Piezoelectric speaker

Abstract

A piezoelectric speaker for increasing a sound pressure level in a low-frequency range is disclosed. The disclosed piezoelectric speaker comprises a vibration plate for outputting sound on the basis of mechanical deformation that occurs in a piezoelectric body, wherein the adhesive member is attached to the vibration plate, and the adhesive member is attached to a portion of one surface of the vibration plate.

Description

piezoelectric speaker

[0001] The present invention relates to a piezoelectric speaker, and more specifically, to a piezoelectric speaker that can be installed in vehicle electrical equipment and TV home appliances.

[0002] As the slimming of portable devices such as cell phones, smart phones, and laptops, as well as TV products including LED TVs, has accelerated, piezoelectric speakers are attracting attention as an alternative to dynamic speakers using existing magnetic coils.

[0003] Piezoelectric speakers are emerging as a future-leading speaker technology, boasting the advantages of being thinner, lighter, and consuming less power than conventional dynamic speakers. In particular, mobile devices demand compactness, thinness, and lightness, leading to active exploration of piezoelectric speaker applications.

[0004] Additionally, these piezoelectric speakers are installed in vehicle electrical systems or TV appliances to output certain sounds.

[0005] The matters described in the background art above are intended to help understand the background of the invention and may include matters that are not publicly disclosed prior art.

[0006] The present invention has been proposed in consideration of the above-mentioned conventional circumstances, and its purpose is to provide a piezoelectric speaker that increases sound pressure in the low-frequency range.

[0007] In order to achieve the above purpose, a piezoelectric speaker according to a preferred embodiment of the present invention includes a diaphragm that outputs sound based on mechanical deformation occurring in a piezoelectric body; and an adhesive member is attached to the diaphragm, wherein the adhesive member is attached to a portion of one surface of the diaphragm.

[0008] One side of the adhesive member may be attached to one side of the vibration plate, and the other side of the adhesive member may be attached to an adhesive member attachment target facing one side of the vibration plate.

[0009] The target of attachment of the above adhesive member may be a curved panel.

[0010] One side of the above vibration plate may be flat.

[0011] There may be two of the above adhesive members.

[0012] The above two adhesive members can be spaced apart from each other.

[0013] The above two adhesive members may be a first adhesive member and a second adhesive member attached to an area excluding the central portion of one side of the vibration plate.

[0014] The central portion of one side of the above-mentioned vibration plate may be spaced apart from the object to which the adhesive member is attached facing one side of the above-mentioned vibration plate.

[0015] The first adhesive member may be attached to one side of one surface of the vibration plate, and the second adhesive member may be attached to the other side of one surface of the vibration plate.

[0016] There may be three or more of the above adhesive members.

[0017] The above three or more adhesive members may be spaced apart from each other.

[0018] The three or more adhesive members described above can be attached to an area excluding the central portion of one side of the vibration plate.

[0019] The area to which the above adhesive member is attached may be 17% to 80% of the total area of ​​one side of the above vibration plate.

[0020] The thickness of the above adhesive member may be 100 μm to 300 μm.

[0021] The above adhesive material may be a double-sided tape.

[0022] According to the present invention of this 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, sound pressure in the low-frequency range can be significantly increased.

[0023] In particular, if the attachment area of ​​the partially attached adhesive member is less than 80% of the area of ​​one side of the piezoelectric speaker, the effect of increasing the sound pressure in the low-frequency range can be further increased, and if the thickness of the partially attached adhesive member is also more than 100 μm, the effect of increasing the sound pressure in the low-frequency range can be further increased.

[0024] Fig. 1 is a drawing showing an example in which a piezoelectric speaker according to an embodiment of the present invention is installed.

[0025] FIG. 2 is an enlarged view of part A shown in FIG. 1, and is a cross-sectional view showing a form in which a piezoelectric speaker according to an embodiment of the present invention is installed.

[0026] FIG. 3 is a drawing for explaining an adhesive member attached to a piezoelectric speaker according to an embodiment of the present invention.

[0027] FIG. 4 is a drawing for explaining in more detail the configuration of a piezoelectric speaker according to an embodiment of the present invention.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] Figure 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.

[0032] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0033] These examples are provided to more fully illustrate the present invention to those skilled in the art. The following examples may be modified in various ways, and the scope of the present invention is not limited to the examples described below. Rather, these examples are provided to further faithfully and completely convey the spirit of the present invention.

