JP2001016022A - Method for varying frequency of resonance circuit and the resonance circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To vary a frequency to a necessary resonance frequency by setting the frequency to the necessary one higher than a prescribed frequency which is set previously by means of making a gap which is not conducted in a capacitor electrode board part. SOLUTION: A resonance circuit 1 is provided with electrode boards 8, which are formed on both sides of an insulating film and constitute a capacitor with an insulating film and a coil 5, which is electrically connected to the electrode boards. In the resonance circuit 1, L, C and R resonance circuits corresponding to prescribed resonance frequency are formed by the capacitor and the coil 5. In the resonance circuit reacting to the frequency, a gap which is not conducted is made in an electrode board part for reducing capacitor capacity. The overall capacitor capacity is reduced by the electrode boards 8a, etc., which are cut and the necessary frequency higher than that which is set previously to be a prescribed one can be obtained. The electrode boards 8a, etc., prevent the restoration of the frequency to the original one by making them minute.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resonance tag constituting a resonance circuit which resonates with a specific radio wave transmitted from a detection device, and the resonance tag is mounted by detecting the resonance frequency of the resonance tag. The present invention relates to a resonance tag that enables identification of a damaged article and confirmation of tampering.

[0002]

2. Description of the Related Art As is well known, a resonance tag is attached to a product at a department store, a discount store, a video rental store, a CD shop, or the like, and is used in a system for preventing shoplifting. This resonance tag is removed during the checkout process at the cash register. However, if the resonance tag has not been settled and passes through a gate having a built-in detection device installed in the store with the resonance tag attached to the product, a warning is given by a buzzer or the like.

A resonance circuit built in this resonance tag is generally formed by the following method. That is, 1
A metal film is formed on both sides of a thin film made of an insulating material having a thickness of about 0 μm to 30 μm, for example, a synthetic resin film. Next, one electrode plate of the capacitor and an electric circuit such as a coil electrically connected thereto are formed by the thin metal film, and the other electrode plate of the capacitor is formed by the thin metal film. By this process,
An L, C, R resonance circuit is formed.

FIG. 4 shows an equivalent circuit of the resonance circuit. The metal foils 2 and 4 and the dielectric 3 form a capacitor, and the resistance is formed by the resistance of the metal foils 2 and 4 itself. The resonance frequency F of this equivalent circuit is F = 1 / [2π
ＬＣ (LC)], and when a signal of this frequency is given from the detection device of the gate, it resonates to notify its existence.

[0005]

However, in response to the diversification of the frequency of the gate detection device, the demand for different frequency bands in nearby stores, the differentiation of the store itself from other stores, the demand for originality, etc. In order to manufacture and supply resonant tags of various frequencies, cost reduction is achieved in a considerable number,
At present, since the quantity is small and the price is high, there is an inconvenience in disseminating the above request.

The present invention has been made in view of the above-described problems, and has a resonance circuit having a popular frequency (mainly, a resonance circuit having a frequency of 8.
An object of the present invention is to provide a method of changing the frequency of a resonance circuit that can stabilize the price even for small lots by changing the frequency using (2 MHz), and to provide the resonance circuit.

[0007]

In order to achieve the above object, the present invention is responsive to a fixed frequency set by an antenna formed by a circuit patterned on a resin film serving as a dielectric and a capacitor electrode plate. By making a cut in the capacitor electrode plate portion that does not conduct to reduce the capacitance of the capacitor in the resonance circuit, the frequency of the resonance circuit is set to a required higher frequency than the predetermined frequency. A variable method and a resonance circuit thereof are provided.

In the present invention, when a cut is made in the capacitor electrode plate portion, in consideration of the fact that the portion once interrupted for electrical coupling is recombined and it is easy to return to the original frequency, the divided portion is further divided into smaller pieces. By doing so, we found prevention of recombination. In addition, the resonance circuit changed by this method has stable electric characteristics (resonance frequency, Q value, etc.) under normal use conditions such as low / high temperature (0 ° C. to 50 ° C.) and pressure (winding pressure). It is possible to maintain.

[0009] The adhesive used as the resonance tag label is an insulating material, but also has an effect of increasing and maintaining the insulating property due to the infiltration of the glue into the cut surfaces cut into small pieces.

Further, since the resonance circuit is attached to the product with the cut small pieces remaining, the small pieces remain on the adhered object when peeled off from the adhered object. It is a warning to the person, and it is possible to visually confirm the following.

As another means for achieving the above-mentioned object, the present invention is to respond to a fixed frequency set by an antenna formed by a circuit patterned on a resin film serving as a dielectric and a capacitor electrode plate. By adding a new electrode plate to the capacitor electrode plate portion in order to increase the capacitance of the capacitor in the resonance circuit, the frequency is set to a required lower frequency than the predetermined frequency. A method for changing a frequency and a resonance circuit thereof are provided.

In the present invention, as a method for newly adding an electrode plate, a capacitor electrode plate is provided by a method of attaching a metal foil, a printing method using a conductive ink, or the like, and is electrically connected to the original electrode plate. It is possible to change to a required low frequency.

