Vibration driving apparatus

Abstract

A vibration driving apparatus includes a vibration member, and a vibration apparatus disposed at a rear surface of the vibration member and vibrating the vibration member according to a driving signal. The drive signal is an alternating current (AC) signal of 0 V or more.

Description

[0001] Cross - reference to related applications

[0002] This application claims the benefit of Korean Patent Application No. 10 - 2023 - 0189984, filed in Korea on December 22, 2023, the entire contents of which are incorporated herein by reference. Technical field

[0003] The present disclosure relates to a vibration - driving device. Background art

[0004] Recently, the demand for thinner electronic devices is increasing. In speakers applied to electronic devices, due to the demand for thinner devices, instead of voice coils, piezoelectric devices that can be implemented with a thin thickness are attracting wide attention.

[0005] A speaker or a vibration device including a piezoelectric device may be provided with driving power or a driving signal through a signal cable and may be driven or may vibrate. Summary of the invention

[0006] The inventors have recognized the following problems that occur when the developed piezoelectric devices are actually applied.

[0007] Piezoelectric devices include piezoelectric materials. Pb(Zr,Ti)O3 (PZT) - based materials have high piezoelectric characteristics and thus are used as piezoelectric materials. However, lead (Pb) is a material with strong toxicity and high volatility during the sintering process, thus causing serious environmental pollution.

[0008] Therefore, due to the problem of environmental pollution caused by PZT piezoelectric materials that occupy most of the piezoelectric materials, it is necessary to develop a lead - free piezoelectric material. Compared with PZT piezoelectric materials, lead - free piezoelectric materials have low piezoelectric characteristics, so high piezoelectric characteristics are required.

[0009] One aspect of the present disclosure aims to provide a piezoelectric material composition that may not contain lead and may have high piezoelectric characteristics.

[0010] One aspect of the present disclosure may drive a vibration device by using a monopole method and may thus provide a vibration - driving device having high piezoelectric characteristics and capable of achieving self - polarization of piezoelectric characteristics.

[0011] Additional features, advantages, and aspects of the present disclosure are partly set forth in the present disclosure, and will also be apparent from the present disclosure content, or may be learned through the practice of the inventive concepts provided herein. Other features, advantages, and aspects of the present disclosure may be realized and obtained through the present disclosure content or derivations from the present disclosure, as well as the structures specifically pointed out in the claims of the present disclosure and the accompanying drawings.

[0012] To achieve these and other advantages and aspects of the present disclosure, as embodied and generally described herein, in one or more aspects, a vibration driving device includes: a vibration member; and a vibration device disposed at a rear surface of the vibration member and configured to vibrate the vibration member according to a driving signal. The driving signal is an alternating current (AC) signal of 0 V or more.

[0013] According to one aspect of the present disclosure, a vibration driving device that does not contain lead (Pb) and has high piezoelectric characteristics can be provided.

[0014] According to one aspect of the present disclosure, since the piezoelectric material composition does not contain Pb, production-limiting materials can be reduced and substitution of harmful materials can be implemented. Therefore, an environmentally friendly piezoelectric material composition can be provided.

[0015] According to one aspect of the present disclosure, a piezoelectric device can be driven by a monopole method. Therefore, a vibration driving device capable of achieving self-polarization of piezoelectric characteristics can be provided.

[0016] By studying the following drawings and detailed descriptions, other systems, methods, features, and advantages will be apparent or will become apparent to those skilled in the art. All such additional systems, methods, features, and advantages are intended to be included in this specification, within the scope of the present disclosure, and protected by the appended claims. Nothing in this section should be construed as a limitation on these claims. Further aspects and advantages are discussed in connection with the aspects of the present disclosure below.

[0017] It should be understood that the foregoing description and the following description of the present disclosure are both exemplary and explanatory and are intended to provide further explanation of the claimed disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings are included to provide a further understanding of the present disclosure and are incorporated into and constitute a part of this disclosure, showing aspects and embodiments of the present disclosure and, together with the description, are used to explain the principles of the present disclosure. In the drawings:

[0019] Figure 1 is a diagram showing a vibration device according to one aspect of the present disclosure;

[0020] Figure 2 is a cross-sectional view taken along line A-A' shown in Figure 1 ;

[0021] Figure 3 is a cross-sectional view taken along line B-B' shown in Figure 1 ;

[0022] Figure 4 is a diagram showing a driving circuit according to an aspect of the present disclosure;

[0023] Figure 5 is a diagram showing a manufacturing method of a vibration device according to an aspect of the present disclosure;

[0024] Figure 6 is a diagram showing a graph of the electric field and polarization of a vibration device according to an aspect of the present disclosure;

[0025] Figures 7A to 7D is a diagram showing the bipolar driving reliability of a vibration device with respect to temperature according to an experimental example of the present disclosure;

[0026] Figure 8A and Figure 8B is a diagram showing the sound pressure level of a vibration device with respect to frequency according to an experimental example of the present disclosure;

[0027] Figures 9A to 9C is a diagram showing the sound pressure level of a vibration device with respect to frequency according to an aspect of the present disclosure;

[0028] Figure 10A and Figure 10B is a diagram showing the sound pressure level in the full frequency range of a vibration device according to an aspect of the present disclosure;

[0029] Figure 11A and Figure 11B is a diagram showing the sound pressure level of a piezoelectric device with respect to driving time according to an aspect of the present disclosure;

[0030] Figure 12 is a diagram showing an automotive audio device according to an aspect of the present disclosure;

[0031] Figure 13 is a perspective view of a display device according to an aspect of the present disclosure;

[0032] Figure 14 is along according to an aspect of the present disclosure Figure 13 a cross-sectional view taken along line I-I' shown in Detailed Description

[0033] Now, refer in detail to aspects of the present disclosure, examples of which may be shown in the accompanying drawings. In the following description, when a detailed description of a well-known method, function, structure, or configuration may unnecessarily obscure aspects of the present disclosure, for the sake of brevity, the detailed description of such well-known function or configuration may be omitted. In addition, for the sake of brevity, its repeated description may be omitted. The progress of the described processing steps and / or operations is a non-limiting example.

[0034] The order of steps and / or operations is not limited to the order described herein and may be changed to occur in an order different from that described herein, except for steps and / or operations that must occur in a particular order. In one or more examples, two consecutive operations may be performed substantially simultaneously, or the two operations may be performed in the reverse order or a different order depending on the functions or operations involved.

[0035] Unless otherwise specified, the same reference numerals may refer to the same elements throughout, even if shown in different figures. Unless otherwise specified, throughout the specification and the figures, the same reference numerals may be used to refer to the same or substantially the same elements. In one or more aspects, unless otherwise specified, the same elements (or elements with the same name) in different figures may have the same or substantially the same functions and characteristics. The names of the various elements used in the following description are chosen for convenience only and may therefore be different from the names used in actual products.

[0036] Aspects described with reference to the figures illustrate the advantages and features of the present disclosure and the methods of achieving them. However, the present disclosure may be implemented in different forms and should not be construed as limited to the example aspects set forth herein. On the contrary, these example aspects are examples, and providing these example aspects enables the present disclosure to be thorough and complete, to assist those skilled in the art in understanding the inventive concept without limiting the scope of the present disclosure.

[0037] The shapes, dimensions (e.g., size, length, width, height, thickness, position, radius, diameter, and area), ratios, rates, angles, quantities, number of elements, etc., disclosed herein, including those shown in the figures, are merely examples, and thus, the present disclosure is not limited to the details shown. Any implementation described herein as an "example" is not necessarily to be construed as preferred or superior to other implementations. However, it should be noted that the relative dimensions of the components shown in the figures are part of the present disclosure.

[0038] When terms such as "comprising," "having," "including," "containing," "constituting," "made of," "formed from," etc. are used with respect to one or more elements (e.g., layer, film, region, component, part, member, component, region, zone, portion, step, operation, etc.), one or more other elements may be added, unless a term such as "only" is used. The terms used in the present disclosure are only for describing example aspects and are not intended to limit the scope of the present disclosure. Singular forms of terms may include plural forms unless the context clearly indicates otherwise.

[0039] Unless otherwise specified, the term "exemplary" is used to mean serving as an example or illustration. An aspect is an example aspect. "Embodiment", "aspect", "example", etc. should not be construed as being preferred or advantageous over other implementations. Unless otherwise specified, an aspect, an example, an example aspect, etc. may refer to one or more aspects, one or more examples, one or more example aspects, etc. In addition, the term "may" encompasses all meanings and scopes of the term "can".

[0040] In one or more aspects, unless otherwise explicitly specified, an element, a feature, or the corresponding information (e.g., level, range, dimension, size, etc.) is construed to include a range of errors or tolerances, even if no explicit description of such a range of errors or tolerances is provided. The range of errors or tolerances may be caused by various factors (e.g., process factors, internal or external influences, noise, etc.). When interpreting a numerical value, unless otherwise explicitly specified, the value is construed to include the range of errors.

[0041] When describing positional relationships, in cases where the positional relationship between two components (e.g., layer, film, region, component, part, etc.) is described using, for example, "on", "above", "at the top of", "over", "under", "above", "below", "beneath", "near", "close to", "adjacent to", "beside", "in the vicinity of", "on one side or on a side of", etc., unless more restrictive terms such as "immediately (immediately)", "directly (directly)", or "proximate (proximately)" are used, one or more other components may be located between the two components. For example, when a structure is described as being positioned relative to another structure as follows: "on", "above", "at the top of", "over", "under", "above", "below", "beneath", "near", "close to", "adjacent to", "beside", "in the vicinity of", "on one side or on a side of", etc., such a description should be construed to include cases where the structures are in contact with each other and cases where one or more additional structures are arranged or inserted therebetween. In addition, terms such as "front", "rear", "back", "left", "right", "top", "bottom", "down", "up", "upper", "lower", "on", "off", "column", "row", "vertical", "horizontal", etc. refer to an arbitrary reference system.

[0042] Spatial relative terms such as "below", "beneath", "under", "underneath", "above", etc. may be used to describe the correlation between various elements (e.g., layers, films, regions, components, parts, etc.) shown in the drawings. The spatial relative terms should be understood to include terms for different orientations of the elements in use or operation in addition to the orientation shown in the drawings. For example, if the elements shown in the drawings are flipped, the element described as "below" or "beneath" other elements will be oriented "above" the other elements. Thus, the term "below" as an exemplary term may include all directions of "above" and "below". Similarly, the exemplary terms "above" or "upper" may include both directions of "above" and "below".

[0043] When describing temporal relationships, when the time sequence is described as, for example, "after", "subsequently", "next", "before", "previously", "in front of", etc., discontinuous or non-sequential cases may be included, and thus, one or more other events may occur therebetween, unless more restrictive terms such as "just", "immediately", or "directly" are used.

[0044] Terms such as "below", "lower", "above", "upper", etc. may be used to describe the relationship between the elements shown in the drawings. It should be understood that these terms are spatially relative and are based on the orientation shown in the drawings.

