Electrostatic transducer and electrostatic transducer unit

Abstract

Provided is an electrostatic transducer which has a reduced film thickness and offers increased detection accuracy or operation accuracy. The electrostatic transducer (1) is provided with: an insulator sheet (11); a first electrode sheet (12) which is disposed on a front surface side of the insulator sheet (11) and has a plurality of first through-holes (12a) penetrating through the first electrode sheet (12) in a thickness direction thereof; and a second electrode sheet (13) which is disposed on a back surface side of the insulator sheet (11), wherein the second electrode sheet (13) either has no through-holes in the thickness direction thereof or has a plurality of second through-holes (13a) having an opening ratio smaller than that of the plurality of first through-holes (12a).

Description

[Technical field]

[0001] The present invention relates to an electrostatic transducer and an electrostatic transducer unit. [Background technology]

[0002] Electrostatic sensors that detect the approach or contact of a human finger or the like by a change in capacitance are known. Electrostatic actuators that utilize the change in capacitance are also known. For example, JP 2014-190856 A discloses that an electrostatic sensor is provided on a steering wheel to detect that the driver has released his / her hands. Furthermore, the steering wheel disclosed in JP 2014-190856 A discloses that a heater wire is wound around the outer periphery of the shaft core in a coil shape and an electrostatic sensor is disposed on the outer periphery of the heater wire, thereby providing a heater function. Furthermore, JP 5-172839 A discloses that electrodes provided on both sides of a piezoelectric film are made in a mesh shape, and the output voltage is controlled by changing the mesh degree. Summary of the Invention [Problem to be solved by the invention]

[0003] Electrostatic transducers (including sensors and actuators) are required to be made thin. However, making the thickness thinner increases the capacitance between the electrodes. When the capacitance increases, the current that flows increases, making it necessary to enlarge the power supply circuit. Therefore, by adopting mesh-shaped electrodes and reducing the mesh degree of the electrodes (electrode occupancy rate, area ratio of conductive components), the capacitance between the electrodes can be reduced. As a result, it is possible to make electrostatic transducers thin without enlarging the power supply circuit.

[0004] In addition, in an electrostatic transducer, one of a pair of electrodes may function as a shield electrode to prevent the transducer from being affected by external disturbances. By making one of the pair of electrodes function as a shield electrode, it is possible to improve the detection accuracy as a sensor or the operation accuracy as an actuator.

[0005] However, if the mesh density of the electrode is reduced in order to prevent the capacitance from increasing even when the electrode is made thin, the function as a shield electrode is reduced, which may result in a decrease in detection accuracy or operation accuracy.

[0006] The present invention has an object to provide an electrostatic transducer that can be thinned and has high detection accuracy or operation accuracy, and further has an object to provide a unit including the electrostatic transducer. [Means for solving the problem]

[0007] (1. Electrostatic transducer) A first aspect of the electrostatic transducer of the present invention includes an insulating sheet, a first electrode sheet disposed on a front surface side of the insulator sheet and having a plurality of first through holes penetrating in a thickness direction; a second electrode sheet disposed on a rear surface side of the insulator sheet and having a plurality of second through holes penetrating in a thickness direction; Equipped with an aperture ratio of the second through holes is smaller than an aperture ratio of the first through holes; The aperture ratio of the plurality of first through holes is 30% or more; the aperture ratio of the second through holes is less than 50%; The opening area of ​​each of the second through holes is smaller than the opening area of ​​each of the first through holes. Ku , The first electrode sheet has at least two detection regions, and the at least two detection regions have the first through holes having different opening areas. Found in electrostatic transducers. A second aspect of the electrostatic transducer of the present invention is , Absolute An edge sheet; a first electrode sheet disposed on a front surface side of the insulator sheet and having a plurality of first through holes penetrating in a thickness direction; The insulating sheet is disposed on the back side thereof, and the insulating sheet is disposed in the thickness direction thereof. Penetrate a second electrode sheet having a plurality of second through holes; Equipped with an aperture ratio of the second through holes is smaller than an aperture ratio of the first through holes; The aperture ratio of the plurality of first through holes is 30% or more; the aperture ratio of the second through holes is less than 50%; An opening area of ​​each of the second through holes is smaller than an opening area of ​​each of the first through holes, The first electrode sheet has at least two detection areas, and the at least two detection areas have different thicknesses. , in electrostatic transducers. A third aspect of the electrostatic transducer of the present invention includes an insulating sheet, a first electrode sheet disposed on a front surface side of the insulator sheet and having a plurality of first through holes penetrating in a thickness direction; a second electrode sheet disposed on a rear surface side of the insulator sheet and having a plurality of second through holes penetrating in a thickness direction; Equipped with an aperture ratio of the second through holes is smaller than an aperture ratio of the first through holes; The aperture ratio of the plurality of first through holes is 30% or more; the aperture ratio of the second through holes is less than 50%; An opening area of ​​each of the second through holes is smaller than an opening area of ​​each of the first through holes, The insulating sheet is made of an elastomer, the opposing surfaces of the first electrode sheet and the insulator sheet are fixed to each other by fusion of the insulator sheet itself, The opposing surfaces of the second electrode sheet and the insulator sheet are in an electrostatic transducer, to which the insulator sheet itself is fused. A fourth aspect of the electrostatic transducer of the present invention includes an insulating sheet, a first electrode sheet disposed on a front surface side of the insulator sheet and having a plurality of first through holes penetrating in a thickness direction; a second electrode sheet disposed on a rear surface side of the insulator sheet and having a plurality of second through holes penetrating in a thickness direction; Equipped with an aperture ratio of the second through holes is smaller than an aperture ratio of the first through holes; The aperture ratio of the plurality of first through holes is 30% or more; the aperture ratio of the second through holes is less than 50%; An opening area of ​​each of the second through holes is smaller than an opening area of ​​each of the first through holes, The insulating sheet in the electrostatic transducer is made of a styrene-based elastomer or an olefin-based elastomer. A fifth aspect of the electrostatic transducer of the present invention includes an insulating sheet, a first electrode sheet disposed on a front surface side of the insulator sheet and having a plurality of first through holes penetrating in a thickness direction; a second electrode sheet disposed on a rear surface side of the insulator sheet and having a plurality of second through holes penetrating in a thickness direction; An electrostatic transducer comprising: an aperture ratio of the second through holes is smaller than an aperture ratio of the first through holes; The aperture ratio of the plurality of first through holes is 30% or more; the aperture ratio of the second through holes is less than 50%; An opening area of ​​each of the second through holes is smaller than an opening area of ​​each of the first through holes, The electrostatic transducer further includes a heater sheet laminated on the rear surface side of the second electrode sheet. The electrostatic transducer of the present invention Sixth Aspect comprises an insulating sheet; a first electrode sheet disposed on a front surface side of the insulator sheet and having a plurality of first through holes penetrating in a thickness direction; a second electrode sheet disposed on a rear surface side of the insulator sheet and having a plurality of second through holes penetrating in a thickness direction; A heater sheet laminated on the back surface side of the second electrode sheet; Equipped with an aperture ratio of the second through holes is smaller than an aperture ratio of the first through holes; The opening area of ​​each of the second through holes in the electrostatic transducer is smaller than the opening area of ​​each of the first through holes.

[0008] In the electrostatic transducer of the present invention, whether the second electrode sheet has a configuration in which there is no through hole or a configuration in which there is a second through hole, the surface including the first electrode sheet has a smaller ratio of the area of ​​the portion that functions as an electrode per unit area (electrode occupancy rate) than the second electrode sheet.

[0009] In other words, the electrode occupancy rate per unit area can be reduced on the surface including the first electrode sheet arranged on the front side, and as a result, the capacitance between the electrodes can be reduced even if the distance between the electrodes is shortened. Therefore, the capacitance can be reduced while the electrostatic transducer is made thinner.

[0010] On the other hand, the surface including the second electrode sheet arranged on the back side has a larger electrode occupancy rate than the first electrode sheet. Therefore, the second electrode sheet can function as a shield electrode to reduce the influence of disturbances. As a result, the electrostatic transducer can improve the detection accuracy as a sensor or the operation accuracy as an actuator.

