JPH04504479A - A code carrier, a method for evaluating information on the code carrier, and a coding system using the code carrier for product identification. - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Code, code system for @code's 0 t- The present invention relates to an article consisting of magnetic, magnetizable and/or electrically conductive materials arranged subsurface. Arranged under the surface of code carriers and products for evaluation of identification codes, magnetic, magnetized a cord made of conductive and/or electrically conductive material and having a geometrical arrangement comprising a cord; This article relates to a method for evaluating carrier information. Moreover, the present invention a] A predetermined shape, for example, a change in the cavity 5 through hole and/or the axis of the cord carrier. at least one of magnetic, magnetizable and/or electrically conductive material having a cross-section of also one code carrier b) Few (one electromagnetic field source) C) at least one electromagnetic field for measuring stray electromagnetic fields generated by the code carrier field sensor Coding system for product identification with a code carrier arranged below the surface layer In order to evaluate stray electromagnetic fields formed by electromagnetic fields for product identification by a fixed shape, e.g. a cavity, a through hole and/or a lateral shape that varies between the axis of the cord carrier. The use of said code carrier consisting of a magnetic, magnetizable and/or electrically conductive material having a cross-section Concerning business.

Many industrial products are manufactured in large quantities, making it difficult to monitor product production at every stage. Optimize the manufacturing process and eliminate non-compliance with tolerances or other manufacturing errors. This is necessary in order to identify in a timely manner an impending stoppage of a production machine. be.

In this way, the manufacturing process (turnaround time) can be optimized and scheduled repairs Reduce downtime of manufacturing machines during operations and reduce the number of products that fail quality inspection However, costs can be saved in this way.

Continuous monitoring of products should be carried out (applying appropriate markings or codes to products at the start of production). It means to do something. In that case, it is possible to read and record this l[ at each manufacturing stage. can. This makes it possible, for example, to record the time points of individual manufacturing steps for each product. Wear. This allows cost optimization of the manufacturing process.

A number of product recording or production monitoring systems are known.

Problems arise when reading barcodes during manufacturing. This is because stains occur or This is because the barcode may be hidden during construction or destroyed by processing operations.

The electronic marking system consists of an electronic logic circuit, to which information can be transferred without contact. For example, it can be read out by infrared radiation or inductively. In this case Iwa The popular ``chip card'' is well known. This is a high safety system, so It is also used for manufacturing monitoring. In this case the information is a programmable storage chip It can be read out to the chip via a high frequency system. this is It is an extremely versatile and intelligent system. suitable for that purpose There are read and write functions that can be protected by protocols. This type of system is The drawback is that it is relatively expensive to produce in large quantities. Therefore, the chip is fixed to the product. In many cases, chips are fabricated as a result of thermal and mechanical loads. It does not withstand the building process, so this system is not robust enough.

DE-AI is a magnetoresistive transducer for reading coded information on postage meters. -3222789. In this case the code is the circumference of the electrical resistance in the magnetic field. This is realized by a change in the magnetic field (“magnetoresistance”), and the combination of magnetoresistance and the so-called soft magnetic convergence device. The arrangement of the positions forms the code, in which case the shape and magnetization of the code carrier do not matter. The disadvantage of the system is that its arrangement and required space make it unsuitable for coding mass-produced products. Don't do it. Furthermore, measurement of magnetic resistance is almost impossible without contact.

The identification system for mosieres moved along the transport path is DE-At- 3729740. In this case, by arranging permanent magnets, A magnetic code is realized, and the code is represented by north and south poles. This system uses magnetic The geometry of the stone does not matter, the reading element consists of a Hall element and transmits The north and south poles are distinguished by voltage. In this case, the Hall voltage sent out is closely related and decreases with about the third power of the distance, so if strict distance tolerances are adhered to, Magnets cannot be juxtaposed in close proximity, where magnetic field measurements yield reproducible descriptions , otherwise they would influence each other. These types of products containing permanent magnets are It cannot be manufactured individually or easily (integrated) into each mass-produced product.

Similar electronic systems for detecting binary codes on transfer line workpieces is known from DE-^1-3331694. In this case, the code information is It is written to any EFROM (erasable programmable ROM). special inside An inductive operating system consisting of a relay is used for energy supply and data transmission of the EFROM. Ru. In this case, using EPROM in a large number of mass-produced products is expensive and Environmental conditions that exist during manufacturing, such as a pressure of 2m degrees, may destroy the EFROM. That is a drawback. In addition, as a general rule, active components should not be used as code storage devices. As such, it requires a power supply, which poses significant limitations.

DE-^1 Method and apparatus for detection and identification of articles with coded labels -2712016. The purpose of this known prior art is parcels and mailing bags. The objective is to facilitate automatic sorting of In this case the cord is made from a thin magnetic strip or wire. Become. By dividing the magnet strips or grouping the plurality of magnet strips into groups, The code is realized. Another method is to use materials with different coercive field strengths. Is Rukoto. However, it is difficult to make this code cheap enough to use in mass-produced products. The disadvantage is that it is impossible due to manufacturing technology. Known reading devices are AC-supplied excitation Consists of a coil. As is well known, this excitation coil is used to generate a homogeneous magnetic field. It has Helmholtz geometry. A balanced detection coil is used to detect the The hysteresis loop can be determined by measuring the voltage amplitude of different cord materials. In this case, the code is detected by measuring the phase shift. This system measures The signal generated depends on the speed of the moving article. Therefore, for example, on a conveyor belt Only conditionally suitable for moving products.

DE is a method for displaying and evaluating digital codes attached to carriers using ferromagnetic materials. -^1-2437547. In this case the cords are combed together Made of intricate ferromagnetic strips or strips. However, mass production of this code carrier The disadvantage is that the manufacturing technology is too complex to realize for the product. 3 The presence of the cord is detected by a ferromagnetic E-shaped core with several coils.

In that case, precise positioning of the read head is required and external voltages may be introduced. Another disadvantage is that no special measures are taken to prevent "erroneous" bits from occurring.

