JP2020177028A - Pressure sensor sheet - Google Patents

Abstract

To provide a pressure sensor sheet which solves the problem that conventional pressure sensor sheets are inadequate as test devices for measuring performance and the like, as they are not capable of measuring a ground contact pressure distribution of shear force applied from an oblique angle, and thus not capable of deriving a true state of contact with a ground surface.SOLUTION: A pressure sensor sheet disclosed herein has an insulating layer with gradation to reduce internal stress deformation that causes noise. Such an arrangement enhances detection sensitivity and results in more accurate measurement of shear force.SELECTED DRAWING: Figure 1

Description

The present invention relates to a pressure sensor sheet used in a device for measuring a ground contact state such as a tire or a shoe sole.

Conventionally, the invention disclosed in Patent Document 1 below is known as a method for measuring a ground contact state of a tire. The present invention comprises a substrate having a surface for grounding a tire, a pressure sensor sheet arranged on the surface of the substrate and having a plurality of pressure measurement points, a protective sheet covering the surface of the pressure sensor sheet, and the like. The pressure sensor sheet is an invention having a structure in which a resin whose electric resistance is reduced according to the amount of deformation when compressed between the first linear electrode and the second linear electrode is filled.

Then, the electric resistance of this resin decreases as the force for pressing the outer surface of the sheet increases. Therefore, the electric resistance between the first linear electrode and the second linear electrode is reduced by pressing the sheet at the intersection of the first linear electrode and the second linear electrode in a plan view. Therefore, by measuring the electric resistance, the force acting on the resin at the intersection can be measured, and the contact patch shape and the contact pressure distribution of the tire can be obtained.

Japanese Unexamined Patent Publication No. 2018-72041

However, only the components in the Z-axis direction (direction perpendicular to the linear electrode) can be detected by the force acting on the resin at the intersection, and the XY-axis direction (the direction in which the tire moves is the X-axis, which is perpendicular to it). The component whose direction is the Y axis) cannot be detected. That is, in the pressure sensor sheet having such a structure, only the contact pressure distribution in the Z-axis direction can be obtained, and for example, the contact pressure distribution of the stress (shear force) applied in the diagonal direction exerted by the tire on the contact patch is measured. It is not possible. Therefore, there is a problem that the true contact state between the tire and the contact patch is not measured, and the test device for measuring the performance of the tire is insufficient.

The present invention has been devised in view of the above circumstances, and is a pressure sensor sheet capable of calculating the stress (shearing force) applied in an oblique direction from above the protective layer, based on the first electrode. It is an invention in which the insulating layer formed between the electrode and the plurality of electrodes is made of an elastic body having predetermined characteristics, and can be used in a device for measuring a true ground contact state of a tire or a shoe sole.

That is, in the first embodiment of the present invention, the first electrode is formed on the substrate, the insulating layer is formed on the first electrode, the second electrode is formed on the insulating layer, and the second electrode is formed. A pressure sensor sheet having a protective layer formed on the surface of the pressure sensor sheet, wherein the insulating layer has gradation. A second embodiment of the present invention is a pressure sensor sheet in which the gradation of the insulating layer depends on any of the density, hardness, elastic modulus, and shear strength of the material.

A third embodiment of the present invention is a pressure sensor sheet in which the insulating layer is made of a foam. A fourth embodiment of the present invention is a pressure sensor sheet in which counterbore-like irregularities are formed on the insulating layer. A fifth embodiment of the present invention is a pressure sensor sheet in which the insulating layer is composed of a single layer. A sixth embodiment of the present invention is a pressure sensor sheet used in a device for measuring a ground contact state of any one of the tire, the sole, and the track point according to any one of the above.

In the pressure sensor sheet of the present invention, a first electrode is formed on a substrate, an insulating layer is formed on the first electrode, a second electrode is formed on the insulating layer, and a protective layer is formed on the second electrode. The pressure sensor sheet is characterized in that the gradation of the insulating layer depends on physical or chemical properties such as density, hardness, elastic coefficient, and shear strength of the material.

