EP0289551B1 - Method for protecting objects against theft and objects protected according to such method - Google Patents

Abstract

Method for the protection of objects against theft by adjoining to the object components which modify the emission characteristics of a magnetic or electromagnetic field. According to the invention, a circuit resonating at a predetermined frequency is integrated to the object so that it is accessible only by destroying it. Applications: combatting theft in shops.

Description

The present invention relates to a method of protecting objects against theft intended in particular, but not exclusively, for large surfaces distributing self-service products and the products obtained by this method. By object, we mean any material article and by packaging, any envelope which covers or attaches the article.

It has already been proposed in French patent No. FR-A-2 241 937 to provide each of the products with a label comprising a resonant circuit housed on the label, this circuit being formed from a very thin flat coil with a core of air and a flat capacitor. The resonant frequency (s) of this circuit is tuned to that of the radio frequency electromagnetic field of a surveillance barrier comprising a transmitter and a receiver. When the customer arrives at the cash register to pay for his purchases, the products purchased pass through the cash register, while he passes inside the security portal. If all the objects he has taken pass through the checkout, the electromagnetic waves pass through the customer and nothing happens. There is no change in the electrical state of the gantry since the waves do not encounter a resonant circuit. On the other hand, if the customer takes with him or with him an object provided with a protection label, without passing this object through the cash register, an alarm signal is triggered. Indeed, when a label carrying a circuit tuned to the frequency of the wave emitted by the transmitter, passes through the barrier, a certain amount of current is induced in the resonant circuit, and it follows that the receiver notices a reception level drops and triggers an alarm signal by means of a toggle.

It is also possible to deactivate the resonant circuit, as indicated in FR-A-2 272 571, at the level of the body located in front of the monitoring portal, and to make pass the customer and the items purchased through the portal.

The label including the resonant circuit can also be deactivated, either by sticking on the circuit a patch including at least one layer of metal, which shifts the resonant circuit in frequency and prevents the action of the field of the monitoring device. and consequently the triggering of the alarm when the client crosses the barrier.

It has also been proposed in application CH-A-407.82, to modify the resonance frequency of the circuit carried by the label by cutting a part of said circuit to interrupt the resonant circuit or modify its natural frequency, the heel of the label thus detached being kept at the checkout and containing the information necessary for the store for control purposes in the form of printed codes which can be read by machine.

There are also known security labels bearing one or more magnetized strips which can optionally be demagnetized during checkout. Of course, in the event of theft, these magnetic labels can, as before, trigger an alarm. However, this protection process should be avoided, especially in the case of magnetic recordings which can be altered.

Until now, the labels have been placed on the outside of the packaging so as to allow easy reading by readers, and possibly be able to be deactivated after payment at the checkout. The presence of these tags played a deterrent against theft at the start of their installation. They were indeed perfectly visible, which produced a psychological impact. But, the thieves quickly realized that it was enough to remove the label for the protection of the object to be removed. Thus in the evening there are a large number of labels on the store floors.

US-A-4,075,618 has already proposed to hide anti-theft labels sensitive to electromagnetic radiation or to a magnetic field, out of the sight of the purchaser. However, the proposed circuits are ill-suited to the desired goal.

The present invention aims to overcome the drawback resulting from the separation of the label and the product inside the store and aims to generalize the electronic protection of articles or objects offered for sale in self-service.

According to the present invention, the method of protecting objects against theft using a label carrying a flat resonant circuit used inside a gantry emitting an electromagnetic radio frequency wave using a flat resonant circuit composed of a coil and a capacity is characterized in that it consists in integrating at least one resonant circuit in the object itself and / or in its tamper-proof packaging, during manufacture, so that the circuit rendered invisible cannot be removed without destroying the object.

The circuit is directly integrated into the object and cannot be removed from it without the object being broken. Thus, the protection circuit is not only invisible which provides initial protection, but it is inaccessible, which prevents any neutralization maneuver. The integration of the circuit into the product is preferably carried out during the manufacture of the latter, during molding or thermoforming or by insertion between two layers in the case of laminated products.

In the event that integration into the product is materially impossible, it is carried out in the inviolable packaging which surrounds the object, for example, when a packaging contains several objects assembled on or in a support by the methods known in the art. technical under names of "Skin Pack" which consists of lamination, of "blister shell" whose edges are welded by ultrasound or high frequency or in the case of the shells obtained by folding or gluing. The resonant circuit is then included below the products, so as to be hidden by them.

According to another characteristic of the invention, a protection circuit is included in the product itself, a second circuit in its housing, and a third circuit in its packaging shell. In the event of theft for resale, the bare object itself may have only a reduced value compared to the resale price when the packaging is intact. It is therefore desirable to also protect the packaging and shells, although the intrinsic value of these is negligible.

The present invention relates in particular to the protection of products with high added value such as video cassettes, compact discs with laser reading, and audio cassettes. But of course, the invention can be implemented for all other objects such as "black" discs, shoes, books, hats.

Advantageously, the safety circuit included in the object or in its packaging, is a deactivable circuit, that is to say that it can be interrupted after a first passage in an electromagnetic field of appropriate frequency and power. . This deactivation can be obtained, for example, by providing a fuse-resistant part forming a safety lead on the circuit, but the circuit may very well remain in the state, since it is no longer called to pass through another gantry later. control.

