JP2001255381A - Capacitance type detector and self diagnostic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a detector using a noncontact sensor capable of sufficiently securing a detection area. SOLUTION: The capacitance type detector is provided with a first electrode 10 and a second electrode 11 arranged facing the first electrode 10 and a detection circuit for detecting the variation ΔC of the capacitance between the first electrode 10 and the second electrode 11. It can be used in industrial fields such as separation of a aluminum cans and of special materials, the detection of entry of men and automatic opening and closing of elevator doors.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitance type detection device provided with a capacitance type sensor and a self-diagnosis device for the capacitance type detection device.

[0002]

2. Description of the Related Art Various types of detection devices using sensors are known. For example, an optical sensor is used as a safety device for detecting whether a human hand approaches a production machine or the like. An optical sensor has the advantage that non-contact detection is possible.

[0003]

However, since the detection area of the optical sensor is small, an attempt to expand the detection area requires a large number of optical sensors, which is problematic in terms of cost. The present invention has been made in view of the above circumstances, and an object thereof is to provide a detection device using a non-contact sensor capable of sufficiently securing a detection area, and a self-diagnosis device for the detection device. It is.

[0004]

According to the present invention, there is provided a capacitance type detecting device comprising: a first electrode; a second electrode disposed opposite to the first electrode; First
And a detection circuit for detecting a change in capacitance between the first electrode and the second electrode.

The sensor used in this detection device detects a change in capacitance between the first electrode and the second electrode. When a person or an object enters between the first electrode and the second electrode, the capacitance changes. Therefore, by detecting this by a detection circuit, the intrusion of a person or an object can be detected. That is, it is a non-contact type sensor.
Further, by making the first electrode and the second electrode sufficiently large, the detection area can be easily enlarged.
As a result, it is possible to provide a detection device using a non-contact sensor capable of sufficiently securing a detection area.

[0006] As a first preferred embodiment of the present invention, there is provided a transporting means for transporting a metal object and a non-metallic object along a transport path in a mixed state. The first electrode and the second electrode are disposed, and the detection circuit is configured to be capable of selecting a metal object from a mixed object group.

[0007] For example, transport means such as a transport conveyor,
Aluminum cans (metal objects), bottles, PET bottles (non-metal objects) are transported in a mixed state.
By passing between the second electrodes, it is possible to select only aluminum cans. This is based on the property that the relative permittivity of an aluminum can is different from other nonmetallic objects. Thereby, refuse can be reliably separated.

According to a second embodiment of the present invention, there is provided a conveying means for conveying a plurality of objects having different relative dielectric constants along a conveying path in a state where the objects are mixed, and the conveying means is provided so as to sandwich the conveyed object group. A first electrode and a second electrode are provided, and the detection circuit is configured to be capable of selecting an object having a specific dielectric constant from a mixed object group.

This is a modification of the first embodiment, and focuses on the property that the relative permittivity is different when the material is different. This makes it possible not only to separate metals but also to sort only a specific resin material from a mixture of various types of resin materials. This makes it possible to provide a capacitance type detection device that can be applied to not only separation of dust but also, for example, other various uses.

As a third embodiment of the present invention, the first electrode and the second electrode are arranged on both sides in the width direction or the vertical direction of the entrance / exit portion of the building, and the detection circuit comprises the entrance / exit portion. And a device configured to detect intrusion of a person or an object from the device.

According to this configuration, the veranda of the building,
It is possible to reliably detect the intrusion of a thief or a robber who intrudes from doorways such as doors and windows. Since the relative permittivity of a person is higher than the relative permittivity of air, it can be easily detected.

As a fourth embodiment of the present invention, the first electrode and the second electrode are arranged on both sides in the width direction or the vertical direction of a door of an elevator or the like, and the detection circuit is provided in front of the door. One that is configured to be able to detect the presence of a person is included.

According to this configuration, when a person comes in front of a door of an elevator or the like, the presence of the person can be detected, the elevator can be moved to the floor, and the door can be automatically opened. . Therefore, by using this capacitance type detection device, it is possible to provide an elevator system which is very convenient for a disabled person or the like.