[0011] (2. Electrostatic transducer unit) A first aspect of the electrostatic transducer unit of the present invention is as follows: A core having a centerline; The electrostatic transducer described above, wherein the back surface of the second electrode sheet is disposed along an outer peripheral surface of the core material so as to face the outer peripheral surface centered on the center line of the core material; a resin inner layer material interposed between the outer circumferential surface of the core material and a rear surface of the electrostatic transducer and fixed to the core material and the electrostatic transducer; An electrostatic transducer unit comprising: In the electrostatic transducer, an end side in a circumferential direction of the outer circumferential surface of the core material is defined as a first end side, The two first end sides of the electrostatic transducer are disposed opposite to each other at a distance in the circumferential direction of the outer circumferential surface of the core material, The resin inner layer material is interposed in a gap between the two first end sides. , in the electrostatic transducer unit. A second aspect of the electrostatic transducer unit of the present invention includes a core material having a center line, an electrostatic transducer disposed along an outer circumferential surface of the core material so as to face the outer circumferential surface of the core material centered on the center line; a resin inner layer material interposed between the outer circumferential surface of the core material and a rear surface of the electrostatic transducer and fixed to the core material and the electrostatic transducer; An electrostatic transducer unit comprising: The electrostatic transducer is An insulating sheet; a first electrode sheet disposed on a front surface side of the insulator sheet and having a plurality of first through holes penetrating in a thickness direction; a second electrode sheet disposed on a rear surface side of the insulator sheet, the second electrode sheet having no through holes in a thickness direction or having a plurality of second through holes having an aperture ratio smaller than that of the plurality of first through holes; the electrostatic transducer is disposed along an outer circumferential surface of the core material such that a rear surface of the second electrode sheet faces an outer circumferential surface of the core material centered on the center line of the core material; In the electrostatic transducer, an end side in a circumferential direction of the outer circumferential surface of the core material is defined as a first end side, The two first end sides of the electrostatic transducer are disposed opposite to each other at a distance in the circumferential direction of the outer circumferential surface of the core material, The resin inner layer material is in an electrostatic transducer unit interposed in the gap between the two first end sides.

[0012] When the electrostatic transducer is disposed along the outer circumferential surface of the core material, the resin inner layer material is disposed between the outer circumferential surface of the core material and the back surface of the electrostatic transducer, and the resin inner layer material is fixed to the outer circumferential surface of the core material and the back surface of the electrostatic transducer, thereby preventing the electrostatic transducer from peeling off from the core material.

[0013] Furthermore, by placing a resin inner layer material in the gap between the two opposing ends of the electrostatic transducer, the design of the electrostatic transducer unit is improved. Also, by using a resin inner layer material, the electrostatic transducer unit can be easily manufactured. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is a longitudinal sectional view of a first example of a transducer. [Figure 2A] FIG. 2 is a longitudinal sectional view of a first electrode sheet constituting a first example of a transducer. [Figure 2B] FIG. 2 is a cross-sectional view of a first electrode sheet. [Figure 3A] FIG. 2 is a longitudinal cross-sectional view of a second electrode sheet constituting the first example of the transducer. [Figure 3B] FIG. 2 is a cross-sectional view of a second electrode sheet. [Figure 4] 4A to 4C are diagrams illustrating a manufacturing method of a first example transducer. [Diagram 5] FIG. 11 is a longitudinal sectional view of a second example of a transducer. [Figure 6] FIG. 13 is a longitudinal sectional view of a transducer according to a third example. [Figure 7] FIG. 11 is a cross-sectional view of a first electrode sheet constituting a third example of a transducer. [Figure 8] FIG. 13 is a longitudinal sectional view of a fourth example of a transducer. [Figure 9] FIG. 11 is a longitudinal sectional view of a first electrode sheet constituting a fourth example of a transducer. [Figure 10] FIG. 13 is a longitudinal sectional view of a transducer according to a fifth example. [Figure 11] FIG. 13 is a longitudinal sectional view of a transducer according to a sixth example. [Figure 12] 13A to 13C are diagrams illustrating a manufacturing method of a sixth example transducer. [Figure 13] FIG. 2 is a front view of a steering wheel as a first example of a transducer unit. [Figure 14] 14 is an enlarged cross-sectional view taken along line AA in FIG. 13. [Figure 15] 13A and 13B are diagrams showing a transducer applied to a transducer unit according to a second example. [Figure 16] 14 is an enlarged cross-sectional view of the transducer unit according to the second embodiment taken along line AA in FIG. 13. [Figure 17] 14 is an enlarged cross-sectional view of the transducer unit according to the third embodiment taken along line AA in FIG. 13. [Figure 18] 13 is a flowchart illustrating a manufacturing method of a transducer unit according to a fourth example. [Figure 19] FIG. 13 is a diagram showing a transducer applied to a transducer unit of a fourth example. [Figure 20] FIG. 2 is a front view of a pre-molded transducer. [Figure 21] 21 is an enlarged cross-sectional view of FIG. 20 shown in FIG. [Figure 22] FIG. 2 is a cross-sectional view before injection molding. [Diagram 23] FIG. 3 is a cross-sectional view after injection molding. [Figure 24] FIG. 2 is a cross-sectional view showing a state in which the mold has been removed after injection molding. [Diagram 25] 14 is an enlarged cross-sectional view of the transducer unit according to the fourth embodiment taken along line AA in FIG. 13. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] (1. Application of electrostatic transducers) An electrostatic transducer (hereinafter referred to as a "transducer") includes, for example, a substrate and an electrostatic sheet attached to the attachment surface of the substrate. The substrate is an arbitrary member and is formed of metal, resin, or other material.

[0016] The mounting surface of the substrate may be formed into a three-dimensional shape such as a curved surface, a composite plane, or a composite shape of a plane and a curved surface, or the surface of the substrate may be formed into a single plane shape. When the substrate is made of a flexible material, the electrostatic sheet may be attached to the mounting surface of the substrate. The transducer may also be used as the electrostatic sheet alone, without including a substrate.

[0017] The electrostatic sheet can function as an actuator that generates vibrations, sounds, etc. by utilizing the change in electrostatic capacitance between the electrodes. The electrostatic sheet can also function as a sensor that detects an external pressing force, etc., or a sensor that detects contact or proximity of a conductor by utilizing the change in electrostatic capacitance between the electrodes.

[0018] When the electrostatic sheet functions as an actuator, a voltage is applied to the electrodes, and the insulator deforms in response to the potential between the electrodes, and vibration occurs with the deformation of the insulator. When the electrostatic sheet functions as a pressing force detection sensor, the capacitance between the electrodes changes as the insulator deforms due to an input such as an external pressing force, vibration, or sound, and the pressing force from the outside is detected by detecting a voltage corresponding to the capacitance between the electrodes. When the electrostatic sheet functions as a contact / proximity sensor, the capacitance between the electrodes changes due to the contact or proximity of a conductor, and the contact or proximity of the conductor is detected by detecting a voltage corresponding to the changed capacitance between the electrodes.

[0019] The transducer can be applied to, for example, the surface of a mouse or joystick, which is a pointing device, or the surface of a vehicle part. The vehicle parts include an armrest, a doorknob, a shift lever, a steering wheel, a door trim, a center trim, a center console, a ceiling, and the like. In many cases, the base material is made of a material that does not have flexibility, such as a metal or a hard resin. The transducer can detect the state of a subject and apply vibrations or the like to the subject.

[0020] The transducer may be disposed on the surface of the seat. In this case, the transducer may be configured by attaching an electrostatic sheet to a base material formed of a flexible material such as a resin film. The transducer may be configured by the electrostatic sheet alone without a base material.

[0021] The electrostatic sheet of the transducer can also be configured to have a heater function, in which case the transducer can apply heat to the subject in addition to detecting the subject's condition and applying vibrations to the subject.

[0022] (2. First Example) (2-1. Configuration of the Transducer 1 in the First Example) The configuration of a first example of a transducer 1 will be described with reference to Figs. 1 to 3B. As shown in Fig. 1, the transducer 1 includes at least an electrostatic sheet 10. In the first example, the transducer 1 includes a substrate 20 and a substrate-side fusion sheet 30, but the transducer 1 may also be configured without the substrate 20 and the substrate-side fusion sheet 30. The substrate 20 is formed of any material such as metal or resin.

[0023] The electrostatic sheet 10 is elastically deformable as a whole. The electrostatic sheet 10 is attached to the attachment surface of the substrate 20. Even if the attachment surface of the substrate 20 is a three-dimensional curved surface, the electrostatic sheet 10 can be attached along the curved attachment surface of the substrate 20. In particular, by attaching the electrostatic sheet 10 to the attachment surface of the substrate 20 while stretching the electrostatic sheet 10 in the planar direction, it is possible to prevent wrinkles from occurring in the electrostatic sheet 10.

[0024] The electrostatic sheet 10 includes at least an insulating sheet 11, a first electrode sheet 12, and a second electrode sheet 13. The insulating sheet 11 is made of an elastomer. Therefore, the insulating sheet 11 is elastically deformable. The insulating sheet 11 is made of, for example, a thermoplastic elastomer. The insulating sheet 11 may be made of a thermoplastic elastomer itself, or may be made of an elastomer that is crosslinked by heating a thermoplastic elastomer as a material.

[0025] Here, the insulating sheet 11 can be made of one or more elastomers selected from styrene-based, olefin-based, PVC-based, urethane-based, ester-based, amide-based, etc. For example, styrene-based elastomers include SBS, SEBS, SEPS, etc. Olefin-based elastomers include EEA, EMA, EMMA, etc., as well as copolymers of ethylene and α-olefins (ethylene-octene copolymers).

[0026] The insulating sheet 11 may contain a rubber or resin other than a thermoplastic elastomer. For example, when the insulating sheet 11 contains a rubber such as ethylene-propylene rubber (EPM, EPDM), the flexibility of the insulating sheet 11 is improved. From the viewpoint of improving the flexibility of the insulating sheet 11, the insulating sheet may contain a flexibility-imparting component such as a plasticizer.

