JPH07312569A - Supervisory equipment - Google Patents

Abstract

PURPOSE:To obtain a supervisory equipment with less malfunction whose power consumption is saved by providing an object proximity detection means to the equipment body and a transmission control means allowing the transmission of a supervisory information acquisition signal from a transmitter only while the detection means is detecting an object. CONSTITUTION:A power supply unit 7 connecting to a commodity mount board 5 by a cord is provided with a transmission control means 6 controlling the transmission of a supervisory information acquisition signal from an antenna 9 and a power supply means converting power for signal transmission from a 100V commercial power supply and supplying the power. Only when a photoconductive cell 10 senses the presence of a commodity M on the commodity placing plate 5, the control means 6 allows the transmission of the supervisory information acquisition signal from the antenna 9. That is, while the commodity M is place on the placing plate 5 of a register R for the count, a radio wave with much power consumption is sent to save power to take forgotten tag. Furthermore, malfunction of activating a warning means A only by passing of a person in the vicinity of the register R.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is provided with a transmitting device for transmitting a monitoring information acquisition signal to a surveillance tag carried by a surveillance object, and the transmission device is provided in at least one of the device body and the surveillance tag. A monitoring device provided with an alarm means for issuing an alarm based on the monitoring information obtained in response to the transmission of the monitoring information acquisition signal, for example, a product to be monitored is stolen as a monitoring tag. Monitoring information from the sending device when a device with a sending device is installed in the gate at the entrance of the store with a prevention tag attached and you try to leave the gate with a product that does not pass through the cash register By receiving a signal for acquisition and obtaining monitoring information that the anti-theft tag is still attached to the product, and sounding a buzzer, etc., it is possible to prevent theft in advance. On.

[0002]

2. Description of the Related Art When using the above-mentioned anti-theft system using a monitoring device, the tag is usually removed at the cash register, but if you forget to do so, an alarm will sound at the gate even if you purchased it legally. When the tag attached to the product brought to the cash register receives the signal for monitoring information acquisition, the device main body with the transmitter is placed near the cash register because it may cause discomfort to customers. There is proposed a method in which the same or another alarm is issued to prompt the store clerk to remove the tag. And in those monitoring devices, whether the device main body equipped with the transmitter is installed in the gate or placed near the cash register,
It has been constructed such that the signal for monitoring information acquisition is always transmitted from the transmitting device.

[0003]

Therefore, a large amount of power is constantly consumed for transmitting the monitoring information acquisition signal, and particularly when a transmitter is provided near the cash register, the signal is passed near the cash register. In some cases, the alarm means was activated just by hanging it. In view of the above situation, an object of the present invention is to provide a monitoring device that consumes less power and that alarm means is less likely to operate unnecessarily.

[0004]

A first characteristic configuration of a monitoring device according to the present invention is to monitor a device body provided with a transmitting device for transmitting a monitoring information acquisition signal to a monitoring tag carried by a monitoring target. The object proximity detection means for detecting the proximity of the object is provided, and the transmission control means for allowing the transmission of the monitoring information acquisition signal from the transmission device only during the object proximity detection by the object proximity detection means is provided. is there.

A second characteristic configuration of the monitoring apparatus according to the present invention is the same as the first characteristic configuration, except that the transmission control means is configured so that the transmission from the transmission apparatus is performed only during the object proximity detection by the object proximity detection means. The transmission state switching means is provided for switching between a state in which transmission of the monitoring information acquisition signal is permitted and a state in which the monitoring information acquisition signal is always transmitted from the transmission device.

Further, a third characteristic configuration of the monitoring apparatus according to the present invention is the same as the first characteristic configuration or the second characteristic configuration, in which the object proximity detection start timing by the object proximity detection means is included in the transmission control means. Therefore, the transmission period control means for allowing the transmission of the monitoring information acquisition signal from the transmission device only for a predetermined period is provided.

According to a fourth characteristic configuration of the monitoring apparatus of the present invention, in the third characteristic configuration, the transmission control means is configured such that the object proximity detection means constantly monitors the object proximity detection means. Equipped with transmission period switching means for switching between a state in which the information acquisition signal is transmitted and a state in which the transmission of the monitoring information acquisition signal from the transmission device is permitted only for a predetermined period from the target proximity detection start timing by the target proximity detection means. It has been done.

On the other hand, a fifth characteristic configuration of the monitoring device according to the present invention is the monitoring characteristic tag according to any one of the first to fourth characteristic configurations, wherein the monitoring tag is attached to the product to be monitored. The anti-theft tag described above, and the monitoring information is information on whether or not the anti-theft tag is attached to a product.

