JPH0512576A - Burglary preventing machine - Google Patents

Abstract

PURPOSE:To surely prevent a burglary without requiring the radiation of electromagnetic waves and the installation of another specific equipment. CONSTITUTION:This burglary preventing machine 1 is provided with an optical sensor 5a, an oscillation sensor 13, an auxiliary control circuit 30, a control circuit 31, and an alarm driving circuit 32. The circuit 30 supplies power for a fixed period only when the sensor 13 detects mechanical oscillation, and holds the power supply at the time of inputting an power supply ON signal. At the time of judging that an electric signal from the sensor 5a is a frequency band other than a prescribed frequency band when power is supplied from the circuit 30, the circuit 31 outputs an alarm driving signal to the circuit 32 and outputs the power supply ON signal to the circuit 30. When the alarm driving signal is inputted to the circuit 32, the circuit 32 drives an electronic buzzer 15 to be an alarm to generate an alarm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antitheft machine for preventing theft of goods and the like, and more particularly to an antitheft machine capable of surely preventing theft without installing special equipment.

[0002]

2. Description of the Related Art In a conventional anti-theft system, an anti-theft device (hereinafter abbreviated as "tag") is attached to each product displayed in a product exhibition space and the product is taken out of the product exhibition space. Generally, the tag or fixed security equipment is configured to sound an alarm.

As such conventional antitheft systems, there are roughly three types of systems.

The anti-theft system adopting the first method comprises a tag attached to each product and a fixed crime prevention equipment. This fixed crime prevention equipment is capable of constantly emitting strong electromagnetic waves to the gate part of the product exhibition hall, and when the tag of only the resonator that doubles as an antenna passes through the gate part, the resonator is turned on. Since the reflected wave is reflected from the tag by being excited, an alarm is issued when the reflected wave is received by the fixed crime prevention equipment. This allows
Product theft can be prevented.

The antitheft system adopting the second method is a resonator attached to each product and also serving as an antenna,
It consists of a receiver that is connected to it, a tag that incorporates a sound generator that issues an alarm in response to instructions from this receiver, and a radio wave exciter that constantly radiates strong radio waves near the gate of the product exhibition space. In this anti-theft system, when a product is passed through a gate, an electromagnetic wave from the radio wave exciter excites the resonator, so that a sound generator of the tag issues an alarm. Thereby, theft of the product can be prevented.

The antitheft system adopting the third method is a radio wave that emits a strong radio wave near the gate of a product exhibition hall and a tag having a resonator also serving as an antenna and a transceiver connected to the resonator. It is configured to include an exciter and a radio wave detector that searches for radio waves emitted from the tag. According to this anti-theft system, when the product is passed through the gate, the radio wave from the radio wave exciter causes the resonator of the tag to resonate, which activates the receiver and operates the transmitter. Will be emitted, and the radio waves from this tag will be searched by the radio wave detector. As a result, it is possible to prevent the product from being taken out without permission.

[0007]

According to the anti-theft system of each of the above methods, the radio wave exciter installed near the gate needs to emit a strong radio wave in order to resonate the resonator of the tag. As a result of the revision of the Radio Law, there is a drawback that it does not meet that standard.

Further, according to the antitheft system of each of the above methods, the tag needs to be provided with an antenna which also serves as a resonator in order to receive an electromagnetic wave, and the antenna cannot be miniaturized. Has the drawback that it cannot be miniaturized.

The present invention has been made to solve the above-mentioned drawbacks, and it is an object of the present invention to provide an antitheft machine which can prevent theft without requiring the emission of electromagnetic waves and without any special equipment. To aim.

[0010]

In order to achieve the above object, an anti-theft device according to the present invention comprises an optical sensor for converting light and dark of light into an electric signal and a vibration sensor for converting mechanical vibration into an electric signal. An auxiliary control circuit that takes in an electric signal from the vibration sensor and supplies electric power for a certain time only when the vibration sensor detects vibration, and an electric signal from the optical sensor when the electric power is supplied from the auxiliary control circuit. Comprises a control circuit that outputs an alarm drive signal when the frequency is outside a predetermined frequency band, and an alarm drive circuit that drives an alarm device by the alarm drive signal from the control circuit to generate an alarm. Is.

