JP2007000121A - Apparatus for threatening small animal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small animal-threatening apparatus capable of surely detecting small animals in a caution area and threatening the small animals. <P>SOLUTION: The small animal-threatening apparatus is equipped with a small animal-detecting sensor D which is a small animal-detecting means for detecting whether a small animal A exists in a caution area or not, a threatening means 70 for threatening the small animal A in the caution area and a controller 80 which is a control means for controlling the threatening means 70 based on the output of the small animal-detecting sensor D. The small animal-detecting sensor D has a sound wave-feeding element 10 capable of feeding sound wave by applying thermal shock to air, a sound wave-receiving element 30 for receiving sound wave fed from a sound wave-feeding element 10 and reflected by an object, an operation part 44 for obtaining the distance to the object and a direction in which the object exists based on a time required from a time when the sound wave-feeding element 10 feeds sound wave to a time when the sound wave-receiving element 30 receives the sound wave and a determining part 45 for determining whether the small animal A exists or not in the caution area by comparing a size of the object existing in the caution area with a threshold based on three-dimensional data obtained in the operation part 44. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a small animal threatening device for threatening small animals (for example, dogs, cats, crows, etc.) that have entered a warning area.

  Conventionally, it has been a problem that small animals such as dogs, cats and crows break garbage bags and trash in garbage collection places such as condominiums, residential areas, and downtowns.

Conventionally, a small animal threatening device provided with a heat ray sensor as a small animal detection means for detecting a small animal in a warning area and a threatening means for threatening the small animal with ultrasonic waves or light when the small animal is detected by the heat ray sensor. (For example, Patent Documents 1 and 2), and it has been proposed to install this kind of small animal threatening device in a garbage collection site or the like.
JP 2002-34434 A JP 2001-333687 A

  However, in the small animal threatening devices disclosed in Patent Documents 1 and 2, since the heat ray sensor is used as the small animal detection means, it is difficult to distinguish between humans and small animals and it is not necessary to activate the threatening means. Intimidation may be activated, small animals that have entered the alert area may not be detected during the day due to the effects of sunlight or reflected light, and the threat may not be activated. Sometimes, small animals cannot be detected even though they exist in the alert area.

  The present invention has been made in view of the above reasons, and an object of the present invention is to provide a small animal threatening device that can detect and threaten small animals in a warning area more reliably.

  The invention of claim 1 is a small animal detection means for detecting the presence or absence of a small animal in a warning area, a threatening means for threatening a small animal in the warning area, and a threatening means when a small animal is detected by the small animal detection means. A small-animal detection means including a transmission element capable of transmitting a sound wave by applying a thermal shock to air and a drive circuit for driving the transmission element. A receiving device having a receiving element for receiving a sound wave transmitted from the transmitting element and reflected by an object, and converting the received sound wave into a received signal that is an electric signal; A calculation unit that calculates the distance to the object and the direction in which the object exists based on the time from when the sound wave is transmitted until the sound wave is received by the receiving element, and the distance and direction determined by the calculation unit Based on 3D information The size of the objects present in the area as compared with the threshold value; and a determining section for determining the presence or absence of small animals.

  According to the present invention, a sound wave having a short generation period and a short reverberation time can be transmitted from the wave transmitting element into the alert area, and the alert area is based on the three-dimensional information of the distance and the direction obtained by the calculation unit. The size of the object present inside is compared with a threshold value to determine whether or not a small animal exists, so it is possible to distinguish adults and small animals from the size of the object, and it is possible to detect small animals regardless of day or night. Moreover, since small animals can be detected even after the movement of small animals stops in the alert area, it is possible to detect and threaten small animals in the alert area more reliably, and human beings are detected as small animals and threatened means It can be prevented from being controlled.

  The invention of claim 2 is characterized in that, in the invention of claim 1, the threatening means threatens a small animal with ultrasonic waves.

  According to this invention, a small animal can be threatened without giving discomfort to a person in the vicinity of the alert area.

  According to a third aspect of the present invention, in the invention of the second aspect, the wave transmitting element includes a base substrate, a heating element layer formed on one surface side of the base substrate, and a base substrate on the one surface side of the base substrate. A thermal insulation layer interposed between the heating element layer and generating a sound wave by applying a thermal shock to the air due to a temperature change of the heating element layer when the heating element layer is energized. It is also characterized by serving.

  According to the present invention, it is not necessary to prepare a dedicated device as the threatening means, so that the cost can be reduced and the size of the entire apparatus can be reduced.

  In the invention of claim 1, there is an effect that it is possible to more reliably detect and threaten the small animals in the alert area.

  Hereinafter, the small animal threatening device of this embodiment will be described with reference to FIG.

  As shown in FIGS. 1B and 1C, the small animal threatening device B of the present embodiment is installed on a wall surface 100a of a garbage collection place 100 that collects garbage bags 90 containing household garbage in an apartment, for example. .

