JP6944624B2 - Proximity sensor circuit - Google Patents

Description

The present invention relates to a circuit structure of a proximity sensor, and more particularly to a technique for improving a malfunction in a capacitance type proximity sensor.

The capacitance type proximity sensor detects a change in capacitance that occurs between a human body or the like as a detector and the sensor as proximity, and includes metal, resin, water, and the like as detectable objects. Compared to the infrared method, ultrasonic method, optical sensor method, etc., it has the feature that no special parts are required.

However, the change in capacitance is small, and if the cable to the detection unit is long, it is easily affected by noise, so it is difficult to install a remote sensor with a long lead wire.
Further, since the noise varies depending on the location, the reaction at the time of detection may be strong, weak, or not detected. Therefore, the detection tends to be unstable.
In addition, in places where the temperature and humidity change drastically, it may be affected at the time of detection.
Various methods have been proposed to deal with such a situation. For example, a technique for improving reliability by having a plurality of detection units and comparing differences has also been proposed.

The technique described in Patent Document 1 has a first detection electrode and a second detection electrode 12 that are independent of the ground potential, and by changing the detection distance between the two electrodes, a deviation in the detection amount due to a change in the environment such as rain can be obtained. While eliminating it, the detection accuracy of the human body can be improved. Further, as another technology, in a car lock device or the like, a lock sensor and a release sensor may be installed at different places in order to prevent a malfunction.

However, in such a conventional technique, there is a problem that the entire circuit including the detection unit becomes large-scale and complicated.
Therefore, there has been a demand for a circuit structure for a proximity sensor in which the detection unit and the circuit are not complicated and malfunctions are small.

International Publication WO2004 / 059343

An object of the present invention is to solve the problems in view of the problems that the proximity sensor often malfunctions and the circuit scale of the proximity sensor becomes large.

In order to solve the above problems, the proximity sensor according to the present invention uses a detection unit that detects the approach of a human body, a discrimination unit that discriminates a proximity state from the output of the detection unit, and another device based on the output from the discrimination unit. It consists of a device control unit to control, and the detection unit consists of a front surface side metal plate, a back surface side metal plate, a dielectric sandwiched between the two metal plates, a capacitor for removing noise, and a detection waveform. The discriminant unit consists of an amplification unit having a capacitor that smoothes the rectified waveform and a pulse shaping unit, and the signal from the detection unit is amplified by the amplification unit and pulse shaping is performed. It has a function of pulsed in a unit and used as an input signal to a device control unit equipped with a digital IC in the subsequent stage. The device control unit has a relay unit and uses the relay unit based on a signal from the pulse shaping unit in the discrimination unit. The means is to have a function of controlling ON / OFF of other devices.

Further, in the present invention, the back surface side metal plate has a larger surface area than the front surface side metal plate.

Further, in the present invention, the surface area of the back surface side metal plate is 2.5 times or more the surface area of the front surface side metal plate.

Further, in the present invention, the detection in the detection unit is performed by the capacitance value.

Further, in the present invention, the front surface side metal plate is a metal plate closer to the human body and is a plus side electrode, and the back surface side metal plate is a minus side electrode and is grounded to the ground. As a means.

Further, a shielded wire is used as the signal line from the front surface side metal plate and the back surface side metal plate, and the signal from the back surface side metal plate is conductive with the shield of the shielded wire.

Furthermore, the present invention is based on the fact that a third metal plate is held at a position closer to the human body than the surface-side metal plate, and a dielectric is provided between the surface-side metal plate and the third metal plate. ..

Furthermore, the present invention makes it a means that the device control unit switches ON / OFF of the device each time the human body approaches.

Further, in the present invention, the material of the dielectric is a petroleum-based resin as a means.

Further, the present invention uses the device control unit to turn on / off the commercial power.

According to the proximity sensor according to the present invention, the circuit of the detection unit for detecting the human body and the entire proximity sensor can be simplified, and malfunctions can be reduced. be.

