JP6902507B2 - Pressure sensor - Google Patents

Description

The present invention relates to a pressure sensor that measures biological information.

In recent years, pressure-sensitive sensors have been used for measuring the pressure distribution of a sleeping posture on a bed and the pressure distribution of a sitting posture on a chair or the like as biological information for the purpose of nursing care and health promotion. In the application of measuring biological information by contacting the body in this way, a pressure sensor that can measure a wide range of pressure distribution with a size corresponding to the body is required while having flexibility that does not cause discomfort to the body. There is.

Conventionally, a first electrode, a second electrode facing the first electrode, and a dielectric layer arranged between the first electrode and the second electrode and elastically deformed according to fluctuations in biological information are provided as pressure-sensitive portions. A capacitance type pressure sensor has been proposed (see Patent Document 1: JP-A-2017-176498).

Further, the first layer sheet, the second layer sheet and the third layer sheet are provided as pressure sensitive parts, and the first layer sheet and the third layer sheet have conductive paths to which conductive particles are applied at predetermined intervals. The orientation of the conductive path of the first layer sheet is lateral to the orientation of the conductive path of the third layer sheet, and the second layer sheet is a pressure-sensitive sheet made of cloth having electrical characteristics that change with pressure. It has been proposed (see Patent Document 2: US Pat. No. 8,966,997).

JP-A-2017-176498 U.S. Pat. No. 8,966,997

In the configurations of Patent Document 1 and Patent Document 2, the pressure-sensitive characteristics change with time due to deformation of the pressure-sensitive portion due to compression set, and the reproducibility of the pressure-sensitive value deteriorates. Further, the contact resistance between the electrode portion and the pressure-sensitive portion changes with time due to oxidation of the electrode surface or the like, and the reproducibility of the pressure-sensitive value is lowered. In such a case, it is necessary to calibrate the pressure-sensitive characteristics in order to prevent a decrease in the reproducibility of the pressure-sensitive value. The calibration equipment is expensive, the pressure sensor cannot be used during the period for sending the pressure sensor to the facility having the calibration equipment, and the burden of transportation costs related to the calibration is large. In addition, since the pressure-sensitive characteristics of the pressure-sensitive part also change due to changes in the usage environment such as temperature and humidity, it is necessary to attach a temperature sensor and humidity sensor for correction externally, and water is applied to the pressure-sensitive part. In order to detect an abnormality such as when immersed, it is necessary to attach a water detection sensor or the like externally. With these external sensors, the pressure-sensitive sensor becomes large-scale, and the cost increases by the amount of the external sensor.

The present invention has been made in view of the above circumstances, and is corrected or calibrated while maintaining and improving the reproducibility of the pressure-sensitive value while maintaining and improving the reproducibility of the pressure-sensitive value while eliminating the external sensors such as the temperature sensor, the humidity sensor, and the water detection sensor. It is an object of the present invention to provide a pressure sensor having a structure that can be easily used.

As an embodiment, the problem is solved by a solution means as disclosed below.

The pressure-sensitive sensor of the present invention has a sheet portion made of a dielectric or a conductor, a first electrode portion arranged on the first main surface of the sheet portion, and a second main surface arranged on the second main surface of the sheet portion. The first electrode portion is provided with two electrode portions, and a plurality of first electrodes are formed at the first interval, and the second electrode portion is formed with a plurality of second electrodes at the second interval. The second electrode is arranged so as to intersect with the first electrode, and the intersecting region between the first electrode and the second electrode is formed in a matrix arrangement, or is composed of a dielectric or a conductor. A sheet portion, a plurality of first electrode portions arranged on the first main surface of the seat portion at a first interval, and a second interval on the second main surface of the sheet portion in a direction intersecting with the first electrode portion. A plurality of second electrode portions arranged in the above section are provided, and the intersecting region between the first electrode portion and the second electrode portion is formed in a matrix arrangement, and at least one of the intersecting regions is formed. A pressure holding portion for holding the first electrode portion and the second electrode portion at a predetermined pressure in a compression direction approaching each other is arranged , and the pressure holding portion is at least one of the intersecting regions at the four corners. It is characterized in that it is arranged in one of the intersecting regions, and the pressure distribution at a position different from that of the pressure holding portion is corrected or calibrated according to the pressure sensitive value at the position where the pressure holding portion is arranged. To do.

According to this configuration, a pressure holding portion that holds the pressure at a predetermined pressure in the compression direction is arranged, and the pressure-sensitive portion is deformed due to compression set, the contact resistance between the electrode portion and the pressure-sensitive portion, temperature, humidity, etc. Correction or calibration while maintaining and improving the reproducibility of the pressure-sensitive value by treating abnormalities such as changes in the usage environment and when water is immersed in the pressure-sensitive part with the pressure-sensitive value of the pressure-holding unit as a reference. Is a simple configuration.

The pressure holding portion is arranged in at least one of the intersecting regions at the four corners, and the pressure at a position different from that of the pressure holding portion depends on the pressure sensitive value at the position where the pressure holding portion is arranged. It is preferable that the configuration is such that the distribution is corrected or calibrated. According to this configuration, since the pressure holding portion is arranged at a position deviated from the center of contact with the body, the measurement of biological information can be performed without any trouble even in the case of a thick pressure holding portion.

The pressure holding portions are arranged at a plurality of locations in the intersecting region, and it is preferable that the pressure of the pressure holding portions at each position is different. According to this configuration, for example, the pressure of the pressure holding portion is corrected within the range of use of the pressing force by making the pressure different between the lower limit value and the upper limit value of the pressing force of 10 to 200 [mmHg]. Alternatively, the measurement accuracy of calibration can be improved.

The pressure holding portion preferably has an elastic body that applies a predetermined pressure in the compression direction. According to this configuration, it is easy to adjust the pressing force to a desired value.

It is preferable that the sheet portion, the first electrode portion and the second electrode portion are all woven fabrics, or the sheet portion, the first electrode portion and the second electrode portion are all knitted. According to this configuration, it is possible to measure a stable pressure distribution while taking advantage of the flexibility of the cloth.

It is preferable that the first electrode portion is sewn to the seat portion by the suture and the second electrode portion is sewn to the seat portion by the suture. According to this configuration, the configuration has high productivity. Moreover, since the position of the boundary of the crossing region is stabilized by sewing, the measurement accuracy of the pressing force in each crossing region can be improved.

It is preferable that the suture is sewn to at least one of the intersecting regions at the four corners to form the pressure holding portion. According to this configuration, the pressure sensor has a small thickness, and the material cost can be suppressed.

According to the present invention, a pressure holding portion that holds a predetermined pressure in the compression direction is arranged, and deformation of the pressure sensitive portion due to compression set, contact resistance between the electrode portion and the pressure sensitive portion, temperature, humidity, etc. Correction or calibration while maintaining and improving the reproducibility of the pressure-sensitive value by treating abnormalities such as changes in the usage environment and when water is immersed in the pressure-sensitive part with the pressure-sensitive value of the pressure-holding unit as a reference. It is a pressure-sensitive sensor with a configuration that can be easily performed.