Therefore, since the internal stress strain generated in the insulating layer can be appropriately reduced, the load applied to the insulating layer by pressing can be reduced, and the durability of the insulating layer and other layers can be improved. In addition, since the internal stress strain that becomes noise is reduced, the detection sensitivity is improved, and as a result, the shearing force can be measured more accurately. This effect can be applied not only to the conventional ground pressure distribution in the Z-axis direction but also to the ground pressure distribution of stress (shear force) applied in the diagonal direction. As a result, pressure detection and shear force detection There is also an effect that can distinguish.

Further, the pressure sensor sheet of the present invention is characterized in that the insulating layer is made of a foam. Therefore, the density, hardness, elastic modulus, and shear strength of the material of the insulating layer can be controlled by setting an appropriate foam size and foam density, and an insulating layer with gradation can be easily obtained. effective. Further, the foam has the effect of improving the cushioning property, reducing the load applied to the insulating layer by pressing, and improving the durability of the insulating layer and other layers.

Further, the pressure sensor sheet of the present invention is characterized in that the insulating layer is formed with counterbore-like irregularities. Therefore, the density, hardness, elastic modulus, and shear strength of the material of the insulating layer can be controlled by setting an appropriate counterbore-like uneven shape, and the effect of easily forming an insulating layer with gradation can be obtained. is there.

Further, the pressure sensor sheet of the present invention is characterized in that the insulating layer is composed of a single layer. Therefore, since only one layer needs to be formed, there is an effect of improving productivity and stabilizing quality.

It is sectional drawing of the pressure sensor sheet of one Embodiment of this invention. It is sectional drawing of the pressure sensor sheet of one Embodiment of this invention which made the insulating layer have a gradation by the density | concentration of foam of foam. It is sectional drawing of the pressure sensor sheet of one Embodiment of this invention which made the insulating layer have a gradation by the size of the foam of foam. It is sectional drawing of the pressure sensor sheet of one Embodiment of this invention which provided the counterbore-like unevenness and made the insulating layer have gradation.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the pressure sensor sheet 1 of the present invention, the first electrode 20 is formed on the substrate 10, the insulating layer 30 is formed on the first electrode 20, and the second electrode 40 is formed on the insulating layer 30. The pressure sensor sheet is characterized in that a protective layer 50 is formed on the second electrode 40 and the insulating layer 30 has a gradation (FIG. 1).

The fact that the insulating layer 30 has gradation means that the insulating layer 30 is not a uniform film, but a film having a structure in which physical properties or chemical properties change stepwise in a certain direction (particularly, in the Z-axis direction in the present invention). It means that the number of gradation steps and the degree of shading are not particularly limited. However, in general, as the number of gradation stages and the degree of shading increase, all the properties change smoothly, which is a preferable mode.

Physical properties include properties unique to the material such as density, hardness, specific gravity, melting point, boiling point, specific heat, dielectric constant, magnetic permeability, magnetization rate, conductivity, refractive index, odor, and color, and elasticity. Shear strength, tensile fracture nominal strain, tensile strength, impact resistance, abrasion resistance, compressibility, compressive strength, bending strength, yield stress, tensile strength, etc. In addition, chemical properties are properties that, when there is another substance, reacts with it and tries to change into a new substance with different properties.

In particular, as the gradation of the insulating layer 30 of the present invention, physical properties such as material density, hardness, elastic modulus, and shear strength are preferable. It should be noted that the physical properties of the insulating layer 30 alone cannot be measured, for example, when the insulating layer 30 is a very thin film or when the insulating layer 30 is integrated with the substrate 10 or a plurality of second electrodes 40 and cannot be completely separated. In this case, the value measured on the condition that the insulating layer 30 occupies 90% or more of the total volume of the laminated body of the insulating layer 30 and the substrate 10 and the second electrode 40 is the insulating layer. It is a value of 30 physical properties.

