Capacitive Sensor

Abstract

Prevent the flexible structural parts from peeling off. [Solution] The capacitive sensor (10) comprises a substrate (12), a first electrode (14) provided on the substrate (12), a flexible member (15A) fixed to the substrate (12), and a second electrode (13) provided within the flexible member (15A) so as to face the first electrode (14) with a gap between them, for detecting capacitance between the first electrode (14) and the flexible member (15A). The flexible member (15A) has an electrode-embedded portion (11) that houses the second electrode (13) and has a gap between it and the surface (12a) of the substrate (12), a columnar portion (15) extending between the electrode-embedded portion (11) and the substrate (12), and an overlapping portion (15df) formed on the columnar portion (15) that passes through a through hole (17) that penetrates the substrate (12), and which overlaps the outer edge of the through hole (17) on the second surface (12b) opposite to the first surface (12a) of the substrate (12).

Description

Technical Field

[0001] The present invention relates to a capacitive sensor.

Background Art

[0002] In realizing a dexterous and powerful robot hand, a tactile sensor with high sensitivity, wide dynamic range, and high durability is important. For this reason, the present inventors have proposed capacitive tactile sensors having a flexible pillar structure that achieves high sensitivity and a wide dynamic range (Patent Documents 1 and 2).

[0003] This tactile sensor is of a capacitive type in which a capacitor is formed by a flexible electrode and a pad on a substrate. Here, the flexible structural portion is fixed to the substrate portion by applying an adhesive to the pillar and the surface of the substrate. In addition, in order to measure capacitance, it is necessary to connect the flexible electrode to a substrate such as a PCB. To achieve a space-saving overall sensor unit, a part of the flexible dielectric pillar is used as a flexible conductive pillar, and conductive adhesive is applied to a pad on the substrate to bond the conductive pillar, thereby enabling electrical connection between the flexible electrode and the substrate.

Prior Art Literature

Patent Literature

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of Invention

Problem to be Solved by the Invention

[0005] However, in the conventional technology described above, in which a flexible pillar structure is bonded and fixed to a substrate using adhesive, there is a possibility that the flexible pillar structure may peel off the substrate when a large external force (especially shear force) is applied to the fixed part. If the flexible pillar detaches from the substrate, the relative position of the pillar and the substrate shifts. This can cause a shift in the capacitance value of the capacitor formed by the electrode at the top of the pillar and the substrate pad, potentially resulting in drift offset and making it impossible to measure the capacitance value. Furthermore, the electrical connection between the substrate and the conductive pillar may be severed, potentially making it impossible to measure the capacitance value. As a result, there was a problem in that the sensor may not function properly.

[0006] Furthermore, if the amount of adhesive used is increased to ensure a strong bond—in other words, if the sides of the pillar are also fixed with adhesive in addition to the bottom surface of the pillar end—the flexibility of the pillar near the adhesive area may be insufficient, potentially leading to a decrease in sensor sensitivity. Therefore, there is room for improvement in the conventional technology.

[0007] This invention was made in view of the above circumstances. 1. Prevents the flexible structure from peeling off even when a strong shear force is applied to the sensor surface. 2. To enable connection maintenance with the lowest possible resistance without hindering the flexibility of the pillar near the bonding area. The objective is to provide a capacitive sensor that can perform the following functions. [Means for solving the problem]

[0008] <1> A capacitive sensor (10) according to one aspect of the present invention is Circuit board (12) and A first electrode (14) is provided on the first surface (12a) of the substrate (12), A flexible member (15A) having elasticity is fixed to the substrate (12), A second electrode (13) is provided within the flexible member (15A) so as to face the first electrode (14) while maintaining a distance between it and the first electrode (14), and is used to detect the capacitance between the second electrode (13) and the first electrode (14). Equipped with, The aforementioned flexible member (15A) is The electrode housing portion (11) incorporates the second electrode (13) and has a gap between it and the surface (12a) of the substrate (12), A columnar portion (15) extending between the electrode-integrated portion (11) and the substrate (12), The column portion (15) passing through the through hole (17) that penetrates the substrate (12) has an overlapping portion (15df) on the second surface (12b) of the substrate (12) opposite to the first surface (12a) that overlaps the outer edge of the through hole (17), It has This resolved the above issues. <2> The capacitive sensor of the present invention is as described above. <1> In, The flexible member (15A) is formed from a dielectric material. It is possible. <3> The capacitive sensor of the present invention is as described above. <1> In, The substrate (12) has conductive parts (14a, 14b), The column portion (15) has a conductor (15a) that connects the second electrode (13) and the conductive portions (14a, 14b). It is possible. <4> The capacitive sensor of the present invention is as described above. <1> In, The column portion (15) has a cover portion (15uf) on the first surface (12a) of the substrate (12) that covers the outer edge of the through hole (17). It is possible. <5> The capacitive sensor of the present invention is as described above. <3> In, The conductive portion (14b~14d) is provided on at least one portion of the inner circumferential surface of the through hole (17) of the substrate (12), the outer edge of the through hole (17) on the first surface (12a) of the substrate (12), and the outer edge of the through hole (17) on the second surface (12b) of the substrate (12), and is electrically connected to the conductive material (15a) of the column portion (15). It is possible. <6> The capacitive sensor of the present invention is as described above. <1> In, The overlapping portion (15df) is formed around the entire outer edge of the through hole (17), or on a portion of the outer edge of the through hole (17) in the circumferential direction. It is possible. <7> The capacitive sensor of the present invention is as described above. <1> In, Multiple columnar sections (15) are formed, The through holes (17) are formed in multiple locations. It is possible.

[0009] the above <1> According to the invention described above, a portion formed by a flexible member that deforms flexibly to detect an external load is fixed to a substrate portion that is somewhat rigid to the extent that it does not deform during detection, by through holes and overlapping portions. Therefore, unlike a state where the connection is made using only adhesive, even if a large external load is applied and the flexible member deforms, the overlapping portion will not come out of the through holes. This is because even if the flexible portion deforms as if being pulled, the overlapping portion maintains contact with the outer edge of the through hole, creating an anchor structure. Accordingly, the overlapping portion is a flexible member and is integrated with the pillar (column portion) configured to deform during detection, so when the flexible portion is pulled, it deforms simultaneously with the pillar without separating from the pillar. Therefore, the flexible portion does not separate from the substrate. Accordingly, the relative position of the counter electrodes forming a pair for the detection capacitance is maintained. Positional deviation between electrodes can be prevented, thereby preventing deviation of the capacitance value as a capacitor. In addition, disconnection of the conductive portion and the conductor, which serve as the wiring portion that conducts detection current, does not occur, detection operation can be maintained even when a large external load is applied, and the operational reliability of the sensor can be improved. At the same time, since the connection is not performed using an adhesive, the deformation of the flexible member is not inhibited, and the deformation of the pillar portion, which is a deformation member that transmits the magnitude of the applied external load as a change in the relative position of the second electrode serving as the detection portion, is not affected. Therefore, the detection sensitivity does not decrease, and accurate detection can be performed. In addition, the overlapping portion can increase the magnitude of the external load that is the limit for causing the flexible member locked to the substrate by the overlapping portion to separate from the substrate, and can expand the detection range of the sensor. Accordingly, a tactile sensor having high sensitivity, wide dynamic range, and high durability can be realized.

[0010] Here, the external load that deforms the flexible portion so as to be pulled includes not only the direction of peeling the flexible portion from the substrate portion, but also the direction of compressing the flexible portion toward the substrate portion, the direction along the substrate surface, or any combined oblique direction. This is because when a large external load close to or exceeding the limit is applied, the flexible portion may be separated from the substrate portion regardless of the application direction of the external load.

[0011] Note that the substrate is not limited to a flat plate such as a so-called PCB. For example, as long as the flexible member can be attached along the surface of an object having a certain volume such as a curved surface or the outer surface of a robot or the like, and electrodes and through holes can be formed at the corresponding locations, the present invention can be applied to any object for detecting an external load. In addition, the first electrode only needs to be arranged along the surface of the substrate, and the position in the thickness direction of the substrate is not limited. In this case, a conductive portion along the thickness direction of the substrate is provided.

[0012] Furthermore, a plurality of pillars (column portions) may be provided. In this case, it is only necessary to have a column portion that has an overlapping portion and is fixedly connected to the substrate, and it is also possible to have a pillar that is not provided with an overlapping portion. Furthermore, as the through hole, one provided in the substrate for forming a detection circuit may be used, or one provided in the substrate separately from the conductive portion for fixing the flexible member may be used. Furthermore, a portion where the overlapping portion contacts the second surface of the substrate can be bonded.

