+

WO2017010135A1 - Capteur piézoélectrique - Google Patents

Capteur piézoélectrique Download PDF

Info

Publication number
WO2017010135A1
WO2017010135A1 PCT/JP2016/062250 JP2016062250W WO2017010135A1 WO 2017010135 A1 WO2017010135 A1 WO 2017010135A1 JP 2016062250 W JP2016062250 W JP 2016062250W WO 2017010135 A1 WO2017010135 A1 WO 2017010135A1
Authority
WO
WIPO (PCT)
Prior art keywords
piezoelectric
layer
particles
piezoelectric element
elastomer
Prior art date
Application number
PCT/JP2016/062250
Other languages
English (en)
Japanese (ja)
Inventor
高橋　渉
吉川　均
Original Assignee
住友理工株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 住友理工株式会社 filed Critical 住友理工株式会社
Priority to CN201680040559.4A priority Critical patent/CN107924986B/zh
Priority to JP2016550878A priority patent/JP6034543B1/ja
Priority to DE112016000917.8T priority patent/DE112016000917B4/de
Publication of WO2017010135A1 publication Critical patent/WO2017010135A1/fr

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/16—Measuring force or stress, in general using properties of piezoelectric devices
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/30—Piezoelectric or electrostrictive devices with mechanical input and electrical output, e.g. functioning as generators or sensors
    • H10N30/302—Sensors
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/80—Constructional details
    • H10N30/85—Piezoelectric or electrostrictive active materials
    • H10N30/852—Composite materials, e.g. having 1-3 or 2-2 type connectivity
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/80—Constructional details
    • H10N30/87—Electrodes or interconnections, e.g. leads or terminals
    • H10N30/877—Conductive materials
    • H10N30/878—Conductive materials the principal material being non-metallic, e.g. oxide or carbon based
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/80—Constructional details
    • H10N30/88—Mounts; Supports; Enclosures; Casings
    • H10N30/883—Additional insulation means preventing electrical, physical or chemical damage, e.g. protective coatings

