JP5326042B2 - Capacitance type sensor device and capacitance measuring device for capacitance type sensor - Google Patents

Capacitance type sensor device and capacitance measuring device for capacitance type sensor Download PDF

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JP5326042B2
JP5326042B2 JP2012509510A JP2012509510A JP5326042B2 JP 5326042 B2 JP5326042 B2 JP 5326042B2 JP 2012509510 A JP2012509510 A JP 2012509510A JP 2012509510 A JP2012509510 A JP 2012509510A JP 5326042 B2 JP5326042 B2 JP 5326042B2
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capacitance
voltage
capacitive sensor
electrode
measuring
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JPWO2011125725A1 (en
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哲好 柴田
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東海ゴム工業株式会社
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01LMEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00Measuring force or stress, in general
    • G01L1/14Measuring force or stress, in general by measuring variations in capacitance or inductance of electrical elements, e.g. by measuring variations of frequency of electrical oscillators
    • G01L1/142Measuring force or stress, in general by measuring variations in capacitance or inductance of electrical elements, e.g. by measuring variations of frequency of electrical oscillators using capacitors
    • G01L1/146Measuring force or stress, in general by measuring variations in capacitance or inductance of electrical elements, e.g. by measuring variations of frequency of electrical oscillators using capacitors for measuring force distributions, e.g. using force arrays
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01DMEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/12Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
    • G01D5/14Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
    • G01D5/24Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying capacitance
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01DMEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/12Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
    • G01D5/14Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
    • G01D5/24Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying capacitance
    • G01D5/2405Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying capacitance by varying dielectric

Abstract

Provided is a capacitance-type sensor device capable of accurately measuring a capacitance while being reduced in size. The capacitance-type sensor device comprises: a voltage applying element (21) connected in series to the first electrode (11) of a capacitance-type sensor (10) and applying a periodic rectangular wave voltage to the capacitance-type sensor (10); a rectifier (22a) connected to the second electrode (12) of the capacitance-type sensor (10) and rectifying electrical charges charged to and discharged from the capacitance-type sensor (10) when the voltage applying element (21) applies the periodic rectangular wave voltage; a smoothing capacitor (C1) connected in parallel with the rectifier (22a); current measuring shunt resistor (R1) connected in parallel with the smoothing capacitor (C1); and a voltage measuring unit (220) for measuring voltage (Vx) between both ends of the current measuring shunt resistor (R1).

Description

  The present invention relates to a capacitance type sensor device that can measure the capacitance of a capacitance type sensor, and a capacitance measurement device of a capacitance type sensor.

  As an apparatus for measuring a change in capacitance, there are apparatuses described in Japanese Patent Application Laid-Open No. 2006-177895 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2008-306679 (Patent Document 2). Moreover, although it does not measure a change in capacitance, there is a device described in Japanese Patent Application Laid-Open No. 2002-63999 (Patent Document 3) as a device for measuring a potential.

JP 2006-177895 A JP 2008-306679 A JP 2002-63999 A

  Here, if the circuit for converting the capacitance into voltage is large, the capacitance-voltage conversion circuit cannot be provided at the installation position of the capacitance-type sensor, and the position away from the capacitance-type sensor. Must be installed in. Then, the wiring that connects the capacitive sensor and the capacitive voltage conversion circuit becomes long, and the capacitance measurement accuracy may be reduced due to an increase in the wiring capacitance and noise on the wiring. Therefore, in order to enable highly accurate measurement of capacitance, a capacitance-voltage conversion circuit that is less susceptible to the above-described influence is required. Therefore, if the capacitance voltage conversion circuit can be reduced in size, the capacitance type sensor and the capacitance voltage conversion circuit can be formed as an integrated unit. The wiring connecting the circuit can be made very short. That is, the wiring capacitance can be reduced and the influence of noise on the wiring can be reduced.

  However, since the capacitance-voltage conversion circuit constituting the measuring device described in Patent Documents 1 and 2 uses various elements, the capacitance-type sensor and the capacitance-voltage conversion circuit are integrated into a unit. Cannot be done and has the above-mentioned problems. Note that the device for measuring a potential described in Patent Document 3 is used for measuring a change in potential, and is not a device for measuring a capacitance.

  The present invention has been made in view of such circumstances, and can measure the capacitance with high accuracy while reducing the size of the capacitance-voltage conversion circuit that converts the capacitance into voltage. It is an object of the present invention to provide a capacitance type sensor device and a capacitance type measurement device for a capacitance type sensor.

  As a result of diligent research, the present inventors have come up with the idea that the capacitance of a capacitor can be measured if the amount of charge discharged can be measured after applying a constant voltage to the capacitor and charging. That is, in the present invention, since the amount of charge for one charge / discharge is extremely small, charge / discharge is repeated using a transmitter that generates a rectangular wave, and charge / discharge is performed to obtain a charge amount (current) per unit time. The flow of electric charge was made unidirectional with a rectifier, only the intermittently discharged electric charge was smoothed (integrated) with a capacitor, and the electric charge amount was measured as a voltage with a current measuring shunt resistor. Specifically, it is as follows.

(Capacitive sensor device)
A first invention according to a capacitance type sensor device includes first and second electrodes provided to face each other at a distance, and the first and second electrodes are applied in response to an external force applied or an operator approaching or contacting. A capacitance-type sensor in which the capacitance between the electrodes changes, a voltage application means connected in series to the first electrode of the capacitance-type sensor, and applying a periodic rectangular wave voltage to the capacitance-type sensor; A rectifier connected to the second electrode of the capacitive sensor and rectifying the charge charged / discharged to the capacitive sensor when the voltage application means applies a periodic rectangular wave voltage, and connected in parallel to the rectifier. A smoothing capacitor, a current measuring shunt resistor connected in parallel to the smoothing capacitor, and voltage measuring means for measuring a voltage across the current measuring shunt resistor.
The capacitance type sensor is a capacitance type sensor formed in a surface shape, and the first and second electrodes are provided facing each other with a distance in the surface normal direction of the capacitance type sensor. An electrode, a dielectric layer provided between the first and second electrodes, and an insulating layer provided on the surface side of the capacitive sensor, and a conductor to the surface of the capacitive sensor The electrostatic capacitance between the first and second electrodes changes according to the approach or contact state of the operator.
The rectifier, the smoothing capacitor, and the shunt resistor for current measurement are composed of a plurality connected to a plurality of locations of the second electrode, and the plurality of rectifiers are connected to different positions of the second electrode.
The electrostatic capacitance type sensor device is configured to detect the electrostatic capacity based on the both-end voltages of the current measuring shunt resistors measured by the voltage measuring unit when the rectangular wave voltage is applied by the voltage applying unit. The apparatus further includes state estimation means for estimating at least one of an approach position, a contact position, and a contact state of an operator approaching or contacting the capacitive sensor.