[0013] According to the invention described in <2> above, the electrode built-in portion that holds the second electrode and the wiring portion connected to the second electrode is formed of a flexible member, and the pillar portion that connects the wiring portion and the substrate is formed of a flexible member. The flexible member serves as a support member for the wiring portion, and also serves as a deformable member that converts the magnitude of an external load into the magnitude of deformation and transmits the deformation as a relative positional change to the second electrode that is a detection portion. Therefore, when the position of the electrode changes together with the flexible member during external load detection, there is no need to provide an insulating configuration other than the flexible member. At the same time, since the flexible member positioned between the second electrode and the first electrode is a dielectric, the dielectric constant between the two electrodes is increased to increase the capacitance between the electrodes, thereby improving sensor sensitivity. Similarly, when conductive materials that serve as wiring are formed in the pillars and overlapping sections, the flexible material and the conductive material will not break even if they deform, and the insulation state of the circuit can be maintained. Therefore, even when a large external load is applied, the detection operation can be maintained, improving the operational reliability of the sensor.

[0014] the above <3> According to the invention described above, since a conductor is formed on the column portion made of a flexible material, the conductor does not hinder the deformation of the column portion. Therefore, it is possible to transmit the current, which is the detection information from the second electrode, to the conductor portion without being affected by the deformation of the column portion, which is a deformable member that converts the magnitude of the external load into the magnitude of the deformation and transmits it to the second electrode, which is the detection portion, as a change in relative position. Therefore, the detection accuracy of the sensor is not reduced. In addition, since the deformation of the column portion does not become a disruption factor for the detection signal, it is possible to accurately detect the external load.

[0015] the above <4> According to the invention described above, the front and back surfaces of the outer edge surrounding the through hole can be sandwiched between the overlapping portion and the cover portion. This prevents misalignment between the flexible member and the substrate, and prevents the flexible portion from detaching from the substrate. Furthermore, since the overlapping portion and the cover portion are in contact with the front and back surfaces of the substrate, it is possible to reliably transmit sensor detection signals by forming a conductor and a conductive portion in that area.

[0016] the above <5> According to the invention described above, when an external load is applied, the flexible member deforms, causing the conductive material of the flexible member and the conductive part of the substrate to separate, which can affect electrical conductivity and potentially reduce the accuracy of sensor detection. However, this can be prevented. As a premise, in a flexible member, the second electrode and the conductor are formed by adding conductive powder to the material constituting the flexible member. Therefore, the electrical resistance of the conductor decreases when compressed. At the same time, the contact resistance of the pressed conductor with the conductive part decreases.

[0017] When an external load is applied, if the flexible member and the substrate separate near the through-hole, the portion opposite to the direction of the applied external load will be pressed against the separated portion. In other words, even if the contact area decreases and electrical resistance increases in the separated portion, the pressed portion is compressed, and its electrical resistance decreases. Therefore, the separation between the flexible member and the substrate due to the applied external load is offset, and the transmission of the detection current is not hindered. As a result, detection operation can be maintained even when a large external load is applied, increasing the detectable range of the sensor and improving the operational reliability of the sensor. Furthermore, if the flexible member is compressed in the direction of the applied external load, and the electrical resistance of the conductor at that location decreases, the overall electrical resistance will decrease if the portion in the opposite direction of the applied external load does not peel off.

[0018] the above <6> According to the invention described above, when the overlapping portion is formed around the entire outer edge of the through hole, the overlapping portion becomes less likely to come out of the through hole, preventing the flexible member from shifting position relative to the substrate or separating from the substrate. When the overlapping portion is formed on a part of the outer edge of the through hole in the circumferential direction, the area of ​​the overlapping portion in plan view becomes smaller, thus reducing the volume of the flexible member, making it lighter and saving space. Furthermore, when integrating the flexible member with the overlapping portion with the substrate, it is only necessary to pass the overlapping portion through the through hole and fix it in place, thus reducing the number of manufacturing steps. In this case, when the overlapping portion is formed on only a portion of the entire grain of the through-hole, it is preferable that the direction in which the overlapping portion extends in the circumferential direction relative to the through-hole is different for multiple columnar sections. This allows that even if an external load applied in one direction causes some of the overlapping portion to move out of the correct position relative to the through-hole, the columnar sections with overlapping portions formed in different directions will not move out of the through-hole, thereby improving the operational reliability of the sensor.

[0019] the above <7> According to the invention described above, in multiple columnar sections, overlapping sections and / or cover sections can be formed in different shapes. Here, different shapes include a state in which there are no overlapping sections and / or cover sections. Furthermore, in multiple columnar sections, those having a conductor and maintaining electrical contact with the substrate and those without a conductor and only connected to the substrate can be mixed together. Through-holes may be involved in electrical connections, such as vias or through-holes in a PCB, or they may simply serve to secure flexible components to the substrate. [Effects of the Invention]

[0020] According to the present invention, it is possible to realize a tactile sensor that has high sensitivity, a wide dynamic range, and high durability. [Brief explanation of the drawing]

[0021] [Figure 1] This is a schematic cross-sectional view showing a first embodiment of the capacitive sensor according to the present invention. [Figure 2] This is an enlarged cross-sectional view showing the main part of the first embodiment of the capacitive sensor according to the present invention. [Figure 3] This is a top view showing the substrate surface in a first embodiment of the capacitive sensor according to the present invention. [Figure 4] This is a cross-sectional view showing a conventional capacitive sensor with an external load applied. [Figure 5] This is a cross-sectional view showing a conventional capacitive sensor with an external load applied. [Figure 6] This is a cross-sectional view showing the state in which an external load is applied to the first embodiment of the capacitive sensor according to the present invention. [Figure 7] This is a cross-sectional view showing a modified example of the first embodiment of the capacitive sensor according to the present invention. [Figure 8] This is a cross-sectional view showing a modified example of the first embodiment of the capacitive sensor according to the present invention. [Figure 9]This is a cross-sectional view showing a modified example of the first embodiment of the capacitive sensor according to the present invention. [Figure 10] This is a cross-sectional view showing a modified example of the first embodiment of the capacitive sensor according to the present invention. [Figure 11] This is a cross-sectional view showing a modified example of the first embodiment of the capacitive sensor according to the present invention. [Figure 12] This is an enlarged cross-sectional view showing a second embodiment of the capacitive sensor according to the present invention. [Figure 13] This is an enlarged cross-sectional view showing a second embodiment of the capacitive sensor according to the present invention in a state where an external load is applied. [Figure 14] This is an enlarged cross-sectional view showing a second embodiment of the capacitive sensor according to the present invention in a state where an external load is applied. [Figure 15] This is an enlarged cross-sectional view showing a second embodiment of the capacitive sensor according to the present invention in a state where an external load is applied. [Figure 16] This is an enlarged cross-sectional view showing a second embodiment of the capacitive sensor according to the present invention in a state where an external load is applied. [Figure 17] This is an enlarged cross-sectional view showing a conventional capacitive sensor with an external load applied. [Figure 18] This is an enlarged cross-sectional view showing a second embodiment of the capacitive sensor according to the present invention in a state where an external load is applied. [Figure 19] This is an enlarged cross-sectional view showing a second embodiment of the capacitive sensor according to the present invention in a state where an external load is applied. [Figure 20] This is an enlarged cross-sectional view showing a second embodiment of the capacitive sensor according to the present invention in a state where an external load is applied. [Figure 21] This is an enlarged cross-sectional view showing a second embodiment of the capacitive sensor according to the present invention in a state where an external load is applied. [Figure 22] This graph illustrates the relationship between external force and resistance in the capacitive sensor according to the present invention. [Modes for carrying out the invention]

[0022] A first embodiment of the capacitive sensor according to the present invention will be described below with reference to the drawings. Figure 1 is a schematic cross-sectional view showing the capacitive sensor in this embodiment. Figure 2 is an enlarged cross-sectional view showing the capacitive sensor in this embodiment. Figure 3 is a top view showing the substrate surface of the capacitive sensor in this embodiment. In the figures, reference numeral 10 denotes the capacitive sensor.

[0023] As shown in Figures 1 to 3, the capacitive sensor 10 according to this embodiment includes an electrode housing section 11, a substrate 12, a flexible electrode (second electrode) 13, a flexible wiring (conductor) 13a, a substrate electrode (first electrode) 14, substrate surface wiring (substrate wiring, conductive part) 14a, 14b, a pillar (column section) 15, column wiring (flexible wiring, conductor) 15a, an overlapping section 15df, a through hole 17, and a control section 19.

[0024] The electrode-integrated portion 11 is arranged along the surface (first surface) 12a of the substrate 12. The electrode-integrated portion 11 is arranged facing the surface 12a of the substrate 12. The electrode-integrated portion 11 is arranged substantially parallel to the surface 12a of the substrate 12. The electrode-integrated portion 11 is spaced apart from the surface 12a of the substrate 12. The electrode-integrated portion 11 is formed from a flexible member 15A, which will be described later. The electrode-integrated portion 11 includes a plurality of flexible electrodes 13 and flexible wiring 13a.

