Shear force sensor

Abstract

To reduce detection errors and sensitivity degradation of shear force detection caused by wiring for connecting driving and detection electrodes of a shear force sensor to an external circuit, and to make the wiring resistant to damage.SOLUTION: A first base film 10 includes a deformation-allowable unit 15, which is separated from a pressure receiving region PA by a first slit SL1 formed in the first base film 10 and is deformable by a small force. The deformation-allowable part 15 is separated by the first slit SL1 so that the deformation-allowable part is disposed along an edge of the pressure receiving region PA so as to be connected to a connection member placement region CA and the pressure receiving region PA.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a shear force sensor. [Background technology]

[0002] As described in Patent Document 1 (Japanese Patent No. 7213921), some conventional shear force sensors have a structure in which an elastic sheet is sandwiched between a driving electrode and a detection electrode. Shear force sensors with this structure detect the magnitude of the force applied in the in-plane direction of the elastic sheet of the shear force sensor based on the magnitude of the positional deviation of the detection electrode relative to the driving electrode. Some conventional shear force sensors can detect not only the magnitude of the force applied in the in-plane direction of the elastic sheet, but also the magnitude of the force in the direction perpendicular to the surface. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7213921 Summary of the Invention [Problem to be solved by the invention]

[0004] In a shear force sensor such as that disclosed in Patent Document 1, the driving electrode and the detection electrode are electrically connected to a terminal portion via wiring. The terminal portion is connected to a detection circuit for detecting by the shear force sensor. However, if the wiring portion, including the terminal portion, is made thin, the wiring becomes more susceptible to damage. Conversely, if the wiring portion is made thicker, the wiring portion acts to prevent the detection electrode from shifting relative to the driving electrode due to shear force, which can cause errors and reduced sensitivity.

[0005] The objective of the present invention is to make the wiring connecting the drive electrode and detection electrode of the shear force sensor to an external circuit less susceptible to damage, and to reduce errors in shear force detection and reduced sensitivity that arise from providing wiring connecting the shear force sensor to an external circuit. [Means for solving the problem]

[0006] Below, several aspects will be described as means for solving the problems. These aspects can be arbitrarily combined as necessary. A shear force sensor according to a first aspect of the present invention includes a first base film, a second base film, an elastic sheet, an extraction film, and a connecting member. The first base film is provided with a detection electrode and a first lead-out wiring connected to the detection electrode. The second base film is provided with a drive electrode facing the detection electrode and a second lead-out wiring connected to the drive electrode. The elastic sheet is disposed between the detection electrode and the drive electrode, and is bonded to the first base film and the second base film. The elastic sheet is elastically deformed by stress applied between the first base film and the second base film. The extraction film is provided with a first lead-out wiring corresponding to the first lead-out wiring and a second lead-out wiring corresponding to the second lead-out wiring, as well as terminal portions for electrically connecting the first lead-out wiring and the second lead-out wiring to the outside. The connecting member electrically connects the first lead-out wiring and the first lead-out wiring, and fixes the first base film to the extraction film. The first base film has a pressure-receiving area where the detection electrodes are arranged, a connection member arrangement area where the connection members are arranged, and a deformable portion where a first wiring line extending from the connection member arrangement area to the pressure-receiving area is arranged. The first base film has a first slit extending between the connection member arrangement area and the deformable portion and the pressure-receiving area, separating the connection member arrangement area and the deformable portion from the pressure-receiving area.

[0007] In the shear force sensor according to the first aspect, the deformable portion separated from the pressure-receiving area by the first slit deforms with a small force, so that when a shear force is applied to the pressure-receiving area and the first base film and the second base film are displaced, the reaction that prevents the displacement caused by the fixation of the pull-out film to the first base film and the second base film can be reduced, thereby minimizing errors in shear force detection and reductions in sensitivity. Furthermore, because the deformable portion is separated by the first slit, is connected to the connection member arrangement area and the pressure-receiving area, and extends along the edge of the pressure-receiving area, damage to the wiring arranged in the deformable portion due to external forces can be suppressed.

[0008] A shear force sensor according to a second aspect is the shear force sensor according to the first aspect, wherein the deformable portion includes an unbonded region that is not bonded to the second base film. In the shear force sensor according to the second aspect, the unbonded region of the deformable portion that is not bonded to the second base film is particularly susceptible to deformation, thereby improving the effect of reducing shear force detection errors and sensitivity reductions caused by providing the deformable portion. A shear force sensor according to a third aspect is the shear force sensor according to the first or second aspect, wherein the extraction film is made of a flexible wiring board. In the shear force sensor according to the third aspect, the first and second lead-out wirings can be, for example, patterned metal wirings, making the first and second lead-out wirings less susceptible to damage.

[0009] A shear force sensor according to a fourth aspect is the shear force sensor according to the first or second aspect, configured such that the first base film and the pull-out film, or the second base film and the pull-out film, are formed from a single film. In the shear force sensor according to the fourth aspect, the first base film and the pull-out film or the second base film and the pull-out film are formed from a single film, which reduces material costs and labor in the manufacturing process, thereby making it easier to provide an inexpensive shear force sensor. A shear force sensor according to a fifth aspect is the shear force sensor according to any one of the first to fourth aspects, wherein the deformable portion has a bridge portion that does not overlap with the elastic sheet and overlaps with the second base film. In the shear force sensor according to the fifth aspect, since the deformable portion does not overlap with the elastic sheet, the deformable portion is easily deformed, thereby reducing detection errors in shear force and reducing sensitivity. Furthermore, since the deformable portion overlaps with the second base film, the second base film protects the wiring of the deformable portion.

