Sensor sheet

Abstract

A sensor sheet (20) is provided with: an insulator sheet (21) formed from an elastic body; a detection electrode (22) that is formed of an elastomer containing a conductive material and that is disposed on the upper surface of the insulator sheet (21); a first bypass conductor (23) disposed on the upper surface of the detection electrode (22) and extending in the longitudinal direction corresponding to the direction of the central axis (14) of the core material (15); a first lead (28) associated with the detection electrode (22); and a first wiring conductor (24) that is disposed between the first bypass conductor (23) and the first lead (28), is disposed at a distance from the first bypass conductor (23), and is electrically connected to the detection electrode (22), one end (24A) of the first wiring conductor (24) being electrically connected to the first lead (28) in a state of contact, and the other end (24B) of the first wiring conductor (24) being electrically connected to the detection electrode (22). The other end (24B) of the first wiring conductor (24) and the first bypass conductor (23) are disposed at a distance from each other with a first end gap (41) therebetween.

Description

Technical Field

[0001] The present invention relates to a sensor sheet. Background Art

[0002] As a sensor sheet mounted on a steering wheel, there is known a sensor sheet described in Patent Document 1. When the shape of the object to which the sheet-shaped sensor sheet is mounted is a three-dimensional shape (three-dimensional curved surface, including a composite plane), such as a steering wheel, the sensor sheet is required to be flexible from the viewpoint of mounting performance. In other words, the sensor sheet is required to be mounted on the mounting object while being deformed.

[0003] The technology described in Patent Document 1 describes a technology for imparting flexibility to a sensor sheet by applying an electrode sheet formed of an elastomer containing a conductive filler to the sensor sheet.

[0004] However, the elastomer containing the conductive filler becomes harder when the proportion of the conductive filler is increased, and becomes softer but has a higher resistivity when the proportion of the conductive filler is decreased.

[0005] Therefore, Patent Document 1 describes a sensor sheet including an electrode sheet formed of an elastomer containing a conductive filler, a conductive filler blending ratio that allows the desired flexibility to be exhibited, and at least one bypass conductor electrically connected to the electrode sheet.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: International Publication No. 2020 / 217855 Summary of the invention

[0009] Problems to be solved by the invention

[0010] However, in the technology described in Patent Document 1, the terminal portion connecting the sensor sheet and the external circuit is arranged on an electrode sheet formed of an elastomer containing a conductive filler. Therefore, the electrical signal (current or voltage, etc.) detected by the electrode sheet is transmitted in the order of the electrode sheet, the bypass conductor, the electrode sheet, and the terminal portion. As a result, depending on the configuration of the terminal portion in the sensor sheet, there is a possibility that the resistance value of the electrode sheet located between the bypass conductor and the terminal portion becomes larger. In this way, there is a risk of reducing the detection accuracy of the sensor sheet.

[0011] The present invention has been made in view of the above background, and provides a sensor sheet that has flexibility and can improve detection accuracy.

[0012] Means used to solve problems

[0013] One embodiment of the present invention is a sensor sheet that is wound around a winding object member of a steering wheel having a core material, wherein:

[0014] The sensor sheet comprises:

[0015] an insulator sheet formed of an elastomer;

[0016] at least one detection electrode, which is formed of an elastic body containing a conductive material, and is disposed on the upper surface of the insulator sheet to constitute at least one detection area;

[0017] A first bypass conductor, which is disposed on the upper surface of the detection electrode and extends along a length direction corresponding to the central axis direction of the core material;

[0018] A first lead wire, which corresponds to the detection electrode; and

[0019] a first wiring conductor disposed between the first bypass conductor and the first lead, disposed at a distance from the first bypass conductor and electrically connected to the detection electrode;

[0020] One end of the first wiring conductor is electrically connected to the first lead and is arranged in a state of contact with the first lead, or is arranged at a position closer to the first lead than the first bypass conductor.

[0021] The other end of the first wiring conductor is arranged at a position closer to the first bypass conductor than the one end of the first wiring conductor, and is arranged at a distance from the first bypass conductor with a first end gap therebetween.

[0022] Another aspect of the present invention is a sensor sheet that is wound around a winding object member of a steering wheel having a core material, wherein:

[0023] The sensor sheet comprises:

[0024] an insulator sheet formed of an elastomer;

[0025] at least one detection electrode, which is formed of an elastic body containing a conductive material, is disposed on the upper surface of the insulator sheet and constitutes at least one detection area; and

[0026] A first bypass conductor is disposed on the upper surface of each of the detection electrodes and extends along a length direction corresponding to the central axis direction of the core material.

[0027] The first bypass conductor is composed of a plurality of first divided bypass conductors arranged in the longitudinal direction with first bypass intermediate gaps therebetween.

[0028] Effects of the Invention

[0029] According to one embodiment of the present invention, the sensor sheet becomes easily deformed in the first end gap. As a result, the sensor sheet as a whole becomes easily deformed, so when the sensor sheet is mounted on the steering wheel, the mounting performance becomes better. In addition, compared with the case where the first wiring conductor is not provided, the resistance value between the first lead and the first bypass conductor can be reduced. As a result, the detection accuracy of the sensor sheet can be improved.

[0030] According to another embodiment of the present invention, by providing a first bypass conductor, the resistance value of the detection electrode can be reduced. Thus, the detection accuracy of the sensor sheet can be improved. In addition, in the first bypass conductor, a plurality of first split bypass conductors are arranged with the first bypass intermediate gaps spaced apart. Thus, in the first bypass intermediate gaps, the sensor sheet becomes easily deformed. As a result, the sensor sheet as a whole becomes easily deformed, so when the sensor sheet is mounted on the steering wheel, the mountability becomes better.

[0031] In addition, the reference numerals in parentheses described in the claims indicate the corresponding relationship with the specific means described in the embodiments described later, and do not limit the claims of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a front view showing a steering wheel to which the sensor sheet according to the first embodiment is mounted.

[0033] Figure 2 yes Figure 1 Sectional view along line II-II.

[0034] Figure 3 This is a plan view showing the sensor sheet according to the first embodiment.

[0035] Figure 4 This is a bottom view showing the sensor sheet according to the first embodiment.

[0036] Figure 5 yes Figure 3 VV line cross-sectional view.

[0037] Figure 6 yes Figure 3 VI-VI line cross-sectional view.

[0038] Figure 7 yes Figure 3 VII-VII line cross-sectional view.

[0039] Figure 8 It is a top view showing the sensor sheet according to the second embodiment.

[0040] Fig. 9 It is a top view showing a sensor sheet according to Embodiment 3.

[0041] Fig.10It is a top view showing a sensor sheet according to a fourth embodiment.

[0042] Fig.11 It is a top view showing a sensor sheet according to the fifth embodiment.

[0043] Fig.12 It is a top view showing a sensor sheet according to the sixth embodiment.

[0044] Fig.13 It is a top view showing a sensor sheet according to the seventh embodiment.

[0045] Fig.14 It is a top view showing a sensor sheet according to the eighth embodiment.

[0046] Fig.15 It is a top view showing a sensor sheet according to the ninth embodiment.

[0047] Fig.16 is a sensor sheet according to Embodiment 10, and Figure 3 The cross-sectional view corresponding to the line VII-VII.

[0048] Fig.17 It is a top view showing the sensor sheet according to the eleventh embodiment.

[0049] Fig.18 It is a top view showing the sensor sheet according to the twelfth embodiment.

[0050] Fig.19 is a sensor sheet according to embodiment 13, and Figure 3 The cross-sectional view corresponding to the VV line.

