Piezoelectric speaker

Abstract

A piezoelectric speaker is disclosed that increases sound pressure in the low-frequency range. The disclosed piezoelectric speaker includes a diaphragm that outputs sound based on mechanical deformation occurring in a piezoelectric element, and an adhesive member is attached to the diaphragm, wherein the adhesive member is attached to a portion of one surface of the diaphragm.

Description

Technology Field

[0001] The present invention relates to a piezoelectric speaker, and more specifically, to a piezoelectric speaker that can be installed in vehicle electronics, TVs, home appliances, etc. Background Technology

[0002] Recently, as the slimming down of portable devices such as mobile phones, smartphones, and laptops, as well as TV products including LED TVs, accelerates, piezoelectric speakers are attracting attention as an alternative to conventional dynamic speakers using magnetic coils.

[0003] Piezoelectric speakers are emerging as a leading future speaker technology due to their advantages of being thin, lightweight, and consuming less power compared to conventional dynamic speakers. In particular, there is a growing trend of actively exploring applications for piezoelectric speakers, as there are requirements for small, thin, and lightweight designs in mobile devices.

[0004] In addition, these piezoelectric speakers are installed in vehicle electronics or home appliances such as TVs to output specific sounds.

[0005] The matters described in the background technology above are intended to aid in understanding the background of the invention and may include matters that are not disclosed prior art. Prior art literature

[0006] Republic of Korea Published Patent No. 10-2023-0168421 (Automotive lamp capable of sound output and communication system using the same) The problem to be solved

[0007] The present invention is proposed in consideration of the aforementioned conventional circumstances, and aims to provide a piezoelectric speaker that increases sound pressure in the low-frequency range. means of solving the problem

[0008] To achieve the above objectives, a piezoelectric speaker according to a preferred embodiment of the present invention comprises a diaphragm that outputs sound based on mechanical deformation occurring in a piezoelectric element; wherein an adhesive member is attached to the diaphragm, and the adhesive member is attached to a part of one surface of the diaphragm.

[0009] One side of the adhesive member is attached to one side of the diaphragm, and the other side of the adhesive member can be attached to an adhesive member attachment target facing one side of the diaphragm.

[0010] The target for attachment of the above adhesive member may be a curved panel.

[0011] One side of the above diaphragm may be flat.

[0012] The above adhesive member may be two.

[0013] The two adhesive members mentioned above can be spaced apart from each other.

[0014] The two adhesive members may be a first adhesive member and a second adhesive member attached to an area excluding the central part of one surface of the diaphragm.

[0015] The central portion of one side of the above-mentioned diaphragm may be spaced apart from the adhesive member attachment target facing one side of the above-mentioned diaphragm.

[0016] The first adhesive member may be attached to one side of one surface of the diaphragm, and the second adhesive member may be attached to the other side of one surface of the diaphragm.

[0017] The above adhesive members may be three or more.

[0018] The above three or more adhesive members may be spaced apart from each other.

[0019] The above three or more adhesive members may be attached to an area excluding the central part of one surface of the diaphragm.

[0020] The area to which the adhesive member is attached may be 17% to 80% of the total area of ​​one side of the diaphragm.

[0021] The thickness of the adhesive member may be 100 μm to 300 μm.

[0022] The above adhesive member may be double-sided tape. Effects of the invention

[0023] According to the present invention with such a configuration, by attaching an adhesive member to one side of a piezoelectric speaker and making the attachment area of ​​the adhesive member smaller than the area of ​​one side of the piezoelectric speaker, excellent sound pressure characteristics are obtained, and in particular, the sound pressure in the low-frequency range can be significantly increased.

[0024] In particular, if the attachment area of ​​the partially attached adhesive member is made 80% or less of the surface area of ​​one side of the piezoelectric speaker, the effect of increasing sound pressure in the low-frequency range can be increased more significantly, and if the thickness of the partially attached adhesive member is also made 100 μm or more, the effect of increasing sound pressure in the low-frequency range can be increased more significantly. Brief explanation of the drawing

