EP2229663A1

EP2229663A1 - Sensor for checking valuable documents

Info

Publication number: EP2229663A1
Application number: EP08869219A
Authority: EP
Inventors: Joseph Lohner
Original assignee: Giesecke and Devrient GmbH
Current assignee: Giesecke and Devrient GmbH
Priority date: 2007-12-21
Filing date: 2008-12-15
Publication date: 2010-09-22
Also published as: US8605267B2; RU2482543C2; CN101889298B; US20100271619A1; CN101889298A; RU2010129551A; WO2009083126A1; DE102007062122A1

Abstract

In valuable document processing machines, valuable documents, for example banknotes, cheques, etc., are conveyed along one or more sensors by a transport system. The banknotes guided past the sensors at least temporarily touch the sensor surface. In order to improve transport, the sensor surface, past which the banknotes are transported, is provided with a multiplicity of elevations or depressions. The structured sensor surface reduces the friction between the sensor surface and the valuable document being transported past said sensor, with the result that transport of the valuable document is stabilized and the susceptibility to jams is reduced.

Description

Sensor for checking value documents

The invention relates to a sensor for checking documents of value, such as bank notes, as well as a device in which this sensor is installed, such as a bank note processing machine, an ATM, a payment device, etc.

In banknote processing machines, banknotes are checked for their denomination, currency, authenticity or their condition by means of sensors, for example. For this purpose, the banknotes are transported by a transport system and thereby pass through a sensor path with one or more sensors. The banknotes are transported substantially parallel to the banknote facing surface of the sensor. The sensor surface is usually a flat surface, which has only a few recesses, eg for measuring heads or windows, but without raised or recessed areas. In some sensors, the banknotes transported past slide at least temporarily on the sensor surface. However, as the banknotes slide along, the surface of the sensor becomes dirty and worn over time. In addition, touches of the banknotes take place randomly and undefined, which leads to an uneasy transport, for example, to the fluttering of the banknotes. This has a disadvantageous effect on the reproducibility of the measurement results. In order to minimize the friction between the banknote and the sensor surface, the sensor surface is therefore usually designed as flat as possible. Another disadvantage of contacting transport is the electrostatic charge of the bill due to the friction between the bill and the sensor surface. For these reasons, the transport of banknotes past the known sensors repeatedly leads to congestion in banknote transport. It is therefore an object of the invention to achieve a trouble-free transport of value documents, in particular banknotes, along the sensors.

This object is solved by the subject matters of the independent claims.

The invention is based on the idea of providing the sensor surface, along which the documents of value are transported past the sensor, with a structure comprising a multiplicity of elevations or a plurality of depressions. As surveys in the sense of the application convex sites of the sensor surface and referred to as depressions concave points of the sensor surface. For example, the sensor surface has one or more structured sections, each having a plurality of elevations or a plurality of depressions. In comparison with transport along a flat sensor surface, the pressure force on the sensor surface and thus also the frictional force between the document of value and the sensor surface are reduced during transport of a value document along the sensor surface structured in accordance with the invention.

It is assumed that the flow of the air displaced by the value document changes due to the structure of the sensor surface according to the invention, and at least temporary air cushions arise between the value document and the sensor surface. These air cushions cause a force on the document of value, which counteracts the pressure force on the sensor surface. To achieve this effect, there are many possible embodiments of the sensor surface according to the invention. This applies both to the height or depth and the lateral extent of the elevations or depressions, which are introduced into the sensor surface, as well as the shape and the arrangement of the elevations or depressions. Which of these However, sensor surface designs are best suited for a particular transport task, but will depend on the particular transport conditions. For example, the formation of the air cushion takes place as a function of the size of the value document, as a function of the transport speed of the value document and as a function of the distance between the value document and the sensor surface. These transport parameters span a large range of values in the usual value-document transport tasks. Therefore, no optimum design of the sensor surface can be defined, which leads to the desired effect for all transport tasks. The finding of the structures of the sensor surface which are most suitable for the respective application must therefore ultimately be left to the person skilled in the art, who will determine this within the scope of corresponding tests.