FIG. 1 is a schematic perspective view showing an example of a pressure sensor according to the first embodiment of the present invention. FIG. 2 is a schematic plan view showing an example of the pressure sensor of the first embodiment. FIG. 3A is a schematic front view showing an example of the pressure sensor of the first embodiment, and FIG. 3B is a schematic side view showing an example of the pressure sensor of the first embodiment. FIG. 4 is a sectional view taken along line IV-IV in FIG. FIG. 5 is a sectional view taken along line VV in FIG. FIG. 6A is a schematic cross-sectional view of a state in which a bobbin thread is passed through a loop-shaped upper thread penetrating the electrode cloth and the conductive cloth by a sewing machine to form a knot, and FIG. 6B shows the electrode cloth and the conductive cloth by pulling up the knot. FIG. 6C is a schematic cross-sectional view of a state in which the knot is arranged between and, and FIG. 6C is a schematic cross-sectional view of a state in which the operation of tying a knot is repeated while moving the electrode cloth and the conductive cloth in a predetermined direction. It is a figure. FIG. 7A is a schematic cross-sectional view schematically showing an example of the contact state between the first electrode cloth and the conductive cloth, and FIG. 7B schematically shows another example of the contact state between the first electrode cloth and the conductive cloth. FIG. 7C is a schematic cross-sectional view schematically showing another example of the contact state between the first electrode cloth and the conductive cloth. FIG. 8 is a schematic plan view showing an example of the pressure sensor of the first embodiment, and is a diagram showing a state in which a controller is connected. FIG. 9A is a schematic plan view showing an example of the pressure holding portion of the pressure sensor of the first embodiment, and FIG. 9B is a schematic side view showing an example of the pressure holding portion of the pressure sensor of the first embodiment. It is a figure. FIG. 10A is a schematic plan view showing another example of the pressure holding portion of the pressure sensor of the first embodiment, and FIG. 10B is a schematic showing an example of the pressure holding portion of the pressure sensor of the first embodiment. It is a side view of. FIG. 11 is a schematic perspective view showing an example of a pressure sensor according to a second embodiment of the present invention. FIG. 12 is a schematic plan view showing an example of the pressure sensor of the second embodiment. FIG. 13A is a schematic front view showing an example of the pressure sensor of the second embodiment, and FIG. 13B is a schematic side view showing an example of the pressure sensor of the second embodiment. FIG. 14 is a schematic plan view showing an example of the pressure sensor of the second embodiment, and is a view showing a state in which a controller is attached. FIG. 15A is a resistance characteristic graph illustrating the relationship between pressure and resistance in the intersection region of the pressure sensor, and FIG. 15B is a resistance characteristic graph illustrating the relationship between pressure and resistance in the intersection region of the pressure sensor. is there. FIG. 16A is a resistance characteristic graph illustrating the relationship between pressure and resistance in the intersection region of the pressure sensor, and FIG. 16B is a resistance characteristic graph illustrating the relationship between pressure and resistance in the intersection region of the pressure sensor. is there. FIG. 17 is a pressure-sensitive characteristic graph illustrating the relationship between pressure and conductance in the intersection region of the pressure-sensitive sensor of the present embodiment.

(First Embodiment)
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic perspective view showing an example of the pressure sensor 1 of the first embodiment. FIG. 2 is a schematic plan view showing an example of the pressure sensor 1 of the present embodiment. FIG. 3A is a schematic front view showing an example of the pressure sensor of the first embodiment, and FIG. 3B is a schematic side view showing an example of the pressure sensor of the first embodiment. For convenience of explanation, the cover cloth, signal wiring, etc. are omitted in FIG. In all the drawings for explaining the embodiment, members having the same function may be designated by the same reference numerals, and the repeated description thereof may be omitted.

Here, in order to make it easier to explain the positional relationship of each part of the pressure sensor 1, the directions are indicated by the arrows X, Y, and Z in the figure. When the pressure sensor 1 is actually used, it is not limited to these directions, and there is no problem in using it in any direction. It should be noted that the first main surface 2a and the second main surface 2b are surfaces opposite to each other and show a relative positional relationship, and the physical orientation is not limited. The first main surface 2a can be read as, for example, an upper surface or a surface. Further, the second main surface 2b can be read as, for example, the lower surface or the back surface.

As shown in FIGS. 1, 2, 3A, and 3B, the pressure-sensitive sensor 1 has a sheet portion 2 (conductive cloth) made of a rectangular conductive cloth and a first main surface 2a of the conductive cloth 2. The first electrode portion 3 (first electrode cloth) made of a plurality of strip-shaped conductive cloths arranged at 1 interval 2c, and the second main surface 2b of the conductive cloth 2 in a direction intersecting with the first electrode cloth 3. A second electrode portion 4 (second electrode cloth) composed of a plurality of strip-shaped conductive cloths arranged at intervals of 2d, a non-conductive suture thread 5, and a first electrode cloth 3 and a second electrode cloth 4 at predetermined positions. A pressure holding unit 8 is provided which holds the electrodes at a predetermined pressure in the compression direction close to each other. Here, the first electrode cloth 3 is arranged substantially in parallel on the first main surface 2a of the conductive cloth 2, and the second electrode cloth 4 is arranged substantially in parallel on the second main surface 2b of the conductive cloth 2. The second electrode cloth 4 is arranged so as to be substantially orthogonal to the first electrode cloth 3. The conductive cloth 2, the first electrode cloth 3, and the second electrode cloth 4 are not limited to a square shape, and may have a rounded square shape or an elliptical shape.

As shown in FIGS. 1 and 2, the pressure holding portion 8 is arranged in the intersecting region V1 at the two corners on one end side of the intersecting regions V1 at the four corners, and the feeling of the position where the pressure holding portion 8 is arranged is felt. It is configured to correct or calibrate the pressure distribution at a position different from that of the pressure holding unit 8 depending on the pressure value.

As an example, the pressure holding portion 8 is a clip made of a U-shaped constant elastic body, as shown in FIGS. 9A and 9B. Further, as an example, the pressure holding portion 8 is a clothespin-shaped clip provided with a coil spring 81, as shown in FIGS. 10A and 10B. As an example, the material of the pressure holding portion 8 is polybutylene terephthalate (PBT), acrylonitrile-butadiene-styrene copolymer synthetic resin (ABS), polyacetal (POM), polymethylmethacrylate resin (PMMA), liquid crystal polymer (LCP). Examples thereof include insulating resins such as, stainless steel, nickel alloys, constant elastic metals such as Elimba with an insulating coating, glass, and other known constant elastic bodies.