A sixth characteristic configuration of the monitoring device according to the present invention is the same as the fifth characteristic configuration, in which the transmitter and the object proximity detection means are placed in the vicinity of the cash register and the merchandise is placed at the time of checkout. It has been installed in the product placing plate for.

[0010]

According to the first characteristic configuration of the present invention, only while the monitoring target is detected to be close to the apparatus main body, in other words, only when the monitoring target approaches and it is necessary to actually obtain the monitoring information. Since the signal for monitoring information acquisition can be transmitted, it is possible to minimize the period of signal transmission that requires a considerably large amount of electric power as compared with object proximity detection, and in other cases, alarm means. It is possible to eliminate inadvertent actuation of the.

According to the second characteristic configuration of the present invention,
By operating the transmission state switching means, it is possible to appropriately switch between the transmission state of the minimum necessary monitoring information acquisition signal obtained by the first characteristic configuration and the continuous transmission state of the signal, so that the monitoring device It is possible to set the transmission state according to the installation conditions and installation environment.

Further, according to the third characteristic configuration of the present invention, monitoring is performed in a situation where a monitoring target approaches and it is necessary to actually obtain monitoring information, and moreover, monitoring is performed only for a minimum period necessary to obtain monitoring information. Since the information acquisition signal can be transmitted, it is possible to further reduce the signal transmission period in which the power consumption is large, and it is possible to obtain the monitoring information only from the target actually required, and in other situations, for example, , In the situation other than the proximity detection state of the monitoring target, such as when the lighting is turned off when the power of the monitoring device is forgotten to be turned off,
Alternatively, unnecessary signal transmission to an object other than the object for which the monitoring information is necessary can be eliminated.

According to the fourth characteristic constitution of the present invention,
By operating the transmission period switching means, the transmission state of the minimum necessary monitoring information acquisition signal during the target detection period obtained by the third characteristic configuration and the continuous transmission state of the signal during the target detection period are set. Since it is possible to switch appropriately, it is possible to set the transmission state according to the characteristics of the monitoring target, the installation conditions of the monitoring device, and the installation environment.

On the other hand, a fifth characteristic configuration of the present invention is a monitoring device applied for the prevention of theft of goods, and in particular, the device main body is installed near a cash register to prevent theft which is a monitoring tag at the time of billing. In the case of configuring to prevent forgetting to remove the tag, the monitoring information acquisition signal may be transmitted only while the product is actually brought near the cash register and a warning about forgetting to remove the tag is necessary, or Install a monitoring device near the cash register to prevent forgetting to remove the tag or install a monitoring device in the gate to prevent theft, and install a monitoring device near the cash register to warn forgetting to remove the tag. In this case, the transmission state of the monitoring information acquisition signal can be switched between continuous and product proximity detection according to the installation environment such as the change in the number of users depending on the time zone.

Further, according to the sixth characterizing feature of the present invention, the transmitter and the object proximity detecting means at the time of application as the tag forgetting warning in the product theft prevention monitoring system of the fifth characterizing feature. By incorporating the above into the product placing plate, the necessary configurations can be compactly put together.

[0016]

As a result, according to the first characteristic configuration, the transmission of the monitoring information acquisition signal can be minimized to save power and eliminate unnecessary alarms to reduce false recognition. Therefore, it is possible to provide a monitoring device that can reduce the running cost and ensure the monitoring function.

Further, according to the second characteristic constitution, by making it possible to switch the transmission state according to the difference in the installation situation or the like, the power saving and the reliable monitoring function by the first characteristic constitution can be realized. A feasible monitoring device has been made highly versatile.

Further, according to the third characteristic configuration, the transmission of the monitoring information acquisition signal during the object detection period is limited to the minimum period necessary to obtain the monitoring information, thereby further saving power. In addition, it is possible to eliminate unnecessary signal transmission in situations other than the proximity detection state of the monitoring target, and the monitoring information acquisition signal can be sent to another monitoring target during the detection period of one monitoring target. It is also possible to avoid confusion in the original monitoring information due to mixing of other monitoring information due to transmission, so it is possible to further reduce running costs and ensure the monitoring function. The equipment can now be provided.

Further, according to the fourth characteristic configuration, it is possible to switch the transmission period of the monitoring information acquisition signal during the detection of the monitoring object according to the characteristics of the monitoring object, the installation situation, etc. The monitoring device capable of realizing further power saving and a more reliable monitoring function by the third characteristic configuration can be made more versatile.

