JP2008209183A - Cable-like piezoelectric element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem of a conventional cable-like piezoelectric element wherein, when it is used as a contact detector for generating voltage by contact of a person or an object to it, a part that is not used for the detection of the contact of the person or the object picks up vibration, or the like, generates an output, and causes misdetections. <P>SOLUTION: This cable-like piezoelectric element comprises an internal electrode 4, a flexible pressure-sensitive object 1, an external electrode 2, and a protective layer 3, and an insulator layer 5 is formed between the flexible pressure sensitive object 1 and external electrode 2 regarding a part of a region, and thus a part having the insulator layer becomes a dead band. By using this part of the dead band as a non-detection section, the sensitivity to the noise such as vibration is reduced, and the incorrect detection can be suppressed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cable-like piezoelectric element that has flexibility by using a flexible pressure-sensitive body formed by blending piezoelectric ceramic powder in an organic polymer and is used for contact detection.

  Conventionally, this type of flexible pressure-sensitive body is constituted by mixing and kneading a material containing a titanium coupling agent, piezoelectric ceramic powder, and at least one of chlorinated polyethylene or chlorosulfonated polyethylene. Yes (see, for example, Patent Document 1).

  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.

A sheet-shaped piezoelectric element is prepared by first forming a flexible pressure-sensitive body, in which a coupling agent, piezoelectric powder, and chlorinated polyethylene are mixed and kneaded with a roll into a sheet shape by hot pressing, and then applying a silver paste on both sides of the sheet. An electrode is formed by fusing a conductive sheet in which carbon is dispersed in a printing process or rubber, and then a poling process is performed by applying a DC voltage of several tens of kV between both electrodes in order to develop piezoelectricity. Can be obtained. When pressure is applied to part or all of this electrode surface, the flexible pressure-sensitive body in that part is distorted, resulting in a voltage being induced between both electrodes, and the presence or absence of contact is detected using this induced voltage. It can be used as a contact detector.
Japanese Patent Laid-Open No. 11-201835

  However, when the conventional piezoelectric element is used as a contact detector for detecting an intrusion into a house or the like for pinching of a slide door of an automobile or for crime prevention, vibration other than contact may be detected. In particular, the piezoelectric element portion disposed for direct connection to the circuit may detect vibration from the disposed portion that is not related to intrusion or pinching. For this reason, when using as a contact detector, in order to avoid such a false detection, there existed a subject that the arrangement | positioning method, the circuit for detection and control, and an algorithm had to be complicated.

  The present invention solves the above-described conventional problems, suppresses false detection due to vibration detection in a piezoelectric element portion that is used only for arrangement without receiving direct contact from the outside, and has a complicated installation method or a complicated An object of the present invention is to provide a cable-like piezoelectric element that does not require a simple circuit.

  In order to solve the above-described conventional problems, a cable-shaped piezoelectric element of the present invention includes a flexible pressure-sensitive body provided around an internal electrode and an external electrode provided around the flexible pressure-sensitive body. It is comprised by having the dead zone part which formed the insulator layer in a part between the said flexible pressure sensitive body and the said external electrode.

  Moreover, the contact detector using the cable-shaped piezoelectric element of the present invention is configured by using the dead zone portion of the piezoelectric element as a non-detection portion that does not detect contact.

As a result, the sensitivity of the cable-like piezoelectric element to vibration noise from the outside is suppressed at a portion where the pinch or contact due to intrusion does not occur.

  With the cable-like piezoelectric element of the present invention and its method of use, sensitivity to external vibration noise can be suppressed, false detection due to vibration can be suppressed, and excellent contact detection reliability can be realized.

  A cable-shaped piezoelectric element according to a first aspect of the present invention includes a flexible pressure-sensitive body that is provided around an internal electrode, and an external electrode that is provided around the flexible pressure-sensitive body. An insulator layer is formed in a part between a body and the external electrode. Then, when the insulator layer is formed in a part of the region, the part becomes a dead zone. As a result, sensitivity to noise such as vibration is lowered, and it is possible to suppress the occurrence of erroneous detection.

  The cable-shaped piezoelectric element according to the second invention has a configuration in which the insulating layer is formed directly on the surface of the flexible pressure sensitive body in the first invention. By forming the insulator layer directly on the surface of the flexible pressure-sensitive body, it becomes possible to form a stable insensitive body regardless of the form of the external electrode.