[0011]

The anti-theft device of the present invention pays attention to the fact that, in the case of theft, the user must carry the product and take it out of the doorway, and when the product is stolen, the vibration is generated to move the product. In addition, for example, from the state of being illuminated with pulsed illumination light related to the commercial power frequency, a dark state is detected by putting it in a bag, continuous light is detected, or light pulses of other frequencies are detected. Then, an alarm is issued when the optical pulse related to the frequency is no longer detected. This can prevent theft.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 9 are views for explaining an embodiment of the present invention. FIG. 1 is a perspective view showing an application example of the anti-theft device of the present invention.

In FIG. 1, a clear case 2 is fixed on the anti-theft device 1, and a product 3 such as a compact disc (CD) can be stored in the clear case 2. Inside the clear case 2 at the upper part of the anti-theft device 1 in the figure, a micro switch 4
The operation part of is exposed. The anti-theft device 1 does not give an alarm while the operation part of the micro switch 4 is being pressed by the product 3, and conversely, when the product 3 is pulled out from the clear case 2, the anti-theft device 1 is in the anti-theft operation. At some point an alarm will be issued. Optical sensors 5a and 5b are provided on the side surface of the anti-theft device 1. Although not shown, a battery operation hole for moving the battery for resetting is provided on the side surface opposite to the optical sensors 5a, 5b.

FIG. 2 shows the arrangement of the main parts constituting the anti-theft device. An optical sensor 5a is provided on the upper short side surface 7 of the rectangular case 6 shown in the figure, and a micro sensor is provided on the long side surface 8. The operation part of the switch 4 is exposed.
The button battery 1 is provided on a side surface 9 opposite to the short side surface 7.
An operation hole 12 is provided for inserting 0 into the battery holder 11 as shown by an arrow Y in the drawing or detaching it as shown by an arrow Z in the drawing. The button battery 10 is attached to the battery holder 1
When inserted in 1, the anti-theft device 1 is activated. A vibration sensor 13 is provided near the battery holder 11. An integrated circuit (IC) 14 that processes the operation is provided above the vibration sensor 13, and an electronic buzzer 15 for alarm is provided.

FIG. 3 shows a detailed structure of the vibration sensor 13 used in the anti-theft device 1. The vibration sensor 13 includes a movable body 16 that moves according to vibration.
And a detection body 17 for detecting the movement of the movable body 16. The movable body 16 has one end of the rod-shaped body 18 rotatably attached to a shaft 20 planted in a base 19, a conductive member 21 is provided at the other end of the rod-shaped body 18, and the rod-shaped body 18 is a coil spring. It is configured to return to a fixed position at 22. Further, in the detection body 17, a stopper 23 formed by a conductive member in a U shape is fixed on an insulating plate 24 on a base 19, and the conductive member 21 is placed in a U-shaped groove of the stopper 23. It fits loosely and the stopper 23
The standing pieces 25, 25 are placed at the turning radius position of the conductive member 21 so that the stopper and the detection electrode act. Further, in the vibration sensor 13, the conductive member 21 of the rod-shaped body 18 has the standing pieces 25, 25 of the stopper 23.
The vibration can be electrically detected by touching the.

