KR100959763B1 - Piezoelectric speaker - Google Patents

Abstract

PURPOSE: A piezoelectric speaker is provided to obtain an acoustic property similar to a voice coil type speaker or conventional magnetic circuit by efficiently improving a low pitched tone area. CONSTITUTION: A first vibration plate(20) is attached to the center of an acoustic conversion piezoelectric device. A supporter passes through the center of the voice conversion piezoelectricity and is fixed. A support frame supports the supporter. A second vibration plate(50) is contacted with the first vibration plate and is extended to the outer direction. A support frame includes an edge frame.

Description

Piezoelectric speaker

The present invention relates to a piezoelectric speaker.

Republic of Korea Patent Publication No. 1985-0005216

Korean Laid-Open Patent No. 2001-0030510

Republic of Korea Patent No. 0729152

Journal of the Acoustical Society of Korea, Vol. 2, No. 2 (1992), Jinsoo Kim and four others pp28-36 "A Study on the Acoustic Characteristics of Acoustic Transducer Composed of PZT / Metal"

Proceedings of the Acoustical Society of Korea Conference, Vol. 18, No. 1 (s) (1999), Young-Joon Ko and 2 others pp307-310 "A Vibration Analysis of Metal-Piezoelectric Ceramic Composite Plates"

Piezoceramic's processing technology and manufacturing process have improved the application of piezoceramic to a wide range of applications. In particular, piezoelectric ceramics can be applied as an acoustic transducer, and various studies have been conducted.

Korean Unexamined Patent Publication No. 1985-0005216, which is an example of such various studies, discloses a piezoelectric speaker using piezoelectric ceramics.

The above example applied as a piezoelectric speaker is a structure for transmitting the vibration of the piezoelectric ceramic to the diaphragm by installing a transfer body between the piezoelectric ceramic (piezoelectric transducer) and the diaphragm for generating air movement.

The structure above is contrary to the recent trend of miniaturization and thinning, and simply shows the possibility as an acoustic transducer using piezoelectric ceramics.

As another well-known example, the Journal of the Acoustical Society of Korea, Vol. 2 No. 2 (1992), Kim Jin-soo et al. Pp. 28-36 "Study on the Acoustic Characteristics of Acoustic Transducers Composed of PZT / Metal" 18 (1) (1999), Young-Joon Ko and 2 others pp307-310 "Vibration analysis of metal-piezoceramic composite plates", etc., attached piezoceramic to metal diaphragm to form vibrator structure to analyze acoustic characteristics have.

These papers show that piezoceramic speakers can be made smaller and thinner and have better sound quality than simple buzzers and pronunciations as a concrete attempt for high quality acoustic conversion of piezoelectric ceramics.

As another known example, Republic of Korea Patent Publication No. 2001-0030510 and Republic of Korea Patent No. 0729152 apply the metal-piezoceramic technology disclosed in the above-mentioned papers, in particular, Republic of Korea Patent Publication No. 2001-0030510 In order to mount a speaker such as a buzzer, the structure of the piezoelectric speaker is modified, and Korean Patent No. 0729152 discloses a complicated structure for effective vibration transmission of the piezoelectric speaker.

However, the above-described conventional techniques have a simple structure, but have low and low mid-range characteristics, and play a single frequency or narrow frequency bands (toys, buzzers, melody cards) or speakers for reproducing high frequency sounds due to the biased play band characteristics. Applied, there was a problem that does not apply to the sound equipment corresponding to the mid-low range characteristics.

The present invention has been made to solve the above-described problems, the object of the present invention is made of a relatively simple structure, due to this, the speaker is compact, thin, various flat panel display, a car interior speaker, etc. It can be applied to the application, and in particular, it effectively improves the bass region characteristics, thereby providing a piezoelectric speaker showing acoustic characteristics similar to those of a conventional magnetic circuit or voice coil type speaker.

The present invention for achieving the above object

Acoustic transducer piezoelectric,

A first vibration plate attached to the center of the acoustic transducer,

A supporter fixed through the center of the acoustic transducer;

It includes a support frame for supporting the supporter,

The support frame further comprises an outer frame,

It is characterized in that it further comprises a second vibration plate which is bonded to the first vibration plate and extended in the outward direction and bonded to the outer frame.

In addition, the acoustic conversion piezoelectric body and the first vibration plate according to the present invention is characterized in that the center is eccentrically attached.

