so that the value document 12 can be filed according to its ascertained authenticity for storage in the first Output tray 26 is transported for recognized as real value documents or in the second storage compartment 28 for recognized as not real value documents.

The examination device 24 comprises a sensor device for the spectrally resolved detection of optical detection radiation emanating from a value document 12 transported in the predefined transport direction T. In the example, the detection radiation is luminescence radiation in the invisible region of the optical spectrum. The sensor device 24 designated below by the reference numeral 24 is shown in more detail in FIG. It comprises an illumination device 36 for illuminating at least part of a flat detection region 38 in the transport path 22, into which value documents 12 to be examined via the transport path 22 pass, and a detection device 40. A control device, in particular for controlling the illumination device 36, and an evaluation device, in particular for the processing and evaluation of detection signals of the detection device 40 are in a control and evaluation device 42, in the example of a programmed data processing device summarized, in this example a processor, not shown, and a memory, not shown, in which a program executable by the processor for Control of the illumination device 36 and the evaluation of the detection signals of the detection device 40 is stored includes. The control and evaluation device 42 is connected via a signal connection with the central control and evaluation device 30.

Further, a light sensor 44 is provided, which has a transmitter 46 and a receiver 48, which are connected to the control of the transmitter 46 and to the evaluation of signals of the receiver 48 to the control and evaluation device 42. In other embodiments, the evaluation of the signals of the receiver could also be done by a separate light scanner control, the output of which is then connected to the control and evaluation device 42.

The illumination device 36 is used to illuminate the detection area with optical radiation in a predetermined wavelength range, in this example in the infrared, and has to do so as a lighting radiation. tion source via a field of identically formed surface emitting laser diodes ("vertical cavity surface emitting laser diode", VCSEL), which are controlled in the example of the same by the control and evaluation device 42 via a corresponding signal connection. Radiation emitted by these laser diodes, hereinafter referred to as illumination radiation, is collected by a beam-bundling optics, not shown, of the illumination device 36 into a parallel beam.

To illuminate the detection region 38, the illumination radiation is directed by a deflection element 50 of the detection device 40, in the example a dichroic beam splitter, which is reflective for the illumination radiation, to a focusing optics 52, which focuses the illumination radiation onto the detection region 38. If there is a value document 12 in it, the section located in the detection area is illuminated with a corresponding illumination pattern.

Optical radiation excited by the illumination, in the case of a genuine value document 12 in the form of luminescence radiation, which lies within a spectral detection range predetermined by the type of value documents or the luminophore present therein, is emitted from the section and enters the region as detection radiation Detection beam path of the detection device 40th

The detection device 40 shown in greater detail in FIG. 3 for the exemplary embodiment serves for the spectrally resolved detection of the detection radiation in at least the predetermined spectral detection range and emission of detection signals which reproduce at least one, in particular spectral, property of the detected detection radiation. Such a detection device is more precisely described in the German patent avoiding the applicant with the official file reference 102006017256, the content of which is hereby incorporated by reference into the description.

In this embodiment, the detection device 40 for this purpose comprises detection optics 54, a spectrographic device 56 with a detection device 58 for the spectrally resolved detection of spectral components generated by the spectrographic device.

The detection optics 54 have along a detection beam path first the focusing optics 52, which images the detection area to infinity, i. from the detection range 38 coming detection radiation into a parallel beam, and the selectively transmissive deflection element 50, which is transparent for radiation in the predetermined spectral detection onsbereich. The detection optics 54 further comprises a condensing optics 60 for focusing the parallel detection radiation on an inlet opening or an entrance slit of the spectrographic device 56. Between the condensing optics 60 and the spectrographic device 56 are optionally a filter 62 for filtering unwanted spectral components from the detection beam path, in particular in the wavelength range of the illumination radiation, as well as a deflection element 64, in the example a mirror, for deflecting the detection radiation by a predetermined angle, in the example 90 °.

The spectrographic device 56 has an entrance aperture 66 with an aperture opening which is slit-shaped in the exemplary embodiment and which represents an entrance slit and whose longitudinal extent extends at least approximately orthogonally to the plane defined by the detection beam path. Detection radiation entering through the aperture is bundled into a parallel bundle by an achromatic collimation and focusing optics 68 of the spectrographic device 56 in the example. The collimating and focusing optics 68, like the other optics, are only symbolically represented as lenses in the figures, but in fact will often be embodied as a combination of lenses. Assuming that this optic is achromatic, it is understood that it is corrected for chromatic aberrations in the wavelength range in which the spectrographic device 56 operates. A corresponding correction in other wavelength ranges is not necessary. The entrance aperture 66 and the collimation and focusing optics 68 are arranged so that the aperture is at least in good approximation in the entrance aperture side focal surface of the collimating and focusing optics 68.

The spectrographic device 56 further includes a spatial dispersing device 70, in the example an optical reflection grating, which detects incident radiation, i. optical radiation coming from the detection area, at least partially decomposed into spectrally separated spectral components propagating in different directions in accordance with the wavelength.