[0051] Fig. 20 is a sensor sheet according to embodiment 13, and Figure 3 The cross-sectional view corresponding to the VI-VI line.

[0052] Fig.21 is a sensor sheet according to embodiment 14, and Figure 3 The cross-sectional view corresponding to the VV line.

[0053] Fig. 22 is a sensor sheet according to embodiment 14, and Figure 3 The cross-sectional view corresponding to the VI-VI line.

[0054] Fig.23 It is a top view showing the sensor sheet according to the fifteenth embodiment.

[0055] Fig.24 It is a bottom view showing the sensor sheet according to the sixteenth embodiment. DETAILED DESCRIPTION

[0056] (Implementation Method 1)

[0057] 1. Configuration of the steering wheel 10

[0058] Reference Figure 1-2 Embodiment 1 will be described. This embodiment relates to a sensor sheet 20 mounted on a steering wheel 10 .

[0059] like Figure 1 As shown, the steering wheel 10 includes a core portion 11 , a ring portion 12 , and a plurality of (three in this embodiment) connecting portions 13 connecting the core portion 11 and the ring portion 12 .

[0060] The ring portion 12 is formed as a shaft member whose central axis 14 is a convex curve (circular in this embodiment). The ring portion 12 of this embodiment is formed in a circular ring shape. However, the ring portion 12 is not limited to a circular shape, and can also be formed in any shape such as an elliptical shape.

[0061] like Figure 2 As shown, the ring portion 12 includes a core material 15, a resin inner layer material 16, a sensor sheet 20, and an outer skin material 17. The core material 15 constitutes the central portion of the ring portion 12 and is formed into a shape corresponding to the shape of the ring portion 12. In this embodiment, the core material 15 is formed into a circular ring. The shape of the core material 15 can be set to any shape such as an elliptical shape corresponding to the ring portion 12. The core material 15 is formed of a conductive metal such as aluminum. The core material 15 can also be connected to a ground potential, for example. Taking the case where the axial right-angled cross-section of the core material 15 is formed into a circular shape as an example, it can be set to any shape such as a U-shape, an elliptical shape, a polygonal shape, etc. In addition, the core material 15 can also be formed of a non-conductive resin.

[0062] The resin inner layer material 16 covers the outer surface of the core material 15, the entire circumference of the annular shape of the core material 15, and the entire circumference of the circular cross-sectional shape of the core material 15. In this embodiment, the axis-right-angled cross-sectional shape of the resin inner layer material 16 is formed into a circular shape. The axis-right-angled cross-sectional shape of the resin inner layer material 16 is not limited to a circular shape, and can be set to any shape such as an oval shape, an elliptical shape, a polygonal shape, etc. The resin inner layer material 16 is formed by injection molding and is directly bonded to the surface of the core material 15. The resin inner layer material 16 is formed, for example, by a foamed resin such as foamed polyurethane. The resin inner layer material 16 can also use a non-foamed resin.

[0063] A sensor sheet 20 is wound on the outer surface of the resin inner layer material 16. The sensor sheet 20 will be described in detail later. In this embodiment, the core material 15 and the resin inner layer material 16 disposed on the outer surface of the core material 15 correspond to the winding object member. However, when a heater is wound on the outer surface of the resin inner layer material 16, the core material 15, the resin inner layer material 16 and the heater become the winding object member. In this way, the winding object member is not particularly limited.

[0064] The outer skin material 17 covers the surface of the sensor sheet 20. The outer skin material 17 can be formed by injection molding using resin or leather. The outer skin material 17 covers the outer surface of the sensor sheet 20, the entire circumference of the ring shape of the sensor sheet 20, and the entire circumference of the axial right-angled cross-section shape of the sensor sheet 20.

[0065] 2. Configuration of the sensor sheet 20

[0066] 2-1. Overall Structure of Sensor Sheet 20

[0067] Reference Figure 3 to Figure 7 , the sensor sheet 20 of this embodiment will be described. Figure 5 to Figure 7 In the figure, the thickness is exaggerated for easy explanation. In addition, although not specifically indicated, the thickness is exaggerated in other drawings.

[0068] like Figure 7 As shown in FIG. 2 , the sensor sheet 20 includes an insulator sheet 21, a detection electrode 22, a first bypass conductor 23, a first wiring conductor 24, a shield electrode 25, a second bypass conductor 26, and a second wiring conductor 27. Figure 3 as well as Figure 4 As shown, the sensor sheet 20 is connected to the processing device 30 via the first lead 28 and the second lead 29. The first lead 28 corresponds to the detection electrode 22, and the second lead 29 corresponds to the shielding electrode 25.

[0069] like Figure 3 As shown, the sensor sheet 20 is formed into a plane shape that is long in the longitudinal direction. The longitudinal direction corresponds to the direction of the central axis 14 of the core material 15. The sensor sheet 20 is flexible and is configured to be stretchable, thereby being able to be set to any shape. In other words, Figure 3 The sensor piece 20 shown is shown in an initial state before deformation.

[0070] 2-2. Insulator sheet 21

[0071] exist Figure 5 The insulating sheet 21 is shown. The insulating sheet 21 is formed of an elastomer. Therefore, the insulating sheet 21 can be elastically deformed. The insulating sheet 21 is formed of, for example, a thermoplastic elastomer. The insulating sheet 21 may be formed of the thermoplastic elastomer itself, or may be formed of an elastomer cross-linked by heating the thermoplastic elastomer as a material.

[0072] Here, the insulator sheet 21 can be selected from one or more elastomers such as styrene-based, olefin-based, vinyl chloride-based, polyurethane-based, ester-based, amide-based, etc. For example, styrene-based elastomers include SBS, SEBS, SEPS, etc. Olefin-based elastomers include copolymers of ethylene and α-olefins (ethylene-octene copolymers) in addition to EEA, EMA, EMMA, etc.

[0073] The insulator sheet 21 may contain rubber or resin other than thermoplastic elastomer. For example, when containing rubber such as ethylene-propylene rubber (EPM, EPDM), the flexibility of the insulator sheet 21 is improved. From the viewpoint of improving the flexibility of the insulator sheet 21, the insulator sheet 21 may contain a flexibility-imparting component such as a plasticizer.

[0074] 2-3. Detection electrode 22

[0075] like Figure 5 As shown, the detection electrode 22 is arranged on the upper surface of the insulator sheet 21 ( Figure 5 The detection electrode 22 forms a detection region 22A on the sensor sheet 20. Specifically, in the thickness direction of the insulator sheet 21, a region where the detection electrode 22 and the shield electrode 25 are overlapped is the detection region 22A.

[0076] like Figure 3 As shown, the detection electrode 22 is formed into a sheet-like shape that is long in the length direction. The length dimension of the detection electrode 22 in the length direction is slightly smaller than the length dimension of the insulator sheet 21 in the length direction. The length dimension of the detection electrode 22 in the cross direction is slightly smaller than the length dimension of the insulator sheet 21 in the cross direction. In addition, the cross direction refers to a direction that intersects with the length direction and refers to a direction along the upper surface of the insulator sheet 21. The detection electrode 22 of this embodiment is buried in the upper surface of the insulator sheet 21 in a state where the upper surface of the detection electrode 22 is exposed. However, the detection electrode 22 can also be stacked on the upper surface of the insulator sheet 21.

[0077] The detection electrode 22 has conductivity, flexibility, and stretchability in the surface direction. The detection electrode 22 is formed of a conductive elastic body. In other words, the detection electrode 22 is formed of an elastic body containing a conductive filler.