[0025] FIG. 1 is a drawing showing an example in which a piezoelectric speaker is installed according to an embodiment of the present invention. FIG. 2 is an enlarged view of part A shown in FIG. 1, and is a cross-sectional view showing the form in which a piezoelectric speaker according to an embodiment of the present invention is installed. FIG. 3 is a drawing for explaining an adhesive member attached to a piezoelectric speaker according to an embodiment of the present invention. FIG. 4 is a drawing for explaining the configuration of a piezoelectric speaker according to an embodiment of the present invention in more detail. Figure 5 is a graph comparing sound pressure when a piezoelectric speaker according to an embodiment of the present invention and a conventional piezoelectric speaker are each attached to a curved panel. Figure 6 is a graph comparing sound pressure according to the area of ​​the attachment tape when a piezoelectric speaker according to an embodiment of the present invention is attached to a curved panel in a partial attachment manner. Figure 7 is a graph comparing sound pressure according to the thickness of the attachment tape when a piezoelectric speaker according to an embodiment of the present invention is attached to a curved panel in a partial attachment manner. FIG. 8 is a graph comparing sound pressure when a piezoelectric speaker according to an embodiment of the present invention and a conventional piezoelectric speaker are each attached to a flat panel. Specific details for implementing the invention

[0026] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

[0027] The embodiments are provided to more fully explain the invention to those skilled in the art, and the following embodiments may be modified in various different forms, and the scope of the invention is not limited to the following embodiments. Rather, these embodiments are provided to make the disclosure more faithful and complete and to fully convey the spirit of the invention.

[0028] The terms used herein are for describing specific embodiments and are not intended to limit the invention. Additionally, the singular form in this specification may include the plural form unless the context clearly indicates otherwise. Terms such as “comprising,” “having,” and “having” in this application are intended to specify the presence of features, numbers, steps, actions, components, parts, or combinations thereof of the invention, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0029] In the description of the embodiments, where each layer (film), region, pattern, or structure is described as being formed "on" or "under" the substrate, each layer (film), region, pad, or pattern, "on" and "under" include both being formed "directly" and "indirectly" through another layer. In addition, the reference for the top or bottom of each layer is, in principle, based on the drawings.

[0030] The drawings are intended solely to facilitate an understanding of the concept of the present invention and should not be interpreted as limiting the scope of the invention. Additionally, relative thicknesses, lengths, or sizes in the drawings may be exaggerated for convenience and clarity of explanation.

[0031] FIG. 1 is a drawing showing an example in which a piezoelectric speaker is installed according to an embodiment of the present invention, FIG. 2 is an enlarged view of part A shown in FIG. 1, showing the form in which a piezoelectric speaker is installed according to an embodiment of the present invention in the form of a cross-sectional view, and FIG. 3 is a drawing for explaining an adhesive member attached to a piezoelectric speaker according to an embodiment of the present invention.

[0032] The piezoelectric effect refers to the phenomenon in which an electrical change occurs when pressure is applied to a piezoelectric material. Conversely, the phenomenon in which applying voltage to a piezoelectric material causes mechanical deformation, such as expansion and contraction, thereby inducing vibration, is called the inverse piezoelectric effect.

[0033] The piezoelectric speaker (20) according to an embodiment of the present invention utilizes the inverse piezoelectric effect.

[0034] More specifically, the piezoelectric speaker (20) according to an embodiment of the present invention forms a piezoelectric body using a piezoelectric material and produces sound by generating vibrations through repeated contraction and expansion by applying voltage to the piezoelectric body. Representative examples of such piezoelectric materials include ferroelectrics such as PZT ((Pb(Ti,Zr)O3)) and barium titanate (BaTiO3), and the piezoelectric body can be formed using these.

[0035] As illustrated in FIG. 1, a piezoelectric speaker (20) according to an embodiment of the present invention may be installed on the inner side of the front bumper (10) of a vehicle (100). When part A of FIG. 1 is enlarged, it may look like FIG. 2, which illustrates a schematic cross-sectional view of the piezoelectric speaker (20).

[0036] As shown in FIG. 2, a piezoelectric speaker (20) can be attached to the curved inner surface of the front bumper (10) of the vehicle (100). Here, the front bumper (10) of the vehicle (100) may be made of at least one material among metal and plastic, but is not limited thereto.

[0037] At this time, the piezoelectric speaker (20) can be installed (attached) to the inner surface of the front bumper (10), which is a curved panel, via an adhesive member (30a, 30b) such as double-sided tape.

[0038] At this time, the adhesive members (30a, 30b) are not attached (placed) entirely on one side of the piezoelectric speaker (20) (e.g., the side facing the inner side of the front bumper (10)), but are attached (placed) partially. That is, according to the embodiment, the adhesive members (30a, 30b) may be partially attached to the side facing the inner side of the front bumper (10) among the sides of the piezoelectric speaker (20) (e.g., which can be called the first side).