In addition, the second vibration plate applied to the present invention is characterized in that it further comprises that the dust cap is bonded.

In addition, the second vibration plate applied to the present invention is characterized in that the outer peripheral surface is made of a convex or concave shape is finished.

In addition, the second vibration plate applied to the present invention is characterized in that the outer peripheral surface is made of a flat surface.

In addition, the second vibration plate applied to the present invention further comprises an edge formed with an outer circumferential surface adhered to the outer circumferential surface of the second vibration plate and extended in the outward direction and then finished in any one of concave, convex, and multi-pleat corrugated shapes. It features.

In addition, the outer circumferential surface of any one of the concave, convex, multi-stage corrugated shape of the edge applied to the present invention is characterized in that the concave, convex, multi-stage corrugated shape is formed and finished to form a flat adhesive surface.

In addition, the outer circumferential surface of the edge applied to the present invention is characterized in that it is finished in a flat shape.

In addition, the outer frame applied to the present invention is characterized in that it is bonded with any one of the adhesive surface of the concave, convex, multi-stage corrugated shape of the edge.

In addition, the outer frame applied to the present invention is characterized in that it further comprises that the flat outer peripheral surface of the edge is bonded.

Further objects and effects of the present invention will become apparent from the following detailed description, and the detailed description and examples showing the preferred embodiments of the present invention do not limit the scope of the present invention.

The piezoelectric speaker according to the present invention has the following frequency characteristics when compared with a general voice coil speaker.

As mentioned above, the mid- and low-frequency characteristics below 1,000KHz, especially below 500 Hz, have been remarkably improved to secure characteristics similar to those of conventional magnetic circuits or voice coil speakers not found in conventional piezoelectric speakers.

Hereinafter, one preferred embodiment according to the present invention will be described in detail with reference to the accompanying drawings. First, like reference numerals designate functionally identical or similar parts throughout the drawings.

1 is a perspective view of a first embodiment of a piezoelectric speaker according to the present invention, Figure 2 is an exploded perspective view of Figure 1, Figure 3 is a partial cross-sectional view of FIG.

First, the shape of the piezoelectric speaker applied according to the first embodiment of the present invention, through the piezoelectric speaker through Figure 1 can determine the overall shape, as shown in Figure 2 the utilization of the piezoelectric speaker is a flat display, automotive In order to suit the purpose of a built-in speaker or the like, for example, it has a product thickness or a lightweight structure of 15 mm or less.

Still, the present invention is not limited to the use of the illustrated model.

Piezoelectric speaker according to the first embodiment of the present invention for the above purpose, as shown in the exploded perspective view of Figs. 1 and 2, the acoustic conversion piezoelectric 10, and the acoustic conversion piezoelectric 10 is attached to the center or The stacked first vibration plate 20, the supporter 30 fixed through the center of the acoustic transducer 10, the support frame 40 supporting the supporter 30, and the first vibration plate 20. The second vibration plate 50 is bonded to extend outwardly.

Herein, the acoustic transducer 10 may be attached to the surface or the rear surface of the first vibration plate 20.

The acoustic conversion piezoelectric 10 includes everything having a shape change, that is, a vibration causing structure according to a current change of a material surface, and may be made of a flat material or a flexible material in a flat structure.

When a voltage, in particular an alternating voltage, is applied to the acoustic conversion piezoelectric element 10, the bending vibration is caused, and the bending vibration is transmitted to the first vibration plate 20 to be described later, and a through hole 12 is formed at the center thereof. have.

The first vibration plate 20 is interlocked with the bending vibration of the acoustic transducer 10 to generate the bending vibration integrally, and a metal plate is applied.

The metal plate applied to the first vibrating plate 20 may be brass, aluminum, stainless steel, or the like, and a metal plate made of an individual, optionally combined alloy of the aforementioned materials may be applied.

As shown in FIG. 3A, the acoustic conversion piezoelectric body 10 and the first vibration plate 20 are attached or stacked, and the acoustic conversion piezoelectric body 10 is located at the center of the first vibration plate 20.

The configuration of the acoustic transducer 10 and the first vibration plate 20 is basically the same as the model of the sounding body using a conventional piezoelectric ceramic. However, for the bass region characteristics of the present invention, further special components to be described later are needed.

The supporter 30 is fixed through the center of the acoustic transducer 10.

