JPH11305782A - Sound absorbing and damping device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the sound absorbing and damping device which can not only merely damp vibration energy, but also convent it into electric energy. SOLUTION: This device is composed principally of a piezoelectric thin film 1 which is polarized along the thickness, a resistance layer 3 which is stacked on at least one surface side of the piezoelectric film 1 and can convent a voltage developed by the vibration of the piezoelectric thin film 1 into a current and output it, and a current collecting layer 2 which is stacked on the surface of the piezoelectric thin film 1 where the resistance layer 3 is not stacked when the resistance layer 3 is stacked only on one side of the piezoelectric thin film 1. Here, the electric energy generated by converting the vibration energy is outputted by the resistance layer 3 which functions as an external resistance. Namely, the resistance layer 3 continuously performs the energy conversion. Then the current collecting layer 2 collects electric charges accumulated in the piezoelectric thin film 1 and outputs them as a current.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound absorbing / damping device, and more particularly to a sound absorbing / damping device using a piezoelectric thin film.

[0002]

2. Description of the Related Art Both sound absorbing and damping means consist of attenuating vibration energy, and specific examples of sound absorbing (soundproofing) means are used for windows of buildings such as houses and buildings. There is a pair of glass, and as specific examples of the vibration damping means, various vibration damping steel plates and vibration damping alloys are known.

In a sound absorbing and damping device, it is desirable from the viewpoint of effective use of energy if the vibration energy can be converted not only to attenuated but also to other available energy.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a sound absorbing and damping device which can not only attenuate vibration energy but also convert it to electric energy. It is in.

[0005]

Means for Solving the Problems As a result of intensive studies, the present inventor focused on a piezoelectric material known as a material that can be converted into vibrational energy and electric energy, and as a result, as a result, With the adoption of the structure, it was found that there was no need for an external resistor to convert the voltage generated by the vibration of the piezoelectric thin film into a current and output it, and it could be used as a sound absorbing and vibration damping device. The present invention has been completed.

That is, the gist of the present invention is that a piezoelectric thin film (1) polarized in the thickness direction is laminated on at least one side of the piezoelectric thin film (1), and a voltage generated by vibration of the piezoelectric thin film (1) is converted into a current. And a resistance layer (3) of the piezoelectric thin film (1) when the resistance layer (3) is stacked only on one side of the piezoelectric thin film (1). A sound absorbing and damping device characterized by being mainly composed of a current collecting layer (2) laminated on a non-exposed surface.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. 1 is an explanatory side view of an example of the sound absorbing and damping device of the present invention, FIG. 2 is a partially sectional explanatory view showing a state where the sound absorbing and damping device shown in FIG. 1 is set on a window frame, and FIG. ,
FIG. 4 is an explanatory diagram of an equivalent circuit of the sound absorbing / damping device shown in FIG. 1 formed in the state shown in FIG. 2, and FIG.
Plane explanatory view of an example of a resistance layer used in the vibration damping device, FIG.
FIG. 6 is an explanatory diagram of an equivalent circuit formed by the sound absorbing / damping device provided with the resistance layer shown in FIG. 4, and FIGS. 6 (a) to 6 (d) show an example of manufacturing a preferred sound absorbing / damping device of the present invention. 7 is an explanatory diagram of an equivalent circuit of the sound absorbing / damping device shown in FIG. 6, and FIGS. 8 (a) and 8 (b) show preferred sound absorbing / damping devices of the present invention in which a heat ray blocking film is laminated. It is explanatory drawing which shows the manufacturing process of an example of a vibration damping device.

[0008] As the piezoelectric thin film (1), for example, a piezoelectric ceramics molded article, a 0-
3 type composite piezoelectric body, 2-2 type or 1-3 type composite type piezoelectric body having piezoelectric columns arranged in a resin matrix, vinylidene cyanide, PVDF, PVDF-T
A piezoelectric polymer such as rFe may be used. Piezoelectric thin film (1)
For the polarization treatment in the thickness direction, a voltage treatment method described below using the current collecting layer (2) as a polarization electrode is simple and preferable, but it can also be performed by corona discharge treatment. In this case, the lamination of the current collecting layer (2) for the purpose of polarization is unnecessary.