Here, in the capacitive sensor device of the present invention, the rectifier, the smoothing capacitor, and the shunt resistor for current measurement become a capacitive voltage conversion circuit that converts the electrostatic capacitance of the capacitive sensor into a voltage. That is, according to the present invention, the capacitance-voltage conversion circuit has a very simple configuration, specifically, a configuration with a very small number of elements. Therefore, the capacitance-voltage conversion circuit in the capacitance type sensor device can be formed very small. Here, there is a possibility that the capacitance measurement accuracy may be lowered due to the simple configuration, but the capacitance can be measured with high accuracy by applying the rectangular wave voltage by the voltage applying means. It became so. In other words, the present invention applies a concept of measuring the amount of charge to be charged / discharged at a constant voltage to an apparatus for measuring capacitance, and is small in size by a combination of a simple rectangular wave voltage applying means and rectifying and smoothing means. However, the capacitance of the capacitance type sensor can be measured with high accuracy.
In the above case, the operator configures the electrode, and the electrode located on the surface side of the first electrode and the second electrode and the operator itself form a capacitor. As a result, the capacitance of the capacitor formed by the first electrode and the second electrode is affected. Therefore, by measuring the current flowing through the second electrode, it is possible to grasp the approach, contact, or degree of contact of the operator. Note that the contact state is used to include the presence or absence of contact and the degree of contact.
Here, due to the influence of the resistance component of the second electrode, the voltages output from the plurality of capacitance voltage conversion circuits have different values depending on the approach position, contact position, or contact state of the operator. By utilizing this, a plurality of output side capacitance voltage conversion circuits are connected to different positions of the second electrode, and are measured by the voltage measurement means of each output side capacitance voltage conversion circuit. The approach position, the contact position, or the contact state of the operator can be calculated by the voltage between both ends.

In the capacitance type sensor device of the present invention, the voltage applying means can use an element for applying a voltage such as an oscillator, or can use the timer output of the oscillation circuit and the control unit (microcomputer). The voltage measuring means can also measure the voltage across the shunt resistor for current measurement itself, or can measure the voltage input via the amplifier.
Further, the second invention related to the capacitive sensor device includes first and second electrodes provided to face each other at a distance, and the first sensor is attached to the first sensor when external force is applied or an operator approaches or contacts. , A capacitance type sensor in which the capacitance between the second electrodes changes, and a series connected to the first electrode of the capacitance type sensor, and applying a periodic rectangular wave voltage to the capacitance type sensor And a charge applied to the capacitive sensor when the voltage applying means applies the periodic rectangular wave voltage. A smoothing capacitor connected in parallel to the rectifier, a current measuring shunt resistor connected in parallel to the smoothing capacitor, and a voltage measuring means for measuring a voltage across the shunt resistor for current measurement. Prepare.
The capacitance type sensor is a capacitance type sensor formed in a surface shape, and the first and second electrodes provided at a distance in the surface direction of the capacitance type sensor, and the static sensor. An insulating layer provided on the surface side of the capacitive sensor, and depending on the approach or contact state of the operator as a conductor to the surface of the capacitive sensor, between the first and second electrodes This is a sensor whose capacitance changes.
The rectifier, the smoothing capacitor, and the shunt resistor for current measurement are composed of a plurality connected to a plurality of locations of the second electrode, and the plurality of rectifiers are connected to different positions of the second electrode.
The electrostatic capacitance type sensor device is configured to detect the electrostatic capacity based on the both-end voltages of the current measuring shunt resistors measured by the voltage measuring unit when the rectangular wave voltage is applied by the voltage applying unit. The apparatus further includes state estimation means for estimating at least one of an approach position, a contact position, and a contact state of an operator approaching or contacting the capacitive sensor.
In this case, when the operator configures the electrode, the first electrode and the operator themselves form the first capacitor, and the second electrode and the operator themselves form the second capacitor. As a result, the capacitance of the capacitor formed by the first electrode and the second electrode is affected. Therefore, by measuring the current flowing through the second electrode, it is possible to grasp the approach, contact, or degree of contact of the operator.
Due to the influence of the resistance component of the second electrode, the voltages output from the plurality of capacitance-voltage conversion circuits have different values depending on the approach position, contact position, or contact state of the operator. By utilizing this, a plurality of output side capacitance voltage conversion circuits are connected to different positions of the second electrode, and are measured by the voltage measurement means of each output side capacitance voltage conversion circuit. The approach position, the contact position, or the contact state of the operator can be calculated by the voltage between both ends.

  Further, the voltage measuring means is a voltage across the shunt resistor for current measurement based on the charging voltage of the capacitive sensor, the frequency of the rectangular wave voltage applied by the voltage applying means, and the resistance value of the shunt resistor for current measurement. May be measured as the capacitance of the capacitive sensor. Accordingly, it is possible to reliably measure the voltage obtained by converting the capacitance of the capacitance type sensor and calculate the capacitance of the capacitance type sensor.

  Further, the capacitive sensor, the voltage applying means, the rectifier, the smoothing capacitor, and the current measuring shunt resistor may be formed as an integrated unit. Thus, when formed as an integral unit, in particular, a part other than the capacitive sensor in the capacitive sensor device, in particular, a capacitive voltage conversion circuit that converts the electrostatic capacity into a voltage. It is desired to be small. By applying the present invention, since the components of the capacitance-voltage conversion circuit are simple with only the rectifier diode, the smoothing capacitor, and the current measurement shunt resistor, the capacitance-voltage conversion circuit can be reduced in size.

  At this time, the first and second electrodes of the capacitance type sensor are electrodes having flexibility and stretchability, and the capacitance type sensor has flexibility and stretchability. It is advisable to have such properties. That is, it means that the capacitive sensor has a flexible shape. As a result, the capacitive sensor can be used for various applications. When the capacitive sensor and the capacitive voltage conversion circuit are formed as an integral unit in the capacitive sensor device, and the capacitive sensor is flexible, By downsizing the capacitance-voltage conversion circuit in the capacitance-type sensor device, it is possible to make it relatively difficult to feel the firmness of the circuit board including the capacitance-voltage conversion circuit. Therefore, according to the present invention, the entire unit including the capacitive sensor and the capacitive voltage conversion circuit can be recognized as a flexible shape.

(Capacitance measuring device for capacitive sensor)
In the above description, the case where the present invention is grasped as a capacitive sensor device has been described. However, in addition to this, only the measurement device portion of the capacitive sensor device can be extracted and grasped.

