JP2007292575A - Pressure detection element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem, wherein the response voltage when pressure is applied from the outside drops results in the deterioration of accuracy in pressure detection in the conventional flexible pressure detection element, since flexible pressure sensing element will harden, especially at low temperatures. <P>SOLUTION: An electrode 12, having flexibility and provided with a flexibility enhanced part 15 inside, is formed outside a flexible pressure sensing element 11. Since the flexible electrode 12 easily sinks downward due to this, when pressure Po is applied downward from the outside, the flexible pressure sensing element 11 is deflected significantly downward. In this way by accelerating deflection mode at deformation and increasing the size of the deflection area the response voltage can be restrained from lowering, especially at low temperatures. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a pressure detection element that uses a flexible pressure-sensitive body and detects pressure applied from the outside.

  Conventionally, there is such a pressure detection element as shown in FIG. As shown in the cross-sectional view of FIG. 17, the electrode 2 is formed on the upper and lower sides of the flexible pressure-sensitive body 1, and the protective layer 3 covers the surface. In the pressure detection element shown in FIG. 17, the direction of remanent polarization in the flexible pressure-sensitive body 1 is not shown. Usually, in order to form a polarization by applying a high voltage between the electrodes 2, Residual polarization is formed in the direction perpendicular to the surface.

  As the flexible pressure-sensitive body 1, a composite in which a piezoelectric ceramic powder such as lead titanate or lead zirconate titanate is added to synthetic rubber or synthetic resin is used. The electrode 2 is configured by bonding a metal foil such as copper, aluminum, or gold to the flexible pressure-sensitive body 1 with an adhesive or the like, or depositing the above metal.

  When a dynamic pressure is applied to the pressure detection element from the outside, the flexible pressure-sensitive body 1 is distorted with acceleration, and at the same time, a voltage is generated due to the piezoelectric effect. A dynamic pressure is detected by measuring this voltage as a response voltage via the two electrodes 2.

  Moreover, there exists a cable-shaped thing as shown in FIG. 18 (a), (b) (for example, refer patent document 1) as a conventionally known pressure detection element. 18A shows a cross section in the longitudinal direction of the cable, and FIG. 18B shows a cross section taken along the line AA in FIG. 18A. Specifically, the inner electrode 4 is formed at the center, the flexible pressure-sensitive body 1 is formed around the inner electrode 4, the outer electrode 5 is formed outside the inner electrode 4, and the protective layer 3 is finally formed. 18 (a) and 18 (b) do not show the direction of remanent polarization in the flexible pressure-sensitive body 1, but normally a high voltage is applied between the internal electrode 4 and the external electrode 5 to form polarization. Therefore, residual polarization is radially formed from the internal electrode 4 to the external electrode 5.

  For the flexible pressure-sensitive body 1 in FIGS. 18A and 18B, a composite similar to the layered flexible pressure-sensitive body in FIG. 17 is used. For the internal electrode 4, a linear conductive material in which a conductor such as metal is linear is used. Further, the external electrode 5 is formed by applying a conductive paint such as a silver-based rubber paint on the surface of the flexible pressure-sensitive body 1. The pressure is detected by measuring the response voltage generated due to the distortion of the flexible pressure-sensitive body 1 accompanied by the acceleration due to the application of dynamic pressure, as in the case of the pressure detection element using the sheet-like flexible pressure-sensitive body. Is done.

  Here, the definition regarding the dynamic pressure used above and also a static pressure is demonstrated. The dynamic pressure is a pressure that is not balanced with a stress corresponding to the dynamic pressure, and as a result, an acceleration is generated in an object to which the dynamic pressure is applied.

On the other hand, the static pressure is a pressure that perfectly balances the stress corresponding to the static pressure, and as a result does not cause acceleration in an object to which the static pressure is applied. For this reason, static pressure is not detected by the method using the flexible pressure sensitive body. Unless otherwise specified, the pressure used below means the above dynamic pressure that can be detected by a pressure detecting element using a flexible pressure sensitive body.
JP-A-62-230071

  However, the conventional pressure detecting element has a large temperature dependency of a response voltage generated by an external pressure, and has a problem that the voltage is lowered particularly at a low temperature and pressure detection accuracy is lowered.

  In view of the above-described conventional problems, the problem to be solved by the present invention is to provide a pressure detection element that reduces the temperature dependence of the response voltage generated by external pressure application and avoids a decrease in pressure detection accuracy. It is in.

  In order to solve the above-described problems, a pressure detection element of the present invention includes a flexible pressure-sensitive body having remanent polarization and a plurality of electrodes for extracting signals from the flexible pressure-sensitive body, and the electrodes have increased flexibility. It is set as the structure which has a part. Thereby, when an electrode has a flexibility increase part, when a pressure is applied from the outside, a flexible pressure sensitive body will bend greatly because of a deformation | transformation of the electrode to which the softness | flexibility was provided.

  As described above, in the flexible pressure-sensitive body, when the deformation in the bending mode is increased, a portion where distortion occurs is increased, and the response voltage is increased. For this reason, especially at a low temperature at which the flexible pressure-sensitive body is hard and distortion caused by the compression mode is small, a decrease in response voltage is suppressed, and a decrease in pressure detection accuracy is suppressed.

  In the pressure detection element of the present invention, the elastic modulus of the electrode portion in the direction in which external pressure is applied is made larger than that of the electrode portion in the direction in which no pressure is applied.

  As a result, the elastic modulus of the electrode portion in the direction in which external pressure is applied is larger than the elastic modulus of the electrode portion in the direction in which no pressure is applied. Mode deformation is unlikely to occur, and conversely, deformation of the bending mode is likely to occur. In particular, at a low temperature, the flexible pressure-sensitive body becomes hard and distortion due to deformation in the compression mode is suppressed, but the deformation in the bending mode increases because the bending width increases by becoming hard, so the corresponding response voltage increases. A decrease in overall response voltage is suppressed, and a decrease in pressure detection accuracy is suppressed.

In the pressure detection element of the present invention, even in an environment with a large temperature change, a change in response voltage, particularly a decrease at a low temperature is suppressed, and pressure detection can be performed with high accuracy.

  A pressure detection element according to a first aspect of the present invention includes a flexible pressure-sensitive body having remanent polarization and a plurality of electrodes that extract signals from the flexible pressure-sensitive body, and the electrodes have a flexibility increasing portion. Is.

  As a result, since the electrode is more flexible due to the flexibility increasing portion, when the pressure is applied from the outside, the deformation in the bending mode increases and the deformation of the portion where the distortion occurs increases, thereby increasing the response voltage. Become. In particular, at a low temperature at which the flexible pressure-sensitive body becomes hard and distortion due to deformation in the compression mode becomes small, a decrease in response voltage is suppressed, and a decrease in pressure detection accuracy is suppressed.

