JP2009250857A - Capacitance sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a simple cord-type capacitance sensor which exhibits a function as a capacitance-type proximity sensor at a high level, functions also as a touch sensor, and is so flexible that it can be easily attached in conformity to various bent shapes. <P>SOLUTION: The sensor 1 includes: detection electrodes A and B that detect a change in capacitance; and a shield electrode S, having a substantially U-shaped cross-section orthogonal to a long side of the sensor 1, which restricts a detection range of capacitance. The detection electrodes A and B and the shield electrode S are disposed along the long side, the detection electrodes A and B being disposed in positions near and close to an opening made in the shield electrode S, respectively. Each electrode is made of a conducting flexible body, the electrodes being kept away from one another in a natural state. When the sensor 1 is pressed from a direction of detection by making contact with an object, the detection electrodes A and B and/or the detection electrodes A and B and the shield electrode S come in contact and conductive with each other, and the electrodes become coupled together by nonconducting flexible bodies 2 and 3 so that the contact with the object can be detected. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sensor for detecting the pinching of an object in an opening / closing body such as a door.

  In a control system for an opening / closing body such as a door, in order to prevent a human body or the like from being caught, at the time of an automatic closing operation, the occurrence of such a pinching or the possibility of the occurrence is detected and at least the opening / closing body is automatically closed. A pinching prevention function for stopping or further reversing is provided.

  Conventionally, there are indirect detection and direct detection as a method of the detection device that performs pinching detection for preventing such pinching. Indirect detection is to indirectly detect pinching based on operation information (rotation position, rotation speed, etc.) of the drive motor of the opening / closing body and drive current, and direct detection is either close to the opening / closing end of the opening / closing body or A sensor that detects an object to be touched (such as a human body) is used. Among these, indirect detection has the disadvantage that it is relatively difficult to detect pinching quickly and reliably with a load as low as possible. On the other hand, direct detection has the advantage of high reliability because it directly detects the object. However, since this type of conventional sensor uses a pressure-sensitive switch, it can detect pinching with a load as low as possible. I couldn't. This is because the pressure-sensitive switch is a cable-shaped switch using, for example, a conductive resin, and operates when an internal conductor is brought into contact with the object due to deformation due to the pressure of the object. For this reason, the pressure sensitive switch is activated only when the object comes into contact with a certain pressure, and at that time, the pinching prevention function is finally activated.

  By the way, in general, sensors that detect the approach of an object in a non-contact manner include an optical type, a radio wave type, and a capacitance type. Of these, the optical type is difficult to arrange the detection area along the curved opening / closing end of an opening / closing body such as a vehicle door (that is, a large number of sensors are arranged to use highly linear light). (There is a dead zone when the number of sensors is small), and the radio wave type is difficult to limit the directivity to the direction approaching the open / close end, and may cause malfunction. There is a problem that is high. On the other hand, the capacitance type is promising as a cord type because it can be attached relatively easily along a curved opening / closing end, has no dead band, and directivity can be easily controlled.

Therefore, the inventors have studied to apply a capacitance sensor basically as a pinch detection device in a power slide door of a vehicle.
Patent Document 1 describes a door opening / closing detection device that detects an opening / closing state (including pinching) of a train door using a capacitance sensor. Patent Document 2 discloses a technique that uses a capacitance sensor to detect a human being caught in a shutter. Patent Document 3 discloses an automatic door safety device that performs pinching detection using a capacitance sensor. Patent Document 4 discloses a capacitance sensor that can be applied to a vehicle door.

Japanese Patent Laid-Open No. 10-96368 JP 2001-264448 A JP 2001-32627 A WO2004 / 059343

By the way, if the electrostatic capacitance sensor described above is applied to an opening / closing body such as a sliding door of a vehicle to detect pinching, a peripheral member of the opening / closing body (for example, a vehicle B-pillar or Capacitance sensor reacts to the front door, etc.), and the output of the capacitance sensor (hereinafter referred to as sensor output) changes. Actually, the human body is not pinched, but pinching occurs. There was a problem of false detection.
Here, the sliding door is a sliding door provided on the side of the vehicle or the like. In the case of a four-wheeled vehicle, it is generally provided as a rear seat door (rear door).

  In the above-mentioned patent document 3, an allowable value (threshold for detection determination) is set based on, for example, a sensor output (that is, learning data) measured when the automatic door is operated in the opening direction. A technique for determining pinching by comparing the sensor output with the allowable value when the door is in the closing direction. Further, the allowable value is gradually changed based on the learning data in the vicinity of the fully closed position of the door. Technology is disclosed. According to this technique, in principle, the influence of the peripheral member can be canceled by the change in the allowable value, and the possibility of the aforementioned erroneous detection occurring near the fully closed position of the opening / closing body can be reduced.

  However, in the configuration of Patent Document 3, since the threshold value for detection determination is changed according to the learning result in consideration of the influence of the peripheral members, two values to be compared in the detection determination (that is, the sensor output and the allowable value). Value) greatly changes depending on the operating position of the opening / closing body, and the level changes greatly with respect to the operation of the opening / closing body. For this reason, for example, when the sensor output changes as a whole due to noise or temperature drift due to the influence of water droplets or the like, saturation of a signal (for example, the sensor output or a voltage value corresponding to the allowable value) occurs in the circuit that performs detection determination Therefore, there is a possibility that the detection determination is not accurately performed, or the performance (allowable amount against the level change) of the circuit needs to be improved. In particular, when the sensor output is amplified before the detection determination in order to improve the detection sensitivity, the allowable value must also have a larger level change corresponding to the change in the sensor output. Problems due to increase are likely to occur. In addition, since the threshold for detection determination varies greatly depending on the operating position of the opening / closing body, there is a disadvantage that it is difficult to set the detection sensitivity constant over the entire operating range of the opening / closing body.

  In addition, according to recent research by the inventors, the correction based on the above learning data does not function well due to fluctuations in the position of the door based on mechanical backlash and fluctuations in the situation such as the open / closed state of the front door. However, it turned out that there is a risk of increasing the possibility of false detection. This is because when the vehicle tilt direction or tilt angle changes, even if the door position detection value is the same, the door position fluctuates due to mechanical backlash by the amount of mechanical play, so the door position during learning and the actual door position are subtle. Different. Further, when the open / close state of the front door changes with respect to the learning time, the influence of peripheral members on the sensor output in the vicinity of the fully closed position naturally changes. If there is such a position variation or a change in the peripheral member, the threshold value for detection determination (corrected by learning) will deviate from the appropriate value according to the difference, especially in the vicinity of the fully closed position. Therefore, it has been found that there is a possibility that a misdetection in which the detection state is entered even though there is no detection target, or on the contrary, a malfunction that does not occur in the detection state even though the detection target exists.

In addition, although it is said that the electrostatic capacity sensor is easy to be arranged along a car door end that is curved in a cord shape, in a structure in which any electrode is formed of a rigid body, individual application conditions ( Depending on the shape of the door end to be attached, etc., there is a problem that parts having different curved shapes must be manufactured in advance, and parts cannot be shared.
Further, since the capacitance sensor does not react unless it is a dielectric, it cannot detect a low dielectric such as plastic, and for example, it cannot prevent a plastic item to be carried into the vehicle from being caught in the slide door. There are also disadvantages.
In addition, in order to compensate for the disadvantages of the capacitance sensor as described above (the disadvantage that a low dielectric material cannot be detected and the malfunction caused by a surrounding dielectric material), for example, a conventionally used pressure sensitive switch is separately provided, It can be considered to be used in combination with a capacitance sensor. However, this configuration is extremely impractical because of increased costs and installation space.

Further, there is a problem that the capacitance sensor becomes undetectable due to disconnection of the detection electrode. In particular, a cord-type capacitance sensor arranged along a curved door end or the like may cause a long detection electrode to break due to bending stress or the like at some point in the longitudinal direction. The sensor cannot be detected at the tip side of the part where it is made.
In addition, as a sensor for safety devices such as prevention of pinching of the opening / closing body, the above-mentioned problems (problems that cannot be detected if the object is a low dielectric material or problems that become undetectable due to disconnection) are serious. It is necessary to solve it eagerly.

  Accordingly, the present invention provides a simple code-type capacitive sensor that exhibits the original function as a capacitive proximity sensor (non-contact sensor) to a high degree and also functions as a touch sensor that detects contact of an object. In addition, an object of the present invention is to provide a capacitance sensor that is flexible as a whole and can be easily attached along various curved shapes. It is another object of the present invention to provide the above-described capacitance sensor that is unlikely to generate an undetectable state due to disconnection or that has a disconnection detection function.