Definitions

  • the present invention relates to a piezoelectric sensor including an extendable piezoelectric element.
  • Piezoelectric materials that can convert mechanical energy into electrical energy are widely used for pressure sensors, acceleration sensors, vibration sensors, impact sensors, and the like.
  • Known piezoelectric materials include ceramics such as lead zirconate titanate (PZT), polymers such as polyvinylidene fluoride (PVDF) and polylactic acid, and composites in which polymer particles are filled in a polymer matrix.
  • PZT lead zirconate titanate
  • PVDF polymers
  • Plactic acid polylactic acid
  • Patent Document 1 describes a piezoelectric element in which an electrode made of conductive rubber and a piezoelectric crystal thin film such as PZT are formed on a substrate having stretch elasticity.
  • Patent Document 2 describes a piezoelectric element having a piezoelectric layer made of a fluorinated polymer, an electrode made of a conductive polymer, and a textile substrate.
  • Patent Document 3 describes a piezoelectric element having a composite in which a matrix having a resin and rubber is filled with piezoelectric particles, and an electrode made of conductive rubber.
  • Patent Document 4 describes a piezoelectric element having a piezoelectric sheet in which piezoelectric particles are filled in a resin matrix such as chlorinated polyethylene, and a flexible electrode in which carbon is filled in chlorinated polyethylene.
  • Patent Document 5 describes a piezoelectric element having a composite in which chloroprene rubber is filled with lead titanate powder and an electrode made of silver paste.
  • Patent Document 6 describes a fluctuating load detection sheet having a PVDF piezoelectric film, a pair of electrodes disposed on both sides thereof, and a strain amplification member provided on the electrodes.
  • a piezoelectric element using ceramics such as PZT as a piezoelectric layer as described in Patent Document 1 has a hard piezoelectric layer and poor stretchability. For this reason, when the piezoelectric element is applied to an adherend that expands and contracts, the movement of the adherend tends to be hindered.
  • the piezoelectric elements described in Patent Documents 2 and 6 use a resin for the piezoelectric layer. For this reason, the piezoelectric layer has flexibility, but lacks stretchability. Even if the piezoelectric layer can be extended, it is difficult to restore the original shape. Therefore, it is difficult to apply the piezoelectric element to an adherend that undergoes expansion and deformation.
  • the piezoelectric elements described in Patent Documents 3 to 5 use a composite of a polymer matrix and piezoelectric particles in the piezoelectric layer.
  • a polymer when a polymer is contained in the polymer matrix, it has flexibility but poor stretchability.
  • chloroprene rubber is used for the polymer matrix.
  • the piezoelectric layer has stretchability, but the electrode laminated thereon is made of a silver paste with poor stretchability. In this case, the expansion and contraction of the piezoelectric layer is restricted by the electrode, and the stretchability of the entire piezoelectric element is reduced.
  • Patent Document 3 describes the use of conductive rubber for the electrodes. However, Patent Document 3 does not discuss the expansion / contraction performance of the electrode and the behavior of the electrical resistance during expansion. Further, paragraph [0020] of Patent Document 3 describes that the distortion amount of the vibration source is about 5%, and in the examples, an application example in which the distortion amount is 3% is described. In patent document 3, the piezoelectric element is not assumed to be deformed at a relatively large elongation rate of 10% or more.
  • This invention is made in view of such a situation, and makes it a subject to provide a piezoelectric sensor provided with the piezoelectric element which can be extended-contracted and can be used even in the extended state.
  • the piezoelectric sensor of the present invention includes a piezoelectric element having a piezoelectric layer including an elastomer and piezoelectric particles and an electrode layer including an elastomer and a conductive material, and the elongation at break of the piezoelectric element is 10% or more. Is characterized in that the volume resistivity of the stretched state from the natural state to the stretched state by 10% in the uniaxial direction is 100 ⁇ ⁇ cm or less.
  • the matrix (base material) of the piezoelectric layer and electrode layer constituting the piezoelectric element are both elastomers.
  • the elongation at break of the piezoelectric element is 10% or more. Since the piezoelectric element is flexible and stretchable, even if the piezoelectric element is arranged on an adherend that repeatedly stretches or bends or an adherend that greatly expands and contracts, the movement of the adherend is hardly hindered. Further, even when the adherend has a complicated shape, the piezoelectric element can be arranged along the shape.
  • the electrode layer has a volume resistivity of 100 ⁇ ⁇ cm or less in a natural state and a stretched state from that state to a state where the electrode layer is stretched by 10% in a uniaxial direction.
  • the natural state means a state in which no load is applied and the body is not deformed.
  • the state of extending 10% in the uniaxial direction means a state in which the length in the uniaxial direction is 1.1 times the natural state.
  • the electrode layer not only has high conductivity in a natural state, but also has a high electrical conductivity with a small increase in electrical resistance even in an extended state extended up to 10% in a uniaxial direction. For this reason, even in the extended state, the output is unlikely to decrease, and the load applied to the piezoelectric layer can be accurately detected.
  • the volume resistivity of the electrode is measured in both a natural state and a state in which the electrode is stretched by 10% in the uniaxial direction. If any volume resistivity is 100 ⁇ ⁇ cm or less, the “natural state and then the uniaxial direction” It is determined that the condition that the volume resistivity of the stretched state until reaching the stretched state by 10% is 100 ⁇ ⁇ cm or less ”is satisfied.
  • the piezoelectric element can extend not only in a uniaxial direction but also in a biaxial direction, a diameter expansion direction, and the like.
  • the adherend is disposed on the adherend accompanied by deformation such as bending, stretching, and compression, and the adherend is not only deformed but also deformed.
  • the load applied to can be detected. That is, even when the secondary deformation is further performed in the primary deformation state of the adherend, the load applied to the adherend can be detected.
  • the piezoelectric sensor of the present invention has a higher sensitivity (S / N ratio (Signal-Noise Ratio)) than a capacitive sensor, it is easy to detect a small load.
  • the piezoelectric element of the piezoelectric sensor of the present invention can be placed directly on the human skin or indirectly through clothes to measure the pulse rate and respiratory rate.
  • FIG. 2 is a sectional view taken along the line II-II in FIG. It is a graph of the electromotive voltage in the state which expanded the piezoelectric element of Example 2 1%. It is a graph of the electromotive voltage in the state which expanded the piezoelectric element of Example 2 10%. It is a schematic diagram which shows a dispersed state in case a piezoelectric particle consists of a single particle. It is a schematic diagram which shows a dispersion
  • SYMBOLS 1 Piezoelectric sensor, 10: Piezoelectric element, 11: Piezoelectric layer, 12a, 12b: Electrode layer, 13a, 13b: Protective layer, 20a, 20b: Wiring, 30: Control circuit part.
  • 40 Piezoelectric element, 41: Piezoelectric layer, 42a, 42b: Electrode layer, 43a, 43b: Protective layer.
  • 80 Piezoelectric particles, 81: Elastomer, 82: Combined piezoelectric particles.
  • the piezoelectric sensor of the present invention is not limited to the following forms, and may be implemented in various forms that have been modified or improved by those skilled in the art without departing from the spirit of the present invention. Can do.
  • the piezoelectric sensor of the present invention includes a piezoelectric element having a piezoelectric layer including an elastomer and piezoelectric particles and an electrode layer including an elastomer and a conductive material.
  • elastomer constituting the piezoelectric layer one or more selected from crosslinked rubber and thermoplastic elastomer may be used.
  • elastic elastomers with relatively small elastic modulus urethane rubber, silicone rubber, nitrile rubber (NBR), hydrogenated nitrile rubber (H-NBR), acrylic rubber, natural rubber, isoprene rubber, ethylene-propylene-diene rubber (EPDM) Ethylene-vinyl acetate copolymer, ethylene-vinyl acetate-acrylic ester copolymer, butyl rubber, styrene-butadiene rubber, fluororubber, epichlorohydrin rubber, chloroprene rubber, chlorinated polyethylene, chlorosulfonated polyethylene, and the like.
  • an elastomer modified by introducing a functional group or the like may be used.
  • the modified elastomer include carboxyl group-modified nitrile rubber (X-NBR), carboxyl group-modified hydrogenated nitrile rubber (XH-NBR), and the like.
  • Piezoelectric particles are particles of a compound having piezoelectricity.
  • Ferroelectric materials having a perovskite crystal structure are known as piezoelectric compounds, for example, barium titanate, strontium titanate, potassium niobate, sodium niobate, lithium niobate, potassium sodium niobate , Lead zirconate titanate (PZT), barium strontium titanate (BST), bismuth lanthanum titanate (BLT), bismuth strontium tantalate (SBT), and the like.
  • PZT Lead zirconate titanate
  • BST barium strontium titanate
  • BLT bismuth lanthanum titanate
  • SBT bismuth strontium tantalate
  • the particle size of the piezoelectric particles is not particularly limited.
  • a large particle size piezoelectric particle and a small particle size piezoelectric particle can be mixed in the elastomer.
  • piezoelectric particles having a small particle diameter enter between piezoelectric particles having a large particle diameter, and pressure is easily transmitted to the piezoelectric particles. Thereby, the piezoelectric strain constant of the piezoelectric layer is increased, and the electromotive voltage can be increased.
  • the piezoelectric particles may be single particles or an aggregate of a plurality of particles.
  • an aggregate composed of a plurality of piezoelectric particles it becomes easy to balance the flexibility and the piezoelectricity. For example, when a large amount of piezoelectric particles is blended in the elastomer, the piezoelectricity is improved, but the flexibility is lowered because the volume ratio of the elastomer is reduced. On the other hand, when the amount of the piezoelectric particles is small, the volume ratio of the elastomer increases, so that flexibility is improved, but piezoelectricity is lowered.
  • the change in electromotive force is reduced even when the expansion and contraction is repeated, that is, the expansion and contraction durability is improved by increasing the flexibility of the piezoelectric layer, specifically, the elongation at break. ing. For this reason, it is desirable to ensure the desired piezoelectricity by reducing the blending amount of the piezoelectric particles as much as possible.
  • FIG. 5 schematically shows a dispersion state when the piezoelectric particles are made of single particles.
  • FIG. 6 schematically shows a dispersion state in the case where the piezoelectric particles are made of an aggregate.
  • the piezoelectric particles 80 are filled in an elastomer 81.
  • Each piezoelectric particle 80 has a substantially spherical shape. For this reason, usually, the connection between the piezoelectric particles 80 is ensured by blending a large amount of the piezoelectric particles 80 and bringing them close to the close-packed structure.
  • FIG. 5 schematically shows a dispersion state when the piezoelectric particles are made of single particles.
