JP2007201388A - Piezoelectric element and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric element that controls a change in electric characteristics, even if employed under a high temperature and high humidity environment, realizes stable piezoelectric characteristics at all times, and uses a flexible pressure-sensitive body that dispenses with the need for complex circuits; and to provide a method for manufacturing the same. <P>SOLUTION: The piezoelectric element, including a flexible pressure sensitive body 1 having a piezoelectric ceramic powder 3 containing Group I and Group II elements in the periodic table and a flexible organic polymer 4, an electrode 2A connected to the flexible pressure-sensitive body 1, and an electrode 2B that is insulated from the electrode 2A. Changes in the electrical resistance and piezoelectric characteristics of the piezoelectric element are prevented, and the durability and reliability can be improved by removing the components eluted from the piezoelectric ceramic powder 3, containing the Group I and Group II elements in the periodic table by cleaning treatment. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a flexible pressure-sensitive body obtained by blending a piezoelectric ceramic powder in an organic polymer, and more particularly to a piezoelectric element used as a flexible pressure-sensitive sensor and a manufacturing method thereof.

This flexible pressure-sensitive body is obtained by uniformly dispersing, mixing and kneading the above materials using a processing machine such as a kneader or a roll, and is flexible because it contains a thermoplastic elastomer such as chlorinated polyethylene. It is processed as a sheet or cable and used as a piezoelectric element.
In the sheet-like piezoelectric element, first, piezoelectric powder and chlorinated polyethylene are kneaded with a roll, and then a flexible pressure-sensitive body is formed into a sheet shape by hot pressing, and a silver paste is applied to both surfaces of the sheet or applied to rubber. A pair of electrodes is formed by fusing a conductive sheet in which carbon is dispersed, and then obtained by applying a DC voltage of several tens of kV between both electrodes in order to develop a piezoelectric property. be able to. When pressure is applied to a part or the entire surface of this electrode, the flexible pressure-sensitive body in that part is distorted. As a result, a voltage is induced between both electrodes, and the pressure is detected using this induced voltage. Therefore, it is applied as a pressure sensor.
JP-A-62-230071

However, when a conventional piezoelectric element is used in a high-temperature and high-humidity environment, water vapor passes through the electrode and reaches the flexible pressure-sensitive body constituting the piezoelectric element. When the temperature inside the flexible pressure sensing element is lower than the outside or when the water vapor becomes supersaturated on the surface of the flexible pressure sensing element, the diffused water vapor condenses to produce water, and the flexible pressure sensing element A phenomenon occurs in which components and impurities of the constituent piezoelectric ceramic powder are eluted by water and ionized. As a result, there is a problem that electrical characteristics such as electrical resistance and piezoelectric characteristics change, and there is a problem that durability is inferior, and when used as a sensor, a circuit for detection and control becomes complicated. There was a problem.
In particular, piezoelectric ceramic powders containing alkali metals and alkaline earth metals belonging to Groups 1 and 2 of the periodic table have a low specific resistance and are easily eluted into water, so that a reduction in electrical resistance is a major issue.
In addition, although the said subject was described with respect to the sheet-like piezoelectric element, it has the same subject also in the case of a cable shape and another shape.

  The present invention solves the conventional problems, and even when used in a high-temperature and high-humidity environment, it suppresses the change in electrical characteristics, always realizes stable piezoelectric characteristics, and does not require a complicated circuit. An object of the present invention is to provide a piezoelectric element using a flexible pressure sensitive body and a method for manufacturing the same.

In order to solve the conventional problems, the piezoelectric element of the present invention has a flexible feeling including at least a piezoelectric ceramic powder containing elements of Group 1 and Periodic Table 2 and a flexible organic polymer. A pressure body, a first electrode connected to the flexible pressure-sensitive body, and a second electrode connected to the flexible pressure-sensitive body and insulated from the first electrode. The component eluted from the piezoelectric ceramic powder containing the elements of Group 2 of the periodic table is removed.
As a result, even if the piezoelectric element is used in a high-temperature and high-humidity environment, even if water vapor is condensed inside the piezoelectric element to generate water, the components that elute from the piezoelectric ceramic powder are removed, so the piezoelectric element is condensed into the condensed water. The elution of the elution component from the ceramic powder can be suppressed, and changes in the electrical resistance and piezoelectric characteristics of the piezoelectric element can be prevented. As a result, stable electrical characteristics can be maintained over a long period of time, and a circuit for detection and control when used as a sensor can be simplified.

  In addition, since the first electrode and the second electrode can prevent the diffusion of water vapor, the amount of water to be condensed is reduced, and the amount of water penetrating into the flexible pressure sensitive body can be reduced. Changes in electrical characteristics and piezoelectric characteristics can be further reduced, and durability and reliability can be further improved.

  The piezoelectric element using the flexible pressure sensitive body of the present invention and the manufacturing method thereof can reduce the elution of the component that lowers the electrical resistance from the piezoelectric ceramic powder by removing the component eluted from the piezoelectric ceramic powder in advance. Therefore, the initial electrical characteristics and piezoelectric characteristics can be maintained, and changes with time can be prevented. As a result, excellent durability and reliability can be realized.

  According to a first aspect of the present invention, there is provided a flexible pressure-sensitive body including a piezoelectric ceramic powder containing at least an element of Group 1 of the periodic table and Group 2 of the periodic table and a flexible organic polymer, and the flexible pressure-sensitive body. A first electrode connected to the flexible pressure-sensitive body and a second electrode connected to the flexible pressure-sensitive body and insulated from the first electrode, and includes elements of the first group of the periodic table and the second group of the periodic table in advance. By removing the components that elute from the piezoelectric ceramic powder, the piezoelectric element is used in a high-temperature and high-humidity environment, and even if water vapor is generated by condensation inside the piezoelectric element, the components eluted from the piezoelectric ceramic powder. Elution can be suppressed, so that changes in the electrical resistance and piezoelectric characteristics of the piezoelectric element can be prevented, stable electrical characteristics can be maintained over a long period of time, and for detection and control when used as a sensor. Simplify the circuit It is possible.

In the second aspect of the invention, in particular, the first electrode and the second electrode of the first aspect of the invention cover the flexible pressure sensitive body, and further include a protective layer covering at least the first electrode and the second electrode.
In the third invention, in particular, the flexible pressure-sensitive body of the first or second invention covers the first electrode, the second electrode covers the flexible pressure-sensitive body, and a protective layer covers at least the second electrode. It is set as the structure further provided.

  According to the configurations of the second invention and the third invention, the amount of water diffused by the first electrode, the second electrode, and the protective layer can be reduced because the amount of water vapor that reaches the surface of the flexible pressure sensitive body can be reduced. Since the amount of water penetrating into the flexible pressure sensitive body can be reduced, changes in the electrical characteristics and piezoelectric characteristics of the piezoelectric element can be further reduced, further improving durability and reliability. be able to.