[0010] A shear force sensor according to a sixth aspect is the shear force sensor according to the fifth aspect, further comprising a deformation-allowing portion adhesive that bonds a part of the deformation-allowing portion of the bridge portion to the second base film, and the deformation-allowing portion adhesive has viscoelasticity. In the shear force sensor according to the sixth aspect, a part of the deformable portion is connected to the second base film by an adhesive for the deformable portion, and the movement of the deformable portion is moderately restricted by viscoelasticity, thereby reducing the risk of damage to the wiring running through the deformable portion. A shear force sensor according to a seventh aspect is a shear force sensor according to any one of the first to fourth aspects, wherein the elastic sheet is configured to have a pressure-receiving elastic region overlapping the pressure-receiving region, a support region overlapping the deformation-allowing portion, and a second slit separating the pressure-receiving elastic region from the support region. In the shear force sensor according to the seventh aspect, the support region of the elastic sheet can protect the routing wiring of the deformable portion. Also, because the pressure-receiving elastic region and the support region are separated by the second slit in the elastic sheet, when a shear force is applied to the pressure-receiving region and the first base film and the second base film are displaced, the reaction that prevents the displacement, which occurs due to the support region of the elastic sheet and the first base film and the second base film being fixed, can be reduced, and errors in shear force detection and reductions in sensitivity can be reduced. [Effects of the Invention]

[0011] The shear force sensor according to the present invention can suppress damage to the wiring that connects the drive electrodes and detection electrodes to an external circuit, and can also reduce errors in shear force detection and sensitivity reduction that occur when providing lead-out wiring that connects the shear force sensor to an external circuit. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic plan view illustrating a configuration example of a shear force sensor according to an embodiment. [Figure 2] FIG. 2 is a schematic cross-sectional view showing a cross section of the shear force sensor of FIG. 1 taken along line II. [Figure 3] FIG. 2 is a schematic plan view illustrating a detection electrode, a drive electrode, a first lead-out wire, and a second lead-out wire of the shear force sensor. [Figure 4] FIG. 4 is a schematic cross-sectional view showing a cross section of the shear force sensor of FIG. 3 taken along line II-II. [Figure 5] FIG. 10 is a schematic cross-sectional view for explaining the capacitance generated between the drive electrode and the detection electrode of the shear force sensor during calibration. [Figure 6] FIG. 10 is a schematic cross-sectional view for explaining the capacitance generated between a drive electrode and a detection electrode of the shear force sensor when a shear force is applied. [Figure 7] FIG. 2 is a schematic exploded perspective view of the shear force sensor of FIG. 1. [Figure 8] FIG. 10 is a schematic exploded perspective view showing a configuration example of a shear force sensor according to Modification A. [Figure 9] FIG. 10 is a schematic exploded perspective view showing a configuration example of a shear force sensor according to Modification B. [Figure 10] FIG. 10 is a schematic exploded perspective view showing an example of the configuration of a shear force sensor according to Modification C. [Figure 11] 10 is a schematic plan view showing an example of the configuration of a shear force sensor according to Modification D. FIG. [Figure 12] 12 is a schematic cross-sectional view showing a cross section of the shear force sensor of FIG. 11 taken along line III-III. FIG. [Figure 13] FIG. 10 is a schematic exploded perspective view showing an example of the configuration of a shear force sensor according to Modification Example E. [Figure 14] FIG. 14 is a schematic cross-sectional view showing a cross section of the shear force sensor of FIG. 13. [Figure 15] FIG. 10 is a schematic exploded perspective view showing another example of the configuration of the shear force sensor according to Modification Example E. [Figure 16] FIG. 10 is a schematic exploded perspective view showing another example of the configuration of the shear force sensor according to Modification Example E. [Figure 17] FIG. 10 is a schematic exploded perspective view showing an example of the configuration of a shear force sensor according to Modification F. [Figure 18] FIG. 10 is a schematic exploded perspective view showing another example of the configuration of the shear force sensor according to Modification F. DETAILED DESCRIPTION OF THE INVENTION

