FI113570B - Procedure for manufacturing a product sensor and product sensor - Google Patents

Description

113570

A method for manufacturing a product sensor and a product sensor

The present invention is directed to a method for manufacturing a product sensor, wherein a wire pattern is formed on the product sensor to provide an electrical oscillation circuit, and at least one fuse for deactivating the electrical vibration circuit. The invention also relates to a product sensor comprising a vibration circuit formed by conductor patterns and at least one fuse for deactivating said electrical vibration circuit.

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By product sensor in this specification is meant an electrical connection formed in connection with a product or product package or on a stand which can be used for product identification, for example as product protection to prevent theft (anti-theft sensor), and / or as a means of identification. The product sensors formed on a separate support can be advantageously affixed by gluing or stitching to the product, but other methods can also be applied.

20 Product Protection Sensors are used with products to prevent any potential product theft. The products are then affixed with a product sensor used as a product protection sensor, and at the exits of the stores there are sensors for detecting such a product protection sensor, if it has not been deactivated in motion. The product protection sensor is deactivated, that is, made inactive when the product is properly paid at the checkout. Such a deactivated product · · * 'security sensor is generally not detected by the sensors, thus avoiding unnecessary alarms.

t · 30 Such product sensors for use as product protection sensors and / or sensors are generally made of a thin plastic film which is coated on both sides by laminating an aluminum film to the surface of the plastic film. Preferably, the dye is transferred onto the aluminum foils using exemplary gravure printing. The dye provides the desired: patterning of the metal over the metal film, whereby etching the metal, for example by etching, leaves a metal pattern forming the desired electrical circuit. Such an electrical circuit in a product sensor is usually comprised of a resonance circuit (oscillation circuit) consisting of one or more coils and a capacitor. The purpose of the resonant circuit in the product protection sensor is e.g. the fact that the sensor can detect the existence of this resonant circuit if the product protection sensor is not passivated. 5 In detection applications, the resonant circuit transfers e.g. electrical energy to the product sensor and transmitting information between the product sensor and the product sensor reading and / or writing device.

In order for the product sensor to be sufficiently reliably detected by the reader device 10 with current standard size product sensors, for example 40 mm x 40 mm, the resonance circuit must have a very high coefficient of performance. The industry-standard practice requires a Q of Q value of at least 70. However, since the product sensor manufacture is intended to be implemented in a cost-effective and high volume manner, the practical characteristics of the coil conductor need to be somewhat compromised. In practice, this means that the conductivity of conductors in products on the market is of the order of bulk aluminum or even slightly lower. This conductivity typically achieves a Q value in the range of 70-80 for product sensors on the market.

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The passivation of the product protection sensor may be performed, for example, by: providing a breakthrough on the capacitor plates of the product protection sensor; which shortens the capacitor plates and thus eliminates the resonant circuit.

The problem with such passivation is e.g. the fact that the breakthrough is not necessarily permanent, whereby the product sensor can be reactivated as an example / by bending the product sensor. The problem with such product sensors that can passport with electric field is, for example, the following: the fact that automatic packing and labeling lines typically have Λ static discharges, which can cause product sensor 30 to be deactivated already at the packaging or labeling stage.

, '··. Product sensors are also known in which passivation is performed by breaking the fuse formed in the resonant circuit. The cut-off is implemented by applying a substantially resonant frequency electromagnetic field 35 to the product sensor, which provides a high current to the resonant circuit. This current also passes through the fuse, and since the fuse has been designed to burn across a given 113570 3 current, the fuse can usually be cut off by this electromagnetic field. One problem with such a fuse solution is that the manufacturing tolerances of the fuse in the prior art manufacturing processes are relatively high, so that the current required to break the fuse may not be within the allowable range for different product sensor individuals. In some prior art product sensors, this fuse is made with a separate conductor which is attached to conductors formed in a series resonant circuit. Such a so-called. the wire punching method is expensive and the production capacity 10 low compared to, for example, the aforementioned etching product sensors, in which the fuse is also made by a similar method.