  According to a second invention, in the first invention, the flexibility increasing portion is made of a foam, and the electrode having the flexibility increasing portion formed of the foam achieves excellent flexibility, and the pressure detection element When pressure is applied from the outside, the degree to which the flexible pressure sensitive body bends increases. Therefore, since the deformation in the bending mode is promoted, a decrease in the response voltage especially at a low temperature is suppressed, and the pressure can be detected with high accuracy even when the environmental temperature changes.

  According to a third invention, in the first or second invention, the flexibility increasing portion is formed on the electrode opposite to the side to which the external force of the flexible pressure sensitive body is applied, and the flexibility increasing portion is the side to which the external force is applied. The electrode on the opposite side, for example, the lower electrode located on the lower side, so that the flexibility of the lower electrode on the opposite side to the side to which external force is applied even when compressed by external pressure Therefore, deformation of the bending mode toward the lower portion of the flexible pressure sensitive body preferentially proceeds.

  Accordingly, a decrease in response voltage at a low temperature is further suppressed, and highly accurate pressure detection is possible even when the environmental temperature changes.

  A fourth invention includes a flexible pressure-sensitive body having remanent polarization and a plurality of electrodes for extracting signals from the flexible pressure-sensitive body, and the electrodes are portions in a direction in which external pressure is applied, for example, in the vertical direction This is a pressure detection element in which the elastic modulus of this part is larger than that of a part in a direction where no external pressure is applied, for example, a part in the horizontal direction.

  As a result, the elastic modulus of the vertical electrode portion is larger than the elastic modulus of the horizontal electrode portion, so that when the external pressure is applied in the vertical direction, the vertical compression mode is deformed. Since the deformation is mainly suppressed and the deformation in the bending mode is mainly performed, the decrease in the response voltage at a low temperature is further suppressed, and the pressure can be detected with high accuracy even when the environmental temperature changes.

  According to a fifth aspect of the present invention, in the fourth aspect, the thickness of the portion in the direction in which the pressure from the outside of the electrode is applied, for example, the vertical portion is set to be larger than the portion in the direction in which no pressure from the outside is applied, for example, the horizontal portion. Thinned.

  Thereby, by making the thickness of the vertical part of the electrode thinner than the thickness of the horizontal part, when pressure is applied from the outside in the vertical direction, deformation of the compression mode in the vertical direction is suppressed, Since deformation in the bending mode is mainly performed, a decrease in response voltage at a low temperature is further suppressed, and high-precision pressure detection is possible even when the environmental temperature changes.

  According to a sixth invention, in the fourth or fifth invention, since the electrode is a pressure detection element having a compression suppressing portion in a portion in the direction in which an external force is applied, for example, a vertical portion, the electrode is formed in the vertical direction. By having a compression suppression part in the part, deformation of the compression mode in the vertical direction is suppressed, deformation of the bending mode is mainly performed, a decrease in response voltage at low temperatures is further suppressed, and even if the environmental temperature changes, the accuracy can be improved. High pressure detection is possible.

  A seventh invention includes a flexible pressure-sensitive body having remanent polarization and a plurality of electrodes for extracting signals of the flexible pressure-sensitive body, and the flexible pressure-sensitive body is a portion in a direction in which an external force is applied, for example, vertical This is a pressure detecting element in which the elastic modulus of the directional portion is larger than that of a portion where no external force is applied, eg, a horizontal portion.

  As a result, the elastic part of the flexible pressure sensor has a higher modulus of elasticity in the vertical direction than in the horizontal direction, so that deformation of the compression mode in the vertical direction is suppressed when pressure is applied from the outside in the vertical direction. Since the deformation is mainly in the bending mode, the decrease in the response voltage at a low temperature is further suppressed, and the pressure can be detected with high accuracy even when the environmental temperature changes.

  In an eighth aspect based on the seventh aspect, the thickness of the flexible pressure sensitive body in the direction in which the external force is applied, for example, the vertical portion is made thinner than the portion in the direction in which no external force is applied, for example, the horizontal portion. It is a pressure detection element.

As a result, the thickness of the vertical portion of the flexible pressure sensitive body is made thinner than the thickness of the horizontal portion, so that when the pressure is applied from the outside in the vertical direction, the deformation of the vertical compression mode is changed. Is suppressed, and the decrease in the response voltage at a low temperature is further suppressed, and the pressure can be detected with high accuracy even when the environmental temperature changes.

  According to a ninth invention, in any one of the first to eighth inventions, the electrode has a bending width expanding portion, and the electrode having the bending width expanding portion is applied when pressure is applied from the outside in the vertical direction. In addition, the entire width of the electrode is pulled by the bending width expanding portion, so that the bending width is widened and the deformation in the bending mode is further promoted. Accordingly, a decrease in response voltage at a low temperature is further suppressed, and highly accurate pressure detection is possible even when the environmental temperature changes.

  According to a tenth aspect of the invention, in any one of the first to ninth aspects, the flexible pressure-sensitive body has a bending width expanding portion, and the flexible pressure-sensitive body having the bending width expanding portion is externally provided. When the pressure is applied, for example, in the vertical direction, the flexible pressure-sensitive body is pulled by the flexible width-expanding portion, so that the flexible pressure-sensitive body is widened and the deformation of the flexible mode is further promoted. Accordingly, a decrease in response voltage at a low temperature is further suppressed, and highly accurate pressure detection is possible even when the environmental temperature changes.

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. Further, in the description of the present embodiment, parts having the same configuration and the same operational effects are denoted by the same reference numerals, and redundant description will not be given.
(Embodiment 1)
Prior to the description of the specific embodiment, the experimental results that led to the present invention will be described with reference to FIGS. FIG. 1A is a cross-sectional view showing a state in which a rigid body is placed under the pressure detection element and pressure is applied with an indenter from above, and FIG. 1B is a top view of a sponge placed under the pressure detection element. It is sectional drawing which showed a mode that pressure was applied with an indenter. FIG. 1C qualitatively shows the temperature dependence of the response voltage corresponding to FIG. 1A and FIG. 1B, and describes the main deformation modes at that time. is there.

  In FIG. 1A, since the pressure detection element 14 is placed on a rigid body, the pressure detection element 14 hardly bends, and distortion occurs in the flexible pressure-sensitive body 11 due to deformation in the compression mode. On the other hand, in FIG. 1B, since the sponge is placed under the pressure detection element 14, the flexible pressure sensitive body 11 sinks greatly in the sponge, and the deformation of the compression mode generated in the center portion is performed. In addition to this distortion, distortion due to deformation of the bending mode occurs in a wider range.

