Pressure-sensitive sensor

Abstract

A pressure-sensitive sensor 1A comprises: a base material 11; a resistor 14 provided on the upper surface 111 of the base material 11; a wiring pattern 12 provided on the upper surface 111 and connected to the resistor 14; comb tooth patterns 15A to 15I provided on the upper surface 111 and each independently connected to the resistor 14; a wiring pattern 16 provided on the upper surface 111; a base material 21; a connection body 22 provided on the lower surface of the base material 21; a spacer 30 interposed between the base materials 11, 21; and a spacer 40 provided on the lower surface 112 of the base material 11. The upper surface 111 has a highest portion 114 that is higher than other portions of the upper surface 111 due to the spacer 40, and inclined surfaces 115 extending from the highest portion 114. The comb tooth patterns 15A to 15I include comb tooth patterns 15A to 15I overlapping the inclined surfaces 115 in plan view.

Description

pressure sensor

[0001] The present invention relates to a pressure-sensitive sensor whose resistance value changes in response to an applied load. For designated countries where incorporation by reference of literature is permitted, the content of Japanese Patent Application No. 2024-152722 filed in Japan on September 4, 2024 is incorporated herein by reference and made a part of the description of this specification.

[0002] A known pressure-sensitive sensor includes a plurality of concentrically arranged comb-tooth patterns, resistors to which the comb-tooth patterns are connected at equal intervals, a first wiring pattern connected to the resistors, a second wiring pattern having a tip located at the center of the concentric circles, a first substrate on which the comb-tooth patterns, the first wiring pattern, and the second wiring pattern are provided, connectors facing the concentric circles, a second substrate on which the connectors are provided, and a spacer having an opening and interposed between the first substrate and the second substrate (see, for example, Patent Document 1). In this pressure-sensitive sensor, as the load applied to the second substrate increases, the comb-tooth patterns successively contact the connectors from the inside to the outside, causing a stepwise change in the resistance value between the first wiring pattern and the second wiring pattern.

[0003] International Publication No. 2022 / 130754

[0004] When the pressure-sensitive sensor is attached to the support via an adhesive, air bubbles may remain between the first substrate and the support surface of the support, causing the upper surface of the first substrate to deform into a convex shape. This convexity may cause the connector to come into contact with multiple comb-tooth patterns simultaneously, causing a sudden change in resistance and deteriorating the output characteristics of the pressure-sensitive sensor.

[0005] The problem to be solved by the present invention is to provide a pressure-sensitive sensor capable of improving output characteristics.

[0006] [1] Aspect 1 of the present invention provides a first substrate having a first main surface and a second main surface, a resistor provided on the first main surface, a first wiring pattern provided on the first main surface and connected to the resistor, a plurality of comb-tooth patterns provided on the first main surface and each connected independently to the resistor, a pressing unit facing the comb-tooth pattern and approachable to the first main surface, and a pressing means including a connecting body held by the pressing unit and electrically connected to the comb-tooth pattern by pressing of the pressing unit, and a connecting body provided on the first main surface and electrically connected to the connecting body by pressing of the pressing unit, or a second wiring pattern included in a step and connected to the connector, and a first spacer provided on the second main surface, wherein the resistor is positioned in a position that does not overlap with the connector in a planar view, the first main surface has a highest portion that is higher than other portions of the first main surface by the first spacer, and an inclined surface extending from the highest portion, the plurality of comb tooth patterns include a plurality of first comb tooth patterns that overlap with the inclined surface in a planar view, and the pressure sensor has a resistance value between the first wiring pattern and the second wiring pattern that changes depending on the load applied to the pressing portion.

[0007] [2] Aspect 2 of the present invention may be a pressure-sensitive sensor in which, in the pressure-sensitive sensor of aspect 1, the first spacer overlaps with the connecting body in a planar view, and the opposing region of the first main surface facing the connecting body includes the highest part and the inclined surface.

[0008] [3] Aspect 3 of the present invention may be a pressure-sensitive sensor according to aspect 1 or 2, wherein the second wiring pattern is provided on the first main surface, and the highest portion overlaps with the second wiring pattern in a planar view.

[0009] [4] Aspect 4 of the present invention may be a pressure-sensitive sensor according to aspect 1 or 2, wherein the second wiring pattern is provided on the first main surface, the first wiring pattern is connected to a first end of the resistor, the plurality of comb-tooth patterns are connected between the first end and the second end of the resistor at intervals from each other, the plurality of comb-tooth patterns include a second comb-tooth pattern connected to the second end of the resistor, and the highest part is located closer to the second wiring pattern than the second comb-tooth pattern in a planar view.

[0010] [5] Aspect 5 of the present invention may be a pressure-sensitive sensor according to aspect 3 or 4, wherein the pressing means comprises a second substrate on which the connector is provided, and a second spacer interposed between the first substrate and the second substrate, and the second spacer has an opening that allows the connector to face the second wiring pattern and the comb tooth pattern.

[0011] [6] Aspect 6 of the present invention may be a pressure-sensitive sensor in which, in the pressure-sensitive sensor of aspect 1 or 2, the second wiring pattern is included in the pressing means and connected to the connector, the first wiring pattern is connected to a first end of the resistor, the multiple comb-tooth patterns are connected between the first end and second end of the resistor with a gap between them, the multiple comb-tooth patterns include a second comb-tooth pattern connected to the second end of the resistor, and the highest part overlaps with the second comb-tooth pattern in a planar view.

[0012] [7] Aspect 7 of the present invention may be a pressure-sensitive sensor in which, in the pressure-sensitive sensor of aspect 1 or 2, the second wiring pattern is included in the pressing means and connected to the connector, the first wiring pattern is connected to a first end of the resistor, the multiple comb-tooth patterns are connected between the first end and second end of the resistor with a gap between them, the multiple comb-tooth patterns include a second comb-tooth pattern connected to the second end of the resistor, and the highest part is located closer to the second comb-tooth pattern in a planar view than the other comb-tooth patterns.

[0013] [8] Aspect 8 of the present invention may be a pressure-sensitive sensor according to aspect 6 or 7, wherein the pressing means comprises a second substrate on which the connector and the second wiring pattern are provided, and a second spacer interposed between the first substrate and the second substrate, and the second spacer has an opening that allows the connector to face the comb tooth pattern.

[0014] [9] Aspect 9 of the present invention may be a pressure-sensitive sensor in any one of aspects 1 to 8, wherein the first wiring pattern is connected to a first end of the resistor, the plurality of comb-tooth patterns are connected between the first end and the second end of the resistor at intervals from each other, the plurality of comb-tooth patterns include a second comb-tooth pattern connected to the second end of the resistor, and in an opposing region of the first main surface opposing the connector, the width of the second comb-tooth pattern is wider than the width of the other comb-tooth patterns.

[0015]

[10] Aspect 10 of the present invention may be a pressure-sensitive sensor according to any one of aspects 1 to 9, wherein the plurality of comb tooth patterns are arranged parallel to each other at intervals in an opposing region of the first main surface that faces the connector.

[0016]

[11] Aspect 11 of the present invention may be a pressure-sensitive sensor according to aspect 10, wherein the first wiring pattern is connected to a first end of the resistor, the plurality of comb-tooth patterns are connected between the first end and the second end of the resistor at intervals from each other, and the plurality of comb-tooth patterns are provided on the first main surface such that the closer the connection position of the comb-tooth pattern with the resistor is to the second end, the closer the comb-tooth pattern is to the highest point.

[0017]

[12] Aspect 12 of the present invention may be a pressure-sensitive sensor according to aspect 10 or 11, wherein the plurality of comb tooth patterns are arranged concentrically around the highest point in a plan view.

[0018]

[13] Aspect 13 of the present invention may be a pressure-sensitive sensor according to any one of aspects 1 to 12, wherein the plurality of comb tooth patterns includes a third comb tooth pattern connected to a first end of the resistor, and the first wiring pattern is connected to the third comb tooth pattern.

