Electrostatic transducer

Abstract

The electrostatic transducer (1) comprises: an insulator sheet (11); a first electrode sheet (12); a lead wire (30); a first bonding portion (61) electrically bonding the first electrode sheet (12) and the core wire (30a) of the lead wire (30) in a first region (Pa) where the first electrode sheet (12) and the core wire (30a) of the lead wire (30) overlap; and a second bonding portion (62) bonding the insulator sheet (11) and the covering portion (30b) of the lead wire (30) in a second region (Pb) where the insulator sheet (11) and the covering portion (30b) of the lead wire (30) overlap.

Description

Technical Field

[0001] The present invention relates to electrostatic transducers. Background Art

[0002] Patent Document 1 describes exposing the core wire of a lead (synonymous with a wire), connecting the core wire to an electrode pad on a substrate by ultrasonic bonding, and then fixing the lead wire to the substrate with a bonding resin. Patent Document 2 describes connecting the exposed core wire to a connection pad via a metal tube by ultrasonic bonding.

[0003] Patent Document 3 describes ultrasonic bonding of the lead wire core wire to the terminal electrode without removing the insulating coating from the lead wire end. Patent Document 4 describes a spiral flat coil formed on the surface of a thermoplastic film. The flat coil is formed by fusing a lead wire (conducting wire) covered with a thermoplastic resin to the film surface, thereby spiraling in approximately the same direction and having a substantially uniform shape.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 6511271

[0007] Patent Document 2: Japanese Patent No. 6464321

[0008] Patent Document 3: Japanese Patent No. 4844848

[0009] Patent Document 4: Japanese Patent Application Laid-Open No. 2009-21549 Summary of the Invention

[0010] Problems to be solved by the invention

[0011] When the lead wire's tip is attached to the electrode sheet, preventing the lead wire from being pulled out or peeled off axially from the electrode sheet is important for ensuring connection reliability. In particular, when the electrode sheet is relatively soft, the lead wire is more susceptible to being pulled out or peeled off. Furthermore, it is desirable to easily and cost-effectively connect the electrode sheet to the lead wire.

[0012] An object of the present invention is to provide an electrostatic transducer capable of reliably electrically bonding a core wire of a lead wire to an electrode sheet and improving the pull-out strength of the lead wire.

[0013] Means used to solve problems

[0014] One embodiment of the present invention is an electrostatic transducer,

[0015] The electrostatic transducer comprises:

[0016] Insulator sheet;

[0017] a first electrode sheet disposed on a first surface of the insulator sheet;

[0018] a lead wire including a core wire and a covering portion formed of a thermoplastic material and covering the core wire, the lead wire having a portion overlapping the first surface of the insulator sheet and a portion overlapping the first electrode sheet;

[0019] a first bonding portion electrically bonding the first electrode sheet to the core wire of the lead in a first region, the first region being a first region in a surface direction of the insulator sheet and where the first electrode sheet and the core wire of the lead are overlapped; and

[0020] A second joining portion joins the insulating sheet and the covering portion of the lead in a second region, the second region being a second region in the surface direction of the insulating sheet different from the first region and in which the insulating sheet and the covering portion of the lead are overlapped.

[0021] Effects of the Invention

[0022] According to the electrostatic transducer described above, the first joint in the first region electrically joins the first electrode sheet to the core wire of the lead, while the second joint in the second region joins the insulator sheet to the covering portion of the lead. In other words, the pull-out strength of the lead is primarily due to the second joint in the second region. This allows for both electrical joining and pull-out strength to be achieved by arranging the portion where the first electrode sheet electrically joins the core wire of the lead at a different location than the portion where the pull-out strength of the lead is ensured. Therefore, the core wire of the lead can be reliably electrically joined to the first electrode sheet, and the pull-out strength of the lead can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a cross-sectional view of the electrostatic transducer of the first example.

[0024] Figure 2 1 is a top view of the electrostatic transducer of the first example.

[0025] Figure 3 1 is a plan view of a second example of a junction restriction layer constituting the electrostatic transducer of the first example.

[0026] Figure 4 yes Figure 3 IV-IV sectional view of FIG.

[0027] Figure 5 1 is a plan view of a junction restriction layer of a third example constituting the electrostatic transducer of the first example.

[0028] Figure 6 yes Figure 5 VI-VI sectional view.

[0029] Figure 7 is a cross-sectional view of an electrostatic transducer according to a second example.

[0030] Figure 8 is a cross-sectional view of an electrostatic transducer according to a third example.

[0031] Figure 9 is a cross-sectional view of an electrostatic transducer according to a fourth example.

[0032] Figure 10 is a cross-sectional view of an electrostatic transducer according to a fifth example.

[0033] Figure 11 is a cross-sectional view of an electrostatic transducer according to a sixth example.

[0034] Figure 12 is a cross-sectional view of an electrostatic transducer according to a seventh example.

[0035] Figure 13 is a cross-sectional view of an electrostatic transducer according to an eighth example.

[0036] Figure 14 is a cross-sectional view of an electrostatic transducer according to a ninth example.

[0037] Figure 15 is a cross-sectional view of an electrostatic transducer according to a tenth example. DETAILED DESCRIPTION

[0038] (1. Applicable Targets)

[0039] An electrostatic transducer (hereinafter referred to as a "transducer") includes, for example, a substrate and an electrostatic sheet mounted on a mounting surface of the substrate. The substrate is an arbitrary member material and is formed of metal, resin, or other materials.

