TW201316259A - Process for determining a code by means of capacities - Google Patents

Abstract

The invention relates to a method for recognising an item of information (20), comprising the steps a. provision of a layer structure (10) comprising i. a dielectric (50), ii. at least a first electrically conductive layer (30) and at least one further electrically conductive layer (60) separated by the dielectric (50), wherein the first conductive layer (30) comprises an electrically conductive polymer, wherein the first layer (30) comprises a cell (35, 35') with a surface resistance Z, wherein this cell (35, 35') is adjacent to a region (45, 45') with a surface resistance B, wherein the surface resistance Z is lower than the surface resistance B; b. electrical contacting of the first layer (30) over a period of time of less than 60 seconds, an electrical capacitance being determined; c. comparison of the electrical capacitance with a target value corresponding to the item of information (20).

Description

Procedure for determining the code by capacitance

The invention relates to the field of information recognition, in particular for codes on objects, in particular capacitive-based information recognition. For example, these methods can be used for security purposes, or for data acquisition of objects, to avoid counterfeiting of objects, or to make batch data of objects to be difficult to access by other methods.

The identification for security code or the method for data transfer is known from the art. Thus, for example, the application of radio frequency (RF) codes to the packaging of goods or merchandise for storage and for making batch data, shelf life data or other important materials available is known. This is for example described in EP 2006794 A1 for RFID systems.

Non-contact reading of the code as an information carrier on a package of valuable objects such as pharmaceuticals, foodstuffs and valuables is well known. WO 02/071345 A2 thus describes the introduction of electronic codes that can be read by a contactless method into the packaging of such valuable objects. However, the method proposed in the WO requires a relatively high difference in surface resistance to establish the code. Due to the high difference in surface resistance, the counterfeiting of the code becomes easy.

In general, these non-contact safety methods are easy to handle and can also be read on sensitive devices without risk of damage. However, due to the low resolution relationship, only relatively highly textured surface codes can be read using methods known in the art. Furthermore, high frequency The source of the interference may distort the reading. The measurement results of the non-contact capacitive measurement method depend very much on the distance between the sensor and the test object, which may cause distortion of the measurement result.

Accordingly, it is an object of the present invention to at least partially overcome at least one of the disadvantages of the prior art. In particular, the resolution of the improved code structure will be achieved. Furthermore, the accuracy of the measurement will be improved.

Furthermore, it is an object of the present invention to provide a value-for-money and secure coding system in which as much information as possible can be easily stored in a small space that cannot be, for example, contactless. Known methods are read. Furthermore, it should be possible to store this information as safely as possible to avoid counterfeiting.

Furthermore, it is an object of the present invention to provide an encoding system whose inspection under visible light is substantially unrecognizable and which also meets the criteria for high security. Therefore, the identification of the code by conventional methods should be made difficult, and thus the security against counterfeiting is improved.

Furthermore, it is an object of the present invention to provide an encoding system which is a thin layer and which is flexible, value-for-money and has a high density of information.

The contribution to at least one of the above objects is accomplished by the present invention having the features of the independent scope of the patent application. Advantageous further developments of the invention which may be implemented individually or in any desired combination are described in the dependent claims.

In a first feature, the invention relates to a method for identifying a capital The method of the present invention comprises the steps of: a. providing a layer structure comprising i. a dielectric, ii. at least one first conductive layer separated by the dielectric and at least one other a conductive layer, wherein the first conductive layer comprises a conductive polymer, preferably in each case according to the layer, to the extent of at least 10% by weight, particularly preferably at least 20% by weight To the extent that it is at least 30% by weight, wherein the first layer comprises a cell having a surface resistance Z, wherein the cell is adjacent to a region having a surface resistance B ( a region), wherein the surface resistance Z is lower than the surface resistance B; b. electrically contacting the first layer during a period of less than 60 seconds, a capacitance is determined; c. comparing the capacitance and a corresponding to the The target value of the information project.

In the context of the present invention, the method for identifying an information item can be configured for any embodiment of the information item. In an embodiment, the information item may be a code, preferably a security code, such as a security mark on a banknote, a medicament, a ticket or an item, or an information item of a quality in another embodiment. For example, it meets the requirements of the product or process, or a combination of the two.

This information can be generated from any type of configuration of the layer structure. because Thus, as a first configuration, the two-dimensional or three-dimensional structure of the cell can produce a spatial form feature of a certain information item. A second configuration can represent the position of at least two cells relative to each other. This can be achieved by a smaller or larger interval of the cells, with a larger interval being assigned to a first item and a smaller interval being assigned to another information item as a configuration. A third configuration can be achieved by varying the thickness of the dielectric. Thus, a first information item can be assigned a thickness and a further information item can be assigned a thickness different from the first thickness. Information can also be generated from a combination of two or more configurations. It is preferred that the combination of at least two of the first, second and third configurations obtains an information item.

The layer structure embodying the information item can be incorporated into an object or applied to the object. In the case of inclusion or application, it is preferred to be able to produce contact with sufficient safety and reliability. The object can also be part of the layer structure.

The layer structure or the joining of portions of the layer structure to the object is preferably achieved such that separation of the layer structure or portions of the layer structure can result in destruction of the information item.

The mechanical stability of the layer structure, especially the tension and flexural strength, can be achieved in a variety of ways. Thus, either of the two layers, or each of the dielectrics, can contribute to the mechanical stability. Furthermore, the dielectric, the other layer, or both can contribute to the mechanical stability. In the manufacture of the layer structure according to the invention, it is therefore preferred to provide a layer which contributes primarily to the mechanical stability or to provide the dielectric together with the other layer.

Furthermore, a layer structure will be understood to mean a unit that is established from at least one layer, preferably from several layers, and has a length and width that is at least two times greater than the thickness of the unit. For example, the unit may have a width or length in the range between 0.1 mm and 5 m, preferably in the range between 1 mm and 1 m, and particularly preferably in the range between 1.5 mm and 50 cm. . For example, the thickness of the unit may be in the range of 0.001 mm to 1 cm, preferably in the range of 0.005 mm to 0.5 cm, and particularly preferably in the range of 0.01 mm to 0.1 cm. . For example, the layer structure can be realized in the form of a hard film of one or more layers, or preferably a flexible and thus flexible or rollable film. Furthermore, the preferably flexible material preferably has an electromagnetic wave in the range from 20 to 100% for electromagnetic waves in the range of visible light (usually in the range from 400 to 700 nm). The permeability, preferably in the range between 50 and 99%, is particularly preferably in the range from 80 to 95%.