[0019]

[14] Aspect 14 of the present invention is a pressure sensor according to any one of aspects 1 to 13, wherein the first spacer is a pressure sensor disposed between a support having a support surface that supports the pressure sensor and the second main surface.

[0020]

[15] A fifteenth aspect of the present invention may be the pressure-sensitive sensor of any one of Aspects 1 to 14, wherein the material constituting the resistor has an electrical resistivity higher than the electrical resistivity of the material constituting the first wiring pattern, the electrical resistivity of the material constituting the first comb-tooth pattern, the electrical resistivity of the material constituting the connector, and the electrical resistivity of the material constituting the second wiring pattern.

[0021] In the present invention, a first spacer is provided on the second main surface of the first base material, the first main surface of the first base material has a highest portion that is higher than other portions of the first main surface by the first spacer, and an inclined surface extending from the highest portion, and the plurality of first comb-tooth patterns overlap the inclined surface in a plan view, so that the plurality of first comb-tooth patterns can be brought into contact with the connecting body in sequence, thereby improving the output characteristics of the pressure-sensitive sensor.

[0022] FIG. 1 is a plan view showing a pressure-sensitive sensor according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1. FIG. 3 is a plan view showing a lower membrane substrate according to the first embodiment of the present invention. FIG. 4 is a bottom view showing a spacer and an upper membrane substrate according to an embodiment of the present invention. FIG. 5 is a cross-sectional view of a pressure-sensitive sensor showing a modified spacer according to an embodiment of the present invention. FIGS. 6(a) to 6(c) are cross-sectional views showing the operation of a pressure-sensitive sensor according to the first embodiment of the present invention. FIG. 6(a) is a diagram showing a state in which a connector begins to contact a comb-tooth pattern, FIG. 6(b) is a diagram showing a state in which the applied load is increased compared to FIG. 6(a), and FIG. 6(c) is a diagram showing a state in which the applied load is further increased compared to FIG. 6(b). FIG. 7(a) is a graph showing the output characteristics of a pressure-sensitive sensor according to the first embodiment of the present invention, FIG. 7(b) is a graph showing the output characteristics of a pressure-sensitive sensor according to Comparative Example 1, and FIG. 7(c) is a graph showing the output characteristics of a pressure-sensitive sensor according to Comparative Example 2. FIG. 8 is a plan view showing a pressure-sensitive sensor according to a second embodiment of the present invention. Fig. 9 is a cross-sectional view taken along line IX-IX in Fig. 8. Fig. 10 is a plan view showing a lower membrane substrate in a second embodiment of the present invention. Fig. 11 is a bottom view showing a spacer and an upper membrane substrate in the second embodiment of the present invention. Fig. 12 is a plan view showing a modified lower membrane substrate in the second embodiment of the present invention. Fig. 13 is a plan view showing a lower membrane substrate of a pressure-sensitive sensor in a third embodiment of the present invention. Fig. 14 is a plan view showing a modified lower membrane substrate of a pressure-sensitive sensor in the third embodiment of the present invention. Fig. 15 is a cross-sectional view showing a pressure-sensitive sensor in a fourth embodiment of the present invention. Fig. 16 is a plan view showing a lower membrane substrate of a pressure-sensitive sensor in a fifth embodiment of the present invention.

[0023] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0024] <<First embodiment>> Figure 1 is a plan view showing a pressure-sensitive sensor 1A in a first embodiment of the present invention, Figure 2 is a cross-sectional view taken along line II-II in Figure 1, Figure 3 is a plan view showing a lower membrane substrate 10 in this embodiment, and Figure 4 is a bottom view showing a spacer 30 and an upper membrane substrate 20 in this embodiment.

[0025] The pressure-sensitive sensor 1A in this embodiment is a sensor whose resistance value changes depending on the magnitude of the load applied. As shown in Figures 1 to 4, this pressure-sensitive sensor 1A includes a lower membrane substrate 10, an upper membrane substrate 20, and spacers 30 and 40. The upper membrane substrate 20 and the spacer 30 correspond to an example of a "pressure means" in this aspect of the present invention, the spacer 40 corresponds to an example of a "first spacer" in this aspect of the present invention, and the spacer 30 corresponds to an example of a "second spacer" in this aspect of the present invention.

[0026] 3, the lower membrane substrate 10 is a wiring board including a substrate 11, a wiring pattern 12, a resistor 14, comb-tooth patterns 15A to 15I, and a wiring pattern 16. The substrate 11 corresponds to an example of a "first substrate" in this aspect of the present invention, the wiring pattern 12 corresponds to an example of a "first wiring pattern" in this aspect of the present invention, the wiring pattern 16 corresponds to an example of a "second wiring pattern" in this aspect of the present invention, and the comb-tooth patterns 15A to 15I correspond to an example of a "comb-tooth pattern" in this aspect of the present invention.

[0027] The substrate 11 is a film-like member made of a flexible and electrically insulating material. Examples of materials that can be used for the substrate 11 include resin materials, and more specifically, polyethylene terephthalate (PET) and polyethylene naphthalate (PEN).

[0028] The wiring pattern 12 is formed by printing a conductive paste on the upper surface 111 of the substrate 11 and solidifying (curing) it. The conductive paste is composed of conductive particles and a binder resin mixed with water or a solvent and various additives. The conductive paste that constitutes the wiring pattern 12 is a low-resistance conductive paste having a relatively low electrical resistance value. Note that the method for forming the wiring pattern 12 is not particularly limited to the above. For example, instead of using a conductive paste, the wiring pattern 12 may be formed by etching a metal foil.

[0029] Specific examples of conductive particles include silver, copper, nickel, tin, bismuth, zinc, indium, and palladium, as well as alloys thereof. Specific examples of binder resins include acrylic resins, polyester resins, epoxy resins, vinyl resins, urethane resins, phenolic resins, polyimide resins, silicone resins, and fluororesins. Examples of solvents contained in the conductive paste include α-terpineol, butyl carbitol acetate, butyl carbitol, 1-decanol, butyl cellosolve, diethylene glycol monoethyl ether acetate, and tetradecane.

[0030] Although not particularly limited, in this embodiment, a silver paste containing silver as the main component of conductive particles or a copper paste containing copper as the main component of conductive particles is used as the low-resistance conductive paste. Metal salts may be used as the conductive particles contained in the conductive paste. Examples of metal salts include salts of the metals described above. The binder resin may be omitted from the conductive paste. Instead of the conductive paste, a conductive ink may be used.

[0031] The method for applying the conductive paste is not particularly limited, and either a contact application method or a non-contact application method may be used. Specific examples of contact application methods include screen printing, gravure printing, offset printing, gravure offset printing, and flexographic printing. Specific examples of non-contact application methods include inkjet printing, spray application, dispense application, and jet dispensing. The heat source for curing the conductive paste is not particularly limited, and examples include an electric heating oven, an infrared oven, a far-infrared oven (IR), a near-infrared oven (NIR), and a laser irradiation device, and a heat treatment using a combination of these may also be used.

[0032] In this embodiment, the wiring pattern 12 extends linearly along the X direction in the drawing. An end 121 of the wiring pattern 12 is covered by the resistor 14, and the wiring pattern 12 is connected to the resistor 14. Note that the planar shape of the wiring pattern 12 is not limited to the linear shape described above, as long as it is linear.

[0033] The resistor 14 is provided along the Y direction in the drawing, and one end 141 of the resistor 14 covers the end 121 of the wiring pattern 12. The resistor 14 is provided at a position on the base material 11 away from an opposing region 113 (described later) so as not to overlap with the connector 22 of the upper membrane substrate 20 in a plan view.