According to a fifth embodiment of the present invention, the detection circuit is configured to be capable of detecting the amount of a conductor that has entered between the first electrode and the second electrode. Can be

This configuration detects the amount of entry of an object such as a conductor that has entered between the first and second electrodes.
Because the amount of change in capacitance differs depending on the amount of entry of the object,
The entering amount can be obtained by the detection circuit. This capacitance detection device can be used as a position sensor, and can be used for various applications.

As a sixth embodiment of the present invention, a first electrode and a second electrode are arranged on both side walls of a toilet seat, and the detection circuit determines whether or not a person is sitting on the toilet seat. One that detects whether or not.

According to this configuration, when a person enters the toilet and sits on the toilet seat, the person is detected by a change in capacitance. As an application in this case, for example, when there is an elderly person living alone, it is possible to detect that a person has entered the toilet at the monitoring center and to monitor the time in the toilet. Then, when it is determined that the time in the toilet is longer than usual, it is possible to take prompt action assuming that some abnormality has occurred.

According to a seventh embodiment of the present invention, the first electrode and the second electrode are disposed on both sides of a passage in a building, and the detection circuit includes a first electrode and a second electrode. In this case, it is detected that a person has entered between the electrodes, thereby turning on or off the illumination.

According to this configuration, when a person enters between the first and second electrodes, the illumination can be automatically turned on. In other words, it is not necessary to turn on the illumination when there is no intrusion of a person, so that unnecessary power consumption can be prevented and the trouble of lighting operation of the illumination can be saved. Further, the lighting may be turned off instead of turning on the lighting.

A self-diagnosis device according to the present invention is a self-diagnosis device for performing a self-diagnosis of any one of the above-mentioned capacitance type detection devices, wherein a first electrode and a first electrode are disposed so as to face the first electrode. A capacitance sensor comprising a second electrode to be
In order to perform a self-diagnosis, a simulation signal supply unit that supplies a simulation signal for operating the capacitance sensor, a comparison signal output unit that outputs a comparison signal having a preset width, and the simulation signal A comparison determination unit that compares the width of the sensor output signal output from the capacitance sensor with the width of the comparison signal; and, as a result of the comparison, when the width of the sensor output signal is shorter than the width of the comparison signal. To
And an error signal output section for outputting an error signal.

The operation and effect of the above configuration are as follows. (1) A simulation signal for operating the capacitance sensor is supplied. This is, for example, provided by providing an auxiliary electrode between the first electrode and the second electrode, and by operating this auxiliary electrode by a simulated signal, an object or a human body is inserted between the electrodes. A state can be created. Alternatively, a configuration in which a simulated object is inserted between the first electrode and the second electrode may be adopted. (2) The capacitance sensor outputs a sensor output signal having a certain width according to the simulation signal. (3) On the other hand, a comparison signal having a width set in relation to the supply of the simulation signal is output. (4) Compare the width of the comparison signal with the width of the sensor output signal. (5) If the width of the sensor output signal is shorter than the width of the comparison signal, an error signal is output.

This is based on the technical idea that if the capacitance sensor or the like is normal, a sensor output signal having a width equal to or larger than a predetermined width should be output. The case where the width is shorter than the width of the comparison signal includes, of course, the case where no sensor output signal is output. As described above, it is possible to determine whether an error has occurred based on the width of the sensor output signal.

[0023]

Preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating a detection principle of a capacitance type detection device using a capacitance sensor. FIG.
1A, a first electrode 10 and a second electrode 11 are arranged so as to face each other. Under normal conditions,
The capacitance between the first and second electrodes 10 and 11 is Co. When a person or an object enters between these electrodes, the capacitance becomes Co + ΔC. A first guard plate 12 is provided on the rear side of the first electrode 10, and a second guard plate 13 is provided on the rear side of the second electrode 11. The wiring from the first electrode 10 is guarded by a first guard cable 14, and the wiring from the second electrode 11 is guarded by a second guard cable 15.