Meanwhile, as illustrated in FIG. 3B, the center C of the first vibrating plate 20 may be attached or stacked eccentrically with the center C ′ of the acoustic transducer 10.

Again, the through hole 12 of the acoustic conversion piezoelectric power 10 through which the supporter 30 penetrates is formed larger than the diameter of the supporter 30.

However, the diameters of the through hole 12 and the supporter 30 are the same size or the through hole 12 is formed in a small size so that the through hole 12 and the supporter 30 are pressed into the through hole 10 and attached to each other. Since it may be possible, it is not limited to the size of the through-hole 12 mentioned above.

As shown in FIG. 3C, the supporter 30 may be closed again after passing through the first vibration plate 20, and the first vibration plate 20 may include the first vibration plate 20 and the supporter 30. The fixing hole 22 for firmly engaging is formed integrally. The fixing hole 22 is formed to have a size to achieve a press-fit or loose tolerance with the supporter 30, but after the supporter 30 is inserted, it is firmly coupled to each other with an adhesive or the like. In this case, as shown in FIG. 3B, the acoustic transducer 10 and the first vibrating plate 20 may be attached or installed with their centers eccentric.

An example of the state in which the supporter 30 is penetrated is a combination of the acoustic conversion piezoelectric 10, the first vibration plate 20, and the supporter 30 of FIG. 3C, as shown in FIG. 4 and as shown in the illustrated direction. The supporter 30 becomes a vibration point of the diaphragm 20, and both sides of the first vibration plate 20 are formed in the shape of a cantilever on the basis of the supporter 30 which is the vibration point.

Due to the shape of the cantilever, the first vibrating plate 20 vibrating along the acoustic transducer piezoelectrically vibrating when subjected to a constant voltage is not visible but repeats the concave or convex shape, which is advantageous for sound reproduction. Vibration and split vibration will occur.

When the first vibrating plate 20 vibrates on the assumption that only the supporter 30 is supported, the vibrating graph extends to infinity as shown in FIG. 5. Such a vibration graph is known to have good efficiency due to low resonant frequency characteristics and small mass of the acoustic transducer 10 as known in the speaker manufacturing industry, but is known to have very poor bass region characteristics.

, M은 진동계{음향변환압전기(10)와 제1진동판(20)}의 질량, S는 지지계{후술하는 서포터(30), 제2진동판(50)와 에지(60) 등}의 강성"와 같은 식으로 정의되고, 본 발명에 적용된 음향변환압전기(10)와 제1진동판(20)은 작은 부피 및 질량을 갖고 있으므로 공진주파수가 높아지게 된다.That is, the resonance frequency is "

Where M is the mass of the vibration system (acoustic transducer piezoelectric element 10 and the first vibration plate 20), and S is the rigidity of the support system {supporter 30, second vibration plate 50, edge 60, etc.} The sound conversion piezoelectric body 10 and the first vibrating plate 20 applied to the present invention are defined in the same manner as described above, and thus have a small volume and mass, thereby increasing the resonance frequency.

Thus, as is commonly known, the higher resonant frequency is disadvantageous for low frequency reproduction.

The present invention is to overcome the shortcomings of the acoustic transducer piezoelectric 10 and the first vibrating plate 20 as described above, that is, to overcome the small mass to faithfully reproduce the bass region, as shown in FIGS. As shown in FIG. 3C, a support frame 40 supporting the supporter 30 is installed.

The support frame 40 is coupled to the lower end of the supporter 30 and may be installed integrally or separately from the supporter 30.

Due to the structure of the supporter 30 and the support frame 40, the cantilever-type vibration can maintain a low resonance frequency characteristic generated through the first vibration plate 20 as described above, and use the low resonance frequency characteristic. By doing so, the bass range can be faithfully reproduced.

In addition, since the support frame 40 has a low value when the mass of the acoustic transducer 10 and the first vibrating plate 20 is constant as described above, the resonant frequency is lowered, so that the synthetic resin material is preferably applied. Not limited to this, a metal material may be applied.

Detailed description of the structure of the support frame 40 will be described in the description of the second vibration plate (50).

However, in the present invention, even if the first vibration plate 20 is supported through the supporter 30 and the support frame 40 as described above, the bending vibration may occur due to the vibration characteristics peculiar to the cantilever, so it must be controlled in a constant state.