A ferromagnetic carrier is attached to the object to be identified, and the reading head is used to read the code at a distance. Magnetically encoding this carrier from a distance is disclosed in Austrian Patent No. 309111. known by.

Due to the attachment of magnetic carriers, this type of method is susceptible to interference without suitable safeguards. water.

Several patent publications deal with coding for skis, for example. this corresponds to the coding of mass-produced products 1 For example, on the surface of skis, it is visible under ultraviolet light. It is known to print signs that In this case, in particular, the processing facility of which this sign consists So-called barcodes are commonly used for product identification during processing, e.g. grinding or normal wear. The disadvantage is that it is erased as in the case of using a code.

By magnetically attaching a cord to the edge made of ferromagnetic material (iron), the ski Coding is known from Saiichi Stria Patent No. 390005 ( "Magnetic region"). However, in that case, unless special materials are used, this code The disadvantage is that it is susceptible to external interference, especially demagnetization. Also this code is edge It is destroyed every time there is a grinding operation. A cheap product that is fixed and persists in every individual product. A coding system is desirable for many purposes. Also coding element hidden within the product, i.e. protected from direct view or at least beneath the surface layer. It would be convenient if it could be arranged as follows. thereby further improving the quality of the product after sale. You can also check the ``gk history''. This is true, for example, in the case of guarantees and insurance technology. For example, this is useful in the case of theft. Therefore, the present invention provides an identification method during the manufacturing process. It features sufficient mechanical stability to withstand damage when installed inside or outside the product. The product is well protected from being easily destroyed when used for its intended purpose. The object is to provide a code carrier of the kind mentioned at the outset. Finally, the present invention , the code carrier is formed as inexpensively as possible in connection with use in mass-produced products, and +111 The purpose is to be able to read out with a simple and reliable device. In this case, it is used for mass-produced products. A reasonably simple structure of the code carrier and a simple and reliable code reading method are required for use. One thing is extremely important. In this case it is possible to use cord carriers for mass-produced products. The hood must be reliably identified and coded as a result of operation or environmental influences. Great care must be taken that it is almost impossible to destroy the child In order to solve the problem, the code carrier based on the present invention is roughly as follows. In other words, it uses a stray electromagnetic field that changes along the axis of a plane parallel to the main axis of the cord carrier. In order to achieve this, the cord carrier has a through hole, a cavity or a varying cross section. this In this case, in combination with simple stray electromagnetic field measurement, a reasonably stable and inexpensive cord carrier can be used. It can be used. This cord carrier is characterized by a relatively simple geometric shape , moreover, the proposed reading method of the code carrier or the code information allows the reading device to It is possible to reliably identify them without having to operate them precisely. In this case the code carrier contains The use of stray electromagnetic fields for the identification of stored codes is sensitive to distance. Since the number is relatively small, a simple electromagnetic field sensor can be used to sort the codes. Wear. Also, this kind of simple cord carrier can be used during the manufacturing process for mass-produced products such as skis, shoes, etc. Particularly easy to integrate into varnish rackets etc., depending on the planned material selection A high degree of stability is also guaranteed during the manufacturing process. Especially by measuring stray electromagnetic fields. The above code carriers can be evaluated, for example by resonant tuning or magnetoresistance. Eliminates the tedious balancing and tuning required when measuring coupled magnetic fields Become. In this case, the cord carrier can be formed very simply as a plate or film. In particular, in the case of products with multilayer structures, attachment to the product is particularly difficult. Also the board A cord carrier can be formed from a conductive metal-plastic emulsion adhered to a wire. This type of code carrier can then be applied particularly inexpensively to mass-produced products during production, for example by printing methods. You can. In addition, in this case, this kind of conductive film can be protected from mechanical destruction afterwards. conductive metal-plastic emulsion or magnetic powder plastic coated on the substrate to protect It is preferable to protect the milky lotion with a coating layer after drying. Evaluate changing stray electromagnetic fields In order to achieve this, the cord carrier is particularly simply arranged in at least two planes parallel to the principal axis. with a through hole, void or varying cross-section; The changing cross section is formed regularly. In this case regular formation of one plane is independent of the speed at which the read head is moved relative to the code carrier and the result of the evaluation. Bringing you the benefits of clock tracking.