The layer structure includes a dielectric. The dielectric may be any material having a surface resistance that is higher than the surface resistance of the first conductive layer and the other conductive layer. For example, the dielectric may be an oxide such as ceramic or glass (preferably a metal oxide) or a polymer (preferably a polymer). However, the dielectric can also be a paper or card. Preferably, the dielectric is a polymer. Possible polymers are, for example, polyvinyl alcohol, polyvinylpyrrolidone, polyvinyl chloride, polyvinyl acetate, polyvinyl butyral, polyacrylate, polyacrylamide, polymethacrylate, polymethyl methacrylate Amine, polyacrylonitrile, styrene/acrylate, vinyl acetate/acrylate and ethylene/vinyl acetate copolymer, polybutadiene, polyisoprene, polystyrene, polyether, polyester, polycarbonate An ester, polyurethane, polyamine, polyimine, polyfluorene, melamine-formaldehyde resin, epoxy resin, polyoxyalkylene resin or cellulose, or a mixture of at least two of these polymers. Furthermore, feasible polymers are also those which are added by, for example, a melamine compound, a masking isocyanate or a functional decane (for example, 3-glycidoxypropyltrialkoxy decane, tetraethoxy decane, and tetraethylidene). A crosslinking agent of the oxoxane hydrolyzate, or a crosslinkable polymer such as a polyurethane, a polyacrylate, or a polyene, and a polymer produced by subsequent crosslinking. The polymer is preferably made of polyester, polyvinyl chloride (PVC), polyvinyl acetate (PVAc), polyethylene (PE), ABS, polystyrene (PS), polycarbonate (PC), Polymethyl methacrylate (PMMA), polyethylene glycol (PEG), or a group of at least two of these polymers is selected. Preferably, the dielectric is also transparent. In general, the dielectric, which is preferably constructed as a layer, can have a thickness to cause electrical separation of the first conductive layer and the other conductive layer. Preferably, the thickness of the dielectric is in the range from 1 nm to 1 mm, preferably in the range from 50 nm to 500 μm, and particularly preferably in the range from 100 nm to 200 μm, and further It is preferably in the range from 200 nm to 100 μm. Furthermore, the dielectric acts as an insulator between the first conductive layer and the other conductive layer. The surface resistance of the dielectric utilized in accordance with the present invention is preferably in the range of greater than 10 ¹⁰ ohms/square, preferably greater than 10 ¹¹ ohms/square, and more preferably greater than 10 ^In the range of ¹² ohms/square. Furthermore, in an embodiment in accordance with the invention, it is preferred that the dielectric of the layer structure be provided with this. For this reason, it is preferred that the dielectric has high strength or mechanical stability or both. This is achieved, for example, by a dielectric having a polymer film. In addition to the dielectric, there may be one or more additional functional layers between the first conductive layer and the other conductive layer, such as a separation layer or a filter. These functional layers may be present on one or both sides of the dielectric. Such a functional layer can be in any plane of the layer structure.

The layer structure further has at least one first conductive layer and at least one other conductive layer electrically separated by the dielectric. The first conductive layer comprises at least one electrically conductive polymer. Furthermore, the first conductive layer may comprise an adhesive. Preferably, the first conductive layer comprises a polymeric organic binder. Particularly preferred polymeric organic binders are, for example, polyvinyl alcohol, polyvinylpyrrolidone, polyvinyl chloride, polyvinyl acetate, polyvinyl butyral, polyacrylate, polyacrylamide, polymethacrylate, poly Indole methacrylate, polyacrylonitrile, styrene/acrylate, vinyl acetate/acrylate and ethylene/vinyl acetate copolymer, polybutadiene, polyisoprene, polystyrene, polyether, poly Ester, polycarbonate, polyurethane, polyamide, polyimine, polyfluorene, melamine-formaldehyde resin, epoxy resin, polyoxyalkylene resin or cellulose. Further, preferred polymerizable organic binders are also those which are added, for example, by a melamine compound, a masking isocyanate or a functional decane (for example, 3-glycidoxypropyltrialkoxydecane, tetraethoxy). A crosslinking agent of decane and a tetraethoxy decane hydrolyzate or a crosslinkable polymer such as a polyurethane, a polyacrylate, or a polyene, and a polymerized organic binder prepared by subsequent crosslinking. Such a crosslinked product suitable as a polymeric binder can also be selected, for example, by the added crosslinking agent. The reaction of the polymerized anion contained in the first conductive layer is formed in the ground.

Generally, the length and width of the first conductive layer and the other conductive layer are dominated by the size of the layer structure, or correspond to the size of the layer structure, or less than these dimensions. The first conductive layer and at least one of the at least one other conductive layer may have, for example, a width or length in the range of between 0.1 mm and 5 m, preferably between 1 mm and 1 m. Among them, particularly preferred is in the range between 1.5 mm and 50 cm. The thickness of the first layer and the at least one other conductive layer may be, for example, in the range from 1 nm to 100 μm, preferably in the range from 5 nm to 10 μm, particularly preferably from 10 nm to 5 μm, which is very good. It is in the range from 15 nm to 1 μm. The first conductive layer comprises a cell having a surface resistance Z, wherein the cell line is adjacent to a region having a surface resistance B, wherein the surface resistance Z is lower than the surface resistance B. Preferably, according to the present invention, Z is in the range of from 1 to 10 ⁷ ohms/square, preferably in the range of from 10 to 10 ⁶ ohms/square, and particularly preferably from 100 to In the range of 10 ⁵ ohms/square.

Further, the cell having a surface resistance Z is preferably in the same plane as the region having a surface resistance B. Preferably, the cell and the region are the constituents of the first conductive layer.

Therefore, it is further preferred according to the invention that the electrically conductive layer is produced from the same application step. Here, it is preferred that the conductive layer is applied in a first step, and in another step, the surface resistance of the layer applied in this manner is increased in a portion of the layer to form These districts.

The first conductive layer can have a plurality of cells or regions. In this context, the cell can be adjacent to more than one zone. Preferably, the cell and the extension of the region in one dimension form at least a portion of the first conductive layer. Therefore, the cell or the region may have an extension in this dimension in the range from 1 μm to 50 cm, preferably in the range from 10 μm to 5 cm, and particularly preferably from 10 μm to 1 cm. In the scope.

If there are more than one cell and one zone in the first conductive layer, then these cells and zones can be configured in the most diverse manner. In general, the cells and regions can have any shape. For example, the cells and regions may have the following shapes in the plane of the layer structure: for example, triangular, quadrangular, pentagonal or hexagonal angular or polygonal, circular or elliptical. These shapes can be configured regularly or irregularly with respect to each other. A uniform two-dimensional or multi-dimensional pattern can thus produce, for example, a one-sided configuration or a diamond-like pattern. Alternatively or additionally, an irregular configuration of the cells and regions can be achieved in the layer structure.