  The cable-like piezoelectric element of the third invention has a configuration in which the insulator layer is formed on the surface of the external electrode on the flexible pressure-sensitive body, particularly in the first or second invention. Therefore, the dead zone can be formed at an arbitrary position by the external electrode regardless of the flexible pressure sensitive body. In this way, it becomes easy to make changes in later processes, and the effect of facilitating the response to fine changes in demand can be obtained.

  In the cable-like piezoelectric element of the fourth invention, particularly in the first to third inventions, the insulator layer is formed including a crystalline organic polymer.

  Since the insulating layer is a crystalline organic polymer, a strong and highly resistant insulating layer can be obtained, and a good dead zone can be formed.

  The cable-shaped piezoelectric element according to the fifth aspect of the invention has a configuration in which the crystalline organic polymer is a polymer of a paraxylene compound, particularly in the first to fourth aspects of the invention.

  Since the crystalline organic polymer is a polymer of parylene, the insulating layer is more durable, the resistance is more uniform, and the effect of forming a good dead zone is obtained.

  A contact detector according to a sixth aspect of the invention has a configuration in which a dead band portion is used in a portion where the object to be detected does not contact, particularly using the cable-like piezoelectric element according to the first to fifth aspects of the invention.

  By using a dead zone at a portion where an object to be detected does not contact, the sensitivity to unnecessary vibration noise or the like is reduced, and an effect of suppressing false detection can be obtained.

  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 cable-shaped piezoelectric element according to the first embodiment of the present invention. Among these, (a) is a sectional view in the longitudinal direction, and (b) is a sectional view in a plane perpendicular to the longitudinal direction.

As shown in FIG. 1A, the cable-shaped piezoelectric element has a flexible pressure-sensitive body 1 formed on the outer surface of the internal electrode 4, and an external electrode 2 is formed on the outer surface of the flexible pressure-sensitive body 1. A protective layer 3 made of an elastic material is formed. At this time, in particular, it can be seen that the insulator layer 5 is formed between the flexible pressure-sensitive body 1 and the external electrode 2 on the left side along the longitudinal direction. In addition, as shown in FIG. 1B, the insulator layer 5 is formed symmetrically around the internal electrode 4 as in the other portions.

  As described above, when the insulating layer 5 is formed between the flexible pressure-sensitive body 1 and the external electrode 2, it is generated in the flexible pressure-sensitive body in response to pressure applied from the outside by contact of a person or an object. If the voltage to be taken out is taken out from the internal electrode and the external electrode, a voltage drop due to the capacitor formed by the insulator layer 5 occurs, and the measured voltage becomes small. For this reason, the part in which the insulator layer is formed is less sensitive to pressure applied by contact from the outside, and forms a good dead zone.

  By using such a part as a non-detection part such as an arrangement part that does not detect contact, it is possible to suppress a voltage caused by a vibration component that becomes noise, and to provide a highly reliable contact detector with few false detections. Is possible.

  If this insulator layer 5 is an insulator, it can use not only organic substance and an inorganic substance. For example, it can be directly formed on the flexible pressure-sensitive body 1 by applying a general resin, printing, or depositing an inorganic material such as a metal oxide, or sputtering. In the case of sputtering or vapor deposition, the insulator layer 5 can be formed at a specific location in the longitudinal direction by using an appropriate mask.

  Since the flexible pressure-sensitive body 1 is flexible and deforms, the insulator layer 5 is also preferably flexible, and thus is preferably composed of an organic material. Furthermore, in view of the strength, it is preferably a crystalline organic polymer. For example, a polymer of a paraxylene compound is preferably used. Examples of paraxylene compounds include polyparaxylene, polymonochloroparaxylene, polyhexafluoroparaxylene, and the like. The polyparaxylene compound is formed as the insulator layer 5 by polymerizing the corresponding dimer into a radical by thermal decomposition on the flexible pressure-sensitive body 1. A polymer of parexylene compound is characterized by being crystalline and high in strength, having excellent water repellency, and having a small coefficient of friction.

  Due to the excellent water repellency, the moisture resistance and water resistance of the cable-like piezoelectric element are improved, and the change in the output voltage caused by the humidity and water is suppressed, and there is an effect of avoiding false detection. In particular, when used outdoors or when mounted on a moving body such as an automobile, there is a high possibility that it will be used in a high-temperature steam environment or high-temperature and high-humidity environment due to rain in summer. The effect is great.