To further reduce the risk of deliberate destruction, the cord carrier should be arranged so that it is not visible from the outside. It is preferable to have a structure with rows. In that case the code carrier is an integral part of the product. Preferably, it consists of a component or a component of a product. Arranged below the surface layer of the product a geometric shape containing a cord, consisting of magnetic, magnetizable and/or electrically conductive material; The evaluation method according to the invention of information of a code carrier having i5 is generally characterized by the following: Suppose that In other words, a stray field that generates an electromagnetic field and changes parallel to the main axis of the code carrier. It measures and evaluates electromagnetic fields. High frequency alternating current electricity is used to generate the above electromagnetic field. field, in which the wax current formed in a conductor within a high-frequency alternating electric field acts inversely on the electric field. , thereby reducing the measured electric field strength. Therefore, the method based on the present invention is preferable. Alternatively, the cord carrier is exposed to a high-frequency alternating current electric field, and the eddy current generated in the cord carrier detecting the relationship between changes in the high-frequency electric field caused by It is characterized by When using a magnetic field, use a soft magnetic material as a code carrier, This soft magnetic material is exposed to a magnetic field, and the generated location-dependent stray Mm field is detected by a magnetically sensitive sensor. It is preferable to measure with sa. In this case, the magnetic field is a permanent magnet magnetic field or a DC magnetic field. and generating a periodic alternating magnetic field corresponding to a preferred embodiment of the present invention. You can also. The at least partially permanently magnetic cord carrier has a location-dependent stray magnetic field. Of course, it is also possible in principle to apply a field and measure it with a magnetically sensitive sensor. Ru. However, this type of permanent magnetic code carrier is characterized by extremely low reliability. be. This is because the stray magnetic field of such a permanent magnet is changed by a correspondingly high external magnetic field. There is a risk that the code you originally entered may be lost or changed due to be. Stray electromagnetic fields of the code carrier that vary depending on the electromagnetic field are separated It is particularly preferable to measure with a sensor and send the measured signal to a common evaluation circuit. This greatly improves the reliability of the evaluation of reading operations. Furthermore, the present invention provides an electronic device for identifying a product using a code carrier arranged under the surface of the product. Predetermined shapes, e.g. cavities, penetrations, for evaluating stray electromagnetic fields formed by magnetic fields. magnetic, magnetizable with a cross section that varies with respect to the axis of the bore and/or the cord carrier and/or the use of cord carriers made of electrically conductive materials. In that case the above code The carrier can be placed, for example, in sports equipment, in particular skis, hitting equipment for ball games, etc. ．． The structure according to the invention as a whole provides a) a predetermined shape, e.g. with a cross section that varies with respect to the axis of the pore and/or cord carrier, magnetic, magnetizable and/or at least one cord carrier made of electrically conductive material. b) at least one electromagnetic field source; C) at least one electromagnetic field for measuring stray electromagnetic fields generated by the code carrier field sensor A coding system for product identification is created with The element alone It is particularly easy to realize and put into practical use, and when combined, it has a high degree of reliability. , robustness, and mechanical stability.As already mentioned before, this kind of code Preferably, the coding system comprises a plate or a film as a code carrier. So Within the scope of this coding system, the code carrier is made of conductive metal plastic. It is particularly easy to form with magnetic emulsion or magnetic powder plastic emulsion. This further simplifies insertion or application of the card. Coding system like this Once formed, the cord carrier can be sprayed by a simple printing process or by using a template. This is because it can be served as a snack. As a result, especially in the case of mass-produced products, the cost will further decrease. The cord carrier has through holes, voids or changes in at least two planes parallel to the main axis. It has a cross section and has through holes, voids or varying cross sections arranged in one plane. It is preferable to improve the coding system of the present invention so that In this way, electricity Independent of the speed at which the magnetic field source or electromagnetic field sensor is moved relative to the code carrier A clock track is created for evaluation that allows for accurate stray electromagnetic field measurements. In this case the electromagnetic field drift moves relative to the code carrier for scanning the entire code. It is preferable to generate a possible electromagnetic field. In this case, the scope of the above coding system is using a periodic alternating magnetic field as already mentioned above for the reading method. is preferable. According to a preferred refinement of the coding system, the electromagnetic field sensor sensor or magnetoresistive element, and furthermore, to improve accuracy, It is preferable to provide one big up coil for both. However, depending on the conditions, The backup coil itself can also be used as an electromagnetic field sensor. AC electric field If used, a code reading device for the code carrier consisting of an electromagnetic field source and an electromagnetic field sensor is provided. a high frequency electromagnetic field oscillator for exciting an eddy current in the code carrier; A code signal that can evaluate the attenuation of high-frequency electromagnetic fields related to the geometry of the code carrier. improve the coding system to include an output stage for converting That is preferable. By forming the coding system in this way, the code The evaluation of the code can be carried out particularly easily by excitation of eddy currents in the code carrier. Alternatively, a code reading device for a code carrier consisting of an electromagnetic field source and an electromagnetic field sensor. A high-frequency electromagnetic field oscillator for exciting eddy current in the code carrier, a detection coil system, Attenuation of high frequency electric fields related to the geometry of differential amplifiers, comparators and code carriers The evaluation device is configured to include an output stage for converting the It can also be done. Next, the present invention will be explained in detail based on an embodiment shown schematically in the drawings. Figures 1 to 6 of the drawings shows a schematic diagram of various code carriers. Figures 7 and 8 show the reading of two types of code carriers. Schematic diagram, FIG. 9 is a principle diagram of an eddy current head, and FIGS. IO to 20 are various reading processes. 21 shows a block diagram of an embodiment of the electronic evaluation device. vinegar. The code information is stored in changes in the cross-section or generally in a special shape of the code carrier. There is. Shapes, e.g. cross-sections, contours or an axis in a plane along at least one spatial axis of the surface or parallel to the main axis of the code carrier; A change in direction forms a chord. Be sure to allocate signals correctly regardless of scan speed If there is a "clock track" parallel to the "code track" so that It is further advantageous for complete identification of code patterns. Examples of the shapes of cord carriers are shown in Figures 1 to 6. Figure 1 shows the spatial transport 2 or parallel to the principal axis. A metal plate l is shown which has a coding in the form of a protrusion 3 on its plane axis. Therefore Cody in this case the spatial alignment of the protrusions 3 along the spatial axis 2. derived from this This diagram schematically shows the bit pattern. In this case, the cord carrier is a conductive metal or soft magnetic made of magnetic or hard magnetic material. The code stored in the shape change is always It is detected by the spatial distortion of the induced or stray electromagnetic fields. No. In the first case, the presence of protrusion 3 is confirmed by a clear enhancement of the attenuation of the eddy current, and in the second case or in the third case, detecting protrusions based on stray electromagnetic fields using an electromagnetic field sensor. Can be done.

According to FIG. 2, the code carrier is an object having an array of ribs 5 representing a code on its surface. It is 4. In this case too, the code carrier may be a conductive metal or a soft magnetic material depending on the reading method. made of magnetic or hard magnetic material.

FIG. 3 shows a cross section of a metal plate 6 with bulges 7 at predetermined intervals for coding. The figure shows that conductive metals are suitable as cord carrier materials in this case. thus The flat part of the plate 6 is within the detectable range of the eddy current sensor (not shown in detail). If is outside the range, the eddy current method is suitable for reading.

Another advantageous embodiment of a code carrier of this kind is 2, for example a metal foil 8 as shown in FIG. Consists of. Metal foil consists of a good conductor. Coding is holes or voids 9 and 9 Consists of ゛. Although the holes are circular in FIG. 4, they may have any other shape. The optimal shape of the hole adapts to the shape and type of sensor used to read the code information. The presence of holes must be detected, for example by a commercially available eddy current sensor. of the hole The size and reachable bit density per unit area of the code from what distance Let me point out that it depends on whether we have to read the distance.If this distance is large, The diameter of this hole must be as large as possible when a metal like this is punched through. Foil is a particularly inexpensive, easy-to-use cord carrier (which is stored at the end of the structure shown in Figure 4). The row of holes adjacent to the edge is the clock track for synchronization, and the information is transferred to another large It is housed in 9th grade.