The operation of the fuse is based on the fact that it is heated and burned by the current flowing in the circuit 15. This mechanism of the fuse causes it, the fuse to degrade the Q value of the product sensor. Thus, in a typical prior art product sensor, the fuse cannot be added, for example, by pressing a conductive paste without lowering the Q value below the accepted level. However, in breakthrough product sensors, the passivation mechanism does not significantly reduce the Q value, since passivation is not based on the use of resistive components.

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Another electrotechnical problem with product sensors is that the difference between the magnetic fields that the product-25 Turin must endure and the product sensor must pass through is very small. Typically, the product sensor must withstand a magnetic field of the order of 0.9 A / m and correspondingly a magnetic field of the order of 1.5 A / m should suffice for passivation. Thus, for the fuse dimensioning, this requires precise control of the resistance characteristics ...: 30, low resistance and the balancing of the total resistance of the oscillation circuit between the different components. The low resistivity requirement is due to the fact that the stronger field must induce enough '> * higher current to the circuit than the weaker field will induce.

:. ·: 35 There are also some problems with the manufacture of the product sensor such as the amount of material in the fuse. In order for the inductive field inductive current to be sufficient to burn the fuse, the amount of fuse material must be very high.

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small compared to, for example, what the amount of material in the coil conductor should be. In addition, this amount of fuse material must be very precisely controlled. The smaller the amount of material that can be made, the lower its resistance load relative to the other current circuit and the less the fuse will lower the Q value. In addition, the more precise control of the amount of material can better predict the current required for a fuse to cross-burn, i.e., make the fuse burn more reliable. By improving the fabrication tolerance of the fuse, the fabrication tolerances of the coil and capacitor can be somewhat relaxed.

Another manufacturing technology problem relates to the placement of the small amount of material needed in the fuse into the product sensor, which is manufactured on roll-to-roll machines and on a film with an easy throw of up to 15%.

Yet another third manufacturing problem relates to adhesion and contact resistance between two different interfaces. In practice, the only possible coil conductor materials are copper and aluminum due to e.g. 20 of the required high Q values. However, copper and aluminum form a natural oxide layer very easily, which increases the need; ; *: frictionless fuse resistance value without actually being a cross-burning element.

A further fourth manufacturing problem relates to the mechanical .// properties of the fuse. Because the product sensor is typically flexible and is roll-to-roll, the manufacturing material must be flexible. In addition, the electrical conductivity properties of this material must not change significantly due to the moderate bending effect. Due to the aforementioned manufacturing and electrotechnical problems, the product sensor cannot be manufactured using only etching technology.

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The manufacture of capacitors also causes problems in the manufacture of product sensors. One reason for this is that a sheet-like material with good heat resistance must be used as the substrate for the capacitor • Λ: 35. For such materials, the loss coefficient is typically of the order of 0.01 or higher.

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Based on the problems described above, it is clear that producing a product sensor of sufficient quality and reliability in a cost effective manner is difficult.

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It is an object of the present invention to provide a method for manufacturing a product sensor so that the properties of the product sensor are improved as compared to prior art product sensors. It is a further object of the invention to provide an improved product sensor for a feature bridge. The invention is based on the idea of forming a fuse and at least a coil structure of an electric resonance circuit in discrete modules which are interconnected by means of a thermoplastic film or, for example, isotropic or anisotropic paste. The module comprising the fuse may also include part of an electrical resonance circuit. More specifically, the method of the present invention is essentially characterized in that at least two modules are formed, the first module being formed on a first substrate which is an insulator, a first metallization layer 20 formed on the first substrate and conductor patterning at least electric resonant circuit and forming a second module on a second substrate which is an insulator for forming a metallization layer on the second substrate, and providing at least a fuse to the metallization layer, further providing electrical interfaces to the first and second modules 25 to provide electrical connection between the overlapping first and second modules; module is connected by: placing the first module and the second module overlapping at least partially and a bonding layer 30 between the first and second modules to provide the first and second modules with each other. The product sensor according to the invention is v. Mainly characterized in that the product sensor comprises at least two modules, the first module being formed on the first one; a substrate which is an insulator that a first metallization layer 35 is formed on the first substrate and a first metallization layer: a conductor pattern is formed to provide at least an electric resonant circuit coil, and a second module is formed on the second substrate 113570 and at least a fuse is formed in the metallization layer, the first and second modules further comprising electrical interface surfaces for electrical coupling between the overlapping first and second modules, and said at least two modules being interconnected by at least partially overlapping the first and second modules; an adhesive layer between the second module arranged to provide the first and second modules with one another.

