EP3329473B1 - Aparatus and method for inspecting value documents and/or the transport of value documents using ultrasound - Google Patents

Description

The present invention relates to a device and a method for examining documents of value and / or the transport of documents of value by means of ultrasound.

In this context, documents of value are understood to be card-shaped or preferably sheet-shaped objects which, for example, represent a monetary value or an authorization and should therefore not be able to be produced by unauthorized persons at will. They therefore do not have features that are easy to produce, in particular to be copied, whose presence is an indication of authenticity, i.e. production by an authorized body. Important examples of such documents of value are chip cards, coupons, vouchers, checks and, in particular, bank notes.

Such documents of value are often processed by machine, for which purpose they are usually first separated from a stack and then separated, ie transported individually, along a transport path. Ultrasound, for example, can be used to examine the documents of value with regard to their condition and / or their authenticity and to examine certain aspects of the processing, in particular the transport. In the context of the present invention, the examination of the transport is understood to mean determining whether documents of value are transported individually and not overlapping and / or how they are oriented relative to their transport direction during transport and / or whether or at what points in time they reach a predetermined location of the transport path with a front edge in the transport direction or a rear edge in the transport direction. In the prior art, ultrasonic sensors that have one or more piezoelectric ultrasonic transducers are used for the investigation. The ultrasonic transducers use to generate ultrasound is a piezoelectric element that is excited to mechanical vibrations by a transmission signal in the form of an electrical alternating voltage. To receive ultrasound, a voltage that occurs when pressure is exerted on the piezoelectric element is recorded and evaluated.

However, these piezoelectric ultrasonic transducers have to be produced individually and assembled into a sensor, which is relatively expensive. In addition, such ultrasonic transducers are relatively sluggish. Accordingly, the spatial resolution that can be achieved is not always as good as would be desirable.

In DE 10 2013 015 224 A1 describes a method for checking a value document of a predetermined value document type for the presence of at least one irregularity of at least one predetermined type, for example an irregularity in the form of at least one adhesion, preferably an adhesive strip, and / or a fold and / or a material removal. In the method, an ultrasound data set is recorded which describes at least one ultrasound property, preferably the ultrasound transmission, of the value document in a spatially resolved manner, and a deviation data set is determined which describes a spatially resolved deviation between the ultrasound data set and a model and is determined in such a way that the deviation described by it is minimal with respect to the model, the model comprising a model for the location dependency of the at least one ultrasonic property of reference value documents of the specified value document type without irregularities of the at least one specified type. Using the deviation data record, it is checked whether there is an indication of an irregularity of the at least one type on the value document. Means for carrying out the method are also described.

In US 2014/010388 A1 describes a capacitive transducer with broadband frequency characteristics. The capacitive converter includes an element that has multiple types of cells. Each cell comprises: a first electrode, a vibrating layer having a second electrode, the second electrode facing the first electrode with a gap, and a support portion that supports the vibrating film to form the gap. The plural kinds of cells have different ratios of an area of one of the first electrode and the second electrode to an area of the gap when viewed in a direction normal to the vibrating film. The first electrodes or the second electrodes in the plurality of types of cells are electrically connected to each other.

The present invention is therefore based on the object of specifying a device for examining documents of value and / or the transport of documents of value by means of ultrasound, which is easy to produce and / or allows good examination of documents of value. A method for examining documents of value and / or the transport of documents of value by means of ultrasound is also to be specified, which allows a good examination of documents of value.

The object is achieved by a device with the features of claim 1 and in particular a device for examining documents of value and / or the transport of documents of value that are transported along a predetermined transport path in a predetermined transport direction, using ultrasound in a direction transverse to the transport direction staggered ultrasonic transmitters for emitting ultrasound onto the transport path for transmission signals and ultrasonic receivers arranged offset in a direction transverse to the transport direction for receiving ultrasound generated by the ultrasonic transmitter and for the delivery of received signals or with ultrasound transmitters / receivers arranged offset in a direction transverse to the transport direction for the delivery of ultrasound to the transport path in response to transmission signals and for receiving the ultrasound after interaction with at least one of the value documents and delivery of received signals. The ultrasonic transmitters and / or ultrasonic receivers each have at least one capacitive, micromechanical ultrasonic transducer or the ultrasonic transmitters / receivers each have at least one capacitive, micromechanical ultrasonic transducer.

The object is therefore further achieved by a method with the features of claim 19 and in particular a method for examining documents of value and / or transporting documents of value by means of ultrasound, in which ultrasound is applied to a document of value transported along a transport path by means of at least one ultrasonic transmitter in response to transmission signals and the ultrasound emanating from the document of value is then received by means of at least one ultrasound receiver and received signals are generated, or by means of at least one ultrasound transmitter / receiver, ultrasound is emitted onto a document of value transported along a transport path by means of at least one ultrasound transmitter / receiver, and the ultrasound emanating from the document of value is then emitted by means of the at least an ultrasonic transmitter / receiver is received and received signals are formed, the at least one ultrasonic transmitter and / or the at least one ultrasonic receiver or the at least one ne ultrasonic transmitter / receiver have at least one capacitive, micromechanical ultrasonic transducer. The method according to the invention can in particular be carried out by means of a device according to the invention, the ultrasonic transmitters being used as the ultrasonic transmitter or ultrasonic receiver or ultrasonic transmitter / receiver in the method or ultrasound receiver or ultrasound transmitter / receiver of the facility are used.

In the context of the present invention, capacitive, micromechanical ultrasonic transducers are understood to mean ultrasonic transducers which have two, preferably flat, electrodes that form a capacitor. A first of the electrodes is formed, for example as a conductive layer region, on a substrate or, if the substrate is conductive, can be formed by a region of the substrate; the other electrode is formed, for example as a conductive layer area, on a membrane or plate spaced apart from the first electrode or, if the membrane or plate is conductive, can be formed by this so that the electrodes form the capacitor. The membrane or plate is designed in such a way that when a suitable electrical voltage is applied between the electrodes, a force is exerted between the membrane or plate and the substrate, which results in a movement of at least part of the membrane or plate, for example a change in shape. If a suitable time-varying voltage is applied between the electrodes, through which the electrodes attract or repel each other, the resulting movement of at least a part of the membrane can excite sound waves. Such structures are preferably produced using methods for producing micromechanical structures.

As an alternative, the facility has an ultrasonic transmitter and receiver. The ultrasonic transmitters and / or the ultrasonic receivers each have at least one ultrasonic transducer, preferably a capacitive, micromechanical ultrasonic transducer. The ultrasonic transmitter sends in response to transmission signals or to the activation by transmission signals, ie in response to transmission signals fed to it, ultrasound in Direction of the transport path, the ultrasound receiver receives ultrasound that was or is generated by means of the ultrasound transmitter, possibly after interaction with a value document, ie reflection on or transmission through the value document, and generates corresponding received signals. As far as the respective ultrasonic transmitter or respective ultrasonic receiver has the at least one capacitive micromechanical ultrasonic transducer, the ultrasound is transmitted in response to activation by transmission signals by means of the at least one capacitive, micromechanical ultrasonic transducer of the respective ultrasonic transmitter or the ultrasound is received by means of the at least one capacitive, micromechanical ultrasonic transducer of the respective ultrasonic receiver.

According to another alternative, however, it is possible for the device to have ultrasonic transmitters / receivers, that is to say elements that serve both as ultrasonic transmitters and as ultrasonic receivers. These can each have at least one capacitive, micromechanical ultrasonic transducer. This can first emit an ultrasound pulse as an ultrasound transmitter in response to a corresponding transmission signal, in order then to be used as a receiver after the emission of the ultrasound pulse, which receives the ultrasound pulse reflected from the value document and forms and outputs at least one corresponding reception signal. This embodiment in particular is made possible by the fact that capacitive, micromechanical ultrasonic transducers can emit pulses of very short duration, preferably through appropriate activation with signals, in particular control signals, that is, they do not oscillate for a long time. This embodiment is characterized in particular by a compact structure and is therefore particularly suitable for use in smaller value document processing devices.

The ultrasound receivers or the ultrasound transmitters / receivers in their function as receivers receive ultrasound in a frequency range in which the ultrasound transmitters or ultrasound transmitters / receivers send ultrasound as transmitters and form received signals that have at least one property of the received ultrasound, for example the intensity or amplitude or frequency.

In the device, the ultrasonic transmitters and ultrasonic receivers can preferably be arranged and designed in such a way that one of the ultrasonic transmitters and at least one of the ultrasonic receivers each form an ultrasonic path. The ultrasound emitted by the respective ultrasound transmitter essentially propagates along this, i. H. except for scattering or diffraction losses, to the ultrasonic receiver. An ultrasonic transmitter and an ultrasonic receiver, which form an ultrasonic path, are referred to below as being assigned to one another. This alignment or assignment can, in particular, enable spatially resolved properties to be recorded, as will become clear below.

On the one hand, the ultrasonic transmitter and the ultrasonic receiver of an ultrasonic path can preferably be arranged on opposite sides of the transport path. Documents of value are then transported through between the ultrasonic transmitters and the ultrasonic receivers. The fact that an ultrasound transmitter and an ultrasound receiver form an ultrasound path is understood when the ultrasound transmitter and ultrasound receiver are arranged on opposite sides of the transport path that the ultrasound transmitter emits ultrasound essentially in the direction of the ultrasound receiver and the ultrasound receiver receives ultrasound from the ultrasound transmitter; ie under the ultrasonic path the path along which the ultrasound essentially propagates from the ultrasound transmitter to the ultrasound receiver is understood. In particular, this can be the straight connecting line between the ultrasonic transmitter and the ultrasonic receiver. Both the ultrasonic transmitter and the ultrasonic receiver, which form an ultrasonic path, preferably contain at least one capacitive micromechanical ultrasonic transducer.

In the device, it is also possible that the ultrasonic transmitters and ultrasonic receivers are arranged and designed in such a way that one of the ultrasonic transmitters and at least one of the ultrasonic receivers are arranged on the same side of the transport path, so that the ultrasound emitted by a respective one of the ultrasonic transmitters only after interaction with one of the documents of value in the transport path is received by one of the ultrasonic receivers and the ultrasonic transmitter and the ultrasonic receiver thus form an ultrasonic path. In this case, the ultrasound path is understood to mean the path along which the ultrasound transmitted by the ultrasound transmitter essentially propagates as far as the document of value and, after reflection thereon, to the ultrasound receiver. Preferably, both the ultrasonic transmitter and the ultrasonic receiver, which form an ultrasonic path, then also contain at least one capacitive micromechanical ultrasonic transducer.

If the device has an ultrasonic transmitter / receiver, the ultrasonic path preferably runs from the respective ultrasonic transmitter / receiver to the value document and back.

The device can preferably also have a control and evaluation device which is connected to the ultrasonic transmitters and ultrasonic receivers is connected via signal connections, and forms transmission signals for the output of ultrasound by at least one of the ultrasound transmitters and outputs them to this and receives and processes reception signals at least one of the ultrasound receivers. If the device contains ultrasonic transmitters / receivers, it can have a control and evaluation device which is connected to the ultrasonic transmitters / receivers via signal connections, and forms transmission signals for the output of ultrasound by at least one of the ultrasonic transmitters / receivers and sends them to and received signals receiving and processing the at least one of the ultrasonic transceivers; in particular, the same signal connection can be used for transmit signals and receive signals. This makes it easier to carry out an examination with spatial resolution. In the method, if the device according to the invention is used, the control and evaluation device can be used in particular for generating and outputting the transmission signals and for receiving and processing the received signals.

The control and evaluation device is used, among other things, to generate and output the transmission signals and to receive and process the received signals. For this purpose, it can preferably have at least one microcontroller and / or at least one processor and / or at least one FPGA; these are then preferably programmed accordingly. If the ultrasonic transmitters or ultrasonic receivers are formed on a circuit carrier, for example a printed circuit board, at least some elements of the control and evaluation device can also be arranged on this.