FIG. 5 shows another form of cord carrier similar to that in FIG. 1, the plate lO having projections 11 on both sides. and is coded with it. In this case, one side is called the "cord track". and the other side can be used as a "clock track". in this case The code carrier can also consist of an electrically conductive metal and a soft or hard magnetic material.

FIG. 6 shows an embodiment consisting of discs 12 in which code carriers are arranged sequentially, each disc A suitable round bar is used, which carries an overhang 13 along its periphery and whose arrangement forms a cord. A similar function can also be obtained by molding. In this case as well, The body can be made of conductive metal and soft or hard magnetic materials.

It is not necessary to use a separate attached member as a cord carrier; any suitable Create a code by appropriately changing the external shape of an existing product part made of material (metal or magnetic). It is particularly advantageous to use this for recording codes by making it digitized.

What all these embodiments of the cord carrier have in common is that the cord carrier is attached to the workpiece. be easily and invisibly integrated, or at least protected and integrated beneath the surface layer. This is something that can be done. The cord is removed at the beginning of production, e.g. by machining the cord carrier. Once it is determined, it cannot be changed or destroyed, which is not allowed. Only then will the code be destroyed. In that case, there is always obvious damage to the product. The modification of the code is also obvious.

In this way, undesired operations or operations with fraudulent intent can be easily detected. Wear.

Reading of the code carrier always takes place without contact. As already mentioned before, the code The carrier is inside the product and directly (not on the second surface, the material used in the product is used) We especially point out here that it limits the possible reading methods, so e.g. The code on the code carrier can be detected even if metal is present or through the metal. A reading method is possible and will be explained later.

The code on the code carrier can be detected in various ways. Applied read The law depends inter alia on the material of the cord carrier and its environment, e.g. the material used in the product. Exists. For example, conductive cord carriers made of copper are caused by eddy currents. Can be scanned for stray magnetic fields. If the cord carrier is made of soft magnetic material e.g. iron or If made of permalloy, scan the shape change or code through the stray magnetic field. be able to. If the cord carrier is made of soft magnetic metal material, magnetic induction method Can be combined with current method. This increases reading accuracy. @I have one temperament Generally offers the advantage of being able to detect codes even in the presence of other metals .

Let us recall that stray electromagnetic fields have, in principle, the following causes: stray electromagnetic fields It can be triggered by eddy currents or magnetically. Read in either case Operation is performed by scanning stray electromagnetic fields. In one case, the high frequency alternating electric field eddy current is generated in the metal conductor. Here the metal conductor is the code carrier. There The melting current generated by the Using a commercially available sensor that measures the damping as well as the reduction in the amplitude of the oscillator or can be determined as the deviation of the resonant frequency of the oscillator . In that case, the attenuation of the eddy current that occurs in the cord carrier depends on the distance between the sensor and the cord carrier. It depends.

In another case, the shape-dependent stray electric field of a soft or hard magnetic cord carrier can be Record the electric field measurement in rad. These methods are closely related via Maxwell's equations It is clear that there is a relationship, but there is a fundamental difference from the point of view of the physical mechanism. These reading methods will be explained in detail.

When scanning stray electromagnetic fields caused by eddy currents, the code carrier Any metal is suitable. It is preferable that the metal is a good conductor, but research It has been revealed that the conductivity values are only slightly dependent on the distance of commercially available sensors. or no effect. Similarly, the [soft] magnetic state of the metal cord carrier is also Rapidly changing the power level ゛Has little effect on the threshold, but The sensitivity, or distance dependence, of commercially available eddy current sensors can be significantly improved by using an auxiliary detection coil. can do good. Adapting this sensing coil arrangement to the shape of the sensor's emission lobe It won't happen if you don't let it happen.

A schematic diagram of a reading device for stray electromagnetic fields caused by eddy currents is shown in Figure 7. The head 14 is passed along the cord carrier 16 in the direction of the arrow 15 or fixed. The code carrier 16 is passed along the reading head 4. To improve sensitivity Additionally, one or more small detection coils can be placed directly at the end of the oscillator emission head. Can be stored. The speeds customary for belt conveyors do not interfere with the reading operation 6. FIG. 7b shows a plan view of the measuring device according to FIG. 7a. Reference number 17 is code carrier 1 6 holes are shown, and the arrangement of the holes forms a code.

FIG. 8 shows an arrangement similar to FIG. 7, with the cord carrier having lateral overhangs as shown in FIG. Consists of a metal plate with The distance between the plate and the sensor required for code identification The height h of the lateral overhang is 1. The discrimination limit of the sensor indicated by the broken line in Fig. Let me add that the threshold must be smaller than x+h. When using the auxiliary detection coil to increase sensitivity as described above, increase S. However, in that case, the spacing between adjacent r bits, i.e., the structure overhang, may also be It won't work unless you make it bigger.

Figure 9 shows the basic structure of a device for reading stray electromagnetic fields caused by eddy currents. The scanning principle is based on a contactless electronic proximity sensor, the reading device is essentially an oscillating vessel! 8. It consists of a trigger 19 and a switch output 2o of the amplification logic circuit. sensor and co The spacing of the code carriers is determined approximately by the diameter of the sensor emitter.

I9, for example, a differential amplifying the signal generated by the aforementioned auxiliary detection coil 48. Dynamic amplifiers can also be used. This signal reaches the comparator and the comparator signal and an adjustable reference signal and sends out a signal (“Bit J”) or is not sent out, in which case the evaluation is still carried out in a suitable logic circuit (20).