On the other hand, according to the fifth characteristic constitution, by applying it as a product for theft prevention, especially when it is installed near the cash register to warn that the antitheft tag attached to the product is forgotten. As a result, it is possible to provide an excellent monitoring device that is advantageous in terms of running cost and that does not cause discomfort to the customer because it can achieve lower power consumption and reduction of unnecessary alarm activation than before.

Further, according to the sixth characteristic construction, unnecessary construction can be compactly packaged, so that installation in the vicinity of the cash register for warning of forgetting to remove a tag in the surveillance system for theft prevention of goods can be achieved. We were able to provide a monitoring device with excellent installability that does not require the movement of large-scale furniture.

[0022]

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

As shown in FIG. 2, a first monitor body having a first transmitter 2 for transmitting a monitor information acquisition signal to an antitheft tag 1 attached to a product M at the entrance of a store. A pair of gates G incorporating 3 is provided, and a signal for monitoring information acquisition is also sent to the anti-theft tag 1 in the vicinity of the cash register R mounted on the counter C.
The device of the monitoring device of the present invention, which comprises a product placing plate 5 in which the transmitting device 4 is incorporated, and a power supply unit 7 having a transmitting control means 6 for controlling the transmission of the signal from the second transmitting device 4. A second monitoring body 8 which is a main body is installed to configure a monitoring system S for preventing theft of goods.

The monitoring system S is configured to prevent the goods M from being stolen as follows. That is, the anti-theft tag 1 as an example of the monitoring tag P is attached to each product M that is the monitoring target T in advance. Although not shown, the anti-theft tag 1 receives a monitor information acquisition signal from the first and second transmitters 2 and 4, and the receiver receives the monitor information acquisition signal. As a result, alarm means A that obtains monitoring information that the antitheft tag 1 is present and outputs an alarm sound, and a battery that supplies drive power to the receiving device and the alarm means A are incorporated. Normally, the clerk removes the anti-theft tag 1 from the product after performing the alarm canceling operation at the cash register R, but the anti-theft tag 1 is not charged at the cash register R. When the user tries to take out the product M with the tag attached to the outside of the store, the receiving device of the anti-theft tag 1 receives the monitoring information acquisition signal from the first monitoring device 3 incorporated in the gate G. The alarm means A emits an alarm sound to prevent theft.

The anti-theft tag 1 is attached to the product M by inserting a loop-shaped wire whose one end is fixed to the tag main body into the fabric of the product and then removably attaching to the tag main body or inserting it into the product. This is done by removably attaching the pin to the tag body. If the wire or pin is removed or cut without a proper operation, that is, an alarm release operation at the cash register, the above-mentioned alarm means A is activated as in the case of illegal removal. Is configured.

As described above, the anti-theft tag 1 is attached to the product M.
If you try to exit the gate G with the tag attached, an alarm sound will be heard.
If the user forgets to remove it, the alarm sound will sound even though he / she has purchased the product legally, and it will make the customer uncomfortable. Therefore, as described above, the same as the first monitoring body 3 incorporated in the gate G. The second monitoring body 8 having the above configuration is provided in the vicinity of the cash register R to prevent forgetting to remove the tag 1. That is, when the receiver of the anti-theft tag 1 receives the monitoring information acquisition signal from the second transmitter 4 incorporated in the product placing plate 5, the alarm means A of the anti-theft tag 1 is activated. In this way, the clerk is urged to remove the tag 1.

Next, the above-mentioned second installed near the cash register R
The monitoring body 8 will be further described.

As shown in FIG. 3, a hollow coil-shaped antenna 9 constituting a second transmitter 4 for transmitting a monitoring information acquisition signal is provided inside the product placing plate 5, and this antenna 9
Object proximity detecting means N for detecting whether or not there is a product on the product placing plate 5 located substantially in the center of the hollow part of the product.
Photoconductive cell 10 made of cadmium sulfide (CdS)
And L for displaying the transmission state from the antenna 9
An ED display device 11 is provided.

On the other hand, in the power supply unit 7 which is connected to the product placing plate 5 by a cord, the transmission control means 6 for controlling transmission of the surveillance information acquisition signal from the antenna 9 and the surveillance information acquisition signal. Power supply means for converting and supplying the power for transmission from a commercial power supply of 100V is provided. The transmission control means 6 allows transmission of the monitoring information acquisition signal from the antenna 9 only while the photoconductive cell 10 detects that the product M is on the product mounting plate 5. Configured. That is, the power consumption of the power consumption is increased so that the tag forgetting warning is issued only while the product M is brought to the cash register R for the bill and placed on the product placing plate 5, in other words, while actually required. By transmitting a large number of radio waves, it is possible to save electric power and reduce malfunctions such that the alarm means A is activated just by passing near the cash register R. Although not shown in FIG. 3, a switch operation is performed to send a signal for monitoring information acquisition from the antenna 9 only during the product proximity detection by the photoconductive cell 10 as described above, and a state where the signal is always sent. It is configured so that it can be switched to.