In principle, the transmission signals can be formed by the control and evaluation device in such a way that the ultrasonic transmitters respond to the transmission signals or continuously emit ultrasound in response to the transmitted signals. However, it is preferred in the device that the at least one capacitive micromechanical ultrasonic transducer of at least some of the ultrasonic transmitters or ultrasonic transmitters / receivers and the control and evaluation device are designed so that the at least one capacitive micromechanical ultrasonic transducer of the respective ultrasonic transmitter or the ultrasonic transmitter / -Receiver emits ultrasound pulses of predetermined frequency and duration, which are preferably shorter than 100 milliseconds, as a function of transmission signals from the control and evaluation device or in response to transmission signals from the control and evaluation device. In the method it is preferred that the at least one capacitive micromechanical ultrasonic transducer of at least some of the ultrasonic transmitters or ultrasonic transmitters / receivers is designed and transmission signals are formed and emitted in such a way that the at least one capacitive micromechanical ultrasonic transducer of the respective ultrasonic transmitter or the ultrasonic transmitter / -receiver emits ultrasound pulses of predetermined frequency and duration as a function of the transmission signals or in response to the transmission signals, which are preferably shorter than 100 milliseconds. In the case of the method, the transmission signals can be generated and emitted by a control and evaluation device. In the device and the method, all capacitive micromechanical ultrasonic transducers and the control and evaluation device can particularly preferably be designed to emit pulses of ultrasound of a predetermined frequency and duration, which are preferably shorter than 100 milliseconds. The frequency is preferably in the range from 20 kHz to 1 GHz, particularly preferably in the range between 40 kHz and 1 MHz. The pulse duration is preferably understood to mean the width at half the maximum of the sound intensity as a function of time (FWHM), with averaging over a period corresponding to the frequency.

The use of ultrasound pulses, ie pulses of ultrasound, which preferably has the specified frequency, has the advantage that a spatial resolution of the examination is made possible if the value document is examined with the ultrasound during transport past the device or through it. A comparatively high spatial resolution in the transport direction is made possible by the fact that capacitive, micromechanical ultrasonic transducers are not very sluggish if they are appropriately designed and have a corresponding transmission signal. H. respond quickly to changes in the transmit signals. Therefore, short pulses can be generated relatively easily. The advantage then results that a high spatial resolution can be achieved. Furthermore, minor problems should arise due to undesired ultrasonic pulses reflected on the value document.

In order to be able to receive such ultrasonic pulses also individually, it is preferred in the device that the at least one capacitive micromechanical ultrasonic transducer of at least some of the ultrasonic receivers or ultrasonic transmitters / receivers is each designed so that it receives ultrasonic pulses of a predetermined frequency and duration, which are preferably shorter are than 100 milliseconds, and forms corresponding received signals, and that the control and evaluation device is designed to receive and process the received signals. In the method, it is preferred that the at least one capacitive micromechanical ultrasound transducer of at least some of the ultrasound receivers or ultrasound transmitters / receivers is each designed such that it receives ultrasound pulses of a predetermined frequency and duration, which are preferably shorter than 100 milliseconds, and forms corresponding received signals , and, preferably by means of the control and evaluation device of the device according to the invention, receive and process the received signals become. These ultrasonic transmitters and ultrasonic receivers each preferably form an ultrasonic path. The control and evaluation device can in particular be designed in such a way that it filters the received signals with regard to the frequency, so that the capacitive micromechanical ultrasonic transducers do not need to be used for ultrasound with a frequency close to a possible mechanical resonance frequency. The frequency is given by the frequency of the transmission signals for the assigned ultrasonic transmitter or the ultrasound emitted by the assigned ultrasonic transmitter. The filtering can also consist of attenuating or suppressing signal components with frequencies outside a predetermined narrow band within which the frequency of the transmitted ultrasound lies.

In principle, the capacitive, micromechanical ultrasonic transducers can be designed individually and held in or on the device. However, it is preferred in the device that at least one of the ultrasonic transmitters has at least two capacitive, micromechanical ultrasonic transducers and / or at least two of the ultrasonic transmitters each have at least one capacitive, micromechanical ultrasonic transducer, and that these capacitive, micromechanical ultrasonic transducers are arranged on a chip and each has electrodes which are contacted with conductor tracks on the respective chip and / or that at least one of the ultrasonic receivers has at least two capacitive, micromechanical ultrasonic transducers and / or at least two of the ultrasonic receivers each have at least one capacitive, micromechanical ultrasonic transducer, and these capacitive, micromechanical ultrasonic transducers on one Chip are arranged, each having electrodes that are contacted with conductor tracks on the respective chip or at least one of the ultrasonic transmitters / receivers ens two capacitive, micromechanical ultrasonic transducers and / or at least two of the ultrasonic transmitters / receivers each have at least one capacitive, micromechanical ultrasonic transducer, and these capacitive, micromechanical ultrasonic transducers are arranged on a chip, and preferably each have electrodes that are contacted with conductor tracks on the respective chip . This embodiment has the advantage that the capacitive, micromechanical ultrasonic transducers can not only be produced and contacted in large numbers, fairly precisely aligned with one another, in the same or different sizes, but can also be easily assembled to form an ultrasonic sensor, since the transducers are aligned with one another is given by the chip. At least 4, particularly preferably at least 20, capacitive, micromechanical ultrasonic transducers are preferably formed on a single chip.

This embodiment offers the advantage that the ultrasonic transducers can be easily manufactured with small distances from one another. In the device, adjacent capacitive, micromechanical ultrasonic transducers formed on a chip preferably have a distance between 100 μm and 10 mm in the direction of transport and / or a distance between 100 μm and 10 mm transverse to the direction of transport, provided that the capacitive, micromechanical ultrasonic transducers in the respective Identify the direction of neighboring capacitive, micromechanical ultrasonic transducers. This makes it possible to measure ultrasonic properties along tracks on the document of value parallel to the transport direction, which are very closely adjacent, and thus to obtain these ultrasonic properties with a high spatial resolution transversely to the transport direction of the document of value. In particular, gaps running in the transport direction, as they are generally further spaced from one another in the case of piezoelectric ones, can be used Ultrasonic transducers are created that can be kept small or avoided entirely when recording ultrasonic properties.

The arrangement or formation on a chip also offers the advantage that the ultrasonic transducers can be easily manufactured with predetermined shapes and a wide range of dimensions. In particular, it can be preferred in the device that at least one of the capacitive, micromechanical ultrasonic transducers has an extension between 100 μm and 10 mm in the transport direction and / or an extension between 100 μm and 10 mm transverse to the transport direction. This preferably applies to all capacitive, micromechanical ultrasonic transducers. Such a range of dimensions makes it possible to obtain a good spatial resolution of the ultrasonic properties. The extension is understood to mean the length of the longest straight stretch that runs in the specified direction and is limited by edge sections of the respective ultrasonic sensor.

The device can also have at least two chips with capacitive, micromechanical ultrasonic transducers, wherein the capacitive, micromechanical ultrasonic transducers of an ultrasonic transmitter or ultrasonic receiver or ultrasonic transmitter / receiver are preferably arranged or formed on only one of the chips.

A difficulty in the spatially resolved detection of ultrasonic properties is often that ultrasound transmitted on an ultrasonic path can also be detected directly or indirectly by ultrasonic receivers in adjacent ultrasonic paths. This leads to undesirable inaccuracies in the measurement on neighboring ultrasonic paths. In the device, it is therefore preferred that the control and evaluation device is designed to emit transmission signals, preferably simultaneously, to at least two different, preferably adjacent, ultrasonic transmitters or ultrasonic transmitters / receivers, so that these emit ultrasound at different frequencies or pulses of ultrasound at different frequencies, and receive signals from the respective ultrasonic transmitter to receive and process an ultrasound receiver or ultrasound transmitter / receiver forming an ultrasound path, preferably according to the frequency of the ultrasound emitted by the respective ultrasound transmitter, ie depending on the position of the ultrasound receiver or the relative position of the ultrasonic receivers to each other or the relative position of the ultrasonic transmitters to each other to filter. In the method, it is preferred that transmission signals are emitted to at least two different, preferably adjacent ones of the ultrasonic transmitters or ultrasonic transmitters / receivers, so that they emit ultrasound at different frequencies or pulses of ultrasound at different frequencies, and receive signals from the respective ultrasonic transmitter an ultrasound path forming ultrasound receiver or the ultrasound transmitter / receiver or when receiving ultrasound generated by the ultrasound transmitter are received and processed, preferably accordingly, ie filtered depending on the position of the ultrasound receiver or the relative position of the ultrasonic receivers to each other or the relative position of the ultrasonic transmitters to each other become. In particular, the frequency of the ultrasound can be a function of the position of the ultrasound path along which the ultrasound propagates. Furthermore, the ultrasonic transmitters can particularly preferably be directly adjacent. The capacitive micromechanical ultrasonic transducers can preferably be designed such that they are each designed to emit ultrasonic pulses of the ultrasonic frequency corresponding to their position. The filtering of the received signals from one of the ultrasonic receivers can preferably take place at the frequency at which the assigned ultrasound transmitter emitted ultrasound. This embodiment has the advantage that ultrasound that has been sent on an ultrasound path cannot be received or only weakly received by the receiver of an adjacent ultrasound path and / or the corresponding interfering signals can be filtered out. In this way, the spatial resolution can be increased, since the distance between neighboring ultrasonic transmitters or ultrasonic receivers, which is otherwise necessary due to the risk of interference from measurements along neighboring ultrasonic paths or crosstalk, can be selected to be smaller. Depending on the design of the capacitive, micromechanical ultrasonic transducers in relation to their transmission and reception spectrum and, above all, the control and evaluation device, the overall result can be a very narrow-band characteristic for an ultrasonic path and thus particularly good suppression or avoidance of interference .

According to a further possibility, optionally combinable with the possibility described in the previous paragraph, to reduce disturbances in the measurement at locations adjacent in the direction of the transport direction of the document of value, at least one sequence of ultrasonic pulses can be generated in which successive ultrasonic pulses have a different predetermined ultrasonic frequency exhibit. In the device, the control and evaluation device can preferably be designed to output transmission signals to at least one of the ultrasonic transmitters or receivers, ie to control at least one of the ultrasonic transmitters and / or the ultrasonic transmitters / receivers with transmission signals that this emits a sequence of ultrasonic pulses, of which at least two successive ones have a predetermined different frequency and received signals from the dem to receive and process the respective ultrasound transmitter associated ultrasound receiver or the ultrasound transmitter / receiver, preferably to filter according to the frequencies or the sequence of frequencies of the emitted pulses. In the method, it is preferred that transmission signals are output to at least one of the ultrasound transmitters, i.e. at least one of the ultrasound transmitters is controlled with transmission signals in such a way that it emits a sequence of ultrasound pulses, of which at least two successive ones have a predetermined different frequency and receive signals from the respective ultrasound transmitter associated ultrasound receiver or the ultrasound transmitter / receiver received and processed, preferably filtered according to the frequency sequence of the emitted pulses. The ultrasonic pulses of the sequence thus each have an ultrasonic frequency according to a predetermined frequency sequence. This further development has the advantage that echoes, that is to say pulses reflected from the document of value and not intended for reception, at most a weak one, preferably not have any influence on the measurement at locations adjacent in the transport direction. In particular, if capacitive micromechanical ultrasonic transducers are not operated at their resonance frequency, short pulses and thus a high spatial resolution can simply be generated.

