JP5817442B2 - Electrostatic electroacoustic transducer, electrostatic speaker, and electrostatic microphone - Google Patents

Description

  The present invention relates to an electrostatic electroacoustic transducer, an electrostatic speaker, and an electrostatic microphone.

  The electrostatic speaker system disclosed in Patent Document 1 includes a pair of electrostatic speakers. The left electrostatic speaker is used for reproducing left audio, and the right electrostatic speaker is used. Stereo audio can be reproduced for right-side audio reproduction.

JP 2001-148893 A

In general, it is known that an electrostatic speaker has high directivity and the output sound does not spread so much in space. Therefore, in the flat speaker system disclosed in Patent Document 1, the sound output from the left electrostatic speaker and the sound output from the right electrostatic speaker can be heard by the listener in a separated state. There is.
Therefore, there is a need for a mechanism that switches between a mixed state and a separated state when a plurality of sounds output from a plurality of electrostatic speakers are heard by a listener. This switching is desired to be performed without changing the shape or moving the position of the electrostatic speaker from the viewpoint of simplifying the configuration.

  The configuration of the electrostatic speaker can also be used as the configuration of the electrostatic microphone. In this case, sound waves (sound waves) are converted into acoustic signals (electric signals) by sound waves generated outside vibrating the diaphragm. In this electrostatic microphone, it is desired to expand or narrow the space in which the sound converted into one acoustic signal is collected without changing the shape of the diaphragm or moving the position. ing.

  The present invention provides a mechanism for allowing a listener to listen to a mixed sound output from an electrostatic speaker without changing the shape or position, or to allow a listener to listen to a separated sound. With the goal. It is another object of the present invention to provide a mechanism for expanding or narrowing a region in which an electrostatic microphone collects sound without changing the shape or position.

In order to solve the above-described problems, an electrostatic speaker according to the present invention includes a first vibrating body having conductivity, a first electrode facing the first vibrating body, and the first electrode. A first electrostatic sound emitting unit including an insulating first separation member that separates the first vibrating body, a second vibrating body having conductivity, and the second vibrating body. A second electrostatic sound emitting section including a second electrode that performs, an insulating second spacing member that separates the second electrode and the second vibrating body, and a third having conductivity. A third electrode, a third electrode facing the third vibrating body, and an insulating third spacing member that separates the third electrode and the third vibrating body. An electrostatic sound emitting unit, a first application unit that applies a voltage according to a first audio signal to the first electrode, and the third electrode A second application unit that applies a voltage according to a second audio signal different from the first audio signal, and the first audio signal, the second audio signal, and the volume with respect to the second electrode A third application unit that selects any one of the audio signals indicating a sound that is less than a predetermined threshold and applies a voltage according to the selected audio signal, and the first electrode includes: A first electrode portion, and a second electrode portion having a shape protruding from the first electrode portion toward the second electrode, the second electrode including a third electrode portion, A fourth electrode portion having a shape projecting from the third electrode portion toward the first electrode, and the fourth electrode portion is disposed at a position sandwiched between the two second electrode portions. Or the second electrode portion in a position sandwiched between two fourth electrode portions. Are arranged so that the first electrostatic sound emitting unit and the second electrostatic sound emitting unit are supported, and the third electrostatic sound emitting unit is provided with the first static sound emitting unit. It arrange | positions in the position which pinches | interposes said 2nd electrostatic sound emission part between electrical sound emission parts.

  Preferably, as the distance from the first electrode portion increases, the width of the second electrode portion gradually decreases, and as the distance from the third electrode portion increases, the width of the fourth electrode portion increases. The width should be gradually reduced.

Further, electrostatic microphone according to the present invention includes a first vibrator having conductivity, the first and the first electrode facing the vibrating body, said first electrode and said first vibrator A first output unit that outputs a first audio signal generated in the first electrode in response to vibration of the first vibrating body; A conductive second vibrating body, a second electrode facing the second vibrating body, and an insulating second spacing member that separates the second electrode and the second vibrating body A second output unit for outputting a second audio signal different from the first audio signal generated at the second electrode in response to the vibration of the second vibrating body, and having conductivity. A third vibrating body, a third electrode facing the third vibrating body, the third electrode, and the third vibration And a third separating member insulating for separating the door is generated in the third electrode in response to the vibration of the third vibrator, said first and second voice signals different from the third When one of the third output unit that outputs an audio signal and the first, second, and third output units is selected and the first output unit is selected, the second output unit is selected . the audio signal is mixed with the first audio signal output to the first output portion, wherein when selecting the second output unit, the second audio signal of the first and third When the third output unit is selected without being mixed with any of the audio signals, the second audio signal is mixed with the third audio signal and the third output unit is selected. Output selection means for outputting to a third output unit, wherein the first electrode is a first electrode part and the first electrode part. A second electrode portion having a shape projecting toward the second electrode, the second electrode extending from the third electrode portion toward the first electrode. And the third electrode is disposed at a position sandwiching the second electrode with the first electrode, and the second electrode portion and the fourth electrode portion The fourth electrode portion is arranged such that one portion protruding from one of the electrode portions is sandwiched between two portions protruding from the other electrode portion. To do.

  According to the present invention, it is possible to make the listener listen to a plurality of sounds output from the electrostatic speaker without changing the shape or position, or to let the listener listen to the separated sound. . In addition, according to the present invention, it is possible to expand or narrow the area where the electrostatic microphone collects sound without changing the shape or position.

It is the perspective view which showed the external appearance of the electrostatic speaker which concerns on embodiment of this invention. It is a disassembled perspective view of the electrostatic speaker which concerns on the same embodiment. It is a figure which shows the shape of the electrode which concerns on the same embodiment. It is the figure which showed the electrical structure of the electrostatic speaker which concerns on the same embodiment. It is a figure for demonstrating control of the switch which concerns on the same embodiment. It is a figure which illustrates typically the shape of the vibrating body concerning the embodiment, and the sound pressure generated from the vibrating body. It is a figure explaining the example which used the electrostatic speaker which concerns on the embodiment as an advertising medium. It is a figure explaining the shape of the vibrating body which concerns on the modification of this invention, and the sound pressure which generate | occur | produced from this vibrating body. It is a figure which shows the shape of the electrode which concerns on the modification of this invention. It is a figure which shows the shape of the electrode which concerns on the modification of this invention. It is the perspective view which showed the external appearance of the electrostatic speaker 1f which concerns on the modification of this invention. It is a figure which shows the external appearance of the electrostatic type speakers 1g and 1h in the modification of this invention. It is the figure which showed the electrical constitution of the electrostatic microphone 1M which concerns on the modification of this invention.

[Embodiment]
FIG. 1 is a perspective view showing an external appearance of an electrostatic speaker 1 according to an embodiment of the present invention. In the following drawings, X, Y, and Z mean coordinate axes of a three-axis orthogonal coordinate system. The X and Y axes orthogonal to each other are both parallel to the sound emitting surface of the electrostatic speaker 1, and the Z axis is perpendicular to the sound emitting surface of the electrostatic speaker 1. The electrostatic speaker 1 includes a vibrating body 10, electrodes 20U-1, 20U-2, 20U-3, electrodes 20L-1, 20L-2, 20U-3, and spacers 30U, 30L. The configuration and operation of the spacer 30U and the spacer 30L, the configuration and operation of the electrode 20U-1 and the electrode 20L-1, the configuration and operation of the electrode 20L-2 and the electrode 20U-2, and the electrode 20L-3 and the electrode 20U-3 Since the configuration and operation are the same, the description of “L” and “U” is omitted unless it is particularly necessary to distinguish between the two. As an example of the size of the electrostatic speaker 1, the length in the Y-axis direction is about several meters, for example, and the length in the X-axis direction is about several tens of centimeters. The dimensions of each part constituting the electric speaker 1 are different from the actual dimensions so that the shape of each part can be easily understood. The thickness of the electrostatic speaker 1 (the length in the Z-axis direction) is actually smaller than that shown in FIG. 1, and the electrostatic speaker 1 has a sheet-like shape as a whole. Further, in the following figures, “•” in “◯” means an arrow from the back of the drawing to the front among the arrows indicating the direction of the coordinate axes.

(Configuration of each part of the electrostatic speaker 1)
First, each part constituting the electrostatic speaker 1 will be described. FIG. 2 is an exploded perspective view of the electrostatic speaker 1. The vibrating body 10 is obtained by forming a conductive metal conductive film on the surface of a transparent film such as PET (polyethylene terephthalate) or PP (polypropylene). Since the vibrating body 10 has a thin film shape with a thickness of about several μm, it is freely deformed when subjected to an external force. The vibrating body 10 has a rectangular shape when viewed from the Z-axis direction.

  The spacer 30 is a frame member that is formed of an insulating material and has a rectangular shape when viewed from the positive Z-axis direction. The spacer 30 separates the vibrating body 10 and the electrode 20 to form an air layer between the vibrating body 10 and the electrode 20 and corresponds to a separating member. The length of the spacer 30 in the X-axis direction is the same as the length of the vibrating body 10 in the X-axis direction. Similarly, the length of the spacer 30 in the Y-axis direction and the length of the vibrating body 10 in the Y-axis direction are the same. Also, the lengths of the spacer 30U and the spacer 30L in the Z-axis direction are the same. Note that the shape of the spacer 30 is not limited to a rectangle, and may be any shape as long as the vibrating body 10 and the electrode 20 are not in contact with each other.