[0034] The terminology used herein is used to describe specific embodiments and is not intended to limit the present invention. In addition, the singular form in this specification may include the plural form unless the context clearly indicates otherwise. It should be understood that the terms "comprise," "include," and "have" in this application are intended to specify the presence of a feature, number, step, operation, component, part, or combination thereof of the invention, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0035] In the description of the embodiments, when 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" or "indirectly" through another layer. In addition, the reference for above or below each layer is, in principle, based on the drawing.

[0036] The drawings are intended solely to facilitate understanding of the invention and should not be construed as limiting the scope of the invention. Furthermore, relative thicknesses, lengths, and sizes in the drawings may be exaggerated for convenience and clarity of explanation.

[0037] FIG. 1 is a drawing showing an example in which a piezoelectric speaker according to an embodiment of the present invention is installed, FIG. 2 is an enlarged view of part A shown in FIG. 1, which is a drawing showing a cross-sectional view of a form in which a piezoelectric speaker according to an embodiment of the present invention is installed, and FIG. 3 is a drawing for explaining an adhesive member attached to a piezoelectric speaker according to an embodiment of the present invention.

[0038] The piezoelectric effect is a phenomenon in which an electrical change occurs when pressure is applied to a piezoelectric material. Conversely, the phenomenon in which mechanical deformation such as expansion and contraction occurs when voltage is applied to a piezoelectric material, causing vibrations, is called the converse piezoelectric effect.

[0039] The piezoelectric speaker (20) according to an embodiment of the present invention utilizes the reverse piezoelectric effect.

[0040] More specifically, the piezoelectric speaker (20) according to an embodiment of the present invention forms a piezoelectric body with a piezoelectric material, and generates vibrations and sounds by repeatedly performing contraction and expansion by applying voltage to the piezoelectric body. Representative examples of such piezoelectric materials include ferroelectric PZT ((Pb(Ti,Zr)O3), barium titanate (BaTiO3), etc., and these can be used to form a piezoelectric body.

[0041] As illustrated in Fig. 1, a piezoelectric speaker (20) according to an embodiment of the present invention can be installed on the inner side of the front bumper (10) of a vehicle (100). An enlarged view of part A of Fig. 1 may be similar to Fig. 2, which illustrates a schematic cross-sectional state of the piezoelectric speaker (20).

[0042] As shown in Fig. 2, the piezoelectric speaker (20) can be attached to the curved surface of the inner side of the front bumper (10) of the vehicle (100). Here, the front bumper (10) of the vehicle (100) can include at least one material among metal and plastic, but is not limited thereto.

[0043] 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, using an adhesive material (30a, 30b) such as double-sided tape.

[0044] At this time, the adhesive members (30a, 30b) are not entirely attached (placed) to one side of the piezoelectric speaker (20) (e.g., the side facing the inner side of the front bumper (10)), but are partially attached (placed). That is, depending on the embodiment, the adhesive members (30a, 30b) may be partially attached to a side (e.g., a first side) of the sides of the piezoelectric speaker (20) facing the inner side of the front bumper (10).

[0045] As illustrated in Fig. 3, the adhesive member (30a) can be attached with a predetermined area and thickness to the left side of the first surface of the piezoelectric speaker (20) excluding the central portion, and the adhesive member (30b) can be attached with a predetermined area and thickness to the right side of the first surface of the piezoelectric speaker (20) excluding the central portion.

[0046] In this way, the adhesive member (30a, 30b) is partially attached (placed) to one side of the piezoelectric speaker (20) (e.g., the side facing the inner side of the front bumper (10)), and therefore, in the specification of the present invention, this is referred to as a partial attachment method.

[0047] The above-described adhesive member (30a) 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. In addition, the first surface of the piezoelectric speaker (20) may be referred to as one surface of the piezoelectric speaker described in the claims of the present invention.

[0048] In the above description, the piezoelectric speaker (20) is installed on the curved surface of the inner side of the front bumper (10) of the vehicle (100) via an adhesive member (30a, 30b), but it may be installed on a curved panel other than the front bumper (10) of the vehicle (100) as needed. In addition, the piezoelectric speaker (20) may be installed on a flat panel rather than a curved panel.

[0049] In the above-described drawings 1 to 3, one piezoelectric speaker (20) is installed on the curved surface of the inner side of the front bumper (10) of the vehicle (100), but a plurality of piezoelectric speakers (20) may be installed as needed.

[0050] Meanwhile, in the above description, the piezoelectric speaker (20) is described as being installed on the curved surface of the inner side of the front bumper (10) of the vehicle, but if necessary, the piezoelectric speaker (20) may also be installed on a display device (e.g., a display panel) of a TV appliance.