[0039] As illustrated in FIG. 3, the adhesive member (30a) can be attached to the left side of the first surface of the piezoelectric speaker (20) with a predetermined area and thickness, excluding the central part, and the adhesive member (30b) can be attached to the right side of the first surface of the piezoelectric speaker (20) with a predetermined area and thickness.

[0040] In this way, the adhesive members (30a, 30b) are partially attached (placed) on one side of the piezoelectric speaker (20) (e.g., the side facing the inner side of the front bumper (10)), so this is referred to as a partial attachment method in the specification of the present invention.

[0041] The adhesive member (30a) described above may be an example of the first adhesive member described in the claims of the present invention, and the adhesive member (30b) may be an example of the second adhesive member described in the claims of the present invention. Also, the first surface of the piezoelectric speaker (20) may be described as one surface of the piezoelectric speaker described in the claims of the present invention.

[0042] In the preceding description, the piezoelectric speaker (20) is installed on the curved inner surface of the front bumper (10) of the vehicle (100) via adhesive members (30a, 30b), but it may also be installed on a curved panel other than the front bumper (10) of the vehicle (100) as needed. Additionally, the piezoelectric speaker (20) may be installed on a flat panel instead of a curved panel.

[0043] In the above-described FIGS. 1 to 3, a single piezoelectric speaker (20) is installed on the curved inner surface of the front bumper (10) of the vehicle (100), but if necessary, a plurality of piezoelectric speakers (20) may be installed.

[0044] Meanwhile, although the above description describes the piezoelectric speaker (20) as being installed on the curved inner surface of the front bumper (10) of the vehicle, the piezoelectric speaker (20) may also be installed on a display device (e.g., a display panel) of a TV appliance as needed.

[0045] FIG. 4 is a drawing for explaining the configuration of a piezoelectric speaker (20) according to an embodiment of the present invention in more detail.

[0046] The piezoelectric speaker (20) includes an electrode (21), a piezoelectric element (22), and a diaphragm (23).

[0047] The piezoelectric element (22) may be composed of a single layer or a stacked structure. For example, the piezoelectric element (22) may be formed into a thin single-layer film by performing a polishing process on a thick-film piezoelectric ceramic, or formed by depositing or coating a film of a stacked structure. Since the process of manufacturing the piezoelectric element (20) is a well-known technique that can be sufficiently understood by those working in the same industry, a detailed description thereof is omitted.

[0048] The piezoelectric element (22) can convert an electrical signal into a physical vibration (i.e., mechanical vibration) using the inverse piezoelectric effect.

[0049] The piezoelectric element (22) may include not only polycrystalline ceramics such as PZT, but also single-crystal piezoelectric materials such as PMN-PT, PZN-PT, PIN-PT, and PYN-PT, flexible piezoelectric polymer materials such as PVDF and PVDF-TrFE, and lead-free piezoelectric novel materials such as BNT (BaNiTiO3) and BZT-BCT. Additionally, the piezoelectric element (22) may have various shapes such as rectangular, circular, elliptical, and polygonal shapes, in addition to square shapes.

[0050] The piezoelectric element (22) is polarized. That is, when an electric signal (e.g., alternating voltage) is applied to the polarized piezoelectric element (22), the piezoelectric element (22) undergoes mechanical deformation such as expansion and contraction.

[0051] The electrode (21) can be formed on the upper surface or upper and lower surfaces of the piezoelectric body (22) and can apply an electrical signal to the piezoelectric body (22). In FIG. 4, the electrode (21) is exemplified as being formed on the upper surface and lower surface of the piezoelectric body (22), respectively. The electrode (21) includes a first electrode (21a) and a second electrode (21b), wherein the first electrode (21a) can be formed on the upper surface of the piezoelectric body (22) and the second electrode (21b) can be formed on the lower surface of the piezoelectric body (22).

[0052] The electrodes (21a, 21b) may be made of an opaque metal material with excellent low resistance and heat dissipation properties, but are not limited thereto. In some cases, they may be made of a transparent conductive material or a conductive polymer material.

[0053] In addition, the first electrode (21a) and the second electrode (21b) can be formed in various shapes including squares, rectangles, and sectors.