  • FIG. 6 schematically shows a dispersion state in the case where the piezoelectric particles are made of an aggregate.
  • the piezoelectric particles 80 are filled in an elastomer 81.
  • Each piezoelectric particle 80 has a substantially spherical shape. For this reason, usually, the connection between the piezoelectric
  • the piezoelectric sensor includes a piezoelectric element having a piezoelectric layer including an elastomer and piezoelectric particles, and an electrode layer including an elastomer and a conductive material, and the piezoelectric particles include an aggregate in which a plurality of piezoelectric particles are aggregated. It is good to. According to this configuration, a flexible and highly sensitive piezoelectric sensor can be realized.
  • Examples of aggregates in which a plurality of piezoelectric particles are aggregated include aggregates in which individual particles are aggregated by an electrostatic force or the like, and aggregates in which individual particles are chemically bonded. The latter combination is preferred from the viewpoint that individual particles are difficult to separate and that a connection structure of piezoelectric particles can be easily constructed.
  • bonded_body is not specifically limited, For example, after baking the powder which consists of a single particle, it can grind
  • the remaining piezoelectric particles are dispersed in a good solvent and subjected to ultrasonic treatment.
  • the good solvent refers to a polar solvent that hardly precipitates when the piezoelectric particles are dispersed.
  • any solvent that has an SP value (solubility parameter) of 8 or more and 13 or less and can dissolve the elastomer may be used.
  • An example is 2-methoxyethanol.
  • An aggregate of a plurality of piezoelectric particles can be defined as a particle having a diameter larger than twice the average particle diameter of each piezoelectric particle.
  • the diameter (d2) of the aggregate a median diameter measured by a laser diffraction / scattering particle size distribution measuring apparatus is employed.
  • the average particle diameter (d1) of the piezoelectric particles a scanning electron microscope (SEM) photograph of the aggregate is taken, and the average value of the maximum diameters of 100 or more piezoelectric particles arbitrarily selected so as not to be biased is adopted. To do. And what satisfies 2d1 ⁇ d2 is an aggregate.
  • the elastomer and the piezoelectric particles may be chemically bonded by surface-treating the piezoelectric particles.
  • a surface treatment agent having a functional group capable of reacting with an elastomer polymer is reacted with the piezoelectric particles in advance, and the piezoelectric particles are mixed with the elastomer polymer.
  • Examples include a method in which a hydroxyl group is generated by dissolving with an acid, an alkali, or subcritical water, and then mixed with an elastomer polymer having a functional group capable of reacting with the hydroxyl group.
  • the piezoelectric particles When the piezoelectric particles are chemically bonded to the elastomer, the piezoelectric particles are unlikely to be displaced even when the expansion and contraction is repeated. In addition, since the piezoelectric particles are difficult to peel from the elastomer, fluctuations from the initial values of physical properties and output are reduced. Therefore, the output is stabilized and the sag resistance of the piezoelectric layer is improved. In addition, since the elongation at break of the piezoelectric layer is increased, it is possible to suppress a decrease in piezoelectric performance due to local fracture during elongation. As a result, high piezoelectric performance can be maintained even in the extended state.
  • the blending amount of the piezoelectric particles may be determined by taking into account the flexibility of the piezoelectric layer, and thus the piezoelectric element, and the piezoelectric performance of the piezoelectric layer. When the amount of the piezoelectric particles is increased, the piezoelectric performance of the piezoelectric layer is improved, but the flexibility is lowered. Therefore, it is desirable to adjust the blending amount of the piezoelectric particles so that desired flexibility can be realized in the combination of the elastomer and the piezoelectric particles to be used.
  • the piezoelectric layer may contain reinforcing particles having a relative dielectric constant smaller than that of the piezoelectric particles, in addition to the elastomer and the piezoelectric particles.
  • the relative permittivity of the reinforcing particles is preferably 100 or less, and more preferably 30 or less, on condition that the relative permittivity of the reinforcement particles is smaller than that of the piezoelectric particles.
  • the structure in which piezoelectric particles having a large relative dielectric constant are connected is easy to transmit external force to the piezoelectric particles, an improvement in the piezoelectric strain constant of the above-described formula (a) can be expected.
  • the piezoelectric particles having a large relative dielectric constant are connected, the dielectric constant of the entire piezoelectric layer is increased.
  • both the piezoelectric particles and the reinforcing particles are included in the piezoelectric layer, the connection between the piezoelectric particles having a large relative dielectric constant is divided by the intervening reinforcing particles having a smaller relative dielectric constant. Thereby, the raise of the dielectric constant as the whole piezoelectric layer can be suppressed.
  • the piezoelectric strain constant can be maintained. That is, when the reinforcing particles are included in the piezoelectric layer, the dielectric constant of the entire piezoelectric layer can be made smaller than when only the piezoelectric particles are included while maintaining the piezoelectric strain constant. Therefore, a large electromotive field can be obtained by the above-described formula (a).
  • the reinforcing particles particles having a large electric resistance are desirable.
  • the electrical resistance of the reinforcing particles is large, the dielectric breakdown strength of the piezoelectric layer is increased. Thereby, in the polarization process of the piezoelectric layer which will be described later, the processing time can be shortened by applying a high electric field. In addition, since the number of piezoelectric elements that are destroyed during the polarization process can be reduced, productivity is improved.
  • the reinforcing particles are chemically bonded to the elastomer.
  • a network of reinforcing particles is formed in the elastomer, impurity ions obtained by ionizing a crosslinking agent, an additive, moisture in the air, and the like are difficult to move, and the electric resistance of the piezoelectric layer is increased.
  • the chemical bond between the reinforcing particles and the elastomer can be realized, for example, by surface-treating the reinforcing particles.
  • a surface treatment agent having a functional group capable of reacting with an elastomer polymer is reacted with the reinforcing particles in advance, and the reinforcing particles are mixed with the elastomer polymer.
  • generating a hydroxyl group etc. is mentioned.
  • the reinforcing particles are chemically bonded to the elastomer, the reinforcing particles are unlikely to be displaced even if the expansion and contraction are repeated.
  • the reinforcing particles are difficult to peel off from the elastomer, fluctuations from the initial values of physical properties and output are reduced. Therefore, the output is stabilized and the sag resistance of the piezoelectric layer is improved.
  • the elongation at break of the piezoelectric layer is increased, it is possible to suppress a decrease in piezoelectric performance due to local fracture during elongation. As a result, high piezoelectric performance can be maintained even in the extended state.
  • the type of reinforcing particles is not particularly limited.
  • particles such as oxides such as titanium dioxide, silica, and barium titanate, rubber, and resin can be used.
  • the applied load may be attenuated by the resin particles and may not be transmitted to the piezoelectric particles.
  • the reinforcing particles From the viewpoint of facilitating transmission of force to the piezoelectric particles, increasing the piezoelectric strain constant of the piezoelectric layer in the above-described formula (a), and increasing the electromotive force, the reinforcing particles have an elastic modulus higher than that of the matrix elastomer. It is better to use large particles.
  • metal oxide particles such as titanium dioxide are preferable because they have a small relative dielectric constant and a large effect of improving dielectric breakdown resistance.
  • a sol-gel method is preferable because particles having low crystallinity and a low relative dielectric constant can be obtained.
  • the piezoelectric layer is manufactured by curing a composition obtained by adding a powder of a piezoelectric particle or a crosslinking agent to an elastomer polymer under predetermined conditions. Thereafter, the piezoelectric layer is subjected to polarization treatment. That is, a voltage is applied to the piezoelectric layer to align the polarization direction of the piezoelectric particles in a predetermined direction.
  • the thinner piezoelectric layer is desirable.
  • the thickness of the piezoelectric layer is preferably 200 ⁇ m or less, and more preferably 100 ⁇ m or less.
  • the thickness of the piezoelectric layer is desirably 10 ⁇ m or more, and more desirably 20 ⁇ m or more.
  • Electrode layer As the elastomer constituting the electrode layer, one or more selected from cross-linked rubber and thermoplastic elastomer may be used in the same manner as the elastomer of the piezoelectric layer.
  • the elastomer having a relatively small elastic modulus and good adhesion to the piezoelectric layer include acrylic rubber, silicone rubber, urethane rubber, urea rubber, fluorine rubber, and H-NBR.
  • the type of conductive material is not particularly limited.
  • electroconductive carbon materials such as metal nanowire which consists of metal carbide particle
  • particles coated with a metal such as silver-coated copper particles may be used.
  • the conductive material one of these can be used alone, or two or more can be mixed and used.
  • the electrode layer may contain a crosslinking agent, a dispersing agent, a reinforcing material, a plasticizer, an antiaging agent, a coloring agent, and the like as other components.
  • the volume resistivity of the electrode layer is 100 ⁇ ⁇ cm or less both in the natural state and in the stretched state from the stretched state to 10% in the uniaxial direction. More preferably, it is 10 ⁇ ⁇ cm or less.
  • the electric resistance of the electrode layer is large, the electromotive voltage generated in the piezoelectric layer drops at the electrode layer, and the output voltage becomes small. That is, the S / N ratio of the sensor decreases.
  • the output in the natural state and the output in the extended state are greatly different, which causes a problem that the load cannot be accurately detected. Therefore, it can be used even in a stretched state by combining a flexible piezoelectric layer that can stretch and maintain piezoelectricity even when stretched and a flexible electrode layer that can stretch and maintain conductivity even when stretched.
  • a piezoelectric element can be realized.
  • the blending amount of the conductive material may be appropriately determined so that the electrode layer can achieve a desired volume resistivity.
  • the amount of the conductive material is increased, the volume resistivity of the electrode layer can be reduced, but the flexibility is lowered.
  • Ketjen Black registered trademark
  • it is desirable that the blending amount of the conductive material is 5 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the elastomer.
  • the piezoelectric element is formed by laminating a piezoelectric layer and an electrode layer.