[0040] In addition, the mounting surface of the substrate can be formed into a three-dimensional shape such as a curved surface, a composite plane (a shape formed by multiple planes), or a composite shape of a plane and a curved surface. The surface of the substrate can also be formed into a single flat shape. In the case where the substrate is formed of a flexible material, the electrostatic sheet can also be mounted on the mounting surface of the substrate. In addition, the transducer can also be used as a single electrostatic sheet without a substrate.

[0041] The electrostatic sheet is disposed on the mounting surface (surface) of the substrate. The electrostatic sheet is relatively soft overall. Softness means that it is flexible and can be stretched in the surface direction. Therefore, even if the mounting surface of the substrate is a three-dimensional shape, the electrostatic sheet can be mounted along the mounting surface of the substrate. In particular, by stretching the electrostatic sheet in the surface direction while mounting it on the mounting surface of the substrate, wrinkles in the electrostatic sheet can be suppressed.

[0042] An electrostatic sheet can function as an actuator or sensor by utilizing changes in the electrostatic capacitance between a pair of electrodes. An electrostatic sheet is sufficient as long as it includes at least one of the pair of electrodes, and is not limited to structures having only one pair of electrodes. Of course, an electrostatic sheet can also include a pair of electrodes. Furthermore, in an electrostatic sheet, the electrode on the back side can function as a shielding electrode.

[0043] Electrostatic sheets can function as actuators that generate vibrations, sounds, etc. by utilizing changes in electrostatic capacitance between electrodes. Furthermore, electrostatic sheets can function as sensors that detect external pressure, etc., by utilizing changes in electrostatic capacitance between electrodes, or as sensors that detect the contact or proximity of a conductive body with a potential.

[0044] When the electrostatic sheet functions as an actuator, by applying a voltage to the electrodes, the potential between the insulator and the electrodes is deformed accordingly, and vibration is generated along with the deformation of the insulator. When the electrostatic sheet functions as a sensor for detecting pressing force, the insulator is deformed due to input from external pressing force, vibration, and sound, etc. (hereinafter referred to as external pressing force, etc.), thereby changing the electrostatic capacitance between the electrodes. The external pressing force, etc. is detected by detecting the voltage corresponding to the electrostatic capacitance between the electrodes. In addition, when the electrostatic sheet functions as a sensor for detecting contact or proximity, the electrostatic capacitance between the electrodes changes due to the contact or proximity of a conductor with a potential. The contact or proximity of the conductor is detected by detecting the voltage corresponding to the changed electrostatic capacitance between the electrodes.

[0045] Transducers can be applied to surfaces such as pointing devices like mice and joysticks, and vehicle parts. Examples of vehicle parts include armrests, door handles, gearshifts, steering wheels, door trims, center consoles, and roofs. In most cases, the substrate is made of an inflexible material such as metal or rigid resin. Furthermore, transducers can detect the subject's condition and impart vibrations to the subject.

[0046] Alternatively, the transducer may be positioned on the surface of the seat surface or the backrest. In this case, the transducer may be constructed by attaching an electrostatic sheet to a substrate formed of a flexible material such as a resin film. Furthermore, the transducer may be constructed solely of the electrostatic sheet without a substrate.

[0047] Alternatively, the electrostatic sheet of the transducer may be configured to have a heating function. In this case, the transducer can provide heat to the subject in addition to detecting the subject's state and applying vibrations to the subject.

[0048] (2. Transducer 1a of the First Example)

[0049] Reference Figure 1 as well as Figure 2 A first example of a transducer 1a will be described. The transducer 1a includes an electrostatic sheet 10. The electrostatic sheet 10 may be disposed on the surface of a substrate (not shown) or may be used alone.

[0050] The electrostatic sheet 10 includes an insulating sheet 11 and a first electrode sheet 12. Figure 1 In the example, the electrostatic sheet 10 is shown as further including the second electrode sheet 13. However, the electrostatic sheet 10 may also be configured without the second electrode sheet 13. For example, when the substrate constitutes the electrode, the second electrode sheet 13 may be omitted.

[0051] The insulating sheet 11 includes a main body region 11a and a terminal region 11b. The main body region 11a is used as an actuator, sensor, etc. The terminal region 11b is a region for connecting power and electrical signals between the main body region 11a and the outside.

[0052] The insulating sheet 11 is formed, for example, from an elastomer. Therefore, the insulating sheet 11 is relatively soft. In other words, the insulating sheet 11 is flexible and can stretch in the planar direction. The insulating sheet 11 is formed, for example, from a thermoplastic material, particularly a thermoplastic elastomer. The insulating sheet 11 can be formed from the thermoplastic elastomer itself or from an elastomer obtained by heating and crosslinking the thermoplastic elastomer.

[0053] The insulator sheet 11 may also contain a rubber or resin other than a thermoplastic elastomer. For example, the inclusion of a rubber such as ethylene-propylene rubber (EPM, EPDM) improves the flexibility of the insulator sheet 11. To further enhance the flexibility of the insulator sheet 11, the insulator sheet 11 may also contain a flexibility-imparting component such as a plasticizer.

[0054] The first electrode sheet 12 is disposed on the first surface of the insulator sheet 11, that is, on the surface of the insulator sheet 11 ( Figure 1 The first electrode sheet 12 includes a first electrode body 12a disposed in the body region 11a of the insulator sheet 11 and a first electrode terminal 12b disposed in the terminal region 11b of the insulator sheet 11.