In principle, the ultrasonic transmitters and / or ultrasonic receivers or ultrasonic transmitters / receivers each need to have only one capacitive micromechanical ultrasonic transducer. However, it is also possible that in the device according to the invention or the method according to the invention, preferably at least one of the ultrasonic transmitters and / or ultrasonic receivers or ultrasonic transmitters / receivers has at least two capacitive micromechanical ultrasonic transducers. These can be designed to be identical, at least in terms of their properties. In the process transmit signals are preferably transmitted to these capacitive, micromechanical ultrasonic transducers in such a way that they transmit ultrasound at the same frequency, or the received signals are evaluated for a given, identical frequency. In the device or the method, the capacitive, micromechanical ultrasonic transducers of the at least one ultrasonic transmitter or ultrasonic receiver or ultrasonic transmitter / receiver can be connected to the control and evaluation device, for example, and the control and evaluation device can be designed such that it is connected to the ultrasonic transducer Emits transmission signals, so that they emit ultrasound with the same frequency, or that it processes or evaluates the received signals for the same frequency, for example filters and processes them.

For example, the ultrasonic transducers can be connected in parallel; the corresponding electrodes of the ultrasonic transducers are then connected to the same connections of the control and evaluation device. The transmission signals do not necessarily differ, except perhaps in terms of their size, from those for ultrasonic transmitters or ultrasonic transmitters / receivers with only one capacitive, micromechanical ultrasonic transducer. This can be particularly advantageous when capacitive micromechanical ultrasonic transducers are to emit ultrasound with a frequency or intensity or in a solid angle or receive with a frequency or intensity or from a solid angle for which the shape and vibration properties of the ultrasonic transducers are not very favorable.

In the device, however, the at least two ultrasonic transducers can also be individually connected to the control and evaluation device and the latter can be designed in such a way that the control and evaluation device can be connected to this ultrasonic transducer can emit transmission signals individually. The control and evaluation device is then preferably designed in such a way that it individually emits transmission signals to these capacitive, micromechanical ultrasonic transducers such that they emit ultrasound with the same predetermined frequency, ie that they emit ultrasound with the same frequency in response to the transmission signals, or that they Received signals from the at least two capacitive micromechanical ultrasonic transducers, which receive ultrasound of the same frequency, are processed or evaluated together for the same frequency. In particular, the transmission signals can then be formed such that the at least two ultrasound transducers emit the ultrasound essentially in phase or with the same phase. This embodiment can be advantageous, for example, in order to generate an ultrasonic field with a higher intensity or a greater extent.

In a preferred variant, the control and evaluation device can be designed in such a way that it emits such transmission signals to the capacitive micromechanical ultrasonic transducers, which at least partially form an ultrasonic transmitter, that they emit ultrasound with the same frequency and different phase, preferably so that the emitted ultrasound of the two transducers is bundled or its direction is changed. In the method, in this variant, the ultrasonic transducers are preferably given such transmit signals that they emit ultrasound with the same frequency and different phase, preferably so that the emitted ultrasound of the two transducers is bundled or its direction is changed. This allows the directional characteristic of the emitted ultrasound and thus the local resolution of the device to be improved without the intensity of the ultrasound having to be reduced. In a further variant, the control and evaluation device can also be designed to make the phases time-dependent to change that the main transmission direction of the resulting ultrasound is panned in a predetermined manner.

The device according to the invention and the method according to the invention can in particular be used in devices for processing documents of value. The present invention therefore also relates to a device for processing documents of value with a feed device for receiving documents of value to be processed, an output device for outputting or receiving the processed documents of value, a transport device for transporting the documents of value from the feed device along a transport path to the output device and at least one The device according to the invention arranged in the area of a section of the transport path for examining the documents of value and / or the transport of the documents of value which are transported along the transport path.

In the case of the device and the method, it can suffice for processing the received signals to determine only ultrasonic transmission or reflectance values as a function of a location, preferably for at least one predetermined frequency, on a value document.

In the device, however, the control and evaluation device can also be designed to determine from the received signals at least one value that represents the weight per unit area and / or the thickness of the document of value. In the method, at least one value can preferably be determined from the received signals, preferably by means of an evaluation device or the control and evaluation device, which represents the weight per unit area and / or the thickness of the document of value. The control and evaluation device can particularly preferably be added to the device be designed to determine values from the received signals which represent the weight per unit area or the thickness as a function of the location on the value document. In the method, values can be determined from the received signals, preferably by means of an evaluation device or the control and evaluation device, which represent the weight per unit area or the thickness as a function of the location. In this way, for example, the presence of watermarks and possibly their properties and / or the presence of an adhesive strip on a document of value can be examined. This makes it possible to determine properties of the value document which play a role in its authenticity or condition.

In the method, the processing of the received signals can include the further step of determining whether a value document for the received signals was received, transported as a single value document, or at least partially overlapping with another value document, and if at least partially overlapping value documents are identified, a Output signal representing the result of the determination. In the device, the feed device can preferably have a separator, by means of which documents of value can be separated from a stack of documents of value in an input area and fed to the transport device. In the device, for example, the control and evaluation device can then be further designed to determine when processing the received signals whether a value document for the received signals was received, transported as a single value document, or at least partially overlapping with another value document, and upon determination at least partially overlapping documents of value to emit a signal representing a result of the determination. In particular, the transport of a value document can be close, preferably immediately after the singler to examine whether a single value document is being transported. The ultrasonic transducers of the device according to the invention are then preferably arranged in the area of the transport path close to or on the separator. The device according to the invention is particularly suitable for this because it takes up little space. The event that documents of value overlap at least partially after singulation and are thus fed to the transport device is often referred to as a double print or multiple print.

Furthermore, the transport of the value documents can be examined to determine whether or when a predetermined edge, for example the front edge of a value document in the transport direction, passes a predetermined location and / or whether or how the value document is aligned with a predetermined of its edges relative to the transport direction.

Thus, in an advantageous variant of the device, the control and evaluation device can preferably be designed to recognize when processing the received signals using the received signals whether and / or when at least one predetermined edge, preferably the one in front in the transport direction and / or the one in Transport direction rear edge, a document of value passes a predetermined location on the transport path, and / or to recognize their position and then preferably to output a corresponding signal, in particular the signal representing the time or the event. In the method, when processing the received signals, these are then preferably used to recognize whether and / or when at least one predetermined edge, preferably the front edge in the transport direction and / or the rear edge in the transport direction, of a document of value passes a predetermined location, and / or to recognize their location. After recognizing edges you can For example, the arrival of a document of value at the facility, or a departure of the document of value from a detection area of the facility can be detected, thereby enabling transport monitoring.

But it is also possible for the value document to run at an angle, d. H. an alignment of the edges of the value document neither parallel nor perpendicular to the transport direction, to recognize or the dimensions of a value document.

In the device, the ultrasound transmitters or ultrasound transmitters / receivers can be arranged on a predetermined section of the transport path for this purpose. Furthermore, the device can have a machine control device which receives the signal from the device and controls components of the device as a function of the signal.

Fig.1

eine schematische Ansicht einer Wertdokumentbearbeitungsvorrichtung, im Beispiel einer Banknotensortiervorrichtung,

Fig. 2

eine schematische Darstellung eines Beispiels für eine Einrichtung zur Untersuchung von Wertdokumenten und/oder des Transports von Wertdokumenten mittels Ultraschall in der Vorrichtung in Fig. 1,

Fig. 3

eine schematische Darstellung eines Schaltungsträgers der Einrichtung in Fig. 2 mit auf einem Chip gebildeten kapazitiven mikromechanischen Ultraschallwandlern in einer Draufsicht,

Fig.4

eine schematische Schnittansicht durch einen Abschnitt des Chips in Fig. 3,

Fig. 5

eine schematische Seitenansicht des Schaltungsträgers in Fig. 3 mit einer Kontaktierung zwischen dem Chip und dem Schaltungsträger,

Fig.6

eine schematische Darstellung eines Abschnitts eines zweiten Beispiels für eine Wertdokumentbearbeitungsvorrichtung mit einer Zuführeinrichtung und einem zweiten Beispiel für eine Einrichtung zur Untersuchung von Wertdokumenten und/oder des Transports von Wertdokumenten,

Fig.7

eine schematische Darstellung der Einrichtung zur Untersuchung von Wertdokumenten und/oder des Transports von Wertdokumenten der Vorrichtung in Fig. 6,

Fig. 8

eine Fig. 2 entsprechende schematische Darstellung eines dritten Beispiels für eine Einrichtung zur Untersuchung von Wertdokumenten und/oder des Transports von Wertdokumenten mittels Ultraschall,

Fig. 9

eine schematische Darstellung der von der Einrichtung in Fig. 8 verwendeten Ultraschallfrequenzen für die Ultraschallsender und Ultraschallempfänger,

Fig. 10

eine Fig. 2 entsprechende schematische Darstellung eines vierten Beispiels für eine Einrichtung zur Untersuchung von Wertdokumenten und/oder des Transports von Wertdokumenten mittels Ultraschall,

Fig. 11

eine schematische Darstellung der von der Einrichtung in Fig. 10 verwendeten Ultraschallfrequenzen für die Ultraschallsender und Ultraschallempfänger,

Fig. 12

eine schematische Darstellung der von einer Einrichtung eines fünften Beispiels verwendeten Ultraschallfrequenzen für die Ultraschallsender und Ultraschallempfänger,

Fig. 13

eine schematische Darstellung eines Abschnitts eines sechsten Beispiels für eine Wertdokumentbearbeitungsvorrichtung mit einer Zuführeinrichtung und einem sechsten Beispiel für eine Einrichtung zur Untersuchung von Wertdokumenten und/oder des Transports von Wertdokumenten,

Fig. 14

eine grob schematische Ansicht auf eine Einrichtung zur Untersuchung von Wertdokumenten und/oder des Transports von Wertdokumenten eines siebten Ausführungsbeispiels in einer Richtung auf den Transportpfad,

Fig. 15

eine grob schematische Ansicht auf die Einrichtung in Fig. 14 in einer Richtung quer zu dem Transportpfad,

Fig. 16

eine grob schematische Ansicht auf einen Abschnitt eines Chips von oben mit einem Ultraschallsender, der vier parallel geschaltete kapazitive mikromechanische Ultraschallwandler aufweist.

Fig. 17

eine grob schematische Ansicht auf einen Abschnitt eines Chips von oben mit einem Ultraschallsender, der drei kapazitive mikromechanische Ultraschallwandler aufweist,

Fig. 18

unterschiedliche Richtcharakteristiken des Schallfeldes bei unterschiedlicher Phasenansteuerung mehrerer kapazitiver, mikromechanischer Ultraschallwandler eines Ultraschallsenders,

Fig. 19

eine schematische Darstellung eines Schaltungsträgers eines weiteren Beispiels für eine Einrichtung zur Untersuchung von Wertdokumenten und/oder des Transports von Wertdokumenten mit auf zwei Chips gebildeten kapazitiven mikromechanischen Ultraschallwandlern in einer Draufsicht,

Fig. 20

eine schematische Darstellung eines Chips mit darauf entlang einer Zeile quer zur Transportrichtung gebildeten in gleichem Abstand mit gleicher Größe ausgebildeten kapazitiven mikromechanischen Ultraschallwandlern in einer Draufsicht,

Fig.