FIG. 4 is a block diagram showing a circuit example of the anti-theft device 1. Anti-theft device 1 shown in FIG.
Is composed of a micro switch 4, an optical sensor 5, a vibration sensor 13, an auxiliary control circuit 30, a control circuit 31, an alarm drive circuit 32, and an electronic buzzer 15. The optical sensor 5a has a structure capable of detecting light and darkness of light and converting it into an electric signal, for example, a photodiode,
Phototransistor etc. are mentioned. The optical sensor 5b has a structure capable of detecting the brightness of light and converting it into an electric signal, and examples thereof include a phototransistor and a solar cell. The vibration sensor 6 has a structure capable of detecting vibration and converting it into an electric signal, and uses, for example, a structure shown in FIG. The vibration sensor 13 may have any configuration as long as it can detect some electric signal in response to vibration by a mercury switch, a reed switch, or another switch. The micro switch 4 can electrically detect that the product 3 is pulled out from the clear case 2. The auxiliary control circuit 30 uses the vibration sensor 1 when the light sensor 5b detects light.
When 3 detects a vibration, for example, the power is turned on for a fixed time of about 15 seconds after the vibration is no longer detected, and the power is supplied to the control circuit 31. Control circuit 31
Outputs a power-on signal for driving the alarm drive circuit 32 to cause the electronic buzzer 15 to ring, and for continuously supplying power to the auxiliary control circuit 30 when no light pulse of 100 Hz is detected, for example. To do. Further, when the micro switch 4 detects that the product 3 has been pulled out from the clear case 2, the alarm drive circuit 32 operates immediately and sounds the electronic buzzer 15 to issue an alarm. Note that the control circuit 31 and the alarm drive circuit 32 operate the button battery 10 from the operation hole 12 to turn off the power, or the button battery 1 once the electronic buzzer 15 sounds.
It keeps ringing until the capacity of 0 ends.

FIG. 5 and FIG. 6 show specific examples of the structure of the anti-theft device. The symbol M shown in FIG. 5 is electrically connected to the symbol M shown in FIG. This anti-theft machine 1
Is an auxiliary control circuit 30 that outputs electric power when the vibration sensor 13 detects a vibration while the vibration sensor 13 and the optical sensor 5b detect light, and an auxiliary control circuit 30.
It operates when there is power supply from the optical sensor 5
The electronic buzzer 1 that takes in a control circuit 31 that forms an alarm drive signal and a power-on signal when a frequency component other than 100 Hz is detected from the detection signal from a, and an alarm drive signal from the control circuit 31 or a signal of the microswitch 4
5 and an alarm drive circuit 32 for driving 5.

The auxiliary control circuit 30 includes resistors R ₀ , R ₁ and
It includes a capacitor C ₀ , diodes D ₀ and D ₁ , and inverter circuits IV ₀ and IV ₁ . Auxiliary control circuit 3
0, a parallel circuit of the resistor R ₀ , the optical sensor 5b, the vibration sensor 13, the resistor R ₁ and the capacitor C ₀ is connected in series between the power source and the ground.
When the vibration sensor 13 detects vibration while b is detecting light, electric charge is stored in the capacitor C ₀ . When a fixed charge is accumulated in the capacitor C ₀ , electric power is output through the diode D ₀ and the inverter circuits IV ₀ and IV ₁ for a fixed time (for example, 15 seconds). The power-on signal is supplied to the input terminal of the inverter circuit IV ₀ via the diode D ₁ .

The control circuit 31 includes a resistor R ₃ to R _7, a capacitor C ₁ -C _5, an operational amplifier OP _1, the transistor T _r1, an inverter circuit IV _2, IV _3, a NAND circuit ND _1, Noah The circuits NR ₁ and NR ₂ are provided.
In the control circuit 31, the power supply current from the auxiliary control circuit 30 flows to the ground via the optical sensor 5a, the resistor R ₂ and the diode D ₂ . As a result, the optical sensor 5a
An operational amplifier OP that detects an optical pulse and uses this optical pulse detection signal to form a comparator via a capacitor C _1.
Input to one input terminal of ₁ . The reference voltage is input from the diode D ₂ to the other input terminal of the operational amplifier OP ₁ . The pulse signal amplified by the operational amplifier OP ₁ is differentiated by the capacitor C ₂ and amplified by the transistor T _r1 . Pulse signal amplified by the transistor T _r1 is converted into sawtooth wave by the resistor R ₅ and capacitor C ₃ at the collector of the transistor T _r1. The sawtooth wave is converted into a pulse signal having a constant width by the threshold level of the inverter circuit IV ₂ and output. This pulse output has a resistance R ₆ and a capacitor C ₄
The low-pass filter converts the pulse frequency signal into a high-low level signal. This level high / low signal is input to the input terminal of one of the inverter circuit IV ₃ , the NAND circuit ND ₁ and the NOR circuit NR ₂ . The output signal of the inverter circuit IV ₃ is a resistor R ₇ and a capacitor C.
It is input to the other input terminal of the NAND circuit ND ₁ via ₅ . The output of the NAND circuit ND ₁ is supplied to one input terminal of the NOR circuit NR ₁ . NOR circuit NR ₁ , NR ₂
Is an RS flip-flop, and a NOR circuit N
The outputs of R ₁ and NR ₂ and the other input terminal are connected to each other in a stroking manner. The output of the NOR circuit NR ₁ is supplied to the alarm drive circuit 32. The output of the NOR circuit NR ₂ is
The diode D ₀ of the auxiliary control circuit 30 is used as a power-on signal.
It is connected to the.