  • the pair of electrode layers may be arranged apart from each other in the polarization direction of the piezoelectric particles in the piezoelectric layer.
  • a pair of electrode layers may be arranged one on each of the two surfaces in the thickness direction of the piezoelectric layer.
  • the pair of electrode layers may be arranged separately on one surface intersecting with the thickness direction of the piezoelectric layer.
  • the electrode layer may be formed on the entire surface of the piezoelectric layer, or may be formed on only a part.
  • the breaking elongation of the piezoelectric element is 10% or more. More preferably, it is 30% or more.
  • the elongation at break is a value of elongation at break measured by a tensile test specified in JIS K6251: 2010. The tensile test is performed using a dumbbell-shaped No. 5 test piece and a tensile speed of 100 mm / min.
  • the elastic modulus of the piezoelectric element is desirably 10 MPa or more and 500 MPa or less.
  • the elastic modulus is a value calculated from a stress-elongation curve obtained by a tensile test specified in JIS K7127: 1999. The tensile test is performed using a test piece type 2 test piece and a tensile speed of 100 mm / min.
  • the piezoelectric element desirably satisfies the following formula (I) in a state where the piezoelectric element is stretched by 10% in the uniaxial direction.
  • the following formula (I) is an index indicating flexibility and whether or not it can be used at the time of extension. That is, a piezoelectric element satisfying the following formula (I) is flexible and can generate an electromotive force by deformation even when it is extended. On the other hand, when the following formula (I) is not satisfied, the change in the electromotive voltage when it expands is large, and accurate sensing becomes difficult.
  • V1 is an electromotive voltage (V) of the piezoelectric element in a natural state
  • V2 is an electromotive voltage (V) of the piezoelectric element in a state of being extended by 10% in a uniaxial direction.
  • the electromotive voltage V1 in the natural state may be measured as follows. First, the piezoelectric element is installed in a rebound resilience tester manufactured by Kobunshi Keiki Co., Ltd. in a natural state without stretching.
  • a steel ball having a diameter of 14 mm and a mass of 300 g suspended with a suspension length of 2000 mm is caused to make a pendulum movement with a swing width (distance from the test piece in the horizontal direction) of 15 mm and collide with the piezoelectric element.
  • the peak value of the electromotive voltage generated at the time of collision is measured with an oscilloscope (“TPS2012B” manufactured by Tektronix). This is repeated five times, and an average value of five times of the peak value of the electromotive voltage is set as the electromotive voltage V1 in the natural state.
  • the piezoelectric element was installed in a rebound resilience tester (same as above) in a state where the piezoelectric element was stretched by 10% in the uniaxial direction.
  • the electromotive voltage V2 is sufficient.
  • the piezoelectric element may have a protective layer in addition to the piezoelectric layer and the electrode layer.
  • the protective layer may be disposed so as to be stacked on at least the electrode layer of the piezoelectric layer and the electrode layer.
  • a protective layer may be disposed on one or both of the laminate direction outer side of the laminate of the piezoelectric layer and the electrode layer.
  • a protective layer may be disposed between electrode layers adjacent in the stacking direction.
  • the protective layer is preferably stretchable together with the piezoelectric layer and the electrode layer. It is desirable to use at least one kind selected from a crosslinked rubber and a thermoplastic elastomer for the protective layer. By disposing the protective layer made of elastomer, it is possible to ensure the insulation of the piezoelectric element and suppress the destruction of the piezoelectric element due to external mechanical stress. Further, as will be described later, the extension of the protective layer increases the strain of the piezoelectric layer, thereby improving the sensitivity of the sensor.
  • Examples of elastomers having a relatively small elastic modulus and good adhesion to the electrode layer include natural rubber, isoprene rubber, butyl rubber, acrylic rubber, silicone rubber, urethane rubber, urea rubber, fluorine rubber, NBR, and the like.
  • the protective layer has excellent sag resistance.
  • the protective layer plays a role of protecting the piezoelectric element from external mechanical stress, it is desirable that the protective layer is excellent in wear durability and tear durability.
  • the breaking elongation of the protective layer is larger than the breaking elongation of the piezoelectric layer.
  • a shearing force acts on the piezoelectric layer by extending the protective layer in the surface direction.
  • a tensile force in the surface direction is applied to the piezoelectric layer, and the distortion of the piezoelectric layer increases.
  • the amount of charge generated in the piezoelectric layer is increased, and the sensitivity of the sensor is improved.
  • the sensitivity improvement effect by the protective layer is more remarkable as the elastic modulus in the tensile direction of the protective layer is smaller.
  • the elastic modulus of the protective layer is smaller than the combined elastic modulus of a pair of laminates that are adjacent to the protective layer and that include a pair of electrode layers and a piezoelectric layer interposed therebetween.
  • the composite elastic modulus of a set of laminated bodies is the sum of the elastic modulus of the piezoelectric layer and the elastic modulus of the pair of electrode layers.
  • Elastic modulus can be obtained as the slope of a stress-elongation (strain) curve with stress on the vertical axis and elongation (strain) on the horizontal axis.
  • strain stress-elongation
  • strain elongation
  • Conventional piezoelectric ceramics represented by PZT and piezoelectric resins represented by PVDF and polylactic acid can only be used in a region where the elongation is extremely small. That's fine.
  • the piezoelectric sensor of the present invention is flexible and can be expanded and contracted, it is necessary to design in consideration of an elastic modulus in a region where the elongation rate is large (the strain is large).
  • the protective layer can be elastically deformed in a region where the elongation rate is 25% or less, and the elastic modulus of the protective layer in the region is desirably smaller than 50 MPa.
  • the elastic modulus of the protective layer in the region where the elongation rate is 25% or less is preferably less than 20 MPa, and more preferably less than 10 MPa.
  • the sensitivity improvement effect by the protective layer is more remarkable as the difference between the elastic modulus in the tensile direction of the protective layer and the elastic modulus in the tensile direction of the piezoelectric layer is smaller. Therefore, the protective layer and the pair of laminates composed of the pair of electrode layers and the piezoelectric layer interposed therebetween can be elastically deformed in a region where the elongation is 25% or less, and further, the elongation is 10%. It is desirable that the elastic modulus of the protective layer and the combined elastic modulus of the set of laminates in the region of 25% or less satisfy the following formula ( ⁇ -1). It is more preferable that the following formula ( ⁇ -2) is satisfied. When the protective layer and the set of laminates satisfy the formula ( ⁇ -1) or the formula ( ⁇ -2), the sensitivity of the sensor can be improved even when the protective layer is extended by 10% or more.
  • the Poisson's ratio of the elastomer is about 0.5.
  • the thickness of the protective layer the greater the distortion increasing effect of the piezoelectric layer, and the greater the sensitivity improving effect of the sensor.
  • the thickness of the protective layer is increased, the piezoelectric element is increased.
  • the thickness of a protective layer suitably according to an installation place or a use. For example, it may be 5 ⁇ m or more and 5 mm or less.
  • FIG. 1 shows a top view of the piezoelectric sensor of the present embodiment.
  • FIG. 2 is a cross-sectional view taken along the line II-II in FIG.
  • the protective layer 13a is shown in a transparent manner.
  • the piezoelectric sensor 1 includes a piezoelectric element 10 and a control circuit unit 30.
  • the piezoelectric element 10 includes a piezoelectric layer 11, a pair of electrode layers 12a and 12b, and a pair of protective layers 13a and 13b. The breaking elongation of the piezoelectric element 10 is 50%.
  • the piezoelectric layer 11 contains X-NBR and barium titanate particles.
  • the piezoelectric layer 11 has a square thin film shape.
  • the piezoelectric layer 11 is subjected to polarization treatment, and the barium titanate particles are polarized in the thickness direction (vertical direction) of the piezoelectric layer 11.
  • the electrode layer 12a includes acrylic rubber, conductive carbon black, and carbon nanotubes.
  • the electrode layer 12a has a square thin film shape.
  • the electrode layer 12 a is disposed on the upper surface of the piezoelectric layer 11.
  • a wiring 20a is connected to the right end of the electrode layer 12a.
  • the electrode layer 12b is made of the same material as the electrode layer 12a and has a square thin film shape.
  • the electrode layer 12 b is disposed on the lower surface of the piezoelectric layer 11.
  • a wiring 20b is connected to the right end of the electrode layer 12b.
  • the piezoelectric layer 11 and the electrode layers 12a and 12b have the same size.
  • the volume resistivity in a natural state of the electrode layers 12a and 12b is 0.2 ⁇ ⁇ cm, and the volume resistivity in a state where the electrode layers 12a and 12b are elongated by 10% in the left-right direction (uniaxial direction) is 0.1 ⁇ ⁇ cm.
  • the protective layer 13a is made of silicone rubber and has a square thin film shape.
  • the protective layer 13a is larger than the piezoelectric layer 11 and the electrode layers 12a and 12b, and covers the piezoelectric layer 11 and the electrode layers 12a and 12b from above.
  • the protective layer 13b is made of silicone rubber and has a square thin film shape.
  • the protective layer 13b is larger than the piezoelectric layer 11 and the electrode layers 12a and 12b, and covers the lower surface of the electrode layer 12b.
  • the electrode layer 12a and the control circuit unit 30 are electrically connected by a wiring 20a.
  • the electrode layer 12b and the control circuit unit 30 are electrically connected by the wiring 20b.
  • the matrix of the piezoelectric layer 11 and the electrode layers 12a and 12b constituting the piezoelectric element 10 are all elastomers.
  • the protective layers 13a and 13b are also made of an elastomer.
  • the elongation at break of the piezoelectric element 10 is 10% or more. Therefore, the piezoelectric element 10 is flexible and can be expanded and contracted. For this reason, even if it arrange
  • the electrode layers 12a and 12b have a volume resistivity of 100 ⁇ ⁇ cm or less in a natural state and a state in which the electrode layers 12a and 12b are stretched 10% in the uniaxial direction. That is, the electrode layers 12a and 12b not only have high conductivity in a natural state, but also have a high conductivity with a small increase in electrical resistance even in an extended state that extends up to 10% in a uniaxial direction. For this reason, even in the extended state, the output is unlikely to decrease, and the load applied to the piezoelectric layer 11 can be accurately detected.
  • the piezoelectric sensor 1 arrange
  • the load can be detected. That is, even when the secondary deformation is further performed in the primary deformation state of the adherend, the load applied to the adherend can be detected.