According to this embodiment, there are abnormalities such as deformation of the pressure-sensitive part due to compression set, contact resistance between the electrode part and the pressure-sensitive part, changes in the usage environment such as temperature and humidity, and water immersion in the pressure-sensitive part. By treating the pressure-sensitive value of the pressure-holding unit 8 as a reference, correction or calibration can be easily performed while maintaining and improving the reproducibility of the pressure-sensitive value. Since the pressure holding portion 8 is arranged at a position deviated from the center of contact with the body, the measurement of biological information can be performed without any trouble even in the case of the thick pressure holding portion 8. As a configuration other than the above, when the pressure holding portion 8 is arranged in the crossing region V1 of one corner of the crossing regions V1 of the four corners, the pressure holding portion 8 is located in the crossing region V1 of the three corners of the crossing regions V1 of the four corners. When arranged, the pressure holding portion 8 may be arranged in the intersection region V1 at the four corners among the intersection regions V1 at the four corners.

Here, in the pressure-sensitive sensor 1, as shown in FIG. 4, the second electrode cloth 4 is made of a conductive cloth by the suture 5 at the position of the first gap 3a between the first electrode cloth 3 and the first electrode cloth 3. It is sewn on 2. Further, as shown in FIG. 5, the first electrode cloth 3 is sewn to the conductive cloth 2 by the suture thread 5 at the position of the second gap 4a between the second electrode cloth 4 and the second electrode cloth 4. .. Then, in a plan view, the intersection region V1 between the first electrode cloth 3 and the second electrode cloth 4 is formed in a matrix arrangement. In FIGS. 1 and 2, the hatched rectangular region is illustrated as an intersecting region V1.

In the example of FIG. 2, the suture thread 5 is sewn so as to surround the intersecting region V1. Moreover, the suture thread 5 is sewn at the outer positions of the four corners of the intersection region V1. According to this configuration, the leakage current from the crossing region V1 to the other crossing region V1 is reduced by sewing the suture thread 5, so that the S / N ratio of the detection signal output in response to the pressing force is improved. it can.

Then, as shown in FIG. 4, the portion of the first electrode cloth 3 where the suture thread 5 is sewn is recessed due to the tension of the suture thread 5. Further, as shown in FIG. 5, the portion of the second electrode cloth 4 where the suture thread 5 is sewn is recessed due to the tension of the suture thread 5. According to this configuration, a dead band is formed in the sewn portion by tightening the suture thread 5 in the vertical direction by sewing, and since the dead band is formed, the fluctuation of the resistance value in the portion other than the intersection region V1 can be suppressed. The S / N ratio of the detection signal output corresponding to the pressure can be improved. As a configuration other than the above, the suture thread 5 may be sewn at the positions of the four corners of the intersection region V1, and in this case as well, the same effect as the configuration shown in FIG. 4 can be expected.

6A, 6B, and 6C are schematic cross-sectional views illustrating a procedure for sewing the first electrode cloth 3 and the conductive cloth 2 with a sewing machine. As an example, in the case of lockstitching, a knot is formed by passing the bobbin thread 5 through the loop-shaped upper thread 5 penetrating the first electrode cloth 3 and the conductive cloth 2 by a sewing machine (FIG. 6A), and pulling up the knot. A knot is arranged between the first electrode cloth 3 and the conductive cloth 2 (FIG. 6B), and the work of tying the knot is repeated while moving the first electrode cloth 3 and the conductive cloth 2 in a predetermined direction to sew. (Fig. 6C). When sewing the second electrode cloth 4 and the conductive cloth 2 with a sewing machine, the sewing procedure is the same as that shown in FIGS. 6A, 6B, and 6C.

In the present embodiment, the width of the first electrode cloth 3 in the lateral direction is larger than the width of the first interval 2c in the lateral direction, and the width of the second electrode cloth 4 in the lateral direction is the second interval 2d. It is larger than the width in the lateral direction. According to this configuration, the leakage current from the adjacent measurement points is reduced, so that the S / N ratio of the detection signal output in response to the pressing force can be improved. The width of the first electrode cloth 3 in the lateral direction and the width of the second electrode cloth 4 in the lateral direction are, for example, 10 to 100 [mm], respectively. Further, the width of the first interval 2c in the lateral direction and the width of the second interval 2d in the lateral direction are 1 to 10 [mm], respectively, as an example.

In the present embodiment, the thickness of the conductive cloth 2 is smaller than the width of the first interval 2c in the lateral direction, and the thickness of the conductive cloth 2 is smaller than the width of the second interval 2d in the lateral direction. According to this configuration, the leakage current from the adjacent measurement points is reduced, so that the S / N ratio of the detection signal output in response to the pressing force can be improved. The thickness of the conductive cloth 2 is 0.3 to 0.6 [mm] as an example. The thickness of the first electrode cloth 3 and the thickness of the second electrode cloth 4 are 0.2 to 0.6 [mm] as an example.

The electrode in the first electrode cloth 3 may be formed only on the surface of the conductive cloth 2 facing the first main surface 2a, and in this case, the cost of the electrode material and the manufacturing cost can be suppressed. Alternatively, the electrodes in the first electrode cloth 3 may be formed on the upper surface and the lower surface of the first electrode cloth 3, and may be formed over the entire circumference of the first electrode cloth 3. In this case, either the upper surface or the lower surface of the first electrode cloth 3 may be superposed on the conductive cloth 2, which facilitates manufacturing. Alternatively, the electrodes in the first electrode cloth 3 may be formed so as to conduct in the thickness direction of the first electrode cloth 3, and in this case, the reliability of the conduction of the electrodes can be enhanced.

The electrode in the second electrode cloth 4 may be formed only on the surface of the conductive cloth 2 facing the second main surface 2b, and in this case, the cost of the electrode material and the manufacturing cost can be suppressed. Alternatively, the electrodes in the second electrode cloth 4 may be formed on the upper surface and the lower surface of the second electrode cloth 4, and may be formed over the entire circumference of the second electrode cloth 4. In this case, either the upper surface or the lower surface of the second electrode cloth 4 may be superposed on the conductive cloth 2, which facilitates manufacturing. Alternatively, the electrodes in the second electrode cloth 4 may be formed so as to conduct in the thickness direction of the second electrode cloth 4, and in this case, the reliability of the conduction of the electrodes can be enhanced.

7A, 7B, and 7C are enlarged views of a portion P1 surrounded by a broken line in FIG. 3A, and is a schematic cross-sectional view schematically showing an example of a contact state between the first electrode cloth 3 and the conductive cloth 2. Is. Here, the first conductive particles 11 are conductive carbon black, and the second conductive particles 12 are conductive metal particles 12a and conductive carbon black 12b. The conductive carbon black 11 is adhered to the conductive cloth 2 by the binder resin 13a, and the conductive metal particles 12a and the conductive carbon black 12b are adhered to the first electrode cloth 3 by the binder resin 13b. .. The contact state between the second electrode cloth 4 and the conductive cloth 2 is the same as the contact state shown in FIGS. 7A, 7B, and 7C. That is, the first electrode cloth 3 and the second electrode cloth 4 are coated with the second conductive particles 12 having higher electrical conductivity than the first conductive particles 11.

In this embodiment, the conductive cloth 2 is conductive in the thickness direction, the longitudinal direction, and the lateral direction due to the structure of the first conductive particles 11 (not shown). Further, due to the structure of the conductive metal particles 12a and the conductive carbon black 12b, the first electrode cloth 3 is conductive in the thickness direction, the longitudinal direction, and the lateral direction (not shown). The second electrode cloth 4 is the same as that of the first electrode cloth 3.