The difference in surface resistance Z and B between the cell and the region can be achieved by various methods. For example, the cell and the zone can be made of the same material as, for example, a conductive polymer. In the at least one region, a portion of the surface resistance can be reduced by modifying the chemical or structural form of the layer, such as by irradiation, chemical treatment such as etching, mechanical treatment such as scratching. Or, heating or a combination of at least two of these means, as will be further explained below. Alternatively, the cell and the region may also be made of different materials having surface resistances Z and B different from each other, and in each case having a lower surface resistance than the dielectric.

The at least one other electrically conductive layer may likewise comprise a conductive polymer. Further or alternatively, the at least one further electrically conductive layer may comprise another electrically conductive material such as a metal, preferably selected from the group consisting of copper, gold, silver, aluminum, chromium or platinum. At least one of the at least one other electrically conductive layer may alternatively or additionally comprise another electrically conductive material, such as carbon or graphite. Preferably, the at least one other layer comprises aluminum, or a conductive polymer, or a combination of the two. The first conductive layer is preferably spatially separated from the at least one other conductive layer such that no electrical contact exists between the layers. Preferably, the at least one other electrically conductive layer has a surface resistance of less than 10 ⁶ ohms/square, more preferably less than 10 ⁵ ohms/square, and most preferably less than 10 ⁴ ohms/square. The surface resistance of the at least one other conductive layer is preferably lower than the surface resistance of the cells of the first conductive layer.

The configuration of the at least one cell relative to the at least one zone can be achieved in a variety of ways. Therefore, it is preferred that the first conductive layer be applied by a coating process. Possible coating processes are, in particular, printing, dipping, baking, spraying, casting or laminating or a combination of at least two of these processes. For example, a preferred printing process is gravure printing, letterpress printing, ink jet or screen printing, or a combination of at least two of these printing processes. These printing processes include printing processes that are often employed in the electrical industry and often used as lithographic or flexographic printing.

Preferably, the coating can tolerate a resolution of less than 5 mm, preferably less than 1 mm, and particularly preferably less than 100 μm. Therefore, for example, a cell can be obtained by the printing, wherein a region adjacent to a polymer having no conductivity is A less conductive polymer layer is applied to the surface of the dielectric. In other coating processes such as dipping, baking, spraying or casting, a layer of electrically conductive polymer is first produced. In a subsequent step, often referred to as structuring, the surface resistance is locally increased by means of the means already described above to facilitate obtaining a cell and a region by this means. This structuring is preferably carried out by the use of a mask.

The spatial form and arrangement of the at least one cell and the at least one region, for example, height, width, length, the thickness of the dielectric, or the position of at least two cells or regions relative to each other, or the means Based on a combination of at least two, one code can be conceived. The size or configuration of each cell or zone or both is suitable for embodying information corresponding to a code in the layer structure. Depending on the extension of the cells and regions within the first conductive layer, a different number of information units can be stored in the first conductive layer and determined by the method according to the present invention. The area of the cells in the plane of the layer structure may be in the range from 0.01 mm ² to 10 cm ² , preferably in the range from 0.1 mm ² to 0.5 cm ² , and particularly preferably in the range In the range of 0.5 mm ² to 0.1 cm ² . Another step of the method according to the invention comprises electrically contacting the first layer during a period of less than 60 seconds, preferably less than 10 seconds, and more preferably less than 1 second, a capacitance is judged. Preferably, the contacting is performed by contacting at least the first conductive layer. Such contact is preferably separable, such as by passing a contact element over a portion of the first conductive layer. In this context, it is preferred that the contact element has dimensions such that it can distinguish between a cell according to the invention and a zone according to the invention. This is preferably achieved by the fact that the contact element has an area of contact that is smaller than the smallest cell or the smallest of the areas, whichever is smaller.

This contact can be achieved directly or indirectly. For example, if the cell or zone is directly accessible for contact, then direct contact can be achieved. An indirect contact indicates that the contact is indirectly produced. Contacting may be achieved indirectly via at least one intermediate layer disposed between the contact region and the first conductive layer. When the intermediate layer is selected, it is preferred that the system has at least a low surface resistance such that contact can be generated between the first conductive layer and the contact region. Preferably, a layer of a mechanical protective layer as the first conductive layer is employed as the intermediate layer. In another embodiment, the degree of electrical insulation of the intermediate layer is a weakening of the intermediate layer necessary for contact, preferably piercing.

The contact of the first layer is produced, for example, via a device, such as a measuring device, which may, for example, have at least one contact element that can be supplied with current via a voltage generator. The contact element can have, for example, a wire, a pin, a ball or a carbon brush, preferably a sphere. The contact element can have any shape so that sufficient contact with the layer structure can be achieved for the determination of the capacitance of the layer structure. Thus, the contact element can be point, circular or flat in shape, for example, in the form of a pin, a tip of a needle or a crown contact, a sphere or a plate. The contact element can be made of any material suitable for sufficiently conducting current so as to be able to determine the capacitance of the layer structure. Preferably, the material of the contact element can be made of a metal or carbon or a combination of the two. The metal may be selected from the group consisting of copper, gold, silver, aluminum, chromium or platinum and at least two of these metals. The size of the contact should match the size of the cells and regions of the first conductive layer. Therefore, the contact should have a resolution that is less than the space of the smallest extension of another cell or another zone. Preferably, the extension of the contact is in the range between 1 μm ² and 10 cm ² , preferably in the range from 1 μm ² to 1 cm ² , preferably from 1 μm ² to 0.5 cm ² . In the range, particularly preferred is in the range from 1.5 μm ² to 0.1 cm ² . In an embodiment of the invention, one of the first contact elements and one of the other contact elements having different extensions from one another are employed. According to the invention, the further contact element can also be in the form of a large area, for example in the form of another electrically conductive layer which can be separated. Therefore, it is preferred that the first contact element has the extension described above. The further contact element preferably has a larger extent than the first contact element, preferably in the range from the region of the cell to the region of the layer structure.

For example, the capacitance of the cells and regions can be measured using a commercially available LCR measuring device or a universal meter.

Another step of the method according to the invention comprises comparing the capacitance with a target value corresponding to the code. This comparison can be manual, that is, by reading a measurement and comparing it to a known value, for example, in a table, or by electronically using the measurement and a storage. The content, a reference, or a comparison of the database is implemented. The database in this context may be, for example, a component for the connection of the layer structure, or may be contacted to the Internet, for example, via a contactless connection to the Internet or via a cable. An electronically linked, separate database.