[0055] In addition, the first electrode sheet 12 is conductive. Furthermore, the first electrode sheet 12 is relatively soft. In other words, the first electrode sheet 12 is flexible and can be stretched in the surface direction. The first electrode sheet 12 is formed of, for example, conductive cloth, conductive elastomer, metal foil, etc. Figure 1 , the case where the first electrode sheet 12 is a conductive cloth is shown.

[0056] The case where the first electrode sheet 12 is formed from conductive cloth will be described in detail. Conductive cloth refers to a woven or nonwoven fabric made of conductive fibers. Here, conductive fibers are formed by coating the surface of flexible fibers with a conductive material. For example, conductive fibers are formed by plating copper, nickel, or the like onto the surface of resin fibers such as polyethylene.

[0057] In this case, the first electrode sheet 12 is fixed to the insulator sheet 11 by welding (thermal welding) the insulator sheet 11 itself. Since the first electrode sheet 12 is made of cloth, it has multiple through-holes. Therefore, a portion of the insulator sheet 11 enters the through-holes of the first electrode sheet 12. In other words, at least a portion of the first electrode sheet 12 is embedded in the insulator sheet 11.

[0058] The case where the first electrode sheet 12 is formed from a conductive elastomer will be described in detail. In this case, the first electrode sheet 12 is formed from an elastomer containing a conductive filler. In other words, the first electrode sheet 12 is formed by using an elastomer as a base material and incorporating a conductive filler. The elastomer used for the first electrode sheet 12 is preferably formed from the same material as the main component of the insulator sheet 11. In particular, the first electrode sheet 12 is preferably formed from a thermoplastic elastomer.

[0059] However, the first electrode sheet 12 is formed of a material having a higher softening point than the insulator sheet 11. This is because when the first electrode sheet 12 is fixed to the insulator sheet 11 by welding (thermal welding) the insulator sheet 11 itself, the insulator sheet 11 can soften before the first electrode sheet 12.

[0060] Here, the first electrode sheet 12 is fixed to the insulator sheet 11 by welding (thermal welding) the insulator sheet 11 itself. Furthermore, when the first electrode sheet 12 is formed of an elastomer, the first electrode sheet 12 and the insulator sheet 11 are fixed by welding (thermal welding) the first electrode sheet 12 itself. In other words, the first electrode sheet 12 and the insulator sheet 11 are fixed by mutual welding. Alternatively, the first electrode sheet 12 and the insulator sheet 11 may be fixed by welding only one side.

[0061] The case where the first electrode sheet 12 is formed of metal foil will be described in detail. The metal foil preferably has multiple through-holes, similar to the conductive cloth. Therefore, the first electrode sheet 12 is flexible and can be stretched in the surface direction as the through-holes deform. The metal foil can be any metal material that can conduct electricity, for example, copper foil, aluminum foil, etc. can be used. Furthermore, the first electrode sheet 12 is fixed to the insulator sheet 11 by welding (thermal welding) the insulator sheet 11 itself, similar to the case where it is conductive cloth.

[0062] The second electrode sheet 13 is disposed on the second surface of the insulator sheet 11, that is, the back surface of the insulator sheet 11 ( Figure 1 (lower surface) side. Assuming that the transducer 1a includes a substrate, the second electrode sheet 13 is disposed between the insulator sheet 11 and the substrate. The second electrode sheet 13 includes a second electrode body 13a disposed in the body region 11a of the insulator sheet 11, and a second electrode terminal 13b disposed in the terminal region 11b of the insulator sheet 11.

[0063] Here, if Figure 2 As shown, the second electrode body 13a is arranged to face substantially the entire surface of the first electrode body 12a of the first electrode sheet 12. Meanwhile, the second electrode terminal 13b of the second electrode sheet 13 is not positioned opposite the first electrode terminal 12b of the first electrode sheet 12, but is positioned offset from the first electrode terminal 12b. This is to reduce the thickness of the transducer 1a, which is associated with the presence of the leads 30 and 50 described later. However, the first electrode terminal 12b and the second electrode terminal 13b may also be arranged to face each other.

[0064] The second electrode sheet 13 is formed in the same manner as the first electrode sheet 12. In other words, the second electrode sheet 13 is relatively flexible and is formed of conductive cloth, conductive elastic body, metal foil, or the like.

[0065] The transducer 1a includes a first bonding restriction layer 20, a first lead 30, a second bonding restriction layer 40, and a second lead 50. However, in a configuration where the transducer 1a does not include the second electrode sheet 13, the transducer 1a does not include the second bonding restriction layer 40 and the second lead 50.

[0066] The first bonding restriction layer 20 is disposed between the terminal region 11b of the insulator sheet 11 and the first electrode terminal 12b of the first electrode sheet 12, restricting the bonding between the insulator sheet 11 and the first electrode sheet 12. Therefore, in the region of the first electrode terminal 12b of the first electrode sheet 12 where the first bonding restriction layer 20 is present, a space is formed between the first electrode sheet 12 and the first bonding restriction layer 20. On the other hand, in the region of the first electrode terminal 12b of the first electrode sheet 12 where the first bonding restriction layer 20 is not present, the first electrode sheet 12 and the insulator sheet 11 are bonded.

[0067] The first joint limiting layer 20 is bonded to the insulating sheet 11 by welding the insulating sheet 11 itself. Therefore, the first joint limiting layer 20 is formed of, for example, a material having a higher softening point than the insulating sheet 11. For example, a resin sheet formed of a thermoplastic material can be used as the first joint limiting layer 20.