The detection device 58 of the spectrographic device 56 has a detector arrangement 72, which serves for spatially resolving detection of the spectral components in at least one spatial direction. Detection signals formed by the detector arrangement are fed to the control and evaluation device 42, which detects the detection signals and, on the basis of the detection signals, performs a comparison of the detected spectrum with predetermined spectra. The tax and teeinrichtung 42 is connected to the control device 10 in order to transmit the result of the comparison via corresponding signals.

In the present example, the spatially dispersing device 70 is a reflection grating with a line structure whose lines run parallel to a plane through the longitudinal direction of the aperture opening and an optical axis of the collimating and focusing optics 68. The line spacing is chosen such that the detection radiation can be spectrally decomposed in the given spectral detection range, in the example in the infator. The dispersing device 70 is so aligned that the separate spectral components, in the example, the first diffraction order by the collimating and focusing optics 68 are focused on the detection means 58, more precisely the detector arrangement 72.

The detector array 72 has a line array of spectral component detection elements 74 at least approximately parallel to the direction of spatial separation of the spectral components, i. here the area spanned by the spectral components, in this case more precisely a plane, is aligned. In this case, the spectral components are imaged on the detector arrangement 72 by the collimation and focusing optics 68.

The cell-shaped detection elements 74 are formed so that their signals independently, preferably in parallel can be read out.

In order to achieve the most compact possible structure, on the one hand the dispersing device 70 is arranged in two directions with respect to the detector arrangement 72 and the direction of the incident detection radiation. see the collimating and focusing optics 68 and the dispersing device 70 inclined. In the exemplary embodiment, since the direction of the detection radiation between the collimating and focusing optics 68 and the dispersing device 70 extends parallel to the optical axis of the collimating and focusing optics 68, firstly the plane reflection grating 70 and thus also its line structure are opposite the optical one Axis O of the collimating and focusing optics 68 inclined in the plane of the detection beam path. Therefore, at least in the area between the dispersing device 70 and the collimating and focusing optics 68, the area produced by the spectral components, in the example a plane, is inclined by the angle α with respect to the direction of the detection radiation or the optical axis O of the collimating and focusing optics , In particular, a normal to the plane reflection grating 70 in the plane of the detection beam path by an angle α relative to the optical axis O of the collimating and focusing optics 68 is inclined (see Fig. 3). Second, the dispersing device 70, more precisely the specular reflection incidence slot, ie the normal to the plane of the line structure of the reflection grating 70, is an angle to the direction of the detection radiation or the optical axis O between the collimating and focusing optics 68 and the dispersing means 70 so that the first diffraction order is incident on the detector assembly 72.

On the other hand, the line of detection elements 74 of the detector arrangement is arranged at least approximately in a plane with the aperture of the entrance aperture 66 and in a direction orthogonal to the plane defined by the propagation directions of the spectral components away from the aperture, in FIG. 3 above the aperture. For the sake of clarity, FIG. 3 shows the entrance aperture 66 and the receiving surfaces of the detection elements 74 parallel to the focal plane. However, the collimating and focusing optics 68 are shown spaced apart, but in fact they are substantially in a common plane. As seen in the direction parallel to the line of detection elements 74, the aperture is approximately in the middle of the line.

During detection, therefore, detection radiation emanating from a point on the value document 12 in the detection area 38 is focused along the detection beam path by the focusing optics 52 into a parallel bundle which passes through the dichroic beam splitter and from the condensing optics 60 onto the entrance aperture 66 is shown. This is imaged along the detection beam path by the collimating and focusing optics 68 to infinity on the spatially dispersing device 70, which decomposes the radiation incident on them in spectral components. The spectral components of the first diffraction order are again imaged by the collimating and focusing optics 68 on the detector arrangement 72, wherein each detection element 74 corresponds to a wavelength or a wavelength range. A detection signal corresponding to the detection element reproduces in particular the intensity or power of the received spectral component. The detection device 40 outputs detection signals corresponding to the spectral properties of the detection radiation to the control and evaluation device 42. The detection signals are received and evaluated by the control and evaluation device 42.

The light sensor 44 has as a transmitter 46, a radiation source in the form of a surface emitting laser diode emitting optical reference radiation in a narrow wavelength range with a half-width (FWHM) of 1 nm, which is within the predetermined spectral detection range. For example, the maximum in the range of 760 nm, 808 nm, 948 nm or 980 nm. The transmitter 46 serves in this embodiment as a reference radiation device and reference radiation source. The laser diode 46 is directed onto the detection area 38 in such a way that, from a section of a value document 12 illuminated by it, a reflected reference radiation emitted in the detection area 38 passes into the detection beam path, ie is coupled in. The reflected portion of the reference radiation reaches the receiver 48, a photodetection element with an upstream diaphragm which is sensitive in the region of the reference radiation and outputs signals corresponding to reference radiation.

As is apparent from FIG. 2, reference radiation can only be coupled into the detection beam path and reach the receiver when a section of the value document 12 is located in the detection region 38. The coupling thus depends on the position of the value document 12 relative to the detection area 38.

The sensor device 24 operates as follows:

First, the light scanner 44, the lighting device 36 and the detection device 40 are turned off.