  The electrode 20-1, the electrode 20-2, and the electrode 20-3 are so-called punching metal, and are provided with a plurality of through holes penetrating from the front surface to the back surface of a conductive metal plate at a predetermined interval. is there. In addition, illustration of this through-hole is abbreviate | omitted in drawing. As shown in FIGS. 1 and 2, the electrode 20-1, the electrode 20-2, and the electrode 20-3 are formed in a comb shape when viewed from the positive direction of the Z axis. As used herein, the comb-like shape refers to a state in which a plurality of cuts are made at a certain interval on one side of a certain member as if the shape of a comb tooth. Specifically, as illustrated in FIG. 2, the electrode 20U-1 includes a base portion 20U-A and comb-tooth portions 20U-B1 to B3 protruding from the base portion 20U-A toward the electrode 20U-2. The electrode 20U-2 includes a base portion 20U-C, comb tooth portions 20U-D1 to D3 protruding from the base portion 20U-C toward the electrode 20U-1, and further from the base portion 20U-C toward the electrode 20U-3. It has the comb-tooth part 20U-E1-E3 which protrudes. The electrode 20U-3 includes a base portion 20U-F and comb-tooth portions 20U-G1 to G3 protruding from the base portion 20U-F toward the electrode 20U-2.

  The electrode 20L-1 includes a base 20L-A and comb-tooth portions 20L-B1 to B3 protruding from the base 20L-A toward the electrode 20L-2. The electrode 20L-2 includes a base 20L- C, comb tooth portions 20L-D1 to D3 protruding from the base portion 20L-C toward the electrode 20L-1, and comb tooth portions 20L-E1 to E3 protruding further from the base portion 20L-C toward the electrode 20L-3 And have. The electrode 20L-3 includes a base portion 20L-F and comb-tooth portions 20L-G1 to G3 protruding from the base portion 20L-F toward the electrode 20L-2. In each electrode pair, the upper electrode 20U and the lower electrode 20L have the same pattern shape. That is, the pattern of the shape of the protruding peak part and the other valley part is in phase.

  The configurations and operations of the base portion 20U-A and the base portion 20L-A, and the configurations and operations of the comb-tooth portions 20U-B1 to B3 and the comb-tooth portions 20L-B1 to B3 are the same. The description of “L” and “U” is omitted unless particularly necessary. Further, the configuration and operation of the base portion 20U-C and the base portion 20L-C, the configuration and operation of the comb tooth portions 20U-D1 to D3 and the comb tooth portions 20L-D1 to D3, and the comb tooth portions 20U-E1 to E3 and the comb teeth Since the configurations and operations of the portions 20L-E1 to E3 are the same, the description of “L” and “U” is omitted unless it is particularly necessary to distinguish the two. The configurations and functions of the base portion 20U-F and the base portion 20L-F, and the configurations and operations of the comb-tooth portions 20U-G1 to G3 and the comb-tooth portions 20L-G1 to G3 are the same. The description of “L” and “U” is omitted unless particularly necessary.

  The base 20-A corresponds to the first electrode portion, and the comb-tooth portions 20-B1 to B3 correspond to the second electrode portion. The base portion 20-C corresponds to a third electrode portion, the comb tooth portions 20-D1 to D3 correspond to a fourth electrode portion, and the comb tooth portions 20-E1 to E3 correspond to a fifth electrode portion. The base 20-F corresponds to a sixth electrode portion, and the comb-tooth portions 20-G1 to G3 correspond to a seventh electrode portion. The comb tooth portions 20-B1 to B3, the comb tooth portions 20-D1 to D3, the comb tooth portions 20-E1 to E3, and the comb tooth portions 20-G1 to G3 have, for example, a rectangular shape when viewed from the positive direction of the Z axis. ing. When the length of the electrostatic speaker 1 in the Y-axis direction is about 3 m, for example, comb teeth 20-B1 to B3, comb teeth 20-D1 to D3, comb teeth 20-E1 to E3, and comb teeth The length of the portions 20-G1 to G3 in the Y-axis direction is, for example, about 0.3 m.

  The length in the X-axis direction between the comb-tooth portion 20-B1 and the comb-tooth portion 20-B2 is longer than the length in the X-axis direction of the comb-tooth portion 20-D1. The length in the X-axis direction between the comb-tooth portion 20-B2 and the comb-tooth portion 20-B3 is longer than the length in the X-axis direction of the comb-tooth portion 20-D2. And the length of the X-axis direction between the comb-tooth part 20-D2 and the comb-tooth part 20-D3 is longer than the length of the X-axis direction of the comb-tooth part 20-B3. The length in the X-axis direction between the comb-tooth portion 20-D2 and the comb-tooth portion 20-D1 is longer than the length in the X-axis direction of the comb-tooth portion 20-B2. When the length of the electrostatic speaker 1 in the X-axis direction is about 60 cm, for example, the lengths of the comb-tooth portions 20-B1 to B3 and the comb-tooth portions 20-D1 to D3 in the X-axis direction are, for example, 4 to It is about 4.5 cm. Since each comb-tooth part has the relationship as described above, the electrode 20-1 and the electrode 20-2 can be engaged (interlaced) as illustrated. Since the comb-tooth portions 20-B1 to B3 and the comb-tooth portions 20-D1 to D3 are separated in a state of being bitten, the electrode 20-1 and the electrode 20-2 are insulated from each other.

  And the relationship regarding the length of the X-axis direction of comb-tooth part 20-E1-E3 and comb-tooth part 20-G1-G3 is X-axis of comb-tooth part 20-B1-B3 and comb-tooth part 20-D1-D3. It is the same as the above relationship regarding the length of the direction. Therefore, the electrode 20-2 and the electrode 20-3 can be engaged with each other as illustrated. Since the comb-tooth portions 20-E1 to E3 and the comb-tooth portions 20-G1 to G3 are separated from each other while being bitten, the electrode 20-2 and the electrode 20-3 are insulated from each other. In addition, since the electrode 20-1 and the electrode 20-3 are separated with the electrode 20-2 interposed therebetween, they are insulated from each other.

(Structure of electrostatic speaker 1)
Next, the structure of the electrostatic speaker 1 will be described. The vibrating body 10 is sandwiched between the frames of the spacer 30U and the spacer 30L in a state where tension is applied so that no slack is generated. The vibrating body 10 is fixed to the spacer 30U and the spacer 30L by applying an adhesive with a width of several mm inward from the X-axis direction edge and the Y-axis direction edge. A portion of the vibrating body 10 where the adhesive is not applied is not fixed to the spacer 30U and the spacer 30L.

  The electrode 20U-1 and the electrode 20U-2 are in a state where the comb-tooth portions 20U-B1 to B3 and the comb-tooth portions 20U-D1 to D3 are alternately interleaved with a predetermined interval so as not to contact each other. It is fixed to the spacer 30U. The electrode 20U-2 and the electrode 20U-3 are in a state where the comb-tooth portions 20U-E1 to E3 and the comb-tooth portions 20U-G1 to G3 are alternately interleaved with a predetermined interval so as not to contact each other. It is fixed to the spacer 30U. Further, in the electrode 20L-1, the electrode 20L-2, and the electrode 20L-3, similarly to the electrode 20U-1, the electrode 20U-2, and the electrode 20U-3, the comb teeth portions 20L-B1 to B3 and the comb teeth In a state where the portions 20L-D1 to D3, the comb-tooth portions 20L-E1 to E3, and the comb-tooth portions 20L-G1 to G3 are interlaced with each other, and spaced apart from each other It is fixed to the spacer 30L.

  According to this configuration, the electrode 20U-1 faces the electrode 20L-1 with the vibrator 10 interposed therebetween, the electrode 20U-2 faces the electrode 20L-2 with the vibrator 10 sandwiched, and the electrode 20U-3 vibrates. It faces the electrode 20L-3 with the body 10 in between. That is, the electrode 20U-1 and the electrode 20L-1 correspond to a first electrode pair facing each other with the vibrating body 10 interposed therebetween, and the electrode 20U-2 and the electrode 20L-2 are a second electrode facing each other with the vibrating body 10 interposed therebetween. It corresponds to an electrode pair, and the electrode 20U-3 and the electrode 20L-3 correspond to a third electrode pair facing each other with the vibrating body 10 interposed therebetween. The comb teeth of the electrode 20-1 and the comb teeth of the electrode 20-2 are combined in an alternating manner, and the comb teeth of the electrode 20-2 and the comb teeth of the electrode 20-3 are combined. When combined in an alternating manner, the entire shape viewed from the Z-axis direction is a rectangle, and the size (the length in the X-axis direction and the Y-axis direction) is the same as the size of the vibrator 10. .

  FIG. 3 is a diagram showing the shape of the electrode 20. As shown in FIG. 3, the electrodes 20-1, 20-2, and 20-3 are arranged in the Y axis positive direction in this order. In the electrode 20-1, the comb-tooth portions 20-B1, 20-B2, and 20-B3 that are the second electrode portions are directed from the base portion 20-A that is the first electrode portion toward the electrode 20-2. In the electrode 20-2, the comb-shaped portions 20-D1, 20-D2, and 20-D3 that are the fourth electrode portions from the base portion 20-C that is the third electrode portion to the electrode 20-1 of the electrode 20-2. Protrusively toward.

  The comb-tooth portions 20-B1, 20-B2, and 20-B3 are arranged in this order with an interval in the positive direction of the X axis, and the comb-tooth portions 20-D1, 20-D2, and 20-D3 are also They are arranged in this order with a gap in the positive direction of the X axis, and they are combined with each other. Accordingly, they are arranged in the order of the comb-tooth portions 20-B1, 20-D1, 20-B2, 20-D2, 20-B3, and 20-D3 in the X-axis direction.