The capacitance sensor of the present application is a code-type sensor that detects a change in capacitance,
A plurality of detection electrodes for detecting a change in capacitance and a substantially U-shaped cross section orthogonal to the longitudinal direction of the sensor in order to limit the detection range of the capacitance, and an opening in the detection direction And a shield electrode facing the sensor, along the longitudinal direction of the sensor,
The detection electrode is disposed at a position close to the opening in the shield electrode and a position far from the opening in the shield electrode,
The detection electrode and the shield electrode are formed of a conductive flexible body,
When the detection electrodes are kept apart from each other and the detection electrodes and the shield electrodes are separated from each other in a natural state, and the sensor is pushed from the detection direction by contact with an object, the detection electrodes or The detection electrode and the shield electrode are integrally connected by a non-conductive flexible body so that the detection electrode and the shield electrode are in contact with each other and the contact of the object can be detected. And

Here, the “flexible body” is a flexible material made of resin or rubber, for example.
The “detection electrode” includes a main electrode (detection electrode A) disposed at a position close to the opening in the shield electrode, a position far from the opening in the shield electrode, and the main electrode and the shield electrode. There may be a mode in which two types are provided, that is, a reference electrode (detection electrode A) arranged at a position between the two.
Further, “substantially U-shaped” means a shape having an opening on one side, and is not limited to the U-shape itself, and includes, for example, a U-shape, and is partially curved or bent. It may be a constricted shape. That is, the shield electrode only needs to have a hollow shape having a cross-sectional shape having an opening in the detection direction. For example, the shield electrode may be partially curved or bent or partially constricted. For example, the shape of the corners on both sides of the bottom of the shield electrode may be rounded or pointed. For example, as shown in FIG. 5 described later, a shield electrode having a circular cross-sectional outer shape may be used.

According to the capacitance sensor of the present application, it is possible to detect a difference sensitive capacitance change (dielectric approach) with a plurality of detection electrodes, and quickly detect a dielectric such as a human body without contact. it can. Further, since the shield electrode is provided, only the dielectric close to the detection direction (opening side of the shield electrode) is detected, and the dielectric close to the side is not erroneously detected.
In addition, when pressed from the detection direction by contact of an object, the detection electrodes can be detected by contacting each other or / and the detection electrode and the shield electrode. For this reason, it is a code type capacitive sensor having a simple configuration substantially equivalent to the capacitive sensor proposed in WO 2004/059343 (that functions only as a proximity sensor), but as a touch sensor that detects contact of an object. Also works.
Further, since the basic principle as a capacitance sensor (proximity sensor) is exactly the same as that proposed in WO2004 / 059343, as described in the specification of the application, a spatially open area is used. Is a detection range, and proximity detection with few malfunctions can be performed by avoiding the influence of surrounding objects (that is, the original function as a proximity sensor can be exhibited to a high degree).
In addition, since the entire capacitance sensor (that is, the sensor main body) including the detection electrode is integrally formed of a flexible body, it has flexibility as a whole. For this reason, it is not always necessary to pre-shape it into a curved shape according to the shape of the attachment location, and it can be flexibly adapted to the attachment location of various shapes at the assembly site. Yes, parts can be shared and productivity of products (for example, vehicles) to which this sensor is attached can be improved.

The capacitance sensor of the present application naturally requires a detection circuit, but this detection circuit has, for example, the following configuration when there are two types of detection electrodes: detection electrode A and detection electrode B described above. do it.
That is, the capacitance detection circuit A that converts the stray capacitance formed by the detection electrode A using the voltage Vr as a reference voltage into a voltage by the switched capacitor operation, and the stray capacitance formed by the detection electrode B using the voltage Vr as the reference voltage is the switched capacitor. Capacitance detection circuit B that converts the voltage into voltage by operation, voltage adjustment circuit that adjusts the output voltages of the capacitance detection circuits A and B in the non-detection state to be equal, and capacitance detection circuits A and B using voltage Vr as a reference voltage A differential circuit that outputs a voltage corresponding to the output difference of the output signal; a detector circuit that samples the output of the differential circuit at each detection electrode energization timing using the voltage Vr as a reference voltage; and a smoothing circuit that smoothes the output of the detector circuit And a detection circuit using a signal corresponding to the output of the smoothing circuit as a sensor output.
Here, the “floating capacitance” is a capacitance (grounding capacitance) configured by a vehicle body, a human body to be detected, and the like and a detection electrode. The “voltage Vr” is a voltage value greater than zero V.

According to the detection circuit, in the non-detection state (the initial state in which no object approaches or contacts the detection surface), the output voltage of each of the capacitance detection circuits A and B is equal due to the action of the voltage adjustment circuit. (Output of the smoothing circuit) is a value corresponding to the reference voltage Vr. When the object (dielectric material) approaches the detection surface (the side where the shield electrode is opened), the detection electrodes A and B have a distance difference with respect to the detection surface. A difference occurs in the voltage, and as a result, the sensor output changes in one direction from a value corresponding to the reference voltage Vr (for example, increases if the output of the capacitance detection circuit A is a non-inverting input of the difference circuit).
Further, when an object (dielectric or non-dielectric) comes into contact with the detection surface and the detection electrodes A and B come into contact with each other and become conductive, the output voltage of the capacitance detection circuits A and B is caused by the presence of the voltage adjustment circuit. It changes in the reverse direction, and the sensor output changes in the other direction than the value corresponding to the reference voltage Vr (for example, if the output of the capacitance detection circuit A is a non-inverting input of the difference circuit, it decreases to almost zero) ).

In addition, when an object (dielectric or non-dielectric) comes into contact with the detection surface and the detection electrode A and the shield electrode come into contact with each other and become conductive, the discharge of charge from the detection electrode A increases and the sensor output becomes the reference. It changes in one direction from a value corresponding to the voltage Vr (for example, if the output of the capacitance detection circuit A is a non-inverting input of the difference circuit, it increases to a maximum voltage).
In addition, when an object (dielectric or non-dielectric) comes into contact with the detection surface and the detection electrode B and the shield electrode come into contact with each other and become conductive, the discharge of charge from the detection electrode B increases and the sensor output becomes the reference. It changes in the other direction than the value corresponding to the voltage Vr (for example, if the output of the capacitance detection circuit A is a non-inverting input of the difference circuit, it decreases and becomes almost zero).
When both the detection electrodes A and B are brought into contact with the shield electrode and made conductive, the detection electrodes A and B are similar to the case where the detection electrodes A and B are brought into contact with each other and made conductive, and the sensor output is a value corresponding to the reference voltage Vr. (For example, if the output of the capacitance detection circuit A is a non-inverting input of the difference circuit, it decreases and becomes almost zero).
Therefore, according to the detection circuit, if the change in the sensor output described above is compared with a threshold value that is appropriately set above and below the value corresponding to the reference voltage Vr, the approach of the object (dielectric) and the object ( Dielectric or non-dielectric) contact can be determined by the same detection circuit. Therefore, according to this detection circuit, it is possible to realize an excellent feature that a single detection circuit can continuously detect the approach and contact of an object in real time without switching between the detection circuit and the signal processing.

Next, according to a preferred aspect of the present application, the main electrode and the comparison electrode are first brought into contact with each other by detecting that the sensor is pushed from the detection direction and deformed by contact with the object. By being deformed, the main electrode, the comparison electrode, and the shield electrode come into contact with each other, and the contact of the object can be detected.
In this aspect, since the contact of the object can be detected in two stages, the detection reliability is improved against the disconnection. For example, even if the main electrode is disconnected, the contact of the object can be detected by the contact of the comparison electrode and the shield electrode. Even if the comparison electrode is disconnected, the contact of the object is detected by the contact of the main electrode and the shield electrode. This is because even if the shield electrode is disconnected, the contact of the object can be detected by the contact between the main electrode and the comparison electrode.
In addition, a stage in which contact of an object is first detected (state in which the main electrode and the comparison electrode are in contact with each other), and a stage in which contact with an object is subsequently detected (in a state in which each electrode is in contact with each other) Thus, when the sensor output is different (for example, when the sensor output changes in the opposite direction), it is possible to determine the degree of contact (indentation stroke) in two stages.