It is a block diagram which shows the Example of the proximity sensor which concerns on this invention. It is a circuit diagram of the proximity sensor which concerns on this invention. It is a schematic diagram which shows the operation of the proximity sensor which concerns on this invention. It is a block diagram which shows the input part of the proximity sensor which concerns on this invention. It is a waveform figure which shows the signal of the proximity sensor which concerns on this invention. It is a schematic diagram which shows the detection range of the proximity sensor which concerns on this invention.

The greatest feature of the proximity sensor according to the present invention is that malfunctions and circuit complications can be eliminated by using a dielectric, a capacitor, and a diode in the detection unit.
Hereinafter, embodiments of the proximity sensor according to the present invention will be described with reference to the drawings.

The overall shape and the shape of each part of the proximity sensor according to the present invention are not limited to the examples described below, and are within the scope of the technical idea of the present invention, that is, a shape capable of exhibiting the same action and effect. And dimensions can be changed as appropriate.

The present invention will be described with reference to FIGS. 1 to 6. FIG. 1 is a block diagram showing an embodiment of a proximity sensor according to the present invention. FIG. 2 is a circuit diagram of a proximity sensor according to the present invention. FIG. 3A is a schematic view showing the operation of the proximity sensor according to the present invention. 3 (b) and 3 (c) are schematic views showing a terminal portion to which a metal plate is added to the detection portion. FIG. 4 is a configuration diagram showing an input unit of the proximity sensor according to the present invention. FIG. 5 is a waveform diagram showing a signal of the proximity sensor according to the present invention. FIG. 6 is a schematic view showing the detection range of the proximity sensor according to the present invention.

The proximity sensor 1 is a proximity sensor that detects a change in capacitance when a human body / object approaches, and is composed of a detection unit 10, a discrimination unit 30, and a device control unit 60. In addition to the human body, the reactants include metals, glass, resins, ceramics, fibers, paper, wood, and water.
The detection unit 10 is a part that detects a change in an electric signal due to a change in capacitance when a human body or the like approaches, and is a main part of the present invention. The determination unit 30 is a unit that amplifies the change in the signal detected by the detection unit 10 and converts the presence or absence of proximity into two values of HIGH / LOW of the pulse. The device control unit 60 is a part that controls the connected device 80 according to the value determined by the discrimination unit 30. In this embodiment, the operation of switching the ON / OFF state of the device is performed each time a person approaches.

The detection unit 10 includes a terminal unit 20 and a waveform shaping unit 11. This is a portion in which the voltage generated when a hand or the like is brought close to the terminal portion 20 is noise-removed and converted into direct current by the waveform shaping portion 11 to obtain a highly reliable signal.

The terminal portion 20 is composed of a front surface side metal plate 21, a dielectric 22, and a back surface side metal plate 23. As shown in FIG. 4, the structure is such that the dielectric 22 is sandwiched between the front surface side metal plate 21 and the back surface side metal plate 23. The front surface side metal plate 21 is arranged closer to the human body (the side closer to a person or an object), and the back surface side metal plate 23 is arranged so as to face each other. The front surface side metal plate 21 and the back surface side metal plate 23 are flat metal, and the area of the flat plate portion is about 1 to 30 square centimeters. The thickness is, for example, about 0.05 to 0.3 mm. As the material of the front side metal plate 21 and the back side metal plate 23, aluminum, a copper plate, or the like can be considered.

The dielectric 22 is for increasing the capacitance of the detection unit 10. It has a flat plate shape, and the shape of the flat plate portion is almost the same as that of the front surface side metal plate 21 and the back surface side metal plate 23. The thickness is, for example, about 2 to 10 mm. As the material, a member charged on the negative side such as polypurpyrene, vinyl chloride, styrene-based resin, and petroleum-based resin is used. The front surface side metal plate 21 is connected to the input of the waveform shaping unit 11, and the back surface side metal plate 23 is connected to the ground (− pole). When the human body approaches, the human body side of the dielectric 22 becomes negative, and the surface-side metal plate 21 in contact with the surface becomes a positive potential. By detecting this voltage, proximity is detected.