  Similarly, among the electrodes 20-2, the third electrode part 20-C to the fifth electrode part 20-E1, 20-E2, 20-E3 is directed to the electrode 20-3 Of the electrode 20-3, the comb electrode portions 20-G1, 20-G2, and 20-G3, which are the seventh electrode portions, from the base portion 20-F, which is the sixth electrode portion, are the electrodes 20-2. Protrusively toward.

  The comb-tooth portions 20-E1, 20-E2, and 20-E3 are arranged in this order with an interval in the positive direction of the X axis, and the comb-tooth portions 20-G1, 20-G2, and 20-G3 are also arranged. They are arranged in this order with a gap in the positive direction of the X axis, and they are combined with each other. Accordingly, they are arranged in the order of the comb-tooth portions 20-E1, 20-G1, 20-E2, 20-G2, 20-E3, 20-G3 in the X-axis direction.

  A point at the corner of the electrode 20-1 in FIG. 3 (lower left corner in FIG. 3) is defined as the origin O of the XYZ coordinates. A distance from the origin O along the Y-axis direction is expressed as a Y coordinate. The base 20-A is a part of the electrode 20-1, and includes the origin O described above. The length of the base 20-A in the Y-axis direction is the length L1. Therefore, the fundamental Y coordinate of the comb tooth portions 20-B1 to B3 protruding from the base portion 20-A toward the base portion 20-C is Y1 = L1. That is, the Y coordinate of the end opposite to the origin O among the ends of the base 20-A is Y1 = L1.

The base 20-A and the base 20-C are separated by a length L2 in the Y-axis direction. That is, among the ends of the base 20-C, the Y coordinate of the end perpendicular to the Y-axis direction and on the origin O side is Y2 = (L1 + L2).
The length of the comb-tooth portions 20-B1 to B3 in the Y-axis direction is less than the length L2. Therefore, the base portion 20-C and the comb tooth portions 20-B1 to B3 are not in contact with each other. Moreover, the length of the Y-axis direction of the comb-tooth portions 20-D1 to D3 protruding from the base portion 20-C toward the base portion 20-A is less than the length L2. Therefore, the base portion 20-A and the comb tooth portions 20-D1 to D3 are not in contact with each other.

  The length of the base 20-C in the Y-axis direction is a length L3. Therefore, the fundamental Y coordinate of the comb tooth portions 20-E1 to E3 protruding from the base portion 20-C toward the base portion 20-F is Y3 = (L1 + L2 + L3). That is, among the end portions of the base portion 20-C, the Y coordinate of the end portion on the side opposite to the origin O is Y3 = (L1 + L2 + L3).

The base 20-C and the base 20-F are separated by a length L4 in the Y-axis direction. That is, among the end portions of the base portion 20-F, the Y coordinate of the end portion that is perpendicular to the Y-axis direction and that is on the origin O side is Y4 = (L1 + L2 + L3 + L4).
The length of the comb-tooth portions 20-E1 to E3 in the Y-axis direction is less than the length L4. Therefore, the base portion 20-F and the comb tooth portions 20-E1 to E3 are not in contact with each other. Moreover, the length of the Y-axis direction of the comb tooth portions 20-G1 to G3 protruding from the base portion 20-F toward the base portion 20-C is less than the length L4. Therefore, the base portion 20-C and the comb tooth portions 20-G1 to G3 are not in contact with each other.

  The length of the base portion 20-F in the Y-axis direction is the length L5. Therefore, among the end portions of the base portion 20-F, the Y coordinate of the end portion perpendicular to the Y-axis direction and opposite to the origin O is Y5 = (L1 + L2 + L3 + L4 + L5). Note that the length (width) in the X-axis direction of the electrodes 20-1, 20-2, and 20-3 is the length Lx.

(Electrical configuration of the electrostatic speaker 1)
Next, the electrical configuration of the electrostatic speaker 1 will be described. FIG. 4 is a diagram showing an electrical configuration of the electrostatic speaker 1. As shown in FIG. 4, the electrostatic speaker 1 includes transformers 50-1, 50-2, 50-3 and input units 60-1, 60-2, 60-3 to which different audio signals are input. And a bias power supply 70 that applies a DC bias to the vibrating body 10. Here, the “voice signal” is not limited to a “voice” of a living body such as a human being or an animal, and may be a signal representing sound / sound wave. In addition, the “voice signal” may be a signal indicating a sound within the audible range, or a signal indicating a sound outside the audible range such as an ultrasonic wave.

The bias power source 70 has a positive electrode side connected to the conductive film of the vibrating body 10 and a negative electrode side connected to the midpoint of the output side of the transformers 50-1, 50-2, 50-3.
One end of the output side of the transformer 50-1 is connected to the electrode 20U-1, and the other end is connected to the electrode 20L-1 facing the electrode 20U-1. The input side of the transformer 50-1 is connected to the input unit 60-1, and when an audio signal is input to the input unit 60-1, a voltage corresponding to the audio signal is applied to the electrodes 20U-1 and 20L-. 1 is applied. In this configuration, the voltage corresponding to the audio signal input to the input unit 60-1 is applied to the electrode 20U-1 and the electrode 20L-1 that are opposed to each other with the vibrating body 10 interposed therebetween, whereby the electrostatic speaker 1 Operates as a push-pull type electrostatic speaker.

  One end on the output side of the transformer 50-2 is connected to the electrode 20U-2, and the other end is connected to the electrode 20L-2 facing the electrode 20U-2. The input side of the transformer 50-2 is connected to the input unit 60-2. When an audio signal is input to the input unit 60-2, a voltage corresponding to the audio signal is applied to the electrodes 20U-2 and 20L-. 2 is applied. In this configuration, the voltage corresponding to the audio signal input to the input unit 60-2 is applied to the electrode 20U-2 and the electrode 20L-2 facing each other with the vibrating body 10 interposed therebetween, whereby the electrostatic speaker 1 Operates as a push-pull type electrostatic speaker.

  One end on the output side of the transformer 50-3 is connected to the electrode 20U-3, and the other end is connected to the electrode 20L-3 facing the electrode 20U-3. The input side of the transformer 50-3 is connected to the input unit 60-3. When an audio signal is input to the input unit 60-3, a voltage corresponding to the audio signal is applied to the electrodes 20U-3 and 20L-. 3 is applied. In this configuration, the voltage corresponding to the audio signal input to the input unit 60-3 is applied to the electrode 20U-3 and the electrode 20L-3 facing each other with the vibrating body 10 interposed therebetween, whereby the electrostatic speaker 1 Operates as a push-pull type electrostatic speaker.

  The audio signal R, the audio signal M, and the audio signal L, which are different audio signals, are input to the input unit 60-1, the input unit 60-2, and the input unit 60-3, respectively. The audio signal R is an audio signal representing so-called background music, for example. The audio signal L is an audio signal different from the audio signal R, for example, an audio signal representing a voice of a narrator who speaks an advertising phrase about a certain product. The audio signal M is an audio signal that represents a sound whose volume is less than a predetermined threshold. Note that the audio signal M may be a signal indicating silence, and for example, no audio signal may be input to the input unit 60-2. Further, the input unit 60-2 receives the input audio signal so that the audio signal M transmitted from the input unit 60-2 to the transformer 50-2 becomes an audio signal indicating a sound having a volume less than a predetermined threshold. Attenuating means for attenuating may be provided.

  As shown in FIG. 4, the circuit on the input side includes three switches SW1, SW2, and SW3. Each of these switches determines the connection state between the terminals. The switch SW1 is a switch for branching and transmitting the audio signal R input to the input unit 60-1 to the transformer 50-2. The switch SW2 is a switch for transmitting the audio signal M input to the input unit 60-2 to the transformer 50-2. The switch SW3 is a switch for branching the audio signal L input to the input unit 60-3 and transmitting it to the transformer 50-2.

  FIG. 5 is a diagram for explaining the control of the switch. As shown in FIG. 5A, the three switches SW1, SW2, and SW3 are controlled by the control unit 80. The control unit 80 controls each switch so as to be in any one of the cases I, II, and III shown in FIG. 5B, and in each case, only one switch is ON. Control to be. The switches SW1, SW2, SW3 and the control unit 80 function as switching means in the present invention. Further, the switches SW1, SW2, SW3, the control unit 80, the input units 60-1, 60-2, 60-3, and the transformers 50-1, 50-2, 50-3 are applied with the voltage application in the present invention. Functions as a means.

As shown in FIG. 5B, when the switch SW1 is ON and the switch SW2 and the switch SW3 are OFF, the audio signal input to the input unit 60-1 is applied to the electrode 20-2. A voltage corresponding to R is applied.
In case II where the switch SW2 is ON and the switches SW1 and SW3 are OFF, a voltage corresponding to the audio signal M input to the input unit 60-2 is applied to the electrode 20-2. The
In case III where the switch SW3 is ON and the switches SW1 and SW2 are OFF, a voltage corresponding to the audio signal L input to the input unit 60-3 is applied to the electrode 20-2. The

  In any case described above, a voltage according to the audio signal R input to the input unit 60-1 is applied to the electrode 20-1, and the input unit 60-3 is applied to the electrode 20-3. A voltage corresponding to the audio signal L input to is applied.