As a method of giving gradation to the insulating layer 30 according to the density of the material, there is a method of forming the insulating layer 30 with a plurality of foam layers and gradually changing the concentration of the bubbles. That is, the insulating layer 30 has a three-layer structure of, for example, a foam layer, and a foaming agent is mixed and dispersed in different proportions with respect to the main material of the insulating layer 30 for each layer, and heat is applied to form the insulating layer 30. As a result, an insulating layer 30 made of foam having different concentrations of bubbles 32 is obtained (FIG. 2).

Further, there is also a method in which the insulating layer 30 is composed of a plurality of foam layers, and the size of the bubbles is changed stepwise to give gradation to the insulating layer 30. That is, the insulating layer 30 has a three-layer structure of, for example, a foam, and foaming agents having different sizes or components are mixed and dispersed in the insulating layer 30 for each layer, and heat is applied to form the insulating layer 30, respectively. An insulating layer 30 made of foams having different sizes of bubbles 32 can be obtained (FIG. 3).

In the above two cases, the insulating layer 30 is made of a three-layered foam, but it may be a single layer, two layers, or four or more layers. As a method of obtaining an insulating layer 30 having a single layer and gradation, a plurality of foaming agents having different specific gravities are mixed, dispersed and stirred, and the insulating layer 30 is provided to some extent according to the magnitude of the specific gravity of the foaming agents. It is advisable to apply heat to foam the material at the timing when it begins to separate in the material. From the viewpoint of productivity, it is preferable to form a single layer because the manufacturing process can be shortened (Fig. 3).

The size of the foam 32 of the foam is preferably in the range of 2 μm to 100 μm even when gradation is applied with the size of the foam 32. As a method for producing a foam to obtain the size of such bubbles 32, it is preferable to control the atmospheric pressure (outside air pressure) by reducing or pressurizing it to a constant pressure in the reaction process of vulcanization foaming. By controlling the range, it is possible to promote or inhibit the growth of bubbles during vulcanization and foaming, and it is possible to obtain a foam having a certain desired foaming ratio and a certain cell size. .. In addition, the range of the foaming ratio can be significantly widened, and a product having a desired foaming ratio can be obtained.

Examples of the foaming agent include a pyrolytic foaming agent such as azodicarbonamide and bicarbonate, and a heat-expandable microcapsule foaming agent in which chlorofluorocarbons and hydrocarbons are wrapped in a thermoplastic resin capsule. Examples of the foam molding method include bead foaming, batch foaming, press foaming, normal pressure secondary foaming, injection foaming, extrusion foaming, and foaming blow.

Among the foams, silicone foam whose material is composed of a silicone-based resin is preferable. It has the advantage that it has little elastic change due to temperature and can be measured at low temperatures, and because it has high durability, it can prevent breakage and deformation even if strain or stress due to large displacement is repeatedly applied. As a result, it can be used as a device for measuring the ground contact state in all fields, such as when measuring an object having a large load such as a tire, or when measuring an object having a small load such as a shoe sole.

Silicone foam is a foam in which silicone rubber is independently foamed or semi-independently foamed. As described above, a foaming agent is added to the silicone rubber and heated to foam, as well as a self-foaming reaction consisting of a two-component liquid silicone. Types etc. can be mentioned. As a method of producing the insulating layer 30 from the self-foaming reaction type silicone foam, a liquid silicone rubber raw material is sandwiched between two carrier sheets, and the silicone rubber raw material is vulcanized and foamed by passing it between calendar rolls to form a dispensing sheet shape. Calendar molding method, free foaming method in which liquid silicone rubber raw material is charged on a sheet in an unregulated manner and vulcanized and foamed, and cast molding in which silicone liquid raw material is poured into a mold and vulcanized and foamed. The law etc. can be mentioned.

Further, since polyethylene, polypropylene, polystyrene and the like generate elastic force suitable for the pressure sensor sheet by making them foams, when these synthetic resins are selected as the material of the insulating layer 30, they can be made into foams. preferable. When the insulating layer 30 is formed of a material unsuitable for foam, there is also a method of forming a counterbore-shaped recess 70 on the surface of the insulating layer 30 to form the insulating layer 30 having gradation.