The signal from the terminal portion 20 to the waveform shaping portion 11 is connected by the shielded wire 27. The signal from the metal plate 23 on the back surface side is made conductive with the shield of the shielded wire 27. With such a configuration, the influence of noise can be reduced even if the terminal portion 20 is routed for a long time.

Further, with respect to the terminal portion 20, by making the surface area of the back surface side metal plate 23 wider than that of the front surface side metal plate 21, the back surface side metal plate 23 becomes the front surface side metal plate 21 of the downward electrical fluctuation. It is possible to suppress the wraparound of the metal plate 21 and reduce the noise of the metal plate 21 on the front surface in the direction of the metal plate 23 on the back surface. It is preferable that the surface area of the back surface side metal plate 23 is 2.5 to 3.0 times the surface area of the front surface side metal plate 21. With this configuration, even if the amount of capacitance differs depending on the installation location, stable detection can be performed. In addition, the influence of changes in temperature and humidity can be significantly reduced. It is also possible to use a long lead wire of 70 cm or more (FIG. 3 (a)).

Further, with respect to the terminal portion 20, the generated voltage can be increased by further adding a dielectric and a metal plate. For the combination of the front surface side metal plate 21, the dielectric 22, and the back surface side metal plate 23, another dielectric 22 is arranged on the front surface side metal plate 21 side, and the third metal plate 25 is arranged on the front side metal plate 21 side. do. In terms of cross section, the structure is such that the third metal plate 25, the dielectric 22, the front surface side metal plate 21, the dielectric 22, and the back surface side metal plate 23 are stacked in this order. The third metal plate 25 is electrically disconnected (FIG. 3 (b)).

Further, with respect to the terminal portion 20, the generated voltage can be increased by further adding a dielectric and a metal plate. For the combination of the front surface side metal plate 21, the dielectric 22 and the back surface side metal plate 23, a new dielectric 22 is arranged under the back surface side metal plate 23, and a third metal plate 25 is arranged under the new dielectric 22. Further, the dielectric 22 and the fourth metal plate 26 are arranged. The surface areas of the dielectric 22, the third metal plate 25, and the fourth metal plate 26 below the back surface side metal plate 23 are larger than those of the back surface side metal plate 23, and are, for example, about 2.5 to 3 times. The back surface side metal plate 23, the third metal plate 25, and the fourth metal plate 26 are electrically connected by an energizing body 29 (FIG. 3 (c)). In other words, a similar layer is added to the back side metal plate side, and the function of the back side metal plate can be increased.
By adopting such a configuration, it is possible to reduce the influence of changes in the environment such as temperature and humidity. It is possible to reduce the fluctuation of sensing due to the change of capacitance depending on the installation location. Moreover, since the influence of noise can be reduced, it can be installed remotely with a long lead wire.

Further, the structure may be such that the dielectric 22, the acrylic plate 24, the dielectric 22, and the third metal plate 25 are superposed on the surface side metal plate 21 (FIG. 3 (d)). At that time, it is conceivable that the newly added dielectric 22, the acrylic plate 24, the dielectric 22, and the third metal plate 25 are made larger than the size of the surface side metal plate 21. By adopting such an embodiment, the area corresponding to the human body H becomes large, and the detection performance can be further improved.

The waveform shaping unit 11 is a portion that removes noise from the signal of the metal plate 21 on the front surface side of the terminal unit 20 to convert an AC waveform into a DC waveform. The signal generated by the surface side metal plate 21 is an AC waveform. The voltage is limited by the Zener diode 12. The Zener voltage is about 3.2 to 5V. The capacitor 13 reduces unnecessary noise. The capacity of the capacitor 13 depends on the area of the surface side metal plate 21, but is, for example, about 30 to 1000 pF. If the capacitance of the capacitor 13 is large, the voltage waveform detected even when the human body approaches is small, and the capacitor 13 cannot be detected as a waveform. On the contrary, the smaller the value, the better the response, but if it is lost, noise cannot be removed and the reliability decreases. The diode 14 is for rectification.