In a preferred embodiment of the method, the surface resistance of the first conductive layer and the surface resistance of the other conductive layer differ by a maximum of 50,000 ohms/square.

In another preferred embodiment of the method, the first conductive layer has a higher surface resistance than the other conductive layer. In a preferred embodiment, the cell and the zone comprise the electrically conductive polymer. The cell and the zone may comprise different electrically conductive polymers, or at least partially identical electrically conductive polymers. The difference in surface resistance between the cell and the region can be achieved by different concentrations of conductive polymer or conductive polymers of different compositions. Another possibility for providing cells and regions having different surface resistances in the first conductive layer is to use a uniform conductive polymer whose surface resistance is modified in at least one region (preferably Increase), for example by irradiation (preferably in the UV or IR range), chemical treatment such as etching, mechanical treatment like scratching, or heating (preferably reaching from 150 to 350) The temperature in the range of °C), or a combination of at least two of these methods, is treated as a surface resistance. An area including at least one cell and at least one region may be disposed in the layer structure in such a manner that cells or regions of one region or both are different in surface resistance from another region. Cell or zone or both. The difference in capacitance of different regions of the layer structure can act to store a particular information item in the layer structure in a code. The size of the dielectric also has considerable influence on the difference in capacitance of the various layers. Furthermore, it is preferred that the surface resistance B is greater than the surface resistance of the dielectric. Preferably, the surface resistance B of the region of the conductive layer is in the range of from 10 ⁵ to 10 ¹⁰ ohms/square, preferably from 10 ⁶ to 10 ⁹ ohms/square, particularly preferred. It is in the range from 10 ⁵ to 10 ⁸ ohms/square. In another preferred embodiment of the method, the at least one other electrically conductive layer has a conductive polymer. The same conductive polymer or other conductive polymer as in the first conductive layer can be utilized. Any polymer having a surface resistance lower than the dielectric can be utilized as the conductive polymer. The conductive polymer of the first or the at least one other conductive layer may comprise a polymer selected from the group consisting of polypyrrole, polyaniline, polythiophene, polyacetylene, polyisothianaphthene, and polyparaphenylene and derivatives thereof. A group of electrically conductive polymers of a mixture of at least two of the materials.

Furthermore, it is preferred that the conductive polymer is poly(3,4-ethylenedioxythiophene), also known as PEDOT, and particularly preferably poly(3,4-ethylenedioxythiophene)-polystyrene. acid, also known as PEDOT / PSS, for example, under the trade name Clevios ^® P are commercially available. The electrically conductive polymer may be the sole material of the first or at least one other electrically conductive layer, or one of the electrically conductive layers may be constructed with another material. As already mentioned, another material that is feasible is a binder, or other polymer, or other electrically conductive material, such as a metal of aluminum, copper, gold, silver or platinum.

In a preferred embodiment, at least one of the conductive layers is transparent. In particular, high transparency is desirable if the layer structure comprising the code is intended to be attached to an object or to include an object that is not visually covered by the layer structure. Furthermore, high optical permeability can be advantageous if optical coding is achieved in addition to electronic codes. The permeability of the layer structure can also act to achieve an inconspicuous encoding of an object. Therefore, a layer structure which is transparent to the human eye is preferable. Especially if the layer structure is When one of the wavelengths of light having a wavelength of from 400 to 700 nm has a permeability of at least 30%, it is the optical permeability mentioned in accordance with the present invention. Preferably, the layer structure is transparent to wavelengths in the wavelength range of at least between 500 and 600 nm, more preferably between 520 and 580 nm, and most preferably between 540 and 560 nm. In the range of wavelengths. Preferably, the permeability in these ranges is greater than 30%, preferably greater than 50%, and particularly preferably greater than 80%. This permeability is often judged at 550 nm.

Furthermore, it is preferred that the first conductive layer and the dielectric system are made of a flexible material. Furthermore, it is considered to be particularly preferred that at least one layer of the at least one other electrically conductive layer is made of a flexible material. To this end, a suitable material for the dielectric is, for example, a polymer, preferably in the form of a layer or film, thin glass or cellulose.

In a preferred embodiment of the method, Z/B is <10. For example, the ratio can be achieved by the cell line being uniquely composed of a conductive polymer, and the region is completely free of conductive polymers or only partially comprising conductive polymers. This ratio can be further established by surface resistance treatment on a conductive polymer layer as described above.

It is further preferred that the cell and the zone are visually substantially indistinguishable. The substance in this case is difficult to distinguish, and in the case where the wavelength is in the range of 300 to 800 nm per wavelength, the difference in permeability between the cell and the region is not more than 20%, preferably Not more than 15%, especially not more than 10%. Because of this, the information item cannot be identified by the naked eye.

In an embodiment in accordance with the invention, the color separation ΔE _cell,region is at most 4.5, particularly preferably at most 3.0, and most preferably at most 1.5. The color separation ΔE _cell,region is calculated as follows:

In this context, L*cell, a*cell, and b*cell are the L, a, and b values of the L*a*b* color space of the cell, respectively, and L*region, a*region, and b*region are respectively It is the L, a, and b values of the L*a*b* color space in the area.

In a preferred embodiment, the capacitance between the first conductive layer and the other conductive layer is determined. To this end, the further electrically conductive layer can be in direct contact. The contact can also be achieved by a contact through the dielectric to at least one of the first conductive layers, which is often referred to as a through contact.

Alternatively, the capacitance between the cell and the zone can be determined. In order to determine the capacitance between the two points of the layer structure, at least two points of the layer structure are contacted in each case by means of an electrode in the form of a contact element.

In another preferred embodiment, the capacitance between the cell and the zone is determined. In an embodiment in accordance with the invention, it is preferred to measure capacitance not only between the cell and the region directly adjacent to the cell. Rather, the capacitance between one cell and at least one of the adjacent cells is also included in this embodiment.

Preferably, the layer structure may include a first cell and at least one other cell, and a capacitance between the first cell and the at least one other cell is determined. As already mentioned, the capacitive pattern that can be utilized for encoding can be generated by a targeted configuration in which the various cells are distinguished by different ones. Thus, the various cells in the first conductive layer can have different capacitances.

In an embodiment in accordance with the invention, it is preferred that the capacitance between one of the cells on one side and the cell on the other side is determined. In another embodiment in accordance with the invention, it is preferred that the capacitance between the cells of at least two groups is determined. The group of cells is preferably formed by connecting two or more cells in parallel. In each case, a plurality of cells can be simultaneously contacted by a contact element.