Next, the internal circuit of the above-mentioned second monitoring main body 8 and its operation will be described. FIG. 1 shows an overall block diagram.

The oscillator circuit 12 is the number from the crystal oscillator 13.
The reference frequency of MHz is oscillated, and the frequency dividing circuit 14 divides the reference frequency by 182 and outputs it to the power amplifier circuit 15 as a clock signal of several tens KHz. The power amplifier circuit 15 amplifies this clock signal to provide the resonance circuit 1 including the antenna 9.
6 is output as a coil drive current to the antenna 9
It is configured to oscillate as a monitoring information acquisition signal at a resonance frequency of KHz. Then, in the second monitoring device 8, by outputting a radio wave having a relatively low frequency of several tens KHz as the monitoring information acquisition signal as described above,
The influence of disturbances such as electromagnetic noise is reduced.

On the other hand, the resonance frequency is several tens KHz and is in a low frequency range, and the inductance of the coil may change and the resonance frequency may change or the output may change depending on the installation situation or installation environment of the second monitoring body 8. Therefore, the power amplification circuit 15 is provided with the output level adjusting unit 17 that constitutes the transmission output adjusting means L so that the monitoring information acquisition signal can be transmitted with a stable frequency and a stable output at all times. , The resonance frequency adjusting means F in the resonance circuit 16
There is provided a resonance frequency adjusting unit 18 constituting the above. Further, in order to monitor the oscillation output, a current monitor circuit 19 for monitoring the coil drive current from the power amplification circuit 15 to the resonance circuit 16 is provided, and the monitoring result by the current monitor circuit 19 is placed on the product placement described above. The LED display device 11 provided on the plate 5 is used for displaying.

Further, in the frequency dividing circuit 14, the photoconductive cell 1 is connected via a switch 20 which is a transmission state switching means.
The detection signal from 0 to the product detection circuit 21 is input, and in the ON state of the switch 20, the frequency dividing circuit 14 to the power amplification circuit 15 only in accordance with the detection signal from the photoconductive cell 10 during the proximity detection of the product M. Input of a clock signal to the power amplifier circuit 15 is allowed, and the clock signal is always input from the frequency dividing circuit 14 to the power amplifier circuit 15 when the switch 20 is turned off. Therefore, the monitoring information is acquired from the antenna 9 only during the product proximity detection. It is configured to emit a signal for use.

FIG. 4 shows a specific configuration of the oscillator circuit 12 and the frequency divider circuit 14 described above. The frequency divider circuit 14 divides the reference frequency by using the 12-bit counter 22 and the NAND circuit 23. However, the output of the 12-bit counter 22 is divided between the 12-bit counter 22 and the NAND circuit 23 in units of 1 bit. A shift switch 24 for shifting is provided. The shift switch 24 changes the frequency division ratio by changing the output timing of the reset signal to the NAND circuit 23, whereby the resonance frequency of the resonance circuit 16 is changed by the resonance frequency adjusting unit 18. It is constructed so that it can be adjusted in a range larger than the adjustment range. That is, the shift switch 24 constitutes the resonance frequency adjusting means F together with the resonance frequency adjusting section 18.

FIG. 5 shows a specific configuration of the power amplification circuit 15 and the resonance circuit 16 described above. In the power amplification circuit 15, the output level switching unit 17 is configured by interposing a plurality of resistors, which are circuit elements, in parallel in a portion that divides the input clock signal, and each of the dip switches SW1 to SW1.
The coil drive current is changed to 10 by changing the voltage division ratio by changing the combination of the plurality of resistors by turning on and off SW4.
The range is adjusted to be 0% to 40%.
Further, in the resonance circuit 16, the resonance frequency adjusting unit 18
Is configured by connecting a plurality of capacitors, which are circuit elements, in parallel, and then interposing in series with the antenna 9.
By changing the combination of these multiple capacitors by changing the combination of each DIP switch SW5 to SW8 to change the combined capacitance, the resonance frequency is about ± 1 with respect to several tens KHz.
It is possible to change and adjust to the range of%.

