JP2616920B2 - Sheet-like resonant circuit and method of using the same to prevent copying of documents and theft of articles - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a sheet-shaped resonance circuit having a circuit pattern formed of a conductive polymer material.

[Prior Art] Conventionally, an electronic protection system using a resonant circuit tag that resonates at a specific frequency has been put into practical use. There are attempts to use this to prevent reading.

That is, a sheet-like resonance circuit that resonates with an electromagnetic wave of a specific frequency is present in at least a part of documents, and a resonance circuit detecting means is provided when a document approaches a certain area of a copying or reading device. This is to stop some or all of the copying and reading operations of the apparatus.

However, although the conventional sheet-shaped circuit has a conductor portion printed or printed with a metal foil such as an aluminum foil or conductive ink, these sheet-shaped resonance circuits are peeled off by bending or the like. It is difficult to apply to the above information protection system because it is easily broken and has a problem in reliability and is not paper-like.

On the other hand, with the development of electronic devices, diversification of circuit forms has been demanded, and accordingly, research on circuit materials according to purposes has been conducted. Among them, a circuit material formed by masking a polyacetylene film with a wet coating material to form a circuit pattern and exposing the circuit pattern to a dopant has been proposed (Japanese Patent Application Laid-open No.
-88205).

Although this circuit material is paper-like, it is important to prevent the diffusion of the dopant below the coated surface of the polyacetylene film, which would destroy the circuit, and in fact, it is necessary to manufacture a highly reliable circuit. Difficult to do.

[Object] The present invention is to provide a resonance circuit which does not have the above-mentioned problems, that is, is thinner, paper-like, easy to manufacture, and has high reliability.

The present invention also provides a method of using the resonance circuit to prevent copying and reading of documents or theft of articles.

[Structure] The present inventor has been studying a more paper-like circuit that does not have the above-mentioned drawbacks. However, a thin layer of a polymer material having conductivity itself is formed on an insulating thin film. Thus, the present inventors have found that this problem can be solved, and have completed the present invention.

That is, the present invention relates to a sheet-like test circuit that resonates with an electromagnetic wave of a specific frequency, wherein the resonance circuit forms a thin-layer circuit pattern of a polymer material having conductivity itself on an insulating thin film. According to a second aspect of the present invention, there is provided a sheet-like resonant circuit formed by forming a thin-layer circuit pattern of a polymer material having a conductive property on an insulating thin film. The use of the resonant circuit is characterized in that the information recorded in the document is prevented from being copied or read by causing the resonance circuit to exist. A method of using a resonance circuit, characterized in that a sheet-like resonance circuit formed by forming a thin layer circuit pattern of a polymer material having a property is present in at least a part of an article to prevent theft of the article. A.

The resonance circuit will be described more specifically with reference to the drawings. The resonance circuit has a configuration in which conductors as shown in FIGS. 1 and 2 are formed on both surfaces thereof with a thin insulating layer interposed therebetween. ing.

In the figure, reference numerals 44, 47 and 46, 49 denote portions forming capacitors, and 45, 48 denote portions forming inductors. The constants of the LC circuit formed by these are set by the L and C according to the pattern and the circuit resistance, whereby the resonance frequency can be controlled.

The conductor portion is made of a polymer material having conductivity itself, and is an electron conductive polymer material having an electric conductivity of 10 ⁻¹ S / cm ² or more.

Examples of such a polymer material include polyazulene, polyparaphenylene, polypyrrole, polythiophene, poly-3-methylthiophene, polyphenylenevinylene, and polyaniline.

Conductive parts made of these conductive polymers can be obtained by electrolytic polymerization on photo-etched electrodes, or by printing a polymerization catalyst on an insulating layer and contacting it with monomers under polymerization conditions. Can be formed. Generally speaking about the former method, J. Elektrochem.So
c., Vol. 130, No. 7, 1506-1509 (1983), Electrochem. Act
a., Vol. 27, No. 1, 61-65 (1982), J. Chem. Soc., Chem. Co.
As shown in mmun., 1199- (1984), a solution obtained by dissolving a monomer and an electrolyte in a solvent is placed in a predetermined electrolytic tank, the electrode is immersed, and an electrolytic polymerization reaction by anodic oxidation is caused. Can be done by

As the electrolyte salt, LiPF ₆ , LiSbF ₆ , LiAsF ₆ , LiCl
O ₄ , NaClO ₄ , KI, KPF ₆ , KSbF ₆ , KAsF ₆ , KClO ₄ , AgBF ₄ ,
NaBF ₄ , NaAsF ₆ , NaPF ₆ , [(n-Bu) ₄ N] ⁺ · AsF ⁶⁻ ,
[(N-Bu) ₄ N] ⁺ · ClO ₄ ⁻ , LiAlCl ₄ , or FeC
Examples thereof include catalysts used for the Friedel-Crafts reaction, such as l ₃ , AlCl ₃ AnCl ₂ , AlBr ₃ , and BF ₃ . Here, Bu represents a butyl group.

