JPH0830876A - Resonance label - Google Patents

Abstract

PURPOSE:To provide a resonance label which has a simple constitution and us easy to produce and surely keeps the inactive state. CONSTITUTION:A first capacitor C1, a second capacitor C2, and an induction coil 30 are formed in a resonance label 1, and a part of the induction coil 30 is coated with a pressure-sensitive or thermosensitive conductive film 50. The pressure-sensitive conductive film has an insulating property without an applied pressure but has the resistance value reduced in accordance with the increase of the applied pressure. The thermosensitlve conductive film has an insulating property at a room temperature but is more conductive at a higher temperature, and it doesn't react on heat generation due to the current flowing to the induction coil 30 and has an insulating property still when the resonance label resonatese to the electromagnetic wave or a normal power density emitted at the exit of a shop or the like, but it reacts on heat generation due to the current flowing to the induction coil 30 to become conductive when the resonance label resonates to the electromagnetic wave of a high power density emitted by a casher. Consequently, this resonance label 1 can be inactivated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resonance label provided with a resonance circuit for electromagnetic waves and, for example, to a resonance label attached to a product or the like for the purpose of preventing theft.

[0002]

2. Description of the Related Art Conventionally, a resonance label for theft prevention is known which is attached to a product for the purpose of preventing the product from being illegally or erroneously taken out from a retail store or the like. Such a resonance label has a specific frequency (resonance frequency)
A resonance circuit that resonates with the electromagnetic wave is formed. If you attempt to illegally take a product with this resonance label out of the store, the resonance circuit of the resonance label will resonate with the electromagnetic waves of the frequency that matches the resonance frequency emitted at the outlet of the store, causing resonance. The presence of the label is detected by a detection device such as a security system and an alarm is issued. Therefore, it is necessary to inactivate the resonance label so that the alarm does not sound when the product is legally taken out through the cashier. Therefore, the resonance label is provided with a means capable of being inactivated.

In a conventional general resonance label, an insulating carrier layer is sandwiched between a pair of capacitor plates to form a capacitor, and the capacitor is electrically connected to an induction coil formed on one surface of the carrier layer. A resonant circuit is formed by connecting the two. Then, as a deactivating means, a target-dielectric breakdown site is formed in which a part of the capacitor is brought close to both capacitor plates with an extremely small gap of 0.1 to 1 μm, and a frequency matching the resonant frequency of the resonant circuit is formed. Electromagnetic waves with sufficiently large energy are applied with a cashier to cause discharge at the target-dielectric breakdown site, and the filament-shaped metal conductors generated between the capacitor plates by the discharge short-circuit the capacitor plates. It is known (Tokuyohei 4-505820).

[0004]

However, the present inventors have revealed that the resonance label described in Japanese Patent Publication No. 4-505820 has the following problems. That is, the distance between both capacitor plates at the target-dielectric breakdown site is 0.1 to 1 μm.
In order to obtain m, it is necessary to perform processing with high accuracy using a laser or the like, which complicates the process and significantly increases the manufacturing cost. On the other hand, if the processing accuracy is relaxed to suppress the manufacturing cost, individual labels In the above, the distance between both capacitor plates may vary, and a label that is not inactivated may be manufactured.

Further, the filamentous metal conductor generated by the discharge is weak in mechanical adaptability, and after being inactivated by the cashier,
If stress is applied to the thread-shaped metal body by pressing the resonance label with your hand, the thread-shaped metal conductor will break,
There is also the drawback that the resonant circuit becomes active again.

The present invention has been made in view of the above-mentioned points, and an object thereof is to provide a resonance label which has a simple structure, is easy to manufacture, and can surely maintain an inactive state. To provide.

[0007]

In order to achieve the above object, the invention according to claim 1 is a resonance label provided with a resonance circuit having at least one induction coil, wherein at least a pair of coil windings of the induction coil is provided. Across the section,
It is characterized in that a pressure-sensitive conductive film or a heat-sensitive conductive film is provided.

According to a second aspect of the present invention, in a resonance label provided with a resonance circuit having at least one induction coil, at least a portion corresponding to a coil window surrounded by the induction coil has a high power density and The present invention is characterized in that a heat-sensitive conductive film is provided which reacts with heat generated by a large current flowing through the induction coil when it resonates with an electromagnetic wave that matches the resonance frequency, and becomes conductive.