[0025] The substrate 12 is flat. The substrate 12 can be a rigid substrate, such as a printed circuit board. The substrate 12 can be a flexible substrate. The substrate 12 is not limited to a plate shape as long as a flexible portion formed from the flexible member 15A can be fixed to the surface 12a and through holes 17 can be formed. The substrate 12 may be planar or curved. The substrate 12 may have a constant or non-constant thickness. The substrate 12 may be made of a material harder than the flexible member 15A, which will be described later. The substrate 12 is made of a material that can keep the deformation of the flexible portion formed from the flexible member 15A within a detectable range when detecting the external load F, which will be described later. Multiple substrate electrodes 14 and substrate surface wiring (substrate wiring) 14a, 14b are arranged along the surface 12a of the substrate 12. The substrate wiring 14a, 14b are each connected to the control unit 19. The substrate wiring 14a, 14b may be connected to the control unit 19 via connecting lines 19a.

[0026] The flexible electrode 13 is a transmitting electrode. Multiple flexible electrodes 13 are arranged on substantially the same plane. Multiple flexible electrodes 13 are on the same hierarchical level. The same hierarchical level means that they are arranged at approximately the same distance from the surface 12a of the substrate 12. Multiple flexible electrodes 13 are spaced apart from each other. Multiple flexible electrodes 13 all have approximately the same contour shape. Multiple flexible electrodes 13 all have the same area. When viewed from above, the spacing distance between adjacent flexible electrodes 13 is equal. The flexible electrode 13 is connected to the flexible wiring 13a. The flexible electrode 13 is electrically connected to the control unit 19 via the flexible wiring 13a, the column wiring 15a (described later), and the substrate surface wiring 14b. Each flexible electrode 13 faces the substrate electrode 14. Each flexible electrode 13 corresponds to a substrate electrode 14. In a plan view, each flexible electrode 13 is positioned to overlap the substrate electrode 14.

[0027] The substrate electrodes 14 are receiving electrodes. Multiple substrate electrodes 14 are arranged along the surface 12a of the substrate 12. Multiple substrate electrodes 14 are arranged on substantially the same plane. Multiple substrate electrodes 14 are on the same hierarchical level. Multiple substrate electrodes 14 are spaced apart from each other. Multiple substrate electrodes 14 all have substantially the same contour shape. Multiple substrate electrodes 14 all have substantially the same area. When viewed from above, the spacing distance between adjacent substrate electrodes 14 is equal. When viewed from above, the spacing distance between adjacent substrate electrodes 14 is equal to the spacing distance between adjacent flexible electrodes 13. The substrate electrodes 14 are connected to the substrate wiring 14b. The substrate electrodes 14 are electrically connected to the control unit 19 via the substrate wiring 14b.

[0028] The pillars 15 connect the electrode-embedded section 11 and the substrate 12 in the stacking direction. Both ends of the pillars 15 are connected to the electrode-embedded section 11 and the substrate 12. Multiple pillars 15 are formed on the surface 12a of the substrate 12. The multiple pillars 15 are spaced apart from each other. When viewed from above, all of the multiple pillars 15 have approximately the same cross-sectional contour shape. All of the multiple pillars 15 have approximately the same area. All of the multiple pillars 15 have approximately the same cross-sectional shape along their entire axial length in the direction away from the surface 12a of the substrate 12. When viewed from above, the spacing distance between adjacent pillars 15 is equal.

[0029] The cross-sectional contour shape of the pillar 15 in plan view can be the same as the contour shape of the flexible electrode 13. The cross-sectional contour shape of the pillar 15 in plan view may be larger than the contour shape of the flexible electrode 13. When viewed from above, the distance between adjacent pillars 15 may be equal to the distance between adjacent flexible electrodes 13. When viewed from above, the distance between adjacent pillars 15 may be greater than the distance between adjacent flexible electrodes 13. When viewed from above, the distance between adjacent pillars 15 may be less than the distance between adjacent flexible electrodes 13. Pillar 15 has column wiring 15a that conducts electrical connections between the electrode-embedded section 11 and the substrate 12 in the stacking direction. The column wiring 15a conducts electrical connections between the flexible wiring 13a and the substrate surface wiring 14b.

[0030] The electrode housing portion 11 and the pillar 15 are formed from a dielectric and flexible, elastically deformable elastomer. The electrode housing portion 11 and the pillar 15 are formed from a flexible member 15A made of the same material. The electrode housing portion 11 and the pillar 15 are formed integrally.

[0031] The flexible member 15A is formed from a flexible dielectric material such as silicone rubber, polyvinyl chloride (PVC) gel, polyvinylidene fluoride (PVDF), polydimethylsiloxane (PDMS), silicone resin, urethane resin, epoxy resin, styrene resin, or composite materials thereof. For example, the flexible member 15A can be made from a material with a dielectric constant of approximately ε = 1.4 F / m. The flexible member 15A can have material properties such as superelasticity, flexibility, stretchability, being a material containing fluids or bubbles, or being a material containing gases.

[0032] Furthermore, the flexible electrode 13, flexible wiring 13a, and column wiring 15a are all made of a conductor with elasticity. The flexible electrode 13, flexible wiring 13a, and column wiring 15a can be formed from a material that contains an additive that changes the conductivity or dielectric constant of the same flexible member 15A as the electrode housing part 11 and pillar 15. The wiring connected to the flexible electrode 13, flexible wiring 13a, and column wiring 15a can also be formed from the same material. The flexible electrode 13, flexible wiring 13a, and column wiring 15a may be formed, for example, by mixing conductive powder into the flexible member 15A. The flexible electrode 13, flexible wiring 13a, and column wiring 15a may be formed from a silicon-based resin mixed with conductors such as carbon, carbon nanofiber, or graphite, a silicon-based resin containing metal conductive fillers such as silver or copper, a thiophene-based conductive polymer, a conductive resin such as polystyrene sulfonic acid (PSS), or a composite material thereof.

[0033] The substrate electrodes 14 and substrate wiring 14a and 14b are formed from metal, conductive resin, or the like. The control unit 19 is connected to the flexible electrode 13 and the substrate electrode 14. The control unit 19 can detect the capacitance between the flexible electrode 13 and the substrate electrode 14.

[0034] The through-hole 17 is formed in the substrate 12. The through-hole 17 penetrates from the surface 12a to the back surface 2b of the substrate 12. The through-hole 17 is formed in a position that overlaps with the pillar 15 when viewed from above. The through-hole 17 may have the same diameter as the pillar 15. The through-hole 17 may have a smaller diameter than the pillar 15. The through-hole 17 may be formed in a position that does not overlap with the pillar 15 when viewed from above.

[0035] The pillar 15 has an end that connects to the substrate 12 and extends into the through hole 17. The pillar 15 extends to the back surface 12b of the substrate 12. An overlapping portion 15df is formed on the pillar 15 located on the back surface 12b of the substrate 12. The overlapping portion 15df is the part that overlaps with the substrate 12 when viewed from the direction normal to the substrate 12. The overlapping portion 15df contacts the outer edge of the through hole 17 on the back surface 12b of the substrate 12. The overlapping portion 15df is located along the outer edge of the through hole 17 along the back surface 12b of the substrate 12. The overlapping portion 15df is formed in a flange shape with an enlarged diameter relative to the pillar 15. The overlapping portion 15df is also formed in a flange shape with an enlarged diameter relative to the through hole 17. If the diameter of the through-hole 17 is smaller than the diameter of the pillar 15, the diameter of the overlapping portion 15df can be the same as that of the pillar 15.

[0036] The diameter of the overlapping portion 15df is larger than the diameter of the through hole 17. The diameter of the overlapping portion 15df is larger than the diameter of the pillar 15. The overlapping portion 15df has the same thickness in the circumferential direction. The overlapping portion 15df has the same thickness in the radial direction. The overlapping portion 15df is formed integrally with the pillar 15. The overlapping portion 15df is formed from a flexible member 15A which is the same material as the pillar 15. If a flexible column wiring 15a is formed on the pillar 15, the overlapping portion 15df may have a portion formed from the same material as the column wiring 15a.

[0037] The overlapping portion 15df can also be bonded to the back surface 12b of the substrate 12 by the adhesive portion 16. The overlapping portion 15df is bonded to the back surface 12b of the substrate 12 via the adhesive portion 16 in all pillars 15. The overlapping portion 15df does not have to be bonded to the back surface 12b of the substrate 12.

[0038] In this embodiment, when no external load F is applied to the capacitive sensor 10, the overlapping area between the flexible electrode 13 and the substrate electrode 14, viewed from above, is S. Furthermore, when no external load F is applied, the distance between the flexible electrode 13 and the substrate electrode 14 is d. When no external load F is applied, if the capacitance between the flexible electrode 13 and the substrate electrode 14 is C, the capacitance C is expressed by the following formula. C = ε·S / d

[0039] When an external load F is applied, the electrode housing 11 and the pillar 15 deform. The pillar 15 deforms in accordance with the direction of the external load F. When the external load F compresses the flexible electrode 13 and the substrate electrode 14, the distance d between the flexible electrode 13 and the substrate electrode 14 decreases. Alternatively, when the external load F separates the flexible electrode 13 and the substrate electrode 14, the distance d between the flexible electrode 13 and the substrate electrode 14 increases. In these cases, the capacitance C between the flexible electrode 13 and the substrate electrode 14 changes. By detecting this change in capacitance, it becomes possible to measure the external load F.

