JP7094845B2 - Pressure sensor sheet - Google Patents

Description

The present invention relates to a pressure sensor sheet capable of calculating a shear force for use in a device for measuring a ground contact state such as a tire, a sole, or a track point.

Conventionally, the invention disclosed in Patent Document 1 below is known as a method for measuring a ground contact state of a tire or the like. 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 of 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, when the sheet is pressed at the intersection of the first linear electrode and the second linear electrode in a plan view, the electrical resistance between the first linear electrode and the second linear electrode becomes smaller. 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 direction cannot be detected for the Y-axis component. That is, in the pressure sensor sheet having such a structure, only the contact pressure distribution in the Z-axis direction can be obtained. The distribution cannot be measured. Therefore, there is a problem that the true contact patch 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) in the XY axis direction applied diagonally from above the protective layer, and is based on the present invention. It is an invention in which the insulating layer formed between the first electrode and the second electrode is made of an elastic body having predetermined characteristics, and measures the true ground contact state of a tire, a shoe sole, a track point, or the like. Can be used as a device for.

That is, in the first embodiment of the present invention, the first electrode is formed on the substrate, the insulating layer having a Poisson ratio of 0 to 0.48 is formed on the first electrode, and the second electrode is formed on the insulating layer. Is a pressure sensor sheet in which a protective layer is formed on the second electrode, and is a pressure sensor sheet capable of calculating the shearing force applied from the protective layer.

Further, the second embodiment of the present invention is a pressure sensor sheet in which the insulating layer is made of any one of silicone foam, silicone gel, and silicone elastomer. Further, the third embodiment of the present invention is a pressure sensor sheet in which the insulating layer is made of an electrorheological fluid. Further, a fourth embodiment of the present invention is a pressure sensor sheet in which the insulating layer is made of a foam. Further, the fifth embodiment of the present invention is a pressure sensor sheet in which conductive particles are contained in the insulating layer. The sixth embodiment of the present invention is the pressure sensor sheet according to any one of the above, which is used in a device for measuring a ground contact state of any one of a tire, a shoe sole, and a track point.

In the pressure sensor sheet of the present invention, a first electrode is formed on a substrate, an insulating layer having a Poisson's ratio of 0 to 0.48 is formed on the first electrode, and a second electrode is formed on the insulating layer. It is a pressure sensor sheet in which a protective layer is formed on the second electrode, and is characterized in that the shearing force applied from the protective layer can be calculated.

Therefore, not only the conventional ground pressure distribution in the Z-axis direction but also the ground pressure distribution of stress (shear force) applied in the diagonal direction can be measured, so that true ground contact between the tire or shoe sole and the ground contact surface can be measured. The condition can be measured, and the true performance of tires and soles can be measured. Further, since an insulating layer having a Poisson's ratio of 0 to 0.48 is formed between the first electrode and the second electrode, it is possible to reduce noise around the pressing point generated by bending when pressed. .. As a result, it becomes easy to distinguish between the pressure detection in the Z-axis inspection direction and the shear force detection in the XY-axis direction, which has the effect of improving the accuracy of the detection data.

Further, the pressure sensor sheet of the present invention is characterized in that the insulating layer is made of an electrorheological fluid. Further, the insulating layer is characterized in that it is made of a foam. Therefore, when the applied pressure or shear force is released, the displacement generated by the release immediately returns to the origin, which has the effect of increasing the ability to measure the pressure or shear force. In addition, even if it is largely displaced, it returns to its original shape, so the sheet itself is not easily broken and has a high durability effect. Therefore, it can be applied to sensor devices according to each application, and has the effect that it can be used for devices for measuring all ground contact conditions, from heavy loads such as tires to small loads such as truck pads. be.

Further, the pressure sensor sheet of the present invention is characterized in that the insulating layer is made of any one of silicone foam, silicone gel, and silicone elastomer. Therefore, the elastic change due to the temperature is very small, the usable temperature range is wide, and there is an effect that the measurement can be performed even at a low temperature such as -50 ° C to 0 ° C.

Further, the pressure sensor sheet of the present invention is a pressure sensor sheet in which conductive particles are contained in the insulating layer. Therefore, the capacitance value changes significantly depending on the change in the distance between the conductive particles, which has the effect of improving the sensitivity.