[0027] The first electrode sheet 12 is disposed on the front surface (upper surface in FIG. 1) of the insulator sheet 11. The first electrode sheet 12 is conductive, flexible, and stretchable in the planar direction. The first electrode sheet 12 is formed of, for example, a conductive elastomer, a conductive cloth, a metal sheet, or the like.

[0028] Furthermore, as shown in FIG. 1, FIG. 2A, and FIG. 2B, the first electrode sheet 12 has a plurality of first through holes 12a penetrating in the thickness direction. The first through holes 12a refer to a region (insulating region) where no conductive component exists. That is, the surface including the first electrode sheet 12 is composed of a conductive region where the first electrode sheet 12 exists and an insulating region where the first through holes 12a exist. The first through holes 12a may be voids, or an insulating elastomer or the like may exist. In FIG. 1, FIG. 2A, and FIG. 2B, the first electrode sheet 12 is illustrated as having the first through holes 12a as voids.

[0029] When the transducer 1 is used as a sensor for detecting the approach or contact of a human finger, the aperture ratio of the first through holes 12a is preferably 30% or more. The aperture ratio of the first through holes 12a is preferably 50% or more, and more preferably 60% or more. The aperture ratio of the first through holes 12a means the ratio of an area formed only by an insulating material (including holes, insulating elastomer, etc.) in a given area when the first electrode sheet 12 is viewed from the normal direction. In other words, the aperture ratio is the ratio of the first through holes 12a per unit area in the surface including the first electrode sheet 12.

[0030] In addition, the ratio of the portion that functions as an electrode per unit area on the surface including the first electrode sheet 12 (electrode occupancy rate) is the ratio obtained by subtracting the aperture rate from 100%. Therefore, the electrode occupancy rate of the first electrode sheet 12 is less than 70%, preferably less than 50%, and more preferably less than 40%.

[0031] Furthermore, the first electrode sheet 12 is fixed to the insulator sheet 11 by fusing (e.g., thermal fusing) the insulator sheet 11 itself. That is, a portion of the front surface side of the insulator sheet 11 functions as a fusing material for fixing to the first electrode sheet 12. Therefore, the first electrode sheet 12 and the insulator sheet 11 are fixed to each other without using a volatile adhesive or an organic solvent.

[0032] Since the first electrode sheet 12 has the first through-holes 12a, a portion of the front surface side of the insulator sheet 11 can fit into the first through-holes 12a. In this manner, the first electrode sheet 12 is embedded in the insulator sheet 11. That is, the first electrode sheet 12 is fixed by the portion of the insulator sheet 11 that fits into the first through-holes 12a. Therefore, the insulator sheet 11 and the first electrode sheet 12 are more firmly integrated.

[0033] In the first example, the first electrode sheet 12 is made of a conductive elastomer. The conductive elastomer is an elastomer containing a conductive filler.

[0034] The elastomer used in the first electrode sheet 12 is preferably formed from a material having the same main component as that of the insulator sheet 11. That is, the first electrode sheet 12 can be made of one or more elastomers selected from styrene-based, olefin-based, PVC-based, urethane-based, ester-based, amide-based, and other elastomers. For example, styrene-based elastomers include SBS, SEBS, and SEPS. Olefin-based elastomers include EEA, EMA, EMMA, and other elastomers, as well as copolymers of ethylene and α-olefins (ethylene-octene copolymers).

[0035] However, the first electrode sheet 12 is designed to have a higher softening point than the insulator sheet 11. This is so that when the first electrode sheet 12 is fixed to the insulator sheet 11 by fusing (e.g., thermal fusing) the insulator sheet 11 itself, the insulator sheet 11 can soften before the first electrode sheet 12. Also, in the first example, the first through-holes 12a may be formed, for example, by punching after molding a conductive sheet having no through-holes.

[0036] When the transducer 1 is used as a sensor for detecting the approach or contact of a human finger, the first through-holes 12a must be large enough to detect the human finger. That is, the opening area of ​​each first through-hole 12a is formed to a size corresponding to a human finger. That is, the opening area of ​​each first through-hole 12a is formed to be sufficiently small with respect to the contact area of ​​a human finger as a reference.

[0037] Specifically, the diameter of the maximum inscribed circle of the first through hole 12a is preferably set to 150 μm or more and 15 mm or less. As shown in FIG. 2B, when the first through hole 12a is a circular hole, the inner diameter of the first through hole 12a is equal to the diameter of the maximum inscribed circle. When the first through hole 12a is an ellipse, the minor axis of the ellipse is the diameter of the maximum inscribed circle. When the first through hole 12a is a rectangle, the distance between the opposing shorter sides of the rectangle is the diameter of the maximum inscribed circle. For example, when the first electrode sheet 12 is a conductive fabric, the diameter of the maximum inscribed circle is the shorter of the interval between adjacent warps or the interval between adjacent wefts.

[0038] Furthermore, the opening area of ​​each of the first through holes 12a is 6400 μm 2 More than 225mm 2 It is preferable that the diameter of the maximum inscribed circle of the first through hole 12a is set within the above range, and the opening area is also set within the above range.

[0039] As described above, by setting the diameter of the maximum inscribed circle of the first through holes 12a to 150 μm or more, the first through holes 12a are enlarged (the periphery of the first through holes 12a is expanded) when covering the surface of an object having a three-dimensional shape, making it easier to cover the surface. 2 The above also provides the same effect.

[0040] The maximum diameter of the maximum inscribed circle of the first through holes 12a is 15 mm, which corresponds to the width that a human finger can touch. This allows the transducer 1 to be used reliably as a sensor for detecting the touch of a human finger. Also, the maximum opening area of ​​each first through hole 12a is set to 225 mm. 2 By satisfying the following, the sensor can be reliably used to detect contact with a human finger.

[0041] Therefore, when the transducer 1 is a sensor for detecting a human finger, the diameter of the maximum inscribed circle of the first through holes 12a should be set to a value close to 15 mm. That is, the diameter of the maximum inscribed circle of the first through holes 12a is preferably set to 5 mm or more and 15 mm or less, and more preferably 10 mm or more and 15 mm or less. Also, the opening area of ​​each of the first through holes 12a is set to 225 mm. 2 That is, the opening area of ​​each first through hole 12a is preferably 100 mm 2 More than 225mm 2 It is set to 150 mm or less, more preferably 2 More than 225mm 2 The following is the result.

[0042] The second electrode sheet 13 is disposed on the back surface (lower surface in FIG. 1) of the insulator sheet 11. The second electrode sheet 13 faces the first electrode sheet 12. Like the first electrode sheet 12, the second electrode sheet 13 has electrical conductivity, flexibility, and stretchability in the planar direction. The second electrode sheet 13 is formed of the same material as the first electrode sheet 12.

[0043] Furthermore, the second electrode sheet 13 is fixed to the insulator sheet 11 by fusing (e.g., thermal fusing) the insulator sheet 11 itself. That is, a portion of the back surface side of the insulator sheet 11 functions as a fusing material for fixing to the second electrode sheet 13. Therefore, the second electrode sheet 13 and the insulator sheet 11 are fixed to each other without using a volatile adhesive or an organic solvent.

[0044] The second electrode sheet 13 may have no through holes in the thickness direction, or may have a plurality of second through holes 13a as shown in Figures 1, 3A, and 3B. The second through holes 13a refer to regions where no conductive components exist (insulating regions).

[0045] When the second electrode sheet 13 does not have a through hole, the conductive component is present over the entire surface area. When the second electrode sheet 13 is made to function as a shield electrode, the second electrode sheet 13 exhibits the maximum shielding function when it does not have a through hole.

[0046] On the other hand, when the second electrode sheet 13 has the second through-holes 13a, the second electrode sheet 13 is composed of a conductive region where the second electrode sheet 13 exists and an insulating region where the second through-holes 13a exist. The second through-holes 13a may be voids, similar to the first through-holes 12a, or may contain an insulating elastomer or the like. In Fig. 1, Fig. 3A, and Fig. 3B, the second electrode sheet 13 is illustrated having the second through-holes 13a as voids.

[0047] In addition, when the second electrode sheet 13 is made to function as a shield electrode, the second through holes 13a may have a smaller aperture ratio than the first through holes. The aperture ratio of the second through holes 13a may be less than 50%. The preferred aperture ratio of the second through holes 13a is less than 40%, and further less than 30%. The aperture ratio of the second through holes 13a means the ratio of a region formed only by an insulating material (including pores, insulating elastomers, etc.) in a given region when the second electrode sheet 13 is viewed from the normal direction. In other words, the aperture ratio is the ratio of the second through holes 13a per unit area in the surface including the second electrode sheet 13.

[0048] In addition, in the surface including the second electrode sheet 13, the ratio of the portion that functions as an electrode per unit area (electrode occupancy rate) is the ratio obtained by subtracting the aperture rate from 100%. Therefore, the electrode occupancy rate of the second electrode sheet 13 is 50% or more, preferably 60% or more, and more preferably 70% or more. In other words, the electrode occupancy rate of the surface including the second electrode sheet 13 is larger than that of the surface including the first electrode sheet 12.

[0049] Furthermore, the opening area of ​​each of the second through holes 13a is smaller than the opening area of ​​each of the first through holes 12a. When the transducer 1 is used as a sensor for detecting the approach or contact of a human finger, as described above, the opening area of ​​each of the first through holes 12a needs to be large enough to detect a human finger. On the other hand, each of the second through holes 13a is made sufficiently small relative to a human finger.

