JP6379984B2 - Fixed pole and electroacoustic transducer - Google Patents

Description

  The present invention relates to an electrostatic electroacoustic transducer and a fixed pole used in the electroacoustic transducer.

  Patent Document 1 discloses that a rectangular frame is applied to a thin flat plate surface speaker. Patent Document 2 discloses that an outer edge portion of a thin electrostatic speaker is sandwiched between frames, and Patent Document 3 discloses an insulator between an electrode and a vibrating body of the electrostatic speaker. And disposing a frame-shaped spacer.

JP 2012-039555 A JP 2013-145111 A JP 2012-39597 A

  According to the inventions of Patent Literatures 1-3, a rectangular shape can be maintained by the frame. However, it is necessary to manufacture a frame body separately from the speaker and attach the manufactured frame body to the speaker.

  The present invention has been made under the background described above, and the shape of the electrostatic electroacoustic transducer can be obtained without manufacturing and attaching a frame separately from the main body of the electrostatic electroacoustic transducer. It is an object to provide a technology that can maintain the above.

  The present invention is a fixed pole that forms a capacitance between the opposing vibrating body, a first region facing the vibrating body, and a region outside the edge of the first region as a bending region, A fixed pole having a second region forming a frame of the fixed pole.

In the present invention, the second region may have a folded region.
In the present invention, the second region may have a curved region.
The present invention also provides an electrostatic electroacoustic transducer having a fixed pole having any one of the above configurations.

  According to the present invention, the shape of the electrostatic electroacoustic transducer can be maintained without manufacturing and attaching the frame separately from the main body of the electrostatic electroacoustic transducer.

1 is an external view of an electrostatic electroacoustic transducer 1 according to an embodiment of the present invention. FIG. 2 is an exploded view of the electrostatic electroacoustic transducer 1. FIG. AA sectional view taken on the line AA of FIG. The enlarged view of the cross section of the electrostatic electroacoustic transducer 1. FIG. The figure which showed an example of the position of a convex part. The figure which showed the electrical structure which concerns on the electrostatic electroacoustic transducer. The figure which showed the expanded view and fixed cross section of the fixed pole which concern on a modification. The figure which showed the expanded view and fixed cross section of the fixed pole which concern on a modification. The figure which showed the expanded view and fixed cross section of the fixed pole which concern on a modification. The perspective view of the fixed pole which concerns on a modification. The perspective view of the fixed pole which concerns on a modification.

[Embodiment]
1 is an external view of an electrostatic electroacoustic transducer 1 according to an embodiment of the present invention, FIG. 2 is an exploded view of the electrostatic electroacoustic transducer 1, and FIG. 3 is a fixed pole 20U described later. FIG. 4 is a cross-sectional view taken along the line AA in FIG. 1, and FIG. 5 is an enlarged view of the cross section of the electrostatic electroacoustic transducer 1. FIG. In the figure, directions are indicated by orthogonal X-axis, Y-axis, and Z-axis, and the left-right direction when the electrostatic electroacoustic transducer 1 is viewed from the front side in the direction of arrow B in FIG. The direction and the front-rear direction are the Y-axis direction, and the height (vertical) direction is the Z-axis direction. Further, in the figure, “●” in “◯” means an arrow heading from the back of the drawing to the front. Further, in the figure, “x” in “◯” means an arrow pointing backward from the front of the drawing. In addition, the dimension of each member in the drawing is different from the actual dimension so that the shape and positional relationship of each member can be easily understood.

  The electrostatic electroacoustic transducer 1 includes a vibrating body 10, a fixed pole 20U, and a fixed pole 20L. In the present embodiment, the configuration of the fixed pole 20U and the fixed pole 20L is the same. For this reason, when there is no particular need to distinguish between the fixed pole 20U and the fixed pole 20L, descriptions such as “L” and “U” at the end of the reference numerals are omitted.

  The rectangular vibrating body 10 as viewed from above is a film made of a synthetic resin film (insulating layer) having insulating properties and flexibility such as PET (polyethylene terephthalate) or PP (polypropylene). The conductive film (conductive layer) is formed by vapor-depositing a conductive metal on one of the surfaces.