  As shown in FIG. 1A, the small animal threatening device B includes a small animal detection sensor D, which is a small animal detection means for detecting the presence or absence of a small animal A (see FIG. 1B) in the warning area, A threatening means 70 threatening the small animal A and a control device 80 which is a control means for controlling the threatening means 70 so that the threatening means 70 threatens the small animal A when the small animal A is detected by the small animal detection sensor D are provided. ing. The control device 80 is mainly composed of a microcomputer.

  As the small animal A, for example, a dog, a cat, a crow and the like are assumed, and the threatening means 70 includes an ultrasonic wave generation means for generating an ultrasonic wave of a predetermined frequency (for example, 25 kHz) for threatening the small animal A, Light emitting means for emitting light for threatening the small animal A, and the ultrasonic wave generating means is composed of an ultrasonic vibrator composed of a piezoelectric element and a drive circuit for driving the ultrasonic vibrator. The means includes a light emitting element and a lighting circuit for lighting the light emitting element.

  The small animal detection sensor D includes a transmission element 10 having a transmission element 10 capable of transmitting a sound wave by applying a thermal shock to the air and a drive circuit 20 for driving the transmission element 10, and transmitting from the transmission element 10. And receiving the sound wave reflected by the object Ob and receiving the sound wave received by the wave receiving device 3 that converts the received sound wave into a received wave signal, which is an electrical signal, and processing the output of the wave receiving device 3 The signal processing circuit 4 includes the object Ob (FIG. 2 (FIG. 2 ( a) (see a)) and a calculation unit 44 for determining the azimuth in which the object Ob exists, and three-dimensional information of the distance and azimuth obtained by the calculation unit 44 (that is, up to the object Ob in each direction in the alert area). In the alert area based on distance information) And a determination unit 45 for determining the presence or absence of A.

  Here, the determination unit 45 compares the size of the object Ob with a threshold value, and determines that the object Ob is a person and the small animal A does not exist in the alert area when the size of the object Ob is equal to or greater than the threshold value. When the size of the object Ob is less than the threshold value, it is determined that the object Ob is the small animal A and the small animal A exists in the alert area only when the object Ob below the threshold value is continuously detected the specified number of times. To do. That is, if the object Ob is a child who has thrown away the garbage bag 90 in the garbage collection place 100, it is considered that the staying time in the warning area of the garbage collection place 100 is relatively short, whereas the garbage collection place 100 If it is small animal A who has come to search for food, it is considered that the staying time in the warning area of the garbage collection place 100 is relatively long. The possibility of determining as existence can be reduced.

  The determination unit 45 determines whether or not the small animal A exists based on the size of the object Ob. If the small animal A has come to search for food at the garbage collection site 100 as described above, the garbage collection is performed. Since it is considered that the staying time in the warning area of the place 100 is relatively long, a storage unit for storing time series data of information on the position where the object Ob exists is provided, and the movement status of the object Ob (the object Ob (Movement) may be tracked to determine whether or not the object Ob is the small animal A. Moreover, the calculating part 44 and the judgment part 45 are realizable by mounting an appropriate program in a microcomputer.

  On the other hand, when the determination unit 45 determines that the small animal A exists in the alert area, the control device 80 causes the threatening means 70 to output ultrasonic waves and light for threatening the small animal A from the threatening means 70. Control. Note that the determination unit 45 outputs a detection signal only when it is determined that the small animal A exists in the alert area, and the control device 80 controls the threatening means 70 in response to the detection signal from the determination unit 45.

  Hereinafter, the small animal detection sensor D will be described with reference to FIGS.

  The wave transmitting device 1 includes the wave transmitting element 10 and the drive circuit 20 described above. The drive circuit 20 includes a timing control unit that controls the timing at which the sound wave is intermittently transmitted from the transmission element 10. The wave transmitting element 10 is mounted on a first circuit board 23 made of a rectangular plate-like glass epoxy board.

  On the other hand, the wave receiving device 3 includes a plurality of the wave receiving elements 30 described above. Here, the small animal detection sensor D includes ten wave receiving elements 30 as one rectangular plate-like glass epoxy so that not only the distance to the object Ob but also the direction in which the object Ob exists can be measured as described above. The second circuit boards 24 made of a substrate are arranged on a plane. Specifically, five receiving elements 30 are arranged at a predetermined pitch in a direction along one side of the second circuit board 24, and five receiving elements 30 are arranged in a direction orthogonal to the one side. They are arranged at a predetermined pitch.

  In order to simplify the explanation, it is assumed that the wave receiving elements 30 are arranged at a predetermined pitch only in the direction along the one side on the same plane, and the angle of the wavefront of the sound wave with respect to the surface on which the wave receiving elements 30 are arranged. 11 is assumed, the arrival direction of the sound wave (that is, the azimuth angle where the object Ob is present with respect to the wave receiving device 3) is θ, the sound speed is c, and the wavefront of the sound wave, as shown in FIG. The distance (delay distance) between the wavefront of the sound wave and the center of the other wave receiving element 30 at the time when the wave reaches one wave receiving element 30 among the adjacent wave receiving elements 30 is d, and the adjacent wave receiving elements If the distance between the centers of 30 (the predetermined pitch) is L, the time difference Δt at which the wavefront of the sound wave reaches between adjacent wave receiving elements 30 is Δt = d / c = L · sin θ / c. Therefore, if the time difference Δt is known, the direction in which the object Ob exists can be calculated. Here, the predetermined pitch is preferably set to about 0.5 times the wavelength of the sound wave transmitted from the transmission element 10.