[0013] (1) Overall structure An example of a shear force sensor according to an embodiment of the present invention is shown in Figure 1. Figure 1 is a schematic plan view of the shear force sensor. Figure 2 is a cross-sectional view of the shear force sensor 1 taken along line II in Figure 1. In Figures 1 and 2, X, Y, and Z indicate directions in the shear force sensor 1. The shear force sensor 1 includes a first base film 10, a second base film 20, an elastic sheet 30, a pull-out film 40, and a connecting member 50. The first base film 10 is provided with a detection electrode 11 and a first lead-out wiring 12. The first lead-out wiring 12 is connected to the detection electrode 11. The second base film 20 is provided with a drive electrode 21 and a second lead-out wiring 22. The drive electrode 21 faces the detection electrode 11. The second lead-out wiring 22 is connected to the drive electrode 21. The elastic sheet 30 is disposed between the detection electrode 11 and the drive electrode 21. The elastic sheet 30 is bonded to the first base film 10 and the second base film 20. The elastic sheet 30 is elastically deformed by stress applied between the first base film 10 and the second base film 20. For example, when the second base film 20 is fixed immovably to a table and the first base film 10 is pressed with a finger, the elastic sheet 30 is elastically deformed, causing the first base film 10 to shift position relative to the second base film 20 in any one of the X direction, Y direction, and Z direction, or a combination of these directions. At this time, the force generated by the elastic deformation of the elastic sheet 30 balances with the stress applied by the finger, and the shear force sensor 1 can detect the stress from the magnitude of the elastic deformation of the elastic sheet 30. The extraction film 40 is provided with first extraction wires 41, second extraction wires 42, and terminal portions 43. The first extraction wires 41 correspond to the first extraction wires 12. For example, three first extraction wires 41 are provided corresponding to the three first extraction wires 12, and two second extraction wires 42 are provided corresponding to the two second extraction wires 22. The terminal portions 43 are members that electrically connect the first extraction wires 41 and the second extraction wires 42 to the outside of the shear force sensor 1. The first extraction wiring 41 is arranged on one of the two surfaces of the extraction film 40 facing the Z direction, facing the first base film 10. The second extraction wiring 42 is arranged on one of the two surfaces of the extraction film 40, facing the second base film 20.

[0014] 2, the detection electrode 11, the first lead-out wiring 12, the drive electrode 21, the second lead-out wiring 22, the first lead-out wiring 41, and the second lead-out wiring 42 are each depicted as a single film, but in reality, these have complex shapes as shown in Figures 3 and 4. Specific configuration examples of the detection electrode 11, the first lead-out wiring 12, the drive electrode 21, the second lead-out wiring 22, the first lead-out wiring 41, and the second lead-out wiring 42 will be described later. The connection member 50 electrically connects the first lead-out wires 12 and the first lead-out wires 41. For example, when three first lead-out wires 41 are provided corresponding to the three first lead-out wires 12, the connection member 50 electrically connects each of the first lead-out wires 12 to the corresponding first lead-out wires 41. When two second lead-out wires 42 are provided corresponding to two second lead-out wires 22, the connection member 50 electrically connects each of the second lead-out wires 22 to the corresponding second lead-out wires 42. The connection member 50 fixes the lead-out film 40 to the first base film 10. In this embodiment, the connection member 50 also fixes the lead-out film 40 to the second base film 20. As will be described later, when the second base film 20 also serves as the lead-out film 40, the connection member 50 may fix the lead-out film 40 (second base film 20) only to the first base film 10.

[0015] 1, the first base film 10 has a pressure-receiving area PA. The pressure-receiving area PA is an area where a detection electrode 11 is arranged. The shear force sensor 1 detects the shear force applied to the pressure-receiving area PA. 1, the first base film 10 has a connecting member arrangement area CA. The connecting members 50 are arranged in the connecting member arrangement area CA. In other words, the area in which the connecting members 50 are arranged is defined as the connecting member arrangement area CA. The first base film 10 has a deformable portion 15 in which the first wiring lines 12 extending from the connecting member arrangement area CA to the pressure-receiving area PA are arranged. In the deformable portion 15, not all of the first wiring lines 12 but only a part of them is arranged (see FIG. 3). The first base film 10 also has a first slit SL1 shown in Figures 1 and 2. The first slit SL1 separates the connecting member arrangement area CA and the deformation allowance section 15 from the pressure-receiving area PA. For this reason, in the first base film 10, the first slit SL1 is arranged between the connecting member arrangement area CA and the deformation allowance section 15 and the pressure-receiving area PA. Since stress is likely to concentrate at a corner CR1 of the first slit SL1, it is preferable that the corner CR1 have a gentle curve, such as a circular arc, to prevent the corner CR1 from being cut due to stress (see Figure 1).

[0016] (2) Example of layout of detection electrodes, drive electrodes, and wiring 3 and 4 show examples of the patterns of the detection electrodes 11, the driving electrodes 21, the first routing wires 12, and the second routing wires 22. In Fig. 3, the first base film 10 is shown in solid lines, and the patterns of the detection electrodes 11, the driving electrodes 21, the first routing wires 12, and the second routing wires 22 are shown in dashed lines because they are covered by the first base film 10. Fig. 4 shows a cross section of the shear force sensor 1 taken along line II-II in Fig. 3. 3 and 4, the detection electrode 11 includes a first detection electrode 111 and a second detection electrode 112. The drive electrode 21 includes a first drive electrode 211 and a second drive electrode 212. A first separation groove 213 and a second separation groove 214 are formed between the first drive electrode 211 and the second drive electrode 212. The first separation groove 213 is a groove that extends in the X direction in a portion overlapping with the first detection electrode 111. The second separation groove 214 is a groove that extends straight in the Y direction in a portion overlapping with the second detection electrode 112. The pattern of the first detection electrode 111 in FIG. 3 is a pattern in which four rectangular patterns are lined up in the Y direction, and all of them are electrically connected by a thin pattern extending in the Y direction. In other words, the four rectangles are connected in a daisy chain pattern by a thin pattern extending in the Y direction. The pattern of the second detection electrode 112 is a pattern consisting of two rectangles extending in the Y direction. The pattern of the first drive electrode 211 is a pattern that combines a comb-shaped pattern and a rectangular pattern, and the pattern of the second drive electrode 212 is a pattern with a similar shape. The first separation groove 213 is a serpentine groove that passes between the comb-shaped portions of the first drive electrode 211 and the second drive electrode 212.

