JP2013205370A - Capacitance-type sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a capacitance-type sensor having high degree of freedom in shape setting.SOLUTION: A capacitance-type sensor 1 comprises a base material 20 made of resin or an elastomer, and a pair of electrodes 21 that includes an elastomer and a conductive material and are arranged separated from each other on one surface of the base material 20. The capacitance-type sensor 1 detects a detection amount that is at least one of a level L and material of fluid G on the basis of a change in capacitance between the pair of electrodes 21. Both of the pair of electrodes 21 of the capacitance-type sensor 1 have high flexibility to provide high degree of freedom in shape setting.

Description

  The present invention relates to a capacitance type sensor used for detecting, for example, the level of gasoline stored in a fuel tank.

  Patent Document 1 discloses a capacitive water level sensor. The water level sensor includes a base material and a pair of electrodes. The pair of electrodes are stacked on the base material with a predetermined distance therebetween. The base material is made of an insulating resin. The pair of electrodes are wiring leads. Patent Document 2 discloses a capacitance type liquid level liquid quality sensor. The liquid level liquid quality sensor includes a base material and a pair of electrodes. The pair of electrodes are stacked on the base material with a predetermined distance therebetween. The substrate is made of polyimide. The pair of electrodes is made of a resin paste containing carbon. Patent Documents 3 and 4 disclose a capacitance type level sensor capable of detecting the level of liquid or granular material.

Japanese Patent Laid-Open No. 11-223545 JP-A-2005-351688 Japanese Patent Laid-Open No. 11-83595 JP 2004-144613 A

  Of Patent Documents 1 to 4, the materials of the electrodes are disclosed in Patent Document 1 (lead wire for wiring) and Patent Document 2 (resin paste containing carbon). The materials disclosed in these documents are all hard and have low flexibility. For this reason, the conventional capacitive sensor has a low degree of freedom in setting the shape.

  The capacitive sensor of the present invention has been completed in view of the above problems. An object of the present invention is to provide a capacitance type sensor having a high degree of freedom in shape setting.

  (1) In order to solve the above-described problem, a capacitive sensor of the present invention includes a base material made of a resin or an elastomer, an elastomer and a conductive material, and is a pair that is spaced apart from each other on one surface of the base material. And detecting a detection amount which is at least one of the level and the material of the fluid based on the change in capacitance between the pair of electrodes.

  Here, the “fluid” includes liquids, fluid solids (powder, granules, etc.), and gels. According to the capacitive sensor of the present invention, the flexibility of the electrode is high. For this reason, the freedom of shape setting is high. Further, even if the electrode is deformed (expanded, curved, etc.), it is difficult for the electrode to crack. For this reason, even if the capacitive sensor is deformed, the change in the conductivity of the electrode is small.

  (2) Preferably, in the configuration of (1) above, it is better to have a configuration including a plurality of detection sections with different detection sensitivities. According to this configuration, a difference in detection sensitivity can be set for a single capacitive sensor.

  (3) Preferably, in the configuration of (2), the detection amount is the level of the fluid, and the plurality of detection sections may have different inclination angles with respect to the horizontal direction.

  Here, “level” means the liquid level when the fluid is liquid. In the case of powder, it means powder level. When a plurality of fluids are mixed, the “level” includes an interface between adjacent fluids (for example, an interface between water and oil).

  The capacitive sensor of this configuration is flexible. For this reason, it is possible to easily set a plurality of detection sections in the capacitive sensor. In other words, the capacitive sensor can be easily bent.

  In the detection section with a steep inclination (detection section with a large inclination angle), the change in capacitance with respect to the level change is small. For this reason, detection sensitivity is low. On the other hand, in the detection section where the inclination is gentle (the detection section where the inclination angle is small), the change in capacitance with respect to the level change is large. For this reason, the detection sensitivity is high. According to this configuration, it is possible to easily set a detection sensitivity difference in a single capacitive sensor by bending the capacitive sensor.

  (4) Preferably, in the configuration of (2), the detection amount is the level of the fluid, and the plurality of detection sections are configured such that the distance between the pair of electrodes is different from each other. Good.

According to the capacitive sensor of this configuration, the level of the fluid can be detected. Here, the distance between the electrodes is d, the electrode area is S, the vacuum dielectric constant is ε0, the first layer (if the fluids are adjacent to each other, the first fluid (liquid, powder, etc.), When the gas is adjacent, the dielectric constant of the gas (such as air) is εr1, the second layer (when the fluids are adjacent to each other, the second fluid, and when the fluid and the gas are adjacent, the fluid is flowing The capacitance C is derived from the following equation (1), where εr2 is the relative dielectric constant of the body, and x is the height ratio of the second layer with respect to the interelectrode distance d.
C = ε0 · {(1-x) · εr1 + x · εr2} · S / d Formula (1)
As can be seen from Equation (1), the capacitance C increases as the inter-electrode distance d decreases. For this reason, detection sensitivity can be made high. In this regard, the inter-electrode distance d is different between the plurality of detection sections of the capacitive sensor of this configuration. In the detection section where the interelectrode distance d is long, the capacitance is small. For this reason, detection sensitivity is low. On the other hand, the capacitance is large in the detection section where the inter-electrode distance d is short. For this reason, the detection sensitivity is high. According to this configuration, by adjusting the inter-electrode distance d, it is possible to easily set a detection sensitivity difference in a single capacitive sensor.

  (4-1) Preferably, in the configuration of (4), the tank in which the fluid is accommodated includes a plurality of inclined sections having different inclination angles with respect to the horizontal direction, and the inclined section having the smallest inclination angle. It is better to make the detection section with the longest distance between the pair of electrodes correspond to the detection section with the longest inclination angle and the detection section with the shortest distance between the pair of electrodes. .

  The detection sensitivity increases as the inclination angle of the inclination section decreases. In this regard, according to the present configuration, the detection section with the longest inter-electrode distance is associated with the inclination section with the minimum inclination angle. In addition, the detection interval with the shortest distance between the electrodes is associated with the inclination interval with the maximum inclination angle. For this reason, variation in detection sensitivity due to the magnitude of the tilt angle can be suppressed.

  (5) Preferably, in the configuration according to any one of (1) to (4), the detection amount is the level of the fluid, and the pair of electrodes are combs extending in a vertical direction, respectively. It is better to have a configuration in which teeth have teeth and the comb teeth of the pair of electrodes are alternately arranged in the horizontal direction. According to the capacitive sensor of this configuration, the level of the fluid can be detected. Moreover, the electrode area S in Formula (1) can be widened. For this reason, detection sensitivity can be made high.