  The signal processing circuit 4 includes a signal amplifying unit 41 having a plurality of amplifiers 41a for amplifying the received signals output from the receiving elements 30, and digitally receiving the analog received signals amplified by the amplifiers 41a. A / D converter 42 that converts the received signal into a received signal, a memory 43 that stores the output of the A / D converter 42, and a control signal that controls the transmission timing of sound waves from the timing controller. An operation for obtaining the distance to the object Ob by using the data of the received signal stored in the memory 43 by operating the A / D converter 42 for a predetermined receiving period when receiving the timing signal output in synchronization. Based on the three-dimensional information of the above-described calculation unit 44 for calculating the direction in which the object Ob exists and the distance and direction calculated by the calculation unit 44, the presence or absence of the small animal A in the alert area is determined. And a determination portion 45 of the predicate. The signal processing circuit 4 is provided on a third circuit board 25 made of a glass epoxy board having a rectangular plate shape.

  Here, the calculation unit 44 receives the timing signal (that is, the timing when the sound wave is transmitted from the transmission element 10) and the time when the digital reception signal is stored in the memory 43 (the signal processing circuit 4). If the delay time is ignored, the time difference (in other words, the timing at which the sound wave is received by the wave receiving element 30) (in other words, from the time when the wave transmitting device 1 transmits the sound wave to the time when the wave receiving device 3 receives the wave) ) Based on the distance calculation means for calculating the distance to the object Ob and the received signal data of each receiving element 30 stored in the memory 43 (the object Ob). Azimuth detecting means for obtaining the direction of arrival of the sound wave reflected by (3). Here, the azimuth detecting means obtains the arrival direction of the sound wave with respect to the wave receiving device 3 based on the time difference of the time when the sound wave is received by each wave receiving element 30 and the arrangement position of each wave receiving element 30.

Note that the small animal detection sensor D in the present embodiment may propagate a maximum distance of 6 m in the air if the maximum measurement distance is 3 m, for example, but the sound wave transmitted from the transmission element 10 is Attenuation is caused by propagation loss such as diffusion loss (distance attenuation), absorption loss, reflection loss, and the like, so that the amplification gain (voltage gain) of each amplifier 41a is appropriately set to prevent the S / N ratio from being lowered. If the maximum measurement distance is 3 m as described above, the time required for a sound wave to propagate a distance of 6 m in the air is about 18 ms. Therefore, the above reception period may be set to about 18 ms. . The memory 43 stores the received signal of each receiving element 30 during the receiving period. In other words, the memory 43 stores [number of receiving elements 30] × [from each receiving element 30. Therefore, for example, the number of receiving elements 30 is 10, the receiving period is 18 ms, and the sampling period of the A / D converter 42 is 1 μs. When (sampling frequency is 1 MHz), one data is 16 bits, and (10 [pieces]) × {(18 × 10 ⁻³ ) ÷ (1 × 10 ⁻⁶ ) × 16} = 2880000 bits = 360 kbytes capacity Therefore, an SRAM having a capacity of 360 kbytes or more may be used.

  The azimuth detecting means described above receives a received signal obtained by delaying the received signal of each receiving element 30 stored in the memory 43 by a delay time corresponding to the arrangement pattern (arrangement position) of each receiving element 30. A delay unit that outputs a set, an adder that adds a set of received signals delayed by the delay unit, a peak value that exceeds the threshold by comparing the magnitude relationship between the peak value of the output waveform of the adder and an appropriate threshold Judgment means for judging that the direction corresponding to the combination of delay times set by the delay means when the value is obtained is the direction in which the object Ob exists (the arrival direction of the sound wave). Note that the distance calculation means and the direction detection means of the calculation unit 44 can be realized by installing appropriate programs in the microcomputer constituting the calculation unit 44 and the determination unit 45.

  By the way, the small animal detection sensor D uses a thermal excitation type sound wave generating element that generates a sound wave by applying a thermal shock to the air as the wave transmitting element 10, so that the Q value of the resonance characteristic of the wave transmitting element 10 is piezoelectric. A reverberation component included in a received signal that is sufficiently small compared to the element to transmit a sound wave having a short reverberation time, and that the Q value of the resonance characteristics of the receiving element 30 is sufficiently smaller than that of the piezoelectric element. A capacitance type microphone with a short generation period is used.