The discrimination unit 30 includes an amplification unit 40 and a pulse shaping unit 50. The signal from the detection unit 10 is amplified by the amplification unit 40, pulsed by the pulse shaping unit 50, and used as an input signal to the device control unit 60 provided with the digital IC in the subsequent stage.

The amplification unit 40 includes a plurality of transistors 41, a resistor 42, and a capacitor 43. By combining a plurality of transistors 41 and resistors 42, the level of the signal input from the detection unit 10 can be amplified. By amplifying the signal, the amount of change in the signal at the time of proximity can be increased, so that the reliability of proximity discrimination can be improved. By using the capacitor 43, unnecessary noise can be further reduced.

The pulse shaping unit 50 detects the proximity, pulses the amplified signal, and further converts the proximity into a HIGH signal during detection and a LOW signal during non-detection. The signal level is adjusted by the operational amplifier 51 and the amplification width adjusting resistor 52. A comparator is composed of the operational amplifier 54 and the variable resistor 53, and all signals having a voltage higher than the voltage set by the variable resistor 53 become HIGH level signals, and signals having a voltage lower than the voltage set by the variable resistor 53 are signals. , All become LOW level signals. By adjusting the amplification width adjusting resistor 52 and the variable resistor 53, the amplification factor in the amplifier (including the comparator) can be changed, and the strength of the reaction can be changed.

Next, the high frequency component of the signal is removed by the discriminant value generation resistor 55 and the discriminant value generation capacitor 56. Without the discriminant value generation resistor 55 and the discriminant value generation capacitor 56, the toggle flip-flop 61 does not operate normally. By removing the high frequency component, a HIGH signal is always obtained when the proximity is detected, and a LOW signal is obtained when the proximity is not detected.
If the output from the pulse shaping unit 50 is used as it is, it is possible to perform an operation of turning on when proximity is detected and turning off when no proximity is detected.

The device control unit 60 mainly includes a toggle flip-flop 61, a relay unit 70, a DC power supply 66, and an AC100V 65.
The DC power supply 66 generates DC 5V power from AC100V65 by a switching regulator method.
A signal for switching HIGH / LOW is generated each time a proximity is detected by a signal from the pulse shaping unit 50, and the relay unit 70 is used to control ON / OFF of another device 80.
The AC100V65 is a commercial power source, and in this embodiment, the electric power is supplied to the device 80 (the lamp in the drawing), and the electric power is also supplied to the proximity sensor 1 via the DC power source 66.

The toggle flip-flop 61 is one type of flip-flop, and the signal from the pulse shaping unit 50 is received by the toggle flip-flop 61. For example, the output of the IC is inverted by the change that the signal from the pulse shaping unit 50 changes from LOW to HIGH. In other words, the output of the toggle flip-flop 61 can be inverted each time the proximity of the person changes from undetected to detected. One of the outputs of the toggle flip-flop 61 is connected to the ON display LED 63 via the transistor 62. When the output of the toggle flip-flop 61 is HIGH, the transistor 62 is turned on, a current flows through the ON display LED 63, and the ON display LED 63 emits light. Therefore, it can be easily confirmed whether the device is turned on or off.

The other output of the toggle flip-flop 61 is connected to the relay unit 70 via the transistor 64. The relay unit 70 is a general AC ON / OFF circuit including a photo triac 71, a triac 72, and a ZNR 73. When the dielectric 22 is turned on, the relay unit 70 is turned on, the electric power from the AC100V 65 is supplied to the device 80, and the device 80 operates. If the device 80 as shown is a lamp, it lights up.