[0068] like Figure 2As shown, the first bonding restriction layer 20 is formed into a long strip. One end of the first bonding restriction layer 20 in the longitudinal direction is arranged at the end edge of the first electrode terminal 12b of the first electrode sheet 12. The other end of the first bonding restriction layer 20 in the longitudinal direction is arranged to extend from the end edge of the first electrode terminal 12b of the first electrode sheet 12 toward the first electrode body 12a of the first electrode sheet 12. In this example, the other end of the first bonding restriction layer 20 in the longitudinal direction is arranged to extend in a direction intersecting the end edge of the first electrode sheet 12, particularly in an oblique direction.

[0069] The first joint restriction layer 20 includes a narrow inner portion 21 and a wide edge portion 22. Figure 2 In the embodiment, the inner portion 21 is formed to have a uniform width over the entire length, and the edge portion 22 is also formed to have a uniform width over the entire length. In addition, the width may be gradually narrowed from the base end of the edge portion 22 (the end side of the first electrode sheet 12) toward the front end of the inner portion 21.

[0070] The first lead wire 30 includes a core wire 30a and a covering 30b that insulates the outer surface of the core wire 30a. The core wire 30a is formed, for example, from a copper wire. The covering 30b is formed from a thermoplastic material. The covering 30b can be made of any insulating thermoplastic material, for example, a material suitable for the insulator sheet 11 described above.

[0071] A portion of the first lead 30 is disposed on the first surface ( Figure 1 In the transducer 1a of the first example, a portion of the first lead 30 is disposed in a region where both the insulator sheet 11 and the first electrode sheet 12 exist. Therefore, the first lead 30 overlaps the first surface of the insulator sheet 11 and also overlaps the first electrode sheet 12.

[0072] Furthermore, when the first electrode sheet 12 has an area that does not overlap with a portion of the insulator sheet 11, the first lead 30 may have a portion that overlaps only the insulator sheet 11 and a portion that overlaps both the insulator sheet 11 and the first electrode sheet 12. In this case, the first lead 30 has a portion that overlaps at least the first surface of the insulator sheet 11 and a portion that overlaps the first electrode sheet 12.

[0073] In this example, the first lead 30 is disposed between the insulating sheet 11 and the first electrode sheet 12 . In particular, since the first joint restriction layer 20 is disposed on the insulating sheet 11 , the first lead 30 is disposed between the first joint restriction layer 20 and the first electrode sheet 12 .

[0074] The first lead 30 includes a core wire exposed portion 31 where the core wire 30a is exposed by removing the covering portion 30b at the distal end of the first lead 30. The first lead 30 also includes a core wire covering portion 32 where the covering portion 30b is not removed.

[0075] The exposed core wire portion 31 is preferably configured as follows. The exposed core wire portion 31 is configured to form a metal plating layer on the copper core wire 30a. In this case, the metal plating is preferably nickel plating. Alternatively, the exposed core wire portion 31 may be configured to form a solder flow layer on the core wire 30a. The metal plating layer and the solder flow layer serve to improve electrical conductivity with the first electrode sheet 12.

[0076] The core exposed portion 31 of the first lead 30 is disposed in the inner portion 21 of the first joint restriction layer 20 , and the core covered portion 32 is disposed in the edge portion 22 of the first joint restriction layer 20 .

[0077] Here, the first lead 30 is positioned by being inserted into the space formed between the first bonding restriction layer 20 and the first electrode sheet 12. The first bonding restriction layer 20 has a wide edge portion 22 and a narrower inner portion 21. Therefore, when inserting the first lead 30, the wider edge portion 22 facilitates initial insertion, while the narrower inner portion 21 allows the first lead 30 to be positioned at the desired position.

[0078] Furthermore, in the transducer 1a, in the region in the surface direction of the insulator sheet 11, the first region Pa ( Figure 2 ) is provided with a first bonding portion 61 ( Figure 1 shown).

[0079] In this example, in the first region Pa, the first electrode sheet 12 is electrically bonded to the portion of the core wire 30a within the exposed core wire portion 31 via the metal plating layer or the solder flow layer. In other words, the first bonding portion 61 is formed from a portion of the metal plating layer or the solder flow layer. In particular, the first bonding portion 61 formed from a portion of the solder flow layer allows for a planar electrical bond between the first electrode sheet 12 and the portion of the core wire 30a within the exposed core wire portion 31, ensuring good electrical continuity.

[0080] Here, a portion of the first bonding restriction layer 20 is positioned in the first region Pa. Therefore, after the first lead 30 is inserted between the first electrode sheet 12 and the first bonding restriction layer 20, ultrasonic welding is applied to the first region Pa, electrically bonding the first electrode sheet 12 to the exposed core portion 31 of the first lead 30. Furthermore, since the first electrode sheet 12 and the first lead 30 have metal surfaces, they are bonded by ultrasonic welding. Meanwhile, although the first lead 30 and the first bonding restriction layer 20 are adjacent, they are made of metal and resin, so even with ultrasonic welding, they will not fuse.

[0081] In addition, the transducer 1a has a second region Pb ( ) where the insulating sheet 11 and the core wire covering portion 32 of the first lead wire 30 overlap, among regions in the surface direction of the insulating sheet 11. Figure 2 ) is provided with a second joining portion 62 ( Figure 1 The second joint portion 62 is a region different from the first joint portion 61 .