The resonant circuit coil of the oscillator 18 generates a high frequency electromagnetic field 21 emanating from the working surface of the sensor. live. This high-frequency electromagnetic field penetrates deep into the metal body, which in this case constitutes the code carrier 22. Confirm the to the code carrier by an alternating electromagnetic field according to Maxwell's equations, Eddy currents, indicated schematically at 43, occur. Eddy currents are generated so that the primary electromagnetic field is shielded. The direction is set. The strength of this eddy current depends on the frequency of the alternating electromagnetic field, the conductivity, and In the case of magnetic materials, it is also related to their magnetic permeability. By appropriate selection of the material of the cord carrier Therefore, in principle, the sensitivity of the entire system can be adjusted. However, experiments show that However, commercially available eddy current sensors are generally too insensitive to be used in accordance with the material. be. The generation of this eddy current robs the oscillator of energy. For this reason A change in amplitude or a change in resonant frequency occurs in the output of the oscillator, which triggers 19 and The output stage 20 converts it into a logic signal.

9 shows at least one auxiliary detection coil 48, the system includes at least two coils. preferably consists of two coils, so that the induced signals generated in the coils are antiparallel and equal. , that is, the coils are wound or arranged so that they cancel each other out. metal cord carrier When a body is placed near the oscillator, it changes the strength and direction of the eddy field. By that The symmetry of the detection coil system changes.

A signal is generated due to the code carrier. In this way, for example, holes in metal foil can be detected. The sensitivity can be significantly increased.

The strength of this eddy current, and with it the strength of this attenuation, greatly depends on the distance between the sensor and the metal. depends on. Some of the geometric shapes forming the code exceed or reach the sensitivity limit S. If you don't.

The scanned portion can then be converted into a code (for example, see Figure 8). ), thus making it possible to detect, for example, rips or bumps on the metal code carrier [ For example, in Figure 2, Figure 3, Figure 5, or Figure 6], changes in the three-dimensional cross section of the metal code carrier also affect the sensitivity limit. If the field crosses this cross-sectional change, it should be detected as a code with an eddy current sensor. Can be done. Another approach is to identify the presence or absence of metal if it is within the sensitivity limits. Is Rukoto. Thus, for example, if the diameter of the hole corresponds approximately to the diameter of the sensor, Can detect holes in metal foil. The auxiliary detection coil also detects small diameter holes. information density can be increased overall. High frequency alternating electromagnetic field Since the penetration depth is small, very thin metal foils can be used. This thing is manufactured This is particularly advantageous in terms of construction technology. Suspend the cord in a conductive lacquer or plastic It is also possible to realize this using metal powder and detect it using eddy current.

Multiple eddy current sensors to store as many bits per unit area as possible It is advantageous to juxtapose the 2 or n side-by-side holes 2 or n eddy current can be detected by a sensor, in which case the minimum spacing of the sensors is approximately comparable to its diameter. Must win.

If there are no other metals in the product in the immediate vicinity of the code carrier, eddy currents can be used to read the code. It can be used for However, in that case, the code carrier has a sensitivity limit S inside, all other metal parts must be arranged outside the sensitivity limit S, provided that Magnetically detectable code carriers are particularly advantageous in this case. In other words, soft magnetism and and hard magnetic cord carrier cords made of other metal materials such as aluminum, copper, etc. This means that it is possible to penetrate through the area and detect it.

In the case of soft magnetic materials, the stray electromagnetic field, which depends on the geometry of the code carrier, is penetrated to the outside. code can be detected. Various for reading codes in soft magnetic materials There is a technical solution. According to the coding method carried out by special molding, The code carrier is magnetized by an externally generated excitation magnetic field. This magnetic field is a direct current magnetic field or is an alternating magnetic field.

Figure 1O is the reading for a magnetically generated stray field using magnetization by a DC magnetic field. FIG. 11 shows the signal obtained in this way. For example, a DC magnetic field is It is generated by the permanent magnet 23. A field coil through which direct current flows is used instead of a permanent magnet. It can also be used instead.

A permanent magnet or The magnetic permeability μ of the material used for the cord carrier, for which the field coil has to be designed, is 0. It is particularly advantageous if the magnetic field strength H is selected in such a way that a maximum value of . in addition A significant improvement in the sensitivity of the system is thus obtained. The product and with it the cord carrier 24 It is moved through the magnetic field in the direction of arrow 25. Due to the high magnetic permeability of the material, external The field lines of the magnetic field cause significant distortions to the particular shape of the code carrier. magnetic field lines An example of the distribution of is schematically shown in FIG.

The measurement of the magnetic field line distribution peculiar to the shape of the cord carrier over the long plane can be carried out using a Hall sensor, for example. It will be held on the 26th. Instead of Hall sensors, other suitable sensors such as magnetoresistive elements can be used. , magnetoresistive sensors, etc. may also be used.

Further voltages can also be used here for code detection. This voltage is The code carrier is passed through an auxiliary pickup coil, thus changing the magnetic flux and thereby When generating a signal, it is induced in the pickup coil (for example, Figure 13). 12, a field coil is shown at 27, and when the code carrier 28 is moved inside the field coil, 1 The magnetic field lines shown in the figure are formed and can be used to read the code. Wear. In particular, customary suitably sensitive magnetic field sensors are suitable in this case; The size of the (action surface) is the spatial dimension of the void, bulge, or cross-sectional change that represents one bit. It's almost equivalent (I have to play it.

When using an alternating current electromagnetic field as the primary electromagnetic field, a so-called pickup coil is used. It is left to read the code. In this case too, the magnetic field generated is The field coil must be designed to be homogeneous over the average. The strength of the magnetic field H is selected to obtain the highest value of magnetic permeability μ,,□ of the material used for the carrier. It is particularly advantageous if you do so. AC electromagnetic fields to avoid shielding effects due to eddy currents. The frequency of the control must be relatively low (i.e. f>4(Jkhz) A significant improvement in the sensitivity of the system can be obtained by appropriately selecting the electromagnetic field and its frequency. Figure 13 shows the sequence left for this purpose, and Figure 14 shows the resulting readout signal. The cord carrier 30 is moved in the direction of arrow 31 in the primary coil generating an alternating electromagnetic field, as shown in the figure. move in the direction. A voltage is generated in the pickup coil 32. Its amplitude is a line of force It is proportional to the density and the specific shape of the cord carrier. The code carrier sends out the signal ``compensated J pickup system'' characterized in that the voltage is now proportional to the magnetization. The simplest embodiment is preferably to use antiparallel windings on one axis. There are two coils. The "pure" magnetic field signal is thereby canceled out. In this way, Highly reliable position resolution and identification of adjacent bits without the use of “racks” Can be done. Special attention must be paid to the position resolution of the pickup system, The larger the average spacing between the cord carrier and the pickup coil, the worse the position resolution will generally be. It's good. Obtaining high positional resolution through special molding of the pickup coil Can be done. This causes the "virtually" generated magnetic field to become larger at the "bit" location. , suddenly becomes zero outside, the pickup system has high positional resolution.