[0034] Like the wiring pattern 12 described above, the resistor 14 is formed by printing and curing a conductive paste on the upper surface 111 of the substrate 11. The conductive paste forming the resistor 14 is a high-resistivity conductive paste having a higher electrical resistance value than the low-resistivity conductive paste described above. The conductive paste forming the resistor 14 contains conductive particles having a higher electrical resistivity than the conductive particles in the conductive paste forming the wiring pattern 12 described above. That is, the resistor 14 is made of a material having a higher electrical resistivity than the material forming the wiring pattern 12, and the resistance value of the resistor 14 is sufficiently higher than the resistance value of the wiring pattern 12 to the extent that the resistance value of the wiring pattern 12 is negligible. Specifically, the resistance value of the resistor 14 is 10 times or more the resistance value of the wiring pattern 12, preferably 100 times or more the resistance value of the wiring pattern 12. Furthermore, the electrical resistivity of the material forming the resistor 14 is 10 times or more the electrical resistivity of the material forming the wiring pattern 12, preferably 100 times or more the electrical resistivity of the material forming the resistor 14.

[0035] A specific example of such a high-resistance conductive paste is carbon paste. Specific examples of the conductive particles contained in the conductive paste constituting the resistor 14 include carbon-based materials such as graphite, carbon black (furnace black, acetylene black, and ketjen black), carbon nanotubes, and carbon nanofibers. Carbon ink may be used instead of the carbon paste.

[0036] The multiple (nine in this example) comb tooth patterns 15A-15I are formed by printing and curing a low-resistance conductive paste on the upper surface 111 of the substrate 11, similar to the wiring pattern 12 described above. That is, each of the comb tooth patterns 15A-15I is made of a material having a lower electrical resistivity than the material constituting the resistor 14, and the resistance value of the resistor 14 is sufficiently higher than the resistance value of each of the comb tooth patterns 15A-15I, to the extent that the resistance values ​​of the respective comb tooth patterns 15A-15I can be ignored. Specifically, the resistance value of the resistor 14 is 10 times or more, preferably 100 times or more, than the resistance value of the comb tooth patterns 15A-15I. Furthermore, the electrical resistivity of the material constituting the resistor 14 is 10 times or more, preferably 100 times or more, than the electrical resistivity of the material constituting the comb tooth patterns 15A-15I. The method for forming the comb tooth patterns 15A-15I is not particularly limited to the above. For example, instead of using a conductive paste, the comb-tooth patterns 15A to 15I may be formed by etching a metal foil.

[0037] Like the wiring pattern 12 described above, the wiring pattern 16 is formed by printing and curing a low-resistivity conductive paste on the upper surface 111 of the substrate 11. That is, the wiring pattern 16 is made of a material having a lower electrical resistivity than the material constituting the resistor 14, and the resistance value of the resistor 14 is sufficiently higher than the resistance value of the wiring pattern 16 to the extent that the resistance value of the wiring pattern 16 can be ignored. Specifically, the resistance value of the resistor 14 is 10 times or more, preferably 100 times or more, than the resistance value of the wiring pattern 16. Furthermore, the electrical resistivity of the material constituting the resistor 14 is 10 times or more, preferably 100 times or more, than the electrical resistivity of the material constituting the wiring pattern 16. Note that the method for forming the wiring pattern 16 is not limited to the above. For example, instead of using a conductive paste, the wiring pattern 16 may be formed by etching a metal foil.

[0038] In this embodiment, each of the comb tooth patterns 15A to 15I has a linear portion 151 and an arc portion 152. The linear portion 151 of each of the comb tooth patterns 15A to 15I extends linearly along the X direction in the figure, and a portion of the linear portion 151 is located outside the facing region 113. In contrast, the arc portion 152 of each of the comb tooth patterns 15A to 15I is located within the facing region 113 and is electrically connected to the resistor 14 via the linear portion 151. Here, the facing region 113 is a circular region on the upper surface 111 of the base material 11 that faces the connector 22 of the upper membrane substrate 20 in a plan view.

[0039] In this embodiment, the portion of the comb tooth patterns 15A to 15I located within the facing region 113 functions as a detection portion 155 that detects the load applied to the pressure-sensitive sensor 1A, and this detection portion 155 includes an arc portion 152. In contrast, the portion of the comb tooth patterns 15A to 15I located outside the facing region 113 functions as a lead portion 156 that electrically connects the detection portion 155 to the resistor 14, and this lead portion 156 includes a part of the straight portion 151.

[0040] The straight line portions 151 of the comb-tooth patterns 15A to 15I are connected between the ends 141 and 142 of the resistor 14 at intervals along the direction from one end 141 to the other end 142 of the resistor 14 (the Y direction in the figure). That is, the comb-tooth patterns 15A to 15I are individually and independently connected to the resistor 14. The comb-tooth patterns 15A to 15I are electrically insulated from one another on the substrate 11 by ensuring intervals between the comb-tooth patterns 15A to 15I, except for the electrical connection via the resistor 14. The number of comb-tooth patterns is not particularly limited to the above, as long as there are multiple comb-tooth patterns. The one end 141 of the resistor 14 corresponds to an example of a "first end" in this aspect of the present invention, and the other end 142 of the resistor 14 corresponds to an example of a "second end" in this aspect of the present invention.

[0041] The ends of the linear portions 151 of the comb tooth patterns 15A to 15I are covered with resistors 14, and the comb tooth patterns 15A to 15I are connected to the resistors 14. The resistors 14 are interposed between the ends of the linear portions 151 of the comb tooth patterns 15A to 15I. In the facing region 113, the linear portion 151 of the outermost comb tooth pattern 15A of the nine comb tooth patterns 15A to 15I is connected to one end 141 of the resistor 14. On the other hand, the linear portion 151 of the innermost comb tooth pattern 15I of the nine comb tooth patterns 15A to 15I in the facing region 113 is connected to the other end 142 of the resistor 14. The linear portion 151 of the outermost comb tooth pattern 15A is directly connected to an end 121 of the wiring pattern 12. A resistor 14 is also interposed between the end 121 of the wiring pattern 12 and the end of the linear portion 151 of the comb tooth pattern 15B. The outermost comb-tooth pattern 15A does not have to be directly connected to the wiring pattern 12.

[0042] In this embodiment, the comb-tooth patterns 15A to 15I are connected to the resistor 14 at substantially equal intervals, but this is not particularly limited as long as the comb-tooth patterns 15A to 15I are connected to the resistor 14 at intervals from one another. Although not particularly shown, for example, in the facing region, the more outer the position of the comb-tooth pattern, the narrower the connection interval between the comb-tooth pattern and the resistor may be.

[0043] The straight line portions 151 of the nine comb-tooth patterns 15A to 15I extend linearly from the resistor 14 toward the −X side in the figure to the facing region 113, and extend substantially parallel to one another with a gap therebetween. The wiring pattern 16 also extends substantially parallel to the straight line portion 151 of the comb-tooth pattern 15I with a gap therebetween, but this wiring pattern 16 extends to the center CP of the facing region 113 and has a tip end 161 at the center CP. Although not particularly shown, a portion of this wiring pattern 16 may be covered by the other end 142 of the resistor 14.

[0044] The tip portion 161 is an expanded diameter portion having a circular shape with a diameter larger than the width of other portions of the wiring pattern 16 (for example, the portions of the wiring pattern 16 other than the tip portion 161 in the facing region 113). In this way, by having the expanded diameter portion 161 at the tip of the wiring pattern 16, it is possible to stabilize load detection when pressing begins. Note that the planar shape of the expanded diameter portion 161 is not limited to a circle and may be, for example, an ellipse, an oval, a rectangle, a polygon, or the like. Also, the wiring pattern 16 does not have to have an expanded diameter portion at its tip.

[0045] In contrast, the comb-tooth patterns 15A to 15I extend substantially parallel to one another at intervals in the facing region 113 so as to surround the periphery of the tip portion 161 of the wiring pattern 16. More specifically, in this embodiment, the comb-tooth patterns 15A to 15I each have an arc portion 152 that extends in an arc shape so as to surround the periphery of the tip portion 161 of the wiring pattern 16 in the facing region 113. The arc portions 152 of the multiple comb-tooth patterns 15A to 15I are arranged concentrically with the tip portion 161 of the wiring pattern 16 as the center.