  Next, another preferable aspect of the present application is that the main electrode and the shield electrode are first brought into contact with each other and the contact of the object can be detected by the sensor being pushed from the detection direction and deformed by the contact of the object. Further, by further deformation, the main electrode, the comparison electrode, and the shield electrode are in contact with each other, and the contact of the object can be detected. Even in this aspect, since the contact of the object can be detected in two stages, the detection reliability is improved with respect to the disconnection, and in some cases, the indentation stroke can be determined.

  Next, another preferred aspect of the present application is that the sensor is pushed from the detection direction and deformed by contact with the object, so that the comparison electrode and the shield electrode first contact each other and the contact of the object can be detected. Further, by further deformation, the main electrode, the comparison electrode, and the shield electrode are in contact with each other, and the contact of the object can be detected. Even in this aspect, since the contact of the object can be detected in two stages, the detection reliability is improved with respect to the disconnection, and in some cases, the indentation stroke can be determined.

Next, another preferable aspect of the present application is that at least the comparison is performed by connecting a capacitor having a capacitance larger than the capacitance between the main electrode and the comparison electrode between the main electrode and the tip of the comparison electrode. In this configuration, the disconnection of the electrode can be detected. According to this aspect, the stray capacitance between the reference electrode and the ground decreases due to the disconnection of the reference electrode (that is, the discharge of electric charges decreases), so that the sensor output as the capacitance sensor changes in one direction ( For example, in the detection circuit described above, if the output of the capacitance detection circuit A is a non-inverting input of the difference circuit, the output of the capacitance detection circuit B decreases due to the disconnection of the comparison electrode, so that the sensor output increases), and this The changed state is maintained. Therefore, if such a change in sensor output continues, it can be determined that the object is not approaching but the reference electrode is disconnected.
When the main electrode is disconnected, the sensor output as the capacitance sensor changes even if the above-described capacitor is not connected. Therefore, it is possible to detect the disconnection of the main electrode even without the above-described capacitor. For this reason, the above aspect is particularly significant in that it is possible to detect disconnection of the comparison electrode, which is normally undetectable.

Next, another preferable aspect of the present application is that a conducting wire made of a material having a smaller electric resistance than the conductive flexible body is provided inside or on the outer peripheral surface of the detection electrode and / or the shield electrode. Arranged along the longitudinal direction,
In this configuration, the installation position of the conducting wire is set near the neutral plane of the sensor with respect to bending in a plane orthogonal to the detection direction.
The “neutral surface” means a surface where the bending stress is zero.
Moreover, when the conducting wire as described above is provided, there are the following advantages. First, the resistance distribution of the detection electrode can be reduced. In general, conductive materials such as conductive rubber have a higher resistance value than that of metal conductors, etc., so that when modulated electric drive is applied, the waveform becomes distorted due to the effect of the resistance value. There will be a difference. This adverse effect is particularly significant when the length is long. However, providing a conducting wire as described above has the advantage of reducing such an adverse effect by reducing the overall resistance value. Next, secondly, there is an advantage that connection with a cable for power feeding or signal extraction (connection with the detection circuit side) can be easily performed through the conductive wire.
Moreover, the following effect is acquired because the said conducting wire is installed in the neutral surface vicinity. That is, even if the conducting wire is made of a material that does not have sufficient stretchability, the stress applied to the conducting wire by the bending is zero or slight, so the characteristic of the sensor that the bending is easy to perform without stress. Therefore, it is possible to maintain the ease of attaching the present sensor by curving it according to the shape of the door end or the like.

Next, another preferable aspect of the present invention is a configuration characterized in that the surface is subjected to water-repellent processing and / or oil-repellent processing.
In this case, there is an effect of reducing the possibility of malfunction due to moisture or oil. According to the researches of the inventors, for example, when water droplets or the like continuously adhere across the detection surface of a capacitance sensor (sensor body portion excluding the detection circuit), the object (dielectric material) approaches. In spite of the absence, there is a phenomenon that the sensor output changes and it is erroneously determined that the object is approaching. According to this aspect, since continuous adhesion of water droplets or the like is prevented, such a malfunction is less likely to occur.

  In addition, the electrostatic capacitance sensor of this application can be applied to the pinch prevention device of an opening / closing body. That is, it is determined that the object has approached the detection surface based on the capacitance sensor of the present application and, for example, the output of the capacitance sensor changes in one direction from the non-detection state, and the capacitance sensor For example, a determination circuit that determines that an object has contacted the detection surface based on a change in the other direction (or larger in one direction) than in the non-detection state, , A sliding door of a vehicle) is detected by the electrostatic capacity sensor to detect an object that approaches or contacts a position range that may be sandwiched between the opening and closing body, and based on the determination result of the determination circuit Thus, the device configuration may be such that the sandwiching of the opening / closing body is detected.

As described above, when the electrostatic capacitance sensor of the present application is applied to the sandwiching prevention device for the opening and closing body, the following effects can be obtained.
In other words, the capacitance sensor of the present application that can also function as a touch sensor is used, and a determination circuit for determining whether an object is approaching or touching is provided, and pinching of the opening / closing body is detected based on the determination result. For this reason, in a state that can be satisfactorily detected as a capacitive proximity sensor (for example, a state in which the opening / closing body is located outside the position range that is difficult to detect near full closure), for example, the determination circuit determines that the object has approached If it is determined that pinching has occurred and the pinching prevention operation is executed, the pinching prevention operation can be executed earlier with a lower load (possibly with no load) than with a pressure-sensitive switch. In a state where it is difficult to detect well as a capacitive proximity sensor (for example, a state where an opening / closing body is located in a position range where detection is difficult near full closure), when the determination circuit determines that an object has contacted, If it is determined that pinching has occurred and the pinching prevention operation is executed, even if it is difficult to detect as a capacitive proximity sensor, the pinching prevention operation can be accurately realized without malfunction. Even in a state where it can be satisfactorily detected as a capacitive proximity sensor, if the determination circuit determines that an object has touched, if it is determined that pinching has occurred and the pinch prevention operation must be executed, Even if it is a low-dielectric material such as plastic, it is possible to detect the pinching and reliably perform the pinching prevention operation.
That is, according to the open / close body pinching detection device, the pinching detection device has both the advantages of the touch sensor method and the capacitive proximity sensor method, and the configuration of the device is the same as that of the capacitive proximity sensor method. An apparatus with a simple configuration of the degree can be realized. Furthermore, it is possible to secure high attachment of the sensor to a curved door end or the like, and it is possible to improve the reliability of pinching detection with respect to disconnection of the sensor.

  According to the present invention, a simple code-type capacitance that exhibits the original function as a capacitance-type proximity sensor (non-contact sensor) at a high level and also functions as a touch sensor that detects contact of an object. It is possible to obtain a capacitive sensor that is a sensor and that is flexible as a whole and can be easily attached along various curved shapes.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
First, the first embodiment will be described.
FIG. 1A is a diagram schematically showing the internal configuration of the sensor main body 1 of the capacitance sensor, and FIG. 1B is a first operation state of the sensor main body 1 (a state in which the sensor main body 1 is crushed by an object). FIG. 1C is a diagram illustrating a second operating state of the sensor body 1 (a state in which the sensor body 1 is further crushed by an object). FIG. 4A is a perspective view showing the entire sensor body 1, and FIG. 4B is a horizontal sectional view showing the sensor body 1 and its peripheral configuration. FIG. 5 is a diagram illustrating a specific example (an example of an actual configuration) of the internal configuration of the sensor body 1. FIG. 7 is a block diagram showing an outline of a pinch detection device (including a detection circuit and the like) including the capacitance sensor of this example. 8 and 9 are circuit diagrams showing specific examples of the detection circuit 20 of the capacitance sensor. FIG. 10 is a diagram illustrating the proximity detection area and the touch detection area. FIG. 11 is a timing chart for explaining the operation of the detection circuit 20, and FIG. 12 is a diagram showing an example of data for explaining the operation of the detection circuit 20.