[0054] The diaphragm (23) can be installed on one side of the piezoelectric body (22) on which electrodes (21a, 21b) are formed. For example, the diaphragm (23) can be installed (attached) to the piezoelectric body (22) via the second electrode (21b).

[0055] The diaphragm (23) receives mechanical deformation generated from the piezoelectric element (22) and generates a predetermined vibration, and accordingly, a density wave is formed on the front side of the diaphragm (23) to output a predetermined sound (acoustic).

[0056] Sound or sound waves refer to the phenomenon in which vibrations generated from a sound source cause periodic changes in air pressure and propagate in the form of compression waves.

[0057] In other words, the diaphragm (23) can be seen as playing a role in converting the vibration generated from the piezoelectric element (22) into a change in air pressure.

[0058] The adhesive member (30a, 30b) may be composed of a conductive or non-conductive double-sided tape or a conductive or non-conductive adhesive.

[0059] In an embodiment of the present invention, one side of the adhesive member (30a, 30b) is attached to one side of the diaphragm (23), and the other side of the adhesive member (30a, 30b) may be attached to an adhesive member attachment target facing one side of the diaphragm (23). The adhesive member (30a) may be the first adhesive member described in the claims of the present invention, and the adhesive member (30b) may be the second adhesive member described in the claims of the present invention.

[0060] Here, the target for attaching the adhesive member is preferably a curved panel, for example, the inner surface (i.e., the curved portion) of the front bumper (10) of a vehicle (10). At this time, it is preferable that the diaphragm (23) facing the target for attaching the adhesive member is not bent (i.e., not convex or concave). In particular, it is preferable that one side of the diaphragm (23) facing the target for attaching the adhesive member is flat. In other words, in an embodiment of the present invention, one side of the diaphragm (23) is flat, but it is preferable that the piezoelectric speaker (20) itself is formed in a flat shape as shown in FIG. 2.

[0061] Referring to FIG. 4, the adhesive members (30a, 30b) are spaced apart from each other and can be attached to an area excluding the central part of one side of the diaphragm (23). For example, the adhesive member (30a) can be attached to one side of one side of the diaphragm (23), and the adhesive member (30b) can be attached to the other side of one side of the diaphragm (23). Here, the one side may refer to a portion that occupies a predetermined area toward the central part by contacting one end of one side of the diaphragm (23) as in FIG. 4, and the other side may refer to a portion that occupies a predetermined area toward the central part by contacting the other end of one side of the diaphragm (23) as in FIG. 4. Alternatively, one side may refer to a portion that occupies a predetermined area from near one end of one surface of the diaphragm (23) toward the center without contacting one end of one surface, and the other side may refer to a portion that occupies a predetermined area from near the other end of one surface of the diaphragm (23) toward the center without contacting the other end of one surface.

[0062] Due to the adhesive members (30a, 30b) attached in this manner, the central part of one side of the diaphragm (23) is separated from the adhesive member attachment target facing the one side of the diaphragm (23).

[0063] In FIG. 4 described above, two adhesive members were used, but three or more may be used if necessary. If it is assumed that four adhesive members are used, for example, the adhesive member (30a) can be divided into two parts spaced apart from each other, and the adhesive member (30b) can be divided into two parts spaced apart from each other. For instance, the two-part adhesive member (30a) can be attached to one side of one surface of the diaphragm (23), and the two-part adhesive member (30b) can be attached to the other side of one surface of the diaphragm (23). Even when three or more adhesive members are used in this manner, it is preferable that the three or more adhesive members be attached to an area excluding the central part of one surface of the diaphragm (23).

[0064] The piezoelectric speaker (20) of FIG. 4 described above can generate mechanical vibration (displacement or deformation) according to an electrical signal applied through electrodes (21a, 21b).

[0065] That is, when an alternating voltage is applied to the upper electrode (21a) and lower electrode (21b) of the piezoelectric element (22), the piezoelectric element (22) alternately contracts and expands, and as a result, the diaphragm (23) undergoes deformation such as bending, and due to the bending phenomenon in which the bending direction changes alternately, the diaphragm (23) creates vibrations and can output a predetermined sound (acoustic).

[0066] In other words, when the piezoelectric element (22) of the piezoelectric speaker (20) receives an electric signal and generates mechanical vibration, the mechanical vibration is converted into a change in air pressure through the diaphragm (23) to generate (output) sound.

[0067] Figure 5 is a graph comparing sound pressure when a piezoelectric speaker according to an embodiment of the present invention and a conventional piezoelectric speaker are each attached to a curved panel.