[0046] In this embodiment, the arc portions 152 of the comb tooth patterns 15A to 15I are arranged at substantially equal intervals, but the arrangement of the arc portions 152 is not particularly limited to this as long as an interval is ensured between the arc portions 152. For example, although not particularly shown, in the facing region, the intervals between the arc portions of the comb tooth pattern may be narrower as the comb tooth pattern is positioned further outward.

[0047] Furthermore, in this embodiment, a case has been described in which the pressing start position (contact start position of the connector 22 with the lower membrane substrate 10) (specific point) of the pressing tool (described later) coincides with the center CP of the facing region 113, but this pressing start position may be a position other than the center CP of the facing region 113 and can be set arbitrarily as long as it is within the facing region 113. In this case, the comb tooth pattern is arranged concentrically around the pressing start position other than the center CP of the facing region 113.

[0048] In this embodiment, the arc portions 152 of the comb tooth patterns 15A to 15H have the same width w０ On the other hand, the arc portion 152 of the innermost comb tooth pattern 15I has a width W ０ Wider width than １ (w １ >w ０ ) The arcuate portions 152 of all the comb tooth patterns 15A to 15I may have the same width.

[0049] The innermost comb-tooth pattern 15I may be connected to the wiring pattern 16 via a connecting wire, thereby allowing the output of the pressure-sensitive sensor 1A in the non-pressure state to be set to a desired value.

[0050] Furthermore, the shape of the comb-tooth pattern detection portion is not particularly limited to the above-mentioned shape, as long as multiple comb-tooth patterns are arranged at intervals from the inside to the outside in the facing region. Although not particularly shown, for example, comb-tooth patterns 15A to 15I may have a bent portion having a substantially U-shape that bends at a right angle in place of arc portion 152 in facing region 113.

[0051] In addition, in this embodiment, the comb tooth patterns 15A to 15I extend linearly outside the facing region 113, but the planar shape of the comb tooth patterns outside the facing region is not particularly limited to this as long as it is linear. In addition, in this embodiment, the comb tooth patterns 15A to 15I are arranged substantially parallel even outside the facing region 113, but this is not particularly limited, and the multiple comb tooth patterns do not have to be arranged substantially parallel outside the facing region.

[0052] 4, the upper membrane substrate 20 includes a base material 21 and a connector 22. The base material 21 corresponds to an example of a "second base material" in this aspect of the present invention, and the connector 22 corresponds to an example of a "connector" in this aspect of the present invention.

[0053] The substrate 21 is a film-like member made of a flexible and electrically insulating material, similar to the substrate 11 described above. Examples of materials that can be used for the substrate 21 include resin materials, and more specifically, polyethylene terephthalate (PET) and polyethylene naphthalate (PEN). A metal film may also be used as the substrate 21. In this case, the substrate 21 may also function as the connector 22, i.e., the substrate 21 may also serve as the connector 22.

[0054] 1 and 4, the connectors 22 have a circular planar shape corresponding to the arc portions 152 of the comb tooth patterns 15A to 15I of the lower membrane substrate 10. More specifically, the connectors 22 have a circular shape with a diameter larger than the diameter of the arc portion 152 of the outermost comb tooth pattern 15A. In the present embodiment, the connectors 22 have a diameter smaller than the diameter of the openings 31 of the spacer 30, but this is not particularly limited, and the connectors 22 may have a diameter equal to or larger than the inner diameter of the openings 31. The connectors 22 are formed on the base material 21 so as to face the arc portions 152 of the comb tooth patterns 15A to 15I when the membrane substrates 10 and 20 are stacked via the spacer 30, and so that the centers of the connectors 22 overlap the tip portions 161 of the wiring patterns 16.

[0055] Similar to the wiring pattern 12 described above, the connectors 22 are formed by printing and curing a low-resistance conductive paste on the lower surface 212 of the substrate 21. That is, the connectors 22 are made of a material having a lower electrical resistivity than the material constituting the resistor 14, and the resistance of the resistor 14 is sufficiently higher than the resistance of the connectors 22 to the extent that the resistance of the resistor 14 is negligible. Specifically, the resistance of the resistor 14 is 10 times or more, preferably 100 times or more, than the resistance of the connectors 22. Furthermore, the electrical resistivity of the material constituting the resistor 14 is 10 times or more, preferably 100 times or more, than the electrical resistivity of the material constituting the connectors 22. The method for forming the connectors 22 is not limited to the above. For example, instead of using a conductive paste, the connectors 22 may be formed by etching a metal foil.

[0056] The connector 22 may also include a protective layer that covers the above-described layer formed by printing and curing a conductive paste for the resistor. This protective layer is formed by printing and curing a high-resistance conductive paste that has a higher electrical resistance value than the above-described low-resistance conductive paste. Specific examples of such high-resistance conductive paste include, but are not limited to, carbon paste.

[0057] The spacer 30 is a film-like member made of a flexible and electrically insulating material, similar to the above-described base materials 11 and 21. Examples of materials that make up the spacer 30 include resin materials, and more specifically, examples of such materials include polyethylene terephthalate (PET) and polyethylene naphthalate (PEN).

[0058] The spacer 30 has a circular opening 31 corresponding to the arc portions 152 of the comb tooth patterns 15A to 15I of the lower membrane substrate 10. More specifically, the opening 31 has a circular shape with an inner diameter larger than the diameter of the arc portion 152 of the outermost comb tooth pattern 15A. Although not particularly limited, it is preferable that the distance between the opening 31 and the arc portion 152 of the outermost comb tooth pattern 15A in a plan view is equal to or greater than the thickness of the spacer 30. The opening 31 is formed at a position corresponding to the arc portions 152 of the comb tooth patterns 15A to 15I of the lower membrane substrate 10 and the connectors 22 of the upper membrane substrate 20. When the membrane substrates 10 and 20 are stacked via the spacer 30, the arc portions 152 of the comb tooth patterns 15A to 15I and the connectors 22 face each other via the opening 31, and the tip portions 161 of the wiring patterns 16 also face the connectors 22.

[0059] The planar shape of the opening 31 is not limited to a circle, and may be, for example, an ellipse, an oval, a rectangle, a polygon, etc. Furthermore, the shapes of the connectors 22 and the detection units 155 of the comb-tooth patterns 15A to 15I are not particularly limited to those described above, and may be, for example, a shape corresponding to the shape of the opening 31. The portion of the base material 21 of the upper membrane substrate 20 that faces the opening 31 corresponds to an example of a "pressure portion" in this aspect of the present invention.

[0060] The lower membrane substrate 10 and the upper membrane substrate 20 are stacked via a spacer 30. Specifically, the upper surface 111 of the base material 11 of the lower membrane substrate 10 and the lower surface of the spacer 30 are bonded to each other via an adhesive layer (not shown), and the upper surface of the spacer 30 and the lower surface 212 of the base material 21 of the upper membrane substrate 20 are bonded to each other via an adhesive layer (not shown).

[0061] 1, in a plan view, the center CP of the facing region 113 of the lower membrane substrate 10 coincides with the center of the opening 31 of the spacer 30. Furthermore, in a plan view, the center CP coincides with the center of the tip 161 of the wiring pattern 16 of the lower membrane substrate 10, and also coincides with the center of the connector 22 of the upper membrane substrate 20. The connector 22 of the upper membrane substrate 20 faces the tip 161 of the wiring pattern 16 of the lower membrane substrate 10 and the arc portions 152 of the comb-tooth patterns 15A to 15I via the opening 31 of the spacer 30.

[0062] 2, the spacer 30 ensures a gap between the connector 22 and the tip 161 of the wiring pattern 16, and also ensures a gap between the connector 22 and the comb-tooth patterns 15A to 15I. As will be described later, the load applied by the presser deforms the base material 21 of the upper membrane substrate 20, and this deformation brings the connector 22 and the tip 161 of the wiring pattern 16 into contact with each other and electrically connects them, and also brings the connector 22 and the comb-tooth patterns 15A to 15I into contact with each other and electrically connects them.