That is, the insulating layer 30 has a three-layer structure in which the size or number of holes due to the counterbore-shaped recesses 70 decreases in order from the protective layer 50 side, and the density of the material of the insulating layer 30 in each layer increases from small to large. By changing stepwise, the insulating layer 30 has gradation (FIG. 4). In this case, the example in which the insulating layer 30 is composed of three layers is given, but it may be a single layer, two layers, or four or more layers. In order to obtain the insulating layer 30 having a gradation with a single layer, it is preferable to form a counterbore-shaped concave portion by a single pressing process with a jig processed into a counterbore-like convex shape finally obtained. From the viewpoint of productivity, it is preferable to form a single layer because the manufacturing process can be shortened.

The bubbles 32 and the counterbore-shaped recesses 70 formed in the insulating layer 30 have the bubbles 32 and the recesses of the insulating layer 30 when pressure or shearing force is applied to the insulating layer 30 and the protective layer 50 swells due to the reaction. The 70 has the effect of absorbing it and, as a result, reducing the swelling of the insulating layer 30, which has the effect of accurately measuring the pressure or shearing force. The size of the foam 32 and the counterbore-shaped recess 70 may be appropriately selected depending on the material and thickness of the insulating layer 30.

The material of the insulating layer 30 is preferably the above-mentioned silicone, polyethylene, polypropylene, or polystyrene resin, but other materials may be used. Examples include synthetic resin sheets having elastic force such as fluorine, urethane, epoxy, ethylene-vinyl acetate copolymer, and butadiene rubber, and elastic non-woven fabric sheets. The insulating layer 30 is not limited to a sheet formed by a general sheet molding method such as extrusion molding, and may be a coating layer formed by printing, a coater, or the like. The thickness may be appropriately selected in the range of 20 μm to 5 mm. Further, the insulating layer 30 is not limited to the foam, and may be a gel-like sheet such as a silicone gel or an elastomer sheet such as a silicone elastomer.

Silicone gel is a material that contains organopolysiloxane as the main component and turns into a gel after curing. It has the unique properties of silicone such as durability and high safety and hygiene, and low cross-linking such as flexibility, shock absorption and moisture resistance. It has properties that result from its density (the density of the network structure that chemically bonds the chain polymers to each other is low). There are mainly room temperature curing type and heat curing type, and the curing rate differs depending on the type of curing agent, increase / decrease in the amount of addition, temperature control, etc. A silicone hydrogel obtained by blending silicone with a hydrophilic gel such as polyvinylpyrrolidone or a polyvinyl chloride-based thermoplastic elastomer is also included in one of the silicone gels of the present invention.

As a method for producing the insulating layer 30 from the silicone gel, a catalyst having a curing promoting action and a silicone rubber material are added to the silicone gel material to make a compounding raw material, and various coaters such as a lip coater, a comma coater, a reverse coater, and a knife coater are used. Examples thereof include a method of forming a sheet with the above method and a method of applying a silicone gel material on a silicone rubber sheet prepared in advance with the various coaters and integrally molding the material.

Silicone elastomers include heat-curable silicone elastomers obtained by cross-linking a linear silicone rubber compound or liquid silicone rubber with a sulfide or catalyst, as well as other elastomers such as urethanes blended with silicone oil or reactive. There are thermoplastic silicone-modified elastomers copolymerized with silicone oil. Examples of the method for producing the insulating layer 30 from the silicon elastomer include rolling molding in which a reinforcing agent or a vulcanizing agent is added to the silicone raw material, mixed by stirring, and subjected to a rolling mill having a predetermined thickness to form a sheet. In addition, press molding that is poured into a predetermined mold and vulcanized by applying heat and pressure, extrusion molding that is made into a sheet by an extruder, calendar molding that is molded into a wide long sheet using a calendar roll, and a coating device are used. Examples thereof include coating molding, injection molding, and vulcanization molding in which a base material such as glass cloth is coated.

In addition to the catalyst, a stabilizer may be blended in these silicone resin-based elastic sheets. Examples of the catalyst include nitrogen-containing compounds such as triethylamine and triethylenediamine, metal salts such as potassium acetate, zinc stearate and tin octylate, and organometallic compounds such as dibutyltin dilaurate. Examples of the stabilizer include a stabilizer against ultraviolet rays such as substituted benzotriazoles and a stabilizer against thermal oxidation such as a phenol derivative.