The operation of the terminal portion 20 will be described with reference to FIG. 3A. The terminal portion 20 is composed of a front surface side metal plate 21, a back surface side metal plate 23, and a dielectric 22 sandwiched between the front surface side metal plate 21 and the back surface side metal plate 23. A capacitor is formed by a dielectric 22 sandwiched between two metal plates 21 and 23. The front surface side metal plate 21 is connected to the waveform shaping portion 11, and the back surface side metal plate 23 is grounded.

By bringing the human body H closer to the surface side metal plate 21 side, an induced voltage is generated in the dielectric 22. The front side metal plate 21 side of the dielectric 22 has a negative potential, and the back surface side metal plate 23 side has a positive potential. Then, the front surface side metal plate 21 has a positive potential, and the back surface side metal plate 23 has a negative potential. Since the back surface side metal plate 23 is grounded to the ground, it is zero volt, so that the front surface side metal plate 21 has a positive voltage value. It is possible to detect that the human body H is approaching by the processing after the connected waveform shaping unit 11.
That is, by using the dielectric 22, the amount of change in the potential accompanying the approach of the human body H can be increased, so that the human body H can be easily detected.

A numerical description of the present invention will be given with reference to FIG. The following mathematical formula shows the strength of the reaction when the human body H approaches, and the strength of the reaction is the magnitude of the voltage generated in the surface side metal plate 21.
(Equation 1) Reaction strength F = (S × D × H × d1 × d2) / C
S is the area of the wide surface of the terminal portion 20, D is the volume of the dielectric 22, H is the approaching speed of a human body or the like, d1 is the thickness of the front side metal plate 21, the back side metal plate 23, and d2 is the thickness of the dielectric 22. That's right. C is the capacitance of the capacitor 13.

The value of C is preferably 30 to 1000 pF.
When giving priority to the reaction strength F, it is better to set C to a value closer to 30 pF than 1000 pF. Further, in order to reduce the noise on the circuit, it is better to set the value closer to 1000pF than 30pF.

In formula 1, the reaction is larger when d2 is thicker than d1. Further, the reaction is larger when the d1 of the back metal plate 23 is thicker than that of the d1 of the front metal plate 21.

As shown in Equation 1, the reaction strength F increases as the approaching speed of the human body or the like increases, so that it can also be used as a proximity speed sensor.

The difference between the present invention and other methods will be described with reference to FIG.
FIG. 6A is a diagram showing a terminal portion 20 of the present invention and a detection region 28 showing a detection range of a human body or the like. FIG. 6B is a diagram showing a one-wire terminal portion 90 and a detection region 28 showing the detection range thereof as an example of a conventional sensor.

The terminal portion 20 has a three-layer structure including a front surface side metal plate 21, a dielectric 22, and a back surface side metal plate 23. The front surface side metal plate 21 is a plus side electrode, and the back surface side metal plate 23 is a minus side electrode. The metal plate 23 on the back surface side is grounded to the ground. Even if a human body or the like approaches from the back surface side metal plate 23, the fluctuation is absorbed by the back surface side metal plate 23 grounded to the ground, so that it is not detected. Therefore, the detection region 28 extends only to the surface side metal plate 21 side (FIG. 6A).

The one-wire terminal portion 90 has a three-layer structure including a one-wire front metal plate 91, a dielectric 92, and a one-wire back metal plate 93. The 1-wire type front side metal plate 91 is a positive side electrode, and the 1-wire type back side metal plate 93 is not electrically connected. Even if a human body or the like approaches from the 1-wire type front side metal plate 91 side or from the 1-wire type back surface metal plate 93 side, a signal is generated on the 1-wire type front side metal plate 91. Therefore, the detection region 28 extends to both the 1-wire type front surface side metal plate 91 side and the 1-wire type back surface metal plate 93 side (FIG. 6B).
Since the detection area 28 is wide, the one-wire terminal portion 90 also picks up noise. Therefore, it cannot be placed on a wooden table or the like. Since there is a lot of noise, the lead wire cannot be lengthened. Poor stability when moving the installation location. It will be affected if there is metal nearby. There are problems such as.