[0082] In this example, a portion of the first joint restricting layer 20 is located in the second region Pb. Furthermore, a portion of the first joint restricting layer 20 is located between the insulator sheet 11 and the core wire covering portion 32 of the first lead 30 in the second region Pb. Therefore, in the second region Pb, the insulator sheet 11 is bonded to the first joint restricting layer 20, and the first joint restricting layer 20 is also bonded to the core wire covering portion 32 of the first lead 30. In other words, the second joint portion 62 is formed by a portion of the insulator sheet 11, a portion of the first joint restricting layer 20, and a portion of the core wire covering portion 32. Thus, the second joint portion 62 indirectly joins the insulator sheet 11 and the core wire covering portion 32 via the first joint restricting layer 20.

[0083] After the first lead 30 is inserted between the first electrode sheet 12 and the first joint restricting layer 20, ultrasonic welding is applied to the second region Pb, thereby joining the insulator sheet 11 to the first joint restricting layer 20 and, in turn, joining the first joint restricting layer 20 to the core wire covering portion 32. The ultrasonic welding process conditions in the second joint 62 differ from those in the first joint 61. While the first joint 61 is set to process conditions that allow the core wire exposed portion 31 to be welded, the second joint 62 is set to process conditions that prevent the core wire 30a of the core wire covering portion 32 from being welded.

[0084] The second joint restricting layer 40 is disposed between the terminal region 11b of the insulator sheet 11 and the second electrode terminal 13b of the second electrode sheet 13, and restricts the joint between the insulator sheet 11 and the second electrode sheet 13. The second joint restricting layer 40 is substantially similar in structure to the first joint restricting layer 20. Like the first joint restricting layer 20, the second joint restricting layer 40 includes a back portion 41 and an edge portion 42.

[0085] The second lead 50 includes a core wire 50a and a covering portion 50b that insulates and covers the outer circumference of the core wire 50a. The second lead 50 includes a core wire exposed portion 51, where the covering portion 50b is removed from the distal end of the second lead 50, exposing the core wire 50a. Furthermore, the second lead 50 includes a core wire covering portion 52, where the covering portion 50b is not removed. The second lead 50 is constructed substantially the same as the first lead 30.

[0086] Furthermore, the transducer 1a includes a first bonding portion 71 that electrically bonds the second electrode sheet 13 to the exposed core portion 51 of the second lead 50 in the first region Pc, and a second bonding portion 72 that bonds the insulator sheet 11 to the covered core portion 52 of the second lead 50 in the second region Pd. The first bonding portion 71 and the second bonding portion 72 are substantially the same as the first bonding portion 61 and the second bonding portion 62 described above. Furthermore, the first region Pc and the second region Pd are substantially the same as the first region Pa and the second region Pb described above.

[0087] (3. Effects of the Transducer 1a of the First Example)

[0088] In the transducer 1a of the first example, the first bonding portion 61 in the first region Pa electrically bonds the first electrode sheet 12 to the core wire 30a in the exposed core wire portion 31 of the first lead wire 30. Conversely, the second bonding portion 62 in the second region Pb bonds the insulator sheet 11 to the covering portion 30b in the core wire covering portion 32 of the first lead wire 30. In other words, the pull-out strength of the first lead wire 30 is primarily achieved by the second bonding portion 62 in the second region Pb.

[0089] In this way, by setting the location where the first electrode sheet 12 is electrically bonded to the core wire 30a of the first lead 30 and the location where the pull-out strength of the first lead 30 is ensured at different locations, both electrical bonding and pull-out strength can be achieved. Therefore, the core wire 30a of the first lead 30 can be reliably electrically bonded to the first electrode sheet 12, and the pull-out strength of the first lead 30 can be improved.

[0090] Furthermore, by setting different ultrasonic welding processing conditions in the first region Pa and the second region Pb, electrical bonding can be achieved in the first region Pa, while bonding with guaranteed pull-out strength can be achieved in the second region Pb.

[0091] The first lead 30 is positioned between the insulator sheet 11 and the first electrode sheet 12. In other words, with the first lead 30 inserted into the pocket formed by the insulator sheet 11 and the first electrode sheet 12, the first lead 30 is bonded to the first electrode sheet 12 and the insulator sheet 11. This makes it easy to position the first lead 30 at the desired location and ensures reliable bonding. Furthermore, the provision of the first bonding restriction layer 20 facilitates the formation of the aforementioned pocket between the insulator sheet 11 and the first electrode sheet 12.

[0092] (4. First Joint Restricting Layer 20)

[0093] (4-1. First Example of First Bonding Restriction Layer 20)

[0094] As described above, the first bonding restriction layer 20 constituting the first example of the transducer 1 a is a planar sheet and includes a back portion 21 and an edge portion 22 .

[0095] (4-2. First Junction Restricting Layer 20 of Second Example)

[0096] Reference Figure 3 as well as Figure 4 The first bonding restriction layer 20 of the second example will be described. The first bonding restriction layer 20 of the second example includes a back portion 21 and an edge portion 22. The edge portion 22 includes a sheet body 22a and a plurality of protrusions 22b. The sheet body 22a of the back portion 21 and the edge portion 22 are planar sheets, similar to the back portion 21 and the edge portion 22 of the first example.

[0097] Multiple protrusions 22b are provided on the first and second surfaces of the sheet body 22a of the edge portion 22, projecting in the direction normal to the surface. The multiple protrusions 22b provided on the first surface of the sheet body 22a engage with the covering portion 30b of the first lead 30 in the plane direction of the sheet body 22a. The multiple protrusions 22b provided on the second surface of the sheet body 22a engage with the insulator sheet 11 in the plane direction of the sheet body 22a. In other words, the second joint 62 includes the engaging portions of the protrusions 22b with the insulator sheet 11 and the engaging portions of the protrusions 22b with the covering portion 30b of the first lead 30.