[0078] The elastomer used for the detection electrode 22 is preferably formed of the same material as the main component of the insulator sheet 21. That is, the detection electrode 22 can be selected from one or more elastomers such as styrene, olefin, vinyl chloride, polyurethane, ester, and amide. For example, as styrene elastomers, SBS, SEBS, SEPS, etc. can be listed. As olefin elastomers, in addition to EEA, EMA, EMMA, etc., copolymers of ethylene and α-olefins (ethylene-octene copolymers) can be listed.

[0079] However, the detection electrode 22 is selected to have a higher softening point than the insulating sheet 21. This is to allow the insulating sheet 21 to soften before the detection electrode 22 when the detection electrode 22 is fixed to the insulating sheet 21 by welding (for example, heat welding) the insulating sheet 21 itself.

[0080] The detection electrode 22 is fixed to the insulator sheet 21 by welding (for example, heat welding) the insulator sheet 21 itself. Furthermore, the detection electrode 22 is fixed to the insulator sheet 21 by welding (for example, heat welding) the detection electrode 22 itself. In other words, the detection electrode 22 and the insulator sheet 21 are fixed by mutual welding.

[0081] like Figure 3 As shown, in this embodiment, one detection electrode 22 is arranged on one insulator sheet 21. However, a configuration in which a plurality of detection electrodes 22 are arranged on one insulator sheet 21 is also possible. The plurality of detection electrodes 22 may be arranged on the upper surface of the insulator sheet 21 in the longitudinal direction or in the cross direction.

[0082] 2-4. First bypass conductor 23

[0083] like Figure 5 As shown in the figure, the first bypass conductor 23 is arranged on the upper surface of the detection electrode 22. The first bypass conductor 23 includes a plurality of first divided bypass conductors 23A. Each of the first divided bypass conductors 23A constituting the first bypass conductor 23 is buried in the upper surface of the detection electrode 22 in a state where the upper surface of each of the first divided bypass conductors 23A is exposed. However, each of the first divided bypass conductors 23A may also be stacked on the upper surface of the detection electrode 22.

[0084] like Figure 3 As shown, the first bypass conductor 23 extends in the length direction. The first bypass conductor 23 of this embodiment is composed of a plurality of (three in this embodiment) first split bypass conductors 23A. The plurality of first split bypass conductors 23A are arranged in parallel in the length direction with a first bypass intermediate gap 40 spaced apart. However, the first bypass conductor 23 may also be composed of a plurality of first split bypass conductors 23A without the first split bypass conductor 23A, or may be composed of two or more first split bypass conductors 23A.

[0085] The length dimension of each first division bypass conductor 23A in the intersecting direction is smaller than the length dimension of the detection electrode 22 in the intersecting direction. In this embodiment, each first division bypass conductor 23A is arranged near the center position of the detection electrode 22 in the intersecting direction.

[0086] The first bypass conductor 23 extends from one end portion ( Figure 3 right end) across to the other end ( Figure 3 In other words, the plurality of first split bypass conductors 23A span from one end of the detection electrode 22 to the other end, and are arranged in parallel with the first bypass intermediate gaps 40. In this embodiment, the gap size of each first bypass intermediate gap 40 is set to be the same in the length direction. However, the gap size of each first bypass intermediate gap 40 may also be different.

[0087] Each first divided bypass conductor 23A constituting the first bypass conductor 23 has a resistivity lower than the resistivity of the detection electrode 22. In particular, it is effective when the resistivity of each first divided bypass conductor 23A is set to be less than one tenth of the resistivity of the detection electrode 22. Each first divided bypass conductor 23A is electrically connected to the detection electrode 22 at a portion in contact with the detection electrode 22.

[0088] The material forming each of the first divided bypass conductors 23A constituting the first bypass conductor 23 is not particularly limited, and the following materials can be exemplified.

[0089] (1) Metal wire

[0090] The first split bypass conductor 23A may be formed of a metal wire. The metal wire is, for example, a copper wire, a nickel-chromium alloy wire, etc. In this case, the resistivity of the first split bypass conductor 23A can be set to less than one tenth of the resistivity of the detection electrode 22, and further set to less than one hundredth. The first split bypass conductor 23A is fixed to the detection electrode 22 by welding (for example, thermal welding) the detection electrode 22 itself.

[0091] (2) Conductive fibers

[0092] The first split bypass conductor 23A can be formed by conductive fibers. The conductive fibers are formed by covering the surface of flexible fibers with a conductive material. As conductive fibers, for example, copper, nickel, etc. are plated on the surface of resin fibers such as polyethylene. The first split bypass conductor 23A can also be formed by a conductive cloth (woven fabric or non-woven fabric) formed using conductive fibers. The resistivity of the first split bypass conductor 23A can be set to less than one tenth of the resistivity of the detection electrode 22, and further set to less than one hundredth. The first split bypass conductor 23A is fixed to the detection electrode 22 by welding (for example, heat welding) of the detection electrode 22 itself.

[0093] Since the first division bypass conductor 23A is formed of conductive fibers, the detection electrode 22 softens and enters the space between the conductive fibers, thereby making the first division bypass conductor 23A and the detection electrode 22 more firmly bonded.

[0094] Furthermore, it is preferred that the first split bypass conductor 23A is formed as a conductive cloth having a mesh and formed in a sheet shape, and the orientation direction of the mesh is tilted relative to the length direction of the detection electrode 22. Thus, the first split bypass conductor 23A can be extended along the length direction of the detection electrode 22. That is, when the detection electrode 22 is extended along the length direction, the first split bypass conductor 23A follows the extension deformation of the detection electrode 22. As a result, the elongation performance of the sensor sheet 20 is improved. In particular, it is preferred that the orientation direction of the mesh of the first split bypass conductor 23A is tilted 45° relative to the length direction of the detection electrode 22. Thus, the elongation performance of the sensor sheet 20 in the length direction and the elongation performance in the short side direction are improved.

[0095] (3) Conductive elastomer

[0096] The first split bypass conductor 23A may be formed of a conductive elastomer. That is, the first split bypass conductor 23A may be formed of an elastomer containing a conductive filler. However, the resistivity of each first split bypass conductor 23A constituting the first bypass conductor 23 is smaller than that of the detection electrode 22. Therefore, in the case of applying the same kind of conductive filler, the proportion of the conductive filler applied to the first split bypass conductor 23A becomes higher. Preferably, the elastomer applied to the first split bypass conductor 23A is the same kind of elastomer as the detection electrode 22.

[0097] By forming the first division bypass conductor 23A as an elastic body, the flexibility of the entire sensor sheet 20 is increased. Furthermore, by making the elastic body of the first division bypass conductor 23A the same as that of the detection electrode 22, the fixing performance of the two is further improved.

[0098] 2-5. First wiring conductor 24

[0099] like Figure 3 As shown, at one end of the detection electrode 22 in the length direction ( Figure 3 The first wiring conductor 24 is arranged at the right end of the detection electrode 22. The first wiring conductor 24 is arranged on the upper surface of the detection electrode 22. The first wiring conductor 24 is buried in the upper surface of the detection electrode 22 in a state where the upper surface of the first wiring conductor 24 is exposed. However, the first wiring conductor 24 may also be stacked on the upper surface of the detection electrode 22.

[0100] The first wiring conductor 24 extends in a straight line in the intersecting direction. However, the first wiring conductor 24 may extend in a curved line in the intersecting direction, or may extend in a curved manner in the intersecting direction.

[0101] One end 24A of the first wiring conductor 24 is arranged at a side edge intersecting the crossing direction among the side edges of the detection electrode 22. The other end 24B of the first wiring conductor 24 is arranged near the center position of the detection electrode 22 in the crossing direction. The other end 24B of the first wiring conductor 24 is arranged at a position closer to the first bypass conductor 23 than the one end 24A of the first wiring conductor 24.