The second vibration plate 50 for this purpose is to mechanically control the vibrations unique to the cantilever, that is, the bending vibration of the first vibration plate 20 to maintain the vibration of the first vibration plate 20 that may cause distortion at a low resonance frequency. .

The second vibrating plate 50 is provided with the first vibrating plate 20 and a heterogeneous material. The second vibrating plate 50 is attached to the outer circumferential surface of the first vibrating plate 20 and extends outward from the center of the first vibrating plate 20.

Here, the outer circumferential surface 24 of the first vibration plate 20 may be referred to as a predetermined portion of the upper surface or the bottom surface in the center direction from the outermost side surface where the first vibration plate 20 is finished.

As shown in FIG. 5, the second vibration plate 50 controls the vibration of the first vibration plate 20 which may extend indefinitely, thereby maintaining the sinusoidal vibration uniformly. Silver pulp, resin, bio-based, synthetic fiber, plastic, rayon, fabric blended with cotton and synthetic oil, carbon fiber, organic fiber, DuPont brand names Kevlar, NOMEX and Japan's Toyobo Co., Ltd. ZYLON and the like can be applied.

On the other hand, the above-mentioned support frame 40 further comprises an outer frame 42 formed at a higher position than the support frame 40. The support frame 40 supports the supporter 30, and the outer frame 42 is bonded to the outer circumferential surface 52 of the second vibration plate 50.

Here, the outer circumferential surface 52 of the second vibration plate 50 may be referred to as a predetermined portion of the upper surface or the bottom surface in the center direction from the outermost side surface where the second vibration plate 50 is finished.

At this time, the outer circumferential surface 52 of the second vibration plate 50 is an example as shown, but is closed in a plane. Such a flat finish is particularly advantageous as the planar area of the second vibration plate 50 is large, and is very useful for flat speaker that is finished in a plane.

Due to the adhesion as described above, the second vibration plate 50 connects them between the first vibration plate 20 and the support frame 40 and effectively controls the vertical vibration and the split vibration of the first vibration plate 20 to improve the mid-low range characteristics. This reinforces the bass region by controlling the low resonant frequency band to be reproduced.

On the other hand, the second vibration plate 50 may be implemented by modifying as shown in FIG. That is, the outer circumferential surface 52 of the second vibrating plate 50 is formed into a convex shape and then finished with a flat adhesive surface 54, and the adhesive surface 54 is bonded to the outer frame 42 of the support frame 40. Can be. In particular, although the convex shape shown above is protruding upward, the concave shape protrudes downward as shown in FIG. 7 (although not shown, the concave or convex shape of Fig. 6 is laterally multistage and corrugated). After being molded, it is finished to form a flat attachment surface.) After being molded, it is finished to form a flat adhesive surface 54 and the adhesive surface 54 may be adhered to the outer frame 42. However, when the outer circumferential surface 72 is flat as in FIGS. 1 to 4, the outer circumferential surface 74 is an adhesive surface.

Due to the molded shape of the second vibrating plate 50, the vertical vibration or split vibration of the second vibrating plate 50 can be ideally maintained, thereby maintaining the frequency characteristics and blocking the sound of the rear surface.

Naturally, the present invention can be carried out in various ways as described below.

8 further includes a dust cap 60 bonded to the second vibrating plate 50 or the first vibrating plate 20 at the central portion of the first vibrating plate 20 in the structures disclosed in FIGS. 1, 2, and 3a. .

The dust cap 60 may be made of plastic, felt, aluminum, pulp, fabric, or the like, and may be made of the same material as the second vibration plate 50 described above, and the shape thereof is a conventional shape commonly used in the speaker industry. As is known in the speaker industry, this prevents the control of properties and the ingress of foreign matter in the high-pitched region.

9A and 9B illustrate an example of an edge 70 applied to the present invention, and the edge 70 may be selectively applied among the structures disclosed in FIGS. 1 or 2, 3, and 8, and a second The outer circumferential surface 72 of the edge 70 also adheres to the outer circumferential surface 52 of the diaphragm 50 and extends in the outward direction, and thus, as shown in the outer circumferential surface 52 of the second vibration plate 50 shown in FIGS. 6 and 7. After forming a concave or convex, multi-stage corrugated form again to form a flat adhesive surface 74 is then finished or may be finished in a simple flat shape rather than a curved shape as described above.