In other words, a first invention relating to a capacitance measuring device of a capacitance type sensor includes first and second electrodes provided to face each other at a distance, and can be used to apply an external force or approach or contact an operator. A voltage measuring device for measuring the capacitance of a capacitance type sensor in which the capacitance between the first and second electrodes changes, and applying a periodic rectangular wave voltage to the capacitance type sensor A rectifier connected to the second electrode of the capacitive sensor and rectifying charges charged and discharged to the capacitive sensor when the voltage applying means applies a periodic rectangular wave voltage; Are connected in parallel to each other, a current measuring shunt resistor connected in parallel to the smoothing capacitor, and voltage measuring means for measuring a voltage across the current measuring shunt resistor.
The capacitance type sensor is a capacitance type sensor formed in a surface shape, and the first and second electrodes are provided facing each other with a distance in the surface normal direction of the capacitance type sensor. An electrode, a dielectric layer provided between the first and second electrodes, and an insulating layer provided on the surface side of the capacitive sensor, and a conductor to the surface of the capacitive sensor The electrostatic capacitance between the first and second electrodes changes according to the approach or contact state of the operator.
The rectifier, the smoothing capacitor, and the shunt resistor for current measurement are composed of a plurality connected to a plurality of locations of the second electrode, and the plurality of rectifiers are connected to different positions of the second electrode.
The capacitance-type measuring device is configured to detect the electrostatic capacitance based on the both-end voltages of the current measuring shunt resistors measured by the voltage measuring unit when the rectangular wave voltage is applied by the voltage applying unit. The apparatus further includes state estimation means for estimating at least one of an approach position, a contact position, and a contact state of an operator approaching or contacting the capacitive sensor.
The second invention according to the capacitance measuring device of the capacitance type sensor includes first and second electrodes provided to face each other at a distance, and can be used for applying external force or approaching or contacting an operator. A measurement device for measuring the capacitance of a capacitive sensor in which the capacitance between the first and second electrodes changes accordingly, and connected in series to the first electrode of the capacitive sensor Voltage applying means for applying a periodic rectangular wave voltage to the capacitive sensor, and the voltage applying means connected to the second electrode of the capacitive sensor, wherein the voltage applying means is the periodic rectangular wave voltage. A rectifier that rectifies the charge charged / discharged to the capacitive sensor, a smoothing capacitor connected in parallel to the rectifier, a shunt resistor for current measurement connected in parallel to the smoothing capacitor,
Voltage measuring means for measuring a voltage across the shunt resistor for current measurement.
The capacitance type sensor is a capacitance type sensor formed in a surface shape, and the first and second electrodes provided at a distance in the surface direction of the capacitance type sensor, and the static sensor. An insulating layer provided on the surface side of the capacitive sensor, and depending on the approach or contact state of the operator as a conductor to the surface of the capacitive sensor, between the first and second electrodes This is a sensor whose capacitance changes.
The rectifier, the smoothing capacitor, and the shunt resistor for current measurement are composed of a plurality connected to a plurality of locations of the second electrode, and the plurality of rectifiers are connected to different positions of the second electrode.
The capacitance-type measuring device is configured to detect the electrostatic capacitance based on the both-end voltages of the current measuring shunt resistors measured by the voltage measuring unit when the rectangular wave voltage is applied by the voltage applying unit. The apparatus further includes state estimation means for estimating at least one of an approach position, a contact position, and a contact state of an operator approaching or contacting the capacitive sensor.

  Thereby, there can exist the same effect as the effect in the electrostatic capacitance type sensor apparatus mentioned above. In addition, other characteristic portions in the above-described capacitance type sensor device can be applied to the capacitance measuring device, and the same effect can be obtained.

First Embodiment: (a) is a plan view of a capacitive sensor device. (B) is a front view of a capacitive sensor device. 1 is an electric circuit diagram of a capacitive sensor device. 2nd embodiment: It is a typical plane block diagram of an electrostatic capacitance type sensor apparatus. It is a timing chart of control operation by a switching control part. FIG. 9 is an electric circuit diagram showing a configuration of an input side switching circuit 311. FIG. 3rd embodiment: It is sectional drawing of an electrostatic capacitance type sensor apparatus. It is a top view of an electrostatic capacitance type sensor device. It is sectional drawing of the electrostatic capacitance type sensor apparatus in the state which increased the pressing force of the finger | toe. Fourth Embodiment: It is a perspective view of a capacitive sensor device. 5th embodiment: It is an electric circuit diagram of an electrostatic capacitance type sensor apparatus. It is AA sectional drawing of FIG. 6th embodiment: It is an electric circuit diagram of a capacitive sensor apparatus. It is BB sectional drawing of FIG. 7th embodiment: It is an electrical circuit diagram of a capacitive sensor device. It is CC sectional drawing of FIG. It is a graph which shows the output voltage of a 1st, 2nd electrostatic capacitance voltage conversion circuit.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying a capacitance type sensor device and a capacitance measuring device of the present invention will be described below with reference to the drawings.
<First embodiment>
The capacitive sensor device of the first embodiment will be described with reference to FIGS. 1 and 2. The capacitance type sensor device can be used as, for example, a pressure sensor, or can be used for measuring a tension applied to a seat belt that is attached to a seat belt of a vehicle.

  The capacitance type sensor device, when viewed as a component unit, includes each component unit of the capacitance type sensor unit 1, the power source 100, and the voltage measuring device 200. Therefore, first, a part mainly related to the shape of the capacitive sensor unit 1 will be described with reference to FIGS. 1A and 1B, and later, an electric circuit of the capacitive sensor device will be described with reference to FIG. This will be described in detail.

  The capacitive sensor unit 1 includes a capacitive sensor 10, a circuit board 20, and a wiring portion 30, and these are formed as an integral unit. In the present embodiment, the capacitance type sensor 10 has a flexible and stretchable property, and is formed of a soft material such as rubber. However, in the present invention, the capacitive sensor 10 can be applied to a sensor other than one having flexibility.

  And the capacitive sensor 10 is formed in the surface shape, as shown to Fig.1 (a) (b). The capacitance type sensor 10 includes first and second electrodes 11 and 12 which are provided to face each other at a distance in a surface normal direction (vertical direction in FIG. 1B). The dielectric layer 13 provided between the electrodes 11 and 12 and the insulating layers 14 and 15 provided so as to cover the surface on the second electrode 12 side and the back surface on the first electrode 11 side are configured. The distance between the first electrode 11 and the second electrode 12, the electrode area, or both change according to the applied external force, and the change between the first electrode 11 and the second electrode 12 is accompanied by this change. The capacitance changes. Since it is well known that the capacitance is proportional to the separation distance, the electrode area, or both, detailed description is omitted.

  The first and second electrodes 11 and 12 constituting the capacitance type sensor 10 are made of the same material and have the same shape. Specifically, the first and second electrodes 11 and 12 are formed in a thin-film rectangular shape. The material of the 1st, 2nd electrodes 11 and 12 is shape | molded by mix | blending a conductive filler in an elastomer. The first and second electrodes 11 and 12 are flexible and extendable and contractible.

  Examples of the elastomer constituting the first and second electrodes 11 and 12 include silicone rubber, ethylene-propylene copolymer rubber, natural rubber, styrene-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber, acrylic rubber, epichlorohydride. Rubber, chlorosulfonated polyethylene, chlorinated polyethylene, urethane rubber, etc. can be applied. Moreover, the electroconductive filler mix | blended with the 1st, 2nd electrodes 11 and 12 should just be the particle | grains which have electroconductivity, For example, fine particles, such as a carbon material and a metal, can be applied.

  The dielectric layer 13 is formed of an elastomer, and has flexibility and a stretchable property, like the first and second electrodes 11 and 12. Examples of the elastomer constituting the dielectric layer 13 include silicone rubber, acrylonitrile-butadiene copolymer rubber, acrylic rubber, epichlorohydrin rubber, chlorosulfonated polyethylene, chlorinated polyethylene, and urethane rubber. The dielectric layer 13 has a set thickness and is formed in a rectangular shape similar to the first and second electrodes 11 and 12. The insulating layers 14 and 15 are flexible and extendable and contractible, like the first and second electrodes 11 and 12. As the elastomer constituting the insulating layers 14 and 15, for example, the material described as the elastomer constituting the dielectric layer 13 is applied.

  The capacitance type sensor 10 including the first and second electrodes 11 and 12, the dielectric layer 13, and the insulating layers 14 and 15 described above has an arbitrary shape having a predetermined thickness as a whole (in FIG. 1A). For example, it is formed as a rectangular shape). Further, the capacitive sensor 10 has flexibility and a property of being stretchable.