  • Piezoelectric sensor 1 has a higher sensitivity (S / N ratio) than a capacitive sensor, so it is easy to detect a small load. Further, since the load can be detected by a voltage value or a current value, the circuit configuration can be simplified as compared with the case where the load is detected from the capacitance. Further, since energization to the piezoelectric element 10 is unnecessary, a power source for driving is not necessary. Incidentally, if the capacitance of the piezoelectric element 10 is also measured, a function as a capacitance type sensor can be added to the piezoelectric sensor 1. For example, a static load such as a surface pressure distribution can be detected by a change in capacitance, and a dynamic load such as vibration can be detected by a change in voltage.
  • piezoelectric layers 1 to 4 100 parts by mass of a carboxyl group-modified hydrogenated nitrile rubber polymer (“Terban (registered trademark) XT8889” manufactured by LANXESS) as an elastomer was dissolved in acetylacetone to prepare a polymer solution. Next, barium titanate powder (“BT9DX-400” manufactured by Kyoritsu Material Co., Ltd.) as piezoelectric particles was added to the prepared polymer solution and kneaded.
  • Teban registered trademark
  • XT8889 barium titanate powder
  • the blending amount of the barium titanate powder with respect to 100 parts by mass of the polymer is 650 parts by mass for the piezoelectric layer 1, 480 parts by mass for the piezoelectric layer 2, and 350 for the piezoelectric layer 3.
  • the piezoelectric layer 4 was 800 parts by mass.
  • the kneaded material was repeatedly passed through three rolls five times to obtain a slurry.
  • 5 parts by mass of tetrakis (2-ethylhexyloxy) titanium as a cross-linking agent was added to the obtained slurry and kneaded with an air stirrer, and then the slurry was applied onto a substrate by a bar coating method. This was heated at 150 ° C. for 1 hour to produce piezoelectric layers 1 to 4 having a thickness of 50 ⁇ m.
  • piezoelectric layer 5 Except for using a polyurethane polymer (“N5139” manufactured by Tosoh Corporation) as an elastomer and using 2 parts by mass of polyisocyanate (“Coronate (registered trademark) HX” manufactured by Tosoh Corporation) as a crosslinking agent, A piezoelectric layer 5 was manufactured in the same manner as the piezoelectric layer 2.
  • a piezoelectric layer 7 was produced in the same manner as the piezoelectric layer 5 except that 1050 parts by mass of lead zirconate titanate powder (“PZT-ALT” manufactured by Hayashi Chemical Industry Co., Ltd.) was used as the piezoelectric particles.
  • PZT-ALT lead zirconate titanate powder
  • piezoelectric layer 8 A piezoelectric layer 8 was manufactured in the same manner as the piezoelectric layer 5 except that 350 parts by mass of potassium niobate powder (“Piezofine” manufactured by Furuuchi Chemical Co., Ltd.) was used as the piezoelectric particles.
  • piezoelectric layers 9 to 11 After adding 5 parts by mass of tetrakis (2-ethylhexyloxy) titanium as a crosslinking agent and titanium dioxide sol as reinforcing particles to the slurry used for the production of the piezoelectric layer 2 and kneading with an air stirrer, the slurry is obtained by a bar coating method. It was applied on the material. This was heated at 150 ° C. for 1 hour to produce piezoelectric layers 9 to 11 having a thickness of 50 ⁇ m.
  • the blending amount of the titanium dioxide sol with respect to 100 parts by mass of the polymer content of the slurry was 1 part by mass for the piezoelectric layer 9, 5 parts by mass for the piezoelectric layer 10, and 20 parts by mass for the piezoelectric layer 11. .
  • the titanium dioxide sol was manufactured as follows. First, 0.02 mol of acetylacetone was added to 0.01 mol of tetrai-propoxytitanium, an organometallic compound, for chelation. Next, 0.083 mol of isopropyl alcohol, 0.139 mol of methyl ethyl ketone, and 0.08 mol of water are added to the resulting chelated product, and the mixture is stirred. After the addition, the mixture is heated to 40 ° C. and further stirred for 2 hours. did. Then, it was allowed to stand at room temperature overnight to obtain a titanium dioxide sol.
  • piezoelectric layers 12, 13 A slurry in which reinforcing particles are dispersed is added to the slurry used for the production of the piezoelectric layer 2, and 5 parts by mass of tetrakis (2-ethylhexyloxy) titanium as a cross-linking agent is added and kneaded with an air stirrer. was applied on the substrate. This was heated at 150 ° C. for 1 hour to produce piezoelectric layers 12 and 13 having a thickness of 50 ⁇ m.
  • the blending amount of the slurry in which the reinforcing particles are dispersed with respect to 100 parts by mass of the polymer content of the slurry was 5 parts by mass for the piezoelectric layer 12 and 20 parts by mass for the piezoelectric layer 13 as shown in Table 2 below.
  • the slurry in which the reinforcing particles are dispersed was manufactured as follows. First, a titanium dioxide powder (anatase type, Wako Pure Chemical Industries, Ltd., product code 205-01715) as a reinforcing particle was added to a polymer solution prepared by dissolving a carboxyl group-modified hydrogenated nitrile rubber polymer (same as above) in acetylacetone. ) And kneaded. Next, the kneaded product was repeatedly passed through three rolls five times to obtain a slurry in which reinforcing particles were dispersed.
  • the piezoelectric layer 14 was formed in the same manner as the piezoelectric layers 1 to 4 except that 480 parts by mass of the powder a (a “BTD-UP” manufactured by Nippon Kagaku Kogyo Co., Ltd.) of barium titanate particles was used as the piezoelectric particles. Manufactured.
  • the piezoelectric layer 15 was manufactured in the same manner as the piezoelectric layers 1 to 4 except that 480 parts by mass of the powder b of the combination of barium titanate particles as the piezoelectric particles was used.
  • the combined powder b of the barium titanate particles used was a barium titanate powder (single particle powder, “BT-UP2” manufactured by Nippon Chemical Industry Co., Ltd.) for 180 minutes at 1050 ° C. Manufactured by grinding.
  • FIG. 7 shows an SEM photograph of the barium titanate powder (single particles) before firing.
  • FIG. 8 shows an SEM photograph of barium titanate powder b (combined body) after firing and pulverization. As shown in FIGS. 7 and 8, it can be confirmed that a combined body formed by aggregating a plurality of barium titanate particles is produced by firing and pulverizing.
  • piezoelectric layer a For comparison, a piezoelectric layer having a thickness of 40 ⁇ m made of PVDF (manufactured by Kureha Elastomer Co., Ltd.) was used as the piezoelectric layer a.
  • piezoelectric layer b a piezoelectric layer in which barium titanate particles are dispersed in an epoxy resin is defined as a piezoelectric layer b.
  • the piezoelectric layer b was manufactured as follows. First, 100 parts by mass of bisphenol A ("jER (registered trademark) 828" manufactured by Mitsubishi Chemical Corporation) is added with 4.8 parts by mass of a phenol novolac resin ("BRG # 558" manufactured by Showa Denko KK) as a curing agent. Next, 480 parts by mass of barium titanate powder (same as above) was added to the prepared polymer solution and kneaded, and the kneaded product was passed through three rolls five times to obtain a slurry. The obtained slurry was applied onto a substrate by a bar coating method, and this was heated at 150 ° C. for 1 hour to produce a piezoelectric layer b having a thickness of 50 ⁇ m.
  • jER registered trademark
  • BRG # 558 phenol novolac
  • Electrode layer 1 100 parts by mass of an epoxy group-containing acrylic rubber polymer (“Nipol (registered trademark) AR42W” manufactured by Nippon Zeon Co., Ltd.) as an elastomer was dissolved in butyl cellosolve acetate to prepare a polymer solution. Next, 10 parts by mass of conductive carbon black (“Ketjen Black EC600JD” manufactured by Lion Corporation) and 16 parts by mass of carbon nanotubes (“VGCF (registered trademark)” manufactured by Showa Denko KK) were added to the prepared polymer solution.
  • Nipol epoxy group-containing acrylic rubber polymer
  • AR42W manufactured by Nippon Zeon Co., Ltd.
  • a polyester acid amide amine salt as a dispersant were added and dispersed with a bead mill to prepare a conductive paint. Subsequently, the conductive paint was applied on a polyethylene terephthalate (PET) film subjected to a release treatment by a bar coating method. This was heated at 150 ° C. for 1 hour to produce an electrode layer having a thickness of 20 ⁇ m.
  • PET polyethylene terephthalate
  • Electrode layer 2 An electrode layer 2 was produced in the same manner as the electrode layer 1 except that a conductive paint was prepared without blending carbon nanotubes and a dispersant.
  • Electrode layer 3 The conductive carbon black was changed from “Ketjen Black EC600JD” manufactured by Lion Corporation to “# 3050B” manufactured by Mitsubishi Chemical Corporation, except that a conductive paint was prepared without blending carbon nanotubes and a dispersant.
  • the electrode layer 3 was produced in the same manner as the electrode layer 1.
  • Electrode layer 4 A silver paste (“Dotite (registered trademark) D-362” manufactured by Fujikura Kasei Co., Ltd.) was applied onto the release-treated PET film by a bar coating method. This was heated at 150 ° C. for 1 hour to produce an electrode layer 4 having a thickness of 20 ⁇ m.
  • Dotite (registered trademark) D-362 manufactured by Fujikura Kasei Co., Ltd.
  • Liquid A and B of silicone rubber polymer (“KE1935” manufactured by Shin-Etsu Chemical Co., Ltd.) are mixed at the same mass, degassed by vacuum degassing, and then released onto a PET film that has been subjected to release treatment. The coating method was applied. This was heated at 150 ° C. for 1 hour to produce a protective layer having a thickness of 10 ⁇ m.
  • piezoelectric elements were manufactured as follows by appropriately combining the manufactured piezoelectric layer, electrode layer, and protective layer.
  • electrode layers were respectively arranged on two surfaces (upper surface and lower surface) in the thickness direction of the piezoelectric layer, and the piezoelectric layer and the electrode layer were pressure-bonded using a laminator (“LPD3223” manufactured by Fuji Pla Co., Ltd.).
  • LPD3223 manufactured by Fuji Pla Co., Ltd.
  • the protective layer which performed the excimer process previously was laminated
  • FIG. 9 shows a vertical sectional view of the manufactured piezoelectric element.
  • the piezoelectric element 40 is formed by laminating a protective layer 43a, an electrode layer 42a, a piezoelectric layer 41, an electrode layer 42b, and a protective layer 43b in order from the top.
  • the manufactured piezoelectric element has a square-shaped detection part of 30 mm in length and width.
  • Tables 1 and 2 show the configuration, characteristics, and evaluation results of the manufactured piezoelectric elements.
  • ⁇ relative dielectric constant
  • volume resistivity volume resistivity
  • elastic modulus volume resistivity
  • elongation at break volume resistivity
  • electromotive force electromotive force
  • volume resistivity ( ⁇ ⁇ cm) Electric resistance value ( ⁇ ) ⁇ Cross sectional area of test piece (cm 2 ) / Distance between marked lines (cm) (c) (2) Volume resistivity in the stretched state Using a tensile tester (manufactured by Shimadzu Corporation), the test piece of the electrode layer was stretched in the length direction.
  • the electrical resistance between the marked lines was measured, and the volume resistivity was calculated according to the previous equation (c), which was taken as the volume resistivity when the electrode layer was extended by 10%.
  • the volume resistivity was calculated in the same manner for the case where the test piece was extended by 50%, and was taken as the volume resistivity when the electrode layer was extended by 50%.
  • the cross-sectional area of the test piece in the extended state was calculated on the assumption that the Poisson's ratio of the test piece was 0.5.
  • the piezoelectric element was subjected to a tensile test specified in JIS K 7127: 1999, and the elastic modulus was calculated from the obtained stress-elongation curve.