[0040] Alternatively, when an external load F is applied in a direction along the surface 12a of the substrate 12, the flexible electrode 13 shifts relative to the substrate electrode 14, and the area S over which the flexible electrode 13 overlaps the substrate electrode 14 changes to area S-Δ. As a result, the capacitance C between the flexible electrode 13 and the substrate electrode 14 changes. By detecting this change in capacitance, it becomes possible to measure the external load F.

[0041] Furthermore, the external load F can be in a direction not only normal to the surface 12a of the substrate 12 or along the surface 12a of the substrate 12, but also in a direction that is inclined at an angle. In this case, a change in the distance d between the electrodes and a change in the overlapping area S occur simultaneously. Consequently, the capacitance C between the flexible electrode 13 and the substrate electrode 14 changes. By detecting this change in capacitance, it becomes possible to measure the external load F.

[0042] Next, we will explain the state in which an external load is applied to a capacitive sensor.

[0043] Figure 4 is a schematic cross-sectional view illustrating a conventional capacitive sensor with an external load applied. In Figure 4, the external load F is shown being applied to the left along the surface 12a of the substrate 12. In the conventional structure, where the through-hole 17 and overlapping portion 15df are not provided and the end face of the pillar 15 is bonded to the surface 12a of the substrate 12 by the adhesive portion 16, when a large external load F is applied, as shown in Figure 4, the adhesive portion 16 peels off from the surface 12a of the substrate 12, and the flexible electrode 13 and the substrate electrode 14 cannot return to their positions before the external load F was applied. Therefore, even if the external load F is applied again, accurate detection becomes impossible.

[0044] Figure 5 is a schematic cross-sectional view illustrating a conventional capacitive sensor with an external load applied. In Figure 5, the external load F is shown being applied to the left along the surface 12a of the substrate 12. Similarly, in a conventional structure where the end face and even the side surface of the end face of the pillar 15 are bonded to the surface 12a of the substrate 12 by the adhesive portion 16, when an external load F is applied, as shown in Figure 5, the pillar 15 can only deform in the portion without the adhesive portion 16. As a result, the relative position change between the flexible electrode 13 and the substrate electrode 14 in response to the applied external load F becomes small, and the sensor sensitivity deteriorates.

[0045] Figure 6 is a schematic cross-sectional view illustrating the state in which an external load is applied to the capacitive sensor of this embodiment. In Figure 6, the external load F is shown to be applied in a leftward direction along the surface 12a of the substrate 12. In contrast to conventional structures, the capacitive sensor 10 of this embodiment, as shown in Figure 6, deforms relative to the substrate 12 when an external load F is applied, with the portion formed by the flexible member 15A being the external load.

[0046] When the applied external load F is greater than a predetermined value, the amount of deformation increases, and a shear force is applied to the connection portion between the flexible member 15A and the substrate 12, that is, near where the pillar 15 and the substrate 12 come into contact. At this time, an overlapping portion 15df is formed on the back surface 12b side of the pillar 15. Since the overlapping portion 15df is wider than the through hole 17, it forms an anchor structure, preventing the pillar 15 from coming out of the through hole 17.

[0047] Therefore, when the applied external load F is removed, the deformation of the flexible member 15A is released, and the positions of the flexible electrode 13 and the substrate electrode 14 return to their positions before the application of the external load F. As a result, the capacitance C returns to its original state. Therefore, even if the external load F is applied again, There is no discrepancy in the capacitance C value between the flexible electrode 13 and the substrate electrode 14, preventing drift and offset and enabling accurate detection.

[0048] In particular, when the overlapping portion 15df is bonded to the back surface 12b of the substrate 12 by the adhesive portion 16, a large external load F may cause the overlapping portion 15df on the opposite side of the direction in which the external load F is applied to peel off from the back surface 12b. Even in this case, since the overlapping portion 15df on the side in which the external load F is applied is bonded to the back surface 12b, the pillar 15 will not come out of the through hole 17. Therefore, when the applied external load F is removed, the deformation of the flexible member 15A is released, and the position of the flexible electrode 13 and the substrate electrode 14 returns to the position before the external load F was applied. As a result, the capacitance C returns to its original state. Therefore, even if the external load F is applied again, accurate detection can be performed.

[0049] In this case, as long as the overlapping portion 15df is not torn away from the pillar 15 by the shear force, it is possible to restore the positions of the flexible electrode 13 and the substrate electrode 14, and the capacitive sensor 10 of this embodiment can exhibit high durability. Therefore, it is possible to expand the sensor detection range in response to a large external load F.

[0050] To manufacture the capacitive sensor 10 of this embodiment, a substrate 12 is prepared in which through holes 17, substrate electrodes 14, and substrate wirings 14a and 14b are formed. Furthermore, an electrode housing portion 11, including flexible electrodes 13 and flexible wirings 13a, is formed using a flexible member 15A. In this case, a plate body formed from a flexible member 15A having recesses corresponding to the flexible electrodes 13 and flexible wirings 13a can be molded using a mold, and then the flexible electrodes 13 and flexible wirings 13a can be formed using a flexible member 15A with conductive particles mixed into the recesses of this plate body. Alternatively, the flexible electrodes 13 and flexible wirings 13a of a predetermined shape can be formed in predetermined positions first, and then the electrode housing portion 11 can be integrally formed to cover the flexible electrodes 13 and flexible wirings 13a.

[0051] Next, using a mold corresponding to the pillar 15, the pillar 15 and the column wiring 15a are formed so as to be integrated with the electrode-integrated section 11, which includes the flexible electrode 13 and the flexible wiring 13a. Similar to the flexible electrode 13 and the flexible wiring 13a, different processes and different molds can be used for the pillar 15 and the column wiring 15a. Next, the end of the pillar 15 is brought into contact with the substrate 12 and aligned with the corresponding through hole 17. Furthermore, the flexible member 15A forms the inside of the through hole 17 and the overlapping portion 15df so as to be continuous with the end of the pillar 15. At this time, the adhesive portion 16 can be formed prior to the formation of the overlapping portion 15df. This allows for the manufacture of a capacitive sensor 10.

[0052] The capacitive sensor 10 of this embodiment can be modified as follows.

[0053] Figure 7 is a schematic cross-sectional view showing a modified example of the capacitive sensor of this embodiment. In this modified example, as shown in Figure 7, the left pillar 15 has an overlapping portion 15df that is bonded to the back surface 12b of the substrate 12 via an adhesive portion 16. In contrast, the right pillar 15 has an overlapping portion 15df that is directly connected to the back surface 12b of the substrate 12, and no adhesive portion 16 is provided. Here, the adhesive portion 16 is formed on all contact surface areas of the overlapping portion 15df that contacts the back surface 12b of the substrate 12.

[0054] Furthermore, in this modified version, the contour shape of the flexible electrode 13 viewed from above is larger than the contour shape of the pillar 15. The contour shape of the flexible electrode 13 viewed from above is larger than the contour shape of the through hole 17. The contour shape of the flexible electrode 13 viewed from above has the same system dimensions as the contour shape of the overlapping portion 15df.

[0055] Figure 8 is a schematic cross-sectional view showing a modified example of the capacitive sensor of this embodiment. In this modified example, as shown in Figure 8, the substrate electrode 14 is formed at a position different from the through hole 17. In this example, in the pillar 15 fixed to the through hole 17 by the overlapping portion 15df, the substrate electrode 14 and substrate wiring 14a, 14b are not in contact with the through hole 17. At the same time, the overlapping portion 15df ensures that the substrate electrode 14 and substrate wiring 14a, 14b are not in contact with the through hole 17.

[0056] Figure 9 is a schematic cross-sectional view showing a modified example of the capacitive sensor of this embodiment. In this modified example, as shown in Figure 9, the ratio of the contour shape of the overlapping portion 15df to the contour shape of the pillar 15 is larger than in the configurations shown in Figures 2 and 6. In other words, the contour shape of the overlapping portion 15df relative to the through hole 17 is larger than in the configurations shown in Figures 2 and 6. Also, the thickness dimension of the overlapping portion 15df is larger than in the configurations shown in Figures 2 and 6. This modified example can be adapted when there is ample space on the back surface 12b side of the substrate 12, that is, when the thickness dimension of the sensor can be increased, or when the thickness dimension of the substrate 12 is large.

[0057] Figure 10 is a schematic cross-sectional view showing a modified example of the capacitive sensor of this embodiment. In this modified example, the right-side pillar 15 has the same configuration as the pillar 15 with the adhesive portion 16 shown in Figures 2 and 6, as shown in Figure 10. The left-side pillar 15 is entirely made up of column wiring 15a, connecting the flexible wiring 13a and the substrate wiring 14b across layers. Furthermore, a flexible member having the same conductivity as the flexible wiring 13a extends continuously from the end of the column wiring 15a through the left-side through-hole 17. In addition, the overlapping portion 15bdf is formed of a flexible member having the same conductivity as the flexible wiring 13a.