[0050] Specifically, the diameter of the smallest circumscribing circle of the second through hole 13a is preferably set to 0 mm or more and 10 mm or less. As shown in FIG. 3B, when the second through hole 13a is a circular hole, the inner diameter of the second through hole 13a is equal to the diameter of the smallest circumscribing circle. When the second through hole 13a is an ellipse, the major axis of the ellipse is the diameter of the smallest circumscribing circle. When the second through hole 13a is a rectangle, the distance between the diagonals of the rectangle is the diameter of the smallest circumscribing circle.

[0051] Furthermore, the opening area of ​​each second through hole 13a is 0 m 2 More than 100mm 2 It is preferable that the diameter of the minimum circumscribing circle of the second through hole 13a is set within the above range, and the opening area is also set within the above range.

[0052] Furthermore, when the second electrode sheet 13 has a second through hole 13a, a part of the back surface side of the insulator sheet 11 can be made to fit into the second through hole 13a. In this manner, the second electrode sheet 13 is embedded in the insulator sheet 11. In this case, the second electrode sheet 13 is fixed by the part of the insulator sheet 11 that fits into the second through hole 13a. Therefore, the insulator sheet 11 and the second electrode sheet 13 are more firmly integrated.

[0053] Here, in the first example, the second electrode sheet 13 is formed of a conductive elastomer similar to the first electrode sheet 12. The elastomer used for the second electrode sheet 13 is similar to that used for the first electrode sheet 12. Also, the second through holes 13a may be formed, for example, by punching after forming a conductive sheet having no through holes.

[0054] The substrate-side fusion sheet 30 is formed of the same material as the insulator sheet 11. The substrate-side fusion sheet 30 is fixed to the mounting surface of the substrate 20 and to the rear surface of the second electrode sheet 13 by its own fusion (for example, thermal fusion).

[0055] (2-2. Manufacturing method of the transducer 1 of the first example) A manufacturing method of the transducer 1 of the first example will be described with reference to Fig. 4. As shown in Fig. 4, a first electrode sheet 12 is arranged on the front side of an insulating sheet 11, and a second electrode sheet 13 is arranged on the back side of the insulating sheet 11 (preparation step). In this manner, a laminate is prepared.

[0056] Next, the prepared laminate is heated and pressurized in the stacking direction (first heating and pressurizing step). This softens the surface of the insulator sheet 11, and at least a portion of the first electrode sheet 12 is embedded from the surface of the insulator sheet 11. The surface of the insulator sheet 11 then functions as a fusion material, and the first electrode sheet 12 is fixed to the insulator sheet 11. Furthermore, the back surface of the insulator sheet 11 softens, and at least a portion of the second electrode sheet 13 is embedded from the back surface of the insulator sheet 11. The back surface of the insulator sheet 11 then functions as a fusion material, and the second electrode sheet 13 is fixed to the insulator sheet 11.

[0057] Next, in a state in which the surface of the substrate-side fusion sheet 30 is heated and softened, the back side of the second electrode sheet 13 that has been integrated in the first heating and pressing step is pressed against the surface of the substrate-side fusion sheet 30 (second heating and pressing step). Then, the back side of the second electrode sheet 13 is fixed to the substrate-side fusion sheet 30 by the fusion of the substrate-side fusion sheet 30 itself.

[0058] Next, in a state in which the back surface of the substrate-side fusion sheet 30 is heated and softened, the mounting surface of the substrate 20 is pressed against the back surface of the substrate-side fusion sheet 30 (third heating and pressing step). As a result, the substrate-side fusion sheet 30 itself is fused, and the mounting surface of the substrate 20 is fixed to the substrate-side fusion sheet 30. In this manner, the transducer 1 is manufactured.

[0059] Here, a crosslinking agent may be contained in the material of the insulator sheet 11. In this case, by heating in the first heating and pressing step, the insulator sheet 11 can be crosslinked at the same time as the insulator sheet 11 is fixed by fusion. After the first heating and pressing step, the insulator sheet 11 is formed of a crosslinked elastomer.

[0060] Furthermore, when a crosslinking agent is contained in the material of the insulator sheet 11, additional heating for crosslinking can be performed after the first heating and pressurizing step (crosslinking step). In this case, after the insulator sheet 11 is fixed by fusion, the insulator sheet 11 can be crosslinked by additional heating. In this case, after the crosslinking step in which additional heating is performed, the insulator sheet 11 will be formed of a crosslinked elastomer.

[0061] In the first heating and pressing step, the step of bonding the first electrode sheet 12 and the insulator sheet 11 and the step of bonding the second electrode sheet 13 and the insulator sheet 11 may be performed separately. The substrate-side fusion sheet 30 may be bonded to the substrate 20 before being bonded to the second electrode sheet 13 in an integrated state in the first heating and pressing step. In addition, when the substrate 20 does not exist, the substrate-side fusion sheet 30 may also be unnecessary.

[0062] (2-3. Effect of transducer 1 in the first example) According to the first example transducer 1, whether the second electrode sheet 13 has a configuration in which there is no through hole or a configuration in which there is a second through hole 13a, the surface including the first electrode sheet 12 has a smaller ratio of the area of ​​the portion that functions as an electrode per unit area (electrode occupancy rate) than the surface including the second electrode sheet 13.

[0063] In other words, the electrode occupancy rate per unit area can be reduced on the surface including the first electrode sheet 12 arranged on the front side, and as a result, the capacitance between the electrodes can be reduced even if the distance between the electrodes is shortened. Therefore, the capacitance can be reduced while the transducer 1 is made thin.

[0064] On the other hand, the surface including the second electrode sheet 13 arranged on the back side has a larger electrode occupancy rate than the surface including the first electrode sheet. Therefore, the second electrode sheet 13 can function as a shield electrode to reduce the influence of disturbances. As a result, the transducer 1 can improve the detection accuracy as a sensor and the operation accuracy as an actuator.

[0065] (3. Transducer 2 in the second example) The configuration of the transducer 2 of the second example will be described with reference to Fig. 5. The transducer 2 of the second example includes a first electrode sheet 14 and a second electrode sheet 15 instead of the first electrode sheet 12 and the second electrode sheet 13 of the transducer 1 of the first example. In the second example, the same components as those in the first example are denoted by the same reference numerals and will not be described.

[0066] In the second example, the first electrode sheet 14 and the second electrode sheet 15 are formed of conductive cloth. The conductive cloth is a woven or nonwoven fabric formed of conductive fibers. Here, the conductive fibers are formed, for example, by coating the surface of a flexible fiber with a conductive material. The conductive fibers are formed, for example, by plating the surface of a resin fiber such as polyethylene with copper or nickel.

[0067] Therefore, the first electrode sheet 14 has a plurality of first through holes 14a, and the second electrode sheet 15 has a plurality of second through holes 15a. The aperture ratio of the second through holes 15a is smaller than the aperture ratio of the first through holes 14a. In other words, the electrode occupancy ratio of the second electrode sheet 15 is larger than the electrode occupancy ratio of the first electrode sheet 12.

[0068] For example, the conductive threads constituting the first electrode sheet 14 are made thicker than the conductive threads constituting the second electrode sheet 15, and the first electrode sheet 14 is braided relatively coarsely, while the second electrode sheet 15 is braided relatively finely. In this way, the second through holes 15a can be made smaller than the first through holes 14a.

[0069] The transducer 2 of the second example also has the same effects as the transducer 1 of the first example. That is, the transducer 2 can be made thin and the detection accuracy and operation accuracy can be improved.

[0070] Furthermore, compared to the first example, at least a portion of the first electrode sheet 14 can be made to be embedded deeper in the insulator sheet 11. For example, if the surface of the first electrode sheet 14 is formed to be uneven, the concave portions of the surface will be embedded deeper in the insulator sheet 11.

[0071] In this case, the insulator sheet 11 has a first covering layer 11a formed of a part of the surface side of the insulator sheet 11 on the surface side of the first electrode sheet 14. Therefore, at least a part of the surface of the first electrode sheet 14 is fixed to the first covering layer 11a by fusion of the first covering layer 11a itself. As a result, the insulator sheet 11 and the first electrode sheet 14 are more firmly integrated.

[0072] Like the first electrode sheet 14, at least a portion of the second electrode sheet 15 can be made to be embedded even deeper in the insulator sheet 11. For example, when the back surface of the second electrode sheet 15 is formed in an uneven shape, the concave portions of the back surface are made to be embedded even deeper in the insulator sheet 11.

[0073] In this case, the insulator sheet 11 has a second covering layer 11b formed of a part of the back surface of the insulator sheet 11 on the back surface side of the second electrode sheet 15. Therefore, at least a part of the back surface of the second electrode sheet 15 is fixed to the second covering layer 11b by fusion of the second covering layer 11b itself. As a result, the insulator sheet 11 and the second electrode sheet 15 are more firmly integrated.