As shown in FIG. 1 (a), the sensor body 1 is formed of a conductive flexible body (for example, a material based on natural rubber, synthetic rubber, or elastomer and having appropriate flexibility and conductivity). A detection electrode A, B formed on the inner side of the shield electrode S, a shield electrode S having a substantially U-shaped cross-section with an opening on the detection surface side, and a conductive flexible body; The low dielectric constant insulating material 2 disposed on the detection surface side, the detection electrode B, and the shield electrode S are connected (to the shield electrode S) so as to connect the upper surface of the detection electrode A (the surface on the detection surface side). Low dielectric constant disposed so as to be interposed between the inner bottom surface of the shield electrode S and the lower end of the detection electrode B (the end opposite to the detection surface) so as to support the detection electrode B). It consists of an insulating material 3.
Inside each of the detection electrodes A and B and the shield electrode S of the sensor main body 1, conductive wires 4, 5, and 6 made of a material (for example, copper wire) having a smaller electric resistance than the conductive flexible body are provided. Each is arranged. In addition, the installation positions of these conducting wires 4, 5, and 6 are set near the neutral surface (surface with zero bending stress) of the sensor with respect to bending in a plane orthogonal to the detection direction (vertical direction in FIG. 1). Yes.
Further, in the middle of the left and right sides of the shield electrode S (position between the detection electrodes A and B), a protruding portion 7 that protrudes inward (toward the detection electrodes A and B) is provided. Yes.

The low dielectric constant insulating material 2 and the low dielectric constant insulating material 3 are based on a non-conductive flexible body (for example, natural rubber, synthetic rubber, or elastomer, have moderate flexibility, and have conductivity. The dielectric constant is low so that the detection operation as a capacitance sensor is not adversely affected. In the specific example of FIG. 5, the low dielectric constant insulating material 2 is provided so as to cover the entire sensor body 1 in the cross section of the sensor body 1.
The sensor body 1 is manufactured as a single body by, for example, integrally molding each flexible body (shield electrode S, detection electrodes A and B, low dielectric constant insulating material 2 and low dielectric constant insulating material 3). Is done.
The sensor body 1 is of a cord type as shown in FIG. 4 (a), and has a uniform cross section in which each flexible body and each conductor are arranged in the longitudinal direction. However, the sensor body 1 does not necessarily have to be long. For example, the sensor body 1 may have a shorter length in the longitudinal direction (direction perpendicular to the cross section) than the cross sectional dimension. Nor.
The sensor body 1 having such a configuration can be made sufficiently small, has sufficient bending workability and flexibility, and can be easily curved in the longitudinal direction. It is sufficiently possible to arrange it compactly along the shape of the ten open / close ends. Further, due to the shielding action of the shield electrode S, only the detection surface side (that is, the side of the position range that faces the end portion of the slide door 10 and is likely to be sandwiched by the slide door 10) is made highly sensitive, and the other surface Can be basically insensitive.

Here, the detection electrodes A and B are arranged at positions relatively close to and far from the detection surface, respectively. In this case, the detection electrode A corresponds to the main electrode and is disposed at a position near the opening in the shield electrode S. On the other hand, the detection electrode B corresponds to a comparison electrode and is a position far from the opening in the shield electrode S, and a position between the main electrode (detection electrode A) and the shield electrode S (position on the back side of the detection electrode A). ).
Further, the detection electrodes A and B are arranged so as to have a predetermined distance difference in a direction facing the detection surface in a natural state where no external force is applied to the sensor body 1 and do not contact the shield electrode S. (In other words, the low dielectric constant insulating material 2 and the low dielectric constant insulating material 3 connect the electrodes and support each other so that they are arranged in such a manner). When the detection surface of the sensor body 1 is pressed by contact with an object, as shown by arrows in FIG. 1B, the detection electrode A on the detection surface side and the portion where the low dielectric constant insulating material 2 is pressed (longitudinal) (Part of the direction) is deformed so as to move to the back side, the detection electrode A comes into contact with the detection electrode B on the back side, and only the detection electrodes A and B are in a first operation state in which they are electrically connected to each other. Has been. In addition, even if the force which an object pushes is added diagonally within a certain range (refer FIG.2 (c)), it will be in a 1st operation state similarly. Next, when the detection surface of the sensor body 1 is further pushed by contact with an object, the detection electrode A on the detection surface side and the pressed portion of the low dielectric constant insulating material 2 are pressed as shown by arrows in FIG. While (a part of the longitudinal direction) is further deformed so as to move further to the back side, the projecting portion 7 of the shield electrode S is deformed so as to advance inward, so that the shield electrode S becomes the detection electrode A and the detection electrode B. And the detection electrodes A and B and the shield electrode S are in a second operating state in which they are electrically connected to each other.

As shown in FIG. 4B, the sensor main body 1 is attached to an open / close end portion of a slide door 10 (rear door) in a vehicle via a bracket 11. FIG. 4B shows a state in which the slide door 10 is closed. In this closed state, the slide door 10 is located on the B-pillar 12 (between the front door 13 and the slide door 10, on the vehicle body side). It is joined to the front door 13 with a slight gap so as to sandwich the column). Further, a hem portion 14 that protrudes toward the front door 13 is formed at the open / close end portion of the slide door 10, and the tip of the hem portion 14 extends inside the front door 13 in the closed state. And the junction part of the front door 13 is closed with respect to the vehicle exterior.
The sensor main body 1 is disposed on the inner side (vehicle inner side) of the hem portion 14 and protrudes toward the front door 13 so that the detection surface thereof is further protruded toward the front door 13 than the hem portion 14. It attaches to the front-end | tip of the bracket 11 to perform by adhesion | attachment etc., for example.
In practice, as shown in the specific example of FIG. 5, a protective cover 8 (made of flexible non-conductive resin or rubber) is attached around the sensor body 1.

Further, for example, silicon tape is attached to the surface of the sensor body 1 and the peripheral portion of the sensor body 1 (the bracket 11 and the hem part 14 or the part on the side of the sensor body 1) to provide a water-repellent finish. Has been. In addition, you may give water-repellent coating and / or oil-repellent processing, such as oil-repellent coating.
If such a process is applied, it is difficult for water and oil droplets to adhere to this surface, and even if they adhere, they are likely to be dispersed and flowed down due to water or oil repellent action, and large water droplets or the like that cause malfunctions or continuous Therefore, the possibility of malfunction caused by the water droplets described above is greatly reduced.

Next, a circuit unit that is connected to the sensor body 1 and drives the sensor body 1 and performs signal processing will be described.
As shown in FIG. 7 or FIGS. 8 to 9, this circuit unit includes a pulse drive circuit 21 A for the detection electrode A, a pulse drive circuit 21 B for the detection electrode B, a charge integration circuit 22 A for the detection electrode A, and a charge integration for the detection electrode B. A circuit 22B, a difference circuit 23, a detection circuit 24, a smoothing circuit 25, a voltage adjustment circuit 26A, a voltage adjustment circuit 26B, a subtraction circuit 27, an amplification circuit 28, and a determination circuit 29 are provided.
Here, the pulse drive circuit 21A and the charge integration circuit 22A constitute a capacitance detection circuit 30A (capacitance detection circuit A) that converts the stray capacitance formed by the detection electrode A into a voltage by a switched capacitor operation using the voltage Vr as a reference voltage. is doing. The pulse drive circuit 21B and the charge integration circuit 22B constitute a capacitance detection circuit 30B (capacitance detection circuit B) that converts the stray capacitance formed by the detection electrode B into a voltage by a switched capacitor operation using the voltage Vr as a reference voltage. ing. Further, the subtraction circuit 27 and the amplification circuit 28 constitute a subtraction amplification circuit 31.
In this case, up to the amplifier circuit 28 constitutes the sensor detection circuit 20, and the output TP7 of the amplifier circuit 28 is the final sensor output. The voltage Vr used as the reference voltage is a constant voltage (for example, 2.5 V) generated from the power supply voltage (for example, 5 V) by a voltage dividing circuit (not shown).

  As shown in FIG. 8, the pulse drive circuit 21A includes a switch SW-A1 that is driven by a drive circuit (not shown) and switches the connection of the detection electrode A at high speed. The switch SW-A1 has a common terminal, a ground terminal, an Open terminal, and a DPA terminal (not shown), the common terminal is connected to the detection electrode A, the ground terminal is connected to the vehicle ground, and the DPA terminal is described later. It is connected to the inverting input of the OP amplifier 35A. Further, as shown in the uppermost stage of FIG. 11, the switch SW-A1 includes a GND state in which the common terminal is electrically connected to the ground terminal, an Open state in which the common terminal is electrically connected to the Open terminal, and a DPA in which the common terminal is electrically connected to the DPA terminal. Switching to the connected state periodically at high speed. In FIG. 8, a capacitance indicated by a symbol Ca indicates a stray capacitance formed by the detection electrode A.