The alarm driving circuit 32, the resistor R ₈ to R _10, capacitors C _6, C _7, diode D _3, D _4, the NAND circuit ND _2, the inverter circuit IV _4, and a transistor T _r2. One input terminal of the NAND circuit ND ₂
The output of the NOR circuit NR ₁ is directly connected to the microswitch 4 via the diode D ₃ . Further, the NAND circuit ND ₂ , the inverter circuit IV ₄ , the capacitor C _6, and the resistors R ₈ and R ₉ constitute an oscillation circuit.
When one input terminal of the NAND circuit ND ₂ is “1”, the oscillation circuit does not operate, and when it is “0”, the oscillation circuit operates. The output of this oscillation circuit is input to the base of the transistor T _r2 to cause the electronic buzzer 15 to ring and to modulate it with the oscillation frequency.

FIG. 7 shows a state in which the anti-theft device 1 according to the present embodiment is used in a store, and a display shelf 41 is placed inside the building 40. A large number of anti-theft devices 1 that store the products 3 are arranged in the display shelf 41. These products 3 are illuminated by a fluorescent lamp 42 provided on the ceiling or the like of the building 40. The fluorescent lamp 42 is driven to be lit by AC power of commercial frequency. Reference numeral 43 is an entrance to the building 40 for customers to enter and exit.

FIG. 8 shows the plane of the store shown in FIG. In FIG. 8, an area illuminated by the fluorescent lamp 42 installed in the store is shown, and an area 49 is illuminated by the general fluorescent lamp 42 with the light modulated in the cycle of the commercial frequency. When exiting the area 49 in the store, white light of an ordinary incandescent lamp and unmodulated light of sunlight are emitted. In addition, at night, since the number of lighting devices is small outside the area 49 in the store, the brightness is darker than that in the store.

FIG. 9 is a time chart showing the operation of the anti-theft device 1. 10A to 10E are diagrams showing the waveforms of signals at points indicated by reference numerals (A) to (E) in the circuit diagram of FIG. 5, where the horizontal axis represents time and the vertical axis represents voltage. Show.

The operation of the anti-theft device 1 thus constructed will be described with reference to FIGS. 1 to 10.

<When the display shelf is stationary>

First, it is assumed that the anti-theft device 1 is placed on the display shelf 41, is in a stationary state, and is illuminated by the fluorescent lamp 42. Then, in the period T ₁ of FIG. 9, the optical sensor 5b detects light (see FIG.
(1)), since the vibration sensor 13 is off (FIG. 9 (2)), the input of the inverter circuit IV _{0 in} the preceding stage becomes “0” (FIG. 9 (3)), and the inverter circuit I in the subsequent stage.
The output of V ₁ becomes “0” ((4) in FIG. 9), and the power is the frontmost circuit portion of the control circuit 31 (the operational amplifier OP, the optical sensor 5).
b)) is not supplied. Accordingly, the control circuit 31, the collector is "1" and transistor T _r1, the output of the inverter circuit IV ₂ since the "0" (FIG. 9
(6)), "0" is output as the output of the NAND circuit ND ₁ (FIG. 9 (7)). As a result, the input of the NOR circuit NR ₁ becomes “0” (FIG. 9 (7)), and the input of the NOR circuit NR ₂ is also “0” (FIG. 9 (6)). In this case, the characteristics of the NOR circuits NR ₁ and NR ₂ are selected so that the output of the NOR circuit NR ₁ is always "1" when the power is turned on. Therefore, the output of the NOR circuit NR ₁ is "1". (Fig. 9 (8)),
The output of the NOR circuit NR ₂ becomes “0” (FIG. 9 (9)).
Therefore, the control circuit 31 outputs "1" as the alarm drive signal, and the alarm drive circuit 32 does not operate (FIG. 9 (10)).