[0017] One end of each of the plurality of first lead-out wirings 12 is connected to the first detection electrode 111 or the second detection electrode 112. The other end of each of the plurality of first lead-out wirings 12 is electrically connected to the corresponding first extraction wiring 41 by a connection member 50. One end of each of the plurality of second lead-out wirings 22 is connected to the first drive electrode 211 or the second drive electrode 212. The other end of each of the plurality of second lead-out wirings 22 is electrically connected to the corresponding second lead-out wiring 42 by a connection member 50. Therefore, the first lead-out wiring 12 is defined as the wiring from the first detection electrode 111 or the second detection electrode 112 to the connection member 50. In other words, the first lead-out wiring 12 is defined as the wiring from the detection electrode 11 to the connection member 50. In addition, the second lead-out wiring 22 is defined as the wiring from the first drive electrode 211 or the second drive electrode 212 to the connection member 50. In other words, the second lead-out wiring 22 is defined as the wiring from the drive electrode 21 to the connection member 50. When two connecting members 50 are arranged on both sides of the pull-out film 40 as shown in FIG. 2, it is preferable that the two connecting members 50 are arranged so as to overlap each other so that sufficient pressure is applied when they are crimped together.

[0018] (3) Example of external connection using pull-out film The connection to the outside via the pull-out film 40 will be described using the case in which the shear force sensor 1 is connected to the controller 3 via the pull-out film 40 shown in Fig. 3 as an example. The controller 3 shown in Fig. 3 includes a drive circuit 3a and a sense circuit 3b. When measuring shear force, the drive circuit 3a applies AC voltages at different timings to the first drive electrode 211 and the second drive electrode 212. The sense circuit 3b measures the capacitance based on the charges detected by the first detection electrode 111 and the second detection electrode 112 at the timing when the voltage is applied to the first drive electrode 211 and the timing when the voltage is applied to the second drive electrode 212, respectively. 5, the controller 3 measures capacitances Cx1c, Cy1c, Cx2c, and Cy2c for calibration when no shear force is applied. The capacitance Cx1c is the capacitance between the first drive electrode 211 and the first detection electrode 111 measured in the calibration. The capacitance Cx2c is the capacitance between the second drive electrode 212 and the first detection electrode 111 measured in the calibration. The capacitance Cy1c is the capacitance between the first drive electrode 211 and the second detection electrode 112 measured in the calibration. The capacitance Cy2c is the capacitance between the second drive electrode 212 and the second detection electrode 112 measured in the calibration.

[0019] 6, the controller 3 measures capacitances Cx1, Cy1, Cx2, and Cy2 when a shear force is applied from, for example, a finger 90. The capacitance Cx1 is the capacitance between the first drive electrode 211 and the first detection electrode 111 when a shear force is applied. The capacitance Cx2 is the capacitance between the second drive electrode 212 and the first detection electrode 111 when a shear force is applied. The capacitance Cy1 is the capacitance between the first drive electrode 211 and the second detection electrode 112 when a shear force is applied. The capacitance Cy2 is the capacitance between the second drive electrode 212 and the second detection electrode 112 when a shear force is applied. The controller 3 calculates the magnitude of the shear force using, for example, the capacitances Cx1c, Cy1c, Cx2c, and Cy2c and the capacitances Cx1, Cy1, Cx2, and Cy2. 6, when a shear force is applied from a finger 90, for example, a positional misalignment occurs between the first base film 10 and the second base film 20. When this positional misalignment causes the first base film 10 and the second base film 20 to shift, the deformable portion 15 can be deformed with a small force because it is separated from the pressure-receiving area PA by the first slit SL1. In other words, the structure of the embodiment that electrically connects the first base film 10 and the second base film 20 to the controller 3 reduces the force that causes errors and reduced sensitivity due to the positional misalignment between the first base film 10 and the second base film 20.

[0020] (4) Relationship between deformation-permitting portion and second base film The entire deformable portion 15 shown in FIG. 7 is an unbonded region UA. The unbonded region UA ​​is an area that is not bonded to the second base film. As shown in FIG. 7, in the shear force sensor 1 of this embodiment, the deformable portion 15 is configured to overlap with the second base film 20. However, the deformable portion 15 does not overlap with the elastic sheet 30. The part of the deformable portion 15 that does not overlap with the elastic sheet 30 is a bridge portion. Therefore, as in this embodiment, the bridge portion of the deformable portion 15 overlaps with the second base film 20.