  The fixed electrode 20 is a member in which a plastic and insulating synthetic resin sheet (insulating layer) such as PET or PP, paper, a conductive metal conductive film (conductive layer), and paper are laminated in this order. . The fixed pole 20 has a rectangular shape when viewed from above, and includes a facing portion 201 facing the vibrating body 10 and a frame-shaped frame portion 202. In the present embodiment, the conductive film is laminated in the region of the facing portion 201 and is not laminated on the frame portion 202. Further, paper or a conductive film may not be stacked on the frame portion 202, and only the insulating layer may be used. In addition, the fixed electrode 20 may have a configuration in which paper is not laminated, and a synthetic resin, a conductive film, and a synthetic resin are laminated in this order.

  The frame portion 202 (second region) forming the frame of the fixed pole 20 is a bending region provided outside the edge of the rectangular opposing portion 201 (first region) shown in FIG. The portion 204 is bent, and the adjacent frame portions 202 are formed by applying and bonding an adhesive to the adhesive allowance 203A and the adhesive allowance 203B.

The bent portion 204 has a first region 211, a second region 212, a third region 213, and a fourth region 214. When forming the frame portion 202, for example, the boundary between the fourth region 214 and the third region 213 is valley-folded, and then the boundary between the third region 213 and the second region 212 is valley-folded. Next, after folding the boundary between the second region 212 and the first region 211, the boundary between the first region 211 and the facing portion 201 is folded.
FIG. 3B is a view showing a cross section when the bent portion 204 is bent. After each region is bent, an adhesive is applied to the rectangular margin 203C and the fourth region 214, and the margin 203C and the fourth region 214 are adhered to the opposing portion 201. In addition, the boundary between the trapezoid-shaped adhesive margin 203A and the first region 211 is folded, and the adjacent first regions 211 are bonded to each other with the adhesive margin 203A applied with an adhesive, and the rectangular adhesive margin 203B and the first region 211 The boundary of the three regions 213 is bent, and the adjacent third regions 213 are bonded together with a glue margin 203B to which an adhesive is applied.

  In the fixed pole 20 in which the frame part 202 is formed, the facing part 201 to which a voltage is applied becomes a region for forming a capacitance between the opposing vibrating body 10 and the frame part 202 to which no voltage is applied is The region does not face the vibrating body 10 and does not form a capacitance with the vibrating body 10. In addition, about the part to be bent, a perforation and a groove | channel may be provided and it may be made easy to bend. Further, in the fixed electrode 20, a synthetic resin layer may not be provided in a portion that becomes the frame portion 202.

  The fixed electrode 20 has a plurality of holes penetrating from the front surface to the back surface, and allows passage of air and sound waves. In addition, the fixed pole 20 has a flat portion 21 and a plurality of convex portions 22 that are connected to the flat portion 21 and protrude toward the vibrating body 10 on the insulating layer side of the facing portion 201. In addition, in FIGS. 1-3, illustration of this hole and the convex part 22 is abbreviate | omitted.

  In this embodiment, the convex portion 22 in the shape of a truncated cone is formed by embossing. As shown in FIG. 6, the fixed pole 20 </ b> L has a predetermined distance in the left-right direction and the front-rear direction. Is provided. Although not shown, in the fixed pole 20U as well as in the fixed pole 20L, on the insulating layer side, it is predetermined in the left-right direction and the front-rear direction at a position facing the convex portion 22 of the fixed pole 20L. A convex portion 22 is provided at a predetermined distance. In FIG. 6, illustration of a plurality of holes penetrating from the front surface to the back surface is omitted. Moreover, the shape of the convex part 22 is not limited to a truncated cone, and may be another shape.

  In the example shown in FIGS. 4 and 5, the upper surface of the fixed pole 20U and the lower surface of the fixed pole 20L have dents by an embossing mold, but the embossing is performed on the upper side of the fixed pole 20U. The single-side embossing may be performed so that the entire surface of and the entire lower surface of the fixed pole 20L are flat. Further, in the plurality of convex portions 22, it is preferable that the height from the flat portion 21 to the top end of the convex portion 22 in the vertical direction is uniform, but it is not uniform as long as it is within a predetermined tolerance range. Good.

