JPS60142799A - Detection of goods - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for detecting a product, and more particularly to an improvement in a method for detecting a product suitable for use in a product theft prevention system and the like.

[Prior art and its problems]

In recent years, product theft prevention systems have been proposed in order to prevent products from being illegally removed from, for example, general retail stores and supermarket counters.

In this product theft prevention system, for example, as shown in FIG. When a product 5 to which a resonant circuit is attached passes between the transmitting and receiving antennas 2 and 3, a receiver 4 is connected to the receiving antenna 3 at a predetermined interval. The device 4 detects the presence of the resonant circuit and detects the passage of the product 5.

And in the detection method of such products.

For example, as shown in FIG. 2, a resonant circuit 9 is formed by forming a loop-shaped coil 7 on an insulating plate 6 and connecting a capacitor 8 to both ends of the coil 7. It is attached to the case 10 and its resonance circuit 9 is detected.

Incidentally, a circuit diagram of the resonant circuit 9 is shown as shown in FIG.

However, how to detect such products?

Since this method involves attaching one resonant circuit 9 to the product 5 and detecting the resonant circuit 9, there are the following problems.

That is, when a resonant circuit that resonates with the frequency of radio waves emitted from the transmitting antenna 2 is formed near the receiving antenna 3, the receiver 4 detects the resonant circuit, and the resonant circuit 9 attached to the product 5 Even though it does not pass between the transmitting and receiving antennas 2 and 3, it is detected as if it had passed.

Particularly in recent years, automatic doors are often installed at the entrances and exits of retail stores, etc., and metal materials are often arranged in a loop around the outer periphery of the automatic door, and the transmitting and receiving antennas 2 and 3 are It is generally placed near the entrance/exit. Therefore, it was found that the opening and closing operations of the automatic door tend to cause the door to easily form the same resonant circuit as the resonant circuit 9 temporarily attached to the product 5, and the receiver 4 easily detects this and operates.

Additionally, in addition to such automatic doors, objects that may form resonant circuits, such as chairs and baskets made of metal pipes, are likely to be placed near the transmitting/receiving antenna 2.3, and if these are detected, There are many.

In order to eliminate malfunctions of the product theft prevention system, it is extremely complicated to always take care to remove anything that may form a resonant circuit near the transmitting/receiving antenna 2.3, and it is necessary to prevent malfunctions. was becoming difficult.

[Purpose of the invention]

The present invention was made under these circumstances.

The object of the present invention is to provide a method for detecting products that can detect only products equipped with a resonant circuit.

[Structure and effects of the invention]

In order to achieve this object, the present invention attaches a plurality of resonant circuits having different resonance frequencies to a product, emits a plurality of radio waves that cause each of the resonant circuits to resonate, and places the product in an area sensitive to the emitted radio waves. , the energy change of the emitted radio waves by each of the resonant circuits is detected, and when the respective detection signals are aligned, the presence of the product is detected.

According to the configuration of the present invention, a plurality of resonant circuits with different resonance frequencies are attached to a product, and when all of these resonant circuits are detected, the product is detected. Even if a detectable resonant circuit happens to be formed in a resonator, it is extremely rare that all the resonant circuits of the product are formed, so only the product with a resonator attached can be reliably detected.

Therefore, the product theft prevention system can be easily managed and maintained, and its original purpose can be fully utilized.

[Embodiments of the invention]

The invention will be explained in detail below. Note that parts common to the conventional example are given the same reference numerals.

First, before explaining the product detection method of the present invention.

The detection device used in the present invention will be explained.

FIG. 4 is a block diagram showing one embodiment of the detection device used in the present invention.

In the figure, the detection device includes a transmitter 11 and a receiver 12, and is configured to detect a product 5 to which a resonant circuit is attached.

The transmitting device 11 has 9 frequencies, for example, 8 MHz and 13 MHz.
It is constructed by connecting a transmitting antenna 2 to a transmitter 13 that generates various types of high frequency waves.