[0051] FIG. 4 is a drawing for explaining in more detail the configuration of a piezoelectric speaker (20) according to an embodiment of the present invention.

[0052] A piezoelectric speaker (20) includes an electrode (21), a piezoelectric body (22), and a vibration plate (23).

[0053] The piezoelectric material (22) may be configured as a single-layer or laminated structure. For example, the piezoelectric material (22) may be formed into a thin single-layer film by performing a polishing process on a thick-film piezoelectric ceramic, or may be formed by depositing or coating a laminated film. The process of manufacturing the piezoelectric material (20) is well known to those in the industry and is therefore not described in detail.

[0054] A piezoelectric material (22) can convert an electric signal into a physical vibration (i.e., mechanical vibration) by using the inverse piezoelectric effect.

[0055] The piezoelectric material (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 new materials such as BNT (BaNiTiO3) and BZT-BCT. In addition, the piezoelectric material (22) may have various shapes such as not only square but also rectangular, circular, oval, and polygonal.

[0056] The piezoelectric material (22) is polarized. That is, when an electric signal (e.g., an AC voltage) is applied to the polarized piezoelectric material (22), the piezoelectric material (22) undergoes mechanical deformation such as expansion and contraction.

[0057] The electrode (21) can be formed on the upper or lower surface of the piezoelectric body (22), and can apply an electric signal to the piezoelectric body (22). In Fig. 4, it is exemplified that the electrode (21) is formed on the upper and lower surfaces of the piezoelectric body (22), respectively. The electrode (21) includes a first electrode (21a) and a second electrode (21b), and 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).

[0058] The electrodes (21a, 21b) may be made of an opaque metal material with low resistance and excellent 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.

[0059] Additionally, the first electrode (21a) and the second electrode (21b) can be formed in various shapes including square, rectangular, and fan-shaped shapes.

[0060] The vibration plate (23) can be installed on one surface of the piezoelectric body (22) on which the electrodes (21a, 21b) are formed. For example, the vibration plate (23) can be installed (attached) to the piezoelectric body (22) via the second electrode (21b).

[0061] The vibration plate (23) receives mechanical deformation generated from the piezoelectric body (22) and generates a predetermined vibration, and accordingly, a dense wave is formed in the front side of the vibration plate (23) to output a predetermined sound (acoustic sound).

[0062] Sound or sound wave is a phenomenon in which vibrations generated from a sound source cause periodic changes in air pressure and propagate in the form of dense waves.

[0063] That is, it can be seen that the vibration plate (23) plays a role in converting the vibration generated from the piezoelectric body (22) into a change in air pressure.

[0064] The adhesive member (30a, 30b) may be composed of a conductive or non-conductive double-sided tape or a conductive or non-conductive adhesive.

[0065] In an embodiment of the present invention, one surface of the adhesive member (30a, 30b) may be attached to one surface of the vibration plate (23), and the other surface of the adhesive member (30a, 30b) may be attached to an adhesive member attachment target facing one surface of the vibration plate (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.

[0066] Here, the object to which the adhesive member is attached is preferably a curved panel, and for example, it can be the inner surface (i.e., curved portion) of the front bumper (10) of the vehicle (10). At this time, it is preferable that the diaphragm (23) facing the object to which the adhesive member is attached is not bent (i.e., not convex or concave). In particular, it is preferable that one surface of the diaphragm (23) facing the object to which the adhesive member is attached is flat. In other words, in the embodiment of the present invention, one surface of the diaphragm (23) is also flat, but it is preferable that the piezoelectric speaker (20) itself is formed in a flat shape, as in FIG. 2.

[0067] 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 portion of one side of the vibration plate (23). For example, the adhesive member (30a) can be attached to one side of one side of the vibration plate (23), and the adhesive member (30b) can be attached to the other side of one side of the vibration plate (23). Here, the one side may refer to a portion that is in contact with one end of one side of the vibration plate (23) and occupies a predetermined area toward the central portion, as shown in Fig. 4, and the other side may refer to a portion that is in contact with the other end of one side of the vibration plate (23) and occupies a predetermined area toward the central portion, as shown in Fig. 4. Alternatively, the one side may mean a region that does not contact one end of one side of the vibration plate (23) and occupies a predetermined area near the one end toward the center, and the other side may mean a region that does not contact the other end of one side of the vibration plate (23) and occupies a predetermined area near the other end toward the center.

[0068] Due to the adhesive member (30a, 30b) attached in this way, the central portion of one side of the vibration plate (23) is spaced apart from the object to which the adhesive member is attached facing one side of the vibration plate (23).