  (6) Preferably, in any one of the configurations (1) to (4), the detection amount is the level of the fluid, and the pair of electrodes are combs extending in a horizontal direction, respectively. It is better to have a structure in which the comb teeth of the pair of electrodes are alternately arranged in the vertical direction. According to the capacitive sensor of this configuration, the level of the fluid can be detected. In addition, it is possible to easily set a detection sensitivity difference for a single capacitance type sensor.

  (7) Preferably, in any one of the configurations (1) to (6), it is better to have a configuration in which at least one of the outer peripheral surface and the inner peripheral surface of the pipe through which the fluid flows is arranged. .

  According to this configuration, the detection amount of the fluid in the pipe can be detected. Further, the capacitive sensor of this configuration is flexible. For this reason, an electrostatic capacitance type sensor can be easily arrange | positioned to piping irrespective of the curvature of piping.

  (8) Preferably, in any one of the configurations (1) to (7), the fluid is a fuel for a transport machine, and the detected amount is a fuel type that is the material of the fuel, It is better to provide a control device that transmits the fuel type to the transport machine. According to this configuration, the fuel type is transmitted from the capacitive sensor to the transport machine. For this reason, the transport machine can recognize the fuel type.

  (9) Preferably, in the configuration of any one of the above (1) to (8), the electrode is formed from a paint including the elastomer and the conductive material. The coating material may contain additives such as a dispersant, a reinforcing agent, a plasticizer, an anti-aging agent, and a colorant as required in addition to the elastomer and the conductive material. The paint is prepared by dispersing a conductive material in a solution in which a polymer of an elastomer component (a polymer before crosslinking when the elastomer is a crosslinked rubber) is dissolved in a solvent together with a predetermined additive. And the prepared coating material is apply | coated to a base material etc., it is made to dry and an electrode is formed. What is necessary is just to advance a crosslinking reaction at the time of drying as needed. What is necessary is just to adjust the solid content density | concentration of a coating material suitably so that it may become a viscosity suitable for the apply | coating method to employ | adopt. For example, when the solid content concentration of the paint is increased, swelling of the substrate or the like by the solvent when applied can be suppressed. According to this configuration, the thin film electrode can be easily formed.

  Various known methods can be employed as a method for applying the paint. For example, in addition to printing methods such as screen printing, inkjet printing, flexographic printing, gravure printing, pad printing, and lithography, dipping, spraying, bar coating, and the like can be given. For example, when a printing method is employed, it is possible to easily separate the applied part and the non-applied part. Also, printing of large areas, thin lines, and complicated shapes is easy. Among the printing methods, a screen printing method is preferable because a highly viscous paint can be used and the coating thickness can be easily adjusted.

  (10) Preferably, in any one of the configurations (1) to (9), the conductive material may include metal particles. In general, the volume resistivity of metals is small. Therefore, according to this configuration, the volume resistivity of the electrode can be reduced. In other words, the conductivity of the electrode can be increased. Examples of the metal particles include silver, copper, gold, nickel, rhodium, palladium, chromium, titanium, platinum, iron, and alloys thereof. One of these may be used alone, or two or more may be mixed and used. Of these, silver and copper are suitable because of their low volume resistivity. Therefore, it is preferable to use silver powder, copper powder, silver alloy powder, or copper alloy powder as the conductive material.

  (11) Preferably, in the configuration of any one of the above (1) to (10), the elongation at the time of cutting of the base material is 5% or more. The substrate is made of resin or elastomer. According to this structure, the elasticity of the base material at room temperature can be ensured. In addition, in this specification, the value calculated | required by the tension test of JISK6251 (2010) is employ | adopted as elongation at the time of a cutting | disconnection.

  (11-1) Preferably, in the configuration of (11), the resin of the base material is a polyester resin, a modified polyester resin (such as a urethane-modified polyester resin, an epoxy-modified polyester resin, or an acrylic-modified polyester resin), a polyether. Urethane resin, polycarbonate urethane resin, vinyl chloride-vinyl acetate copolymer, phenol resin, acrylic resin, polyamideimide resin, polyamide resin, nitrocellulose, modified celluloses (cellulose, acetate, butyrate (CAB), cellulose acetate, propionate (CAP) etc.) and the like, it is better to have a configuration that is at least one selected from thermosetting resins and thermoplastic resins. Further, the elastomer of the base material is silicone rubber, ethylene-propylene copolymer rubber, natural rubber, styrene-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber, acrylic rubber, epichlorohydrin rubber, chlorosulfonated polyethylene, One or more types selected from cross-linked rubbers such as chlorinated polyethylene, urethane rubber, fluoro rubber, chloroprene rubber, isobutylene isoprene rubber, and thermoplastic elastomers such as styrene, olefin, vinyl chloride, polyester, polyurethane, and polyamide. It is better to have a configuration.

  (12) Preferably, in any one of the constitutions (1) to (11), the base material and the elastomer of the pair of electrodes are crosslinked without using sulfur, a sulfur compound, or an organic peroxide. It is better to have a constitution that is at least one selected from a crosslinked rubber and a thermoplastic elastomer.

  When a rubber polymer is crosslinked, sulfur, a sulfur compound, or an organic peroxide is often used as a crosslinking agent. If these crosslinking agent residues remain in the crosslinked rubber, the metal particles may be oxidized or sulfided when the electrode contains metal particles as a conductive material. When the metal particles are oxidized and sulfided, the electrical resistance on the surface of the metal particles increases, and the conductivity of the electrode decreases.

  In this regard, according to the present configuration, the base material and the electrode elastomer do not contain sulfur, a sulfur compound, or an organic peroxide. For this reason, even if metal particles are included as a conductive material, the metal particles are unlikely to deteriorate due to oxidation or sulfuration. Therefore, even when used for a long period of time, the conductivity of the electrode is unlikely to decrease. That is, according to this configuration, the durability of the capacitive sensor is improved.

  (13) Preferably, in any one of the configurations (1) to (12), an elastomer cover layer is provided so as to cover the pair of electrodes.

  According to this configuration, the electrode can be insulated from the outside. For this reason, safety is improved. Moreover, when the electrode contains metal particles as a conductive material, oxidation of the metal particles can be suppressed. The electrode is sandwiched between the base material and the cover layer. For this reason, the deformation of the electrode is regulated by the base material and the cover layer. Therefore, the electrode can be reinforced and protected.

  The elastomer of the cover layer may be the same as or different from the elastomer of the base material. Further, from the viewpoint of not inhibiting the expansion and contraction of the base material and the electrode, it is desirable that the elongation at break of the cover layer is 5% or more.