  The fourth invention, in particular, includes at least one of barium, sodium, potassium, bismuth, and lithium in the piezoelectric ceramic powder containing the elements of Groups 1 and 2 of the periodic table of the first to third inventions. Since the relative permittivity of the piezoelectric ceramic powder can be lowered by the configuration, a high voltage is applied to the piezoelectric ceramic powder when performing a poling process for applying a DC voltage to develop the piezoelectric characteristics. Therefore, the polling efficiency can be increased and the voltage output constant can be increased. As a result, when the piezoelectric element is used as a pressure-sensitive sensor, the output voltage of the sensor with respect to the applied pressure can be increased, so that the sensitivity can be improved.

According to a fifth aspect of the invention, in particular, piezoelectric ceramic powders containing elements of Groups 1 and 2 of the Periodic Table of the first to fourth aspects are converted to sodium niobate, potassium niobate, lithium niobate, bismuth titanate. -By including at least one of sodium, barium titanate, and bismuth titanate, the dielectric constant of the piezoelectric ceramic powder can be further reduced, so that the poling efficiency for expressing the piezoelectric characteristics is further increased. In addition, since the amplification factor of the detection circuit can be lowered by increasing the sensitivity of the sheet-like piezoelectric element, when the piezoelectric element is used as a pressure-sensitive sensor, the output of the sensor with respect to the applied pressure Since the voltage can be increased, the sensitivity can be improved and a pressure sensitive sensor that is strong against electrical noise can be obtained. Kill.

  The sixth invention comprises (A) a step of kneading a piezoelectric ceramic powder containing at least an element of Group 1 of the periodic table and an element of Group 2 of the periodic table and a flexible organic polymer, and (B) at least the kneading step. Forming a flexible pressure sensitive body from a piezoelectric ceramic powder containing an element of Group 1 and Periodic Table 2 and a flexible organic polymer; and (C) connected to the flexible pressure sensitive body. Providing a first electrode, (D) providing a second electrode connected to the flexible pressure-sensitive body so as to be insulated from the first electrode, and (E) a periodic table group 1 and a periodic table. And a step of removing a component eluted from the piezoelectric ceramic powder containing a Group 2 element.

  In the seventh invention, in particular, in Step C and Step D of the sixth invention, the first electrode and the second electrode are configured to cover the flexible pressure-sensitive body, and at least the first electrode and the second electrode The present invention relates to a method for manufacturing a piezoelectric element, further comprising a step of providing a protective layer covering the substrate.

  In the eighth invention, in particular, in Step C of the sixth invention, the first electrode is provided so as to be covered with the flexible pressure-sensitive body, and in Step D, the second electrode covers the flexible pressure-sensitive body. And a method of manufacturing a piezoelectric element, further comprising a step of providing a protective layer that covers at least the first electrode and the second electrode.

  In the ninth invention, in particular, in step E of the sixth to eighth inventions, a component eluted from the piezoelectric ceramic powder containing elements of the periodic table group 1 and periodic table group 2 is removed, and after the step E, The present invention relates to a method for manufacturing a piezoelectric element that performs Step A.

  In the tenth aspect of the invention, in particular, after step A of the sixth to eighth aspects, in step E, the piezoelectric material that removes components eluted from the piezoelectric ceramic powder containing elements of the periodic table group 1 and periodic table group 2 is removed. The present invention relates to a method for manufacturing an element.

  In the eleventh aspect of the invention, in particular, after Step B of the sixth to eighth aspects, in Step E, the piezoelectric material that removes components eluted from the piezoelectric ceramic powder containing the elements of Group 1 and Group 2 of the periodic table is removed. The present invention relates to a method for manufacturing an element.

  In particular, the twelfth invention relates to a piezoelectric element configured to remove components eluted from the piezoelectric ceramic powder by a cleaning process in the first to eleventh inventions, and a method for manufacturing the piezoelectric element. Can be efficiently eluted into the liquid.

  In the thirteenth invention, in particular, by performing the cleaning treatment of the twelfth invention with water, the removal efficiency of components eluted from the piezoelectric ceramic powder can be increased.

  In the fourteenth aspect of the invention, in particular, when the cleaning treatment of the twelfth aspect of the invention is performed with acidic water, the component eluted from the piezoelectric ceramic powder to be removed is alkaline, so that it can be easily eluted into acidic water. And higher removal efficiency can be obtained in a shorter time than water.

  In the fifteenth aspect of the invention, in particular, by heating the cleaning liquid for performing the cleaning treatment of the twelfth to fourteenth aspects of the invention, the elution of components eluted from the piezoelectric ceramic powder can be promoted, and even higher removal efficiency is realized. can do.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a cross-sectional view of a sheet-like piezoelectric element according to the first embodiment of the present invention. In FIG. 1, a sheet-like piezoelectric element is configured by forming an electrode 2 </ b> A as a first electrode and an electrode 2 </ b> B as a second electrode on both surfaces of a sheet-like flexible pressure-sensitive body 1.

  FIG. 2 is a schematic diagram showing a partial cross section of the flexible pressure-sensitive body 1. In FIG. 2, a sheet-like flexible pressure-sensitive body 1 is composed of a piezoelectric ceramic powder 3 containing elements of Groups 1 and 2 of the periodic table and an organic polymer 4 having flexibility. The powder 3 is in a state of being uniformly dispersed with the organic polymer 4.

The compound of the piezoelectric ceramic powder 3 containing elements of Group 1 and Group 2 of the periodic table used in the present embodiment includes at least one of barium, sodium, potassium, bismuth, and lithium, specifically Includes at least one of sodium niobate, potassium niobate, lithium niobate, bismuth / sodium titanate, barium titanate, and bismuth titanate, and includes a ceramic material that exhibits piezoelectricity by poling treatment.
The sheet-like piezoelectric element according to the first embodiment is manufactured as follows. This manufacturing process is shown in FIG. First, the piezoelectric ceramic powder 3 containing the elements of Group 1 of the periodic table and Group 2 of the periodic table is immersed in a container containing water, and the components eluted from the piezoelectric ceramic powder 3 are eluted while stirring (S1). If necessary, this washing process is repeated several times and a drying process is performed to produce the piezoelectric ceramic powder 3 from which the eluted components have been removed. Next, the piezoelectric ceramic powder 3 and the flexible organic polymer 4 are uniformly mixed and dispersed in the flexible organic polymer 4 using a processing machine such as a kneader or a roll. The mixture is kneaded so as to be in a heated state (S2).

  At this time, a titanium coupling agent may be added to improve kneading. After kneading, it is processed using a processing machine such as a roll or a hot press to produce a sheet-like flexible pressure-sensitive body 1 (S3). Next, a conductive paste or conductive paint in which conductive powder and an organic polymer are mixed is applied to both surfaces of the sheet-like flexible pressure-sensitive body 1, and the conductive powder is made flexible such as rubber or thermoplastic elastomer. Electrodes 2A and 2B that are insulated from each other by any material and formation method of fusing the conductive sheet mixed and dispersed in the organic polymer having, and depositing the conductive material (S4). Thereafter, a poling process is performed by applying a DC high voltage between the electrodes 2A and 2B in the air or in a silicon oil bath in order to develop piezoelectricity (S5), and a sheet-like piezoelectric element is produced. The polling process (S5) is performed after the electrodes 2A and 2B are formed (S4). However, after the sheet-like flexible pressure-sensitive body 1 is manufactured (S3), two pseudo electrodes are used. You may go.