However, when the product 3 is removed from the clear case 2 of the anti-theft device 1 while being displayed on the display shelf 41, the micro switch 4 is turned on and the NAND circuit ND
The input of ₂ becomes "0", and thereafter the electronic buzzer 15 sounds.

<In case of theft>

Next, it is assumed that the product 3 is stolen in the clear case 2 of the anti-theft device 1. That is, it is assumed that the product 3 is put in a bag for the purpose of theft. In order to achieve such a state, it is usually accompanied by vibration and exposed to lighting until it is put in the bag.
Therefore, in the period T ₂ of FIG. 9, the vibration sensor 13
When the vibration is detected (period T _{21 in} FIG. 9 (2)), the illumination is detected by the optical sensor 5b (see FIG. 9).
(1)), Inverter circuit I in front of auxiliary control circuit 30
The input of V ₀ becomes “1”, and the inverter circuit IV in the subsequent stage
The output of ₁ also becomes "1", and the power is supplied to the frontmost circuit portion of the control circuit 31 (Fig. 9 (4)).

Further, the auxiliary control circuit 30 outputs electric power for about 15 seconds by the action of the capacitor C ₀ even if the vibration sensor 13 stops detecting vibration.
The voltage (“1”) of the capacitor C ₀ is input to the inverter circuit IV _{0 of the} preceding stage (FIG. 9 (3)).

During the power supply period of 15 seconds, the optical sensor 5a detects the optical pulse of the fluorescent lamp 42, and at the connection point between the optical sensor 5a and the resistor R ₂ , a period as shown in FIG. At 10 mS [millisecond], it appears as an optical pulse on a bias of about 0.6V. Therefore, the signal appearing at the connection point between the optical sensor 5a and the resistor R ₂ is applied to one input terminal of the operational amplifier OP via the capacitor C _1, and the forward voltage of the diode D ₂ is applied to the operational amplifier OP.
Input to the other input terminal of. The output signal of the operational amplifier OP is differentiated by the capacitor C ₂ and the result shown in FIG.
The signal becomes as shown in (B), and this is the transistor T.
Input to the base of _r1 . Then the transistor T
_r1 is turned on only when a differential waveform is input, and a sawtooth waveform is output to the collector of the transistor T _r1 as shown in FIG. 9C. When the sawtooth waveform is input to the inverter circuit IV ₂ , the sawtooth waveform is cut out at a constant level by the action of the threshold level of the inverter circuit IV ₂ . A narrow pulse signal as shown in FIG. 9D is output from the output terminal of the inverter circuit IV ₂ . This pulse signal is
It has a frequency of 100 Hz and is integrated by the resistor R ₆ and the capacitor C ₄ so that the voltage becomes “1” (FIGS. 9 (6) and 10 (D)). This voltage (“1”) is input to the inverter circuit IV ₃ and the NAND circuit ND ₁ . As a result, the NOR circuit NR ₁ ,
The flip-flop composed of NR ₂ is a NOR circuit NR
₁ outputs "1" (FIG. 9 (8)), the output of the NOR circuit NR ₂ will remain in the "0" (FIG. 9 (9)).

