KR20060097839A - Piezoelectric vibrator with double side and piezoelectric a flat panel speaker - Google Patents

Abstract

The present invention relates to a piezoelectric vibrator vibrating on both sides and a piezoelectric flat panel speaker using the same, comprising: first and second flat elastic bodies installed in parallel at regular intervals by a flat elastic stator; A first vibration transmitting elastic body attached to the first flat elastic body corresponding to the second flat elastic body; A second vibration transmitting elastic body attached to the second flat elastic body corresponding to the first flat elastic body; And a double-sided vibrator having an elastic body attached between the first and second vibration transmitting elastic bodies and first and second piezoelectric bodies respectively attached up and down on one side of the elastic body, thereby achieving a large sound pressure. The area of the vibration transmitting elastic body can be reduced to less than half (1/2). As a result, the size of the piezoelectric vibrator can be miniaturized, and the sound pressure and sound quality of the bass portion can be improved.

In addition, the piezoelectric flat panel speaker using the piezoelectric vibrator vibrating on both sides according to the present invention is limited in the diaphragm, so it is possible to manufacture a vibrator of various shapes such as polygons, speakers, and can be made in a form that can be used in underwater or humid environments. .

Piezoelectric vibrator, piezoelectric body, elastic body, plate elastic body, elastic body for vibration transmission

Description

Piezoelectric vibrator vibrating on both sides and piezoelectric flat panel speaker using the same {PIEZOELECTRIC VIBRATOR WITH DOUBLE SIDE AND PIEZOELECTRIC A FLAT PANEL SPEAKER}

1 is a longitudinal sectional view and a bottom view of a piezoelectric vibrator vibrating to a conventional one surface

2A and 2B are longitudinal sectional and bottom views of a piezoelectric vibrator vibrating on both sides according to a first embodiment of the present invention;

3A and 3B are longitudinal sectional and bottom views of a piezoelectric vibrator vibrating on both sides according to a second embodiment of the present invention.

4A and 4B are longitudinal sectional and bottom views of a piezoelectric vibrator vibrating on both sides according to a third embodiment of the present invention.

5A and 5B are longitudinal sectional and bottom views of a piezoelectric vibrator vibrating on both sides according to a fourth embodiment of the present invention.

Figure 6 is a graph comparing the sound pressure (a) by the conventional piezoelectric vibrator structure and the sound pressure (b) by the piezoelectric vibrator structure of the present invention

*** Explanation of symbols for the main parts of the drawing ***

100, 200, 300, 400: double side vibrator

110a: first piezoelectric 110b: second piezoelectric

120a: elastic body for first vibration transmission 120b: elastic body for second vibration transmission

130a: first plate elastic body 130b: second plate elastic body

140: plate elastic body stator 150: elastic body

The present invention relates to a piezoelectric vibrator vibrating on both sides and a piezoelectric flat panel speaker using the same, and more particularly, to a piezoelectric vibrator vibrating on both sides of a vibrating surface having a high sound pressure for the entire sound range and a piezoelectric flat panel speaker using the same.

In general, a piezoelectric vibrator is converted into mechanical vibration by an electrical signal supplied from the outside, and is composed of an elastic body and a piezoelectric body to generate sound by transferring the generated mechanical vibration to the outside. To this end, an electrode for receiving an electrical signal from the outside is attached to the piezoelectric body of the piezoelectric vibrator. Then, a conventional piezoelectric vibrator will be described with reference to the accompanying drawings.

1 is a longitudinal sectional view and a bottom view of a piezoelectric vibrator vibrating to a conventional surface.

As shown in FIG. 1, a conventional piezoelectric vibrator vibrating to one surface is attached to the one surface operating vibrator 10 and the one surface operating vibrator 10 to generate vibration mechanically by an electrical signal supplied from the outside. The vibration transmission elastic body 20 for transmitting the mechanical vibration transmitted from the one-side operating vibrator 10 to the flat elastic body 30, and the vibration transmission elastic body 20 is fixed and transmitted from the vibration transmission elastic body 20. It is configured to include a plate elastic body 30 for transmitting the mechanical vibration to the outside.