  (14) Preferably, in the configuration of (13), the elastomer of the cover layer is one or more selected from sulfur, a sulfur compound, a crosslinked rubber crosslinked without using an organic peroxide, and a thermoplastic elastomer. It is better to have a configuration of

  As described in (12) above, if the crosslinking agent residue remains in the cover layer, the metal particles contained in the electrode may be oxidized or sulfided. According to this configuration, even if the electrode includes metal particles as a conductive material, the metal particles are unlikely to deteriorate due to oxidation or sulfuration. Therefore, even when used for a long period of time, the conductivity of the electrode is unlikely to decrease. That is, according to this configuration, the durability of the capacitive sensor is improved.

  According to the present invention, it is possible to provide a capacitive sensor having a high degree of freedom in shape setting.

It is a front view of the capacitance type sensor of a first embodiment. It is the II-II direction sectional drawing of FIG. (A) is an up-down direction sectional view of the fuel tank of the car in which the same capacitive sensor is arranged. (B) is a schematic graph which shows the responsiveness of the voltage with respect to the change of a liquid level. It is a front view of the capacitive type sensor of 2nd embodiment. (A) is an up-down direction sectional view of the fuel tank of the car in which the same capacitive sensor is arranged. (B) is a schematic graph which shows the responsiveness of the voltage with respect to the change of a liquid level. (A) is an up-down direction sectional view of the fuel tank of the car in which the capacitive sensor of the third embodiment is arranged. (B) is a schematic graph which shows the responsiveness of the voltage with respect to the change of a liquid level. (A) is an up-down direction sectional view of a fuel tank of an automobile in which a capacitive sensor according to a fourth embodiment is arranged. (B) is a schematic graph which shows the responsiveness of the voltage with respect to the change of a liquid level. It is a front view of the capacitive type sensor of 5th embodiment. It is a front view of the capacitive type sensor of 6th embodiment. It is a front view of piping by which the capacitive sensor of 7th embodiment is arrange | positioned. It is a block diagram of the electrostatic capacitance type sensor of 8th embodiment, and the control apparatus of a motor vehicle. It is a front view of the capacitive sensor of the ninth embodiment.

  Hereinafter, embodiments of the capacitive sensor of the present invention will be described.

<First embodiment>
[Configuration of capacitive sensor]
First, the configuration of the capacitive sensor of this embodiment will be described. FIG. 1 is a front view of the capacitive sensor according to the present embodiment. FIG. 2 shows a cross-sectional view in the II-II direction of FIG. In FIG. 1, the cover layer is omitted. As shown in FIGS. 1 and 2, the capacitive sensor 1 of this embodiment includes a base material 20, a pair of electrodes 21, a cover layer 22, and a control device 23.

  The base material 20 is made of silicone rubber (elastomer) and has a rectangular sheet shape extending in the vertical direction. The base material 20 has insulating properties. The elongation at the time of cutting of the base material 20 is 400%.

  Each of the pair of electrodes 21 includes amine-crosslinked acrylic rubber (elastomer) and silver particles (metal particles). The content of silver particles is 38 vol% when the volume of the electrode 21 is 100 vol%. Each of the pair of electrodes 21 has a rectangular shape extending in the vertical direction. Each of the pair of electrodes 21 has conductivity. The pair of electrodes 21 are both disposed on the front surface of the base material 20. The pair of electrodes 21 are spaced apart in the left-right direction. The distance between the pair of electrodes 21 is constant over the entire length in the vertical direction.

  The cover layer 22 is made of silicone rubber (elastomer) and has a rectangular film shape extending in the vertical direction. The cover layer 22 has an insulating property. The cover layer 22 is laminated on the front surface of the base material 20 through the pair of electrodes 21. The cover layer 22 protects the pair of electrodes 21 from the external environment.

  The control device 23 includes a C / V conversion unit 230, a calculation unit 231, and a storage unit 232. The C / V conversion unit 230 converts the capacitance transmitted from the pair of electrodes 21 into a voltage. The storage unit 232 stores a correlation table between a voltage and a liquid level (level) of gasoline (fuel) described later.

[Method of manufacturing capacitive sensor]
Next, a method for manufacturing the capacitive sensor 1 of the present embodiment will be described. First, a silicone rubber sheet is prepared as the base material 20. Next, a pair of electrodes 21 is formed. That is, an acrylic rubber polymer and a crosslinking agent ammonium benzoate are dissolved in a solvent ethylene glycol monobutyl ether acetate to prepare a polymer solution. And a silver powder is mixed and disperse | distributed to a polymer solution, and a coating material is prepared. Subsequently, the prepared paint is screen-printed on the front surface of the substrate 20. Then, while drying a coating film by heating, a crosslinking reaction is advanced. In this way, a pair of electrodes 21 is formed.

  Subsequently, the cover layer 22 is formed. A liquid silicone rubber polymer is screen-printed on the front surface of the substrate 20 so as to cover the pair of electrodes 21. And a crosslinking reaction is advanced by heating a coating film. In this way, the cover layer 22 is formed. Then, the pair of electrodes 21 and the control device 23 are electrically connected. In this way, the capacitive sensor 1 is manufactured.

[Capacitance type sensor arrangement]
Next, the arrangement of the capacitive sensor 1 of this embodiment will be described. FIG. 3A shows a vertical sectional view of a fuel tank of an automobile in which the capacitive sensor of this embodiment is arranged. FIG. 3B is a schematic graph showing the voltage responsiveness to the change in the liquid level. Note that the capacitive sensor 1 shown in FIG. 3A corresponds to the sectional view in the III-III direction of FIG.

  As shown in FIG. 3A, gasoline G is stored in a fuel tank 90 of an automobile (transport machine). The liquid level L of the gasoline G is lowered by operation and is raised by refueling. In the fuel tank 90, the capacitive sensor 1 curved in an L shape protruding rearward is disposed along the side surface 900 and the bottom surface 901. The capacitive sensor 1 detects the liquid level L.

  The capacitive sensor 1 includes three detection sections A1 to A3 from the bottom to the top. When the inclination angle θ1 of the detection section A1 with respect to the front-rear direction (horizontal direction), the inclination angle θ2 of the tangent of the center A2a of the detection section A2 and the inclination angle θ3 of the detection section A3 are compared, θ1 <θ2 <θ3 The relationship is established. That is, the detection sections A <b> 1 to A <b> 3 are arranged so that the inclination becomes gentler as the bottom surface 901 of the fuel tank 90 is closer.