[0021] (5) Detailed configuration (5-1) First base film and second base film The films used for the first base film 10 and the second base film 20 are thin sheet-like members made of a flexible material. For example, resin films made of resin are used for the first base film 10 and the second base film 20. Examples of materials for the resin film include acrylic resin, urethane resin, fluororesin, polyester resin, polycarbonate resin, polyacetal resin, polyamide resin, olefin, and cyanoacrylate. The first base film 10 and the second base film 20 may be a composite film formed by stacking and combining at least one of different films and layers. For example, at least one of the first base film 10 and the second base film 20 may be provided with, for example, a printed layer and a shielding layer for reducing the effects of electromagnetic waves. The first base film 10 and the second base film 20 are adjusted to an appropriate thickness, for example, from 10 μm to several hundred μm. Films used to form the detection electrodes 11 and first routing wires 12, as well as the drive electrodes 21 and second routing wires 22 of the first base film 10 and the second base film 20, include metal films, conductive ceramic films, conductive paste films, and conductive polymer films. Metal films include, for example, gold, silver, copper, nickel, aluminum, titanium, and palladium films. Conductive ceramic films include, for example, indium tin oxide and zinc oxide films. Conductive paste films include thin films made of materials in which metal particles are dispersed in a resin binder. An example of a material for conductive paste films is silver paste. Conductive polymer films include, for example, polyhexylthiophene, polydioctylfluorene, pentacene, and tetrabenzoporphyrin films. To reduce costs, it is preferable to form the detection electrodes 11, the first lead-out wires 12, the drive electrodes 21 and the second lead-out wires 22 by printing using a conductive paste.

[0022] (5-2) Elastic sheet The elastic sheet 30 is made of an elastically deformable material. Examples of materials for the elastic sheet 30 include silicone, urethane, polyethylene, and polystyrene. A foam can be used for the elastic sheet 30 to increase the compressive deformation. Examples of foams include foams formed by finely dispersing gas in resin and molding them into a foamed or porous shape. The thickness of the elastic sheet 30 is appropriately selected, for example, from the range of 2 μm to 5 mm. The elastic sheet 30 may be bonded to the first base film 10 and the second base film 20 with an adhesive. Alternatively, the elastic sheet 30 itself may have adhesive properties and be bonded to the first base film 10 and the second base film 20 by itself. (5-3) Connection parts The connection member 50 may be made of, for example, an anisotropic conductive material. Examples of the anisotropic conductive material include an anisotropic conductive film (ACF) and an anisotropic conductive paste (ACP). The anisotropic conductive film (ACF) is a film in which fine conductive particles are dispersed in a film-like binder resin, and is intended to provide conductivity only in the thickness direction of the film. The anisotropic conductive paste (ACP) is a film in which fine conductive particles are dispersed in a fluid binder resin, and is intended to provide conductivity only between wirings that are pressure-bonded with the anisotropic conductive paste sandwiched therebetween. Examples of the binder resin include epoxy resin and acrylic resin. Examples of the conductive particles include particles of metal, metal alloy, metal oxide, carbon, and graphite, as well as insulating particles coated with a metal. Examples of metals used for the conductive particles include nickel, iron, copper, aluminum, tin, lead, chromium, cobalt, silver, and gold.

[0023] (5-4) Pull-out film The extraction film 40 of this embodiment is a plate-like member made of a flexible material (for example, a resin material). The extraction film 40 is, for example, a film for a flexible wiring board. For example, polyimide (PI), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyetherimide (PEI), polyphenylene sulfide (PPS), liquid crystal polymer (LCP), and unsaturated polyethylene can be used as the film for a flexible wiring board. The extraction film 40 may also be a composite of a resin and an inorganic material, and may be made of, for example, glass epoxy. The thickness of the extraction film 40 can be, for example, about several tens of μm (10 μm to 60 μm). The distance between the first base film 10 and the second base film 20 in the connecting member arrangement area CA, i.e., the total thickness of the lead-out film 40, the two connecting members 50, the first lead-out wiring 12, the second lead-out wiring 22, the first lead-out wiring 41, and the second lead-out wiring 42, is made smaller than the distance between the first base film 10 and the second base film 20 in the pressure-receiving area PA, i.e., the total thickness of the elastic sheet 30 (including the thickness of the adhesive if it is bonded with an adhesive, for example), the detection electrode 11, and the drive electrode 21. By doing so, even when a planar structure comes into contact with the shear force sensor 1, no force is applied to the connecting member arrangement area CA, and therefore damage to the members arranged in the connecting member arrangement area CA can be prevented. The first and second lead wires 41 and 42 of the lead film 40 of this embodiment are, for example, wires of a flexible wiring board. The first and second lead wires 41 and 42 are formed of a conductive material such as copper (Cu), silver (Ag), gold (Au), or aluminum (Al). The thickness of the first and second lead wires 41 and 42 is, for example, about several tens of μm (for example, about 10 μm to 30 μm). The terminal portion 43 of the lead-out film 40 is formed by, for example, molding the lead-out film 40 into a planar shape suitable for connection, or by a connector.