[0102] The first wiring conductor 24 is arranged at a distance from the first bypass conductor 23. In this embodiment, the other end 24B of the first wiring conductor 24 is arranged at a distance in the longitudinal direction relative to the one end 23B in the longitudinal direction of the first divided bypass conductor 23A constituting the first bypass conductor 23. The gap between the first divided bypass conductor 23A and the first wiring conductor 24 is a first end gap 41.

[0103] The first wiring conductor 24 has a resistivity lower than that of the detection electrode 22. In particular, it is effective to set the resistivity of the first wiring conductor 24 to be less than one tenth of the resistivity of the detection electrode 22. The first wiring conductor 24 is electrically connected to the detection electrode 22 at a portion in contact with the detection electrode 22.

[0104] The first wiring conductor 24 can be formed of the same material as that constituting the first bypass conductor 23 , and therefore, duplicate descriptions are omitted.

[0105] like Figure 6 As shown in the figure, one end 24A of the first wiring conductor 24 is formed as a non-contact region 24C that does not contact the upper surface of the insulator sheet 21 and the detection electrode 22. On the upper surface of the insulator sheet 21 and the detection electrode 22, a first bonding restriction layer 31 is arranged at a position corresponding to the non-contact region 24C of the first wiring conductor 24. The first bonding restriction layer 31 is made of an insulating synthetic resin and is formed in a sheet shape. The first bonding restriction layer 31 is configured so that the non-contact region 24C of the first wiring conductor 24 does not directly contact the upper surface of the insulator sheet 21 and the detection electrode 22.

[0106] The first joint restricting layer 31 is joined to the insulator sheet 21 by welding (e.g., heat welding) of the insulator sheet 21 itself. The first joint restricting layer 31 is formed of, for example, a material having a higher softening point than the insulator sheet 21. For example, the first joint restricting layer 31 may be a resin sheet formed of a thermoplastic material.

[0107] The end of the first lead 28 is arranged between the first joint restricting layer 31 and the non-contact region 24C of the first wiring conductor 24 .

[0108] One end 24A of the first wiring conductor 24 is connected to the first lead 28. The first lead 28 includes a core wire 51 and a cover 52 that insulates and covers the outer peripheral surface of the core wire 51. The core wire 51 is formed of a conductive metal such as copper, copper alloy, aluminum, or aluminum alloy. The cover 52 is formed of a thermoplastic material. The cover 52 may be a thermoplastic material having insulating properties, and may be formed of a material that can be applied to the above-mentioned insulator sheet 21, for example.

[0109] The first lead wire 28 includes a core wire exposed portion 53 at the front end portion of the first lead wire 28 , where the core wire 51 is exposed by stripping the covering portion 52 .

[0110] The core wire exposed portion 53 may be configured as follows, for example. In the core wire exposed portion 53, a metal plating layer is formed on the core wire 51 formed of a metal wire. In this case, the metal plating layer is preferably nickel-plated. In addition, in the core wire exposed portion 53, a fluid welding layer may be formed on the core wire 51. The metal plating layer and the fluid welding layer play a role in improving the conduction with the first wiring conductor 24.

[0111] The exposed core portion 53 of the first lead 28 is arranged on the inner side in the intersecting direction in the non-contact region 24C of the first wiring conductor 24. The first lead 28 extends from the edge of the first wiring conductor 24 away from the sensor sheet 20 in the intersecting direction.

[0112] The non-contact area 24C of the first wiring conductor 24 is electrically connected to the core wire 51 in the core wire exposed portion 53, for example, via a metal plating layer or a fluid welding layer. Specifically, after the first lead 28 is inserted between the first wiring conductor 24 and the first bonding restriction layer 31, the non-contact area 24C of the first wiring conductor 24 is subjected to ultrasonic welding treatment, thereby electrically connecting the first wiring conductor 24 to the core wire exposed portion 53 of the first lead 28. In addition, the first wiring conductor 24 and the core wire exposed portion 53 of the first lead 28 have metal on the surface, so they are joined by ultrasonic welding. On the other hand, the core wire exposed portion 53 of the first lead 28 is adjacent to the first bonding restriction layer 31, and since it is metal and resin, it is not welded even if ultrasonic welding is performed.

[0113] 2-6. Shielding electrode 25

[0114] like Figure 5 As shown, the shielding electrode 25 is stacked on the lower surface of the insulator sheet 21 ( Figure 5 The shield electrode 25 is located on the lower surface of the steering wheel 10, that is, on the opposite side of the detection electrode 22 in the insulator sheet 21. That is, the shield electrode 25 is arranged between the insulator sheet 21 and the resin inner layer material 16 of the steering wheel 10.

[0115] like Figure 4As shown, the shielding electrode 25 is formed into a sheet shape that is long in the length direction. The length dimension of the shielding electrode 25 in the length direction is slightly smaller than the length dimension of the insulator sheet 21 in the length direction. The length dimension of the shielding electrode 25 in the cross direction is slightly smaller than the length dimension of the insulator sheet 21 in the cross direction. Figure 5 As shown in FIG. 1 , the shield electrode 25 of this embodiment is buried in the lower surface of the insulator sheet 21 in a state where the lower surface of the shield electrode 25 is exposed. However, the shield electrode 25 may be stacked on the lower surface of the insulator sheet 21 .

[0116] The shield electrode 25 is arranged at a position overlapping with the detection electrode 22 in the thickness direction of the insulator sheet 21. The shield electrode 25 of this embodiment has the same shape and size as the detection electrode 22. However, the shield electrode 25 may be larger than the detection electrode 22.

[0117] The shielding electrode 25 of this embodiment has conductivity, and has flexibility and stretchability in the surface direction. The shielding electrode 25 is formed of a conductive elastomer. That is, the shielding electrode 25 is formed of an elastomer containing a conductive filler. The conductive elastomer used for the shielding electrode 25 is the same as the conductive elastomer used for the detection electrode 22, so repeated descriptions are omitted. However, the shielding electrode 25 can also be formed of a conductive cloth formed using conductive fibers.

[0118] 2-7. Second bypass conductor 26

[0119] like Figure 4 As shown in FIG. 1 , a second bypass conductor 26 is arranged on the lower surface of the shield electrode 25. The second bypass conductor 26 includes a plurality of second divided bypass conductors 26A. Each second divided bypass conductor 26A constituting the second bypass conductor 26 is buried in the lower surface of the shield electrode 25 in a state where the lower surface of each second divided bypass conductor 26A is exposed. However, each second divided bypass conductor 26A may be stacked on the lower surface of the shield electrode 25.

[0120] like Figure 4 As shown, the second bypass conductor 26 extends in the length direction. The second bypass conductor 26 of this embodiment is composed of a plurality of (three in this embodiment) second split bypass conductors 26A arranged in parallel along the length direction with a second bypass intermediate gap 42 spaced apart. However, the second bypass conductor 26 may be composed of no second split bypass conductor 26A, or may be composed of two or more second split bypass conductors 26A.

[0121] The length dimension of each second divided bypass conductor 26A in the intersecting direction is smaller than the length dimension of the shield electrode 25 in the intersecting direction. In this embodiment, each second divided bypass conductor 26A is arranged near the center position of the shield electrode 25 in the intersecting direction.

