Marking device, method and apparatus for the production thereof and a method for reading a marking device of this type

Abstract

The invention relates to a marking device (21) for the identification of objects, comprising a coding consisting of areas (24, 25) of differing magnetic properties. The marking device is characterised in that it has magnetic areas (24, 25) consisting of a homogeneous, ferromagnetic or ferrimagnetic material, each of said areas having a magnetic anisotropy with an easy and hard magnetic axis, whereby areas with a different orientation of the easy magnetic axis and/or areas with remanence of different strengths succeed each other in at least one specific direction. The invention also relates to a method for producing a marking device of this type and to apparatus for carrying out the method.

Description

[0001] The invention relates to a marking device for the identification of objects, with a coding of regions with different magnetic characteristics, a method and apparatus for making the marking device as well as a method of reading such a marking device.

[0002] For the marking and thus the individual correlation and verification of check cards, credit cards, access cards, electronic keys or the like, a variety of magnetic codings are used, usually mainly in the form of a so-called magnetic strip. For the coding, a permanent magnetic layer is selectively magnetized, i.e. regionally magnetized so that regions of different magnetization result, whereby in the sense of the present description, also nonmagnetized regions, thus regions at which the magnetization are zero are included. With corresponding magnetic field sensors, the magnetic signature or coding can be detected and processing can then be carried out for the corresponding respective purpose.

[0003] There are numerous different proposals for the configuration of the magnetic strips. In U.S. Pat. No. 4,650,978, the naturally random variations of the magnetic characteristic of a magnetic strip, having their origins in variations in coercivity, granularity, layer thickness, surface profile and especially from random variations in the hysteresis loops and the magnetic histories from which they derive, can be used. The methods of U.S. Pat. Nos. 5,616,904 and 4,837,426 for coding are similar. The magnetic structures are digitalized in an appropriate form and used for identification of the objects. A drawback is that the magnetic strips can be manipulated relatively simply and are unstable with respect to external magnetic fields.

[0004] In U.S. Pat. Nos. 5,480,685 and 5,972,438, magnetic strips are described in which magnetic particles are incorporated in a binder matrix, whereby the magnetic strips have respectively two layers of different coercivities. The magnetic strips of U.S. Pat. No. 5,177,344 also have magnetic particles within a binder matrix whereby the magnetic particles are so influenced by the application of an external magnetic failed so that they have magnetic regions of different characteristics. This kind of magnetic strips have the drawback that the magnetic structures can be subsequently altered in that the binder can be heated and the magnetic particles newly oriented by external magnetic fields.

[0005] With the magnetic strips of U.S. Pat. No. 5,365,586, a multiplicity of microcrystalline structures are arranged in a random pattern. The magnetic strips are then subjected to a saturation magnetization, whereby the remnant noise is read out and used for identification.

[0006] In U.S. Pat. No. 5,254,843, the random variations in the time sequence of the flux changes in conventional magnetic bands and strips are used are drawn upon for identification of the respective objects. Here as well, the random structure can easily be reproduced upon recognition. Aside from this, the method requires a randomness of the variations with time which is not always produced for certain in machine writing.

[0007] In the PCT/EP99/08433 which has not been prepublished, a marking device is proposed in which the coding has a magnetic base layer and a magnetic coding layer which cooperate so that over the extent of the base layer and coding layer, there are regions with nonparallel or antiparallel magnetic coupling. Use is here made of the effect of magnetic intermediate layer coupling. The marking device has the advantage of a highly characteristic property which deviates from the usual magnetic marking upon the application of external magnetic fields which is especially that, while the saturation magnetic field blanks out the nonparallel or antiparallel coupling, the original magnetization is restored, however, after removal of the external magnetic field. The coding can thus not be extinguished by external magnetic fields. In addition, use can be made of the effect that magnetic coding which has weakened, for example, because of long storage times or so-called lost magnetic codings, can be reactivated by application of a saturation magnetic field.

[0008] The invention has as its object the provision of a marking device of the type described at the outset which has a durable coding which is difficult to manipulate and is insensitive to external effects. It should also enable a verification without data connection to an external computer. A further object is to provide a method and apparatus for producing such a marking device.

[0009] The first part of the above mentioned object is achieved according to the invention in that magnetic regions are provided of a homogeneous ferromagnetic or ferrimagnetic material that has respectively magnetic anisotropy with magnetically soft and magnetically hard axes [easier and harder axes], whereby in at least one predetermined direction--this is then the intended readout direction--regions with different directions of the easy magnetization axes and/or regions with remanences of different magnitudes follow one another. The basic concept is thus a provision of a spatial distribution of the magnetic anistropy with respective magnetically soft and hard axes. Such an anisotropy can also be designated as bidirectional anisotropy. It is insensitive to external influences to the extent that the ferromagnetic or ferrimagnetic material has a Curie temperature which is significantly above room temperature, preferably above 150.degree. C. as is the case with the ferromagnetic materials Co or NiFe. Thus when reference is made to homogeneous materials, it should be understood that these include elemental substances as well as alloys or chemical compounds of such substances like oxides, to the extent that they, over the extent of the coding disregarding possible crystallinity--remain uniform and do not form a matrix system or the like.

[0010] Advantageously, the marking device is such that the magnetic regions directly bound one another in the predetermined direction. This does not exclude an arrangement in which the magnetic regions are also spaced from one another in the preferred direction whereby the regions between the magnetic regions can be formed as nonmagnetizeable.

[0011] With the invention it is advantageous when the magnetic regions have saturation magnetization which are of equal magnitude.

[0012] By applying to the coding an external magnetic field up to the saturation range, there is a homogeneous magnetization over the extent of the coding which forms a reference and enables a verification test. It will be selfunderstood that this is not a compulsory requirement since the saturation magnetization can also vary over the extent of the coding. When this variation is stored, it can be determined by the verification test, whether a manipulation has occurred or not. The coding as such is stored in terms of the distribution of the magnetic bias or an anisotropy. The marking device of the invention can be produced by applying a coding layer of a homogeneous or ferromagnetic or ferrimagnetic carrier and then generating regions of magnetic anisotropy with magnetically harder or softer axes which in at least one direction have regions with different directions of the soft axis and/or regions with remanences of different magnitudes following one another. This can be accomplished with the magnetic regions directly bounding one another in succession in the preferred direction and/or by having them spaced apart.

[0013] Since the coding layer is of relatively thin configuration, it has been found to be desirable to make use of vapor deposition technology for building up the layer structure, i.e. thermal vapor deposition, sputtering or the like. The coding layer can be provided with a protective layer, for example, of DLC (Diamond Like Carbon) or SiC, which preferably also is applied by vapor deposition.

[0014] The impression of the magnetic anisotropy can be effected in a simple manner in that the coding layer can be subjected to a nonhomogeneous magnetic field during the build up of the layer. The distribution of the nonhomogeneity of this magnetic field enables a pattern of different magnetic anisotropies to be provided and the coding layer to be deposited with a uniform layer thickness.

[0015] The magnetic field, for example, can be generated by nonhomogeneously magnetizing a magnetizable carrier or a magnetizable underlay for the carrier. In the latter case, the carrier is placed on the underlay and the coding layer is built up on the combination of the underlay and carrier.