[0074] (4. Transducer 3 of the third example) The configuration of the transducer 3 of the third example will be described with reference to Figures 6 and 7. The transducer 3 of the third example includes a first electrode sheet 16 instead of the first electrode sheet 12 of the transducer 1 of the first example. In the third example, the same components as those in the first example are denoted by the same reference numerals and will not be described.

[0075] In the third example, the first electrode sheet 16 has at least two detection regions P1, P2 as shown in FIG. 7. The first electrode sheet 16 may have two detection regions P1, P2, or may have three or more detection regions. The detection regions P1, P2 have first through holes 16a, 16b with different opening areas. That is, the first through hole 16a formed in the first detection region P1 and the first through hole 16b formed in the second detection region P2 have different opening areas. In FIG. 7, the first through hole 16a in the first detection region P1 has a smaller opening area than the first through hole 16b in the second detection region P2.

[0076] Therefore, in the first electrode sheet 16, the electrode occupancy rate differs depending on the detection areas P1, P2. For example, when a human finger approaches or touches, the detected capacitance differs. As a result, even when a plurality of detection areas P1, P2 are formed by one first electrode sheet 16, the position where the human finger approaches or touches can be detected based on the difference in capacitance. The shape of the first through holes 16a, 16b is not limited to a circular shape, and can be various shapes.

[0077] (5. Transducer 4 of the fourth example) The configuration of the transducer 4 of the fourth example will be described with reference to Figures 8 and 9. The transducer 4 of the fourth example includes a first electrode sheet 17 instead of the first electrode sheet 12 of the transducer 1 of the first example. In the fourth example, the same components as those in the first example are denoted by the same reference numerals and descriptions thereof will be omitted.

[0078] In the fourth example, the first electrode sheet 17 has at least two detection areas P3, P4 as shown in Fig. 9. The first electrode sheet 17 may have two detection areas P3, P4, or may have three or more detection areas. The detection areas P3, P4 have different thicknesses. Here, the multiple first through holes 17a have the same shape.

[0079] That is, a portion 171 of the first detection region P3 in the first electrode sheet 17 and a portion 172 of the second detection region P4 in the first electrode sheet 17 have different thicknesses. In Fig. 8 and Fig. 9, the portion 171 of the first detection region P3 is thicker than the portion 172 of the second detection region P4. Furthermore, the first electrode sheet 17 is disposed such that a step due to the difference in thickness is located on the front surface side of the first electrode sheet 17.

[0080] When a human finger approaches, the detected capacitance is different. As a result, even if a plurality of detection regions P3 and P4 are formed by one first electrode sheet 17, the position where the human finger approaches can be detected based on the difference in capacitance. Note that, although the first through-holes 17a have the same shape in the first detection region P3 and the second detection region P4, they may have different shapes.

[0081] (6. Fifth Example Transducer 5) The configuration of the transducer 5 of the fifth example will be described with reference to Fig. 10. The transducer 5 of the fifth example includes a first electrode sheet 18 instead of the first electrode sheet 17 of the transducer 4 of the fourth example. In the fifth example, the same components as those in the fourth example are denoted by the same reference numerals and will not be described.

[0082] In the fifth example, the first electrode sheet 18 has a different thickness, similar to the first electrode sheet 17 in the fourth example. That is, the first electrode sheet 18 has at least two detection areas P5, P6 as shown in FIG. 10. The first electrode sheet 18 may have two detection areas P5, P6, or may have three or more detection areas. The detection areas P5, P6 have different thicknesses. That is, the area 181 of the first detection area P5 in the first electrode sheet 18 and the area 182 of the second detection area P6 in the first electrode sheet 18 have different thicknesses. Here, the multiple first through holes 18a have the same shape.

[0083] The first electrode sheet 18 is disposed so that a step due to the difference in thickness is located on the back surface side of the first electrode sheet 18. In other words, the distance between the back surface of the first electrode sheet 18 and the front surface of the second electrode sheet 13 is different between the first detection region P5 and the second detection region P6.

[0084] Therefore, when a human finger approaches or touches the area, the detected capacitance is different. As a result, even when a plurality of detection areas P5, P6 are formed by one first electrode sheet 18, the position where the human finger approaches or touches the area can be detected based on the difference in capacitance. Note that, although the first through-holes 18a have the same shape in the first detection area P5 and the second detection area P6, they may have different shapes.

[0085] (7. Transducer 6 of the sixth example) (7-1. Configuration of transducer 6 in the sixth example) The configuration of the transducer 6 of the sixth example will be described with reference to Fig. 11. As shown in Fig. 11, the transducer 6 includes an electrostatic sheet 10, a substrate 20, and a heater sheet 40 disposed between the rear surface of the electrostatic sheet 10 and the front surface of the substrate 20. That is, the transducer 6 has a heater function in addition to a sensor or actuator function.

[0086] Here, the electrostatic sheet 10 can be any of the electrostatic sheets 10 in the above-mentioned examples of the transducers 1, 2, 3, 4, and 5. However, the insulating sheet 11 constituting the electrostatic sheet 10 is preferably made of the following materials so that the heat of the heater sheet 40 can be transferred to the surface of the electrostatic sheet 10 and so that heat resistance is ensured.

[0087] The thermal conductivity of the insulator sheet 11 is 0.3 W / m·K or more. A suitable thermal conductivity is 0.4 W / m·K or more, and further 0.5 W / m·K or more. The insulator sheet 11 desirably has a relatively high thermal conductivity and contains an insulating inorganic filler. A suitable thermal conductivity of the inorganic filler (thermally conductive filler) used to increase the thermal conductivity of the insulator sheet 11 is 5 W / m·K or more, preferably 10 W / m·K or more, and more preferably 20 W / m·K or more. Examples of inorganic fillers with a relatively high thermal conductivity include metal fillers such as magnesium oxide, aluminum oxide, and aluminum nitride. In addition to metal fillers, boron nitride, silicon carbide, and the like can also be used as inorganic fillers with a relatively high thermal conductivity.

[0088] From the viewpoint of imparting flame retardancy to the insulator sheet 11, the insulator sheet 11 preferably contains a flame-retardant and insulating inorganic filler. Examples of the flame-retardant filler include hydroxide fillers such as magnesium hydroxide and aluminum hydroxide. In addition to hydroxide fillers, boron nitride and the like can also be used as the flame-retardant filler. The flame-retardant filler can also be used as an inorganic filler (thermally conductive filler) used to increase the thermal conductivity of the insulator sheet 11.

[0089] From the viewpoint of ensuring the insulation of the insulator sheet 11, the volume resistivity of the insulator sheet 11 is set to 1×10 12 The volume resistivity is preferably 1×10 13 Ω·cm or more.

[0090] The heater sheet 40 is disposed on the back side of the electrostatic sheet 10, i.e., the back side of the second electrode sheet 13. The heater sheet 40 includes a heater wire 41 and a heater insulating layer 42 that covers the heater wire 41. The heater wire 41 is a metal alloy material such as nickel chromium or iron chromium. The heater wire 41 is formed into a sheet shape, for example, by forming a wire material back and forth or by winding it in a spiral shape.

[0091] The heater insulating layer 42 is disposed so as to surround the heater wire 41 and prevent the heater wire 41 from being exposed. The heater insulating layer 42 may be formed of the same material as the insulator sheet 11. Furthermore, a portion of the front surface side of the heater insulating layer 42 is fixed to the rear surface of the second electrode sheet 13 by self-fusion (e.g., thermal fusion). Furthermore, the front surface side of the heater insulating layer 42 is also fixed to the exposed rear surface of the insulator sheet 11 by self-fusion. Furthermore, a portion of the rear surface side of the heater insulating layer 42 is fixed to the mounting surface of the substrate 20 by self-fusion (e.g., thermal fusion).

[0092] (7-2. Manufacturing method of transducer 6 of the sixth example) A manufacturing method of the transducer 6 of the sixth example will be described with reference to Fig. 12. A heater sheet laminate in which the first material 42a of the heater insulating layer 42, the heater wire 41, and the second material 42b of the heater insulating layer 42 are laminated in this order is prepared (heater sheet preparation step).

[0093] Next, the prepared heater sheet laminate is heated and pressurized (heater sheet heating and pressurizing process). As a result, the first material 42a and the second material 42b are softened and function as fusion materials, and are fixed to the heater wire 41. Furthermore, the first material 42a and the second material 42b are fixed to each other and integrated to form the heater insulating layer 42. In this manner, the heater sheet 40 is formed.

[0094] Next, the electrostatic sheet 10 and the heater sheet 40 are prepared (preparation step). The surface of the heater sheet 40 is heated (heater sheet heating step). Then, the electrostatic sheet 10 and the heater sheet 40 are pressed together with the back side of the electrostatic sheet 10 in contact with the front side of the heater sheet 40 (pressure step). As a result, the front side of the heater insulating layer 42 softens and functions as a fusion material, and the second electrode sheet 13 is fixed to the front side of the heater insulating layer 42. At the same time, the front side of the heater insulating layer 42 is also fixed to the exposed surface on the back side of the insulator sheet 11 of the electrostatic sheet 10.

[0095] Next, the rear surface of the heater sheet 40 is heated and softened, and the mounting surface of the base material 20 is pressed against the rear surface of the heater sheet 40 (heating and pressing process). This causes the heater insulating layer 42 to fuse to itself, thereby fixing the mounting surface of the base material 20 to the heater insulating layer 42. In this manner, the transducer 3 is manufactured.