  The pulse drive circuit 21B includes a switch SW-B1 similar to the switch SW-A1 of the pulse drive circuit 21A. The switch SW-B1 has a common terminal connected to the detection electrode B, a ground terminal connected to the vehicle ground, and a DPA terminal connected to an inverting input of an OP amplifier 35B described later. Further, the switch SW-B1 operates in the same manner as the switch SW-A1, as shown in the uppermost stage of FIG. In FIG. 8, the capacitance indicated by the symbol Cb indicates a stray capacitance formed by the detection electrode B.

The charge integration circuit 22A supplies a pulse voltage (voltage Vr) to an OP amplifier (operational amplifier) 35A, a switch SW-A2 and a capacitor Cfa that constitute a feedback circuit of the OP amplifier 35A, and a non-inverting input of the OP amplifier 35A. And a power supply circuit 36A.
Here, the capacitor Cfa is connected between the output TP1 of the OP amplifier 35A and the inverting input. The switch SW-A2 is connected in parallel with the capacitor Cfa and opens / closes between both terminals of the capacitor Cfa (that is, between the output and the inverting input of the OP amplifier 35A). Further, the switch SW-A2 is driven by a drive circuit (not shown) and, as shown in the third stage from the top in FIG. 11, at the timing of the Open state before the switch SW-A1 enters the DPA connection state, the On state Is switched from the Off state to the On state at the timing when the switch SW-A1 is switched from the Open state to the GND state.

Further, the output of the power supply circuit 36A changes periodically as shown in the second stage from the top in FIG. That is, at the timing when the switch SW-A2 switches from the On state to the Off state, the charging voltage (voltage Vr) changes from the ground voltage to the charging voltage Vr at the timing after the switch SW-A1 switches from the DPA connection state to the Open state. To the ground voltage.
Although not shown, a similar pulse voltage (voltage Vr) is also supplied to the shield electrode S.

Similarly to the charge integration circuit 22A, the charge integration circuit 22B includes an OP amplifier 35B, a switch SW-B2 and a capacitor Cfb constituting the feedback circuit, and a power supply circuit 36B that supplies a pulse voltage to the non-inverting input of the OP amplifier 35B. With.
Here, the capacitor Cfb is connected between the output TP2 of the OP amplifier 35B and the inverting input. The switch SW-B2 is connected in parallel with the capacitor Cfb and opens / closes between both terminals of the capacitor Cfb (that is, between the output and the inverting input of the OP amplifier 35B). Further, the switch SW-B2 operates in the same manner as the switch SW-A2, as shown in the third row from the top in FIG. Further, the output of the power supply circuit 36B changes as shown in the second stage from the top in FIG. 11, similarly to the power supply circuit 36A.

As shown in FIG. 8, the difference circuit 23 is composed of a resistor that is omitted from the OP amplifier 37, and outputs TP1 (output of the capacitance detection circuit A) of the OP amplifier 35A and output TP2 (output of the capacitance detection circuit B of the OP amplifier 35B). This is a circuit that calculates and outputs the difference of the output. Since the difference circuit 23 uses the voltage Vr as a reference voltage, when there is no difference between the output TP1 and the output TP2, the output TP3 becomes the reference voltage Vr.
The detection circuit 24 is a synchronous detection circuit that extracts the signal voltage TP4 from the output TP3 of the difference circuit 23 using the voltage Vr as a reference voltage. The detection circuit 24 is composed of SW-3 (a switch that is turned on at each detection electrode energization timing) as shown in the fourth row from the top in FIG.

  As shown in FIG. 8, the smoothing circuit 25 is an integrating circuit composed of a resistor or a capacitor that is omitted from the OP amplifier 38, functions as an LPF (low-pass filter), and uses an unnecessary high-frequency component from the output TP4 of the detection circuit 24. Is a circuit that removes and smoothes.

Further, as shown in FIG. 8, the voltage adjustment circuits 26A and 26B are composed of variable capacitors VCa and VCb respectively connected between the detection electrodes A and B and the ground. The values of these variable capacitors VCa and VCb are set in advance so that the output voltages TP1 and TP2 of the capacitance detection circuits A and B in the non-detection state are equal.
Without the voltage adjustment circuits 26A and 26B, the detection electrode A is disposed near the detection surface and the amount of charge emission is large. Therefore, the output voltage TP1 is more than the output voltage TP2 despite the non-detection state. Will also grow. Therefore, these voltage adjustment circuits 26A and 26B are provided to adjust the outputs TP1 and TP2 to be equal in the non-detection state as VCa <VCb.

  The circuit configuration up to the smoothing circuit 25 described above is basically the same as that proposed in the prior application (WO 2004/059443). The specification of the prior application does not disclose components corresponding to the detection circuit 24, the smoothing circuit 25, and the voltage adjustment circuits 26A and 26B. However, in practice, such a circuit is necessary. This is because it is normal. However, what is disclosed in the prior application is different from the present embodiment in that the reference voltage of the difference circuit or the like is the ground voltage (zero V) and the sensor output in the non-detection state is zero V.

Next, as shown in FIG. 9, the subtraction circuit 27 is composed of a resistor omitted from the OP amplifier 39, subtracts a value corresponding to the voltage Vr from the output TP5 of the smoothing circuit 25, and amplifies (pre- Amplify).
As shown in FIG. 9, the amplifier circuit 28 is composed of a resistor omitted from the OP amplifier 40, subtracts a value corresponding to the offset voltage from the output TP6 of the subtractor circuit 27, and amplifies the final result (final amplification). ) The offset voltage is generated by, for example, an offset voltage adjustment circuit 41 (variable output voltage type) shown in FIG. The offset voltage adjusting circuit 41 may be a simple voltage dividing circuit (with a constant output voltage).
The output of the amplifier circuit 28 (output of the OP amplifier 40) is the sensor output TP7 in this example. The offset voltage is used to adjust the final sensor output TP7 to a predetermined level corresponding to the determination circuit 29. For example, in the non-detection state, when the output of the smoothing circuit TP5 is a voltage Vr (for example, 2.5V), the offset voltage is set so that the sensor output TP7 becomes a predetermined initial value V0 (for example, 1V). .

  In the case of the capacitance sensor including the detection circuit configured as described above, in the non-detection state, the output voltages TP1 and TP2 of the capacitance detection circuits 30A and 30B are equal due to the action of the voltage adjustment circuits 26A and 26B. 11, the sensor output (outputs from TP3 to TP7) has a value corresponding to the reference voltage Vr, and the final sensor output TP7 in this case is an initial value V0 (for example, 1V). When an object (dielectric material) approaches the detection surface, the detection electrodes A and B have a distance difference with respect to the detection surface, so that the output voltage TP1 of the capacitance detection circuit 30A is higher than that of the capacitance detection circuit 30B. As a result, the sensor output TP7 increases and becomes much larger than the initial value V0 corresponding to the reference voltage Vr, as shown in the “proximity detection state” portion of FIG. Also, when an object (dielectric or non-dielectric) comes into contact with the detection surface and the detection electrodes A and B come into contact with each other and become in a first operating state, the output is caused by the presence of the voltage adjustment circuits 26A and 26B. The voltage TP1 becomes smaller than the output voltage TP2, and the sensor output TP7 decreases from the initial value V0 to almost zero V as shown in the “touch detection state” in FIG. Similarly, even if the detection electrodes A and B and the shield electrode S are brought into contact with each other and become in the second operating state, the sensor output TP7 is reduced from the initial value V0 to almost zero V.

The principle that the sensor output TP7 becomes zero V when the detection electrodes A and B come into contact with each other can be explained as follows. That is, when the detection electrodes A and B are brought into conduction, a contact resistance as shown by a dotted line in FIG. 8 is formed as a circuit. In such a circuit, since the variable capacitor VCa of the voltage adjustment circuit 26A is set smaller than the variable capacitor VCb of the voltage adjustment circuit 26B, the output TP1 exhibits HPF (high-pass filter) characteristics. The output TP1 exhibits an LPF (low-pass filter) characteristic on the contrary, and the output voltage TP1 becomes smaller than the output voltage TP2 regardless of the approaching state of the dielectric. For this reason, the output TP3 of the difference circuit 23 at the time of sampling becomes substantially zero V, and the outputs TP5 to TP7 after the smoothing circuit 25 all become substantially zero V.
FIG. 12A is an example of waveform data (the horizontal axis is time) of the output voltages TP1 and TP2 when the detection electrodes A and B are in a conductive state (touch detection state). When the detection electrodes A and B are turned on, the relationship between the output voltages TP1 and TP2 always becomes such a magnitude relationship, and the sensor output TP7 becomes zero V.