In addition, the insulating layer 30 may be made of an electrorheological fluid. An electrorheological fluid is a fluid whose viscoelastic properties change reversibly when an electric field is applied or removed. Particles in a uniform electrorheological fluid consisting of a single substance such as liquid crystal, or an insulating liquid. Examples thereof include a dispersion-based electrorheological fluid in which the above is dispersed. In particular, in the case of a dispersed electrorheological fluid, the solid-liquid phase can be changed depending on the presence or absence of an electric field, which is more preferable. Examples of the particles used in the dispersion-based electrorheological fluid include porous fine particles made of carbonaceous material and an insulating material. The average particle size of the fine particles is preferably 5 to 30 μm. Examples of the insulating liquid used for the dispersion-based electrorheological fluid include silicone oil. Further, the electrorheological fluid may be gelled by adding a cross-linking agent, a platinum catalyst, or the like to the insulating liquid and performing heat treatment.

In a gelled sheet of electrorheological fluid, when an electric field is applied, particles are buried in the gel and the surface state changes. That is, the gel is raised by the electric force at the interface, and the surface becomes a smooth flush surface of only the gel, and the gel comes into contact with the other layers on the entire surface to develop adsorption. In such a state, shear stress is easily transmitted to the insulating layer 30, and the detection sensitivity is improved. The method for producing a dispersed electroviscous fluid exists in the vicinity of the porous particles by adding the dried porous particles to the electrically insulating liquid with stirring while maintaining the temperature above the decomposition temperature of the electrically insulating liquid. Examples thereof include a method in which an electrically insulating liquid is decomposed to produce a low molecular weight organic compound, and the organic compound is uniformly adsorbed on the surface of the porous particles.

Conductive particles 80 such as carbon black, gold, silver, and nickel may be added to the insulating layer 30 at a ratio within a range in which the insulating property can be maintained (see FIG. 4). When the insulating layer 30 is pressed, the distance between the contained conductive particles becomes close and the capacitance value between the first electrode 20 and the second electrode 40 rises sharply, so that the shearing force described later is caused by this. This is because the calculation method of 60 has the effect of improving the sensitivity of pressure and shearing force. The average particle size of the conductive particles 80 is preferably 1/10 or less of the thickness of the insulating layer 30.

The material of the second electrode 40 is not particularly limited, but for example, a metal film such as gold, silver, copper, platinum, palladium, aluminum, rhodium, a conductive paste film in which these metal particles are dispersed in a resin binder, or Examples thereof include organic semiconductors such as polyhexylthiophene, polydioctylfluorene, pentacene, and tetrabenzoporphyrin, but the present invention is not particularly limited. In the case of a metal film, a method of manufacturing the plurality of second electrodes 40 includes a method of forming a conductive film on the entire surface by a plating method, a sputtering method, a vacuum vapor deposition method, an ion plating method, or the like, and then patterning by etching. In this case, a method of directly forming a pattern by a printing method such as a screen, gravure, or offset can be mentioned.

The second electrode 40 is mainly formed on the upper portion of the insulating layer 30, and may be formed of only one layer or a plurality of layers of two or more layers. The pattern of the second electrode 40 may be any shape such as a round shape, a square shape, and a linear shape. The thickness of the second electrode 40 may be appropriately selected within the range of 0.1 μm to 100 μm. A wiring pattern is connected from each of the second electrodes 40, and is electrically connected to an external controller. Then, by detecting the change in the capacitance value generated between the first electrode 20 and the plurality of second electrodes 40, the shearing force 60 applied from above the protective layer 50 can be calculated.