[0096] (7-3. Effect of transducer 6 in the sixth example) Since the transducer 6 has a heater function, it can apply heat to the subject in addition to detecting the subject's condition and applying vibration to the subject. In particular, by setting the thermal conductivity of the insulator sheet 11 and the heater insulating layer 42 as described above, the heat of the heater wire 41 can be transferred to the surface of the electrostatic sheet 10. Furthermore, by having the insulator sheet 11 and the heater insulating layer 42 contain a flame-retardant filler, the heat resistance effect can be improved.

[0097] Furthermore, when power is supplied to the heater wire 41, the heater wire 41 may become a noise source. However, the second through holes 13a of the second electrode sheet 13 have a smaller opening ratio than the first through holes 12a of the first electrode sheet 12. Therefore, the second electrode sheet 13 exhibits a high shielding function for the heater wire 41. In other words, even if noise is generated by the power supplied to the heater wire 41, the second electrode sheet 13 can exhibit the shielding function. As a result, the transducer 6 can achieve good detection accuracy as a sensor and good operating accuracy as an actuator.

[0098] (8. Applicable subjects of electrostatic transducer units) An electrostatic transducer unit (hereinafter referred to as a "transducer unit") is a member having a center line. A member having a center line includes a member (rod-shaped) having a linear center line, a member having a curved center line, and the like. The cross section (cross section perpendicular to the axis) of the member can be any shape, such as a circle, an ellipse, or a polygon. The member also includes a member having both ends, and an endless member such as a ring or frame. For example, a joystick, an armrest, a doorknob, a shift lever, a door trim, and a center trim are examples of members having both ends. The grip part of a steering wheel is also an example of an endless member. Note that when the grip part of a steering wheel is arc-shaped, such as a C-shape, it can also be cited as an example of a member having both ends.

[0099] (9. Example of transducer unit 100) As an example of the transducer unit 100, a steering wheel 200 will be described with reference to Fig. 13. The steering wheel 200 is, for example, a steering wheel having a sensor function capable of detecting contact with the driver's hands. The steering wheel 200 may also have an actuator function that applies vibrations or the like to the driver's hands.

[0100] 13, steering wheel 200 includes a core portion 201 located at the center, a ring-shaped grip portion 202, and a plurality of connecting portions 203, 204, and 205 that connect core portion 201 and grip portion 202. Grip portion 202 is a portion that a driver grips to steer the wheel. Grip portion 202 functions as a sensor for detecting contact with the driver's hand.

[0101] In this example, the grip portion 202 has a sensor function over almost the entire circumference. For example, the grip portion 202 can detect contact in each of two areas, the front surface and the back surface. That is, the grip portion 202 includes a transducer 112a arranged on the front surface and a transducer 112b arranged on the back surface.

[0102] (10. First Example Transducer Unit 110) The configuration of a first example of a transducer unit 110 will be described with reference to Figures 13 and 14. In particular, as an example of the transducer unit 110, the detailed configuration of a grip portion 202 of a steering wheel 200 will be described.

[0103] The gripping portion 202 of the steering wheel 200 includes a core material 111 having a center line, transducers 112a and 112b, a resin inner layer material 113, and an outer skin material 114. The front shape of the core material 111 is formed, for example, in a ring shape. That is, the core material 111 is a member having a ring-shaped center line. The core material 111 is formed of a metal having electrical conductivity, such as aluminum. The core material 111 is connected, for example, to a ground potential. The core material 111 is connected to connecting portions 203, 204, and 205 shown in FIG. 13. The cross-sectional shape of the core material 111 perpendicular to the axis is, for example, U-shaped, but may be any shape, such as a circle, an ellipse, or a polygon. The core material 111 may be formed of a non-conductive resin.

[0104] The transducers 112a and 112b are any of the above-mentioned transducers 1, 2, 3, 4, and 5. In FIG. 14, the front transducer 112a is arranged on the upper side of the figure, and the back transducer 112b is arranged on the lower side of the figure. In FIG. 14, the transducers 112a and 112b are illustrated as including an insulating sheet 11, a first electrode sheet 12, and a second electrode sheet 13. For example, the first electrode sheet 12 functions as a sensor electrode, and the second electrode sheet 13 functions as a shield electrode.

[0105] The transducers 112a and 112b are disposed facing each other at a distance from the outer surface of the core material 111. That is, as shown in Fig. 14, the transducers 112a and 112b are disposed along the outer circumferential surface of the core material 111 so as to face the outer circumferential surface centered on the center line of the core material 111. Furthermore, the transducers 112a and 112b are disposed along the circumferential direction of the ring-shaped core material 111.

[0106] Here, the second electrode sheet 13 constituting the transducers 112a and 112b is disposed on the core material 111 side. That is, the second electrode sheet 13 is disposed along the outer peripheral surface of the core material 111 and along the circumferential direction of the core material 111 so that the back surface of the second electrode sheet 13 faces the outer peripheral surface centered on the center line of the core material 111. That is, the back surface of the second electrode sheet 13 constitutes the back surface of the transducers 112 and 112b.

[0107] Here, as shown in Fig. 14, the end sides in the circumferential direction of the outer circumferential surface of core material 111 in transducers 112a and 112b are defined as first end sides 112a1 and 112b1. Also, as shown in Fig. 13, the end sides in the circumferential direction of the ring-shaped core material 111 in transducers 112a and 112b are defined as second end sides 112a2 and 112b2.

[0108] Two first end sides 112a1, 112b1 of transducers 112a, 112b are disposed opposite each other at a distance in the circumferential direction of the outer circumferential surface of core material 111. For example, in FIG. 14, a first end side 112a1 of transducer 112a and a first end side 112b1 of transducer 112b are disposed opposite each other at a distance in the circumferential direction of the outer circumferential surface of core material 111.

[0109] Further, two second end sides 112a2, 112b2 of the transducers 112a, 112b are disposed opposite to each other at a distance in the circumferential direction of the ring-shaped core material 111. For example, in FIG. 13, a second end side 112a2 of the transducer 112a and a second end side 112b2 of the transducer 112b are disposed opposite to each other at a distance in the circumferential direction of the ring-shaped core material 111.

[0110] The resin inner layer material 113 is interposed between the outer peripheral surface of the core material 111 and the rear surfaces of the transducers 112a and 112b, and is fixed to the core material 111 and the transducers 112a and 112b. The resin inner layer material 113 is formed by injection molding. By using the core material 111 and the transducers 112a and 112b as inserts in a mold, the resin inner layer material 113 is fixed to the core material 111 and the transducers 112a and 112b at the time when the injection molding is completed. The resin inner layer material 113 is formed from a foamed resin such as urethane foam. Note that the resin inner layer material 113 may also be made of a non-foamed resin.

[0111] Furthermore, the resin inner layer material 113 is interposed in the gap between two first end sides 112a1, 112b1 that are arranged opposite each other in the circumferential direction of the outer circumferential surface of the core material 111. The resin inner layer material 113 is also interposed in the gap between two second end sides 112a2, 112b2 that are arranged opposite each other in the circumferential direction of the ring-shaped core material 111.

[0112] The surfaces of the transducers 112a and 112b are covered with the outer cover material 114. The outer cover material 114 may be formed by injection molding using resin, or leather may be used.

[0113] When the transducers 112a and 112b are disposed along the outer circumferential surface of the core material 111, the resin inner layer material 113 is disposed between the outer circumferential surface of the core material 111 and the rear surfaces of the transducers 112a and 112b, and the resin inner layer material 113 is fixed to the outer circumferential surface of the core material 111 and the rear surfaces of the transducers 112a and 112b. Therefore, the transducers 112a and 112b can be prevented from peeling off from the core material 111.

[0114] Furthermore, by interposing the resin inner layer material 113 in the gap between the two opposing ends (the first end and the second end) of the transducers 112a and 112b, the design of the transducer unit 110 is improved. Furthermore, by using the resin inner layer material 113, the transducer unit 110 can be easily manufactured.

[0115] Here, in the case where the transducers 112a and 112b are configured to include the heater sheet 40 like the transducer 6 of the sixth example described above, the resin inner layer material 113 is fixed to the heater sheet 40.

[0116] (11. Second Example Transducer Unit 120) The configuration of the transducer unit 120 of the second example will be described with reference to Figures 15 and 16. As an example of the transducer unit 120, similar to the first example, the detailed configuration of the grip portion 202 of the steering wheel 200 will be described. In addition, in the transducer unit 120 of the second example, the same components as those in the first example are denoted by the same reference numerals and will not be described.

[0117] 15, the transducers 112a and 112b include first terminal portions 112a3 and 112b3 electrically connected to the first electrode sheet 12. The first terminal portions 112a3 and 112b3 are formed in the same manner as the first electrode sheet 12, and protrude from the long sides of the first electrode sheet 12.

[0118] 15, the transducers 112a and 112b include second terminal portions 112a4 and 112b4 electrically connected to the second electrode sheet 13. The second terminal portions 112a4 and 112b4 are formed in the same manner as the second electrode sheet 13, and protrude from the long sides of the second electrode sheet 13.