[0063] In this embodiment, the thickness of the spacer 30 is set so that the connector 22 does not come into contact with the comb-tooth patterns 15A to 15I or the wiring pattern 16 when not pressed, but is not limited to this. The thickness of the spacer 30 may also be set so that the connector 22 is always in contact with the comb-tooth patterns 15A to 15I or the wiring pattern 16.

[0064] Here, in this embodiment, "electrically connecting" a connector and a comb-tooth pattern means a state in which the resistance between the connector and the comb-tooth pattern is equal to or less than a predetermined threshold, and does not include the above-mentioned state in which the connector and the comb-tooth pattern are simply in contact when not pressed. Similarly, in this embodiment, "electrically connecting" a connector and a wiring pattern means a state in which the resistance between the connector and the wiring pattern is equal to or less than a predetermined threshold, and does not include the above-mentioned state in which the connector and the wiring pattern are simply in contact when not pressed.

[0065] 2, the spacer 40 is disposed between the lower surface 112 of the base material 11 of the lower membrane substrate 10 and the support surface 71 of the support 70 that supports the pressure-sensitive sensor 1A. A specific example of the support 70 is a housing that houses the pressure-sensitive sensor 1A, such as a controller housing.

[0066] The spacer 40 is a small film-like piece made of an electrically insulating material. Examples of materials that make up the spacer 40 include resin materials, and more specifically, polyethylene terephthalate (PET) and polyethylene naphthalate (PEN). The spacer 40 is attached to the lower surface 112 of the base material 11 of the lower membrane substrate 10 via an adhesive layer (not shown).

[0067] 1, the spacer 40 has a circular planar shape that is approximately the same size as the expanded diameter portion 161 of the wiring pattern 16. In a planar view, the spacer 40 is disposed so as to overlap with the connector 22 of the upper membrane substrate 20, and also overlaps with the facing region 113 on the upper surface 111 of the base material 11 of the lower membrane substrate 10. Although not particularly limited, in a planar view, the center of the spacer 40 coincides with the center CP of the facing region 113 of the lower membrane substrate 10.

[0068] 2, the facing region 113 of the substrate 11 has a highest point 114 that is higher than the other parts of the facing region 113 (parts of the facing region 113 excluding the highest point 114) due to the spacer 40. The facing region 113 also has an inclined surface 115 extending from the highest point 114.

[0069] Specifically, since the spacer 40 is disposed in the center of the facing region 113, the highest part 114 is also located in the center of the facing region 113. Although not particularly limited, the center of this highest part 114 also coincides with the center CP of the facing region 113 of the lower membrane substrate 10 in a plan view.

[0070] The inclined surfaces 115 extend radially from the entire circumference of the highest portion 114 toward the outer periphery of the facing region 113 in the radial direction of the facing region 113. The inclined surfaces 115 are inclined downward toward the −Z side in the figure as they move from the highest portion 114 toward the outer periphery of the facing region 113. The inclined surfaces 115 as a whole have a shape corresponding to the outer periphery (side surface) of a truncated cone.

[0071] The enlarged diameter portion 161 of the wiring pattern 16 of the lower membrane substrate 10 is disposed at the highest portion 114 of the facing region 113. On the other hand, the comb tooth patterns 15A to 15I of the lower membrane substrate 10 are disposed on the inclined surface 115 of the facing region 113. In this embodiment, the comb tooth pattern 15A corresponds to an example of the "first comb tooth pattern" and an example of the "third comb tooth pattern" in the aspects of the present invention, the comb tooth patterns 15B to 15H correspond to an example of the "first comb tooth pattern" and an example of the "second comb tooth pattern" in the aspects of the present invention, and the comb tooth pattern 15I corresponds to an example of the "first comb tooth pattern" and an example of the "second comb tooth pattern" in the aspects of the present invention.

[0072] The shape of the spacer 40 is not particularly limited to the above, as long as it forms the highest portion 114 in the facing region 113. For example, a spacer 41 having a truncated cone shape as shown in FIG. 5 may be used instead of the spacer 40. FIG. 5 is a cross-sectional view of a pressure-sensitive sensor 1A including a spacer 41, which is a modified example of the spacer 40 in this embodiment. When using this spacer 41, it is preferable that the spacer 41 and the lower surface 112 of the substrate 11 are bonded only at the top of the spacer 41, and that no adhesive be interposed between the inclined surface of the spacer 41 and the lower surface 112 of the substrate 11.

[0073] The operation of the pressure-sensitive sensor 1A described above will be described with reference to FIGS. 6(a) to 7(c).

[0074] Figures 6(a) to 6(c) are cross-sectional views showing the operation of pressure-sensitive sensor 1A in this embodiment, with Fig. 6(a) showing the state where connector 22 begins to contact comb tooth pattern 15I, Fig. 6(b) showing the state where the applied load is increased compared to Fig. 6(a), and Fig. 6(c) showing the state where the applied load is further increased compared to Fig. 6(b). Also, Fig. 7(a) is a graph showing the output characteristics of pressure-sensitive sensor 1A in this embodiment, Fig. 7(b) is a graph showing the output characteristics of the pressure-sensitive sensor in Comparative Example 1, and Fig. 7(c) is a graph showing the output characteristics of the pressure-sensitive sensor in Comparative Example 2.

[0075] Before a load is applied to the pressure-sensitive sensor 1A, the connector 22 is not in contact with any of the comb tooth patterns 15A to 15I or the wiring pattern 16. Therefore, as shown in Figure 7(a), the pressure-sensitive sensor 1A outputs an infinite resistance value as the resistance value between the wiring patterns 12 and 16. Although not specifically shown, for example, the wiring patterns 12 and 16 are connected to an external device equipped with a resistance measuring unit that measures the resistance value between the wiring patterns 12 and 16, and a predetermined voltage is applied to the wiring pattern 16 from this external device.

[0076] FIG. 7(a) is a graph showing the output characteristics (F (load) - R (resistance) characteristics) of the pressure-sensitive sensor 1A in this embodiment, with the horizontal axis representing the load applied to the pressure-sensitive sensor 1A and the vertical axis representing the resistance value between the wiring patterns 12 and 16, which changes depending on the applied load. The resistance value between the wiring patterns 12 and 16 changes depending on the connection positions of the comb-tooth patterns 15A to 15I, which are connected to the wiring pattern 16 via the connectors 22 at the resistor 14, and therefore the output of the pressure-sensitive sensor 1A is stepped, as shown in FIG. 7(a). Therefore, the resolution of the pressure-sensitive sensor 1A can be improved by increasing the number of comb-tooth patterns and narrowing the pitch of the comb-tooth patterns.

[0077] When the pressure-sensitive sensor 1A is pressed by a presser (not shown), the base material 21 of the upper membrane substrate 20 begins to recess from the center of the opening 31 in the spacer 30, as shown in FIG. 6A. As a result, the connector 22 provided on the lower surface 212 of the base material 21 first contacts the tip 161 of the wiring pattern 16 of the lower membrane substrate 10, and the connector 22 contacts only the innermost comb-tooth pattern 15I. Because the innermost comb-tooth pattern 15I is connected to the second end 142 of the resistor 14, which is the farthest from the first end 141, the pressure-sensitive sensor 1A outputs a high resistance value R1 as the resistance between the wiring patterns 12 and 16, as shown in FIG. 7A. The load F1 corresponding to this resistance value R1 is the so-called "on load" that initiates electrical connection between the wiring patterns 12 and 16.

[0078] Although not specifically shown, the presser is a member made of, for example, a resin material, and is supported above the upper membrane substrate 20 so as to be able to approach and move away from the upper surface 211 of the base material 21 of the upper membrane substrate 20. In this embodiment, the presser is disposed so that its center coincides with the center of the opening 31 of the spacer 30 (the center CP of the facing region 113 of the base material 11 of the lower membrane substrate 10). When the presser presses the upper membrane substrate 20, the connector 22 is configured to first contact the tip 161 of the wiring pattern 16 and the innermost comb-tooth pattern 15I. An example of such a presser is an operation key on a controller. The presser may also be an operator's finger.