[0045] It should be understood that although terms such as "first", "second", etc. may be used herein to describe various elements (e.g., layers, films, regions, components, parts, members, components, regions, areas, parts, steps, operations, etc.), these elements should not be limited by these terms, e.g., any specific order, sequence, priority order, or quantity of the elements. These terms are only used to distinguish one element from another. For example, without departing from the scope of the present disclosure, the first element may be referred to as the second element, and similarly, the second element may be referred to as the first element. In addition, without departing from the scope of the present disclosure, the first element, the second element, etc. may be arbitrarily named according to the convenience of those skilled in the art. For the sake of clarity, the function or structure of these elements (e.g., the first element, the second element, etc.) is not limited by the ordinal number or name in front of the element. In addition, the first element may include one or more first elements. Similarly, the second element, etc. may include one or more second elements, etc.

[0046] When describing the elements of the present disclosure, terms such as "first", "second", "A", "B", "(a)", "(b)", etc. may be used. These terms are intended to identify the corresponding elements from other elements, and these terms are not used to define the essence, basis, order, sequence, or quantity of the elements.

[0047] For a description of an element (e.g., a layer, film, region, component, part, etc.) as being "connected", "coupled", "attached", "adhered", etc. to another element, unless otherwise specified, the element can not only be directly connected, coupled, attached, adhered, etc. to the other element, but also be indirectly connected, coupled, attached, adhered, etc. to the other element by disposing or inserting one or more intervening elements between the elements.

[0048] For a description of an element (e.g., a layer, film, region, component, part, etc.) as being "in contact with", "overlapping", etc. with another element, unless otherwise specified, the element can not only be directly in contact with, overlapping, etc. with the other element, but also be indirectly in contact with, overlapping, etc. with the other element by disposing or inserting one or more intervening elements between the elements.

[0049] Phrases such as an element (e.g., a layer, film, region, component, part, etc.) being "disposed in another element", "arranged on another element", "connected to another element", "coupled to another element", etc. can be understood to mean, for example, that at least a portion of the element is disposed in at least a portion of the other element, arranged on at least a portion of the other element, connected to at least a portion of the other element, coupled to at least a portion of the other element, etc., or that the whole of the element is disposed in the other element, arranged on the other element, connected to the other element, coupled to the other element, etc. Phrases such as an element (e.g., a layer, film, region, component, part, etc.) being "in contact with", "overlapping", etc. with another element can be understood to mean, for example, that at least a portion of the element is in contact with, overlapping, etc. with at least a portion of the other element, or that the whole of the element is in contact with at least a portion of the other element, or that at least a portion of the element is in contact with the whole of the other element.

[0050] Terms such as "line" or "direction" should not be interpreted solely based on the geometric relationship of the corresponding lines or directions being parallel or perpendicular to each other. Such terms can refer to lines or directions in which the components in the present disclosure can have a broader directivity within the scope of functional operation. For example, terms such as "first direction", "second direction", etc., which are, for example, directions parallel or perpendicular to the "x-axis", "y-axis", or "z-axis", should not be interpreted solely based on the geometric relationship of the respective directions being parallel or perpendicular to each other, and can refer to directions in which the components in the present disclosure can have a broader directivity within the scope of functional operation.

[0051] The term "at least one" shall be understood to include any and all combinations of one or more of the associated listed items. For example, each of the phrases "at least one of the first item, the second item, or the third item" and "at least one of the first item, the second item, and the third item" can represent (i) a combination of items provided by one or more of the first item, the second item, and the third item, or (ii) only one of the first item, the second item, and the third item.

[0052] The expression of the first element, the second element "and / or" the third element shall be understood to include one of the first element, the second element, and the third element, as well as any and all combinations of the first element, the second element, and the third element. By way of example, A, B, and / or C includes only A; only B; only C; any one of A, B, and C (e.g., A, B, or C); some combinations of A, B, and C (e.g., A and B; A and C; or B and C); and all of A, B, and C. In addition, the expression "A / B" can be understood as A and / or B. For example, the expression "A / B" can refer to only A; only B; A or B; or A and B.

[0053] In one or more aspects, unless otherwise specified, the terms "between" and "among" can be used interchangeably simply for convenience. For example, the expression "between a plurality of elements" can be understood as among a plurality of elements. In another example, the expression "among a plurality of elements" can be understood as between a plurality of elements. In one or more examples, the number of elements can be two. In one or more examples, the number of elements can be more than two. Further, when an element (e.g., a layer, a film, a region, a component, a part, etc.) is referred to as "between at least two elements", the element can be the only element between the at least two elements, or there can also be one or more intervening elements.

[0054] In one or more aspects, unless otherwise specified, the phrases "each other" and "one another" can be used interchangeably simply for convenience. For example, an expression "different from each other" can be understood as different from one another. In another example, an expression "different from one another" can be understood as different from each other. In one or more examples, the number of elements involved in the foregoing expressions can be two. In one or more examples, the number of elements involved in the foregoing expressions can be more than two.

[0055] In one or more aspects, unless otherwise specified, the phrases "one or more of which" and "one or more of" can be used interchangeably simply for convenience.

[0056] The term "or" means "inclusive or" rather than "exclusive or". For example, unless otherwise stated or the context clearly indicates, the statement "x uses a or b" means any one of the natural inclusive arrangements. For example, "a or b" can mean "a", "b", or "a and b". For example, "a, b or c" can mean "a", "b", "c", "a and b", "b and c", "a and c", or "a, b and c".

[0057] The features of the various aspects of the present disclosure can be partially or fully combined or combined with each other, can be technically interrelated, and can be operated, linked or driven together in various ways. The various aspects of the present disclosure can be implemented or executed independently of each other, or can be implemented or executed together in a mutually dependent or related relationship. In one or more aspects, the components of each device according to the various aspects of the present disclosure can be operably combined and configured.

[0058] Unless otherwise defined, the terms (including technical terms and scientific terms) used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the example aspects belong. It should be further understood that terms, such as those defined in a common dictionary, should be interpreted as having a meaning consistent with, for example, their meaning in the context of the relevant field, and should not be interpreted in an idealized or overly formal sense unless explicitly defined otherwise herein.

[0059] The terms used herein are selected as general terms in the relevant technical field. However, depending on the development and / or changes of the technology, conventions, preferences of those skilled in the art, etc., there may be other terms. Therefore, the terms used herein should not be construed as limiting the technical concept, but should be understood as examples of terms used to describe the example aspects.

[0060] In addition, in specific cases, the terms can be arbitrarily selected by the applicant, and in such cases, their detailed meanings are described herein. Therefore, the terms used herein should be understood not only based on the term names, but also based on the meanings and contents of the terms.

[0061] In the following description, various example aspects of the present disclosure are described in detail with reference to the accompanying drawings. For the reference numerals of the elements of each drawing, the same elements may be shown in other drawings, and unless otherwise stated, the same reference numerals may refer to the same elements. The same or similar elements may be represented by the same reference numerals even if they are shown in different drawings. In addition, for ease of description, the proportions, dimensions, sizes and thicknesses of each of the elements shown in the drawings may be different from the actual proportions, dimensions, sizes and thicknesses, and therefore, the aspects of the present disclosure are not limited to the proportions, dimensions, sizes and thicknesses shown in the drawings.

[0062] To solve such problems, the inventors have developed a vibration drive device that achieves vibration by using a BT-based piezoelectric material as a vibration layer and applying an alternating current (AC) signal of more than 0 V. The BT-based piezoelectric material may be a piezoelectric material containing BiTiO3.

[0063] Figure 1 FIG. 20 is a diagram showing a vibration device 20 according to an aspect of the present disclosure. Figure 2 is according to an aspect of the present disclosure along Figure 1 The cross-sectional view taken along line A-A' shown in FIG. Figure 3 is according to an aspect of the present disclosure along Figure 1 The cross-sectional view taken along line B-B' shown in FIG.

[0064] Referring to Figures 1 to 3 , the vibration device 20 according to an aspect of the present disclosure may include a vibration generating unit 10.

[0065] The vibration generating unit 10 may include at least one or more vibration parts. For example, the vibration generating unit 10 according to an exemplary aspect of the present disclosure may have a single-layer structure and may include one vibration part. For example, the vibration generating unit 10 may be a piezoelectric device, a vibration device, or a vibration part, but the aspects of the present disclosure are not limited thereto.

[0066] The vibration generating unit 10 may include a piezoelectric device or a piezoelectric material (or electroactive material) having a piezoelectric effect. For example, the vibration generating unit 10 may be a piezoelectric device. For example, the piezoelectric material (or piezoelectric device) may have such a property that by applying pressure or distortion to the crystal structure by an external force, a potential difference is generated due to dielectric polarization caused by a change in the relative positions of positive (+) ions and negative (-) ions, and vibration is generated based on the electric field of the voltage applied thereto.

[0067] The vibration generating unit 10 may include a vibration layer 11, a first electrode layer 13, and a second electrode layer 15.

[0068] The vibration layer 11 may be disposed between the first electrode layer 13 and the second electrode layer 15. The vibration layer 11 may contain a piezoelectric material (or electroactive material) having a piezoelectric effect. The vibration layer 11 may contain a ceramic material for implementing relatively high vibration, or may contain a piezoelectric ceramic having a perovskite crystal structure. For example, the vibration layer 11 may be a piezoelectric device layer, a piezoelectric material layer, a piezoelectric ceramic layer, a vibration layer, or a displacement layer, but the aspects of the present disclosure are not limited thereto.

[0069] The vibration layer 11 according to one aspect of the present disclosure may include a BT-based piezoelectric material that does not contain lead (Pb). For example, the vibration layer 11 according to one aspect of the present disclosure may contain a BT-based piezoelectric material represented by Formula 1 below. The BT-based piezoelectric material may contain barium (Ba), titanium (Ti), and zirconium (Zr).

[0070] [Formula 1]

[0071] aBa(Ti 1-y ,Zr y )O 3-b (Ba 1-x ,Ca x )TiO3 + c mol% A

[0072] For example, A may be TiO2, CuO, KF, FeO3, or NiO, 0.40 ≤ a ≤ 0.60, 0.40 ≤ b ≤ 0.60, 0.00 ≤ c ≤ 1.00, 0.05 ≤ x ≤ 0.30, 0.10 ≤ y ≤ 0.20.

[0073] The first electrode layer 13 may be disposed at the first surface (or lower surface) of the vibration layer 11. The first electrode layer 13 may have the same size as the vibration layer 11, or may have a size smaller than that of the vibration layer 11. For example, the first electrode layer 13 may include a single electrode shape. For example, the first electrode layer 13 may have a square shape. For example, the end (or side surface or side) of the first electrode layer 13 may be spaced apart from the end (or side surface or side) of the vibration layer 11, and thus, an electrical connection (or short circuit) between the first electrode layer 13 and the second electrode layer 15 can be prevented.