Preferably, the elevations or depressions have a rounded surface. The elevations preferably have a convex shape, in particular a knob-like shape or the shape of webs which run approximately parallel to the transport direction of the document of value. The depressions preferably have a concave shape, in particular a multicell-like shape or the shape of trenches which run approximately parallel to the transport direction of the document of value. In addition, all protrusions or depressions within one or each structured portion preferably have approximately the same shape and / or the same lateral extent and / or the same height or depth. Moreover, the protrusions or depressions within one or each of the structured portions of the sensor surface may form a regular structure. For example, all elevations or depressions within one or each of the structured sections form a two-dimensional grid, which can be defined by an elementary cell and a grid base which comprises one or more elevations or one or more depressions. stands. The unit cell has, for example, the geometric shape of a square or a rectangle or a parallelogram or a polygon. However, the structured sections, in particular the regular structures or also the two-dimensional grid, can be interrupted by recesses in the sensor surface and / or by flat sections.

In a preferred embodiment, the elevations perpendicular to the transport plane of the documents of value have a height of 0.05 mm to 2 mm, more preferably from 0.1 mm to 1 mm, in particular from 0.1 mm to 0.5 mm. Alternatively, the depressions perpendicular to the transport plane of the documents of value have a height of 0.05 mm to 2 mm, particularly preferably from 0.1 mm to 1 mm, in particular from 0.1 mm to 0.5 mm. The lateral dimensions of the elevations or depressions, which have these parallel to the transport plane of the value documents, are greater than the height or depth of the elevations or depressions. The lateral extent in the transport direction of the value documents is referred to as the length of the elevation or depression, the lateral extent perpendicular to the transport direction as its width. Preferably, the length and / or the width of the elevations or depressions is at least twice as large, in particular at least 5 times as great as their height or depth. In addition, the length of the elevations or depressions is preferably greater than their width. The length and / or the width of the elevations or depressions may be, for example, at least 0.5 mm, preferably at least 2 mm.

The width of the elevations or depressions perpendicular to the transport direction and the distances of adjacent elevations or depressions perpendicular to the transport direction are selected so that the value document extends perpendicular to the transport direction over a plurality of elevations or depressions. Preferably, the value document extends vertically to the transport direction over at least two, preferably over at least 5 elevations or depressions. The dimensions mentioned below can be used, for example, in a sensor for checking documents of value, in particular banknotes, whose length is usually between 100 mm and 200 mm and whose width is usually between 50 mm and 100 mm: The width and / or the distances of the Elevations or depressions perpendicular to the transport direction are, for example, a maximum of 20 mm, in particular a maximum of 10 mm, for example a maximum of 5 mm. Also parallel to the transport direction of the documents of value, the distances of immediately adjacent elevations or depressions are preferably not more than 20 mm, in particular not more than 10 mm, particularly preferably not more than 5 mm. In particularly preferred embodiments, the distances of immediately adjacent elevations or depressions are parallel and / or perpendicular to the transport direction 0 mm to 2 mm.

In a first embodiment, the sensor according to the invention is a sensor block in which a plurality of sensor chambers are contained. In each of the sensor chambers, a measuring head and / or measuring elements for checking the value documents can be arranged, which are transported along the surface of the sensor block over. This sensor block surface is formed by sensor covers which cover the top of the sensor chambers (facing the value documents) and by further covers which cover the areas of the top side of the sensor block lying between and beside the sensor chambers. The sensor block surface may comprise one or more sections structured according to the invention, which are or are incorporated in the sensor covers and / or in the further covers.

In a second embodiment, the sensor according to the invention has a housing with a housing surface which forms the sensor surface and which is an integral part of the case. Along the housing surface, the value documents are transported past the sensor. At least one section structured in accordance with the invention is introduced into the housing surface.