  Here, as shown in FIG. 4, the wave transmitting element 10 includes a heat insulating layer (including a porous silicon layer) on one surface (upper surface in FIG. 4) side of a base substrate 11 made of a single crystal p-type silicon substrate. A heat insulating layer 12 is formed, a heat generating layer 13 made of a metal thin film is formed on the heat insulating layer 12, and a pair of pads 14 electrically connected to the heat generating layer 13 on the one surface side of the base substrate 11. , 14 are formed by thermally excited sound wave generating elements. The planar shape of the base substrate 11 is a rectangular shape, and the planar shapes of the heat insulating layer 12 and the heating element layer 13 are also formed in a rectangular shape. The heating element layer 13 may be formed on at least the one surface side of the base substrate 11.

  In the above-described transmission element 10, when current is applied between the pads 14, 14 at both ends of the heating element layer 13 to cause a rapid temperature change in the heating element layer 13, the air in contact with the heating element layer 13 is rapidly increased. Temperature change (thermal shock) occurs (that is, thermal shock is applied to the air in contact with the heating element layer 13). Accordingly, the air in contact with the heating element layer 13 expands when the temperature of the heating element layer 13 rises and contracts when the temperature of the heating element layer 13 decreases. Therefore, by appropriately controlling energization to the heating element layer 13 Sound waves that propagate in the air can be generated. In short, the thermal excitation type sound wave generating element constituting the wave transmitting element 10 propagates the medium by converting the rapid temperature change of the heating element layer 13 accompanying energization to the heating element layer 13 into expansion and contraction of the medium. Generates sound waves. In the present embodiment, the heating element layer 13 constitutes a thin plate-like heating element. Here, the thermal excitation type sound wave generating element only needs to include at least a thin plate-like heating element. For example, a rapid temperature change of the heating element accompanying energization of the heating element using a thin aluminum plate as a heating element. A sound wave may be generated by a thermal shock due to.

Moreover, since the above-described transmission element 10 uses a p-type silicon substrate as the base substrate 11, and the thermal insulating layer 12 is composed of a porous silicon layer having a porosity of about 60 to about 70%, A porous silicon layer serving as the thermal insulating layer 12 can be formed by anodizing a part of a silicon substrate used as the base substrate 11 in an electrolytic solution made of a mixed solution of hydrogen fluoride aqueous solution and ethanol. Since the porous silicon layer has a lower thermal conductivity and heat capacity as the porosity becomes higher, the thermal conductivity and heat capacity of the heat insulating layer 12 are made smaller than the heat conductivity and heat capacity of the base substrate 11, and heat insulation is performed. By making the product of the thermal conductivity and the thermal capacity of the layer 12 sufficiently smaller than the product of the thermal conductivity and the thermal capacity of the base substrate 11, the temperature change of the heating element layer 13 can be efficiently transmitted to the air. The heat generating body layer 13 and the air can efficiently exchange heat, and the base substrate 11 can efficiently receive the heat from the heat insulating layer 12 and release the heat of the heat insulating layer 12 to generate heat. It is possible to prevent heat from the body layer 13 from being accumulated in the heat insulating layer 12. Note that the porosity formed by anodizing a single crystal silicon substrate having a thermal conductivity of 148 W / (m · K) and a heat capacity of 1.63 × 10 ⁶ J / (m ³ · K) is 60%. The porous silicon layer is known to have a thermal conductivity of 1 W / (m · K) and a heat capacity of 0.7 × 10 ⁶ J / (m ³ · K). In the present embodiment, as described above, the thermal insulation layer 12 is composed of a porous silicon layer having a porosity of approximately 70%, and the thermal conductivity of the thermal insulation layer 12 is 0.12 W / (m · K), The heat capacity is 0.5 × 10 ⁶ J / (m ³ · K).

  The heating element layer 13 is formed of tungsten, which is a kind of refractory metal, but the material of the heating element layer 13 is not limited to tungsten, and for example, tantalum, molybdenum, iridium, aluminum, or the like may be employed. Further, in the above-described transmission element 10, the thickness of the base substrate 11 is 300 to 700 μm, the thickness of the thermal insulating layer 12 is 1 to 10 μm, the thickness of the heating element layer 13 is 20 to 100 nm, and the thickness of each pad 14. Although the thickness is 0.5 μm, these thicknesses are merely examples and are not particularly limited. Further, Si is adopted as the material of the base substrate 11, but the material of the base substrate 11 is not limited to Si, and, for example, it can be made porous by anodizing treatment such as Ge, SiC, GaP, GaAs, InP or the like. Other semiconductor materials may be used.