If the control and evaluation device 42 detects a signal of a transport sensor (not shown) on the transport path, which indicates the arrival of a transported value document 12, the control and evaluation device 42 puts the transmitter 46, ie the reference radiation device, into the operating state in which it is Reference radiation in the detection area 38 outputs. If the receiver 48 detects no reference radiation after a period of time has been selected as a function of the transport speed of the value documents, the control and evaluation device 42 switches the transmitter 46 back into the switched-off state.

However, if a value document 12 is transported as announced into the detection area, part of the reference radiation incident on the value document 12 is reflected in the direction of the receiver 48. If the receiver 48 detects reference radiation and outputs a corresponding signal to the control and evaluation device 42, it switches on the detection device 40 and detects its detection signals at least for the detection elements to which spectral components of the reference radiation should fall if they are set correctly to these neighboring detection elements.

Since the section of the value document 12 in the detection area 38 is illuminated by the reference radiation, this remitted, for example backscattered, reference radiation passes into the detection beam path and is decomposed into spectral components which are focused on the detector arrangement 72. This generates corresponding detection signals that reproduce or represent spectral properties of the reference radiation and outputs them to the control and evaluation device 42.

The control and evaluation device 42 receives the detection signals for a predetermined period of time, for example a period of time which is dependent on the transport speed, which is necessary for the detection of 1 mm of the value document, and determines whether the spectral property represented by the detection signals, at least one predetermined criterion is sufficient. In the example, she checks whether this is based on the tektionssignale detected maximum of the spectrum of the detection radiation within a predetermined tolerance range of the given by the surface emitting laser diode 46 maximum of the spectrum of the reference radiation. If this is not the case, an error signal is output.

Otherwise, the transmitter 46 is turned off. After a predetermined period of time, likewise selected as a function of the transport speed, in which detection signals for determining offset values are detected and the offset values are determined, the illumination device 36 is switched on and the spectral properties of the value document are detected. In this case, each of the detector elements of the detector arrangement is assigned a wavelength or a wavelength range.

After the expiry of a further period corresponding to the transport speed and the length of the longest of the expected value document in the transport direction, the illumination device 36 and the detection device 40 are switched off again.

A second exemplary embodiment, shown schematically in FIG. 4, of a sensor device 24 'differs from the first exemplary embodiment by the design of the light scanner and the control and evaluation device 42. All other parts are unchanged, so that the same reference numerals are used for them in the first embodiment and the explanations to these also apply accordingly.

In this embodiment, the detection device 40 assumes the role of the receiver of the light scanner. Instead of the light sensor 44, only one radiation trap 76 for a value document 12 in the detection area provided 38 reflected reference radiation, which absorbs corresponding reference radiation.

The control and evaluation device 42 'differs from the control and evaluation device 42 of the first embodiment only in that it controls the detection device 40 or evaluates their detection signals so that the detection device 40 operates as a receiver of the light scanner.

More specifically, it is designed to perform the following procedure.

If the control and evaluation device 42 'detects a signal of the transport sensor (not shown) on the transport path, which indicates the arrival of a transported document of value 12, the control and evaluation device 42' displaces the transmitter 46, i. the reference radiation device, in the operating state in which this reference radiation emits into the detection region 38, and the detection device 40 in its operating state, unless the detection device is operated anyway in continuous operation. From this point on, the control and evaluation device 42 'detects detection signals emitted by the detection device 40.

If the detection device 40 detects no reference radiation after a period of time selected as a function of the transport speed of the value documents and if the control and evaluation device 42 'accordingly detects no detection signals that are caused by the reference radiation, the control and evaluation device 42' displaces the transmitter 46 again in the off state and turns off the detection device. If, however, a value document 12 is transported into the detection area 38 as announced, the portion of the value document 12 located in the detection area is illuminated by the reference radiation. The reference radiation scattered by the illuminating section in the direction of the detection beam path is coupled into the detection beam path in the direction of the detection device 40 as a receiver, and decomposed into spectral components which are focused onto the detector arrangement 72. The detection device 40 generates corresponding detection signals that reproduce or represent spectral properties of the reference radiation and outputs them to the control and evaluation device 42 '. The control and evaluation device 42 'detects these detection signals and initially evaluates them only if any reference radiation has been detected, and optionally determines that an object has been detected by the light sensor.

The control and evaluation device 42 'receives the detection signals for a predetermined period of time, for example, a time interval selected as a function of the transport speed, which is necessary for the detection of 1 mm of the value document, and determines whether the spectral property represented by the detection signals, meets at least one predetermined criterion. In the example, it checks whether the maximum of the spectrum of the detection radiation determined on the basis of the detection signals is within a predetermined tolerance range of the maximum of the spectrum of the reference radiation given by the surface-emitting laser diode 46. If this is not the case, an error signal is output to the central control and evaluation device 30, which controls a display of a corresponding error message on a display, not shown. Otherwise, the transmitter 46 is turned off. The following steps are the same as those of the first embodiment.

A third exemplary embodiment of a sensor device 24 ", which is illustrated schematically in FIG. 5, differs from the second exemplary embodiment only in that a light barrier is used instead of a light scanner All other parts are unchanged, so that the same reference numerals are used for the same parts and the explanations to these also apply here.