On the other hand, in the terminal portion 20 of the present invention, even if it is arranged on a table such as wood, the influence of the table is blocked by the metal plate 23 on the back surface side, so that there is no influence. Since the terminal portion 20 itself has directivity, the amount of noise can be reduced, and the lead wire can be lengthened by conducting the shield of the shielded wire 27 with the metal plate 23 on the back surface side by using the shielded wire 27. In addition, the stability is good when the installation location is moved, and the influence can be reduced even if there is metal nearby.
As described above, the two-wire system of the present invention is superior to the one-wire system.

Next, each signal waveform of the present invention will be described with reference to FIG. The signals at the locations indicated by A to F on the circuit diagram of FIG. 2 are shown in FIG. All waveforms are voltage waveforms, and the horizontal axis is time. The voltage waveform when the human body H is repeatedly moved from the state where the human body H is separated from the terminal portion 20 to the state where the human body H is approached and separated from the terminal portion 20 is shown.

When the human body H is separated from the terminal portion 20, noise is carried on A, which is the output of the terminal portion 20. The noise is due to the capacitance near the terminal portion, radio waves, electromagnetic waves including lightning, and the like.
When the human body H approaches the terminal portion 20, an induced voltage is generated in the dielectric 22 when the human body H approaches. The generated signal is sent to the waveform shaping unit 11 through the shielded wire 27. The generated voltage is alternating current and is accompanied by some noise (waveform A). It is smoothed by the Zener diode 12, the capacitor 13, and the resistor 42 of the waveform shaping unit 11, and noise is also reduced (stabilized) (waveform B). Waveform shaping and noise removal are efficiently performed by the Zener diode 12 and the capacitor 13. Waveform B is direct current.

The waveform is amplified by a multi-stage transistor amplifier circuit in which a plurality of transistors 41 of the amplification unit 40 and the transistors 41 are combined (waveform C).
Further, it is amplified to the vicinity of the dynamic range by the multi-stage transistor amplifier circuit by the transistor 41 and the resistor 42, and the waveform becomes almost a pulse (waveform D).

It is further amplified by the operational amplifier 51 and the amplification width adjusting resistor 52 of the pulse shaping unit 50, and becomes a HIGH / LOW binary pulse by the comparator formed by the operational amplifier 54 and the variable resistor 53. The HIGH / LOW threshold is determined by the voltage determined by the variable resistor 53. Subsequent discrimination value generation resistors 55 and discrimination value generation capacitors 56 remove high-frequency components. The values of the discriminant value generation resistor 55 and the discriminant value generation capacitor 56 are set to values that can sufficiently remove the frequency of the waveform generated at the terminal portion 20. The waveform from which the high-frequency component is removed by the discrimination value generation resistor 55 and the discrimination value generation capacitor 56 becomes a HIGH level waveform when the human body H is in close proximity and a LOW level waveform when the human body H is remote (waveform E). By using this waveform, it is possible to make a switch that operates when it is close and does not operate when it is remote.

The toggle flip-flop 61 of the device control unit 60 provides a waveform that is inverted at each rising edge of the waveform E (waveform F). In other words, the HIGH / LOW is reversed each time the human body H approaches. Therefore, it is turned on when the hand is brought closer, and turned off when the hand is once moved away and the hand is brought closer again.
The waveform F enters the relay unit 70 via the transistor 64 and controls ON / OFF of the home appliance used at 100V. Further, by turning on the ON display LED 63 via the transistor 62, it is possible to confirm at a glance whether the waveform F is HIGH or LOW, so that the control of the device becomes easy.

As described above, according to the present invention, the circuit of the detection unit for detecting the human body and the entire proximity sensor can be simplified, and malfunctions can be reduced, which is an excellent effect. be.

In the present invention, the detection voltage can be increased by using a dielectric material in the detection unit. Further, by arranging a diode that rectifies in the direction of the amplification section between the metal plate to be detected and the amplification section and a capacitor on the amplification section side of the diode, noise of the signal obtained by the metal plate can be removed. .. With these configurations, the present invention has a higher detection level than the conventional proximity sensor and can be made resistant to noise.