In a third embodiment, the sensor according to the invention has a housing body on whose (the value documents facing) upper side at least one front element is arranged, whose surface forms the sensor surface. At least one structured section is introduced into the surface of at least one of the front elements.

The sensor surface having the structured portion (s) may, in particular, be a front element or a sensor cover or a further cover of a sensor block or a housing surface. The sensor cover structured in accordance with the invention and / or the further cover and / or the housing surface and / or the front element may have one or more recesses. In these recesses, measuring heads and / or transport elements, e.g. Transport rollers, and / or windows may be arranged to be transmitted by the measuring signals of the sensor. The recesses may also be open, wherein measuring heads or measuring elements can be arranged in or immediately below the recess. The sensor cover and / or the housing surface and / or the front element can be translucent and, for example, have one or more flat sections without elevations or depressions through which optical measuring signals of the sensor are transmitted.

In the examples mentioned, the front elements or the sensor covers or the further covers of the sensor block close the housing body or the sensor block on its side facing the value document Top off. Alternatively, the front elements or the sensor covers or the other covers can also be applied to the top of a dust-tight sealed housing from the outset. In this case, the front elements or the sensor covers or the other covers can advantageously be removed from the housing without the penetration of dust. When changing worn sensor surfaces, the measuring elements then remain dust-tight encapsulated in the housing. The front elements or the sensor covers or the further covers of the sensor block can be fastened to the respective housing or sensor block with the aid of the usual types of fastening, eg by snap connection, by wedging, by clamping, by means of screws or by gluing, for a permanent attachment even by pressing or by fusion.

The production of the sensor surface according to the invention can be done for example by injection molding, embossing or deep drawing. As materials for the sensor surface, in which the elevations or depressions are introduced, plastics, metal or glass can be used. Preferably, the sensor surface, in particular the sensor cover and / or the further cover and / or the housing surface and / or the front element has a wear-resistant, eg glass or carbon fiber reinforced plastic. The plastic preferably has a low coefficient of friction and / or is electrically conductive in order to avoid electrical charges due to the friction of the value document. In addition, the plastic used can also be transparent to visible light and / or light in IR, UV. Alternatively, the sensor surface can also comprise hardened or hard-coated aluminum or a metal sheet, for example of aluminum, magnesium or stainless steel. In order to achieve the mentioned properties of the sensor surface, the sensor surface can also be coated with suitable materials. In addition to the sensor itself, another aspect of the invention is the sensor component which forms the sensor surface of the sensor structured according to the invention. The sensor component, which has on its surface the plurality of elevations or depressions, may be a sensor cover of a sensor block or a further cover of a sensor block or a front element for covering a housing body or a complete sensor housing or a partial housing of the sensor. The sensor component is designed to be assembled with further sensor components to form a complete sensor.

The invention also relates to a device for checking value documents which has one or more sensors according to the invention, for example a processing machine for documents of value, in particular for banknotes, coupons, vouchers, vouchers or checks. The processing machine can be a checking and sorting device or else an ATM, a deposit device, a banknote recycling device or a payment device. In the apparatus, a plurality of sensors may be provided on one or both sides of the transport path of the value documents, e.g. be arranged opposite each other. Both opposing sensors can have a sensor surface structured in accordance with the invention. Alternatively, in comparison to a sensor according to the invention, it is also possible to arrange a guide element whose surface is arranged like a sensor surface structured in accordance with the invention. The arrangement of the elevations or depressions of the oppositely structured surfaces can be mirror-inverted with respect to one another or offset from one another.

Moreover, the invention also relates to a method for checking value documents, in which the value documents, for example by means of belts and / or with the aid of rollers on a sensor according to the invention to be transported over. The transport speed of the value documents is usually in the range between 0.1 m / s and 10 m / s. When transporting the value document along the sensor surface, at least temporarily, air cushions are formed between the value document and the sensor surface.