  When the capacitive sensor 10 receives a compressive force in the surface normal direction of the capacitive sensor 10, the dielectric layer 13 compresses and deforms in the surface normal direction, thereby The separation distance between the two electrodes 11 and 12 is shortened. In this case, the capacitance of the capacitive sensor 10 increases. When the capacitive sensor 10 receives a tensile force in the surface tangential direction of the capacitive sensor 10, the dielectric layer 13 expands and deforms in the surface tangential direction, so that the first and second electrodes The electrode areas of 11 and 12 are increased. Also in this case, the capacitance of the capacitive sensor 10 increases. Thus, when the capacitive sensor 10 receives an external force, the capacitance of the capacitor formed by the first electrode 11 and the second electrode 12 changes according to the external force.

  The circuit board 20 includes a voltage application element 21 and a capacitance / voltage conversion circuit 22, which are formed on the same board. The voltage application element 21 is an element (for example, an oscillator) that applies a periodic rectangular wave voltage to the capacitive sensor 10. In this embodiment, the case where an oscillator as the voltage applying element 21 is used as a means for applying the rectangular wave voltage is taken as an example. However, for example, a timer output of an oscillation circuit and a control unit (microcomputer) can be used. It can also be used.

  The capacitance-voltage conversion circuit 22 is a circuit that can extract the capacitance as a voltage by converting the capacitance of the capacitance-type sensor 10 into a voltage. As an outline, the capacitance voltage conversion circuit 22 is on the output side of the capacitance type sensor 10 when a periodic rectangular wave voltage is applied to the first electrode 11 of the capacitance type sensor 10. This is a circuit that converts the current charged / discharged by the second electrode 12 into a voltage and outputs the voltage. Detailed description of the voltage applying element 21 and the capacitance-voltage conversion circuit 22 will be described later with reference to FIG.

The wiring unit 30 electrically connects the capacitive sensor 10 and the circuit board 20. The wiring unit 30 has substantially the same configuration as that of the capacitive sensor 10. The wiring part 30 includes first and second electrodes 31 and 32 and insulating layers 33, 34 and 35. The first and second electrodes 31 and 32 are formed of the same material integrally with the first and second electrodes 11 and 12 of the capacitance type sensor 10, respectively. It is connected. The intermediate insulating layer 33 is formed of the same material integrally with the dielectric layer 13 of the capacitive sensor 10. The insulating layers 34 and 35 are formed of the same material integrally with the insulating layers 14 and 15 of the capacitive sensor 10. The first electrode 31 of the wiring part 30 is electrically connected to the voltage applying element 21 of the circuit board 20, and the second electrode 32 of the wiring part 30 is electrically connected to the capacitance / voltage conversion circuit 22 of the circuit board 20. It is connected.
The capacitive sensor unit 1 described above is connected to the power supply 100 and the voltage measuring instrument 200 via a harness.

  Next, an electric circuit of the capacitive sensor device will be described in detail with reference to FIG. Here, since the capacitance type sensor 10 functions as a variable capacitance, in FIG. 2, the capacitance type sensor 10 is illustrated as a variable capacitance.

  As shown in FIG. 2, the capacitive sensor device includes a capacitive sensor 10 and a capacitance measuring device 2 when viewed from the functional viewpoint of an electric circuit. The capacitance measuring device 2 of the capacitance type sensor device includes a power source 100, a voltage applying element 21, a capacitance / voltage conversion circuit 22, and a voltage measuring device 200.

  The power source 100 is a DC power source. The voltage application element 21 is an element that generates a periodic rectangular wave voltage, and applies the rectangular wave voltage to the capacitive sensor 10. Specifically, the output terminal of the voltage application element 21 is connected to the first electrode 11 of the capacitive sensor 10, and the ground terminal of the voltage application element 21 is connected to the negative electrode side of the power supply 100. A voltage is applied to the power supply terminal 21 from the power supply 100. The voltage applying element 21 generates a periodic rectangular wave voltage by being connected in this way. The voltage applied by the voltage applying element 21 is, for example, a frequency of 250 kHz, a maximum voltage of 5 V, and an ON duty ratio of 50%. Of course, it is possible to appropriately change the frequency, the maximum voltage, and the ON duty ratio.

  The capacitance-voltage conversion circuit 22 constituting the capacitance measuring device 2 includes a rectifier 22a, a smoothing capacitor C1, and a current measuring shunt resistor R1. The rectifier 22 a is connected to the output side of the capacitance type sensor 10, and the capacitance is applied when the voltage application element 21 applies a periodic rectangular wave voltage to the first electrode 11 of the capacitance type sensor 10. The charge charged and discharged on the second electrode 12 of the mold sensor 10 is rectified. The rectifier 22a includes a first diode D1 and a second diode D2. The first diode D1 is connected in series to the capacitive sensor 10, and the second diode D2 is connected in parallel to the capacitive sensor 10. Specifically, the anode of the first diode D1 is connected to the second electrode 12 of the capacitive sensor 10. The anode of the second diode D2 is connected to the negative electrode side of the power supply 100, and the cathode of the second diode D2 is connected to the second electrode 12 of the capacitive sensor 10 and the anode of the first diode D1.

  Accordingly, when the rectangular wave voltage of the voltage applying element 21 is ON, the second electrode 12 of the capacitive sensor 10 is charged through the second diode D2. On the other hand, when the rectangular wave voltage of the voltage applying element 21 is OFF, the electric charge is discharged from the second electrode 12 of the capacitive sensor 10 via the first diode D1.

  The smoothing capacitor C1 is connected in parallel to the output side of the rectifier 22a, and smoothes the current flowing through the rectifier 22a. That is, one end of the smoothing capacitor C1 is connected to the cathode of the first diode D1, and the other end is connected to the anode of the second diode D2. As described above, since the flow of charge differs between the rectifier 22a when the second electrode 12 of the capacitive sensor 10 is charged and discharged, the time change of the current on the output side of the rectifier 22a is intermittent. It becomes a shape. Therefore, the smoothing capacitor C1 has a role of smoothing the rectangular wave current.

  The current measuring shunt resistor R1 is connected in parallel to the output side of the smoothing capacitor C1. That is, both ends of the current measuring shunt resistor R1 are connected to both ends of the smoothing capacitor C1, respectively. Here, since all the discharge charges due to the second electrode 12 of the capacitive sensor 10 pass through the current measuring shunt resistor R1, the capacitance type is measured by measuring the voltage Vx across the current measuring shunt resistor R1. The discharge current by the second electrode 12 of the sensor 10 can be measured.

  The voltage measuring instrument 200 constituting the capacitance measuring device 2 includes a voltage amplifier 210 and a capacitance calculating unit 220 (corresponding to “voltage measuring means” of the present invention). The voltage amplifier 210 is connected in parallel to the output side of the current measuring shunt resistor R1, and amplifies the voltage Vx across the current measuring shunt resistor R1. In addition, although the electrostatic capacitance measuring apparatus 2 in the present embodiment is configured to include the voltage amplifier 210, it may be configured to include only the electrostatic capacitance calculation unit 220 without including the voltage amplifier 210.