When the above-mentioned voltage processing method is performed, the current collecting layer (2) is laminated on both surfaces of the piezoelectric thin film (1) and has a function of polarizing the piezoelectric thin film (1) in its thickness direction. Normal,
The current collecting layer (2) is formed of a metal thin film. On the other hand, the resistance layer (3) has a function of converting a voltage generated by the vibration of the piezoelectric thin film (1) into a current and outputting the current (function as an external resistance). Therefore, the resistance layer (3) is formed of a material having an appropriate resistance value.

A sound absorbing / vibration damping device (10) of the present invention shown in FIG. 1 which employs the above-described voltage processing method has a piezoelectric thin film (1) as described above, and a piezoelectric thin film (1) laminated on both sides of the piezoelectric thin film (1). And a resistance layer (3) laminated on both surfaces of the current collecting layer (2) and capable of converting a voltage generated by the vibration of the piezoelectric thin film (1) into a current and outputting the current. Consists of

The sound absorbing / vibration damping device having the above-described structure is, for example,
After a high voltage is applied between the current collecting layers (2) to polarize the piezoelectric thin film (1) in its thickness direction, the piezoelectric thin film (1) can be used as a component of a sound absorbing / damping device. The above-mentioned polarization treatment is performed, for example, by applying a voltage of 2 to 5 Kv / mm for about 5 to 30 minutes in the case of a piezoelectric ceramic, and 20 to 30 in the case of a polymer-based piezoelectric material.
This is performed by applying a voltage of 70 Kv / mm for about 20 to 90 minutes.

The electric energy converted from the vibration energy is output by a resistance layer (3) having a function as an external resistance. That is, energy conversion is continuously performed by the resistance layer (3). In addition, in the sound absorbing / damping device illustrated in FIG. 1, a resistance layer (3) is laminated on each current collecting layer (2). It is sufficient that the piezoelectric thin film (1) is laminated on at least one side. A current collecting layer (2) is laminated on the surface of the piezoelectric thin film (1) on which the resistance layer (3) is not laminated, and the electric charge accumulated in the piezoelectric thin film (1) by the current collecting layer (2). Are collected and output as a current.

Reference numeral (4) denotes a laminate (resistance layer (3) / current collecting layer (2) / piezoelectric thin film (1) / current collecting layer (2) / resistance layer ( 3) represents an insulating member disposed on the four end faces. The insulating member (4) has a function of ensuring electrical insulation at the end of the laminate, and is constituted by means such as coating with an insulating paint or laminating an insulating film.

The performance of the sound absorbing / damping device (10) of the present invention has frequency dependency, and is specifically expressed by the following known formula. In the formula, ω represents a vibration frequency, C represents electric capacity, and R represents resistance.

[0015]

Ω = 1 / (CR)

That is, the vibration frequency (ω) to be attenuated depends on the electric capacity (C) of the piezoelectric thin film (1) and the resistance value (R) of the resistance layer (3). The dielectric constant of the piezoelectric thin film (1) is controlled by the selection, thickness and the like of the piezoelectric body. The resistance value (R) (conductivity) of the resistance layer (3) is controlled by selection of a constituent material, thickness, and the like.

In the sound absorbing / damping device (10) according to a preferred embodiment of the present invention, the piezoelectric thin film (1) is a transparent piezoelectric body, and the current collecting layer (2) and the resistance layer (3) are transparent layers. Since the sound absorbing / damping device of this aspect is transparent,
It is suitable as a sound absorbing device applied to a window, and has an advantage that the inside can be observed when a box-shaped sound absorbing / damping device surrounding noise generating equipment such as a motor is used.

In another preferred embodiment of the sound absorbing / damping device (10) of the present invention, the current collecting layer (2) is a transparent layer formed by a physical film forming method, and the resistance layer (3) is formed by a physical layer. It is a transparent layer formed of a transparent conductive paint.