  When the liquid level L changes, the amount of gasoline G (second layer related to the relative dielectric constant εr2 of the formula (1)) interposed between the pair of electrodes 21 shown in FIG. For this reason, the height ratio x (the liquid level ratio x of gasoline G) in the equation (1) changes. Accordingly, the capacitance C in the equation (1) changes. When the capacitance C changes, the voltage input to the calculation unit 231 shown in FIG. 1 changes. The calculation unit 231 queries the correlation table of the storage unit 232 for the voltage. And the liquid level L of the gasoline G is detected.

  As shown in FIG. 3B, in the detection section A1 having a small inclination angle θ1, the amount of gasoline G interposed between the pair of electrodes 21 with respect to the change in the liquid level L increases. For this reason, the responsiveness of the voltage with respect to the change of the liquid level L increases. Therefore, the detection sensitivity of the liquid level L is increased. In contrast, in the detection section A3 having a large inclination angle θ3 (approximately 90 °), the increase or decrease in the amount of gasoline G interposed between the pair of electrodes 21 with respect to the change in the liquid level L is small. For this reason, the voltage responsiveness to the change in the liquid level L is lowered. Therefore, the detection sensitivity of the liquid level L is lowered. Further, in the detection section A2 having a medium inclination angle θ2, the voltage responsiveness to the change in the liquid level L is also medium. Therefore, the detection sensitivity of the liquid level L is also medium.

[Function and effect]
Next, the function and effect of the capacitive sensor 1 of the present embodiment will be described. According to the capacitive sensor 1 of the present embodiment, as shown in FIG. 1, the pair of electrodes 21 are arranged on the front surface of the base material 20, that is, on the same surface. For this reason, compared with the case where a pair of electrode 21 is arrange | positioned facing a horizontal direction via gasoline G, the liquid level L of gasoline G does not rise easily by a capillary phenomenon. Therefore, the detection error of the liquid level L accompanying the capillary phenomenon is small.

  The electrode 21 includes amine-crosslinked acrylic rubber (elastomer) and silver particles (metal particles). For this reason, the electrode 21 is highly flexible. Therefore, the degree of freedom in setting the shape of the pair of electrodes 21 and thus the capacitance type sensor 1 is high. Therefore, as shown in FIG. 3A, the capacitance type sensor 1 can be easily curved and arranged in an L shape.

  In addition, since the electrode 21 is highly flexible, cracks are unlikely to occur in the electrode 21 even if the capacitive sensor 1 is curvedly arranged in an L shape (even if the electrode 21 is curved). Therefore, even if the capacitive sensor 1 is curved and arranged in an L shape, the change in conductivity of the electrode 21 is small.

  Further, the capacitive sensor 1 of the present embodiment is flexible. For this reason, as shown to Fig.3 (a), three detection area A1-A3 from which inclination-angle (theta) 1-theta3 mutually differs can be set easily.

  In the detection section A3 where the inclination angle θ3 is large, the change in capacitance with respect to the change in the liquid level L is small. For this reason, detection sensitivity is low. On the other hand, in the detection section A1 where the inclination angle θ1 is small, the change in capacitance with respect to the change in the liquid level L is large. For this reason, the detection sensitivity is high. Thus, by curving the capacitive sensor 1, three detection sections A1 to A3 having different detection sensitivities can be easily set.

  Further, in the fuel tank 90 of the automobile, the detection of the liquid level L is required more accurately when the gasoline G is near empty than when the gasoline G is almost full. Assuming that the capacitive sensor 1 is arranged in a straight line as shown by a dotted line in FIG. In this case, as indicated by a dotted line in FIG. 3B, the slope of the correlation line (= liquid level change / voltage change) is constant. That is, the voltage responsiveness to changes in the liquid level L is constant. Therefore, the detection sensitivity is constant regardless of the remaining amount of gasoline G in the fuel tank 90 (regardless of the level of the liquid level L).

  In this regard, according to the capacitive sensor 1 of the present embodiment, the detection sections A1 to A3 are arranged so that the inclination becomes gentler as the bottom surface 901 of the fuel tank 90 is closer. That is, the detection sections A <b> 1 to A <b> 3 are arranged so that the detection sensitivity increases as the distance from the bottom surface 901 of the fuel tank 90 is closer. For this reason, the liquid level L can be detected more accurately in a state where the gasoline G is nearly empty.

  Moreover, according to the capacitive sensor 1 of the present embodiment, the electrode 21 is formed from a paint containing amine-crosslinked acrylic rubber (elastomer) and silver particles (metal particles). For this reason, the electrode 21 can be easily formed and arranged by printing the paint on the base material 20 using a screen printer. Further, the thickness in the front-rear direction of the electrode 21 can be easily and accurately made by the thickness of the screen mask, and the shape of the electrode in the surface direction can be made by the hole shape of the screen mask. The electrode 21 contains silver particles. For this reason, the volume resistivity of the electrode 21 can be reduced. In other words, the conductivity of the electrode 21 can be increased.

  Moreover, the base material 20 of the capacitive sensor 1 of the present embodiment is made of silicone rubber. Moreover, the elongation at the time of cutting of the base material 20 is 400%. For this reason, the base material 20 has high stretchability in the surface direction. Also in this point, the capacitive sensor 1 is flexible.

  In addition, the capacitive sensor 1 of this embodiment includes a cover layer 22 made of silicone rubber (the same material as the base material 20). For this reason, the electrode 21 can be protected from the gasoline G. Moreover, the electrode 21 can be insulated. Further, an increase in the liquid level L of the gasoline G due to the current state of the capillary tube can be suppressed. For this reason, the detection error of the liquid level L accompanying a capillary phenomenon is small. Moreover, the oxidation of the silver particles in the electrode 21 can be suppressed. Further, the deformation of the electrode 21 is regulated by the base material 20 and the cover layer 22. Therefore, the electrode 21 can be reinforced and protected.

<Second embodiment>
The difference between the capacitance type sensor of this embodiment and the capacitance type sensor of the first embodiment is that detection intervals having different inter-electrode distances are set in the capacitance type sensor. is there. Here, only differences will be described.

  FIG. 4 shows a front view of the capacitive sensor of the present embodiment. In addition, about the site | part corresponding to FIG. 1, it shows with the same code | symbol. As shown in FIG. 4, the capacitive sensor 1 of the present embodiment includes three detection sections A4 to A6 from the bottom to the top. When the inter-electrode distance d4 in the detection section A4, the inter-electrode distance d5 in the detection section A5, and the inter-electrode distance d6 in the detection section A6 are compared, the relationship d6 <d4 <d5 is established. From equation (1), the capacitance C increases as the inter-electrode distance d decreases. For this reason, detection sensitivity can be made high.