[0016] The marking device can be especially economically fabricated when a carrier foil is drawn from a supply and brought together with a continuously displaced magnetic foil and both are fed through a coating station in which the coding layer is applied. Then the carrier foil and the magnetic foil should be again separated. It is advantageous to draw the magnetic foil also from a supply and then magnetize it and downstream of the coating station to take it up again in a store. It is especially advantageous if the magnetic foil is passed in an endless path through the coating station. In order to produce such a varying nonhomogeneity of the magnetic field, the magnetic foils should be individually magnetized upstream of the coating station and downstream of the coating station should be again demagnetized or have their demagnetization homogenized. Instead of a magnetic foil, the magnetic field can also be created by means of generating coils.

[0017] An apparatus for carrying out the aforedescribed method is characterized by

[0018] a) a supply store for a carrier foil;

[0019] b) a coating station for forming the coding layer;

[0020] c) a magnetic field unit juxtaposed at least with the coating station for producing a nonhomogeneous magnetic field over the area of the carrier foil;

[0021] d) a receiving store for the take up of the marking device;

[0022] e) guide elements and a drive for feeding the carrier foil from the supply store through the coating station to the receiving store.

[0023] With this apparatus, it can be provided that the magnetic field unit will be arranged upstream of the coating station and that the magnetizable carrier foil is passed through it. Instead, the magnetic field unit can have a magnetic foil which is magnetized nonhomogeneously, whereby the guide elements effect a joining of the carrier foil and the magnetic foil upstream of the coating station. In a concrete manner this can be achieved by providing a supply store for the magnetic foil upstream of the coating station and a receiving store downstream of the coating station and a magnetic field unit which has a magnetizing device which is arranged between the supply store and the coating station.

[0024] As an alternative thereto, however, the magnetic foil can also have an endless configuration and be fed via the guide elements through the carrier foil through the coating station. Advantageously, the magnetic field unit should then include a magnetizing unit in the travel direction of the carrier foil which is upstream of the coating station and which produces a nonhomogeneous magnetic field, while a quenching device for demagnetization or homogenization of the magnetic field is provided between the coating station and the magnetizing unit. The magnetic foil can, for example, be stretched across a support roll which is juxtaposed with the coating station and over which the carrier foil travels. Instead, however, the roll periphery itself can be configured to be magnetizable and here as well a magnetizing unit can be provided for magnetizing the roll periphery and a quenching unit can be provided for demagnetizing or homogenizing the magnetic field. The roll periphery can be provided with a magnetizable coating. In all cases, the quenching device and the magnetizing device should be provided in the direction of rotation of the support roll one after the other in a region of the roll periphery which is free from the carrier foil.

[0025] Alternatively, it can be provided that the magnetic field unit have a multiplicity of magnetic field generating coils. These coils can be arranged in the vicinity of the surface of a carrier roll over the roll periphery of which the carrier foil is guided through the coating station so that during the vapor deposition, a nonhomogeneous magnetic field prevails. According to a further feature of the invention, at least the coating station is provided with a heating unit for producing a homogeneous field preferably above the Curie temperature.

[0026] It is also proposed to provide a further coating station to apply a protective layer on the coding layer. In this case, it is desirable for the coating stations to have vapor deposition units for application of the coding layer by means of thermal vapor deposition or sputtering. The supply store or receiving store can advantageously be formed as a supply roll or as a storage roll.

[0027] The method according to the invention can also be so configured that the magnetic region has a vapor deposition device which is inclined to the surface of the carrier whereby with reference to the plane of the carrier at least two different vapor deposition directions are provided. In this manner alone, the anisotropic distribution according to the invention can be achieved with different directions of the easy magnetization access. This effect can, however, also be amplified by the simultaneous impression of a preferably nonhomogeneous magnetic field which is respectively codirectional with the vapor deposition device.

[0028] More concretely stated, the aforedescribed method can be so carried out that for the vapor deposition in a first vapor deposition direction region, the carrier is covered with a first mask and that in the vapor deposition in a second vapor deposition direction at least the regions of the carrier which the first vapor device formed a deposit upon are covered with a second mask. Then the first and second vapor deposition units can also be identical when they include units with the aid of which the vapor deposition direction can be altered. It is possible that in the vapor deposition in the second vapor deposition direction with the second mask, regions which had not been covered previously be vapor deposition could be covered and at least a portion of these regions, after removal of the second mask and the application of a third mask, can be vapor deposited in a third vapor deposition direction.

[0029] In order to be able to make the marking device in a continuous process, the invention provides that a carrier foil and at least two masking foils are drawn from respective supplies and before each vapor deposition, the carrier foil and one of the masking foils are brought together and the vapor deposition carried out from the side of the masking foil and the masking foil again be separated from the carrier before the carrier foil is combined with a further masking foil. The masking foil can be provided with a certain mask pattern already before its withdrawal from the supply. Alternatively thereto it is proposed that the masking foil once withdrawn from the supply but before being brought together with the carrier foil, be provided with cutouts. An apparatus for carrying out the method is characterized by

[0030] a) a supply store for a carrier foil;

[0031] b) a plurality of coating stations for vapor depositing on the carrier foil in different vapor deposition directions;

[0032] c) a number of supply stores for a masking foil corresponding in number to the number of coating stations;

[0033] d) receiving stores for taking up the masking foils;

[0034] e) a receiving store for taking up the marking device;

[0035] f) guide elements and a drive for feeding the carrier foil from the supply store through the coating stations to a receiving store and for feeding each of the masking foils together with the carrier foil upstream of a coating station and for separating the carrier foil and the masking foil downstream of a coating station.

[0036] Advantageously, each coating station has a supply store for a masking foil and a receiving store for the take up of the masking foil. Between each supply store for the masking foil and the junction for the masking foil and the carrier foil, respective mask forming stations can be provided to produce cutouts in the masking foil and thus impress upon each masking foil an individual mask pattern. The mask forming stations can, for example, have a laser burning device which has a control unit for varying the position of the laser burning device.

[0037] Also with this apparatus, a further coating station can be provided for applying a protective layer to the coding layer. The supply store can advantageously be a supply roll and the receiving store a storage roll. Advantageously, the coating station has carrier rolls over whose roll periphery the carrier foil and the masking foil are guided.

[0038] The method of the invention can also be carried out in such manner that initially a layer is applied and this layer during or after application is so magnetized that it has a homogeneous anisotropic direction so that the layer is then:

[0039] a) subjected to a homogeneous magnetic field and a nonhomogeneous temperature field, or

[0040] b) subjected to a nonhomogeneous magnetic field and a homogeneous temperature field, or

[0041] c) subjected to a nonhomogeneous magnetic field and temperature field, whereby the temperature lies above the Curie temperature of the layer.

[0042] By heating the homogeneously magnetized layer to a temperature above the Curie temperature of the layer. By heating the homogeneously magnetized layer to a temperature above the Curie temperature the distributions of the different magnetic anistropies can be so controlled that either the temperature field under simultaneous effect of a magnetic field is nonhomogeneously formed whereby the magnetic field can either be homogeneous or nonhomogeneously formed or with a homogeneous temperature field, a nonhomogeneous magnetic field is produced.