  The operation and action of the sheet-like piezoelectric element configured as described above will be described below.

As described above, the piezoelectric characteristics of the sheet-like piezoelectric element are manifested by applying a high direct-current voltage between the electrodes 2A and 2B and poling the flexible pressure-sensitive body 1. When a temporally changing pressure is applied to a part or the entire surface of a sheet-like piezoelectric element that exhibits piezoelectric characteristics, vibration corresponding to the acceleration generated in that part is applied between the first electrode 2A and the second electrode 2B. A voltage is induced. The pressure can be detected using this induced voltage. Sensors installed on automobile doors to prevent pinching, touch sensors installed on door handles to control unlocking, sensors installed on nursing beds, etc. to detect body movement, placed on handrails on verandas, etc. It can be used as a pressure-sensitive sensor such as a sensor that detects the intrusion of the water.

  Pressure sensors such as those mentioned above may be used outdoors or when installed in automobiles, in high-temperature steam environments during rainy seasons or in the rain in summer, and incontinence or sweat when installed in nursing beds. If it is mounted on bedding, there is a high possibility that it will be used in a high-temperature and high-humidity environment such as washing and cleaning to maintain sanitation.

  When a conventional piezoelectric element is used as a pressure-sensitive sensor in such a high temperature and high humidity environment, water vapor passes through the electrode and diffuses into the sheet-like piezoelectric element. When the temperature of the flexible pressure sensitive body is lower than the outside or when the water vapor is supersaturated on the surface of the flexible pressure sensitive body, the diffused water vapor is condensed and water is generated, and this water is generated in the flexible pressure sensitive body. Penetration causes a phenomenon in which the components eluted in the eluate in the piezoelectric ceramic powder are eluted. As a result, the capacitance of the sheet-like piezoelectric element increases and the electrical characteristics change, such as a decrease in electrical resistance. This results in inferior durability and detection when used as a pressure sensor. In addition, it is necessary to make it possible to cope with the initial change in electrical characteristics of the control circuit, which makes the circuit a complicated configuration.

  When the sheet-like piezoelectric element of the present embodiment is used in a high-temperature and high-humidity environment, water vapor passes through the electrodes 2A and 2B, and the water vapor is aggregated on the surface of the flexible pressure-sensitive body 1 to generate water. To do. However, since the sheet-like piezoelectric element of the present embodiment removes components eluted from the piezoelectric ceramic powder 3 constituting the flexible pressure-sensitive body 1, water vapor is condensed in the flexible pressure-sensitive body 1 and water is condensed. However, the elution of the eluted components from the piezoelectric ceramic powder 3 is suppressed again, and changes in electrical resistance and piezoelectric characteristics as a sheet-like piezoelectric element can be prevented. As a result, the initial electrical characteristics of the sheet-like piezoelectric element can be maintained, and excellent durability and reliability can be realized. In addition, since the initial change in electrical characteristics can be prevented, a circuit configuration for correcting the change in electrical characteristics is not required, and a circuit for detection and control can be simplified.

  In addition, the piezoelectric ceramic powder 3 containing the elements of Group 1 of the periodic table and Group 2 of the periodic table is a raw material (for example, nitrate) containing the elements of Group 1 of the periodic table and Group 2 of the periodic table so as to have a predetermined composition. , Carbonate, sulfate, etc.), and then calcined at a high temperature. At this time, the fired ceramic includes a compound having a crystal structure that exhibits piezoelectric characteristics, a compound having low crystallinity, impurities, unreacted elements and compounds, and a compound that does not exhibit piezoelectric characteristics. Exists. Although these compounds and elements have a certain amount of elution, since all the components are eluted, the components to be eluted as referred to in the present invention are all the above compounds and elements contained in the piezoelectric ceramic powder 3. It becomes a target.

  The piezoelectric characteristics of the sheet-like piezoelectric element used in the present embodiment are manifested by applying a high DC voltage between both electrodes and performing a poling process. However, the sheet-like piezoelectric element of the present embodiment is pressure sensitive. When used as a sensor, an important piezoelectric characteristic is a voltage output constant that serves as an index of the generated voltage.

A flexible pressure-sensitive body 1 constituting the sheet-like piezoelectric element of the present embodiment is composed of a composite of piezoelectric ceramic powder 3 and flexible organic polymer 4, and the relative dielectric constant ( The dielectric constant of the material (dielectric constant / vacuum dielectric constant) is several hundred to several thousands, whereas the organic polymer 4 having flexibility has several tens of dielectric constants. Since the DC voltage applied during the poling process is distributed in inverse proportion to the ratio of the dielectric constant of the piezoelectric ceramic powder 3 and the flexible organic polymer 4, the DC voltage is flexible with a low dielectric constant. A high voltage is applied to the organic polymer 4 having In other words, when the same organic polymer 4 having flexibility is used, a higher voltage is applied to the organic polymer 4 having flexibility as the dielectric constant of the piezoelectric ceramic powder 3 is higher. .

  Therefore, when the piezoelectric ceramic powder 3 of the flexible pressure-sensitive body 1 is composed of lead zirconate titanate having a relative dielectric constant of about 2000 and bismuth sodium titanate having a relative dielectric constant of about 600, the flexibility of both When a constant DC voltage is applied to the pressure body 1, a voltage higher than that of lead zirconate titanate is applied to bismuth / sodium titanate having a low relative dielectric constant, so that the poling efficiency can be increased. The constant increases. As a result, when a sheet-like piezoelectric element is used as a pressure-sensitive sensor, the output voltage of the sensor with respect to the applied pressure can be increased, so that the sensitivity can be improved and the sheet-like piezoelectric element can be improved. Since the amplification factor of the detection circuit can be lowered by increasing the sensitivity, a pressure-sensitive sensor that is strong against electrical noise can be obtained.

  The dielectric constant of the piezoelectric ceramic powder 3 used in the present invention is preferably as low as possible, but if it is 1000 or less, the voltage output constant is more than three times that when using a piezoelectric ceramic powder of lead zirconate titanate. can get. In that respect, the useful piezoelectric ceramic powder 3 includes at least one of barium, sodium, potassium, bismuth, and lithium as the compound of the piezoelectric ceramic powder 3 including elements of Group 1 and Group 2 of the Periodic Table. Specific examples include those containing at least one of sodium niobate, potassium niobate, lithium niobate, bismuth / sodium titanate, barium titanate, and bismuth titanate.

  In addition, since the piezoelectric ceramic powder 3 used in the present embodiment does not contain lead, the sheet-like piezoelectric element is disposed of, and even if it is exposed to an environment such as acid rain, there is no elution of lead and there is a possibility of environmental pollution. Absent.