[0119] 16, at least a part of the first terminals 112a3, 112b3 and at least a part of the second terminals 112a4, 112b4 are disposed in the gap between the opposing first end sides 112a1, 112b1. The ends of the first terminals 112a3, 112b3 and the ends of the second terminals 112a4, 112b4 extend outward beyond the outer cover material 114 and are electrically connected to the first wiring 121 and the second wiring 122. The first wiring 121 and the second wiring 122 extend, for example, to the vicinity of the core portion 201 of the steering wheel 200 and are connected to a detection circuit (not shown).

[0120] That is, by arranging at least a part of the first terminals 112a3, 112b3 and at least a part of the second terminals 112a4, 112b4 in the gap between the opposing first ends 112a1, 112b1, a good design can be achieved.

[0121] At least a portion of the first terminals 112a3, 112b3 and at least a portion of the second terminals 112a4, 112b4 may be disposed in the gap between the opposing second ends 112a2, 112b2, instead of in the gap between the first ends 112a1, 112b1.

[0122] (12. Third Example Transducer Unit 130) The configuration of the transducer unit 130 of the third example will be described with reference to Fig. 17. As an example of the transducer unit 130, similar to the second example, a detailed configuration of the grip portion 202 of the steering wheel 200 will be described. In the transducer unit 130 of the third example, the same components as those in the second example will be denoted by the same reference numerals and description thereof will be omitted.

[0123] 17, the transducers 112a and 112b include a first wiring 121 electrically connected to the first electrode sheet 12. For example, one end of the first wiring 121 is connected to a long side of the first electrode sheet 12. The transducers 112a and 112b also include a second wiring 122 electrically connected to the second electrode sheet 13. One end of the second wiring 122 is connected to a long side of the second electrode sheet 13.

[0124] 17, at least a part of the first wiring 121 and at least a part of the second wiring 122 are disposed in the gap between the opposing first end sides 112a1, 112b1. The other end of the first wiring 121 and the other end of the second wiring 122 extend outward from the outer cover material 114, for example, to the vicinity of the core portion 201 of the steering wheel 200, and are connected to a detection circuit (not shown). In other words, by disposing at least a part of the first wiring 121 and at least a part of the second wiring 122 in the gap between the opposing first end sides 112a1, 112b1, it is possible to improve the design.

[0125] Furthermore, at least a portion of the first wiring 121 and at least a portion of the second wiring 122 may be disposed in the gap between the opposing second end sides 112a2 and 112b2, instead of in the gap between the first end sides 112a1 and 112b1.

[0126] (13. Fourth Example of Transducer Unit 140 and Manufacturing Method) The configuration and manufacturing method of the transducer unit 140 of the fourth example will be described with reference to Figures 18 to 25. As an example of the transducer unit 130, the detailed configuration of the grip portion 202 of the steering wheel 200 will be described in the same manner as in the second example. In the transducer unit 130 of the third example, the same components as those in the second example will be denoted by the same reference numerals and will not be described.

[0127] The transducer 112 shown in FIG. 19 is formed into a sheet (step S1). The transducer 112 is a sheet in which the two transducers 112a and 112b shown in FIG. 15 are integrated. That is, the portions of the insulator sheet 11 of the two transducers 112a and 112b are integrated. The transducer 112 also has first terminal portions 112a3 and 112b3 and second terminal portions 112a4 and 112b4. The sheet-like transducer 112 has a first end side 112f which is a short side, and a second end side 112g which is a long side.

[0128] Furthermore, the transducer 112 has a third through hole 112e penetrating in the thickness direction in an area where the first electrode sheet 12 and the second electrode sheet 13 are not disposed. In this example, two third through holes 112e are formed between the transducers 112a and 112b.

[0129] Next, the sheet-like transducer 112 is preliminarily molded into a cylindrical ring shape (step S2) as shown in Fig. 20. The preliminarily molded transducer 112 is molded so that two first end sides 112f face each other in the circumferential direction of the ring shape. In Fig. 20, the facing parts are located on the lower side.

[0130] 21, the preformed transducer 112 is formed such that two second end sides 112g face each other on the outer circumferential surface centered on the center line of the cylinder. As shown in FIGS. 20 and 21, the two facing second end sides 112g are located on the side facing the center of the ring shape.

[0131] Next, as shown in FIG. 22, the core material 111 and the transducer 112 pre-molded into a ring shape are set in the mold 300 (step S3). Next, as shown in FIG. 22, the resin inner layer material 113 is molded by injection molding (step S4). At this time, the third through hole 112e functions as a resin injection hole for injection molding, and the gap of the opposing first end side 112f or the gap of the opposing second end side 112g functions as an air vent hole during resin injection. In addition, the gap of the opposing first end side 112f or the gap of the opposing second end side 112g may function as a resin injection hole for injection molding, and the third through hole 112e may function as an air vent hole during resin injection. Then, the resin inner layer material 113 is arranged in the gap of the opposing first end side 112f, the gap of the opposing second end side 112g, and the third through hole 112e.

[0132] Then, as shown in Fig. 24, the metal mold 300 is removed to form the core material 111, the transducer 112, and the resin inner layer material 113. Next, as shown in Fig. 25, the outer cover material 114 is molded by injection molding or the like (step S5). In this manner, the steering wheel 200 is completed as the transducer unit 140. The transducer unit 140 manufactured as described above is easy to manufacture and has a good design.

[0133] Here, in the above, the first terminals 112a3-112d3 and the second terminals 112a4-112d4 are arranged in the gap between the opposing second end sides 112g. However, in addition to this, the first terminals 112a3-112d3 and the second terminals 112a4-112d4 may be arranged in the gap between the opposing first end sides 112f. Furthermore, the first terminals 112a3-112d3 and the second terminals 112a4-112d4 may be arranged in the third through hole 112e.

[0134] 17, in the case where the transducer 112 does not have the first terminal portions 112a3-112d3 and the second terminal portions 112a4-112d4, but has the first wiring 121 and the second wiring 122, the first wiring 121 and the second wiring 122 may be arranged in the gap between the opposing second end sides 112g. Also, the first wiring 121 and the second wiring 122 may be arranged in the gap between the opposing first end sides 112f. Alternatively, the first wiring 121 and the second wiring 122 may be arranged in the third through hole 112e.

[0135] (14. Others) In the above first to fourth examples of transducer units 110, 120, 130, and 140, transducer 112a is arranged on the front surface and transducer 112b is arranged on the rear surface, but multiple transducers may be arranged on either or both of the front surface and the rear surface.

[0136] In this case, a resin inner layer material can be interposed in the gap between the second end sides of adjacent transducers arranged opposite each other in the circumferential direction of the ring. In this case, the plurality of transducers may each have a first terminal portion and a second terminal portion at a middle position in the circumferential direction of the ring. Also, the plurality of transducers may each have a first terminal portion and a second terminal portion at the second end sides facing each other in the circumferential direction of the ring.

[0137] In addition, in the transducer units 110, 120, 130, and 140 of the first to fourth examples described above, the following transducers can be applied instead of the transducers 1 to 6 of the first to sixth examples described above. Transducers to which the present invention can be applied include, for example, transducers including a first electrode sheet 12 and a second electrode sheet 13 having the same aperture ratio and aperture area of ​​the through holes 12a and 13a, and transducers including a first electrode sheet 12 and a second electrode sheet 13 having no through holes 12a and 13a. In the transducers to which the present invention can be applied, the configurations other than the first electrode sheet 12 and the second electrode sheet 13 are similar. [Explanation of symbols]

[0138] 1,2,3,4,5,6: electrostatic transducer, 10: electrostatic sheet, 11: insulating sheet, 11a: first coating layer, 11b: second coating layer, 12,14,16,17,18: first electrode sheet, 12a,14a,16a,16b,17a,18a: first through hole, 13,15: second electrode sheet, 13a,15a: second through hole, 20: substrate, 30: substrate side fusion sheet, 40: heater sheet, 41: heater wire, 42: heater insulating layer, 42a: first material, 42b: second material, P1,P3,P5: first detection area, P2,P4,P6: second detection area, 100,110,120,130,140: transducer unit, 111: core material, 112, 112a, 112b: electrostatic transducer, 112a1, 112b1: first end, 112a2, 112b2: second end, 112a3, 112b3: first terminal portion, 112a4, 112b4: second terminal portion, 112e: third through hole, 112f: first end, 112g: second end, 113: resin inner layer material, 114: outer cover material, 121: first wiring, 122: second wiring, 200: steering wheel, 201: core portion, 202: grip portion, 203, 204, 205: connecting portion, 300: mold

Claims

1. An insulating sheet; a first electrode sheet disposed on a front surface side of the insulator sheet and having a plurality of first through holes penetrating in a thickness direction; a second electrode sheet disposed on a rear surface side of the insulator sheet and having a plurality of second through holes penetrating in a thickness direction; Equipped with an aperture ratio of the second through holes is smaller than an aperture ratio of the first through holes; The aperture ratio of the plurality of first through holes is 30% or more; The aperture ratio of the plurality of second through holes is less than 50%, An opening area of ​​each of the second through holes is smaller than an opening area of ​​each of the first through holes, An electrostatic transducer, wherein the first electrode sheet has at least two detection areas, and the at least two detection areas each have the first through holes with different opening areas.