As in the first two exemplary embodiments, the reference radiation device 46 "has as reference radiation source 78 the same surface-emitting laser diode and a deflecting element 80, in the example a mirror which deflects reference radiation emitted by the reference radiation source and couples it into the detection beam path if no document of value is present in the detection region 38 For this purpose, the deflection element is arranged on the side of the transport path opposite the detection device 40.

Apart from the modifications mentioned below, the control and evaluation device 42 "is designed in the same way as the control and evaluation device 42. In particular, it is designed to perform the following steps.

If the control and evaluation device 42 "detects a signal of the transport sensor (not shown) on the transport path, which indicates the arrival of a transported value document 12, the control and evaluation device 42 displaces the transmitter 46, ie the reference radiation device, into the operating state in which this reference radiation emits in the detection area 38, and the detection device 40 in its operating state, unless the detection device is operated anyway in continuous operation. From this point in time, the control and evaluation device 42 "detects detection signals emitted by the detection device 40.

As long as no value document 12 is located in the detection area 38, the reference radiation emitted by the laser diode 78 and deflected by the deflecting element 80 is coupled into the detection beam path and decomposed into spectral components which are focused on the detector arrangement 72. The detection device 40 generates corresponding detection signals that reproduce or represent spectral properties of the reference radiation and outputs them to the control and evaluation device 42 ".The control and evaluation device 42" detects these detection signals and determines whether the spectral characteristics represented by the detection signals Property satisfies at least one predetermined criterion. In the example, it checks whether the maximum of the spectrum of the detection radiation determined on the basis of the detection signals lies within a predetermined tolerance range of the maximum of the spectrum of the reference radiation given by the surface-emitting laser diode 78. If this is not the case, an error signal is output.

Otherwise, the detection of detection signals is continued. Only when a value document enters the detection area 38 is the optical path from the deflection element 80 to the detection device 40 interrupted. The control and evaluation device 42 "can no longer receive any detection signals which represent the spectral properties of the reference radiation and therefore constantly checks whether such signals are still present and, if these are no longer present, switches them on. Reference radiation source, in the example, the reference radiation source 78, from, since it detects an entry of the value document in the detection area 38.

After a predetermined period selected in dependence on the transport speed, in which detection signals for determining offset values are detected and the offset values are determined, the illumination device 36 is switched on and the spectral properties of the value document are detected as described in the first exemplary embodiment ,

After expiration of a further period of time corresponding to the transport speed and the length of the longest of the expected value documents in the transport direction, the illumination device 36 is switched off again and the reference radiation device 78 is switched on.

A fourth embodiment differs from the second embodiment in the design of the detection device shown in FIG. 6 and that of the control and evaluation device. All other parts are substantially unchanged from or analogous to the second embodiment, so that in each case the same reference numerals are used for such parts as in the second embodiment.

The detection device 82 differs from the detection device 40, inter alia, by using an imaging grating instead of the collimating and focusing optics 68 in conjunction with the reflection grating 70. Details of the detection device can be found in the application WO 2006/010537 A1 of the Applicant. entire content is hereby incorporated by reference into the description.

Like the detection device 40, the detection device 82 has the focusing optics 52, the deflecting element 50, the condenser optics 60, the filter 62 and the deflecting element 64, but somewhat rotated relative to the position in the first embodiment, which are all formed as in the first embodiment, therefore they are also used the same reference numerals as in the first embodiment.

A spectrographic device 84 of the detection device 82 in turn has an entrance aperture 66 formed as in the first exemplary embodiment, for which the same reference numeral as in the first exemplary embodiment is used. As the spatially dispersing device, an imaging grating 86 is used, which simultaneously spectrally dissects the detection radiation incident on it by diffraction and, since it is designed as a concave mirror, an image of the entrance slit formed by the entrance aperture 66 for at least some of the spectral components formed by it the detection radiation to a detection device 58 performs. The detection device 58 has a cell-shaped detector arrangement 88 of the spectrographic device 84 or the detection device 82, which is designed like the detector arrangement 72.

Furthermore, the detection device 82 has an adjustment device which makes it possible to change the position of the spectral components or the images of the entrance slit of the entrance aperture for the spectral components on the detector arrangement 88. On the one hand, for this purpose at least one suitable component of the spectrographic device is movable, preferably free of play, mounted.

On the other hand, the detection device 82 has an actuator (or a setting device) 90, which is mechanically coupled to the at least one component of the spectrographic device 84, in the example the spatially dispersing element 86, to the position of a predetermined by the spectrographic Device to change generated spectral component on the detector array. For this purpose, the actuator 90 is connected to the control and evaluation device via a signal connection and, in response to the actuating signals of the control and evaluation device, moves the at least one component of the spectrographic device, in the example the spatially dispersive element 86.

In the example, the actuator 90 has a piezoelectric element, which allows a very accurate movement of the component in response to appropriate control signals. Although theoretically a rotation of the imaging grating 86 to displace the position of the spectral components on the detector assembly 88 would be more favorable, in the present example the component is supported and the actuator 90 is mechanically coupled to the component such that the component is linearly moved in one direction which is orthogonal to the optical axis of the imaging grating and parallel to the splitting direction of the spectral components. This storage is much easier than a storage that allows pivoting.