[0009]

According to the invention of claim 1, since the pressure sensitive conductive film or the heat sensitive conductive film is provided over at least a pair of coil winding portions of the induction coil, the resonance label is
When brought close to an inactivating device that generates electromagnetic waves having a high power density and a resonance frequency, a large current flows in the resonance circuit of the resonance label. The current causes the induction coil to
Heat is generated due to the resistance of the coil, and the heat-sensitive conductive film becomes conductive in response to the heat. As a result, the adjacent coil windings are short-circuited, the resonance frequency is shifted, or the signal strength is weakened, and the resonance label is inactivated. It is also possible to short-circuit by applying hot air to the heat-sensitive conductive film. Further, in the case of the pressure-sensitive conductive film, the coil winding portions are short-circuited by pressing this, so that the resonance label is inactivated.

According to the second aspect of the invention, at least a portion corresponding to the coil window portion surrounded by the induction coil resonates with an electromagnetic wave having a high power density and a resonance frequency, and a large current flowing through the induction coil. Since it has a heat-sensitive conductive film that becomes conductive in response to heat generated by the resonance label, when this resonance label is brought close to an inactivating device that generates an electromagnetic wave having a high power density and a resonance frequency, a resonance circuit of the resonance label is generated. A large current flows. The current generates heat in the induction coil due to the resistance of the coil, and the heat-sensitive conductive film becomes conductive in response to the heat. As a result, an effect equivalent to that of attaching a metal foil to the coil window portion to shield the electromagnetic field is obtained, and the resonance label is inactivated.

[0011]

EXAMPLE An example of a resonance label according to the present invention will be described below with reference to FIGS. (First Embodiment) FIG. 1, FIG. 2 and FIG.
It is a top view, a bottom view, and a longitudinal section of a resonance label of an example.

As shown in FIGS. 1 and 3, the resonance label 1 is provided with a third label on the upper surface 10a of the insulating carrier layer 10, for example.
2 and 3 are formed, while the first capacitor plate 21, the second capacitor plate 22 and the induction coil are formed on the lower surface 10b of the carrier layer 10 as shown in FIGS. 30 is formed. And the induction coil 3
A part of 0 is covered with a pressure-sensitive or heat-sensitive conductive film 50.

The resonance circuit of this resonance label 1 has a carrier layer 1
A first capacitor C1 made up of a first capacitor plate 21 and a third capacitor plate 23 facing each other with 0 sandwiched between them, and a second capacitor plate 22 and a fourth capacitor plate 24 facing each other with the carrier layer 10 sandwiched therebetween. It is composed of a second capacitor C2 made of the above and the induction coil 30.

The pressure-sensitive conductive film is a film that exhibits insulating properties when no applied pressure is applied, but has a resistance value that decreases as the applied pressure increases. For example, conductive carbon particles,
A conductive film in which carbon particles coated with a metal such as Ni, Cu, Pd, or Pt by electroless plating, transition metal particles, or metal particles coated with a carbonaceous or nitrogen-containing carbon material is mixed with a synthetic resin is used. it can. The heat-sensitive conductive film is a film that is insulative at room temperature, but becomes more conductive as the temperature rises. For example, synthetic resin paints containing various conductive fillers are enclosed in heat-sensitive microcapsules. Things can be used. The type of film-forming resin for the pressure-sensitive or heat-sensitive conductive film is not particularly limited, and soft resins such as polyurethane, polyester, polyamide, vinyl chloride-vinyl acetate resin, ionomer resin, and phenol resin can be used. Can be used. In addition, the heat-sensitive conductive film does not react to heat generated by the current flowing through the induction coil 30 when it resonates with an electromagnetic wave of a normal power density generated at the outlet of a store or the like, and remains insulative. When resonated with the emitted high-power-density electromagnetic wave, a reaction occurs due to the heat generated by the current flowing through the induction coil 30 and exhibits conductivity. The threshold temperature indicating the conductivity is, for example, about 50 to 200 ° C.

The pressure-sensitive or heat-sensitive conductive film 5
0 is the coil window 31 surrounded by the induction coil 30 and the first
On the entire area sandwiched between the condenser plate 21 of
The induction coil 30 is formed so as to fill a space between adjacent coil winding portions. Therefore, the pressure-sensitive conductive film or the heat-sensitive conductive film 50 becomes conductive, so that the adjacent coil winding portions are electrically connected to each other. Here, the coil winding portion is a wiring pattern portion for each turn of the induction coil 30.