  The capacitance calculating unit 220 measures the voltage Vx across the current measuring shunt resistor R1 amplified by the voltage amplifier 210, and calculates the capacitance Cx of the capacitive sensor 10 from the measured voltage Vx across the measured voltage Vx. . Here, the both-ends voltage Vx of the current measuring shunt resistor R1 is expressed as in Expression (1). In the equation (1), (V−Vf) corresponds to a charging voltage by the capacitive sensor 10 when a voltage is applied by the voltage applying element 21.

[Equation 1]
Vx = Cx ・ (V−Vf) ・ Freq ・ R1 (1)
Vx: Voltage across the shunt resistor R1 for current measurement
Cx: Variable capacitance of the capacitance type sensor 10
V: Maximum voltage applied by the voltage applying element 21
Freq: frequency of the rectangular wave voltage applied by the voltage applying element 21
Vf: Forward voltage of the first and second diodes D1 and D2
R1: Shunt resistor for current measurement

  Then, the capacitance Cx of the capacitance type sensor 10 is expressed by the equation (2) from the equation (1). In Formula (2), since values other than the capacitance Cx are known, the capacitance Cx can be calculated.

[Equation 2]
Cx = Vx / {(V−Vf) · Freq · R1} (2)

  As described above, the capacitance Cx of the capacitive sensor 10 can be calculated with a very simple electric circuit, that is, a configuration with a very small number of elements. Accordingly, the capacitance-voltage conversion circuit 22 in the capacitance-type sensor device can be formed very small. Accordingly, the circuit board 20 including the capacitance-voltage conversion circuit 22 can also be reduced in size.

  Here, since the voltage applying element 21 applies the periodic rectangular wave voltage, the frequency Freq and the maximum voltage V of the rectangular wave voltage can be applied with high accuracy as shown in the equation (2). That is, by applying a periodic rectangular wave voltage to the capacitance type sensor 10, the capacitance Cx can be measured with high accuracy. In this way, the capacitance Cx can be measured with high accuracy while being small.

  The capacitive sensor unit 1 is formed as a unit integrated with the capacitive sensor 10, the voltage applying element 21, the capacitive voltage conversion circuit 22, and the wiring unit 30. As described above, since the capacitance-voltage conversion circuit 22 can be reduced in size, even when the entire capacitance-type sensor unit 1 is formed as an integrated unit, the capacitance-type The entire sensor unit 1 can be reduced in size. In particular, by reducing the size of the capacitance / voltage conversion circuit 22 and unitizing the capacitance type sensor unit 1, the length of the wiring portion 30 can be remarkably shortened compared to the conventional case. As a result, the wiring capacity of the wiring unit 30 can be reduced, and noise on the wiring unit 30 can be reduced. Therefore, it is possible to measure the capacitance with high accuracy.

  Further, in the present embodiment, the capacitive sensor 10 is flexible and stretchable. The applications of sensors having such flexible shape properties are very diverse. However, if the capacitance / voltage conversion circuit 22 is large, the circuit board 20 on which the capacitance / voltage conversion circuit 22 is mounted becomes large. Then, when the capacitive sensor unit 1 is unitized, even if the capacitive sensor 10 has a flexible property, the rigidity of the circuit board 20 is relatively conspicuous. However, since the capacitance-type voltage conversion circuit 22 can be miniaturized with the capacitance-type sensor device of the present embodiment, the unit is integrated with the capacitance-type sensor unit 1. However, the rigidity of the circuit board 20 can be made relatively hard to feel. Therefore, the entire capacitive sensor unit 1 of the present embodiment can be recognized as a flexible shape.

<Second embodiment>
The capacitance type sensor device of the second embodiment will be described with reference to FIG. The capacitive sensor device of this embodiment is an example when applied as a wide range of pressure sensitive sensors. Since the capacitive sensor 10 of the first embodiment functions as a single pressure-sensitive sensor, in the second embodiment, the capacitive sensor 10 of the first embodiment is provided at a plurality of locations. . However, since it is not easy to dispose the capacitance-voltage conversion circuit 22 simply by providing a plurality, the configuration as shown in FIG. In addition, in 2nd embodiment, the same code | symbol is attached | subjected about the structure substantially the same as each structure of the electrostatic capacitance type sensor apparatus of 1st embodiment.

  As shown in FIG. 3, the capacitive sensor device of the second embodiment includes a capacitive sensor 110, a power source 100, a voltage applying element 21, and a plurality of capacitive voltage conversion circuits 122a to 122d. The first and second connection switching units 310 and 320, the voltage measuring instrument 200, the switching control unit 330, and the state estimation unit 340 are configured. Further, the voltage application element 21, the first and second connection switching units 310 and 320, the voltage measuring device 200, the switching control unit 330, and the state estimation unit 340 control all or some of these functions. It may be replaced by an equivalent function installed in the unit (microcomputer).

  The capacitive sensor 110 is formed in a rectangular plate shape as a whole. The capacitive sensor 110 includes a plurality of long plate-shaped first electrodes 111 a to 111 d, a plurality of long plate-shaped second electrodes 112 a to 112 d, and a dielectric layer 113. In FIG. 3, the front and back insulating layers are not shown. The first and second electrodes 111a to 111d and 112a to 112d are formed of the same material as the first and second electrodes 11 and 12 of the capacitive sensor 10 of the first embodiment. The plurality of first electrodes 111a to 111d are arranged in parallel with a distance in the surface tangential direction (up and down direction in FIG. 3). The plurality of second electrodes 112a to 112d are arranged in parallel with a distance in the surface tangential direction (left-right direction in FIG. 3), respectively. The direction in which each of the first electrodes 111a to 111d is arranged in parallel (the vertical direction in FIG. 3) is orthogonal to the direction in which each of the second electrodes 112a to 112d is arranged in parallel (the horizontal direction in FIG. 3). Are arranged to be. That is, when viewed from the surface normal direction of the capacitive sensor 110, the first electrodes 111a to 111d and the first electrodes 111a to 111d and the second electrodes 112a to 111d and the second electrodes 112a to 112d form a lattice shape. Two electrodes 112a to 112d are arranged. The dielectric layer 113 is disposed so as to be interposed between the plurality of first electrodes 111a to 111d and the plurality of second electrodes 112a to 112d. The dielectric layer 113 is made of a material that can expand and contract in the normal tangential direction.

  The input side switching circuit 310 includes a plurality of switches 310a to 310d. One end of each of the switches 310a to 310d is configured to be switchable by selecting an output end of the voltage applying element 21 and a ground end to the ground (earth). On the other hand, the other ends of the switches 310a to 310d are connected to the corresponding first electrodes 111a to 111d. That is, the switches 310a to 310d of the input side switching circuit 310 switch between a first state in which the first electrodes 111a to 111d are connected to the voltage application element 21 and a second state in which the first electrodes 111a to 111d are grounded. Then, the switching control unit 330 described later connects one selected from the first electrodes 111a to 111d and the voltage applying element 21 (first state), and grounds the rest of the first electrodes 111a to 111d ( Second state). Although not shown in FIG. 3, the power supply terminal of the voltage application element 21 is connected to the positive side of the power supply 100 as described with reference to FIG. 2, and the ground terminal of the voltage application element 21 is connected to the power supply 100. Connected to the negative terminal.