(Operation of electrostatic speaker 1)
Next, the operation of the electrostatic speaker 1 will be described. Hereinafter, each case described above is divided into three cases: (1) Case II, (2) Case I, and (3) Case III.

(1) Case II
Each switch is in the state of case II shown in FIG. That is, a voltage corresponding to the audio signal R input to the input unit 60-1 is applied to the electrode 20-1, and a voltage corresponding to the audio signal M input to the input unit 60-2 is applied to the electrode 20-2. The voltage corresponding to the audio signal L input to the input unit 60-3 is applied to the electrode 20-3.

  FIG. 6 is a diagram schematically illustrating the shapes and sound pressures of the electrode 20 and the vibrating body 10. In addition, the broken line of Fig.6 (a) represents the shape of the comb-tooth part of the electrode 20, and the base. As shown in FIG. 6A, the shape of the first portion 10-1 of the vibrating body 10 is comb-like when viewed from the positive direction of the Z axis similarly to the shape of the electrode 20-1. The shape of the second portion 10-2 is comb-like when viewed from the positive direction of the Z-axis, like the shape of the electrode 20-2. Here, in the 1st part 10-1 of the vibrating body 10, the part between the comb-tooth part 20U-B1-B3 of the electrode 20U-1 and the comb-tooth part 20L-B1-B3 of the electrode 20L-1 is shown. The first comb-tooth region 11-B is used, and the remaining portion is the first base region 11-A.

Further, in the second portion 10-2 of the vibrating body 10, the portion between the comb-tooth portions 20U-D1 to D3 of the electrode 20U-2 and the comb-tooth portions 20L-D1 to D3 of the electrode 20L-2 is the first portion. The second comb-tooth region 11-D, and the portion between the comb-tooth portions 20U-E1 to E3 of the electrode 20U-2 and the comb-tooth portions 20L-E1 to E3 of the electrode 20L-2 is the third comb-tooth region 11 -E, and the remaining portion as the second base region 11-C.
Further, in the third portion 10-3 of the vibrating body 10, the portion between the comb-tooth portions 20U-G1 to G3 of the electrode 20U-3 and the comb-tooth portions 20L-G1 to G3 of the electrode 20L-3 is the first portion. Let it be 4 comb-tooth area | region 11-G, and let the remaining part be 3rd base area | region 11-F.

In FIG. 6B, the horizontal axis represents the Y coordinate (mm) of the position, and the vertical axis represents the sound pressure (dB) of the sound output from the vibrating body 10 at the position.
First, since only the first base region 11-A exists in the region from the origin O to the coordinate Y1 in the vibrating body 10, only the sound pressure Rα of the sound corresponding to the sound signal R can be obtained. .
Next, in the region from the coordinate Y1 to the coordinate Y2 in the vibrating body 10, since the first comb tooth region 11-B exists, the sound pressure Rβ of the sound corresponding to the audio signal R can be obtained. . Here, as shown in FIG. 6A, since the area of the first comb-tooth region 11-B is smaller than that of the first base region 11-A, the sound pressure Rβ is approximately proportional to the area. It becomes smaller than the sound pressure Rα. In this region, not only the first comb-tooth region 11-B but also the second comb-tooth region 11-D exists, so that the sound pressure Mβ of the sound corresponding to the sound signal M can also be obtained. . Therefore, in the region from the coordinate Y1 to the coordinate Y2 of the vibrating body 10, the sound pressure Mβ corresponding to the sound signal M and the sound pressure Rβ corresponding to the sound signal R can be obtained.
Since only the second base region 11-C exists in the region from the coordinate Y2 to the coordinate Y3 of the vibrating body 10, only the sound pressure Mα of the sound corresponding to the audio signal M can be obtained. Here, as shown in FIG. 6A, since the area of the second base region 11-C is larger than the area of the second comb-tooth region 11-D, the sound pressure Mα is approximately proportional to the area. It becomes larger than the sound pressure Mβ.

  Since the third comb tooth region 11-E exists in the region from the coordinate Y3 to the coordinate Y4 in the vibrating body 10, the sound pressure Mβ of the sound corresponding to the sound signal M can be obtained. Here, as shown in FIG. 6A, the area of the third comb-tooth region 11-E is smaller than that of the third base region 11-C, so that the sound pressure Mβ is approximately proportional to the area. It becomes smaller than the sound pressure Mα. At this position, not only the third comb tooth region 11-E but also the fourth comb tooth region 11-G is present, so that the sound pressure Lβ of the sound corresponding to the sound signal L can also be obtained. . Therefore, in the region from the coordinate Y3 to the coordinate Y4 of the vibrating body 10, the sound pressure Mβ corresponding to the sound signal M and the sound pressure Lβ corresponding to the sound signal L can be obtained.

  Since only the third base region 11-F exists in the region from the coordinate Y4 to the coordinate Y5 of the vibrating body 10, only the sound pressure Lα of the sound corresponding to the audio signal L can be obtained. Here, as shown in FIG. 6A, since the area of the third base region 11-F is larger than the area of the fourth comb tooth region 11-G, the sound pressure Lα is approximately proportional to the area. It becomes larger than the sound pressure Lβ.

  As described above, the electrostatic speaker 1 can make a person in the region from the coordinate Y1 to the coordinate Y2 hear a sound corresponding to the audio signal R and a sound corresponding to the audio signal M. On the other hand, the electrostatic loudspeaker 1 can make a person in the region from the position of the origin O to the coordinate Y1 hear a sound corresponding to the audio signal R, and also from the coordinate Y2 to the coordinate Y3. A person in the area can hear a sound corresponding to the audio signal M.

Similarly, the electrostatic speaker 1 can make a person in the region from the coordinate Y4 to the coordinate Y5 hear a sound corresponding to the audio signal L.
In addition, the electrostatic speaker 1 can make a person in the region from the coordinate Y3 to the coordinate Y4 hear a sound corresponding to the audio signal L and a sound corresponding to the audio signal M.

  The effect at the time of using the electrostatic speaker 1 as an advertising medium using such an action of the electrostatic speaker 1 will be described. FIG. 7 is a schematic view of the electrostatic speaker 1 used as an advertising medium. As shown in FIG. 7, the electrostatic speaker 1 assumes an example in which the outermost surface is covered with a cover member 90 having sound transmission and insulation. The insulating property of the cover member 90 reduces the possibility of unintended discharge. On the surface of the cover member 90, an image (advertisement image 91) related to the advertisement is formed. The electrostatic speaker 1 is attached to the wall with the X axis positive direction facing upward. And the audio | voice signal R showing background music is input into the input part 60-1, and the audio | voice signal L showing the advertising phrase according to the advertisement image 91 is input into the input part 60-3. In such a situation, a case where a passerby serving as a listener walks in the positive direction of the Y axis from the vicinity of the origin of the vibrating body 10 is considered.

  In Case II, an audio signal M, which is an audio signal indicating silence, is input to the input unit 60-2. Here, the silence is not limited to a sound whose volume is 0, but a sound whose volume is less than a predetermined threshold. That is, the above-described sound pressure Mα is set to be less than this predetermined threshold value.

  The passerby listens to the background music (audio signal R) emitted from the electrostatic speaker 1 from the origin O of the vibrating body 10 to the coordinate Y1. When the passerby recognizes the sound and sees the direction of sound generation, the passerby visually recognizes the advertisement image 91 covering the electrostatic speaker 1. Next, when the passerby continues walking in the positive direction of the Y axis and comes to the region from the coordinate Y1 to the coordinate Y2 of the vibrating body 10, since the sound of the audio signal M is silent, from the origin O to the coordinate Y1 Only the background music (sound signal R) whose volume is lower than that of the sound being listened to in the area is listened to.

  Next, when the passerby continues walking and comes to the region from the coordinate Y2 to the coordinate Y3 of the vibrating body 10, the sound heard by the passerby is silenced. That is, the passerby does not listen to any sound of background music (speech signal R) and advertising phrase (speech signal L). Then, when the passerby further walks and comes to the region from the coordinate Y3 to the coordinate Y4 of the vibrating body 10, the passerby listens to an advertising phrase (audio signal L). And if it exceeds the coordinate Y4, since the area | region according to the audio | voice signal M will no longer exist in the vibrating body 10, a passerby will listen only to the advertisement phrase (audio | voice signal L) whose volume became louder than before. This state continues until the passerby reaches the coordinate Y5. Therefore, in this case II, the passerby listens to the background music (speech signal R) and the advertising phrase (speech signal L) in different areas and does not hear the mixed sound.

(2) Case I
Each switch is in the state of Case I shown in FIG. That is, a voltage corresponding to the audio signal R input to the input unit 60-1 is applied to the electrode 20-1, and a voltage corresponding to the audio signal R input to the input unit 60-2 is applied to the electrode 20-2. The voltage corresponding to the audio signal L input to the input unit 60-3 is applied to the electrode 20-3.

  The passerby listens to the background music (audio signal R) emitted from the electrostatic speaker 1 from the origin O of the vibrating body 10 to the coordinate Y1. When the passerby recognizes the sound and sees the direction of sound generation, the passerby visually recognizes the advertisement image 91 covering the electrostatic speaker 1. Next, when the passerby continues walking in the positive direction of the Y axis and comes to the region from the coordinate Y1 to the coordinate Y2 of the vibrating body 10, it is transmitted to the transformer 50-2 in addition to the sound of the audio signal R. You will hear the sound indicated by the audio signal. At this time, since the audio signal transmitted to the transformer 50-2 is the audio signal R, the passerby continues to listen to the background music.