• la figure.1, en perspective, une cassette-vidéo ;
• la figure 2, un boîtier de cassette-vidéo ;
• la figure 3, une coque thermoplastique pour cassette-vidéo ;
• la figure 4, en perspective, un disque-compact à lecture laser dans son boîtier ;
• la figure 5, une cassette-audio ;
• la figure 6, en perspective, un boîtier de cassette-audio ;
• la figure 7, une coupe du boîtier de la cassette.

Other characteristics and advantages of the present invention will appear during the description which follows of several embodiments, given solely by way of nonlimiting example, with reference to the drawings which represent:

• figure.1, in perspective, a video cassette;
• Figure 2, a video cassette housing;
• Figure 3, a thermoplastic shell for video cassette;
• Figure 4, in perspective, a laser-readable compact disc in its housing;
• Figure 5, an audio cassette;
• FIG. 6, in perspective, an audio cassette case;
• Figure 7, a section of the cassette housing.

In FIG. 1, the video cassette consists of two reels 1 and 2 on which the magnetic tape mounted inside a cassette 3 is wound. The protection can be arranged during the injection of the cassette 3 in any place on a wall thereof. In the example shown, the circuit C1 was introduced into the front front part of the cassette before the latter is loaded with the magnetic tape. It is also possible to introduce a circuit C2 on the flange of one of the coils 1 or 2, after manufacture of the cassette 3. In certain cases, it is also possible to integrate a circuit at the end of the strip, provided that there is no disturbance at the level of the read heads. The video cassette itself is thus protected, regardless of its packaging. We also know that these cassettes are housed, for distribution, in boxes such as the box 4 shown in Figure 2 which is advantageously made by thermoforming. Under these conditions, a circuit C3 is introduced into the same wall of the housing 4 during thermoforming. Finally, the casing 4 of the cassette is itself generally introduced, for self-service distribution, in a transparent thermoformed plastic shell 5 having hooking means 6 and a labeling zone 7, as shown in Figure 3. Advantageously, the security circuit is included at this time between the two folded parts of the label 7 for information or advertising, so that it is in no way apparent. As the shell is intended to be thrown away, the circuit C4 can be non-deactivable.

Preferably, the safety circuit used is presented, for reasons of convenience, in a rectangular shape whose dimensions are, for example, the following: 10 × 2 cm or 4 × 15 cm. Indeed, the circuits used until now were generally square in shape, which facilitated the production of flat coils, but presented problems of space when it came to integrating these labels into the product.

Figure 4 shows in perspective a compact disc 8 inside its housing generally designated by 9. The safety circuit is in this case, advantageously, arranged like the circuit C8 along the hinge. It is known in fact that a compact disc case comprises an opaque base portion 10, on which a transparent cover 11 can be folded down generally containing an information booklet. The particular problem which arises in the case of compact discs stems from the fact that they comprise a metallized surface which disturbs or inhibits the reception of radio frequency radiation so that, if the security label is placed on or under the protection becomes ineffective. It is therefore essential to have the safety circuits outside the area constituting the grip of the disc 8 and, as shown in C7 in FIG. 4, inside the opaque bottom 10.

Figures 5, 6 and 7 show an application of the invention to audio cassettes which, in particular because of their small dimensions, are very attractive to thieves. FIG. 5 represents a conventional cassette 12, FIG. 6 an injected housing 18 allowing the protection of the cassette 12, this housing 13 usually being produced by injection of plastics. An audio cassette case 13 generally comprises an opaque base on which a transparent cover, for example made of crystal polystyrene, is articulated. In the method according to the invention, it is possible, either at the time of constitution of the housing of the cassette 12, introduce a C5 label into the mold. But, if this operation presents difficulties, the protection may relate only to the housing, a label C6 being introduced above the outer layer of the bottom 14 and covered by a layer 15 of material identical to the material constituting the bottom 14 and welded on it by microwave or ultrasound.

Although the foregoing description has been given with the use of a radio frequency resonant circuit detector, the present invention can also be implemented with a magnetic circuit.

Claims (6)

1/ A method of protecting objects against theft by means of a label carrying a flat resonant circuit constituted by a coil and a capacitor, said resonant circuit being used inside a gate emitting a radio frequency electromagnetic wave, the method being characterized in that it consists, during manufacture, in integrating at least one resonant circuit (C) inside the object and/or its tamper-proof packaging so that the circuit thus made invisible cannot be removed without destroying the object.

2/ A method according to claim 1, characterized in that, when the object is mounted in a support, a second resonant circuit (C) is included inside the support of the object.

3/ A method according to claim 1 or 2, characterized in that a third circuit (C) is disposed inside the packaging blister.

4/ A method according to any one of claims 1 to 3, chacterized in that the circuit (C) is deactivatable.

5/ A resonant circuit for implementing the method according to any one of claims 1 to 4, characterized in that the flat coil (C) is rectangular in shape.

6/ Objects protected by integrating resonant circuits according to the method of any one of claims 1 to 4.

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