[0024] (6) Variations (6-1) Variation A In the above embodiment, the configuration has been described in which the deformable portion 15 overlaps the second base film 20. However, as shown in Fig. 8, the deformable portion 15 can also be configured not to overlap the second base film 20. As can be seen by comparing Fig. 7 with Fig. 8, for example, in the shear force sensor 1 according to Modification A, the second base film 20 is cut out at a portion directly facing the deformable portion 15. Therefore, there is no bridge portion in the deformable portion 15 of the shear force sensor 1 according to Modification A. (6-2) Variation B In the above embodiment, a configuration has been described in which the deformable portion 15 is not bonded to the second base film 20. However, a configuration in which a portion of the deformable portion 15 is bonded to the second base film 20 may also be used. As shown in FIG. 9 , the shear force sensor 1 according to Modification B includes a deformable portion adhesive 60 that bonds a portion of the deformable portion 15 of the bridge portion to the second base film 20. In FIG. 9 , the deformable portion adhesive 60 secures a portion of the deformable portion 15 in the bonding area AA of the second base film 20. The deformable portion adhesive 60 has viscoelasticity. Examples of the deformable portion adhesive 60 include a silicone-based adhesive, a urethane adhesive, and an epoxy-based adhesive. The viscoelastic deformable portion adhesive 60 is soft and therefore more easily tolerates deformation of the deformable portion 15 than a hard adhesive.

[0025] (6-3) Variation C In the above embodiment, a configuration has been described in which the deformable portion 15 does not overlap the elastic sheet 30. However, as in the shear force sensor 1 shown in FIG. 10 , the deformable portion 15 may also be configured to overlap the elastic sheet 30 and be bonded to the elastic sheet 30. The elastic sheet 30 is formed so as not to overlap the connecting member placement area CA. In the shear force sensor 1 configured as shown in FIG. 10 , the deformable portion 15 is fixed to the first base film 10, reducing the risk of breakage in the deformable portion 15. However, compared to the shear force sensors 1 of FIGS. 7 and 8 , the shear force sensor 1 configured as shown in FIG. 10 has a lower sensitivity due to the first base film 10 being less susceptible to deformation.

[0026] (6-4) Variation D In the above embodiment, the first slit SL1 and the deformation allowance portion 15 are formed in the first base film 10, while the second base film 20 does not have a slit or a deformation allowance portion. However, a slit may be formed in the second base film 20. In the shear force sensor 1 according to Modification D shown in FIGS. 11 and 12, not only the first slit SL1 and the deformation allowance portion 15 are formed in the first base film 10, but also the second base film 20 has a first slit SL1 and a deformation allowance portion 15 formed therein. FIG. 12 shows a cross section of the shear force sensor 1 taken along line III-III in FIG. 11. FIG. 11 shows a shear force sensor 1 configured such that a connecting member arrangement area CA is located in the center of the width direction of the first base film 10 and the second base film 20. However, the lengths of the deformation allowance portion 15 of the first base film 10 and the deformation allowance portion 15 of the second base film 20 may be different, and the connecting member arrangement area CA may be located in the center of the width direction of the first base film 10 and the second base film 20. In the shear force sensor 1 according to Modification D, the same members as those in the shear force sensor 1 according to the above embodiment are denoted by the same reference numerals, and the description thereof will be omitted here.

[0027] (6-5) Variation E In the above embodiment, a flexible wiring board film is used as the draw-out film 40. However, as shown in Figures 13 and 14, the draw-out film 40 can also be configured to double as the second base film 20. In the shear force sensor 1 shown in Figures 13 and 14, the second base film 20 and the draw-out film 40 are made of a single film. The corner CR2 formed when the second base film 20 and the draw-out film 40 are made of a single film is prone to stress concentration, so to avoid breakage due to stress, it is preferable that the corner CR2 be a gentle curve, for example, an arc (see Figure 13). Another example of the shear force sensor 1 according to Modification E is a configuration in which the deformation allowance portion 15 of the first base film 10 and the second base film 20 overlap, as shown in FIG. As yet another example of a shear force sensor 1 according to Modification E, as shown in Fig. 16, there is a configuration including a deformation-tolerant portion adhesive 60 that bonds a portion of the deformation-tolerant portion 15 of the first base film 10 to the second base film 20. In Fig. 16, the deformation-tolerant portion adhesive 60 fastens a portion of the deformation-tolerant portion 15 to the bonding area AA of the second base film 20. The deformation-tolerant portion adhesive 60 has viscoelasticity. The first base film 10 and the pull-out film 40 may be configured to consist of a single film, which also provides the same effects as when the second base film 20 and the pull-out film 40 are configured to consist of a single film.

[0028] (6-6) Variation F In the above-described modification C, the deformable portion 15 is fixed to the elastic sheet 30. However, this elastic sheet 30 also exists in the portion corresponding to the first slit SL1. However, the portion of the elastic sheet 30 corresponding to the first slit SL1 may be cut away to provide a second slit SL2, as shown in FIG. 17. The second slit SL2 formed in the elastic sheet 30 separates the pressure-receiving elastic region EA, which overlaps the pressure-receiving region PA, from the support region SA, which overlaps the deformable portion 15. The elastic sheet 30 is formed so as not to overlap the connecting member placement region CA. Compared to the shear force sensor 1 according to modification F of FIG. 17, when the first base film 10 and the second base film 20 are misaligned, the shear force sensor 1 according to modification F of FIG. 17 can reduce the force transmitted to the pressure-receiving elastic area EA via the elastic sheet 30 in the portion where the second slit SL2 was located. As described in variant E, even in a configuration in which the second base film 20 and the pull-out film 40 are made of a single film, a configuration can be added in which a second slit SL2 is formed in the elastic sheet 30, as shown in Figure 18.