The physical film formation method described above refers to a method capable of forming a thin film of a single material, such as a vapor deposition method or a sputtering method. The conductive material forming the current collecting layer (2) includes gold, silver, copper, palladium, indium-tin, zinc,
Examples include aluminum, zinc oxide, aluminum oxide, indium-tin oxide (ITO), and indium-antimony oxide (IAO). In particular, from the viewpoint of cost and transparency, ITO and IAO are preferably used. .
On the other hand, examples of the formation method using the transparent conductive paint include spin coating, spray coating, and a coating method such as roll coating, screen printing, and the like. Can be prepared by dispersing the fine particles of the conductive material.

The sound absorbing and damping device of the above embodiment has the following advantages. That is, according to a physical film forming method such as a sputtering method, a suitable current collecting layer (2) having an extremely low resistance value can be easily formed. On the other hand, according to the formation method using the transparent conductive paint, a suitable resistance layer (3) having a relatively high resistance value can be easily formed. That is, the resistance layer (3) having usually 1 to 50 KΩ, preferably 5 to 30 KΩ, and more preferably about 10 KΩ can be easily formed.

The sound absorbing / damping device (10) of the present invention is applied to a window, for example, and is used exclusively as a sound absorbing device.
As shown in FIG. 2, it is integrated with the glass (20) and fixed by a metal window frame (30) made of Al or the like. in this case,
The metal window frame (30) is formed of the above-mentioned laminate (the resistance layer (3) /
It has a function as a fixing member for fixing the current collecting layer (2) / piezoelectric thin film (1) / current collecting layer (2) / resistance layer (3)).

The reference numeral (40) in FIG.
The connection member (40) is a connection member for electrically connecting the resistance layer (3) on the lower surface side of the vibration damping device (10) to the metal window frame (30). Foil (Al
Foil). In addition, the sound absorbing / vibration suppression device (1)
The resistance layer (3) on the upper surface side of the metal window frame (3)
0) and is conducted. The equivalent circuit formed in this case is as shown in FIG.

The reason is that a film thickness of 30 cm × 40 cm 4
A current collecting layer (2) made of ITO is formed on both sides of a 0 micron PVDF film by a sputtering method, then subjected to a polarization treatment, and a 10 KΩ film is formed on both sides of the current collecting layer (2) by a printing method of an ITO-containing transparent layer paint. After forming the resistance layer (3), an insulating member (4) is formed to produce a sound absorbing / vibration suppressing device (10).
In the manner described above, a test chamber (closed space in which a noise level meter is arranged) is set on a metal (Al) window frame (30), and noise (100 to 2000 Hz) is radiated from outside, and the internal sound level is measured. As a result, a decrease in sound pressure of about 9 db was confirmed as compared with the case where only the glass surface was used (sound absorption test I).

In another preferred embodiment of the sound absorbing / vibration suppressing device of the present invention, the resistance layer (3) has a resistivity distribution.
Specifically, as shown in FIG. 4, a plurality of resistance layers (3a), (3b), formed of materials having different conductivity (resistance value),
(3c) forms one resistance layer (3), and the resistance layer (3)
Have a distribution of conductivity (resistance value) in the plane of.

According to the sound absorbing / damping device of the above embodiment, a distribution is generated in the frequency capable of sound absorbing / damping according to the above equation,
Broadband sound absorption and vibration suppression can be achieved. The equivalent circuit formed in this case is as shown in FIG. The above-described resistance layer (3) can be easily formed by a printing method using conductive paints having different conductivity (resistance value).

The resistance layer (3) is (3a): 2.5K
Ω, (3b): 1.5 KΩ, (3c): 2.5 KΩ, except that the sound absorption / vibration control device manufactured in the same manner as that used in the sound absorption test I described above was subjected to the sound absorption test described above. As a result of performing the same evaluation as I, a sound pressure drop of about 10 db was confirmed, and the 3 db attenuation frequency range was expanded to about twice that of the sound absorbing / vibration suppression device used in the above-described sound absorbing test I. (Sound absorption test II).

According to another preferred embodiment of the present invention, there is provided a piezoelectric thin film (1) having a current collecting layer (2) laminated on both sides.
, And the piezoelectric thin films are stacked with the polarization direction aligned for each layer, and the piezoelectric thin films are electrically connected in parallel every other layer. The sound absorbing / damping device having such a structure is manufactured by, for example, the following method.