The control and evaluation device 92 differs from the control and evaluation device 42 'in that it performs not only a check of the detection device 82, but also an adjustment. It is particularly adapted to carry out the following procedure. If the control and evaluation device 92 detects a signal of the transport sensor (not shown) on the transport path, which indicates the arrival of a transported document of value 12, the control and evaluation device 92 puts the transmitter 46, ie the reference radiation device into the operating state in which it is Reference radiation in the detection range 38 outputs, and the detection device 82 in its operating state, unless the detection device is operated anyway in continuous operation. From this point in time, the control and evaluation device 92 detects detection signals emitted by the detection device 82.

If the detection device 82 detects no reference radiation after a period of time selected as a function of the transport speed of the value documents and if the control and evaluation device 92 accordingly detects no detection signals that are caused by the reference radiation, the control and evaluation device 92 puts the transmitter 46 back in the off state and turns off the detection device.

However, if a value document 12 is transported as announced into the detection area, the portion of the value document 12 located in the detection area is illuminated by the reference radiation. The reference radiation scattered by the illuminating section in the direction of the detection beam path is coupled into the detection beam path in the direction of the detection device 82 as a receiver of the light scanner, and decomposed into spectral components which are focused on the detector arrangement 72. The detection device 82 generates corresponding detection signals which reproduce or display spectral properties of the reference radiation, and outputs these to the control and evaluation device 92. The Control and evaluation device 92 detects these detection signals and then evaluates them first if any reference radiation has been detected, and recognizes, if this is the case, that an object has been detected by the light scanner.

If an object, i. the value document is detected by the light sensor, the control and evaluation device 92 detects the following detection signals for a predetermined period of time, for example a selected depending on the transport speed period, which is necessary for the detection of 1 mm of the document of value, and determines a Deviation of the spectral characteristic represented by the detection signals from the spectral property predetermined for the reference radiation, which in the example is determined by the surface-emitting laser diode 46. In the example, it more precisely determines the difference between the wavelengths of the maximum of the spectrum of the detection radiation determined on the basis of the detection signals and the maximum of the spectrum of the reference radiation given by the surface-emitting laser diode 46. It does not necessarily have to determine the wavelengths explicitly, but it is also possible to form only differences between the detected position of the maximum on the detector array 88 and the predetermined position of the maximum on the detector array.

Depending on the difference determined, it now controls the actuator 90 in such a way that it moves the component, here the dispersing element 86, so that the difference is reduced. For example, the amount of displacement can be selected proportional to the difference or read out of a table in which the necessary shifts or control signals for predetermined differences are stored. Such a table can be determined by experiments or calculations. This results in an adjustment of the detection device.

Although there is only one control for a single document of value, a result corresponding to regulation of the detection device can be obtained when examining a plurality of rapidly successive documents of value, since the influences which cause undesired dejurition change only much more slowly ,

The following steps, i. the offset detection and the detection of the detection signals, which represent spectral properties of the luminescence radiation, correspond to those of the first exemplary embodiment.

In another variant, instead of the adjustment of the dispersing element, an adjustment of the entrance aperture 66, more precisely of the entry gap, can take place.

In yet another variant, at least one component of the spectrographic device is not moved, but the detector arrangement 88 is mounted linearly movable along its longitudinal direction and coupled to a corresponding actuator for moving the detector arrangement.

A corresponding adjustability of the spectrographic device can also be transferred to the other exemplary embodiments.

A fifth exemplary embodiment in FIG. 7 differs from the fourth exemplary embodiment in that the imaging grating is held firmly and the actuator 90 is omitted, and secondly by the formation of the detection device 58, ie the detector arrangement 72 or the detector Detector arrangement 88. Next, the control and evaluation device compared to the fourth embodiment is modified. The same reference numerals are used for the components that are unchanged from the fourth exemplary embodiment as in the fourth exemplary embodiment, and the explanations on these also apply correspondingly.

The detector array 88 'comprises a cell-shaped CCD array extending in its longitudinal direction parallel to the direction of spatial splitting of the spectral components. The CCD array provides high spatial resolution, in the example the CCD line array 256 includes detector elements arranged in a row.

The control and evaluation device is now designed to determine correction data that can be used for a correction of detected detection results. This is comparable to an adjustment of the sensor device.

In particular, the control and evaluation device 92 'is designed to carry out the following method.

If the control and evaluation device 92 'detects a signal of the transport sensor, not shown, at the transport path, which indicates the arrival of a transported document of value 12, the control and evaluation device 92' places the transmitter 46, ie the reference radiation device, in the operating state in which it is Reference radiation in the detection range 38 outputs, and the detection device 82 'in its operating state, unless the detection device is operated anyway in continuous operation. From this point in time, the control and evaluation device 92 'detects detection signals output by the detection device 82'. If the detection device 82 'detects no reference radiation after a period of time selected as a function of the transport speed of the value documents and the control and evaluation device 92' accordingly detects no detection signals which are caused by the reference radiation, the control and evaluation device 92 'displaces the transmitter 46 again in the off state and turns off the detection device 92 'from.