[0122] The second bypass conductor 26 extends from one end portion ( Figure 4 right end) across to the other end ( Figure 4 In other words, the plurality of second split bypass conductors 26A span from one end of the shielding electrode 25 to the other end, and are arranged in parallel with the second bypass intermediate gaps 42. In this embodiment, the gap size of each second bypass intermediate gap 42 is set to be the same in the length direction. However, the gap size of each second bypass intermediate gap 42 may also be different.

[0123] Each second divided bypass conductor 26A constituting the second bypass conductor 26 has a resistivity lower than that of the shield electrode 25. In particular, it is effective when the resistivity of each second divided bypass conductor 26A is set to be less than one tenth of the resistivity of the shield electrode 25. Each second divided bypass conductor 26A is electrically connected to the shield electrode 25 at a portion in contact with the shield electrode 25.

[0124] The second bypass conductor 26 is formed of the same material as the first bypass conductor 23 , and therefore duplicate descriptions are omitted.

[0125] 2-8. Second wiring conductor 27

[0126] like Figure 4 As shown, at one end portion of the shield electrode 25 in the length direction ( Figure 4 The second wiring conductor 27 is arranged at the left end portion of the shield electrode 25. The second wiring conductor 27 is arranged on the lower surface of the shield electrode 25. The second wiring conductor 27 is buried in the lower surface of the shield electrode 25 in a state where the lower surface of the second wiring conductor 27 is exposed. However, the second wiring conductor 27 may be stacked on the lower surface of the shield electrode 25.

[0127] The second wiring conductor 27 extends in a straight line along the intersecting direction. However, the second wiring conductor 27 may extend in a curved line along the intersecting direction, or may extend in a curved manner along the intersecting direction.

[0128] One end 27A of the second wiring conductor 27 is disposed at a side edge intersecting the intersecting direction among the side edges of the shield electrode 25. The other end 27B of the second wiring conductor 27 is disposed near the center position of the shield electrode 25 in the intersecting direction.

[0129] The second wiring conductor 27 is arranged at a distance from the second bypass conductor 26. In this embodiment, the other end 27B of the second wiring conductor 27 is arranged at a distance in the longitudinal direction relative to the one end 26B in the longitudinal direction of the second divided bypass conductor 26A constituting the second bypass conductor 26. The gap between the second divided bypass conductor 26A and the second wiring conductor 27 is a second end gap 43.

[0130] The second wiring conductor 27 has a resistivity lower than that of the shield electrode 25. In particular, it is effective when the resistivity of the second wiring conductor 27 is set to one tenth or less of the resistivity of the shield electrode 25. The second wiring conductor 27 is electrically connected to the shield electrode 25 at a portion in contact with the shield electrode 25.

[0131] The second wiring conductor 27 can be formed of the same material as that constituting the first bypass conductor 23 , and therefore, duplicate descriptions thereof will be omitted.

[0132] like Figure 6 As shown in FIG. 1 , one end 27A of the second wiring conductor 27 is formed as a non-contact region 27C that does not contact the lower surface of the insulator sheet 21 and the shield electrode 25. A second joint restriction layer 32 is disposed at a position corresponding to the non-contact region 27C of the second wiring conductor 27 on the lower surface of the insulator sheet 21 and the shield electrode 25. The second joint restriction layer 32 is made of an insulating synthetic resin and is formed in a sheet shape. The non-contact region 27C of the second wiring conductor 27 is not in direct contact with the lower surface of the insulator sheet 21 and the shield electrode 25 by the second joint restriction layer 32.

[0133] The second joint restricting layer 32 is joined to the insulator sheet 21 by welding (e.g., heat welding) of the insulator sheet 21 itself. The second joint restricting layer 32 is formed of, for example, a material having a higher softening point than the insulator sheet 21. For example, the second joint restricting layer 32 can be a resin sheet formed of a thermoplastic material.

[0134] An end portion of the second lead 29 is arranged between the second joining restricting layer 32 and the non-contact region 27C of the second wiring conductor 27 .

[0135] The other end of the second wiring conductor 27 is connected to the second lead 29. Since the second lead 29 has the same configuration as the first lead 28, the same reference numerals are given to the same components and duplicate descriptions are omitted.

[0136] 2-9. Configuration of Bypass Conductors 23, 26, Wiring Conductors 24, 27, and Gaps 40, 41, 42, 43

[0137] like Figure 3 As shown, in this embodiment, the interval of the first bypass intermediate gap 40 is larger than the interval of the first end gap 41 in the longitudinal direction.

[0138] like Figure 7As shown, the first bypass conductor 23 and the second bypass conductor 26 are arranged at positions overlapping in the thickness direction of the insulator sheet 21. Specifically, each first divided bypass conductor 23A and each second divided bypass conductor 26A are arranged at positions overlapping in the thickness direction of the insulator sheet 21. In addition, each first bypass intermediate gap 40 and each second bypass intermediate gap 42 are arranged at positions overlapping in the thickness direction of the insulator sheet 21.

[0139] like Figure 7 As shown, the first wiring conductor 24 and the second wiring conductor 27 are arranged at overlapping positions in the thickness direction of the insulator sheet 21. In addition, the first end gap 41 and the second end gap 43 are arranged at overlapping positions in the thickness direction of the insulator sheet 21.

[0140] The first bypass middle gap 40 and the first end gap 41 are smaller than the minimum width dimension of the detection object (not shown). As a result, the detection object is in contact with at least the first bypass conductor 23 or the first wiring conductor 24, so it is possible to detect whether the detection object is in contact with the steering wheel 10. In this method, the contact or non-contact of a hand (palm, back of hand, or finger) as an example of the detection object relative to the steering wheel 10 is detected. Among the hands as the detection object, the smallest detection object is a finger, wherein the front end portion of the finger is the smallest detection object. The first bypass middle gap 40, the second bypass middle gap 42, the first end gap 41, and the second end gap 43 are set to be smaller than the minimum width dimension of at least the front end portion of the finger.

[0141] 2-10. Processing device 30

[0142] The processing device 30 is electrically connected to the sensor sheet 20 via the first lead 28 and the second lead 29. The processing device 30 acquires a voltage or a current from the sensor sheet 20, and performs detection calculation of the target action based on the acquired voltage or current.

[0143] 3. Effects of this method

[0144] Next, the effect of this method is described. The detection electrode 22 is formed of an elastic body containing a conductive filler, and therefore has a greater resistivity than a metal sheet or a conductive cloth. However, the sensor sheet 20 has a first wiring conductor 24. Thus, the resistance value of the sensor sheet 20 can be reduced, and thus the detection accuracy of the sensor sheet 20 can be improved.

[0145] One end 24A of the first wiring conductor 24 is electrically connected to the first lead 28 and is arranged in contact with the first lead 28. In addition, the other end 24B of the first wiring conductor 24 is arranged at a distance from the first bypass conductor 23 with the first end gap 41 therebetween. Thus, the sensor sheet 20 is easily deformed in the first end gap 41. As a result, the entire sensor sheet 20 is easily deformed, so when the sensor sheet 20 is mounted on the steering wheel 10, the mounting performance is improved.

[0146] In addition, the resistance value between the first lead 28 and the first bypass conductor 23 can be reduced compared to the case where the first wiring conductor 24 is not provided. This can improve the detection accuracy of the sensor sheet 20.

[0147] In addition, according to this embodiment, in the first bypass conductor 23, the plurality of first divided bypass conductors 23A are arranged with the first bypass intermediate gap 40 spaced apart. Thus, the sensor sheet 20 becomes easy to deform in the first bypass intermediate gap 40. As a result, the sensor sheet 20 as a whole becomes easy to deform, so when the sensor sheet 20 is mounted on the steering wheel 10, the mounting performance becomes further improved.