The reason why the first and second guard plates 12 and 13 are provided is as follows. That is, the first and second electrodes 1
The area between 0 and 11 is the original detection area, but actually, the lines of electric force are on the back side of the electrodes 10 and 11 (opposite to the detection area), from the back side of one electrode to the back side of the other electrode. Therefore, an electric field is formed outside the original detection area. Then, since the capacitance changes even when a person or an object passes behind the electrodes 10 and 11, this causes erroneous detection. Therefore, by providing the first and second guard plates 12 and 13 as described above,
No electric field is formed on the back side of each of the electrodes 10 and 11,
False detection can be prevented.

Returning to FIG. 1A, e1 and e2 are measurement power supplies, CB is a balanced capacitance, and Zi is an input impedance of the amplifier. A detector 16 (FIG. 1) is connected to the output of the amplifier.
(See (b)). One end of the first guard cable 14 is connected to the first guard plate 12, and the other end is grounded. One end of the second guard cable 15 is connected to the second guard plate 13, and the other end is grounded via the other end of the first guard cable 14. An auxiliary electrode 40 for performing self-diagnosis is provided.
Numeral 1 is for making this auxiliary electrode 40 function.
This will be described later.

FIG. 1B shows the principle of the detection circuit. The detection circuit uses an impedance bridge, and two sides of the basic four-sided bridge are connected to a measuring power source e.
1, e2, and the other two sides are the detected capacitance Co and the balanced capacitance CB.

<Equivalent Circuit> FIG. 2 is a diagram showing a configuration of an equivalent circuit of the capacitance type detection device shown in FIG. Co is
This is the capacitance when no person or object enters between the first and second electrodes 10 and 11. ΔC is a change in capacitance when a person or an object enters between the first and second electrodes 10 and 11. C1 is the first guard cable 14
And the capacitance between the first electrode 10 and the first guard plate 12. C2 is the capacitance between the second guard cable 15, the second electrode 11, and the second guard plate 13.
CB is an equilibrium capacitance, and CB = Co × (e1 / e
2). Ze1 is the internal impedance of the measurement power supply e1. Ze2 is the internal impedance of the measurement power supply e2.

When the measurement power supplies e1 and e2 are turned on in a state where only air exists between the first and second electrodes 10 and 11,
When the voltage of the measurement power supply e1 is sufficiently larger than Ze1 × i1, the current flowing from the measurement power supply e1 through the capacitor C2 hardly flows through the impedance Zi and can be ignored. The current flowing through the capacitor Co is divided into a capacitor C1 and an impedance Zi. At this time, 1 / (ωC
When 1) is sufficiently larger than Zi, most of the current i1 flows through the impedance Zi. From the measurement power supply e2,
When the current i2 flowing through the capacitor CB is equal to the current i1 and the phase difference is 180 °, the current flowing through the impedance Zi becomes zero.

Now, between the first and second electrodes 10 and 11,
When a person or an object enters, the capacitance Co changes by an amount corresponding to the relative permittivity. Assuming that this change is ΔC, the current i1 changes by e1ωΔC, the current flows through the impedance Zi, and is detected as a signal. In the detection circuit shown in FIG. 2, the capacitance between the first and second electrodes 10 and 11 and the first and second guard plates 12 and 13 and the capacitance of the wiring (coaxial cable), It is hardly affected by other disturbances, and it is possible to accurately detect a change in capacitance between the first and second electrodes 10 and 11. In the figure, Δ
C ′ indicates a change in capacitance when the auxiliary electrode 40 is operated as described later.

<Application Example 1> Examples in which the capacitance detection device according to the present invention is applied to various industrial fields will be described. In each application example described below, only the arrangement of the first and second electrodes 10 and 11 is basically shown.

FIG. 3 shows an apparatus for separating aluminum cans (steel cans) K conveyed by the belt conveyor 17 from bottles and PET bottles. It is based on the principle that the relative permittivity of aluminum is different from the relative permittivity of bottles and PET bottles. First and second electrodes 10 and 11 are arranged so as to sandwich an object such as an aluminum can to be conveyed. When it is detected that the aluminum can K has come between the first and second electrodes 10 and 11, the cylinder 18 is operated and the aluminum can K is collected in the collection device 19. In the example of FIG. 3, the first and second electrodes 10 and 11 are disposed on both left and right sides of the transport path, but the first and second electrodes 10 and 11 are located on the upper and lower sides of the transport path, respectively.
The second electrodes 10 and 11 may be arranged. Also, the first, so as to sandwich an object such as an aluminum can from an oblique direction
The second electrodes 10 and 11 may be provided.