  In addition, when pressure is applied by an external contact object, static electricity may be generated due to friction between the external electrode 2 and the flexible pressure-sensitive body 1 (tribo effect). Static electricity due to the tribo effect is also suppressed due to the low coefficient of friction of the para-xylene compound. Since this noise can also be reduced, there is an effect that there is no false detection and high reliability is obtained.

  Hereinafter, a specific material configuration of the cable-like piezoelectric element of the present embodiment will be described.

  In FIG. 1, a flexible pressure-sensitive body 1 constituting a cable-like piezoelectric element is composed of a piezoelectric ceramic powder, a flexible organic polymer, and a titanium coupling agent. It is in a state of being uniformly dispersed in the molecule and the titanium coupling agent. At this time, the piezoelectric ceramic powder is preferably subjected to water repellent treatment. By performing the water repellent treatment, moisture resistance is improved, changes in capacitance and resistance due to moisture absorption as a piezoelectric element are suppressed, and stabilization of output as a piezoelectric element can be realized.

  The internal electrode 4 has a configuration in which a metal such as copper is wound around a plurality of metal wires or converging wires of many polyester fibers, and the external electrode 2 is made of a polymer film such as polyethylene terephthalate. A protective film 3 is formed by winding a conductive film in which at least one foil of C, Pt, Au, Pd, Ag, Cu, Al, and Ni is bonded on both sides around a cable-like flexible pressure-sensitive body 1. A thermoplastic elastomer or rubber material, which is an electrically insulating elastic body, is used so as not to impair the flexibility of the flexible pressure-sensitive body 1 and the external electrode 2.

  The cable-like piezoelectric element in the present embodiment is manufactured as follows, for example. Here, the piezoelectric ceramic powder including the step of water repellent treatment is described, but it is not always necessary.

  First, immerse and dry the piezoelectric ceramic powder by immersing it in a solution containing a water-repellent material diluted to a predetermined concentration by diluting the piezoelectric ceramic powder with a suitable solvent, or a solution of a water-repellent material heated to a melting temperature. A water-repellent-treated piezoelectric ceramic powder is formed by forming a coating layer of the water-repellent material on the piezoelectric ceramic powder by mixing with a predetermined amount of water-repellent material powder.

  Next, the water-repellent treated piezoelectric ceramic powder, the flexible organic polymer, and the titanium coupling agent are processed by using a processing machine such as a kneader or a roll, and the water-repellent treated piezoelectric ceramic powder has flexibility. After kneading so as to be uniformly mixed and dispersed in the organic polymer, a sheet-like flexible pressure-sensitive body is produced with a roll processing machine, and the sheet-like flexible pressure-sensitive body is used as a pelletizer, etc. It is processed into pellets using a processing machine.

  Next, the flexible electrode 1 is formed around the internal electrode 4 by using the internal electrode 4 as a core material and extruding the pellet-shaped flexible pressure sensor 1 using an extrusion processing machine. Thereafter, a flexible conductive film obtained by laminating a resin sheet on the surface of the metal foil is wound around the outer surface of the flexible pressure-sensitive body 1 to form the external electrode 2.

  Further, the protective layer 3 is formed by extruding the above-described electrically insulating elastic body using an extrusion molding machine. Thereafter, a poling process is performed by applying a DC high voltage between the internal electrode 4 and the external electrode 2 in the air or in a silicon oil bath in order to develop the piezoelectricity, thereby producing a cable-shaped piezoelectric element. The protective layer 3 may be provided after performing the polling process.

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

  The piezoelectricity of the cable-like piezoelectric element is manifested by applying a DC voltage between the internal electrode 4 and the external electrode 2 and poling the flexible pressure sensitive body 1. By causing the flexible pressure-sensitive body 1 to exhibit piezoelectricity, when a time-varying pressure is applied to a part or the entire surface of the cable-like piezoelectric element due to contact of a person or an object, the internal electrode 4 and the external electrode Between 2, a voltage corresponding to the acceleration generated in the cable-shaped piezoelectric element in that portion is induced. The presence or absence of contact can be detected using this induced voltage. At this time, in the portion where the insulator layer 5 is formed, the voltage to be measured is suppressed by the voltage drop due to the capacitor formed by the insulator layer 5 described above, and that portion becomes a dead zone with low sensitivity. As described in the third embodiment, this dead zone portion is used for a portion that is simply used for arrangement without detecting a contact, thereby suppressing output against noise such as vibration and avoiding false detection. It becomes possible.