  In the present embodiment, a cleaning process using water is applied as a means for removing components eluted from the piezoelectric ceramic powder 3. Thereby, the component which is easy to elute from the piezoelectric ceramic powder 3 can be eluted, without destroying the crystal structure which can express the piezoelectric characteristic of the piezoelectric ceramic powder 3.

  Further, in the washing treatment with water, elution of elution components can be promoted by heating such as boiling water or a temperature of 50 ° C. or higher. Higher removal efficiency can be achieved in a shorter time than when washing.

  Examples of the flexible organic polymer 4 used in the present embodiment include a material containing at least one of a thermoplastic elastomer and rubber. Since these flexible polymers 4 can impart excellent elasticity and flexibility to the sheet-like piezoelectric element, the sheet-like piezoelectric element has a large repulsive force and displacement amount against the applied pressure. Can be obtained, and the piezoelectric characteristics can be improved.

  In particular, as the above-mentioned thermoplastic elastomer, chlorinated polyethylene and chlorosulfonated polyethylene can increase the content of the piezoelectric ceramic powder 3 in the flexible pressure-sensitive body 1, so that the piezoelectric characteristics of the sheet-like piezoelectric element are improved. Can be improved.

The electrode 2A and the electrode 2B of the sheet-like piezoelectric element of the present embodiment can be composed of an elastic body containing at least one of a thermoplastic resin, a thermoplastic elastomer, and rubber and a conductive layer of conductive powder. In this configuration, the electrode 2A and the electrode 2B can be extended and excellent in flexibility, so that a sheet-like piezoelectric element having high bending resistance and excellent durability can be obtained. This conductive layer is a flexible pressure-sensitive material obtained by extruding an elastic material containing at least one of a thermoplastic resin, a thermoplastic elastomer, and rubber and a conductive powder using a processing machine such as an extruder. 1 is formed.

  Alternatively, the electrodes 2A and 2B may be formed of a conductive paint whose main component is a mixture of a conductive powder and an organic polymer, or a coating film of a conductive paste. In this configuration, the adhesiveness between the flexible pressure-sensitive body 1 and the electrodes 2A and 2B can be increased, and an air layer is less interposed between the electrodes 2A and 2B and the flexible pressure-sensitive body 1. Therefore, the voltage drop between the electrodes 2A and 2B and the flexible pressure-sensitive body 1 during the polling process can be suppressed, and the effective voltage of the polling process can be increased.

  Further, the electrode 2A and the electrode 2B can be formed of a vapor-deposited film of a conductive material. In this configuration, since the electrodes 2A and 2B can be formed as thin films, the excellent flexibility of the flexible pressure-sensitive body 1 can be maintained, and the piezoelectric characteristics of the flexible pressure-sensitive body 1 can be reduced. Can be prevented. This thin film is formed on the flexible pressure-sensitive body 1 by vapor deposition using an apparatus such as vacuum vapor deposition, sputtering, or CVD.

  The conductive powder and conductive material described above can achieve particularly excellent conductivity and corrosion resistance by using at least one of C, Pt, Au, Pd, Ag, Cu, Al, and Ni. .

  In addition, a conductive layer made of a conductive film in which at least one foil of C, Pt, Au, Pd, Ag, Cu, Al, and Ni is bonded to both surfaces of a polymer film such as polyethylene terephthalate and both surfaces are made conductive is provided. It may be used.

(Embodiment 2)
FIG. 4 shows a manufacturing process of the sheet-like piezoelectric element according to the second embodiment of the present invention. The difference from the manufacturing method according to the first embodiment is that the elution is contained in the piezoelectric ceramic powder 3. The cleaning process for removing the components is performed after the piezoelectric ceramic powder 3 and the flexible organic polymer 4 are kneaded, and the liquid used for the cleaning process is acidic water.

  The sheet-like piezoelectric element in the present embodiment is manufactured as follows. The manufacturing process will be described with reference to FIG. First, the piezoelectric ceramic powder 3 and the flexible organic polymer 4 were uniformly mixed and dispersed in the flexible organic polymer 4 using a processing machine such as a kneader or a roll. Kneading is performed so as to be in a state (S6). At this time, a titanium coupling agent may be added to improve kneading. Next, the kneaded piezoelectric composition is immersed in a container containing acidic water, and the components eluted from the piezoelectric ceramic powder 3 are eluted while stirring (S7). If necessary, this washing process is repeated several times to remove the eluted components, and then a drying process is performed. Next, it processes using processing machines, such as a roll or a hot press, and produces the sheet-like flexible pressure-sensitive body 1 (S8). Next, a conductive paste or conductive paint in which conductive powder and an organic polymer are mixed is applied to both surfaces of the flexible pressure-sensitive body 1, and the conductive powder has flexibility such as rubber or thermoplastic elastomer. The electrode 2A and the electrode 2B are formed by any material and forming method of fusing the conductive sheet mixed / dispersed in the organic polymer and vapor deposition of the conductive material (S9). Thereafter, a poling process is performed by applying a DC high voltage between the electrodes 2A and 2B in the air or in a silicon oil bath in order to develop the piezoelectric characteristics (S10), and a sheet-like piezoelectric element is manufactured. The polling process (S10) is performed after the electrodes 2A and 2B are formed (S9). However, after the sheet-like flexible pressure-sensitive body 1 is manufactured (S8), two pseudo electrodes are used. You may go.

In the present embodiment, the cleaning process for removing the components eluted from the piezoelectric ceramic powder 3 is performed after the piezoelectric ceramic powder 3 and the flexible organic polymer 4 are kneaded. In the kneaded piezoelectric composition, Since the piezoelectric ceramic powder 3 is contained in a large amount, the elution component can be sufficiently removed from the piezoelectric ceramic powder 3 even if it is washed in a kneaded state.
Moreover, since the component in the piezoelectric ceramic powder 3 to be removed is alkaline by using acidic water as the liquid for performing the cleaning treatment, it can be efficiently dissolved in acidic water, so that it takes less time than water. High removal efficiency can be obtained.

  Moreover, in the washing treatment with the acidic water, by heating the acidic water, elution of the components eluted from the piezoelectric ceramic powder 3 can be promoted, and higher removal efficiency is achieved in a shorter time than when not heating. can do.

(Embodiment 3)
FIG. 5 is a sectional view of a sheet-like piezoelectric element according to the third embodiment of the present invention. 5 differs from the first embodiment in that a protective layer 6 is provided to cover the flexible pressure-sensitive body 1, the electrodes 2A, and the electrodes 2B. The same members as those in the first embodiment are denoted by the same reference numerals.

As shown in FIG. 5, an electrode 2A and an electrode 2B are formed on a sheet-like flexible pressure-sensitive body 1 composed of the piezoelectric ceramic powder 3 and the flexible organic polymer 4 described in the first embodiment. The protective layer 5 is provided so as to cover the electrodes 2A and 2B and a part of the flexible pressure sensitive body 1.
FIG. 6 shows a manufacturing process of the sheet-like piezoelectric element according to the third embodiment of the present invention. The difference from the manufacturing method according to the first embodiment is that the components eluted from the piezoelectric ceramic powder 3 are as follows. The cleaning process to be removed is performed after the flexible pressure-sensitive body 1 is manufactured.