  Here, in the region from the coordinate Y1 to the coordinate Y2 of the vibrating body 10, the portion that is vibrated by the transformer 50-1 is reduced as compared to when the passerby reaches the coordinate Y1 from the origin O of the vibrating body 10. doing. Therefore, the volume of the sound by the audio signal R transmitted to the transformer 50-1 is decreasing. However, since this reduced volume is compensated by the sound generated by the audio signal R transmitted to the transformer 50-2, the passerby reaches the coordinate Y1 from the origin O even in the region from the coordinate Y1 to the coordinate Y2. Listen to background music at the same volume as before.

  And if a passerby exceeds the coordinate Y2 of the vibrating body 10, he will hear only the sound by the audio | voice signal R transmitted to the transformer 50-2. When the coordinate Y2 is exceeded, the sound due to the sound signal R transmitted to the transformer 50-1 disappears, but the volume of the sound due to the sound signal R transmitted to the transformer 50-2 increases, so that the passerby changes. Listen to the background music at a low volume. This state continues until the passerby walks in the positive direction of the Y axis from the origin O and reaches the coordinate Y3. Next, when the passerby continues walking and comes to the area from the coordinate Y3 to the coordinate Y4 of the vibrating body 10, it is advertised in addition to the sound of the background music (the audio signal R transmitted to the transformer 50-2). Listen to the phrase (audio signal L). At this time, the passerby listens to the advertising phrase corresponding to the advertisement image 91 in addition to the background music while viewing the contents of the advertisement image 91. In other words, since this is a state of listening to a mixed sound, it can be expected that this passerby will be interested in advertising in a lively atmosphere of background music.

  When the passerby continues walking in the positive direction of the Y axis, the background music cannot be heard in the region from the coordinates Y4 to the coordinates Y5 of the vibrating body 10, and only the advertising phrase is mixed with the background music. Listen at a louder volume. In this way, passers-by changes completely from the lively atmosphere of background music, so that only the advertising phrase can be heard at a louder volume, that is, the advertisement phrase is carefully listened to and the content is easy to understand Therefore, we can expect a deeper understanding of the content of the advertisement itself. Thus, the electrostatic speaker 1 can alert the listener to the advertisement by changing the sound that the listener listens to according to the relative positional relationship with the listener. Highly effective as an advertising medium for electrostatic speakers.

(3) Case III
Each switch is in the state of case III shown in FIG. That is, a voltage corresponding to the audio signal R input to the input unit 60-1 is applied to the electrode 20-1, and a voltage corresponding to the audio signal L input to the input unit 60-2 is applied to the electrode 20-2. The voltage corresponding to the audio signal L input to the input unit 60-3 is applied to the electrode 20-3.

  The passerby listens to the background music (audio signal R) emitted from the electrostatic speaker 1 from the origin O of the vibrating body 10 to the coordinate Y1. When the passerby recognizes the sound and sees the direction of sound generation, the passerby visually recognizes the advertisement image 91 covering the electrostatic speaker 1. Next, when the passerby continues walking in the positive direction of the Y axis and comes to the region from the coordinate Y1 to the coordinate Y2 of the vibrating body 10, it is transmitted to the transformer 50-2 in addition to the sound of the audio signal R. You will hear the sound indicated by the audio signal. In this case, since the audio signal transmitted to the transformer 50-2 is different from the audio signal R, the audio signal is the same as the audio signal L representing the advertising phrase, so that the passerby can hear the sound of the background music (audio signal R). In addition, the advertisement phrase (the audio signal L transmitted to the transformer 50-2) is listened to. When the passerby continues walking and reaches the coordinate Y2 of the vibrating body 10, the passerby leaves the area where he hears the sound of the audio signal R, so that the passerby only mixed the propaganda phrase with the background music. It will be heard at a louder volume.

When the passerby continues to walk and comes to the region from the coordinate Y3 to the coordinate Y4 of the vibrating body 10, the passerby adds to the audio signal L transmitted to the transformer 50-2 and the transformer 50-3. However, since these are the same advertising phrases, the passerby will not be aware of this and will continue to listen only to the advertising phrases. Moreover, in the area | region from the coordinate Y3 of the vibrating body 10 to the coordinate Y4, the sound volume by the audio | voice signal L transmitted to the transformer 50-2 is from the time of being in the area | region from the coordinate Y3 of the vibrating body 10 to the coordinate Y4. However, since the volume is compensated by the sound volume of the sound signal L transmitted to the transformer 50-3, the passerby continues to listen to the advertising phrase at the same volume.
Even in this case, as in (2), the sound that the passerby listens to while walking changes from only the background music to a sound in which an advertising phrase is added to the background music. Transition to sound only.

  The sound fields of (1) to (3) described above are switched to each other by the control for switching the audio signal transmitted to the transformer 50-2. That is, by switching the audio signal transmitted to the transformer 50-2 from one of the audio signal R and the audio signal L to the other, the electrostatic speaker 1 mixes different sounds such as background music and advertising phrases. You can switch the listening position. The ability to switch this position also means that the size of a region where different sounds can be heard independently can be changed.

  Further, by switching the audio signal transmitted to the transformer 50-2 from the audio signal R or the audio signal L to the audio signal M indicating silence, the electrostatic speaker 1 can be heard with a mixture of background music and advertising phrases. It is possible to set the silent area without the position. When the silent region is set, the electrostatic speaker 1 has a region where the sound of the sound signal R can be heard at a constant volume from the origin O shown in FIG. There is a region where the volume of the sound generated by the audio signal R gradually decreases, and a silent region is reached. Further, when proceeding further in the Y-axis positive direction, there is a region where the volume of the sound by the audio signal L gradually increases, and the sound by the audio signal L reaches an area where it can be heard at a constant volume. In other words, the electrostatic speaker 1 can present the sound based on the sound signal R and the sound based on the sound signal L separately, and can change each sound volume. Then, by switching the audio signal transmitted to the transformer 50-2 from the audio signal M indicating silence to the audio signal R or the audio signal L, the electrostatic speaker 1 can be heard with a mixture of background music and advertising phrases. A position can appear.

  Therefore, according to the electrostatic speaker 1 described above, a plurality of types of sound can be presented according to the contents of the advertising medium (for example, the contents of a plurality of sounds and the contents of images), the aim of the advertisement, the installation environment, and the like. This method can be executed in a plurality of modes by one electrostatic speaker.

[Modification]
The contents of the above-described embodiment may be modified as follows. Each modification shown below may be implemented in combination as necessary.

(Modification 1)
In the above-described embodiment, the electrodes 20-1, 20-2, and 20-3 are fixed to the spacer 30 with an interval so as not to contact each other, but an insulator is disposed between the electrodes to be adjacent to each other. The electrodes may not be in contact with each other. According to this configuration, the electrostatic speaker 1 is not short-circuited because the electrodes are not in contact with each other and are arranged so as to be adjacent to each other via the insulator.

(Modification 2)
In the above-described embodiment, the electrodes 20-1, 20-2, and 20-3 are formed of a conductive metal, but may be a cloth woven of conductive threads. Moreover, the spacer 30 provided between the electrodes 20-1, 20-2, 20-3 and the vibrating body 10 may be formed of a flexible material. In this case, the spacer 30 has flexibility and insulation, and is a separation member for separating the vibrating body 10 and the electrode 20 to form an air layer between the vibrating body 10 and the electrode 20. . The spacer 30 has a rectangular shape when viewed from the Z-axis direction. The length of the spacer 30 in the X-axis direction is the same as the length of the vibrating body 10 in the X-axis direction, and the length of the spacer 30 in the Y-axis direction is the same as the length of the vibrating body 10 in the Y-axis direction. According to this configuration, the electrostatic loudspeaker 1a can be freely deformed, for example, a curved shape or a bent shape.

(Modification 3)
In the embodiment described above, the comb teeth 20-B1 to B3 of the electrode 20-1, the comb teeth 20-D1 to D3 of the electrode 20-2, the comb teeth 20-E1 to E3 of the electrode 20-2, and The comb-tooth portions 20-G1 to G3 of the electrode 20-3 have a rectangular shape as viewed from the positive direction of the Z axis, but may have a shape other than a rectangle. FIG. 8 is a diagram illustrating the shape and sound pressure of the electrode 20 and the vibrating body 10 in this modification. For example, as shown in FIG. 8 (a), the comb tooth portion of the electrode 20-1b instead of the electrode 20-1 described above, the comb tooth portion of the electrode 20-2b instead of the electrode 20-2 described above, and the electrode described above The comb-tooth portion of the electrode 20-3b instead of 20-3 may have a triangular shape as viewed from the positive direction of the Z-axis. In FIG. 8 (a), the portions with wavy lines indicate that the length of each component in the Y-axis direction is omitted.

  In this case, the width of the comb tooth portion of the electrode 20-1b gradually decreases as the distance from the base portion increases, and the width of the comb tooth portion of the electrode 20-2b gradually increases as the distance from the base portion increases. Get smaller. The width here is a direction perpendicular to the protruding direction and parallel to the vibration surface of the vibrating body 10. Further, in this case, in the vibrating body 10, the portion between the comb tooth portion of the electrode 20U-1b and the comb tooth portion of the electrode 20L-1b also has a triangular shape when viewed from the positive direction of the Z axis. This portion is referred to as a first comb tooth region 11-Bb. Similarly, in the vibrating body 10, a portion between the comb tooth portion of the electrode 20U-2b and the comb tooth portion of the electrode 20L-2b also has a triangular shape when viewed from the positive direction of the Z axis. This portion is defined as a second comb tooth region 11-Db. In the vibrating body 10, the length of the first comb tooth region 11-Bb and the second comb tooth region 11-Db in the Y-axis direction is L2, and other portions (the first base region 11-Ab and the second base portion). The length of the region 11-Cb) in the Y-axis direction is L1 and L3 in this order in the Y-axis positive direction. A voltage corresponding to the audio signal R is applied to the electrodes 20U-1b and 20L-1b, and a voltage corresponding to the audio signal M is applied to the electrodes 20U-2b and 20L-2b. In this case, the sound pressure of the sound generated from the vibrating body 10 will be described with reference to FIG. The coordinates Y1 to Y5 are the same as those shown in FIG.

