JPH11109978A - Sound insulation device - Google Patents

Abstract

(57) [Summary] To provide a sound insulating device that generates a control sound on a path of a transmitted sound and in which the same phase plane of the control sound occurs in a plane. Further, a sound insulation device having a window with good lighting and a wide field of view is obtained. SOLUTION: A microphone 2 is attached to a noise source 6 side of an electrostatic speaker 1 and the electrostatic speaker 1 is attached to the structure plate 4 by a fixture 5 so as to cover the entire surface of the structure plate 4 or a portion requiring sound insulation. The noise generated from the noise source 6 is converted into an electric signal by the microphone 2 and output to the control unit 3. The output signal from the control unit 3 drives the electrostatic speaker 1 to generate a control sound from the electrostatic speaker 1. I do.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound insulation device for suppressing the propagation of noise, and is used, for example, in buildings around airports, railway lines, motorways, and the like.

[0002]

2. Description of the Related Art Noise from airplanes has been a problem in the vicinity of airports that have been nearer to densely populated houses. Therefore, as a sound insulating plate for reducing the transmission of noise into the interior of a house, a double structure plate or the like which passively performs a sound insulating effect by providing an air layer therebetween has been put to practical use. However, the sound insulation properties of this double-structured board are not perfect, and in fact, due to resonance phenomena occurring in the air layer inside the double-structured board, particularly low to mid-range noises penetrate into the house.

For this reason, there has been proposed a sound insulation device capable of suppressing noise from a low frequency range to a high frequency range by actively performing control. FIG. 8 shows, for example,
It is a block diagram of the conventional sound insulation device shown by 149267 gazettes. In the drawing, reference numeral 22 denotes a window face plate, 23 denotes a microphone in the sound receiving space and detects noise transmitted from the window face plate 22, 24 denotes a speaker that radiates sound waves into the sound receiving space, and 25 denotes a sound receiving space. A microphone 26 that is outside and detects noise from a noise source is a drive unit that controls the sound insulation device.

In such a conventional sound insulating device, a sound wave generated from a noise source and transmitted through the window plate 22 and a sound wave generated by driving the speaker 24 by the driving unit 26 interfere with each other. The drive unit 26 is configured to generate a drive signal for the speaker 24 based on noise signals from the microphone 25 outside the sound receiving space and the microphone 23 inside the sound receiving space so that sound input to the microphone 23 inside the sound receiving space is minimized. Has been generated. In addition, since the components of the sound insulation device are not added to the surface of the window plate 22, the lighting of the window and the visibility are secured to some extent.

[0005]

In the above-described conventional sound insulation device, when the sound wave transmitted through the window plate 22 has the same phase in a plane parallel to the window surface, the sound wave is output from the speaker 24. Since the sound waves have the same phase on a spherical surface with a constant radius centered on the speaker 24, the interference results of these sound waves are in a state where the intensity of the sound is spatially distributed. For this reason, there is a problem that even if the transmitted sound can be weakened at a specific position (for example, the position of the microphone 23), the sound receiving space cannot be totally shielded from the transmitted sound. In addition, since the speaker 24 is installed away from the path of the transmitted sound, the element of the distance between the speaker 24 and the path of the transmitted sound also needs to be modeled in the control law.

Further, the size of the opening of the speaker 24 tends to be large in order to improve the characteristics in the low-frequency range, and the size of the embedded portion of the speaker 24 at the periphery of the window becomes large. It is necessary to reduce the size of the window panel, and as a result, the lighting becomes poor and the window panel 22
There was also a problem that the field of view through the camera became narrow.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and provides a sound insulation device that generates a control sound on a path of a transmitted sound and generates the same phase plane of the control sound in a plane. Further, the present invention provides a sound insulation device having a window with good lighting and a wide field of view.

[0008]

According to a first aspect of the present invention, there is provided a sound insulating device based on an electrostatic speaker, a microphone attached to a noise source side of the electrostatic speaker, and an electric signal from the microphone. A control means for controlling the electrostatic loudspeaker to suppress transmitted sound that is incident on the electrostatic loudspeaker from the noise source side and transmitted therethrough.