First, as shown in FIG. 6A, a plurality of piezoelectric thin films (1) having current collecting layers (2) laminated on both surfaces are prepared. In the illustrated example, the number is three, but may be four or more, and the number may be an odd number or an even number.
The current collecting layer (2) is formed on the upper and lower surfaces of the piezoelectric thin film (1) except for one end of each. The reason for this is to prevent an electrical short circuit with the adjacent current collecting layer (2) in the next laminating step so that an independent parallel circuit is formed. In FIG. 6A, an arrow attached to the left side of each piezoelectric thin film (1) indicates the polarization direction of each piezoelectric thin film (1).

Next, as shown in FIG. 6B, three piezoelectric thin films (1) are laminated, and connection portions (2a) are provided on both end surfaces.
To form a parallel circuit. The connection part (2a) does not need to be formed by a sputtering method, and does not need to be transparent, and can be formed using an appropriate conductive paint or paste.

Next, as shown in FIG. 6 (c), after forming a resistance layer (3) on both sides of the above-mentioned laminate according to the above-mentioned method, as shown in FIG. 6 (d), The insulating member (4) is formed according to the method.

According to the sound absorbing and damping device of the above embodiment, the effective area is increased by the laminated structure.
Although the in-plane area is the same, the sound absorption / damping performance is improved. The equivalent circuit in this case is as shown in FIG.

It should be noted that both sides of the IT
The sound absorption / vibration suppression device manufactured in the same manner as that used in the sound absorption test I described above, except that three PVDF films on which the current collecting layer (2) made of O was formed were used.
As a result, the sound pressure was reduced by about 17 db (sound absorption test III).

A sound absorbing / damping device according to another preferred embodiment of the present invention includes a plurality of piezoelectric thin films (1) having different thicknesses. According to the sound absorbing and damping device of this aspect, by providing a plurality of Cs having different values as C in the above-described formula, various types of C and S can be used, similarly to the sound absorbing and damping device used in the sound absorbing test II. Effectively acts on vibrations of various frequencies.

In the sound absorbing and damping device according to the present invention, the sound absorbing and damping device, which is entirely transparent, is installed on a window of a building such as a house, a building, an automobile, a railway aircraft, a ship, or the like. It is possible to absorb sound and control vibration in the vicinity of a seamless space while taking light.

The current collecting layer (2) is made of indium-tin oxide (ITO) or indium-antimony oxide (IA).
O), and the resistance layer (3) is formed of a transparent conductive paint containing ITO or IAO. The sound absorbing / vibration suppression device of the present invention also has a heat ray blocking function. Therefore, when applied to a window, the effect of promoting the cooling effect by the heat ray absorbing action of ITO or IAO and saving the cost of cooling can be obtained.

The sound absorbing / vibration control device of the present invention having the above-mentioned heat ray blocking function is provided on the surface of a transparent film such as a polyester film or the like by a thin film of ITO or IAO or an IT film.
A heat ray blocking film formed by forming a thin film of a transparent conductive paint containing O or IAO may be laminated. More specifically, as shown in FIG. 8A, a dedicated heat ray blocking film (50) in which, for example, an ITO thin film (5) is laminated on the surface of a transparent film (6) and the above-described sound absorbing / vibration suppressing device of the present invention. An apparatus (10) is prepared, and both are laminated as shown in FIG. 8 (b).

The sound absorbing / damping device of the present invention can also be connected to a condenser, thereby making up a power generating device. In particular, the window of a vehicle is an area that is easily affected by vibration and wind and easily generates electric power.Therefore, when the sound absorbing and damping device of the present invention is applied to an automobile, it can be used for charging a battery, and can be used for railways and the like. It can be used to replenish the power source of aircraft and has energy saving effect. The entire condenser can be made transparent, similarly to the sound absorbing / damping device of the present invention.

That is, the sound absorbing / damping device of the present invention has not only the sound absorbing / damping function, but also the function of generating electricity and cutting off the heat rays. Further, for example, until the sound pressure exceeds a certain threshold value. Can be a switching system in which the power generation system operates and the sound absorbing / damping system operates above the threshold value.