[0043] To create the magnetic field both in the formation of the layer and also in the subsequent temperature treatment, a magnetizable carrier can be provided which is correspondingly magnetized. Instead, a magnetizable underlay can also be provided which is correspondingly homogeneously or nonhomogeneously magnetized and the carrier with the layer can be placed on this underlay. To the extent that a magnetic field is impressed subsequent to the layer formation, the combination of underlay and carrier can be exposed to the temperature field. To the extent that the method is carried out continuously, a carrier foil should be drawn from a supply and brought together with a continuously displaced magnetic foil and the two fed through a heating station after which they are again separated. The magnetic foil can also be initially drawn from a supply and then magnetized and then downstream of the heating station taken up in a store. Alternatively, the magnetic foil can be displaced in a closed path through the heating station, whereby the magnetic foil is magnetized upstream of the heating station and downstream of the heating station is demagnetized or magnetization homogenized. The latter is especially advantageous when the carrier foil is to be exposed to a nonhomogeneous magnetic field. An apparatus for carrying out your method is characterized in accordance with the invention by

[0044] a) a supply store for a carrier foil;

[0045] b) a treatment station with a magnetization unit and a heating unit;

[0046] c) a receiving store for taking up the marking device;

[0047] d) guide elements and a drive for feeding the carrier foil from the supply store through the treatment station to the receiving store.

[0048] With the aid of this apparatus a corresponding method can be carried out in which in the treatment station a nonhomogeneous or homogeneous magnetization and or homogeneous or nonhomogeneous heat treatment can be effected. A prerequisite for the application of a homogeneous ferromagnetic or ferrimagnetic layer with a homogeneous orientation of the bidirectional anisotropy on the carrier foil. Advantageously this can be achieved with an apparatus in which the aforedescribed apparatus is completed with the following apparatus parts:

[0049] a) a coating station for applying a layer with homogeneous anistropy to the carrier foil;

[0050] b) guide elements and a drive for feeding the carrier foil from the supply store through the coating station and the treating station to the receiving store.

[0051] The coating station is provided with a device for producing a sufficiently strong homogeneous magnetic field that fixes the magnetic anisotropy. The device can be so configured that directly above the carrier foil and between the coating station and the carrier foil at a location at which the material meets the carrier foil a sufficient magnetic field is created for a new orientation of the magnetic anisotropy.

[0052] The application of a magnetic field can be effected in this case also with the aid of a magnetic foil which is correspondingly homogeneous or nonhomogeneous magnetized, whereby the guide elements effect a joining of the carrier foil and the magnetic foil upstream of the treatment station. In more concrete terms, this can be achieved in that a supply store is provided for the magnetic foil upstream of the treatment station and a receiving store is provided downstream of the treatment station and the magnetizing unit is located between the supply store and the heating device.

[0053] Instead, the magnetic foil can also be of endless configuration and can be fed via the guide elements together with the carrier foil through the heating unit. To the extent that a nonhomogeneous magnetic foil is to be produced, the magnetizing unit can be arranged in the travel direction of the carrier foil upstream of the heating unit and, in addition, a quenching device can be provided for demagnetization or homogenizing the magnetic field between the heating unit and the magnetizing unit. The magnetic foil can be fed freely over rerouting rollers it can, however, also be stretched over a support roll which is juxtaposed with the treatment station. In this case, however, an additional magnetic foil can be eliminated when the roll periphery is magnetizable or has a magnetizable coating. The quenching device and the magnetization device are preferably located one after the other in the direction of rotation of the support roll in the region of the support roll which is free from the carrier foil. Depending upon the type of method, the treatment station can have heating units for locally heating the carrier foil whereby lasers are especially suitable for this purpose. In this case, a homogeneous magnetic field is sufficient as generated by a corresponding magnetizing unit. Alternatively, the treatment station can have a heating device for producing a homogeneous temperature field as well as a magnetic field for producing a nonhomogeneous magnetic field. The alteration of a homogeneously magnetized layer in the sense of the present invention can be effected not only by a subsequent impression with a magnetic field and a temperature field, but local ion bombardment in the sense that the alteration of the direction of the anistropy and/or the remanence will occur. The ion bombardment can be effected with the aid of a focused ion beam. Alternatively, the ion bombardment can be effected on an areawide basis and in the region of the carrier, a nonhomogeneous electronic charge field can be generated.

[0054] This can be so arranged that an electrically chargeable carrier is charged prior to the ion bombardment with a nonhomogeneous electric charge. The electric charge can, for example, be produced with the aid of a nonhomogeneously electrically charged underlay on which the carrier is placed.

[0055] The carrier foil is advantageously drawn from a supply and after the coating brought together with a continuously displaced charging foil as an underlay. Both are then subjected to areawide ion bombardment. Then they are again separated from one another. The charging foil can also be drawn from a supply and then charged and after the ion bombardment can be taken up in a store.

[0056] In a variation, the charging foil can be also circulated as an underlay through the ion bombardment station and the charging foil can be charged upstream of the ion bombardment station and downstream of the ion bombardment station again discharged or can have its electronic charge homogenized. In this manner individual charge patterns can be applied.

[0057] Alternatively thereto it is proposed that a charging foil and a masking foil be continuously drawn from respective supplies and brought together and that the ion bombardment then be effected from the side of the masking foil and the masking foil again separated from the carrier foil. In this case, the masking foil, after withdrawal from the supply and prior to being brought together with the carrier foil, should be provided with cutouts. It can also be provided that the masking foil be held in a supply already provided with cutouts.

[0058] The apparatus can be formed analogously to the apparatus in which a treatment station is provided with a magnetization unit and a heating unit. Instead of this treatment station, now an ion

[0059] The apparatus can be formed analogously to the apparatus in which a treatment station is provided with a magnetization unit and a heating unit. Instead of this treatment station, now an ion bombardment station is provided for the ion beam treatment of the layer on the carrier foil. With the aid of the ion bomb station, a focused ion beam can be generated whereby a controlled device cooperates therewith is a targeted control of the ion beam. A nonhomogeneous ion beam treatment can, however, be produced with an areawide ion beam when it impinges on regions of the carrier foil with a nonhomogeneous charge field which has a charge corresponding to the charge of the ions and thus can repel the ion beam in these regions so that the ions of the beam do not impinge upon the carrier foil.

[0060] Finally, it can, for example also be effective to guide an electrically chargeable carrier foil through the ion bombardment station, where a charge device applies a nonhomogeneous electric charge thereto. Alternatively, an electrically chargeable charging foil can be passed through the ion bombardment station and can have been provided with a nonhomogeneous electric charge, the guide elements effecting a meeting of the carrying foil and the charging foil upstream of the ion bombardment station. A supply store can be provided for the carrier foil upstream of the ion bombardment station and a receiving store downstream of the ion bombardment station while a charging device for applying a nonhomogeneous charge to the charging foil is arranged between the supply station. Instead, the carrier foil can, however, be configured as an endless charging foil and guided via the guide elements together with the carrier foil through the ion bombardment station. In this case, the charging device is provided in the travel direction of the carrier foil upstream of the ion bombardment station and a quenching device can be provided for discharging or homogenizing the electric charge bottom the ion bombardment and the charging device. The charging foil can also be stretched over a support roll which is juxtaposed with the ion bombardment station.

[0061] In the latter case, a charging foil can be eliminated when the roll periphery of the support roll is chargeable with an electric charge. Then a charging device for charging the roll periphery and a quenched device for discharging or homogenizing the electric charge of the roll periphery should be provided.

[0062] To enable the roll periphery to be chargeable, it can also be provided with a corresponding coating.

[0063] The charging device and the discharging device are advantageous disposed one after the other in the direction of rotation of the support roll and in a region of the support roll which is free from the carrier foil.