  The response voltage V corresponding to FIG. 1A greatly decreases at a low temperature as in the compression mode (a) shown in FIG. This is presumably because the flexible pressure-sensitive body 11 becomes hard at low temperatures, and distortion due to deformation in the compression mode hardly occurs in the flexible pressure-sensitive body 11. In contrast, in the case of FIG. 1B, the inventors have shown that the decrease in the response voltage V at low temperatures is suppressed as in (b) compression + deflection mode shown in FIG. 1C. I found it. In the figure, 11 is a flexible pressure-sensitive body, 12 is an electrode, and a response voltage generated by the flexible pressure-sensitive body 11 due to deformation due to deformation is taken out. Reference numeral 13 denotes an external protective layer.

  This is because, when the flexible pressure-sensitive body 11 becomes hard at low temperatures, distortion due to deformation in the compression mode is suppressed, but conversely, distortion due to deformation in the bending mode causes bending due to the flexible pressure-sensitive body 11 becoming hard. This is presumably because the region distorted by deformation increases and the response voltage increases. Therefore, by suppressing the deformation in the compression mode and promoting the deformation in the bending mode, it is possible to suppress a decrease in the response voltage due to the curing of the flexible pressure sensitive body 11 at a low temperature. This is the main significance of the present invention.

  In the following, a specific configuration of the present invention will be derived according to the above significance. The description will be divided into (1) a configuration that promotes deformation in the bending mode and (2) a configuration that suppresses deformation in the compression mode. In this embodiment, (1) a configuration that promotes deformation in the bending mode will be described. I do.

  2 (a) and 2 (b) are diagrams illustrating the promotion of deformation in the bending mode by the cross section of the flexible pressure sensitive body 11 and the electrode 12, and in FIG. 2 (a), the amount of bending is expressed as the bending width. L1 and a downward bending depth L2 are shown. There are two patterns of deformation promotion in the bending mode. One is a case where the deflection width L1 is expanded to L1 + α as represented by the change from FIG. 2A to FIG. The other is a case where the downward deflection depth L2 increases to L2 + β as represented by the change from FIG. 2 (a) to FIG. 2 (c).

  In the present embodiment, a configuration that realizes the latter of the two cases will be described with reference to FIGS. 3A and 3B to FIGS. 5A and 5B. First, the configuration of the present embodiment will be described with reference to FIGS. 3A and 3B are cross-sectional views of a linear pressure detecting element 14 having a predetermined length having the layered structure of the present embodiment. FIG. 3A is a cross-sectional view in the longitudinal direction. (B) represents the cross section in the BB line position of Fig.3 (a).

  The flexible pressure sensitive body 11 is sandwiched between electrodes 12 from above and below, the electrode 12 is protected by an external protective layer 13, and the deformation of the flexible pressure sensitive body 11 of the pressure detecting element 14 is applied by applying an external pressure Po. A signal generated by distortion due to the above is taken out as a response voltage. The upper and lower electrodes 12 in the vertical direction, which is the portion in the direction in which the pressure Po from the outside is applied, are embedded with a flexible increase portion 15 having a narrow flexibility along the entire longitudinal direction. Is formed.

  As described above, the upper and lower electrodes 12 of the pressure detecting element 14 are easily deformed because the flexible increased flexibility portion 15 is formed. The flexible pressure-sensitive body 11 can also be applied downward (applying pressure Po from the outside) as shown in FIG. 2C when the pressure Po from the outside is applied due to the ease of deformation of the electrode 12. The bending L2 increases in the direction opposite to the direction), and the deformation in the bending mode is promoted.

  Therefore, even when the flexible pressure-sensitive body 11 is cured at a low temperature, the rate of deformation in the bending mode is increased, so that an effect of suppressing a decrease in response voltage is obtained, and compression + deflection in FIG. As in the case of mode (b), an effect of suppressing a decrease in response voltage is obtained.

  Such a pressure detection element can detect pressure with high accuracy even when the ambient temperature used changes, so it is particularly suitable for applications that are used outdoors or in environments close to the outdoors where the temperature changes greatly. It is done. For example, it is particularly suitable for security purposes, such as installation outside a house such as a balcony or fence to detect intruders. Further, it is also suitably used for the purpose of detecting the pinching of a person or an object into an automobile door or a building door.

  In the following, another configuration of the pressure detection element according to the present embodiment will be described. However, where the same configuration and the same effect are obtained, the same reference numerals are assigned and detailed description is omitted, and only different portions are described. To do.

Next, a different configuration of the pressure detection element in the present embodiment will be described with reference to FIGS. 4 (a) and 4 (b). 4 (a) and 4 (b) are cross-sectional views of a linear pressure sensing element having a predetermined length and having a layered structure in another configuration of the present embodiment, and FIG. 4 (a) is a cross-section in the longitudinal direction. FIG. 4B shows a cross section taken along the line CC in FIG. Similar to the pressure detection element 14 shown in FIGS. 3A and 3B, the electrode 12 is formed by embedding a flexible increase portion 15 having a narrow flexibility along the entire longitudinal direction. However, the difference is that the flexibility increasing portion 15 is formed only on the lower electrode 12 which is the portion opposite to the side to which the external pressure Po is applied.

  In the present specification, the lower part and the upper part define the direction in which external pressure is applied as the upper part and the opposite direction as the lower part.

  As described above, since the flexible increased flexibility portion 15 is formed only on the lower electrode 12, the bending width L1 can be increased as shown in FIG. This is because, when the flexible increaseable portion 15 is formed also on the upper portion, the upper electrode 12 which is a portion to which the external pressure Po is applied is selectively distorted, and the flexible pressure sensitive body is in contact therewith. 11, force is applied selectively, but when the increased flexibility portion 15 is not formed on the upper portion and the upper electrode 12 becomes relatively hard, a wider portion of the upper electrode 12 is distorted, and a corresponding wide region This is because a force is applied to the flexible pressure-sensitive body 11 to bend downward. As a result, an effect of suppressing a decrease in response voltage at a low temperature can be obtained as in the pressure detecting element shown in FIG.

  5 (a) and 5 (b) are cross-sectional views of the cable-shaped pressure detection element in the present embodiment, in which FIG. 5 (a) is a longitudinal cross section, and FIG. 5 (b) is a cross-sectional view of FIG. 5 (a). The cross section in the DD line position is represented. 3A and 3B, the flexibility increasing portion 15 integrated with the electrode is formed in the same manner as the pressure detecting element 14 shown in FIGS. 3A and 3B, except that the electrode is the center of the flexible pressure-sensitive body 11. Is formed as an external electrode 17 provided on the outer periphery of the flexible pressure-sensitive body 11 and has a cable-like structure, and the flexibility increasing portion 15 is formed on the entire outer periphery of the external electrode 17. It is a point that is formed.