  FIG. 5A shows a vertical sectional view of a fuel tank of an automobile in which the capacitive sensor of this embodiment is arranged. FIG. 5B is a schematic graph showing the voltage responsiveness to the change in the liquid level. The capacitive sensor 1 shown in FIG. 5A corresponds to the cross-sectional view in the VV direction of FIG. Moreover, about the site | part corresponding to Fig.3 (a) and FIG.3 (b), it shows with the same code | symbol.

  As shown in FIG. 5A, three inclined sections 900 a to 900 c are arranged on the side surface 900 of the fuel tank 90 from the bottom to the top. When the inclination angle α1 of the inclined section 900a, the inclination angle α2 of the inclined section 900b, and the inclination angle α3 of the inclined section 900c with respect to the front-rear direction (horizontal direction) are compared, the relationship of α2 <α1 <α3 is established. Yes.

  A detection section A5 having a long inter-electrode distance d5 is arranged in the inclination section 900b having a small inclination angle α2. That is, in the inclined section 900b having the small inclination angle α2, the increase / decrease in the amount of gasoline G interposed between the pair of electrodes 21 with respect to the change in the liquid level L increases. For this reason, as shown by a dotted line in FIG. 5B, when a capacitance type sensor (see FIG. 1) having a constant inter-electrode distance over the entire length in the vertical direction is used, the voltage response to the change in the liquid level L. It will be high. Therefore, the detection section A5 having a low detection sensitivity is assigned to the inclined section 900b where the voltage responsiveness tends to be high. For this reason, it can suppress that the detection sensitivity in the inclination area 900b becomes high too much.

  On the other hand, a detection section A6 having a short inter-electrode distance d6 is arranged in the inclination section 900c having a large inclination angle α3 (approximately 90 °). That is, in the inclined section 900c having a large inclination angle α3, the increase or decrease in the amount of gasoline G interposed between the pair of electrodes 21 with respect to the change in the liquid level L is small. For this reason, as shown by a dotted line in FIG. 5B, when a capacitance type sensor (see FIG. 1) having a constant inter-electrode distance over the entire length in the vertical direction is used, the voltage response to the change in the liquid level L. It becomes low. Therefore, the detection section A6 with high detection sensitivity is assigned to the inclined section 900c where the voltage responsiveness tends to be low. For this reason, it can suppress that the detection sensitivity in the inclination area 900c becomes low too much. In addition, a detection section A4 having a medium detection sensitivity is assigned to the inclination section 900a having a medium inclination angle α1.

  The capacitive sensor 1 according to this embodiment and the capacitive sensor according to the first embodiment have the same functions and effects with respect to parts having the same configuration. Further, according to the capacitive sensor 1 of the present embodiment, as shown in FIG. 5A, three detection sections A4 to A6 having different inter-electrode distances d4 to d6 are set. For this reason, as shown in FIG. 5 (b), the difference between the inclination angles α1 to α3 is shown in spite of the fact that three inclination sections 900a to 900c having different inclination angles α1 to α3 are arranged in the fuel tank 90. The difference between the electrode distances d4 to d6 can be offset. That is, the detection sensitivity in the three inclined sections 900a to 900c can be made uniform.

<Third embodiment>
The difference between the capacitive sensor of the present embodiment and the capacitive sensor of the first embodiment is that the pair of electrodes each have comb teeth extending in the vertical direction. It is. Here, only differences will be described.

  FIG. 6A shows a vertical sectional view of a fuel tank of an automobile in which the capacitive sensor of this embodiment is arranged. FIG. 6B is a schematic graph showing the voltage responsiveness to the change in the liquid level. In addition, about the site | part corresponding to Fig.3 (a) and FIG.3 (b), it shows with the same code | symbol. For convenience of explanation, one electrode 21 is hatched. Further, the cover layer is omitted.

  As shown in FIG. 6A, the electrode 21 includes a plurality of comb teeth portions 210. The comb-tooth part 210 has a narrow strip shape extending in the vertical direction. The plurality of comb-tooth portions 210 are arranged at predetermined intervals in the left-right direction (horizontal direction). The comb teeth 210 of the pair of electrodes 21 are alternately arranged in the left-right direction. An electric field is formed between the comb teeth 210 having different polarities.

  The capacitive sensor 1 according to this embodiment and the capacitive sensor according to the first embodiment have the same functions and effects with respect to parts having the same configuration. Further, according to the capacitive sensor 1 of the present embodiment, it is compared with the case where the capacitive sensor (see FIG. 1) of the first embodiment is linearly arranged (shown by a dotted line in FIG. 6B). And the area where a pair of electrodes 21 oppose can be made wide. That is, the electrode area S, that is, the capacitance C in the formula (1) can be increased. For this reason, as shown by the solid line in FIG. 6B, the detection sensitivity can be increased as a whole.

<Fourth embodiment>
The difference between the capacitive sensor of the present embodiment and the capacitive sensor of the first embodiment is that the pair of electrodes each have comb teeth extending in the left-right direction. It is. Here, only differences will be described.

  FIG. 7A shows a vertical sectional view of a fuel tank of an automobile in which the capacitive sensor of this embodiment is arranged. FIG. 7B is a schematic graph showing the voltage responsiveness to the change in the liquid level. In addition, about the site | part corresponding to Fig.3 (a) and FIG.3 (b), it shows with the same code | symbol. Further, the cover layer is omitted.

  As shown in FIG. 7A, the electrode 21 includes a plurality of comb teeth 211. The comb-tooth portion 211 has a narrow strip shape extending in the left-right direction (horizontal direction). The plurality of comb-tooth portions 211 are arranged at predetermined intervals in the vertical direction. The comb teeth 211 of the pair of electrodes 21 are alternately arranged in the vertical direction. An electric field is formed between the comb teeth 211 having different polarities.

  The capacitive sensor 1 according to this embodiment and the capacitive sensor according to the first embodiment have the same functions and effects with respect to parts having the same configuration. Further, according to the capacitive sensor 1 of the present embodiment, it is compared with the case where the capacitive sensor (see FIG. 1) of the first embodiment is linearly arranged (shown by a dotted line in FIG. 7B). Thus, the detection sensitivity can be moderated. That is, as the liquid level L changes, the capacitance between the pair of comb teeth 211 facing each other in the vertical direction changes at a time. For this reason, the slope of the correlation line (= change in liquid level / change in voltage. The smaller the slope, the higher the detection sensitivity). On the other hand, as the liquid level L changes, the capacitance between the pair of electrodes 21 facing in the left-right direction gradually changes. For this reason, the inclination of the correlation line becomes large. Thus, according to the capacitive sensor 1 of the present embodiment, it is possible to easily set a difference in detection sensitivity and obtain a stepped signal.