A conventional piezoelectric vibrator having such a configuration is that when the one-side operating vibrator 10 is driven by an electrical signal (for example, a digital audio signal) supplied from the outside to generate vibration, one side of the one-side operating vibrator 10 The vibration transmitting elastic body 20 attached to the surface transmits the mechanical vibration generated by the one surface operating vibrator 10 to the flat elastic body 30, thereby generating sound pressure.

However, the conventional piezoelectric vibrator having such a configuration has a problem that the size of the piezoelectric vibrator is increased because the size of the one-side operating vibrator 10 and the vibration transmitting elastic body 20 should be increased as the high sound pressure is generated. In addition, a flattened surface was required for the propagation of uniform vibration.

In addition, in the piezoelectric speaker using a conventional piezoelectric vibrator, there is a problem in generating low sound pressure at a high frequency because the vibration generated from the vibration exciter is formed in the vicinity of the high sound pressure is low and the resonance frequency is 3kHz or more. In order to solve this problem, conventional methods using a plurality of piezoelectric vibrators have been attempted, but have not been successful in obtaining high sound pressure and are not currently widely used.

Meanwhile, the structure of a conventional piezoelectric vibrator for increasing sound pressure may be a bimorph type rectangular actuator type oscillator, such as US Patent 4,593,160, or similarly applied US Patent (US Patent) A method of fabricating an actuator by attaching a ferroelectric wafer to a stressed elastomer such as 5,632,841 has been proposed. In addition, a structure in which a mass body is mounted in order to arrange a plurality of vibrators or to deform the vibration form behind the piezoelectric body has been proposed, but it has not been very effective to increase the sound pressure of the piezoelectric speaker.

Accordingly, the present invention has been made to solve the above problems, and an object of the present invention is to connect the piezoelectric body in a symmetrical structure to a vibration transmitting elastic body up and down to vibrate both sides with the same energy to realize a large sound pressure To provide a vibrating piezoelectric vibrator.

In addition, another object of the present invention is to provide a piezoelectric vibrator that vibrates on both sides to reduce the area of the vibration transmitting elastic body to less than half (by reducing / reducing) and to improve the sound pressure and sound quality of the bass.

Further, another object of the present invention is to provide a piezoelectric vibrator that vibrates on both sides, which simplifies and miniaturizes the structure of the product to simplify the manufacturing process and reduce signal distortion caused by power consumption and noise.

In addition, another object of the present invention is to provide a piezoelectric vibrator that can be made in a variety of forms, such as polygons, less space, design constraints.

In addition, another object of the present invention is to provide a piezoelectric vibrator vibrating on both sides that can be used in underwater or humid environments.

In addition, another object of the present invention to provide a piezoelectric flat panel speaker using a piezoelectric vibrator vibrating on both sides.

Piezoelectric vibrator vibrating on both sides according to the present invention for achieving the above object is a first and second plate elastic body installed in parallel at a predetermined interval by a flat plate elastic stator; A first vibration transmitting elastic body attached to the first flat elastic body corresponding to the second flat elastic body; A second vibration transmitting elastic body attached to the second flat elastic body corresponding to the first flat elastic body; And a double-sided vibrator having an elastic body attached between the first and second vibration transmitting elastic bodies and first and second piezoelectric bodies respectively attached up and down on one side of the elastic body.

Another piezoelectric vibrator vibrating on both sides according to the present invention for achieving the above object is a first plate and a second plate elastic body installed in parallel at regular intervals by a plate elastic stator, and the first plate corresponding to the second plate elastic body A first vibration transmitting elastic body attached to the elastic body; A second vibration transmitting elastic body attached to the second flat elastic body corresponding to the first flat elastic body; And a double-sided vibrator having first and second piezoelectric bodies attached to the first and second vibration transmitting elastic bodies, respectively, and an elastic body attached between the first and second piezoelectric bodies.

Here, the double-sided vibrator further comprises a first and a second piezoelectric body attached to the other side of the elastic body up and down, respectively.