Therefore, the resonance label 1 is used by being attached to a product or the like, and the presence of the resonance label 1 is detected by the security system by the resonance circuit resonating with the electromagnetic wave of the resonance frequency. However, when the film 50 is heat-sensitive conductive when passing through the cashier, electromagnetic waves with high power density are generated by the cashier, and when the film 50 is pressure-sensitive conductive, a predetermined pressure is applied by the cashier. It is inactivated by being pressed.

The induction coil 30 is wound, for example, in thirteen layers and is formed continuously with the first capacitor plate 21 and the second capacitor plate 22, one end of which is connected to the first capacitor plate 21 and the other thereof. The ends are electrically connected to the second capacitor plate 22, respectively. The third capacitor plate 23 and the fourth capacitor plate 24 are electrically connected to each other via a bridge conductor 40.

The first capacitor C1 is an induction coil 3
It is located outside 0. The second capacitor C2 is arranged in the center of the coil window portion 31 and apart from the induction coil 30. Although not particularly limited,
In FIG. 2, the induction coil 30 is formed in a substantially rectangular spiral pattern, and the center point (not shown) of the substantially rectangular second capacitor plate 22 is a substantially rectangular coil window portion 31. It coincides with the intersection of the diagonal lines (not shown).

Each of the condenser plates 21, 22,
Although not particularly limited, 23, 24, the induction coil 30 and the cross-linking conductor 40 are formed, for example, by pattern-forming an aluminum foil, and the carrier layer 10 is made of, for example, a polyolefin film such as polyethylene or polypropylene.

The resonance label 1 configured as described above is manufactured, for example, as follows. First, an aluminum foil having no pattern is adhered to the lower surface 10b and the upper surface 10a of the carrier layer 10 via an adhesive agent. Then, a photoresist (photosensitive resin) is further applied to the lower aluminum foil, and the patterns of the first capacitor plate 21, the second capacitor plate 22 and the induction coil 30 are transferred by the photolithography technique and etched. Form the pattern on the aluminum foil.
On the other hand, similarly, the pattern of the third capacitor plate 23, the fourth capacitor plate 24, and the bridge conductor 40 is formed on the upper aluminum foil by the photolithography technique and the etching. Then induction coil 3
The pressure-sensitive or heat-sensitive conductive ink described above is printed on the surface of the substrate 0 to form the pressure-sensitive or heat-sensitive conductive film 50. The resonance label 1 is completed by the above procedure.

The resonance label 1 having the above-described structure is inactivated as follows. That is, when an electromagnetic wave having a high power density and a frequency matching the resonance frequency of the resonance circuit of the resonance label 1 is applied to the resonance label 1, an excessive current flows in the resonance circuit, causing the induction coil 30 to move to the coil 30. Heat is generated due to the resistance of. When the film 50 is heat-sensitive conductive, its heat generation causes the film 50 to be heated to a temperature equal to or higher than a threshold value and change from insulating property to conductive property, and adjacent coil winding parts are short-circuited with each other or the resonance frequency is increased. The resonance label 1 is inactivated due to the deviation of the signal and the weakening of the signal intensity.
Alternatively, when the film 50 is pressure-sensitive conductive, by strongly pressing the label, the film 50 changes from insulating to conductive, short-circuiting adjacent coil windings, or causing a resonance frequency. The resonance label 1 is inactivated due to a shift or a weak signal strength.

According to the first embodiment described above, the pressure-sensitive or heat-sensitive conductive film 50 becomes conductive, so that the induction coil is short-circuited and the resonance label 1 is inactivated. The inactivated state is maintained without being reactivated if the reaction of expressing the conductivity due to pressure or heat of the pressure-sensitive or heat-sensitive conductive film 50 is irreversible. Further, since the pressure-sensitive conductive film or the heat-sensitive conductive film 50 can be easily formed into a desired pattern by printing, it is not possible to provide the pressure-sensitive conductive film or the heat-sensitive conductive film 50 as an inactivating means. It is extremely effective in industrial production. Therefore, it is possible to obtain the resonance label 1 which has a simple structure, is easy to manufacture, and can surely maintain the inactive state.