21 eine schematische Darstellung eines Chips mit darauf entlang einer Zeile quer zur Transportrichtung ausgebildeten in variablem Abstand mit unterschiedlicher Größe ausgebildeten kapazitiven mikromechanischen Ultraschallwandlern in einer Draufsicht

Fig. 22

eine schematische Darstellung eines Chips mit darauf entlang einer Zeile quer zur Transportrichtung ausgebildeten Ultraschallsendern mit unterschiedlichen Anzahlen von kapazitiven mikromechanischen Ultraschallwandlern in einer Draufsicht, und

Fig. 23

eine schematische Darstellung eines Chips mit darauf auf einem Quadratgitter ausgebildeten in gleichem Abstand mit gleicher Größe ausgebildeten kapazitiven mikromechanischen Ultraschallwandlern in einer Draufsicht

In the following, the invention is explained further by way of example with reference to the drawings. Show it:

Fig.1

a schematic view of a value document processing device, in the example of a bank note sorting device,

Fig. 2

a schematic representation of an example of a device for examining documents of value and / or the transport of documents of value by means of ultrasound in the device in FIG Fig. 1 ,

Fig. 3

a schematic representation of a circuit carrier of the device in Fig. 2 with capacitive micromechanical ultrasonic transducers formed on a chip in a top view,

Fig. 4

a schematic sectional view through a portion of the chip in FIG Fig. 3 ,

Fig. 5

a schematic side view of the circuit carrier in FIG Fig. 3 with a contact between the chip and the circuit carrier,

Fig. 6

a schematic representation of a section of a second example for a value document processing device with a feed device and a second example for a device for examining value documents and / or the transport of value documents,

Fig. 7

a schematic representation of the device for examining documents of value and / or the transport of documents of value of the device in FIG Fig. 6 ,

Fig. 8

a Fig. 2 corresponding schematic representation of a third example of a device for examining documents of value and / or the transport of documents of value by means of ultrasound,

Fig. 9

a schematic representation of the device in Fig. 8 used ultrasonic frequencies for the ultrasonic transmitters and ultrasonic receivers,

Fig. 10

a Fig. 2 corresponding schematic representation of a fourth example of a device for examining documents of value and / or the transport of documents of value by means of ultrasound,

Fig. 11

a schematic representation of the device in Fig. 10 used ultrasonic frequencies for the ultrasonic transmitters and ultrasonic receivers,

Fig. 12

a schematic representation of the ultrasonic frequencies used by a device of a fifth example for the ultrasonic transmitters and ultrasonic receivers,

Fig. 13

a schematic illustration of a section of a sixth example of a value document processing device with a feed device and a sixth example of a device for examining value documents and / or the transport of value documents,

Fig. 14

a roughly schematic view of a device for examining documents of value and / or the transport of documents of value of a seventh embodiment in one direction of the transport path,

Fig. 15

a roughly schematic view of the device in Fig. 14 in a direction across the transport path,

Fig. 16

a roughly schematic view of a section of a chip from above with an ultrasonic transmitter which has four capacitive micromechanical ultrasonic transducers connected in parallel.

Fig. 17

a roughly schematic view of a section of a chip from above with an ultrasonic transmitter that has three capacitive micromechanical ultrasonic transducers,

Fig. 18

different directional characteristics of the sound field with different phase control of several capacitive, micromechanical ultrasonic transducers of an ultrasonic transmitter,

Fig. 19

a schematic representation of a circuit carrier of a further example of a device for examining documents of value and / or the transport of documents of value with capacitive micromechanical ultrasonic transducers formed on two chips in a top view,

Fig. 20

a schematic representation of a chip with capacitive micromechanical ultrasonic transducers formed on it along a line transversely to the transport direction, equally spaced and of the same size, in a top view,

Fig.

21 shows a schematic representation of a chip with capacitive micromechanical ultrasonic transducers formed thereon along a line transversely to the transport direction and at variable spacing with different sizes in a plan view

Fig. 22

a schematic representation of a chip with ultrasonic transmitters formed thereon along a line transversely to the transport direction with different numbers of capacitive micromechanical ultrasonic transducers in a plan view, and

Fig. 23

a schematic representation of a chip with formed thereon on a square grid at the same distance with the same size trained capacitive micromechanical ultrasonic transducers in a plan view

A value document processing device 10 in Fig. 1 , in the example a device for processing documents of value 12 in the form of banknotes, is designed to sort documents of value depending on the state determined by means of the document processing device 10 and the authenticity of processed documents of value checked by means of the document processing device.

It has a feed device 14 for feeding documents of value, an output device 16 for receiving processed, i.e. H. sorted documents of value, and a transport device 18 for transporting separated documents of value from the feed device 14 to the output device 16.

In the example, the feed device 14 comprises an input compartment 20 for a stack of documents of value and a singulator 22 for singling out documents of value from the stack of value documents in the input compartment 20 and provision for or feed to the transport device 18.

In the example, the output device 16 comprises three output sections 24, 25 and 26, into which processed documents of value can be sorted depending on the result of the processing, in the example verification. In the example, each of the sections comprises a stacking compartment and a stacking wheel, not shown, by means of which supplied documents of value can be stored in the stacking compartment.

The transport device 18 has at least two, in the example three branches 28, 29 and 30, at the ends of which one of the output sections 24 or 25 or 26 is arranged, and at the branches via switches 32 and 34 which can be controlled by actuating signals Documents of value can be fed to branches 28 to 30 and thus to output sections 24 to 26 as a function of control signals.

A sensor device 38 is arranged on a transport path 36 defined by the transport device 18 between the feed device 14, in the example more precisely the singler 22, and the first switch 32 in the transport direction T after the singler 22, which measures physical properties of the value documents while the value documents are being transported past and forms sensor signals which reproduce the measurement results and which represent sensor data. In this example, the sensor device 38 has three sensors, namely an optical remission sensor 40 that captures a remission color image of the value document, an optical transmission sensor 42 that captures a transmission image of the value document, and a device 44 for examining value documents and / or the transport of Documents of value that detects or measures spatially resolved ultrasonic transmission properties of the document of value. While the sensor device 38 outputs the sensor signals from the sensors 40 and 42 without evaluation, the sensor signals from the device 44 have already been at least partially evaluated.

A machine control and evaluation device 46 is connected to the sensor device 38 and the transport device 18, in particular the switches 32 and 34, via signal connections. In connection with the sensor device 38, it classifies a value document as a function of the signals from the sensor device 38 for the value document into one of specified sorting classes. These sorting classes can be specified, for example, as a function of a status value determined by means of the sensor data and an authenticity value that is likewise determined by means of the sensor data. For example, the values “fit for circulation” or “not fit for use” can be used as status values, and the values “forged”, “suspected of being falsified” or “genuine” as authenticity values. Depending on the ascertained sorting class, it controls the transport device 18, in this case more precisely the switches 32 or 34, by emitting actuating signals so that the value document is output in an output section of the output device 16 assigned to the class according to its sorting class determined during the classification. The assignment to one of the predefined sorting classes or the classification takes place as a function of criteria predefined for assessing the condition and assessing authenticity, which criteria depend on at least some of the sensor data.

In addition to corresponding interfaces for the sensor device 38 or its sensors and the device 44, the machine control and evaluation device 46 has a processor 48 and a memory 50 connected to the processor 48 in which at least one computer program with program code is stored Execution of the processor 48 controls the device or evaluates the sensor signals of the sensor device 38, in particular to determine a sorting class of a processed document of value, and controls the transport device 18 according to the evaluation.

The machine control and evaluation device 46 determines from the sensor signals of the sensor device 38 during a sensor signal evaluation at least one value document property that is necessary for checking the bank notes is relevant in terms of their authenticity and / or condition. Several of these properties are preferably determined. In this example, a transmission image and a remission image are determined as the optical value document properties and the ultrasound transmission as the acoustic property as a function of the location on the value document.

Depending on the value document properties, the machine control and evaluation device 46 determines sorting signals for the various sensors, which represent whether the value document properties determined represent an indication of the state or the authenticity of the value document or not. As a result of these signals, corresponding data can be stored in the machine control and evaluation device 46, for example the memory 50, for later use. Depending on the sorting signals, the machine control and evaluation device 46 then determines an overall result for the test according to a predetermined overall criterion and forms the sorting or control signal for the transport device 18 as a function of the result.

To process documents of value 12, documents of value 12 inserted into input compartment 20 as a stack or individually are fed singly and singly to transport device 18 by singler 22, which transports the singled documents of value 12 past sensor device 38. This records the properties of the value documents 12, with sensor signals being formed which reflect the properties of the respective value document. The machine control and evaluation device 46 detects the sensor signals, determines a sorting class as a function of them, in the example a combination of an authenticity class and a condition class of the respective value document and, depending on the result, controls the switches so that the value documents accordingly the ascertained sorting class is transported into an output section assigned to the respective sorting class.

To determine a sorting class on the basis of ultrasonic properties, the device 44 is used for examining a value document, which is used as a transmission ultrasonic sensor and which records ultrasonic transmission data as a function of a location on the value document and is structured as follows in the example (cf. Figs. 2 and 3 ).

The device 44 for examining documents of value by means of ultrasound has, as roughly schematically shown in FIG Fig. 2 shown, via a transmitter module 51 with a set of ultrasonic transmitters 52 and a receiver module 53 with a set of ultrasonic receivers 54, which are arranged on opposite sides of the transport path 36 along a line extending transversely to the transport direction. The ultrasound transmitters 52 emit ultrasound in response to corresponding transmission signals, and the ultrasound receivers 54, when receiving ultrasound, form at least one property of the ultrasound reproducing or describing reception signals. The number and arrangement of the ultrasonic transmitters 52 corresponds to the number and arrangement of the ultrasonic receivers 54. For the sake of better clarity, only a few ultrasonic transmitters or ultrasonic receivers are shown in the figures. In fact, there are in each case so many ultrasonic transmitters or receivers that the ultrasonic transmitters or receivers are arranged transversely to the transport path in a width that is greater than the corresponding extension of value documents of value document types intended for processing. In each case one of the ultrasound transmitters 52 and one of the ultrasound receivers 54 are aligned with one another in such a way that the ultrasound emitted by the respective ultrasound transmitter, in particular after being transmitted through one along the transport path 36, is transported Document of value 12, is aligned with the respective ultrasound receiver, so that the ultrasound is emitted essentially, ie except for scattering and diffraction effects, in the direction of the ultrasound receiver and the latter can receive the ultrasound. The respective ultrasonic transmitter and the respective ultrasonic receiver thus form an ultrasonic path 56, shown dotted, which in this exemplary embodiment is oriented essentially perpendicular to the transport path and whose end points are formed by the ultrasonic transmitter and the ultrasonic receiver; the ultrasonic transmitter and the ultrasonic receiver are referred to as being associated with one another.

To control the ultrasonic transmitters 52 with transmit signals and to receive received signals from the ultrasonic receivers 54 and to process them, these are individually connected to a control and evaluation device 47 of the device 44 by means of signal connections 49, which are only shown roughly schematically.

With each pair of one of the ultrasound transmitters and the ultrasound receiver 54 assigned to them or with each ultrasound path 56 in connection with the control and evaluation device 47, a value for the ultrasound transmission of the document of value 12 at the location exposed to the ultrasound can be determined at a given time .

The ultrasonic transmitters 52 and the ultrasonic receivers 54 are in FIGS Figures 3 and 4th shown roughly schematically. Each of the ultrasonic transmitters 52 and each of the ultrasonic receivers 54 has a capacitive micromechanical ultrasonic transducer. The capacitive micromechanical ultrasonic transducers of a pair of an ultrasonic transmitter 52 and an ultrasonic receiver 54, which forms an ultrasonic path 56, are identical educated. In this exemplary embodiment, all of the capacitive micromechanical ultrasonic transducers are designed essentially the same. The capacitive micromechanical ultrasonic transducers 63 of the ultrasonic transmitters 52 are formed on a chip 58; the same applies to the ultrasonic transducers of the ultrasonic receivers 54. In addition to the chip 58, the transmitter module has a circuit carrier 60, for example a printed circuit board, which also serves as a holder for the chip 58, on which the chip 58 is held and contacted with conductor tracks 59 on it. The conductor tracks 59 lead to the control and evaluation device 47.

Since the chips and, apart from the arrangement of the conductor tracks and electrical components, the circuit carriers are essentially constructed in the same way, it is sufficient to only describe the circuit carrier 60 with the chip 58 with the capacitive micromechanical ultrasonic transducers 63, which form the ultrasonic transmitters 52.