The double-sided vibrator is characterized in that the first and second vibration transmitting elastic bodies are attached to the central portion of the first and second piezoelectric bodies, respectively.

In addition, the double-sided vibrator is characterized in that the elastic body for the first and second vibration transmission is attached to one side of the first and the second piezoelectric body, respectively.

The first and second piezoelectric bodies may be attached to the first and second vibration transmitting elastic bodies and the elastic body by epoxy.

In addition, the external shape supporting the flat elastic body that generates the vibration of the piezoelectric vibrator is characterized in that it is implemented in a polygon.

In addition, the elastic body of the piezoelectric vibrator is characterized in that the metal.

In addition, the elastic body of the piezoelectric vibrator is characterized in that the Young's modulus is a polymer material of 10 GPa or more.

In addition, the piezoelectric material is a PZT (lead zirconium titanate-based material) polycrystalline ceramic material, or PZT (lead zirconium titanate-based material), PMN-PT (lead magnesium niobate-lead titanate-based material), PZN-PT (lead zinc niobate-lead titanate-based material), PYN-PT (lead iterium niobate-lead titanate-based material) and PIN-PT (lead indium niobate-lead titanate-based material It is characterized in that the ferroelectric single crystal material selected from the group consisting of).

In addition, the piezoelectric material may be formed of a single layer or a multilayer structure of the piezoelectric material.

In addition, the piezoelectric body of the multilayer structure may be characterized by stacking layers having the same cross-sectional area and shape, or having a different cross-sectional area or different shapes.

In addition, the piezoelectric material is characterized in that the polycrystalline or single crystal material is made in bulk or thin film form.

A piezoelectric flat panel speaker using a piezoelectric vibrator vibrating on both sides according to the present invention for achieving the above object is provided with the piezoelectric vibrator according to any one of claims 1 to 13.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[First Embodiment]

2A and 2B are longitudinal sectional and bottom views of a piezoelectric vibrator vibrating on both sides according to the first embodiment of the present invention.

As shown in FIGS. 2A and 2B, the piezoelectric vibrator according to the first embodiment includes first and second plate elastic bodies 130a and 130b installed in parallel by a flat elastic stator 140 at regular intervals. The first vibration transmitting elastic body 120a attached to the first plate elastic body 130a corresponding to the second plate elastic body 130b, and the second plate elastic body 130b corresponding to the first plate elastic body 130a. On one side and the other side of the elastic body 150b and the elastic body 150 and the elastic body 150 which are attached between the first and second vibration transmitting elastic body (120a, 120b) attached to the). The double-sided vibrator 100 provided with the 1st and 2nd piezoelectric body 110a, 110b attached up and down, respectively is provided.

As described above, the piezoelectric vibrator is a unimorph (or bimorph) for attaching the first and second piezoelectric material (110a, 110b) up and down respectively on both sides of the elastic body 150 in order to convert an electrical signal into mechanical vibration. As the morph (Bimorph) actuator, the elastic body for transmitting vibration (120a, 120b) for transmitting the mechanical vibration generated by the driving of the first and second piezoelectric (110a, 110b) to the outside It is composed of a simple structure attached to the upper and lower surfaces of 150.

As described above, the double-sided vibrator 100 includes the elastic body 150 and the first and second piezoelectric bodies 110a and 110b attached to one side and the other side of the elastic body 150, respectively, up and down. Electrodes (not shown) for receiving electrical signals (eg, digital audio signals, etc.) from the outside are attached to the first and second piezoelectric elements 110a and 110b.

In the prior art, as described with reference to FIG. 1, the piezoelectric vibrator 10 transmits vibration generated by oscillation only on one surface by an applied electrical signal. That is, the mechanical vibration generated by the piezoelectric vibrator 10 is transferred to the flat plate elastic body 30 by the vibration transmitting elastic body 20 attached to only one side of the piezoelectric vibrator 10 to generate a sound pressure. It was.