<Fifth embodiment>
The difference between the capacitive sensor of the present embodiment and the capacitive sensor of the first embodiment is that a pair of electrodes are arranged in a zigzag pattern in a single stroke. Here, only differences will be described.

  FIG. 8 shows a front view of the capacitive sensor of this embodiment. In addition, about the site | part corresponding to FIG. 1, it shows with the same code | symbol. For convenience of explanation, one electrode 21 is hatched. Further, the cover layer is omitted. As shown in FIG. 8, each of the pair of electrodes 21 is arranged in a zigzag shape (rectangular wave shape) that undulates in the vertical direction.

  The capacitive sensor 1 according to this embodiment and the capacitive sensor according to the first embodiment have the same functions and effects with respect to parts having the same configuration. Further, according to the capacitive sensor 1 of the present embodiment, a pair of electrodes 21 are opposed to each other as in the capacitive sensor of the third embodiment (see FIGS. 6A and 6B). The section to be performed can be widened. That is, the electrode area S, that is, the capacitance C in the formula (1) can be increased. For this reason, overall detection sensitivity can be increased.

<Sixth embodiment>
The difference between the capacitive sensor of the present embodiment and the capacitive sensor of the first embodiment is that a pair of electrodes are arranged in a zigzag pattern in a single stroke. Here, only differences will be described.

  FIG. 9 shows a front view of the capacitive sensor of this embodiment. In addition, about the site | part corresponding to FIG. 1, it shows with the same code | symbol. For convenience of explanation, one electrode 21 is hatched. Further, the cover layer is omitted. As shown in FIG. 9, each of the pair of electrodes 21 is arranged in a zigzag shape (rectangular wave shape) that undulates in the left-right direction (horizontal direction).

  The capacitive sensor 1 according to this embodiment and the capacitive sensor according to the first embodiment have the same functions and effects with respect to parts having the same configuration. In addition, according to the capacitive sensor 1 of the present embodiment, the detection sensitivity difference can be easily set, similarly to the capacitive sensor of the fourth embodiment (see FIGS. 7A and 7B). can do.

<Seventh embodiment>
The difference between the capacitance type sensor of the present embodiment and the capacitance type sensor of the first embodiment is that the capacitance type sensor is arranged in the pipe. Here, only differences will be described.

  FIG. 10 shows a front view of a pipe in which the capacitive sensor of this embodiment is arranged. In addition, about the site | part corresponding to FIG. 1, it shows with the same code | symbol. Further, the cover layer is omitted. As shown in FIG. 10, the pipe 91 has a cylindrical shape extending in the vertical direction. A powder (fluid) flows inside the pipe 91. The capacitive sensor 1 has a strip shape. The capacitive sensor 1 is spirally wound around the outer peripheral surface of the pipe 91.

  The capacitive sensor 1 according to this embodiment and the capacitive sensor according to the first embodiment have the same functions and effects with respect to parts having the same configuration. Further, according to the capacitive sensor 1 of the present embodiment, the type (material) of the powder inside the pipe 91 can be detected. Moreover, the capacitive sensor 1 is flexible. For this reason, the capacitive sensor 1 can be easily wound around the pipe 91 regardless of the curvature of the pipe 91.

<Eighth embodiment>
The difference between the capacitive sensor of this embodiment and the capacitive sensor of the first embodiment is that two capacitive sensors are arranged in the fuel tank. Here, only differences will be described.

  FIG. 11 shows a block diagram of the capacitive sensor of the present embodiment and the control device for the automobile. In addition, about the site | part corresponding to FIG. 1, FIG. 3 (a), it shows with the same code | symbol. As shown in FIG. 11, two capacitive sensors 1 a and 1 b are juxtaposed in the fuel tank 90. The capacitance type sensor 1a is for detecting the liquid level of gasoline. On the other hand, the capacitive sensor 1b is for detecting the oil type (fuel type, for example, high-octane, regular, light oil, etc.) of gasoline.

  The control device 23 is also used as two capacitance type sensors 1a and 1b. The capacitance of the capacitance type sensor 1 a related to the liquid level is converted into a voltage by the C / V conversion unit 230 a and transmitted to the calculation unit 231. The storage unit 232 stores a correlation table between voltage and liquid level. The computing unit 231 refers to the transmitted voltage in the correlation table and determines the liquid level.

  The capacitance of the capacitance type sensor 1b relating to the oil type is converted into a voltage by the C / V conversion unit 230b and transmitted to the calculation unit 231. The storage unit 232 stores a correlation table between voltage and oil type. The calculation unit 231 refers to the transmitted voltage in the correlation table and determines the oil type.

  The calculation unit 231 transmits the gasoline level to the calculation unit 800 of the control device 80 of the automobile. The storage unit 801 of the control device 80 stores the lower limit value of the liquid level. The calculation unit 800 compares the transmitted liquid level with the lower limit value. When the transmitted liquid level falls below the lower limit value, the calculation unit 800 drives a warning device 83 (for example, a fuel out warning lamp, an alarm, voice guidance, etc.).

  In addition, the calculation unit 231 transmits the oil type of gasoline to the calculation unit 800 of the automobile control device 80. The storage unit 801 of the control device 80 stores usable oil types. The calculation unit 800 determines whether or not the transmitted oil type is usable. When the transmitted oil type is not usable (for example, when light oil is accidentally put into a regular gasoline vehicle at a gas station), the calculation unit 800 displays a warning device 83 (for example, an oil type warning lamp). , Alarm, voice guidance, etc.).

  In addition, the calculation unit 231 transmits the oil type of gasoline to the calculation unit 800 of the automobile control device 80. The storage unit 801 of the control device 80 stores appropriate air-fuel ratio and ignition timing for each oil type. The calculation unit 800 selects an air-fuel ratio corresponding to the transmitted oil type, and drives the fuel injection device 81 (an injector, a throttle valve, etc.). In addition, the calculation unit 800 selects an ignition timing according to the transmitted oil type, and drives the ignition device 82 (ignition coil, spark plug, etc.).

<Ninth embodiment>
The difference between the capacitive sensor of the present embodiment and the capacitive sensor of the first embodiment is that detection sections having different electrode areas are set in the capacitive sensor. . Here, only differences will be described.