In a preferred embodiment, the capacitance between the first cell and the region, or the capacitance between the at least one other cell and the region is determined. The capacitance of several cells and regions can also be judged continuously or simultaneously. Preferably, the determination of the capacitance between the first cell and the region is performed prior to the determination of the capacitance of the at least one other cell and the region.

In an embodiment of the method according to the invention, it is further preferred that the cells are disposed in the outer region of the layer structure, typically in the surface, and thus accessible from the outside. In order to be able to achieve the highest possible read speed by good contact, it is advantageous if the cells are in a row in the outer region of the layer structure. Therefore, they are easily accessible to the measuring device. To protect the first conductive layer, another layer can be applied over the layer. Preferably, the layer is also electrically conductive so that the capacitance can be measured through the additional layer. This additional layer may, for example, be an antistatic layer that prevents the layer structure from becoming charged during the measurement. The additional layer, which typically acts as a protective layer, may further preferably be an insulating layer that is weakened or even breached for contacting the first conductive layer. The additional layer preferably comprises a polymer. Preferred polymers for the additional layer are associated with the binder and the polypolymers mentioned in the dielectric Compound.

As already described in the above paragraphs, in another method embodiment in accordance with the invention, a protective layer is applied over the first conductive layer. This protective layer can be one of the layers, also referred to as another layer. The protective layer can be applied directly or indirectly over the first conductive layer. Preferably, the protective layer is applied directly over the first conductive layer. The protective layer preferably comprises a conductive polymer. The conductive polymer of the protective layer preferably comprises a conductive polymer, especially selected from the group consisting of polypyrrole, polyaniline, polythiophene, polyacetylene, polyisothianaphthene, and polyparaphenylene and derivatives thereof. A group of mixtures of at least two of the polymers. It is further preferred that the electrically conductive polymer is poly(3,4-ethylenedioxythiophene), also known as PEDOT. It may further be preferred that the electrically conductive polymer comprises a polymeric anion, preferably poly(styrenesulfonic acid), also known as PSS. Thus, particularly preferred is poly (3,4-ethylenedioxythiophene) poly (styrenesulfonate) also called PEDOT / PSS, for example, under the trade name Clevios ^® P are commercially available.

The protective layer preferably comprises a non-conductive polymer which is preferably crosslinked. Possible polymers are, for example, polyvinyl alcohol, polyvinylpyrrolidone, polyvinyl chloride, polyvinyl acetate, polyvinyl butyral, polyacrylate, polyacrylamide, polymethacrylate, polymethyl methacrylate. , polyacrylonitrile, styrene/acrylate, vinyl acetate/acrylate and ethylene/vinyl acetate copolymer, polybutadiene, polyisoprene, polystyrene, polyether, polyester, polycarbonate , polyurethane, polyamide, polyimine, polyfluorene, melamine-formaldehyde resin, epoxy resin, polyoxyalkylene resin or cellulose or a mixture of at least two of these polymers. Furthermore, feasible The polymers are also those which are hydrolyzed by the addition of, for example, a melamine compound, a masking isocyanate or a functional decane (for example, 3-glycidoxypropyl trialkoxy decane, tetraethoxy decane, and tetraethoxy decane). a polymer made by a crosslinking agent. Preferred crosslinkable polymers are polyurethanes, polyacrylates or polyolefins. The polymer is preferably made of polyester, polyvinyl chloride (PVC), polyvinyl acetate (PVAc), polyethylene (PE), ABS, polystyrene (PS), polycarbonate (PC), Polymethyl methacrylate (PMMA), polyethylene glycol (PEG), or a group of at least two of these polymers is selected. The non-conductive polymer is preferably radiation cured, such as a lacquer.

Preferably, the protective layer comprises the conductive polymer and the non-conductive polymer in a ratio of 1:1.5 to 1:10, particularly preferably in a ratio of from 1:1.5 to 1:5.

In a preferred method embodiment, the surface resistance of the protective layer is in the range of from 10 ⁵ to 10 ¹⁰ ohms/square, and particularly preferably in the range of from 10 ⁶ to 10 ⁹ ohms/square. It is preferably in the range of from 10 ⁷ to 10 ⁹ ohms/square.

In a preferred method embodiment, the surface resistance of the protective layer is higher than the surface resistance of the first conductive layer and the other conductive layer, and lower than the surface resistance of the dielectric. By selecting the surface resistance in the region between the conductive layer and the surface resistance of the dielectric, it can be achieved that, on the one hand, no crosstalk occurs between different cells, but on the other hand This layer structure does not become electrically overloaded.

In an embodiment of the method according to the present invention, it is further preferred that The width of these cells is in the range from 0.01 mm to 1 cm, particularly preferably in the range from 0.1 mm to 0.5 cm, and very preferably in the range from 0.1 mm to 0.1 cm. It is also preferred that the zones are in these width ranges.

In an embodiment of the method according to the present invention, it is preferred that the first conductive layer comprises at least two cells that differ in length. If the height and width remain the same, the difference in length results in a proportional difference in the capacitance value. The difference in capacitance can also be achieved by varying the width while fixing the length and height of the cells. Furthermore, it is preferred that the cell lines are oriented parallel to each other. Preferably, the difference in length of at least two cells is a reference to the length of the smallest cell, a factor in the range from 1.1 to 100, particularly preferably in the range from 1.1 to 50, and very good. It is in the range from 1.1 to 10.

In an embodiment of the method according to the invention, the dielectric and the first electrically conductive layer are then preferably bonded to each other. This combination can be achieved in any way that avoids the separation of the two layers by gravity alone. The dielectric can thus be bonded to the first conductive layer by an adhesion promoter such as an adhesive. The dielectric can also be melted onto the first conductive layer, or vice versa.

It is further preferred that the further electrically conductive layer is separable from the layer structure. Preferably, the separation can be achieved by manual lifting. Preferably, the other electrically conductive layer is not bonded to another layer of the layer structure by gluing or equivalent bonding.

Further details and features of the present invention appear in the following preferred embodiments. A description of the examples of the examples, especially in conjunction with the scope of the patent application. These specific features can be implemented here by themselves or in combination with one another. The invention is not limited to the examples of the embodiments. Examples of such embodiments are shown in the drawings in the drawings. In this context, the same element symbols in the individual figures refer to the same, or functionally identical, or elements whose functions correspond to each other.

testing method

Judgment of the surface resistance

In order to judge the surface resistance, a 2.5 cm long Ag electrode was vapor-deposited via a shadow mask, making resistance measurement in each of the regions A and B possible. The surface resistance was judged by contacting the Ag electrode and a potentiometer (Keithly 614). This determination is carried out by means of a so-called "four-point probe" measurement as described, for example, in US 6,943,571 B1. In general, ohms/squares are used as the unit of the surface resistance.