  The external electrode 17 has a bending width L1 (see FIG. 3) when an external pressure Po is applied in the same manner as the pressure detection element 14 shown in FIGS. 2 (b)) mode deformation is promoted. Therefore, even when the flexible pressure sensitive body 11 is cured at a low temperature, an effect of suppressing a decrease in response voltage can be obtained.

  Furthermore, since it can be manufactured by a continuous extrusion process by having a cable-like configuration, an effect of facilitating the manufacture can be obtained. Further, since the cable has a centrally symmetric structure, the remanent polarization is formed radially from the center. For this reason, isotropic detection is possible with respect to pressure application from any direction. Therefore, even when the pressure detecting element is rotated or twisted at the time of installation, the response voltage hardly changes. As a result, the degree of freedom of arrangement is increased, and the effect of enabling stable determination of whether or not pressure is applied and stable location coordinate determination can be obtained.

  The flexibility increasing portion 15 in the pressure detecting element of the present invention is made of a material having a smaller elastic modulus than that of the protective layer 13, the flexible pressure sensitive body 11, the internal electrode 16, and the external electrode 17. When the pressure Po is applied, the flexible pressure-sensitive body 11 can be largely bent downward. Specifically, the same material as the protective layer 13 described below, such as thermoplastic elastomer and vulcanized rubber, having a low elastic modulus is preferably used.

In addition, as the flexible increase portion 15, a structure having a smaller elastic modulus, which is constituted by a cavity having air inside thereof, or made of a large number of fine foams is preferably used. In particular, since the foam has a uniform structure, isotropic detection is possible even when pressure is applied from any direction.
The pressure detecting element of the present embodiment has been described by taking the form having a layered structure and the form having a cable-like structure as an example, but what is effective in one form is also effective in the other form, particularly illustrated. It is not limited to the form.
However, many of them including the following embodiments are described with respect to a cable-shaped pressure detection element. This is because the following effects can be obtained as already described.

  Since the pressure detection element can be manufactured by a continuous extrusion process if the pressure detection element is in the form of a cable, an effect of facilitating manufacture can be obtained. Also, since it is in the form of a coaxial cable, the external electrode is formed around the core internal electrode and the flexible pressure sensitive body to have a centrally symmetric structure, and the residual polarization is formed radially from the center. . For this reason, isotropic detection is possible with respect to pressure application from any direction.

  Therefore, even if the pressure detection element rotates or twists during installation, the response voltage hardly changes. As a result, there is an effect that the degree of freedom of arrangement is increased and stable determination of the presence or absence of pressure application is possible.

  The materials used in the flexible pressure sensitive body of the present embodiment will be described below. The flexible pressure sensitive body 11 is configured by dispersing piezoelectric ceramic powder in synthetic rubber or synthetic resin. As the synthetic rubber or synthetic resin, a thermoplastic resin such as vinyl chloride, a thermoplastic elastomer such as chlorinated polyethylene, a vulcanized rubber such as EPDM, or the like is used. Piezoelectric ceramics include compounds having a perovskite structure such as lead titanate, lead zirconate, lead zirconate titanate, barium titanate, bismuth / sodium titanate, bismuth / sodium titanate-barium titanate, and alkali niobate. Ceramic materials that exhibit piezoelectricity such as a compound having a bismuth layer structure and a compound having a tungsten bronze structure are used.

  As the protective layer 13, at least one of a thermoplastic elastomer and a vulcanized rubber used for the flexible pressure-sensitive body 11 is used.

  As the flexibility increasing portion 15, the protective layer 13, the thermoplastic elastomer contained in the flexible pressure sensitive body 11, and the same material as the vulcanized rubber having a low elastic modulus are used. For example, a foam of the same material or a structure having a cavity made of the same material is preferably used, and as described above, the above-mentioned foam is particularly preferably used.

  As the electrode 12 and the external electrode 16, a wire material such as C, Pt, Au, Pd, Ag, Cu, Al, Ni, stainless steel or the like rolled into a flat tape shape or the like is used. Alternatively, if the tape-like polymer film laminated with the metal wire or the tape-like wire is used, a more flexible external electrode can be obtained. Moreover, the electrode which covered the flexible pressure-sensitive body 11 by knitting a metal fine wire independently can also be used. Or what formed the said metal as a thin film by vapor deposition, sputtering, etc. is used.

  The flexibility increasing portion 15 is formed as a part of the electrode 12 or the external electrode 16 in FIGS. 3A, 3B, 4A, 4B, 5A, and 5B. In the case of the pressure detection element shown, the flexibility increasing portion 15 may be bonded and integrated with the main body of the electrode 12 or the external electrode 16 in some cases. For example, a material obtained by rolling a metal into a tape shape, a tape-shaped material bonded to a tape-shaped polymer, or a material bonded to the flexibility increasing portion 15 is used. Further, there is a case in which a metal rolled into a tape shape is directly bonded to the flexibility increasing portion 15.

  As the internal electrode 16, a single or a plurality of fine metal wires used for the external electrode 17, a fiber such as polyester wound around the metal wire, or the like is used.

  Further, regarding the flexible pressure-sensitive body 11, the protective layer 13, the electrode 12, the internal electrode 16, and the external electrode 17, the same can be applied to the following embodiments.

Next, a general example will be described particularly regarding the method for manufacturing the cable-shaped pressure detection element. First, a piezoelectric ceramic powder and a thermoplastic elastomer as a synthetic rubber or a synthetic resin are kneaded to form a composite. Next, by extruding this composite together with the internal electrode 16 using an extruder, a cable having the flexible pressure-sensitive body 11 made of the above composite formed around the internal electrode 16 is obtained. . Further, a polarization electrode covering the periphery of the cable is prepared, and by applying a voltage between this electrode and the internal electrode 16 in the cable, an electric field is formed radially from the internal electrode, and a piezoelectric ceramic having a corresponding orientation is formed. Forms polarization in the body.

  Further, after removing the electrode for polarization, the external electrode 17 is formed by winding a tape-shaped metal wire, a tape-shaped metal, or a tape in which the tape-shaped metal and the tape-shaped polymer are bonded around the cable. To do. Next, the pressure detection element 14 is obtained by extruding synthetic rubber, synthetic resin or the like with an extruder to form the protective layer 13 of the cable around the cable on which the external electrode 17 is formed. Polarization can also be performed by applying a voltage between the external electrode 17 and the internal electrode 16 after the external electrode 17 is formed. Moreover, the protective layer 13 may be formed by adhesion.