The receiving device 12 is connected to the receiving antenna 3 and has an 8 M
A first receiving unit 1 that detects and outputs a high frequency signal of Hz.
4, a second receiving section 15 which is connected to the receiving antenna 3 and detects and outputs a 13 MHz high frequency signal, and when there is an output from both the first and second receiving sections 14 and 15, a detection signal is detected. AND circuit 16 that outputs
The display circuit 17 is configured to include a display circuit 17 that performs a detection display based on the output of the ND circuit 16.

A product 5, such as a cassette tape, that passes between the transmitting and receiving antennas 2 and 3 is housed in a product case 10 made of plastic molded into a flat box shape, as shown in FIG. 1 and 2nd resonant circuit 18.
19 are attached with adhesive tape or the like at two intervals.

The first and second resonators 18 and 19 each include a coil 21 in which a conducting wire is wound in a loop shape around the main surface of an insulating substrate 20 such as a piece of paper, as shown in FIG. It is formed from a capacitor 22 connected to both ends, and is formed into a thin card shape by sandwiching it between plastic films 23a and 23b.

The resonant frequency of the first resonant circuit 18 is, for example, 8M.
Hz, and the resonant frequency of the second resonant circuit 19 is 1
3MHz, and the frequencies are far apart from each other.

Next, using the above-mentioned detection device, the product 5 shown in FIG.
Explain how to detect.

The transmitting antenna 2 emits radio waves of 8 MHz and 13 MH2. Currently, there are various legal radio wave regulations regarding the emission of radio waves, so the radio waves are emitted with extremely low output. Therefore, the area where this radio wave can be detected or sensitive to this radio wave is an extremely narrow area 9, for example, a predetermined area near the exit of a retail store. The receiving antenna 3 is located in this predetermined area.
is arranged to face the transmitting antenna 3, and the product 5 is detected via the receiving antenna 3.

When the product 5 passes between the transmitting and receiving antennas 2 and 3, the receiving antenna 3 senses re-radiated radio waves from the resonant circuits 18 and 19 attached to the product 5. The high frequency signal generated by this radio wave is
The signals are outputted through the first receiving section 14 and the second receiving section 15, respectively, and added to the AND circuit 16. 1st and 2nd
The output signals from both the receiving sections 14 and 15 are sent to the AND circuit 1.
6, an output signal is output from the AND circuit 16 to the display circuit 17, and the 1 display circuit 17 displays the presence of the product 5.

On the other hand, if a resonant circuit resonating at 8 MHz or 13 MHz happens to exist in a predetermined area, the first receiving section 1
A signal is outputted from one of the four receiving sections 4 and the second receiving section 15, and is added to an AND circuit 16. However, since the output signals from the first and second receiving sections 14 and 15 are not applied to the AND circuit 16, the AND circuit 16 does not output any output signals to the display circuit 17. Therefore, the 9 display circuit 17 does not operate, and the presence of the product 5 is not detected.

In this way, only when the product 5 to which the two resonant circuits 18 and 19 are attached is located in the area sensitive to the radio waves emitted from the transmitting antenna 2, the device operates to detect the presence of the product 5. However, even if other resonant circuits happen to be formed in the vicinity of the transmitting/receiving antennas 2 and 3, the probability that all the resonant circuits 18 and 19 attached to the product 5 will be formed by chance is extremely small, resulting in malfunction. disappears.

In addition, in the present invention, the method for detecting the resonant circuits 18 and 19 of the product 5 is as described above.

Not limited to the example of detecting re-radiated radio waves from the resonant circuit 18.19, the radio waves from the transmitting antenna 2 are detected when the resonant circuit 18.19
Alternatively, after the radio waves emitted from the transmitting antenna 2 are cut off, the radiation of high-frequency energy stored in the resonant circuits 18 and 19 may be detected. It is also possible by In short, it is sufficient to detect each change in the radio wave energy emitted from the transmitting antenna 2 by the resonance circuits 18 and 19.

Furthermore, in the present invention, it is not necessary to simultaneously detect the resonant circuits 18 and 19. For example, as shown in FIG. 79, the first transmitting and receiving antennas 2a, 3a,
Using second transmitting and receiving antennas 2b and 3b.