As another modification, conversely, only bottles and PET bottles may be separated and collected. When various types of materials are mixed and conveyed while being mounted on a belt conveyor, it is possible to provide a detection device capable of separating only specific materials. In the example of FIG. 3, the metal and the non-metal are separated. However, the configuration may be such that only a specific non-metal material can be separated from the non-metal. For example, the relative permittivity of Teflon (registered trademark) is 2.0, the relative permittivity of PET is 3.1 to 3.2,
Since the relative dielectric constant of soft vinyl chloride is 5.0 to 9.0, it is possible to configure a detection device capable of separating only a specific resin by focusing on the difference in these relative dielectric constants.

<Application Example 2> FIG. 4 shows that first and second electrodes 10 and 11 are arranged on both sides in the width direction of a handrail 20 of a veranda (corresponding to an entrance) of a building such as an apartment or an apartment. It is an example. This makes it possible to detect intrusion of a thief. If there is a resident in the room, the detection circuit is deactivated and the detection circuit is activated when the resident goes to bed or goes out. It is also possible to connect the detection circuit to a monitoring center and to constantly monitor it. It is preferable that the electrodes are not exposed but protected by a cover member or the like.

In addition to the veranda, it may be provided at the entrance, entrance, window, gate, chimney or other entrance. It may be provided at an entrance (door) of a specific room in a house.

<Application Example 3> FIG. 5 shows an example in which first and second electrodes 10 and 11 are arranged on both sides of an elevator 21 in the vertical direction. When a person comes in front of the door, the capacitance changes,
Detect that a person has come. This will automatically open the door if the elevator is already at that floor. People,
It is not necessary to press the push button. If the elevator is on another floor, it can be automatically moved to that floor. Such a detection device, for the handicapped, etc.,
There is an advantage that you do not have to lean out and press the push button. The first and second electrodes 10,
By arranging 11, it is not necessary to install an obstacle around the door 21 of the elevator 21, and it is not necessary to impair the appearance.

The first and second electrodes 10 and 11 may be arranged not on the upper and lower sides of the door 21 but on both sides in the width direction of the door 21. In this case, the height of each of the electrodes 10 and 11 is set to be a predetermined height from the floor surface. By setting from the floor position, not only adults but also children can be detected. As a modification, the present invention can be applied not only to an elevator but also to an automatic door of a department store or a building.

<Application Example 4> FIG. 6 shows an apparatus for detecting that an object such as a conductor 22 has entered between the first electrode 10 and the second electrode 11. The amount of change in the capacitance differs depending on the amount of the conductor 22 entering. Therefore, the position of the conductor 22 can be detected by detecting this change.
6 can be applied to various industrial fields as a position sensor.

<Application Example 5> FIG. 7 shows first and second electrodes 10, 1 on the left and right wall surfaces of a toilet seat 23 in a Western-style toilet.
This is an example in which 1 is arranged. A person enters the toilet and toilet seat 2
3, the presence of a person can be detected. As an application in this case, for example, when there is an elderly person living alone, the monitoring center detects that a person has entered the toilet and also monitors the time in the toilet. If it is determined that the time spent in the toilet is longer than usual, it is possible to take a countermeasure assuming that some abnormality has occurred. It is particularly necessary for toilets in hospitals and facilities.
It is preferable that the first and second electrodes 10 and 11 are embedded in the inside of the wall surface, so that the appearance is not impaired.

The first and second electrodes 10 and 11 may be arranged on the upper and lower wall surfaces (floor surface and ceiling surface) instead of the left and right wall surfaces. As a modified example, the present invention can be applied to a bathroom other than a toilet. For example, by arranging the first and second electrodes on a pair of opposed wall surfaces in the bathroom, it is possible to monitor the staying time of a person in the bathroom. Also, by arranging the first and second electrodes in the bathtub, it is possible to monitor the time during which a person is immersed in the bathtub. This is expected to prevent accidents from occurring.