When transporting the value documents by means of belts, the belts exert a pressure force on the value document in the direction of the sensor surface so that the value documents touch the sensor surface at least temporarily. As an alternative to this, the value documents can also be transported without belts and only along the sensor surface by means of rollers, which are arranged on both sides of the transport plane of the value documents and ensure a permanent clamping of the value documents. The distance between the value document and the sensor surface is usually in the range between 1 mm and 5 mm. Depending on the distance between the document of value and the sensor surface, a more or less strong and frequent contact between the sensor surface and the documents of value may also occur in this case. The sensor surface structured in accordance with the invention can be used for both of these types of transport, wherein the specific embodiment of the sensor surface is to be selected as a function of the respective mode of transport, in particular of transport speed and distance.

The transport direction of the value documents defines at the sensors, which are arranged along the transport path of the value document, respectively an input side, on which the value document is guided into the detection range of the sensor, and an output side, on which the value document is led out of the detection range. The front element or the sensor cover or the further cover or the housing is preferably designed and arranged such that it is attached to the value document. facing surface, beveled on the input side and / or beveled on the output side. As a result of these chamfers, edges which are obtuse and do not impair the transport are formed in the immediate vicinity of the transported value document.

The sensors according to the invention can e.g. mechanical sensors, magnetic sensors, capacitive sensors, ultrasonic sensors or even photosensors, which are used for optical testing of the value documents in UV, VIS or IR.

The invention will be described by way of example with reference to the accompanying drawings.

Show it:

1 is a perspective view of three adjacent sensors, each with a front element on the sensor surface, Fig. 2 shows a sectional view of the transport channel between a sensor and a guide element arranged opposite, Fig. 3a perspective view of a front element for a plurality of measuring heads,

3 b, sectional view through the front element from FIG. 3 a, with the measuring heads,

4 a side view of a sensor block with two sensor chambers, FIG. 4 b perspective view of a further cover for the sensor block from FIG. 4 a,

Fig. 5 shows a sectional view through a housing with window, and Fig. 6a-e schematic representation of various regular structures of the sensor surface in plan view. FIG. 1 shows a perspective view of three adjacent sensors 1, which are designed for checking value documents 5 and which are arranged on one side of a transport path of the value documents 5. The value documents 5 are transported for example by roller transport parallel to the surface of the sensors 1, for example in the direction indicated by the arrow transport direction W. Opposite to the sensors 1 further sensors can be arranged, which also has a structured sensor surface with a plurality of elevations 4 or depressions can have. The sensors 1 each have a housing body 2, on whose upper side a front element 7 is arranged. To improve the value document transport in the transition region between the sensors 1, the front elements 7 are each provided with a comb structure on its input side and on its output side. The comb structures of the adjacent front elements 7 are preferably designed such that they engage one another, ie that teeth of one front element 7 can be arranged at least partially in gaps of the adjacent front element 7 and vice versa. In addition, recesses 8 are introduced into the front elements 7, in which transport rollers 9 and windows 6 are arranged, through which the sensors 1 can detect measurement signals. In the surface of the front elements 7, a regular structure composed of a plurality of elevations 4 is introduced outside the recesses 8 and the comb structure, forming a section 16 of the front element 7 structured in accordance with the invention.

The value documents 5 are guided along the sensor surface, for example with the aid of transport rollers 9, through a transport channel which is formed between the sensor and an oppositely arranged guide element 17, cf. FIG. 2. The guide element 17 can likewise have a structured section 16 made up of a multiplicity of elevations 4 or depressions 3. The surface of the guide element 17 can be produced analogously to the invention. be formed to the invention sensor surface of the opposite sensor. The elevations or depressions of the two opposing surfaces can either be arranged in mirror image relative to one another, as shown in FIG. 2, or offset relative to one another in the transport direction and / or perpendicular to the transport direction. In the exemplary embodiment of FIG. 2, the sensor surface is formed by a front element 13 of an optical sensor, which is transparent at least for visible light and for IR. Within the optical sensor, measuring elements 20 are arranged, which emit light for illuminating the value document 5 and detect light emitted back from the value document 5, in particular light sources or light source arrays and / or detectors or detector arrays. In order not to impair the optical beam path, the front element 13 has a flat section 26 in which the section 16 structured according to the invention is interrupted and through which the light is transmitted without disturbing deflection. Alternatively, in comparison to the optical sensor, on the other side of the transport channel instead of the guide element 17, a further optical sensor and / or a further light source and / or a further detector may be arranged which are used to measure light transmitted by the value document 5.