The color values L, a and b and the judgment of transmission

The procedure for measuring the transmission spectrum of a coated PET film is in accordance with ASTM 308-94a. To this end, a two-channel spectrometer from the Perkin Elmer model Lambda 900 was used. The device is equipped with a 15 cm photometer ball. The normal operation of the spectrometer is ensured and recorded by periodically checking the wavelength calibration and linearity of the detector according to the manufacturer's recommendations.

For this measurement of transmission, the film to be measured is fixed in front of the entrance opening of the photometer ball by means of a holder, whereby the measuring beam penetrates the film without shading. The film is visually uniform in the region of the penetrating measurement beam. The film is oriented with the coated side facing the ball. The transmission spectrum is recorded in the wavelength range of 320-780 nm with a wavelength increment of 5 nm. In this context, there are no samples in the reference beam path, so the measurement is done for air.

In order to evaluate the color of the transmission spectrum, the "WinCol-Version 1.2" soft system provided by the manufacturer of the device is used. In this context, the CIE tristimulus values (standard color values) X, Y and Z of the transmission spectrum in the wavelength range of 380-780 nm are calculated according to ASTM 308-94a and DIN 5033. According to ASTM 308-94a and DIN 5033, the standard color value components x and y and the CIELAB coordinates L*, a* and b* are calculated from the color values of the standard.

1 is a schematic illustration showing the fabrication of a layer of structure 10 into which an information item 20 is introduced by means of step 110. In order to create the layer structure 10, a further conductive layer 60 is first provided. To this end, a conductive polymer in the form of a water-containing PEDOT/PSS dispersion (Clevios FET, Heraeus) was knife coated onto a 12 μm wet film doctor blade (Erichsen). The substrate 40 was baked and dried at 130 ° C for 5 minutes. In the example shown here, this layer 60 is applied to a substrate 40 comprised of a PET film. The fabrication includes a thin layer of dielectric 50 applied to the other conductive layer 60 as a first step 80. For example, this application can be carried out by simple coating, spraying or printing. In this case, the polymer was applied by a 18 μm wet film doctor blade (Erichsen). A photoresist (mr-UVL6000, Micro Resist Technology) is used herein as the polymer. The photoresist was cured by UV radiation (Hg vapor lamp, wavelength 365 nm, 500 mJ/cm ² ). In a second step 90, a first conductive layer 30 in the form of a PEDOT/PSS dispersion (Clevios F 010, Black Layers) is applied using a 6 μm wet film doctor blade (Erichsen) and It was dried at 130 ° C for 5 minutes. In a third step 100, an additional layer 70 in the form of an antistatic PEDT/PSS protective layer 70 (Clevios F 141D) is blade coated onto the first conductive layer using a 4 μm wet film doctor blade (Erichsen). 30, and dried at 130 ° C for 5 minutes. In a fourth step 110, a structure having the form of a code 20 is by UV radiation (Hg vapor lamp, wavelength 253.6 nm, UV-C output 15 mW/cm ² , exposure time 1,000 s) and a reticle. The layer structure 10 is incorporated in the side of the protective layer 70. The structure has at least one cell 35, 35' and at least one zone 45, 45' having different surface resistances Z and B due to the illumination 120 of the first conductive layer 30 in the fourth step 110.

2a illustrates a layer structure (10) composed of the first conductive layer 30, a dielectric 50, and a further conductive layer 60. In this example, the dielectric 50 is formed by a PET film. The first conductive layer 30 comprises a conductive polymer. The dielectric 50 is placed on the other conductive layer 60, which in this example has the form of a metal plate. The dimensions of the dielectric 50 are selected here such that they do not protrude beyond the other conductive layer 60. In this example, the selected other conductive layer 60 is It is longer and wider than the dielectric 50. Of course, this layer structure 10 can include other layers. The first conductive layer 30 includes a plurality of cells 35, 35' and a plurality of regions 45, 45'. The cells 35, 35' and the regions 45, 45' may have different surface resistances. The cells 35, 35' each have a surface resistance lower than the regions 45, 45'. In order to measure various capacitances at different points of the layer structure 10, in this example, the second conductive layer 60 acts as one of the opposite poles of a particular point to be measured on the first conductive layer 30. This is carried out by means of a capacitance measuring device 130 which is guided little by little over the surface of the first electrically conductive layer 30. The capacitance meter 130 thereby continuously contacts various positions of the conductive layer 30. This is schematically indicated once by a continuous arrow starting from the measuring device 130 connected to the cells 35, 35', which symbolizes a first measurement 131. The measuring head of the measuring device 130 then migrates to the next position indicated by the dashed line starting from the capacitance meter 130 and performs a second measurement 132. The capacitance of a portion or the entire surface of the layer structure 10 can be measured in this manner. The local capacitance value determined in this way can then be compared to a known capacitance threshold and thus provide an information item, such as an authentication.

Figure 2b is a layer 10 of structure shown in Figure 2a, but with the difference that the other conductive layer 60 is not provided by a metal plate, but by another electrically conductive polymer 60'. As already mentioned, this may be the same polymer as the first conductive layer 30 or a polymer different therefrom. In this case, they are the same polymer. This configuration has the advantage that the second conductive layer 60 is firmly bonded to the remainder of the layer structure 10 and thus unlikely to occur due to the air between the dielectric 50 and the other conductive layer 60. The measurement caused by the gap is not correct. The measurement system is continuously performed, initially at the first measurement 131, then at the second measurement 132, at the third measurement 133, at the fourth measurement 134, and finally at the fifth measurement 135. These data are further processed by means of a configuration as shown in FIG.

3 shows a measurement structure having the same layer structure 10 as that of FIG. 2a or 2b, but the measurement device 130 is not attached between the other conductive layer 60, 60' and the first conductive layer 30, Rather, the capacitance between the various cells 35, 35' and the various zones 45, 45' is determined.

For the measurements as shown in Figures 2a, 2b and 3, a measuring device is sufficient. In the above measurement, an LCR meter (Agilent 4284A) was employed as the capacitance measuring device, and gold-plated contact pins were used for the contact. The combination of the measurements of Figures 2a or 2b and the measurements of Figure 3 is shown in Figure 4a. Thus, two measurement systems between different cells 35, 35' and regions 45, 45', and between the first conductive layer 30 and the other conductive layer 60 are practiced herein. In order to be able to perform such measurements in parallel, two measuring devices are required in this example, otherwise the measurements must be performed in sequence. The advantage of the double judgment of the capacitor is the reading of the higher correctness of the code information. Furthermore, it is easier to determine if the layer structure has been damaged, destroyed or modified.