  As described above, the wave transmitting element 10 generates a sound wave in accordance with the temperature change of the heating element layer 13 caused by energization of the heating element layer 13 via the pair of pads 14 and 14. When the drive input waveform consisting of the drive voltage waveform or the drive current waveform applied to is a sine wave waveform having a frequency f1, for example, the frequency of the temperature oscillation generated in the heating element layer 13 is ideally the frequency f1 of the drive input waveform. The frequency f2 is doubled, and a sound wave having a frequency approximately twice that of the drive input waveform f1 can be generated. That is, the above-described transmission element 10 has a flat frequency characteristic and can change the frequency of the generated sound wave over a wide range. Further, in the above-described transmission element 10, for example, a half-cycle isolated wave having a sine wave waveform is applied as a drive input waveform from the drive circuit 20 to the pair of pads 14 and 14, as shown in FIG. It is possible to generate a sound wave P1 having substantially one cycle with little reverberation. In the present embodiment, when generating a sound wave P1 of approximately one cycle as shown in FIG. 5A, the time of one cycle of the sound wave P1 is set to the time of one cycle of ultrasonic waves of about 50 kHz to 70 kHz. Although there is this value, it is not particularly limited.

  In the above-described transmission element 10, when the drive voltage waveform applied to the heating element layer 13 via the pair of pads 14 and 14 is a Gaussian voltage waveform as shown in FIG. It is possible to transmit a Gaussian wave-shaped sound wave as shown in FIG.

  Here, a Gaussian wave-shaped sound wave as shown in FIG. 6B from the wave transmitting element 10 (here, the generation period of the sound wave is set to one cycle time of an ultrasonic wave of about 50 kHz to 70 kHz). For example, a circuit shown in FIG. 7 may be employed as the drive circuit 20. In the drive circuit 20 having the configuration shown in FIG. 7, a capacitor C is connected between both ends of the DC power supply E via a switch SW2, and a thyristor Th, an inductor L, a resistor R1, and a protective resistor R2 are connected between both ends of the capacitor C. A series circuit is connected, and the transmission element 10 is connected between both ends of the protective resistor R2. Further, the drive circuit 20 includes the above-described timing control unit that controls the timing at which the sound wave is transmitted from the transmission element 10 as described above, and the ON / OFF of the switch SW2 is controlled by the timing control unit and the thyristor. The timing for giving a control signal to Th is controlled. Here, in the drive circuit 20, the capacitor C is charged while the switch SW2 is on, but the timing control unit detects the voltage across the capacitor C, and if the voltage across the capacitor C exceeds a predetermined voltage value. A control signal is supplied to the gate of the thyristor Th after the switch SW2 is turned off. That is, in the drive circuit 20 having the configuration shown in FIG. 7, when a charge is accumulated in the capacitor C from the DC power source E and the voltage across the capacitor C exceeds the predetermined voltage value, a control signal is given from the timing control unit to the thyristor Th. Then, the thyristor Th is turned on, a voltage is applied between the pads 14 and 14 of the wave transmitting element 10, and a sound wave is transmitted along with the temperature change of the heating element layer 13. Here, by appropriately setting the inductance of the inductor L and the resistance value of the resistor R1, a drive voltage waveform having a Gaussian shape as shown in FIG. 6A is applied between the pads 14 and 14 of the transmission element 10. be able to.

  Further, the capacitance type microphone constituting the above-described wave receiving element 30 is formed using a micromachining technique. For example, as shown in FIG. 8, a window hole penetrating in the thickness direction in the silicon substrate. A frame 31 having a rectangular frame shape formed by providing 31a, and a cantilever-type pressure receiving portion 32 arranged across two opposite sides of the frame 31 on one surface side of the frame 31 are provided. Here, a thermal oxide film 35, a silicon oxide film 36 covering the thermal oxide film 35, and a silicon nitride film 37 covering the silicon oxide film 36 are formed on one surface side of the frame 31, and one end of the pressure receiving portion 32. Is supported by the frame 31 via the silicon nitride film 37, and the other end faces the silicon nitride film 37 in the thickness direction of the silicon substrate. Further, a fixed electrode 33 a made of a metal thin film (for example, a chromium film) is formed on a surface of the silicon nitride film 37 facing the other end of the pressure receiving portion 32, and the silicon nitride film 37 at the other end of the pressure receiving portion 32 is formed. A movable electrode 33b made of a metal thin film (for example, a chromium film) is formed on the opposite side of the opposite surface. A silicon nitride film 38 is formed on the other surface of the frame 31. The pressure receiving portion 32 is constituted by a silicon nitride film formed in a separate process from the silicon nitride films 37 and 38 described above.

  In the wave receiving element 30 including the capacitance type microphone having the configuration shown in FIG. 8, a capacitor having the fixed electrode 33a and the movable electrode 33b as electrodes is formed, so that the pressure receiving portion 32 receives the pressure of the sound wave. As a result, the distance between the fixed electrode 33a and the movable electrode 33b changes, and the capacitance between the fixed electrode 33a and the movable electrode 33b changes. Therefore, if a DC bias voltage is applied between pads (not shown) provided on the fixed electrode 33a and the movable electrode 33b, a minute voltage change occurs between the pads according to the sound pressure of the sound wave. The sound pressure of the sound wave can be changed to an electric signal.