If, however, a value document 12 is transported into the detection area 38 as announced, the portion of the value document 12 located in the detection area 38 is illuminated by the reference radiation. The reference radiation scattered by the illuminating section in the direction of the detection beam path is coupled into the detection beam path in the direction of the detection device 82 'as a receiver, and in FIG

Spectral components that are focused on the detection device 58 and the detector array 88 '. The detection device 82 'generates corresponding detection signals which reproduce or display spectral properties of the reference radiation and outputs them to the control and evaluation device 92. The control and evaluation device 92 detects these detection signals and initially evaluates them only if any reference radiation has been detected, and if necessary determines that an object has been detected by the light sensor.

If an object, ie the document of value has been detected by the light sensor, the control and evaluation device 92 'detects the following detection signals for a predetermined period of time, for example a period selected as a function of the transport speed, which is necessary for the detection of 1 mm of the document of value. continue and determine one Deviation of the spectral characteristic represented by the detection signals from the spectral property predetermined for the reference radiation, which in the example is determined by the surface-emitting laser diode 46. In the example, it determines more precisely based on the detection signals for the reference radiation, the detection element, which has detected the maximum intensity, ie the maximum of the spectrum. This is implicitly a determination of an actual position of the maximum on a wavelength scale. It then stores the position of the maximum or the deviation of the position of the maximum from the desired position of the maximum with perfect setting of the detection device 82 'representing correction data.

Alternatively, it could also determine the wavelength of the maximum and the deviation from the predetermined wavelength of the maximum and store corresponding correction data.

The following step of the offset determination is carried out as in the first embodiment.

The illumination device 36 is then switched on and the spectral properties of the value document are detected. In this case, each of the detection elements of the detector arrangement is assigned a wavelength or a wavelength range. In the implementation of the detection signals in wavelengths, a correction of the detected spectrum according to a shift in the wavelength dependence is now performed, depending on the variant, using the correction data. This can be done, for example, by virtue of the fact that a corrected wavelength or a corrected wavelength range is assigned to each of the detection elements in accordance with the determined deviation or according to the correction data. is ordered. The resulting data can then be compared with given spectra of real value documents.

Alternatively, the predefined spectra could also be shifted using the correction data, after an implementation of the detection signals in intensities as a function of the wavelength or of the wavelength range has taken place.

After expiry of a further period of time corresponding to the transport speed and the length of the longest of the expected value documents in the transport direction, the control and evaluation device 92 'switches off the illumination device 36 and the detection device 40 again.

A sixth exemplary embodiment in FIG. 8 differs from the first exemplary embodiment in that temperature sensors 96 and 98, respectively, which are arranged on the illumination device 36 and a temperature compensation element 94 of the detection device 40, which is intended to dissipate heat from the optical components and the detector arrangement, are arranged Temperature of the illumination device 36 and the Temperaturausgleichsele- element 94 and thus the detection device 40 detect and deliver corresponding temperature signals to the connected to the temperature sensors via Signallei- ments control and evaluation device 100.

The control and evaluation device 100 is a combination of the control and evaluation devices of the first and fifth embodiments. With regard to the function of the light scanner, it is like the control and evaluation device 40 of the first embodiment and with respect to the determination and storage of correction data and their use. fertil like those of the fifth embodiment. The control and evaluation device 100 is furthermore designed to detect the temperature signals of the temperature sensors 96 and 98 and to use them in the determination of the correction data as well as the determination of the spectral properties of detection signals for detection radiation from a value document illuminated by the illumination device 36 , For this purpose, the effects of the temperature changes in the form of temperature correction data, which can be obtained by experiments or by using models for the illumination device and the detection device, are stored in the control and evaluation device 100.

A seventh exemplary embodiment in FIG. 9 differs from the first exemplary embodiment only in that, in the case of the sensor device 24 '", the illumination radiation is radiated obliquely onto the value document and the detection radiation is correspondingly detected obliquely.

Further exemplary embodiments differ from the first exemplary embodiment in that a temperature-stabilized edge-emitting laser diode, a DFR or a DBR laser diode or an edge-emitting laser diode with a high-quality optical resonator instead of the surface-emitting laser diode is used as the radiation source Causes reference radiation wavelengths includes.

Another embodiment in Fig. 10 differs from the first embodiment only in that the reference radiation is generated indirectly. Instead of the transmitter 46, a laser diode 102 is used whose optical radiation is incident on a beam path below the detection rich falls in the predetermined wavelength range of the reference radiation luminescent sample 104. This optical radiation of the laser diode is selected so that it can excite the sample 104 for emitting luminescence radiation as reference radiation in the above-mentioned sense, which is then coupled into the detection beam path.

In further exemplary embodiments, the control and evaluation device is modified in such a way that, in addition to the spectral characteristic of the reference radiation, it also determines its overall intensity and uses it in the checking, adjustment or determination of correction data.

In other exemplary embodiments, it is also possible to use a detection device as described in WO 01/88846 A1, which uses inter alia a two-dimensional CCD field as the detector arrangement.