<Application Example 6> FIG. 8 shows a configuration example in which first and second electrodes 10 and 11 are arranged on the left and right sides of a passage such as a corridor in a room. And automatically turns on the lighting 24. According to this detection device,
When there is no human intrusion, it is not necessary to turn on the lighting, so that unnecessary power consumption can be prevented, and the trouble of turning on the lighting can be saved.

The first and second electrodes 10 and 11 may be arranged on both upper and lower sides (floor surface and ceiling surface), not on both right and left sides of the passage. As a modified example, there is a configuration in which the lighting is automatically turned on when a person enters the entrance of the house. Another example is a configuration in which the lighting is automatically turned on when a person enters a toilet, a bathroom, or another room. Further, the present invention can also be applied to a case where the lighting is turned off instead of turning on the lighting.

<Self-diagnosis device> Next, a self-diagnosis device of a detection device using the capacitance sensor according to the present invention will be described. FIG. 9 is a sequence diagram showing a self-diagnosis circuit for performing self-diagnosis of the capacitance type detection device.
It can be composed of electrically controllable parts and devices such as a controller and a personal computer. FIG. 10 is a diagram showing a time chart and an auxiliary electrode driving unit corresponding to the sequence diagram of FIG. In this self-diagnosis device, an auxiliary electrode 40 is provided so as to face either one of a first electrode 10 and a second electrode 11 (capacitance sensor), and this is used for generating a simulation signal to be described later. Relay R2 (switch 41 in FIG. 1)
Is equivalent to ), Switching is performed periodically to check whether the desired detection can be performed.

In FIG. 9, a cycle timer T1 for setting a cycle for performing self-diagnosis and a B contact of the cycle timer T1 are connected in series, and a simulation for outputting a simulation signal connected in parallel with the cycle timer T1. Signal timer T
2, and a self-diagnosis timer T3 for setting a time for performing self-diagnosis, which is also connected in parallel with the period timer T1.

The sensor output relay R1 is connected in series with the SW that is turned on by the operation of the capacitance sensor. That is, the sensor output relay R1 is excited (turned on) when the switch is turned on. Sensor output relay R1 is O
The time to become N is the width of the sensor output signal (r in FIG. 10).
1, r2, r3). Simulated signal timer T
2 and the simulation signal generation relay R2 are connected in series. That is, a simulation signal for operating the sensor is generated for a time t2 set by the simulation signal timer T2 (see FIG. 10). The B contact of the self-diagnosis timer T3 and the self-diagnosis signal output relay R3 are connected in series. Thus, the time t3 set by the self-diagnosis timer T3 is set as the time for performing the self-diagnosis.
The time t3 is set so as to cover the width of the sensor output signal in consideration of the width of the sensor output signal.

The A contact of the sensor output relay R1 and the width determination timer T4 are connected in series. Width judgment timer T4
Is provided for outputting a comparison signal having a preset width. By comparing the width of the comparison signal with the width of the sensor output signal, whether or not an error has occurred in the capacitance sensor or the like is determined. Is determined.

The A contact of the width determination timer T4 and the width determination relay R4 are connected in series. Then, the comparison signal is output by the width determination relay R4 for a time t4 set by the width determination timer T4 (see FIG. 10).
A contact of width determination relay R4 and sensor output relay R
1, an A contact, a simulated signal generation relay R2 B contact,
A normal signal generation relay R5 is connected in series, and the A contact of the width determination relay R4 and the sensor output relay R1
And the A contact of the normal signal generation relay R5 are connected in parallel. That is, the relay R5 is turned on by turning on the relays R1 and R4 and turning off the relay R2.

The A contact of the self-diagnosis signal output relay R3 and the error signal generation relay R6 are connected in series.
The relay R3 and the A contact of the normal signal generation relay R5 are connected in parallel. Normal detection signal generation relay R
7, the B contact of the self-diagnosis signal output relay R3, and the A contact of the sensor output relay R1 are connected in series.
The A contact of the relay R3 is also connected in series with the relay R7.