The chip 58 has a substrate 62 on which a first electrode 64 in the form of a section of an electrically conductive layer is formed in order to form an ultrasonic transducer 63 in each case. A further insulating layer 66 with cavities 68 is formed on this electrode 64. A region with a conductive layer, which forms a second electrode 70, is located above each of the cavities 68 on the insulating layer 66. The second electrodes 70 are therefore each arranged on a thin plate or membrane 72 which extends over the cavity 68. The electrodes 66 and 70 thus each form a capacitor. The electrodes together with the membrane 72 form the capacitive micromechanical ultrasonic transducer 63. The layer 66, in particular its material and thickness, are selected such that it can be elastically deformed by forces between the electrodes.

The electrodes 64 and 70_ are connected to conductor tracks, of which in Fig. 3 only the conductor tracks 59 are shown. The conductor tracks are connected to the control and evaluation device 47 and form signal connections 49 to it. When a voltage is applied between each pair of electrodes 64 and 70, which are separated by one of the cavities 68, a force is exerted on them, which leads to a deformation of the membrane 72. When applying a voltage with a suitable frequency in the range of the ultrasonic frequencies, ie with more than 20 kHz, a deformation of at least part of the membrane 72 can be generated with the corresponding frequency and ultrasound through the corresponding movement, the transducer works as a transmitter. Conversely, a deformation of the membrane 72 caused by the action of ultrasound leads to a corresponding change in the capacitance of the capacitor formed by the electrodes. The change in capacitance can be detected or a corresponding current can be generated by a suitable circuit of the ultrasonic transducer, not shown in the figures. This can be detected as a time-variable received signal by means of the control and evaluation device 47 connected via the signal connections 49.

In this example the electrodes 70 are connected via wires 74 (cf. Fig. 3 and 5 ) with the in Fig. 3 only partially shown conductor tracks 59 connected to the circuit carrier 60. The same applies to electrode 64, but the wires are not shown.

The membranes 72 over the cavities 68 and thus essentially the ultrasonic transducers 63 formed in this way have a circular shape in the example, which has an extension D, in the example a diameter, of 2 mm transversely to the emission or reception direction. The capacitive micromechanical Ultrasonic transducers have a distance A, more precisely a distance between the circumferential lines, of 1 mm across the transport direction. These dimensions are provided for capacitive micromechanical ultrasonic transducers that are to be operated for generating or receiving ultrasound at 500 kHz.

In order to generate and output the transmission signals and to receive and evaluate the received signals, the control and evaluation device 47 has, in addition to components on the circuit carriers, a processor or controller 75 which is connected to the signal connections 49. In addition to the processor 75, the control and evaluation device 47 has a memory in which instructions for a computer program are stored, during the execution of which the processor, as described below, generates and outputs the transmission signals or receives and processes or evaluates the received signals.

The control and evaluation device 47, in the example in particular the instructions of the computer program, and the capacitive micromechanical ultrasonic transducers are designed in such a way that the control and evaluation device 47 controls the ultrasonic transducers of the ultrasonic transmitters with transmission signals or outputs such transmission signals to them that the capacitive micromechanical ultrasonic transducer, preferably essentially simultaneously, emit ultrasonic pulses with an ultrasonic frequency of 500 kHz and a duration of 10 microseconds. The pulses are emitted with a repetition frequency of 5 kHz. These values are preferably suitable for transport speeds of approximately 5 m / s to 10 m / s.

Furthermore, the control and evaluation device 47 is designed to coordinate with the control of the ultrasonic transmitter 52 or the output of the transmission signals to receive reception signals of the ultrasonic receivers 54, which these form when the transmitted ultrasonic pulses or the ultrasonic pulses of the frequency of the transmitted ultrasonic pulses are received, which are formed by the transmitted ultrasonic pulses through interaction with a document of value. The control and evaluation device 47 is designed in particular to filter the received signals according to the frequency of the emitted ultrasound and the pulse duration and to determine a property of the received ultrasound pulses or an ultrasound property of the value document at the location of the ultrasound receiver. In the example, the ultrasonic property can be the ultrasonic transmission through the value document. The control and evaluation device 47 is also designed to form and emit sensor signals which describe the locations on the value documents and the ultrasonic transmission determined for each location.

When a value document 12 is transported along the transport path 36 between the ultrasound transmitters 52 and ultrasound receivers 54, the control and evaluation device 47 emits transmission signals to the ultrasound transmitters 52 so that they emit ultrasound pulses of the specified duration and frequency to the value document 12 at regular intervals and the ultrasound receivers 54 receive the ultrasound pulses emanating (transmitted) from the value document 12 with the formation of received signals. The control and evaluation device 47 detects the received signals in accordance with the transmitted signals, which reproduce the intensity or power of individual received ultrasonic pulses as a function of time and thus also the location on the value document because of the constant transport speed. It thus determines for the ultrasonic paths between the ultrasonic transmitters 52 and ultrasonic receivers 54 and thus locations that are caused by the ultrasound on the ultrasonic path are taken, ultrasonic transmission values which describe the ultrasonic transmission at the locations on the respective value document. The locations are on tracks on the value document along the direction of transport. This takes place line by line, so that after the document of value has passed through, ultrasound transmission values are available in a spatially resolved manner for the entire document of value. The transmission values are given simply by the received ultrasonic pulse energies, assuming a fundamentally constant transmission power of the ultrasonic transmitters 52. In other exemplary embodiments, however, it is also possible to divide the received ultrasonic pulse energies by a predetermined or measured ultrasonic pulse energy of transmitted pulses and thus to obtain standardized transmission values.

Sensor signals that describe the locations and the ultrasonic transmission values determined for them can then be transmitted from the control and evaluation device 47 to the machine control and evaluation device 46 and further evaluated by the latter. In other exemplary embodiments, the evaluation can also be carried out by the control and evaluation device. For example, the limpness of a document of value could be determined or a check for the presence of an adhesive strip carried out, as is known from the prior art.

A second embodiment in FIGS. 6 and 7 differs from the first exemplary embodiment in that a device 44 ′ for examining documents of value and / or for transporting documents of value by means of ultrasound is arranged on transport path 36 near singler 22. On the other hand, the device 44 in the sensor device 38 of the first exemplary embodiment is replaced by a conventional ultrasonic transmission sensor. Otherwise it will be appropriate for itself Components use the same reference numerals and the statements relating to the first exemplary embodiment also apply here accordingly. Fig. 6 therefore shows only a corresponding section from the device in FIG Fig. 1 including, inter alia, the feed device 14, a section of the transport path 36 and the device 44 '. The device 44 'differs from the device 44 on the one hand in that instead of the transmitter module 51 and the receiver module 53 or instead of the sets of ultrasonic transmitters 52 or ultrasonic receivers 54, only one transmitter / receiver module 51' with a set of ultrasonic transmitter / - receivers 52 'and accordingly the control and evaluation device 47 is replaced by a control and evaluation device 47'. As in Fig. 7 As illustrated, the ultrasonic transmitters / receivers 52 'are each individually connected via signal connections 49' to the control and evaluation device 47 '. For each of the ultrasonic transmitters / receivers 52 ', the transmitted signals and the received signals are therefore routed via the same signal connection.

The transmitter / receiver module 51 'is designed essentially like the transmitter module 51 of the first exemplary embodiment, so that the statements of the first exemplary embodiment also apply here accordingly. In particular, the ultrasonic transmitters / receivers 52 ′ each have a capacitive micromechanical ultrasonic transducer and are formed in a chip.

The chip is also held and contacted on a circuit carrier so that the ultrasound transmitters / receivers emit ultrasound onto the value document essentially in a vertical direction and receive ultrasound reflected back from the value document from a direction perpendicular to the transport plane of the value document. From each of the ultrasonic transmitters / receivers an ultrasound path 56 ′ is therefore formed, which in the example runs essentially perpendicular to a plane of the document of value. However, the conductor tracks and possibly other electrical components or circuits on the circuit carrier are modified in such a way that the capacitive micromechanical ultrasonic transducers can function as transmitters and receivers for ultrasound.

The control and evaluation device 47 'is designed in such a way that it emits transmission signals to the ultrasonic transmitter / receiver 52', in response to which the ultrasonic transmitter / receiver emits ultrasonic pulses as in the first exemplary embodiment, although the pulse duration is no longer than the transit time of one Ultrasonic pulse from the ultrasonic transmitter / receiver to the document of value, preferably not longer than between 10 microseconds and 10 ms.

As in FIGS. 6 and 7 recognizable, this device is characterized by the fact that it is particularly compact and takes up very little space.

The device or the sensor 44 'is designed to use ultrasound to detect whether a front or leading edge of a document of value in the transport direction passes the ultrasound transmitter / receiver arrangement or the transmitter / receiver module 51', i.e. at least one of the ultrasonic paths crosses.

For this purpose, the control and evaluation device 47 'is further designed to receive the received signals and to check whether their level is below a predetermined threshold value, which is characteristic of the fact that no ultrasound has been reflected from a value document or not, and to output a signal to the machine control and evaluation device 46 as a function of the result of the test. The control and evaluation device 47 'checks more precisely whether a pulse whose level is below the threshold value is followed by a pulse whose level is above the Threshold value lies. In this case, it emits a signal to the machine control and evaluation device 46, which indicates that a document of value is passing the device. This can use the signal to monitor the transport.

Alternatively or additionally, the device or the sensor 44, in particular its control and evaluation device, can be designed to use ultrasound to detect whether a rear edge of a document of value in the transport direction is passing the ultrasound transmitter / receiver arrangement, i.e. one of the ultrasonic paths crosses. If this event is recognized, a corresponding signal can be emitted by the control and evaluation device.

A third embodiment differs from the first embodiment in the control of the ultrasonic transmitters 52 and the evaluation of the received signals of the ultrasonic receivers 54, for which the device 44 is replaced by a device 44 ″. This differs from the device 44 only in that the control and evaluation device 47 is replaced by a control and evaluation device 47 ″ (cf. Fig. 8 ). The ultrasonic transducers are also adapted to the use of the different frequencies described below. In particular, in this exemplary embodiment, at least two different, preferably adjacent, ultrasound transmitters 52 for emitting ultrasound with different frequencies, in this example pulses of ultrasound with different frequencies, are controlled and received signals from The ultrasonic receiver 54 assigned to the respective ultrasonic transmitter 52 or which forms an ultrasonic path with it are received. The received signals are then processed, in particular filtered depending on the position of the ultrasonic receivers or the position of the ultrasonic receivers relative to the ultrasonic transmitters.

The ultrasonic transmitters are divided into two groups. The first group includes, viewed in the direction of the row of ultrasonic transmitters, the first and the next but one ultrasonic transmitter, the second the ultrasonic transmitters in between. The ultrasonic transmitters are therefore only assigned to one of the two groups.

The control and evaluation device 47 ″ is designed, on the one hand, to emit transmission signals to the ultrasonic transmitters of the first group so that they emit ultrasonic pulses with a predetermined pulse length and with a first predetermined ultrasonic frequency; it emits transmission signals to the ultrasonic transmitters of the second group, so that these emit ultrasonic pulses with the specified pulse length and with a second specified ultrasonic frequency.

According to the division of the ultrasonic transmitters into two groups, the ultrasonic receivers are also divided into two groups. The first group contains the ultrasonic receivers that are each assigned to one of the ultrasonic transmitters of the first group, the second group contains the ultrasonic receivers that are each assigned to one of the ultrasonic transmitters of the second group. The control and evaluation device 47 ″ is designed to process the received signals of the ultrasonic receivers of the first group according to the first ultrasonic frequency, in particular to filter them, and to process the received signals of the ultrasonic receivers of the second group accordingly the second ultrasonic frequency to process, in particular to filter.

More precisely, the control and evaluation device 47 ″ is designed like the control and evaluation device 47, but differs therefrom in two respects.

On the one hand, the control and evaluation device 47 ″ is designed to control the next neighboring ultrasound transmitter for the output of pulses of ultrasound with different frequencies by emitting corresponding transmission signals.