[0074] The second electrode layer 15 may be disposed at the second surface (or upper surface) of the vibration layer 11 that is different from or opposite to the first side. The second electrode layer 15 may have the same size as the vibration layer 11, or may have a size smaller than that of the vibration layer 11. For example, the second electrode layer 15 may include a single electrode shape. For example, the second electrode layer 15 may have a square shape. For example, the end (or side surface or side) of the second electrode layer 15 may be spaced apart from the end (or side surface or side) of the vibration layer 11, and thus, an electrical connection (or short circuit) between the second electrode layer 15 and the first electrode layer 13 can be prevented.

[0075] One or more of the first electrode layer 13 and the second electrode layer 15 according to an exemplary aspect of the present disclosure may include a transparent conductive material, a translucent conductive material, or an opaque conductive material. For example, the transparent conductive material or the translucent conductive material may include one or more of indium tin oxide (ITO) or indium zinc oxide (IZO), but the aspects of the present disclosure are not limited thereto. The opaque conductive material may include one or more of gold (Au), silver (Ag), platinum (Pt), palladium (Pd), molybdenum (Mo), magnesium (Mg), carbon, or a frit containing silver (Ag), or an alloy thereof, but the aspects of the present disclosure are not limited thereto. For example, the carbon may be a carbon material including carbon black, Ketjen black, carbon nanotubes, and graphite, but the aspects of the present disclosure are not limited thereto.

[0076] According to another aspect of the present disclosure, each of the first electrode layer 13 and the second electrode layer 15 may include silver (Ag) having a low resistance to enhance the electrical characteristics and / or vibration characteristics of the vibration layer 11.

[0077] In the first electrode layer 13 and the second electrode layer 15 including a frit containing silver (Ag), the content of the frit may be about 1 wt% or more to about 12 wt% or less, but the aspects of the present disclosure are not limited thereto. The frit may include a material based on PbO or Bi2O3, but the aspects of the present disclosure are not limited thereto.

[0078] The vibration layer 11 may be polarized (or polarised) by a certain voltage applied to the first electrode layer 13 and the second electrode layer 15 in a certain temperature atmosphere or in a temperature atmosphere changing from a high temperature to room temperature, but the aspects of the present disclosure are not limited thereto.

[0079] According to an aspect of the present disclosure, the vibration layer 11 may alternately repeat contraction and / or expansion based on the inverse piezoelectric effect of a sound signal (or voice signal) externally applied to the first electrode layer 13 and the second electrode layer 15, and thus, may vibrate. For example, the vibration layer 11 may vibrate based on the vertical vibration and the horizontal vibration generated by the first electrode layer 13 and the second electrode layer 15. The displacement (or vibration or drive) of the vibration member may be increased based on the horizontal contraction and / or expansion of the vibration layer 11, and thus, the vibration of the vibration device may be further enhanced.

[0080] The vibration layer 11 according to one aspect of the present disclosure can be polarized by an AC signal of more than 0V. In this case, the peak voltage Vp of the AC signal can have the value of the coercive field Ec of the piezoelectric material. For example, the coercive field Ec of the piezoelectric material included in the vibration layer 11 according to one aspect of the present disclosure can have a value in the range of 1.8 kV / cm to 2.3 kV / cm. For example, the coercive field Ec of the piezoelectric material can represent that the voltage supplied to a 1 cm thickness of the vibration layer 11 is 1.8 kV to 2.3 kV.

[0081] According to one aspect of the present disclosure, the driving voltage V and the peak voltage Vp in bipolar driving and unipolar driving can be calculated by using the coercive field Ec. For example, bipolar driving can be a method of performing driving by alternately changing a positive (+) voltage and a negative (-) voltage. For example, unipolar driving can be a method of performing driving by alternately changing 0 and a positive (+) voltage.

[0082] According to one aspect of the present disclosure, the vibration layer 11 can have a thickness of 150 μm. For example, when the coercive field Ec of the piezoelectric material is 1.8 kV at a thickness of 1 cm, the driving voltage can be 27V. This can be calculated by using a proportional equation. Therefore, when the coercive field Ec of the piezoelectric material is 1.8 kV / cm, the driving voltage V in bipolar driving can be ±13.5V, and the driving voltage V in unipolar driving can be 27V. Therefore, when the coercive field Ec of the piezoelectric material is 1.8 kV / cm, the peak voltage Vp in bipolar driving can be 13.5Vp, and the peak voltage Vp in unipolar driving can be 27Vp. For example, when the coercive field Ec of the piezoelectric material is 2.3 kV at a thickness of 1 cm, the driving voltage can be 34.5V. When the coercive field Ec of the piezoelectric material is 2.3 kV / cm, the driving voltage V in bipolar driving can be ±17.25V, and the driving voltage V in unipolar driving can be 33.5V. Therefore, when the coercive field Ec of the piezoelectric material is 2.3 kV / cm, the peak voltage Vp in bipolar driving can be 17.25Vp, and the peak voltage Vp in unipolar driving can be 33.5Vp.

[0083] Therefore, the vibration device according to one aspect of the present disclosure can be driven by a unipolar driving method (i.e., an AC signal of more than 0V), and the peak voltage Vp can be 33.5Vp or more. Therefore, the vibration device according to one aspect of the present disclosure can be driven by a unipolar driving method (i.e., an AC signal of more than 0V), and the peak voltage Vp can have a value in the range of 40Vp to 60Vp.

[0084] According to one aspect of the present disclosure, in order to replace lead (Pb), a BT-based piezoelectric material as a lead-free material can be used as the vibration layer 11. The BT-based piezoelectric material can be advantageous for the manufacturing method and can have relatively high piezoelectric characteristics among lead-free piezoelectric materials. However, due to the low Curie temperature Tc and the coercive field Ec, polarization may be easily released in bipolar driving, resulting in a reduction in the reliability of the vibration device.

[0085] For example, in bipolar driving, when the driving voltage is lower than the coercive field Ec, only the piezoelectric effect may exist, and polarization may not be achieved. For example, in bipolar driving, when the driving voltage is higher than the coercive field Ec, polarization may be easily released based on the BT-based domain, resulting in a reduction in the reliability of the vibration device.

[0086] One aspect of the present disclosure can use a lead-free BT-based piezoelectric material as the vibration layer 11 in order to replace lead (Pb) and can drive the vibration device by using a unipolar driving method driven by an AC signal of 0 V or more. Therefore, one aspect of the present disclosure can drive the vibration device by using a unipolar driving method. Thus, even when the vibration device is driven at a voltage greater than or equal to the coercive field Ec, deterioration of the vibration device due to repeated driving can be prevented. Therefore, in one aspect of the present disclosure, the sound pressure level can be self-polarized in the driving of the vibration device based on the low Curie temperature Tc and the coercive field Ec, and the reliability of the vibration device can be enhanced.

[0087] In addition, one aspect of the present disclosure can drive the vibration device by using a unipolar driving method driven by an AC signal of 0 V or more, and can set the peak voltage Vp of the AC signal to a value greater than or equal to the coercive field Ec of the piezoelectric material. Therefore, depolarization of the polarization of the vibration device can be prevented, and the sound pressure level of the vibration device can be increased.

[0088] The vibration device 20 according to one aspect of the present disclosure may further include a first cover member 30 and a second cover member 50.

[0089] The first cover member 30 may be disposed at the first surface of the vibration generating unit 10. For example, the first cover member 30 may be configured to cover the lower portion of the vibration generating unit 10. For example, the first cover member 30 may be configured to cover the first electrode layer 13 of the vibration generating unit 10. Therefore, the first cover member 30 can protect the first surface of the vibration generating unit 10.

[0090] The second cover member 50 may be disposed at the second surface of the vibration generating unit 10. The second surface of the vibration generating unit 10 may be different from or opposite to the first surface of the vibration generating unit 10. For example, the second cover member 50 may be configured to cover the second electrode layer 15 disposed at the second surface of the vibration generating unit 10. Thus, the second cover member 50 may protect the second electrode layer 15 disposed at the second surface of the vibration generating unit 10. According to another aspect of the present disclosure, only one of the first cover member 30 and the second cover member 50 may be configured.

[0091] Each of the first cover member 30 and the second cover member 50 according to one aspect of the present disclosure may include one or more materials of plastic, fiber, cloth, paper, leather, rubber, and wood, but the aspects of the present disclosure are not limited thereto. For example, each of the first cover member 30 and the second cover member 50 may include the same material or different materials. For example, each of the first cover member 30 and the second cover member 50 made of a plastic material may be a polyimide film, a polyethylene terephthalate film, or a polyethylene naphthalate film, but the aspects of the present disclosure are not limited thereto.

[0092] According to another aspect of the present disclosure, one or more of the first cover member 30 and the second cover member 50 may include an adhesive member. For example, one or more of the first cover member 30 and the second cover member 50 may include an adhesive member that is bonded to or adhered to the vibration layer 11, and a protective member (or a laminated member) that covers or protects the adhesive member. For example, the adhesive member may include an electrically insulating material having adhesive properties and capable of compression and decompression. For example, the first cover member 30 may include an adhesive member that is bonded or adhered to the vibration layer 11, and a protective member (or a laminated member) that covers or protects the adhesive member.

[0093] The adhesive layer 40 may include a first adhesive layer 41 and a second adhesive layer 42. The first cover member 30 may be connected to or bonded to at least a part of the first electrode layer 13 or the first surface of the vibration generating unit 10 through the first adhesive layer 41. For example, the first cover member 30 may be connected to or bonded to at least a part of the first electrode layer 13 or the first surface of the vibration generating unit 10 through a film lamination process using the adhesive layer 40.

[0094] The second cover member 50 may be connected to or bonded to at least a part of the second electrode layer 15 or the second surface of the vibration generating unit 10 through the second adhesive layer 42. For example, the second cover member 50 may be connected to or bonded to at least a part of the second electrode layer 15 or the second surface of the vibration generating unit 10 through a film lamination process using the adhesive layer 40.

[0095] The adhesive layer 40 according to one aspect of the present disclosure may include an electrically insulating material having adhesive properties and capable of compression and decompression. For example, the adhesive layer 40 may include epoxy resin, acrylic resin, silicone resin, and urethane resin, but the aspects of the present disclosure are not limited thereto.

[0096] The vibration device 20 according to one aspect of the present disclosure may further include a signal cable 90.

[0097] The signal cable 90 may be implemented to be connected to the vibration generating unit 10 at one side or a part of the vibration generating unit 10. The signal cable 90 may be connected to the vibration generating unit 10 between the first cover member 30 and the second cover member 50.