The material of the first electrode 20 is a metal film such as gold, silver, copper, platinum, palladium, aluminum, rhodium, a conductive paste film in which these metal particles are dispersed in a resin binder, or polyhexylthiophene or poly. Examples thereof include organic semiconductors such as dioctylfluorene, pentacene, and tetrabenzoporphyrin, but the present invention is not particularly limited. The forming method can be the same as that for the second electrode 40, but it is formed on the substrate 10 located below the insulating layer 30. Examples of the substrate 10 include a glass epoxy substrate, a polyimide substrate, and a polybutylene terephthalate resin substrate, but the substrate 10 is not particularly limited. The thickness may be appropriately selected between 0.1 mm and 3 mm.

The protective layer 50 is a layer for protecting the first electrode 20 and the plurality of second electrodes 40 at the lower part from the shearing force 60 applied from the upper part. Examples of the material of the protective layer 50 include a thermoplastic or thermosetting resin sheet such as acrylic, urethane, fluorine, polyester, polycarbonate, polyacetal, polyamide, and olefin, and an ultraviolet curable resin sheet such as cyanoacrylate. , Not particularly limited.

However, since the protective layer 50 also plays a role of accurately transmitting the shearing force 60 to the insulating layer 30, it is necessary to have the characteristics as a protective film as well as the characteristics as a pressure transmitter. Therefore, a polyester resin such as an acrylic resin, a urethane resin, a fluorine resin, or polyethylene terephthalate containing 10% or more of an acrylic rubber component is preferable. The thickness of the protective layer 50 varies depending on the material, but may be appropriately selected from 30 μm to 5 mm.

The shearing force 60 applied from above the protective layer 50 may be calculated by any method. For example, a change in the capacitance value generated between the first electrode 20 and the plurality of second electrodes 40. There is a method of calculating by detecting. That is, the protective layer 50 and the insulating layer 30 are deformed in a concave shape by the pressing force of the shearing force 60, whereby the plurality of second electrodes 40 formed on the insulating layer and the first one formed on the substrate 10. The distance to the electrode 20 changes. The change in the distance correlates with the pressing force of the shearing force 60 and the change in the capacitance value between the plurality of second electrodes 40 and the first electrode 20. Therefore, the pressing force of the shearing force 60 can be indirectly measured by measuring the change in the capacitance value between the plurality of second electrodes 40 and the first electrode 20.

Then, when the shearing force 60 is applied from an oblique direction (that is, when there is a component of the shearing force as well as the pressure direction), for example, the electrode 41 at one point of the plurality of second electrodes 40 is directly below the electrode 41. Not only the first electrode 21 at one point, but also the distance between the first electrode 22 adjacent to the first electrode 21 changes (see FIGS. 2 and 3). That is, if the change in the capacitance value between the electrode 41 and the first electrode 21 and the change in the capacitance value between the electrode 41 and the first electrode 22 are measured, the shearing force 60 in the oblique direction is measured. Can measure the strength of.

This point is an advantage of the present invention not found in Patent Document 1 (Japanese Unexamined Patent Publication No. 2018-72041) listed as a prior art. In fact, the pressure in the ground contact state such as a tire or a shoe sole is applied from directly above the protective layer 50. It can be said that the present invention is based on the ground contact state in the actual product because there is always a component of the force applied in the XY-axis direction applied from the oblique direction as well as the pressure applied only in the Z-axis direction.

It should be noted that the displacement of the electrode 41 at one point in the XY direction affects the other electrodes on the periphery, and is protected so that it does not become noise and affect the sensitivity of the capacitance value to be measured. A cut may be made on the surface of the layer 50. That is, each of the second electrodes 40 moves independently, and the displacement of one electrode 41 reduces the influence on the other surrounding second electrodes 40. When making this cut, the thickness of the insulating layer 30 is preferably slightly thicker in the range of 500 μm to 5 mm. The cut may be formed through the protective layer 50 to the surface of the insulating layer 30.

Examples of the form of the cut include a dotted line, a broken line, a long chain line, a single point chain line, and a long two point chain line. The cut may be a single line or a plurality of lines. The depth of the cut may be completely penetrated or may be half-cut halfway. Examples of the method for forming the cut include a method for punching a Thomson blade.