According to a second aspect of the present invention, there is provided a sound insulating device comprising: a substrate; an electrostatic loudspeaker provided on the substrate; and a noise source side of the electrostatic loudspeaker provided on the substrate. By controlling the microphone and the electrostatic speaker based on an electric signal from the microphone,
Suppression means for suppressing transmitted sound that enters the electrostatic speaker from the noise source side and transmits the electrostatic speaker.

According to a third aspect of the present invention, in the sound insulating device of the first aspect, the electrostatic speaker is provided on an insulating substrate and one main surface of the insulating substrate. A substrate-side electrode, a diaphragm disposed opposite to the substrate-side electrode, and a diaphragm-side electrode provided on the insulating substrate side of the diaphragm, wherein the microphone includes the insulating substrate, A substrate-side electrode provided on the other main surface of the insulating substrate; a diaphragm disposed opposite to the substrate-side electrode; and a diaphragm-side electrode provided on the insulating substrate side of the diaphragm. It is a thing.

According to a fourth aspect of the present invention, in the sound insulating device according to the first aspect of the present invention, one of the electrostatic loudspeaker or the microphone includes an insulating substrate and one of the main components of the insulating substrate. A substrate-side electrode provided on the surface, a diaphragm disposed opposite to the substrate-side electrode, and a diaphragm-side electrode provided on the insulating substrate side of the diaphragm, the electrostatic speaker or The other of the microphones includes the insulating substrate, the substrate-side electrode, a vibration plate disposed to face another main surface of the insulating substrate, and a vibration provided on the insulating substrate side of the vibration plate. It has a plate-side electrode.

According to a fifth aspect of the present invention, in the sound insulating device of the third aspect, the electrostatic speaker or the microphone is provided outside the diaphragm to protect the diaphragm. It has a protective substrate.

According to a sixth aspect of the present invention, there is provided a sound insulating device according to the third aspect, wherein the electrostatic speaker is provided on a side of the diaphragm opposite to the diaphragm side electrode. A diaphragm-side electrode, and a through-hole substrate having a large number of through-holes disposed opposite to the second diaphragm-side electrode;
A second substrate-side electrode provided on the diaphragm side of the substrate with through holes.

According to a seventh aspect of the present invention, there is provided the sound insulating device according to the third aspect of the present invention, wherein the insulating substrate constituting the electrostatic speaker and the microphone, the substrate-side electrode, and the vibration The plate and the diaphragm-side electrode are made of a transparent member.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is an overall configuration diagram of the sound insulation device according to the present embodiment. In FIG. 1, reference numeral 1 denotes an electrostatic loudspeaker having an opening dimension to cover the entire surface of a structural plate 4 described later or a portion requiring sound insulation. 2 is a microphone attached to the noise source side of the electrostatic speaker 1, 3 is a microphone 2
Is a control unit that controls the driving of the electrostatic speaker 1 based on the output signal from the speaker. Reference numeral 4 denotes a structural plate of the building, and the electrostatic speaker 1 and the microphone 2 are mounted on the structural plate 4 by the fixture 5. In addition, the structural plate 4 may be a window panel of a building. Reference numeral 6 denotes a noise source, and noise generated from the noise source is incident on the electrostatic speaker 1 and the structure plate 4. Reference numeral 7 denotes a microphone in the sound receiving space for detecting a transmitted sound and outputting it to the control unit. FIG. 2 is a detailed configuration diagram of the electrostatic speaker 1 and the microphone 2. Reference numeral 8 denotes a substrate, and 9 denotes a substrate-side electrode formed on the main surface of the substrate 8. Reference numeral 10 denotes a vibration plate arranged to face the substrate-side electrode 9,
Reference numeral 11 denotes a diaphragm-side electrode provided on the substrate 8 side of the diaphragm 10. Reference numeral 12 denotes a spacer for stretching the diaphragm 10 and the diaphragm-side electrode 11. The substrate-side electrode 9 and the diaphragm-side electrode 11 are insulated by the spacer 12.