<Time chart of self-diagnosis circuit> FIG.
(B) is a schematic diagram of a self-diagnosis device using a capacitance sensor including a first electrode 10 and a second electrode 11. An auxiliary electrode 40 functioning as a simulated human body (or a simulated object) is connected to a detection circuit via a contact of a simulated signal generation relay R2. The self-diagnosis circuit 5 is configured based on the sequence diagram shown in FIG. The capacitance sensor detects that the capacitance between the first and second electrodes 10 and 11 changes due to the entry of an object or a person, and outputs an alarm signal or causes a predetermined operation. I do. In other words, the self-diagnosis of the capacitance sensor is performed by operating the auxiliary electrode 40 to forcibly create the same state as when an object or a person has entered between the first and second electrodes 10 and 11. It can be carried out.

Therefore, a simulation signal (R2) as shown in FIG. 10A is periodically generated from the self-diagnosis circuit 5 by the simulation signal generation relay R2. The period is indicated by t1, which is set by a period timer T1. The width of the simulation signal (R2) is indicated by t2, and is set by the simulation signal generation relay R2. In FIG. 10A, three cycles are shown for convenience of explanation. In the first cycle, when the output from the sensor is normal, in the second cycle, the output from the sensor is abnormal (the output signal width is small). , The third cycle indicates the case where the output from the sensor is abnormal (no output signal).

<Normal case> By the simulation signal (R2),
The auxiliary electrode 40 operates to change the capacitance between the first and second electrodes 10 and 11 (corresponding to ΔC ′ in FIG. 2). This is detected by a detection circuit, and an output signal (R1) is output by a sensor output relay R1. FIG.
As shown in FIG. 3, the simulation signal (R2) and the output signal (R1)
There is a time lag of Δt, which is due to a delay in conversion by the A / D converter and the like.
This is a slight amount on the order of seconds. (FIG. 10 is exaggerated.) If the sensor or the like is normal, the output signal (R1) is a pulse-like signal having a width tr1.

At the same time as the output signal (R2), the comparison signal (R4) is output from the width determination relay R4. The width of the comparison signal (R4) is set to be t4 by the width determination timer T4. The comparison signal (R4) is normally at the H level (ON), and the L level (OFF) is active. When the width determination time t4 has elapsed, the output signal (R2) is at the L level and the comparison signal (R
If 4) is at the H level and the output signal (R1) is at the H level, the normal signal generation relay R5 is turned on to generate the H level normal signal (R5). That is, if the width tr1 of the output signal (R1) is larger than the width t4 of the comparison signal (R4), it is determined that the sensor and the like are normal. The output signal (R1) changes to the L level after the time corresponding to the width tr1 has elapsed, but since the relay R5 is self-held by the A contact of the relay R5, the normal signal (R5) is held as it is at the H level. Is done. The self-holding is released when the simulation signal (R2) rises in the next cycle (see FIG. 9).

The error signal generating relay R6 outputs an L-level error signal (R6) when an error occurs in a sensor or the like as a result of the self-diagnosis. While the signal (R3) is being generated, no error signal is output, and the error signal (R6) is not output if the H-level normal signal (R5) is output even after the self-diagnosis period has elapsed. (See FIG. 10).

The normal detection signal generation relay R7 outputs an L level normal detection signal (R7) in a normal use state where self-diagnosis is not performed. Since the relay R7 is connected in series with the A contact of the self-diagnosis signal output relay R3, the L-level normal detection signal (R7) during the self-diagnosis period.
Is not output. As shown in FIG. 10, when there is an output signal (R1) indicated by r2, the normal detection signal (R
7) becomes L level.

Although not shown, the error signal (R6)
Is output, an alarm is issued to inform the operator. An alarm is also issued when the normal detection signal (R7) is output.

<Abnormal Case> Next, it is assumed that there is an abnormality in the capacitance sensor or the like and the width of the output signal (R1) is as small as tr3. This width tr3 is smaller than the width of the set comparison signal t4. Therefore, when the self-diagnosis period t4 has elapsed, the relay R1 has already been turned off,
As a result, the normal signal generation relay R5 is not turned on. Therefore, the normal signal (R5) is not output. When the self-diagnosis period t3 has elapsed since the relay R5 is not turned on, the error signal generating relay R6 is turned off. That is, an L-level error signal (R6) is generated. When the capacitance sensor is abnormal and no output signal R1 is output, the same result as in the case where the width is small is obtained.