FIGS. 3 a and 3 b show a further exemplary embodiment of a front element 11, which is designed to be arranged on a housing body, in which a plurality of measuring heads 10, 18 are arranged. The front element 11 has a structured portion according to the invention, which extends over the entire front element 11 and has a plurality of recesses 3 of depth T, and three recesses 8. The large recess serves to receive a measuring head 10, for example, for measuring magnetic Properties of the value document may be formed. The two smaller recesses 8 remain unlocked, so that the measurement signals of the immediately below arranged measuring heads 18 be transmitted through the recesses. The measuring heads 18 are, for example, ultrasound measuring heads with which the ultrasound reflection or the ultrasound transmission of the value documents 5 transported past is detected.

In a further exemplary embodiment, the sensor surface structured in accordance with the invention is a surface of a sensor block 25, cf. Figure 4a and Figure 4b. The sensor block contains two sensor chambers 19, one for receiving optical measuring elements 20 and one for receiving a measuring head 10. The left sensor chamber 19 with the optical measuring elements 20 is closed by a transparent plastic cover 13, in the surface of which an inventively structured section 16 is introduced, which is interrupted in the region of the optical measuring elements 20 by a flat portion 26. At the top of the right sensor chamber 19, a cover 12 is arranged, in the recess of a measuring head 10 is arranged. On the surface of the sensor block 25 also two further covers 14 are arranged, which are also provided with structured portions 16, see. FIG. 4b. The further covers 14 have recesses 8 through which transport rollers 9 protrude out of the sensor block 25 and into the transport channel of the value documents 5. Both the sensor covers 12, 13 and the further covers 14 may be e.g. be fastened by means of clamping lugs 15 on the sensor block 25. The further cover 14 shown in FIG. 4b has four sections 16 structured in accordance with the invention. The sensor covers 12, 13 may also have one or more sections 16 structured according to the invention.

FIG. 5 shows another exemplary embodiment of a sensor according to the invention, which has a housing 21, in the surface of which one or more sections 16 structured according to the invention are introduced. The housing 21 may for example be made of injection molding, wherein the invention proper elevations or depressions are generated by the injection mold itself. At the top of the sensor, a window 6 can be arranged, through which the measurement signals of the optical measuring elements 20 of the sensor are transmitted.

FIG. 6 shows schematically some embodiments of sensor surfaces structured according to the invention. The elevations 4 or depressions 3 are outlined by the boundary line of their base. In each subfigure 6a-6e, a circular section of a regular structure of protrusions or depressions is shown, which extends over a structured section 16, e.g. over the entire length of the sensor cover 12, 13 or the front element 7, 11 or the further cover 14 or the housing 21. The regular structure may be interrupted, e.g. through recesses or even sections. The shown regular structures are selected merely by way of example and are by no means limitative with regard to the dimensions, size ratios, spacings and arrangement of the elevations 4 or depressions 3, which may have the sensor surface according to the invention.

Many of the inventive regular structures of the sensor surface can be defined in analogy to crystal lattices by an elementary cell, at the corners of each one grid base is arranged. The grid base may consist of a survey 4 or a recess 3, but it may also consist of several surveys 4 or depressions 3. The unit cell may e.g. have the geometric shape of a polygon. The base of these elevations or depressions may be, for example, circular or oval or elliptical.