Another arrangement is a bipolar compensated coaxial system with a position resolution higher than 5. But this In this case, the position resolution can be further improved by installing an auxiliary coil. Wear. On the other hand, the length of the pickup coil is the three-dimensional dimension of the cross-sectional change that makes one bit. If the system is determined to the maximum by It is advantageous in terms of measurement technology to use a zero-period alternating electromagnetic field.

This is because by using frequency and phase sensitive amplifiers the two-code signal can be This is because the signal-to-noise ratio can be significantly improved. The amplitude of the code signal is The read signal changes with the tempo of the shape change of the code carrier, so the read signal is based on the code of the code carrier. Reproduce. It is particularly advantageous to use integrators for signal processing. believe by it The signal voltage becomes independent of the frequency of the exciting electric field and the motion of the object. The integral required here and the integrator must have two negative feedbacks with two different time constants 1+ and tl. In order to integrate the AC voltage for one period, the time constant t is smaller than the period T. The time constant t, which must be greater than tl, must be larger than tl at the time of integration. integration of offset voltages or other long-term disturbances that are extremely disturbing. An example of an integrator that can be used that must compensate for pressure is the hysteresogelaph. Ru. The output signal is again proportional to the magnetization and the cross section of the code.

In this case too, a Hall sensor can be used instead of a pickup coil. . Hall sensors measure stray electromagnetic fields that vary with shape.

It is particularly advantageous to use a pick-up system in combination with a stray field measuring sensor. two Connect appropriate measurement electrodes to the measurement system. Two independent systems identify one “bit” only when it is recorded as actually belonging to the code. Thus the disturbance The safety of the system against the effects of

Figure Is, 16 shows another configuration of the readout method, where single side or multiple excitation A soft magnetic yoke 33 with a magnetic coil is used. The cord carrier is a soft material with ribs. Made of magnetic or permanent magnet material. The order of the ribs represents the code, ribs 34 and 3 5, when the cord carrier is soft magnetic, by passing through the magnetic yoke 33. A portion of the code carrier is magnetized. Conversely, in the case of a permanent magnet cord carrier, this cord carrier The body magnetizes the soft magnetic yoke.

In either case, the change in magnetic flux is caused by at least one secondary coil of the same yoke. Measured by touch. The excitation coil can be powered with direct and/or alternating current . The type of current chosen depends on the type of current used to detect the stray field decay that forms the code. Depends on the sensor. In this case, the strength of the current is determined by the material of the yoke. Also the circuit The current must be set such that the total permeability of the It is also possible to use field-sensitive sensors, such as Hall sensors and magnetic field measuring plates. child They are located in the gap between the cord carrier built into the product and the soft magnetic yoke. reading The encoded code is a position-resolvable scanned magnetic field or stray electric field that varies within this gap. This is revealed by measuring the magnetic field. It is the magnetic resistance caused by the ribs This is the result of fluctuations in In that case, the output signal represents a bit string whose amplitude corresponds to the code. No. occurs.

Experiments have shown that the above code can be set up successfully on an aluminum plate. can do. Frequencies that are not very high (f < 10 kHz, especially 100 kHz) There is no problem in using an excitation alternating current (less than Hz).

Two soft magnetic code carriers can be stored and read simultaneously on the front and back of the product. (double the stored bit density), the mutual spacing d of the code carriers is If the distance between the carrier and the soft magnetic yoke is larger than y, no effect will appear (see FIG. 17).

As shown in FIG. 18, a composite measurement system consisting of a measurement coil 44 and leg irons of the soft magnetic yoke 33 It is particularly advantageous to use an electromagnetic field sensor, for example a Hall sensor 26. . Two Corollaries 6 (Only when we indicate the presence of one bit do we know that it is actually a code. and recorded. The safety of the system against unwanted disturbance voltages is thus significantly increased. I can't stand it. The secondary coil is indicated by 45 and can be operated with direct current and alternating current at the same time. made. The secondary coil 44 is wound antiparallel.

The use of permanent magnetic cord carriers in mass-produced products only makes sense if this is cheap It is righteousness. A hard magnetic film like that used for checks is considered.

Coding can be done in several ways.

a) a primary cord which first completely magnetizes the strip of hard magnetic film in the direction of axis 47; (see Figure 19), the stray magnetic field along the edge By measuring the (demagnetizing force) code is recorded. In this case, a suitably small hole It is particularly advantageous to use an electric sensor.

b) Straying of the gap of the soft magnetic yoke before attaching the strip of hard magnetic film to the product magnetized in the direction of the magnetic field (see 11I in Figure 20), in which case the width of the magnetized area is Depends on the cap.

The stray magnetic field in this magnetized area is then detected by an external magnetic field sensor (Hall sensor, pickup). It can be recorded in In this case, increase the recorded product code. The code carrier must be set and read at a correspondingly large interval. The area must be magnetized, the width of the magnetized area is such that the code can still be read. This corresponds approximately to the possible interval. In this case, the clock information is 1 bit (N-S stripe). It is determined by calculation from the width of the

C) A combination of a) and b) is also possible. In that case periodic voids may occur, for example The presence of N or S pole means bit rlJ or rOJ. . In this embodiment, the speed of passing the code carrier (product) along the reading head is It is advantageous if the degree is small. In that case, for example, by omitting the neutral zone, the information Density can be increased.゛Figure 21 shows the block diagram of the electronic evaluation device for the measured signal. The control unit 36 (high frequency sensor, excitation current, Hall at least one sensor 37 (eddy current sensor).

pickup coil, Hall element). The current coming from the sensor is sent to amplifier 3 8 (signal processing) and converted to a digital signal by analog-to-digital converter 39. and transferred to computer 40 (code identification, evaluation, data storage). Beep When recording codes with a pickup coil, use a hysteresogelaph to record the signal. As mentioned above, it is recommended to use multiple measurement systems (e.g. pickup coil and electromagnetic field). It is particularly advantageous to use both sensors at the same time. Multiple measurement systems measure one bit Only when reporting is it transferred to the combiator as actually read. Ko Code identification, evaluation and data storage take place in the ambiator. On the other hand, the feed control section 4 1, the driving of the sensor 36 is also controlled via the position identification section 42.