This is in Fig. 9 in which, symbolized by squares, the position of the ultrasonic sections 56 or the ultrasonic transmitters 52 and ultrasonic receivers 54 delimiting them are shown in planes parallel to the transport plane or a transported document of value. The ultrasonic sections or the ultrasonic transmitters 52 and ultrasonic receivers 54 delimiting them are arranged along a line transverse to the transport direction T. The squares are patterned according to the frequency of the ultrasound that the ultrasound transmitters 52 emit or the ultrasound receivers 54 associated with them receive. In the example, the lighter squares with the thinner puncture illustrate a first frequency of 400 kHz and the darker squares with the denser puncture represent a second frequency of 600 kHz.

The control and evaluation device 47 ″ is so designed that it emits transmission signals, upon receipt of which the ultrasound transmitters alternately emit ultrasound pulses of the first or second frequency along the line, so that between two ultrasound transmitters, the ultrasound of the first frequency emit, an ultrasonic transmitter is arranged that emits ultrasound of the second frequency ..

The ultrasound emitted in each case by one of the ultrasound transmitters is received by the assigned ultrasound receiver, here optionally after transmission through a document of value. This forms a received signal which is output to the control and evaluation device 47 ″.

The control and evaluation device 47 ″ is therefore designed, on the other hand, to receive and process received signals from the ultrasound receiver assigned to a respective ultrasound transmitter, in particular as a function of the properties of the ultrasound emitted by the assigned ultrasound transmitter, ie here also on the location of the ultrasound receiver or the relative position of the ultrasonic receivers to the ultrasonic transmitters.

On the one hand, the first and the second ultrasonic frequency are selected such that the ultrasonic properties of a document of value used do not depend heavily on which of the two frequencies they are detected at. On the other hand, they are selected so that the control and evaluation device 47 ″ in the received signals can filter out any components that may occur from adjacent ultrasonic paths by frequency-dependent filtering and thus suppress them for further processing.

This avoids crosstalk between directly adjacent ultrasonic transducers, although the ultrasonic pulses are essentially emitted simultaneously.

After filtering, the signals can be processed further as in the first exemplary embodiment.

A fourth exemplary embodiment differs from the first exemplary embodiment in that the ultrasonic transmitters are now controlled with transmit signals in such a way that they each emit a sequence of ultrasonic pulses, of which at least two successive ones have a different frequency. Received signals from the ultrasonic receiver assigned to the respective ultrasonic transmitter are received and processed, in particular filtered according to the frequency sequence of the emitted ultrasonic pulses. Compared to the first embodiment, only the device 44 is replaced by a device 44 ⁽⁴⁾ (cf. Fig. 10 ). This differs from the device 44 only in that the control and evaluation device 47 is replaced by a control and evaluation device 47 ⁽⁴⁾ and the capacitive micromechanical ultrasonic transducers are designed for the ultrasonic frequencies used. Otherwise, the statements relating to the first exemplary embodiment also apply here accordingly.

The first and second ultrasonic frequencies differ at least in such a way that the ultrasonic receivers used, in conjunction with the control and evaluation device that processes or evaluates their received signals, can clearly separate pulses with these frequencies, here by filtering in relation to the frequency. The closer the ultrasonic frequencies used are to one another, the longer pulse durations have to be used in order to still enable separation.

The control and evaluation device 47 ⁽⁴⁾ is designed on the one hand to generate transmission signals for each of the ultrasonic transmitters 52 and to send them to the respective To emit the ultrasonic transmitter, so that it emits a sequence of ultrasonic pulses in which directly successive different predetermined ultrasonic frequencies, here each have a different one of the two ultrasonic frequencies. The ultrasonic transmitters are activated by the control and evaluation device 47 ^{(4) in} such a way that they emit pulses essentially simultaneously, ie with a time delay of less than half a pulse duration between the ultrasonic transmitters. For example, this can be such that first transmission signals for a pulse with the first ultrasonic frequency are output to the ultrasonic transmitter, then corresponding transmission signals for the next pulse with the second ultrasonic frequency; this sequence is then repeated several times if necessary. The frequency of the ultrasonic pulses in the sequence therefore alternates with the sequence in the sequence.

On the other hand, the control and evaluation device 47 ⁽⁴⁾ is designed to receive the received signals of the ultrasonic transmitters in coordination with the transmitted signals and to process them, in particular to filter them, in accordance with the transmitted ultrasonic frequency.

This is in Fig. 11 illustrates, which schematically illustrates for three immediately successive pulses of a pulse train emitted at a time interval Δ at times t, t + Δ, t + 2Δ, which ultrasound frequency is used.

The representation corresponds to that in Fig. 9 . Squares symbolize the position of the ultrasonic paths 56 or the ultrasonic transmitters 52 and ultrasonic receivers 54 delimiting them in planes parallel to the transport plane or a transported document of value. The ultrasound paths or the ultrasound transmitters 52 and ultrasound receivers 54 delimiting them are arranged along a line across the direction of transport T. The squares are patterned according to the frequency of the ultrasound that the ultrasound transmitters 52 emit or the ultrasound receivers 54 associated with them receive. In the example, the lighter squares with the thinner puncture illustrate a first frequency of 400 kHz and the darker squares with the denser puncture represent a second frequency of 600 kHz. Consecutive lines in the Fig. 9 represent the situation at successive points in time. The points in time are spaced apart by the period Δ, which corresponds to the frequency 1 / Δ with which the ultrasonic pulses are emitted, in the example 5 kHz.

The control and evaluation device 47 ⁽⁴⁾ first emits transmission signals to the ultrasound transmitters, which essentially emit ultrasound pulses of the first frequency, which are received by the ultrasound receivers, possibly after interaction with a value document, here transmission through the value document. The ultrasonic receivers 54 form corresponding received signals, which they output to the control and evaluation device 47 ⁽ FIG. ⁴⁾ . This filters the received signals according to the ultrasonic frequency of the ultrasonic pulses and generates ultrasonic transmission data. The control and evaluation device 47 ⁽⁴⁾ then emits transmission signals to the ultrasound transmitters, which essentially emit ultrasound pulses of the second frequency, which is received by the ultrasound receivers, possibly after interaction with the value document, here transmission through the value document. The ultrasonic receivers generate corresponding received signals which they transmit to the control and evaluation device 47 ⁽⁴⁾ . This filters the received signals according to the ultrasonic frequency of the ultrasonic pulses and generates ultrasonic transmission data again. These steps are repeated so that ultrasound transmission data are used for a value document that is transported at a known speed can be determined as a function of the location. These can then be processed further as in the first exemplary embodiment.

In this way, undesired reflections of ultrasonic pulses which overlap in time with subsequent ultrasonic pulses can be separated from the desired ultrasonic pulses. In particular, interference from measurements at locations directly adjacent in the direction of transport can thus be reduced.

In a variant of this exemplary embodiment, the connections from the control and evaluation device 47 ⁽⁴⁾ to the ultrasonic transmitters 52 can be replaced by a common connection that branches off from the control and evaluation device 47 ⁽⁴⁾ to the ultrasonic transmitters 52.

A fifth exemplary embodiment differs from the third exemplary embodiment in that the ultrasound transmitters are controlled with transmission signals in such a way that these ultrasound is emitted and evaluated after receipt in a manner that combines the third and fourth exemplary embodiments in a certain way.

Compared to the third embodiment, only the device 44 ″ is replaced by a device 44 ⁽⁵⁾ (cf. Fig. 10 ). This differs from the device 44 ″ only in that the control and evaluation device 47 ″ is replaced by a control and evaluation device 47 ⁽⁵⁾ and the capacitive micromechanical ultrasonic transducers are designed for the ultrasonic frequencies used. Otherwise, the statements relating to the first exemplary embodiment also apply here accordingly.

Each of the ultrasonic transmitters emits a sequence of ultrasonic pulses in which the ultrasonic frequencies of successive ultrasonic pulses differ; in particular, they can have a first and a second ultrasonic frequency. The consequences for directly adjacent ultrasound transmitters differ, however, in that ultrasound pulses emitted by them essentially simultaneously in terms of time also each have a different ultrasound frequency.

This is in Fig. 12 illustrates that, except for the sequence of the ultrasonic frequencies Fig. 11 corresponds.

For each point in time at which pulses are to be emitted, the control and evaluation device emits transmission signals to the ultrasonic transmitters in such a way that a first group of the ultrasonic transmitters emits an ultrasonic pulse of a first predetermined ultrasonic frequency and a second group of the ultrasonic transmitters emits ultrasonic pulses of a second predetermined ultrasonic frequency; for the choice of the two ultrasonic frequencies, the criteria as described in the two preceding exemplary embodiments preferably apply. In particular, they are selected as in the two previous exemplary embodiments. As in the third exemplary embodiment, the groups are selected such that between two ultrasonic transmitters of one of the groups there is ultrasonic transmitters of the other group. For example, at time t there is a scheme similar to that in Fig. 10 corresponds. When the ultrasound is received, the ultrasound receivers each generate received signals which are fed separately to the control and evaluation device 47 ⁽⁵⁾ . This evaluates the received signals depending on the position of the ultrasonic transmitter and the ultrasonic receiver assigned to it, and filters the received signals according to the frequency of the transmitted ultrasound for the respective ultrasonic path or the ultrasonic transmitter or the respectively transmitted ultrasound.

For the next pulse in the sequence at time t + Δ, the control and evaluation device 47 ⁽⁵⁾ sends transmission signals to the ultrasonic transmitters in such a way that the first group of ultrasonic transmitters emits an ultrasonic pulse of the second predetermined ultrasonic frequency and the second group of ultrasonic transmitters emits ultrasonic pulses of the first predetermined ultrasonic frequency. The resulting pattern is in Fig. 12 shown on the second line; it corresponds to the pattern at time t, but the first and second frequencies are interchanged. This evaluates the received signals depending on the position of the ultrasonic transmitters and the ultrasonic receivers assigned to them, and filters the received signals according to the frequency of the transmitted signals for the respective ultrasonic path or the ultrasonic transmitter or the respectively transmitted ultrasound.

For the following pulse of the sequence at time t + 2Δ, the control and evaluation device 47 ⁽⁵⁾ emits transmit signals which correspond to those at time t and processes the received signals accordingly.

In these steps, the received signals of the ultrasonic receivers are processed in accordance with the frequencies of the ultrasonic pulses from the assigned ultrasonic transmitters and ultrasonic transmission data are output as a function of the location to the machine control and evaluation device.

This procedure has the advantage that when evaluating a received signal for an ultrasonic path, possible disruptive influences from ultrasound on directly adjacent ultrasonic paths and disruptive influences can be at least partially filtered out by ultrasound of pulses for adjacent ultrasound paths for the previous pulse. This variant can be used realistically through the use of capacitive micromechanical ultrasonic transducers, since these enable short pulses, a broad frequency range that can be used and a high spatial resolution across the line.

In a sixth embodiment in Fig. 13 the transport of value documents is examined immediately after the singler for the presence of overlapping value documents. The device differs from that of the first exemplary embodiment, on the one hand, in that a device 44 ⁽ FIG. ⁶⁾ for examining the transport of documents of value by means of ultrasound is arranged on the transport path 36 near the singler 22. On the other hand, the device 44 in the sensor device 38 is replaced by a conventional ultrasonic transmission sensor. Otherwise, the same reference numerals are used for components that correspond to themselves, and the statements relating to the first exemplary embodiment also apply here accordingly. Fig. 13 therefore shows only a corresponding section of the modified device in Fig. 1 .

The device 47 ⁽⁶⁾ differs from the device 47 in that the control and evaluation device 47 is replaced by a control and evaluation device 47 ⁽⁶⁾ . The control and evaluation device 47 ⁽⁶⁾ differs from the control and evaluation device 47 of the first exemplary embodiment only in that it is designed to process the received signals differently. Otherwise it is designed like the control and evaluation device of the first exemplary embodiment.