  The piezoelectric ceramic in the flexible pressure sensitive element in the pressure detecting element of the present invention is preferably one that does not contain lead in view of disposal processing. For example, barium titanate, bismuth / sodium titanate, bismuth / sodium titanate-barium titanate, alkali niobate, etc. are preferably used. Furthermore, when used outdoors, such as for security purposes, or in environments using water such as toilets, baths, and kitchens, it is more preferable that the piezoelectric ceramic powder is subjected to a water repellent treatment to prevent moisture from entering. This is because the piezoelectric ceramic containing the above alkali metal easily absorbs moisture, and the performance easily fluctuates accordingly.

  Note that the materials and methods described in this embodiment can also be suitably applied to the following embodiments.

(Embodiment 2)
In the second embodiment, the same configurations as those of the first embodiment are provided with the same reference numerals and the detailed description is omitted, and only different portions will be described. As described above, the main feature of the present invention is to suppress the decrease in the response voltage due to the curing of the flexible pressure-sensitive body 11 at a low temperature by suppressing the deformation in the compression mode and promoting the deformation in the bending mode. It is an idea.

  In the first embodiment, the configuration that mainly promotes the deformation in the bending mode (the configuration in which the bending depth corresponding to FIG. 2C increases) has been described, but in the present embodiment, the deformation in the compression mode is mainly suppressed. By doing so, a configuration that relatively promotes deformation by expanding the width of the bending mode will be described with reference to FIGS. 8A and 12B to FIGS. By suppressing the deformation in the compression mode, a decrease in the response voltage V corresponding to the compression + deflection mode in FIG. 1C at a low temperature is further suppressed, and the effect of further increasing the accuracy of pressure detection at a low temperature is obtained. It is done.

  The vertical and horizontal directions used in the following description are defined by defining the direction parallel to the direction in which the external force Po is applied as the vertical direction and the orthogonal direction as the horizontal direction.

  As a specific configuration for suppressing deformation due to the compression mode, the protective layer has its elastic modulus in the vertical direction (direction parallel to the direction in which external force Po is applied) in the horizontal direction (external force). There is a configuration that becomes larger than a portion in a direction in which Po is applied and a direction perpendicular to the direction in which Po is applied. By increasing the elastic modulus of the protective layer in the vertical direction, deformation of the compression mode corresponding to the vertical direction is suppressed.

  In the present embodiment, this configuration will be described. The elastic modulus defined here will be described below.

  Here, the elastic modulus of the electrode and the flexible pressure sensitive body, which should be particularly noted, will be described with reference to FIGS. 6 (a) and 6 (b) and FIGS. 7 (a) and 7 (b). Further, the elastic modulus of the electrode will be described focusing on the external electrode 17 that is provided on the entire outer periphery of the flexible pressure sensitive body 11 and has a great influence on the bending of the flexible pressure sensitive body 11.

  First, FIGS. 6A and 6B show that only the external electrode 17 except the internal electrode 16, the protective layer 13, and the flexible pressure sensitive body 11 is removed from the cable-shaped pressure detection element 14, and the external force is applied. The distortion when FS is added is expressed as a change in cross-sectional shape. 6A shows the distortion in the vertical direction, and FIG. 6B shows the distortion in the horizontal direction.

  Specifically, with respect to the vertical direction, as shown in FIG. 6 (a), the distortion of the upper and lower portions, which are vertical portions that are the directions in which the force Fs is applied from the outside, is measured for elastic modulus measurement. Then, the elastic modulus of the portion of the external electrode 17 in the vertical direction is defined by Fs / xv. Similarly, the elastic modulus of the portion of the external electrode 17 in the horizontal direction is defined as Fs / xh, where xh is the distortion of the portion in the horizontal direction with respect to the external force Fs. As an example, if the material of the external electrode 17 is uniform, the thickness of the side portion of the external electrode 17 is thicker than the thickness of the upper and lower portions of the external electrode 17 as shown in FIGS. The elastic modulus of the vertical portion is larger than the elastic modulus of the horizontal portion, and the external electrode 17 is less likely to be distorted in the vertical (compressed) direction than the horizontal direction, and is relatively in a bending mode. Promotes deformation due to widening.

  Next, FIGS. 7A and 7B show the elastic modulus of the cable-like pressure detecting element 14 except for the internal electrode 16, the protective layer 13, and the external electrode 17, and only the flexible pressure-sensitive body 11. The strain when the force FS is applied from the outside for measurement is expressed as a change in cross section. FIG. 7A shows distortion in the vertical direction, and FIG. 7B shows distortion in the horizontal direction.

  Similar to the pressure detection element 14 of FIGS. 6A and 6B, the elastic modulus of the upper and lower portions, which are vertical portions, which are the directions in which the force FS is applied from the outside of the flexible pressure-sensitive body 11, is Fs / xv. The elastic modulus of the left and right side portions, which are horizontal portions in which the force FS is not applied from the outside of the flexible pressure-sensitive body 11, is defined by Fs / xh. Similarly to the pressure detecting element 14 in FIGS. 6A and 6B, considering the case where the material of the external electrode 17 is uniform, the flexible pressure sensitive body 11 as shown in FIGS. 7A and 7B. When the thickness of the side portion is larger than the thickness of the upper and lower portions, the elastic modulus Fs / xv of the upper portion and the lower portion of the flexible pressure-sensitive body 11 that is the vertical portion is the horizontal portion. The elastic modulus 11 is greater than the elastic modulus Fs / xh of the portion, and the flexible pressure-sensitive body 11 is less likely to be distorted in the vertical (compression) direction than in the horizontal direction, and relatively promotes deformation by expanding the width of the bending mode.

  First, regarding a specific configuration of the external electrode 17 of the present embodiment, an example in which the above elastic modulus is realized will be described with reference to FIGS. 8A and 8B are cross-sectional views of the cable-shaped pressure detection element 14, FIG. 8A is a cross-sectional view in the longitudinal direction, and FIG. 8B is a position along the line EE in FIG. 8A. The cross section at is shown.

  The external electrode 17 that is a feature of this configuration is that the left and right side external electrodes 17 that are horizontal portions are thicker than the upper and lower external electrodes 17 that are vertical portions. As a result, the elastic modulus of the external electrode 17 in the vertical portion is larger than the elastic modulus of the external electrode 17 in the horizontal portion, and vertical compression is suppressed.

As described above, since the elastic modulus of the external electrode 17 in the horizontal direction is small, deformation of the bending mode corresponding to deformation of the pressure detection element in the cable longitudinal direction in the horizontal direction is suppressed. In this way, the deformation in the compression mode is suppressed, the deformation by relatively widening the width of the bending mode is relatively promoted, and a configuration in which the deformation in the bending mode is mainly realized. Therefore, even when the flexible pressure sensitive body 11 is cured at a low temperature, an effect of suppressing a decrease in response voltage can be obtained.