It is sectional drawing of the pressure sensor sheet of one Embodiment of this invention. It is sectional drawing which shows one Embodiment when the pressing force is applied only from the upper direction to the pressure sensor sheet of this invention, and is deformed. It is sectional drawing which shows one Embodiment when the pressing force (shearing force) is applied from an oblique direction to the pressure sensor sheet of this invention, and it is deformed. It is sectional drawing of the pressure sensor sheet of one Embodiment of this invention which put conductive particles in the insulating layer and made the unevenness of the counterbore shape. It is sectional drawing of the pressure sensor sheet of one Embodiment of this invention which made a cut in the protective layer.

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. A pressure sensor sheet in which a protective layer 50 is formed on the second electrode 40 and the shearing force 60 applied from the protective layer 50 can be calculated (see FIG. 1). The first electrode 20 and the second electrode 40 may be interchanged. That is, the second electrode 40 may be formed on the substrate 10, and the first electrode 20 may be formed on the insulating layer 30.

The insulating layer 30 is preferably configured with a Poisson's ratio in the range of 0 to 0.48. The Poisson ratio referred to in the present invention is applied to JIS K 7127 and JIS K 7161 by cutting the insulating layer 30 into the shape of a dumbbell No. 1 test piece and using a non-contact stretch meter capable of measuring minute displacements. Longitudinal strain (amount of change in the axial direction / original length in the axial direction) and lateral strain (amount of change in the width direction / original length in the width direction) are measured by a compliant tensile test method, and the lateral strain is measured. It refers to the value obtained by dividing the value by the value of the longitudinal strain.

If the insulating layer 30 is very thin, or if the insulating layer 30 is integrated with the substrate 10 or the second electrode 40 and cannot be completely separated, the tensile test of the insulating layer 30 alone cannot be performed. The values measured in the same manner as above are obtained 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. It is the value of the Poisson's ratio of the present invention.

When the Poisson's ratio is less than 0, when the insulating layer 30 is pressed through the protective layer 50, the portion not pressed is also dented, so that a serious detection error is likely to occur. On the other hand, when the Poisson's ratio exceeds 0.48, the unpressed portion rises, and a serious detection error is likely to occur.
As a method for lowering the Poisson's ratio, the insulating layer 30 is formed by forming a counterbore-like unevenness 70 on the surface of the insulating layer 30 and swelling the protective layer 50 when the concave portion of the insulating layer 30 is pressed. There is a method to prevent it from swelling (see FIG. 4). The shape of the counterbore-shaped unevenness 70 may be appropriately selected depending on the material and thickness of the insulating layer 30.

Examples of the material of the insulating layer 30 include a synthetic resin sheet having elastic force such as silicone, fluorine, urethane, epoxy, ethylene vinyl acetate copolymer, polyethylene, polypropylene, polystyrene, and butadiene rubber, and an elastic non-woven fabric sheet. Be done. In particular, a silicone resin-based elastic sheet such as a silicone gel or a silicon elastomer is more preferable because it has excellent durability in a wide temperature range from low temperature to high temperature and also has excellent elastic force.

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.

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 the property resulting from the density (the density of the network structure in which the chain polymers are chemically bonded 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 in which silicone is blended 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 of manufacturing 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 as 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 sheet.

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 blending silicone oil with other elastomers such as urethanes and reacting. 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 then 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 formed 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 added to 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 organic metal compounds such as dibutyltin dilaurate. Examples of the stabilizer include stabilizers against ultraviolet rays such as substituted benzotriazoles and stabilizers against thermal oxidation such as phenol derivatives.

Further, the insulating layer 30 may be made of a foam. Examples of the foam include those obtained by finely dispersing gas in the synthetic resin of the insulating layer 30 and forming the foam into a foamy or porous shape. In particular, polyethylene, polypropylene, polystyrene, etc. have weak elastic force only by the sheet itself, and elastic force is generated by making it into a foam. Therefore, when these synthetic resins are selected as the material of the insulating layer 30. , It is preferable to keep it in a foam state.

As a method for producing a foam, a thermally decomposable foaming agent such as azodicarbonamide or hydrogen carbonate, or a heat-expandable microcapsule foaming agent in which freon or a hydrocarbon is wrapped in a thermoplastic resin capsule is dispersed in the synthetic resin. Examples thereof include a method of producing by a molding method such as bead foaming, batch foaming, press foaming, normal pressure secondary foaming, injection foaming, extrusion foaming, and foaming blow to which heat is applied.