  Below, the detail of a structure of each part of the cable-shaped piezoelectric element of this Embodiment is demonstrated.

In the present invention, by using a converging metal wire as the internal electrode 4, the flexible pressure-sensitive body 1 provided around the internal electrode 4 enters between the metal wires of the internal electrode 4. 4
And the flexible pressure-sensitive body 1 can reduce the interposition of the air layer, so that the voltage drop between the internal electrode 4 and the flexible pressure-sensitive body 1 during the poling process can be suppressed, and the poling process. The effective voltage can be increased.

  Moreover, when using what wound the metal wire or metal foil around the converging line of many polyester fibers as the internal electrode 4, the flexible pressure-sensitive body 1 provided around the internal electrode 4 is the converging line of the polyester fiber. Since it enters between the wound metal wire or the metal foil, the adhesion between the internal electrode 4 and the flexible pressure-sensitive body 1 is improved, which is possible in addition to the action and effect of the internal electrode 4 in which a plurality of metal wires are converged. The tensile strength of the flexible pressure sensitive body 1 can be increased.

  Further, by using a material containing at least one of C, Pt, Au, Pd, Ag, Cu, Al, and Ni as the material of the metal wire or metal foil used for the internal electrode 4, particularly excellent conductivity and corrosion resistance. Can be realized.

  Examples of the flexible organic polymer used in the present invention include materials containing at least one of a thermoplastic elastomer and rubber. These flexible polymers can provide excellent elasticity and flexibility to the cable-like piezoelectric element, so that a large repulsive force and displacement can be obtained with respect to the applied pressure, 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 in the flexible pressure-sensitive body 1, so that the piezoelectric characteristics of the cable-like piezoelectric element can be improved. Can do.

  The titanium coupling agent used in the present invention covers the water-repellently treated piezoelectric ceramic powder, and has a hydrophobic side chain organic functional group on the outside, so that it can become familiar with wet organic polymers (wetting). Property), lowering the overall viscosity, improving processability, flexibility, and dispersibility of the water-repellent treated piezoelectric ceramic powder, the expression of piezoelectricity can be remarkably improved.

  Especially when isopropoxy triisostearoyl titanate, isopropoxy tris (dioctyl pyrophosphate) titanate as titanium coupling agent, and chlorinated polyethylene or chlorosulfonated polyethylene as flexible organic polymer are used, piezoelectric ceramics Since the familiarity with the powder is further improved, the kneading process time can be shortened, the piezoelectric characteristics can be improved, the piezoelectric characteristics can be stabilized and the flexibility can be improved, and it can be easily molded into any shape. Can do.

  The reason why the above-mentioned familiarity is good is that the SP value (solubility parameter) of isopropoxytriisostearoyl titanate, isopropoxytris (dioctyl pyrophosphate) titanate has a value of 8 to 9, while chlorinated polyethylene, The SP value of chlorosulfonated polyethylene is 9 to 9.5, which is considered to have a similar SP value.

  In addition, the protective layer 3 used in the present invention can improve the adhesion between the flexible pressure-sensitive body 1 and the external electrode 2 by using a material containing at least one of an electrically insulating thermoplastic elastomer and rubber. Therefore, the sensitivity of the piezoelectric element can be improved, and the cable-shaped piezoelectric element can be prevented from being damaged by an external mechanical force.

The external electrode 2 can be composed of an elastic body including at least one of a thermoplastic resin, a thermoplastic elastomer, and rubber and a conductive layer of conductive powder. In this configuration, since the external electrode 2 can be an extended outer electrode having excellent flexibility, a cable-shaped 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. Formed.

  Further, the external electrode 2 can also be constituted by a coating film or a printing film of a conductive paint or conductive paste whose main component is a mixture of conductive powder and organic polymer. In this configuration, the adhesion between the flexible pressure-sensitive body 1 and the external electrode 2 can be increased, and the interposition of an air layer between the external electrode 2 and the flexible pressure-sensitive body 1 can be reduced. The voltage drop between the internal electrode 4 and the flexible pressure sensitive body 1 during the treatment can be suppressed, and the effective voltage of the polling treatment can be increased.

  Further, the external electrode 2 can be composed of a deposited film of a conductive material. In this configuration, since the external electrode 2 can be formed of a thin film, the excellent flexibility of the flexible pressure sensitive body 1 can be maintained, and the deterioration of the piezoelectric characteristics of the flexible pressure sensitive body 1 can be prevented. be able to. This thin film is formed by vapor deposition on a flexible pressure sensitive body 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. .