  As the external electrode in this case, for example, an elastomer in which a conductor such as metal or carbon is dispersed can be suitably used because it is easy to adjust the thickness of the vertical and horizontal portions.

  Next, regarding another configuration of the present embodiment, an example in which the above elastic modulus is realized with respect to the flexible pressure-sensitive body 11 will be described with reference to FIGS. 9A and 9B. 9 (a) and 9 (b) are cross-sectional views of the cable-shaped pressure detecting element 14, FIG. 9 (a) is a longitudinal cross section, and FIG. 9 (b) is the position of the FF line in FIG. 9 (a). The cross section at is shown. The flexible pressure-sensitive body 11 which is a feature of this configuration is that the thickness of the flexible pressure-sensitive body 11 on the left and right sides in the horizontal direction, which is a portion in the direction in which the external force Po is not applied, is the force from the outside. The point is thicker than the upper and lower flexible pressure-sensitive bodies 11 in the vertical direction, which is a portion in the direction of addition of Po.

  For this reason, similarly to the pressure detection element 14 in FIGS. 8A and 8B, deformation in the compression mode is suppressed, and the deformation due to the expansion of the width of the bending mode is relatively promoted. Is realized. Therefore, even when the flexible pressure sensitive body 11 is cured at a low temperature, an effect of suppressing a decrease in response voltage can be obtained.

  To change the elastic modulus of the electrode and flexible pressure sensitive body defined in FIGS. 6 (a), 6 (b), 7 (a) and 7 (b), the thickness of the electrode and flexible pressure sensitive body must be changed. In addition, a region for suppressing deformation in the compression mode can be provided in a part of the electrode and the flexible pressure-sensitive body. This case will be described with reference to FIGS. 10A, 10B, 11A, 11B, 12A, and 12B.

  Next, another configuration of the pressure detection element according to the present embodiment will be described with reference to FIGS. 10 (a) and 10 (b) are cross-sectional views of the rectangular cable-shaped pressure sensing element 14, FIG. 10 (a) is a longitudinal cross-section, and FIG. 10 (b) is a cross-sectional view of G− in FIG. A cross-section at the G-line position is shown. The thickness of the external electrode 17 is the same in the upper, lower, and left and right side portions, but the compression suppressing portion 18 is embedded in the left and right side portions of the external electrode 17. It is.

  As the compression suppressing portion 18, one having a higher elastic modulus (larger) than that of the external electrode 17 is used. By doing so, the elastic modulus defined in FIGS. 6A, 6B, 7A, and 7B in which the external electrode 17 and the compression suppressing portion 18 are combined is set to the force Po from the outside. It is possible to make the height in the vertical direction, which is a portion in the applied direction, higher than in the horizontal direction, which is a portion in the direction in which the external force Po is not applied.

 As a result, a configuration in which the deformation in the compression mode is suppressed and the deformation in the bending mode is increased is realized. Therefore, even when the flexible pressure sensitive body 11 is cured at a low temperature, an effect of suppressing a decrease in response voltage can be obtained.

Further, another configuration of the pressure detection element of the present embodiment will be described with reference to FIGS. 11 (a) and 11 (b) are cross-sectional views of the pseudo-cable-shaped quadrilateral pressure detection element 14, FIG. 11 (a) is a longitudinal cross section, and FIG. 11 (b) is a cross-sectional view of H in FIG. 11 (a). The cross section at the position of line -H is shown. The flexible pressure-sensitive body 11 of the present embodiment is that two electrodes 12 are formed in pairs along the longitudinal direction, and a compression suppressing portion 18 is formed between the electrodes 12. The pressure detection element 14 detects the response voltage V when the external pressure Po is applied from the vertical direction (vertical direction) of the outer protective layer 13 as a voltage generated between the two electrodes 12. Is done.

  In this way, the elliptical compression suppressing portion 18 is formed in the flexible pressure-sensitive body 11 along the direction in which the external pressure Po is applied, with the electrode 12 positioned on the upper and lower sides in the direction in which the pressure Po is applied. Therefore, the deformation in the compression mode is suppressed, and the effect of preferentially proceeding with the deformation due to the expansion of the width of the bending mode is realized. Therefore, even when the flexible pressure sensitive body 11 is cured at a low temperature, an effect of suppressing a decrease in response voltage can be obtained.

  In the case of this configuration, the pressure sensing element 14 can be obtained by forming the flexible pressure sensitive body 11 and the protective layer 13 around the electrode 12 by one extrusion each time. Therefore, compared with the conventional cable-shaped pressure sensing element. Thus, the step of forming the external electrode 17 is eliminated, and an effect of facilitating manufacturing can be obtained.

  In order to reduce electromagnetic noise from the outside, it is preferable to use a conductive elastomer as the protective layer 13. Therefore, an elastomer to which a conductive filler such as metal or carbon is added is used.

  Furthermore, another configuration of the pressure detection element of the present embodiment will be described with reference to FIGS. 12 (a) and 12 (b) are cross-sectional views of the cable-shaped quadrilateral pressure detection element 14, FIG. 12 (a) is a cross-sectional view in the longitudinal direction, and FIG. 12 (b) is a cross-sectional view of FIG. A cross section at the I-line position is shown. The characteristic flexible pressure-sensitive body 11 has the same thickness at the upper and lower portions that are portions where the external pressure Po is applied, and the left and right side portions that are portions where the external pressure Po is not applied. However, the compression suppressing portion 18 is provided in the left and right side portions of the flexible pressure-sensitive body 11.

  As described above, since the material having a higher elastic modulus (larger) than the flexible pressure sensing body 11 is used for the compression restraining portion 18, the flexible pressure sensing body 11, the compression restraining portion 18, and the like. 6 (a), (b), FIG. 7 (a), and (b), the elastic modulus in the vertical direction, which is the portion in the direction in which the external pressure Po is applied, from the outside. It is possible to adjust higher than the horizontal direction, which is a portion in the direction where the pressure Po is not applied.

  In addition, the material which comprises the compression suppression layer 18 of this Embodiment specifically has an elastic modulus compared with what is used for the flexible pressure sensitive body 11 in thermoplastic elastomer, crosslinked rubber, etc. Higher materials are preferably used, and general resins and metals can be used as long as they have elasticity to bend in the vertical direction.

(Embodiment 3)
Next, a third embodiment will be described. In the present embodiment, the same configurations and effects as those of the first and second embodiments are provided with the same reference numerals, the description thereof is omitted, and only different portions will be described.