[0098] Therefore, the insulator sheet 11 and the first joint restriction layer 20 have stronger bonding strength, and further, the covering portion 30b of the core wire covering portion 32 of the first lead 30 has stronger bonding strength with the first joint restriction layer 20. In other words, the pull-out strength can be further improved.

[0099] (4-3. First Junction Restricting Layer 20 of Third Example)

[0100] Reference Figure 5as well as Figure 6 The first bonding restriction layer 20 of the third example will be described. The first bonding restriction layer 20 of the third example includes a back portion 21 and an edge portion 22. The edge portion 22 includes a plurality of slits 22c penetrating therethrough.

[0101] Therefore, by passing at least one of the insulating sheet 11 and the covering portion 30b of the core wire covering portion 32 of the first lead 30 through the slit 22c, the insulating sheet 11 is directly bonded to the covering portion 30b of the first lead 30. In other words, the second bonding portion 62 is configured to include a portion in the slit 22c where the insulating sheet 11 and the covering portion 30b of the first lead 30 are directly bonded.

[0102] Therefore, by passing through slit 22c, the insulator sheet 11 and the covering portion 30b of the core wire covering portion 32 of the first lead wire 30 have a stronger bond strength. Furthermore, the portion of the insulator sheet 11 directly bonded to the covering portion 30b of the first lead wire 30 in slit 22c engages with the slit 22c, thereby further improving the pull-out strength.

[0103] (5. Transducer 1b of the Second Example)

[0104] Reference Figure 7 The transducer 1b of the second example is described. Figure 7 As shown, in the transducer 1b, the first electrode sheet 12 is arranged in the region corresponding to the first region Pa, whereas it is not arranged in the region corresponding to the second region Pb.

[0105] (6. Transducer 1c of the Third Example)

[0106] Reference Figure 8 The transducer 1c of the third example is described. Figure 8 As shown, in transducer 1c, first lead 30 does not have a portion where core wire 30a is exposed. First lead 30 includes a core wire bonding portion 33 at the distal end and a cover bonding portion 34 at the proximal end. Core wire bonding portion 33 corresponds to core wire exposed portion 31 in the above example, and cover bonding portion 34 corresponds to core wire cover 32 in the above example.

[0107] In the first joining portion 61, ultrasonic welding electrically joins the first electrode sheet 12 to the core wire 30a in the core wire joining portion 33. In other words, in the core wire joining portion 33, the covering portion 30b is ultrasonically melted, thereby joining the first electrode sheet 12 to the core wire 30a. In the second joining portion 62, ultrasonic welding joins the covering portion 30b to the insulator sheet 11 in the covering portion joining portion 34. This structure also achieves the same effect.

[0108] (7. Transducer 1d of the Fourth Example)

[0109] Reference Figure 9 The transducer 1d of the fourth example will be described. Unlike the transducer 1a of the first example, the transducer 1d of the fourth example does not have the first bonding restriction layer 20. In this case, the covering portion 30b of the core wire covering portion 32 of the first lead 30 is directly bonded to the insulator sheet 11. In this example, after the first electrode sheet 12 is bonded to the insulator sheet 11 except for the area where the first lead 30 is arranged, the first electrode sheet 12 is preferably bonded to the core wire 30a of the first lead 30 in the first area Pa, and the insulator sheet 11 is preferably bonded to the covering portion 30b of the first lead 30 in the second area Pb.

[0110] Alternatively, with the first electrode sheet 12 and the first lead 30 disposed on the first surface of the insulator sheet 11, the first electrode sheet 12 and the insulator sheet 11 may be welded together, the first electrode sheet 12 and the core wire 30a of the first lead 30 may be welded together by ultrasonic welding in the first region Pa, and the insulator sheet 11 and the covering portion 30b of the first lead 30 may be welded together by ultrasonic welding in the second region Pb. This configuration also achieves the same effect.

[0111] (8. Transducer 1e of the Fifth Example)

[0112] Reference Figure 10 The transducer 1e of the fifth example is described. Figure 10 As shown, the fifth example transducer 1e differs from the fourth example transducer 1d in that the first electrode sheet 12 is disposed in the region corresponding to the first area Pa, but is not disposed in the region corresponding to the second area Pb. This structure also produces the same effect.

[0113] (9. Transducer 1f of the Sixth Example)

[0114] Reference Figure 11 A sixth example transducer 1f will be described. In this sixth example transducer 1f, a first electrode sheet 12 is disposed on a first surface of an insulator sheet 11, and a first lead 30 is disposed on a surface of the first electrode sheet 12 opposite to the insulator sheet 11. In other words, the first electrode sheet 12 is disposed between the insulator sheet 11 and the first lead 30.

[0115] In this example, the core wire 30a of the exposed core wire portion 31 of the first lead wire 30 is bonded to the first electrode sheet 12 in the first region Pa, forming a first bonded portion 61. In the second region Pb, the covering portion 30b of the core wire covering portion 32 of the first lead wire 30 is bonded to the insulator sheet 11, forming a second bonded portion 62. Here, the covering portion 30b of the core wire covering portion 32 of the first lead wire 30 is bonded via a through-hole in the first electrode sheet 12. This case also achieves the same effect.