[0148] According to this embodiment, each first bypass intermediate gap 40 and each second bypass intermediate gap 42 are arranged at a position overlapping in the thickness direction of the insulator sheet 21. In addition, the first end gap 41 and the second end gap 43 are arranged at a position overlapping in the thickness direction of the insulator sheet 21. As a result, the sensor sheet 20 becomes easy to deform, so when the sensor sheet 20 is mounted on the steering wheel 10, the mounting performance becomes good.

[0149] In this embodiment, the gap size of the first bypass middle gap 40 is set larger than the gap size of the first end gap 41 in the longitudinal direction. The above embodiment is effective when flexibility is required in the region where the first bypass conductor 23 is arranged in the sensor sheet 20.

[0150] (Implementation Method 2)

[0151] Reference Figure 8 , Embodiment 2 is described. In addition, in the reference numerals used in Embodiment 2 and thereafter, unless otherwise indicated, the same reference numerals as those used in the already existing embodiments represent the same constituent elements as those in the already existing embodiments.

[0152] In this embodiment, the gap size of the first bypass intermediate gap 40 is smaller than the gap size of the first end gap 41 in the longitudinal direction. Therefore, this embodiment is effective when flexibility is required in the region where the first wiring conductor 24 and the first lead 28 are arranged in the sensor sheet 20.

[0153] (Implementation 3)

[0154] Reference Fig. 9 Embodiment 3 will be described. In this embodiment, the first bypass conductor 23 includes two first divided bypass conductors 23A arranged in parallel in the longitudinal direction. However, the number of the first divided bypass conductors 23A may be arbitrary.

[0155] The first wiring conductor 24 of this embodiment is electrically connected to the first lead 28, and includes a first extension portion 61 extending in the cross direction, and a second extension portion 62 extending in the length direction by bending from the end portion on the opposite side to the first lead 28 toward the direction close to the first bypass conductor 23. The length dimension of the first extension portion 61 in the cross direction is formed to be shorter than the length dimension of the second extension portion 62 in the length direction. The end portion of the second extension portion 62 on the opposite side to the first extension portion 61 is the other end 24B of the first wiring conductor 24. A first end gap 41 is formed between the other end 24B of the first wiring conductor 24 and the one end 23B of the first divided bypass conductor 23A.

[0156] According to this embodiment, the first wiring conductor 24 has the second extension portion 62 extending in the direction approaching the first bypass conductor 23, so that the resistance value of the sensor sheet 20 can be reduced. This embodiment is effective when the area where the first bypass conductor 23 and the first wiring conductor 24 are arranged in the sensor sheet 20 does not require much flexibility.

[0157] (Implementation 4)

[0158] Reference Fig.10 , Embodiment 4 is described. In this embodiment, the first bypass conductor 23 is composed of three first split bypass conductors 23A. Among the three first split bypass conductors 23A, Fig.10 The first division bypass conductor 23A at the right end is formed to be shorter in length in the longitudinal direction than the other two first division bypass conductors 23A. However, the number of first division bypass conductors 23A is arbitrary.

[0159] The first wiring conductor 24 of this embodiment is electrically connected to the first lead 28, and includes a first extension portion 61 extending in the cross direction, and a second extension portion 62 extending in the length direction by bending from the end on the side opposite to the first lead 28 toward the direction close to the first bypass conductor 23. The length dimension of the first extension portion 61 in the cross direction is formed to be longer than the length dimension of the second extension portion 62 in the length direction. In the second extension portion 62, the end on the side opposite to the first extension portion 61 is the other end 24B of the first wiring conductor 24. Fig.10 A first end gap 41 is formed between one end 23B of the first split bypass conductor 23A at the right end of the first split bypass conductor 23A.

[0160] In this embodiment, the gap size of the first bypass intermediate gap 40 is set larger than the gap size of the first end gap 41 in the longitudinal direction.

[0161] Providing the second extension portion 62 can reduce the resistance value of the sensor sheet 20. In addition, the gap size of the first bypass intermediate gap 40 is set larger than the gap size of the first end gap 41 in the longitudinal direction, thereby improving the flexibility of the sensor sheet 20 in the longitudinal direction.

[0162] (Implementation 5)

[0163] Reference Fig.11 Embodiment 5 will be described. In this embodiment, the first wiring conductor 24 is arranged at a distance in the intersecting direction relative to one end in the longitudinal direction of the first bypass conductor 23. The first wiring conductor 24 is electrically connected to the first lead 28 extending in the intersecting direction.

[0164] In this embodiment, among the plurality of (in this embodiment) first divided bypass conductors 23A constituting the first bypass conductor 23, the first divided bypass conductor 23A is located at Fig.11 One end 23B of the first split bypass conductor 23A at the right end ( Fig.11 A first end gap 41 is formed between the right end of the first wiring conductor 24 and the other end 24B of the first wiring conductor 24.

[0165] According to this embodiment, the first bypass conductor 23 and the first wiring conductor 24 are arranged at a distance in the intersecting direction, and therefore, this is effective when flexibility in the intersecting direction is required for the sensor sheet 20 .

[0166] (Implementation method 6)

[0167] Reference Fig.12 , Embodiment 6 is described. In this embodiment, the first wiring conductor 24 extends in the longitudinal direction. One end 24A of the first wiring conductor 24 is arranged at one end ( Fig.12 ), and is electrically connected to the first lead 28.

[0168] This aspect is effective when it is required to lead out the first lead wire 28 from the end portion in the longitudinal direction of the sensor sheet 20 .

[0169] (Implementation 7)

[0170] Reference Fig.13 , Embodiment 7 is described. In the detection electrode 22 of this embodiment, one end in the length direction ( Fig.13 The right end of the insulating sheet 21 is larger than one end of the insulating sheet 21 ( Fig.13 The right end of the Fig.13Thus, an exposed region 21A is formed in which the upper surface of the insulator sheet 21 is exposed from the detection electrode 22. The second extension portion 62 of the first wiring conductor 24 is arranged across the detection region 22A and the exposed region 21A. The first extension portion 61 of the first wiring conductor 24 is arranged in the exposed region 21A.

[0171] In this embodiment, the first bypass conductor 23 is composed of two first split bypass conductors 23A. In this embodiment, the first split bypass conductor 23 is located at Fig.13 A first end gap 41 is formed between one end 23B of the first split bypass conductor 23A at the right end and the other end 24B of the first wiring conductor 24. In this embodiment, the gap size of the first bypass intermediate gap 40 and the gap size of the first end gap 41 are set to be the same in the length direction.

[0172] The configuration other than that described above is substantially the same as that of the third embodiment, and thus the same components are denoted by the same reference numerals and duplicate descriptions are omitted.

[0173] (Implementation 8)

[0174] Reference Fig.14 , Embodiment 8 is described. In the detection electrode 22 of this embodiment, one end in the length direction ( Fig.14 The right end of the insulating sheet 21 is larger than one end of the insulating sheet 21 ( Fig.14 The right end of the Fig.14 Thus, an exposed region 21A is formed in which the upper surface of the insulator sheet 21 is exposed from the detection electrode 22. The second extension portion 62 of the first wiring conductor 24 is arranged across the detection region 22A and the exposed region 21A. The first extension portion 61 of the first wiring conductor 24 is arranged in the exposed region 21A.

[0175] In this embodiment, the first bypass conductor 23 is composed of three first split bypass conductors 23A. In this embodiment, the first split bypass conductor 23 is located at Fig.14 A first end gap 41 is formed between one end 23B of the first split bypass conductor 23A at the right end and the other end 24B of the first wiring conductor 24. In this embodiment, the gap size of the first bypass intermediate gap 40 is larger than the gap size of the first end gap 41 in the longitudinal direction.