  The structure of the capacitive microphone used as the wave receiving element 30 is not particularly limited to the structure shown in FIG. 8. For example, as shown in FIG. 9, the center portion is a peripheral portion on one surface side of the silicon substrate 141. A silicon layer having a first diaphragm portion 145 that is thinner than the first diaphragm portion 145 is provided, and a recess 142 is provided on the other surface of the silicon substrate 141, whereby the first diaphragm portion 145 and the gap 144 are formed at the center of the silicon substrate 141. In the structure in which the second diaphragm portion 143 that is opposed to each other is formed, the movable electrode 146 is provided on the first diaphragm portion 145 and the fixed electrode (not shown) is provided on the second diaphragm portion 143. It is good. The capacitive microphone used as the wave receiving element 30 is formed by processing a silicon substrate or the like by a micromachining technique or the like, and includes a movable electrode that receives a sound wave and a back plate that faces the diaphragm. A spacer that defines the gap length between the diaphragm portion and the back plate when not receiving sound waves is interposed between the fixed electrode and the plurality of exhaust holes in the back plate. It may have a structure.

  4 has a resonance characteristic Q value of about 1, and the wave receiving element 30 including the capacitive microphone shown in FIG. The Q value of the resonance characteristic is about 3 to 4, and the Q value is sufficiently smaller than that of the piezoelectric element. Compared to the case where piezoelectric elements are used for the transmitting element and the receiving element as in the conventional ultrasonic sensor. Thus, the angular resolution can be improved, and the angular resolution can be about 5 °. The distance resolution can be about 0.01 m. When a piezoelectric receiving element is used as the receiving element 30, a signal P4 due to the reverberation of the receiving element 30 is generated in the received signal of the receiving element 30 as shown in FIG. There is a possibility that the generation period of the received signal P3 due to the reflected wave (indirect wave) by the object Ob is a sound wave P1 (FIG. 5B) transmitted from the transmission element 10 as shown in FIG. 5 (a)), it is desirable to employ the above-described capacitance type microphone as the wave receiving element 30. FIG. 10A shows an example of a waveform of a sound wave transmitted by the transmission element 10 having the structure shown in FIG. 4, and FIG. 10B shows an output from the microphone having the structure shown in FIG. An example of the waveform of an output voltage (received signal) is shown.

  As described above, the small animal detection sensor D in the present embodiment is composed of a sound wave generating element that generates a sound wave when the wave transmitting element 10 applies a thermal shock to the air. The Q value of the piezoelectric element is smaller than the Q value of the resonance characteristic of the piezoelectric element, and the reverberation time of the transmitted sound wave can be shortened compared to the case where the piezoelectric element is used as the transmitting element as in the conventional ultrasonic sensor. . In other words, the reverberation component contained in the sound wave transmitted from the transmission element 10 is less than that of the conventional ultrasonic sensor, and the generation period of the reverberation component can be shortened compared to the conventional ultrasonic sensor. In short, the small animal detection sensor D is composed of a device that generates a sound wave by applying a thermal shock to the air by the transmitting element 10, and therefore, a dead zone caused by a reverberation component in the sound wave transmitted from the transmitting element 10 is conventionally detected. It can be shortened compared to an ultrasonic sensor using a piezoelectric element.

  Further, in the small animal threatening device B of the present embodiment, a sound wave generating element having the structure of FIG. 4 is used as the wave transmitting element 10 of the small animal detection sensor D, and the Q value of the resonance characteristic is about 1, so the angular resolution is about 5 °. Since the determination unit 45 of the small animal detection sensor D determines whether or not the small animal A exists based on the three-dimensional information of the distance and the direction obtained by the calculation unit 44 as described above, is the object Ob the small animal A? Can be determined based on the size of the object Ob, and the control device 80 controls the threatening means 70 when receiving the detection signal from the determination unit 45, thereby preventing unnecessary operation of the threatening means 70. As a result, it is possible to save power and prevent discomfort for people in the vicinity of the alert area.

  Further, since the wave receiving element 30 is composed of a capacitance type microphone that converts the sound pressure of a sound wave into a change in capacitance, the Q value of the resonance characteristic of the wave receiving element is the Q of the resonance characteristic of the piezoelectric element. The reverberation time in the received signal can be shortened as compared with the conventional case where a piezoelectric element is used as the receiving element. In other words, the generation period of the reverberation component included in the received signal of the receiving element 30 can be shortened compared to the conventional case. Therefore, compared to the case where a piezoelectric element is used as the wave receiving element 30, the reverberation component in the wave receiving signal output from the wave receiving element 30 can be reduced, and the reverberation in the wave receiving signal output from the wave receiving element 30 can be reduced. Dead zones due to the components can be shortened.

  By the way, the small animal detection sensor D includes a first circuit board 23 on which the wave transmitting element 10 is mounted, a second circuit board 24 on which each wave receiving element 30 is mounted, and a third circuit board provided with the signal processing circuit 4. A housing 50 (see FIG. 2A) in which the circuit board 25 and the like are accommodated is provided.