  • the tensile test was performed using a test piece type 2 test piece with a tensile speed of 100 mm / min.
  • the electromotive force was measured by a method similar to the pendulum type test defined in JIS K 6255: 2013. First, the piezoelectric element was installed in a rebound resilience tester manufactured by Kobunshi Keiki Co., Ltd. in a natural state. Next, a steel ball having a diameter of 14 mm and a mass of 300 g suspended with a suspension length of 2000 mm was caused to make a pendulum movement with a swing width (distance from the test piece in the horizontal direction) of 15 mm and collide with the piezoelectric element. Then, the peak value of the electromotive voltage generated at the time of collision was measured with an oscilloscope (“TPS2012B” manufactured by Tektronix).
  • TPS2012B oscilloscope
  • the piezoelectric element was installed in a rebound resilience tester (same as above) in a state where the piezoelectric element was stretched 10% in the uniaxial direction, and the average value of five times of the peak value of the electromotive force measured by the same method as described above was The electromotive voltage V2 was
  • the piezoelectric elements of Examples 1 to 8 in which reinforcing particles are not included in the piezoelectric layer will be described.
  • the breaking elongation of the piezoelectric elements was 40% or more.
  • the volume resistivity of the electrode layer was 3 ⁇ ⁇ cm or less at the natural state and 10% elongation, and 5 ⁇ ⁇ cm or less at 50% elongation.
  • the electrode layers constituting the piezoelectric elements of Examples 1 to 8 satisfy the condition that the volume resistivity in the natural state and the expanded state from the state to 10% in the uniaxial direction is 100 ⁇ ⁇ cm or less. I can judge.
  • the value of V2 / V1 is greater than 0.5%, which satisfies the condition of the above-described formula (I). Further, the rate of change in electromotive voltage after repeated expansion and contraction was 150% or less, and it was confirmed that the change in electromotive voltage was small even after repeated expansion and contraction and that the stretch durability was excellent. Further, when the elastic modulus of the piezoelectric element is large, there is a possibility that the movement of the adherend is hindered. In this regard, the elastic modulus of the piezoelectric elements of Examples 1 to 8 is 500 MPa or less. Therefore, as indicated by a circle in Table 1, it was confirmed that the piezoelectric elements of Examples 1 to 8 had good followability to the adherend and hardly hindered the movement of the adherend.
  • the elastic modulus is large as shown in Table 2, It did not restore to its original shape after stretching. For this reason, the electromotive voltage in an extended state could not be measured, and the stretch durability could not be evaluated. Further, in the piezoelectric element of Comparative Example 2, since the blending amount of the piezoelectric particles was large, the elastic modulus of the piezoelectric element was increased and the elongation at break was less than 10%. For this reason, the electromotive voltage in an extended state could not be measured, and the stretch durability could not be evaluated.
  • the volume resistivity of the electrode layer was greatly increased at the time of expansion, so that the electromotive voltage was greatly reduced.
  • the volume resistivity of the electrode layer was greatly increased at the time of expansion, and the electromotive voltage in the expanded state could be measured. Therefore, the stretch durability was not evaluated.
  • the piezoelectric elements of Examples 9 to 13 in which reinforcing particles are included in the piezoelectric layer will be described.
  • Table 2 the configurations of the piezoelectric elements of Examples 9 to 13 are the same as the configuration of the piezoelectric element of Example 3 except that reinforcing particles are blended in the piezoelectric layer. Therefore, like the piezoelectric element of Example 3, the piezoelectric elements of Examples 9 to 13 have a small change in electromotive voltage even after repeated expansion and contraction and are excellent in expansion and contraction durability.
  • the electromotive voltage in the natural state was larger than that of the piezoelectric element of Example 3. This is a great effect due to the incorporation of reinforcing particles.
  • the reinforcing particles have a hydroxyl group on the surface and are chemically bonded to the elastomer. For this reason, the rate of change in electromotive voltage after repeated expansion and contraction is further reduced.
  • the piezoelectric elements of Examples 14 and 15 using a bonded body in which individual particles are chemically bonded as piezoelectric particles will be described.
  • Tables 1 and 2 the configurations of the piezoelectric elements of Examples 14 and 15 are the same as the configurations of the piezoelectric element of Example 3 except that the piezoelectric particles used are different.
  • the elastic modulus was small and the elongation at break was large compared to the piezoelectric element of Example 3 using barium titanate particles (single particles).
  • the electromotive voltage of the piezoelectric elements of Examples 14 and 15 was larger than that of the piezoelectric element of Example 3.
  • the expansion / contraction durability of the piezoelectric elements of Examples 14 and 15 was equivalent to that of the piezoelectric element of Example 3.
  • the flexibility could be greatly improved while ensuring high piezoelectricity. This is because, when an aggregate of piezoelectric particles is used, a connection structure between the piezoelectric particles is easily formed, so that high piezoelectricity can be obtained without increasing the blending amount of the piezoelectric particles.
  • FIG. 10 shows the relationship between the volume ratio of barium titanate particles and the generated electric field.
  • FIG. 10 in the case of the combined body used in the piezoelectric layer 14, it can be seen that a large electric field is generated even at a low filling rate as compared with the single particles used in the piezoelectric layer 1.
  • a large electric field is generated even at a low filling rate as compared with the single particles before firing.
  • FIG. 3 is a graph of an electromotive voltage when vibration is applied in the thickness direction in a state where the piezoelectric element is extended by 1% in one direction of the plane direction.
  • FIG. 4 is a graph of an electromotive voltage when vibration is applied in the thickness direction in a state where the piezoelectric element is extended by 10% in one direction of the plane direction.
  • the electromotive voltage is indicated by a thick line, and the load is indicated by a thin line.
  • a sine wave-like vibration with a load pp of 1.7 N was applied to the piezoelectric element using a fatigue durability tester “APC-1000” manufactured by Asahi Seisakusho.
  • the piezoelectric element maintains the piezoelectric performance even in the extended state, and can detect the applied load.
  • Piezoelectric elements were manufactured by changing the type and thickness of the protective layer, and the electromotive voltages in the natural state and the extended state were measured.
  • the configuration of the piezoelectric element is protective layer / electrode layer / piezoelectric layer / electrode layer / protective layer, and the manufacturing method is as described above. The following three types were used as the protective layer.
  • Liquid A and B of silicone rubber polymer (“KE1935” manufactured by Shin-Etsu Chemical Co., Ltd.) are mixed at the same mass, degassed by vacuum degassing, and then released onto a PET film that has been subjected to release treatment. The coating method was applied. This was heated at 150 ° C. for 1 hour to produce a protective layer 2 having a thickness of 1 mm.
  • the protective layer 2 is different in thickness of the protective layer used in the piezoelectric elements of Examples 1 to 15 described above.
  • Table 3 shows the measurement results of the configuration of the piezoelectric element, the composite elastic modulus of the laminate, the elastic modulus and breaking elongation of the protective layer, and the electromotive voltage of the piezoelectric element.
  • the elastic modulus, elongation at break, and electromotive force were measured according to the methods described above.
  • the composite elastic modulus of the laminate is a value obtained by separately obtaining and adding the elastic modulus of the piezoelectric layer and the elastic modulus of the electrode layer.
  • the electromotive voltage in the 20% stretched state is an average value of five times of the peak value of the electromotive force measured by installing the piezoelectric element in a rebound resilience tester (same as above) in a state where the piezoelectric element is stretched by 20% in one axis direction.
  • the elastic modulus of the protective layers 1 and 2 is smaller than 10 MPa, and the protective layers 1 and 2 satisfy the above elastic modulus formula ( ⁇ ).
  • the piezoelectric element of Example 17 having the protective layer 1 and the piezoelectric element of Example 18 having the protective layer 2 both satisfy the expressions ( ⁇ -1) and ( ⁇ -2). Therefore, in the piezoelectric elements of Examples 17 and 18, the electromotive voltage was larger than that of the piezoelectric element of Example 16 having no protective layer. In the piezoelectric elements of Examples 17 and 18, it can be seen that the effect of increasing the distortion of the piezoelectric layer by the protective layer is fully exhibited.
  • the electromotive voltage was larger than that of the piezoelectric element of Example 15 having a protective layer thickness of 10 ⁇ m. This is presumably because the effect of increasing the distortion of the piezoelectric layer is increased by the increase in the thickness of the protective layer.
  • the protective layer 3 satisfies the above-described elastic modulus formula ( ⁇ ), but does not satisfy the formula ( ⁇ -1). For this reason, the electromotive voltage of the piezoelectric element of the reference example was the same level as that of the piezoelectric element of Example 16 having no protective layer.
  • the laminate exceeded the elastic region when the elongation ratio was 10% or more. That is, although the piezoelectric element of Comparative Example 6 has a flexible protective layer, it was confirmed that the piezoelectric element cannot be used for applications that greatly expand because the piezoelectric layer has poor flexibility.
  • the piezoelectric sensor of the present invention can be applied to an adherend that stretches or bends (repeatedly expands and contracts and bends), it is a wearable that measures a pulse rate, a respiration rate, etc. without disturbing the natural movement of the living body. It is suitable as a simple biological information sensor. In addition, it can be used not only in an unstretched state but also in a stretched state (measurable), so it can also be used in joints that require expansion and contraction in humans and robots, and in processes where the sensor installation surface extends and returns during the manufacturing process. Can do. Further, it is suitable as a pressure sensor for robots (including industrial and communication), medical use, nursing care, health use, sports equipment, and automobiles.
  • the piezoelectric sensor of the present invention is particularly suitable for application as a human-machine interface (HMI) that comes into contact with people.
  • HMI human-machine interface
  • sports equipment such as sportswear such as sportswear (wearable such as shoes and gloves) and sports equipment such as balls, bats, rackets, various armor, weight training, traveling equipment, etc.
  • sportswear such as sportswear (wearable such as shoes and gloves)
  • sports equipment such as balls, bats, rackets, various armor, weight training, traveling equipment, etc.
  • the training effect can be quantified without impairing the hit feeling.
  • Digitized data and information can be sent to an IOT (Internet of Things) device as a control means.
  • IOT Internet of Things