[0079] As the pressing force (applied load) of the presser increases, the recessed portion of the base material 21 of the upper membrane substrate 20 expands, and the connection targets of the connectors 22 expand to the outer comb-tooth patterns 15H to 15A. This shortens the distance between one end 141 of the resistor 14 and the connection position of the connection target, resulting in a decrease in the resistance value between the wiring patterns 12 and 16.

[0080] In this manner, in this embodiment, by changing the outermost comb tooth pattern among the comb tooth patterns in contact with the connector 22, the connection position of the resistor 14 with the wiring pattern 16 via the connector 22 and the comb tooth patterns 15A to 15I changes, and therefore the distance between one end 141 of the resistor 14 and the connection position changes. That is, in the pressure-sensitive sensor 1A of this embodiment, the resistance length (resistance value) of the resistor 14 changes depending on the pressing force applied by the presser.

[0081] As an example, as shown in Figure 6(b), when the applied load increases from the state in Figure 6(a) and the connector 22 comes into contact with the comb tooth pattern 15H in addition to the wiring pattern 16 and the comb tooth pattern 15I, the pressure-sensitive sensor 1A outputs a resistance value R2, which is smaller than the above-mentioned resistance value R1, as the resistance value between the wiring patterns 12 and 16, as shown in Figure 7(a).

[0082] Here, in the pressure-sensitive sensor of Comparative Example 1, which does not include the spacer 40, as described above, the resistance value may suddenly change due to air bubbles remaining between the substrate and the support. For example, as shown in Figure 7(b), if the design is such that the resistance value decreases by an amount of change ΔR each time one comb-tooth pattern comes into contact with the connector, when a load F' is applied, the connector may come into contact with three comb-tooth patterns simultaneously due to air bubbles, and the amount of change in resistance (ΔR x 3) may become three times the default value (ΔR).

[0083] In contrast, in this embodiment, as described above, the comb tooth patterns 15A to 15I are arranged on the inclined surface 115 of the facing region 113. Therefore, when the connector 22 contacts the outer comb tooth patterns 15H to 15A, the connector 22 contacts the comb tooth patterns 15H to 15A one by one in sequence. This allows the resistance value output by the pressure-sensitive sensor 1A to change in a stepped manner with an equal amount of change, as shown in Figure 7(a), improving the linearity of the output of the pressure-sensitive sensor 1A.

[0084] In addition, the pressers may have individual differences such as dimensional variations. In the pressure-sensitive sensor of Comparative Example 2, in which all comb tooth patterns have the same width, these individual differences in the pressers may affect the resistance value in the low load range. For example, in the example shown in Figure 7(c), the resistance value immediately after the start of pressing differs depending on the presser (first to third presser), and the resistance value in the low load range is not stable.

[0085] In contrast, in this embodiment, in the facing region 113, the width w １ is the width W of the other comb tooth patterns 15A to 15H ０ It's wider than (lol １ >w ０ 7A, the resistance value is significantly stable from the start of pressing until the connector 22 comes into contact with the comb-tooth pattern 15H, improving the linearity of the output of the pressure-sensitive sensor 1A.

[0086] When the applied load is further increased from the state shown in Fig. 6(b) and the pressure-sensitive sensor 1A is pressed in sufficiently, the connector 22 comes into contact with the wiring pattern 16 and all of the comb-tooth patterns 15A to 15I, as shown in Fig. 6(c). At this time, since the outermost comb-tooth pattern 15A is directly connected to the wiring pattern 12, the resistance between the wiring patterns 12 and 16 becomes substantially zero.

[0087] When the pressure of the presser is released, the opposite operation to the above occurs. That is, as the applied load decreases, the recessed portion of the base material 21 of the upper membrane substrate 20 becomes smaller, and the connection target of the connector 22 narrows to the inner comb-tooth patterns 15A to 15I. This increases the distance between one end 141 of the resistor 14 and the connection position of the connection target, resulting in an increase in the resistance value between the wiring patterns 12 and 16.

[0088] As described above, in this embodiment, the spacer 40 is provided on the lower surface 112 of the substrate 11, the upper surface 111 of the substrate 11 has a highest portion 114 that is higher than other portions of the upper surface 111 due to the spacer 40, and an inclined surface 115 extending from the highest portion 114, and the plurality of comb-tooth patterns 15A to 15H overlap the inclined surface 115 in a plan view. Therefore, the plurality of comb-tooth patterns 15A to 15I can be brought into contact with the connector 22 in order, and the output characteristics of the pressure-sensitive sensor 1A can be improved.

[0089] <<Second embodiment>> Figure 8 is a plan view showing a pressure-sensitive sensor 1B in a second embodiment of the present invention, Figure 9 is a cross-sectional view along line IX-IX in Figure 8, Figure 10 is a plan view showing the lower membrane substrate 10 in this embodiment, and Figure 11 is a bottom view showing the spacer 30 and upper membrane substrate 20 in this embodiment.

[0090] 8 to 11, the pressure-sensitive sensor 1B of the present embodiment differs from the pressure-sensitive sensor 1A of the first embodiment in that (1) the wiring pattern 16 is provided on the upper substrate 21 and directly connected to the connector 22, and (2) the linear comb-tooth patterns 15A to 15I do not have arc portions 152 but extend linearly over the facing region 113, but the rest of the configuration is the same as that of the first embodiment. Below, only the differences between the pressure-sensitive sensor 1B of the second embodiment and the first embodiment will be described, and the same components as those of the first embodiment will be assigned the same reference numerals and will not be described again.

[0091] 9 and 11 , the wiring pattern 16 in this embodiment is formed on the lower surface 212 of the base material 21 of the upper membrane substrate 20. This wiring pattern 16 is formed integrally with the connectors 22, and is thereby directly connected to the connectors 22. When a metal film is used as the base material 21, this base material 21 may have the function of the connectors 22, or the base material 21 may have the function of the wiring pattern 16.

[0092] 8 and 10, the plurality of comb tooth patterns 15A to 15I do not have arc portions 152, but are composed only of straight line portions 151, which extend linearly in the X direction in the facing region 113. In this embodiment, the straight line portions 151 of the plurality of comb tooth patterns 15A to 15I are arranged in the lower half of the facing region 113 (the -Y side in the drawings), and are arranged substantially parallel to one another at intervals from the center CP of the facing region 113 outward.

[0093] In this embodiment, too, the pressing start position of the pressing tool can be set to any position other than the center CP within the facing region 113. In this case, the straight line portions of the comb tooth pattern are arranged substantially parallel to each other at intervals from the pressing start position other than the center CP of the facing region 113 toward the outside of the facing region 113.

[0094] 9 and 10 , in this embodiment, a portion of the innermost comb tooth pattern 15I of the lower membrane substrate 10 is disposed at the highest portion 114 of the facing region 113. Meanwhile, the other comb tooth patterns 15A to 15H of the lower membrane substrate 10 are disposed on the inclined surface 115 of the facing region 113. In this embodiment, the comb tooth pattern 15A corresponds to an example of the "first comb tooth pattern" and an example of the "third comb tooth pattern" in this aspect of the present invention, the comb tooth patterns 15B to 15H correspond to an example of the "first comb tooth pattern" in this aspect of the present invention, and the comb tooth pattern 15I corresponds to an example of the "second comb tooth pattern" in this aspect of the present invention.

[0095] In the pressure-sensitive sensor 1B of this embodiment, as in the first embodiment, the connection position between the resistor 14 and the wiring pattern 16 via the connector 22 and the comb tooth patterns 15A to 15I changes depending on the magnitude of the pressing force (applied load) of the presser (not shown), and therefore the resistance value between the wiring patterns 12 and 16 changes.