[0069] In the above-described drawing 4, the adhesive member is described as being two, but three or more may be used if necessary. If it is assumed that the adhesive member is composed of four pieces, for example, the adhesive member (30a) may be divided into two and spaced apart from each other, and the adhesive member (30b) may be divided into two and spaced apart from each other. For example, the divided adhesive member (30a) may be attached to one side of one surface of the diaphragm (23), and the divided adhesive member (30b) may be attached to the other side of one surface of the diaphragm (23). Even when the adhesive member is composed of three or more pieces, it is preferable that the three or more adhesive members be attached to an area excluding the central portion of one surface of the diaphragm (23).

[0070] The piezoelectric speaker (20) of FIG. 4 as described above can generate mechanical vibration (displacement or deformation) according to an electric signal applied through the electrodes (21a, 21b).

[0071] That is, when an alternating voltage is applied to the upper electrode (21a) and the lower electrode (21b) of the piezoelectric body (22), the piezoelectric body (22) alternately repeats contraction and expansion, thereby causing the diaphragm (23) to undergo deformation such as bending, and the diaphragm (23) can generate vibrations and output a predetermined sound (acoustic) due to the bending phenomenon in which the bending direction alternates.

[0072] In other words, when the piezoelectric body (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.

[0073] 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.

[0074] Normally, the higher the frequency, the louder the sound, and the lower the frequency, the quieter the sound. The intensity of sound coming from an object is called sound pressure.

[0075] A piezoelectric speaker according to an embodiment of the present invention and a conventional piezoelectric speaker were attached along the curved surface of the inner surface of a curved panel and then tested.

[0076] In addition, the piezoelectric speaker according to the embodiment of the present invention has the adhesive member (30a, 30b) attached in a partial attachment manner, while the conventional piezoelectric speaker has the adhesive member attached in a full attachment manner (e.g., a method of attaching the adhesive member so as to cover the entire surface of the diaphragm).

[0077] When comparing the sound pressure of a piezoelectric speaker (20) according to an embodiment of the present invention with that of a conventional piezoelectric speaker, as shown in FIG. 5, it can be seen that the sound pressure of the piezoelectric speaker (20) according to an embodiment of the present invention is somewhat lower in the high-pitched range than that of a conventional piezoelectric speaker, but the sound pressure of the low-pitched range is significantly higher.

[0078] That is, in the piezoelectric speaker (20) according to the embodiment of the present invention, since the 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)) functioned as a sounding board, and it was found that the sound pressure in the low-pitched range was significantly increased through this function of the sounding board.

[0079] 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.

[0080] Here, the area of ​​the attachment tape (i.e., the area occupied by the adhesive member (30a, 30b)) is expressed by the following formula:

[0081] "Attachment tape area (%) = Attachment area on both sides / Total area of ​​the first side of the piezoelectric speaker (20)" can be obtained.

[0082] The first surface mentioned above is a surface of the piezoelectric speaker (20) that faces the inner side of the curved panel, and more specifically, may refer to a surface of the vibration plate (23) that faces the inner side of the curved panel. The double-sided attachment area may refer to an area that is the sum of the individual attachment areas occupied by the first adhesive member (30a) and the second adhesive member (30b) on the first surface of the piezoelectric speaker (20) (more specifically, a surface of the vibration plate (23) that faces the inner side of the curved panel).

[0083] The piezoelectric speaker (20) according to the embodiment of the present invention using a partial attachment method has a sound pressure increase effect in the low-frequency range compared to a conventional piezoelectric speaker using a front attachment method. As shown in FIG. 6, it was found that the sound pressure increase effect in the low-frequency range was greater when the attachment tape area was approximately 80% or less (more preferably, approximately 17% to 80%).

[0084] In an embodiment of the present invention, in order to increase the sound pressure in the low-frequency range, it is preferable that the adhesive member (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 member (30a, 30b) is attached to an area smaller than the area of ​​one surface of the diaphragm (23) facing the inner surface of the curved panel.

[0085] In other words, adhesive members (30a, 30b) are attached to one surface of the piezoelectric speaker (20) according to the embodiment of the present invention, and the total attachment area (i.e., attachment tape area) of the adhesive members (30a, 30b) is smaller than the area of ​​one surface of the diaphragm (23). That is, in order to increase the effect of increasing the sound pressure in the low-frequency range, it can be seen from the graph of Fig. 6 that the sum of the attachment areas of the adhesive members (30a) and the attachment areas of the adhesive members (30b) is most preferably 17% to 80% of the total area of ​​the first surface of the piezoelectric speaker (20).