[0068] Generally, higher frequencies produce louder sounds, while lower frequencies produce quieter sounds; the intensity of sound emitted from an object in this manner is called sound pressure.

[0069] A piezoelectric speaker according to an embodiment of the present invention and a conventional piezoelectric speaker were tested after being attached along the curved surface of the inner side of a curved panel.

[0070] In addition, the piezoelectric speaker according to the embodiment of the present invention has adhesive members (30a, 30b) attached in a partial attachment manner, whereas the conventional piezoelectric speaker has adhesive members attached in a full attachment manner (e.g., a method of attaching to cover one side of the diaphragm entirely).

[0071] When comparing the sound pressure of the piezoelectric speaker (20) according to the embodiment of the present invention with that of a conventional piezoelectric speaker, as shown in FIG. 5, it was found that the sound pressure of the piezoelectric speaker (20) according to the embodiment of the present invention was slightly lower in the high-frequency range compared to the conventional piezoelectric speaker, but the sound pressure in the low-frequency range was significantly increased.

[0072] That is, in the piezoelectric speaker (20) according to the embodiment of the present invention, as adhesive members (30a, 30b) are attached in a partial attachment manner, the curved panel (e.g., the curved portion of the front bumper (10) of the vehicle; see FIG. 2) and the central portion of the piezoelectric speaker (20) (more specifically, the central portion of one side of the diaphragm (23)) act as a resonating plate, and it was found that the sound pressure in the low-frequency range was significantly increased through this resonating plate function.

[0073] Figure 6 is a graph comparing sound pressure according to the area of ​​the attachment tape when a piezoelectric speaker according to an embodiment of the present invention is attached to a curved panel in a partial attachment manner.

[0074] Here, the area of ​​the adhesive tape (i.e., the area occupied by the adhesive members (30a, 30b)) is given by the following formula,

[0075] The area of ​​the adhesive tape (%) can be calculated as “area of ​​both adhesive tapes / total area of ​​the first surface of the piezoelectric speaker (20)”.

[0076] The first surface mentioned above is a surface facing the inner surface of the curved panel among the surfaces of the piezoelectric speaker (20), and more specifically, may refer to one surface of the diaphragm (23) facing the inner surface of the curved panel. Both attachment areas may refer to the sum of the individual attachment areas occupied by the first adhesive member (30a) and the second adhesive member (30b), respectively, on the first surface of the piezoelectric speaker (20) (more specifically, one surface of the diaphragm (23) facing the inner surface of the curved panel).

[0077] The piezoelectric speaker (20) according to the embodiment of the present invention using a partial attachment method has an effect of increasing sound pressure in the low-frequency range compared to a conventional piezoelectric speaker using a full attachment method. As shown in FIG. 6, it was found that when the attachment tape area is approximately 80% or less (more preferably, when it is approximately 17% to 80%), the effect of increasing sound pressure in the low-frequency range is greater.

[0078] In an embodiment of the present invention, for the effect of increasing sound pressure in the low-frequency range, it is preferable that the adhesive members (30a, 30b) have an attachment area smaller than the area of ​​the first surface of the piezoelectric speaker (20). That is, it is preferable that the adhesive members (30a, 30b) be attached to an area smaller than the area of ​​one surface of the diaphragm (23) facing the inner surface of the curved panel.

[0079] In other words, an adhesive member (30a, 30b) is attached to one side of the piezoelectric speaker (20) according to an embodiment of the present invention, and the total attachment area of ​​the adhesive member (30a, 30b) (i.e., the attachment tape area) is smaller than the area of ​​one side of the diaphragm (23). That is, in order to increase the effect of increasing sound pressure in the low-frequency range, it was found through the graph of FIG. 6 that it is most preferable for the sum of the attachment area of ​​the adhesive member (30a) and the attachment area of ​​the adhesive member (30b) to be 17% to 80% of the total area of ​​the first side of the piezoelectric speaker (20).

[0080] Figure 7 is a graph comparing sound pressure according to the thickness of the attachment tape when a piezoelectric speaker according to an embodiment of the present invention is attached to a curved panel in a partial attachment manner.