  As described above, the present invention includes (1) a configuration that promotes deformation in the bending mode, and (2) a configuration that suppresses deformation in the compression mode. By suppressing the deformation in the compression mode and promoting the deformation in the bending mode, a decrease in the response voltage due to the curing of the flexible pressure-sensitive body 11 at a low temperature is suppressed, and high-precision pressure detection is possible even when the environmental temperature changes. It is the significance of the present invention to make this possible.

  The first embodiment has already described mainly (1) a configuration that promotes deformation in the bending mode (a configuration in which the bending depth corresponding to (c) in FIG. 2 increases). In the second embodiment, mainly (2 ) The configuration for suppressing the deformation in the compression mode (deformation by expanding the bending width corresponding to FIG. 2B) has been described.

  In this embodiment, (1) among the configurations that promote the deformation in the bending mode, in order to increase the bending width corresponding to FIG. 2B, FIG. This will be described with reference to FIGS. 16 (a) and 16 (b).

  13 (a) and 13 (b) are cross-sectional views of the cable-shaped pressure detecting element 14, FIG. 13 (a) is a cross section in the longitudinal direction, and FIG. 13 (b) is a line JJ in FIG. 13 (a). A cross-section at the position is shown. The characteristic internal electrode 16 is formed in an elliptical shape along the direction in which pressure Po from the outside is applied, and is formed by embedding an ellipse-shaped bending width expanding portion 19 in the direction in which pressure Po from the outside is applied inside. It is a point that has been. In the drawing, the external electrode 17 has a circular shape, and the protective layer 13 has a rectangular shape.

  The bending width expanding portion 19 is formed of a material having a higher elastic modulus than that of the flexible pressure-sensitive body 11, and, as can be seen in FIG. 13B, in the vertical direction (direction parallel to the direction in which the external pressure Po is applied). Has an elongated configuration. For this reason, when an external pressure Po is applied, the entire upper and lower portions, which are portions of the internal electrode 16 in the direction in which the external pressure Po is applied, are pulled in the longitudinal direction by the bending width expanding portion 19 and bent. As a result, as shown in FIG. 2B, the effect of increasing the deflection width can be obtained.

  Thus, by promoting deformation in the bending mode, even when the flexible pressure sensitive body 11 is cured at a low temperature, a decrease in response voltage is suppressed, and a highly accurate pressure detection is possible even when the environmental temperature changes. The effect becomes.

  14A and 14B are cross-sectional views of another configuration of the cable-shaped pressure detection element 14 according to the present embodiment. FIG. 14A is a cross-sectional view in the longitudinal direction, and FIG. The cross section in the KK line position of (a) is represented. The characteristic internal electrode 16 is that it is formed by integrally connecting a portion separated into an upper part and a lower part along the direction in which the pressure Po from the outside is applied, by a bending width expanding part 19.

  And even if the internal electrode 16 is formed only with the two internal electrodes 16 positioned at the upper part and the lower part, both of them pull the flexible pressure-sensitive body 11 in a wide region in the longitudinal direction. When is applied, the flexible pressure-sensitive body 11 bends in a wide area.

  Further, since the positional relationship between the internal electrodes 16 located at the upper part and the lower part is also fixed in the bending width expanding part 19, when the upper internal electrode 16 is bent, the lower internal electrode 16 is also bent by the bending width expanding part. As a result, it is possible to obtain an effect that the whole is further bent uniformly. As a result, the bending width of the pressure detecting element 14 is widened. As described above, by promoting the deformation in the bending mode, even when the flexible pressure-sensitive body 11 is cured at a low temperature, a decrease in the response voltage is suppressed, and highly accurate pressure detection is possible even when the environmental temperature changes. A possible effect is obtained.

  In the case of the pressure detection element shown in FIGS. 14A and 14B, the bending width expanding portion 19 is formed of, for example, a resinous sheet and bonded to the two internal electrodes 16. A general resin material can be used as long as it is harder to expand and contract than the flexible pressure-sensitive body 11 and has a high elastic modulus in the longitudinal direction of the cable. In particular, a resin plate or a metal plate that is thin and bends well but hardly stretches or contracts is particularly preferably used, but the material is not particularly limited. When a thin metal plate is used, it can be configured as an integrated internal electrode having the same potential as the two internal electrodes 16.

FIGS. 15A and 15B are cross-sectional views of another configuration of the cable-shaped pressure detecting element 14 according to the present embodiment. FIG. 15A is a cross-sectional view in the longitudinal direction, and FIG. The cross section in the LL line position of (a) is represented. The characteristic bending width expanding portion 19 is formed in a thin line shape, is along the longitudinal direction of the portion to which the pressure Po is applied from the outside of the flexible pressure-sensitive body 11, and is compared with 17 on the external electrode. It is a point that is buried and formed at a position close to the ground.

  The bending width expanding portion 19 is made of a material having a larger elastic modulus in the longitudinal direction than the flexible pressure sensitive body 11. For this reason, when the pressure Po from the outside is applied, the entire flexible pressure-sensitive body 11 tries to bend by being pulled in the longitudinal direction by the bending width expanding portion 19 having a high elastic modulus in the longitudinal direction. Thus, as shown in FIG. 2B, the effect of increasing the deflection width is obtained.

  In this way, the pressure detection element 14 is promoted to bend in the bending mode, so that even when the flexible pressure-sensitive body 11 is cured at a low temperature, a decrease in the response voltage is suppressed and the environmental temperature changes. An effect of enabling highly accurate pressure detection is obtained.

  Moreover, it is preferable that the bending width expansion part 19 is fixed to the flexible pressure-sensitive body 11 without slipping. An adhesive may be used for the fixing, but the interface on the bonding side of the flexible pressure-sensitive body 11 and the bending width expanding portion 19 has irregularities so that they are more strongly bonded. Structures that penetrate each other are preferred. In addition, the fixing can be performed by fusion when the flexible pressure-sensitive body 11 and the bending width expanding portion 19 are both formed of thermoplastic resin.

  Moreover, as a material used for the bending width expansion part 19, the material which is hard to expand and contract than the flexible pressure-sensitive body 11 and has a high elastic modulus in the longitudinal direction of the cable shape is used. In particular, a resin plate, fiber, fiber bundle, metal plate, metal wire, or the like that is thin and bends well but hardly stretches or contracts is particularly preferably used.

  FIGS. 16A to 16D show the structure of the bending width expanding portion 19 formed in the flexible pressure-sensitive body 11 described above. As already described, the bending width expanding portion 19 is a member that pulls the flexible pressure-sensitive body 11 in the longitudinal direction to bend over a wide range, so that the flexible pressure-sensitive body 11 does not slip in the flexible pressure-sensitive body 11 and firmly It is important that the flexible pressure sensitive body 11 is fixed.