Further, as another means for achieving the above-mentioned object, the present invention provides a method for controlling a fixed frequency constituted by an antenna formed by a circuit patterned on a resin film serving as a dielectric and a capacitor electrode plate portion. In the resonance circuit which reacts, the frequency of the resonance circuit is varied by changing the thickness of the film in order to increase or decrease the capacitance of the capacitor, thereby changing the predetermined frequency to a required frequency. A method and a resonant circuit thereof are provided.

In the present invention, the thickness of the synthetic resin film is varied by utilizing the physical properties of expansion and contraction. As a method, if the frequency is variable by mixing a foaming agent or air bubbles into the film, the capacitor capacity is varied by expanding or contracting by temperature, pressure, UV irradiation, etc., and the required resonance frequency is varied. It is possible to do.

[0015]

According to the present invention, the above-described means are taken, and in this configuration, the resonance circuit has a target frequency, and when a signal of this frequency is given from the detection device, the resonance circuit resonates and its existence is detected.

Furthermore, a resonance circuit having a plurality of resonance frequencies of the same size and the same pattern can be used for a plurality of purposes such as an identification system and prevention of falsification and forgery.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a plan view of a resonance circuit according to an embodiment of the present invention, FIG. 2 is a rear view of the resonance circuit shown in FIG. 1, FIG. 3 is a sectional view of FIG. 1, and FIG. It is a circuit diagram.

The resonance circuit according to the present invention is shown in FIGS.
As shown in FIG. 1, the electrode film 8 is formed on both surfaces of the insulating film 3 and includes a coil 6 electrically connected to the electrode plate 8 and the electrode plate 9 constituting the capacitor 6 together with the insulating film 3. The resonance circuit 1 includes a capacitor 6 and a coil 5
Thus, an L, C, R resonance circuit corresponding to a predetermined resonance frequency is formed.

It is generally desired that the resonance circuit 1 has a characteristic of resonating at a detection frequency of 8.2 MHz. The present invention provides a resonance circuit having a required frequency from the 8.2 MHz resonance circuit.

FIG. 5 is a plan view of a frequency-variable resonance circuit according to an embodiment of the present invention, FIG. 6 is a rear view of the resonance circuit shown in FIG. 5, and FIG. 7 is a sectional view of FIG. , FIG.
9 and FIG. 9 are plan views of the resonance circuit in which the cuts in FIG. 5 are further miniaturized.

The total capacitance of the capacitor is reduced by the cut electrode plates 8a and 9b, so that a required frequency higher than a predetermined frequency can be obtained. The electrode plates 8a and 9b are miniaturized to prevent returning to the original frequency. As a jig for cutting the capacitor electrode plate, the frequency is varied by a blade type such as a mainspring blade, an etching blade, a die-cut roll blade, or a laser.

Further, when the resonance tag formed by these methods is peeled off from an adhered article such as a product, the fine small pieces remain on the adhered article, so that the tag can be used for preventing falsification and forgery.

Also, the frequency can be varied by a method of dropping out with a punch or the like (FIGS. 10 and 1).
1).

FIG. 12 is a plan view of a frequency-variable resonance circuit according to an embodiment of the present invention.
Is a rear view of the resonance circuit shown in FIG. 12, and FIG. 14 is a sectional view of FIG.

The newly added electrode plates 11a and 12b are electrically connected to the electrode plates 8 and 9, respectively, so that the capacitance of the entire capacitor is increased and the required frequency is lower than a predetermined frequency. It can be. 5-1
The additional electrode plate is made of a metal foil of about 0 μm or a conductive material of about several μm.

FIGS. 15 and 16 are sectional views of a frequency-variable resonance circuit according to an embodiment of the present invention.

FIG. 15 shows uniform and fine closed cells formed by a foaming agent mixed in a resin film serving as a dielectric. The frequency can be changed to a high frequency by decreasing the capacitance of the capacitor as the film thickness increases.

FIG. 16 shows that the bubbles contained in the resin film serving as the dielectric are released to the outside, and the frequency is changed to a low frequency due to the increase in the capacitance of the capacitor as the film thickness decreases.

As the above-mentioned variable method, it is possible to control by utilizing the physical properties of expansion and contraction of the resin film by heating, pressurizing, UV irradiation, or the like. By changing the distance between them, that is, by changing the thickness of the resin film serving as the dielectric, the frequency can be changed from a preset frequency to a required frequency. Although the embodiments of the present invention have been described with reference to the drawings, the present invention is not limited to these embodiments.