FIG. 6 a shows a regular structure of elevations 4 whose elementary cell is a parallelogram (dotted line). The grid In this case, there is only one elevation 4. Alternatively, the regular structure from FIG. 6a may of course also consist of depressions 3 instead of the elevations 4. In order to illustrate the dimensions of the individual elevations 4 or depressions 3, their length L is drawn in FIG. 6 a, which has these in the transport direction of the value document (arrow) and their width B, which is the elevation or depression perpendicular to the transport direction (parallel to the transport direction) Transport level). The length L of the elevations 4 or depressions 3 in this example is about 7 mm and is greater than the width B, which in this example is about 3 mm. FIG. 6 b shows an alternative embodiment of a regular structure which has a rectangular unit cell (dotted line) and also contains only one elevation 4 or depression 3 as a grid base. The regular structure of FIG. 6c is defined by a hexagon (dotted line) as elementary cell and also contains only one elevation 4 or depression 3 as a grid base. FIG. 6 d shows a regular structure which is defined by a parallelogram as an elementary cell (dotted line) but has a lattice base comprising two elevations 4 or depressions 3. The elevations or depressions of the regular structure from FIG. 6 e have the form of webs or trenches whose length L in the transport direction is much greater than their width B perpendicular to the transport direction. The webs or trenches may extend in the transport direction over the entire structured portion 16, for example over the entire length of the sensor cover 12, 13 or the front element 7, 11 or the further cover 14 or the housing 21st

Claims

Patent claims

1. A sensor for checking documents of value (5), in particular of banknotes, which has a sensor surface and which is designed for checking value documents which are transported past the sensor in a transport direction (W) along the sensor surface, characterized in that the Sensor surface at least one structured portion (16) containing a plurality of elevations (4) or a plurality of recesses (3).

2. Sensor according to one or more of the preceding claims, characterized in that the elevations (4) or depressions (3) have a rounded surface.

3. Sensor according to one or more of the preceding claims, characterized in that the elevations (4) have a convex, in particular knob-like shape or the shape of webs which extend approximately parallel to the transport direction of the document of value.

4. Sensor according to one or more of the preceding claims, characterized in that the recesses (3) have a concave shape, in particular a trough-like shape or the shape of trenches which extend approximately parallel to the transport direction of the document of value.

5. Sensor according to one or more of the preceding claims, characterized in that all elevations or depressions within the structured portion (16) have approximately the same shape and / or lateral extent (B, L) and / or height (H) or depth ( T), wherein the Variety of surveys (4) or depressions (3) within the structured portion (16) preferably form a regular structure.

6. Sensor according to one or more of the preceding claims, characterized in that all elevations (4) or depressions (3) within the structured portion (16) form a two-dimensional grid, which can be defined by a unit cell and a grid base, wherein the unit cell preferably has the geometric shape of a square, a rectangle, a parallelogram or a polygon and wherein the grid base consists of exactly one elevation (4) or depression (3) or multiple elevations (4) or multiple wells (3) ,

7. Sensor according to one or more of the preceding claims, characterized in that the elevations (4) has a height (H) of 0.05 mm to 2 mm, preferably from 0.1 mm to 1 mm, in particular of 0.1 mm to 0.5 mm or that the recesses (3) have a depth (T) of 0.05 mm to 2 mm, preferably from 0.1 mm to 1 mm, in particular from 0.1 mm to 0.5 mm.

8. Sensor according to one or more of the preceding claims, characterized in that the lateral extent (L) of the elevations (4) or depressions (3) parallel to the transport direction and / or the lateral extent (B) of the elevations (4) or Recesses (3) perpendicular to the transport direction is at least twice as large, in particular at least 5 times as large as the height of the elevations (4) or the depth of the recesses (3).

9. Sensor according to one or more of the preceding claims, characterized in that the lateral extent (L) of the elevations (4) or the depressions (3) parallel to the transport direction of the value document Elements is larger than the lateral extent (B) perpendicular to the transport direction, wherein the elevations (4) or the depressions parallel to the transport direction preferably have an extent (L) of at least 0.5 mm, in particular of at least 2 mm.