[0064] As an alternative thereto, it can be provided that a masking foil is fed through the ion bombardment station and that the guide elements effect a meeting of the carrier foil and the masking foil upstream of the ion bombardment station in such manner that the ion bombardment is carried out from the side of the masking foil and that the guide elements separate the carrier foil and masking foil downstream of the ion bombardment station. In this case as well, the ion bombardment can be effected on an area wide basis, whereby the impact on the layer on the carrier foil is limited by the cutouts in the masking foil.

[0065] In the apparatus, an already preformed masking foil can be introduced. As an alternative thereto, it is proposed in accordance with the invention that between a supply store for the masking foil and the meeting of the masking foil and the carrier, a mask forming station be arranged to produce the cutouts in the masking foil, whereby the masking forming station is provided as a laser burning unit with a control device for varying the position control of the laser burning unit.

[0066] The subject of the invention is also a method of reading the above described marking devices with the aid of at least one magnetic field sensor.

[0067] According to the invention, the coding is subjected to at least two reading processes whereby one reading process is effected in a zero field and one reading processing an externally applied magnetic field or the reading processes are effected under different magnetic fields. In the first mentioned reading process, information stored in the magnetic regions is detected based upon location, for example, by reading certain features of the hysteresis loops. In the second reading process, which preferably is carried out under saturation magnetization, the distribution of the saturation magnetization is detected and compared with a predetermined reference structure. The sequence of the two reading processes does not matter.

[0068] It is also of advantage that for the reading of the marking devices according to the invention, conventional magnetic field sensors are suitable, that is, for example, inductive sensors, magnetoresistive sensors, magneto-optical sensors, Hall-effect sensors or SQUID sensors.

[0069] The reading which is resolved as to location is effected by relative movement between the magnetic field sensor and the marking device and it is not significant whether one or the other of the two is moved. A plurality of magnetic sensors can also be used to detect the magnetic structure of the marking device in a stationary state but as a function of position.

[0070] To detect the information stored in the coating, various features of the hysteresis loop can be considered. It is simple to detect the remanence in a zero field or a very small magnetic field. Instead, it is, however, also possible to detect the flux change at the boundaries between two positions since with the marking device according to the invention at these boundaries stray fields arise whose distribution in a certain direction from the coding.

[0071] The invention is described in greater detail with reference to the drawing based upon examples. The drawing shows:

[0072] FIG. 1 a plan view on a portion of a marking device in remanence, illustrating the hysteresis loops of two magnetic regions;

[0073] FIG. 2 a longitudinal section through the marking device according to FIG. 1;

[0074] FIG. 3 a diagram illustrating the principles of the marking device according to FIGS. 1 and 2 with a magnetic field sensor;

[0075] FIG. 4 an illustration of the principles for producing a nonhomogeneous magnetic field by means of a magnetizable underlay;

[0076] FIG. 5 an apparatus for producing a marking device by means of layer build up in a nonhomogeneous field;

[0077] FIG. 6 an apparatus for producing a marking device by means of inclined vapor deposition in two deposition directions;

[0078] FIG. 7 a device for producing a marking foil by means of ion bombardment.

[0079] In FIGS. 1 and 2, a marking device 21 has been shown in which a homogeneous ferromagnetic layer 23 is applied to a carrier 22. The ferromagnetic layer 23, for example, of FE, CO, NI, a magnetic rare earth metal, an alloy or a ferrite itself has a randomly arranged array of magnetic regions distributed over its area and, for example, indicated at 24 or 25. In the production of the ferromagnetic layer 23 by corresponding local field application a magnetic anisotropy is so generated that in the magnetic regions 24, 25 the easy access is oriented corresponding to the arrows (in FIG. 2 symbolized by the point in the circle).

[0080] If a measurement is carried out by means of a magnetic field sensor in the direction indicated by the arrow below the carrier 22 (FIG. 2), i.e. the reading direction, the magnetic regions 24 have a magnetic characteristic corresponding to the hysteresis loop 26 while the magnetic regions 25 have a magnetic property corresponding to the hysteresis loops 27. At the transitions between two enabling regions 24 and 25, there is a difference in the strengths of the remanent magnetizations with respect to a reading direction. The flux change there produces stray fields which, like the local magnetization itself has a structure affecting the signal pattern which corresponds to the coding.

[0081] By imposing an external magnetic field in the saturation range, in the directions of the magnetic field H a uniform magnetization arises. Upon removal of the magnetic field, the illustrated structure returns.

[0082] In FIG. 3, the marking device 21 has been turned so that the carrier 22 is disposed at the upper side and the ferromagnetic layer 23 on the lower side. Below it, a magnetic field sensor 31 is arranged which has a reading head 32 over which the marking device 21 with the carrier 22 is displaced past in the pull through direction. At the boundaries of the different magnetized regions in the zero field, a stray field is generated which induces a current pulse 33. Via an external current source 34 an additional current can be fed to a coil 35 at the reading head 32 whereby at the location of the detection an external magnetic field is detected. By the readout, a signal develops which is processes in an amplification stage 37 and in a further stage 38. If the external current is equal to zero then the stored information can be read. If the current is sufficient to saturate the ferromagnetic layer 23, the current pulse 33 disappears. In this manner a verification test of the coding is possible.

[0083] It is especially advantageous for the magnetic field sensor 31 and the ferromagnetic layer 23 to match each other in shape so that the saturation field corresponds to a field stretch in which the characteristic lines of the magnetic field sensor 31 are linear to enable a distinction between saturation of the coding and saturation of the magnetic field sensor. A further possibility is overcoming the saturation problem of several magnetic field sensors, for example, inductive or magneto-resistive magnetic field sensors is for the saturation field to be applied in a direction which does correspond to the sensitive region of the magnetic field sensor. It is also advantageous to use a magnetic field sensor which is suitable for detection of the local magnetization of the layer, for example (a magneto-optical detection device) to exclude influence on the external field on the sensitivity of the magnetic field sensor.

[0084] FIG. 4 shows a carrier plate 41 on which a magnetic foil 42 is placed. The magnetic foil 42 is magnetized perpendicularly to the layer plane in strips--for example indicated at 43--and indeed in a strip 43 with a preferred direction downwardly and an adjacent strip 43 with a preferred direction upwardly as symbolized by the arrows. This yields a stray field configuration as shown schematically by the semicircles 44. The so-configured stray field is sufficient to localize the direction of the magnetic anisotropy.

[0085] On the magnetic foil 42 a carrier foil 45 is placed and in which, by means of the magnetic foil 42, a magnetic field distribution is produced whose components in the layer plane vary in accordance with the pattern therebelow which has been indicated by the horizontal arrows on the carrier foil 45. By the vapor deposition of a suitable ferromagnetic material or ferrimagnetic material on the carrier foil 45, the magnetic field distribution determines the spatial distribution of the magnetic anisotropy and thus the signature of the coding.

[0086] FIG. 5 shows an apparatus 46 in which the principle of FIG. 4 is used in a continuous manufacturing process. The apparatus 46 is disposed in a housing not either shown in detail and which is under high vacuum.

[0087] The apparatus 46 has two vapor deposition stations 47 and 48, whereby each vapor deposition station 47, 48 has a support roll 49, 50 associated therewith and which are flanked by respective rerouting rollers 51, 52 or 53, 54 in their lower regions.