  In FIG. 8B, the horizontal axis represents the position (mm) in the positive direction of the Y axis from the origin O of the vibrating body 10 (here, the lower right corner of FIG. 8A), and the vertical axis is obtained at that position. It represents the sound pressure (decibel) of the sound that can be. In the region from the origin O to the coordinate Y1 of the vibrating body 10, only the sound pressure Rα of the sound having a certain magnitude corresponding to the sound signal R can be obtained. In the region from the coordinate Y2 to the coordinate Y3 of the vibrating body 10, only the sound pressure Mα of the sound corresponding to the audio signal M can be obtained. And in the area | region from the coordinate Y1 to the coordinate Y2 of the vibrating body 10, since the 1st comb-tooth area | region 11-Bb exists first, the sound pressure of the sound according to the audio | voice signal R can be obtained.

  Here, as illustrated in FIG. 8A, the area of the first comb tooth region 11 -Bb gradually decreases from the coordinate Y <b> 1 of the vibrating body 10 toward the positive direction of the Y axis, and the coordinate of the vibrating body 10. It becomes 0 at Y2. Accordingly, the sound pressure of the sound corresponding to the sound signal R that is substantially proportional to the area of the first comb tooth region 11-Bb is the sound pressure Rα at the coordinate Y1 of the vibrating body 10, but the coordinate from the coordinate Y1 of the vibrating body 10 is coordinated. It gradually decreases as it goes to Y2, and the sound pressure becomes 0 at the coordinate Y2 of the vibrating body 10. Furthermore, in the coordinate Y1 to the coordinate Y2 of the vibrating body 10, since not only the first comb tooth region 11-Bb but also the second comb tooth region 11-Db exists, the sound corresponding to the sound signal M is sounded. Pressure can also be obtained. Here, as shown in FIG. 8A, the area of the second comb tooth region 11-Db gradually decreases from the coordinate Y2 of the vibrating body 10 toward the negative Y-axis direction, and the coordinate of the vibrating body 10 It becomes 0 in Y1. Accordingly, the sound pressure of the sound corresponding to the sound signal M that is substantially proportional to the area of the second comb-tooth region 11-Db is the sound pressure Mα at the coordinate Y2 of the vibrating body 10, but from the coordinate Y2 of the vibrating body 10 to the coordinate It gradually decreases as it goes to Y1, and the sound pressure becomes 0 at the coordinate Y1 of the vibrating body 10.

  In the electrostatic speaker 1b, the sound pressure of sound is constant in the region from the origin O to the coordinate Y1, the region from the coordinate Y2 to the coordinate Y3, and the region from the coordinate Y4 to the coordinate Y5. It is. On the other hand, since the electrostatic speaker 1b includes the electrodes 20-1b and 20-2b, in the region from the coordinate Y1 to the coordinate Y2 of the vibrating body 10, sound corresponding to the audio signal M and the audio signal R can be obtained. Sound pressure can be changed gradually. Similarly, since the electrostatic speaker 1b includes the electrodes 20-2b and 20-3b, sound corresponding to the audio signal M and the audio signal L in the region from the coordinate Y3 to the coordinate Y4 of the vibrating body 10 is obtained. The sound pressure can be changed gradually.

  In this modification, as shown in FIG. 8A, the comb-tooth portions of the electrodes 20-1b, 20-2b, and 20-3b have a triangular shape when viewed from the positive direction of the Z axis. The shape of the comb tooth portion is not limited to this. As the distance from the base portion increases, the width of the comb-teeth portion only needs to be gradually reduced. For example, it may have a curved structure like a waveform.

(Modification 4)
In the embodiment described above, the comb teeth 20-B1 to B3 of the electrode 20-1, the comb teeth 20-D1 to D3 of the electrode 20-2, the comb teeth 20-E1 to E3 of the electrode 20-2, and The plurality of cut portions or protruding portions in the comb tooth portions 20-G1 to G3 of the electrode 20-3 have the same length in the Y-axis direction, but have different lengths in the Y-axis direction. Also good. For example, as shown in FIG. 9, three notches of the comb-tooth portion 20-Bc of the electrode 20-1c replacing the electrode 20-1 described above, and the comb-tooth portion of the electrode 20-2c replacing the electrode 20-2 described above. The respective lengths of the 20-Dc three cuts in the Y-axis direction may be gradually shortened toward the X-axis positive direction. Note that FIG. 9 illustrates a comb-tooth portion combined between an electrode 20-1c instead of the electrode 20-1 and an electrode 20-2c instead of the electrode 20-2, but the electrode 20-2 and the electrode 20- The same applies to the comb-tooth portion combined with 3.

  The electrostatic speaker 1c provided with the electrodes 20-1c and 20-2c is attached to a wall or the like so that the positive direction of the X-axis of the electrodes 20-1c and 20-2c is upward. Different sounds can be generated depending on the height of the ear. For example, for a short child, it is desired to maintain the mixed state of the audio signal M and the audio signal R for a long time, while for the tall adult, the audio signal M and the audio signal R are mixed. It is suitable for use scenes where the state only needs to be maintained for a short period.

(Modification 5)
In the embodiment described above, the comb-tooth portions 20-B1 to B3 of the electrode 20-1 and the comb-tooth portions 20-D1 to D3 of the electrode 20-2 are spaced apart so as not to contact each other in an intricate state. It was fixed to the spacer 30. Further, the comb-tooth portions 20-E1 to E3 of the electrode 20-2 and the comb-tooth portions 20-G1 to G3 of the electrode 20-3 are fixed to the spacer 30 with an interval so as not to contact each other in an intricate state. It had been. However, the number of comb teeth portions of the electrode 20-1, the number of comb teeth portions of the electrode 20-2, and the number of comb teeth portions of the electrode 20-3 are not limited thereto. For example, as shown in FIG. 10A, an electrode 20-1d that replaces the electrode 20-1 described above has a base 20-Ad (first electrode portion) and a base 20-Ad that faces the electrode 20-2d. The electrode 20-2d, which replaces the electrode 20-2 described above, has a base portion 20-Cd (third electrode portion) and a base portion. What is necessary is just to have the comb-tooth part 20-Dd (4th electrode part) which protrudes toward 20-1d from 20-Cd. Further, it is only necessary that the comb-tooth portion 20-Dd is disposed at a position between the two comb-tooth portions 20-Bd in the electrode group on the same side as viewed from the vibrating body 10.

  In other words, the adjacent electrode 20-1d and electrode 20-2d only need to be arranged so that the comb-tooth portion protruding from the other is sandwiched between the two comb-tooth portions protruding from either one. In this case, as shown to Fig.10 (a), the one comb-tooth part of the other electrode pinched | interposed by the two comb-tooth parts which protrude from one electrode may be sufficient. In addition, although the comb-tooth part combined between the electrode 20-1d substituted for the electrode 20-1 and the electrode 20-2d substituted for the electrode 20-2 was demonstrated, it is between the electrode 20-2 and the electrode 20-3. The same applies to the comb-tooth portion to be combined.

  Furthermore, the interval between the comb teeth of the electrode 20-1 and the comb teeth of the electrode 20-2 may not be uniform. For example, as shown in FIG. 10B, an electrode 20-1e that replaces the electrode 20-1 described above includes a base portion 20-Ae and a comb tooth portion 20 that protrudes from the base portion 20-Ae toward the electrode 20-2e. -B1e, 20-B2e, and an electrode 20-2e that replaces the electrode 20-2 described above includes a base portion 20-Ce and a comb tooth portion 20 that protrudes from the base portion 20-Ce toward the electrode 20-1e. -D1e, 20-D2e. The comb-tooth portions 20-B1e and 20-B2e and the comb-tooth portions 20-D1e and 20-D2e have a rectangular shape when viewed from the positive direction of the Z-axis, and the lengths in the X-axis direction and the Y-axis direction are respectively. The same. The spacing in the X-axis direction between the comb-tooth portion 20-B1e and the comb-tooth portion 20-D1e is the same as the spacing in the X-axis direction between the comb-tooth portion 20-B2e and the comb-tooth portion 20-D2e. It is shorter than the interval in the X-axis direction between B1e and the comb tooth portion 20-D2e. The portion of the vibrator 10 that is not sandwiched between the electrode 20U-1e and the electrode 20L-1e, the electrode 20U-2e, and the electrode 20L-2e (hereinafter, between the comb-tooth portion 20-B1e and the comb-tooth portion 20-D2e) The void portion 13) does not vibrate and generate sound. The electrostatic speaker 1e including the electrode 20-1e and the electrode 20-2e configured as described above can adjust the sound pressure of the sound to be output by providing the gap portion 13. For example, it is desired that the sound is not heard from a person who is in a position facing the gap 13 while the sound is heard from a person who is not located in a position facing the gap 13. It is suitable for the usage scene. In addition, although the comb-tooth part combined between the electrode 20-1e which replaces the electrode 20-1 and the electrode 20-2e which replaces the electrode 20-2 has been described, between the electrode 20-2 and the electrode 20-3 The same applies to the comb-tooth portion to be combined. In addition, the number of comb teeth protruding from the two adjacent electrodes 20 may be one. Even in this case, for example, from the root to the tip of the comb-tooth portion protruding from one electrode 20 is along the tip to the root of the comb-tooth portion protruding from the other electrode 20, and on this boundary line This is because the sound derived from each electrode 20 is mixed.