[0098] An end portion (or a distal end portion) of the signal cable 90 may be disposed in or inserted (or received) into a part between a peripheral portion on one side of the first cover member 30 and a peripheral portion on one side of the second cover member 50. The peripheral portion on one side of the first cover member 30 and the peripheral portion on one side of the second cover member 50 may receive or vertically cover a part of the signal cable 90. Accordingly, the signal cable 90 may be provided integrally with the vibration generating unit 10. For example, the vibration device according to an exemplary aspect of the present disclosure may be a vibration device provided integrally with the signal cable 90. For example, the signal cable 90 may be configured as a flexible cable, a flexible printed circuit cable, a flexible flat cable, a single-sided flexible printed circuit, a single-sided flexible printed circuit board (PCB), a flexible multi-layer printed circuit, or a flexible multi-layer PCB, but the aspects of the present disclosure are not limited thereto.

[0099] The signal cable 90 according to one aspect of the present disclosure may include a base member 91 and a plurality of signal lines 92a and 92b. For example, the plurality of signal lines 92a and 92b may include a base member 91, a first signal line 92a, and a second signal line 92b.

[0100] The base member 91 may include a transparent or opaque plastic material. For example, the base member 91 may include one or more of synthetic resins, such as fluororesin, polyimide resin, polyurethane resin, polyester resin, polyethylene resin, and polypropylene resin, but the aspects of the present disclosure are not limited thereto. The base member 91 may be a base film or a base insulating film, but the aspects of the present disclosure are not limited thereto.

[0101] The base member 91 may have a certain width in the first direction X and may longitudinally extend in a second direction Y intersecting the first direction X.

[0102] Each of the first signal line 92a and the second signal line 92b may be disposed at or on the first surface of the base member 91 parallel to the second direction Y, and may be spaced apart or separated from each other in the first direction X. Each of the first signal line 92a and the second signal line 92b may be arranged in parallel at or on the first surface of the base member 91. For example, each of the first signal line 92a and the second signal line 92b may be realized in a linear shape by patterning a metal layer (or conductive layer) formed or deposited at or on the first surface of the base member 91.

[0103] The first signal line 92a may be disposed at the lower surface of the first electrode layer 13. The first electrode layer 13 may contact the first signal line 92a. The first electrode layer 13 may be electrically connected to the first signal line 92a.

[0104] The second signal line 92b may be disposed at the upper surface of the second electrode layer 15. The second electrode layer 15 may contact the second signal line 92b. The second electrode layer 15 may be electrically connected to the second signal line 92b.

[0105] The ends (or distal ends) of each of the first signal line 92a and the second signal line 92b may be separated from each other, and thus, may be bent or folded individually.

[0106] The end (or distal end) of the first signal line 92a may be electrically connected to at least a part of the first electrode layer 13 of the vibration generating unit 10 at one edge of the first cover member 30. For example, the end (or distal end) of the first signal line 92a may be electrically connected to at least a part of the first electrode layer 13 of the vibration generating unit 10. For example, the end (or distal end) of the first signal line 92a may be directly connected to or in direct contact with the first electrode layer 13 of the vibration generating unit 10. Thus, the first signal line 92a may supply a drive signal provided from the vibration drive circuit to the first electrode layer 13 of the vibration generating unit 10. For example, the drive signal may be an alternating current (AC) signal.

[0107] The end (or distal end) of the second signal line 92b can be electrically connected to at least a portion of the second electrode layer 15 of the vibration generating unit 10 at one edge of the second cover member 50. For example, the end (or distal end) of the second signal line 92b can be electrically connected to at least a portion of the second electrode layer 15 of the vibration generating unit 10. For example, the end (or distal end) of the second signal line 92b can be directly connected to the second electrode layer 15 of the vibration generating unit 10 or in direct contact with the second electrode layer 15 of the vibration generating unit 10. Accordingly, the second signal line 92b can supply a drive signal provided from the vibration drive circuit to the second electrode layer 15 of the vibration generating unit 10. For example, the drive signal can be provided to the first signal line 92a and the second signal line 92b.

[0108] In the vibration generating unit 10, the first electrode layer 13 can receive the drive signal through or by the first signal line 92a, and the second electrode layer 15 can receive the drive signal through or by the second signal line 92b. Accordingly, the vibration generating unit 10 can alternately repeat contraction and / or expansion based on the inverse piezoelectric effect generated in the vibration layer 11 by the drive signal, whereby it can vibrate (or shift or drive).

[0109] The signal cable 90 according to one aspect of the present disclosure can further include an insulating member 93.

[0110] The insulating member 93 can be disposed at the first surface of the base member 91 to cover each of the first signal line 92a and the second signal line 92b except for the end of the signal cable 90. The insulating member 93 can be a protective layer, a covering, a covering layer, a covering film, an insulating film, or a solder mask, but the aspects of the present disclosure are not limited thereto.

[0111] The signal cable 90 or the base member 91 can include a first extension portion 91a that supports the end of the first signal line 92a. The first extension portion 91a can extend in the second direction Y from the end of the base member 91 that covers the first signal line 92a disposed at the base member 91, and thus, can support the first signal line 92a. The first signal line 92a can be disposed on the lower surface (or bottom surface) of the first extension portion 91a so as to be directly connected to the vibration generating unit 10.

[0112] The signal cable 90 or the base member 91 can include a second extension portion 91b that separately supports the end of the second signal line 92b. The second extension portion 91b can extend in the second direction Y from the end of the base member 91, and thus, can support the second signal line 92b. The second signal line 92b can be disposed on the lower surface (or bottom surface) of the second extension portion 91b so as to be directly connected to the vibration generating unit 10.

[0113] The signal cable 90 may include a first extension portion 91a and a second extension portion 91b that support the ends of each of the first signal line 92a and the second signal line 92b that are separated from each other. For example, the first extension portion 91a and the second extension portion 91b may be separated from each other between a peripheral portion on one side of the first cover member 30 and a peripheral portion on one side of the second cover member 50. Accordingly, the ends (or distal ends) of the first signal line 92a and the second signal line 92b may be separated from each other, and thus, may be bent or folded individually.

[0114] According to another aspect of the present disclosure, each of the first extension portion 91a and the second extension portion 91b of the signal cable 90 may be omitted. For example, the first signal line 92a and the second signal line 92b may protrude or extend in a finger shape from a base member 91 of each of the first signal line 92a and the second signal line 92b, and may be electrically connected to or in contact with corresponding electrode layers 13 and 15 between a peripheral portion on one side of the first cover member 30 and a peripheral portion on one side of the second cover member 50, respectively. For example, the ends of each of the first signal line 92a and the second signal line 92b may be electrically connected to or in contact with the corresponding electrode layers 13 and 15 through double-sided tape, and thus, adhesion to the corresponding electrode layers 13 and 15 may be ensured.

[0115] The end (or distal end) of the signal cable 90 inserted (or accommodated) between the first cover member 30 and the second cover member 50 may be inserted (or accommodated) and fixed between the first cover member 30 and the second cover member 50 through a film lamination process using a first adhesive layer 41 formed in the first cover member 30 and a second adhesive layer 42 formed in the second cover member 50. Accordingly, the first signal line 92a may remain electrically connected to the first electrode layer 13 of the vibration generating unit 10, and the second signal line 92b may remain electrically connected to the second electrode layer 15 of the vibration generating unit 10. In addition, the end (or distal end) of the signal cable 90 may be inserted (or accommodated) and fixed between the first cover member 30 and the second cover member 50, and thus, connection defects between the vibration generating unit 10 and the signal cable 90 caused by movement of the signal cable 90 may be prevented.

[0116] In a vibration device according to an aspect of the present disclosure, the first signal line 92a and the second signal line 92b of the signal cable 90 may be connected to the electrode layers of the vibration generating unit 10 between the first cover member 30 and the second cover member 50, and thus, a welding process for electrical connection between the vibration generating unit 10 and the signal cable 90 may not be required, thereby simplifying the structure and the manufacturing process. In addition, according to an exemplary aspect of the present disclosure, the manufacturing process may be simplified, and thus, process optimization may be achieved by reducing production energy.

[0117] Figure 4A diagram showing a driving circuit according to an aspect of the present disclosure. Figure 4 Shows a connection to Figures 1 to 3 The driving circuit of the vibration device shown in

[0118] Referring to Figures 1 to 4 , an aspect of the present disclosure may further include a driving circuit 600 that provides a driving signal to the vibration device 20. The driving circuit 600 may be electrically connected to the vibration device 20 and may generate a driving signal based on a sound source to supply to the vibration device 20, and thus, may cause the vibration device 20 to vibrate or shift.

[0119] The driving circuit 600 according to the present disclosure may include an amplifier 601 connected to a vibration generating unit 10 that constitutes the vibration device 20. The amplifier 601 may generate an AC-type driving signal including a first vibration driving signal and a second vibration driving signal based on a sound source. The amplifier 601 may output an AC signal to the vibration generating unit 10. For example, the amplifier 601 according to an aspect of the present disclosure may apply an AC signal of 0 V or more to the vibration generating unit 10. For example, the amplifier 601 may include a first output terminal T11 that outputs a first vibration driving signal and a second output terminal T12 that outputs a second vibration driving signal.

[0120] In the amplifier 601, the first output terminal T11 may be electrically connected to the first electrode layer 13 of the vibration generating unit 10. The second output terminal T12 may be electrically connected to the second electrode layer 15 of the vibration generating unit 10. For example, the first output terminal T11 of the amplifier 601 may be electrically connected to the first electrode layer 13 of the vibration generating unit 10, and the second output terminal T12 of the amplifier 601 may be electrically connected to the second electrode layer 15 of the vibration generating unit 10. For example, the first vibration driving signal output from the first output terminal T11 of the amplifier 601 may be provided to the first electrode layer 13 through the first signal line 92a and the flexible signal cable 90 of the vibration generating unit 10. The second vibration driving signal output from the second output terminal T12 of the amplifier 601 may be provided to the second electrode layer 15 through the second signal line 92b and the flexible signal cable 90 of the vibration generating unit 10.

[0121] For example, when the first vibration driving signal output from the first output terminal T11 of the amplifier 601 is 0V, the second vibration driving signal output from the second output terminal T12 of the amplifier 601 can be the peak voltage Vp. For example, when the second vibration driving signal output from the second output terminal T12 of the amplifier 601 is 0V, the first vibration driving signal output from the first output terminal T11 of the amplifier 601 can be the peak voltage Vp. For example, the peak voltage Vp according to one aspect of the present disclosure may have a value greater than or equal to the coercive field Ec of the piezoelectric material. For example, the peak voltage Vp of the AC signal may have a value greater than or equal to the coercive field Ec of the piezoelectric material. For example, the coercive field Ec of the piezoelectric material included in the vibration layer 11 according to one aspect of the present disclosure may have a range of 1.8 kV / cm to 2.3 kV / cm. Therefore, the peak voltage Vp of the vibration layer 11 according to one aspect of the present disclosure may be 40Vp to 60Vp.