In a method according to a preferred embodiment of the invention, the at least two modules are interconnected by means of a thermoplastic film.

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The present invention achieves significant advantages over prior art manufacturing methods and product sensors. When applying the method according to the invention, no compromise is needed between the various functional units of the product sensor, but both the electric resonant circuit and the fuse can be implemented with the best possible properties. In addition, the method of the invention can achieve easy modifiability in the manufacture of a product sensor, since different modules can be combined with each other]; * * so that the end result is a product sensor that is as close as possible to the desired characteristics. Due to the modular structure, different substrate materials can be used in the coil and in the fuse making. As a result, capacitor *: can be fabricated during coil manufacture, since it is possible to use in the coil manufacturing path; · 30 mm. low-loss polyolefins. By the method of the invention, product sensors can be manufactured relatively quickly and at relatively low connection temperatures. Low connection temperatures mah; make it possible to use materials with lower temperature resistance, which can often be, for example, dielectric properties better than materials with higher temperature resistance. Modules: in some applications can be contactlessly connected to each other, thus avoiding connection resistance. 113570 7 also achieves lower joint resistance and good joint reliability when using contact joints.

Also, there is no need to use a double layer structure in the manufacture of the capacitor, since different plates of the capacitor can be realized, if necessary, by forming one plate in the first module and the other plate in the second module. When the modules are combined, the capacitor boards are in substantially the same position in the different modules, making the capacitor operational. In this way, a uniform junction capacitance can be obtained for the capacitor to be shaped.

When applying the process of the invention, various manufacturing techniques, such as additive processes, can be used to make the coil. Substractive, i.e. etching, techniques can also be used.

Various techniques for making a fuse, such as the use of selective resistors, pattern evaporation, printing with conductive pastes, resistors exposed to film and / or a discrete component fuse, can also be used in the manufacture of the product sensor of the invention.

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In the process according to a preferred embodiment of the invention, the required joint tolerances are not as stringent as in the prior art processes, whereby the yield is improved.

In the manufacture of the product sensor according to the invention, it is possible to use printable, laminable and / or coating (e.g., extrusion coating) dielectrics.

: · 30

The method according to the invention is easily and cheaply automated. A further advantage of the process according to the invention is that the excess material costs are relatively low.

t I t * · * t 35 The invention will be described in more detail below with reference to the appended claims

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113570 8 illustrates a top view of a first module of a product sensor according to a preferred embodiment of the invention, Fig. 1b shows a top view of a second module of a product sensor according to a preferred embodiment of Fig. 2 shows a side view of Fig. 1a and 1b. Figures 3a shows a top view of a first module of a product sensor according to a second preferred embodiment of the invention; 15 Figure 3b shows a top view of a second module of a product sensor according to a second preferred embodiment of the invention; the electrical counter-coupling of the product sensor, Figure 5 illustrates a step of combining modules in a method according to a preferred embodiment of the invention, and method breakdown based on capacitor structure.

»· * *. The following describes a method according to a preferred embodiment of the invention, wherein a first module 3 of a product sensor 2 according to the invention is fabricated on a first substrate 1, for example a self-adhesive laminate. Figure 1a is a top view of the first module 3 : · 'Viewed. Similarly, a second module 5 of a product sensor 2 according to the invention is fabricated on a second substrate 4. Figure 1b shows a second module 5 of a product sensor 2 according to an embodiment of the invention, viewed from above. It should be noted in this connection that, for the sake of clarity, the accompanying figures 1a-4 are not necessarily correct. The substrate materials used in the first 3 and the second module 5 are preferably flexible, whereby the finished product sensors 2 can, for example, be rolled up and used in a wide variety of products.