[0058] In other words, the flexible wiring 13a, the column wiring 15a, and the overlapping portion 15bdf are formed as a single unit. Furthermore, the overlapping portion 15bdf is connected to the back surface 12b of the substrate 12 by a conductive adhesive portion 16a. The conductive adhesive portion 16a is formed to extend to the radially outer position of the overlapping portion 15bdf. In this modified example, the substrate wiring 14b is arranged on the front surface 12a, but the substrate wiring can also be arranged on the back surface 12b and connected to the column wiring 15a via the conductive overlapping portion 15bdf and the conductive adhesive portion 16a.

[0059] Figure 11 is a schematic cross-sectional view showing a modified example of the capacitive sensor of this embodiment. In this modified example, the substrate 12r has a curved shape as shown in Figure 11. Also, in this modified example, the partial overlap 15dfp differs from the overlap 15df shown in Figures 2 and 6 in that it is formed only on a portion of the circumferential direction. Note that electrodes 13, 14 and wirings 13a, 14a, 14b, 15a are omitted from the illustration in the figures. The partial overlap 15dfp extends in a substantially linear shape along one radial direction with respect to the central axis of the through hole 17. The length of the partial overlap 15dfp in the radial direction is the same as the radial length of the overlap 15df shown in Figures 2 and 6.

[0060] Furthermore, as shown in Figure 11, the partial overlap portions 15dfp formed on adjacent pillars 15 can extend in opposite directions. In this modified example, if the surface 12a of the substrate 12 located near the center of the two pillars 15 protrudes toward the electrode-embedded portion 11, the partial overlap portions 15dfp formed on adjacent pillars 15 can be formed in directions away from the center of the two pillars 15. This makes it difficult for the flexible member 15A to come out of the through hole 17 when an external load F is applied in such a way that the flexible member 15A is peeled away from the substrate 12r.

[0061] In this modified example, if multiple pillars 15 have overlapping portions 15dfp, it is preferable that the direction in which the overlapping portions 15dfp extend differs for pillars 15 located in close proximity to each other. This prevents all overlapping portions 15dfp from simultaneously coming out of the through-hole 17, regardless of the direction of the applied external load F. If multiple pillars 15 have overlapping portions 15dfp, it is also possible to randomly set the direction in which the overlapping portions 15dfp extend.

[0062] Furthermore, if the overlapping portion 15dfp is sized to pass through the through-hole 17, it can be bonded to the back surface 12b of the substrate 12 using the adhesive portion 16. Alternatively, during assembly, the overlapping portion 15dfp can be assembled so that it passes through the through-hole 17, thereby reducing the number of manufacturing steps.

[0063] Furthermore, in this embodiment, the substrate 12 is configured as a flat rigid substrate or the like, but the following configurations are also possible. The substrate can be configured with stretchable wiring for direct attachment to surfaces such as the human body, as part of the outer surface of a robot's casing, as a metal frame, as a functional flexible fabric made of fibers, and can also be used on the surface of electronic devices, the surface of functional furniture such as sofas, beds, and cushions, as well as insoles for shoes, and handlebars for cars, motorcycles, and bicycles.

[0064] A second embodiment of the capacitive sensor according to the present invention will be described below with reference to the drawings. Figure 12 is a schematic cross-sectional view showing the capacitive sensor in this embodiment. In this embodiment, the only difference from the first embodiment described above is the arrangement of the cover and wiring. Other components corresponding to the first embodiment described above are denoted by the same reference numerals and their descriptions are omitted.

[0065] In this embodiment, the capacitive sensor 10 has a cover portion 15uf, as shown in Figure 12. The cover portion 15uf is formed near the end of the pillar 15. The cover portion 15uf contacts the outer edge of the through hole 17 on the surface 12a of the substrate 12. The cover portion 15uf is located along the outer edge of the through hole 17 along the surface 12a of the substrate 12. The cover portion 15uf is formed in a flange shape with an enlarged diameter relative to the pillar 15. The cover portion 15uf is formed in a flange shape with an enlarged diameter relative to the through hole 17. If the diameter of the through-hole 17 is larger than the diameter of the pillar 15, the cover portion 15uf may be omitted.

[0066] The diameter of the cover portion 15uf is larger than the diameter of the through hole 17. The diameter of the cover portion 15uf is larger than the diameter of the pillar 15. The diameter of the cover portion 15uf is the same as or different from the diameter of the overlapping portion 15df. The diameter of the cover portion 15uf may be smaller than the diameter of the overlapping portion 15df. The diameter of the cover portion 15uf may be larger than the diameter of the overlapping portion 15df.

[0067] The thickness of the cover portion 15uf is the same as or different from the thickness of the overlapping portion 15df. The thickness of the cover portion 15uf may be less than the thickness of the overlapping portion 15df. The thickness of the cover portion 15uf may be less than the thickness of the overlapping portion 15df. The cover portion 15uf has the same thickness in all directions. The cover portion 15uf has the same thickness in all directions.

[0068] The cover portion 15uf is formed integrally with the pillar 15. The cover portion 15uf is formed from a flexible member 15A which is the same material as the pillar 15. If a flexible column wiring 15a is formed on the pillar 15, the cover portion 15uf may have a portion formed from the same material as the column wiring 15a.

[0069] The cover portion 15uf can also be bonded to the surface 12a of the substrate 12 by an adhesive portion 16. The cover portion 15uf is bonded to the surface 12a of the substrate 12 via the adhesive portion 16 in all pillars 15. Alternatively, some of the pillars 15 may not have a cover portion 15uf bonded to the surface 12a of the substrate 12.

[0070] In this embodiment, electrical conductivity is established between the flexible material 15A and the substrate 12 near the through hole 17. The conductive portion between the flexible material 15A and the substrate 12 is formed by a deformable conductive portion on the flexible material 15A, so that the conductive state is maintained even when the flexible material 15A is deformed. Specifically, as shown in Figure 12, the substrate 12 has substrate surface wiring 14b, inner perimeter wiring 14h, and substrate back wiring 14d formed on it.

[0071] The substrate surface wiring 14b is formed on the surface 12a which forms the outer edge of the through hole 17. The back wiring 14d of the circuit board is formed on the back surface 12b, which is the outer edge of the through hole 17. The inner circumferential wiring 14h is formed on the inner surface of the through hole 17. The inner circumferential wiring 14h is connected to the substrate front wiring 14b and the substrate back wiring 14d at both axial ends of the through hole 17, respectively. The inner circumferential wiring 14h does not necessarily have to be connected to the substrate front wiring 14b and the substrate back wiring 14d at both axial ends of the through hole 17. The circuit board surface wiring 14b, the inner perimeter wiring 14h, and the circuit board back wiring 14d are electrically conductive to each other. The circuit board surface wiring 14b and the circuit board back wiring 14d are electrically conductive through the inner perimeter wiring 14h.

[0072] Similarly, the pillar 15 has cover wiring (flexible wiring, conductive) 15auf, hole wiring (flexible wiring, conductive) 15ah, and overlapping wiring (flexible wiring, conductive) 15adf. Note that column wiring 15a is also formed on the pillar 15, but it is not shown here.

[0073] The cover portion wiring 15auf is formed on the cover portion 15uf. The cover portion wiring 15auf is formed on the flange surface of the cover portion 15uf, which is located opposite the surface 12a. The internal wiring 15ah is formed on the outer surface of the flexible material 15A located inside the through hole 17. The overlapping wiring 15adf is formed on the overlapping portion 15df. The overlapping wiring 15adf is formed on the flange surface of the overlapping portion 15df, which is located opposite the back surface 12b.

[0074] The cover wiring 15auf, the hole wiring 15ah, and the overlapping wiring 15adf are electrically conductive to each other. The cover wiring 15auf and the overlapping wiring 15adf are electrically conductive to each other via the hole wiring 15ah. Alternatively, the cover wiring 15auf, the hole wiring 15ah, and the overlapping wiring 15adf may be connected to each other via a column wiring 15a, which is not shown. Alternatively, the cover portion 15uf and the overlapping portion 15df can be formed from the same conductive material, including the end of the pillar 15.

[0075] The substrate surface wiring 14b and the cover wiring 15auf are positioned opposite each other. When no external load F is applied, the substrate surface wiring 14b and the cover wiring 15auf are in contact with each other. In this case, the planes of the substrate surface wiring 14b and the cover wiring 15auf along the surface 12a are in contact with each other. The substrate surface wiring 14b and the cover wiring 15auf, which are in contact, are electrically conductive with each other.

[0076] The inner circumferential wiring 14h and the inner wiring 15ah are positioned opposite each other. The inner circumferential wiring 14h and the inner wiring 15ah are in contact with each other when no external load F is applied. In this case, the cylindrical surfaces of the inner circumferential wiring 14h and the inner wiring 15ah are in contact with each other around the axis of the through hole 17. The inner circumferential wiring 14h and the inner wiring 15ah, which are in contact with each other, are electrically conductive to each other.