Another measurement structure for layer structure 10 similar to that of Figure 2a is shown in Figure 4b, wherein the layer structure 10 includes a protective layer 70. The pattern of this structure 10 is shown in Figure 6c in a top plan view. To achieve the layer structure 10 of Figure 4b, a foil layer of polyethylene terephthalate (PET) (Melinex 505) is used as the dielectric 50. Above the dielectric 50, the cells 35, 35' are created in a parallel strip pattern by screen printing using an ESC Atma AT 80 P from ESC Corporation. As the plurality of cells 35, 35 'of conductive material is used, the dispersion of Clevios ^TM S V3-based commercially available from a black Laye Ust Precious Metals used as the material of screen printing. The foil layer with the printed pattern was then heated at 130 ° C for 15 minutes in a hot air oven of Heraeus. The strip pattern of this layer structure 10 consists of eight strips, namely eight cells 35, 35', each strip having an adjacent strip length having a distance of 2 mm. A protective layer 70 is applied to the top end of the layer structure 10. To achieve this protection layer 70, dispersion-based Clevios ^TM CPP 103D of an aqueous 6μm wet film using a wire - long (available from RK Print-Coat British Equipment Corporation) is the line - coated strip The patterned PET foil layer was applied and dried at 130 ° C for 5 minutes. The protective layer 70 covers the cells 35, 35' and the entire surface of the dielectric 50 on this side of the layer structure 10. In order to perform measurement using the capacitance measuring device 130, a PET foil layer as a dielectric 50 is placed on an Al plate 60 on the opposite side of the printed pattern. The metal plate 60 is brought through the device 130 to directly or indirectly contact the different cells 35, 35' and the regions 45, 45' below the protective layer 70. In this manner, fifteen measurement systems from the first measurement 131 to the fifteenth measurement 145 are continuously established.

A measurement structure having a layer structure 10 similar to that of Figures 2 through 4a is shown in Figure 5, but only the structuring of the first conductive layer 30 is shown in plan view (as viewed from above). The cells 35, 35' were printed from a PEDT:PSS dispersion (Clevios P JET 700, Heraeus) by inkjet (Dimatix 2831 inkjet printer) to a 300 nm thick SiO _{2 .} On dielectric 50, it is applied as a further conductive layer 60 on a doped Si wafer and then dried at 120 °C. In each case, the capacitances are continuously between the cell 35 and one of the cells 35', from the position 1 indicated by the component symbols 150, 160, 170, 180 and 190 in the figure. 5. Measured by an LCR meter (Agilent 4284A). Gold-plated contact pins are used for this contact. The cell 35 is maintained at a distance from the other cell 35' and the regions 45 and 45' by a gap region 220. This has the effect of electrically insulating the cell 35 from the remaining cells 35' and regions 45, 45'. The capacitances calculated and determined for these various locations are shown in Table 1. A PEDOT/PSS polymer is used as the first conductive layer 30. In this way, it is possible to store the data in a 100 μm*1 cm size code having 50 bits.

As can be seen from the table and the figure, the capacitance determined is slightly higher than those determined by calculation. This applies to all positions 1 to 5 having the component symbols 150, 160, 170, 180, 190. This is in the meter The idealized assumptions and the non-optimal processes of the various layers. Since the capacitors can be judged after manufacture, the use of the code does not actually have an effect.

Figure 6a shows one possibility for providing a general information pattern 15 in a first conductive layer 30. It has the same elements as the cells 35 and cells 35' separated by the gap region 220. Thus, the cells 35' are separated from one another by zones 45 and 45'.

The general information pattern 15 from Fig. 6a can be modified by processing with UV light to obtain a particular information pattern 15 as shown in Fig. 6b. This is especially preferred if the end user wants to generate the information item 20 in a relatively simple manner. The specific information pattern 15 is not yet shown in Fig. 6a, and Fig. 6b shows the processing of the general information pattern 15 by UV illumination using a point of a UV laser. Such information 20 can be utilized in various ways as a component of the layer structure 10. It can therefore be used as an information carrier for a package of medicines or as a security feature for banknotes or other valuable objects.

As shown in Figure 6c, another way of configuring an information item 20 is in the form of a parallel strip pattern (like a code). In this pattern, eight cells 35, 35' in the form of strips of eight different lengths are arranged at a distance of 2 mm from each other, wherein the lengths of the strips are from the first strip to the last one. The strips, i.e., the orientation as shown in Figure 6c, are continuously increased from left to right. The smallest cell 35 has a length of 5 mm, followed by a cell 35' of 9 mm, followed by a cell 35' of 12 mm, followed by a cell 35' of 16 mm, followed by a cell 35' of 21 mm, followed by a cell 35' of 26 mm, followed by Is 32mm The cell 35' and finally the 39mm cell 35'. The cells 35, 35' are symmetrically disposed relative to a hypothetical horizontal line 250 extending through the middle of the layer structure 10. The space between the cells 35, 35' is also the zone 45, 45'.

The results of the structure shown in Figure 6c by measurements 131 through 145 of the capacitance measuring device 130 as configured in Figure 4b are shown in Figure 6d. Here, the first capacitance to the fifteenth measurement 145 are shown as relative values on the y-axis 240, and the x-axis 230 reflects the capacitance when the layer structure 10 of FIG. 6c is scanned from left to right. The position of the measuring device 130. The measurement 131 shown in Figure 4b of the smallest cell 35 of Figure 6c has a relative value of capacitance of about one. The largest cell 35' on the right hand side of the layer structure 10 of Figure 4b is measured by the measurement 145 and has a relative value of capacitance of about 8 in the graph of Figure 6d. Therefore, the value of the measurement 145 is 8 times the capacitance value of the measurement 131. This is directly related to the length ratio of the smallest strip 5 mm and the largest strip 39 mm, which has a length eight times that of an almost minimum strip.

Therefore, it is conceivable to apply the information item 20 in the form of the layer structure 10 as shown in Fig. 1 directly to the object 200 to be marked. This type of application to an object 200 is shown in Figure 7a. Another form of product designation can also be achieved by means of a label 210 comprising a layer structure 10 as shown in Figures 1, 2, 3, 4a or 4b. As shown in Figure 7b, the label 210 can be adhered, for example, to the object 200 to be marked.