Hereinafter, as Example 1 of the present invention, a pressure sensor sheet when used in a tire ground contact state measuring device will be described. The pressure sensor sheet of Example 1 was manufactured by the following procedure. Liquid silicone rubber, vulverization cross-linking agent, triethylamine catalyst, phenol derivative stabilizer and methane-encapsulated microcapsule foaming agent in a weight ratio of 10: 4: 0.3: 0.1: 0.2 and a weight ratio of 10: 4 Each of the insulating layer raw materials mixed and stirred at a ratio of: 0.3: 0.1: 0.4 and a weight ratio of 10: 4: 0.3: 0.1: 0.6 was made of 125 μm thick polyester. Sorting was carried out by sequentially passing between calendar rolls having gaps of 0.2 mm, 0.15 mm and 0.1 mm thick on the carrier sheet. Next, when the liquid silicone rubber was crosslinked and the microcapsules were foamed by passing through a heating furnace at 120 ° C., the average size of the bubbles was 50 μm, and the density of the bubbles gradually increased. A width of 40 cm and a length of 2 m) were formed in three layers.

On this insulating layer, electrodes having a square pattern of 1 mm at intervals of 1.5 mm were formed, and a plurality of electrodes made of silver paste were formed on the entire surface of the insulating layer by a screen printing method. Next, a protective layer having a thickness of 0.5 mm made of a polycarbonate resin was laminated on the upper surface of the insulating layer via a urethane adhesive, and a first electrode having a thickness of 35 μm was formed on the lower surface of the insulating layer. A pressure sensor sheet was obtained by laminating a thick glass epoxy resin substrate. The plurality of electrodes and the first electrode were connected to a controller capable of detecting a change in capacitance value through a lead-out wiring.

Using the pressure sensor sheet manufactured above, the running speed of a radial tire consisting of a tire width of 195 mm, a flatness of 65%, and a wheel size of 15 inches under each environmental temperature of -40 ° C, 10 ° C, and 60 ° C is 40 km / hour. The pressure was tested in. The measurement results are as follows, and the pressure in the Y-axis direction as well as the X-axis direction could be measured. Further, in a low temperature environment, the shear pressure in the XY axis direction tended to increase, confirming the significance of measuring the shear pressure. We also confirmed the significance of the pressure sensor sheet formed of the insulating layer of silicone foam that can measure at such a wide environmental temperature.

Hereinafter, as Example 2 of the present invention, a pressure sensor sheet when used in a ground contact state measuring device for shoe soles will be described. The pressure sensor sheet of Example 2 was manufactured by the following procedure. In a constant temperature bath at 80 ° C., a dispersion-based electrorheological fluid made of silicone oil is mixed with dry porous fine particles made of an insulator having an average particle size of 20 μm, a sulfide cross-linking agent, and a platinum catalyst in a weight ratio of 10: 1: 1: 0. By adding, blending, and leaving at a ratio of 0.05 while stirring, the electrorheological fluid existing in the vicinity of the porous particles is decomposed to produce a low molecular weight organic compound, and the organic compound is the surface of the porous particles. An insulating layer (width 40 cm, length 2 m) made of a gel-like electrorheological fluid uniformly adsorbed on the particles was formed. The insulating layer was pressed with a jig processed into a counterbore-like convex shape to form a counterbore-like concave portion. The formed counterbore-shaped recesses have a shape in which the size of the holes is gradually reduced, and as a result, the insulating layer has a gradation in which the density of the material of the insulating layer changes stepwise from large to small.

On this insulating layer, electrodes having a square pattern of 1 mm at intervals of 1.5 mm were formed, and a plurality of electrodes made of copper were formed on the entire surface of the insulating layer by a partial plating method. Next, a protective layer having a thickness of 0.05 mm made of an acrylic resin was laminated on the upper surface of the insulating layer via a silicone adhesive, and a first electrode having a thickness of 35 μm was formed on the lower surface of the insulating layer. A pressure sensor sheet was obtained by laminating a 1 mm thick polyimide resin film substrate. The plurality of electrodes and the first electrode were connected to a controller capable of detecting a change in capacitance value through a lead-out wiring.