(Modification 6)
In the embodiment described above, the electrodes 20-1, 20-2, 20-3 are arranged so as to sandwich one vibrating body 10, but each of the electrodes 20-1, 20-2, 20-3 is disposed. The sandwiched vibrators may be separated from each other. FIG. 11 is a perspective view showing an appearance of an electrostatic speaker 1f according to this modification. As shown in FIG. 11, the electrostatic speaker 1f includes a sound emitting unit 40-1 corresponding to a first electrostatic sound emitting unit and a sound emitting unit 40-2 corresponding to a second electrostatic sound emitting unit. And a sound emitting unit 40-3 corresponding to a third electrostatic sound emitting unit. The sound emitting unit 40-1, the sound emitting unit 40-2, and the sound emitting unit 40-3 are each configured as an electrostatic speaker that can function alone. That is, each sound emitting unit is configured to be separated and independent from each other, with the vibrating body and the electrode as a pair.

  First, the configuration of each part of the electrostatic speaker 1f will be described. The vibrating bodies 10-1f, 10-2f, and 10-3f are obtained by forming a conductive metal conductive film on the surface of a transparent film such as PET or PP. Since the vibrating bodies 10-1f, 10-2f, and 10-3f have a thin film shape with a thickness of about several μm, they are freely deformed when subjected to an external force. The vibrating body 10-1f is the same as the shape of the electrode 20-1 when viewed from the Z-axis direction, the vibrating body 10-2f is the same as the shape of the electrode 20-2 when viewed from the Z-axis direction, and the vibrating body 10-3f is The shape of the electrode 20-3 is the same as seen from the Z-axis direction. As long as the spacers 30U-1f, 30L-1f, 30U-2f, 30L-2f, 30U-3f, and 30L-3f are formed of a material having insulating properties and sound transmission properties, sponge-like, sheet-like, non-woven fabric, etc. It can take a variety of forms. The spacers 30U-1f and 30L-1f are the same as the shape of the electrode 20-1 when viewed from the Z-axis direction, and the spacers 30U-2f and 30L-2f are the same as the shape of the electrode 20-2 when viewed from the Z-axis direction. The spacers 30U-3f and 30L-3f have the same shape as the electrode 20-3 when viewed from the Z-axis direction.

  Next, the structure of the electrostatic speaker 1f will be described. The vibrating body 10-1f is disposed between the spacer 30U-1f and the spacer 30L-1f. The vibrating body 10-1f is fixed to the spacers 30U-1f and 30L-1f by applying an adhesive with a width of several mm inward from the X-axis direction edge and the Y-axis direction edge. A portion of the vibrating body 10-1f where the adhesive is not applied is not fixed to the spacer 30U-1f and the spacer 30L-1f. The electrode 20U-1 is fixed to the spacer 30U-1f so as to face the electrode 20L-1 with the vibrating body 10-1f interposed therebetween. The electrode 20L-1 has the electrode 20U- with the vibrating body 10-1f interposed therebetween. 1 is fixed to the spacer 30L-1f in a state of facing 1. The electrode 20-1 has a base 20-A and a plurality of comb-tooth portions 20-B1 to B3 protruding from the base 20-A. The electrode 20U-2 is fixed to the spacer 30U-2f in a state of facing the electrode 20L-2 with the vibrating body 10-2f interposed therebetween. The electrode 20L-2 is an electrode with the vibrating body 10-2f sandwiched therebetween. It is fixed to the spacer 30L-2f in a state facing 20U-2. The electrode 20-2 has a base 20-C and one or more comb-tooth portions 20-D1 to D3 protruding from the base 20-C.

  In the electrostatic speaker 1f configured as described above, the comb-tooth portions 20-B1 to B3 protrude toward the electrode 20-2, and the comb-tooth portions 20-D1 to D3 protrude toward the electrode 20-1. The sound emitting part 40-1 and the sound emitting part 40-2 can be supported in a state where the comb tooth part 20-D is disposed at a position sandwiched between the two comb tooth parts 20-B. In addition, although the comb-tooth part combined between the electrode 20-1f substituted for the electrode 20-1 and the electrode 20-2f substituted for the electrode 20-2 was demonstrated, it is between the electrode 20-2 and the electrode 20-3. The same applies to the comb-tooth portion to be combined. That is, in the electrostatic speaker 1f, the comb-tooth portions 20-E1 to E3 protrude toward the electrode 20-3, the comb-tooth portions 20-G1 to G3 protrude toward the electrode 20-2, and two comb-tooth portions The sound emitting unit 40-2 and the sound emitting unit 40-3 can be supported in a state where the comb-tooth portion 20-G is disposed at a position sandwiched by 20-E.

(Modification 7)
In the embodiment described above, the electrode 20-2 has the comb-tooth portions 20-D1 to D3 that are the fourth comb-tooth portions protruding to the electrode 20-1, and the fifth comb protruding to the electrode 20-3. Although it has the comb-tooth part 20-E1-E3 which is a tooth | gear part, only one of the above may be sufficient as the comb-tooth part which the electrode 20-2 has. FIG. 12 is a diagram showing the appearance of the electrostatic speakers 1g and 1h in this modification. As shown in FIG. 12, the electrode 20-2 has comb-tooth portions 20-D1g, 20-D2g, and 20-D3g protruding toward the electrode 20-1. These are arranged in a state of being engaged with comb-tooth portions 20-B1g, 20-B2g, and 20-B3g protruding from the electrode 20-1 toward the electrode 20-2.

On the other hand, in the electrode 20-2, the electrode 20-3 side has a section Eg1 parallel to the X axis, and does not have a protruding portion. A voltage corresponding to the audio signal R is applied to the electrode 20-1, and a voltage corresponding to the audio signal L is applied to the electrode 20-3. Even in this configuration, the voltage applied to the electrode 20-2 in the state of case I in FIG. 5B is made the same as the voltage applied to the electrode 20-1 by controlling the switch described above. If there is, the audio signal R and the audio signal L can be heard separately from the segment Eg1, so that the listener listens separately to the sound indicated by the audio signal R and the sound indicated by the audio signal L, and the mixed sound. Never listen.
Further, if the voltage applied to the electrode 20-2 in the state of case III in FIG. 5B is controlled to be the same as the voltage applied to the electrode 20-3 by controlling the above-described switch, the meshing is performed. Since the audio signal R and the audio signal L are mixed and heard at the comb tooth portion, the listener listens to a sound in which the sound indicated by the audio signal R and the sound indicated by the audio signal L are mixed.
If the voltage corresponding to the sound signal M indicating silence is applied to the electrode 20-2 by controlling the above-described switch to the case II in FIG. 5B, the sound signal R and sound A region where sound cannot be heard is generated between regions where the signal L can be heard independently.
In addition, the structure of the electrostatic speaker provided with the 4th comb-tooth part and the 5th comb-tooth part in embodiment is represented as follows.

A vibrating body having electrical conductivity;
First, second and third electrodes facing the vibrating body;
An insulating spacing member that separates the vibrating body and each of the electrodes;
A voltage according to a first audio signal is applied to the first electrode, and a voltage according to a second audio signal different from the first audio signal is applied to the third electrode. Then, a voltage corresponding to any of the first audio signal, the second audio signal, and a third audio signal indicating a sound whose volume is less than a predetermined threshold is selected for the second electrode. Voltage applying means to be applied,
The first electrode includes a first electrode portion and a second electrode portion having a shape protruding from the first electrode portion toward the second electrode,
The second electrode includes a third electrode portion, a fourth electrode portion having a shape protruding from the third electrode portion toward the first electrode, and the third electrode portion to the third electrode portion. A fifth electrode portion having a shape protruding toward the electrode of
The third electrode is disposed at a position where the second electrode is sandwiched between the third electrode and the sixth electrode portion, and the sixth electrode portion and the sixth electrode portion to the second electrode. And a seventh electrode portion having a shape protruding toward the
In the second electrode portion and the fourth electrode portion, one portion protruding from one of the electrode portions is sandwiched between two portions protruding from the other electrode portion. Arranged,
In the fifth electrode portion and the seventh electrode portion, one portion protruding from one of the electrode portions is sandwiched between two portions protruding from the other electrode portion. An electrostatic speaker characterized by being arranged.

  In the above-described embodiment, the electrode 20-2 and the electrode 20-1 or the electrode 20-3 are arranged in only the Y-axis direction, but the arrangement direction of the electrodes 20 is not limited to one direction. For example, they may be arranged in a lattice form in two directions, the X-axis direction and the Y-axis direction. Even in this case, three electrodes 20 are arranged in the X-axis direction, and the electrode arranged in the middle of the three electrodes corresponds to the same voltage as one of the electrodes at both ends or an audio signal M indicating silence. It is only necessary to be able to apply a high voltage. Further, the direction in which the electrodes 20 are arranged is not limited to a straight line. For example, the direction in which the electrodes 20 are arranged may be a sector shape or a spiral shape.