In the present embodiment, the conductive carbon black 11 (12b) is one or more of Ketjen black, acetylene black, channel black, and furnace black having an average primary particle size of 100 nm or less. According to this configuration, the required resistance value can be obtained with a small amount of addition, so that the conductive cloth has excellent scratch resistance and flexibility.

Furness black is produced by a furnace method in which oil or gas is incompletely burned in a high temperature gas to obtain conductive carbon black. Furnace black is suitable for mass production in manufacturing, and it is easy to control the particle size and structure.

Channel black is produced by the channel method, which is obtained by burning natural gas and scraping what is deposited on channel steel. Channel black is suitable for coating because it has many surface functional groups.

Acetylene black is produced by the acetylene method obtained by thermally decomposing acetylene gas. Acetylene black has high conductivity and few impurities.

Ketjen black is roughly manufactured by the oil furnace method in which oil with few impurities is incompletely burned in a high-temperature gas to obtain conductive carbon black. After separating the by-product gas, the precursor is granulated and dried. Is manufactured. Unlike other conductive carbon blacks, Ketjen black has a hollow shell-like structure, so it exhibits higher conductivity than acetylene black.

As an example, Lion Specialty Chemicals Co., Ltd.'s Ketjen Black EC300J has a BET specific surface area catalog value of 800 [m ² / g], and Ketjen Black EC600JD has a BET specific surface area catalog value of 1270 [m ² / g]. g] or more, both of which are 10 times or more the BET specific surface area of standard acetylene black. As a result, high conductivity can be obtained with a small amount of addition, so that the conductive cloth has excellent scratch resistance and flexibility.

As shown in FIG. 7A, the first electrode cloth 3 and the conductive cloth 2 are in a state where the outer diameter size of the first conductive particle 11 and the outer diameter size of the second conductive particle 12 are substantially the same size. This is the best mode that minimizes the contact resistance with. In the example of FIG. 7A, the contact area between the first electrode cloth 3 and the conductive cloth 2 is maximized to sufficiently secure the required contact area, and the resistance value of the first electrode cloth 3 is the conductive cloth 2. Since the value is appropriately smaller than the resistance value, it is possible to reduce variations in the resistance value and crosstalk depending on the measurement position. The second electrode cloth 4 is the same as that of the first electrode cloth 3.

As shown in FIG. 7B, the state in which the outer diameter size of the first conductive particle 11 is 0.5 times or more and 2.0 times or less the outer diameter size of the second conductive particle 12 This is a better mode in which the contact resistance between the first electrode cloth 3 and the conductive cloth 2 is an appropriately small value. In the example of FIG. 7B, most of the second conductive particles 12 of the first electrode cloth 3 and most of the first conductive particles 11 of the conductive cloth 2 come into contact with each other to secure a necessary contact area, so that the measurement position is obtained. It is possible to reduce the variation in resistance value and crosstalk due to. The second electrode cloth 4 is the same as that of the first electrode cloth 3.

As shown in FIG. 7C, the state in which the outer diameter size of the first conductive particle 11 is 2.0 times or less and 0.5 times or more the outer diameter size of the second conductive particle 12 This is a better mode in which the contact resistance between the first electrode cloth 3 and the conductive cloth 2 is an appropriately small value. In the example of FIG. 7C, most of the second conductive particles 12 of the first electrode cloth 3 and most of the first conductive particles 11 of the conductive cloth 2 come into contact with each other to secure a necessary contact area, so that the measurement position is obtained. It is possible to reduce the variation in resistance value and crosstalk due to. The second electrode cloth 4 is the same as that of the first electrode cloth 3.

As shown in FIGS. 7A, 7B, and 7C, in this embodiment, the average primary particle size of the second conductive particle 12 is 0.5 times or more based on the average primary particle size of the first conductive particle 11. It is within the range of 2.0 times or less. According to this configuration, the contact area between the first electrode cloth 3 and the conductive cloth 2 and the contact area between the second electrode cloth 4 and the conductive cloth 2 can be increased to stabilize the contact state.

In this embodiment, the weight of the first conductive particles 11 is 5% or less based on the weight of the conductive cloth 2. According to this configuration, the conductive cloth 2 has excellent scratch resistance and flexibility, and the material cost can be reduced.

In this embodiment, the conductive cloth 2 is coated with a mixture of the first conductive particles 11 and the binder resin 13a having a breaking elongation of 100% or more. Further, a mixture of the second conductive particles 12 and the binder resin 13b having a breaking elongation of 100% or more is coated on the first electrode cloth 3. Moreover, a mixture of the second conductive particles 12 and the binder resin 13b having a breaking elongation of 100% or more is coated on the second electrode cloth 4. According to this configuration, stable pressing force can be measured while taking advantage of the flexibility of the conductive cloth 2, the first electrode cloth 3, and the second electrode cloth 4.

In this embodiment, the conductive cloth 2, the first electrode cloth 3 and the second electrode cloth 4 are all woven fabrics, or the conductive cloth 2, the first electrode cloth 3 and the second electrode cloth 4 are all knitted fabrics. .. According to this configuration, it becomes a pressure sensor 1 having excellent elasticity, and it becomes a pressure sensor 1 capable of measuring a wide range of pressure distribution with a large size corresponding to the body while having flexibility with little discomfort to the body. ..

The first conductive particles 11 are adhered to the surface of the base cloth and the fibers of the conductive cloth 2 by the binder resin 13a. Further, the second conductive particles 12 are adhered to the surface of the base cloth and the fibers of the first electrode cloth 3 by the binder resin 13b. Then, the second conductive particles 12 are adhered to the surface of the base cloth and the fibers of the second electrode cloth 4 by the binder resin 13b.

As an example, in the conductive cloth 2, the base cloth made of fibers is coated with conductive carbon black (first conductive particles 11) and a binder resin 13a. As an example, in the first electrode cloth 3 and the second electrode cloth 4, conductive metal particles (second conductive particles 12) and a binder resin 13b are coated on a base cloth made of fibers. As an example, the first electrode cloth 3 and the second electrode cloth 4 are made of the same material.

In the present embodiment, the first electrode cloth 3 and the second electrode cloth 4 are coated with conductive metal particles, and the conductive cloth 2 is coated with conductive carbon black. The surface resistance of the electrode cloth 3 and the second electrode cloth 4 are both smaller than the surface resistance of the conductive cloth 2 by two orders of magnitude or more. According to this, since the influence of the resistance in the length direction of the first electrode cloth 3 and the second electrode cloth 4 is reduced, the S / N ratio of the detection signal output corresponding to the pressing force can be improved. That is, the influence of the measurement resistance in the intersection region V1 which is the pressure sensitive portion can be almost ignored. Moreover, the conductive cloth 2 having excellent dispersion stability can be formed by the conductive carbon black which is cheaper than the conductive metal particles. Further, the variation in the resistance value depending on the measurement position can be reduced, and the crosstalk between the crossing region V1 and the crossing region V1 can be reduced.