[0176] The configuration other than that described above is substantially the same as that of the fourth embodiment, and thus the same components are denoted by the same reference numerals and duplicate descriptions are omitted.

[0177] (Implementation method 9)

[0178] Reference Fig.15, Embodiment 9 is described. The sensor sheet 20 of this embodiment has a pair of outer edges extending in the length direction, and has a cutout portion 33 that opens outward in the cross direction. A plurality of (three in this embodiment) cutout portions 33 are formed on each outer edge. The cutout portions 33 formed on each outer edge are formed at positions that overlap in the cross direction. However, the number of cutout portions 33 formed on each outer edge is arbitrary, and may be one to two, or four or more.

[0179] The first bypass intermediate gap 40 is formed at a position corresponding to the cutout portion 33. Specifically, in the intersecting direction, the cutout portion 33 and the first bypass intermediate gap 40 are formed at an overlapping position.

[0180] In addition, the width dimension of the cutout portion 33 in the longitudinal direction is set to be larger than the gap dimension of the first bypass intermediate gap 40 .

[0181] According to this embodiment, the sensor sheet 20 becomes easy to be wound around the steering wheel 10 by providing the cutout portion 33. In particular, the length dimension of the sensor sheet 20 in the cross direction becomes small in the portion provided with the cutout portion 33, so that the sensor sheet 20 becomes easy to deform. The first bypass intermediate gap 40 is arranged at a position corresponding to the cutout portion 33, so that the sensor sheet 20 becomes even easier to deform. As a result, the sensor sheet 20 is further easy to attach to the steering wheel 10.

[0182] In addition, the position of the cutout portion 33 formed in each outer edge is not particularly limited, and may be formed at a position different from the position overlapping in the intersecting direction.

[0183] In the present embodiment, the cutouts 33 are formed on both sides of a pair of outer edges. However, the present invention is not limited thereto and the cutouts 33 may be formed on one outer edge and not formed on the other outer edge.

[0184] (Implementation 10)

[0185] Reference Fig.16 Embodiment 10 will be described. According to this embodiment, the second bypass conductor 26 is arranged to extend from one end to the other end of the insulator sheet 21 in the longitudinal direction. In other words, the second bypass conductor 26 of this embodiment is not divided into second divided bypass conductors 26A.

[0186] (Implementation 11)

[0187] Reference Fig.17 , Embodiment 11 is described. In this embodiment, one end portion ( Fig.17 The right end of the detection electrode 22 is located at a position slightly larger than one end of the detection electrode 22 in the length direction ( Fig.17 The right end of the length direction is closer to the inside ( Fig.17 Thus, an electrical connection region 22B where the detection electrode 22 and the shielding electrode 25 do not overlap is formed in the thickness direction of the insulator sheet 21. In the electrical connection region 22B, the first divided bypass conductor 23A constituting the first bypass conductor 23 and the first wiring conductor 24 are electrically connected via the detection electrode 22.

[0188] As described above, the region where the detection electrode 22 and the shield electrode 25 overlap in the thickness direction of the insulator sheet 21 is the detection region 22A. The detection region 22A and the electrical connection region 22B are divided into different regions in the detection electrode 22 .

[0189] The first divided bypass conductor 23A constituting the first bypass conductor 23 is arranged so as to straddle the detection region 22A and the electrical connection region 22B. In addition, the first wiring conductor 24 is arranged in the electrical connection region 22B.

[0190] In the electrical connection region 22B, the detection electrode 22 and the shield electrode 25 do not overlap in the thickness direction, so the flexibility of the sensor sheet 20 is improved. In other words, the flexibility of the region where the first lead 28 and the first wiring conductor 24 are arranged is improved, so the sensor sheet 20 can be mounted on the steering wheel 10 more easily.

[0191] In this embodiment, the position where the first lead 28 is led out from the sensor sheet 20 and the position where the second lead 29 is led out from the sensor sheet 20 are offset in the length direction. This can reduce the thickness of the sensor sheet 20.

[0192] (Implementation 12)

[0193] Reference Fig.18 Embodiment 12 is described. One end 24A of the first wiring conductor 24 of this embodiment is arranged at a distance from the first lead 28. On the other hand, the other end 24B of the first wiring conductor 24 is arranged at a distance from one end 23B of the first bypass conductor 23 with a first end gap 41 therebetween. One end 24A of the first wiring conductor 24 is arranged at a position closer to the first lead 28 than the first bypass conductor 23. The first lead 28, the first wiring conductor 24, and the first bypass conductor 23 are electrically connected via the detection electrode 22.

[0194] According to this embodiment, the first lead wire 28 and the first wiring conductor 24 are arranged with a gap therebetween, so that the flexibility of the sensor sheet 20 in the intersecting direction is improved. As a result, the attachability of the sensor sheet 20 to the steering wheel 10 is improved.

[0195] (Implementation 13)

[0196] Reference Figure 19-20, Embodiment 14 is described. In this embodiment, the shielding electrode 25 is arranged on the lower surface ( Fig.19 This embodiment is different from the first embodiment in that the second bypass conductor 26 and the second wiring conductor 27 are not included.

[0197] like Fig.19 As shown, the shield electrode 25 is arranged to overlap with the detection electrode 22 in the thickness direction of the insulating sheet 21 .

[0198] like Fig. 20 As shown in FIG. 1 , one end of the shield electrode 25 is formed as a non-contact region 25A that does not contact the lower surface of the insulator sheet 21. On the lower surface of the insulator sheet 21, a second bonding restriction layer 32 is arranged at a position corresponding to the non-contact region 25A of the shield electrode 25. The connection structure between the second lead 29 and the non-contact region 25A of the shield electrode 25 is almost the same as the connection structure between the second wiring conductor 27 and the second lead 29 described in the first embodiment, and therefore, repeated description is omitted.

[0199] According to this embodiment, the detection electrode 22 formed of a conductive elastic body is arranged on the upper surface of the insulating sheet 21, so the flexibility of the sensor sheet 20 is improved. As a result, the attachability of the sensor sheet 20 to the steering wheel 10 is improved.

[0200] (Implementation 14)

[0201] Reference Figure 21-22 , Embodiment 14 is described. In this embodiment, the sensor sheet 20 is different from Embodiment 1 in that the shielding electrode 25, the second bypass conductor 26, the second wiring conductor 27, the second bonding restriction layer 32, and the second lead 29 are not provided. In this embodiment, the surface of the insulating sheet 21 on the side opposite to the side where the detection electrode 22 is arranged is in contact with the resin inner layer material 16. In this embodiment, the core material 15 is connected to the ground potential. Therefore, in this embodiment, the shielding electrode 25 is not required.

[0202] According to this embodiment, since the sensor sheet 20 does not include the shield electrode 25 , the flexibility of the sensor sheet 20 is improved.

[0203] Furthermore, the sensor sheet 20 of the second to twelfth embodiments may be configured not to include the shield electrode 25 , the second bypass conductor 26 , the second wiring conductor 27 , the second junction restricting layer 32 , and the second lead 29 .

[0204] (Implementation 15)

[0205] Reference Fig.23Embodiment 15 will be described. In this embodiment, the sensor sheet 20 is different from Embodiment 14 in that it does not include the first wiring conductor 24. The first lead 28 is electrically connected to the detection electrode 22 by a known method.

[0206] According to this embodiment, since the sensor sheet 20 does not include the first wiring conductor 24 , the flexibility of the sensor sheet 20 is improved.