For this reason, the capacitive sensor of this example has a simple configuration substantially equivalent to that of the capacitive sensor proposed in WO 2004/059343 (which functions only as a proximity sensor), but detects a touch of an object. It also functions as a sensor. Note that the capacitance sensor of the present application uses the output TP7 of the same detection circuit as a common sensor output for the approach and contact of an object, and the sensor output TP7 is basically in the opposite direction to the approach and contact of the object. Since it changes and detects the approach or contact of an object, it has an excellent feature that it can detect the approach and contact of an object in real time and continuously without switching a detection circuit or signal processing.
FIG. 12B is a data example showing a change in the sensor output TP7 when the dielectric approaches the sensor body 1. When the dielectric approaches the sensor body 1, the sensor output TP7 increases as described above, and the proximity detection state is entered when the proximity detection threshold voltage is exceeded. When the dielectric further moves relative to the detection surface of the sensor body 1 and makes contact with the detection electrodes A and B by contacting the detection surface, the sensor output TP7 decreases instantaneously and becomes substantially zero V, and touch It becomes a detection state. Thus, according to this sensor, the approach and contact of an object (dielectric material) can be detected continuously in real time.
FIG. 12C is a data example showing a change in the sensor output TP7 when a non-dielectric material approaches the sensor body 1. When the non-dielectric material approaches the sensor main body 1, since the capacitance does not change, the sensor output TP7 is maintained at the value V0 corresponding to the reference voltage and does not enter the proximity detection state. However, when the dielectric further moves relative to the detection surface of the sensor body 1 and makes contact with the detection electrodes A and B by contacting the detection surface, the sensor output TP7 decreases instantaneously and becomes substantially zero V, and touch It becomes a detection state. As described above, according to the present sensor, contact of an object (non-dielectric material) can be detected in real time.

In addition, since the basic principle of the capacitance sensor of this example as a capacitance sensor (proximity sensor) is exactly the same as that proposed in WO 2004/059343, it is described in the specification of the application. In addition, a spatially open area is used as a detection range, and proximity detection with few malfunctions can be performed by avoiding the influence of surrounding objects (that is, the original function as a proximity sensor can be exhibited to a high degree).
Further, the capacitance sensor of this example includes a subtraction amplification circuit 31 that subtracts a value corresponding to the voltage Vr from the output of the smoothing circuit 25 and amplifies the subtraction result, and outputs the output of the subtraction amplification circuit 31 as a sensor output. It is said. Therefore, since the sensor output before amplification is obtained by subtracting the value corresponding to the voltage Vr, only the change due to the approach or contact of the object is taken out before amplification, and the change width of the output signal is the minimum necessary. Therefore, the sensor output can be easily handled (signal amplification and offset processing described later in the downstream of the smoothing circuit, or determination processing described later).

In addition, the capacitance sensor of this example has high reliability against disconnection.
First, when the detection electrode A is disconnected (when the disconnection portion is not at the tip side), the discharge of electric charge from the detection electrode A is reduced, and the sensor output TP7 is constantly reduced. Thus, disconnection of the detection electrode A can be detected. Further, in this example, even when the detection electrode A is disconnected and an object comes into contact with the tip side of the disconnection point, the detection electrode B and the shield electrode S are in a conductive state when the second operation state is reached. As a result, the sensor output TP7 becomes substantially zero V, and the contact state of the object is reliably detected. When the detection electrode B and the shield electrode S are brought into contact with each other and become conductive, the discharge of charge from the detection electrode B increases, and the sensor output changes in the other direction than the value corresponding to the reference voltage Vr (in this case, This is because the output of the capacitance detection circuit A is a non-inverting input of the difference circuit, so that the sensor output TP7 decreases and becomes almost zero).
In addition, even when the detection electrode B is disconnected and an object is in contact with the tip side of the disconnection point, the detection electrode A and the shield electrode S are in a conductive state at the time when the second operation state is established. Thereby, the sensor output TP7 becomes the maximum voltage in this case, and the object is reliably detected. This is because when the detection electrode A and the shield electrode are brought into contact with each other and conducted, the discharge of charge from the detection electrode A increases, and the sensor output TP7 changes in one direction from the value corresponding to the reference voltage Vr. (In this case, since the output of the capacitance detection circuit A is the non-inverting input of the difference circuit, it increases to the maximum voltage). However, in the case of this example, when the sensor output TP7 increases, the contact of this object is detected as the approach of the object. Note that, for example, by determining the increase in the sensor output TP7 to the maximum voltage by a control process of the control circuit 50 described later, the contact of the object when the detection electrode B is disconnected is detected as a contact. It is also possible.

Next, the determination circuit 29 will be described.
The determination circuit 29 determines that the object (dielectric material) has approached the detection surface based on the sensor output TP7 changing in an increasing direction from the initial value V0 (for example, 1 V) in the non-detection state, and the sensor output TP7. Is a circuit that determines that an object (dielectric material and non-dielectric material) is in contact with the detection surface based on a change in a decreasing direction from the initial value V0. In this case, the circuit includes comparators 42 and 43. The comparator 42 compares the sensor output TP7 with a proximity detection threshold voltage (for example, 1.2 V or more), and turns on the output (proximity detection output) when the sensor output TP7 increases and exceeds the proximity detection threshold voltage. Circuit. On the other hand, the comparator 43 compares the sensor output TP7 with the touch detection threshold voltage (for example, 0.5V), and turns on the output (touch detection output) when the sensor output TP7 decreases and falls below the touch detection threshold voltage. It is a circuit to do. The touch detection threshold voltage may be a constant value in a range from zero V to less than the initial value V0. However, the proximity detection threshold voltage may be changed with respect to the door position based on learning data, for example, as described in Patent Document 3 described above in consideration of the influence of peripheral members near the fully closed position. . In this case, as shown in FIG. 10, the proximity detection cannot be performed in a saturation region where the proximity detection threshold voltage exceeds the maximum voltage (for example, 5 V which is the power supply voltage).

The determination results (proximity detection output and touch detection output) of the determination circuit 29 described above are used, for example, in the following manner in the control circuit 50 for the electric sliding door. That is, as a capacitive proximity sensor, a proximity detection region in which proximity detection is possible without any problem (for example, a range in which the sensor output does not saturate as shown in FIG. 10 or an error due to the mechanical play described above). In a more limited range in which no detection occurs, when the proximity detection output is turned on, the pinching prevention operation is executed because pinching has occurred (or there is a risk of pinching). Further, as shown in FIG. 10, in the entire range including the proximity detection area, when the touch detection output is turned on, the pinch prevention operation is executed because pinching has occurred (or there is a risk of pinching).
The sensor output TP7 signal (digitized by a D / A converter not shown) is input to a microcomputer including the CPU of the control circuit 50, and the control process of the control circuit 50 (for example, the detection electrode A described above). May be used for detection of disconnection of an object or object contact determination processing when the detection electrode B is disconnected.

With the pinching detection device including the capacitance sensor described above, the following effects can be obtained.
(1) The detection area can be arranged along the curved open / close end of the vehicle door (that is, the dead zone can be eliminated), and the directivity of the shield electrode S only in the direction approaching the open / close end. The possibility of malfunction is low.
(2) In addition, since the entire main body including the detection electrode and the shield electrode is made of a flexible body, the main body has flexibility as a whole. For this reason, it is not always necessary to shape it in advance according to the shape of the attachment location (door end), and it is necessary to flexibly adapt to the attachment location of various shapes at the assembly site. ) Is possible, and it is possible to share parts and improve the productivity of a product (in this case, a vehicle) to which this sensor is attached.
(3) In the proximity detection region, since a dielectric such as a human body that is an object can be detected in a non-contact manner, the risk of pinching or pinching occurrence is determined at an early stage, and pinching prevention operation (with little pinching load) ( The closing operation of the opening / closing body can be stopped, or a predetermined amount of opening operation) can be executed.
(4) Since a differential charge transfer type electrostatic capacity sensor is used, detection with high sensitivity to noise is possible.