[0029] (6-7) Variation G In the above embodiment and modified example, the shear force sensor 1 has been described in which the detection electrode 11 is arranged on the first base film 10 and the driving electrode 21 is arranged on the second base film 20. However, the shear force sensor of the present invention may be configured in such a way that the driving electrode 21 is arranged on the first base film 10 and the detection electrode 11 is arranged on the second base film 20. (6-8) Variation H In the above embodiment, the shear force sensor 1 has been described as detecting shear force at one location using the detection electrode 11 and the drive electrode 21. However, the shear force sensor of the present invention may be configured such that, for example, multiple pairs of the detection electrode 11 and the drive electrode 21 of the embodiment are arranged on one surface so that shear force at multiple locations can be detected.

[0030] (7) Features (7-1) In the shear force sensor 1 according to the above-described embodiment and modified example, the first base film 10 is provided with a detection electrode 11 and a first lead-out wire 12 connected to the detection electrode 11. The second base film 20 is provided with a drive electrode 21 facing the detection electrode 11 and a second lead-out wire 22 connected to the drive electrode 21. The elastic sheet 30 is disposed between the detection electrode 11 and the drive electrode 21 and is bonded to the first base film 10 and the second base film 20. The elastic sheet 30 is elastically deformed by a stress applied between the first base film 10 and the second base film 20. The lead-out film 40 is provided with a first lead-out wiring 41 corresponding to the first lead-out wiring 12, a second lead-out wiring 42 corresponding to the second lead-out wiring 22, and terminal portions 43 for electrically connecting the first lead-out wiring 41 and the second lead-out wiring 42 to the outside. The connection member 50 electrically connects the first lead-out wiring 12 and the first lead-out wiring 41 and fixes the first base film 10 to the lead-out film 40. The first base film 10 has a pressure-receiving area PA in which the detection electrodes 11 are arranged, a connection member arrangement area CA in which the connection member 50 is arranged, and a deformable portion 15 in which a part of the first lead-out wiring 12 extending from the connection member arrangement area CA to the pressure-receiving area PA is arranged. The first base film 10 has a first slit SL1 extending between the connection member arrangement area CA and the deformable portion 15 and the pressure-receiving area PA, and separating the connection member arrangement area CA and the deformable portion 15 from the pressure-receiving area PA. In the shear force sensor 1 having such a configuration, the deformable portion 15, which is separated from the pressure-receiving area PA by the first slit SL1, deforms with a smaller force than in a configuration where the deformable portion 15 is not separated. As a result, when a shear force is applied to the pressure-receiving area PA and the first base film 10 and second base film 20 shift, the reaction that prevents the shift, which occurs because the pull-out film 40, the first base film 10, and the second base film 20 are fixed, can be reduced. By reducing the reaction that prevents the shift, the shear force sensor 1 can reduce errors in shear force detection and a decrease in sensitivity.

[0031] The deformable portion 15 can be configured to be separated by the first slit SL1, so that the deformable portion 15 connects the connecting member arrangement area CA and the pressure-receiving area PA, and extends along the edge of the pressure-receiving area PA. With this configuration, the shear force sensor 1 can suppress damage to the wiring 12 arranged in the deformable portion 15 due to external force. For example, it is conceivable to use two independent pull-out films 40 for the first base film 10 and the second base film 20, and to have a structure (connection structure) that electrically connects the first base film 10 and the second base film 20 to the controller 3 to reduce the force that occurs when the first base film 10 and the second base film 20 are misaligned. However, this would increase the number of components, which would increase costs and the effort required for assembly. In this embodiment, the connection structure can be realized with a single pull-out film 40, reducing the force that causes errors and reduced sensitivity when the first base film 10 and the second base film 20 are misaligned.

[0032] (7-2) In the shear force sensors 1 according to the above-described embodiment, Modification A, Modification B, and Modification D, the deformable portion 15 is configured to include an unbonded region UA ​​that is not bonded to the second base film 20 (see FIGS. 7, 8, 9, 11, and 13). In the shear force sensor 1 configured in this manner, the unbonded region UA ​​that is not bonded to the second base film 20 is particularly susceptible to deformation within the deformable portion 15, thereby improving the effect of reducing shear force detection errors and sensitivity reductions that are caused by providing the deformable portion 15. (7-3) In the shear force sensors 1 according to the above-described embodiment and Modifications A to D, the extraction film 40 is described as being made of a flexible wiring board. In the shear force sensor 1 configured in this manner, the first extraction wiring 41 and the second extraction wiring 42 can be, for example, patterned metal wiring, making the first extraction wiring 41 and the second extraction wiring 42 less susceptible to damage.