The noise generated from the noise source 6 enters the microphone 2 and the electrostatic speaker 1. Microphone 2
Is incident on the control unit 3 and converted into an electric signal. The control unit 3 drives the electrostatic speaker 1 based on an electric signal from the microphone 2. Electrostatic speaker 1
For example, a constant DC voltage is applied between the substrate-side electrode 9 and the diaphragm-side electrode 11, and when a signal is superimposed on the diaphragm-side electrode 11, a signal is generated between the substrate-side electrode 9 and the diaphragm-side electrode 11. The electric charge fluctuates, and the fluctuation of the electric charge fluctuates the Coulomb force acting between the electrodes, and the diaphragm 10 vibrates to generate a sound wave. The electrostatic speaker 1 is controlled by a signal from the control unit 3.
In this case, an output sound wave having the same amplitude and opposite phase as the transmitted sound that is incident on and transmitted from the noise source 6 to the electrostatic speaker 1 is generated, and the transmitted sound interferes with the output sound wave of the electrostatic speaker 1. Sound waves output from the electrostatic loudspeaker 1 are generated in the same phase on the plate surface of the diaphragm 10 of the electrostatic loudspeaker 1 and are the same on a plane parallel to the surfaces of the electrostatic loudspeaker 1 and the structure plate 4. Cancels transmitted sound having a phase over the entire surface. The sound wave output from the electrostatic speaker 1 is generated on the path of the transmitted sound,
In the control law of the control unit 3, it is not necessary to model the distance between the electrostatic speaker 1 and the path of the transmitted sound to be controlled. If system parameters change due to environmental conditions such as temperature changes and transmitted sound remains in the sound receiving space, the transmitted sound is detected by the microphone 7 and fed back to the control unit 3 to output the output signal of the microphone 7. Is controlled to be minimized.

Embodiment 2 FIG. In the first embodiment, the microphone 2 is attached to the electrostatic speaker 1 and the microphone 2 is installed on the structural plate of the building. However, as shown in FIG. 3, the electrostatic speaker 1 and the microphone 2 are attached to the substrate. It may be configured to be fitted into a frame of a building. In FIG. 3, reference numeral 13 denotes a substrate serving as a structural plate or a window plate of a building, on which an electrostatic speaker 1 and a microphone 2 are attached. The microphone 2 is arranged on the noise source 6 side with respect to the electrostatic speaker 1. Reference numeral 14 denotes a building frame into which the substrate 13, the electrostatic speaker 1, and the microphone 2 are fitted.

In FIG. 3, noise from the noise source 6 enters the microphone 2 and the substrate 13. The control unit 3 drives the electrostatic speaker 1 based on the signal detected by the microphone 2 to generate a sound wave. The output sound wave and the transmitted sound that enters the substrate 13 and transmits through the electrostatic speaker 1 interfere with each other.
As in the first embodiment, when transmitted sound remains in the sound receiving space, the transmitted sound remaining in the microphone 7 is detected and fed back to the control unit 3 to minimize the output signal of the microphone 7. Is controlled to

Embodiment 3 In the first embodiment, the microphone 2 is attached to the electrostatic speaker 1. However, when an electrostatic microphone is used as the microphone 2, as shown in FIG. Alternatively, both an electrostatic speaker and an electrostatic microphone may be formed. In FIG. 4, reference numeral 15 denotes an insulating substrate that fixes and insulates a substrate-side electrode 9a and a substrate-side electrode 9b described later, and 9a and 9b denote insulating substrates 15a and 9b.
Substrate-side electrodes provided on both main surfaces of 10a and 10a.
Reference character b denotes a diaphragm disposed opposite to the substrate-side electrode 9a and the substrate-side electrode 9b. Reference numerals 11a and 11b denote diaphragm-side electrodes provided on the diaphragm 10a and the diaphragm 10b, respectively, on the insulating substrate 15 side. Reference numeral 12a denotes a spacer for stretching the diaphragm 10a and the diaphragm-side electrode 11a, and the substrate-side electrode 9a and the diaphragm-side electrode 11a are insulated by the spacer 12a. Reference numeral 12b denotes a spacer for stretching the diaphragm 10b and the diaphragm-side electrode 11b, and the substrate-side electrode 9b and the diaphragm-side electrode 1b.
1b is insulated by the spacer 12b.