  Further, since the external electrode 2 described in the second embodiment has excellent adhesion to the flexible pressure-sensitive body 1, a protective layer is provided around the external electrode 2 described in the first embodiment. Although it can be used as a cable-like piezoelectric element without forming 3, protective layer 3 may be formed.

  The cable-shaped piezoelectric element is flexible and has a cable shape, so that it can be used for arrangements including bent portions and space-saving arrangements with limited mounting widths, and high temperature and high Even when used in a humid environment, it has excellent characteristics capable of maintaining the initial electrical characteristics, piezoelectric characteristics, and mechanical strength. Therefore, it is suitable for use as a piezoelectric element for contact detection for outdoor use that requires such arrangement conditions and characteristics, particularly as a piezoelectric element for detecting pinching by being installed in a car or the like.

(Embodiment 2)
The cable-like piezoelectric element of the present embodiment has the same configuration as that of FIG. 1 of the first embodiment, but in this embodiment, the insulator layer 5 is in contact with the flexible pressure-sensitive body 1 side of the external electrode 3. It is characterized by being formed on the side. In the following description, the same members as those in the first embodiment are denoted by the same reference numerals. Further, the material of each part is not described in detail, but the material described in the first embodiment is used.

  FIG. 2 shows a configuration of the tape-like external electrode 2 used in the cable-like piezoelectric element 6 of the present embodiment. Among these, (a) is a sectional view in the longitudinal direction, and (b) is a sectional view in a plane perpendicular to the longitudinal direction.

  As shown in FIG. 2A, the external electrode 2 is configured by forming metal layers 9 on both sides of the resin sheet 8. Moreover, the insulator layer 5 is formed in a partial region in the longitudinal direction of one surface.

  The external electrode 2 is formed by continuously winding the insulating layer 5 so as to be in contact with the flexible pressure-sensitive body 1, and a cable-like piezoelectric element as shown in FIG. 1 can be configured. In this case, in FIG. 1, the overlap and boundary of the external electrodes when the tape-like external electrode 2 is wound are not shown.

  In FIG. 2, the insulator layer 5 is formed in a partial region on one surface of the metal layer 9. However, the insulator layer 5 is formed on both surfaces or the entire surface of the metal layer 9 in the partial region. You can also. Specifically, it can be formed by a dry process such as resin coating, printing, organic or inorganic vapor deposition, or sputtering.

  Since the insulating layer 5 is directly formed on the external electrode 3 as shown in FIG. 1, a dead zone is formed in an arbitrary region by forming the external electrode 3 after the flexible pressure-sensitive body 1 is formed by extrusion molding or the like. It becomes possible to form. The operation of forming the dead zone 7 by the insulator layer 5 is as described in the first embodiment. In this way, the degree of freedom in design is increased, and the effect of facilitating the response to minute changes in demand can be obtained.

(Embodiment 3)
In this embodiment, a contact detector using the cable-like piezoelectric element of Embodiment 1 or 2 will be described. In the following description, the same reference numerals are used for the same members as those in the first embodiment. In addition, regarding the material of each part, the materials described in the first embodiment are used.

  FIG. 3 is a diagram showing the configuration of the contact detector of the present embodiment. Most of the cable-shaped piezoelectric element 6 is housed and fixed in the contact detection support fixing portion 10. The cable-like piezoelectric element 6 is connected to the circuit 11 by removing the protective layer 3 and the flexible pressure-sensitive body 1 at one end and exposing the internal electrode 4 and the external electrode 2, and is used as a contact detector.

  At this time, the non-detecting portion 13 that comes out of the contact detection supporting and fixing portion 10 and reaches the circuit 11 is constituted by the dead zone 7 of the cable-like piezoelectric element 6. In the dead zone 7, as in FIG. 1, an insulator layer 5 is formed between the flexible pressure sensitive body 1 and the external electrode 2.

  Next, the operation of the contact detector according to the present embodiment will be described.

  When a person or object comes into contact with the contact detection support fixing portion 10 from the outside, the contact detection support fixing portion 10 is deformed, and pressure is transmitted to the cable-like piezoelectric element 6 due to the deformation. As a result, electric charges are generated in the flexible pressure-sensitive body 1, and a potential difference is generated between the internal electrode 4 and the external electrode 2. This is detected by the circuit 11, and it is determined that contact has occurred when a voltage exceeding a certain threshold is generated.