[0077] The back-mount wiring 14d and the overlapping wiring 15adf are positioned opposite each other. The back-mount wiring 14d and the overlapping wiring 15adf are in contact with each other when no external load F is applied. In this case, the planes along the back surface 12b of the back-mount wiring 14d and the overlapping wiring 15adf are in contact with each other. The back-mount wiring 14d and the overlapping wiring 15adf, which are in contact with each other, are electrically conductive to each other.

[0078] When no external load F is applied, the circuit board surface wiring 14b and the cover wiring 15auf, the inner perimeter wiring 14h and the inner hole wiring 15ah, and the circuit board back wiring 14d and the overlapping wiring 15adf are all electrically connected. Furthermore, the circuit board surface wiring 14b and the cover wiring 15auf, the inner perimeter wiring 14h and the inner hole wiring 15ah, and the circuit board back wiring 14d and the overlapping wiring 15adf all have contact resistance.

[0079] Here, the contact resistance of each component when no external load F is applied is taken as the reference value. Then, when the cover wiring 15auf, the hole wiring 15ah, and the overlapping wiring 15adf are compressed, their contact resistance becomes smaller than the reference value. Compression of the cover wiring 15auf, the hole wiring 15ah, and the overlapping wiring 15adf occurs, for example, when an external load F is applied and the flexible material 15A deforms.

[0080] Furthermore, when an external load F is applied and the flexible material 15A deforms, there is a possibility that one or more of the following may separate from each other and cause a loss of conductivity: the surface wiring 14b and cover wiring 15auf, the inner peripheral wiring 14h and inner wiring 15ah, and the back wiring 14d and overlapping wiring 15adf of the substrate. Such deformation will be explained below.

[0081] Figure 13 is a schematic cross-sectional view showing the state in which an external load F is applied to the capacitive sensor in this embodiment. In Figure 13, the direction in which the electrode-embedded portion 11 moves toward the surface 12a of the substrate 12 is defined as the +Z direction. The direction along the surface 12a of the substrate 12 is defined as the +XY direction. The +XY direction is one of the directions along the surface 12a.

[0082] As shown in Figure 13, when an external load F in the +Z direction is applied to the capacitive sensor 10, the electrode-embedded portion 11 deforms so that it approaches the surface 12a of the substrate 12. Consequently, the pillar 15 is pressed in the +Z direction. As a result, the cover portion 15uf and the overlapping portion 15df are pressed in the +Z direction. At this time, the substrate 12 does not deform, so the cover portion 15uf and the overlapping portion 15df deform so that their centers move in the +Z direction.

[0083] In this process, the cover portion 15uf deforms due to the external load F in the +Z direction, causing it to be pressed against the surface 12a of the substrate 12. The deformation of the cover portion 15uf due to the external load F in the +Z direction causes the cover portion wiring 15auf to be pressed against the substrate surface wiring 14b. The cover portion wiring 15auf is compressed, increasing the density of conductive particles.

[0084] Similarly, an external load F in the +Z direction deforms the overlapping portion 15df so that it moves away from the back surface 12b of the substrate 12. Due to the deformation of the overlapping portion 15df caused by the external load F in the +Z direction, the overlapping portion wiring 15adf stretches so that it peels away from the substrate back surface wiring 14d. The overlapping portion wiring 15adf is stretched, and the density of conductive particles decreases. In this case, an external load F in the +Z direction generates a frictional force that causes the inner circumferential wiring 14h and the inner wiring 15ah to move relative to each other in the +Z direction. Even if the inner circumferential wiring 14h and the inner wiring 15ah are displaced in the +Z direction, the contact area hardly changes.

[0085] When the external load F is less than the threshold, the deformation of the flexible member 15A slightly reduces the resistance of the compressed cover wiring 15auf. At the same time, the contact resistance between the compressed cover wiring 15auf and the substrate surface wiring 14b slightly decreases. Similarly, the deformation of the flexible member 15A slightly increases the resistance of the stretched overlapping wiring 15adf. At the same time, the contact resistance between the stretched overlapping wiring 15adf and the back-mounted wiring 14d of the substrate slightly increases.

[0086] Even if the relative positions shift slightly due to the deformation of the flexible member 15A, the contact resistance between the inner circumferential wiring 14h and the inner wiring 15ah remains almost unchanged. Thus, when the external load F is smaller than the threshold, the decrease in resistance between the cover wiring 15auf and the substrate front wiring 14b cancels out the increase in resistance between the overlapping wiring 15adf and the substrate back wiring 14d. Therefore, there is almost no change in the electrical conductivity state, and it has no significant impact.

[0087] In contrast, when an external load F in the +Z direction greater than the threshold is applied, the deformation of the flexible member 15A further reduces the resistance of the compressed cover wiring 15auf. At the same time, the contact resistance between the compressed cover wiring 15auf and the substrate surface wiring 14b is further reduced. Similarly, an external load F in the +Z direction greater than the threshold causes the overlapping portion 15df to peel off from the back surface 12b of the substrate 12. Due to the peeling of the overlapping portion 15df caused by the external load F in the +Z direction, the overlapping portion wiring 15adf separates from the substrate back surface wiring 14d. Note that in Figure 13, the peeled portion of the overlapping portion wiring 15adf is not shown because it does not contribute to conductivity. An external load F in the +Z direction greater than the threshold causes only a slight shift in the relative position between the inner circumferential wiring 14h and the inner wiring 15ah. The deformation of the flexible member 15A causes almost no change in the contact resistance between the inner circumferential wiring 14h and the inner wiring 15ah.

[0088] When the external load F in the +Z direction is greater than the threshold, the decrease in resistance between the cover wiring 15auf and the substrate front wiring 14b and the increase in resistance due to delamination between the overlapping wiring 15adf and the substrate back wiring 14d are almost completely offset. Therefore, the change in electrical conductivity is only slight and does not have a significant impact.

[0089] In this embodiment, even when an external load F in the +Z direction is applied to the capacitive sensor, the change in resistance due to the deformation of the flexible material 15A is canceled out in each part, and there is no significant effect on the electrical conductivity. Therefore, the external load F can be measured while maintaining stable detection characteristics and high durability.

[0090] Figure 14 is a schematic cross-sectional view showing the state in which an external load F is applied to the capacitive sensor in this embodiment.

[0091] As shown in Figure 14, when an external load F in the -Z direction is applied to the capacitive sensor 10, the electrode-embedded portion 11 deforms in a direction that separates it from the surface 12a of the substrate 12. Consequently, the pillar 15 is pulled in the -Z direction. Then, the cover portion 15uf and the overlapping portion 15df are pulled in the -Z direction. At this time, the substrate 12 does not deform, so the cover portion 15uf and the overlapping portion 15df deform such that their centers move in the -Z direction.

[0092] In this process, the external load F in the -Z direction deforms the cover portion 15uf so that it separates from the surface 12a of the substrate 12. Due to the deformation of the cover portion 15uf caused by the external load F in the -Z direction, the cover portion wiring 15auf stretches as if being peeled away from the substrate surface wiring 14b. The cover portion wiring 15auf is stretched, and the density of conductive particles decreases. Similarly, an external load F in the -Z direction causes the overlapping portion 15df to be pressed against the back surface 12b of the substrate 12 and deformed. The deformation of the overlapping portion 15df due to the external load F in the -Z direction causes the overlapping portion wiring 15adf to be pressed against the substrate back surface wiring 14d. The overlapping portion wiring 15adf is compressed, increasing the density of conductive particles.

[0093] In this case, an external load F in the -Z direction generates a frictional force that causes the inner circumferential wiring 14h and the inner wiring 15ah to move relative to each other in the -Z direction. Even if the inner circumferential wiring 14h and the inner wiring 15ah are displaced in the -Z direction, the contact area hardly changes.

[0094] When the external load F is less than the threshold, the deformation of the flexible member 15A slightly increases the resistance of the stretched cover wiring 15auf. At the same time, the contact resistance between the enlarged cover wiring 15auf and the substrate surface wiring 14b slightly increases. Similarly, the deformation of the flexible member 15A slightly reduces the resistance of the compressed overlapping wiring 15adf. At the same time, the contact resistance between the pressed overlapping wiring 15adf and the back-mounted wiring 14d of the substrate is slightly reduced.

[0095] Even if the relative positions shift slightly due to the deformation of the flexible member 15A, the contact resistance between the inner circumferential wiring 14h and the inner wiring 15ah remains almost unchanged. Thus, when the external load F is smaller than the threshold, the increase in resistance between the cover wiring 15auf and the substrate front wiring 14b cancels out the decrease in resistance between the overlapping wiring 15adf and the substrate back wiring 14d. Therefore, there is almost no change in the electrical conductivity state, and it has no significant impact.

[0096] In contrast, when an external load F in the -Z direction greater than the threshold is applied, the flexible member 15A deforms, causing the cover wiring 15auf to peel off from the surface 12a of the substrate 12. The resistance value decreases further. At the same time, the cover wiring 15auf separates from the substrate surface wiring 14b. Note that in Figure 14, the detached portion of the cover wiring 15auf is not shown because it does not contribute to conductivity.