In FIG. 4, the electrostatic speaker includes an insulating substrate 15 for fixing the substrate-side electrode 9a, a substrate-side electrode 9a,
It is composed of a diaphragm 10a and a diaphragm-side electrode 11a. The electrostatic microphone includes an insulating substrate 15 for fixing the substrate-side electrode 9b, the substrate-side electrode 9b, the diaphragm 10b, and the diaphragm-side electrode 11b. When noise from the noise source enters the diaphragm 10b, the diaphragm 10b and the diaphragm-side electrode 11b vibrate, and the distance between the diaphragm 10b and the substrate-side electrode 9b fixed to the insulating substrate 15 changes. A change in the distance between the substrate-side electrode 9b and the diaphragm-side electrode 11b causes a change in the capacitance between the electrodes. This change in the capacitance of the capacitor is detected as an electric signal by, for example, applying a constant DC voltage between the substrate-side electrode 9b and the diaphragm-side electrode 11b, and changing the charge according to the change in the capacitance of the capacitor. . As described above, the electrostatic microphone and the electrostatic speaker are
Since the insulating substrate 15 is configured as a common substrate, the installation space of the sound insulation device can be further reduced as compared with the case where the insulating substrate 15 is configured by an electrostatic speaker and an electrostatic microphone each having a fixed plate. The insulating substrate 15 may be a structural plate of a building. In this case, the insulating substrate 15 is used by being fitted into a frame of the building (the same applies to Embodiments 4 to 6 described later). FIG. 4 shows a configuration in which the vibration plate 10 b is disposed so as to face the entire surface of the insulating substrate 15, but the size may be reduced as long as it is sufficiently sensitive to noise incident from the noise source 6. In this case, the substrate-side electrode 9b, the diaphragm 10b, and the diaphragm-side electrode 11b are partially formed on the surface of the insulating substrate 15 (the same applies to the later-described fourth to sixth embodiments). .

Embodiment 4 FIG. In the third embodiment, the substrate-side electrode 9a and the substrate-side electrode 9b are provided on both main surfaces of the insulating substrate 15, but when the insulating substrate 15 is thin, as shown in FIG. The configuration may be such that the substrate-side electrode 9a and the substrate-side electrode 9b are shared as the substrate-side electrode 9. The electrostatic speaker includes an insulating substrate 15 for fixing the substrate-side electrode 9, the substrate-side electrode 9, the diaphragm 10a, and the diaphragm-side electrode 11a. The electrostatic microphone includes an insulating substrate 15, a substrate-side electrode 9, a diaphragm 10b, and a substrate-side electrode 11b. The wiring to the substrate-side electrode 9 is grounded, for example, so that the capacitance of the capacitor between the substrate-side electrode 9 and the diaphragm-side electrode 11b in the electrostatic microphone is independent of the diaphragm-side electrode 11a. Become.
The Coulomb force generated in the electrostatic loudspeaker changes by an amount corresponding to the change in the charge on the substrate-side electrode 9 that is excited to the diaphragm-side electrode 11b by the operation of the electrostatic microphone. By integrating, the electric charge on the substrate-side electrode 9 excited on the diaphragm-side electrode 11b is estimated, and by subtracting this amount, the diaphragm-side electrode is generated so that a desired Coulomb force is generated in the electrostatic speaker. The signal to be superimposed on 11a is determined. Inside the electrostatic microphone, the capacitance of the capacitor including the insulating substrate 15 is determined. The insulating substrate 15 and the diaphragm-side electrode 11b
Is shorter, the thickness of the configuration including the insulating substrate, the electrostatic microphone, and the electrostatic speaker can be reduced. Although the insulating substrate 15 is disposed between the substrate-side electrode 9 and the diaphragm-side electrode 11b in FIG. 4, the insulating substrate 15 may be disposed between the substrate-side electrode 9 and the diaphragm-side electrode 11a. Good.

Embodiment 5 In the third embodiment, the electrostatic microphone and the electrostatic loudspeaker are formed on the insulating substrate 15, but as shown in FIG. 6, the substrate 17 is mounted on the diaphragm 10b by the spacer 16 as shown in FIG. May be added. If the electrostatic microphone is exposed to the outside of the building,
Protects the diaphragm 10b from ambient conditions, especially from contamination by outdoor rain and deformation by wind. In addition, since the substrate 17 and the insulating substrate 15 have a double-plate configuration, the sound insulation is improved. Note that a configuration may be adopted in which a substrate is attached to the side of the diaphragm 10a opposite to the insulating substrate 15, and in this case, the diaphragm 10a is protected against a load applied due to contact with another object indoors.