As described above, the relay R2 and the timer T2
Functions as a simulation signal supply unit, the relay R4 and the timer T4 function as comparison signal output units, and the relays R1, R
2, R4 and R5 function as comparison and determination units, and the relay R
3, R5 and R6 function as error signal output units, and the timer T3 and the relay R3 function as self-diagnosis signal output units.

As described above, the capacitance type detection device according to the present invention can be used in various industrial fields, and can be made to have high added value by having a self-diagnosis function.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a detection principle of a capacitance-type detection device using a capacitance sensor.

FIG. 2 is a diagram showing details (equivalent circuit) of the detection circuit of FIG. 1;

FIG. 3 is an application example in which the present invention is used for sorting aluminum cans.

FIG. 4 is an example of application of the present invention to a veranda of a building.

FIG. 5 is an example of application of the present invention to an elevator.

FIG. 6 is an application example using the present invention as a position sensor.

FIG. 7 is an application example in which the present invention is used in a toilet room.

FIG. 8 is an application example in which the present invention is used for automatic lighting of lighting in a passage.

FIG. 9 is a sequence diagram showing a self-diagnosis circuit for performing self-diagnosis of the capacitance type detection device.

10 is a diagram showing a time chart and an auxiliary electrode driving unit corresponding to the sequence diagram of FIG. 9;

[Explanation of symbols]

 Reference Signs List 10 first electrode 11 second electrode Co capacitance ΔC change in capacitance e1 measurement power supply e2 measurement power supply

Claims (9)

[Claims] A first electrode; a second electrode disposed opposite to the first electrode; and a detection circuit for detecting a change in capacitance between the first electrode and the second electrode. And a capacitance-type detection device. 2. A method according to claim 1, further comprising: transport means for transporting the metal object and the non-metal object along a transport path in a mixed state, wherein the first electrode and the second electrode sandwich the object group to be transported. The capacitance detection device according to claim 1, wherein the detection circuit is configured to be able to select a metal object from a mixed object group. 3. A transport means for transporting a plurality of objects having different relative dielectric constants along a transport path in a mixed state, wherein the first electrode and the second electrode are sandwiched by the transported object group. The capacitance type according to claim 1, wherein electrodes are arranged, and the detection circuit is configured to be capable of selecting an object having a specific relative permittivity from a mixed object group. Detection device. 4. The first electrode and the second electrode are arranged on both sides in a width direction or a vertical direction of an entrance / exit portion of a building,
2. The detection circuit according to claim 1, wherein the detection circuit is configured to detect intrusion of a person or an object from the entrance / exit portion. 3.
The capacitance-type detection device according to 1. 5. The first electrode and the second electrode are arranged on both sides in a width direction or a vertical direction of a door of an elevator or the like,
The capacitance detection device according to claim 1, wherein the detection circuit is configured to be able to detect the presence of a person in front of the door. 6. The apparatus according to claim 1, wherein the detection circuit is configured to be capable of detecting an amount of an object that has entered between the first electrode and the second electrode. Capacitive detection device. 7. A first electrode and a second electrode are arranged on both side walls of a toilet seat of a toilet, and the detection circuit detects whether or not a person is sitting on the toilet seat. The capacitance detection device according to claim 1. 8. The first electrode and the second electrode are arranged on both sides of a passage in a building, and the detection circuit is configured such that a person enters between the first electrode and the second electrode. 2. The capacitance-type detection device according to claim 1, wherein the control unit detects that the operation has been performed and turns on or off the illumination. 9. A self-diagnosis device for performing self-diagnosis of the capacitance type detection device according to claim 1, wherein a first electrode and a first electrode are provided. A capacitance sensor comprising a second electrode arranged opposite to the first electrode; a simulation signal supply unit for supplying a simulation signal for operating the capacitance sensor for performing a self-diagnosis; and a preset width. A comparison signal output unit that outputs a comparison signal of: a comparison determination unit that compares a width of the sensor output signal output from the sensor by the simulation signal with a width of the comparison signal; and a result of the comparison, the sensor An error signal output unit that outputs an error signal when the width of the output signal is shorter than the width of the comparison signal.