On the lower surface 10b of the carrier layer 10, the first capacitor plate 21 and the induction coil 30 are provided.
And the second capacitor plate 22 are electrically connected to each other, while on the upper surface 10a of the carrier layer 10, the third capacitor plate 23 and the fourth capacitor plate 24 are electrically connected to each other. Through the through holes formed in the carrier layer 10 because they are electrically connected to each other.
Therefore, it is not necessary to perform the conventional short-circuiting process of directly contacting the upper and lower conductors sandwiching each other to secure electrical continuity. Therefore, the conventional resonance label had a drawback that the manufacturing process was complicated due to the short-circuit treatment, but according to the present embodiment, the defect is eliminated and the manufacturing process is simplified. In addition, the manufacturing cost can be significantly reduced. In addition, the conventional resonance label has a drawback that it is difficult to obtain the resonance characteristic as designed due to the contact resistance in the short-circuit processing portion. However, according to the present embodiment, the drawback is eliminated and the resonance characteristic as designed can be obtained. In addition, mechanical strength is sufficiently secured.

Further, the second capacitor C2 is arranged at the center of the coil window portion 31 and apart from the induction coil 30, and the first capacitor C1 is connected to the induction coil 3.
Since it is arranged outside 0, the magnetic flux generated by the current flowing in the induction coil 30 at the time of resonance causes the magnetic flux generated by the second capacitor C
As the effective area of the resonance label 1 increases, the Q value of the circuit also increases, and the signal strength of the resonance label 1 increases.

The fact that the signal strength has increased has been confirmed from the results of the verification conducted by the present inventors. Although the verification result is not shown in the drawing, the frequency characteristics of the signal intensity at resonance are shown for the resonance label 1 of the present embodiment and the resonance label (comparative example) having no pressure-sensitive or heat-sensitive conductive film 50. As a result of examination, it was confirmed that the resonance label 1 of the present example had a stronger signal intensity. Further, in the present example, the resonance frequency (frequency at each peak of the frequency characteristic) was deviated to the lower frequency side than in the comparative example, but the cause of the deviation was variation due to the design of the induction coil and the capacitor, and in particular, It is considered that the amount of deviation is such that no problem occurs. Generally, if the resonance frequency shifts to the low frequency side, Q
Although the value becomes smaller, the Q value is considered to be larger than that of the comparative example in the result of the verification experiment because the signal strength of the present embodiment is stronger.

In the first embodiment, the pressure-sensitive or heat-sensitive conductive film 50 is formed on the entire area sandwiched between the coil window portion 31 and the first capacitor plate 21. However, the present invention is not limited to this, and may be formed so as to straddle at least a pair of coil winding portions. For example, as a resonance label 2 shown as a modified example in FIG.
The pressure-sensitive conductive film or the heat-sensitive conductive film 51 may be formed in a part of the region sandwiched between the coil window portion 31 and the first capacitor plate 21.

(Second Embodiment) FIG. 5 is a longitudinal sectional view of a resonance label according to a second embodiment. The resonance label 3 of the second embodiment differs from the first embodiment in that the upper surface 10a of the carrier layer 10 is different.
A pressure-sensitive conductive film 52 or a heat-sensitive conductive film 52 is adhered to the entire surface of the side, that is, the surface on which the pattern of the third capacitor plate 23, the fourth capacitor plate 24 and the bridge conductor 40 is formed, with an adhesive. This is the point that the structure is attached. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

The pressure-sensitive conductive or heat-sensitive conductive film 52 is the same pressure-sensitive or heat-sensitive conductive ink as in the first embodiment. Further, a paper 60 on which a bar code or the like is printed is stuck on the pressure-sensitive or heat-sensitive conductive film 52 to protect the film 52.

According to the second embodiment, when the resonance label 3 is brought close to an inactivating device which generates an electromagnetic wave having a high power density and a resonance frequency, an excessive current is applied to the resonance circuit of the resonance label 3. Flowing. The current generates heat in the induction coil 30 due to the resistance of the coil 30, and when the film 52 is heat-sensitive conductive, the film 52 becomes conductive in response to the heat. Alternatively, if the membrane 52 is pressure sensitive conductive, pressing the label strongly
The film 52 changes from insulating to conductive. Thereby,
The same effect as that obtained by attaching a metal foil to the coil window portion 31 to shield the electromagnetic field is obtained, and the resonance label 3 is inactivated. Therefore, it is possible to obtain the resonance label 3 which has a simple structure, is easy to manufacture, and can surely maintain the inactive state.