  The sheet-like piezoelectric element in the present embodiment is manufactured as follows. The manufacturing process will be described with reference to FIG. First, the piezoelectric ceramic powder 3 and the flexible organic polymer 4 were uniformly mixed and dispersed in the flexible organic polymer 4 using a processing machine such as a kneader or a roll. Kneading is performed so as to be in a state (S11). At this time, a titanium coupling agent may be added to improve kneading. Next, it processes using processing machines, such as a roll or a hot press, and produces the sheet-like flexible pressure-sensitive body 1 (S12) Next, the flexible pressure-sensitive body 1 is immersed in the container containing water. Then, the components eluted from the piezoelectric ceramic powder 3 are eluted with stirring (S13). If necessary, this washing treatment is repeated several times to remove the eluted components, followed by a drying treatment. Next, a conductive paste or conductive paint in which conductive powder and an organic polymer are mixed is applied to both surfaces of the flexible pressure-sensitive body 1, and the conductive powder has flexibility such as rubber or thermoplastic elastomer. The electrode 2A and the electrode 2B are formed by either the fusion method of the conductive sheet mixed / dispersed in the organic polymer or the deposition method of the conductive material and the forming method (S14). Furthermore, the material of the protective layer 5 is processed into a sheet shape using a processing machine such as a roll or a hot press, and the sheet-like flexible pressure-sensitive body in which the electrode 2A and the electrode 2B are formed by folding or sandwiching the sheet. 1 is formed so as to cover 1 (S15). Thereafter, a poling process is performed by applying a DC high voltage between the electrodes 2A and 2B in the air or in a silicon oil bath in order to develop the piezoelectric characteristics (S16), thereby producing a sheet-like piezoelectric element. The protective layer 5 may be provided after the polling process. The polling process (S16) is performed after the protective layer 5 is formed (S15), but after the sheet-like flexible pressure-sensitive body 1 is produced (S12), or the eluent in the piezoelectric ceramic powder 3 After performing the cleaning process (S13) for removing the components that elute in, the two pseudo electrodes may be used, or after forming the electrodes 2A and 2B (S14).

In the present embodiment, a cleaning process for removing components eluted from the piezoelectric ceramic powder 3 is performed after the piezoelectric ceramic powder 3 and the flexible organic polymer 4 are kneaded to produce the flexible pressure-sensitive body 1. However, the flexible pressure-sensitive body 1 contains a large amount of the piezoelectric ceramic powder 3 and the flexible pressure-sensitive body 1 only needs to remove components eluted from the piezoelectric ceramic powder 3 near the surface. Even if it is washed in the state of the body 1, an excellent effect can be realized.

  Further, even when water is used as the liquid for the cleaning treatment, the eluted component in the piezoelectric ceramic powder 3 to be removed is alkaline, so that it can be efficiently dissolved in water. Further, in the washing treatment with the acidic water, by heating the water, the elution of the eluted components can be promoted, and higher removal efficiency can be realized in a shorter time than the case without heating.

  Even when the sheet-like piezoelectric element having the above-described configuration is used in a high-temperature and high-humidity environment as in the first embodiment, the diffusion of water vapor reaching the surface of the flexible pressure-sensitive body 1 is present because the protective layer 5 exists. The amount can be reduced, and the amount of water to be condensed can be reduced. Therefore, since the contact between the piezoelectric ceramic powder 3 contained in the flexible pressure-sensitive body 1 and water can be reduced, it is possible to further improve the elution preventing action of the elution component from the ceramic piezoelectric powder 3. The protective layer 5 of the third embodiment is made of an organic polymer having elasticity so as not to impair the flexibility of the flexible pressure-sensitive body 1, the electrode 2A, and the electrode 2B, and in particular, a thermoplastic elastomer. Rubber material is suitable. Although the thickness of the protective layer 5 is not limited, in order not to impair the piezoelectric characteristics of the flexible pressure-sensitive body 7, it is preferable to set it as 0.2-2 mm.

Further, the protective layer 5 can prevent the sheet-like piezoelectric element from being damaged by an external mechanical force.
The protective layer 5 used in this embodiment can be applied to the sheet-like piezoelectric elements described in the first embodiment and the second embodiment, and has the same effect.

(Embodiment 4)
FIG. 7 is a partial cross-sectional view of a cable-like piezoelectric element according to the fourth embodiment of the present invention. As shown in FIG. 7, the cable-shaped piezoelectric element has a flexible pressure-sensitive body 7 formed on the outer surface of the core electrode 6 that is the first electrode, and the outer surface of the flexible pressure-sensitive body 7. Further, a flexible outer electrode 8 as a second electrode is formed, and a protective layer 9 made of an electrically insulating elastic body is further formed. The core electrode 6 and the outer electrode 8 are insulated by a pressure sensitive body 7. The core electrode 6 has a configuration in which a metal such as copper is wound around a single or a plurality of metal wires, or converging wires of many polyester fibers. The flexible pressure-sensitive body 7 is composed of a piezoelectric ceramic powder 3 containing elements of Groups 1 and 2 of the periodic table and an organic polymer 4 having flexibility, as described in the first embodiment. Compositional materials are used.

  As with the electrodes 2A and 2B in the first embodiment, the outer electrode 8 has at least one of C, Pt, Au, Pd, Ag, Cu, Al, and Ni on both surfaces of a polymer film such as polyethylene terephthalate. A conductive layer formed by winding a conductive film with a seed foil attached around a flexible flexible pressure sensor 12 in the form of a cable, and at least one conductivity of C, Pt, Au, Pd, Ag, Cu, Al, Ni A conductive layer formed by extrusion molding a flexible conductive composition prepared by kneading powder and a flexible organic polymer such as rubber or thermoplastic elastomer, and dispersing the above-mentioned conductive powder in the organic polymer The conductive film coated with the conductive paint (paste), at least one conductive material of C, Pt, Au, Pd, Ag, Cu, Al, and Ni is vacuum-deposited on the flexible pressure sensitive body 12, sputtering, Such as CVD Vapor deposition film of thin film formed by law is used. The protective layer 9 is formed by extrusion molding of the material of the protective layer 5 described in the third embodiment.