[0122] One aspect of the present disclosure may use a lead-free BT-based piezoelectric material as the vibration layer 11 to replace lead (Pb) and may drive the vibration device by using a single-pole driving method driven by an AC signal of 0V or more. Therefore, it is possible to prevent the driving reliability from being reduced due to the low Curie temperature Tc and the coercive field Ec. In addition, one aspect of the present disclosure may drive the vibration device by using a single-pole driving method driven by an AC signal of 0V or more, and may set the peak voltage Vp of the AC signal to a value greater than or equal to the coercive field Ec of the piezoelectric material. Therefore, it is possible to increase the sound pressure level of the vibration device and to achieve self-polarization of the sound pressure level.

[0123] Figure 5 is a diagram showing a method of manufacturing a vibration device according to one aspect of the present disclosure. This relates to a method of manufacturing the vibration device described above by the tape casting method. Figures 1 to 3 The tape casting method may be a method of molding and sintering materials with a ductile sheet.

[0124] Referring to Figure 5 , a method S100 of manufacturing a vibration device including a piezoelectric material composition according to one aspect of the present disclosure may include: a step S110 of weighing raw materials; a step S120 of mixing the weighed raw materials; a calcination and synthesis step S130 of synthesizing the mixed raw materials; a step S140 of grinding the synthesized matrix material; a step S150 of preparing a slurry; a step S160 of compacting the slurry; a step S170 of sintering the molded body to prepare a sintered body; and a step S180 of forming an external electrode on the sintered body.

[0125] For example, a method of manufacturing a piezoelectric material composition according to one or more aspects of the present disclosure may start with mixing raw materials having Formula 1. In the following description, conditions such as temperature, pressure, and time based on the manufacturing method of the piezoelectric material composition may be included, but aspects of the present disclosure are not limited thereto.

[0126] First, the step S110 of weighing the raw materials may be to weigh the raw materials according to a molar ratio to add an appropriate amount of solvent.

[0127] The piezoelectric material composition of a piezoelectric device according to one aspect of the present disclosure may be represented by the following Formula 1.

[0128] [Formula 1]

[0129] aBa(Ti 1-y ,Zr y )O 3-b (Ba 1-x ,Ca x )TiO3 + c mol% A

[0130] For example, A may be TiO2, CuO, KF, FeO3, or NiO, 0.40 ≤ a ≤ 0.60, 0.40 ≤ b ≤ 0.60, 0.00 < c ≤ 1.00, 0.05 ≤ x ≤ 0.30, 0.10 ≤ y ≤ 0.20.

[0131] The raw materials of the piezoelectric material composition satisfying Formula 1 may include barium zirconate (BaZrO3), calcium carbonate (CaCO3), barium carbonate (BaCO3), titanium oxide (TiO2), copper oxide (CuO), potassium fluoride (KF), iron oxide (Fe2O3), and nickel oxide. For example, the step S110 of weighing the raw materials may be a process of weighing the raw materials according to the molar ratio of the composition for synthesis, putting the weighed raw materials into a nylon jar, and adding an appropriate amount of solvent (for example, ethanol), but aspects of the present disclosure are not limited thereto.

[0132] The matrix material according to one aspect of the present disclosure may include Fe2O3. For example, Fe2O3 may be added at 1 mol% or less. For example, Fe2O3 may be added at 0.5 mol%. Therefore, according to one aspect of the present disclosure, Fe2O3 may be added, and thus, the sinterability of the piezoelectric material may be further improved.

[0133] Subsequently, in step S120 of mixing the raw materials, the weighed raw materials and ethanol can be mixed and ground by a ball mill process. The weighed raw materials and ethanol can be placed in a Nalgene bottle together with zirconia balls (e.g., yttria-stabilized zirconia (YSZ) balls) and ethanol, and can be ground. For example, the grinding can be wet grinding, but aspects of the present disclosure are not limited thereto. For example, the ball milling process can be performed for 12 hours to 36 hours within the range of 100 rpm to 150 rpm, but aspects of the present disclosure are not limited thereto.

[0134] An aspect of the present disclosure can further include a drying step of separating the powder mixed with the solvent after the mixing step. Here, the drying step can separate and discharge the ground raw materials from the balls, and then, the mixed raw materials can be placed in a dish and the mixed raw materials can be dried at a temperature of 90°C to 100°C. For example, the drying can be performed for 3 hours, but aspects of the present disclosure are not limited thereto. Thus, the ethanol mixed with the raw materials can be removed.

[0135] Subsequently, an aspect of the present disclosure can include step S130 of calcining the raw materials. Step S130 of calcining the raw materials can be a phase synthesis of the once-mixed raw materials. The phase synthesis step S130 can include a step of finely grinding the dried compound with a mortar after mixing is completed, and a step of performing heat treatment in an electric furnace after placing it in an alumina crucible. For example, the calcination temperature can be 1000°C to 1200°C and the holding time can be 3 hours to 6 hours, but aspects of the present disclosure are not limited thereto. For example, an aspect of the present disclosure can further include a step of cooling or naturally cooling to room temperature after calcination. Thus, in an aspect of the present disclosure, the carbonate of the raw materials can be removed, and the raw materials can react uniformly to form a uniform perovskite phase.

[0136] Subsequently, step S140 of grinding the matrix material after the calcination is completed can be to place the matrix material in a Nalgene bottle together with YSZ balls and a solvent (ethanol) and grind the matrix material by a ball milling process to form small particles, but aspects of the present disclosure are not limited thereto. The grinding process can be performed for 24 hours within the range of 100 rpm to 150 rpm, but aspects of the present disclosure are not limited thereto.

[0137] In addition, the grinding step can also include a drying step of separating the powder mixed with the solvent after the grinding step. Here, the drying step can separate and discharge the ground raw materials from the balls, and then, the ground matrix material can be placed in a dish and the ground matrix material can be dried at a temperature of 90°C to 100°C. For example, the drying can be performed for 3 hours, but aspects of the present disclosure are not limited thereto.

[0138] According to one aspect of the present disclosure, the step S140 of grinding the calcined matrix material may further include sieving or granulating the material.

[0139] The sieving or granulating step may be filtering the dry powder finely ground in a mortar through a 40-mesh sieve to produce a powder including particles having a certain size or smaller. The powder passing through the 40-mesh sieve may have a size of 400 μm or less, but the aspects of the present disclosure are not limited thereto. For example, the sieving step may be granulating the composition.

[0140] Subsequently, the step S150 of preparing the slurry may include performing primary slurry grinding on the matrix material, performing secondary slurry grinding on the matrix material, and performing tape casting on the matrix material.

[0141] The step S150 of preparing the slurry may add an appropriate amount of a dispersant and a solvent to the matrix material having the composition of Formula 1. For example, the solvent may include one or more of ethanol, methanol, isopropyl alcohol, methyl ethyl ketone (MEK), toluene, and distilled water, but the aspects of the present disclosure are not limited thereto. By adding an appropriate amount of a dispersant and a solvent to the matrix material, a slurry in which the matrix material is well dispersed in the solvent can be prepared. For example, the step of preparing the slurry may be prepared by performing a grinding step twice, but the aspects of the present disclosure are not limited to the number of grinding steps.

[0142] For example, primary slurry grinding of the prepared matrix material slurry may be performed by putting an appropriate amount of a solvent and a dispersant together with YSZ balls into a Nalgene bottle. Such a primary slurry grinding step may be dispersing the matrix powder. The primary slurry grinding may be ball milling, but the aspects of the present disclosure are not limited thereto. For example, the primary slurry grinding may be performed within a range of 100 rpm to 150 rpm for 12 hours to 72 hours, but the aspects of the present disclosure are not limited thereto. For example, the primary slurry grinding may be performed at 130 rpm for 12 hours, but the aspects of the present disclosure are not limited thereto. For example, the primary slurry grinding may be wet grinding, but the aspects of the present disclosure are not limited thereto.

[0143] For example, after the primary slurry grinding, secondary slurry grinding may be performed by further adding an appropriate amount of a binder and a plasticizer. The secondary slurry grinding may be mixing and dispersing the binder and the plasticizer in the primary slurry. The secondary slurry grinding may be ball milling, but the aspects of the present disclosure are not limited thereto. For example, the secondary slurry grinding may be performed within a range of 100 rpm to 150 rpm for 6 hours to 24 hours, but the aspects of the present disclosure are not limited thereto. For example, the secondary slurry grinding may be wet grinding, but the aspects of the present disclosure are not limited thereto.

[0144] One aspect of the present disclosure may further include an aging step and a degassing step of removing bubbles and gases after secondary slurry grinding.

[0145] The degassing step may be a step of adjusting the slurry to have an appropriate viscosity for the molding process and removing residual bubbles in the slurry during the following steps of molding the piezoelectric material. For example, the degassing step may be adjusted to have a viscosity of 1000 cPs (centipoise) to 3000 cPs, 1500 cPs to 2500 cPs, or 3000 cPs at room temperature by a vacuum stirrer, but the aspects of the present disclosure are not limited thereto. For example, the degassing step may be adjusted to have a viscosity of 1700 cPs (centipoise) to 2400 cPs, or 2000 cPs at room temperature by a vacuum stirrer, but the aspects of the present disclosure are not limited thereto. Accordingly, bubbles in the slurry can be removed, and the viscosity can be adjusted by volatilizing the solvent.

[0146] The aging step may be to adjust the temperature back to room temperature because the slurry is cooled when the solvent volatilizes during the degassing step. For example, in the aging step, stirring may be performed at a low speed of about 10 rpm for a short time by a stirrer, but the aspects of the present disclosure are not limited thereto. Accordingly, a piezoelectric material in the form of a slurry can be formed.

[0147] Subsequently, the step S160 of press-molding the slurry may be a tape casting step. For example, the tape casting step may be to tape-cast the slurry obtained by mixing the matrix material and the seed material prepared in the previous step by a tape casting device (or blade). For example, when tape casting is performed at a temperature of 90 °C or higher, since the evaporation rate of the solvent is high, the manufactured sheet may crack, or defects such as voids may occur. Accordingly, the temperature condition for each period of the tape casting device may be 30 °C to less than 90 °C. For example, the tape casting step may be a process of putting the degassed secondary slurry into a slurry chamber, passing it through a doctor blade (or comma blade) adjusted to a certain height at a certain speed (for example, a speed of 0.5 mm / min), and molding it into a green sheet (or molded sheet) via a temperature range. The temperature range may include ranges of 40 °C, 60 °C, and 80 °C, but the aspects of the present disclosure are not limited thereto.