  FIG. 12 shows a front view of the capacitive sensor of the present embodiment. In addition, about the site | part corresponding to FIG. 1, it shows with the same code | symbol. As shown in FIG. 12, the capacitive sensor 1 of the present embodiment includes three detection sections A4 to A6 from the bottom to the top. When the electrode area S4 of the detection section A4, the electrode area S5 of the detection section A5, and the electrode area S6 of the detection section A6 are compared, the relationship of S5 <S4 <S6 is established. From equation (1), the larger the electrode area S, the greater the capacitance C. For this reason, detection sensitivity can be made high.

  Hereinafter, the capacitance type sensor of the present embodiment will be described with reference to FIGS. 5A and 5B of the second embodiment. As shown in FIG. 5A, three inclined sections 900 a to 900 c are arranged on the side surface 900 of the fuel tank 90 from the bottom to the top. When the inclination angle α1 of the inclined section 900a, the inclination angle α2 of the inclined section 900b, and the inclination angle α3 of the inclined section 900c with respect to the front-rear direction (horizontal direction) are compared, the relationship of α2 <α1 <α3 is established. Yes.

  A detection section A5 having a small electrode area S5 is arranged in the inclination section 900b having a small inclination angle α2. That is, in the inclined section 900b having the small inclination angle α2, the increase / decrease in the amount of gasoline G interposed between the pair of electrodes 21 with respect to the change in the liquid level L increases. For this reason, as shown by a dotted line in FIG. 5B, when a capacitive sensor (see FIG. 1) having a constant electrode area over the entire length in the vertical direction is used, the voltage responsiveness to the change in the liquid level L. Becomes higher. Therefore, the detection section A5 having a low detection sensitivity is assigned to the inclined section 900b where the voltage responsiveness tends to be high. For this reason, it can suppress that the detection sensitivity in the inclination area 900b becomes high too much.

  On the other hand, a detection section A6 having a large electrode area S6 is arranged in the inclination section 900c having a large inclination angle α3 (approximately 90 °). That is, in the inclined section 900c having a large inclination angle α3, the increase or decrease in the amount of gasoline G interposed between the pair of electrodes 21 with respect to the change in the liquid level L is small. For this reason, as shown by a dotted line in FIG. 5B, when a capacitive sensor (see FIG. 1) having a constant electrode area over the entire length in the vertical direction is used, the voltage responsiveness to the change in the liquid level L. Will be lower. Therefore, the detection section A6 with high detection sensitivity is assigned to the inclined section 900c where the voltage responsiveness tends to be low. For this reason, it can suppress that the detection sensitivity in the inclination area 900c becomes low too much. In addition, a detection section A4 having a medium detection sensitivity is assigned to the inclination section 900a having a medium inclination angle α1.

  The capacitive sensor 1 according to this embodiment and the capacitive sensor according to the first embodiment have the same functions and effects with respect to parts having the same configuration. Further, according to the capacitive sensor 1 of the present embodiment, as shown in FIG. 5A, three detection sections A4 to A6 having different electrode areas S4 to S6 are set. For this reason, as shown in FIG. 5 (b), the difference between the inclination angles α1 to α3 is shown in spite of the fact that three inclination sections 900a to 900c having different inclination angles α1 to α3 are arranged in the fuel tank 90. The difference between the electrode areas S4 to S6 can be offset. That is, the detection sensitivity in the three inclined sections 900a to 900c can be made uniform.

<Others>
The embodiment of the capacitive sensor of the present invention has been described above. However, the embodiment is not particularly limited to the above embodiment. Various modifications and improvements that can be made by those skilled in the art are also possible.

  For example, the detection sensitivity can be improved by appropriately combining the width of the interelectrode distances d4 to d6 (see FIG. 4) of the second embodiment and the size of the electrode areas S4 to S6 (see FIG. 12) of the ninth embodiment. You may adjust. This increases the degree of freedom in setting the detection sensitivity.

  The shape of the correlation line in FIG. 3B, FIG. 5B, FIG. 6B, and FIG. 7B does not have to be linear (polygonal). It may be curved. Further, in the fuel tank 90, the material of the fluid may be detected. Further, the fuel tank 90 may store powder or a gel-like body. Further, in the pipe 91, the level of the fluid may be detected. Further, a liquid or a gel-like body may be caused to flow in the pipe 91. Further, the capacitive sensor 1 may be disposed on the inner peripheral surface of the pipe 91. The fuel is not limited to gasoline. Heavy oil, kerosene, etc. may be used. The fluid is not limited to fuel and powder. It may be engine oil, transmission oil, cooling water, water, sand or the like. Transportation machines are not limited to cars. It may be a motorcycle, a ship, an airplane, or the like. Further, the curved shape of the capacitive sensor 1 is not particularly limited. In addition to the L shape shown in FIG. 3A, a C shape, a J shape, an S shape, a U shape, a V shape, a W shape, a Z shape, a sine wave shape, a rectangular wave shape, an arc shape, a spherical surface It may be a shape.

  The material of the base material 20 is not particularly limited. What is necessary is just to select suitably from resin and an elastomer. From the viewpoint of durability against repeated expansion and contraction and an increase in capacitance, an elastomer having a large elongation, strength, and relative dielectric constant is preferred. Examples thereof include silicone rubber, acrylonitrile-butadiene copolymer rubber, acrylic rubber, epichlorohydrin rubber, chlorosulfonated polyethylene, chlorinated polyethylene, urethane rubber, natural rubber, isoprene rubber, and foams thereof. The substrate 20 may be a resin (elastomer) sheet or a cloth (woven fabric, non-woven fabric) formed from fibers. By adjusting the elastic modulus of the substrate 20, the detection sensitivity can be adjusted according to the application. The elastomer may contain additives such as a plasticizer, a processing aid, a crosslinking agent, a crosslinking accelerator, a crosslinking aid, an anti-aging agent, a softening agent, and a colorant.

  Further, a resin may be used as the material of the base material 20. For example, polyester resin, modified polyester resin (urethane modified polyester resin, epoxy modified polyester resin, acrylic modified polyester resin, etc.), polyether urethane resin, polycarbonate urethane resin, vinyl chloride-vinyl acetate copolymer, phenol resin, acrylic resin, Polyamideimide resin, polyamide resin, nitrocellulose, and modified celluloses (cellulose / acetate / butyrate (CAB), cellulose / acetate / propionate (CAP), etc.).

  As the elastomer for the electrode 21, silicone rubber, acrylic rubber, ethylene-propylene copolymer rubber, natural rubber, styrene-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber, epichlorohydrin rubber, chlorosulfonated polyethylene, chlorinated Examples thereof include crosslinked rubbers such as polyethylene, urethane rubber, fluorine rubber, chloroprene rubber, and isobutylene isoprene rubber, and thermoplastic elastomers such as styrene, olefin, vinyl chloride, polyester, polyurethane, and polyamide.