FIG. 6 shows the above-mentioned current monitor circuit 19,
A specific configuration with a product detection circuit 21 that detects the presence or absence of a product M using the output of the photoconductive cell 10 is shown.

The current monitor circuit 19 is constructed so as to take in and check the output from the power amplification circuit 15, and monitor the power supply state by using the red LED 11a and the green LED 11b constituting the display device 11. I can do it. That is, in normal output, green L
Only the ED 11b is turned on, and if the output is large and there is a risk of damage to the circuit element due to heat generation, a red LED
11a is turned on. Therefore, when adjusting the transmission output, when the green LED 11b does not light up, that is, when the output is small and it is difficult to reach the radio wave to the anti-theft tag 1, the output level switching unit 17 is operated to prevent the red LED 11a from lighting up. You can increase the output with.

In the input to the product detection circuit 21, the photoconductive cell 10 has a low resistance value when the input light is bright because there is no product M on the product mounting plate 5, and the product M is the product mounting plate. The resistance value becomes higher when the input light is placed on the surface 5 and becomes dark, and the NA value is increased according to the resistance value.
An "H" level signal is output to the ND circuit 23 when the resistance is high and an "L" level signal is output when the resistance is low.

[Second Embodiment] In the embodiment shown in FIGS. 7 to 13, the overall structure of the surveillance system S for preventing theft of goods is the same as that of the previous embodiment, but the details are slightly changed. In addition.

First, the changed portion of the internal circuit of the second monitoring body 8 will be described. FIG. 7 shows the entire block.

The oscillation frequency dividing circuit 30 divides the reference frequency of several MHz from the built-in crystal oscillator to divide the power into the power amplifier circuit 15.
Output to. The control signal from the product detection circuit 21 for controlling the input of the clock signal for exciting and transmitting the monitoring information acquisition signal from the oscillation frequency dividing circuit 30 to the power amplification circuit 15 is an example of the transmission period limiting means I. It is configured so as to be input to the oscillation frequency dividing circuit 30 via the monostable multivibrator circuit 31. The details of this configuration will be described later. A buzzer circuit 32 is provided as a means for notifying the user of the output of the monitor information acquisition signal by using the output signals from the multivibrator circuit 31 and the oscillation frequency dividing circuit 30. Further, there is provided a level meter 33 for displaying the transmission output of the monitoring information acquisition signal using LEDs in five stages.

On the other hand, as shown in FIG. 8 and FIG.
In the product placing plate 5 placed in the vicinity, the antenna 9 of the resonance circuit 16 is positioned on the product placing side of the ferrite sheet 35 together with the ferrite sheet 35, which is an example of a plate-shaped magnetic electromagnetic wave absorbing material, and both of them are placed. Cushion material 3 between
4 is incorporated. This is the product placement plate 5
When the desk or the counter on which is placed is made of metal, it is intended to prevent the transmission of the monitoring information acquisition signal from becoming unstable due to the influence of the metal. That is, the resonance circuit 1
When the antenna 9 of 6 is energized, a magnetic field that causes an eddy current is generated inside a metal desk or counter. By absorbing this magnetic field with the ferrite sheet 35, when such an eddy current occurs, On the contrary, it is possible to avoid the adverse effect of the transmission from the antenna 9 due to the generated magnetic field. Incidentally, the ferrite sheet 35
Introducing a part of the results of the experiment on the change of the inductance value of the coil configuring the antenna 9 depending on the presence or absence of the above, the inductance value of the test piece only by the coil is 0.903 m in the normal state at the measurement frequency of 22 KHz.
What is H is 0.25 by putting an aluminum plate under it.
At 3 mH, the change in the inductance value of 0.650 mH was observed, whereas as shown in FIG. 8, the inductance value of the coil constituting the antenna 9 incorporated with the ferrite sheet 35 was 1 in the normal state. .297
What is mH is 1.1 by putting an aluminum plate under it.
At 05 mH, the change in the inductance value of 0.192 mH was sufficient, and it was clear that the coil transmission state was stabilized by incorporating the ferrite sheet 35 together.

As shown in FIG. 9, eight ferrite small plate pieces 35a are combined to form a ferrite sheet 35 which is an example of a plate-shaped magnetic electromagnetic wave absorbing material. Further, ribs 35b are interposed between the small pieces 35a of ferrite to improve the strength and prevent cracks and the like from occurring.