[0148] In addition, an aspect of the present disclosure may further include a step S160 of forming an internal electrode. For example, the step of forming the internal electrode may be printing the electrode on a tape cast green sheet. For example, an internally patterned electrode for manufacturing a multi-layer ceramic application (MLCA: Multi-Layered Ceramic Application) may be printed by a screen printing method. For example, the MLCA may be a multi-layer vibration device. For example, the multi-layer vibration device may include a plurality of vibration devices stacked in sequence. Each of the plurality of vibration devices may include a vibration layer containing ceramics and electrode layers formed on each of the upper and lower surfaces of the vibration layer. For example, since each of the plurality of vibration devices is stacked in sequence, electrode layers may be provided on each of the lowermost surface and the uppermost surface of the multi-layer vibration device, and each of the plurality of electrode layers may be provided between two adjacent vibration layers of the plurality of vibration layers containing ceramics. For example, other electrode layers (or electrode layers provided between adjacent vibration layers) among the plurality of electrode layers except for the electrode layer provided on the uppermost surface and the electrode layer provided on the lowermost surface may be internally patterned electrodes formed by printing such as screen printing. As another example, in a single-layer ceramic application (SLCA: Single-Layered Ceramic Application), an internal electrode may not be required, and thus, the step of printing the internal electrode may be omitted. For example, the SLCA may include one vibration device. For example, one vibration device may include a vibration layer containing ceramics and electrode layers formed on each of the upper and lower surfaces of the vibration layer. For example, in a single-layer ceramic application (SLCA), an internal electrode may not be required, and thus, the step of printing the internal electrode may be omitted. For example, in the SLCA, electrode layers may not be provided between the vibration layers, and thus, the step of printing the internal electrode may be omitted.

[0149] The tape cast piezoelectric material (or sheet) may be stacked (or laminated), and then, it may be pressed at a pressure of 2500 psi / cm 2 to 4000 psi / cm 2 for 10 minutes to 30 minutes at 55°C to 75°C. For example, the tape cast piezoelectric material (or sheet) may be stacked, and then, it may be pressed at a pressure of 3000 psi / cm 2 for 10 minutes at 60°C. For example, the lamination (or stacking) may be stacking the prepared green sheets and the green sheets may be stacked at a pressure of 100 MPa / cm 2 but the aspects of the present disclosure are not limited thereto.

[0150] The steps of molding a piezoelectric material by tape casting can be performed by warm isostatic pressing (WIP). In a piezoelectric material composition according to an aspect of the present disclosure, WIP can be performed in the case of preparing a molded body based on stacking and laminating (e.g., tape casting). For example, the stacked piezoelectric materials can be vacuum-packed by WIP, and then, can be placed in water at 60 °C to 65 °C and can be held and pressed at a pressure of 3000 psi / cm 2 or more for 10 minutes, but the aspects of the present disclosure are not limited thereto. WIP can be hot isostatic pressing, but the aspects of the present disclosure are not limited thereto.

[0151] The step S160 of pressing the slurry into a mold may further include a debinding step. The debinding step may be to remove a solvent or an organic material. The debinding step may be to burn an organic solvent (e.g., a binder, a plasticizer, or a dispersant) before sintering the stacked molded sheets completed by WIP. The debinding step may hold the molded body in a furnace at a temperature in the range of 250 °C to 600 °C for 24 hours to 72 hours, and then, the molded body can be cooled to room temperature.

[0152] Subsequently, the step S170 of sintering the molded body to prepare a sintered body may involve placing the molded body in a furnace, holding the molded body in the furnace at a temperature in the range of 250 °C to 600 °C for 24 hours to 72 hours, and then, cooling the molded body to room temperature, but the aspects of the present disclosure are not limited thereto.

[0153] Subsequently, the step S180 of forming electrodes in the sintered body may form electrodes on a first surface of the sintered body of the piezoelectric material prepared in the previous step and a second surface of the sintered body of the piezoelectric material opposite to the first surface. For example, the second surface of the sintered body of the piezoelectric material may be different from the first surface or may be opposite to the first surface. For example, the electrodes may contain a metal, for example, may be formed by coating a metal (e.g., silver (Ag)), but the aspects of the present disclosure are not limited thereto, and electrodes other than general electrodes may be used. For example, the step S170 of forming electrodes in the sintered body may print electrodes in the sintered body by screen printing, but the aspects of the present disclosure are not limited thereto. For example, the step S170 of forming electrodes in the sintered body may include forming electrodes in the sintered body, raising the temperature from 400 °C to 600 °C at a temperature rising rate of 5 °C / min, then holding the sintered body at 600 °C for 10 minutes to 30 minutes, naturally cooling the sintered body at room temperature, and applying an electric field of 3 kV / mm at a temperature of 20 °C to 40 °C for about 20 minutes to perform a polarization (or poling) process on the electrodes, but the aspects of the present disclosure are not limited thereto.

[0154] Therefore, a manufacturing method of a vibration device according to an aspect of the present disclosure that does not contain lead (Pb) and has high piezoelectric characteristics can be provided.

[0155] According to one aspect of the present disclosure, since the piezoelectric material composition does not contain Pb, production-limiting materials can be reduced and replacement of harmful materials can be implemented, and thus, an environmentally friendly piezoelectric material composition can be provided.

[0156] Figure 6 is a graph showing the electric field and polarization of a vibration device according to one aspect of the present disclosure. This relates to the hysteresis loop of the polarization of a piezoelectric material according to one aspect of the present disclosure with respect to the electric field.

[0157] Referring to Figure 6 , the coercive field Ec of the vibration layer included in the vibration device according to one aspect of the present disclosure may have a value in the range of 1.8 kV / cm to 2.3 kV / cm.

[0158] In order to compare the vibration characteristics of bipolar driving with those of unipolar driving, the inventors calculated the voltage when the thickness of the vibration layer was 150 μm based on a proportional equation. For example, referring to Figure 6 , the voltage applied to the vibration layer when the thickness of the vibration layer was 150 μm was calculated to be in the range of approximately 27.0 V to 34.5 V. Therefore, when the coercive field Ec has a value in the range of 1.8 kV / cm to 2.3 kV / cm, the peak voltage Vp of bipolar driving is calculated to be in the range of 13.5 Vp to 17.25 Vp.

[0159] Table 1 below shows the vibration accelerations of the vibration device according to one aspect of the present disclosure with respect to bipolar driving and unipolar driving. Table 1 shows the vibration accelerations of bipolar driving and unipolar driving including the piezoelectric material composition based on Equation 1 described above. In Table 1, the thickness of the vibration layer was fabricated to be 150 μm, and based on the coercive field Ec of the piezoelectric material described above, the peak voltage Vp of bipolar driving was set to 12 Vp, 20 Vp, and 30 Vp. In Table 1, based on the coercive field Ec of the piezoelectric material described above, the peak voltage Vp of unipolar driving was set to 24 Vp, 40 Vp, and 60 Vp. In Table 1, the vibration acceleration G Figures 1 to 3 and G b and G u each is a numerical value based on the vibration amplitude of each driving method. G b / G u represents the ratio of the vibration acceleration that occurs in bipolar driving to the vibration acceleration that occurs in unipolar driving.

[0160] [Table 1]

[0161]

[0162] Referring to Table 1, in a vibration device according to an aspect of the present disclosure, in bipolar driving, vibration accelerations of 0.41, 0.57, and 0.98 are shown at -12V / 12V, -20V / 20V, and -30V / 30V, respectively. Additionally, in a vibration device according to an aspect of the present disclosure, in unipolar driving, vibration accelerations of 0.44, 0.70, and 2.08 are shown at 0V / 24V, 0V / 40V, and 0V / 60V, respectively.

[0163] According to an aspect of the present disclosure, in unipolar driving and bipolar driving of a vibration device, the vibration acceleration increases as the driving voltage increases.

[0164] According to an aspect of the present disclosure, the vibration device shows that at a peak voltage above 40Vp, the vibration acceleration in unipolar driving is higher than that in bipolar driving.

[0165] According to an aspect of the present disclosure, the vibration device shows that when the value of the peak voltage Vp (e.g., 40V and 60V) is greater than or equal to the coercive field Ec of the piezoelectric material, the vibration acceleration is higher than the case where the value of the peak voltage Vp (e.g., 20V) is less than or equal to the coercive field Ec of the piezoelectric material.

[0166] Therefore, an aspect of the present disclosure can use a lead-free BT-based piezoelectric material as the vibration layer 11 to replace lead (Pb) and can drive the vibration device by using a unipolar driving method driven by an AC signal above 0V. Therefore, a reduction in driving reliability due to a low Curie temperature Tc and coercive field Ec can be prevented.

[0167] Furthermore, an aspect of the present disclosure can drive the vibration device by using a unipolar driving method driven by an AC signal above 0V, and can set the peak voltage Vp of the AC signal to a value greater than or equal to the coercive field Ec of the piezoelectric material. Therefore, the sound pressure level of the vibration device can be enhanced, and self-polarization of the sound pressure level can be achieved.

[0168] Figures 7A to 7D is a graph showing the bipolar driving reliability with respect to the temperature of a vibration device according to an experimental example of the present disclosure. In Figures 7A to 7D the horizontal axis represents the frequency and the vertical axis represents the sound pressure level.

[0169] Figure 7A and Figure 7B show the sound pressure levels in the case where a vibration device including a BT-based piezoelectric material composition is manufactured as each of a normal device and a deteriorated device, and bipolar driving is performed at room temperature for 24 hours. Figure 7C and Figure 7DShows the sound pressure level when driving a normal device and a degraded device for 24 hours by bipolar driving at high temperature. Here, the normal device can be a device that has been polarized at a voltage twice to three times the Ec value, and the degraded device can be a device after the normal device has been depolarized at high temperature for 10 hours or longer. For example, the room temperature can be 25 °C, and the high temperature can be 60 °C. For example, depolarization can be a state where the sound pressure level is below 80% of the initial sound pressure level of the normal device. The driving voltage can be -21.2 V / 21.2 V, and the peak voltage Vp can be 21.2 Vp. For example, 21.2 Vp driving can be a voltage less than or equal to the coercive field Ec. In Figure 7A and Figure 7B , the thin solid line represents the initial sound pressure level, and the thick solid line represents the sound pressure level after bipolar driving for 24 hours.

[0170] Referring to Figure 7A , at room temperature, the initial sound pressure level of the normal device is 63.5 dB in the range of 300 Hz to 8 kHz and 63.5 dB in the range of 150 Hz to 20 kHz. The sound pressure level of the normal device after being driven by the bipolar method for 24 hours at room temperature is 63.5 dB in the range of 300 Hz to 8 kHz and 63.4 dB in the range of 150 Hz to 20 kHz. Therefore, in the sound pressure level of the normal device at room temperature, it can be seen that there is no difference in the sound pressure level even after bipolar driving.

[0171] Referring to Figure 7B , at room temperature, the initial sound pressure level of the degraded device is 51.7 dB in the range of 300 Hz to 8 kHz and 52.3 dB in the range of 150 Hz to 20 kHz. The sound pressure level of the degraded device after being driven by the bipolar method for 24 hours at room temperature is 51.7 dB in the range of 300 Hz to 8 kHz and 52.5 dB in the range of 150 Hz to 20 kHz. Therefore, in the sound pressure level of the degraded device at room temperature, it can be seen that there is no difference in the sound pressure level even after bipolar driving.

[0172] Referring to Figure 7A and Figure 7B , it can be seen that each of the normal device and the degraded device does not have a difference in the sound pressure level from the initial sound pressure level even after bipolar driving at room temperature.