  As shown in FIG. 2A, the housing 50 includes a housing body 51 made of a synthetic resin formed in a rectangular box shape with one surface (upper surface in FIG. 2A) opened, and the one surface of the housing body 51. A rectangular plate-shaped housing lid 52 fixed to the side. Here, the housing lid 52 has a first window hole 52a that exposes the transmission surface of the transmission element 10 as an opening that exposes the transmission surface of the transmission element 10 and the reception surface of each reception element 30, and each Since the second window hole 52b that exposes the wave receiving surface of the wave receiving element 30 is formed separately, compared with the case where both the window holes 52a and 52b are formed continuously, the wave transmitting element 10 It is possible to suppress the sound wave from directly propagating to each wave receiving element 30 and generating the wave receiving signal P2 caused by the direct wave as shown in FIGS. 5B and 5C. The noise of the received signal output from each can be reduced, and the timing of transmitting the sound wave and the period T3 and T4 until the reception period starts (see FIGS. 5B and 5C) Can be shortened. Each of the window holes 52a and 52b penetrates in the thickness direction of the housing lid 52, and the opening shape is rectangular.

  Further, in the small animal detection sensor D in the present embodiment, the above-described wave transmitting element 10 and each wave receiving element 30 are disposed in the housing 50 so as to recede from the portion where the respective window holes 52a and 52b are formed, and The first circuit board 23 and the second circuit board 24 are spaced apart from each other in a plane parallel to the housing lid 52, and surround the transmission element 10 on the surface of the first circuit board 23 that faces the housing lid 52. Since the first sound-absorbing member 6a having a rectangular frame shape and the second sound-absorbing member 6b having a rectangular frame shape surrounding each wave receiving element 30 on the surface of the second circuit board 24 facing the housing lid 52 are provided. Further, it is possible to more reliably prevent the sound wave from directly propagating from the transmitting element 10 to each receiving element 30.

  The third circuit board 25 is fixed to the inner bottom surface of the housing main body 51 with an adhesive, and the first circuit board 23, the second circuit board 24, and the third circuit board 25 are between them. Since the sound absorbing member 7 is interposed, the vibration of the wave transmitting element 10 is transmitted to the second circuit board 24 via the third circuit board 25 and transmitted to the received signal to be processed by the signal processing circuit 4. Generation of noise due to vibration of the wave element 10 can be prevented. The received signal output from each receiving element 30 is transmitted to the signal processing circuit 4 via the connector 60 that electrically connects the second circuit board 24 and the third circuit board 25. .

  Further, as shown in FIGS. 2A and 12B, the small animal detection sensor D has a sound-permeable waterproof sheet (for example, a porous sheet) formed in each window hole 52a, 52b of the housing lid 52. The waterproof sheet 8 is covered with a frame-like bezel 9 (see FIGS. 2A and 13) formed of the same material as the housing lid 52. Here, since the bezel 9 is fixed to the outer surface of the housing lid 52 in such a manner that the periphery of the waterproof sheet 8 is sandwiched between the bezel 9 and the housing lid 52, foreign matter such as dust, dust, insects, etc., is housed in the housing. 50 can be prevented from entering the housing 50 and causing a short circuit, or rain or water droplets entering the housing 50 and preventing the transmitting element 10 and each receiving element 30 from being deteriorated or destroyed. Can increase the sex. In the present embodiment, the outer peripheral shape of the waterproof sheet 8 is rectangular, and the bezel 9 is rectangular frame. Further, the sound absorbing member 6 shown in FIG. 12 (a) is obtained by integrating the above-described sound absorbing members 6a and 6b into one member. Compared to the case where the sound absorbing members 6a and 6b are used, the number of components can be reduced, and the distances between the first circuit board 23 and the second circuit board 4 and the housing lid 52 can be accurately aligned. .

  In the small animal detection sensor D, the first circuit board 23 is attached to the housing lid 52 via a plurality of (for example, four) spacers 17a (see FIG. 2B) with a fixing screw (not shown). The second circuit board 24 is attached to the housing lid 52 via a plurality of (for example, four) shock absorbing members 17b (see FIG. 2B). Here, each shock-absorbing member 17b interposed between the second circuit board 24 and the housing lid 52 is fixed to the second circuit board 24 and the housing lid 52 with an adhesive. Here, since the second circuit board 24 on which each receiving element 30 is mounted is attached to the housing 50 via the shock absorbing member 17b, the vibration of the housing 50 is transmitted to the second circuit board 24. The noise generated in the received signal of each receiving element 30 due to the vibration of the housing 50 can be reduced. That is, it is possible to prevent the noise P5 (see FIG. 5C) due to the vibration of the housing 50 from being generated in the received signal of the receiving element 30.

As a material of the housing body 51 and the housing lid 52, polyacetal, for example, Delrin (trade name), Duracon (trade name), or the like is adopted. In the present embodiment, the housing main body 51 and the housing lid 52 are made of synthetic resin such as polyacetal. However, these materials are not limited to synthetic resin, and have a lower density and insulating properties than metal. Any material may be used, and for example, it may be formed of ceramic. Here, since the housing 50 constituted by the housing main body 51 and the housing lid 52 is formed of synthetic resin or ceramic, the density of the material forming the housing 50 is higher than when the housing 50 is formed of metal. Therefore, it is difficult for sound waves to propagate through the housing 50, and the housing 50 is less likely to resonate with sound waves transmitted from the wave transmitting element 10. It is possible to prevent the noise P5 due to the occurrence of noise. Further, as the shock absorbing material 17b and the vibration-proof member, a gel material mainly made of silicone, for example, alpha gel: α _GEL (registered trademark) may be used.