Further, since the present invention reacts through glass, it can also be used for crime prevention. It is also possible to react by placing vinyl chloride or placing wood, resin, or ceramics on top of the vinyl chloride.

Further, although the present invention has one detection signal line, it is simple and can be used for any switch by adopting a structure in which ground signal lines are arranged in parallel.

Since the proximity sensor according to the present invention is a simple proximity sensor with few malfunctions and can be used in any device that can be turned ON / OFF, it is understood that it has great industrial applicability.

1 Proximity sensor 10 Detection unit 11 Wave shape shaping unit 12 Zener diode 13 Capacitor 14 Diode 20 Terminal part 21 Front side metal plate 22 Dielectric 23 Back side metal plate 24 Acrylic plate 25 Third metal plate 26 Fourth metal plate 27 Shield Line 28 Detection area 29 Energizer 30 Discrimination unit 40 Amplification unit 41 Transistor 42 Resistance 43 Capacitor 50 Pulse shaping unit 51 Operational amplifier 52 Amplification width adjustment resistance 53 Variable resistance 54 Operational amplifier 55 Discrimination value generation resistance 56 Discrimination value generation capacitor 60 Equipment control unit 61 Toggle flip flop 62 transistor 63 ON indicator LED
64 Transistor 65 AC100V
66 DC power supply 70 Relay section 71 Photo triac 72 Triac 73 ZNR
80 Equipment 90 1-wire terminal 91 1-wire front metal plate 92 Dielectric 93 1-wire back metal plate H Human body

Claims (10)

It consists of a detection unit that detects the approach of the human body, a discrimination unit that discriminates the proximity state from the output of the detection unit, and a device control unit that controls other devices by the output from the discrimination unit.
The detection unit has a front side metal plate, a back side metal plate, a dielectric sandwiched between the two metal plates, a capacitor for removing noise, and a diode for rectifying the detection waveform.
The discrimination unit consists of an amplification unit having a capacitor that smoothes the rectified waveform and a pulse shaping unit. The signal from the detection unit is amplified by the amplification unit, pulsed by the pulse shaping unit, and then digitally performed in the subsequent stage. It has a function to be an input signal to the device control unit equipped with an IC.
The device control unit is a proximity sensor circuit having a relay unit and having a function of controlling ON / OFF of another device by using the relay unit based on a signal from the pulse shaping unit in the discrimination unit.
The proximity sensor circuit according to claim 1, wherein the back surface side metal plate has a larger surface area than the front surface side metal plate. The proximity sensor circuit according to claim 2, wherein the surface area of the back surface side metal plate is 2.5 times or more the surface area of the front surface side metal plate. The proximity sensor circuit according to any one of claims 1 to 3, wherein the detection by the detection unit is performed by a capacitance value. Claim 1 is characterized in that the front surface side metal plate is a metal plate closer to the human body and is a plus side electrode, and the back surface side metal plate is a minus side electrode and is grounded to the ground. The proximity sensor circuit according to any one of claims 4. From claim 1, a shielded wire is used as the signal line from the front surface side metal plate and the back surface side metal plate, and the signal from the back surface side metal plate is conductive with the shield of the shielded wire. The proximity sensor circuit according to any one of claim 5. Claims 1 to 6 are characterized in that a third metal plate is held at a position closer to the human body than the surface-side metal plate, and a dielectric is provided between the surface-side metal plate and the third metal plate. The proximity sensor circuit according to any one of. The proximity sensor circuit according to any one of claims 1 to 7, wherein the device control unit switches ON / OFF of the device each time the human body approaches. The proximity sensor circuit according to any one of claims 1 to 8, wherein the material of the dielectric is a petroleum-based resin. The proximity sensor circuit according to any one of claims 1 to 9, wherein the device control unit turns on / off commercial power.

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