However, the piezoelectric vibrator vibrating on both sides according to the present invention attaches the first and second piezoelectric bodies 110a and 110b to one side and the other side of the elastic body 150, respectively, so that both sides of the elastic body 150 are present. By generating vibrations in the upper and lower surfaces, the area of the vibration transmitting elastic body can be reduced to less than half (1/2) in the structure of the piezoelectric vibrator vibrating to one side, and the sound pressure generated can also be increased by 30 dB or more. .

Second Embodiment

3A and 3B are longitudinal sectional and bottom views of a piezoelectric vibrator vibrating on both sides according to a second embodiment of the present invention.

As shown in FIGS. 3A and 3B, the piezoelectric vibrator according to the second embodiment includes first and second plate elastic bodies 230a and 230b installed in parallel by a flat elastic stator 240 at a predetermined interval, and The first vibration transmitting elastic member 220a attached to the first plate elastic body 230a corresponding to the second plate elastic body 230b, and the second plate elastic body 230b corresponding to the first plate elastic body 230a. ) And the second and second piezoelectric elastic members 220b and the first and second piezoelectric bodies 210a and 210b respectively attached to the first and second vibration transmitting elastic bodies 220a and 220b. A double-sided vibrator 200 having an elastic body 250 attached between the first and second piezoelectric bodies 210a and 210b is provided.

In the piezoelectric vibrator according to the second embodiment, the first and second piezoelectric bodies 210a and 210b are attached to upper and lower surfaces of the elastic body 250, respectively, and the first and second piezoelectric bodies 210a and 210b are attached. The first and second vibration transmitting elastic bodies 220a and 220b are respectively attached to the middle portion of the structure.

Like the first embodiment, the piezoelectric vibrator attaches the first and second piezoelectric elements 210a and 210b to the entire upper and lower surfaces of the elastic body 250 to generate vibrations at the upper and lower surfaces of the elastic body 250. In the structure of the conventional piezoelectric vibrator vibrating to one side, the area of the vibration transmitting elastic body can be reduced to less than half (1/2), and the sound pressure generated can also be increased by 30 dB or more.

Third Embodiment

4A and 4B are longitudinal sectional and bottom views of a piezoelectric vibrator vibrating on both sides according to a third embodiment of the present invention.

The piezoelectric vibrator according to the third embodiment of the first and second piezoelectric bodies 310a and 310b of the double-sided vibrator 300 having the structure as shown in FIG. It shows a structure attached to 320a) (320b). Here, as shown in FIGS. 4A and 4B, the double-sided vibrator 300 may include first and second piezoelectric bodies having the first and second vibration transmitting elastic bodies 220a and 220b attached to one side thereof, respectively. 310a) and 310b and an elastic member 350 attached between the first and second piezoelectric bodies 310a and 310b. Here, the operation and effects of the piezoelectric vibrator according to the third embodiment are the same as those of the first and second embodiments.

[Example 4]

5A and 5B are longitudinal sectional and bottom views of a piezoelectric vibrator vibrating on both sides according to a fourth embodiment of the present invention.

The piezoelectric vibrator according to the fourth embodiment has the same cross-sectional structure as the second embodiment shown in FIG. 3, but includes first and second flat elastic bodies 430a and 430b that generate vibrations of the double-sided vibrator 400. It shows that the appearance form to support the circular implementation.

Meanwhile, in the present invention, the appearance of the piezoelectric vibrator may be implemented as a polygon rather than a circle.

Fig. 6 is a graph showing a comparison between the sound pressure (a) of the conventional piezoelectric vibrator structure and the sound pressure (b) of the piezoelectric vibrator structure of the present invention. As shown in the graph, it is possible to improve the sound pressure by 30 dB or more with an area smaller than half (1/2) smaller than the conventional vibration transmitting elastic body area.

In the piezoelectric vibrator vibrating on both sides according to the present invention shown in Figures 2 to 5, the elastic bodies (150 to 450) is preferably a metal, such as steel, aluminum alloy. In addition, a polymer material having a high Young's modulus, preferably having a Young's modulus of 10 Gpa or more is possible, and the type thereof is not particularly limited.