The cable-shaped piezoelectric element in the present embodiment is manufactured as follows. The manufacturing process will be described with reference to FIG. First, the piezoelectric ceramic powder 3 containing the elements of Group 1 of the periodic table and Group 2 of the periodic table described in Embodiment 1 is immersed in a container containing water, and the components eluted from the piezoelectric ceramic powder 3 are stirred. Elute (S17). If necessary, this washing process is repeated several times and a drying process is performed to produce the piezoelectric ceramic powder 3 from which the eluted components have been removed. Next, the piezoelectric ceramic powder 3 and the organic polymer 4 are kneaded using a processing machine such as a kneader or a roll so that the ceramic powder 3 is uniformly mixed and dispersed in the organic polymer 4 (S18). . At this time, a titanium coupling agent may be added to improve kneading. Next, a sheet of the piezoelectric composition is produced from the kneaded product using a roll processing machine (S19), and the piezoelectric composition sheet is processed into a pellet using a processing machine such as a pelletizer (S20). Next, the core electrode 6 is used as a core material, and the pellet-shaped piezoelectric composition is extruded using an extrusion molding machine to form a flexible pressure-sensitive body 7 layer around the core electrode 6. That is, a layer of the flexible pressure sensitive body 7 is provided around the core electrode 6 (S21). Next, the outer electrode 8 is formed using any of the materials and processing means described above (S22). Next, the protective layer 9 is formed by extrusion molding using an organic polymer such as a thermoplastic elastomer or rubber having elasticity (S23). Thereafter, a poling process is performed by applying a DC high voltage between the core electrode 6 and the outer electrode 8 in the air or in a silicon oil bath in order to develop piezoelectricity (S24), and a cable-shaped piezoelectric element is manufactured. Is done. The protective layer 9 may be provided after performing the polling process. The polling process (S24) is performed after the protective layer 9 is formed (S23). However, after forming the flexible pressure-sensitive body 7 around the core electrode 6 (S21), the core electrode 6 and the outer side are formed. The process may be performed using a pseudo electrode corresponding to the electrode 8, or may be performed after the outer electrode 8 is formed (S22).

  The cable-like piezoelectric element thus manufactured is controlled by removing the protective layer 9 and the flexible pressure-sensitive body 7 at one end and exposing the core electrode 6 and the outer electrode 8 as shown in FIG. It is connected to a circuit and used as a pressure sensitive sensor.

The operation and action of the cable-shaped piezoelectric element configured as described above will be described below. When a time-varying pressure is applied to a part or the entire surface of the cable-shaped piezoelectric element, the acceleration generated in the cable-shaped piezoelectric element in that part is between the core electrode 6 and the outer electrode 8. A corresponding oscillating voltage is induced. The pressure can be detected using this induced voltage.
When the cable-shaped piezoelectric element having the above configuration is used as a pressure-sensitive sensor in a high-temperature and high-humidity environment as in the first embodiment, since the protective layer 9 exists, the flexible pressure-sensitive body 7 of water vapor is used. The amount of diffusion of can be reduced. However, since the gap between the organic polymer three-dimensional network molecular structure of the protective layer 9 is larger than the size of one molecule of water vapor, the protective layer 9 cannot completely prevent the diffusion of water vapor. Similarly to the embodiment, the water passes through the outer electrode 6 and water is condensed on the surface of the flexible pressure-sensitive body 7 to generate water.

  In the cable-shaped piezoelectric element of the present embodiment, the components eluted from the piezoelectric ceramic powder 3 constituting the flexible pressure sensitive body 7 are removed, so that water is condensed by the flexible pressure sensitive body 7 to generate water. Even so, the elution of the elution component from the piezoelectric ceramic powder 3 is suppressed, and changes in electrical resistance and piezoelectric characteristics as a cable-like piezoelectric element can be prevented. As a result, the initial electrical characteristics of the sheet-like piezoelectric element can be maintained, and the same effects as those in the first to third embodiments can be realized.

  Further, even when a long cable-shaped piezoelectric element having a length of several kilometers or more is processed, by removing the components eluted from each particle of the piezoelectric ceramic powder 3 in advance, The above-described effect can be exhibited even at the site, and a cable-like piezoelectric element having always stable electrical characteristics can be obtained.

(Embodiment 5)
The cable-like piezoelectric element in the fifth embodiment is manufactured as follows. The manufacturing process will be described with reference to FIG. First, the piezoelectric ceramic powder 3 and the organic polymer 4 are kneaded using a processing machine such as a kneader or a roll so that the ceramic powder 3 is uniformly mixed and dispersed in the organic polymer 4 (S25). . At this time, a titanium coupling agent may be added to improve kneading. Next, the kneaded piezoelectric composition is immersed in a container containing water, and the components eluted from the piezoelectric ceramic powder 3 are eluted while stirring (S26). If necessary, this washing process is repeated several times to remove the eluted components, and then a drying process is performed. A sheet of the piezoelectric composition is produced with a roll processing machine (S27), and the piezoelectric composition sheet is processed into a pellet using a processing machine such as a pelletizer (S28). Next, using the core electrode 6 as a core material, the pellet-shaped piezoelectric composition is extruded using an extrusion molding machine, and a coating layer of the flexible pressure-sensitive body 7 is formed around the core electrode 6. That is, a layer of the flexible pressure sensitive body 7 is provided around the core electrode 6 (S29). Next, the outer electrode 8 is formed on the cable-like flexible pressure-sensitive body 7 using any of the materials and processing means described in the fourth embodiment (S30). Furthermore, the protective layer 9 is formed by extrusion molding using an organic polymer such as a thermoplastic elastomer or rubber having elasticity (S31). Thereafter, a poling process is performed by applying a DC high voltage between the core electrode 6 and the flexible outer electrode 8 in the air or in a silicone oil bath in order to develop the piezoelectric characteristics (S32), and the cable-like piezoelectricity is obtained. An element is fabricated. The protective layer 9 may be provided after performing the polling process. The polling process (S32) is performed after the protective layer 9 is formed (S31). However, after the flexible pressure-sensitive body 7 is formed around the core electrode 6 (S29), the core electrode 6 and the outer side are formed. The process may be performed using a pseudo electrode corresponding to the electrode 8, or may be performed after the outer electrode 8 is formed (S30). The cable-like piezoelectric element manufactured in this way can achieve the same operations and effects as those in the fourth embodiment.

(Embodiment 6)
The cable-like piezoelectric element according to the sixth embodiment is manufactured as follows. The manufacturing process will be described with reference to FIG. First, the piezoelectric ceramic powder 3 and the organic polymer 4 are kneaded using a processing machine such as a kneader or a roll so that the ceramic powder 3 is uniformly mixed and dispersed in the organic polymer 4 (S33). . At this time, a titanium coupling agent may be added to improve kneading. Next, a sheet of the piezoelectric composition is prepared with a roll processing machine (S34), the sheet is immersed in a container containing water, and the components eluted from the piezoelectric ceramic powder 3 are eluted while stirring (S35). If necessary, this washing process is repeated several times to remove the eluted components, and then a drying process is performed. The washed piezoelectric composition sheet is processed into a pellet using a processing machine such as a pelletizer (S36). Next, using the core electrode 6 as a core material, the pellet-shaped piezoelectric composition is extruded using an extrusion molding machine, and a coating layer of the flexible pressure-sensitive body 7 is formed around the core electrode 6. That is, a layer of the flexible pressure sensitive body 7 is provided around the core electrode 6 (S37). Next, the outer electrode 8 is formed on the cable-like flexible pressure-sensitive body 7 using any of the materials and processing means described in the fourth embodiment (S38). Furthermore, the protective layer 9 is formed by extrusion molding using an organic polymer such as a thermoplastic elastomer or rubber having elasticity (S39). Thereafter, a poling process is performed by applying a DC high voltage between the core electrode 6 and the flexible outer electrode 8 in the air or in a silicone oil bath in order to develop the piezoelectric characteristics (S40). An element is fabricated. The protective layer 9 may be provided after performing the polling process. The polling process (S40) is performed after the protective layer 9 is formed (S39). After the flexible pressure-sensitive body 7 is formed around the core electrode 6 (S37), the core electrode 6 and the outer side are formed. The process may be performed using a pseudo electrode corresponding to the electrode 8, or may be performed after the outer electrode 8 is formed (S38). The cable-like piezoelectric element manufactured in this way can achieve the same operations and effects as those in the fourth embodiment.