Then, when the article 3 and the anti-theft device 1 are put in a dark place such as a bag within 15 seconds, the optical sensor 5a stops detecting the optical pulse (see FIG. 9).
(5) At time t ₁ ), naturally, the signal as shown in FIG. 10A disappears, so that the differential signal is not applied to the base of the transistor T _r1 . Therefore, the transistor T _r1
Turns off and its collector becomes "1", so that the output of the inverter circuit IV ₂ changes to "0" (time t _{1 in} FIG. 9 (6)). Thus, the input of the inverter circuit IV ₃ is "0" and the output of the inverter circuit IV ₃ is "1", and the resistor R ₇ and the signal from the integrator capacitor C _5, the input portion of the inverter circuit IV ₃ A NAND logic is applied to the signal and the NAND circuit ND ₁ , and a pulse having a constant width is output from the output of the NAND circuit ND ₁ (time t _{1 to} t _{2 in} FIG. 9 (7)). As a result, in the flip-flop formed by the NOR circuits NR ₁ and NR ₂ , the output of the NOR circuit NR ₁ is “0” (FIG. 9 (8), time t).
_{After 1} ), the output of the NOR circuit NR ₂ becomes “1” (FIG. 9).
(9) after time t _1). As a result, the alarm drive circuit 32 is driven, “1” is supplied to the input of the inverter circuit IV _{0 in} the front stage, and the output of the inverter circuit IV _{1 in} the rear stage also becomes “1”, so that the power of the control circuit 31 is increased. Since the power is supplied to the frontmost circuit unit, the circuit continues to operate even if the vibration disappears (FIG. 9 (4)).

In such a state, the antitheft device 1 is taken out of the bag, and the optical sensor 5 is activated as shown in the period T _3.
When a detects the light pulse again, the inverter circuit IV ₃
Becomes ₁ and the flip-flop composed of the NOR circuits NR ₁ and NR ₂ is reset and the electronic buzzer 15 stops ringing.

Even if it is taken out of the room 40 in a state where it is exposed to light, if it comes out of the exit 43, unmodulated light from the sun will be emitted. For this reason, the optical sensor 5a has a frequency of 1 depending on the commercial frequency generated from the fluorescent lamp 42.
It is determined that the antitheft device 1 has moved to the outside from the area 49 because the optical pulse of 00 Hz is not input, and the electronic buzzer 15 sounds by the above-described operation. Further, when it is taken out of the room 40 in the lighted state at night, and when the outside of the area 49 is dark when exiting from the exit 43, vibration is detected by the vibration sensor 13 as described above. After that, it is detected that the optical sensor 5b has changed from a bright state to a dark state, and similarly, it is determined that there is theft, and the electronic buzzer 15 sounds.

As described above, in the present embodiment, vibration and light are detected to acoustically notify theft or the like.

As described above, the anti-theft device 1 has the vibration sensor 1 when the optical sensor 5b detects light.
When vibration is detected by 3, when the optical sensor 5a no longer detects a light pulse, it is determined that the theft has occurred, and the electronic buzzer 15 is sounded to issue an alarm.

In the anti-theft device 1, the optical sensor 5a may not detect an optical pulse when the vibration sensor 13 senses vibration at night. For example, the vibration sensor 13 may turn on due to an earthquake or a vibration caused by transportation, which easily causes a malfunction. However, in order to prevent such a malfunction, the fluorescent lamp 42
When is not lit, the optical sensor 5b does not turn on, and even if the vibration sensor 13 turns on, the anti-theft device 1 does not operate.

As described above, according to the present embodiment, it is possible to detect theft with certainty by using an ordinary fluorescent lamp and to eliminate the need for a device that emits a strong electromagnetic wave. Since a resonator for detecting the light and an illuminating device having another frequency are unnecessary, the outer shape can be downsized.

FIG. 11 is an explanatory view showing a usage example of another embodiment of the present invention. In FIG. 11, for example, a jewelry store 5
Consider the use of the anti-theft device 1 when a large number of stores such as 1, a record store 52, a watch store 53 coexist, and these stores are connected by a corridor 54. Such a plurality of stores corresponds to, for example, a shopping center, a joint store, a rental store of a building, and the like, and the jewelry store 5
A counter 55 for decorating jewelry is installed in the store 1, shelves 56, 57 and 58 for storing CDs, cassette tapes, etc. are arranged in the record store 52, and counters 59 and 60 for decorating the clock in the clock store 53. Are arranged. In this case, the jewelry store 51 drives and illuminates the illuminating lamp with the power of 200 Hz, the record store 52 drives and illuminates the illuminating lamp with the power of 100 Hz, and the clock store 53 drives the illuminating lamp with the power of 150 Hz. The corridor 54 is driven by an ordinary commercial power source of 50 Hz to illuminate.