  Therefore, as shown in FIGS. 16A to 16D, it is preferable that the bending width expanding portion 19 has a structure with large unevenness. Specifically, those having many convex portions 19a as shown in FIG. 16 (a) and those having many concave portions 19b as shown in FIG. 16 (b) are preferable. Also, a linear object 19d is formed by winding a linear object around the main shaft 19c as shown in FIG. 16 (c), or a plurality of lines are wound around as shown in FIG. 16 (d). A structure in which a large number of striped convex portions 19e are formed on the surface is preferable.

  The material is not particularly limited as long as it has a property of bending as a wire, and can be formed of metal, resin, carbon, or the like.

  Further, even if a planar bending width expanding portion knitted with a fine metal wire is formed in the flexible pressure-sensitive body 11, an excellent effect of expanding the bending width can be obtained.

  It should be noted that the configuration of the bending width expanding portion 19 shown in FIGS. 14A and 15A can be applied to the pressure detection elements of the first and second embodiments.

As described above, since the pressure detection element of the present invention can detect pressure with high accuracy even when the environmental temperature to be used changes, it is particularly suitable for applications that are used outdoors or in environments close to the outdoors. It is done. For example, it is particularly suitable for security purposes, such as installation outside a house such as a balcony or fence to detect intruders. In addition, it is used to detect the trapping of people or objects in the doors of automobiles and buildings, or to detect contact with the door handle to unlock the door simply by touching the door handle. Suitable for

(A) Cross-sectional view when the pressure detection element is placed on a rigid body and pressure is applied from above with an indenter (b) Cross-sectional view when the pressure detection element is placed on a sponge and pressure is applied from above with an indenter ( c) Qualitative representation of the temperature characteristics of the response voltage corresponding to the pressure sensing element shown in FIGS. (A) Cross-sectional view showing a state of deformation of the flexible pressure-sensitive body of the pressure detecting element and the electrode. (B) Expressing promotion of deformation of the flexible mode in which the bending width of the flexible pressure-sensitive body and the electrode widens. Sectional view (c) Sectional view showing acceleration of deformation in bending mode in which bending depth of flexible pressure-sensitive body and electrode is increased (A) Cross-sectional view in the longitudinal direction of the pressure detection element in the first embodiment of the present invention (b) Cross-sectional view taken along the line BB in FIG. 3 (a) (A) Longitudinal sectional view of a pressure detecting element of another configuration according to Embodiment 1 of the present invention (b) Cross sectional view taken along line CC in FIG. 4 (a) (A) Longitudinal sectional view of pressure detecting element in Embodiment 1 of the present invention (b) FIG. 5 (a) Cross sectional view taken along the line DD (A) The figure explaining the elastic modulus of the external electrode of the pressure detection element in the second embodiment of the present invention in the vertical direction (b) The figure explaining the elastic modulus of the external electrode of the pressure detection element in the horizontal direction (A) The figure explaining the elastic modulus of the vertical direction of the flexible pressure sensing element of the pressure detection element of Embodiment 2 of this invention (b) The figure explaining the elastic modulus of the horizontal direction of the pressure detection element (A) Cross-sectional view in the longitudinal direction of the pressure detection element in Embodiment 2 of the present invention (b) Cross-sectional view taken along the line EE in FIG. 8 (a) (A) Longitudinal sectional view of a pressure detecting element of another configuration according to Embodiment 2 of the present invention (b) Cross sectional view taken along line FF in FIG. 9 (a) (A) Longitudinal sectional view of the pressure detection element according to the second embodiment of the present invention (b) Cross sectional view taken along line GG in FIG. 10 (a) (A) Longitudinal sectional view of a pressure detecting element of another configuration according to Embodiment 2 of the present invention (b) Cross sectional view taken along line HH in FIG. 11 (a) (A) Longitudinal sectional view of a pressure detecting element of another configuration according to Embodiment 2 of the present invention (b) Cross sectional view taken along line II in FIG. 12 (a) (A) Cross-sectional view in the longitudinal direction of the pressure detecting element in Embodiment 3 of the present invention (b) Cross-sectional view taken along line JJ in FIG. 13 (a) (A) Cross-sectional view in the longitudinal direction of a pressure detecting element having another configuration according to Embodiment 3 of the present invention (b) Cross-sectional view taken along the line KK in FIG. 14 (a) (A) Cross-sectional view in the longitudinal direction of a pressure detecting element having another configuration according to Embodiment 3 of the present invention (b) Cross-sectional view taken along line LL in FIG. 15 (a) (A), (b), (c), (d) The schematic diagram showing the structure of the bending width expansion part shown to Fig.15 (a) in Embodiment 3 of this invention. Sectional view of a conventional layered pressure sensor (A) Cross-sectional view in the longitudinal direction of a conventional cable-shaped pressure detecting element (b) Cross-sectional view taken along line AA in FIG. 18 (a)

Explanation of symbols

11 Flexible pressure sensitive body
12 electrodes
13 Protective layer
14 Pressure sensing element
15 Flexibility increase part 16 Internal electrode 17 External electrode
18 Compression suppression unit
19 Deflection width expansion part

Claims (10)

A pressure detection element comprising: a flexible pressure sensitive body having remanent polarization; and a plurality of electrodes for extracting signals from the flexible pressure sensitive body, wherein the electrodes have a flexibility increasing portion. The pressure detecting element according to claim 1, wherein the flexibility increasing portion is made of a foam. The pressure detecting element according to claim 1, wherein the flexibility increasing portion is formed on an electrode on a side opposite to a side to which an external force of the flexible pressure sensitive body is applied. A flexible pressure-sensitive body having remanent polarization; and a plurality of electrodes for extracting signals from the flexible pressure-sensitive body, wherein the electrode has an elastic modulus in a direction in which an external force is applied to a portion in a direction in which no external force is applied The pressure sensing element is made larger. The pressure detection element according to claim 4, wherein the electrode has a thickness in a direction in which an external force is applied thinner than a thickness in a direction in which no external force is applied. The pressure detection element according to claim 4, wherein the electrode has a compression suppressing portion in a portion in a direction in which an external force is applied. A flexible pressure-sensitive body having remanent polarization; and a plurality of electrodes for extracting signals from the flexible pressure-sensitive body. The flexible pressure-sensitive body applies an external force to an elastic modulus in a direction in which an external force is applied. A pressure sensing element that is larger than the non-directional part. The pressure detection element according to claim 7, wherein the flexible pressure-sensitive body has a thickness in a direction in which an external force is applied thinner than that in a direction in which no external force is applied. The pressure detection element according to any one of claims 1 to 8, wherein the electrode has a bending width expanding portion. The pressure detection element according to any one of claims 1 to 9, wherein the flexible pressure-sensitive body has a bending width expanding portion.