  In the small animal threatening device B of the present embodiment described above, a sound wave having a short generation period and a short reverberation time can be transmitted from the transmission element 10 into the alert area, and the distance and direction obtained by the calculation unit 44 are calculated. Based on the three-dimensional information, the size of the object Ob existing in the alert area is compared with a threshold value to determine whether or not the small animal A exists, so that the adult and the small animal A can be distinguished from the size of the object Ob. In addition, the small animal A can be detected regardless of the day and night and the weather, and since the small animal A can be detected even after the movement of the small animal A stops in the warning area, the small animal A in the warning area can be detected more reliably. It can be detected and threatened, and it can be prevented that the person M is detected as the small animal A and the threatening means 70 is controlled.

  By the way, the threatening means 70 described above threatens the small animal A with ultrasonic waves and light. However, the threatening means 70 may threaten the small animal A only with ultrasonic waves, or threaten the small animal A with only ultrasonic waves. By doing so, the small animal A can be threatened without causing discomfort to people in the vicinity of the alert area, and even if the child in the alert area is detected as the small animal A, the child is discomforted. Never give.

  Further, if the threatening means for threatening the small animal A in the alert area threatens the small animal A only by the ultrasonic wave, the frequency f1 of the drive input waveform is twice as high as the transmission element 10 shown in FIG. Since the sound wave generating element capable of generating the sound wave of the frequency f2 can be used as a threatening means, it is not necessary to prepare a dedicated one as a threatening means, the cost can be reduced, and the small animal threatening apparatus B can be reduced in size as a whole. Can be realized.

The small animal threat device in embodiment is shown, (a) is a block diagram, (b), (c) is explanatory drawing of a usage pattern. The small animal detection sensor same as the above is shown, (a) is a schematic sectional view, and (b) is a schematic plan view of a main part in a state where a housing lid is removed. It is a principal part perspective view of the small animal detection sensor in the same as the above. It is a schematic sectional drawing of the wave transmitting element same as the above. It is operation | movement explanatory drawing same as the above. It is operation | movement explanatory drawing of the wave transmission element in the same as the above. It is a circuit diagram which shows an example of the drive circuit of the wave transmission element same as the above. The wave receiving element in the same as above is shown, (a) is a schematic perspective view partly broken, and (b) is a schematic sectional view. It is a schematic sectional drawing which shows the other structural example of the receiving element in the same as the above. It is operation | movement explanatory drawing of the small animal detection sensor same as the above. It is operation | movement explanatory drawing of the small animal detection sensor same as the above. The state which attached the sound-absorbing member and the waterproof sheet to the housing cover of the small animal detection sensor in the above is shown, (a) is a bottom view, and (b) is a plan view. It is a top view of the bezel in the same as the above.

Explanation of symbols

A small animal B small animal threatening device D small animal detection sensor 1 wave transmitting device 3 wave receiving device 4 signal processing circuit 10 wave transmitting element 20 drive circuit 30 wave receiving element 43 memory 44 arithmetic unit 45 judgment unit 70 threatening means 80 control device 90 garbage bag 100 Garbage collection site 100a Wall surface

Claims (3)

  Small animal detection means for detecting the presence or absence of small animals in the warning area, threatening means for threatening small animals in the warning area, and threatening means for threatening means to threaten small animals when the small animals are detected by the small animal detection means Control means for controlling, and the small animal detection means includes a transmission device capable of transmitting a sound wave by applying a thermal shock to the air, a transmission device having a drive circuit for driving the transmission device, and a transmission device. A wave receiving device having a wave receiving element for receiving a sound wave transmitted and reflected by an object and converting the received sound wave into a wave receiving signal that is an electric signal; and after the wave transmitting element transmits the sound wave Based on a calculation unit for obtaining the distance to the object and the direction in which the object exists based on the time until the sound wave is received by the wave receiving element, and on the basis of the three-dimensional information of the distance and direction obtained by the calculation unit In the alert area Small animal threatening apparatus characterized by having a determining section for determining the presence or absence of small animals to compare the size of the object with the threshold value.   The small animal threatening device according to claim 1, wherein the threatening means threatens the small animal with ultrasonic waves.   The wave transmitting element includes a base substrate, a heating element layer formed on one surface side of the base substrate, and a thermal insulating layer interposed between the base substrate and the heating element layer on the one surface side of the base substrate. The sound wave is generated by applying a thermal shock to the air due to the temperature change of the heating element layer accompanying energization of the heating element layer, and also serves as the threatening means. Small animal threatening device.

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