[0088] The first vapor deposition station 47 is provided above the respective support roll 49 with a vapor deposition device 55. The support roll 49 is provided with a magnetic layer along its roll periphery, for example, a thin polymer layer of about 3 mm, in which a high proportion of ferromagnetic particles are embedded. Below the support roll 49 and between the associated rerouting rolls 51, 52, at the left side a magnetizing unit 59 is provided which can have a row of permanent magnets and/or magnetic field generating coils and which is capable of providing the magnetic layer 58 with a certain magnetization pattern which in its simplest form can have the form shown in FIG. 4. The magnetic layer 58 produces a nonhomogeneous magnetic field corresponding to its magnetization. To the right adjacent the magnetizing unit 59, a quenching unit 60 is arranged which either completely demagnetizes the magnetic layer 58 or magnetizes it homogeneously and thus eliminates the nonhomogeneous magnetization impressed by the magnetizing unit 59. On a supply roll 61, a carrier foil 62, for example, a polyester foil, is rolled up. In operation, the carrier foil 62, by the drive of the support rolls 49, 50, is withdrawn from the supply roll 61 and pass around the first rerouting roller 51 and onto the magnetic layer 58 where it is entrained by the rotation of the support roll 59 therewith. In the vapor deposition unit 55, the carrier foil 62 is provided with a layer 63 of ferromagnetic material. Through the spatial magnetic field distribution, created by the magnetic layer 58, the desired directional distribution of the magnetic anisotropy is produced.

[0089] After passing around the rerouting rollers 52, 53, the carrier foil 62 passes through the second vapor deposition station 48 where it travels onto the periphery of the respective support roll 50 and travels with the support roll 50. It thus passes the vapor deposition device 64 which applies a protective layer 65 over the entire area, for example, of DLC. After traversing the second vapor deposition station 28, the carrier foil passes around the last rerouting roller 54 and is taken up by a storage roll 66. It can then be subsequently subdivided into individual sheets.

[0090] With the apparatus 71 according to FIG. 6, another manufacturing process is used. The apparatus 71 has three vapor deposition stations 72, 73, 74, whereby the vapor deposition stations 72, 73, 74 have support rolls 75, 76, 77 associated with them and which, in their lower regions, are flanked by rerouting rollers 78, 79 or 80, 81 or 82, 83. Above the support rolls 75, 76, 77, respective vapor deposition devices 84, 85, 86 are arranged.

[0091] Upstream of the first support roll 75 there is located a supply roll 88 on which a carrier foil 89 is rolled. Above the supply roll 88, a further supply roll 90 is provided on which a making foil 91 is provided.

[0092] The further supply roll 90 is juxtaposed with a roll 92 with the aid of which opens, for example, indicated at 93 can be burned into the masking foil 91.

[0093] Upstream of the second support roll 76 there is found a third supply roll 94 on which a second masking foil 95 is rolled. The third supply roll 94 is also here juxtaposed with a laser device 96 with openings, for example, designated with 97 are burned out of the masking foil 95.

[0094] In operation, the carrier foil 89 and the masking foils 91, 95 are drawn at the same speed from their supply rolls 88 or 90 or 94, for example by the drive of the support rolls 75, 76, 77. In the masking foils 91, 95 shortly downstream of their respective supply rolls 90 or 94, a pattern of cutouts 93, 99 is burned with the aid of the laser devices 92, 96. By corresponding control of the laser beams generated by the laser devices 92, 96, more can also be provided--, predetermined patterns or continuously changing random patterns, for example, made with the aid of a random generator, can be produced, which are in a complimentary relationship as further detailed below.

[0095] The carrier foil 89 and the masking foil 91 travel onto the first rerouting roller 78 together and are entrained by the support roll 75.

[0096] The masking foil 91 lies outside of the carrier foil 89. Both are based together in the upper region of the support roll 75 past the first vapor deposition device 84 whereby the vapor deposition device vapor deposits a ferromagnetic layer 98 in a first direction with the deposit however appearing only in the regions of the cutouts 93 on the carrier foil 89. After passing around the rerouting roller 79, the masking foil 91 is led upwardly away from the carrier foil 89 and rolled up on a storage roll 99.

[0097] The carrier foil 89 then travels horizontally to the next rerouting roller 80 and combines their with the second masking foil 95. Both then travel on the support roll 76. With the aid of the vapor deposition unit 85, a second ferromagnetic layer 100 is vapor deposited on the carrier foil 89 with a second direction different from the first. This deposition on the carrier foil 89 is also delimited to the regions of the cutouts 97. The cutouts 97 are so arranged that they leave on the carrier foil 89 only regions free which are covered in the first coating station by the masking foil 91 there. Because of the different vapor deposition directions of the vapor deposition devices 84 and 85, regions are produced with different directions of the easy axis of magnetic anistropy.

[0098] Next, the thus coated carrier foil 89 loops around the rerouting rollers 81, 82 and passes into the last support roll 77. With the aid of the further deposition unit 86, a protective layer 103 is applies to the ferromagnetic coding layer 102. After passing the last rerouting roller 83 the carrier provider 89 with the coating is rolled up on a storage roll 103. It can then be correspondingly packaged depending upon its respective use.

[0099] FIG. 7 shows a further apparatus 111 for the production of a marking device with regional anisotropy. It has, in the sequence of travel, a first vapor deposition station 112, an ion bombardment 113 and a second vapor deposition station 114. The stations 112, 113, 114 are associated with support rolls 115, 116, 117 which are flanked in their lower regions respectively by two rerouting 118, 119 or 120, 121 or 122, 123.

[0100] The vapor deposition stations 112, 114 are each provided with a vapor deposition device 124, 125 above the associated support roll 115, 117. In the ion bombardment station 113, above the associated support roll 116 an ion bombardment device 117 is arranged. Below the support roll 116 and between the rerouting rollers 120, 121 associated therewith is a charging distribution device 128 deposited at the left side and with which the support roll 116 is provided with regions with positive charge and/or regions of negative charge. This can be effected, for example, in accordance with the principles of the laser printer. For this purpose, the support roll 116 is provided with an electrically chargeable coating 129. To the right of the charge distributing device 128, a quenching device 130 is arranged which either completely discharges the surface of the support roll 116 or provides it with a homogeneous electric charge.

[0101] On a supply roll 131, a carrier foil 132 is rolled. In operation, the carrier foil 132, for example by driving the support rolls 115, 116, 117, is drawn from the supply roll 131, passes around the first rerouting roller 118 and passes onto the periphery of the first support roll 115 with which it is entrained. The carrier foil is thereby displaced past the first vapor deposition device 124 and is provided, by sputtering under a homogeneous magnetized field, with a ferromagnetic layer 133. With this layer 133, the carrier foil travels around the next following rerouting rollers 119, 120 and onto the periphery of the second support roll 116 and loops about the latter. Thus the carrier foil travels past the ion bombardment device 127 which fires onto the layer 133 over the entire width of the carrier foil 132. Because of the charge distribution on the surface of the support roll 116, which was produced previously by the charge drawbacks device 128, there are formed on the surface of the first layer 133, regions which are repellant for the ions of the ion bombardment device 127 and regions with attractive potential. In the regions with attractive potential, the layer 133 is so influenced that the magnetic anisotropy is altered in its direction so that a coding layer 134 results.

[0102] The support roll 116, on each pass has its charge homogenized by the quenching device 130, that is either completely discharged or provided with a homogeneous charge, at each pass upstream of the charge distribution device 128 so that the charge distribution device 128 always produces a new randomly generated distribution charge pattern on the support roll 116.