[0116] (10. Transducer 1g of the seventh example)

[0117] Reference Figure 12 The seventh example transducer 1g will be described. Compared to the sixth example transducer 1f, the seventh example transducer 1g has the first electrode sheet 12 disposed in the region corresponding to the first area Pa, but not in the region corresponding to the second area Pb. This structure also produces the same effects.

[0118] (11. Transducer 1h of the eighth example)

[0119] Reference Figure 13 The eighth example transducer 1h will now be described. Compared to the seventh example transducer 1g, the eighth example transducer 1h includes a bonding auxiliary layer 80 between the insulator sheet 11 and the covering portion 30b of the core wire covering portion 32 of the first lead 30 in the second region Pb. The bonding auxiliary layer 80 is formed of a thermoplastic material and has the function of adjusting the height difference of the first electrode sheet 12. If the bonding auxiliary layer 80 were not present, the first lead 30 might be buried in the insulator sheet 11 due to ultrasonic welding in the second region Pb. However, the presence of the bonding auxiliary layer 80 allows the height of the first lead 30 to be adjusted in the first region Pa and the second region Pb. Consequently, the bonding state of the first lead 30 can be stabilized.

[0120] (12. Transducer 1i of the Ninth Example)

[0121] Reference Figure 14 A ninth example of the transducer 1 i will be described. In the ninth example of the transducer 1 i , the first lead wire 30 includes a distal end covering portion 35 covered by a covering portion 30 b on the distal end side of the core wire exposed portion 31 .

[0122] In the first region Pa, the exposed core portion 31 is bonded to the first electrode sheet 12, forming a first bond 61. In the second region Pb, the front cover 35 is bonded to the insulator sheet 11, forming a second bond 62. This structure also achieves the same effect. Furthermore, in this example, the cover 30b of the first lead 30, which is located closer to the base end than the exposed core portion 31, can also be bonded to the insulator sheet 11 to form a second bond 62. In this case, two second bonds 62 are formed.

[0123] (13. Transducer 1j of the Tenth Example)

[0124] Reference Figure 15The transducer 1j of the tenth example will be described. Compared to the transducer 1h of the eighth example, the transducer 1j of the tenth example has a first electrode sheet 12 having multiple through-holes and formed of a thermoplastic elastomer containing a conductive filler. The second electrode sheet 13 is formed of a conductive cloth.

[0125] The through-holes in the first electrode sheet 12 are larger than the through-holes in the second electrode sheet 13. Therefore, the resistivity of the second electrode sheet 13 is lower than that of the first electrode sheet 12. Since the second electrode sheet 13 functions as a shielding electrode, its low resistivity improves shielding performance. On the other hand, the increased resistivity of the first electrode sheet 12 can reduce electrostatic capacitance.

[0126] Here, the first electrode sheet 12 is formed of a thermoplastic elastomer having through-holes, thereby easily forming an electrode sheet with a high resistivity. In addition, the second electrode sheet 13 can also be formed of a thermoplastic elastomer containing a conductive filler and formed into a shape with a through-hole area smaller than that of the first electrode sheet 12.

[0127] Furthermore, in the transducer 1j of the tenth example, the bonding auxiliary layer 101 is disposed between the cover portion 30b of the first lead 30 and the insulating sheet 11, and the bonding auxiliary layer 102 is disposed between the cover portion 50b of the second lead 50 and the insulating sheet 11. The bonding auxiliary layers 101 and 102 have the same function as the bonding auxiliary layer 80 in the transducer 1h of the eighth example.

Claims

1. An electrostatic transducer (1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i, 1j), wherein: The electrostatic transducers (1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i, 1j) include: Insulator sheet (11); a first electrode sheet (12) disposed on a first surface of the insulator sheet (11); A lead wire (30) comprising a core wire (30a) and a covering portion (30b) formed of a thermoplastic material and covering the core wire (30a), and having a portion overlapping the first surface of the insulator sheet (11) and a portion overlapping the first electrode sheet (12); a first bonding portion (61) electrically bonding the first electrode sheet (12) and the core wire (30a) of the lead wire (30) in a first region (Pa), the first region (Pa) being the first region (Pa) in the surface direction of the insulator sheet (11) and in which the first electrode sheet (12) and the core wire (30a) of the lead wire (30) are overlapped; and A second joining portion (62) joins the insulating sheet (11) and the covering portion (30b) of the lead (30) in a second region (Pb), wherein the second region (Pb) is a second region (Pb) different from the first region (Pa) in the surface direction of the insulating sheet (11) and the insulating sheet (11) and the covering portion (30b) of the lead (30) are arranged in an overlapping manner.

2. The electrostatic transducer (1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i, 1j) according to claim 1, wherein The insulator sheet (11) is formed of a thermoplastic material, The second joint portion (62) is formed by a portion of the insulator sheet (11).

3. The electrostatic transducer (1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i, 1j) according to claim 2, wherein: The insulator sheet (11) is formed of a thermoplastic elastomer.

4. The electrostatic transducer (1a, 1b, 1d, 1e, 1f, 1g, 1h, 1i, 1j) according to any one of claims 1 to 3, wherein: The lead wire (30) includes a core wire exposed portion (31) formed by removing the covering portion (30b) at the front end side of the lead wire (30) to expose the core wire (30a). The first bonding portion (61) electrically bonds the first electrode sheet (12) to the core wire exposed portion (31) of the lead wire (30).