The first and second transmitting/receiving antennas 2a such that the product 5 passes between the first transmitting/receiving antennas 2a, 3a and then passes between the second transmitting/receiving antennas 2b, 3b.

3a, 2b, and 3b can be arranged and detected. In this case, the configuration may be such that the detection signal from the first receiving antenna 3a is held and the presence of the product 5 is detected when the detection signals from the second receiving antenna 3b are collected.

In this way, the transmitting antenna 2 by the resonant circuit 18.19
．． Detection of changes in the emitted radio wave energies from 2a and 2b is not limited to the case where signals obtained simultaneously over three hours are detected, but may be detected one hour apart.

By the way, in the above-mentioned embodiment, it was explained that it is detected when the product 5 passes between the transmitting and receiving antennas 2.3, but it is also possible to arrange the transmitting and receiving antennas 2.3 on the same plane,
It is also possible to configure the product 5 to be detected when it passes near them.

Furthermore, the types of radio waves emitted by the transmitting device 11 in the present invention are not limited to two.

It is also possible to fire two or more types.

The frequencies can also be arbitrarily selected from different frequencies.

The number and resonance frequency of the resonant circuits 18 and 19 attached to the product 5 may be selected accordingly.

The above-mentioned first and second resonant circuits 18 and 19 attached to the product 5 can be placed at any position on the product 5, and they can be placed at any convenient location, whether on the same surface or on opposite surfaces. good.

Furthermore, the resonant circuit does not need to be configured separately into the first resonator 18 and the second resonator 19, and if a plurality of resonant circuits are formed on one substrate, it is possible to attach the resonant circuit to the product 5. Improves efficiency.

In addition to attaching the product 5 indirectly to the product 5 by pasting it on the product case 10 or other packaging means, attaching the product 5 to the product 5 using threads, strings, etc., or directly attaching the product 5 according to the present invention, It is possible to attach it by pasting it on.

In addition, the capacitor 22 constituting the resonant circuit 18, 19 can also utilize the distributed capacitance obtained between the conductors of the coil 21. In addition, the coil 21 can be wound with a conductor.
It may be formed by etching or the like from a printed circuit board or the like. The insulating substrate 20 forming the coil 21 can also be made of paper, a printed circuit board, a plastic film, or the like.

The thickness of the insulating material can be selected from a wide range, such as a relatively thick insulating material or a thin insulating material.

As explained above, the present invention emits a plurality of radio waves having different resonant frequencies, and when a product is located in an area sensitive to the emitted radio waves, the energy of the emitted radio waves is changed by the plurality of resonant circuits attached to the product. Since the presence of the product is detected when each detection signal is aligned, it is possible to prevent false detection of products other than those equipped with the resonant circuit.

Products equipped with the resonator of the present invention include records,
Relatively small items such as books, clothing, local stationery, miscellaneous goods, etc. that can be displayed and sold in moderate quantities are suitable.

[Brief explanation of drawings]

FIG. 1 is a diagram schematically showing a product theft prevention system. FIG. 2 is a schematic perspective view showing a conventional product equipped with a resonant circuit, FIG. 3 is a circuit diagram showing the resonant circuit, and FIG. 4 is a block diagram showing an embodiment of a detection device implementing the present invention. Fig. 5 is a schematic perspective view showing a product equipped with a resonant circuit used in the present invention, Fig. 6 is an exploded perspective view of the resonant circuit shown in Fig. 5, and Fig. 7 is a diagram showing another embodiment of the present invention. be. l, 13... Transmitter 2.2a, 2b, transmitting antenna 3.3a, 3b, receiving antenna 4.16... Receiver 5... Product (cassette tape) 7121...
・・Coil 8.22・・・Capacitor 9.18.19・Resonant circuit 10・・・Product case agent Patent attorney Miharu Saifuji 13−

Claims (1)

[Claims] A plurality of resonant circuits having different resonance frequencies are attached to a product, a plurality of radio waves are emitted that cause each of the resonant circuits to resonate, and when the product is located in an area sensitive to the emitted radio waves, the A method for detecting a product, characterized by detecting energy changes in emitted radio waves, and detecting the presence of the product when each detection signal is aligned.