10. Sensor according to one or more of the preceding claims, characterized in that the elevations (4) or depressions (3) perpendicular to the transport direction of the documents of value have an extension (B) of at least 0.5 mm, in particular of at least 2 mm and of not more than 20 mm, preferably not more than 10 mm, in particular not more than 5 mm.

11. Sensor according to one or more of the preceding claims, characterized in that the distances between immediately adjacent elevations (4) or depressions (3) parallel and / or perpendicular to the transport direction are at most 10 mm, preferably at most 5 mm, in particular 0 mm up to 2 mm.

12. Sensor according to one or more of the preceding claims, characterized in that the sensor is a sensor block (25) in which a plurality of sensor chambers (19) are contained and which has a sensor block surface, along which the value documents (5) be transported past the sensor block, wherein the sensor block surface has at least one structured portion (16).

13. Sensor according to claim 12, characterized in that on the sensor block surface at least one sensor cover (12,13) of a sensor chamber (19) is arranged, in which at least one structured portion (16) is introduced, and / or that on the Sensor block surface next to the Sensor covers (12, 13) at least one further cover (14) is arranged, in which at least one structured portion (16) is introduced.

14. Sensor according to one or more of the preceding claims, characterized in that the sensor has a housing (21) with a housing surface, along which the documents of value (5) are transported past the sensor, wherein in the housing surface at least one structured Section (16) is introduced.

15. Sensor according to one or more of the preceding claims, characterized in that the sensor comprises a housing body (2), on whose upper side at least one front element (7, 11) is arranged, along which the value documents (5) transported past the sensor be, wherein in a surface of the front element (7, 11) at least one structured ter section (16) is introduced.

16. Sensor according to one or more of the preceding claims, characterized in that the sensor surface, in particular the front element (7, 11) or the sensor cover (12, 13) or the further cover (14) or the housing surface, at least one recess (8), in or directly below which a measuring head (10, 18) is arranged and / or transmitted by the measuring signals of the sensor and / or in which a window (6) or a transport element, in particular a transport roller (9), is arranged.

17. Sensor according to one or more of the preceding claims, characterized in that the sensor surface, in particular the front element (7, 11) or the sensor cover (12, 13) or the housing surface, at least one translucent, flat portion (26) through be transmitted to the measuring signals of the sensor.

18. Sensor according to one or more of the preceding claims, characterized in that the plurality of elevations (4) or depressions (3) by injection molding or embossing or deep drawing in the Sensoroberflä- surface, in particular in the front element (7, 11) or in the sensor cover (12,13) or in the further cover (14) or in the housing surface, is introduced.

19. Sensor according to one or more of the preceding claims, character- ized in that the sensor surface, in particular the front element (7, 11) or the sensor cover (12, 13) or the further cover (14) or the housing surface, partially or completely consists of one or more of the following materials: plastic, in particular wear-resistant and / or carbon fiber reinforced and / or electrically conductive and / or transparent plastic; Metal or sheet metal, in particular aluminum, magnesium, stainless steel; Glass.

20 sensor component (7, 11, 12, 13, 14, 21) for forming a sensor surface of a sensor (1, 25) according to one or more of the preceding claims, characterized in that the sensor component on its surface at least one structured portion (16), which has a plurality of elevations (4) or a plurality of depressions (3).

21. sensor component according to claim 20, characterized in that the sensor component comprises a housing (21) of the sensor or a sensor cover

(12, 13) for a sensor block (25) or a further cover (14) for a sensor block or a front element (7, 11) of the sensor.

22. Device for checking value documents, in particular banknotes, with at least one sensor according to one or more of claims 1-19.

23. A method for checking value documents, in particular banknotes, in which the value documents (5) are transported past a sensor according to one or more of claims 1-19.

24. The method according to claim 23, characterized in that the value documents (5) by means of belts and / or with the help of rollers (9) along the sensor surface are transported past.

25. The method according to claim 24, characterized in that form during the transport past the value documents (5) along the sensor surface air cushion.