[0173] Referring to Figure 7C, at room temperature, the initial sound pressure level of the normal device is 63.5 dB in the range of 300 Hz to 8 kHz and 63.4 dB in the range of 150 Hz to 20 kHz. The sound pressure level of the normal device after being driven by the bipolar method at high temperature for 24 hours is 54.0 dB in the range of 300 Hz to 8 kHz and 54.1 dB in the range of 150 Hz to 20 kHz. Compared with the initial sound pressure level, the sound pressure level of the normal device at high temperature has decreased by approximately 9.4 dB in the range of 300 Hz to 8 kHz and approximately 9.4 dB in the range of 150 Hz to 20 kHz. Therefore, during the driving of the normal device at high temperature, it can be seen that the sound pressure level decreases.

[0174] Referring to Figure 7D , at room temperature, the initial sound pressure level of the deteriorated device is 51.7 dB in the range of 300 Hz to 8 kHz and 52.5 dB in the range of 150 Hz to 20 kHz. The sound pressure level of the deteriorated device after being driven by the bipolar method at high temperature for 24 hours is 50.8 dB in the range of 300 Hz to 8 kHz and 51.5 dB in the range of 150 Hz to 20 kHz. Compared with the initial sound pressure level, the sound pressure level of the deteriorated device at high temperature has decreased by approximately 0.9 dB in the range of 300 Hz to 8 kHz and approximately 1.0 dB in the range of 150 Hz to 20 kHz. Therefore, it can be seen that the sound pressure level of the deteriorated device decreases at high temperature.

[0175] Referring to Figure 7C and Figure 7D , compared with the initial sound pressure level, it can be seen that after bipolar driving, the sound pressure level of each of the normal device and the deteriorated device decreases at high temperature. Therefore, when a vibration device including a BT-based piezoelectric material composition is driven at high temperature by bipolar driving for 24 hours, it can be seen that the sound pressure level decreases and the driving reliability decreases.

[0176] Figure 8A and Figure 8B are graphs showing the sound pressure level of the vibration device according to the experimental examples of the present disclosure with respect to frequency. In Figure 8A and Figure 8B , the horizontal axis represents frequency and the vertical axis represents sound pressure level.

[0177] According to Figure 8A and Figure 8B 's experimental examples, the vibration device has been configured to include the piezoelectric material of Formula 1 described above with reference to Figures 1 to 3 . In Figure 8A and Figure 8BAmong them, the driving voltage was set to -20V / 20V, and the driving time was set to 2 hours. The sound output characteristics of the vibrating device with respect to frequency were measured in an anechoic chamber. The measurement was carried out under the condition that the applied voltage was 5Vrms and the applied frequency signal was applied in a sine sweep manner within the range of 20Hz to 20kHz, and the measurement results were smoothed by 1 / 3 octave. The vibrating plate used was a SUS plate, and the width, height, and thickness of the vibrating plate were prepared to be 30mm, 30mm, and 0.5mm, respectively. Figure 8A and Figure 8B show the results obtained by measuring the sound pressure levels with respect to the frequencies of 100Hz and 1kHz. In Figure 8A and Figure 8B the thin solid line represents the initial sound pressure level at each frequency, the thick solid line represents the sound pressure level at each frequency after driving for 2 hours by the bipolar method, and the dashed line represents the sound pressure level at each frequency after depolarization at 100°C for 2 hours.

[0178] Table 2 below can be a table showing the initial sound pressure level, the sound pressure level after depolarization, and the sound pressure level after driving with respect to the frequency of the vibrating device.

[0179] [Table 2]

[0180]

[0181] Referring to Figure 8A and Figure 8B as well as Table 2, the initial sound pressure level was measured to be 62.80dB at both 100Hz and 1kHz. The sound pressure level after depolarization at 100°C for 2 hours was measured to be 47.07dB at 100Hz and 1kHz. The sound pressure level after driving for 2 hours by the bipolar method was measured to be 44.89dB at 100Hz and 49.50dB at 1kHz.

[0182] According to the present disclosure, compared with the initial sound pressure level, it can be seen that the sound pressure level decreased by about 18.07dB at 100Hz and about 13.38dB at 1kHz after driving for 2 hours by the bipolar method. Therefore, in one aspect according to the present disclosure, when the vibrating device is driven by the bipolar method, it can be seen that the sound pressure level decreases compared to the initial sound pressure level.

[0183] Figures 9A to 9C is a graph showing the sound pressure level of the vibrating device with respect to frequency according to one aspect of the present disclosure. In Figures 9A to 9C the horizontal axis represents the frequency and the vertical axis represents the sound pressure level.

[0184] According to Figure 9A and Figure 9B the experimental examples, the vibrating device was configured to include as referred to aboveFigures 1 to 3 The piezoelectric material of Formula 1 described. In Figures 9A to 9C , the drive voltage has been set to 0V / 40V, the peak voltage Vp has been set to 40Vp, and the drive time has been set to 2 hours. The method for measuring the sound pressure level of the vibration device relative to the frequency can be the same as Figure 8A and Figure 8B described. The vibration plate uses a SUS plate, and the width, height, and thickness of the vibration plate are prepared to be 30mm, 30mm, and 0.5mm, respectively. Figures 9A to 9C Shows the results obtained by measuring the sound pressure level relative to the frequencies of 100Hz, 1kHz, and 10kHz. In Figures 9A to 9C , the thin solid line represents the initial sound pressure level at each frequency, the thick solid line represents the sound pressure level at each frequency after driving for 2 hours by the monopole method, and the dashed line represents the sound pressure level at each frequency after depolarization at 60°C for 10 hours.

[0185] The following Table 3 can be a table showing the sound pressure level of the vibration device relative to the frequency.

[0186] [Table 3]

[0187]

[0188] Referring to Figures 9A to 9C and Table 3, all the initial sound pressure levels are measured to be 62.80dB at 100Hz, 1kHz, and 10kHz. The sound pressure levels after depolarization at 60°C for 24 hours are measured to be 50.63dB, 52.36dB, and 51.56dB at 100Hz, 1kHz, and 10kHz, respectively. The sound pressure levels after driving for 2 hours by the monopole method are measured to be 65.45dB, 58.90dB, and 47.87dB at 100Hz, 1kHz, and 10kHz, respectively.

[0189] According to the present disclosure, compared with the initial sound pressure level, it can be seen that the sound pressure level after driving for 2 hours by the monopole method increases by about 1.65dB at 100Hz, decreases by about 3.90dB at 1kHz, and decreases by about 14.93dB at 10kHz.

[0190] Therefore, in one aspect of the present disclosure, when the vibration device is driven by the monopole method, it can be seen that the sound pressure level recovers to 102% in the low audio band (e.g., 100Hz) and decreases in the mid-high audio band (e.g., 1kHz to 10kHz). For example, the reason for the decrease in the sound pressure level in the mid-high audio band (e.g., 1kHz to 10kHz) may be that when driven by a mid-high audio band signal, the vibration device deteriorates due to overcurrent or heat generated in the vibration device.

[0191] Figure 10A and Figure 10B is a graph showing the sound pressure level in the full frequency range of a vibration device according to an aspect of the present disclosure. Figure 10A and Figure 10B is a graph showing the sound pressure level in pink noise.

[0192] For example, in the case of measuring the sound pressure level of a vibration device, white noise or pink noise is used to evaluate the sound pressure level in the full frequency range, and in this case, since hearing evaluation or reliability evaluation takes into account the hearing ability of a person, pink noise can be used. Therefore, the inventors have evaluated the sound pressure level of the vibration device by using pink noise in order to evaluate the sound pressure level during driving in the full frequency range. The method of measuring the sound pressure level of the vibration device with respect to frequency can be the same as Figure 8A and Figure 8B described. In Figure 10A and Figure 10B , the horizontal axis represents frequency and the vertical axis represents sound pressure level. In Figure 10A , the driving voltage is 24V, the peak voltage Vp is 24V, and the driving time is 2 hours. In Figure 10B , the driving voltage is 47.5V, the peak voltage Vp is 47.5V, and the driving time is 2 hours. In Figure 10A and Figure 10B , the thin solid line represents the initial sound pressure level at each frequency, the thick solid line represents the sound pressure level at each frequency after driving for 2 hours by the monopole method, and the dashed line represents the sound pressure level at each frequency after depolarization at 60 °C for 10 hours. In Figure 10A , the peak voltage Vp has a value less than or equal to the coercive field Ec, and in Figure 10B , the peak voltage Vp has a value greater than or equal to the coercive field Ec.

[0193] The following Table 4 can be a table showing the sound pressure level with respect to frequencies from 150 Hz to 20 kHz.

[0194] [Table 4]

[0195]

[0196] Referring to Figure 10A and Table 4, at a peak voltage Vp of 24 Vp, the initial sound pressure level was measured to be 62.80 dB, the sound pressure level after depolarization at 60 °C for 10 hours or longer was measured to be 49.50 dB, and the sound pressure level after driving for 2 hours by the monopole method was measured to be 60.80 dB.

[0197] Therefore, according to the present disclosure, it can be seen that the sound pressure level after driving for 2 hours by the monopole method has decreased by approximately 2.0 dB in the peak voltage Vp of 24 Vp compared to the initial sound pressure level.

[0198] Referring to Figure 10B and Table 4, at a peak voltage Vp of 47.5 Vp, the initial sound pressure level was measured to be 62.80 dB, the sound pressure level after depolarization at 60 °C for 24 hours was measured to be 44.90 dB, and the sound pressure level after being driven by the monopole method for 2 hours was measured to be 64.90 dB.

[0199] Therefore, in one aspect according to the present disclosure, it can be seen that, compared with the initial sound pressure level, the sound pressure level after being driven by the monopole method for 2 hours increases by about 2.1 dB at the peak voltage Vp of 47.5 Vp.

[0200] Therefore, in one aspect of the present disclosure, in the case where the vibration device is driven by the monopole driving method with an AC signal of 0 V or more and the peak voltage Vp of the AC signal is set to a value greater than or equal to the coercive field Ec of the piezoelectric material, it can be seen that the sound pressure level of the vibration device is enhanced and self-polarization of the sound pressure level can be achieved.

[0201] Figure 11A and Figure 11B is a graph showing the sound pressure level of the piezoelectric device according to one aspect of the present disclosure with respect to the driving time.

[0202] This can be used to check the self-polarization effect of the sound pressure level based on the driving voltage, Figure 11A showing the case where 40 Vp (which is a voltage greater than or equal to the coercive field Ec) is set as the peak voltage Vp, Figure 11B showing the case where 24 Vp (which is a voltage less than or equal to the coercive field Ec) is set as the peak voltage Vp. Here, self-polarization can mean that the sound pressure level after driving does not decrease and does not recover compared with the initial sound pressure level. The measurement method of the sound pressure level can be the same as that in Figure 8A and Figure 8B . In Figure 11A and Figure 11B , the horizontal axis represents the frequency and the vertical axis represents the sound pressure level.