We will now highlight a few important aspects of the invention.

The present invention is used for characterizing (coding) products manufactured in large quantities. . This method is mainly used for monitoring the manufacturing process, and also for safety, quality and assurance operations. was established for. One feature is that conductive materials (metals) and magnetic (soft or hard) storage of the code in a code carrier made of magnetic) or magnetically capable material. material The choice of material is decisive for the reading method and even for the readability of the code. Ru. Cords are caused by changes in the shape of the cord carrier, changes in cross section 1 changes in contour, lip or Cavities, holes or suitable metal-plastic emulsions such as "conductive lacquers" It consists of patterns created by These are stray electromagnetic fields caused by eddy currents. or detected via geometrically determined stray magnetic fields. Multiple independent reads It is redundant due to the combined use of methods. The appropriately detected position-dependent analog measurement signal , can be converted into digital information equivalent to a code.

The code elements are mechanically and thermally robust, invisible or hidden from the outside, and are are largely insensitive to environmental influences, especially those in or in contact with the product. It is preferable that the product be stored in a container and be inseparably connected to the product.

The code carrier can take any form. Match its outline to the shape of the product be able to. High flexibility in molding is also a feature of the present invention. conductive or magnetic A part of a product consisting of a material with a cross section, contour 1 surface change or void of any shape By providing a section, it can be used as a cord carrier.

The cord carrier is a permanent magnetic member, preferably a hard magnetic film, or a plastic magnetic powder emulsion. Or it can consist of a metal-plastic emulsion. If there are other conductive parts in the processed product. It is advantageous for the magnetic code carrier to be detectable even when the magnetic code carrier is detected. The conductive member This also applies if the wafer is arranged directly above or below the card carrier.

The workpiece, which consists of one or more eddy current sensors and includes a cord carrier, is In the case of a code detection device that is passed along a sensor, eddy current is A flow occurs.

Whether eddy current actually occurs depends on the distance between the eddy current head and the metal cord carrier. It depends a lot. Now, the cord carrier has special molding (cross section, thickness, holes, etc.). The code is realized. This causes variations in the distance between the eddy current head and the cord carrier. occurs, logic rOJ (interval is too large) or logic “1” (interval is small enough) occurs. Changes in the properties of the high frequency oscillation circuit due to the eddy current generated in this way are Used as a signal for code detection.

In the case of a detection device for a code contained in a magnetic code carrier, a piece of soft magnetic material with a special shape Create a code based on the shape (cross section, surface, etc.). Position-dependent strays representing code The electromagnetic field is scanned by an electromagnetic field sensitive sensor. Passing products with cord carriers through the coil system By moving the cord, the pickup voltage thus generated is used to It is possible to record position-dependent stray electromagnetic fields that represent .

The magnetizing magnetic field can be a periodic alternating magnetic field. Position-dependent strays representing code The electromagnetic field is detected as a periodic AC voltage by a position-resolved pickup coil system. . In this case frequency and phase sensitive enhancements are used for signal processing resulting in a good signal-to-noise ratio. Another way, preferably using a width divider, is to integrate the signal. in addition The frequency of the excitation field therefore no longer influences the magnitude of the measurement signal.

The position-dependent stray electromagnetic field representing the code is removed by a magnet-sensitive sensor, e.g. a Hall sensor or a magnet. It can also be detected as a periodic AC voltage using a resistance element. Occurs periodically Alternating voltages make the use of frequency- and phase-sensitive amplifiers particularly advantageous for signal processing. . A good signal-to-noise ratio can be obtained.

The cord contained in the 5 soft magnetic cord carrier is determined by a special shape and is made into a soft magnetic yoke. It can be detected by The code is partially through monitoring the power consumption of the coil or Pass through 1gi resistance using another auxiliary secondary coil or by magnetic field sensitive sensor. It is detected by A magnetic field sensitive sensor responds to changes in stray magnetic fields in the gap.

When the code carrier includes a permanent magnetic member, it is appropriately molded or magnetized to be coded. A stray magnetic field generated by a permanent magnet that represents a cord and changes depending on its position is replaced by a soft magnet. a magnetic yoke (with an induction coil above it) or a suitably small magnetic field sensor (Hall sensor) It can be scanned with

Preferably, the sensing read head is arranged for contactless reading. reading The size of the head is generally the spatial dimension of the feature that describes one pin, e.g. Preferably, the arrangement of the heads corresponds approximately to the change in cross-section of the code carrier and Can be adapted to the shape and size of the product and can therefore be freely selected6 The spacing depends on the geometry and size of the bit J, and also according to basic physical laws. is determined by the spacing dependence of stray electromagnetic fields.

The optimum shape of the void or cross-sectional change representing "r bit" depends on the action range of the sensor used. directly related to the shape of

Due to the relative movement of the cord carrier and the cord in question generally along the main axis containing the cord. The code of the code carrier can be determined by In that case, a suitable decomposition of the code For this purpose, the speed is known or a "clock track" is used. but multiple By arranging several sensors appropriately, it is possible to scan all code carriers at once. , if there are a number of sensors corresponding to the information density, we can measure the relative motion between the code carrier and the code. This can be abolished and the code read time can be reduced.