Embodiment 6 FIG. In the third embodiment, the electrostatic speaker is constituted by one capacitor, but as shown in FIG. 7, a push-pull electrostatic speaker may be further provided by adding an electrode to the electrostatic speaker. FIG.
In the figure, reference numeral 18 denotes a diaphragm-side electrode provided on the side of the diaphragm 10a opposite to the diaphragm-side electrode 11a; This is a substrate-side electrode provided on the diaphragm 10a side. The substrate 19 with the through hole and the substrate-side electrode 20 are
1 attaches to the insulating substrate 15 side. The diaphragm-side electrode 18 and the substrate-side electrode 20 are insulated by a spacer 21.

With the above-described configuration, the electrostatic loudspeaker has electric charges at two portions, that is, the portion composed of the substrate side electrode 9a and the diaphragm side electrode 11a and the portion composed of the diaphragm side electrode 18 and the substrate side electrode 20. And a push-pull electrostatic loudspeaker that generates Coulomb force, thereby improving the loudspeaker characteristics in the low frequency range.

Embodiment 7 In the third embodiment, the insulating substrate 15 is formed of an opaque material.
In the present embodiment, components such as the insulating substrate 15 are made of a transparent material in order to apply the sound insulating device to the window. In FIG. 3, the insulating substrate 15 is a transparent insulating substrate. As a material for a transparent insulating substrate,
A glass plate or a transparent resin plate such as acrylic is used. Further, the substrate side electrode 9a, the substrate side electrode 9b, the diaphragm side electrode 1
1a, the diaphragm-side electrode 11b is a transparent electrode. As a material for the transparent electrode, a metal oxide such as tin oxide-indium oxide is used. Further, the diaphragm 10a, the diaphragm 10
b is a transparent diaphragm. As a material of the transparent diaphragm, a transparent film such as polyester or vinyl chloride such as polyethylene terephthalate, a thin resin plate, or the like is used.

By using a transparent material as described above, the sound insulating device can be attached to a window and used. Only the spacers 12a and 12b are provided on the peripheral edge of the insulating substrate 15, and light is taken from most of the surface of the insulating substrate 15 and a wide field of view is secured. If the material of the spacers 12a and 12b is made of a transparent material, the daylighting property is further improved and the field of view is widened. The insulating substrate 15 may be used as a window plate of a building,
In this case, it is used by being fitted into a frame of a building.

[0027]

According to the present invention, since the control sound from the sound insulating device is emitted from the electrostatic speaker, the control sound has the same phase on the diaphragm surface in the electrostatic speaker, and the electrostatic speaker The transmitted sound transmitted in the same phase on the plane can be shielded in the entire area of the plane. Further, since the control sound can be directly generated on the path through which the transmitted sound is transmitted, the distance between the control sound generation source and the sound field of the transmitted sound to be controlled is controlled without considering the control law. be able to.

One insulating substrate is used as a common substrate, and a substrate-side electrode, a diaphragm, and a diaphragm-side electrode are arranged on both sides of the insulating substrate to form an electrostatic speaker and an electrostatic microphone. With this configuration, it is possible to reduce the number of substrates conventionally attached to each of the electrostatic speaker and the electrostatic microphone.

The number of electrodes can be reduced by employing a configuration in which the substrate-side electrode provided on one main surface of the insulating substrate also serves as the substrate-side electrode of the electrostatic speaker and the substrate-side electrode of the electrostatic microphone. Can be reduced.

By arranging the substrate outside the diaphragm of an electrostatic speaker or an electrostatic microphone configured by arranging the substrate side electrode, the diaphragm, and the diaphragm side electrode on both sides of the insulating substrate, The diaphragms and electrodes, which are the components of the electrostatic speaker or the electrostatic microphone, are
In particular, it is possible to protect against the application of a load due to the weather outside the room or the contact with other objects inside the room.