Next, the input control of the clock signal from the oscillation frequency dividing circuit 30 to the power amplification circuit 15 will be further described. As shown in FIG. 10, in the product detection circuit 21, a signal from a bridge circuit incorporating the product placement detection photoconductive cell 10 provided on the product placement plate 5 is prevented from malfunctioning due to a slight change in light. It is input to the multivibrator circuit 31 via a comparator 36 in which a feedback resistor R1 having a hysteresis characteristic is connected in parallel. The output from the multivibrator circuit 31 is supplied to the switch 3
It is inputted to the oscillation frequency dividing circuit 30 via 7, and the oscillation frequency dividing circuit is input only for a predetermined time from the timing when the product is placed on the product placing plate 5 and the resistance of the photoconductive cell 10 is changed. The circuit 30 is configured to allow the clock signal to be emitted. As a result, only when the product M is placed on the product mounting plate 5 and the monitoring information is actually needed, the monitoring information acquisition signal is transmitted for the minimum required period to save power and to prevent malfunction. The occurrence has been reduced. That is, in the configuration of the previous embodiment, since the monitoring information acquisition signal is always transmitted while the resistance value of the photoconductive cell 10 is changing, for example, when the power of the monitoring system S is forgotten to be turned off, When the business is closed, the information acquisition signal is always transmitted even when there is no product M on the product placing plate 5 with the illumination off at night, or the product is not available during the business. Even if M is placed on the product placement plate 5 and the anti-theft tag 1 is removed, if a person carrying the product M with the anti-theft tag 1 still passes by near it, forget to remove the tag. Therefore, the warning means A may be activated. Therefore, in the present embodiment, the monitoring information acquisition signal is transmitted only for a predetermined time after the detection of the product placement, so that the above inconvenience can be avoided. In addition,
The predetermined time may be several seconds, and the period can be changed. In addition, by turning on / off the switch 37, which is an example of the transmission period switching means C, a state in which the transmission of the information acquisition signal is allowed only for a predetermined period after the above-described product placement detection, and the product M is placed on the product placement plate 5. It is configured such that it can be switched to a state in which an information acquisition signal is always transmitted while it is present in.

Then, the multivibrator circuit 31
Output from the oscillation frequency dividing circuit 30 via the switch 38.
It is input to the buzzer control circuit 39 that constitutes the buzzer circuit 32 together with the output from. This buzzer control circuit 39
Is configured to ring the buzzer 40 at the timing at which the information acquisition signal is transmitted in a pulsed manner by the operation of the multivibrator circuit 31 to alert the user.
The switch 38 is turned on / off so that the buzzer 40 can be turned on or off. Further, the switch 38 can be replaced with a variable resistor and configured to adjust the volume of the buzzer 40.

11 and 12 show specific examples of the internal circuit of the second monitoring main body 8. Note that the terminal symbols a to e in the figure are terminal symbols of sockets for connection with the internal circuit of the product placing plate 5 shown in FIG.

In the oscillation frequency dividing circuit 30 shown in FIG. 11, several MHz oscillated by the crystal oscillator 13 and the inverter.
The 14-bit counter 40 divides the reference frequency of (1) to several KHz and sends it to the power amplification circuit 15. According to this configuration, in the configuration in which the buffer circuit is combined as in the first embodiment described above, the oscillation can be stabilized when the oscillation frequency may become unstable due to variations in the delay time of the elements or the like.

In the power amplifier circuit 15, a variable resistor R2 for changing the input rectangular wave voltage to the driver 41 is provided as the output level switching unit 17 constituting the transmission output adjusting means L. Further, as the resonance frequency adjusting unit 18 forming the resonance frequency adjusting means F for the resonance circuit 16, four kinds of capacitors and combinations thereof are switched to form the resonance circuit 1.
A rotary dip switch 42 for changing the inductance of No. 6 is provided. In addition, in FIG.
3 is a one-shot multivibrator which is a main component of the multivibrator circuit 31, and in the buzzer control circuit 39, 44 is a switching transistor.
Reference numeral 45 is a transistor for changing the tone color of the buzzer 40 using a signal obtained by dividing the reference frequency by the 14-bit counter 40.

FIG. 12 shows the current monitor circuit 19 and the level meter 33. The level meter 33 uses the signal input from the current monitor circuit 19, and the driver 46 according to the magnitude of the output from the power amplification circuit 15.
The five LEDs 47 to 51 controlled by are configured to perform five-level display. Specifically, the four LEDs 47 to 50 from the low output side are green, and the one on the high output side is
The two LEDs 51 are red to warn of an excessive output state. Further, the LED 52 that lights up at the same output level as the LED 47 for displaying the minimum output is incorporated in the internal circuit of the product placing plate 5 shown in FIG. 13 and is for operation monitoring. LED52 changes connection, power supply ON /
It may be used as an OFF display.