  When the vibrating body 10 and the fixed pole 20 are fixed, an adhesive is applied to the tip of the convex portion 22 so that the tip of the convex portion 22 of the fixed pole 20U and the tip of the convex portion 22 of the fixed pole 20L face each other. Then, the vibrating body 10 is sandwiched between the fixed pole 20U and the fixed pole 20L, and pressure is applied from above on the surface plate. Since the plurality of convex portions 22 have a uniform height from the flat portion 21 to the top end in the vertical direction of the convex portion 22, the distance from the vibrating body 10 to the fixed pole 20 </ b> U after fixing is the convex portion from the flat portion 21. The distance from the vibrating body 10 to the fixed pole 20L is also the same as the height from the flat surface portion 21 to the vertical tip of the convex portion 22. A portion of the vibrating body 10 that is not in contact with the convex portion 22 is located between the fixed pole 20U and the fixed pole 20L with an air layer interposed therebetween, and can vibrate in the vertical direction. Further, after fixing the fixed pole 20 and the vibrating body 10, the strength of the peripheral edge of the fixed pole 20 is increased by the frame portion 202 formed by bending, and the strength of the fixed pole 20 is improved.

Next, an electrical configuration relating to the electrostatic electroacoustic transducer 1 will be described. As shown in FIG. 7, the electrostatic electroacoustic transducer 1 includes an amplifier unit 130 to which an acoustic signal representing sound is input, a transformer 110, and a bias power source 120 that applies a DC bias to the vibrating body 10. The provided drive circuit 100 is connected.
The fixed pole 20U is connected to the secondary terminal T1 of the transformer 110, and the fixed pole 20L is connected to the other secondary terminal T2 of the transformer 110. In addition, the vibrating body 10 is connected to the bias power source 120 via the resistor R1. The middle point terminal T3 of the transformer 110 is connected to the ground GND, which is the reference potential of the drive circuit 100, via the resistor R2.
An acoustic signal is input to the amplifier unit 130. The amplifier unit 130 amplifies the input acoustic signal and outputs the amplified acoustic signal. The amplifier unit 130 includes terminals TA1 and TA2 that output acoustic signals. The terminal TA1 is connected to the primary terminal T4 of the transformer 110 via the resistor R3, and the terminal TA2 is connected to the resistor R4. Is connected to the other terminal T5 on the primary side of the transformer 110.

  When an AC acoustic signal is input to the amplifier unit 130, the input acoustic signal is amplified and supplied to the primary side of the transformer 110. When the acoustic signal boosted by the transformer 110 is supplied to the fixed pole 20 and a potential difference is generated between the fixed pole 20U and the fixed pole 20L, the vibrating body 10 between the fixed pole 20U and the fixed pole 20L. The electrostatic force that is attracted to either the fixed pole 20U or the fixed pole 20L acts.

  Specifically, the polarity of the second acoustic signal output from the terminal T2 is opposite to that of the first acoustic signal output from the terminal T1. When a positive polarity acoustic signal is output from the terminal T1 and a negative polarity acoustic signal is output from the terminal T2, a positive voltage is applied to the fixed pole 20U, and a negative voltage is applied to the fixed pole 20L. Is done. Since a positive voltage is applied to the vibrating body 10 by the bias power supply 120, the vibrating body 10 is weak in electrostatic attraction with the fixed pole 20U to which the positive voltage is applied, while a negative voltage is applied. The electrostatic attraction between the fixed pole 20L being applied is strengthened. A portion of the vibrating body 10 that is not in contact with the convex portion 22 is displaced toward the fixed pole 20L (downward) by an attractive force acting on the fixed pole 20L according to the difference in electrostatic attraction applied to the vibrating body 10.

  Further, when a first acoustic signal having a negative polarity is output from the terminal T1, and a second acoustic signal having a positive polarity is output from the terminal T2, a negative voltage is applied to the fixed pole 20U, and the fixed pole 20L is applied. A positive voltage is applied. Since a positive voltage is applied to the vibrating body 10 by the bias power supply 120, the vibrating body 10 is weakened in electrostatic attraction with the fixed pole 20L to which the positive voltage is applied, while a negative voltage is applied. The electrostatic attraction between the fixed pole 20U being applied is strengthened. A portion of the vibrating body 10 that is not in contact with the convex portion 22 is displaced toward the fixed pole 20U (upward) due to an attractive force acting on the fixed pole 20U according to the difference in electrostatic attraction applied to the vibrating body 10.