In the second embodiment, the pressure-sensitive conductive film 52 or the heat-sensitive conductive film 52 is formed on the entire surface of the resonance label 3.
However, the present invention is not limited to this, and may be such that the coil window portion 31 is almost covered with the pressure-sensitive conductive film or the heat-sensitive conductive film 52.

[0031]

According to the invention described in claim 1, since the pressure-sensitive conductive film or the heat-sensitive conductive film is provided over at least a pair of coil winding portions of the induction coil, a high power density and a high resonance frequency can be obtained. When it is brought close to an inactivating device that generates electromagnetic waves, a large current flows into the resonance circuit of the resonance label and heat is generated.In the heat-sensitive conductive film, the heat becomes conductive and the induction coil is short-circuited. Or the resonance frequency is shifted or the signal strength is weakened, and the resonance label is inactivated. It is also possible to short-circuit by applying hot air to the heat-sensitive conductive film. Further, in the case of the pressure-sensitive conductive film, the coil winding portions are short-circuited by pressing this, so that the resonance label is inactivated. This inactivated state is maintained without being reactivated once it is inactivated if the reaction of expressing the conductivity of the pressure-sensitive or heat-sensitive conductive film is irreversible. Further, since the pressure-sensitive conductive film or the heat-sensitive conductive film can be easily formed into a desired pattern by printing, it is industrial production to provide the pressure-sensitive conductive film or the heat-sensitive conductive film as an inactivating means. It is extremely effective.

Therefore, it is possible to obtain a resonance label which has a simple structure, is easy to manufacture, and can surely maintain the inactive state.

According to the second aspect of the present invention, at least a portion corresponding to the coil window portion surrounded by the induction coil has a large current flowing through the induction coil when it resonates with an electromagnetic wave having a high power density and a resonance frequency. Since it has a heat-sensitive conductive film that becomes conductive in response to heat generated by the resonance label, when this resonance label is brought close to an inactivating device that generates an electromagnetic wave having a high power density and a resonance frequency, a resonance circuit of the resonance label is generated. A large current flows. The current generates heat in the induction coil due to the resistance of the coil, and the heat-sensitive conductive film becomes conductive in response to the heat. As a result, an effect equivalent to that of attaching a metal foil to the coil window portion to shield the electromagnetic field is obtained, and the resonance label is inactivated. Therefore, it is possible to obtain a resonance label which has a simple structure, is easy to manufacture, and can reliably maintain the inactive state.

[Brief description of drawings]

FIG. 1 is a top view of a first embodiment of a resonance label according to the present invention.

FIG. 2 is a bottom view of the first embodiment of the resonance label according to the present invention.

FIG. 3 is a vertical sectional view taken along the line III-III in FIGS. 1 and 2 of the first embodiment of the resonance label according to the present invention.

FIG. 4 is a vertical sectional view of a modified example of the first embodiment.

FIG. 5 is a vertical sectional view of a resonance label according to a second embodiment of the present invention.

[Explanation of symbols]

 1, 2, 3 Resonance label 30 Induction coil 31 Coil window 50, 51, 52 Pressure-sensitive or heat-sensitive conductive film

 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Shoichi Makimoto 3-6-8, Kutaro-cho, Chuo-ku, Osaka City, Osaka Prefecture Toyo Aluminum Co., Ltd. (72) Nobuyuki Nakato Hisataro-ku, Chuo-ku, Osaka City, Osaka No. 6-8 Toyo Aluminum Co., Ltd. (72) Inventor Masanobu Konan 3-5-13 Kiyomidai, Kawachinagano City, Osaka Prefecture

Claims (2)

[Claims] 1. A resonance label provided with a resonance circuit having at least one induction coil, wherein a pressure-sensitive conductive film or a heat-sensitive conductive film is provided across at least a pair of coil winding portions of the induction coil. Characteristic resonance label. 2. A resonance label including a resonance circuit having at least one induction coil, wherein at least a portion corresponding to a coil window surrounded by the induction coil is resonant with an electromagnetic wave having a high power density and a resonance frequency. A resonance label comprising a heat-sensitive conductive film which is electrically conductive in response to heat generated by a large current flowing through the induction coil.