[0096] As described above, in this embodiment, the spacer 40 is provided on the lower surface 112 of the substrate 11, the upper surface 111 of the substrate 11 has the highest portion 114 and the inclined surface 115, and the plurality of comb-tooth patterns 15A to 15H overlap the inclined surface 115 in a plan view. Therefore, the plurality of comb-tooth patterns 15A to 15H can be brought into contact with the connector 22 in order, thereby improving the output characteristics of the pressure-sensitive sensor 1B.

[0097] In addition, in this embodiment, in the opposing region 113, the width of the innermost comb tooth pattern 15I is wider than the width of the other comb tooth patterns 15A to 15H, so that the resistance value in the low load range is stable even if there are individual differences in the presser.

[0098] As shown in FIG. 12 , the innermost comb tooth pattern 15I of the lower membrane substrate 10 does not have to overlap with the highest portion 114 of the facing region 113 in a plan view. In this case, the highest portion 114 is located closer to the innermost comb tooth pattern 15I than the second innermost comb tooth pattern 15H in a plan view. FIG. 12 is a plan view showing a modified example of the lower membrane substrate 10 in the second embodiment of the present invention. In this modified example, the comb tooth pattern 15A corresponds to an example of the "first comb tooth pattern" and an example of the "third comb tooth pattern" in the aspects of the present invention, the comb tooth patterns 15B to 15H correspond to an example of the "first comb tooth pattern" and an example of the "second comb tooth pattern" in the aspects of the present invention, and the comb tooth pattern 15I corresponds to an example of the "first comb tooth pattern" and an example of the "second comb tooth pattern" in the aspects of the present invention.

[0099] <<Third Embodiment>> FIG. 13 is a plan view showing the lower membrane substrate 10 of a pressure-sensitive sensor according to a third embodiment of the present invention.

[0100] 13, the pressure-sensitive sensor of this embodiment differs from the pressure-sensitive sensor 1B of the second embodiment in that (1) the wiring pattern 16 is provided on the lower substrate 11, and (2) the wiring pattern 16 extends parallel to the innermost comb tooth pattern 15I in the facing region 113, but other configurations are the same as those of the second embodiment. Below, only the differences between the pressure-sensitive sensor of the third embodiment and the second embodiment will be described, and the same components as those of the second embodiment will be assigned the same reference numerals and will not be described again.

[0101] 13, the wiring pattern 16 in this embodiment is formed on the upper surface 111 of the base material 11 of the lower membrane substrate 10. In the facing region 113, this wiring pattern 16 extends linearly along the X direction in the figure, and extends parallel to the innermost comb-tooth pattern 15I.

[0102] In this embodiment, a portion of the wiring pattern 16 is disposed at the highest portion 114 of the facing region 113. On the other hand, the comb tooth patterns 15A to 15I of the lower membrane substrate 10 are disposed on the inclined surface 115 of the facing region 113. In this embodiment, the comb tooth pattern 15A corresponds to an example of the "first comb tooth pattern" and an example of the "third comb tooth pattern" in this aspect of the present invention, the comb tooth patterns 15B to 15H correspond to an example of the "first comb tooth pattern" in this aspect of the present invention, and the comb tooth pattern 15I corresponds to an example of the "first comb tooth pattern" and an example of the "second comb tooth pattern" in this aspect of the present invention.

[0103] In the pressure sensor of this embodiment, as in the second embodiment, the connection position between the resistor 14 and the wiring pattern 16 via the connector 22 and the comb tooth patterns 15A to 15I changes depending on the magnitude of the pressing force (applied load) of the presser (not shown), and therefore the resistance value between the wiring patterns 12 and 16 changes.

[0104] As described above, in this embodiment, the spacer 40 is provided on the lower surface 112 of the substrate 11, the upper surface 111 of the substrate 11 has the highest portion 114 and the inclined surface 115, and the plurality of comb-tooth patterns 15A to 15I overlap the inclined surface 115 in a plan view. Therefore, the plurality of comb-tooth patterns 15A to 15I can be brought into contact with the connector 22 in order, thereby improving the output characteristics of the pressure-sensitive sensor.

[0105] In addition, in this embodiment, in the opposing region 113, the width of the innermost comb tooth pattern 15I is wider than the width of the other comb tooth patterns 15A to 15H, so that the resistance value in the low load range is stable even if there are individual differences in the presser.

[0106] As shown in FIG. 14 , the wiring pattern 16 does not have to overlap the highest portion 114 of the facing region 113 in a plan view. In this case, the highest portion 114 is located closer to the wiring pattern 16 than the innermost comb tooth pattern 15I in a plan view. FIG. 14 is a plan view showing a modified example of the lower membrane substrate 10 in the third embodiment of the present invention. In this modified example, the comb tooth pattern 15A corresponds to an example of the "first comb tooth pattern" and an example of the "third comb tooth pattern" in the aspects of the present invention, the comb tooth patterns 15B to 15H correspond to an example of the "first comb tooth pattern" and an example of the "second comb tooth pattern" in the aspects of the present invention, and the comb tooth pattern 15I corresponds to an example of the "first comb tooth pattern" and an example of the "second comb tooth pattern" in the aspects of the present invention.

[0107] <<Fourth Embodiment>> FIG. 15 is a cross-sectional view showing a pressure-sensitive sensor 1D according to a fourth embodiment of the present invention.

[0108] 15, the pressure-sensitive sensor 1D of the fourth embodiment differs from the pressure-sensitive sensor 1A of the first embodiment in that (1) it has a pressing member 50 instead of the upper substrate 21, and (2) it has a support member 60 instead of the spacer 30, but the rest of the configuration is the same as that of the first embodiment. Below, only the differences between the pressure-sensitive sensor 1D of the fourth embodiment and the first embodiment will be described, and the same components as those of the first embodiment will be denoted by the same reference numerals and will not be described again.

[0109] The pressing member 50 is made of an electrically insulating elastic material such as silicone rubber. In this embodiment, a connecting body 22 is formed on the lower surface of the pressing member 50 instead of the base material 21. In this embodiment, the facing region 113 of the base material 11 of the lower membrane substrate 10 is the region on the upper surface 111 of the base material 11 that faces the connecting body 22.

[0110] In this embodiment, the pressing member 50 has a circular planar shape corresponding to the arc portions 152 of the comb tooth patterns 15A to 15I, but the planar shape of the pressing member 50 is not particularly limited to this. For example, the planar shape of the pressing member 50 may have a band-like planar shape corresponding to part of the arc portions 152 of the comb tooth patterns 15A to 15I. In this case, it is sufficient that the pressing member 50 partially overlaps with all of the comb tooth patterns 15A to 15I.

[0111] The support member 60 is also made of an elastic material such as silicone rubber, and is provided around the facing region 113 of the base material 11 of the lower membrane substrate 10. The pressing member 50 is supported by the support member 60 so that the connectors 22 face the detection units 155 of the comb-tooth patterns 15A to 15I and the tip ends 161 of the wiring patterns 16. In this embodiment, too, the center CP of the facing region 113 substantially coincides with the center of the tip ends 161 of the wiring patterns 16 in a plan view, and also substantially coincides with the center of the lower surface of the pressing member 50.

[0112] The connector 22, the pressing member 50 and the support member 60 correspond to an example of the "pressing means" in this aspect of the present invention, and the pressing member 50 corresponds to an example of the "pressing portion" in this aspect of the present invention.

[0113] In the pressure-sensitive sensor 1D of this embodiment, as in the first embodiment, the connection position between the resistor 14 and the wiring pattern 16 via the connector 22 and the comb tooth patterns 15A to 15I changes depending on the magnitude of the pressing force (applied load) of the pressing member 50, and therefore the resistance value between the wiring patterns 12 and 16 changes.

[0114] As described above, in this embodiment, the spacer 40 is provided on the lower surface 112 of the substrate 11, the upper surface 111 of the substrate 11 has the highest portion 114 and the inclined surface 115, and the plurality of comb-tooth patterns 15A to 15I overlap the inclined surface 115 in a plan view. Therefore, the plurality of comb-tooth patterns 15A to 15I can be brought into contact with the connector 22 in order, and the output characteristics of the pressure-sensitive sensor 1D can be improved.