  The non-detecting portion 13 of the cable-like piezoelectric element 6 that is not housed in the contact detection support fixing portion 10 does not directly detect contact of a person or an object, but is disposed on a disposed base, for example, a sliding door of an automobile. In this case, vibrations from the main body of the automobile are directly transmitted to the non-detecting portion 13 as well. Since the transmitted vibration is larger than that of the cable-shaped piezoelectric element 6 housed in the contact-detecting support / fixing portion 10, conventionally, a voltage equal to or higher than a threshold value is applied to the non-detection portion of the cable-shaped piezoelectric element 6 due to the vibration. May occur and false detection may occur.

  However, in the present embodiment, the dead zone 7 is used for the non-detecting portion 13 where the noise such as vibration is large, and the dead zone 7 has low sensitivity to pressure application due to the formation of the insulating layer 5. For this reason, the voltage more than a threshold value does not generate | occur | produce by weak pressure stimuli, such as a vibration. In this way, output noise caused by vibration or the like is suppressed, and contact detection without erroneous detection becomes possible.

The contact detection support and fixing portion 10 of the present embodiment accommodates the cable-like piezoelectric element 6 and fixes it to various curved surfaces, and also deforms the pressure caused by the contact of people and objects from the outside. In order to transmit to the cable-shaped piezoelectric element 6, it is preferable to have flexibility. For this reason, thermoplastic elastomers and rubber materials are preferably used. In addition, the support fixing part 1 for contact detection
For example, the cable-shaped piezoelectric element 6 is accommodated in 0 by inserting the cable-shaped piezoelectric element 6 into a hole formed in the contact detection support fixing portion 10.

  In the contact detector 11 of the present invention, since the cable-like piezoelectric element 6 has flexibility and the shape is cable-like, the contact detection support fixing portion 10 is also made of a flexible material. Because it can be used suitably, it can be used for installation including bent parts and space-saving installation with limited mounting width. It can be installed on intrusion detectors for outdoor use, especially in cars, etc. It is suitable for use as a contact detection sensor that prevents pinching with objects.

  As described above, when the cable-shaped piezoelectric element according to the present invention is used for contact detection, the dead zone is used in the non-detection part used for the arrangement that connects the contact detection part and the circuit. The effect of suppressing noise such as vibration and avoiding false detection can be obtained. Therefore, various detectors that detect contact, for example, a pinch sensor that detects the touch of a person or an object to the door or window of an automobile and prevents pinching, and installed on a balcony, etc., to the balcony of an intruder from the outside It can be applied to a wide range of uses such as a security sensor that detects the contact of the sensor in a place with a lot of vibration.

(A) Longitudinal cross-sectional view of the cable-like piezoelectric element according to Embodiment 1 of the present invention (b) Cross-sectional view of the cable-like piezoelectric element taken along the line AA (A) Longitudinal cross-sectional view of an external electrode on which an insulator layer is formed in Embodiment 2 of the present invention (b) Cross-sectional view of the external electrode taken along line BB The figure which showed the structure of the contact detector using the cable-shaped piezoelectric element in Embodiment 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Flexible pressure sensitive body 2 External electrode 3 Protective layer 4 Internal electrode 5 Insulator layer 6 Cable-shaped piezoelectric element 7 Dead body (cable-shaped piezoelectric element)
8 Resin sheet 9 Metal layer 10 Support fixing part for contact detection 11 Circuit 12 Contact detector 13 Non-detection part

Claims (6)

A part between the flexible pressure sensitive body and the external electrode, including a flexible pressure sensitive body provided around the internal electrode and an external electrode provided around the flexible pressure sensitive body. A cable-like piezoelectric element having a dead zone having an insulator layer formed on the surface thereof. The cable-like piezoelectric element according to claim 1, wherein the insulating layer is formed directly on the surface of the flexible pressure sensitive body. The cable-like piezoelectric element according to claim 1 or 2, wherein the insulator layer is formed on a surface of the external electrode on the flexible pressure sensitive body side. The cable-shaped piezoelectric element according to any one of claims 1 to 3, wherein the insulator layer is formed including a crystalline organic polymer. The cable-like piezoelectric element according to claim 1, wherein the crystalline organic polymer is a para-xylene compound polymer. The contact detector using the cable-like piezoelectric element according to claim 1, wherein a dead zone is used for a non-detecting portion that does not detect contact.

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