Although in the embodiments shown, the reference beam path and the detection beam path at least partially parallel to the same plane or in the same plane, this need not be the case. For example, in the first exemplary embodiment it is also conceivable that the plane determined by the light scanner 44 and its beam path is orthogonal to the plane of the detection beam path of the illumination and sensor device shown in FIG.

Claims

Patent claims

1. Sensor device for the spectrally resolved detection of optical detection radiation emanating from a transported through a detection range of the sensor device in a predetermined transport direction value document comprising

a detection device for the spectrally resolved detection of the detection radiation in at least one predetermined spectral detection area and delivery of detection signals which reflect at least one, in particular spectral, property of the detected detection radiation,

at least one reference radiation device which emits optical reference radiation, which is coupled into at least one detection beam path of the detection device and which has a spectrum with a

Structure which is within the predetermined spectral detection range, in particular with at least one narrow band which lies within the predetermined spectral detection range, and / or with at least one edge which lies within the predetermined spectral detection range, and which has a radiation source which emits the reference radiation or whose radiation is used to generate the reference radiation and which acts as a transmitter of a light barrier or a light sensor, by means of which a movement and / or a position of the value document relative to the detection range can be detected, and

a control evaluation device, which is designed to receive detection signals of the detection device, to evaluate and output evaluation signals as a function of the result of the evaluation, and which is further configured to generate detection signals, which are the Property of the reference radiation, for checking and / or matching the detection device and / or for providing correction data which can be used in the evaluation of detection signals which reproduce the at least one property of detection radiation emanating from the value document.

2. Sensor device according to claim 1, further comprising as a receiver of the light barrier or the light sensor, at least one not belonging to the detection device detection element for converting radiation of the radiation source into electrical received signals, the no

Detection radiation receives.

3. Sensor device according to claim 1 or 2, wherein the coupling of the reference radiation in the detection beam path in dependence on the position of a value document relative to the detection area.

4. Sensor device according to one of the preceding claims, which further as a receiver of the light barrier or the light sensor, at least one not belonging to the detection device detection element for the implementation of reference radiation in electrical received signals, which receives no detection radiation.

5. Sensor device according to one of claims 1 or 3, wherein at least a portion of the detection device serves as a receiver of the light barrier or the light sensor.

6. Sensor device according to claim 5, wherein the control and evaluation device is further configured so that it determines from the detection signals of the detection device as received signals, whether and / or when a value document enters the coverage area and / or a value document is located at least partially in the coverage area.

7. Sensor device according to one of the preceding claims, wherein the reference radiation means is formed so that the band of the reference radiation spectrum within the spectral detection range has a width of less than 5 nm.

8. Sensor device according to one of the preceding claims, wherein the reference radiation means comprises a luminescent sample which can be excited by the optical radiation of the radiation source for emitting reference radiation in the form of luminescence radiation.

9. Sensor device according to one of the preceding claims, wherein the radiation source serves as a source for the reference radiation and a surface emitting laser diode, a DFR laser diode or a DBR laser diode comprises, and preferably in the beam path after the surface emitting laser diode or the DFR laser diode or the DBR laser diode is provided with no focusing optical element up to the detection device.

10. Sensor device according to one of the preceding claims, wherein the radiation source serves as a source for the reference radiation and comprises a temperature-stabilized edge-emitting laser diode or an edge-emitting laser diode with a wavelength-selective optical resonator.

11. Sensor device according to one of the preceding claims, wherein the control and evaluation device is further adapted to determine a property of the reference radiation, a spectral property of the reference radiation and to use in the test or the comparison or the evaluation.

12. Sensor device according to one of the preceding claims, wherein the control and evaluation device is further adapted to determine the property of the reference radiation whose intensity and to use in the test or the adjustment or the evaluation.

13. Sensor device according to one of the preceding claims, the at least one connected via a signal connection with the control and evaluation temperature sensor for detecting the temperature of at least a portion of the detection device and / or a

Part of the reference radiation device and / or associated with the detection device and / or the reference radiation device temperature compensation element, and in which the control and evaluation further designed to use in the test or the comparison or the evaluation of the detected temperature.

14. Sensor device according to one of the preceding claims, at least one connected via a signal connection to the control and evaluation device temperature sensor for detecting the temperature of at least a portion of the radiation source and / or associated with this temperature compensation element, and wherein the control and Evaluation device further trained to be involved in the tion or the evaluation or the evaluation to use the detected temperature.

15. Sensor device according to one of the preceding claims, wherein the detection device is formed so that the spectral detection onsbereich has a width of less than 400 nm.

16. Sensor device according to one of the preceding claims, wherein the detection device comprises a spatially resolving CMOS, NMOS or CCD field.

17. Sensor device according to one of the preceding claims, wherein the detection device comprises an array of individual detection elements whose signals are independently readable, preferably in parallel.

18. Sensor device according to one of the preceding claims, wherein the control and evaluation device is further adapted, depending on the detected position or movement of the value document, the reference radiation means for at least one predetermined

Period and / or depending on detection signals of the detection device in an idle state and then turn back to an operating state.