At this time, the anti-theft device 1 outputs "1" by an optical pulse according to the illumination frequency of the store in which the anti-theft device 1 is used, instead of the low-pass filter consisting of the resistor R ₆ and the capacitor C ₄ in the control circuit 31. By using a bandpass filter, it becomes possible to use it in the store group.

For example, in the anti-theft device 1a used in the jewelry store 51, the pass frequency of the band pass filter provided in the control circuit 31 may be set to 400 Hz. In this way, for example, by taking the product 3 of the anti-theft device 1a from the jewelery store 51 to the corridor 54, the anti-theft device 1 can be operated in four steps.
Since the optical pulse of 00 Hz cannot be detected, the alarm is generated by the same operation as in the first embodiment.
Of course, for example, even if the product 3 with the anti-theft device 1a is taken out from the jewelry store 51 to the record store 52, the anti-theft device 1
Will not be able to detect the 400 Hz light pulse, and will generate an alarm.

The anti-theft devices 1b and 1c placed in the other stores 52 and 53 are replaced by the control circuit 31 in place of the low pass filter used in the first embodiment of the band pass filter capable of effectively detecting the illumination light frequency of each store. By providing the product 3 in the store, it is possible to prevent the product 3 from being stolen at each store.

According to the above-mentioned embodiment, although an additional inverter power supply is required for lighting, it is possible to reliably prevent theft at a place where many stores coexist, and there is no need for a device that radiates a strong electromagnetic wave. Because it is out of the scope of radio law,
Moreover, since the resonator for detecting the electromagnetic wave and the illumination device of other frequency are unnecessary, the outer shape of the anti-theft device can be downsized.

[0044]

As described above, according to the present invention, when a vibration sensor senses a vibration and the light sensor stops detecting light of a certain frequency, it is determined that a theft has occurred. Since an alarm is issued, theft can be reliably prevented with a simple device.

Further, according to the present invention, since the illumination is performed only by the light having a certain frequency, a device which radiates a strong electromagnetic wave and a resonator for detecting the electromagnetic wave are not required on the antitheft device side. Therefore, the number of parts is significantly reduced, and the antitheft device can be downsized.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a block diagram showing the whole of the embodiment.

FIG. 3 is a perspective view showing an example of a vibration sensor used in an embodiment of the present invention.

FIG. 4 is a block diagram showing an entire electric circuit of the embodiment.

FIG. 5 is a circuit diagram showing a specific configuration example of the circuit configuration of the embodiment.

FIG. 6 is a circuit diagram showing a specific configuration example of the circuit configuration of the same embodiment.

FIG. 7 is a perspective view showing an example of equipment using the same embodiment.

FIG. 8 is an explanatory diagram of an illumination area of the example.

FIG. 9 is a time chart for explaining the operation of the embodiment.

FIG. 10 is a waveform chart for explaining the operation of the embodiment.

FIG. 11 is an explanatory diagram for explaining another embodiment of the present invention.

[Explanation of symbols]

 1 Anti-theft device 2 Clear case 3 Product 4 Micro switch 5a Optical sensor 5b Optical sensor 13 Vibration sensor 15 Electronic buzzer (alarm) 30 Auxiliary control circuit 31 Control circuit 32 Alarm drive circuit

Claims (1)

Claim: What is claimed is: 1. An optical sensor for converting light and darkness of light into an electric signal, a vibration sensor for converting mechanical vibration into an electric signal, and an electric signal from the vibration sensor for taking in the vibration sensor. Auxiliary control circuit that supplies power for a certain time only when detecting vibration, and outputs an alarm drive signal when the electric signal from the optical sensor is outside the predetermined frequency band when power is supplied from the auxiliary control circuit The anti-theft device, comprising: a control circuit for operating the alarm device and an alarm drive circuit for generating an alarm by driving an alarm device by an alarm drive signal from the control circuit.