(5) In a state where it can be satisfactorily detected as a capacitive proximity sensor (a state where the slide door is located in the proximity detection region described above), for example, when the determination circuit 29 determines that an object has approached (the proximity detection output is If the control circuit 50 determines that pinching has occurred and executes the pinching prevention operation when the control circuit 50 is turned on, the pinching prevention operation can be performed earlier with a lower load than the conventional one using a pressure sensitive switch. For example, when the determination circuit 29 determines that an object has touched the entire range (when the touch detection output is turned on), the control circuit 50 always determines that pinching has occurred and executes the pinching prevention operation. By doing so, even if the capacitive proximity sensor is in a state where it is difficult to detect well (a state where the sliding door is located outside the proximity detection area described above), the touch detection can accurately prevent pinching without malfunction. realizable. In addition, by the touch detection, the object can be detected even if it is a low dielectric material such as plastic, and the pinching prevention operation can be reliably executed. In other words, according to the open / closed body pinching detection device using the sensor of this example, the pinching detection device has both the advantages of the touch sensor method and the capacitive proximity sensor method, and the device configuration has a capacitance. A device having a simple configuration similar to that of the type proximity sensor method can be realized.

(6) In addition, this sensor is pushed and deformed by the contact of the object from the detection direction. First, the detection electrode A and the detection electrode B come into contact with each other so that the contact of the object can be detected. The detection electrode A, the detection electrode B, and the shield electrode S are in contact with each other so that the contact of the object can be detected. Thereby, since the contact of an object can be detected in two stages, the detection reliability is improved against disconnection. As described above, for example, even if the detection electrode A is disconnected, the contact of the object can be detected by the contact between the detection electrode B and the shield electrode S. Even if the detection electrode B is disconnected, the detection electrode A This is because the contact of the object can be detected by the contact of the shield electrode S, and even if the shield electrode S is disconnected, the contact of the object can be detected by the contact of the detection electrode A and the detection electrode B.

(7) Moreover, in this example, the conducting wires 4 to 6 made of a material having a smaller electric resistance than the flexible body constituting each electrode are provided in the detection electrodes A and B and the shield electrode S in the longitudinal direction of the sensor. The installation position of these conductors was set near the neutral plane of the sensor against bending in a plane orthogonal to the detection direction. For this reason, first, the resistance distribution of each electrode can be reduced. In general, conductive materials such as conductive rubber have a higher resistance value than that of metal conductors, etc., so that when modulated electric drive is applied, the waveform becomes distorted due to the effect of the resistance value. There will be a difference. This adverse effect is particularly significant when the length is long. However, providing a conducting wire as described above has the advantage of reducing such an adverse effect by reducing the overall resistance value. Next, secondly, there is an advantage that connection with a cable for power feeding or signal extraction (connection with the detection circuit side) can be easily performed through the conductive wire.
Moreover, the following effect is acquired because the said conducting wire is installed in the neutral surface vicinity. That is, even if the conducting wire is made of a material that does not have sufficient stretchability, the stress applied to the conducting wire by the bending is zero or slight, so the characteristic of the sensor that the bending is easy to perform without stress. Therefore, it is possible to maintain the ease of attaching the present sensor by curving it according to the shape of the door end or the like.
(8) Further, the sensor of this example is subjected to water-repellent processing and / or oil-repellent processing on the surface. For this reason, as described above, there is an effect of reducing the possibility of malfunction due to moisture or oil.

(Second embodiment)
Next, a second embodiment will be described with reference to FIG. In addition, description is abbreviate | omitted about the structure similar to a 1st form example (other form examples are also the same).
FIG. 2A is a diagram schematically showing the internal configuration of the sensor main body 1A in the capacitance sensor of this example, and FIG. 2B is a diagram illustrating the first operating state of the sensor main body 1A (crushing by an object). 2 (c) is a diagram illustrating a first operation state of the sensor body 1A (a state in which the sensor body 1C is crushed from an oblique direction), and FIG. It is a figure which shows the 2nd operation state (state which was further crushed by the object) of the sensor main body.
In this example, when the sensor is pushed from the detection direction and deformed by contact with an object, the detection electrode A and the shield electrode S are first in contact with each other (FIG. 2B or FIG. 2C). ))), The contact of the object can be detected, and by further deformation, the detection electrode A, the detection electrode B, and the shield electrode S are in contact with each other (see FIG. 2D). Thus, the contact of the object can be detected.

  Next, FIG. 14A is a data example showing a change in the sensor output TP7 when the dielectric approaches the sensor body 1A of the present example. When the dielectric approaches the sensor body 1A, the sensor output TP7 increases as described above, and the proximity detection state is entered when the proximity detection threshold voltage is exceeded. When the dielectric further moves with respect to the detection surface of the sensor body 1A and comes into contact with the detection surface to bring the detection electrode A and the shield electrode S into contact with each other, the sensor output TP7 increases instantaneously. Thus, the proximity detection state is maintained (or, further, for example, it is determined that the object is in contact by the processing of the control circuit 50). Further, when the dielectric further moves and the detection electrode A, the detection electrode B, and the shield electrode S come into the second operation state, the sensor output TP7 is instantaneously decreased to substantially zero V, and touch detection is performed. It becomes a state. Thus, according to this sensor, the approach and contact of an object (dielectric material) can be detected continuously in real time, and the contact state can be detected in two stages.

  FIG. 14B is a data example showing a change in the sensor output TP7 when a non-dielectric material approaches the sensor body 1A. When the non-dielectric material approaches the sensor main body 1A, since there is no change in the capacitance, the sensor output TP7 is maintained at the value V0 corresponding to the reference voltage and does not enter the proximity detection state. However, when the dielectric further moves with respect to the detection surface of the sensor body 1A and comes into contact with the detection surface to bring the detection electrode A and the shield electrode S into contact with each other, the sensor output TP7 increases instantaneously. And the proximity detection state is reached (or, further, for example, it is determined that the object has touched by the processing of the control circuit 50). Further, when the dielectric further moves and the detection electrode A, the detection electrode B, and the shield electrode S come into the second operation state, the sensor output TP7 is instantaneously decreased to substantially zero V, and touch detection is performed. It becomes a state. As described above, according to the present sensor, contact of an object (non-dielectric material) can be detected in real time and in two stages.

  In this example (that is, in a configuration in which a threshold value is set as shown in FIG. 14), contact with an object is detected as approach when the first operating state is reached. However, for example, a second touch detection threshold voltage is set between the proximity detection threshold voltage and the maximum voltage (near the maximum voltage) to detect an increase in the sensor output TP7 to the maximum voltage. If so, for example, if the second touch detection threshold voltage is exceeded, a determination circuit that switches the determination result from the approach detection state to the touch detection state is provided, or the sensor If the control circuit 50 reads that the output TP7 has exceeded the second touch detection threshold voltage, the touch detection state and the control circuit 50 finally determine), and the contact of the object (first operation state) is determined. , It can be detected as contact, not as approach. However, since the proximity detection threshold voltage needs to be increased toward the fully closed side of the door as described with reference to FIG. 10, the second touch detection threshold is set in the range near the fully closed door. Setting the value voltage is difficult.

  FIG. 13 is a modification of the present embodiment (second embodiment), in which the second operation state is not achieved even when an object contacts and the sensor is pushed in (only the detection electrode A and the shield electrode S are in contact with each other). It is a figure explaining operation | movement of the case of a structure to be performed. Of these, FIG. 13A shows the case where the dielectric is approaching and contacting, and FIG. 13B is the case where the non-dielectric is approaching and contacting. In this aspect, the sensor output TP7 remains at the maximum voltage regardless of the degree of contact of the object.

(Third embodiment)
Next, a third embodiment will be described with reference to FIG.
FIG. 3A is a diagram schematically showing the internal configuration of the sensor body 1B in the capacitance sensor of this example, and FIG. 3B is a diagram illustrating the first operating state of the sensor body 1B (crushing by an object). 3 (c) is a diagram illustrating a second operating state (a state in which the sensor body 1B is further crushed by an object).
In this example, the sensor is pushed from the detection direction and deformed by the contact of the object, so that the detection electrode B and the shield electrode S are first in a first operation state (see FIG. 3B). The contact of the object can be detected, and further deformation causes the detection electrode A, the detection electrode B, and the shield electrode S to be in the second operating state (see FIG. 2C), and the contact of the object is This is a mode that enables detection.

  When the detection electrode B and the shield electrode S are in contact with each other, the sensor output TP7 is instantaneously reduced to substantially zero V as in the case where the detection electrodes A and B are in contact with each other. For this reason, the change of the sensor output TP7 in the case of this example is the same as that of the first embodiment shown in FIGS. Therefore, also in this example, the approach and contact of the object (dielectric material) can be detected continuously in real time, and the contact state can be detected in two stages. Further, contact of an object (non-dielectric material) can be detected in real time and in two stages.