[0081] That is, FIG. 7 is a sound pressure comparison graph for a first piezoelectric speaker with adhesive members (30a, 30b) with a thickness of 100 μm attached, a second piezoelectric speaker with adhesive members (30a, 30b) with a thickness of 200 μm attached, and a third piezoelectric speaker with adhesive members (30a, 30b) with a thickness of 300 μm attached. At this time, the total attachment area of ​​the adhesive members (30a, 30b) attached to the first piezoelectric speaker, the total attachment area of ​​the adhesive members (30a, 30b) attached to the second piezoelectric speaker, and the total attachment area of ​​the adhesive members (30a, 30b) attached to the third piezoelectric speaker are considered to be the same as each other.

[0082] As a result of testing three partial attachment type piezoelectric speakers (20) as described above, it was found that when the thickness of the adhesive members (30a, 30b) during partial attachment is approximately 100 μm or more (more preferably, approximately 100 μm to 300 μm), the effect of increasing sound pressure in the low-frequency range is greater.

[0083] FIG. 8 is a graph comparing sound pressure when a piezoelectric speaker according to an embodiment of the present invention and a conventional piezoelectric speaker are each attached to a flat panel.

[0084] A piezoelectric speaker according to an embodiment of the present invention was tested by attaching adhesive members (30a, 30b) in a partial attachment manner, and a conventional piezoelectric speaker was tested by attaching adhesive members in a full attachment manner (e.g., a method of attaching to cover one side of a diaphragm entirely).

[0085] Even when testing the piezoelectric speaker according to an embodiment of the present invention and a conventional piezoelectric speaker after attaching them to a flat panel, as shown in FIG. 8, it was found that an increase in sound pressure in the low-frequency range is possible when partially attached, depending on the size of the flat panel and the size of the piezoelectric speaker (more specifically, the size of the diaphragm).

[0086] The foregoing description is merely an illustrative explanation of the technical concept of the present invention, and those skilled in the art to which the present invention pertains will be able to make various modifications and variations within the scope of the essential characteristics of the present invention. Accordingly, the embodiments disclosed in the present invention are intended to explain, not limit, the technical concept of the present invention, and the scope of the technical concept of the present invention is not limited by these embodiments. The scope of protection of the present invention shall be interpreted by the claims below, and all technical concepts within an equivalent scope shall be interpreted as being included within the scope of rights of the present invention. Explanation of the symbols

[0087] 10: Front bumper 20: Piezoelectric speaker 21: Electrode 21a: First electrode 21b: Second electrode 22: Piezoelectric element 23: Diaphragm 30a, 30b: Adhesive member 100 : Vehicle

Claims

Claim 1 A piezoelectric speaker comprising: a diaphragm that outputs sound based on mechanical deformation occurring in a piezoelectric element; wherein an adhesive member is attached to the diaphragm, wherein one surface of the adhesive member is attached to one surface of the diaphragm and the other surface of the adhesive member is attached to an adhesive member attachment target facing the diaphragm, wherein one surface of the diaphragm is flat and the adhesive member attachment target is a curved panel, and the adhesive member is attached to an area excluding the central part of one surface of the diaphragm, such that the central part is spaced apart from the adhesive member attachment target. Claim 2 delete Claim 3 delete Claim 4 delete Claim 5 In claim 1, the adhesive member is two, a piezoelectric speaker. Claim 6 In claim 5, the two adhesive members are spaced apart from each other, piezoelectric speakers. Claim 7 In claim 5, the two adhesive members are a first adhesive member and a second adhesive member attached to an area excluding the central part of one surface of the diaphragm, a piezoelectric speaker. Claim 8 delete Claim 9 A piezoelectric speaker according to claim 7, wherein the first adhesive member is attached to one side of one surface of the diaphragm and the second adhesive member is attached to the other side of one surface of the diaphragm. Claim 10 A piezoelectric speaker according to claim 1, wherein the adhesive member is three or more. Claim 11 In claim 10, the three or more adhesive members are spaced apart from each other, forming a piezoelectric speaker. Claim 12 In claim 10, the three or more adhesive members are attached to an area excluding the central part of one surface of the diaphragm, in a piezoelectric speaker. Claim 13 delete Claim 14 A piezoelectric speaker according to claim 1, wherein the area to which the adhesive member is attached is 17% to 80% of the total area of ​​one surface of the diaphragm. Claim 15 A piezoelectric speaker according to claim 1, wherein the thickness of the adhesive member is 100 μm to 300 μm. Claim 16 A piezoelectric speaker according to claim 1, wherein the adhesive member is double-sided tape.

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