By using a push-pull loudspeaker as the electrostatic loudspeaker in the sound insulation device, the loudspeaker characteristics in a low-frequency range are improved. Furthermore, since the outer surface of this push-pull electrostatic speaker is a substrate with through holes, it is possible to protect the diaphragms and electrodes, which are the components of the speaker, against the application of load due to contact with other objects in the room. it can.

Since the insulating substrate, the substrate-side electrode, the diaphragm, and the diaphragm-side electrode are made of a transparent member, even if the sound insulating device is attached to the window, the window has good lighting and the visibility through the window. Can be widely secured.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a sound insulation device according to Embodiment 1 of the present invention.

FIG. 2 is a partial configuration diagram of the sound insulation device according to Embodiment 1 of the present invention.

FIG. 3 is an overall configuration diagram of a sound insulation device according to Embodiment 2 of the present invention.

FIG. 4 is a partial configuration diagram of a sound insulation device according to Embodiment 3 of the present invention.

FIG. 5 is a partial configuration diagram of a sound insulation device according to Embodiment 4 of the present invention.

FIG. 6 is a partial configuration diagram of a sound insulation device according to Embodiment 5 of the present invention.

FIG. 7 is a partial configuration diagram of a sound insulation device according to Embodiment 6 of the present invention.

FIG. 8 is an overall configuration diagram of a conventional sound insulation device.

[Description of Symbols] 1 electrostatic speaker 2 microphone 3 control unit 8 substrate 9, 9a, 9b substrate-side electrode 10, 10a, 10b diaphragm 11, 11a, 11b diaphragm-side electrode 13 substrate 15 insulating substrate 17 substrate 18 Diaphragm side electrode 19 Substrate with through hole 20 Substrate side electrode

Claims (7)

[Claims] 1. An electrostatic loudspeaker, a microphone attached to a noise source side of the electrostatic loudspeaker, and controlling the electrostatic loudspeaker based on an electric signal from the microphone, thereby controlling the noise source side. And a suppressor for suppressing transmitted sound that is incident on and transmitted through the electrostatic loudspeaker. 2. A substrate, an electrostatic speaker provided on the substrate, and a noise source side of the electrostatic speaker,
By controlling the microphone provided on the substrate and the electrostatic loudspeaker based on an electrical signal from the microphone, transmitted sound that enters the electrostatic loudspeaker from the noise source side and is transmitted is suppressed. A sound insulation device comprising a suppression unit. 3. The electrostatic loudspeaker includes an insulating substrate, a substrate-side electrode provided on one main surface of the insulating substrate, a diaphragm opposed to the substrate-side electrode, and a diaphragm of the diaphragm. A diaphragm side electrode provided on the insulating substrate side, wherein the microphone is disposed on the insulating substrate, a substrate side electrode provided on another main surface of the insulating substrate, and opposed to the substrate side electrode; The sound insulation device according to claim 1, further comprising: a vibrating plate provided; and a vibrating plate-side electrode provided on the insulating substrate side of the vibrating plate. 4. One of the electrostatic speaker or the microphone is an insulating substrate, a substrate-side electrode provided on one main surface of the insulating substrate, a diaphragm disposed opposite to the substrate-side electrode, And a diaphragm-side electrode provided on the insulating substrate side of the diaphragm, wherein the other of the electrostatic speaker or the microphone is the other of the insulating substrate, the substrate-side electrode, and the insulating substrate. 2. The sound insulation device according to claim 1, further comprising: a vibration plate arranged to face the main surface of the vibration plate; and a vibration plate-side electrode provided on the insulating substrate side of the vibration plate. 5. The sound insulation device according to claim 3, wherein the electrostatic speaker or the microphone includes a protection substrate provided outside the diaphragm and protecting the diaphragm. 6. The electrostatic speaker includes a second diaphragm-side electrode provided on a side of the diaphragm opposite to the diaphragm-side electrode, and a plurality of diaphragms arranged opposite to the second diaphragm-side electrode. 4. The sound insulation device according to claim 3, further comprising: a substrate with a through hole having the through hole; and a second substrate-side electrode provided on the diaphragm side of the substrate with the through hole. 5. 7. The insulating substrate, the substrate-side electrode, the diaphragm, and the diaphragm-side electrode constituting the electrostatic speaker and the microphone are formed of a transparent member. 3. The sound insulation device according to 3.