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Although the manufacturing method according to the invention will be described in the following mainly with regard to the manufacture of one product sensor 2, it is clear that the method according to the invention can simultaneously produce several product sensors 2.

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Preferably, the manufacture of the first module 3 begins by forming a first metallization layer on the first substrate 1 by evaporation or other suitable method. For example, copper or aluminum is used in the evaporation of this first metallization layer and the evaporation thickness is typically in the order of 100 nm to 500 nm. In the next step, a so-called. printing of an electrolytic resistor, for example by gravure printing. This electrolysis resistor is patterned such that, where no conductive materials, such as a conductor, coil, or capacitor plate, are to remain in the first module 3, an electrolytic resistor is applied.

Subsequently, the conductors can be grown preferably by electrolysis. At this point, a second metal / 25 deposition layer is formed at the sites of the metallization layer that does not have the electrolysis resist. Thereafter, a desired conductor pattern is formed on the first metallization layer of the product sensor, the first :. However, this metallization layer is still short-circuited at this stage.

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After the growth step, the electrolysis resist and the redundant portion of the first metallization layer under the electrolysis resist must be removed. When aluminum is used in the evaporation step, both the Λ electrolysis resist and the metallization layer can be removed, for example, with lye. If 1 * 1: copper is used as the vaporizing agent, the removal of the evaporated metallization, i.e. etching at the electrolytic resist, can be carried out in a separate bath 35, as is known per se. After removal of the excess metal, the first module 3 is ready to be used as a manufacturing part of the product sensor 2. The example of Figure 1a is for this first one

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10 a coil L formed in module 3, a single plate 6a, 6b of two capacitors C1, C2 and the necessary wiring for interconnecting the coil L and the capacitor plates 6a, 6b.

In some applications, wiring and / or other electrical connections may be provided to one side of this first substrate 1. These may be formed either in conjunction with the above steps as a two-layered process or as a separate step. For example, when using a dual-layer structure, the capacitor 10 may be implemented with this first substrate 1.

The manufacture of the second module 5 can be carried out, for example, by a sub-active fabrication method such as etching. At least one fuse F is formed in this second module 5. To achieve this, a metallization layer is formed on the surface of the substrate material, for example in the same manner as described above for the fabrication of the first module 3 metallization layer. A fuse mask is applied to the surface of this metallization layer at the point where the fuse F is to be implemented. In some applications, more than one fuse may also be used, whereby a fuse mask is formed correspondingly to the fuses to which these fuses: · are desired.

• he! The fuse mask is made of a material that withstands the action of an electrolytic resin remover, whereby the portion of the first metallization layer applied to the fuse mask does not dissolve.

• »♦ • a j If necessary, the fuse mask can be removed from the second module 5 without significantly affecting the remainder of the electrical connections of the 30 module 5. Figure 1b shows another module 5 selected: *. mine. In this example, the second module 5 comprises a fuse F, second plates 7a, 7b of capacitors C1, C2 and the necessary wiring to: connect the fuse and the capacitor plates in an appropriate manner.