Using the pressure sensor sheet manufactured above, a tester wearing shoes with a size of 27 cm and a pressure sensor sheet attached was given a walking speed of 2 km / hour, 4 km / hour, and 6 km / hour at an ambient temperature of 20 ° C. They were asked to walk and the pressure at each walking speed was tested. The measurement results are as follows, and the force in the Y-axis direction as well as the X-axis direction could be measured. In addition, the higher the walking speed, the more the pressure applied to the sole, especially the shear force in the XY axis direction, tended to increase, confirming the significance of measuring the shear force.

Hereinafter, as Example 3 of the present invention, a pressure sensor sheet when used for a track pad of a personal computer will be described. The pressure sensor sheet of Example 3 was manufactured by the following procedure. Three kinds of foaming agents and carbon black having an average particle size of 30 μm were dispersed and stirred in a polystyrene resin solution dissolved in toluene at a weight ratio of 10: 0.6: 0.1, and the foaming agents were separated in the polystyrene resin solution. At the starting timing, a sheet-like foamed insulating layer was formed by passing heat through the gaps of the extrusion molding machine having a gap having a thickness of 0.5 mm. The three types of foaming agents are an azodicarbonamide-based foaming agent having a specific gravity of 1.65, an oxybisbenzenesulfonyl hydrazide-based foaming agent having a specific gravity of 1.49, and a dinitrosopentamethylenetetramine-based foaming agent having a specific gravity of 1.41. , The content is a weight ratio of 0.2 with respect to the polystyrene resin solution 10, respectively. Although the obtained sheet-shaped foam insulating layer was a single layer, it was an insulating layer having gradations different in the size and shape of bubbles.

On this insulating layer, electrodes having a square pattern of 1 mm at intervals of 1.5 mm were formed, and a plurality of electrodes made of copper were formed on the entire surface of the insulating layer by a partial plating method. Next, a protective layer having a thickness of 0.05 mm made of an acrylic resin is laminated on the upper surface of the insulating layer via a urethane adhesive, and a first electrode made of an organic semiconductor having a thickness of 10 μm is formed on the lower surface of the insulating layer. The formed 0.1 mm thick polyimide resin film substrate was laminated to obtain a pressure sensor sheet. The plurality of electrodes and the first electrode were connected to a controller capable of detecting a change in capacitance value through a lead-out wiring.

Using the pressure sensor sheet manufactured above, trace the track pad with the pressure sensor sheet attached with a size radius of 2 mm to the tester at speeds of 2 mm / sec, 10 mm / sec, and 40 mm / sec at an ambient temperature of 20 ° C. And tested the pressure at each speed. The measurement results are as follows, and the force in the Y-axis direction as well as the X-axis direction could be measured. In addition, the higher the tracing speed, the more the pressure applied to the track pad, especially the shearing force in the XY-axis direction, tended to increase, confirming the significance of measuring the shearing force.

1 Pressure sensor sheet 10 Substrate 20, 21, 22 First electrode 30 Insulation layer 32 Bubble 40, 41 Electrode 50 Protective layer 60 Shear force 70 Counterbore-shaped recess 80 Conductive particles

Claims (4)

The first electrode is formed on the substrate,
An insulating layer is formed on the first electrode,
A second electrode is formed on the insulating layer,
A pressure sensor sheet having a protective layer formed on the second electrode.
Material density, hardness, specific gravity, melting point, boiling point, specific heat, magnetic permeability, magnetization rate, refractive index, elastic coefficient, shear strength, tensile fracture nominal strain, tensile strength, impact resistance in a specific direction in the insulating layer. A pressure sensor sheet having gradations in which any one of property, abrasion resistance, compressibility, compressive strength, bending strength, and yield stress changes, and no other electrode layer is formed in the insulating layer. The pressure sensor sheet according to claim 1, wherein the insulating layer in the first half has a multi-layer structure. The pressure sensor sheet according to claim 1 or 2, wherein the gradation is a change in either hardness or elastic modulus among the listed materials. The pressure sensor sheet according to claim 3, wherein the gradation is a change in hardness among the listed materials.

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