(Embodiment 7)
The cable-like piezoelectric element in the seventh embodiment is manufactured as follows. The manufacturing process will be described with reference to FIG. First, the piezoelectric ceramic powder 3 and the organic polymer 4 are kneaded using a processing machine such as a kneader or a roll so that the ceramic powder 3 is uniformly mixed and dispersed in the organic polymer 4 (S41). . At this time, a titanium coupling agent may be added to improve kneading. Next, a sheet of the piezoelectric composition is prepared with a roll processing machine (S42), and the piezoelectric composition sheet is processed into a pellet using a processing machine such as a pelletizer (S43). The pellet is immersed in a container containing water, and the components eluted from the piezoelectric ceramic powder 3 are eluted while stirring (S44). If necessary, this washing process is repeated several times to remove the eluted components, and then a drying process is performed. Next, the core electrode 6 is used as a core material, and the washed pellet-shaped piezoelectric composition is extruded using an extrusion molding machine to form a coating layer of the flexible pressure-sensitive body 7 around the core electrode 6. That is, a layer of the flexible pressure sensitive body 7 is provided around the core electrode 6 (S45). Next, the outer electrode 8 is formed on the cable-like flexible pressure-sensitive body 7 using any of the materials and processing means described in the fourth embodiment (S46). Furthermore, the protective layer 9 is formed by extrusion molding using an organic polymer such as a thermoplastic elastomer or rubber having elasticity (S47). Thereafter, a poling process is performed by applying a DC high voltage between the core electrode 6 and the flexible outer electrode 8 in the air or in a silicon oil bath in order to develop the piezoelectric characteristics (S48). An element is fabricated. The protective layer 9 may be provided after performing the polling process. The polling process (S48) is performed after the protective layer 9 is formed (S47). However, after forming the flexible pressure-sensitive body 7 around the core electrode 6 (S45), the core electrode 6 and the outer side are formed. The process may be performed using a pseudo electrode corresponding to the electrode 8 or may be performed after the outer electrode 8 is formed (S46). The cable-like piezoelectric element manufactured in this way can achieve the same operations and effects as those in the fourth embodiment.

(Embodiment 8)
The cable-shaped piezoelectric element in the eighth embodiment is manufactured as follows. The manufacturing process will be described with reference to FIG. First, the piezoelectric ceramic powder 3 and the organic polymer 4 are kneaded using a processing machine such as a kneader or a roll so that the ceramic powder 3 is uniformly mixed and dispersed in the organic polymer 4 (S49). . At this time, a titanium coupling agent may be added to improve kneading. Next, a sheet of the piezoelectric composition is prepared with a roll processing machine (S50), and the piezoelectric composition sheet is processed into a pellet using a processing machine such as a pelletizer (S51). Next, the core electrode 6 is used as a core material, and the washed pellet-shaped piezoelectric composition is extruded using an extrusion molding machine to form a coating layer of the flexible pressure-sensitive body 7 around the core electrode 6. That is, a layer of the flexible pressure sensitive body 7 is provided around the core electrode 6 (S52). The flexible pressure sensitive body 7 is immersed in a container containing water, and the components eluted from the piezoelectric ceramic powder 3 are eluted while stirring (S53). If necessary, this washing process is repeated several times to remove the eluted components, and then a drying process is performed. Next, the outer electrode 8 is formed on the cable-like flexible pressure-sensitive body 7 using any of the materials and processing means described in the fourth embodiment (S54). Further, the protective layer 9 is formed by extrusion molding using an organic polymer such as a thermoplastic elastomer or rubber having elasticity (S55). Thereafter, a poling process is performed by applying a DC high voltage between the core electrode 6 and the flexible outer electrode 8 in the air or in a silicone oil bath in order to develop the piezoelectric characteristics (S56). An element is fabricated. The protective layer 9 may be provided after performing the polling process. The polling process (S56) is performed after the protective layer 9 is formed (S55), but the piezoelectric pressure sensor 7 is formed after the flexible pressure-sensitive body 7 is formed around the core electrode 6 (S52) or by a cleaning process. After removing the elution component in the ceramic powder 3 (S53), it may be performed using a pseudo electrode corresponding to the core electrode 6 and the outer electrode 8, or may be performed after forming the outer electrode 8 (S54). Good. The cable-like piezoelectric element manufactured in this way can achieve the same operations and effects as those in the fourth embodiment.

  In the case of a cable-shaped piezoelectric element, the core electrode 6 needs to be wound around a roll after the flexible pressure-sensitive body 7 is covered by extrusion molding. These are operations to be performed continuously, and by providing the cleaning treatment step between the extrusion of the flexible pressure-sensitive body 7 and the winding operation of the roll, by performing the winding operation with the roll while performing the cleaning treatment, There is no need to drastically change the current manufacturing process, and productivity is not impaired.

Further, since the process for forming the flexible pressure sensitive body 7 is performed by heating, it is necessary to cool the cable-shaped flexible pressure sensitive body 7 between extrusion molding and winding with a roll. When the liquid is at a low temperature, the cleaning process can be combined with the cooling process, and this manufacturing method can ensure productivity equivalent to the current manufacturing method.

  As with the protective layer 5 of the third embodiment, the protective layer 9 of the fourth to fifth embodiments does not impair the flexibility of the flexible pressure-sensitive layer 7 and the flexible outer electrode 8. An organic polymer having elasticity is used, and thermoplastic elastomers and rubber materials are particularly suitable. Although the thickness of the protective layer 5 is not limited, in order not to impair the piezoelectric characteristics of the flexible pressure-sensitive body 7, it is preferable to set it as 0.2-2 mm.

Further, the protective layer 9 can prevent the cable-shaped piezoelectric element from being damaged by an external mechanical force.
In the fourth to eighth embodiments, the outer electrode 8 is obtained by extruding a flexible conductive composition prepared by kneading a conductive powder and an organic polymer, and the conductive powder is converted into an organic polymer. Those coated with conductive paint (paste) dispersed in and those formed with conductive materials by vacuum deposition, sputtering, CVD, etc. are protected because they have excellent adhesion to the flexible pressure sensitive body 7 The layer 9 may not be provided.

  In the fourth to eighth embodiments, water is used for the cleaning treatment. However, by using acidic water, a more excellent effect can be obtained, and further by heating the cleaning liquid, A more excellent effect can be obtained.