[0103] After looping around the rerouting rollers 121, 122, the carrier foil 132 travels into the second vapor deposition station 114 where its here guided again over the periphery of a support roll 117. There the layer 133 receives, with the aid of the vapor deposition device 125 and over its entire area, a protective layer 135.

[0104] The carrier foil 132 then travels around the last rerouting roller 123 and is rolled up in a storage roll 136. It can be subsequently subdivided.

[0105] It will be understood that in FIGS. 6 and 7 as well devices 71, 111 can be disposed within a housing which is under high vacuum.

Claims

1. A marking device 21 for the identification of objects, with a coding of regions (24, 25) with different magnetic properties, characterized in that magnetic regions (24, 25) of a homogeneous ferromagnetic material or ferrimagnetic material are provided which each have a magnetic anisotropy with magnetic easy and hard axes, whereby in at least a certain direction, regions with different orientations of the easy axis and/or regions with remanences of different amplitude follow one another.

2. A marking device according to claim 1, characterized in that magnetic regions (24, 25) in the determined direction are directly adjacent one another.

3. A marking device according to claims 1 or 2, characterized in that magnetic regions (24, 25) in the determined direction are spaced apart.

4. A marking device according to claim 3, characterized in that magnetic regions between the magnetic regions are magnetizable.

5. A marking device according to one of claims 1 to 4, characterized in that magnetic regions have saturation magnetizations of equal magnitudes.

6. A method of producing a marking device according to one of claims 1 to 5, characterized in that a coding layer (23) of a homogeneous ferromagnetic material or ferrimagnetic material is applied to a carrier (22) and that regions (24, 25) with magnetic anistropy with magnetically easier and harder axes are so produced that at least in a certain direction regions with different orientations of the easier axis and/or regions with reminances of the different amplitudes follow one another.

7. The method according to claim 6, characterized in that the coding layer (23) is so constructed that magnetic regions (24.25) directly border one another in the certain direction.

8. The method according to one of claims 6 or 7, characterized in that the coding layer is so constructed that the magnetic regions are spaced apart in the certain direction.

9. The method according to claim 8, characterized in that the coding layer is so constructed that the regions between the magnetic regions are not magnetizable.

10. The method according to one of claims 6 to 9, characterized in that the coding layer (23) is so constructed that the magnetic regions (24, 25) have saturation magnetizations of equal magnitudes.

11. The method according to one of claims 6 to 10, characterized in that the coding layer (23) is produced by vapor deposition.

12. The method according to one of claims 6 to 11, characterized in that a protective layer (65, 101, 135) is applied to the coding layer (63, 64, 100, 134), especially by vapor deposition.

13. The method according to one of claims 6 to 12, characterized in that the coding layer (63) upon layer build up is impressed with a nonhomogeneous magnetic field.

14. The method according to claim 13, characterized in that to produce the magnetic field a magnetizable carrier is nonhomogeneously magnetized.

15. The method according to claim 13, characterized in that to form the magnetic field a magnetizable underlay (58) is nonhomogeneously magnetized and that the carrier (62) is placed on this underlay (58) and the build up of the coding layer (63) is effected on the combination of the underlay (58) and the carrier (62).

16. The method according to claim 15, characterized in that a carrier foil is drawn from a supply and brought together with a continuously displaced magnetic foil and both are fed through a coating station in which the coding layer is applied.

17. The method according to claim 16, characterized in that the carrier foil and magnetic foil are separated downstream of the coating station.

18. The method according to claim 16 or 17, characterized in that the magnetic foil is drawn from a supply and the magnetized and that downstream of the coating station is taken up in a store.

19. The method according to claim 16 or 17, characterized in that the magnetic foil (58) is spaced endlessly through the coating station.

20. The method according to claim 19, characterized in that the magnetic foil (58) is magnetized upstream of the coating station (47) and downstream of the coating station (47) is demagnetized or has its magnetization homogenized.

21. The method according to claim 13, characterized in that the magnetic field is produced by magnetic field generating coils.

22. The apparatus for carrying out the method according to one of claims 13 to 21, characterized by a) a supply store (61) for a carrier foil (62); b) a coating station (47) for depositing a coding layer (63); c) a magnetic field unit (59) juxtaposed with at least the coating station (47) for producing a nonhomogeneous magnetic field over the area of the carrier foil (62); d) a receiving store (66) for taking up the marking device; e) guide elements (49 to 54) and a drive for feeding the carrier foil (62) from the supply store (61) through the coating station (47) to the receiving store (66).

23. The apparatus according to claim 22, characterized in that the magnetic field unit is arranged upstream of the coating station and that a magnetizable carrier foil is fed through them.

24. The apparatus according to claim 22, characterized in that the magnetic field arrangement has a magnetic foil which is nonhomogeneous magnetized and that the guide elements effect a meeting of the carrier foil and the magnetic foil upstream of the coating station.

25. The apparatus according to claim 24, characterized in that a supply for the magnetic foil is provided upstream of the coating station and that the magnetic field unit has a magnetization device which is disposed between the supply store and the coating station.

26. The apparatus according to claim 24, characterized in that the magnetic field is formed with an endless configuration and is passed by the guide elements together with the carrier foil through the coating station.

27. The apparatus according to claim 26, characterized in that the magnetic field unit has a magnetizing device located in the travel direction of the carrier foil upstream of the coating station and generates a nonhomogeneous magnetic field, and that a quenching device for demagnetization or homogenizing the magnetic field between the coating station and the magnetizing device.

28. The apparatus according to claim 26 or 27, characterized in that the magnetic foil is stretched over a support roll which is associated with the coating station.

29. The apparatus according to claim 22, characterized in that the coating station (47) is associated with a support roll (49) over the roll periphery (58) of which the carrier foil is passed through the coating station (47) and that the roll periphery (58) is configured to be magnetizable.

30. The apparatus according to claim 29, characterized in that the magnetic field device has a magnetizing unit (59) for magnetizing the roll periphery (58) which generates a nonhomogeneous magnetic field and that a quenching device (60) is provided for demagnetization or homogenizing the magnetic field.

31. The apparatus according to one of claims 28 or 30 characterized in that the roll periphery has a magnetizable coating (58).

32. The apparatus according to one of claims 29 or 31, characterized in that the quenching device (60) and the magnetizing unit (59) are disposed in the direction of rotation of the support roll (57) one after the other in the region of the support roll (47) which is free from the carrier foil (62).

33. The apparatus according to claim 22, characterized in that the magnetic field unit has a plurality of magnetic field generating coils.

34. The apparatus according to claim 33, characterized in that the coils are arranged in the region of the surface of a carrier roll over whose roll periphery the carrier foil is fed through the coating station.

35. The apparatus according to one of claims 22 to 34, characterized in that at least the coating station has a heating device for generating a homogeneous temperature field.

36. The apparatus according to one of claims 22 to 35, characterized in that a further coating station (48) is provided for applying a protective coating (65) to the coding layer.

37. The apparatus according to one of claims 22 to 36, characterized in that the coating stations (47, 48) have at least one vapor deposition unit.

38. The apparatus according to one of claims 22 to 37, characterized in that the supply store or the supply stores and the receiving store or the receiving stores are configured as supply rolls (61) or storage rolls (66).

39. The apparatus according to one of claims 22 to 38, characterized in that the coating stations (47, 48) have at least one carrier roll (49, 50) over whose roll peripheries the carrier foil (62) is fed.