In the sound absorbing and damping device of the present invention, the overall thickness is usually 1 to 10 mm, the thickness of the piezoelectric thin film (1) is usually 10 to 500 μm, and the thickness of the current collecting layer (2) and the resistance layer (3) is The thickness is usually set to 10 to 500 μm. On the other hand, the overall size (area) is usually 10 to 200 cm long and 10 cm wide.
３００300 cm.

[0040]

According to the present invention described above, a sound absorbing and damping device capable of converting vibration energy into electric energy as well as simply attenuating the vibration energy is provided, and the industrial value of the present invention is remarkable.

[Brief description of the drawings]

FIG. 1 is an explanatory side view of an example of a sound absorbing / damping device of the present invention.

FIG. 2 is a partial cross-sectional explanatory view showing a state where the sound absorbing / damping device shown in FIG. 1 is set on a window frame.

FIG. 3 is a diagram illustrating the sound absorbing / forming device shown in FIG. 1 formed in the state shown in FIG.
Explanatory drawing of the equivalent circuit of the vibration damping device

FIG. 4 is an explanatory plan view of an example of a resistance layer used in a preferable sound absorbing / damping device of the present invention.

FIG. 5 is an explanatory diagram of an equivalent circuit formed by the sound absorbing / damping device including the resistance layer shown in FIG.

FIG. 6 is an explanatory view showing a manufacturing process of an example of a preferable sound absorbing / damping device of the present invention.

FIG. 7 is an explanatory diagram of an equivalent circuit of the sound absorbing and damping device shown in FIG.

FIG. 8 is an explanatory view showing a manufacturing process of an example of a preferred sound absorbing / damping device of the present invention in which a heat ray shielding film is laminated.

[Explanation of symbols]

 1: Piezoelectric thin film 2: Current collecting layer 3: Resistive layer 4: Insulating member 5: ITO thin film 6: Transparent film 10: Sound absorbing and damping device 20: Glass 30: Metal window frame 40: Connecting member 50: Heat ray blocking film

Claims (9)

[Claims] 1. A piezoelectric thin film (1) polarized in a thickness direction.
A resistance layer (3) laminated on at least one side of the piezoelectric thin film (1) and capable of converting a voltage generated by the vibration of the piezoelectric thin film (1) into a current and outputting the current, and only on one side of the piezoelectric thin film (1) When the resistance layer (3) is laminated, the piezoelectric thin film (1) is mainly composed of a current collecting layer (2) laminated on a surface of the piezoelectric thin film (1) where the resistance layer (3) is not laminated. Sound absorption and vibration control device. 2. The sound absorbing device according to claim 1, comprising a layer structure of a resistance layer (3) / a current collecting layer (2) / a piezoelectric thin film (1) / a current collecting layer (2) / a resistance layer (3).・ Damping device. 3. The sound absorbing and damping device according to claim 1, wherein the piezoelectric thin film (1) is a transparent piezoelectric material, and the current collecting layer (2) and the resistance layer (3) are transparent layers. 4. The current collecting layer (2) is a transparent layer formed by a physical film forming method, and the resistance layer (3) is a transparent layer formed by a transparent conductive paint. The sound absorbing / damping device according to any one of the above. 5. The sound absorbing / damping device according to claim 1, wherein the resistance layer has a resistivity distribution. 6. A plurality of piezoelectric thin films (1) each having a current collecting layer (2) laminated on both surfaces thereof, and the piezoelectric thin films are laminated with their polarization directions aligned for each layer. The sound absorbing / damping device according to any one of claims 1 to 5, wherein the piezoelectric thin films are electrically connected in parallel every other layer. 7. The sound absorbing / damping device according to claim 6, comprising a plurality of piezoelectric thin films (1) having different thicknesses. 8. The current collecting layer (2) is made of indium-tin oxide (ITO) or indium-antimony oxide (IA).
O), wherein the resistance layer (3) is formed of a transparent conductive paint containing ITO or IAO, and has a function of blocking heat rays as well. apparatus. 9. A heat-shielding film formed by forming a thin film of indium-tin oxide (ITO) or indium-antimony oxide (IAO) or a thin film of ITO or a transparent conductive paint containing IAO on the surface of a transparent film. A heat ray blocking function which is formed by stacking
8. The sound absorbing / damping device according to any one of 8 above.