  As described above, the vibrating body 10 is displaced upward or downward (flexure) according to the acoustic signal, and the displacement direction is sequentially changed to generate vibration, which corresponds to the vibration state (frequency, amplitude, phase). Sound waves are generated from the vibrating body 10. The generated sound wave passes through the fixed electrode 20 having sound permeability and is radiated as sound to the outside of the electrostatic electroacoustic transducer 1.

According to the present embodiment, since the frame portion 202 formed by bending functions as a frame, the frame portion 202 can be used for the peripheral portion of the electrostatic electroacoustic transducer 1 without attaching a spacer separately from the fixed pole 20. The strength is improved and the shape of the electrostatic electroacoustic transducer 1 can be maintained. Moreover, in this embodiment, since the fixed pole 20 is formed with a synthetic resin, paper, or a conductive film, the weight of the electrostatic electroacoustic transducer 1 can be reduced. Further, since the fixed electrode 20 can be made of an inexpensive material such as synthetic resin or paper, the cost for manufacturing the electrostatic electroacoustic transducer 1 can be suppressed.
Further, when the electrostatic electroacoustic transducer 1 is arranged on the wall, the frame portion 202 is in contact with the wall surface, and a space is secured between the wall surface and the facing portion 201 by the height of the frame portion 202. Since the air in this space moves through a hole provided in the fixed electrode 20, even if the electrostatic electroacoustic transducer 1 is disposed on the wall, the vibrating body 10 can be vibrated to emit sound. it can.
In addition, for example, when the fixed electrode 20 is a metal plate, if a hole for sound emission is formed in the fixed electrode 20, burrs are generated in the process, and thus it is necessary to remove the burrs. In the form, since the fixed electrode 20 has a paper layer, even when a hole is formed in the fixed electrode 20 by pressing, the generation of burrs can be suppressed.

[Modification]
As mentioned above, although embodiment of this invention was described, this invention is not limited to embodiment mentioned above, It can implement with another various form. For example, the present invention may be implemented by modifying the above-described embodiment as follows. In addition, you may combine each of embodiment mentioned above and the following modifications.

In the above-described embodiment, the frame portion 202 is formed by bending and bending a region outside the edge of the facing portion 201. However, the configuration for forming the frame portion 202 is limited to the configuration of the above-described embodiment. It is not something.
FIG. 8A is a development view of the fixed pole 20A according to one modification of the present invention, and FIG. 8B is an enlarged view of a cross section of the frame portion 202A of the fixed pole 20A. As shown in FIG. 8A, even if the rectangular bent portion 204A is heated and plastically deformed in a deployed state, the frame portion 202A (second region) is formed into a cylindrical shape. Good. Further, when the bending portion 204A is subjected to a bending process, the bending portion 204A may be bent into a shape other than the cylindrical shape, for example, a semi-cylindrical shape obtained by dividing the cylinder in half.
9A is a development view of a fixed pole 20B according to a modification of the present invention, and FIG. 9B is an enlarged view of a cross section of the frame portion 202B of the fixed pole 20B. In the unfolded state, the rectangular bent portion 204B is bent in the direction opposite to that of the vibrating body 10, and an adhesive is applied to the adhesive allowance 203A and bonded to the adjacent bent portion 204B from the outside to form the frame portion 202B (second region). ) To improve the strength of the peripheral edge of the fixed electrode 20.

In the embodiment described above, the portion that is bent in the unfolded fixed pole 20 is the peripheral portion of the fixed pole 20, but is not limited to the peripheral portion, and other portions may be bent. Good.
FIG. 10A is a development view of a fixed pole 20C according to a modification of the present invention, and FIG. 10B is an enlarged view of a part of the cross section of the fixed pole 20C. As in the example shown in FIG. 9, the rectangular bent portion 204 </ b> C is folded in the direction opposite to the vibrating body 10 in the unfolded state, and an adhesive is applied to the adhesive allowance 203 </ b> A and bonded to the adjacent bent portion 204 </ b> C. Thus, the frame portion 202C is formed (second region). Further, as shown in FIG. 10B, the second bent portion 205 is bent so as to protrude toward the opposite side of the vibrating body 10 to form a folded portion 206 (second region). Also good.
According to this configuration, for example, when a poster is pasted on the frame portion 202C, the central portion of the poster is supported by the folding portion 206, so that the poster can be easily pasted and held easily. Further, a space is secured between the poster and the facing portion 201 by the height of the folded portion 206. Since the air in this space moves through the hole provided in the fixed electrode 20, even if a poster is attached to the electrostatic electroacoustic transducer 1, the vibrating body 10 can be vibrated to emit sound. it can.
In the configuration illustrated in FIG. 10, both the frame portion 202 </ b> C and the folded portion 206 are configured. However, the frame portion 202 </ b> C may be omitted and a plurality of folded portions 206 may be configured.