The foam size of the foam is preferably 2 μm to 100 μm. As a method for producing a foam to obtain such a foam size, 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. This is because 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 constant desired expansion ratio and a constant cell size. .. Further, it is possible to significantly widen the range of the foaming ratio, and it is possible to obtain a product having a desired foaming ratio.

Among the foams, a silicone foam whose material is made of a silicone-based resin is preferable. It has the advantage of being able to handle measurements at low temperatures with little change in elasticity due to temperature, and because of its high durability, it is possible to 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 with a large load such as a tire, or when measuring an object with a small load such as a shoe sole.

Silicone foam is a foam made by independently foaming or semi-independently foaming silicone rubber. As mentioned above, in addition to the type in which a foaming agent is added to the silicone rubber and heated and foamed, a self-foaming reaction consisting of a two-component liquid silicone. Types etc. are mentioned. As a method of manufacturing the insulating layer 30 from the self-foaming reaction type silicone foam, a liquid silicone rubber raw material is made into a sandwich shape with 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, the insulating layer 30 may be made of an electrorheological fluid. An electroviscous fluid is a fluid whose viscoelastic properties change reversibly when an electric field is applied or removed. Examples thereof include a dispersion-based electroviscous 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 dispersed 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 dispersed 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 a heat treatment.

In a sheet of gelled electrorheological fluid, particles are buried in the gel and the surface state changes by applying an electric field. That is, the gel rises due to 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 electrically viscous fluid exists in the vicinity of the porous particles by adding the dried porous particles to the electrically insulating liquid while stirring while maintaining the decomposition temperature of the electrically insulating liquid or higher. 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 electrostatic 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, in addition to a metal film such as gold, silver, copper, platinum, palladium, aluminum, and rhodium, a conductive paste film or poly in which these metal particles are dispersed in a resin binder. Examples thereof include organic semiconductors such as hexylthiophene, polydioctylfluorene, pentacene, and tetrabenzoporphyrin. Examples of the method for manufacturing the second electrode 40 include a method of forming the entire surface of the conductive film by a plating method, a sputtering method, a vacuum vapor deposition method, an ion plating method, etc. in the former case, and then patterning by etching in the latter case. , A method of directly forming a pattern by a printing method such as gravure or offset.

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 may be composed 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 plurality of electrodes 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, a polybutylene terephthalate resin substrate, and the like, but the substrate 10 is not particularly limited. The thickness may be appropriately selected from about 0.1 mm to 3 mm.

The protective layer 50 is a layer for protecting the first electrode 20 and the second electrode 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 fluororesin, and 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 shear 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. A method of calculating by detecting is mentioned. 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 shear force 60 and the change in the capacitance value between the plurality of second electrodes 40 and the first electrode 20. Therefore, by measuring the change in the capacitance value between the plurality of second electrodes 40 and the first electrode 20, the pressing force of the shearing force 60 can be indirectly measured.

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 second electrode 41 at one of the plurality of second electrodes 40 is directly below the second electrode 41. Not only the first electrode 21 at one point in the above, 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 second electrode 41 and the first electrode 21 and the change in the capacitance value between the second electrode 41 and the first electrode 22 are measured, the diagonal direction is obtained. The strength of the shear force 60 can be measured.

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, and in fact, the pressure in a grounded 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 diagonal direction as well as the pressure applied only in the Z-axis direction.

It should be noted that the displacement of the second electrode 41 at this point in the shearing force direction affects the other second electrodes on the periphery, which becomes noise and does not affect the sensitivity of the capacitance value to be measured. A cut 90 may be made on the surface of the protective layer 50 (see FIG. 5). The second electrodes 40 and 41 move independently due to the cut 90, and the displacement of the electrodes 41 has the effect of reducing the influence on the other surrounding second electrodes 40. When making this cut, the thickness of the insulating layer 30 is preferably slightly thick and is 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 90 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, vulcanization cross-linking agent, triethylamine catalyst, phenol derivative stabilizer and methane-encapsulating microcapsule foaming agent were mixed and stirred at a weight ratio of 10: 4: 0.3: 0.1: 0.4. The insulating layer raw material was dispensed on a 125 μm-thick polyester carrier sheet through a calendar roll having a 0.3 mm-thick gap. Next, the liquid silicone rubber was crosslinked into a sheet by passing it through a heating furnace at 120 ° C., and the microcapsules were foamed. As a result, an insulating layer (width 40 cm, length) made of silicone foam having an average foam size of 50 μm was formed. 2m) was formed.