5. The electrostatic transducer (1a, 1b, 1d, 1e, 1f, 1g, 1h, 1i, 1j) according to claim 4, wherein The core wire exposed portion (31) is provided with a metal plating layer on the core wire (30a). The first joint portion (61) is formed by a portion of the metal plating layer.

6. The electrostatic transducer (1a, 1b, 1d, 1e, 1f, 1g, 1h, 1i, 1j) according to claim 5, wherein The core wire (30a) is a copper wire, The metal plating layer is nickel plating.

7. The electrostatic transducer (1a, 1b, 1d, 1e, 1f, 1g, 1h, 1i, 1j) according to claim 4, wherein The core wire exposed portion (31) forms a solder flow layer on the core wire (30a), The first joint portion (61) is formed by a portion of the solder flow layer.

8. The electrostatic transducer (1a, 1b, 1c) according to any one of claims 1 to 3, wherein: The electrostatic transducer (1a, 1b, 1c) further includes a bonding restriction layer (20), which is arranged between the insulating sheet (11) and the first electrode sheet (12) in the first region (Pa) to restrict bonding between the insulating sheet (11) and the first electrode sheet (12).

9. The electrostatic transducer (1a, 1b, 1c) according to claim 8, wherein: A portion of the joint restriction layer (20) is arranged between the insulating sheet (11) and the covering portion (30b) of the lead (30) in the second region (Pb), The second joint portion (62) is composed of the portion of the joint restriction layer (20), a portion of the insulating sheet (11), and a portion of the covering portion (30b) of the lead (30).

10. The electrostatic transducer (1a, 1b, 1c) according to claim 9, wherein: The bonding restriction layer (20) comprises: a sheet body (22a); and A plurality of protrusions (22b) are provided on the first surface of the sheet body (22a) and engage with the covering portion (30b) of the lead (30) in the surface direction of the sheet body (22a).

11. The electrostatic transducer (1a, 1b, 1c) according to claim 9, wherein: The bonding restriction layer (20) has a plurality of through slits (22c), The second joining portion (62) is formed by directly joining the insulating sheet (11) and the covering portion (30b) of the lead wire (30) by passing at least one of the insulating sheet (11) and the covering portion (30b) of the lead wire (30) through the slit (22c).

12. The electrostatic transducer (1a, 1b, 1c) according to claim 8, wherein: The joint restriction layer (20) is a resin sheet formed of a thermoplastic material.

13. The electrostatic transducer (1a, 1b, 1c) according to claim 8, wherein: The bonding restriction layer (20) is formed in a long strip shape, and one end in the length direction is arranged at the end edge of the first electrode sheet (12).

14. The electrostatic transducer (1a, 1b, 1c) according to claim 13, wherein: The joint restriction layer (20) is formed such that the other end in the longitudinal direction is narrower than the one end in the longitudinal direction.

15. The electrostatic transducer (1b, 1c, 1e, 1g, 1h, 1j) according to any one of claims 1 to 3, wherein: The first electrode sheet (12) is arranged in a region corresponding to the first region (Pa), and is not arranged in a region corresponding to the second region (Pb).

16. The electrostatic transducer (1b, 1c, 1e) according to claim 15, wherein: The lead wire (30) is arranged between the insulator sheet (11) and the first electrode sheet (12).

17. The electrostatic transducer (1g, 1h, 1j) according to claim 15, wherein The first electrode sheet (12) is arranged between the insulator sheet (11) and the lead wire (30).

18. The electrostatic transducer (1h, 1j) according to claim 17, wherein The electrostatic transducer (1h, 1j) further comprises a bonding auxiliary layer (80, 101) in the second region (Pb), wherein the bonding auxiliary layer (80, 101) is formed of a thermoplastic material and is arranged between the insulating sheet (11) and the covering portion (30b) of the lead (30). The second joining portion (62) is formed by a portion of the joining auxiliary layer (80, 101).

19. The electrostatic transducer (1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i, 1j) according to any one of claims 1 to 3, wherein: The first electrode sheet (12) has a plurality of through holes.

20. The electrostatic transducer (1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i, 1j) according to claim 19, wherein The first electrode sheet (12) is formed of conductive cloth.

21. The electrostatic transducer (1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i, 1j) according to claim 19, wherein The first electrode sheet (12) is formed of a thermoplastic elastomer containing a conductive filler. The first joint portion (61) is formed by a portion of the first electrode sheet (12).

22. The electrostatic transducer (1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i, 1j) according to any one of claims 1 to 3, wherein: The first joining portion (61) is a portion where the first electrode sheet (12) and the core wire (30a) of the lead wire (30) are joined by ultrasonic welding.

23. The electrostatic transducer (1d, 1e, 1f, 1g, 1i) according to claim 22, wherein: The second joining portion (62) is a portion where the insulating sheet (11) and the covering portion (30b) of the lead wire (30) are joined by ultrasonic welding.

24. The electrostatic transducer (1j) according to any one of claims 1 to 3, wherein: The electrostatic transducer (1j) further comprises a second electrode sheet (13) disposed on the second surface of the insulating sheet (11) and serving as a shielding electrode. The resistivity of the second electrode sheet (13) is set to be smaller than the resistivity of the first electrode sheet (12).

25. The electrostatic transducer (1j) according to claim 24, wherein The first electrode sheet (12) is formed of a thermoplastic elastomer containing a conductive filler. The second electrode sheet (13) is formed of conductive cloth.

26. The electrostatic transducer (1j) according to claim 24, wherein The first electrode sheet (12) and the second electrode sheet (13) are formed of a thermoplastic elastomer containing a conductive filler.

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