[0097] Similarly, an external load F in the -Z direction greater than the threshold presses the overlap 15df against the back surface 12b of the substrate 12. Compression of the overlap 15df by the external load F in the +Z direction further reduces the resistance of the overlap wiring 15adf. At the same time, the contact resistance between the compressed overlap wiring 15adf and the substrate back wiring 14d is further reduced. An external load F in the -Z direction greater than the threshold causes only a slight shift in the relative position between the inner circumferential wiring 14h and the inner wiring 15ah. The deformation of the flexible member 15A causes almost no change in the contact resistance between the inner circumferential wiring 14h and the inner wiring 15ah.

[0098] -When the external load F in the Z direction is greater than the threshold, the increase in resistance between the cover wiring 15auf and the substrate front wiring 14b and the decrease in resistance due to delamination between the overlapping wiring 15adf and the substrate back wiring 14d are almost offset. Therefore, the change in electrical conductivity is slight and does not have a significant impact.

[0099] In this embodiment, even when an external load F in the -Z direction is applied to the capacitive sensor, the change in resistance due to the deformation of the flexible material 15A is canceled out in each part, and there is no significant effect on the electrical conductivity. Therefore, the external load F can be measured while maintaining stable detection characteristics and high durability.

[0100] Figure 15 is a schematic cross-sectional view showing the state in which an external load F is applied to the capacitive sensor in this embodiment.

[0101] As shown in Figure 15, when an external load F in the +XY direction is applied to the capacitive sensor 10, the electrode-embedded portion 11 deforms along the surface 12a of the substrate 12 in the +XY direction. Consequently, the pillar 15 is pulled in the +XY direction. As a result, the cover portion 15uf and the overlapping portion 15df are pulled in the +XY direction. At this time, the substrate 12 does not deform, so the cover portion 15uf and the overlapping portion 15df deform to move in the +XY direction.

[0102] In this process, the cover portion 15uf and the overlapping portion 15df are deformed by the external load F in the +XY direction so that they move along the surface 12a of the substrate 12 in the +XY direction. Due to the deformation of the cover portion 15uf caused by an external load F in the +XY direction, the cover portion wiring 15auf moves relative to the substrate surface wiring 14b in the +XY direction.

[0103] Similarly, due to the deformation of the overlapping portion 15df by an external load F in the +XY direction, the overlapping portion wiring 15adf moves relative to the substrate back wiring 14d in the +XY direction. Since the cover portion wiring 15auf and the overlapping portion wiring 15adf are neither compressed nor stretched, the density of conductive particles does not change. The resistance between the cover portion wiring 15auf and the substrate front wiring 14b, and the resistance between the overlapping portion wiring 15adf and the substrate back wiring 14d, hardly change.

[0104] At this time, the internal wiring 15ah is pressed in the +XY direction by the external load F in the +XY direction. As a result, the portion of the internal wiring 15ah that is in the +XY direction in the circumferential direction is pressed toward the internal circumferential wiring 14h. Also, the portion of the internal wiring 15ah that is in the opposite direction to the +XY direction in the circumferential direction is pulled away from the internal circumferential wiring 14h. In the in-hole wiring 15ah, the density of conductive particles increases in the compressed area and decreases in the stretched area. As a result, the resistance of the in-hole wiring 15ah decreases in the compressed area and increases in the stretched area.

[0105] When the external load F in the +XY direction is less than the threshold, the increase or decrease in resistance in the in-hole wiring 15ah caused by the deformation of the flexible member 15A is offset. Furthermore, in the cover section wiring 15auf and the overlapping section wiring 15adf, there is almost no change in resistance value.

[0106] If the external load F in the +XY direction is greater than the threshold, similarly, the portion of the in-hole wiring 15ah that is in the circumferential +XY direction is further pressed toward the in-hole circumferential wiring 14h. Also, the portion of the in-hole wiring 15ah that is in the opposite direction to the circumferential +XY direction is pulled away from the in-hole circumferential wiring 14h and separates. In the pressed portion of the in-hole wiring 15ah, the resistance decreases, and in the pulled-away portion, the contact area becomes zero. In Figure 15, the portion of the detached in-hole wiring 15ah is not shown because it does not contribute to conductivity.

[0107] If the external load F in the +XY direction is greater than the threshold, the cover wiring 15auf moves relative to the board surface wiring 14b in the +XY direction. The overlapping wiring 15adf moves relative to the board surface wiring 14d in the +XY direction. However, the resistance between the cover wiring 15auf and the board surface wiring 14b, and the resistance between the overlapping wiring 15adf and the board surface wiring 14d, hardly change.

[0108] In this embodiment, even when an external load F in the +XY direction is applied to the capacitive sensor, the change in resistance due to the deformation of the flexible material 15A is canceled out in each part, and does not have a significant effect on the electrical conductivity. Therefore, the external load F can be measured while maintaining stable detection characteristics.

[0109] Figure 16 is a schematic cross-sectional view showing the state in which an external load F is applied to the capacitive sensor in this embodiment. As shown in Figure 16, when an external load F in the -XY direction is applied to the capacitive sensor 10, the effect of deformation is reversed compared to when an external load F in the +XY direction is applied, but other effects remain unchanged. Therefore, the change in resistance due to the deformation of the flexible material 15A cancels out in each part, and does not have a significant effect on the electrical conductivity. As a result, accurate measurement of the external load F can be performed while maintaining stable detection characteristics and high durability.

[0110] Figure 17 is a schematic cross-sectional view showing a conventional capacitive sensor with an external load F applied to it. As shown in Figure 17, in conventional capacitive sensors, when a large external load F in the -XY direction is applied, the conductive adhesive portion 16a peels off. Moreover, since the conductive portion other than the conductive adhesive portion 16a is lost, a disconnection occurs. In contrast, the capacitive sensor 10 in this embodiment can prevent disconnection.

[0111] Figure 18 is a schematic cross-sectional view showing the state in which an external load F is applied to the capacitive sensor in this embodiment.

[0112] As shown in Figure 18, when an external load F having components in the +Z direction and the +XY direction is applied to the capacitive sensor 10, the electrode housing portion 11 deforms in a direction that brings it closer to the surface 12a of the substrate 12, and the electrode housing portion 11 deforms in the +XY direction along the surface 12a of the substrate 12, simultaneously. Consequently, the pillar 15 is compressed in the +Z direction and stretched in the +XY direction.

[0113] As a result, the substrate 12 does not deform, and the cover portion 15uf and the overlapping portion 15df are pressed in the +Z direction near their centers, while the cover portion 15uf and the overlapping portion 15df are pulled in the +XY direction. At the same time, the in-hole wiring 15ah is pressed in the +XY direction. In Figure 18, the detached in-hole wiring 15ah and the overlapping portion wiring 15adf are not shown because they do not contribute to conductivity.

[0114] When an external load F having components in the +Z direction and the +XY direction is applied, the effects of the +Z direction external load F and the +XY direction external load F occur simultaneously. As a result, the decrease in resistance between the cover wiring 15auf and the substrate front wiring 14b, the increase in resistance between the overlapping wiring 15adf and the substrate back wiring 14d, and the increase or decrease in resistance between the inner periphery wiring 14h and the inner wiring 15ah are all almost canceled out. Therefore, the change in electrical conductivity is only slight and does not have a significant impact.

[0115] This means that the magnitude of the external load F, which has components in the +Z direction and the +XY direction, is not affected by its magnitude relative to the threshold at which peeling occurs. Therefore, the external load F can be measured while maintaining stable detection characteristics and high durability.

[0116] Figure 19 is a schematic cross-sectional view showing the state in which an external load F is applied to the capacitive sensor in this embodiment.

[0117] As shown in Figure 19, when an external load F having components in the -Z direction and the -XY direction is applied to the capacitive sensor 10, the electrode housing portion 11 deforms in a direction that separates it from the surface 12a of the substrate 12, and the electrode housing portion 11 deforms in the -XY direction along the surface 12a of the substrate 12, simultaneously. Consequently, the pillar 15 is pulled in both the -Z direction and the -XY direction.

[0118] As a result, the substrate 12 does not deform, and the cover portion 15uf and the overlapping portion 15df are pulled in the -Z direction near their centers, and the cover portion 15uf and the overlapping portion 15df are pulled in the -XY direction. At the same time, the in-hole wiring 15ah is pressed in the -XY direction. In Figure 19, the detached in-hole wiring 15ah and cover portion wiring 15auf are not shown because they do not contribute to conductivity.

[0119] When an external load F having components in the -Z direction and the -XY direction is applied, the effects of the -Z direction external load F and the -XY direction external load F occur simultaneously. As a result, the increase in resistance between the cover wiring 15auf and the substrate front wiring 14b, the decrease in resistance between the overlapping wiring 15adf and the substrate back wiring 14d, and the increase or decrease in resistance between the inner periphery wiring 14h and the inner wiring 15ah are all almost canceled out. Therefore, the change in electrical conductivity is slight and does not have a significant impact.