This insulating layer is cut into the shape of a dumbbell No. 1 test piece, and longitudinal strain and lateral strain are measured by a tensile test method conforming to JIS K 7127 and JIS K 7161 using a non-contact stretch meter. However, when the Poisson's ratio was measured, it was 0.28. On this insulating layer, a plurality of second electrodes made of silver paste having a pitch of 1.5 mm and a pattern of 1 mm square 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 of 1 mm. A pressure sensor sheet was obtained by laminating thick glass epoxy resin substrates. The plurality of second electrodes and the first electrode were connected to a controller capable of detecting a change in the 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 at 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 not only the pressure in the Z-axis direction but also the shear force in the XY-axis direction could be measured. In addition, in a low temperature environment, the shear force in the XY axis direction tended to increase, confirming the significance of measuring the shear force. In addition, the significance of the pressure sensor sheet formed of the insulating layer of silicone foam that can be measured at such a wide environmental temperature was confirmed.

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 dispersed electroviscous fluid made of silicone oil is mixed with dry porous fine particles made of an insulating material having an average molecular weight of 20 μm, a sulfide cross-linking agent, and a platinum catalyst in a weight ratio of 10: 1: 1: 0. By adding and blending at a ratio of 0.05 and leaving it to stand while stirring, the electrically insulating liquid existing in the vicinity of the porous particles is decomposed to generate 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 electroviscous fluid uniformly adsorbed on the particles was formed.

This insulating layer is cut into the shape of a dumbbell No. 1 test piece, and longitudinal strain and lateral strain are measured by a tensile test method conforming to JIS K 7127 and JIS K 7161 using a non-contact stretch meter. However, when the Poisson's ratio was measured, it was 0.48. On this insulating layer, a plurality of second electrodes made of copper having a pitch of 1.5 mm and a pattern of 1 mm square 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 polyimide resin film substrate having a thickness of 1 mm. The plurality of second electrodes and the first electrode were connected to a controller capable of detecting a change in the 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 not only the pressure in the Z-axis direction but also the shear force in the XY-axis direction could be measured. In addition, the higher the walking speed, the more the XY axial shear force applied to the sole of the shoe 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. An extrusion molding machine in which an azodicarbonamide foaming agent and carbon black having an average diameter of 30 μm are dispersed in a polystyrene resin material at a weight ratio of 10: 0.6: 0.1 to provide a gap of 0.5 mm thickness. A sheet-like insulating layer was formed through the space. Next, heat was applied to foam the beads, and pressure was applied to form counterbore-like irregularities on the surface.

This insulating layer is cut into the shape of a dumbbell No. 1 test piece, and longitudinal strain and lateral strain are measured by a tensile test method conforming to JIS K 7127 and JIS K 7161 using a non-contact stretch meter. However, when the Poisson's ratio was measured, it was 0.001. On this insulating layer, a plurality of second electrodes made of copper having a pitch of 0.6 mm and a pattern of 0.3 mm square 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 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 the 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 a speed of 2 mm / sec, 10 mm / sec, 40 mm / sec under an ambient temperature of 20 ° C. And tested the pressure at each speed. The measurement results are as follows, and not only the pressure in the Z-axis direction but also the shear force in the XY-axis direction could be measured. In addition, the higher the tracing speed, the more the XY-axis shear force applied to the track pad tended to increase, confirming the significance of measuring the shear force.

1 Pressure sensor sheet 10 Substrate 20, 21, 22 First electrode 30 Insulation layer 40, 41 Second electrode 50 Protective layer 60 Shear force 70 Counterbore-like unevenness 80 Conductive particles 90 Cuts

Claims (5)

The first electrode is formed on the substrate,
An insulating layer having a Poisson's ratio of 0 to 0.48 is formed on the first electrode.
A second electrode is formed on the insulating layer, and a second electrode is formed.
A pressure sensor sheet having a protective layer formed on the second electrode.
The insulating layer is composed of an electrorheological fluid.
A pressure sensor sheet that can calculate the shear force applied from above the protective layer. The insulating layer is made of any of silicone foam, silicone gel, and silicone elastomer.
The pressure sensor sheet according to claim 1. The insulating layer is made of a foam.
The pressure sensor sheet according to claim 1 or 2 . Conductive particles are contained in the insulating layer.
The pressure sensor sheet according to any one of claims 1 to 3 . Used in devices for measuring the ground contact of tires, soles, or track points,
The pressure sensor sheet according to any one of claims 1 to 4 .

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