[0207] Furthermore, the sensor sheet 20 according to the first to twelfth embodiments may be configured not to include the first wiring conductor 24 .

[0208] (Implementation 16)

[0209] Reference Fig.24 Embodiment 16 will be described. This embodiment is different from Embodiment 1 in that the sensor sheet 20 does not include the second bypass conductor 26. According to this embodiment, since the sensor sheet 20 does not include the second bypass conductor 26, the flexibility of the sensor sheet 20 is improved.

[0210] Furthermore, the sensor sheet 20 according to the second to twelfth embodiments may be configured not to include the second bypass conductor 26 .

[0211] In this embodiment, the other end 27B of the second wiring conductor 27 is arranged near the central position in the crossing direction of the shielding electrode 25, but the present invention is not limited thereto. The other end 27B of the second wiring conductor 27 may be arranged at the side edge of the shielding electrode 25 that crosses the crossing direction, or may be arranged at any position. In addition, the second wiring conductor 27 may be omitted, and the second lead 29 may be electrically connected to the shielding electrode 25.

[0212] The present invention is not limited to the above-described embodiments, and can be applied to various embodiments within the scope not departing from the gist of the invention.

Claims

1. A sensor sheet (20) wound around a winding object member of a steering wheel (10) having a core material (15), wherein: The sensor sheet comprises: an insulator sheet (21) formed of an elastomer; at least one detection electrode (22), which is formed of an elastic body containing a conductive material and is disposed on the upper surface of the insulator sheet to form at least one detection area (22A); A first bypass conductor (23) disposed on an upper surface of the detection electrode and extending in a length direction corresponding to a direction of a central axis (14) of the winding object member; a first lead (28) corresponding to the detection electrode; and a first wiring conductor (24) disposed between the first bypass conductor and the first lead, spaced apart from the first bypass conductor and electrically connected to the detection electrode, One end (24A) of the first wiring conductor is electrically connected to the first lead and is arranged in contact with the first lead or at a position closer to the first lead than the first bypass conductor. The other end (24B) of the first wiring conductor is arranged at a position closer to the first bypass conductor than the one end of the first wiring conductor, and is arranged spaced apart from the first bypass conductor with a first end gap (41) therebetween.

2. The sensor sheet according to claim 1, wherein: The first wiring conductor is arranged at a distance in the longitudinal direction from one end of the first bypass conductor in the longitudinal direction, extends in a crossing direction crossing the longitudinal direction, and is electrically connected to the first lead.

3. The sensor sheet according to claim 2, wherein: The first wiring conductor extends linearly along the intersecting direction.

4. The sensor sheet according to claim 2, wherein: The first wiring conductor comprises: A first extension portion (61), which is electrically connected to the first lead and extends along the crossing direction; as well as A second extension portion (62) is bent from an end portion on the opposite side to the first lead wire in a direction approaching the first bypass conductor and extends along the longitudinal direction.

5. The sensor sheet according to claim 1, wherein: The first wiring conductor extends in the longitudinal direction from a position spaced apart in the longitudinal direction from one end of the first bypass conductor in the longitudinal direction and is electrically connected to the first lead.

6. The sensor sheet according to claim 1, wherein: The first wiring conductor is arranged at a distance from one end of the first bypass conductor in the longitudinal direction in a direction intersecting the longitudinal direction, and extends along the intersecting direction to be electrically connected to the first lead.

7. The sensor sheet according to claim 1, wherein: The first bypass conductor is composed of a plurality of first divided bypass conductors (23A) arranged in the longitudinal direction with first bypass intermediate gaps (40) therebetween.

8. The sensor sheet according to claim 7, wherein: The sensor sheet has a cutout portion (33) opening outward at at least one of the outer edges extending in the longitudinal direction, and a first bypass intermediate gap (40) is formed at a position corresponding to the cutout portion.

9. The sensor sheet according to claim 8, wherein: The width dimension of the cutout portion in the longitudinal direction is larger than that of the first bypass intermediate gap.

10. The sensor sheet according to claim 8, wherein The first bypass intermediate gap is smaller than the minimum width dimension of the detection object.

11. The sensor sheet according to claim 1, wherein: The first bypass conductor is formed of conductive fibers.

12. The sensor sheet according to claim 1, wherein: The first bypass conductor is formed of a metal wire.

13. The sensor sheet according to claim 1, wherein: The first bypass conductor is formed of an elastic body including a conductive material, and has a resistivity lower than that of the detection electrode.

14. The sensor sheet according to claim 1, wherein: The first bypass conductor is arranged in the detection area, At least a portion of the first wiring conductor is arranged in the detection region.

15. The sensor sheet according to claim 1, wherein The detection electrode includes an electrical connection region (22B), which is a region different from the detection region and electrically connects the first bypass conductor and the first wiring conductor. The first bypass conductor is arranged across the detection area and the electrical connection area. The first wiring conductor is arranged in the electrical connection region.

16. The sensor sheet according to any one of claims 1 to 15, wherein: The sensor sheet comprises: at least one shielding electrode (25), which is formed of an elastic body containing a conductive material and is disposed on the lower surface of the insulator sheet; a second bypass conductor (26) disposed on the lower surface of the shield electrode and extending along the length direction corresponding to the central axis direction of the winding object member; A second lead (29); as well as a second wiring conductor (27) disposed between the second bypass conductor and the second lead and spaced apart from the second bypass conductor; One end (27A) of the second wiring conductor is electrically connected to the second lead and is arranged in a state of contact with the second lead or arranged at a position closer to the second lead than the second bypass conductor. The other end (27B) of the second wiring conductor is arranged to be spaced apart from the second bypass conductor by a second end gap (43).

17. The sensor sheet according to claim 16, wherein: The second bypass conductor is composed of a plurality of second divided bypass conductors (26A) arranged in the longitudinal direction with a second bypass intermediate gap (42) therebetween.

18. The sensor sheet according to claim 17, wherein: The first bypass conductor is composed of a plurality of first divided bypass conductors (23A) arranged in the longitudinal direction with a first bypass intermediate gap (40) therebetween. The first end gap and the second end gap are arranged at positions overlapping in the thickness direction of the insulator sheet. The first bypass intermediate gap and the second bypass intermediate gap are arranged at positions overlapping with each other in a thickness direction of the insulator sheet.

19. A sensor sheet wound around a winding object member of a steering wheel having a core material, wherein: The sensor sheet comprises: an insulator sheet formed of an elastomer; at least one detection electrode, which is formed of an elastic body containing a conductive material, and is disposed on the upper surface of the insulator sheet to constitute at least one detection area; as well as a first bypass conductor disposed on an upper surface of each of the detection electrodes and extending in a longitudinal direction corresponding to a central axis direction of the winding object member; The first bypass conductor is composed of a plurality of first divided bypass conductors arranged in the longitudinal direction with first bypass intermediate gaps therebetween.

20. The sensor sheet according to claim 19, wherein The sensor sheet comprises: A first lead wire, which corresponds to the detection electrode; and a first wiring conductor disposed between the first bypass conductor and the first lead, The first wiring conductor is connected to one of the plurality of first division bypass conductors.

21. The sensor sheet according to claim 19, wherein The sensor sheet has a cutout portion opened outward at at least one of the outer edges in the longitudinal direction, and the first bypass intermediate gap is formed at a position corresponding to the cutout portion.

22. The sensor sheet according to claim 21, wherein: In the longitudinal direction, the width dimension of the cutout portion is larger than that of the first bypass intermediate gap.

23. The sensor sheet according to claim 19, wherein: The first bypass intermediate gap is smaller than the minimum width dimension of the detection object.

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