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Composite Materials (AREA)
  • Materials Engineering (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
  • General Electrical Machinery Utilizing Piezoelectricity, Electrostriction Or Magnetostriction (AREA)

Abstract

L'invention porte sur un capteur piézoélectrique (1) pourvu d'un élément piézoélectrique (10) qui comprend une couche piézoélectrique (11) contenant un élastomère et des particules piézoélectriques et qui comprend des couches d'électrode (12a, 12b) contenant un élastomère et un matériau conducteur. L'allongement à la rupture de l'élément piézoélectrique (10) est supérieur ou égal à 10 %, et la résistivité volumique des couches d'électrode (12a, 12b) dans l'état naturel et dans l'état allongé, dans lequel ces dernières sont allongées dans une direction axiale de jusqu'à 10 % par rapport à l'état naturel, est inférieure ou égale à 100 Ω.cm.L'élément piézoélectrique (10) est susceptible d'être allongé/contracté, et présente l'effet piézoélectrique même dans l'état allongé.
PCT/JP2016/062250 2015-07-16 2016-04-18 Capteur piézoélectrique WO2017010135A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
CN201680040559.4A CN107924986B (zh) 2015-07-16 2016-04-18 压电传感器
JP2016550878A JP6034543B1 (ja) 2015-07-16 2016-04-18 圧電センサ
DE112016000917.8T DE112016000917B4 (de) 2015-07-16 2016-04-18 Piezoelektrischer Sensor

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2015141858 2015-07-16
JP2015-141858 2015-07-16

Publications (1)

Publication Number Publication Date
WO2017010135A1 true WO2017010135A1 (fr) 2017-01-19

Family

ID=57757278

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2016/062250 WO2017010135A1 (fr) 2015-07-16 2016-04-18 Capteur piézoélectrique

Country Status (4)

Country Link
JP (1) JP6696885B2 (fr)
CN (1) CN107924986B (fr)
DE (1) DE112016000917B4 (fr)
WO (1) WO2017010135A1 (fr)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017221892A1 (fr) * 2016-06-23 2017-12-28 日本化学工業株式会社 Bourrage pour matériaux piézoélectriques, matériau piézoélectrique composite, élément piézoélectrique composite, bourrage pour matériaux piézoélectriques composites, et procédé de production de composé de niobates alcalins
WO2019044318A1 (fr) * 2017-08-29 2019-03-07 住友理工株式会社 Dispositif de détection de signes vitaux
JPWO2018047878A1 (ja) * 2016-09-06 2019-06-24 積水化学工業株式会社 圧電センサ
JP6714788B1 (ja) * 2018-09-26 2020-06-24 住友理工株式会社 静電容量センサ、その製造方法、および静電容量センサ用網目状柔軟電極
WO2020157999A1 (fr) 2019-01-31 2020-08-06 住友理工株式会社 Capteur piézoélectrique et son procédé de fabrication
JPWO2020261837A1 (fr) * 2019-06-28 2020-12-30
CN115014591A (zh) * 2022-06-24 2022-09-06 电子科技大学 一种ct增强扫描防外渗监测传感器、制备方法和监测设备
US11751477B2 (en) * 2019-10-25 2023-09-05 Interface Technology (Chengdu) Co., Ltd. Piezoelectric film, preparation method thereof and piezoelectric film sensor

Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2019056565A (ja) * 2017-09-19 2019-04-11 株式会社デンソー 振動検出器
JP7045777B2 (ja) * 2018-01-31 2022-04-01 住友理工株式会社 トランスデューサおよびそれを用いた発電システム
KR102079298B1 (ko) * 2018-03-13 2020-04-07 한국과학기술원 압전 에너지 하베스터 및 이의 제조방법
FR3082781B1 (fr) * 2018-06-21 2022-12-02 Michelin & Cie Pneumatique comprenant un composite piezoelectrique
FR3083005B1 (fr) 2018-06-21 2020-11-20 Michelin & Cie Dispositif en matrice elastomere comprenant des charges piezoelectriques et des electrodes
CN109247920B (zh) * 2018-09-06 2021-09-28 上海平脉科技有限公司 一种高灵敏度压力传感器
WO2020255024A1 (fr) * 2019-06-18 2020-12-24 Sabic Global Technologies B.V. Nouvelle composition piézoélectrique et films ayant des valeurs d33 élevées et une adhérence et une flexibilité améliorées
US11460362B2 (en) * 2019-07-23 2022-10-04 Toyota Motor Engineering & Manufacturing North America, Inc. Flexible printed pressure transducer with sensor diffusion stack materials and methods incorporating the same
JP2021053169A (ja) * 2019-09-30 2021-04-08 住友理工株式会社 圧電センサおよび生体情報取得用衣服
FR3105589B1 (fr) * 2019-12-23 2022-12-30 Michelin & Cie Dispositif piezoelectrique ayant des proprietes piezoelectriques ameliorees
TWI751524B (zh) * 2020-04-10 2022-01-01 馗鼎奈米科技股份有限公司 壓電薄膜之電極化方法
DE102020121337A1 (de) * 2020-08-13 2022-02-17 Tdk Electronics Ag Piezoelektrischer Wandler und Verfahren zur Einstellung der elektromechanischen Eigenschaften eines piezoelektrischen Wandlers
AT526049B1 (de) * 2022-11-30 2023-11-15 Net Automation Gmbh Vorrichtung zum Erfassen der Druckkräfte zwischen zwei unter Krafteinwirkung aneinander anstellbaren Körpern
WO2024195565A1 (fr) * 2023-03-22 2024-09-26 三菱ケミカル株式会社 Feuille piézoélectrique stratifiée