[Other Embodiment] Another embodiment of the present invention will be described below.

<1> In the above two embodiments, the monitoring device according to the present invention is applied to a monitoring system for preventing theft of goods, but other than that, the following application is also possible. .

<1-1> The monitoring device according to the present invention is applied to a non-contact automatic ticket gate system. That is, in this case,
The surveillance target T is a passenger, and the surveillance tag P carried by the passenger
Is a commuter pass or boarding ticket consisting of an IC card, etc. If the device main body provided with a transmitting device for sending a signal for monitoring information acquisition to the commuter ticket or boarding ticket is provided at the gate for the reissue ticket gate Good. In such an automatic ticket gate system, commuter passes such as IC cards and boarding section information, ticket validity information, and presence / absence information of such commuter tickets and tickets are monitoring information, and are used as gate information for ticket gates. The IC card or the like which has received the monitoring information acquisition signal transmitted from the transmitting device transmits the above-mentioned monitoring information toward the device body in response to the reception thereof, and the device body receives the monitoring information receiving device. An alarm means is provided, and based on the obtained monitoring information, for example, when a passenger does not have a ticket, a boarding section is different, or the expiration date has passed, an alarm such as a chime is issued. Can be configured as.

<1-2> The monitoring device according to the present invention is applied to a parking monitoring system. In this case, the monitoring target T is an automobile, and the surveillance tag P carried by the automobile is a parking card such as an IC card issued with permission to park. The device body provided with a transmission device for transmitting a monitoring information acquisition signal to the parking card is embedded in the entrance gate of the parking lot or in the parking space for one vehicle, or has a meter or the like in the vicinity thereof. It may be provided on a pole or the like that is erected for installation. In such a parking monitoring system, the contract period information, the temporary parking permission information, etc. of the parking card and the presence / absence information of the parking card are the monitoring information, and the monitoring information acquisition signal transmitted from the transmitting device is received. Upon receipt of the parking card, the parking card transmits the above-mentioned monitoring information to the main body of the apparatus, and the main body of the apparatus is provided with a monitoring information receiving device and an alarm means, and the obtained monitoring information Based on this, for example, when the user does not have a parking card or has passed the contract period, an alarm such as a chime may be issued.

<2> In the above two embodiments, the monitoring device 8 of the present invention is used in a monitoring system for preventing theft of goods.
Although the one applied as the second monitoring device, such as used for a tag forgetting warning, has been described, the first used for a theft warning in the same monitoring system instead of or in addition to that.
The monitoring device 3 may be applied.

<3> In the above embodiment, the alarm means A is provided in the surveillance tag P which is implemented as the anti-theft tag 1. However, other than that, the following may be implemented. It is possible.

<3-1> The device body 8 provided with the transmitting device 4 is provided with the alarm means A, and the monitoring tag P side receives the monitoring information acquisition signal from the transmitting device 4 to receive the alarm information. A response device for transmitting a response signal is provided in advance, and an alarm is issued on the device body 8 side.

<3-2> The alarm means A is provided on both the apparatus main body 8 and the surveillance tag P, and the present invention is applied to, for example, a surveillance system for preventing theft of goods as in the previous embodiment. In this case, in the vicinity of the transmitting device 4, that is, when the product M is brought near the cash register R or at the gate G of the entrance / exit, the alarm means A on the device main body 8 side is activated, while the above description is given. As described above, when the tag 1 is illegally removed from the product M, the alarm means A on the monitoring tag P side is activated.

<4> In the previous embodiment, the object proximity detecting means N provided with the photoconductive cell 10 made of cadmium sulfide (CdS) has been described. However, instead of this, a reflection type or transmission type optical sensor. , Infrared sensor, surveillance tag P
Including various types of non-contact type sensors such as a sensor for detecting a metal that constitutes a battery in the inside, a sensor for detecting a change in electrostatic capacity, and the like, for example, in the case of being incorporated in the product mounting table 5, A sensor other than the non-contact type sensor such as a sensor for detecting the weight or a micro switch operated when the product M is placed may be provided.

<5> In the above embodiment, the transmitter 4 and the object proximity detecting means N are incorporated in the product placing plate 5, and the transmission control means 6 and the like are incorporated in the power supply unit 7 in order to prevent forgetting to remove the tag. As described above, instead of them, all of these configurations are integrally incorporated in the product placing plate 5, or the product placing plate 5 is installed next to the cash register R without providing them. All the configurations may be integrated, or all of the configurations may be incorporated in the register R itself. Further, in the previous embodiment, the commercial power source of 100 V was used as the power source, but instead of this, electric power may be obtained from the built-in battery.