40. The method according to one of claims 6 to 12, characterized in that the regions have layers formed by inclined vapor deposition on the surface of the carrier (89), whereby at least two different vapor deposition directions are used.

41. The method according to claim 40, characterized in that the vapor deposition directions are effected by identically oriented magnetic fields.

42. The method according to one of claims 40 and 41, characterized in that the vapor deposition in a first vapor deposition direction regions of the carrier (89) are covered by a first mask and that during the vapor deposition in a second vapor deposition direction at least the regions of the carrier (89) which were vapor deposited with the first vapor deposition direction are covered with a second mask (95).

43. The method according to claim 42, characterized in that in the vapor deposition in the second vapor deposition direction, regions have not theretofore been vapor deposited are also covered by the second mask and at least a portion of these regions, after removal of the second mask and application of a third mask are vapor deposited in a third vapor deposition direction.

44. The method according to claim 42, characterized in that a carrier foil (89) and at least two masking foils (91) and (95) are drawn from respective supplies (88, 90, 94) and before each vapor deposition, the carrier foil (89) and one of the masking foils (91, 95) are brought together and the vapor deposition is then effected from the side of the masking foil (91, 95) and the masking foil (91) is again separated from the carrier foil (89) before the carrier foil (89) is brought together with a further masking foil together.

45. The method according to claim 44, characterized in that the masking foils (91, 95) are each provided with cutouts (93, 97) after being withdrawn from the supply (90, 94) and before being brought together with the carrier foil (89).

46. The apparatus for carrying out the method according to one of claims 40 to 45, characterized by: a) a supply store 88 for a carrier foil (89); b) a plurality of coating stations (72, 73) for vapor depositing the carrier foil (89) in different vapor deposition directions; c) a number of supply stores (90, 94) have masking foils (90, 95) corresponding in number to the number of coating stations (72, 73); d) receiving stores for taking up the masking foils; e) a receiving store (104) for taking up the marking device; f) guide elements (75 to 83) and a drive for feeding the carrier foil (89) from the supply store (78) through the coating stations (72, 73) to the receiving store (104) and for feeding together the carrier foil (89) with each of the masking foils (91, 95) upstream of a coating station (72, 73) and for separating the carrier foil (89) and the masking foil (91, 95) downstream of a coating station.

47. The apparatus according to claim 46, characterized in that each coating station (72, 73) is associated with a supply store (90, 94) for a masking foil (91, 95) and a receiving store (99, 101) for taking up the masking foil (91, 95).

48. The apparatus according to one of claims 46 or 47, characterized in that between supply stores (90, 94) for the masking foil (91, 95) and the meeting of the masking foils (91, 95) and the carrier foil (89), respective mask forming stations (92, 96) are arranged for producing cutouts (93, 97) in the masking foils (91, 95).

49. The apparatus according to claim 48, characterized in that the mask forming stations (92, 96) has a laser burning unit.

50. The apparatus according to claim 49, characterized in that the mask forming stations (92, 96) each have a control device for varying the position of the laser burning unit.

51. The apparatus according to one of claims 46 to 50, characterized in that a further coating station (74) is provided for providing a protective layer (103) on the coding layer (102).

52. The apparatus according to one of claims 46 to 51, characterized in that the supply stores are configured as supply rolls (88, 90, 94) and the receiving stores as storage rolls (99, 101, 104).

53. The apparatus according to one of claims 46 to 52, characterized in that the coating stations (72, 73, 74) have carrier rolls (75, 76, 77) under whose roll peripheries the carrier foil (89) and the masking foils (91, 95) are guided.

54. The method according to claims 6 to 12, characterized in that at least one homogenized magnetized layer is created and the layer is subjected to: a) a homogeneous magnetic field and a nonhomogeneous temperature field; or b) a nonhomogeneous magnetic field and a homogeneous temperature field; or c) a nonhomogeneous magnetic field and a temperature field, whereby the temperature lies above the Curie temperature of the layer.

55. The method according to claim 54, characterized in that to create the magnetic field, magnetizable carrier is magnetized.

56. The method according to claim 54, characterized in that to create the magnetic field, magnetizable underlay is magnetized and that the carrier with the layer is placed on this underlay and the combination of the underlay and carrier is subjected to the temperature field.

57. The method according to claim 56, characterized in that a carrier foil is withdrawn from a supply and brought together with a continuously displaced magnetic foil as an underlay and both are fed through a heating station.

58. The method according to claim 57, characterized in that a carrier foil and magnetic foil are separated downstream of the heating station.

59. The method according to one of claims 57 and 58, characterized in that the magnetic foil is drawn from a supply and then magnetized and downstream of the heating station is taken up in a store.

60. The method according to one of claims 57 and 58, characterized in that the magnetic foil is shaped in an endless path through the heating station.

61. The method according to claim 60, characterized in that the magnetic foil is magnetized upstream of the heating station and demagnetized downstream of the heating station or has its magnetization homogenized.

62. The apparatus for carrying out the method according to one of the claims 54 to 61, characterized by: a) a supply store for a carrier foil; b) a treatment station with a magnetizing unit and a heating unit; c) a receiving store for taking up the marking device; d) guide elements and a drive for feeding the carrier foil from the supply store through the treatment station to the receiving store.

63. The apparatus according to 62, characterized by: a) a coating station for applying a homogenizingly magnetized coating to the carrier foil; b) guide elements and a drive for feeding the carrier foil from a supply store through the coating station and the treating station to the receiving store.

64. The apparatus according to one of claims 62 to 63, characterized in that the magnetizing unit has a magnetic foil which is magnetized and that the guide elements effect a meeting of the carrier foil and the magnetic foil upstream of the treating station.

65. The apparatus according to claim 64, characterized in that a supply store for the magnetic foil is provided upstream of treatment station and a receiving store is provided downstream of the treating station, and that the magnetizing unit is disposed between the supply store and the heating unit.

66. The apparatus according to claim 64, characterized in that the magnetic foil has an endless configuration and is passed by the guide elements through the heating unit together with the carrier foil.

67. The apparatus according to claim 66, characterized in that the magnetizing unit is disposed in the travel direction of the carrier foil upstream of the heating unit and produces a nonhomogeneous magnetic field and that a quenching device is provided between the heating unit and the magnetizing unit for demagnetization or homogenizing the magnetic field.

68. The apparatus according to claims 66 or 67, characterized in that the magnetic foil for stretch over a support roll which is associated with the treating station.

69. The apparatus according to claim 62, characterized in that the treating station is associated with a support roll over whose roll periphery the carrier foil is advanced based the treating station and that the roll periphery is of a magnetizable configuration.

70. The apparatus according to claim 69, characterized in that the magnetization unit produces a nonhomogeneous magnetic field and that a quenching device for demagnetization or homogenization of the magnetic field.

71. The apparatus according to claims (69, 70), characterized in that the roll periphery has a magnetizable coating.

72. The apparatus according to claims 70 or 71, characterized in that the quenching unit and the magnetization unit follow one another in the direction of rotation of the support roll in the region of the support roll which is free from the carrier foil.

73. The apparatus according to one of claims 62 to 72, characterized in that the treating station has heating devices for local heating.

74. The apparatus according to claim 73, characterized in that the heating device or devices have at least one laser.

75. The apparatus according to one of claims 73 to 74, characterized in that the treating station has a magnetizing device for producing a homogenized magnetic field.

76. The apparatus according to claim 75, characterized in that the treating station has a heating unit for producing a homogeneous temperature field as well as a magnetizing unit for producing a nonhomogeneous magnetic field.