Examples of the solvent include acetonitrile, benzonitrile, propylene carbonate, γ-butyrolactone, cyclomethane, dioxane, dimethylformamide, and nitro solvents such as nitromethane, nitroethane, nitropropane, and nitrobenzene.

In addition to such starting materials (monomers), electrolyte components, and solvents, pyridine, 2,4,6-collidine, 2,6-
By adding an electron donating substance such as lutidine, the film formability can be improved.

As a material constituting the electrode at the time of electrolytic polymerization, for example, A
Examples include metals such as u, Pt, and Ni, metal oxides such as SnO ₂ and In ₂ O ₃ , and composite electrodes or coating electrodes thereof. In particular, when a metal oxide is used as the anode,
This is preferable because a high-strength polymer film can be obtained.

As the electrolytic polymerization, any of constant voltage electrolysis, constant current electrolysis, and constant potential electrolysis can be used. However, constant current electrolysis and constant potential electrolysis are suitable, and constant current electrolysis is particularly preferable from the viewpoint of mass productivity.

The above-mentioned insulating layer (which serves as a dielectric of the capacitor) constitutes the base of the sheet-shaped resonance circuit of the present invention. Such an insulating layer may be made of polyethylene, polyester, polypropylene, or special paper impregnated with resins, or a polyvinyl chloride,
A laminate obtained by laminating thermoplastic resins such as polyvinyl acetate, polyvinylidene chloride, polyvinylidene fluoride, polyacrylonitrile, and unsaturated polyester is used.

The resonance circuit of the present invention is thinner and more paper-like than the conventional one.Therefore, the resonance circuit of the present invention has no uncomfortable feeling even when attached to a document,
Since there is no fear of disconnection or the like, it is suitable for preventing copying and reading of information in a document. Also, a resonance circuit can be formed on the thin insulating layer as a recording medium.

It can also be used to attach it to an article to prevent its theft.

In other words, when an article with a resonance circuit is to be unjustly taken out of the store, a control area by an electromagnetic wave transmitted from the transmitting antenna is provided in the shop in advance, and the article must pass through this area without fail. In other words, the presence of the article in this area is detected by the receiving device, and it can be seen that the article is unjustly taken away.

For example, as shown in FIG.
Further, a signal whose frequency is changed in a range of ± 5 to 15% is transmitted to provide a control region, and a resonance frequency is set in this region.
If an 8 MHz resonance circuit exists, the electromagnetic wave received by the receiving antenna is attenuated near 8 MHz as shown in FIG.

In this case, 44 and 47 in FIGS. 1 and 2 break the intervening insulating layer to establish electrical continuity.

Next, the resonance circuit of the present invention will be described more specifically with reference to examples.

Example 1 A coating film of vinylidene chloride / unsaturated polyester 1/1 having a thickness of 5 μm was formed on both sides of a 20 μm polyester film, and a solution obtained by dissolving 0.1 M of FeCl ₃ in water / acetonitrile 1/1 was coated on one side of the film. The surface of FIG. 1 has the pattern of FIG. 1 and the other surface has the pattern of FIG.
Print so that 49 faces each other. Thereafter, the film was exposed to pyrrole vapor to form an insoluble and infusible polypyrrole conductive film on the film.

Example 2 A pattern of FIGS. 1 and 2 was formed by photo-etching Nesa glass, and a polypyrrole paratoluenesulfonic acid complex film was formed on this pattern by an electrolytic polymerization method. Next, the polypyrrole circuit pattern having a thickness of 20 μm was laminated with a polyethylene film interposed therebetween, and a sheet-like resonance circuit was formed by heat fusion.

[Effects of the Invention] As is clear from the above description, the resonance circuit according to the configuration of the present invention is more paper-like than the conventional one, has good compatibility with documents, and has a conductor part peeled off due to bending or the like. It has remarkable effects such as no disconnection and high reliability.

Further, by using this circuit, it is possible to more reliably prevent copying and reading of a document and prevention of theft of an article.

[Brief description of the drawings]

FIGS. 1 and 2 show patterns of conductors formed on both surfaces thereof with an insulating layer interposed therebetween, FIG. 3 shows an example of an electromagnetic wave transmitted from a transmitting antenna, and FIG. 4 shows a pattern received by a receiving antenna. Examples of electromagnetic waves.

Claims (3)

(57) [Claims] 1. A sheet-like resonance circuit that resonates with an electromagnetic wave of a specific frequency, wherein the resonance circuit is formed by forming a thin-layer circuit pattern of a polymer material having conductivity on itself on an insulating thin film. Resonance circuit. 2. A method according to claim 1, wherein a sheet-like resonance circuit formed by forming a thin layer circuit pattern of a polymer material having conductivity on the insulating thin film is present in at least a part of the document. The use of the resonance circuit, which prevents copying and reading of information recorded in the resonance circuit. 3. The theft of an article by providing a sheet-like resonance circuit formed by forming a thin circuit pattern of a polymer material having conductivity on itself on an insulating thin film in at least a part of the article. The use of the resonance circuit, wherein the resonance circuit is prevented.