  The plurality of capacitance voltage conversion circuits 122a to 122d are connected to respective end portions of the corresponding second electrodes 112a to 112d. The capacitance voltage conversion circuits 122a to 122d have the same configuration as the capacitance voltage conversion circuit 22 of the first embodiment. The output side switching circuit 320 includes a plurality of switches 320a to 320d. One end of each of the switches 320a to 320d is connected to the corresponding capacitance voltage conversion circuit 122a to 122d, and the other end of each of the switches 320a to 320d is connected to the voltage measuring instrument 200. Then, the switching control unit 330 connects one selected from the capacitance voltage conversion circuits 122a to 122d and the voltage measuring device 200, and disconnects the rest of the capacitance voltage conversion circuits 122a to 122d.

  The switching control unit 330 performs control to switch ON / OFF operations of the input side switching circuit 310 and the output side switching circuit 320. With reference to FIG. 4, the ON / OFF operation timing chart of the input side switching circuit 310 and the output side switching circuit 320 will be described. After the voltage application element 21 applies the periodic rectangular wave voltage, the first switch 310a of the input side switching circuit 310 is turned ON. Here, ON of the switches 310a to 310d of the input side switching circuit 310 means a state (first state) in which the switches 310a to 310d are connected to the voltage applying element 21 side. At this time, the second, third, and fourth switches 310b, 310c, and 310d of the input side switching circuit 310 are grounded (second state). That is, a periodic rectangular wave voltage is applied only to the first electrode 111a.

  At the same time, the first switch 320a of the output side switching circuit 320 is turned on (connected state). At this time, the second, third, and fourth switches 320b, 320c, and 320d of the output side switching circuit 320 are OFF (disconnected state). In this state, the voltage measuring device 200 measures a voltage corresponding to the capacitance between the first electrode 111a and the second electrode 112a.

  Here, since the first electrodes 111a to 111d are provided in parallel, they may function as a capacitor. That is, there is a possibility of affecting the charge charged / discharged to / from the second electrodes 112a to 112d. However, as described above, in this state, the second, third, and fourth switches 310b, 310c, and 310d of the input side switching circuit 310 are grounded. Therefore, in the above state, when a voltage is applied only to the first electrode 111a, the capacitor does not function between the first electrode 111a and the other first electrodes 111b to 111d. Therefore, the first electrode 111a functions as a capacitor only between the second electrodes 112a to 112d. Therefore, it can prevent that the other 1st electrodes 111b-111d affect the electric charge charged / discharged by the 2nd electrodes 112a-112d. As a result, the voltage measuring device 200 can measure the voltage according to the electrostatic capacitance between the first electrode 111a and the second electrode 112a with high accuracy.

  Subsequently, the first switch 320a of the output side switching circuit 320 is switched OFF, and the second switch 320b is switched ON. Therefore, the voltage measuring device 200 measures a voltage corresponding to the capacitance between the first electrode 111a and the second electrode 112b.

  Thus, while the first switch 310a of the input side switching circuit 310 is on the voltage applying element 21 side (first state), the switches 320a to 320d of the output side switching circuit 320 are sequentially switched ON and OFF. Go. Subsequently, the first switch 310a of the input side switching circuit 310 is switched to ground (second state), and the second switch 310b is switched to the voltage applying element 21 side (first state). In this state, as described above, the switches 320a to 320d of the output side switching circuit 320 are sequentially switched. Then, the switches 310a to 310d of the input side switching circuit 310 are sequentially switched between ON and ground.

  By doing as described above, the voltage measuring instrument 200 obtains a voltage corresponding to the capacitance at each position where the first electrodes 111a to 111d and the second electrodes 112a to 112d intersect in FIG. Can do. Therefore, the state estimation unit 340 can estimate the deformation state of each part of the dielectric layer 113 using these voltages. Based on the estimated deformation state of the dielectric layer 113, the position where the external force is applied and the magnitude of the external force can be estimated. That is, the state estimation unit 340 can calculate the distribution of the surface pressure applied to the capacitive sensor 110.

<First Modification of Second Embodiment>
Here, in the above embodiment, as the dielectric layer 113 is deformed, the capacitance between the electrodes changes as the distance between the first electrodes 111a to 111d and the second electrodes 112a to 112d changes. Then explained. In addition to this aspect, the present invention can be applied to a touch panel that detects a position where a human (operator) touches a finger. In this case, since a human finger functions as a conductor, when the conductor approaches or comes into contact with the capacitive sensor 110, a capacitor is formed between the second electrodes 112a to 112d and the finger. Become. As a result, the capacitances of the first electrodes 111a to 111d and the second electrodes 112a to 112d at positions where the fingers are in contact with or close to each other are different from the capacitances at positions where the fingers are not in contact with or close to each other. That is, the state estimation unit 340 can calculate the approach position, the contact position, or the contact degree of a human finger as a conductor regardless of whether or not the dielectric layer 113 is deformed.

<Second Modification of Second Embodiment>
In the above embodiment, one end of each of the switches 310a to 310d of the input side switching circuit 310 is configured to be able to be switched by selecting the output end of the voltage applying element 21 and the ground end to the ground (earth). It was. Another aspect will be described with reference to FIG. As shown in FIG. 5, one end of each of the switches 311 a to 311 d of the input side switching circuit 311 is configured to be switchable by selecting the output end of the voltage application element 21 and the positive electrode side terminal of the power supply 100. . On the other hand, the other ends of the switches 311a to 311d are connected to the corresponding first electrodes 111a to 111d.

  That is, the positive terminal of the power supply 100 is a terminal to which a constant voltage is applied, and corresponds to high-voltage grounding. In this case, the switching operation of the switches 311a to 311d of the input side switching circuit 311 is the same as the switching operation of the switches 310a to 310d of the input side switching circuit 310 described above. However, ON of the switches 311a to 311d of the input side switching circuit 311 means a state (first state) in which the switches 311a to 311d are connected to the voltage applying element 21 side. Accordingly, in this case as well, the same effects as those of the above embodiment can be obtained.

<Third embodiment>
Next, the capacitive sensor device of the third embodiment will be described with reference to FIGS. As shown in FIGS. 6 and 7, the capacitive sensor 10 of the present embodiment uses a capacitive sensor 10 having substantially the same configuration as that of the first embodiment. However, the shape of the capacitive sensor 10 is long. Further, the output terminal of the voltage application element 21 is connected to one end of the first electrode 11. Furthermore, the first capacitance voltage conversion circuit 222 a is connected to one end of the second electrode 12, and the second capacitance voltage conversion circuit 222 b is connected to the other end of the second electrode 12. Although not shown in FIGS. 6 to 8, the power supply 100 and the voltage measuring device 200 are also provided.

  Then, as shown in FIGS. 6 and 7, a human finger is brought into contact with or close to the surface side of the capacitive sensor 10. Here, the voltage output from the first capacitance-voltage conversion circuit 222a and the voltage output from the second capacitance-voltage conversion circuit 222b differ depending on the position where the finger is in contact with or in proximity. This is due to the influence of the resistance component of the second electrode 12. Therefore, by measuring the voltage output by the first capacitance voltage conversion circuit 222a and the voltage output by the second capacitance voltage conversion circuit 222b, the position where the finger is in contact with or close to the position. Can be calculated.