  As the conductive material for the electrode 21, various conductive materials can be used. When metal particles are used as the conductive material, it is desirable that the elastomer does not contain any of sulfur, sulfur compounds, and organic peroxides from the viewpoint of suppressing oxidation and sulfurization of the metal particles. In this case, as the elastomer, it is desirable to use one or more selected from sulfur, a sulfur compound, a crosslinked rubber crosslinked without using an organic peroxide, and a thermoplastic elastomer.

  The former crosslinked rubber may be any rubber that is crosslinked without using a sulfur-containing vulcanizing agent, vulcanization accelerator, or peroxide-based crosslinking agent. Examples of such a crosslinked rubber include silicone rubber, hydrosilyl crosslinked ethylene-propylene-diene terpolymer (EPDM), amine crosslinked acrylic rubber, isocyanate crosslinked urethane rubber, and isocyanate crosslinked liquid butadiene rubber. Examples of the latter thermoplastic elastomer include polyester-based thermoplastic elastomer (TPEE), polyurethane-based thermoplastic elastomer (TPU), polyolefin-based thermoplastic elastomer (TPO), polyamide-based thermoplastic elastomer, styrene-based block copolymer-based thermoplastic elastomer ( SIS, SBS, etc.).

  The kind of conductive material is not particularly limited. One kind or two or more kinds of metal particles such as gold, silver, copper, nickel, rhodium, palladium, chromium, titanium, platinum, iron, and alloys thereof can be used. Carbon materials such as carbon black, carbon nanotubes, and graphite may be used. Moreover, you may use the covering particle | grains which coat | covered the surface of particle | grains other than a metal with the metal. In this case, it is possible to reduce the specific gravity of the conductive material as compared with the case where the conductive material is only made of metal. Therefore, when it is made into a paint, sedimentation of the conductive material is suppressed and dispersibility is improved. Also, by processing the particles, various shapes of conductive materials can be easily manufactured. In addition, the cost of the conductive material can be reduced. As the metal to be coated, metal materials such as gold listed above may be used. Further, as particles other than metal, carbon materials such as carbon black, metal oxides such as calcium carbonate, titanium dioxide, aluminum oxide, and barium titanate, inorganic substances such as silica, resins such as acrylic and urethane, and the like may be used. .

  What is necessary is just to determine suitably content of a electrically conductive material so that electroconductivity and a softness | flexibility can be made compatible. For example, from the viewpoint of ensuring conductivity, the content of the conductive material is desirably 10 vol% or more when the volume of the electrode 21 is 100 vol%. It is more preferable that it is 15 vol% or more. On the other hand, when the content of the conductive material increases, the flexibility decreases. For this reason, the content of the conductive material is desirably 40 vol% or less when the volume of the electrode 21 is 100 vol%. It is more preferable that it is 25 vol% or less.

  In the above embodiment, the electrode 21 and the cover layer 22 are formed by a screen printing method. The coating method of the paint is not particularly limited, and for example, a dipping method, a spray method, a bar coating method, or the like may be used in addition to a printing method such as ink jet printing, flexographic printing, gravure printing, pad printing, or lithography.

1: Capacitance type sensor, 1a: Capacitance type sensor, 1b: Capacitance type sensor.
20: base material, 21: electrode, 210: comb tooth part, 211: comb tooth part, 22: cover layer, 23: control device, 230: conversion part, 230a: conversion part, 230b: conversion part, 231: calculation part 232: Storage unit.
80: control device, 800: calculation unit, 801: storage unit, 81: fuel injection device, 82: ignition device, 83: warning device.
90: Fuel tank, 900: Side surface, 900a to 900c: Inclined section, 901: Bottom surface.
91: Piping.
α1 to α3: inclination angle, θ1 to θ3: inclination angle, A1 to A6: detection section, A2a: center, G: gasoline (fuel), L: liquid level (level), d4 to d6: distance between electrodes, S4 to S6: Electrode area.

Claims (14)

A resin or elastomer substrate;
A pair of electrodes comprising an elastomer and a conductive material, the electrodes being spaced apart from each other on one surface of the substrate;
With
A capacitance type sensor that detects a detection amount that is at least one of a level and a material of a fluid based on a change in capacitance between the pair of electrodes.   The capacitive sensor according to claim 1, further comprising a plurality of detection sections having different detection sensitivities. The detected amount is the level of the fluid;
The capacitive sensor according to claim 2, wherein the plurality of detection sections have different inclination angles with respect to a horizontal direction. The detected amount is the level of the fluid;
The capacitive sensor according to claim 2, wherein the plurality of detection sections have different distances between the pair of electrodes. The detected amount is the level of the fluid;
Each of the pair of electrodes has comb teeth extending in the vertical direction,
The capacitive sensor according to any one of claims 1 to 4, wherein the comb-tooth portions of the pair of electrodes are alternately arranged in the horizontal direction. The detected amount is the level of the fluid;
Each of the pair of electrodes has a comb tooth portion extending in the horizontal direction,
The capacitive sensor according to any one of claims 1 to 4, wherein the comb-tooth portions of the pair of electrodes are alternately arranged in a vertical direction.   The capacitive sensor according to claim 1, wherein the capacitive sensor is disposed on at least one of an outer peripheral surface and an inner peripheral surface of a pipe through which the fluid flows. The fluid is a fuel for a transport machine;
The detected amount is a fuel type that is the material of the fuel,
The capacitive sensor according to any one of claims 1 to 7, further comprising a control device that transmits the fuel type to the transport machine.   The capacitive sensor according to claim 1, wherein the electrode is formed from a paint including the elastomer and the conductive material.   The capacitive sensor according to claim 1, wherein the conductive material includes metal particles.   The capacitance type sensor according to any one of claims 1 to 10, wherein an elongation at the time of cutting of the substrate is 5% or more.   The elastomer of the substrate and the pair of electrodes is at least one selected from sulfur, a sulfur compound, a crosslinked rubber crosslinked without using an organic peroxide, and a thermoplastic elastomer. The capacitive sensor according to any one of the above.   The capacitive sensor according to claim 1, further comprising an elastomer cover layer disposed so as to cover the pair of electrodes.   The capacitive sensor according to claim 13, wherein the elastomer of the cover layer is one or more selected from sulfur, a sulfur compound, a crosslinked rubber crosslinked without using an organic peroxide, and a thermoplastic elastomer.

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