<6> In the above embodiment, by switching the switch 20 which is the transmission state switching means, the state in which the transmission of the monitoring information acquisition signal is permitted only during the proximity detection of the target and the state in which it is always permitted. Although the switchable configuration has been described, in order to simplify the configuration, the switch 20 is omitted and the transmission of the monitoring information acquisition signal is always permitted only during the proximity detection of the target. You may

<7> As the alarm means A, a structure for emitting an alarm light may be adopted instead of or in addition to the structure for emitting an alarm sound. Further, the alarm sound may be a continuous sound or an intermittent sound. Further, any of synthetic voices or the like may be used or combined. For example, in the case of a monitoring system for preventing theft of goods, the warning for theft at the entrance gate and the warning for forgetting to remove the tag at the cash register are different. A form of alarm may be issued.

<8> In the claims, reference numerals are given for convenience of comparison with the drawings, but the present invention is not limited to the structures of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a monitoring system.

FIG. 2 is a schematic diagram of a monitoring device.

FIG. 3 is a block diagram of a monitoring device according to the first embodiment.

FIG. 4 is a circuit diagram of an oscillator circuit and a frequency divider circuit according to the first embodiment.

FIG. 5 is a circuit diagram of a power amplification circuit and a resonance circuit according to the first embodiment.

FIG. 6 is a circuit diagram of a current monitor circuit and a product detection circuit according to the first embodiment.

FIG. 7 is a block diagram of a monitoring device according to a second embodiment.

FIG. 8 is a sectional view of a product placing plate according to a second embodiment.

FIG. 9 is a plan view of the inside of the product placing plate according to the second embodiment.

FIG. 10 is a block diagram including a product detection circuit and a buzzer circuit according to a second embodiment.

FIG. 11 is an internal circuit diagram of the monitoring device according to the second embodiment.

FIG. 12 is an internal circuit diagram of the monitoring device according to the second embodiment.

FIG. 13 is an internal circuit diagram of the product placing plate of the second embodiment.

[Explanation of symbols]

 1 Anti-theft tag 4 Transmitting device 5 Product placement plate 6 Transmission control means 8 Device body 20 Transmission state switching means T Monitoring target P Monitoring tag A Warning means C Transmission period switching means I Transmission period limiting means N Target proximity detection means M Product R cash register

Claims (6)

[Claims] 1. A surveillance tag (P) carried by a surveillance target (T)
Transmitting device (4) that sends a signal for monitoring information acquisition to
Is provided in the device body (8), and an alarm is issued to at least one of the device body (8) and the monitoring tag (P) based on the monitoring information obtained in response to the transmission of the monitoring information acquisition signal. In a monitoring device provided with an alarm means (A) for issuing, an object proximity detection means (N) for detecting the proximity of a monitoring object (T) is provided in the device body (8), and the object proximity detection means ( A monitoring device provided with transmission control means (6) for permitting the transmission of the monitoring information acquisition signal from the transmission device (4) only during the object proximity detection by N). 2. A state in which the transmission control means (6) permits transmission of a monitoring information acquisition signal from the transmission device (4) only during detection of a target proximity by the target proximity detection means (N), The monitoring device according to claim 1, further comprising a transmission state switching means (20) for switching to a state in which the monitoring information acquisition signal is constantly transmitted from the transmission device (4). 3. The transmission control means (6) permits transmission of a monitoring information acquisition signal from the transmission device (4) only for a predetermined period from the target proximity detection start timing of the target proximity detection means (N). Transmission period control means (I)
The monitoring device according to claim 1 or 2, further comprising: 4. A state in which the transmission control means (6) always transmits a monitoring information acquisition signal from the transmission device (4) during the target proximity detection by the target proximity detection means (N).
A transmission period switching means (C) is provided for switching to a state in which the transmission of the monitoring information acquisition signal from the transmission device (4) is allowed only for a predetermined period from the target proximity detection start timing of the target proximity detection means (N). The monitoring device according to claim 3, which is a device. 5. The surveillance tag (P) is a theft prevention tag (1) attached to a product (M) which is a surveillance target (T), and the surveillance information includes the antitheft protection for the product (M). The monitoring device according to any one of claims 1 to 4, which is information on whether or not a tag (1) for use is attached. 6. The product placing plate (5) for placing the product (M) when the transmitter (4) and the object proximity detecting means (N) are placed in the vicinity of the cash register (R) at the time of checkout. 6. The monitoring device according to claim 5, which is incorporated in