As a means for attaching the first and second piezoelectric bodies 110a and 110b and the elastic body 150, an adhesive having a high hardness value after curing, such as epoxy, is preferable, thereby minimizing signal attenuation. Can be.

In addition, the thicknesses of the first and second piezoelectric bodies 110a and 110b and the elastic body 150, the shape and the size of the polyhedron, and the center of gravity may be appropriately adjusted according to the applied device.

In addition, the piezoelectric material of the piezoelectric body 110a is preferably a polycrystalline ceramic of PZT (lead zirconium titanate-based material) widely used in the related art, or a piezoelectric single crystal ceramic material having excellent piezoelectric properties.

In addition, the ferroelectric single crystal materials used in the present invention include PMN-PT (lead magnesium niobate-lead titanate-based material), PZN-PT (lead zinc niobate-lead titanate-based material), PZT (lead zirconium Titanate-based material), PYN-PT (lead iterium niobate-lead titanate-based material), PIN-PT (lead indium niaobate-lead titanate-based material).

The piezoelectric properties of PMN-PT single crystal and PZT ceramic and PVDF among the single crystal materials according to the present invention were compared in Table 1 below.

 Properties  PVDF  PZT-5A  PZT-5H  PMN-PT Monocrystalline Density (kg / m ³ ) 1780 7750 7500 8000 Dielectric constant 12 1600 3400 > 5000 Dielectric loss (%) - 2 2 <0.5 Electromechanical Coupling Factor (k ₃₃ ) (%) 11 70.5 75 93 Piezoelectric Strain Factor (d ₃₃ ) (pC / N) 30 374 593 > 2200 Piezoelectric Voltage Coefficient (g ₃₃ ) (10 ^-3 Vm / N) 2 24.8 19.7 44

Table 1 was measured by the IEEE standard resonant measurement (measured value). The amount of deformation due to voltage was measured using an interferometric measurement. d33, the piezoelectric strain coefficient of the thickness mode, k33 is the electromechanical coupling coefficient in the thickness mode, and g33 is the piezoelectric voltage coefficient in the thickness mode.

The amount of deformation generated when an electric field is applied to a material having piezoelectric properties can be expressed by Equation 1 below.

here,

ΔL = strain [m]

S = strain

Lo = length before deformation [m]

dij = piezoelectric strain factor [pV / m]

E = field strength [V / m]

to be.

It can be seen from Equation 1 that the displacement of the piezoelectric material is proportional to the piezoelectric strain coefficient dij.

According to Table 1, PMN-PT single crystal is used as the piezoelectric material than PVDF or PZT ceramic series. 4 or 70 times more excellent properties. Therefore, in the present invention, it is preferable to use PMN-PT piezoelectric single crystal as a characteristic value or to use a laminated form of PZT ceramics.

According to another feature of the present invention, the single crystal materials of the first and second piezoelectric materials 110a and 110b may have a bulk or film structure and may have a single layer or a stacked structure. When the piezoelectric single crystal material is formed in a film form, the piezoelectric single crystal material in bulk may be polished in a thin film form and then attached to an electrode or may be polished in a thin film form after being attached to an electrode. When the piezoelectric single crystal material is formed in a thin film form, the overall thicknesses of the first and second piezoelectric materials 110a and 110b may be reduced.

The present invention is not limited to the above-described embodiments, but can be variously modified and changed by those skilled in the art, which should be regarded as included in the spirit and scope of the present invention as defined in the appended claims. something to do.

As described above, according to the piezoelectric vibrator vibrating on both sides according to the present invention and the piezoelectric flat panel speaker using the same, the piezoelectric body is connected to the upper and lower symmetrical structure to the vibration transmitting elastic body to vibrate both sides with the same energy to generate sound pressure. Larger implementations (eg 30 dB or more) can be achieved.

In addition, by reducing the area of the vibration transmitting elastic body to less than half (1/2) to enable the miniaturization and improve the sound pressure and sound quality of the bass.

In addition, since the piezoelectric vibrator vibrating on both sides according to the present invention has a simple structure, the manufacturing process can be significantly simplified, and the energy efficiency can be greatly improved compared to the power consumption, thereby reducing power consumption, miniaturization of the product, and noise. Reduction of signal distortion can be realized.