The following describes the steps of combining 113570 11 modules of a method of manufacturing a product sensor according to a preferred embodiment of the invention. The purpose of this module combination step is to combine the first 3 and the second module 5 to provide a finished product sensor 2. Referring now to Figure 5, this step of combining the modules is illustrated. It is assumed that the en-5 first 3 and second modules 5 are manufactured as a long (continuous) rib, with the web having modules 3, 5 in a row and / or parallel. In Fig. 5, the first web 8 comprises first modules 3 and, accordingly, the second web 9 comprises second modules 5. For example, a thermoplastic film 10 is placed on the surface of the first web 8, which 10 is also preferably fed as its own web. The attachment may be accomplished by any method known per se, for example by transfer laminating or extrusion. This step is illustrated by arrow 11 in Figure 5. The second web 9 is then placed on the thermoplastic film 10 (arrow 12). Thus, at this point, the second web 9 is secured to the surface of the first web 8 by means of a thermoplastic foam 10, whereby the desired electrical connections to the product sensors 2 are formed at the points of the connected modules 3, 5. The webs 8, 9 must be aligned with each other as closely as possible so that the operation of the coupling is sufficiently reliable. However, this alignment is relatively easy to accomplish in a module assembly step as described above.

The width of the thermoplastic film web is preferably substantially * 1 · '.... the same as the width of the first web. However, it should be noted that; that if the width of the first 3 and the second module 5 in the transverse direction of the web is not the same, the width of the thermoplastic heat web in the transverse direction is preferably substantially the same as the finished product sensor 2 overlapping the first 3 and the second module 5. width of the area. The thermoplastic film 10 is thus intended to: ·: · 30 preferably be positioned between the first module 3 and the second module 5; all over this missed area.

Depending on the application, the thermoplastic film having electrical properties may be either completely insulated or may be at least partially: electrically conductive.

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To carry out the coupling according to Fig. 4, no electrically conductive connection is required between the first module 3 and the second module 5, but the coupling is formed by capacitors C1, C2. The first plate 6a, 6b of the capacitors C1, C2 is formed in the first module 5 and the second plate 7a, 7b is formed in the second module 5. Thus, when the modules 3, 5 are in place, these different capacitor plates 6a, 7a; 6b, 7b at each other. When the thermoplastic film 10 is at least insulated with these capacitor sheets, capacitors C1, C2 are formed at the respective locations. Figure 2 10 is a side elevational view of a finished product sensor 2 in which the modules 3, 5 are connected to one another. In this embodiment, a thermoplastic film is used which is an insulator throughout.

The above described contactless interconnection of modules 3, 5.

15 This avoids contact resistance in the contacts. Figures 3a and 3b show the modules 3, 5 of a product sensor 2 which establish an electrical contact between the contact substrates 6c, 7c of the modules 3, 5 to form an electric resonant circuit.

In applications where an electrically conductive connection is required between the modules 3, 5, a thermoplastic film which is electrically conductive or formed at least at the required positions to be conductive may be used. Some examples of such thermoplastic films include 8773 and 8783 (Z-Axis Adhesive Films 8773 and 8783). In these, the conductivity is ·) only in the thickness direction, not in the plane direction. Such electrically conductive thermoplastic films are referred to as anisotropic conductive film (ACF). In this case, even if the thermoplastic film is placed against the surface of the module 3, 5, it does not affect the internal connections of the same module 3, 5, but only:; for connections between modules 3, 5. Even if contact connections are needed-. Even between the modules 3, 5, the connection resistances can be made relatively small. Typically, for a joint area of 2 mm x 2 mm: / a resistance gap of less than 0.5 Ω can be achieved.

35:, · If necessary, openings may be made in the thermoplastic ACF film 10 at positions where coupling between modules is not desired. Second

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As an alternative, the thermoplastic ACF film 10 is coated with an insulating material at locations where the conductivity should not be or should be as low as possible.

The actual attachment of the modules 3, 5 to each other is accomplished by heating the thermoplastic film 10 and, if necessary, applying pressure to the film. Under the influence of heat, the thermoplastic film 10 becomes softer. After heating, cooling of the thermoplastic film 10 is performed, whereby the thermoplastic film 1010 hardens and forms a strong bond between the first 3 and the second module 5.

After the connection of the modules 3, 5, ready-made product sensors 2 have been formed which comprise the desired electronic circuit. This electrical circuit 15 comprises e.g. for anti-theft applications, the RLC circuit. The coil L is a planar conductor loop and the capacitor C is formed of two or more substantially planar plates, which is known per se.