  Further, consider a case where a human finger is strongly pressed against the capacitive sensor 10 as shown in FIG. In this case, since a human finger functions as a conductor, the state of FIG. 8 can be understood as a change in the area of the capacitor electrode compared to the state of FIG. Therefore, the voltage output by the first capacitance voltage conversion circuit 222a and the voltage output by the second capacitance voltage conversion circuit 222b change according to the force with which the finger is pressed. Therefore, the pressing state by the finger can be estimated based on both voltages.

<Fourth embodiment>
Next, a capacitive sensor device according to a fourth embodiment will be described with reference to FIG. In the third embodiment, the shape of the capacitive sensor 10 is long. The case where the idea of the third embodiment is applied to the rectangular capacitive sensor 10 is the present embodiment. That is, as shown in FIG. 9, the capacitive sensor 10 has a rectangular shape, and the configuration of each layer is the same as that of the first embodiment.

  The output end of the voltage application element 21 is connected to one corner of the first electrode 11. Capacitance-voltage conversion circuits 322a to 322d are connected to the corners of the second electrode 12, respectively. In this case, the voltage output by each of the electrostatic capacitance voltage conversion circuits 322a to 322d varies depending on the position where the finger is in contact with or close to the finger, and further depending on the force with which the finger is pressed. Therefore, by measuring the voltage output from each of the capacitance voltage conversion circuits 322a to 322d, it is possible to estimate the position where the finger is in contact with or close to the finger and the pressing state by the finger.

<Fifth embodiment>
In the above embodiment, the first electrode and the second electrode are provided to face each other in the surface normal direction of the capacitive sensor. In addition, the first electrode and the second electrode can be provided so as to face the surface direction of the capacitive sensor (corresponding to the surface tangential direction if it is a plane). An embodiment in this case will be described with reference to FIGS.

  As shown in FIGS. 10 and 11, the capacitive sensor 410 includes first electrodes 411 a and 411 b, second electrodes 412 a and 412 b, and an insulating layer 413. The insulating layer 413 is made of the same material as the insulating layer 14 of the first embodiment. Although the insulating layer 413 made of the material has flexibility, a material that does not have flexibility can also be used.

  The first electrodes 411a and 411b and the second electrodes 412a and 412b are formed of the same material as the first and second electrodes 11 and 12 of the first embodiment. The first electrodes 411a and 411b and the second electrodes 412a and 412b are arranged in parallel on the back surface side of the insulating layer 413 with a distance in the plane direction of the insulating layer 413 (vertical direction in FIG. 10). The first electrodes 411a and 411b and the second electrodes 412a and 412b are alternately arranged.

  Furthermore, the voltage meter 200 (shown in FIGS. 1 and 2) includes a capacitance between the first electrode 411a and the second electrode 412a, a capacitance between the first electrode 411b and the second electrode 412a, A voltage according to the total amount of capacitance between the first electrode 411b and the second electrode 412b can be measured.

  In this case, when a human finger functioning as a conductor contacts or approaches the insulating layer 413 so as to straddle the first electrode 411a, 411b and the second electrode 412a, 412b, the corresponding finger The first electrode 411a, 411b and the second electrode 412a, 412b function as the other electrode of the capacitor. Therefore, the capacitance between the electrodes changes according to the force with which the finger is pressed as in the third embodiment. Therefore, it is possible to estimate the pressing state with the finger.

<Sixth embodiment>
In the fifth embodiment, the first electrodes 411a and 411b and the second electrodes 412a and 412b are formed in a long shape and arranged in parallel. This embodiment is the case where the idea of the fifth embodiment is applied to the first and second electrodes formed in an annular shape. That is, as shown in FIGS. 12 and 13, the first electrode 511 in the capacitive sensor 510 is formed in an annular shape and disposed on the back side of the insulating layer 513. The second electrode 512 is formed in an annular shape having a smaller diameter than the first electrode 511, and is concentrically disposed on the back surface side of the insulating layer 513 and radially inward of the first electrode 511. The output terminal of the voltage application element 21 is connected to the first electrode 511, and the capacitance-voltage conversion circuit 522 is connected to the second electrode 512. In this case, when a human finger touches or approaches the first electrode 511 and the second electrode 512, the voltage output from the capacitance-voltage conversion circuit 522 changes. Approach can be detected.

<Seventh embodiment>
A capacitive sensor device according to a seventh embodiment will be described with reference to FIGS. 14 and 15. The capacitive sensor 610 has substantially the same configuration as the capacitive sensor 410 in the fifth embodiment (shown in FIG. 10). The voltage application element 21 is connected to one end of the first electrode 611. In addition, the first capacitance voltage conversion circuit 622 a is connected to one end of the second electrode 612, and the second capacitance voltage conversion circuit 622 b is connected to the other end of the second electrode 612.

  In this case, due to the influence of the resistance component of the second electrode 612, as the distance from the position of the second electrode 612 to which the first and second capacitance voltage conversion circuits 622a and 622b are connected as shown in FIG. The output voltage decreases. Using this fact, the position of the finger in the longitudinal direction of the first electrode 611 and the like can be calculated using the difference between the output voltages of the first and second capacitance voltage conversion circuits 622a and 622b.

<Others>
In the present embodiment, the voltage application element 21, the first and second connection switching units 310 and 320, the voltage measuring device 200, the switching control unit 330, and the position calculation unit 340 are all or all of them. Some functions can be replaced by equivalent functions installed in the control unit (microcomputer). In the present embodiment, the capacitive sensor 10 has a flexible and stretchable property. However, when the direction of stretching according to the measurement target is limited or applied to a touch panel or the like, The capacitance type sensor 10 that does not need to have flexibility or stretchability has stretchability for some or all of the materials of the first and second electrodes 11 and 12, the dielectric layer 13, and the insulating layers 14 and 15. It can be replaced with non-use materials such as wood, resin, paper, cloth, etc.

1: Capacitance type sensor unit 2: Capacitance measuring device 10, 110, 410, 510, 610: Capacitance type sensors 11, 111a to 111d, 411a to 411b, 511, 611: First electrode 12, 121a to 121d, 421a to 421b, 521, 621: second electrode 13, 113: dielectric layer 20: circuit board, 21: voltage applying element 22, 122a to 122d, 222a to 222b, 322a to 322d, 422, 522, 622a ˜622b: Capacitance voltage conversion circuit 22a: Rectifier 30: Wiring part 31: First electrode 32: Second electrode 33: Insulating layer 100: Power source 200: Voltage measuring instrument 210: Voltage amplifier 220: Static Capacitance calculation sections 310, 311, 312, 313: input side switching circuits 320, 322, 323, 324: output side switching circuits 33 0: switching control unit, 340: state estimation unit
C1: smoothing capacitor, D1: first diode, D2: second diode R1: shunt resistor for current measurement

Claims (7)