The control and evaluation device 47 ⁽⁶⁾ is more precisely designed to check the received signals for ultrasonic pulses received essentially simultaneously by the ultrasonic receivers to determine whether the level or the intensity of the received signal is lower than a predetermined threshold value which is characteristic of that received signals for an individual value document have a value above the threshold value, while those for overlapping value documents have levels below the threshold value. If the control and evaluation device 47 ^{(6) determines} for a predetermined number of ultrasound receivers that the threshold value has not been exceeded, it outputs a corresponding signal to the machine control and evaluation device 46, which indicates that at least two at least partially overlapping documents of value are being transported become.

When such a signal is received, the machine control and evaluation device can then control the transport device in such a way that the overlapping documents of value are transported into one of the output compartments which are predetermined for this purpose. In other exemplary embodiments, the transport device can also be designed in such a way that the transport path has a branch in front of the sensor device 38, on which a switch that can be controlled by actuating signals is arranged. A compartment for documents of value that are not to be processed can then be arranged at the end of the branch that does not lead to the sensor device 38. The machine control and evaluation device can then be designed to emit an actuating signal to the switch on receipt of a signal from device 47 ⁽⁵⁾ so that the overlapping documents of value are transported into the compartment and deposited there.

A seventh exemplary embodiment differs from the first exemplary embodiment only in that the device 44 is replaced by one Device 44 ⁽⁷⁾ for examining documents of value and / or the transport of documents of value. This differs from the device 44 in two ways. On the one hand, the transmitter module 51 ⁽⁷⁾ and the receiver module 53 ⁽⁷⁾ , which are otherwise designed as in the first exemplary embodiment, and thus the ultrasonic transmitter and ultrasonic receiver are arranged on the same side of the transport path 36 in the example above the transport path; so that the ultrasound remission can be examined as a value document property. On the other hand, the control and evaluation device 47 ⁽⁷⁾ differs from the control and evaluation device 47 only in that it is designed such that the received signals of the ultrasonic receivers are processed in such a way that an ultrasonic remission is determined as a function of a location on a value document .

The arrangement of the transmitter module 51 ⁽⁷⁾ and the receiver module 53 ⁽⁷⁾ and thus the ultrasonic transmitter 52 and ultrasonic receiver 54 or ultrasonic transducer is shown in FIG Figures 14 and 15 illustrates; Fig. 14 shows a roughly schematic view of the device in a direction towards the transport path, Fig. 15 a section through the device in a direction transverse to the transport path. The signal connections 49 ⁽⁷⁾ are shown in particular combined, although, as in the first exemplary embodiment, individual signal connections each connect the transmitters or receivers to the control and evaluation device.

The transmitter module 51 ⁽⁷⁾ and the receiver module 53 ⁽⁷⁾ are designed as in the first embodiment. The ultrasound transmitters 52 or their ultrasound transducers are oriented relative to the transport path 36 so that the ultrasound is inclined to the plane of the transport path or a document of value transported there, with no essential component in a direction transverse to the transport direction. The ultrasonic receiver 54 or their ultrasound transducers are arranged and aligned in such a way that they receive the ultrasound of the ultrasound transmitters 52, which was reflected on a value document, that is, their receiving direction is aligned with its direction of propagation. One ultrasonic transmitter and the associated ultrasonic receiver each form an ultrasonic path 56 ⁽⁷⁾ , which is shown in FIG Fig. 15 is symbolized by a dashed line.

In other exemplary embodiments, the ultrasonic transmitters and / or the ultrasonic receivers can each have at least two capacitive micromechanical ultrasonic transducers. In this case, the ultrasonic transducers of an ultrasonic transmitter or ultrasonic receiver are formed on the same chip. These ultrasonic transducers can be connected to the control and evaluation device 47 in such a way that they are controlled with the same transmission signals, i.e. H. the control and evaluation device emits only one transmission signal that is fed to the two ultrasonic transducers via the output or the same signal connection. Received signals from the ultrasonic transducers of an ultrasonic receiver can also be superimposed, which are fed to the control and evaluation device and received and processed by it like a received signal.

The control and evaluation device is designed to generate transmission signals for only one ultrasonic transmitter and to output them to it, or to receive and process or evaluate the superimposed reception signals from only one ultrasonic receiver.

An example of an ultrasonic transmitter 72, which has four capacitive micromechanical ultrasonic transducers 74, is shown roughly schematically Fig. 16 . The four capacitive micromechanical ultrasonic transducers 74 of the dotted Lines illustrated ultrasonic transmitters are formed the same, only partially shown chip 76, and except for their rectangular shape or the rectangular shape of the membrane on which the second electrode is formed, designed like the capacitive micromechanical ultrasonic transducers of the first embodiment. The first electrodes are jointly contacted with a conductor track (not shown); the same applies to the second electrodes, which are connected to branches of the conductor track 78. The control and evaluation device is designed to emit transmission signals which correspond to those of the first exemplary embodiment, possibly except for their level. Due to the enlarged vibrating surface of the four membranes vibrating in phase, a wider sound field and a higher sound intensity can be obtained for an ultrasonic transmitter.

In another exemplary embodiment, the ultrasonic transducers for one ultrasonic transmitter or ultrasonic receiver or ultrasonic transmitter / receiver are connected separately to the control and evaluation device via signal connections. The ultrasonic transducers of an ultrasonic transmitter can then be controlled so that they emit ultrasound at the same frequency. In this exemplary embodiment, however, the transmission signals differ in their phase.

This embodiment differs from the first embodiment in the design of the ultrasonic transmitter and that of the control and evaluation device. All other statements relating to the first exemplary embodiment apply here accordingly. In Fig. 17 an ultrasonic transmitter indicated by dashed lines is illustrated. The ultrasonic transmitter 80, which replaces an ultrasonic transmitter 52 in the first exemplary embodiment, has three identically designed capacitive micromechanical ones Ultrasonic transducers 82 which are arranged in a row and are arranged on the same chip, not shown. The ultrasonic transducers 82 are designed as in the first exemplary embodiment and are connected separately to separate conductor tracks 84, which in turn are individually connected to the control and evaluation device via separate signal connections.

The control and evaluation device differs from that of the first exemplary embodiment only in that it emits separate transmission signals for the ultrasonic transducers 82 from each of the ultrasonic transmitters 80 to the ultrasonic transducers 82, so that the ultrasonic transducers generate ultrasonic pulses with the same frequency but different phases. The phases or phase differences are selected such that the resulting sound field is more strongly bundled or focused due to the superimposition of the ultrasound of the ultrasound transducers 82 of the ultrasound transmitter. This is in Fig. 18 illustrated. This shows the sound field or the directional characteristic of the ultrasonic transducers of the ultrasonic transmitter 80, symbolized by a dashed straight line, when activated in phase by dashed lines. The corresponding sound field or the corresponding directional characteristic when actuated with different phases is shown roughly schematically by solid lines. The control and evaluation device emits transmission signals in such a way that the ultrasonic transducers emit ultrasonic pulses with different phases, so that a better directed directional characteristic or a more strongly directed or bundled sound field results.

The control and evaluation device can preferably be designed to form and output the transmission signals in such a way that the phases vary over time. For example, the transmission signals can be formed and emitted so that the directional characteristic as a function of time around one given angle is pivoted, which is in Fig. 18 is indicated by a double arrow.

In other exemplary embodiments, the ultrasonic transmitters and / or ultrasonic receivers or their capacitive micromechanical ultrasonic transducers can also be formed on at least two chips, the chips being held and contacted on a circuit carrier in such a way that their ultrasonic transducers are arranged along a line which transversely to the transport direction T. runs. This is in Fig. 19 illustrated for the case of a transmitter module in which two identically designed chips 92 with capacitive micromechanical ultrasonic transducers are arranged on a circuit carrier 90 of the module and are contacted with conductor tracks as in the first exemplary embodiment. The chips 92 are designed like the chip in the first exemplary embodiment, the explanations relating thereto and the reference symbols are also used here. The contacting and connection with the control and evaluation device takes place in such a way that the capacitive, micromechanical ultrasonic transducers of an ultrasonic transmitter or an ultrasonic receiver are formed or arranged on the same chip.

Other exemplary embodiments differ from the first exemplary embodiment in the shape and distribution of the ultrasonic transmitters and ultrasonic receivers, which in turn are each formed by a capacitive micromechanical ultrasonic transducer.

Fig. 20 shows an example in which the ultrasonic transducers 63 are arranged on a transmitter module uniformly with a small distance and therefore uniformly high resolution along a line which is longer than the extent of a value document 12 transverse to the transport direction T.

Fig. 21 In contrast, shows an example of a device in which the ultrasonic transducers 96 of a transmitter module 97 are designed with variable spacing and variable expansion. The ultrasonic transducers are again arranged in a row which is longer than the extent of a document of value 12 transversely to the transport direction T. The ultrasonic transducers in the middle of the row are arranged at a smaller distance from one another and therefore allow a correspondingly high spatial resolution of the measurement. The outer ultrasonic transducers are arranged at a greater distance from one another and have a larger sound-generating surface. The local resolution is therefore lower at the edge, but the sound level is higher.

Fig. 22 shows an example in which the ultrasonic transmitters of a transmitter module 99 are again arranged along a line transverse to the transport direction T. The ultrasonic transmitters 98 in the middle each have two capacitive ultrasonic transducers 100 formed next to one another in the transport direction, which are contacted so that they can be controlled individually with phase-shifted transmission signals of the same frequency in order to obtain the described focusing in the transport direction.

Fig. 23 shows an example in which a device for examining documents of value and / or the transport of documents of value by means of ultrasound a plurality of capacitive micromechanical ultrasonic transducers 102, which are formed on a chip 104, in a two-dimensional arrangement, in the example on the intersections of a square grid, having. Such a design is only available at low cost if the ultrasonic transducers are manufactured on a chip using methods known from micromechanics. The ultrasonic transducers can be combined individually as individual transmitters or receivers or in small groups can be controlled as a transmitter or receiver. In the latter case, in particular, a phase-shifted control of the ultrasonic transducers of one transmitter is possible.

In other exemplary embodiments, the chips can also be designed as SMT elements.