In a manufacturing method according to another preferred embodiment of the invention, the fuse F is preferably formed in the second module 5 as follows. The necessary conductors and the capacitor plate (s) 7a, 7b are made on the surface of the second module, for example by etching.

However, at the point where the fuse is made, the wire is cut off. : '' The vaporization mask is then pressed elsewhere on the surface of the second module 5 except where the fuse F is to be vaporized. After this, the fuse is evaporated with, for example, copper or aluminum. Thereafter, other necessary layers may be formed in the second module 5 and the connection of the modules may be performed.

Although the above method for producing modules as fabricated is described above, it is clear that other methods may also be used in the manufacture of modules 3, 5. However, it is essential that the modules are bonded together by means of a thermoplastic film 10 or the like, and; ; that the first module 3 has a coil L and the second module 5 I · has a fuse F.

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The bonding of the modules to each other can also be accomplished by other means than by means of a thermoplastic film 10. For example, the modules 3, 5 may be glued to each other using a low loss laminating adhesive or using extrusion lamination or an isotropic or anisotropic paste. In this case, the paste can be dispensed, for example, in connection with the connection of the module to the antenna path.

The process according to the invention can be divided, for example, according to the structure of the condensers C1, C2. A structure having two capacitors in series has already been described (Figure 2). In this case, the layer between the modules, which was formed by means of a thermoplastic insulating film, was used as the insulation of the capacitor. Other insulation possibilities include the use of a substrate 1, 4 of the first 3 and / or 15 second modules 5, a printed dielectric, a transfer laminated dielectric and / or an extruded dielectric. With the above options, a contactless connection between modules 3, 5 could be used. However, if there is only one capacitor, one electrical connection between the modules can be made contactless by means of capacitor plates, whereby the other connection is accomplished by providing an electrically conductive contact between the modules 3, 5. Then, the insulating layer of the capacitor: · can be implemented using the first 3 and / or the second. the substrate 1, 4, the printed insulating layer (dielectric), the transfer laminated insulating film and / or the extruded insulating layer of module 5. The electrically conductive contact 25 may be formed in the second connection by, for example, a · double-sided structure in either the first 3 or the second module · · '} 5. It is also possible for the conductive contact to be formed by a printed, transfer laminated or extruded dielectric so that it does not extend at least to another; · 30 contacts. Yet another embodiment of the capacitor (s) is that a separate component is used, whereby contact connections are formed between the modules 3, 5. The capacitor (s) may be mounted, for example, by a flip chip technology. Fig. 6 is a diagram showing the distribution of method 35 according to the capacitor structure shown above.

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It will be understood that the present invention is not limited to the above embodiments, but may be modified within the scope of the appended claims.

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Claims (24)