[0115] It should be noted that the above-described embodiments have been described to facilitate understanding of the present invention, and are not intended to limit the present invention. Therefore, each element disclosed in the above-described embodiments is intended to include all design modifications and equivalents that fall within the technical scope of the present invention.

[0116] For example, in the first embodiment described above, the wiring pattern 16 is formed on the upper surface of the base material 11 of the lower membrane substrate 10, but this is not particularly limited. Specifically, in the embodiment shown in Figures 1 to 4, the wiring pattern 16 may be formed on the lower surface 212 of the base material 21 of the upper membrane substrate 20, and the wiring pattern 16 may be directly connected to the connector 22, as in the second embodiment.

[0117] In the fourth embodiment, the wiring pattern 16 is formed on the upper surface of the base material 11 of the lower membrane substrate 10, but this is not particularly limited. Specifically, in the embodiment shown in FIG. 15 , the wiring pattern 16 may be formed on the support member 60, and the wiring pattern 16 may be directly connected to the connector 22.

[0118] In the second to fourth embodiments, the spacer 40 may be replaced with a spacer 41 having a truncated cone shape as shown in FIG.

[0119] Furthermore, in the first embodiment described above, a predetermined voltage is applied to the wiring pattern 16 to obtain the resistance value between the wiring patterns 12 and 16, but the circuit configuration for obtaining the resistance value between the wiring patterns 12 and 16 is not particularly limited to this.

[0120] For example, as shown in Fig. 16, a wiring pattern 13 connected to the other end 142 of the resistor 14 may be provided on the base material 11. Fig. 16 is a plan view showing the lower membrane substrate 10 of the pressure-sensitive sensor according to the fifth embodiment of the present invention.

[0121] 16 , the wiring pattern 13 is covered with the other end 142 of the resistor 14, and the wiring patterns 12 and 13 are electrically connected via the resistor 14. An end 131 of the wiring pattern 13 is directly connected to the innermost comb-tooth pattern 15I. The wiring pattern 12 may be connected to a power supply and the wiring pattern 13 may be connected to ground, and a voltage corresponding to the resistance value between the wiring patterns 12 and 16 may be obtained from the wiring pattern 16.

[0122] DESCRIPTION OF SYMBOLS 1A, 1B, 1D...Pressure-sensitive sensor 10...Lower membrane substrate 11...Base material 111...Upper surface 112...Lower surface 113...Facing region 114...Highest part 115...Inclined surface 12...Wiring pattern 121...End part 13...Wiring pattern 131...End part 14...Resistor 141, 142...End part 15A to 15I...Comb-tooth pattern 151...Straight part 152...Circular part 155...Detection part 156...Lead part 16...Wiring pattern 161...Tip part 20...Upper membrane substrate 21...Base material 211...Upper surface 212...Lower surface 22...Connector 30...Spacer 31...Opening 40, 41...Spacer 50...Pressing member 60...Support member 70...Support body

Claims

1. A first substrate having a first main surface and a second main surface; a resistor provided on the first main surface; a first wiring pattern provided on the first main surface and connected to the resistor; a plurality of comb-tooth patterns provided on the first main surface and each connected independently to the resistor; a pressing unit facing the comb-tooth pattern and approaching the first main surface, and a connecting body held by the pressing unit and electrically connected to the comb-tooth pattern when pressed by the pressing unit; a second wiring pattern provided on the first main surface and electrically connected to the connecting body when pressed by the pressing unit, or included in the pressing unit and connected to the connecting body; and a first spacer provided on the second main surface, wherein the resistor is disposed at a position not overlapping with the connecting body in a plan view, and the first main surface has: a highest portion that is higher than other portions of the first main surface by the first spacer; and an inclined surface extending from the highest portion, The plurality of comb tooth patterns include a plurality of first comb tooth patterns that overlap with the inclined surface in a planar view, and a pressure-sensitive sensor in which the resistance value between the first wiring pattern and the second wiring pattern changes depending on the load applied to the pressing portion.

2. A pressure-sensitive sensor as described in claim 1, wherein the first spacer overlaps with the connecting body in a plan view, and the opposing region of the first main surface facing the connecting body includes the highest portion and the inclined surface.

3. A pressure-sensitive sensor according to claim 1 or 2, wherein the second wiring pattern is provided on the first main surface, and the highest part overlaps with the second wiring pattern in a plan view.

4. A pressure-sensitive sensor as claimed in claim 1 or 2, wherein the second wiring pattern is provided on the first main surface, the first wiring pattern is connected to a first end of the resistor, the plurality of comb-tooth patterns are connected between the first end and second end of the resistor with spaces between them, the plurality of comb-tooth patterns include a second comb-tooth pattern connected to the second end of the resistor, and the highest part is located closer to the second wiring pattern than the second comb-tooth pattern in a plan view.

5. A pressure-sensitive sensor as claimed in claim 3 or 4, wherein the pressing means comprises: a second substrate on which the connector is provided; and a second spacer interposed between the first substrate and the second substrate, and the second spacer has an opening that allows the connector to face the second wiring pattern and the comb-tooth pattern.

6. A pressure-sensitive sensor as claimed in claim 1 or 2, wherein the second wiring pattern is included in the pressing means and connected to the connector, the first wiring pattern is connected to a first end of the resistor, the plurality of comb-tooth patterns are connected between the first end and second end of the resistor with spaces between them, the plurality of comb-tooth patterns include a second comb-tooth pattern connected to the second end of the resistor, and the highest part overlaps with the second comb-tooth pattern in a plan view.

7. A pressure-sensitive sensor as claimed in claim 1 or 2, wherein the second wiring pattern is included in the pressing means and connected to the connector, the first wiring pattern is connected to a first end of the resistor, the plurality of comb-tooth patterns are connected between the first end and second end of the resistor with spaces between them, the plurality of comb-tooth patterns include a second comb-tooth pattern connected to the second end of the resistor, and the highest part is located closer to the second comb-tooth pattern than the other comb-tooth patterns in a plan view.

8. A pressure-sensitive sensor as claimed in claim 6 or 7, wherein the pressing means comprises: a second substrate on which the connector and the second wiring pattern are provided; and a second spacer interposed between the first substrate and the second substrate, the second spacer having an opening that allows the connector to face the comb-tooth pattern.

9. A pressure-sensitive sensor according to any one of claims 1 to 8, wherein the first wiring pattern is connected to a first end of the resistor, the plurality of comb-tooth patterns are connected between the first end and second end of the resistor with spaces between them, the plurality of comb-tooth patterns include a second comb-tooth pattern connected to the second end of the resistor, and in an opposing region of the first main surface opposing the connector, the width of the second comb-tooth pattern is wider than the widths of the other comb-tooth patterns.

10. A pressure-sensitive sensor according to any one of claims 1 to 9, wherein the plurality of comb-tooth patterns are arranged in parallel at intervals in an opposing region of the first main surface that faces the connector.

11. A pressure-sensitive sensor as described in claim 10, wherein the first wiring pattern is connected to a first end of the resistor, the plurality of comb-tooth patterns are connected between the first end and the second end of the resistor with a gap between them, and the plurality of comb-tooth patterns are provided on the first main surface such that the closer the connection position of the comb-tooth pattern with the resistor is to the second end, the closer the comb-tooth pattern is to the highest point.

12. A pressure-sensitive sensor according to claim 10 or 11, wherein the plurality of comb-tooth patterns are arranged concentrically around the highest part in a plan view.

13. A pressure-sensitive sensor according to any one of claims 1 to 12, wherein the plurality of comb-tooth patterns includes a third comb-tooth pattern connected to a first end of the resistor, and the first wiring pattern is connected to the third comb-tooth pattern.

14. A pressure sensor according to any one of claims 1 to 13, wherein the first spacer is disposed between a support having a support surface that supports the pressure sensor and the second main surface.

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