As an example, the base cloth is made of synthetic fibers such as nylon, polyester, rayon, acrylic and polyamide, and natural fibers such as cotton and linen. In the medical field, since it is assumed that the autoclave sterilization treatment is performed, these fibers having high resistance to the autoclave sterilization treatment are preferable.

The base cloth is, for example, a woven fabric, a knitted fabric, or a non-woven fabric. The thickness of the threads or fibers constituting the base fabric is, for example, 50 to 200 denier. When the base cloth is a knitted fabric or a non-woven fabric, the contact area with the body can be increased and the contact resistance can be lowered. When the base cloth is a knitted fabric, the elasticity is larger than that of a woven fabric or a non-woven fabric, which is excellent.

The first conductive particle 11 is made of conductive carbon black as an example, and is, for example, Ketjen black. Conductive carbon black has a branched structure structure, has a low resistance value due to the tunnel effect, and can be obtained at a low cost as compared with precious metals and conductive polymer compounds. In particular, Ketjen Black is a conductive cloth having excellent scratch resistance and flexibility because the required resistance value can be obtained with a small amount of addition.

The second conductive particle 12 is composed of, for example, a conductive metal powder, a conductive metal fiber, a conductive polymer compound, a conductive carbon black, or a mixture thereof. The conductive metal is, for example, gold (Au), silver (Ag), copper (Cu), nickel (Ni), aluminum (Al), and other known conductive metals. As an example, the conductive polymer compound is poly (3,4-ethylenedioxythiophene) (PEDOT), poly (4-styrene sulfonic acid) -doped poly (3,4-ethylenedioxythiophene) (PEDOT /). PSS), tetracyanoquinodimethane (TCNQ), polypyrrole (PPy), polyaniline (PANI), polythiophene (PT), or known conductive polymer compounds.

The binder resin 13a and the binder resin 13b are made of a thermoplastic resin, a thermosetting resin, or a photocurable resin as an example. The binder resin 13a and the binder resin 13b are, for example, polyamide (PA), polycarbonate (PC), polyethylene terephthalate (PET), polyurethane (PU), polyester (PEs), or known synthetic resins.

As the coating, a dipping method, a spray coating method, a roll coating method, a bar coating method, an electrodeposition method, another known coating method, or a combination of these coating methods can be applied.

As an example, the suture thread 5 is made of synthetic fibers such as nylon, polyester, rayon, acrylic and polyamide, and natural fibers such as cotton and linen. The thickness of the suture 5 is, for example, 20 to 200 denier.

Sewing is, for example, a sewing machine or hand-sewn. As an example, lockstitch, chain stitch, overlock stitch, flat stitch, and other known sewing methods are applied to the sewing. When sewing is lockstitching, on both the first main surface 2a (front side) and the second main surface 2b (back side), the portion where the suture thread 5 is sewn becomes a non-stretchable seam, and a dead zone is formed. Since fluctuations in resistance values at locations other than the intersection region V1 are suppressed, the intersection region V1 is formed in a matrix arrangement, and it becomes easy to function as an independent pressure cell for individually extracting electrical signals.

FIG. 8 is a schematic plan view showing an example of the pressure sensor 1 of the first embodiment, and is a view showing a state in which the controller 7 is connected. The controller 7 includes a signal wiring switching circuit, a signal detector, an A / D converter, a semiconductor memory, an arithmetic circuit, and a CPU that controls these.

In the pressure-sensitive sensor 1, signal lines are connected to the ends of the plurality of first electrode cloths 3b and the plurality of second electrode cloths 4b in the longitudinal direction, and the frequency is set as an example by a switching circuit built in the controller 7. Scanned at 10 to 100 [Hz], the resistance values of the intersecting regions V1 formed in the matrix arrangement are individually detected by the signal detector on the order of millisecond, A / D converted by the A / D converter, and the semiconductor. The data is stored in the memory, calculated by the arithmetic circuit, and finally displayed on the external display device as the pressure value or the pressure distribution, or the pressure value and the pressure distribution. As an example, a personal computer having a built-in interface board for signal connection with the pressure sensor 1 can be applied to the controller 7 and the display device.

In this embodiment, the number of [m] number of first electrode cloths 3 arranged on the first main surface 2a of the conductive cloth 2 at the first interval 2c and the first electrode cloth 3 on the second main surface 2b of the conductive cloth 2 A [n] number of second electrode cloths 4 arranged at a second interval 2d in a direction intersecting with the first electrode cloth 3 are provided, and an intersection region V1 between the first electrode cloth 3 and the second electrode cloth 4 is formed in a matrix arrangement. .. Here, [m] and [n] are natural numbers of 2 or more, respectively, and in the example of FIG. 8, m = 5 and n = 6.

In this embodiment, a resistance value which is an average value of resistances in the thickness direction of the intersecting region V1 in a state where an external force of 50 [mmHg] is applied in the compression direction in which the first electrode cloth 3 and the second electrode cloth 4 approach each other. The resistance value Re [Ω], which is the average value of the resistances in the longitudinal direction of the two intersecting regions V1 and V1 adjacent to each other in the longitudinal direction with respect to Rc [Ω], satisfies the following equation (1).

[Number 1]
1 <Re <(Rc / (m + n)) ... (1)

As shown in FIG. 8, when the electrode pitch 3c of each first electrode cloth 3 in the row direction and the electrode pitch 4c of each second electrode cloth 4 in the column direction are equal, the above equation (1) is obtained.

On the other hand, when the electrode pitch 3c of each first electrode cloth 3 and the electrode pitch 4c of each second electrode cloth 4 are different, the electrode resistance value R1 [Ω] at the electrode pitch 3c of each first electrode cloth 3 in the row direction. ] And the electrode resistance value R2 [Ω] at the electrode pitch 4c of each second electrode cloth 4 in the column direction, and the resistance value Re [Ω] is calculated by the following equation (2).

[Number 2]
Re = (m x R1 + n x R2) / (m + n) ... (2)

15A, 15B, 16A, and 16B are resistance characteristic graphs illustrating the relationship between pressure and resistance in the intersection region of the pressure sensor.

For example, when the first conductive particles are precious metal fine particles, the resistance value Re [Ω] is considerably smaller than 1 [Ω] (Re [Ω] << 1 [Ω]). In this case, as shown in FIG. 15A, the resistance characteristic graph of (11) and the resistance characteristic graph of (m, n) in the intersection region formed by the matrix arrangement of (m, n) are in agreement. However, the cloth must be plated with conductive noble metal particles, which greatly increases the material cost and makes it difficult to manufacture a large-sized pressure-sensitive sheet.