At this time, the outer circumferential surface 52 of the second vibration plate 50 bonded to the inner circumferential surface 74 of the edge 70 has a flat shape.

Here, the outer circumferential surface 72 of the edge 70 may be referred to as an upper surface or a bottom surface in the center direction from the outermost side where the edge 70 is closed, and the adhesive surface 74, which is a bonded portion, has the curved shape. After the formation is a portion forming a predetermined plane, when the outer circumferential surface 72 is flat, the outer circumferential surface 74 is an adhesive surface.

In FIG. 9B, for example, the attachment surface 74 of the edge 70 is bonded to the outer frame 42 in a state in which the outer surface of the edge 70 protrudes in a convex shape and then finishes in a predetermined plane.

The edge 70 applied to the present invention is made of a material different from that of the second vibration plate 50, and supports unnecessary vertical vibration and division vibration of the second vibration plate 50 and absorbs and extinguishes vibration.

The present invention made of the above configuration, by using a sound conversion piezoelectric material made of a variety of materials to improve the mid- and low-band sound pressure characteristics that the piezoelectric speaker was not able to reproduce conventionally close to the characteristics of the existing magnetic circuit or voice coil type speaker ultra-thin Or it can be applied to various acoustic devices requiring light weight.

The scope of the present invention is shown by the scope of the claims, and is not limited by the specification text. Again, all variations and modifications belonging to the equivalent scope of the claims are within the scope of the present invention.

1 is a perspective view of a first embodiment of a piezoelectric speaker according to the present invention;

Figure 2 is an exploded perspective view of Figure 1;

3A is a partial cross-sectional view of FIG. 1.

Figure 3b is an embodiment showing another attached state of the acoustic transducer and the first vibration plate according to the present invention.

3c is another embodiment of a supporter according to the present invention.

4 and 5 are views showing a state in which the acoustic transducer and the first vibration plate applied to the present invention is supported by a supporter and bent and vibrated.

Figure 6 is another embodiment of a second vibration plate according to the present invention.

Figure 7 is another embodiment of the second vibration plate according to the present invention.

8 is another embodiment of a piezoelectric speaker according to the present invention.

9A is another embodiment of a piezoelectric speaker according to the present invention;

9B is an exploded perspective view of FIG. 9A;

* Description of the major symbols in the drawings *

10: acoustic conversion piezo 12: through hole

20: first vibration plate 22: fixing hole

30: supporter 40: support frame

42: outer frame 50: the second vibration plate

60: dust cap 70: edge

Claims (10)

Acoustic transducer piezoelectric, A first vibration plate attached to the center of the acoustic transducer, A supporter fixed through the center of the acoustic transducer; It includes a support frame for supporting the supporter, The support frame further comprises an outer frame, Piezoelectric speaker characterized in that it further comprises a second vibration plate which is bonded to the first vibration plate and extends in the outward direction, the outer peripheral surface is bonded to the outer frame. The method of claim 1, And a center of the acoustic transducer piezoelectric body and the center of the first vibration plate are eccentrically attached to each other. The method of claim 1, Piezoelectric speaker, characterized in that further comprising the dust cap is bonded to the second vibration plate. The method of claim 1, The second vibration plate is a piezoelectric speaker characterized in that the outer peripheral surface is made of convex or concave shape is finished. The method of claim 1, The second vibration plate is a piezoelectric speaker, characterized in that the outer peripheral surface is made of a flat surface. The method of claim 1, The second vibration plate is a piezoelectric speaker characterized in that it further comprises an edge which is bonded to the outer circumferential surface of the second vibration plate, the outer circumferential surface is formed in one of concave, convex, multi-stage corrugated shape after extending outward. The method of claim 6, The outer circumferential surface of any one of the concave, convex, multi-stage corrugated shape of the edge is a piezoelectric speaker characterized in that the concave, convex, multi-stage corrugated shape is formed to form a flat adhesive surface finish. The method of claim 6, The outer circumferential surface of the edge is a piezoelectric speaker characterized in that the finish is formed in a flat shape. The method according to any one of claims 1 to 6, The outer frame is a piezoelectric speaker characterized in that it is bonded with any one of the adhesive surface of the concave, convex, multi-stage corrugated shape of the edge. The method according to any one of claims 1 to 8, The outer frame is a piezoelectric speaker, characterized in that the flat outer peripheral surface of the edge is bonded.

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