In addition, the piezoelectric flat panel speaker using the piezoelectric vibrator according to the present invention can make a variety of products, such as polygons can be widened the field of application by receiving less space, design constraints.

In addition, the piezoelectric flat panel speaker using the piezoelectric vibrator vibrating on both sides according to the present invention can be made in a form that can be used underwater or in a humid environment because of the limited limitation of the diaphragm.

Claims (14)

First and second plate elastic bodies installed in parallel at regular intervals by the plate elastic body stator; A first vibration transmitting elastic body attached to the first flat elastic body corresponding to the second flat elastic body; A second vibration transmitting elastic body attached to the second flat elastic body corresponding to the first flat elastic body; And A double-sided vibrator having an elastic body attached between the first and second vibration transmitting elastic bodies and first and second piezoelectric bodies attached to one side of the elastic body, respectively, up and down. Oscillator. First and second plate elastic bodies installed in parallel at regular intervals by a plate elastic body stator, and a first vibration transmitting elastic body attached to the first plate elastic body corresponding to the second plate elastic body; A second vibration transmitting elastic body attached to the second flat elastic body corresponding to the first flat elastic body; And And a double-sided vibrator having first and second piezoelectric bodies attached to the first and second vibration transmitting elastic bodies, respectively, and an elastic body attached between the first and second piezoelectric bodies. Piezoelectric vibrator. The method of claim 1, wherein the double-sided vibrator is: Piezoelectric vibrator vibrating on both sides characterized in that it further comprises a first and a second piezoelectric body respectively attached to the other side of the elastic body up and down. The method of claim 2, wherein the double-sided vibrator is: And a piezoelectric vibrator on both sides of the first and second piezoelectric bodies, wherein the elastic bodies for the first and second vibration transmissions are respectively attached. The method of claim 2, wherein the double-sided vibrator is: The piezoelectric vibrator vibrating to both sides, characterized in that the first and second vibration transmission elastic body is attached to one side of the first and second piezoelectric body, respectively. The method according to claim 1 or 2, The first and second piezoelectric vibrators are piezoelectric vibrators on both sides characterized in that attached to the elastic body for the first and second vibration transmission and the elastic body by epoxy. The method according to claim 1 or 2, The piezoelectric vibrator vibrating on both sides characterized in that the external shape to support the flat elastic body for generating the vibration of the piezoelectric vibrator is implemented in a polygon. The method according to claim 1 or 2, The piezoelectric vibrator vibrating on both sides of the elastic body of the piezoelectric vibrator is a metal. The method according to claim 1 or 2, The elastic body of the piezoelectric vibrator is a piezoelectric vibrator vibrating on both sides, characterized in that the Young's modulus is a polymer material of 10GPa or more. The method according to claim 1 or 2, The piezoelectric material is a PZT (lead zirconium titanate-based material) polycrystalline ceramic material as a piezoelectric material, or PMN-PT (lead magnesium niobate-lead titanate-based material), PZN-PT (lead zinc niobate-lead titanium) Nate-based materials), PZT (lead zirconium titanate-based materials), PYN-PT (lead iterium niobate-lead titanate-based materials) and PIN-PT (lead indium niobate-lead titanate-based materials) A piezoelectric vibrator vibrating on both sides characterized in that the ferroelectric single crystal material selected from the group consisting of. The method of claim 10, The piezoelectric material vibrates on both sides of the piezoelectric material, characterized in that the piezoelectric material is composed of a single layer or a multilayer structure. The method of claim 11, The piezoelectric vibrator of the multilayer structure may vibrate two-sided piezoelectric vibrators, characterized in that the layers having the same cross-sectional area and shape may be laminated or may have different cross-sectional areas or different shapes. The method of claim 10, The piezoelectric material is a piezoelectric vibrator vibrating on both sides, characterized in that the polycrystalline or single crystal material is made in bulk or thin film form. The piezoelectric flat panel speaker provided with the piezoelectric vibrator of any one of Claims 1-13.

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