As an example of this embodiment, the first conductive particle 11 is conductive carbon black, and the resistance value Re [Ω] is set to a value larger than 1 [Ω] (1 [Ω] <Re [Ω]). Further, the second conductive particle 12 is a mixture of the conductive metal particle 12a and the conductive carbon black 12b, and the resistance value Re [Ω] is divided by the resistance value Rc [Ω] by (m + n). The value is considerably smaller than the value (Re [Ω] << (Rc [Ω] / (m + n))). In this case, as shown in FIG. 15B, the resistance characteristic graph of (1, 1) and the resistance characteristic graph of (m, n) in the intersection region formed by the matrix arrangement of (m, n) are shown in FIG. 15A. Similar to the graph in, it almost matches. Then, in the vicinity of the pressing force of 50 [mmHg] or in the range of the pressing force of 50 [mmHg] or more, the resistance characteristic graphs are substantially the same at any position of the intersecting region formed by the matrix arrangement.

According to this configuration, it is possible to measure the pressure stably while taking advantage of the flexibility of the cloth, and it is possible to make the size of the pressure distribution over a wide range measurable, and the configuration is highly productive while suppressing the material cost. .. Moreover, since the surface resistance of the strip-shaped electrodes (first electrode cloth 3 and second electrode cloth 4) arranged above and below the conductive cloth 2 is two orders of magnitude smaller than the surface resistance of the conductive cloth 2, each intersection. The measurement accuracy of the pressing force in the region V1 can be improved.

As an example of this embodiment, the first conductive particle 11 is conductive carbon black, and the resistance value Re [Ω] is set to a value considerably larger than 1 [Ω] (1 [Ω] << Re [Ω]. ), And the second conductive particle 12 is a mixture of the conductive metal particle 12a and the conductive carbon black 12b, and the resistance value Re [Ω] is set to the resistance value Rc [Ω] by (m + n). The value is smaller than the divided value (Re [Ω] <(Rc [Ω] / (m + n))). In this case, as shown in FIG. 16A, the resistance characteristic graph of (1, 1) and the resistance characteristic graph of (m, n) in the intersection region formed by the matrix arrangement of (m, n) are shown in FIG. 15A. And, as compared with the graph of FIG. 15B, the resistance value varies. In this case, since the variation of each resistance value is within twice, it can be used as a pressure-sensitive sensor by calibrating in each intersection region.

For example, the resistance value Re [Ω] is set to a value larger than the value obtained by dividing the resistance value Rc [Ω] by (m + n) (Re [Ω]> (Rc [Ω] / (m + n))). In this case, as shown in FIG. 16B, the resistance characteristic graph of (1, 1) and the resistance characteristic graph of (m, n) in the intersection region formed by the matrix arrangement of (m, n) are shown in FIG. 15B. And the graph of FIG. 16A has a large variation in resistance value. In this case, since the variation of each resistance value exceeds twice, it is difficult to use it as a pressure-sensitive sensor even if it is calibrated in each intersection region.

Subsequently, another example of the pressure sensor 1 of the first embodiment will be described below.

FIG. 11 is a schematic plan view showing an example other than the above of the pressure sensor 1 of the present embodiment. In this example, the stitches of the suture thread 5 are provided at a plurality of places in the intersection region V1 at the two corners on one end side of the intersection region V1 at the four corners, and the suture thread 5 provides the first electrode cloth 3 and the second electrode. A pressure holding portion 8 is formed which holds the cloth 4 at a predetermined pressure in the compression direction close to each other. According to this configuration, the pressure sensor 1 has a small thickness, and the material cost can be suppressed. As a configuration other than the above, when the pressure holding portion 8 is arranged in the crossing region V1 of one corner of the crossing regions V1 of the four corners, the pressure holding portion 8 is located in the crossing region V1 of the three corners of the crossing regions V1 of the four corners. When arranged, the pressure holding portion 8 may be arranged in the intersection region V1 at the four corners among the intersection regions V1 at the four corners.

(Second embodiment)
FIG. 12 is a schematic plan view showing an example of the pressure sensor 1 of the second embodiment. FIG. 13A is a schematic front view showing an example of the pressure sensor 1 of the second embodiment, and FIG. 13B is a schematic side view showing an example of the pressure sensor 1 of the second embodiment. For convenience of explanation, the cover cloth, signal wiring, and the like are omitted in FIG. 12 and the like. In the second embodiment, the differences from the first embodiment will be mainly described.

The present embodiment includes one first electrode cloth 3 arranged on the first main surface 2a of the conductive cloth 2 and one second electrode cloth arranged on the second main surface 2b of the conductive cloth 2. The first electrode cloth 3 has a plurality of first electrodes 3b formed at the first interval 2c, and the second electrode cloth 4 has a plurality of second electrodes 4b formed at the second interval 2d and the second electrode. 4b is arranged so as to intersect the first electrode 3b, and the intersection region V1 between the first electrode 3b and the second electrode 4b is formed in a matrix arrangement.

In the present embodiment, the pressure holding portion 8 is arranged in the intersecting regions V1 at the four corners, and the pressure held by the suture thread 5 at a predetermined pressure in the compression direction in which the first electrode cloth 3 and the second electrode cloth 4 approach each other. The holding portion 8 is formed.

In the present embodiment, the width of the first electrode 3b in the lateral direction is larger than the width of the first interval 2c in the lateral direction, and the width of the second electrode 4b in the lateral direction is the lateral width of the second interval 2d. Greater than the width of the direction. According to this configuration, the leakage current from the adjacent measurement points is reduced, so that the S / N ratio of the detection signal output in response to the pressing force can be improved. The width of the first electrode 3b in the lateral direction and the width of the second electrode 4b in the lateral direction are, for example, 10 to 100 [mm], respectively. Further, the width of the first interval 2c in the lateral direction and the width of the second interval 2d in the lateral direction are 1 to 10 [mm], respectively, as an example.

In the present embodiment, the thickness of the conductive cloth 2 is smaller than the width of the first interval 2c in the lateral direction, and the thickness of the conductive cloth 2 is smaller than the width of the second interval 2d in the lateral direction. According to this configuration, the leakage current from the adjacent measurement points is reduced, so that the S / N ratio of the detection signal output in response to the pressing force can be improved. The thickness of the conductive cloth 2 is 0.3 to 0.6 [mm] as an example. The thickness of the first electrode cloth 3 and the thickness of the second electrode cloth 4 are 0.2 to 0.6 [mm] as an example.

The first electrode 3b may be formed only on the surface of the first electrode cloth 3 facing the first main surface 2a of the conductive cloth 2, and in this case, the cost of the electrode material and the manufacturing cost can be suppressed. Alternatively, the first electrode 3b may be formed on the upper surface and the lower surface of the first electrode cloth 3, and in this case, whichever of the upper surface and the lower surface of the first electrode cloth 3 is overlapped with the conductive cloth 2. It is good and easy to manufacture. Alternatively, the first electrode 3b may be formed so as to conduct in the thickness direction of the first electrode cloth 3, and in this case, the reliability of the conduction of the electrodes can be enhanced.