77. The apparatus according to one of claims 62 to 76, characterized in that a further coating station is provided for applying a protective layer to the second layer.

78. The apparatus according to one of claims 62 to 77, characterized in that the coating station has one or more vapor deposition units.

79. The apparatus according to one of claims 62 to 77, characterized in that the supply store is formed as a supply roll and the receiving store as a storage roll.

80. The apparatus of claims 63 to 79, characterized in that the coating station and the treating station have carrier rolls over whose roll peripheries the carrier foil is fed.

81. The method defined in one of claims 6 to 12, characterized in that at least one homogeneous magnetized layer (133) is formed and the layer (133) is locally so subjected to an ion bombardment that it is locally caused to have a variation in its easy axis and/or its remanence.

82. The method according to claim 81 characterized in that the ion bombardment is effected with the aid of a focused ion beam.

83. The method according to claim 81, characterized in that the ion bombardment is effected on an areawide basis and in the region of the carrier (132) a nonhomogeneous electric charge field is produced.

84. The method according to one of claims 81 to 83, characterized in that an electrically chargeable carrier is charged electrically nonhomogeneously prior to the ion bombardment.

85. The method according to claim 83, characterized in that an electrically chargeable underlay (129) is nonhomogeneous electrically charged and that the carrier (132) placed on this underlay (129) and the ion bombardment is effected on the combination of the underlay (129) and the carrier (132).

86. The method according to claim 85, characterized in that a carrier foil is drawn from a supply and after a coating is brought together with a continuously improved charging foil (129) and both are subjected to ion bombardment.

87. The method according to claim 86, characterized in that the carrier foil and charging foil are separated after the ion bombardment.

88. The method according to one of claims 86 or 87, characterized in that the charging foil is drawn from a supply and then charged and after the ion bombardment is taken up in a store.

89. The method according to one of claims 86 or 87, characterized in that a charging foil (129) is circulated as an underlay through an ion bombardment station (113) and the charging foil (129) upstream of the ion bombardment station (113) is charged and downstream of the ion bombardment (113) is discharged or has its electric homogenized.

90. The method according to one of claims 81 or 82, characterized in that a carrier foil and masking foil are continuously drawn from respective supply and brought together and that the ion bombardment is then effected from the side of the masking foil and the masking foil is then separated from the carrier foil.

91. The method according to claim 90, characterized in that the masking foil after being withdrawn from the supply and before being brought together with the carrier foil is provided with cutouts.

92. The apparatus for carrying out the method according to one of claims 81 to 91, characterized by: a) a supply store (131) for a carrier foil (132); b) an ion bombardment station (113) for the bombardment of the layer (133); c) a receiving store (136) for the marking device; d) guide elements (115) through (123) and a drive for displacing the carrier foil (132) from the supply store (131) through the ion bombardment station (113) to the receiving store (136).

93. The device according to claim 92, characterized by: a) a coating station (112) for applying a homogeneous magnetized layer (133) to the carrier foil (132); b) guide elements (115) through (123) and a drive for feeding the carrier foil (132) from the supply store (131) through the coating station (112) and the ion bombardment station (113) to the receiving store.

94. The apparatus according to one of claims 92, 93, characterized in that the ion bombardment station has a focused ion beam and a control device is provided for the targeted control of the ion beam.

95. The apparatus according to one of claims 92, 93, characterized in that an electrically chargeable carrier foil is passed through the ion bombardment station and is provided with a nonhomogeneous electric charge by a charging unit.

96. The apparatus according to one of claims 92, 93, characterized in that the ion bombardment station has an electrically chargeable charging foil passed through which is provided with a nonhomogeneous electric charge and that the guide elements effect a meeting of the carrier foil and charging foil upstream of the ion bombardment station.

97. The apparatus according to claim 96, characterized in that a supply store is provided for the charging foil upstream of the ion bombardment station and a receiving store is provided downstream of the ion bombardment station and a charging unit is provided for the nonhomogeneous charging of the charging foil between the supply store and the ion bombardment station.

98. The apparatus according to claim 96, characterized in that the charging foil has an endless configuration and is based via the guide elements together with the carrier foil through the ion bombardment station and that the charging device in the travel direction of the carrier foil is provided upstream of the ion bombardment station and a quenching device is provided between the ion bombardment station and the charging device for discharging or homogenizing the electric charge.

99. The apparatus according to claim 98, characterized in that the charging foil for stretching over a support roll which is associated with the ion bombardment station.

100. The apparatus according to one of claims 92, 93, characterized in that the ion bombardment station (113) is associated with a support roll (116) over the roll periphery (129) of which the carrier foil (132) is passed through the ion bombardment station (113) and that the roll periphery (129) is chargeable with an electric charge whereby a charging unit (128) is provided for charging the roll periphery (129) and a quenching device (130) is provided for discharging or homogenizing the electric charge of the roll periphery (129).

101. The apparatus according to claim 100, characterized in that the roll periphery has a coating chargeable with an electric charge.

102. The apparatus according to one of claims 98 to 101, characterized in that the discharging unit 130 and the charging unit (128) are provided one after the other in the rotation direction of the support roll (116) in a region of the support roll (116) which is free from the carrier roll (132).

103. The apparatus according to one of claims 92, 93, characterized in that the ion bombardment station has a masking foil based therethrough and that the guide elements effect a meeting of the carrier foil and masking foil upstream of the ion bombardment station in such manner that the ion bombardment is effected from the side of the masking foil and that the guide elements separate the carrier foil and masking foil downstream of the ion bombardment.

104. The apparatus according to claim 103, characterized in that between a supply store for the masking foil and the meeting of the masking foil and carrier foil a mask forming station is proposed for producing cutouts in the masking foil.

105. The apparatus according to claim 104, characterized in that the mask forming station has a laser burning device.

106. The apparatus according to claim 104, characterized in that the mask forming station has a control device for varying the position of the laser burning device.

107. The apparatus according to one of claims 92 to 106, characterized in that a further coating station (114) is provided for applying a protective layer 135 on the layer 133.

108. The apparatus according to one of claims 93 to 107, characterized in that the coating stations (112, 114) have at least one vapor deposition unit (124, 125).

109. The apparatus according to one of claims 92 to 108, characterized in that the supply store is configured as a supply roll and the receiving store as a storage roll.

110. The apparatus according to one of claims 93 to 109, characterized in that the coating station and the ion bombardment station have carrier rolls over the roll peripheries of which the carrier foil is fed.

111. A method of reading a marking device according to one of claims 1 to 5 with the aid of a magnetic field sensor, characterized in that the coding is subjected to at least two reading processes whereby one reading process is effected in a zero field and a reading process is effected in an external magnetic field or the reading processes are effected in different external magnetic field.

112. The method according to claim 111, characterized in that one reading process is carried out with saturation magnetization.

113. The method for reading marking devices according to one of claims 1 to 5 with the aid of magnetic field sensor characterized in that at least one reading process is carried out in the remanence.

114. The method for reading marking devices according to one of claims 1 to 5 with the aid of magnetic field sensor characterized in that at least one reading process is carried out in the flux change at the boundary between two magnetic regions is detected.

115. The method for reading marking devices according to one of claims 1 to 5 with the aid of magnetic field sensor characterized in that at least two reading processes are carried out without an external magnetic field and that the coding before a reading process is magnetized in one direction and before a further reading process is magnetized in another direction up to saturation.