An apparatus and a corresponding method for checking value documents, involves at least one first sensor configured to detect electromagnetic radiation reflected and/or transmitted by a value document and to convert the radiation into corresponding first sensor signals. At least one second sensor is configured to detect sound waves reflected and/or transmitted by the value document and to convert the sound waves into corresponding second sensor signals, and an evaluation device configured to determine a first area value which characterizes a first area of the value document on the basis of the first sensor signals, to determine a second area value which characterizes a second area of the value document on the basis of the second sensor signals, and to infer a possible identification marking of the value document with a marking ink on the basis of the first and second area value.

An apparatus and a corresponding method for checking value documents, involves at least one first sensor configured to detect electromagnetic radiation reflected and/or transmitted by a value document and to convert the radiation into corresponding first sensor signals. At least one second sensor is configured to detect sound waves reflected and/or transmitted by the value document and to convert the sound waves into corresponding second sensor signals, and an evaluation device configured to determine a first area value which characterizes a first area of the value document on the basis of the first sensor signals, to determine a second area value which characterizes a second area of the value document on the basis of the second sensor signals, and to infer a possible identification marking of the value document with a marking ink on the basis of the first and second area value.

According to one embodiment, a transducer includes first structure sections and second structure sections. The first structure sections are spaced from each other in a first direction. Part of each of the first structure sections is fixed. The each of the first structure sections includes a first membrane part, a first piezoelectric part, a first conductive part, and a first electrode. The second structure sections are spaced from each other in the first direction. Part of each of the second structure sections is fixed. The each of the second structure sections includes a second membrane part, a second piezoelectric part, a second conductive part, and a second electrode. The second structure sections are spaced from the first structure sections in the first direction. Pitch along the first direction of the second structure sections is shorter than pitch along the first direction of the first structure sections.

According to one embodiment, a transducer includes first structure sections and second structure sections. The first structure sections are spaced from each other in a first direction. Part of each of the first structure sections is fixed. The each of the first structure sections includes a first membrane part, a first piezoelectric part, a first conductive part, and a first electrode. The second structure sections are spaced from each other in the first direction. Part of each of the second structure sections is fixed. The each of the second structure sections includes a second membrane part, a second piezoelectric part, a second conductive part, and a second electrode. The second structure sections are spaced from the first structure sections in the first direction. Pitch along the first direction of the second structure sections is shorter than pitch along the first direction of the first structure sections.

A method for examining a value document includes emitting ultrasonic pulses onto several locations on the value document. An echo pulse arises by reflection of at least a portion of a respective ultrasonic pulse at the value document. The echo pulses are received while forming echo values, and from the echo values at least a characteristic value is established as to the wrinkledness of the value document. As apparatus is provided for carrying out the method.

A method for examining a value document includes emitting ultrasonic pulses onto several locations on the value document. An echo pulse arises by reflection of at least a portion of a respective ultrasonic pulse at the value document. The echo pulses are received while forming echo values, and from the echo values at least a characteristic value is established as to the wrinkledness of the value document. As apparatus is provided for carrying out the method.

Described is a device for examining value documents and/or the transport of value documents which are transported along a specified transport path in a specified transport direction, by means of ultrasound with ultrasound transmitters disposed offset in a direction transverse to the transport direction for emitting, upon transmit signals, ultrasound on the transport path and ultrasound receivers disposed offset in a direction transverse to the transport direction for receiving ultrasound which is generated by means of the ultrasound transmitters, and for emitting receive signals, the ultrasound transmitters and/or ultrasound receivers respectively having at least one capacitive, micromechanical ultrasonic transducer.

Described is a device for examining value documents and/or the transport of value documents which are transported along a specified transport path in a specified transport direction, by means of ultrasound with ultrasound transmitters disposed offset in a direction transverse to the transport direction for emitting, upon transmit signals, ultrasound on the transport path and ultrasound receivers disposed offset in a direction transverse to the transport direction for receiving ultrasound which is generated by means of the ultrasound transmitters, and for emitting receive signals, the ultrasound transmitters and/or ultrasound receivers respectively having at least one capacitive, micromechanical ultrasonic transducer.

A method and apparatus are disclosed for determining if an item of media is invalid. The method includes providing an ultrasound image of an item of media, determining a plurality of regions of the image that satisfy a pre-determined condition and determining that an item of media is invalid if the location of said regions satisfies a pre-determined condition.

A method and apparatus are disclosed for determining if an item of media is invalid. The method includes providing an ultrasound image of an item of media, determining a plurality of regions of the image that satisfy a pre-determined condition and determining that an item of media is invalid if the location of said regions satisfies a pre-determined condition.