The second electrode 4b may be formed only on the surface of the second electrode cloth 4 facing the second main surface 2b of the conductive cloth 2, and in this case, the cost of the electrode material and the manufacturing cost can be suppressed. Alternatively, the second electrode 4b may be formed on the upper surface and the lower surface of the second electrode cloth 4, and in this case, whichever of the upper surface and the lower surface of the second electrode cloth 4 is superposed on the conductive cloth 2. It is good and easy to manufacture. Alternatively, the second electrode 4b may be formed so as to conduct in the thickness direction of the second electrode cloth 4, and in this case, the reliability of the conduction of the electrodes can be enhanced.

In the second embodiment, the dimensions and the number of the first electrode cloth 3 and the second electrode cloth 4 are different from those in the first embodiment described above. Other sewing methods, sewing positions, first conductive particles 11, second conductive particles 12, and other components can be made in the same manner as in the first embodiment.

As an example other than the above, for example, the first electrode cloth 3 and the second electrode cloth 4 are made of a woven fabric. As the warp threads, for example, a plurality of conductive threads having a nylon core as a shell formed of silver plating and, for example, nylon insulating threads are arranged alternately. Further, the weft threads are woven in order, for example, a plurality of insulating threads made of nylon to form a single first electrode cloth 3 in which a plurality of striped electrodes are formed at predetermined intervals. Then, the second electrode cloth 4, which is the same as the first electrode cloth 3, is rotated by 90 ° in the horizontal direction to form a matrix electrode above and below the conductive cloth 2. Then, the first electrode cloth 3, the conductive cloth 2, and the second electrode cloth 4 are sewn by the suture thread 5 at a portion that does not include the intersecting region V1. According to this configuration, the pressure-sensitive sensor 1 having a high degree of freedom in size that maximizes the flexibility of the cloth can be obtained.

FIG. 14 is a schematic plan view showing an example of the pressure sensor 1 of the second embodiment, and is a view showing a state in which the controller 7 is connected. The controller 7 includes a signal wiring switching circuit, a signal detector, an A / D converter, a semiconductor memory, an arithmetic circuit, and a CPU that controls these.

The present embodiment includes one first electrode cloth 3 arranged on the first main surface 2a of the conductive cloth 2 and one second electrode cloth 4 arranged on the second main surface 2b of the conductive cloth 2. , The first electrode cloth 3 has [m] number of first electrodes 3b formed at the first interval 2c, and the second electrode cloth 4 has [n] number of second electrodes 4b formed at the second interval 2d. The second electrode 4b is arranged so as to intersect the first electrode 3b, and the intersection region V1 between the first electrode 3b and the second electrode 4b is formed in a matrix arrangement. Here, [m] and [n] are natural numbers of 2 or more, respectively, and in the example of FIG. 14, m = 5 and n = 6.

In this embodiment, a resistance value which is an average value of resistances in the thickness direction of the intersecting region V1 in a state where an external force of 50 [mmHg] is applied in the compression direction in which the first electrode cloth 3 and the second electrode cloth 4 approach each other. The resistance value Re [Ω], which is the average value of the resistances in the longitudinal direction of the two intersecting regions V1 and V1 adjacent to each other in the longitudinal direction with respect to Rc [Ω], satisfies the above equation (1).

As shown in FIG. 14, when the electrode pitch 3c of each first electrode cloth 3 in the row direction and the electrode pitch 4c of each second electrode cloth 4 in the column direction are equal, the above equation (1) is obtained.

On the other hand, when the electrode pitch 3c of each first electrode cloth 3 and the electrode pitch 4c of each second electrode cloth 4 are different, the electrode resistance value R1 [Ω] at the electrode pitch 3c of each first electrode cloth 3 in the row direction. ] And the electrode resistance value R2 [Ω] at the electrode pitch 4c of each second electrode cloth 4 in the column direction, and the resistance value Re [Ω] is calculated by the above equation (2). The resistance characteristics of the pressure-sensitive sensor are the same as the graphs in FIGS. 15A, 15B, 16A, and 16B described above.

Subsequently, a method for manufacturing the pressure-sensitive sensor 1 according to the present invention will be described below.

As an example, the manufacturing procedure of the pressure-sensitive sensor 1 includes a conductive cloth forming step of applying a dispersion liquid of the first conductive particles 11 made of conductive carbon black to the first base cloth to form the conductive cloth 2. Forming an electrode cloth for forming the first electrode cloth 3 and the second electrode cloth 4 by applying a dispersion liquid of the second conductive particles 12 having a higher electric conductivity than the first conductive particles 11 to the second base cloth. Have steps. As an example, the first conductive particle 11 is Ketjen black, the second conductive particle 12 is a mixture of the conductive metal particle 12a and the conductive carbon black 12b, and the electrode cloth forming step is the elongation at break. In the conductive cloth forming step, the binder resin 13a having a breaking elongation of 100% or more and the first conductive particles 11 are mixed and coated, and the binder resin 13b having a breaking elongation of 100% or more and the second conductive particles are used. The particles 12 are mixed and coated.

According to this configuration, the pressure-sensitive sensor can be manufactured by a simple coating operation without being restricted by the equipment size as in the plating equipment. Since conductive carbon black can be obtained at a lower cost than precious metals and conductive polymer compounds, high productivity can be obtained while suppressing material costs.

After the conductive cloth forming step and the electrode cloth forming step, the second electrode cloth 4 is provided by the non-conductive suture thread 5 at the position of the first gap 3a between the first electrode cloth 3 and the first electrode cloth 3. Is sewn to the conductive cloth 2, and the first electrode cloth 3 is sewn to the conductive cloth 2 by the suture thread 5 at the position of the second gap 4a between the second electrode cloth 4 and the second electrode cloth 4. It has a sewing step of forming an intersecting region V1 between the 1-electrode cloth 3 and the 2nd electrode cloth 4 in a matrix arrangement. Then, in the sewing step, the suture thread 5 is sewn with a sewing machine.

According to this configuration, the pressure-sensitive sensor 1 can be manufactured by a simple sewing operation without being restricted by the equipment size. Since the area of the electrode cloth to be sewn is smaller than the area of the conductive cloth, high productivity can be obtained while suppressing the material cost. Moreover, since the boundary of the crossing region V1 for detecting the pressing force is formed by sewing and each crossing region is formed in a matrix arrangement, the measurement accuracy of the pressing force in each crossing region V1 can be improved.

The pressure-sensitive sensor 1 manufactured in this manner can be applied to a bed, a bed mat, sheets, a mat, a cushion, a chair mat, a health mat, and a carpet as an example.

For example, by incorporating the pressure sensor 1 into a bed, a bed mat, sheets or a mat, it is possible to measure a person's sleeping appearance at bedtime and to promote turning over by adjusting the air pressure of the air mat to prevent pressure ulcers. It is also possible to measure heartbeat, respiration, etc. as a heartbeat sensor or respiration sensor by analyzing and calculating the pressure waveform of a predetermined portion.

For example, by incorporating the pressure sensor 1 into a cushion or chair mat, the posture can be corrected by measuring the sitting posture of a person, detecting the person leaving the seat to grasp the movement of the person, adjusting the air pressure of the air cushion, and the like. Can prevent stiff shoulders and back pain.