  In addition, referring to the result of analyzing the metal component eluted in the cleaning solution as the cleaning effect, and monitoring the saturation state of the eluted component in the cleaning solution over time, the cleaning end, etc. Various confirmation methods are possible, and the cleaning level can be appropriately specified according to the purpose of use.

  The sheet-like or cable-like piezoelectric element produced by the manufacturing method of the present invention has flexibility, so that it can be used for arrangements including bent portions and space-saving arrangements with limited mounting width. In addition, even when used in a high-temperature and high-humidity environment, it has excellent characteristics that the initial electrical characteristics can be maintained. Therefore, it is most suitable as a sensor for detecting pressure and vibration for outdoor use that requires such arrangement conditions and characteristics. Specifically, sensors are installed on devices and parts that require opening and closing, such as car sliding doors, hatchback doors, trunks, and power windows, and they are installed on car door handles to control door unlocking. Touch sensor.

In addition, body motion sensors used for nursing beds and the like need to ensure a large area detection, but the cable-like piezoelectric element of the present invention has a large area by being meandered on the bed. In addition, it can be detected, and it is an optimum configuration as a body motion sensor for a nursing bed in consideration of usage conditions such as a humid environment such as incontinence and sweat and washing for hygiene maintenance.
In addition, it can be used as a pressure-sensitive sensor such as a sensor for detecting an intrusion from the outside by placing it on a handrail of a veranda or an entrance door in an apartment or a detached house. In this case as well, the cable-shaped piezoelectric element is exposed to high-temperature and high-humidity environments because it is outdoors, but because it can maintain stable piezoelectric characteristics even in such an environment, malfunctions can be prevented and it can be used as a security sensor. can do.

  In addition, the cable-shaped piezoelectric element manufactured by the manufacturing method of the present invention can be detected in a large area by two-dimensional arrangement such as meandering on the bed, and the body of the care bed It is an optimum configuration as a motion sensor.

Sectional drawing of the sheet-like piezoelectric element in Embodiment 1 of this invention Schematic diagram showing a partial cross section of the flexible pressure-sensitive body according to Embodiment 1 of the present invention. The figure explaining the manufacturing process of the sheet-like piezoelectric element in Embodiment 1 of this invention The figure explaining the manufacturing process of the sheet-like piezoelectric element using the flexible pressure-sensitive body in Embodiment 2 of this invention. Sectional drawing of the sheet-like piezoelectric element in Embodiment 3 of this invention The figure explaining the manufacturing process of the sheet piezoelectric element in Embodiment 3 of this invention Sectional drawing of the cable-shaped piezoelectric element in Embodiment 4 of this invention The figure explaining the manufacturing process of the cable-shaped piezoelectric element in Embodiment 4 of this invention The figure explaining the manufacturing process of the cable-shaped piezoelectric element in Embodiment 5 of this invention The figure explaining the manufacturing process of the cable-shaped piezoelectric element in Embodiment 6 of this invention The figure explaining the manufacturing process of the cable-shaped piezoelectric element in Embodiment 7 of this invention The figure explaining the manufacturing process of the cable-shaped piezoelectric element in Embodiment 8 of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 7 Flexible pressure sensitive body 2A 1st electrode 2B 2nd electrode 3 Piezoelectric ceramic powder 4 Organic polymer 5, 9 Protective layer 6 Core electrode 8 External electrode

Claims (15)

A flexible pressure-sensitive body including at least a piezoelectric ceramic powder including an element of Group 1 of the periodic table and Group 2 of the periodic table and a flexible organic polymer; and a first connected to the flexible pressure-sensitive body. A component that includes an electrode and a second electrode that is connected to the flexible pressure-sensitive body and is insulated from the first electrode, and that elutes from the piezoelectric ceramic powder containing the elements of Group 1 and Group 2 of the Periodic Table Piezoelectric element with a structure that has been removed. 2. The piezoelectric element according to claim 1, further comprising a protective layer that covers the flexible pressure-sensitive body and covers at least the first electrode and the second electrode. 2. The piezoelectric element according to claim 1, further comprising a protective layer that covers the first electrode, the second electrode covers the flexible pressure sensitive body, and covers at least the second electrode. The piezoelectric element according to any one of claims 1 to 3, wherein the piezoelectric ceramic powder containing an element of Group 1 of the periodic table and Group 2 of the periodic table contains at least one of barium, sodium, potassium, bismuth, and lithium. Piezoelectric ceramic powder containing elements of Group 1 and Group 2 of the periodic table contains at least one of sodium niobate, potassium niobate, lithium niobate, bismuth / sodium titanate, barium titanate, and bismuth titanate. The piezoelectric element of any one of Claims 1-4. (A) a step of kneading a piezoelectric ceramic powder containing at least a periodic table group 1 element and a periodic table group 2 element and a flexible organic polymer; (B) at least a periodic table group 1 kneaded; Forming a flexible pressure-sensitive body from a piezoelectric ceramic powder containing a Group 2 element and a flexible organic polymer; and (C) providing a first electrode connected to the flexible pressure-sensitive body. And (D) providing a second electrode connected to the flexible pressure-sensitive body so as to be insulated from the first electrode, and (E) an element of Periodic Table Group 1 and Periodic Table Group 2 And a step of removing a component eluted from the piezoelectric ceramic powder. 2. The method of claim 1, further comprising a step of providing a protective layer covering at least the first electrode and the second electrode, wherein the first electrode and the second electrode are configured to cover the flexible pressure-sensitive body in Step C and Step D. 6. A method for producing a piezoelectric element according to 6. In Step C, the first electrode is provided so as to be covered with the flexible pressure sensitive body, and in Step D, the second electrode is provided so as to cover the flexible pressure sensitive body, and at least the first electrode and the second electrode are provided. The method for manufacturing a piezoelectric element according to claim 6, further comprising a step of providing a protective layer covering the electrode. In step E, the component which elutes from the piezoelectric ceramic powder containing the periodic table group 1 element and the periodic table group 2 element is removed, and after step E, step A is performed. The manufacturing method of the piezoelectric element of description. The component eluted from the piezoelectric ceramic powder containing the elements of Group 1 and Group 2 of the periodic table is removed after Step A in Step E of the piezoelectric element according to any one of claims 6 to 8. Production method. The component eluted from the piezoelectric ceramic powder containing the elements of Group 1 and Group 2 of the periodic table is removed after Step B in Step E of the piezoelectric element according to any one of claims 6 to 8. Production method. The piezoelectric element according to any one of claims 1 to 11 and a method for manufacturing the same, wherein a component to be eluted is removed by a cleaning treatment. The piezoelectric element according to claim 12, wherein the cleaning treatment is performed with water, and a manufacturing method thereof. The piezoelectric element according to claim 12, wherein the cleaning treatment is performed with acidic water, and a method for manufacturing the piezoelectric element. 15. The piezoelectric element according to any one of claims 12 to 14 and a method for manufacturing the same, wherein a cleaning liquid for performing a cleaning process is heated.

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