[0086] 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.

[0087] That is, Fig. 7 is a sound pressure comparison graph for a first piezoelectric speaker to which an adhesive member (30a, 30b) having a thickness of 100 μm is attached, a second piezoelectric speaker to which an adhesive member (30a, 30b) having a thickness of 200 μm is attached, and a third piezoelectric speaker to which an adhesive member (30a, 30b) having a thickness of 300 μm is attached. At this time, the total attachment area of ​​the adhesive member (30a, 30b) attached to the first piezoelectric speaker, the total attachment area of ​​the adhesive member (30a, 30b) attached to the second piezoelectric speaker, and the total attachment area of ​​the adhesive member (30a, 30b) attached to the third piezoelectric speaker are assumed to be the same.

[0088] As a result of experiments on piezoelectric speakers (20) of three partial attachment methods as described above, it was found that the effect of increasing the sound pressure in the low-frequency range was greater when the thickness of the adhesive member (30a, 30b) in the partial attachment method was approximately 100 μm or more (more preferably, approximately 100 μm to 300 μm).

[0089] Figure 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.

[0090] The piezoelectric speaker according to the embodiment of the present invention was tested by attaching the adhesive member (30a, 30b) in a partial attachment manner, and the conventional piezoelectric speaker was tested by attaching the adhesive member in a full attachment manner (e.g., by attaching it so as to cover the entire surface of the diaphragm).

[0091] Even when the piezoelectric speaker according to the embodiment of the present invention and the conventional piezoelectric speaker are tested after being attached to a flat panel, as shown in FIG. 8, it was found that an increase in sound pressure in the low-frequency range may be possible when partially attached depending on the size of the flat panel and the size of the corresponding piezoelectric speaker (more specifically, the size of the diaphragm).

[0092] The above description is merely an illustrative illustration of the technical idea of ​​the present invention, and those skilled in the art will appreciate that various modifications and variations can be made without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the technical idea of ​​the present invention, and the scope of the technical idea of ​​the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within a scope equivalent thereto should be interpreted as being included in the scope of the rights of the present invention.

Claims

1. Includes a vibrating plate that outputs sound based on mechanical deformation occurring in a piezoelectric body; An adhesive member is attached to the above vibration plate, and the adhesive member is attached to a part of one surface of the above vibration plate. Piezoelectric speaker.

2. In paragraph 1, One side of the above adhesive member is attached to one side of the above vibration plate, The other side of the above adhesive member is attached to an adhesive member attachment target facing one side of the above vibration plate. Piezoelectric speaker.

3. In paragraph 2, The above adhesive member attachment target is, It is a curved panel, Piezoelectric speaker.

4. In paragraph 2, One side of the above diaphragm is, Flat, Piezoelectric speaker.

5. In paragraph 1, The above adhesive member is two in number, Piezoelectric speaker.

6. In paragraph 5, The above two adhesive members are, spaced apart from each other, Piezoelectric speaker.

7. In paragraph 5, The above two adhesive members are, The first adhesive member and the second adhesive member are attached to an area excluding the central portion of one side of the above-mentioned vibration plate. Piezoelectric speaker.

8. In paragraph 7, The central part of one side of the above vibration plate, A surface of the above-mentioned vibration plate is spaced apart from the object to which the adhesive member is attached. Piezoelectric speaker.

9. In paragraph 7, The above first adhesive member is attached to one side of one surface of the above vibration plate, The second adhesive member is attached to the other side of one side of the vibration plate. Piezoelectric speaker.

10. In paragraph 1, The above adhesive member is three or more, Piezoelectric speaker.

11. In paragraph 10, The above three or more adhesive members are, spaced apart from each other, Piezoelectric speaker.

12. In paragraph 10, The above three or more adhesive members are, Attached to an area excluding the central portion of one side of the above-mentioned vibration plate, Piezoelectric speaker.

13. In paragraph 12, The central part of one side of the above vibration plate, A surface of the above-mentioned vibration plate is spaced apart from the object to which the adhesive member is attached. Piezoelectric speaker.

14. In paragraph 1, The area to which the above adhesive member is attached is: 17% to 80% of the total area of ​​one side of the above vibration plate, Piezoelectric speaker.

15. In paragraph 1, The thickness of the above adhesive member is 100 μm to 300 μm, Piezoelectric speaker.

16. In paragraph 1, The above adhesive material is a double-sided tape. Piezoelectric speaker.

Images