Claims (28)

1. A device for examining value documents (12) and/or the transport of value documents (12) which are transported along a specified transport path (36) in a specified transport direction, by means of ultrasound with ultrasound transmitters (52) disposed offset in a direction transverse to the transport direction for emitting, upon transmit signals, ultrasound on the transport path (36) and ultrasound receivers (54) disposed offset in a direction transverse to the transport direction for receiving ultrasound which is generated by means of the ultrasound transmitters (52) and for emitting receive signals or
   with ultrasound transmitters/receivers (52') disposed offset in a direction transverse to the transport direction for emitting ultrasound on the transport path (36) upon transmit signals and for receiving the ultrasound after interaction with at least one of the value documents (12) and for emitting receive signals,
   characterized in that
   wherein the ultrasound transmitters (52) and/or ultrasound receivers (54) respectively have at least one capacitive, micromechanical ultrasonic transducer (63), or wherein the ultrasound transmitters/receivers (52') respectively have at least one capacitive, micromechanical ultrasonic transducer (63).
2. The device according to claim 1, in which the ultrasound transmitters (52) and ultrasound receivers (54) are disposed and configured such that respectively one of the ultrasound transmitters (52) and at least one of the ultrasound receivers (54) form an ultrasound path (56; 56'; 56⁽⁷⁾) and are preferably disposed on opposing sides of the transport path (36).
3. The device according to claim 1, in which the ultrasound transmitters (52) and ultrasound receivers (54) are disposed and configured such that respectively one of the ultrasound transmitters (52) and at least one of the ultrasound receivers (54) are disposed on the same side of the transport path (36), so that ultrasound emitted by a respective one of the ultrasonic transducers (63) will be received, after interaction with one of the value documents (12) in the transport path (36), by one of the ultrasound receivers (54) and the ultrasound transmitter (52) and the ultrasound receiver (54) form an ultrasound path (56; 56'; 56⁽⁷⁾).
4. The device according to any of the preceding claims, which further has a control and evaluation device (47) which is connected with the ultrasound transmitters (52) and ultrasound receivers (54), and forms and emits transmit signals for the emitting of ultrasound by at least one of the ultrasound transmitters (52) and receives and processes receive signals of at least one of the ultrasound receivers (52) or
   which further has a control and evaluation device (47') which is connected with the ultrasound transmitters/receivers (52') and forms transmit signals for the emitting of ultrasound by at least one of the ultrasound transmitters/receivers (52') and emits these to the latter and receives and processes receive signals of the at least one of the ultrasound transmitters/ receivers (54').
5. The device according to claim 4, in which the at least one capacitive, micromechanical ultrasonic transducer (63) of at least some of the ultrasound transmitters (52) or ultrasound transmitters/receivers (52') and the control and evaluation device (47; 47') are configured such that the at least one capacitive, micromechanical ultrasonic transducer (63) of the respective ultrasound transmitters (52) or the ultrasound transmitters/receivers (52') emits ultrasonic pulses of a specified frequency and duration in dependence on transmit signals of the control and evaluation device (47; 47'), which pulses are preferably shorter than 100 milliseconds.
6. The device according to either of claims 4 or 5, in which the at least one capacitive, micromechanical ultrasonic transducer (63) of at least some of the ultrasound receivers (54) or ultrasound transmitters/receivers (52') is respectively configured such that it receives ultrasonic pulses of specified frequency and duration which are preferably shorter than 100 milliseconds and forms corresponding receive signals, and that the control and evaluation device (47; 47') is configured to receive and to process the receive signals.
7. The device according to any of the preceding claims, in which at least one of the ultrasound transmitter (52) has at least two capacitive, micromechanical ultrasonic transducers (63) and/or at least two of the ultrasound transmitters (52) respectively have at least one capacitive, micromechanical ultrasonic transducer (63), and these capacitive, micromechanical ultrasonic transducers (63) are disposed on a chip, respectively have electrodes which are contacted by conductive paths on the respective chip (58) and/or
   in which at least one of the ultrasound receivers (54) has at least two capacitive, micromechanical ultrasonic transducers (63) and/or at least two of the ultrasound receivers (54) respectively have at least one capacitive, micromechanical ultrasonic transducer (63), and these capacitive, micromechanical ultrasonic transducers (63) are disposed on a chip (58), respectively have electrodes which are contacted by conductive paths on the respective chip (58) or in which at least one of the ultrasound transmitters/receivers (52') has at least two capacitive, micromechanical ultrasonic transducers (63) and/or at least two of the ultrasound transmitters/receivers respectively have at least one capacitive, micromechanical ultrasonic transducer (63), and these capacitive, micromechanical ultrasonic transducers (63) are disposed on a chip (58), and respectively have electrodes which are contacted by conductive paths on the respective chip (58).
8. The device according to any of the preceding claims, in which adjacent ones of the capacitive, micromechanical ultrasonic transducers (63) configured on a chip (58) have a distance between 100 µm and 10 mm in the transport direction and/or a distance between 100 µm and 10 mm transverse to the transport.
9. The device according to any of the preceding claims, in which at least one of the capacitive, micromechanical ultrasonic transducers (63) has an extent between 100 µm and 10 mm in the transport direction and/or an extent between 100 µm and 10 mm transverse to the transport direction.
10. The device according to claim 4 or any of claims 5 to 9 in connection with claim 4, in which the control and evaluation device (47; 47') is configured to emit transmit signals to at least two different, preferably adjacent ones of the ultrasound transmitters (52) or ultrasound transmitters/receivers (52') preferably at the same time, so that these emit ultrasound with different frequency or pulses of ultrasound with different frequency, and to receive and to process, in particular to accordingly filter, receive signals of the ultrasound receiver (54) forming an ultrasound path (56; 56'; 56⁽⁷⁾) with the respective ultrasound transmitter (52) or of the ultrasound transmitter/receiver (47').
11. The device according to claim 4 or any of claims 5 to 10 in connection with claim 4, in which the control and evaluation device (47; 47') is configured to emit transmit signals to at least one of the ultrasound transmitters (52) or the ultrasound transmitters/receivers (52') such that this emits a sequence of ultrasonic pulses from which at least two successive ones have a different frequency, and to receive and process receive signals of the ultrasound receiver (54) associated with the respective ultrasound transmitter (52) or of the ultrasound transmitter/receiver (52'), preferably to filter these according to the frequencies or the succession of the frequencies of the emitted pulses.
12. The device according to claim 4 or any of claims 5 to 11 in connection with claim 4, in which at least one of the ultrasound transmitters (52) or at least one of the ultrasound transmitters/receivers (52') has at least two capacitive, micromechanical ultrasonic transducers (63) and the ultrasonic transducers (63) of the at least one ultrasound transmitter (52) or ultrasound receiver (54) or ultrasound transmitter/receiver (52') are connected with the control and evaluation device (47; 47') such and the control and evaluation device (47; 47') is configured such that this emits transmit signals to the ultrasonic transducers (63) so that these emit ultrasound with the same frequency, or that this processes the receive signals jointly for a same frequency.
13. The device according to claim 4 or any of claims 5 to 12 in connection with claim 4, in which the control and evaluation device (47; 47') is configured such that it emits such transmit signals to the capacitive, micromechanical ultrasonic transducers (63) that these emit ultrasound with the same frequency and different phase.
14. The device according to claim 4 or any of claims 5 to 13 in connection with claim 4, in which the control and evaluation device (47; 47') is configured to ascertain from the receive signals upon processing these at least one value which represents the weight per unit area and/or the thickness of a value document (12).
15. The device according to claim 4 or any of claims 5 to 14 in connection with claim 4, in which the control and evaluation device (47; 47') is configured to ascertain from the receive signals upon processing these a local weight per unit area-profile or thickness profile.
16. The device according to claim 4 or any of claims 5 to 15 in connection with claim 4, in which the control and evaluation device (47; 47') is configured to ascertain upon processing the receive signals whether a value document (12) for which receive signals were received was transported as a single value document (12) or at least partly overlapping with another value document (12), and upon ascertaining at least partly overlapping value documents (12) to emit a signal representing a result of the ascertaining.
17. The device according to claim 4 or any of claims 5 to 16 in connection with claim 4, in which the control and evaluation device (47; 47') is configured to recognize, upon processing the receive signals employing the receive signals, edges, preferably leading edges or trailing edges, of a transported value document (12), and wherein the control and evaluation device (47; 47') is preferably configured to recognize upon processing the receive signals whether and/or when at least one specified edge, preferably the leading edge in the transport direction and/or the trailing edge in the transport direction, of a value document (12) passes a specified location at the transport path (36), and/or to recognize the position thereof and to preferably emit thereupon a corresponding signal.
18. An apparatus for processing value documents (12) comprising a feeding device (14) for accepting value documents (12) to be processed,
    an output device for outputting or accepting the processed value documents (12), a transport device (18) for transporting the value documents (12) from the feeding device (14) along a transport path (36) to the output device and
    with at least one device, disposed in the region of a portion of the transport path (36), for examining the value documents (12) and/or the transport of the value documents (12) which are transported along the transport path (36), according to any of claims 1 to 17.
19. A method for examining value documents (12) and/or for monitoring the transport of value documents (12) by means of ultrasound, in which
    by means of at least one ultrasound transmitter (52) ultrasound is emitted, upon transmit signals, on a value document (12) transported along a transport path (36) and the ultrasound thereupon emanating from the value document (12) is received by means of at least one ultrasound receiver (54) and receive signals are formed, or by means of at least one ultrasound transmitter/receiver (52') ultrasound is emitted, upon transmit signals, on a value document (12) transported along a transport path (36) the ultrasound thereupon emanating from the value document (12) is received by means of the at least one ultrasound transmitter/receiver (52') and receive signals are formed,
    characterized in that
    the at least one ultrasound transmitter (52) and/or at least one ultrasound receiver (54) or the at least one ultrasound transmitter/receiver (52') have at least one capacitive, micromechanical ultrasonic transducer (63).
20. The method according to claim 19, in which a device according to any of the preceding claims is employed and the ultrasound transmitters (52) and ultrasound receivers (54) or ultrasound transmitters/receivers (52') of the device are employed as the at least one ultrasound transmitter (52) and the at least one ultrasound receiver (54) or the ultrasound transmitters/receivers (52') as the at least one ultrasound transmitter/receiver (52'), and transmit signals are emitted to the at least one ultrasound transmitter (52) or the at least one ultrasound transmitter/receiver (52') which thereupon emits ultrasound, and upon receiving the formed ultrasound receive signals of the at least one ultrasound receiver (54) or ultrasound transmitter/receiver (52') are received and evaluated.
21. The method according to claim 19 or 20, in which the at least one capacitive, micromechanical ultrasonic transducer (63) of at least some of the ultrasound transmitters (52) or ultrasound transmitters/receivers (52') is configured such and transmit signals are formed and emitted such that the at least one capacitive, micromechanical ultrasonic transducer (63) of the respective ultrasound transmitters (52) or the ultrasound transmitter/receiver (52') emits ultrasonic pulses of a specified frequency and duration in dependence on the transmit signals of the control and evaluation device (47; 47'), which pulses are preferably shorter than 100 milliseconds.
22. The method according to any of claims 19 to 21, in which the at least one capacitive, micromechanical ultrasonic transducer (63) of at least some of the ultrasound receivers (54) or ultrasound transmitters/receivers (52') is respectively configured such that it receives ultrasonic pulses of specified frequency and duration which are preferably shorter than 100 milliseconds and forms corresponding receive signals, and the receive signals are received and processed.
23. The method according to any of claims 19 to 22, in which transmit signals are emitted to at least two different, preferably adjacent ones of the ultrasound transmitters (52) or ultrasound transmitters/receivers (52'), so that these emit ultrasound with different frequency or pulses of ultrasound with different frequency, and receive signals of the ultrasound receiver (54) forming an ultrasound path (56; 56'; 56⁽⁷⁾) with the respective ultrasound transmitter (52) or of the ultrasound transmitter/receiver (52') are received and processed, in particular accordingly filtered.
24. The method according to any of claims 19 to 23, in which at least one of the ultrasound transmitters (52) is controlled with transmit signals such that this emits a sequence of ultrasonic pulses from which at least two successive ones have a different frequency, and receive signals of the ultrasound receiver (54) associated with the respective ultrasound transmitter (52) or of the ultrasound transmitter/receiver (52') are received and processed, preferably filtered according to the frequencies or the succession of the frequencies of the emitted pulses.
25. The method according to any of claims 19 to 24, in which at least one of the ultrasound transmitters (52) and/or ultrasound receivers (54) or ultrasound transmitters/receivers (52') has at least two capacitive, micromechanical ultrasonic transducers (63), and in which transmit signals are emitted to these capacitive, micromechanical ultrasonic transducers (63) preferably such that these emit ultrasound with the same frequency, or the receive signals are evaluated for a specified same frequency.
26. The method according to any of claims 19 to 25, in which there is ascertained from the receive signals, preferably by means of an evaluation device or the control and evaluation device (47; 47'), at least one value which represents the weight per unit area and/or the thickness of the value document (12).
27. The method according to any of claims 19 to 26, in which there are ascertained from the receive signals, preferably by means of an evaluation device or the control and evaluation device (47; 47'), values which represent the weight per unit area and/or the thickness in dependence on the location.
28. The method according to any of claims 19 to 27, in which upon processing the receive signals these are employed to recognize whether and/or when at least one specified edge, preferably the leading edge in the transport direction and/or the trailing edge in the transport direction, of a value document (12) passes a specified location, and/or to recognize the position thereof.

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