As shown in FIG. 8, the layer structure 10 can be integrated into the object 200 as a constituent of the object 200. Therefore, it is conceivable that For example, a banknote has a layer structure as shown in Fig. 1, 2, 3, 4a or 4b as a whole, and the information item 20 is introduced onto the banknote 200 at a specific point of the layer structure 10.

10‧‧‧ layer structure

15‧‧‧Information pattern

20‧‧‧Information Project

30‧‧‧First conductive layer

35, 35'‧‧‧

40‧‧‧Substrate

45, 45'‧‧‧ District

50‧‧‧ dielectric

60, 60'‧‧‧ another conductive layer

70‧‧‧Protective layer, additional layer

80‧‧‧First steps

90‧‧‧ second step

100‧‧‧ third step

110‧‧‧ fourth step

120‧‧‧ illumination

130‧‧‧Capacity measuring device

131‧‧‧First measurement

132‧‧‧Second measurement

133‧‧‧ third measurement

134‧‧‧ fourth measurement

135‧‧‧ fifth measurement

136‧‧‧ sixth measurement

137‧‧‧ seventh measurement

138‧‧‧ eighth measurement

139‧‧‧ ninth measurement

140‧‧‧10th measurement

141‧‧‧11th measurement

142‧‧‧ twelfth measurement

143‧‧‧13th measurement

144 ‧ ‧ fourteenth measurement

145‧‧‧ fifteenth measurement

150‧‧‧Location 1

160‧‧‧Location 2

170‧‧‧Location 3

180‧‧‧Location 4

190‧‧‧Location 5

200‧‧‧ objects, banknotes

210‧‧‧ label

220‧‧‧ gap area

230‧‧‧x axis

240‧‧‧y axis

Figure 1 is a schematic view of a process for a layer structure, Figure 2a: a schematic view of a layer structure having a metal plate as a further conductive layer, Figure 2b: a layer having a conductive polymer as a layer of another conductive layer Schematic diagram of the structure, Figure 3: Schematic diagram of a layer structure, in which the capacitance system from at least one cell to one region is measured, Figure 4a: Schematic diagram of a layer structure, from at least one cell to one region and from at least one cell or one The capacitance from the region to the other conductive layer is measured. Figure 4b is a schematic diagram of a layer structure with an additional protective layer, wherein the capacitance from at least one cell or region to the other conductive layer is measured. Figure 5: The calculated capacitance is related to the capacitance measured for an information item in a plan view, Figure 6a-d: Schematic diagram of one of the settings listed below: 6a) Unstructured information pattern, 6b Using a UV laser structured information pattern, 6c) an information pattern covered by a protective layer, 6d) using the measurement configuration shown in Figure 4b for the measurement shown in Figure 6c The result of the graph, Figure 7a is a schematic view of an information pattern in the form of a layer structure on an object, Figure 7b: a schematic diagram of an information pattern in the form of a layer structure on an object, Figure 8: an information pattern in the form of a layer structure A schematic diagram of integration into an object.

10‧‧‧ layer structure

20‧‧‧Information Project

30‧‧‧First conductive layer

35, 35'‧‧‧

40‧‧‧Substrate

45, 45'‧‧‧ District

50‧‧‧ dielectric

60‧‧‧ another conductive layer

70‧‧‧Protective layer, additional layer

80‧‧‧First steps

90‧‧‧ second step

100‧‧‧ third step

110‧‧‧ fourth step

Claims (23)

A method for identifying an information item (20), comprising the steps of: a. providing a layer structure (10) comprising i. a dielectric (50), ii. The dielectric (50) is separated by at least one first conductive layer (30) and at least one other conductive layer (60), wherein the first conductive layer (30) comprises a conductive polymer, wherein The first layer (30) includes a cell (35, 35') having a surface resistance Z, wherein the cell (35, 35') is adjacent to a region (45, 45') having a surface resistance B, Wherein the surface resistance Z is lower than the surface resistance B; b. electrically contacting the first layer (30) during a period of less than 60 seconds, a capacitance is determined; c. comparing the capacitance and a corresponding The target value of the information item (20). The method of claim 1, wherein the surface resistance of the first conductive layer (30) and the surface resistance of the other conductive layer (60) differ by a maximum of 50,000 ohms/square. The method of claim 1 or 2, wherein the first conductive layer (30) has a higher surface resistance than the other conductive layer (60). According to the method of claim 1 or 2, a protective layer (70) is applied over the first conductive layer (30). The method of claim 4, wherein the surface resistivity of the protective layer (70) is in the range of 10 ⁵ to 10 ¹⁰ ohms/square. The method of claim 4, wherein the surface resistivity of the protective layer (70) is higher than a surface resistance of the conductive layer (30) and lower than a surface resistance of the dielectric (50). The method of claim 1 or 2, wherein the cell (35, 35') and the zone (45, 45') comprise the electrically conductive polymer. The method of claim 1 or 2, wherein the surface resistance B is lower than a surface resistance of the dielectric (50). The method of claim 1 or 2, wherein the at least one other electrically conductive layer (60) comprises a conductive polymer. The method of claim 1 or 2, wherein the electrically conductive polymer is PEDOT/PSS. The method of claim 1 or 2, wherein at least one of the conductive layers (30, 60) is transparent. The method of claim 1 or 2, wherein the first conductive layer (30) and the dielectric (50) are made of a flexible material. According to the method of claim 1 or 2, wherein Z/B <10. The method according to claim 1 or 2, wherein the color separation ΔE _{cell, region} between the cell (35, 35') and the _region (45, 45') is at most 4.5. The method of claim 1 or 2, wherein the capacitance between the first conductive layer (30) and the other conductive layer (60) is judged. According to the method of claim 1 or 2, wherein the capacitance between the cell (35, 35') and the region (45, 45') is judged. The method of claim 1 or 2, wherein the layer structure (10) comprises a first cell (35) and at least one other cell (35'), wherein the first cell (35) and the at least The capacitance between another cell (35') is judged. According to the method of claim 17, wherein a. the first cell (35) and the zone (45, 45'), or b. the at least one other cell (35') and the zone The capacitance between (45, 45') is judged. The method of claim 1 or 2, wherein the cells (35, 35') are disposed in an outer region of the layer structure (10). The method of claim 1 or 2, wherein the width of the cells (35, 35') is in the range of 0.01 mm to 1 cm. The method of claim 1 or 2, wherein the first conductive layer (30) comprises at least two cells (35, 35') that differ in length. The method of claim 1 or 2, wherein the dielectric (50) and the first conductive layer (30) are bonded to each other. The method of claim 1 or 2, wherein the other electrically conductive layer (60) is separable from the layer structure (10).