[0120] This means that the magnitude of the external load F, which has components in the -Z direction and the -XY direction, is not affected by its magnitude relative to the threshold at which peeling occurs. Therefore, the external load F can be measured while maintaining stable detection characteristics and high durability.

[0121] Figure 20 is a schematic cross-sectional view showing the state in which an external load F is applied to the capacitive sensor in this embodiment.

[0122] As shown in Figure 20, when an external load F having a +Z component and a -XY component is applied to the capacitive sensor 10, the electrode housing 11 deforms in a direction that brings it closer to the surface 12a of the substrate 12, and the electrode housing 11 deforms in the -XY direction along the surface 12a of the substrate 12 simultaneously. Consequently, the pillar 15 is pressed in the +Z direction and pulled in the -XY direction.

[0123] As a result, the substrate 12 does not deform, and the cover portion 15uf and the overlapping portion 15df are pulled in the +Z direction near their centers, and the cover portion 15uf and the overlapping portion 15df are pulled in the -XY direction. At the same time, the in-hole wiring 15ah is pressed in the -XY direction. In Figure 20, the detached in-hole wiring 15ah and the overlapping portion wiring 15adf are not shown because they do not contribute to conductivity.

[0124] When an external load F having components in the +Z direction and the -XY direction is applied, the effects of the +Z direction external load F and the -XY direction external load F occur simultaneously. As a result, the decrease in resistance between the cover wiring 15auf and the substrate front wiring 14b, the increase in resistance between the overlapping wiring 15adf and the substrate back wiring 14d, and the increase or decrease in resistance between the inner periphery wiring 14h and the inner wiring 15ah are all almost canceled out. Therefore, the change in electrical conductivity is only slight and does not have a significant impact.

[0125] This means that the magnitude of the external load F, which has components in the +Z direction and -XY direction, is not affected by its magnitude relative to the threshold at which peeling occurs. Therefore, the external load F can be measured while maintaining stable detection characteristics and high durability.

[0126] Figure 21 is a schematic cross-sectional view showing the state in which an external load F is applied to the capacitive sensor in this embodiment.

[0127] As shown in Figure 21, when an external load F having a -Z component and a +XY component is applied to the capacitive sensor 10, the electrode housing 11 deforms in a direction that separates it from the surface 12a of the substrate 12, and the electrode housing 11 deforms in the +XY direction along the surface 12a of the substrate 12 simultaneously. Consequently, the pillar 15 is pulled in both the -Z direction and the +XY direction.

[0128] As a result, since the substrate 12 does not deform, the cover portion 15uf and the overlapping portion 15df are pulled in the -Z direction near their centers, and the cover portion 15uf and the overlapping portion 15df are pulled in the +XY direction. At the same time, the in-hole wiring 15ah is pressed in the +XY direction. In Figure 21, the detached in-hole wiring 15ah and cover portion wiring 15auf are not shown because they do not contribute to conductivity.

[0129] When an external load F having components in the -Z direction and the +XY direction is applied, the effects of the external load F applied in the -Z direction and the effects of the external load F applied in the +XY direction occur simultaneously. As a result, the increase in resistance between the cover wiring 15auf and the substrate front wiring 14b, the decrease in resistance between the overlapping wiring 15adf and the substrate back wiring 14d, and the increase or decrease in resistance between the inner periphery wiring 14h and the inner wiring 15ah are all almost canceled out. Therefore, the change in electrical conductivity is slight and does not have a significant impact.

[0130] This means that the magnitude of the external load F, which has components in the -Z direction and the +XY direction, is not affected by its magnitude relative to the threshold at which peeling occurs. Therefore, the external load F can be measured while maintaining stable detection characteristics and high durability.

[0131] Figure 22 is a graph illustrating the relationship between external force and resistance in the capacitive sensor of this embodiment. In Figure 22, the vertical axis represents the resistance value R. The horizontal axis represents the change in the magnitude of the external load (external force) in the +XY direction. The horizontal axis in Figure 22 shows that from left to right, the magnitude of the applied external load F changes from -Fxy to +Fxy, beyond the origin O. At the origin O, the external load F in the +XY direction is zero.

[0132] In the capacitive sensor 10 of this embodiment, as shown in Figure 22, the resistance value R when the direction of the external load F changes along the horizontal axis from the -XY direction to the +XY direction is approximately constant, although there are some increases and decreases. Furthermore, the magnitude of the external load F shown does not exceed the peeling limit. Also, the magnitude of the external load F shown does not exceed the threshold of contact resistance.

[0133] In contrast, with conventional capacitive sensors, as shown in Figure 22, the resistance value R when the direction of the external load F changes along the horizontal axis from the -XY direction to the +XY direction is lower than that of the capacitive sensor 10 of this embodiment near the origin O. However, as the external load F increases, it rises sharply regardless of whether the increase is in the -Fxy or +Fxy direction. This indicates that as the magnitude of the external load F approaches the value at which delamination occurs, the resistance value R rises sharply, exceeding the threshold of contact resistance.

[0134] This demonstrates that, in the capacitive sensor 10 of this embodiment, even if an external force is applied and a gap is created between the flexible conductive pillar 15a and the through-hole 17 on the substrate 12, contact can be maintained at one or more points. Here, the formation of gaps due to the separation of flexible wiring and substrate wiring is a factor that increases resistance. On the other hand, the compression of the flexible conductive pillar and the decrease in contact resistance due to the flexible conductor being pressed against the through-hole are factors that decrease resistance. Due to these factors, in the capacitive sensor 10 of this embodiment, the increase in resistance and the decrease in resistance cancel each other out, and the resistance value does not increase significantly and is kept below the threshold.

[0135] Furthermore, in the present invention, it is also possible to individually select and combine each of the configurations in the above-described embodiments. [Explanation of symbols]

[0136] 10…Capacitive Sensor 11… Electrode-integrated section 12,12r… circuit board 12a…Surface (first side) 12b…Reverse side (second side) 13…Flexible electrode (second electrode) 13a... Flexible wiring (conductive material) 14...Substrate electrode (first electrode) 14a, 14b... PCB surface wiring (PCB wiring, conductive parts) 14d... Circuit board back wiring (circuit board wiring, conductive parts) 14h...Circumferential wiring around holes (circuit board wiring, conductive parts) 15…Pillar (column) 15A... Flexible material 15a... Pole wiring (flexible wiring, conductive material) 15adf… Overlapping wiring (flexible wiring, conductive material) 15ah…In-hole wiring (flexible wiring, conductive material) 15auf…Cover section wiring (flexible wiring, conductive material) 15df... overlapping part 15dfp...partial overlap 15uf…cover part 16...Adhesive part 16a…Conductive adhesive part 17…Through hole 19…Control Unit

Claims

1. Circuit board (12) and A first electrode (14) is provided on the first surface (12a) of the substrate (12), A flexible member (15A) having elasticity is fixed to the substrate (12), A second electrode (13) is provided within the flexible member (15A) so as to face the first electrode (14) while maintaining a distance between it and the first electrode (14), and is used to detect the capacitance between the second electrode (13) and the first electrode (14). Equipped with, The flexible member (15A) is The electrode housing portion (11) incorporates the second electrode (13) and has a gap between it and the surface (12a) of the substrate (12), A columnar portion (15) extending between the electrode-integrated portion (11) and the substrate (12), The column portion (15) passing through the through hole (17) that penetrates the substrate (12) has an overlapping portion (15df) on the second surface (12b) of the substrate (12) opposite to the first surface (12a) that overlaps the outer edge of the through hole (17), It has, Capacitive sensor.

2. In the capacitive sensor according to claim 1, The flexible member (15A) is formed from a dielectric material. Capacitive sensor.

3. In the capacitive sensor according to claim 1, The substrate (12) has conductive portions (14a, 14b), The column portion (15) has a conductor (15a) that connects the second electrode (13) and the conductive portions (14a, 14b). Capacitive sensor.

4. In the capacitive sensor according to claim 1, The column portion (15) has a cover portion (15uf) on the first surface (12a) of the substrate (12) that covers the outer edge of the through hole (17). Capacitive sensor.

5. In the capacitive sensor according to claim 3, The conductive portion (14b to 14d) is provided on at least one portion of the inner circumferential surface of the through hole (17) of the substrate (12), the outer edge of the through hole (17) on the first surface (12a) of the substrate (12), and the outer edge of the through hole (17) on the second surface (12b) of the substrate (12), and is electrically connected to the conductor (15a) of the column portion (15). Capacitive sensor.

6. In the capacitive sensor according to claim 1, The overlapping portion (15df) is formed around the entire outer edge of the through hole (17), or on a portion of the outer edge of the through hole (17) in the circumferential direction. Capacitive sensor.

7. In the capacitive sensor according to claim 1, Multiple columnar portions (15) are formed, The through holes (17) are formed in multiple locations. Capacitive sensor.

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