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008160045A (ja) * 2006-11-30 2008-07-10 Matsushita Electric Ind Co Ltd 可撓性感圧体とそれを用いた圧電素子およびその製造方法
JP2011083122A (ja) * 2009-10-07 2011-04-21 Konica Minolta Holdings Inc アクチュエータ
JP2012251896A (ja) * 2011-06-03 2012-12-20 Tokai Rubber Ind Ltd 柔軟電極構造、および柔軟電極構造を有する電極を備えるトランスデューサ
US20140260653A1 (en) * 2013-03-15 2014-09-18 Brigham Young University Composite material used as a strain gauge
JP2015189776A (ja) * 2014-03-27 2015-11-02 住友理工株式会社 誘電膜およびそれを用いたトランスデューサ

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2552972A1 (fr) * 2004-10-28 2006-04-28 Matsushita Electric Industrial Co., Ltd. Element piezoelectrique et methode pour le fabriquer
KR100695727B1 (ko) * 2005-06-10 2007-03-15 (주)피에조랩 압전 복합체 센서
JP5046367B2 (ja) * 2006-10-23 2012-10-10 公益財団法人鉄道総合技術研究所 圧電材とその製造方法、制振装置及び駆動装置
JP5186160B2 (ja) * 2007-08-31 2013-04-17 東海ゴム工業株式会社 柔軟電極およびそれを用いたアクチュエータ
ITRM20110461A1 (it) * 2011-09-07 2013-03-08 Pielleitalia S R L "materiale composito comprendente uno strato di materiale piezoelettrico polimerico accoppiato con un substrato tessile e procedimento per realizzare detto materiale composito"
WO2013047875A1 (fr) * 2011-09-30 2013-04-04 富士フイルム株式会社 Film de convertisseur électroacoustique, dispositif d'affichage flexible, microphone de corde vocale et capteur d'instrument musical
KR20140007955A (ko) * 2011-10-17 2014-01-20 도카이 고무 고교 가부시키가이샤 유전막 및 그것을 사용한 트랜스듀서
JP5924405B2 (ja) * 2012-04-17 2016-05-25 株式会社村田製作所 押圧力センサ
JPWO2014080470A1 (ja) * 2012-11-21 2017-01-05 住友理工株式会社 柔軟導電部材およびそれを用いたトランスデューサ

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008160045A (ja) * 2006-11-30 2008-07-10 Matsushita Electric Ind Co Ltd 可撓性感圧体とそれを用いた圧電素子およびその製造方法
JP2011083122A (ja) * 2009-10-07 2011-04-21 Konica Minolta Holdings Inc アクチュエータ
JP2012251896A (ja) * 2011-06-03 2012-12-20 Tokai Rubber Ind Ltd 柔軟電極構造、および柔軟電極構造を有する電極を備えるトランスデューサ
US20140260653A1 (en) * 2013-03-15 2014-09-18 Brigham Young University Composite material used as a strain gauge
JP2015189776A (ja) * 2014-03-27 2015-11-02 住友理工株式会社 誘電膜およびそれを用いたトランスデューサ

Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11239409B2 (en) 2016-06-23 2022-02-01 Nippon Chemical Industrial Co., Ltd. Piezoelectric material filler, composite piezoelectric material, composite piezoelectric device, composite piezoelectric material filler, and method for producing alkali niobate compound
WO2017221892A1 (fr) * 2016-06-23 2017-12-28 日本化学工業株式会社 Bourrage pour matériaux piézoélectriques, matériau piézoélectrique composite, élément piézoélectrique composite, bourrage pour matériaux piézoélectriques composites, et procédé de production de composé de niobates alcalins
US11659768B2 (en) 2016-06-23 2023-05-23 Nippon Chemical Industrial Co., Ltd. Piezoelectric material filler, composite piezoelectric material, composite piezoelectric device, composite piezoelectric material filler, and method for producing alkali niobate compound
JPWO2018047878A1 (ja) * 2016-09-06 2019-06-24 積水化学工業株式会社 圧電センサ
JP7271084B2 (ja) 2016-09-06 2023-05-11 積水化学工業株式会社 圧電センサ
WO2019044318A1 (fr) * 2017-08-29 2019-03-07 住友理工株式会社 Dispositif de détection de signes vitaux
JP2019037672A (ja) * 2017-08-29 2019-03-14 住友理工株式会社 生体情報検出装置
JP6714788B1 (ja) * 2018-09-26 2020-06-24 住友理工株式会社 静電容量センサ、その製造方法、および静電容量センサ用網目状柔軟電極
US11737710B2 (en) 2019-01-31 2023-08-29 Sumitomo Riko Company Limited Piezoelectric sensor and method for manufacturing the same
WO2020157999A1 (fr) 2019-01-31 2020-08-06 住友理工株式会社 Capteur piézoélectrique et son procédé de fabrication
CN114009062A (zh) * 2019-06-28 2022-02-01 富士胶片株式会社 压电薄膜
US20220109098A1 (en) * 2019-06-28 2022-04-07 Fujifilm Corporation Piezoelectric film
JP7217807B2 (ja) 2019-06-28 2023-02-03 富士フイルム株式会社 圧電フィルム
WO2020261837A1 (fr) * 2019-06-28 2020-12-30 富士フイルム株式会社 Film piézoélectrique
JPWO2020261837A1 (fr) * 2019-06-28 2020-12-30
TWI828913B (zh) * 2019-06-28 2024-01-11 日商富士軟片股份有限公司 壓電薄膜
US11910719B2 (en) 2019-06-28 2024-02-20 Fujifilm Corporation Piezoelectric film
US11751477B2 (en) * 2019-10-25 2023-09-05 Interface Technology (Chengdu) Co., Ltd. Piezoelectric film, preparation method thereof and piezoelectric film sensor
CN115014591A (zh) * 2022-06-24 2022-09-06 电子科技大学 一种ct增强扫描防外渗监测传感器、制备方法和监测设备
CN115014591B (zh) * 2022-06-24 2024-05-17 电子科技大学 一种ct增强扫描防外渗监测传感器、制备方法和监测设备

Also Published As

Publication number Publication date
DE112016000917T5 (de) 2017-11-09
CN107924986A (zh) 2018-04-17
DE112016000917B4 (de) 2020-12-31
JP6696885B2 (ja) 2020-05-20
CN107924986B (zh) 2021-02-23
JP2017028323A (ja) 2017-02-02

Similar Documents

Publication Publication Date Title
JP6696885B2 (ja) 圧電センサ
JP6886266B2 (ja) 柔軟な圧電材料を用いたトランスデューサ
JP5633769B1 (ja) 柔軟なトランスデューサ
JP6249852B2 (ja) 誘電膜の製造方法
US20140090884A1 (en) Elastic conductive material
WO2012050128A1 (fr) Matériau conducteur souple et transducteur, carte à circuit imprimé souple, et protection électromagnétique utilisant ledit matériau conducteur souple
JP5711124B2 (ja) 柔軟導電材料およびトランスデューサ
JP2014118481A (ja) 導電材料およびそれを用いたトランスデューサ
JP2009227985A (ja) エラストマートランスデューサーおよび導電性ゴム組成物ならびに誘電性ゴム組成物
KR20140007955A (ko) 유전막 및 그것을 사용한 트랜스듀서
Natarajan et al. Robust triboelectric generators by all-in-one commercial rubbers
JP6487507B2 (ja) 生体情報検出装置
WO2019150850A1 (fr) Transducteur et système de génération de puissance utilisant ce dernier
JP5464808B2 (ja) 誘電材料およびそれを用いたアクチュエータ
US11737710B2 (en) Piezoelectric sensor and method for manufacturing the same
WO2021065085A1 (fr) Capteur piézo-électrique et vêtement d'acquisition de bioinformations
JP6034543B1 (ja) 圧電センサ
JP6002524B2 (ja) トランスデューサ
JP2018054590A (ja) 伸縮性コンデンサおよび変形センサ
JP7079704B2 (ja) 圧電センサ
JP6666958B2 (ja) 静電容量型伸びセンサシステム

Legal Events

Date Code Title Description
ENP Entry into the national phase

Ref document number: 2016550878

Country of ref document: JP

Kind code of ref document: A

121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 16824116

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 112016000917

Country of ref document: DE

122 Ep: pct application non-entry in european phase

Ref document number: 16824116

Country of ref document: EP

Kind code of ref document: A1

点击 这是indexloc提供的php浏览器服务，不要输入任何密码和下载