  1. Capacitance having first and second electrodes provided facing each other at a distance, and the capacitance between the first and second electrodes changes with the application of external force or the approach or contact of an operator Type sensors,
    Voltage application means connected in series to the first electrode of the capacitive sensor, and applying a periodic rectangular wave voltage to the capacitive sensor;
    A rectifier that is connected to the second electrode of the capacitive sensor and rectifies the charge that is charged and discharged to the capacitive sensor when the voltage application unit applies the periodic rectangular wave voltage;
    A smoothing capacitor connected in parallel to the rectifier;
    A current measuring shunt resistor connected in parallel to the smoothing capacitor;
    Voltage measuring means for measuring the voltage across the shunt resistor for current measurement;
    A capacitive sensor device comprising :
    The capacitive sensor is
    It is a capacitive sensor formed in a surface shape,
    The first and second electrodes provided facing each other at a distance in the surface normal direction of the capacitive sensor; the dielectric layer provided between the first and second electrodes; An insulating layer provided on the surface side of the capacitive sensor,
    According to the approach or contact state of the operator as a conductor to the surface of the capacitance type sensor, the capacitance between the first and second electrodes changes,
    The rectifier, the smoothing capacitor, and the current measurement shunt resistor are composed of a plurality connected to a plurality of locations of the second electrode, respectively.
    The plurality of rectifiers are connected to different positions of the second electrode,
    The electrostatic capacitance type sensor device is configured to detect the electrostatic capacity based on the both-end voltages of the current measuring shunt resistors measured by the voltage measuring unit when the rectangular wave voltage is applied by the voltage applying unit. A capacitive sensor device further comprising state estimation means for estimating at least one of an approach position, a contact position, and a contact state of an operator approaching or contacting the capacitive sensor.
  2. Capacitance having first and second electrodes provided facing each other at a distance, and the capacitance between the first and second electrodes changes with the application of external force or the approach or contact of an operator Type sensors,
    Voltage application means connected in series to the first electrode of the capacitive sensor, and applying a periodic rectangular wave voltage to the capacitive sensor;
    A rectifier that is connected to the second electrode of the capacitive sensor and rectifies the charge that is charged and discharged to the capacitive sensor when the voltage application unit applies the periodic rectangular wave voltage;
    A smoothing capacitor connected in parallel to the rectifier;
    A current measuring shunt resistor connected in parallel to the smoothing capacitor;
    Voltage measuring means for measuring the voltage across the shunt resistor for current measurement;
    A capacitive sensor device comprising :
    The capacitive sensor is
    It is a capacitive sensor formed in a surface shape,
    The first and second electrodes provided at a distance in the surface direction of the capacitive sensor, and an insulating layer provided on the surface side of the capacitive sensor,
    According to the approach or contact state of the operator as a conductor to the surface of the capacitance type sensor, the capacitance between the first and second electrodes changes,
    The rectifier, the smoothing capacitor, and the current measurement shunt resistor are composed of a plurality connected to a plurality of locations of the second electrode, respectively.
    The plurality of rectifiers are connected to different positions of the second electrode,
    The electrostatic capacitance type sensor device is configured to detect the electrostatic capacity based on the both-end voltages of the current measuring shunt resistors measured by the voltage measuring unit when the rectangular wave voltage is applied by the voltage applying unit. A capacitive sensor device further comprising state estimation means for estimating at least one of an approach position, a contact position, and a contact state of an operator approaching or contacting the capacitive sensor.
  3. In claim 1 or 2 ,
    The voltage measuring means is based on the charging voltage of the capacitive sensor, the frequency of the rectangular wave voltage applied by the voltage applying means, and the resistance value of the current measuring shunt resistor. A capacitance type sensor device that measures a voltage across a resistor as a capacitance of the capacitance type sensor.
  4. In any one of Claims 1-3 ,
    The capacitive sensor device, wherein the capacitive sensor, the voltage applying means, the rectifier, the smoothing capacitor, and the current measuring shunt resistor are formed as an integral unit.
  5. In claim 4 ,
    The first and second electrodes of the capacitive sensor are electrodes having flexibility and elastic properties,
    The capacitance type sensor device is a capacitance type sensor device having flexibility and elastic properties.
  6. Capacitance having first and second electrodes provided facing each other at a distance, and the capacitance between the first and second electrodes changes with the application of external force or the approach or contact of an operator A measuring device for measuring the capacitance of the mold sensor,
    Voltage application means connected in series to the first electrode of the capacitive sensor, and applying a periodic rectangular wave voltage to the capacitive sensor;
    A rectifier that is connected to the second electrode of the capacitive sensor and rectifies the charge that is charged and discharged to the capacitive sensor when the voltage application unit applies the periodic rectangular wave voltage;
    A smoothing capacitor connected in parallel to the rectifier;
    A current measuring shunt resistor connected in parallel to the smoothing capacitor;
    Voltage measuring means for measuring the voltage across the shunt resistor for current measurement;
    Equipped with a,
    The capacitive sensor is
    It is a capacitive sensor formed in a surface shape,
    The first and second electrodes provided facing each other at a distance in the surface normal direction of the capacitive sensor; the dielectric layer provided between the first and second electrodes; An insulating layer provided on the surface side of the capacitive sensor,
    According to the approach or contact state of the operator as a conductor to the surface of the capacitance type sensor, the capacitance between the first and second electrodes changes,
    The rectifier, the smoothing capacitor, and the current measurement shunt resistor are composed of a plurality connected to a plurality of locations of the second electrode, respectively.
    The plurality of rectifiers are connected to different positions of the second electrode,
    The capacitance-type measuring device is configured to detect the electrostatic capacitance based on the both-end voltages of the current measuring shunt resistors measured by the voltage measuring unit when the rectangular wave voltage is applied by the voltage applying unit. A capacitance-type measuring device further comprising state estimation means for estimating at least one of an approach position, a contact position, and a contact state of an operator approaching or contacting the capacitive sensor.
  7. Capacitance having first and second electrodes provided facing each other at a distance, and the capacitance between the first and second electrodes changes with the application of external force or the approach or contact of an operator A measuring device for measuring the capacitance of the mold sensor,
    Voltage application means connected in series to the first electrode of the capacitive sensor, and applying a periodic rectangular wave voltage to the capacitive sensor;
    A rectifier that is connected to the second electrode of the capacitive sensor and rectifies the charge that is charged and discharged to the capacitive sensor when the voltage application unit applies the periodic rectangular wave voltage;
    A smoothing capacitor connected in parallel to the rectifier;
    A current measuring shunt resistor connected in parallel to the smoothing capacitor;
    Voltage measuring means for measuring the voltage across the shunt resistor for current measurement;
    Equipped with a,
    The capacitive sensor is
    It is a capacitive sensor formed in a surface shape,
    The first and second electrodes provided at a distance in the surface direction of the capacitive sensor, and an insulating layer provided on the surface side of the capacitive sensor,
    According to the approach or contact state of the operator as a conductor to the surface of the capacitance type sensor, the capacitance between the first and second electrodes changes,
    The rectifier, the smoothing capacitor, and the current measurement shunt resistor are composed of a plurality connected to a plurality of locations of the second electrode, respectively.
    The plurality of rectifiers are connected to different positions of the second electrode,
    The capacitance-type measuring device is configured to detect the electrostatic capacitance based on the both-end voltages of the current measuring shunt resistors measured by the voltage measuring unit when the rectangular wave voltage is applied by the voltage applying unit. A capacitance-type measuring device further comprising state estimation means for estimating at least one of an approach position, a contact position, and a contact state of an operator approaching or contacting the capacitive sensor.
JP2012509510A 2010-03-31 2011-03-30 Capacitance type sensor device and capacitance measuring device for capacitance type sensor Active JP5326042B2 (en)

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