[0033] (7-4) In the shear force sensor 1 according to Modification E, the second base film 20 and the pull-out film 40 are formed from a single film (see FIGS. 15 and 16). In the shear force sensor 1 configured in this way, by forming the second base film 20 and the pull-out film 40 from a single film, it is possible to reduce material costs, for example by eliminating the need for a flexible wiring board, and to reduce costs by reducing the labor required in the manufacturing process, for example by omitting the step of fixing the pull-out film 40 to the second base film 20. This cost reduction makes it possible to provide an inexpensive shear force sensor 1. (7-5) 7, in the shear force sensor 1 according to the above embodiment, the deformable portion 15 has a bridge portion that does not overlap the elastic sheet 30 but overlaps the second base film. In the shear force sensor 1 configured in this manner, the deformable portion 15 does not overlap the elastic sheet 30, which makes it easier for the deformable portion 15 to deform, thereby reducing shear force detection errors and sensitivity reductions. Furthermore, because the deformable portion 15 overlaps the second base film 20, the second base film 20 protects the wiring 12 leading through the deformable portion 15.

[0034] (7-6) As shown in Fig. 9, the shear force sensor 1 according to Modification B includes a deformable portion adhesive 60 that bonds a portion of the deformable portion 15 of the bridge portion to the second base film 20. This deformable portion adhesive 60 has viscoelasticity. In the shear force sensor 1 configured in this manner, a portion of the deformable portion 15 is connected to the second base film 20 by the deformable portion adhesive 60, and the movement of the deformable portion 15 is appropriately restricted by the viscoelasticity, thereby reducing the risk of damage to the wiring 12 of the deformable portion 15. (7-7) 17, the shear force sensor 1 according to Modification F is configured so that the elastic sheet 30 has a pressure-receiving elastic area EA overlapping the pressure-receiving area PA, a support area SA overlapping the deformable portion 15, and a second slit SL2 separating the pressure-receiving elastic area EA from the support area SA. In the shear force sensor 1 configured in this manner, the support area SA of the elastic sheet 30 can protect the wiring 12 of the deformable portion 15. Furthermore, the shear force sensor 1 configured in this manner can reduce the reaction that prevents the first base film 10 and the second base film 20 from shifting when a shear force is applied to the pressure-receiving area PA, which occurs because the support area SA of the elastic sheet 30 is fixed to the first base film 10 and the second base film 20, thereby reducing errors in shear force detection and reductions in sensitivity. Although one embodiment and modifications of the present invention have been described above, the present invention is not limited to the above-described embodiment and modifications, and various modifications are possible without departing from the spirit of the invention. In particular, the multiple embodiments and modifications described in this specification can be arbitrarily combined as necessary. [Explanation of symbols]

[0035] 1 Shear force sensor 3 Controller 10 First base film 11. Detection electrode 111 first detection electrode 112 second detection electrode 12 First wiring 15 Deformation tolerance section 20 Second base film 21 Drive electrode 211 First drive electrode 212 Second driving electrode 22 Second wiring 30 Elastic sheet 40 Pull-out film 41 First lead wiring 42 Second lead-out wiring 43 Terminal section 50 Connecting member 60 Adhesive for deformation-tolerant parts CA Connection material placement area EA Pressure-sensitive elastic area PA pressure receiving area SA support area SL1 First slit SL2 Second slit UA unbonded area

Claims

1. a first base film provided with a detection electrode and a first routing wiring connected to the detection electrode; a second base film provided with a driving electrode facing the detection electrode and a second routing wiring connected to the driving electrode; an elastic sheet disposed between the detection electrode and the drive electrode, bonded to the first base film and the second base film, and elastically deformed by stress applied between the first base film and the second base film; a lead-out film provided with a first lead-out wiring corresponding to the first lead-out wiring, a second lead-out wiring corresponding to the second lead-out wiring, and terminal portions for electrically connecting the first lead-out wiring and the second lead-out wiring to the outside; a connection member that electrically connects the first lead-out wiring and the first extraction wiring and fixes the first base film to the extraction film; Equipped with the first base film has a pressure-receiving region in which the detection electrodes are arranged, a connection member arrangement region in which the connection members are arranged, and a deformation-permitting portion in which a first wiring line extending from the connection member arrangement region to the pressure-receiving region is arranged, a shear force sensor, wherein the first base film has a first slit that is arranged between the connection member arrangement area and the deformation-allowing portion and the pressure-receiving area, and separates the connection member arrangement area and the deformation-allowing portion from the pressure-receiving area.

2. the deformation-permitting portion includes an unbonded region that is not bonded to the second base film, The shear force sensor of claim 1 .

3. The extraction film is a flexible wiring board. The shear force sensor according to claim 1 or 2.

4. The first base film and the pull-out film, or the second base film and the pull-out film, are each formed of a single film. The shear force sensor according to claim 1 or 2.

5. the deformable portion has a bridge portion that does not overlap the elastic sheet and overlaps the second base film; The shear force sensor according to claim 1 or 2.

6. a deformation-permitting portion adhesive that bonds a part of the deformation-permitting portion of the bridge portion to the second base film; The adhesive for the deformation-allowing portion has viscoelasticity. The shear force sensor of claim 5 .

7. The elastic sheet has a pressure-receiving elastic region overlapping the pressure-receiving region, a support region overlapping the deformation-allowing portion, and a second slit separating the pressure-receiving elastic region from the support region. The shear force sensor according to claim 1 or 2.

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