19. Sensor device according to one of the preceding claims, in which the control and evaluation device recognizes an entry of a value document into the detection area after a predetermined time interval, an illumination device for illuminating the value document in the detection area with optical illumination radiation in a predetermined spectral illumination range switches to an operating state, and preferably switches on exit of the value document from the detection area in an idle state.

20. A method for detecting a movement and / or a position of the value document relative to a detection range of a sensor device for spectrally resolved detection of optical detection radiation emanating from a transported through a detection range of the sensor device in a predetermined transport direction value document, wherein the sensor device comprises a detection device for spectrally resolved detection of the detection radiation in at least one predetermined spectral detection range and delivery of detection signals which reflect at least one, in particular spectral, property of the detected detection radiation, wherein: a value document along a transport path into the detection range of the sensor device in a predetermined transport direction is transported,

- Optical radiation is generated, which is at least partially directed to the transport path of the document of value, so that they are for detecting a movement and / or a position of the value document relative to the

Detection range is suitable, and which serves to provide reference radiation, which is coupled into a detection beam path of the detection device and a spectrum with a narrow band that lies within the predetermined spectral detection range, and / or at least one spectrum with an edge within the given Spectral detection range is located,

- The reference radiation coming from the detection area is detected to form detection signals that reflect the property of the reference radiation, and the detection signals for testing and / or for matching the detection device and / or for providing correction data that can be used in the evaluation of detection signals that reproduce the at least one property of detection radiation emanating from the value document, and

the optical radiation coming from the transport path or reference radiation coming from the detection area is detected and for detecting the movement and / or the position of the value document relative to the detection area or for determining whether and / or when a value document enters the detection area and / or yourself

Value document at least partially located in the detection area is used.

21. The method of claim 20, wherein for detecting the movement and / or the position of the value document relative to the coverage area or for determining whether and / or when a value document enters the coverage area and / or a value document at least partially in the detection area is, a not belonging to the detection means detection element which receives no detection radiation, for converting the optical radiation or reference radiation into electrical received signals from which the position or movement of a value document can be determined, is used and in which is determined from the received signals, if and / or when a value document enters the coverage area and / or a value document is located at least partially in the coverage area.

22. Method according to claim 20 or 21, in which the reference radiation is determined in dependence on the position of a value document relative to the detection at least partially coupled into the detection beam path.

23. The method according to claim 20, wherein for detecting the movement and / or the position of the value document relative to the detection area from detection signals of the detection device that reproduce a property of the reference radiation, it is determined whether and / or when a value document enters the coverage area and / or a value document is located at least partially in the coverage area.

24. The method according to any one of claims 20 to 23, is used in the reference radiation in the spectrum of the band within the spectral detection range has a width smaller than 5 nm.

25. The method according to any one of claims 20 to 24, wherein the reference radiation is generated by means of at least one surface emitting laser diode or at least one DFR laser diode or at least one DBR laser diode and preferably in the beam path after the surface emitting laser diode or the DFR laser diode or the DBR

Laser diode to the detection device no focusing optical element is provided.

26. The method of claim 20, wherein the reference radiation is generated by means of at least one temperature-stabilized edge-emitting laser diode or an edge-emitting laser diode with a wavelength-selective optical resonator.

27. Method according to claim 20, in which a spectral property of the reference radiation is determined as a property of the reference radiation and used for the evaluation in the test or the adjustment or the determination of the data.

28. The method according to any one of claims 20 to 27, wherein the property of the reference radiation, the intensity of the reference radiation is determined and used in the examination or the comparison or the determination of the data for the evaluation.

29. Method according to claim 20, wherein the temperature of at least part of the detection device and / or a part of a reference radiation device used for generating the reference radiation and / or a temperature compensation element connected to the detection device and / or the reference radiation device is detected and at the Check or the comparison or the determination of the data is used for the evaluation.

30. The method according to any one of claims 20 to 29, wherein the temperature of at least a portion of a lighting device for illuminating the detection area and / or a temperature compensation element associated therewith detected and in the examination or the comparison or the determination of the data for the evaluation is used.

31. The method according to any one of claims 20 to 30, wherein the detection device is a detection device is used whose spectral detection range has a width of less than 400 ran.

32. Method according to claim 20, wherein a spatially resolving CMOS, NMOS or CCD field is used to detect spectral components of the detection radiation and the reference radiation coupled into the detection beam path.

33. The method according to any one of claims 20 to 32, wherein for the detection of the detection and reference radiation, an arrangement of individual detection elements is used whose signals are read independently of each other, preferably in parallel.

34. The method according to claim 20, wherein the detection signals are evaluated in such a way that the detection of a movement and / or a position of the value document relative to the detection area before and / or after the determination of the at least one property the reference radiation takes place.

35. The method according to any one of claims 20 to 34, in which, depending on the detected position or movement of the document of value, the intensity of the reference radiation for at least a predetermined period and / or depending on the detection signals off or reduced and then switched on again or is increased.

36. The method according to claim 20, wherein after a predetermined time interval after recognition of an entry of a value document into the detection area for illuminating the value document in the detection area optical illumination radiation in a predetermined spectral illumination range with a predetermined minimum intensity generated and in the Area of coverage, and preferably upon withdrawal of the value document from the rich the optical illumination radiation switched off or their intensity is reduced.