  In the above-described embodiment, the number of electrodes 20 arranged is three, but may be four or more. In this case, among the four or more electrodes 20 arranged side by side, the three adjacent electrodes 20 are the above-described electrodes 20-1, 20-2, 20-3, that is, the first, second, and third electrodes. It only has to be configured.

(Modification 8)
In the embodiment described above, the electrostatic speaker 1 has a push-pull configuration in which the vibrating body 10 is sandwiched between a pair of electrodes, but the configuration of the electrostatic speaker 1 is not limited to this configuration. . For example, a single-type configuration in which one spacer 30 is sandwiched between a pair of conductive films facing each other, one of the conductive films is used as an electrode, and the other conductive film is used as a vibrator.

(Modification 9)
In the embodiment described above, the audio signal M input to the input unit 60-2 is an audio signal representing a sound whose volume is less than a predetermined threshold, but the audio signal input to the input unit 60-1 The audio signal may be a mixture of R and the audio signal L input to the input unit 60-3. Further, the control unit 80 may select any one of the mixed audio signal and the audio signal indicating silence as the audio signal M. In this case, the audio signal R and the audio signal L may be mixed at a determined ratio. For example, the sound pressures of the audio signal R and the audio signal L are adjusted by predetermined coefficients (α, β) so that the sound pressure becomes (Lα + Rβ), and mixed, and the mixed audio signal is converted into an audio signal. M may also be used.

  That is, the voltage comprised including the control part 80 shown in FIG.4 and FIG.5, input part 60-1,60-2,60-3, and transformer 50-1,50-2,50-3. The applying means applies a voltage according to the audio signal R (first audio signal) to the electrode 20-1 (first electrode), and to the electrode 20-3 (third electrode). A voltage corresponding to an audio signal L (second audio signal) different from the audio signal R is applied, and the audio signal R, the audio signal L, and the volume are predetermined threshold values for the electrode 20-3 (second electrode). A voltage may be selected and applied according to any of the third audio signal indicating less than the sound and the fourth audio signal obtained by synthesizing the audio signal R and the audio signal L at a predetermined ratio.

  According to this configuration, in the state of case II shown in FIG. 6, the listener can hear a sound corresponding to the audio signal M obtained by mixing the audio signal L and the audio signal R in the region from the coordinate Y1 to the coordinate Y4. Can do.

(Modification 10)
In the above-described embodiment and modification, the electrostatic speaker 1 that emits sound based on the input audio signal is described. However, the configuration of the electrostatic speaker 1 is a sound collection device such as an electrostatic microphone. You may use for. That is, an electrostatic speaker that converts an electric signal into sound (sound wave) may be applied to an electrostatic microphone that converts sound (sound wave) into an electric signal. Both the electrostatic speaker and the electrostatic microphone are considered as electrostatic electroacoustic transducers.

  FIG. 13 is a diagram showing an electrical configuration of an electrostatic microphone 1M according to this modification. In the configuration shown in FIG. 13, instead of the input units 60-1, 60-2, and 60-3, output units 61-1, 61-2, and 61-3 (hereinafter referred to as “ Are collectively referred to as “output unit 61”). In this case, the vibrating body 10 is vibrated by ambient sound, and this vibration is converted into an electrical signal between the electrodes 20-1, 20-2, and 20-3. The control unit 80 controls the three switches SW1, SW2, and SW3 shown in FIG. When the control unit 80 turns on only the switch SW2 and turns off the other switches, the circuit enters the state of case II shown in FIG. The electrical signals generated at the electrodes 20-1, 20-2, and 20-3 are individually transmitted to the transformers 50-1, 50-2, and 50-3, and the electrical signals corresponding to the electrical signals are output to the output unit. 6-1, 61-2, and 61-3, respectively. Therefore, the sound wave incident on each electrode 20 in the vibrating body 10 is converted into a separate electric signal and output.

  On the other hand, when the control unit 80 turns on only the switch SW1 and turns off the other switches, the circuit is in the state of case I shown in FIG. At this time, the electric signals generated at the electrodes 20-1 and 20-2 are individually transmitted to the transformers 50-1 and 50-2 and then mixed and output from the output units 61-1 and 61-2. The And the electric signal which generate | occur | produces in the electrode 20-3 is transmitted to the transformer 50-3, and is output from the output part 61-3. Therefore, in the vibrating body 10, the sound in the front direction of the electrode 20-3 is output without being mixed with the sound in the front direction of the electrodes 20-1 and 20-2, but in the front direction of the electrode 20-1. The sound and the sound in the front direction of the electrode 20-2 are mixed and output.

  Similarly, when the control unit 80 turns on only the switch SW3 and turns off the other switches, the circuit enters the state of case III shown in FIG. 5B. As a result, in the vibrating body 10, the sound in the front direction of the electrode 20-1 is output without being mixed with the sound in the front direction of the electrodes 20-2 and 20-3, but the front direction of the electrode 20-2. And the sound in the front direction of the electrode 20-3 are mixed and output.

In this modification, the above-described switches SW1, SW2, SW3 and the control unit 80 function as output selection means in the present invention.
When the impedance of the transformers 50-1, 50-2, 50-3 is low, the electric signals output from the output units 61-1, 61-2, 61-3 are amplified by amplifiers, respectively. May be.

  That is, according to the configuration of this modified example, the size of the region where sound is collected by the vibrating body 10 can be adjusted.

DESCRIPTION OF SYMBOLS 1 ... Electrostatic speaker (electrostatic electroacoustic transducer), 10 ... Vibrating body, 20 ... Electrode, 20-A, 20-C, 20-F ... Base, 20-B, 20-D, 20- E, 20-G ... comb tooth part, 30 ... spacer, 40-1, 40-2, 40-3 ... sound emission part, 50-1, 50-2, 50-3 ... transformer, 60-1, 60 -2, 60-3 ... Input unit, 70 ... Bias power supply, 80 ... Control unit, 90 ... Cover member, 91 ... Advertisement image, 1M ... Electrostatic microphone (electrostatic electroacoustic transducer)

Claims (3)

A first vibrating body having conductivity , a first electrode opposed to the first vibrating body, and an insulating first separation for separating the first electrode and the first vibrating body. A first electrostatic sound emitting unit comprising a member;
A conductive second vibrating body, a second electrode facing the second vibrating body, and an insulating second spacing member that separates the second electrode and the second vibrating body A second electrostatic sound emitting unit comprising:
A conductive third vibrating body, a third electrode facing the third vibrating body, and an insulating third spacing member that separates the third electrode and the third vibrating body A third electrostatic sound emitting unit comprising:
A first application unit that applies a voltage according to a first audio signal to the first electrode;
A second application unit that applies a voltage according to a second audio signal different from the first audio signal to the third electrode;
For the second electrode, any one of the first audio signal, the second audio signal, and an audio signal indicating a sound whose volume is less than a predetermined threshold is selected, and the selected audio is selected. A third application unit for applying a voltage according to the signal,
The first electrode includes a first electrode portion and a second electrode portion having a shape protruding from the first electrode portion toward the second electrode,
The second electrode includes a third electrode portion, and a fourth electrode portion having a shape protruding from the third electrode portion toward the first electrode,
A state in which the fourth electrode portion is disposed at a position sandwiched between two of the second electrode portions, or a state in which the second electrode portion is disposed at a position sandwiched between two of the fourth electrode portions; In this way, the first electrostatic sound emitting unit and the second electrostatic sound emitting unit are supported,
The electrostatic speaker is characterized in that the third electrostatic sound emitting unit is disposed at a position sandwiching the second electrostatic sound emitting unit between the third electrostatic sound emitting unit and the first electrostatic sound emitting unit. The greater the distance from the previous SL first electrode portion, the width of the second electrode portion becomes gradually smaller,
It said third distance from the electrode portion increases, electrostatic speaker according to claim 1, wherein a width of the fourth electrode portion is equal to or gradually decreased. A first vibrator having conductivity, the first electrode facing the first vibrator, the first separation of the insulation of separating said and said first electrode first vibrator A first output unit that outputs a first audio signal generated in the first electrode in response to vibration of the first vibrating body;
A conductive second vibrating body, a second electrode facing the second vibrating body, and an insulating second spacing member that separates the second electrode and the second vibrating body A second output unit that outputs a second audio signal different from the first audio signal generated in the second electrode in response to vibration of the second vibrating body;
A conductive third vibrating body, a third electrode facing the third vibrating body, and an insulating third spacing member that separates the third electrode and the third vibrating body A third output unit for outputting a third audio signal different from the first and second audio signals generated in the third electrode in response to vibration of the third vibrating body;
It said first, selects one of the second and third output unit, when selecting the first output unit, the second audio signal is mixed with the first audio signal output to the first output portion Te, wherein when selecting the second output portion, the second the second audio signal without with any mixture of said first and third audio signals output to the output unit, when selecting the third output portion includes an output selecting means for outputting said second audio signal to said third output portion is mixed with the third audio signal With
The first electrode includes a first electrode portion and a second electrode portion having a shape protruding from the first electrode portion toward the second electrode,
The second electrode includes a third electrode portion, and a fourth electrode portion having a shape protruding from the third electrode portion toward the first electrode,
The third electrode is disposed at a position sandwiching the second electrode with the first electrode,
In the second electrode portion and the fourth electrode portion, one portion protruding from one of the electrode portions is sandwiched between two portions protruding from the other electrode portion. An electrostatic microphone characterized by being arranged.

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