2. An insulating sheet; a first electrode sheet disposed on a front surface side of the insulator sheet and having a plurality of first through holes penetrating in a thickness direction; a second electrode sheet disposed on a rear surface side of the insulator sheet and having a plurality of second through holes penetrating in a thickness direction; Equipped with an aperture ratio of the second through holes is smaller than an aperture ratio of the first through holes; The aperture ratio of the plurality of first through holes is 30% or more; The aperture ratio of the plurality of second through holes is less than 50%, An opening area of ​​each of the second through holes is smaller than an opening area of ​​each of the first through holes, The first electrode sheet has at least two detection regions, the at least two detection regions having different thicknesses.

3. An insulating sheet; a first electrode sheet disposed on a front surface side of the insulator sheet and having a plurality of first through holes penetrating in a thickness direction; a second electrode sheet disposed on a rear surface side of the insulator sheet and having a plurality of second through holes penetrating in a thickness direction; Equipped with an aperture ratio of the second through holes is smaller than an aperture ratio of the first through holes; The aperture ratio of the plurality of first through holes is 30% or more; The aperture ratio of the plurality of second through holes is less than 50%, An opening area of ​​each of the second through holes is smaller than an opening area of ​​each of the first through holes, The insulating sheet is made of an elastomer, the opposing surfaces of the first electrode sheet and the insulator sheet are fixed to each other by fusion of the insulator sheet itself, An electrostatic transducer, wherein the opposing surfaces of the second electrode sheet and the insulating sheet are fixed to each other by fusing the insulating sheet itself.

4. The electrostatic transducer according to claim 3 , wherein the first electrode sheet and the second electrode sheet are embedded in the insulating sheet.

5. At least a portion of the first electrode sheet is embedded in the insulator sheet; the insulator sheet includes a first coating layer formed of a part of the insulator sheet on a surface side of the first electrode sheet, 5. The electrostatic transducer according to claim 4, wherein at least a portion of a surface of the first electrode sheet is fixed to the first covering layer by fusing the first covering layer itself.

6. 6. The electrostatic transducer according to claim 3, wherein the first electrode sheet and the second electrode sheet are formed of an elastomer containing a conductive filler.

7. An insulating sheet; a first electrode sheet disposed on a front surface side of the insulator sheet and having a plurality of first through holes penetrating in a thickness direction; a second electrode sheet disposed on a rear surface side of the insulator sheet and having a plurality of second through holes penetrating in a thickness direction; Equipped with an aperture ratio of the second through holes is smaller than an aperture ratio of the first through holes; The aperture ratio of the plurality of first through holes is 30% or more; The aperture ratio of the plurality of second through holes is less than 50%, An opening area of ​​each of the second through holes is smaller than an opening area of ​​each of the first through holes, An electrostatic transducer, wherein the insulating sheet is made of a styrene-based elastomer or an olefin-based elastomer.

8. 8. The electrostatic transducer according to claim 7, wherein the first electrode sheet is made of a styrene-based elastomer or an olefin-based elastomer and has a higher softening point than the insulating sheet.

9. An insulating sheet; a first electrode sheet disposed on a front surface side of the insulator sheet and having a plurality of first through holes penetrating in a thickness direction; a second electrode sheet disposed on a rear surface side of the insulator sheet and having a plurality of second through holes penetrating in a thickness direction; An electrostatic transducer comprising: an aperture ratio of the second through holes is smaller than an aperture ratio of the first through holes; The aperture ratio of the plurality of first through holes is 30% or more; The aperture ratio of the plurality of second through holes is less than 50%, An opening area of ​​each of the second through holes is smaller than an opening area of ​​each of the first through holes, The electrostatic transducer further includes a heater sheet laminated on a rear surface side of the second electrode sheet.

10. 10. The electrostatic transducer according to claim 9, wherein the insulating sheet has a thermal conductivity of 0.3 W / m·K or more.

11. 11. The electrostatic transducer according to claim 10, wherein the insulating sheet contains a thermally conductive filler having a thermal conductivity of 5 W / m·K or more.

12. 12. The electrostatic transducer according to claim 11, wherein the thermally conductive filler is an insulating metal filler.

13. 13. The electrostatic transducer according to claim 9, wherein the insulating sheet comprises a flame-retardant filler.

14. 14. The electrostatic transducer of claim 13, wherein the flame-retardant filler is a hydroxide filler.

15. 15. The electrostatic transducer according to claim 1, wherein the diameter of the inscribed circle of the first through hole is set to be equal to or greater than 150 μm and equal to or less than 15 mm.

16. An insulating sheet; a first electrode sheet disposed on a front surface side of the insulator sheet and having a plurality of first through holes penetrating in a thickness direction; a second electrode sheet disposed on a rear surface side of the insulator sheet and having a plurality of second through holes penetrating in a thickness direction; A heater sheet laminated on the back surface side of the second electrode sheet; Equipped with an aperture ratio of the second through holes is smaller than an aperture ratio of the first through holes; An electrostatic transducer, wherein an opening area of ​​each of the second through holes is smaller than an opening area of ​​each of the first through holes.

17. A core having a centerline; 17. The electrostatic transducer according to claim 1, wherein the electrostatic transducer is disposed along an outer peripheral surface of the core material such that a rear surface of the second electrode sheet faces an outer peripheral surface centered on the center line of the core material; a resin inner layer material interposed between the outer circumferential surface of the core material and a rear surface of the electrostatic transducer and fixed to the core material and the electrostatic transducer; An electrostatic transducer unit comprising: In the electrostatic transducer, an end side in a circumferential direction of the outer circumferential surface of the core material is defined as a first end side, The two first end sides of the electrostatic transducer are disposed opposite to each other at a distance in the circumferential direction of the outer circumferential surface of the core material, The electrostatic transducer unit, wherein the resin inner layer material is interposed in the gap between the two first end sides.

18. A core having a centerline; an electrostatic transducer disposed along an outer circumferential surface of the core material so as to face the outer circumferential surface of the core material centered on the center line; a resin inner layer material interposed between the outer circumferential surface of the core material and a rear surface of the electrostatic transducer and fixed to the core material and the electrostatic transducer; An electrostatic transducer unit comprising: The electrostatic transducer is An insulating sheet; a first electrode sheet disposed on a front surface side of the insulator sheet and having a plurality of first through holes penetrating in a thickness direction; a second electrode sheet disposed on a rear surface side of the insulator sheet, the second electrode sheet having no through holes in a thickness direction or having a plurality of second through holes having an aperture ratio smaller than that of the plurality of first through holes; the electrostatic transducer is disposed along an outer circumferential surface of the core material such that a rear surface of the second electrode sheet faces an outer circumferential surface of the core material centered on the center line of the core material; In the electrostatic transducer, an end side in a circumferential direction of the outer circumferential surface of the core material is defined as a first end side, The two first end sides of the electrostatic transducer are disposed opposite to each other at a distance in the circumferential direction of the outer circumferential surface of the core material, The electrostatic transducer unit, wherein the resin inner layer material is interposed in the gap between the two first end sides.

19. the electrostatic transducer has a first terminal portion or a first wiring electrically connected to the first electrode sheet, 19. The electrostatic transducer unit according to claim 17, wherein the first terminal portion or the first wiring is disposed in a gap between the two first end sides that are disposed opposite to each other.

20. the electrostatic transducer has at least one third through hole penetrating in a thickness direction in a region where the first electrode sheet and the second electrode sheet are not disposed and functioning as a resin injection hole or an air vent hole during resin injection, The electrostatic transducer unit according to any one of claims 17 to 19, wherein the resin inner layer material is disposed in the third through hole.

21. the electrostatic transducer has a first terminal portion or a first wiring electrically connected to the first electrode sheet, The electrostatic transducer unit according to claim 20 , wherein the first terminal portion or the first wiring is disposed in the third through hole.

22. The core material has a shape in which the center line is formed in a ring shape, In the electrostatic transducer, an end edge of the core material in the circumferential direction of the ring shape is defined as a second end edge, The two second end sides of the electrostatic transducer are disposed opposite to each other at a distance in the circumferential direction of the ring-shaped core material, The electrostatic transducer unit according to any one of claims 17 to 21, wherein the resin inner layer material is interposed in a gap between the two second end sides.

23. the electrostatic transducer has a first terminal portion or a first wiring electrically connected to the first electrode sheet, The electrostatic transducer unit according to claim 22 , wherein the first terminal portion or the first wiring is disposed in a gap between the two second end sides that are disposed opposite to each other.

24. The electrostatic transducer further includes a heater sheet disposed on a rear surface side of the second electrode sheet, The electrostatic transducer unit according to any one of claims 17 to 23, wherein the resin inner layer material is fixed to the heater sheet.

25. the electrostatic transducer has a second terminal portion or a second wiring electrically connected to the second electrode sheet, The electrostatic transducer unit according to any one of claims 17 to 24, wherein the second terminal portion or the second wiring is arranged in a gap between the two first end sides arranged opposite each other.

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