(Fourth embodiment)
Next, a fourth embodiment will be described with reference to FIG.
FIG. 6A is a diagram illustrating an entire configuration of a sensor when a disconnection detection function using a capacitor is provided (fourth embodiment). In this example, at least the detection electrode B is used as the sensor body 1C having a configuration in which a capacitor 61 having a capacitance larger than the capacitance between the detection electrode A and the detection electrode B is connected between the tips of the detection electrode A and the detection electrode B. The disconnection can be detected. In this case, when the detection electrode B is disconnected, the capacitance between the detection electrode B and the ground decreases (charge emission decreases), so that the output TP3 of the difference circuit 23 increases and the final output TP7 is compared with the reference voltage V0. Thus, the state is constantly increased (in the case of the configuration of the first embodiment, the approach detection state is maintained). For this reason, if this state is determined by, for example, the control circuit 50 (for example, if the approach detection state continues for a long time beyond a preset time, a process for determining a disconnection will be executed). The disconnection of the electrode B can be detected, and the user can be notified that the disconnection has occurred.

(Fifth embodiment)
Next, a fifth embodiment will be described with reference to FIGS. 6B and 6C.
This example is a mode in which a disconnection detection function using a folded electric wire (disconnection detection electric wire B2) connected to the detection electrode B is provided. FIG. 6B is a diagram illustrating the overall configuration of the sensor, and FIG. 6C is a cross-sectional view illustrating the sensor main body 1D.
In this example, the disconnection detection electric wire B2 is provided so as to extend the conducting wire 5 of the detection electrode B, for example. The disconnection detection electric wire B2 is formed of, for example, the same material as the conductor 5 (may be an integral product), and is folded back from the detection electrode B outside the tip of the sensor body 1D as shown in FIG. 6B. The sensor body 1D is disposed along the longitudinal direction in the sensor body 1D (for example, in the low dielectric constant insulating material 3 as shown in FIG. 6C). And the connection edge part of this electric wire B2 for disconnection detection is derived | led-out from the base end of sensor main body 1D similarly to another electrode, and is connected to the detection circuit 20A.

Here, the detection circuit 20A is different from the detection circuit 20 of the first embodiment in that it further includes a disconnection determination circuit 70 as shown in FIG. The disconnection determination circuit 70 includes a determination circuit 73 having input terminals respectively connected to the detection electrode B or the disconnection detection electric wire B2, and a serial connection between one input terminal of the determination circuit 73 and the disconnection detection electric wire B2. And an open / close switch 72 and a resistor 73 connected to each other. The determination circuit 73 closes the switch 72 at an appropriate time (for example, when the door is not opened or closed) and monitors the voltage between the input terminals, thereby conducting the detection electrode B and the disconnection detection electric wire B2. The state is determined, and if it is a non-conductive state, it is determined that the detection electrode B is disconnected.
For this reason, also in this example, the disconnection of the detection electrode B can be detected, and it is possible to notify the user or the like that the disconnection has occurred. However, in the case of this example, the disconnection determination circuit 70 needs to be provided separately, and therefore the fourth embodiment is particularly advantageous in terms of cost.

The present invention is not limited to the above-described embodiments, and various modifications and applications are possible.
For example, the determination circuit 29 is not composed of the comparator as described above, and can be realized by a determination process in the control circuit 50, for example. Further, the subtraction circuit 27 and the amplification circuit 28 may be provided as necessary.
In the above-described embodiment, the combination and order of the electrodes that are brought into contact with each other by being pushed by the object have been described as being constant, but depending on the position where the object is in contact and the direction of the force, There may be a configuration in which the combination or order changes.

(A) is a figure which shows typically the internal structure of the sensor main body of an electrostatic capacitance sensor, (b) is a figure which shows the 1st operation state of a sensor main body, (c) is the 2nd operation | movement of a sensor main body. It is a figure which shows a state. (A) is a figure which shows typically the internal structure of a sensor main body (2nd form example), (b), (c) is a figure which shows the 1st operation state of a sensor main body, (d) is a sensor. It is a figure which shows the 2nd operation state of a main body. (A) is a figure which shows typically the internal structure of a sensor main body (3rd example), (b) is a figure which shows the 1st operation state of a sensor main body, (c) is the 2nd of a sensor main body. It is a figure which shows an operation state. (A) is a perspective view which shows the whole sensor main body, (b) is a figure which shows a sensor main body and its periphery structure. It is a figure which shows the specific example (example of actual structure) of the internal structure of a sensor main body. (A) is a figure which shows the sensor whole structure of a 4th form example, (b) is a figure which shows the sensor whole structure of a 5th form example, (c) is a cross section which shows the sensor main body of a 5th form example. FIG. It is a block diagram which shows the outline of the pinching detection apparatus (a detection circuit etc. are included) containing the electrostatic capacitance sensor of this example. It is a circuit diagram which shows the specific example of a detection circuit (until a smoothing circuit). It is a circuit diagram which shows the specific example of a detection circuit (after a smoothing circuit) and a determination circuit. It is a figure explaining a proximity detection area and a touch detection area. It is a timing chart explaining operation | movement of a detection circuit. It is a figure which shows the example of data explaining operation | movement of a detection circuit. It is a figure which shows the example of data explaining operation | movement of a detection circuit. It is a figure which shows the example of data explaining operation | movement of a detection circuit.

Explanation of symbols

1,
1A, 1B, 1C, 1D Sensor body 2, 3 Low dielectric constant insulating material (non-conductive flexible body)
4, 5, 6 Conductor 10 Sliding door (opening / closing body)
20, 20A Detection circuit 61 Capacitor S Shield electrode (conductive flexible body)
A Detection electrode (main electrode, conductive flexible body)
B Detection electrode (Comparative electrode, conductive flexible body)

Claims (9)

A code type sensor that detects a change in capacitance,
A plurality of detection electrodes for detecting a change in capacitance and a substantially U-shaped cross section orthogonal to the longitudinal direction of the sensor in order to limit the detection range of the capacitance, and an opening in the detection direction And a shield electrode facing the sensor, along the longitudinal direction of the sensor,
The detection electrode is disposed at a position close to the opening in the shield electrode and a position far from the opening in the shield electrode,
The detection electrode and the shield electrode are formed of a conductive flexible body,
When the detection electrodes are kept apart from each other and the detection electrodes and the shield electrodes are separated from each other in a natural state, and the sensor is pushed from the detection direction by contact with an object, the detection electrodes or The detection electrode and the shield electrode are integrally connected by a non-conductive flexible body so that the detection electrode and the shield electrode are in contact with each other and the contact of the object can be detected. Capacitance sensor. The detection electrode is disposed at a position close to the opening in the shield electrode, and a position far from the opening in the shield electrode, between the main electrode and the shield electrode. The electrostatic capacitance sensor according to claim 1, further comprising a comparison electrode. When the sensor is pushed and deformed from the detection direction by the contact of the object, the main electrode and the comparison electrode are first brought into contact with each other to detect the contact of the object, and further deformed, the main electrode, 3. The capacitance sensor according to claim 2, wherein the comparison electrode and the shield electrode are in contact with each other so that contact of an object can be detected. When the sensor is pushed and deformed from the detection direction by the contact of the object, the main electrode and the shield electrode first contact each other to detect the contact of the object, and further deformed, the main electrode, 3. The capacitance sensor according to claim 2, wherein the comparison electrode and the shield electrode are in contact with each other so that contact of an object can be detected. When the sensor is pushed and deformed by the contact of the object from the detection direction, first, the comparison electrode and the shield electrode come into contact with each other to detect the contact of the object, and further deformed, the main electrode, 3. The capacitance sensor according to claim 2, wherein the comparison electrode and the shield electrode are in contact with each other so that contact of an object can be detected. A capacitor having a capacitance larger than the capacitance between the main electrode and the comparison electrode is connected between the main electrode and the tip of the comparison electrode, so that at least disconnection of the comparison electrode can be detected. The capacitance sensor according to any one of claims 2 to 5. A conductive wire made of a material having a smaller electric resistance than the conductive flexible body is disposed along the longitudinal direction of the sensor in the detection electrode or / and the outer peripheral surface of the shield electrode.
The capacitance sensor according to any one of claims 1 to 6, wherein an installation position of the conducting wire is set near a neutral surface of the sensor with respect to bending in a plane orthogonal to the detection direction. The electrostatic capacity sensor according to any one of claims 1 to 7, wherein the surface is water-repellent. The electrostatic capacity sensor according to any one of claims 1 to 7, wherein an oil repellent finish is applied to the surface.