For example, by incorporating the pressure sensor 1 into a health mat or carpet, it is possible to customize shoes corresponding to the subject by measuring the walking posture of a person or measuring the foot pressure in a standing position. It is also possible to measure the weight of a person from the contact resistance, and it can also be applied to the measurement of lifestyle habits such as movement of a person in a room.

In general, in pressure distribution measurement in a chair or bed, the measurement range by the pressure sensor 1 can be sufficiently measured when the pressing force is 10 to 200 [mmHg]. The frequency of measurement by the pressure sensor 1 is high when the pressing force is around 50 [mmHg].

As an example other than the above, a capacitance type pressure sensor can be obtained in which the sheet portion 2 is made of a dielectric material and the capacitances of the first electrode portion 3 and the second electrode portion 4 are measured. In the case of a capacitance type pressure sensor, the sheet portion 2 is formed of, for example, an electrically insulating elastomer such as rubber or resin, which is an elastic material that can be easily elastically deformed in the thickness direction.

The correction or calibration of the pressure distribution in the above-described embodiment is carried out in response to environmental changes such as temperature and humidity. For example, when the sheet portion 2 is made of a dielectric material, the capacitance value tends to increase as the temperature and humidity rise. On the other hand, when the sheet portion 2 is made of a conductor, the resistance value tends to decrease as the temperature and humidity increase. If these data are stored in a database in advance in a state where they can be used as an information table for correction and calibration, the temperature and humidity can be predicted. Further, regarding an abnormal situation such as spilling water, in both cases where the sheet portion 2 is a dielectric and the sheet portion 2 is a conductor, between the electrodes of the first electrode portion 3 and the second electrode portion 4. Since a short circuit occurs, it is possible to warn that measurement is not possible by detecting an excessive current. Further, the deformation of the pressure-sensitive part due to the compression set is also abnormal when the capacitance value exceeds the preset range or the resistance value falls below the preset range. Can be warned.

[Example]
The conductive cloth 2 was formed by applying fine particles of Ketjen black as the first conductive particles 11 and a mixed solution of urethane resin as a binder and water to a nylon knitted fabric as the first base cloth. A mixture of silver fine particles 12a and conductive carbon black 12b as the second conductive particles 12 and a mixed solution of urethane resin as a binder and water are applied to a nylon knitted fabric as the second base cloth. The first electrode cloth 3 and the second electrode cloth 4 were formed. Then, by lock stitching of the sewing machine, the second electrode cloth 4 is sewn to the conductive cloth 2 with the nylon suture thread 5, and the first electrode cloth 3 is sewn to the conductive cloth 2 with the nylon suture thread 5. The intersection region V1 of the electrode cloth 3 and the second electrode cloth 4 is formed in a matrix arrangement, and the first electrode cloth is formed by the suture thread 5 at a plurality of locations in the intersection region V1 at one corner of the four corner intersection regions V1. A pressure-sensitive sensor 1 was prototyped by forming a pressure-holding portion 8 that holds the third and the second electrode cloth 4 at a predetermined pressure in the compression direction approaching each other.

FIG. 17 is a pressure-sensitive characteristic graph illustrating the relationship between the pressure due to the airbag and the conductance in the intersection region V1 (second row, second column) of the pressure-sensitive sensor 1 of the prototype. The vertical axis of the graph is conductance [μS], and the horizontal axis of the graph is pressure [mmHg].

As shown in FIG. 17, the conductance increases (the resistance value decreases) by pressurization, and the conductance decreases (the resistance value increases) by the depressurization. Due to the nature of the restoring force of the fibers, the graph has a hysteresis curve. When the same pressure is continuously applied, the conductance gradually increases (the resistance value decreases) according to the elapsed time (not shown).

As shown in FIG. 17, the conductance has the same inclination during pressurization and depressurization, and from this, it can be seen that highly reproducible measurement can be performed.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the present invention. Although the above-described embodiment has been described as a sheet portion 2 (conductive cloth) made of a conductive cloth, the present invention is not limited to this. For example, the sheet portion 2 may be formed of an electrically insulating elastomer such as rubber or resin, which is an elastic material that can be easily elastically deformed in the thickness direction.

The shape and size of the pressure sensitive sensor 1 may be appropriately changed according to the specifications of known beds, bed mats, sheets, mattresses, cushions, chair mats, health mats, carpets, and the like.

1 Pressure sensitive sensor 2 Sheet part (conductive cloth), 2a 1st main surface, 2b 2nd main surface, 2c 1st interval, 2d 2nd interval 3 1st electrode part (1st electrode cloth), 3a 1st gap, 3b 1st electrode 4 2nd electrode part (2nd electrode cloth), 4a 2nd gap, 4b 2nd electrode 5 Suture thread 7 Controller 8 Pressure holding part 11 1st conductive particles (conductive carbon black)
12 Second conductive particles (mixture of conductive metal particles and conductive carbon black)
12a Conductive metal particles, 12b Conductive carbon black 13a, 13b Binder resin V1 Intersection region

Claims (6)

A sheet portion made of a dielectric or a conductor, a first electrode portion arranged on the first main surface of the sheet portion, and a second electrode portion arranged on the second main surface of the sheet portion are provided. A plurality of first electrodes are formed in the first electrode portion at the first interval, a plurality of second electrodes are formed in the second electrode portion at the second interval, and the second electrode is the first electrode. It is arranged so as to intersect with the electrodes, and the intersecting region between the first electrode and the second electrode is formed in a matrix arrangement, or
A sheet portion made of a dielectric or a conductor, a plurality of first electrode portions arranged at first intervals on the first main surface of the sheet portion, and the first electrode portion on the second main surface of the sheet portion. A plurality of second electrode portions arranged at second intervals in the intersecting direction are provided, and the intersecting region between the first electrode portion and the second electrode portion is formed in a matrix arrangement.
At least one of the intersecting regions is provided with a pressure holding portion that holds the first electrode portion and the second electrode portion at a predetermined pressure in a compression direction approaching each other .
The pressure holding portion is arranged in at least one of the intersecting regions at the four corners, and the pressure at a position different from that of the pressure holding portion depends on the pressure sensitive value at the position where the pressure holding portion is arranged. A pressure-sensitive sensor characterized in that it is configured to correct or calibrate the distribution. Said pressure holding unit, the are arranged in a plurality of locations of the cross region, the pressure-sensitive sensor of claim 1, wherein varying the pressure of the pressure holding portions at each location. The pressure-sensitive sensor according to claim 1 or 2 , wherein the pressure holding portion has an elastic body that applies a predetermined pressure in the compression direction. The sheet portion, the first electrode portion, and the second electrode portion are all woven fabrics, or the sheet portion, the first electrode portion, and the second electrode portion are all knitted. The pressure-sensitive sensor according to any one of claims 1 to 3. The feeling according to claim 4 , wherein the first electrode portion is sewn to the seat portion by a suture, and the second electrode portion is sewn to the seat portion by the suture. Pressure sensor. The pressure-sensitive sensor according to claim 5 , wherein the suture is sewn to at least one of the intersecting regions at the four corners to form the pressure holding portion.

Images