  In the embodiment described above, a picture or a photograph may be printed on the surface of the fixed pole 20 opposite to the side facing the vibrating body 10. Further, in the configuration in which a picture or a photograph is printed on the fixed pole 20 in this way, a sound emitting hole may be opened in the fixed pole 20 after printing.

  In the embodiment described above, a gap is ensured between the vibrating body 10 and the fixed pole 20 by the convex portion 22. However, in the configuration in which the convex portion 22 is not provided on the fixed pole 20, the vibrating body 10 and the fixed pole are provided. A member that functions as a spacer, such as a non-woven fabric, may be disposed between the vibrating body 10 and the fixed electrode 20.

In the embodiment described above, the frame portion and the folded portion are formed by bending the flat fixed pole 20 in the unfolded state, but the method of forming the frame portion and the folded portion is another method. May be. For example, a frame portion 202D (second region) that is bent into a frame shape as in the fixed pole 20D shown in FIG. 11 by performing a pressing process that is an example of a process of bending the peripheral portion of the facing portion 201 with a mold. May be formed.
Further, when pressing the fixed pole, not only the frame portion 202D but also the two parallel sides of the frame portion 202D are projected to the opposite side as shown in FIG. You may make it form the beam part 207 (2nd area | region) which became. In FIG. 12, the beam portion 207 is linear, but the two beam portions 207 intersect each other, and the fixed pole is convex in a lattice shape by the frame portion 202D and the beam portion. It is good also as a structure which has a part.

  The electrostatic electroacoustic transducer 1 of the above-described embodiment operates as a speaker that emits sound. However, the configuration of the above-described embodiment or modification may be applied to a microphone that is an electroacoustic transducer. It is. When the present invention is operated as a speaker, the circuit shown in FIG. 7 can be used. When the electrostatic electroacoustic transducer 1 is used as a microphone, in the drive circuit 100, the direction of a signal input to and output from the amplifier unit 130 is opposite to that when the amplifier is used as a speaker. When sound waves are generated outside the electrostatic electroacoustic transducer 1, the vibrating body 10 vibrates due to the sound waves that reach the electrostatic electroacoustic transducer 1. When the vibrating body 10 vibrates, the potential of the fixed pole 20 changes. This change in the potential of the fixed electrode 20 corresponds to the vibration displacement of the vibrating body 10 and is supplied as an acoustic signal to the transformer 110 via the terminal T1 and the terminal T2. Then, the transformer 110 transforms this acoustic signal and inputs it to the amplifier unit 130. The amplifier unit 130 amplifies this acoustic signal and outputs it to a speaker or a computer (not shown).

DESCRIPTION OF SYMBOLS 1 ... Electrostatic type electroacoustic transducer, 10 ... Vibrating body, 20, 20U, 20L ... Fixed pole, 21 ... Planar part, 22 ... Convex part, 100 ... Drive circuit, 110 ... Transformer, 120 ... Bias power supply, 130 ... Amplifier part 201 ... opposite part 202, 202A, 202B, 202C, 202D ... frame part 203A, 203B, 203C ... paste margin, 204 ... bending part, 204A ... bending part, 204B ... bending part, 204C ... bending part 205 ... second bent portion, 206 ... folded portion, 207 ... beam portion

Claims (4)

It is a fixed pole that forms a capacitance between the opposing vibrating bodies,
A first region facing the vibrating body;
A region outside the edge of the first region as a bending region, a second region forming a frame of the fixed pole;
Having a fixed pole.   The fixed pole according to claim 1, wherein the second region has a bent region.   The fixed pole according to claim 1, wherein the second region has a curved region.   The electrostatic type electroacoustic transducer which has a fixed pole as described in any one of Claims 1 thru | or 3.

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