[0031]

As described above, according to the method of varying the frequency of the resonance circuit according to the present invention, the area of the electrode plate constituting the capacitor is increased or decreased, or the dielectric film constituting the capacitor is formed as a thin film or a thick film. Thus, an original frequency that is set in advance, for example, a popular 8.2 MHz resonance circuit can be changed to a required frequency. In addition, since the resonance circuit thus changed has electrically stable properties, it can be stored for a long period without hindering the performance of the resonance circuit. As a conventional method, it is necessary to manufacture a resonance circuit based on each frequency, and a cost increase is inevitable for a small lot. Since the frequency is changed to a high frequency as in the first embodiment, the cutting method using the blade can be easily incorporated into the production process, and the production cost can be reduced. In order to change the frequency to a low frequency as in the second embodiment, the method of adding an electrode plate can reduce the production cost by incorporating a sticking step of a metal foil or the like into the production process, as described above. As in the third embodiment, in order to make it possible to freely change the frequency in either high or low frequency, if the composition of the dielectric film is different from that of the conventional product as a component of the resonance circuit, Since there is a degree of freedom in setting the conditions in the production process, the frequency can be adjusted freely, so that the production cost can be reduced in a series of processes. Further, there is an advantage that the stabilization of the price can be taken into consideration for a small lot by any of the methods, and the options on the user side are expanded.

[Brief description of the drawings]

FIG. 1 is a plan view of a resonance circuit according to an embodiment of the present invention.

FIG. 2 is a rear view of the resonance circuit shown in FIG.

FIG. 3 is a cross-sectional view of the resonance circuit.

FIG. 4 is an equivalent circuit diagram of the resonance circuit.

FIG. 5 is a plan view of a resonance circuit showing Example 1 in which the frequency is varied according to the embodiment of the present invention.

FIG. 6 is a rear view of the resonance circuit shown in FIG. 5;

FIG. 7 is a cross-sectional view of the resonance circuit.

FIG. 8 is a plan view of a resonance circuit in which a cut is made finer according to the first embodiment.

FIG. 9 is a plan view of the resonance circuit of the first embodiment, in which a cut is made fine.

FIG. 10 is a plan view of a resonance circuit formed by dropping out according to the first embodiment.

FIG. 11 is a cross-sectional view of the resonance circuit.

FIG. 12 is a plan view of a resonance circuit showing Example 2 in which the frequency is varied according to the embodiment of the present invention.

FIG. 13 is a rear view of the resonance circuit shown in FIG.

FIG. 14 is a cross-sectional view of the resonance circuit.

FIG. 15 is a cross-sectional view of a resonance circuit showing Example 3 in which the frequency is varied according to the embodiment of the present invention.

FIG. 16 is a cross-sectional view of a resonance circuit showing Example 3 in which the frequency is varied according to the embodiment of the present invention.

[Explanation of symbols]

 1 ---- Resonant circuit 2--conductive metal film 3--dielectric film 4--conductive metal film 5--coil 6 ---- capacitor 7 ---- conductive part 8--electrode Plate 8a-Cut partial electrode plate 9--Electrode plate 9b-Cut partial electrode plate 10A-Conductive terminal portion 10B-Conductive terminal portion 11a-Additional partial electrode plate 12b-Additional partial electrode plate 33-Thickened Dielectric film 34-Dielectric film thinned

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04B 5/02 G06K 19/00 H (72) Inventor Masashi Nishimura 10-33 Kamitemacho, Nishi-ku, Hiroshima City Miyake Co., Ltd. F term (reference) 5B035 AA04 BA02 BA03 BC00 5C084 AA03 AA09 BB22 BB40 CC35 DD07 DD87 EE07 GG18 GG71 5J046 AA16 AB13 PA07 QA04 5K012 AA04 AA05 AB05 AC06 BA02 BA18

Claims (7)

[Claims] 1. A resonance circuit responsive to a fixed frequency set by an antenna formed by a circuit patterned on a resin film serving as a dielectric and a capacitor electrode plate,
A method for varying the frequency of a resonance circuit, wherein a predetermined higher frequency than the predetermined frequency is set by making a cut in the capacitor electrode plate to reduce the capacitance of the capacitor. 2. A resonance circuit responsive to a fixed frequency set by an antenna formed by a circuit patterned on a resin film serving as a dielectric and a capacitor electrode plate,
By adding a new electrode plate to the capacitor electrode plate to increase the capacitance of the capacitor, the required frequency can be set lower than the predetermined frequency. Method. 3. A resonance circuit responsive to a fixed frequency set by an antenna formed by a circuit patterned on a resin film serving as a dielectric and a capacitor electrode plate,
A method for varying the frequency of a resonance circuit, characterized in that the predetermined frequency is changed to a required frequency by varying the thickness of the film so as to increase or decrease the capacitance of the capacitor. 4. A fixed frequency of 8.2 MHz
4. A resonance circuit according to claim 1, wherein
A method for varying the frequency of the resonance circuit described in the above. 5. A variable method according to claim 1, wherein a non-conductive cut is made in the capacitor electrode plate in order to reduce the capacitance of the capacitor, and the required frequency is set higher than a predetermined frequency. A resonance circuit characterized by the above. 6. A variable method according to claim 2, wherein a new electrode plate is added to the capacitor electrode plate in order to increase the capacitance of the capacitor, and the frequency is set to a required lower frequency than a predetermined frequency. A resonance circuit characterized by: 7. The variable method according to claim 3, wherein the thickness of the film is varied to control the increase or decrease of the capacitance of the capacitor, and the predetermined frequency is changed to a required frequency. Resonance circuit.