A method of manufacturing a product sensor (2), wherein the product sensor (2) is provided with a wiring pattern to provide an electric oscillation circuit (L, C1, C2), and at least one fuse (F) to deactivate the electrical the oscillation circuit (L, C1, C2), characterized in that at least two modules (3, 5) are formed, of which the first module (3) is formed on a first substrate (1) which is an insulation, the first substrate (1) forms a first metallization layer, and the first metallization layer is provided with a conduit pattern to provide at least one coil (L) for the electrical resonant circuit, and the second module (5) is formed on a second substrate (4). ), which is an insulation, that a metallization layer is formed on the second substrate, and the metallization layer is provided with at least one fuse (F), that the first (3) and the second module (5) are also provided with electrical connection surfaces to provide an electrical connection between the first (3) and the second module (5) to be placed on one another, and said at least two modules (3, 5) being joined together by placing the first (3) and the second module (5) at least partially on one another and by placing between the first (3) and the second module (5) a fastening layer, with which fastening of the first (3) and the second module (5) is provided. on each other. Method according to Claim 1, characterized in that said at least two modules (3, 5) are joined together by means of a thermoplastic film (10). Method according to claim 2, characterized in that at least one module (5) is substantially coated in its entirety with the thermoplastic film (10). > I • · Method according to claim 1, 2 or 3, characterized in that the modules (5) are of different sizes. · '· 35 Process according to claim 4, characterized in that the smaller module (5) is substantially coated in its entirety with the thermoplastic film (10). 11357C Process according to any of claims 2-5, characterized in that the thermoplastic film is cooled to join at least two modules (3, 5). 5 Process according to claim 1, characterized in that said at least two modules (3, 5) are joined together by means of an isotropic or anisotropic paste. 10 Method according to any of claims 1-7, characterized in that said electric oscillation circuit (L, C1, C2) comprises at least two capacitors (C1, C2) with two capacitor plates (6a, 7a; 6b, 7b), that one the capacitor plate (6a, 7a) of said at least two capacitors is formed in the first module (3) and the second capacitor plate (6b, 7b) is formed in the second module (5). Method according to claim 8, characterized in that the gap between the modules (3, 5) is left without any contact connection. 20 Method according to any of claims 1-9, characterized in that at least one contact connection is formed between the modules (3, 5). Method according to claim 10, characterized in that said at least one contact connection is formed by using for connecting the modules a thermoplastic film which is conductive essentially only in the direction of the thickness of the film. *: Ί Method according to any of claims 1-11, characterized in that a different substrate material than the second module (5) is used in the first module (3). > 1 · · · · · · Method according to any of claims 1-12, characterized in that the modules (3) are joined together substantially continuously. * » Product sensor (2) comprising a wiring circuit (L, C1, C2) and at least one fuse (F) for deactivating said electric vibration circuit (L, C1, C2), characterized in that the product sensor (L) 2) at least two modules (3, 5) comprise that the first module (3) is formed on a first substrate (1) which is an insulation, that on the first substrate (1) a first metallization layer is formed; and the first metallization layer is provided with a conduit pattern to provide at least one coil (L) for the electrical resonant circuit, and the second module (5) is formed on a second substrate (4) which is an insulation the second substrate (4) is formed a metallization layer, and the metallization layer is provided with at least one fuse (F), that the first (3) and the second module (5) are further provided with electrical connection surfaces to provide an electrical connection with Between the first (3) and the second module (5), which are placed on each other, and that said at least two modules (3, 5) are joined together by placing the first (3) and the second module (5) at least partially on each other and by placing between the first (3) and the second module (5) a fastening layer, which is arranged to secure the attachment of the first (3) and the second module (5) to each other. Product sensor (2) according to claim 14, characterized in that said at least two modules (3, 5) are joined together by means of a thermoplastic film (10). > 'Λ Product sensor (2) according to claim 15, characterized in that at least one module (5) is coated substantially in its entirety with the "thermoplastic film (10). Product sensor (2) according to claim 14, 15 or 16, characterized in that the modules (5) are of different sizes. : · 30 Product sensor (2) according to claim 17, characterized in that it *. the smaller module (5) is coated substantially in its entirety with the thermoplastic film (10). The product sensor (2) according to claim 14, characterized in that said at least two modules (3, 5) are joined together by means of an isotropic or anisotropic paste. 11357C Product sensor (2) according to claim 14, 15 or 19, characterized in that said electric oscillation circuit (L, C1, C2) comprises at least two capacitors (C1, C2) with two capacitor plates (6a, 7a; 6b, 7b). ), that one capacitor plate (6a, 7a) of said at least 5 capacitors is provided in the first module (3) and the second capacitor plate (6b, 7b) is arranged in the second module (5). Product sensor (2) according to claim 20, characterized in that the space between the modules (3, 5) is left without any contact connection. Product sensor (2) according to any of claims 14-21, characterized in that at least one contact connection is provided between the modules (3, 5). 15 Product sensor (2) according to claim 22, characterized in that said at least one contact connection is provided by using for connecting the modules a thermoplastic film which is electrically conductive essentially only in the direction of the thickness of the film. 20 Product sensor (2) according to any of claims 14-22, characterized in that a different substrate material than the second module (5) was used in the first module (3). «·« * »T · t