FIG. 4 FIG.5 FIG.6 FIG. 12 FIG. 15 FIG. 16 FIG. 17 FIG. 19 S　N　N FIG. 20 international search report 11111～---9pO/^τ9110OO], 3

Claims (1)

[Claims] 1. Product categories arranged below the surface and consisting of magnetic, magnetizable and/or electrically conductive materials Cord carrier for basis value of cord (1, 4, 6, 8, 10, 12, 22, 24, 28, 30, 35, 46), the axis of the plane parallel to the main axis of the cord carrier (2, For the evaluation of stray electromagnetic fields varying in the direction of Through holes, voids or varying cross sections (3, 5, 9, 9', 11, 13, 17, 2 4, 34). 2. Forming the cord carrier as a plate (4, 6, 10) or as a film (8, 16, 46) The code carrier according to claim 1, characterized in that the code carrier comprises: 3. Conductive metal-plastic emulsion or magnetic powder plastic with a code carrier adhered to the substrate The cord carrier according to claim 1, characterized in that it is made of a milky lotion. 4. Cord carrier (8, 10, 24) penetrates in at least two planes parallel to the main axis with holes, voids or varying cross-sections (9, 9', 11) and through-holes in one plane. , a claim characterized in that voids or changing cross sections are formed regularly. 3. The code carrier according to 1, 2 or 3. 5. Code carrier (1, 4, 6, 8, 10, 12, 22, 24, 28, 30, 35 , 45) are arranged so as not to be visible from the outside. 4. The code carrier according to any one of 4. 6. Code carrier (1, 4, 6, 8, 10, 12, 22, 24, 28, 30, 35 , 46) is an integral part of the product or consists of a component of the product. A code carrier according to any one of claims 1 to 5, characterized in that the code carrier has the following characteristics: 7. arranged below the surface of the product and consisting of magnetic, magnetizable and/or electrically conductive materials; A code carrier with a geometrical shape containing a code (1, 4, 6, 8, 10, 12, 2 In the information evaluation method of 2, 24, 28, 30, 35, 45), an electromagnetic field is generated. and code carrier (1, 4, 6, 8, 10, 12, 22, 24, 28, 30, 35 , 46) is characterized in that it measures and evaluates the stray electromagnetic field that varies roughly parallel to the principal axis. How to make it a sign. 8. The code carrier (22) is exposed to a high frequency electromagnetic field (21), which generates in the code carrier Detects changes in high-frequency electromagnetic fields caused by eddy currents in relation to the properties of high-frequency oscillation circuits 8. The method according to claim 7, characterized in that: 9. A code carrier (24, 28, 30, 35) made of soft magnetic material is exposed to a magnetic field. , measuring the generated position-dependent stray magnetic field with a magnetically sensitive sensor (26, 32). 8. The method according to claim 7, characterized in that: 10. 10. A method according to claim 9, characterized in that a periodic alternating magnetic field is generated. 11. Code carriers (1, 4, 6, 8, 10, 12, 22, 24 , 28, 30, 35, 46) by at least two independent sensors. (26, 32; 26, 44) and send the measured signal to a common evaluation circuit. Method according to any one of claims 7 to 10, characterized in that: 12. Shaped with electromagnetic fields for product identification by means of code carriers arranged under the surface of the product. Predetermined shapes such as cavities, through holes and/or or cross sections varying with respect to the axis of the cord carrier (3, 5, 9, 9', 11, 13 , 17, 24, 34) of magnetic, magnetizable and/or electrically conductive material. Code carrier (1, 4, 6, 8, 10, 12, 22, 24, 28, 30, 35, 46 )Use of. 13. a) The predetermined shape example relates to the cavity, the through hole and/or the axis of the cord carrier. (3, 5, 9, 9', 11, 13, 17, 24, 34) at least one cord carrier consisting of a magnetic, magnetizable and/or conductive column material ( 1, 4, 6, 8, 10, 12, 22, 24, 28, 30, 35, 46) b) at least one electromagnetic field source (14, 18, 23, 27, 29, 33) and c ) at least one electromagnetic field sensor for measuring stray electromagnetic fields generated by the cord carrier; Sa (18, 26, 32) 14. Coding system for product identification having: Plate the cord carrier (4, 6, 10) or a film (8, 16, 46) Coding system according to claim 13. 15. The code carrier is a conductive plastic emulsion or magnetic powder plastic adhered to the substrate. 14. The coding system according to claim 13, characterized in that it comprises a milky lotion. 16. The cord carrier (8, 10, 24) penetrates in at least two planes parallel to the main axis. It has a through hole, a void or a cross section (9, 9', 11) and penetrates in one plane. A claim characterized in that holes, voids, or varying cross sections are regularly formed. Coding system according to item 13, 14 or 15. 17. An electromagnetic field source (14, 18, 23, 27, 29, 33) is applied to the code carrier. Claims 13 to 16, characterized in that the electromagnetic field generates a relatively displaceable electromagnetic field. A coding system according to any one of the above. 16. characterized in that the electromagnetic field source generates a periodic alternating magnetic field (27, 29, 33) 18. The coding system according to claim 17. 19. Particularly, the electromagnetic field sensor consists of a Hall sensor (26) or a magnetoresistive element. 19. A coding system according to any one of claims 13 to 18, characterized in that the coding system comprises: 20. A claim characterized in that the electromagnetic field sensor consists of a pickup coil (32). 19. The coding system according to any one of claims 13 to 18. 21. A code reading device for a code carrier equipped with an electromagnetic field wave and an electromagnetic field sensor is provided. An oscillator (18) of a high-frequency electromagnetic field (21) that excites a thin current in the code carrier (22). ), the trigger (19) and the high-frequency electric wave related to the geometry of the code carrier (22). It consists of an output stage (logic circuit 20) that converts the attenuation of the magnetic field into an evaluable code signal. Coding according to any one of claims 13 to 17, characterized in that: system. 22. A code reading device for a code carrier comprising an electromagnetic field source and an electromagnetic field sensor is provided. , an oscillator (1) of a high-frequency electromagnetic field (21) that excites eddy currents in the code carrier (22). 8), a detection film system (48), and a detection film system (48). A differential amplifier, a comparator, and a code carrier (22 ) into a code signal that can be evaluated. and an output stage (logic circuit 20). A coding system according to any one of the above.