[0203] In Figure 11A , the frequency and the driving voltage are set to 100 Hz and 40 V respectively, and the driving time is set to 30 seconds, 1 minute, 3 minutes, and 11 minutes. In Figure 11A , the thin solid line represents the initial sound pressure level with respect to the frequency, and the dashed line represents the sound pressure level after depolarization at 60 °C for 24 hours. In Figure 11A , the thick short dash - single dash line, thick solid line, short dash - single dash line, and short dash - double dash line represent the sound pressure levels after being driven for 30 seconds, 1 minute, 3 minutes, and 11 minutes respectively.

[0204] In Figure 11BAmong them, the frequency and the driving voltage are set to 100 Hz and 24 V respectively, and the driving time is set to 1 minute, 3 minutes, 8 minutes, and 18 minutes. In Figure 11B Among them, the thin solid line represents the initial sound pressure level with respect to the frequency, and the dashed line 1 represents the sound pressure level after depolarization at 60 °C for 24 hours. In Figure 11B Among them, the dashed line 2, the thick solid line, the dash - single - dotted line, and the dash - double - dotted line represent the sound pressure levels after being driven for 1 minute, 3 minutes, 8 minutes, and 18 minutes respectively.

[0205] Table 5 below can be a table showing the sound pressure levels with respect to frequencies from 150 Hz to 20 kHz.

[0206] [Table 5]

[0207]

[0208] Referring to Figure 11A and Figure 11B and Table 5, the initial sound pressure level is 59.8 dB at the peak voltage Vp of 40 Vp and 24 Vp, and the sound pressure level after depolarization at 60 °C for 24 hours is 53.4 dB.

[0209] Referring to Figure 11A and Table 5, the sound pressure levels of the samples driven for 30 seconds, 1 minute, 3 minutes, and 11 minutes by the monopole method at the peak voltage Vp of 40 Vp are measured to be 55.1 dB, 60.3 dB, 60.5 dB, and 60.5 dB respectively. The differences between the sound pressure levels after driving and the sound pressure levels of the samples driven for 30 seconds, 1 minute, 3 minutes, and 11 minutes by the monopole method at the peak voltage Vp of 40 Vp are measured to be - 4.7 dB, 0.5 dB, 0.6 dB, and 0.6 dB respectively. Therefore, in one aspect of the present disclosure, when the vibration device is driven by the monopole method at 40 Vp (which is the peak voltage Vp greater than or equal to the coercive field Ec) for 1 minute or longer, it can be seen that self - polarization of the sound pressure level can be achieved.

[0210] Referring to Figure 11BAs for Table 5, the sound pressure levels of the samples driven by the monopole method for 1 minute, 3 minutes, 8 minutes, and 18 minutes at a peak voltage Vp of 24 Vp were measured to be 53.4 dB, 53.9 dB, 54.6 dB, and 55.1 dB, respectively. The differences between the sound pressure levels after driving and the sound pressure levels of the samples driven by the monopole method for 1 minute, 3 minutes, 8 minutes, and 18 minutes at a peak voltage Vp of 24 Vp were measured to be -6.4 dB, -5.9 dB, -5.2 dB, and -4.7 dB, respectively. Therefore, in one aspect of the present disclosure, in the case where the vibration device is driven by the monopole method at 24 Vp (which is the peak voltage Vp less than or equal to the coercive field Ec), it can be seen that the self-polarization of the sound pressure level cannot be achieved.

[0211] Therefore, in one aspect of the present disclosure, in the case where the vibration device is driven by the monopole driving method with an AC signal of 0 V or more and the peak voltage Vp of the AC signal is set to a value greater than or equal to the coercive field Ec of the piezoelectric material, it can be seen that the sound pressure level of the vibration device is enhanced and the self-polarization of the sound pressure level can be achieved.

[0212] Figure 12 FIG. is a diagram showing a car audio device according to one aspect of the present disclosure.

[0213] Referring to Figure 12 , the in-vehicle audio device according to one aspect of the present disclosure may include an audio device 500. The audio device 500 may be provided or equipped in the vehicle to output sound S to the interior space IS of the vehicle 800.

[0214] The vehicle 800 may include interior materials (or interior finishing materials) 850. In the following description, for convenience of description, the "interior material 850" may be referred to as the "vehicle interior material 850".

[0215] The vehicle interior material 850 may include all components constituting the interior of the vehicle 800, or may include all components provided in the interior space IS of the vehicle 800. For example, the vehicle interior material 850 may be an interior member or an interior finishing member of the vehicle 800, but the aspects of the present disclosure are not limited thereto.

[0216] The vehicle interior material 850 according to one aspect of the present disclosure may be configured to be exposed to the interior space or the interior space IS of the vehicle 800 in the interior space of the vehicle 800. For example, the vehicle interior material 850 may be provided to cover one surface (or inner surface) of at least one of the main frame (or vehicle body), side frame (or side body), door frame (or door body), handle frame (or steering hub), and seat frame exposed to the interior space IS of the vehicle 800.

[0217] The vehicle interior material 850 according to an aspect of the present disclosure may include an instrument panel, an interior pillar material (or pillar trim), a floor interior material (or floor carpet), a roof interior material (or roof lining), a door interior material (or door trim), a handle interior material (or steering cover), a seat interior material, a rear package interior material (or rear seat frame), an overhead console (or interior lighting interior material), a rearview mirror, a storage box, and a sun visor, but the aspects of the present disclosure are not limited thereto.

[0218] The vehicle interior material 850 according to an aspect of the present disclosure may include one or more of metal, wood, rubber, plastic, glass, fiber, cloth, paper, mirror, leather, and carbon, but the aspects of the present disclosure are not limited thereto. The vehicle interior material 850 including a plastic material may be an injection-molded material implemented by an injection molding process using a thermosetting resin or a thermoplastic resin, but the aspects of the present disclosure are not limited thereto. The vehicle interior material 850 including a fiber material may include one or more of synthetic fiber, carbon fiber (or aramid fiber), and natural fiber, but the aspects of the present disclosure are not limited thereto. The vehicle interior material 850 including a fiber material may include a fabric sheet, a knitted sheet, or a nonwoven fabric, but the aspects of the present disclosure are not limited thereto. For example, the interior material 20c or the outer surface member including a fiber material may be a fabric member, but the aspects of the present disclosure are not limited thereto. For example, the paper may be cone paper. For example, the cone paper may be pulp or plastic foam, but the aspects of the present disclosure are not limited thereto. The vehicle interior material 850 including a leather material may include natural leather or artificial leather, but the aspects of the present disclosure are not limited thereto.

[0219] The vehicle interior material 850 according to an aspect of the present disclosure may include one or more of a flat portion and a curved portion. For example, the vehicle interior material 850 may have a structure corresponding to the structure of the corresponding vehicle structural material, or may have a structure different from the structure of the corresponding vehicle structural material.

[0220] According to an aspect of the present disclosure, an audio device 500 may be provided at the vehicle interior material 850. The audio device 500 may vibrate the vehicle interior material 850 to generate a sound S based on the vibration of the vehicle interior material 850. For example, the audio device 500 may directly vibrate the vehicle interior material 850 to generate a sound S based on the vibration of the vehicle interior material 850.

[0221] For example, the audio device 500 may be configured with one of the vibration devices according to one or more aspects of the present disclosure described above Figures 1 to 4 as described.

[0222] For example, the audio device 500 may be configured to vibrate the vehicle interior material 850 to output sound S to the interior space or cabin space IS of the vehicle 800. Accordingly, the vehicle interior material 850 may serve as a sound vibrating plate. The vehicle interior material 850 may be a vibrating plate for outputting sound S, a sound vibrating plate, or a sound generating plate. For example, the vehicle interior material 850 may have a size larger than that of the audio device 500, but aspects of the present disclosure are not limited thereto.

[0223] For example, the audio device 500 may be disposed at one or more of a dashboard, an inner pillar material, an inner floor material, an inner roof material, an inner door material, an inner handle material, and an inner seat material, or may be disposed in one or more of a rear package inner material, a top console, a rearview mirror, a storage box, and a sun visor.

[0224] The audio device 500 according to one aspect of the present disclosure may vibrate the corresponding vehicle interior material 850 through at least one or more of one or more audio devices 500 disposed at the vehicle interior material 850 to output realistic sound S and / or stereo (including multi-channel) to the cabin space IS of the vehicle 800.

[0225] Figure 13 is a perspective view of a display device according to one aspect of the present disclosure. Figure 14 is along according to one aspect of the present disclosure Figure 13 a cross-sectional view taken along the line I-I' shown in

[0226] Referring to Figure 13 and Figure 14 According to one aspect of the present disclosure, a vibration driving device may include a vibration member 100 and a piezoelectric device 200.

[0227] The vibration member 100 may be configured to display an image. The piezoelectric device 200 may be disposed at the rear surface (or back surface) of the vibration member 100. For example, the piezoelectric device 200 may be configured to vibrate the vibration member 100.

[0228] For example, the vibration member 100 may output sound based on the vibration of the piezoelectric device 200. For example, the vibration member 100 may be a vibrating object, a display panel, a vibrating plate, or a front member, but aspects of the present disclosure are not limited thereto.

[0229] For example, the vibration member 100 or the vibrating object may include one or more of a display panel having pixels configured to display an image, a screen panel on which an image is projected from a display device, a lighting panel, a sign panel, an interior material of a vehicle, a vehicle window glass, an exterior material of a vehicle, a ceiling material of a building, an interior material of a building, a building window glass, an interior material of an aircraft, an aircraft window glass, wood, plastic, glass, metal, cloth, fiber, paper, rubber, leather, and a mirror, but aspects of the present disclosure are not limited thereto.

[0230] In the following description, it is described that the vibration member 100 is the display panel 100.

[0231] The display panel 100 may display an electronic image, a digital image, a still image, or a video image. For example, the display panel 100 may output light to display an image. The display panel 100 may be a curved display panel, or may be any type of display panel, such as a liquid crystal display panel, an organic light emitting display panel, a quantum dot light emitting display panel, a micro light emitting diode display panel, and an electrophoretic display panel, etc. The display panel 100 may be a flexible display panel. For example, the display panel 100 may be a flexible light emitting display panel, a flexible electrophoretic display panel, a flexible electro-wetting display panel, a flexible micro light emitting diode display panel, or a flexible quantum dot light emitting display panel, but aspects of the present disclosure are not limited thereto.

[0232] The display panel 100 according to an aspect of the present disclosure may include a display area AA (or an active area) for driving and displaying an image according to a plurality of pixels. In addition, the display panel 100 may further include a non-display area IA surrounding the display area AA, but aspects of the present disclosure are not limited thereto.

[0233] The piezoelectric device 200 may vibrate the display panel 100 at the rear surface of the display panel 100, thereby providing sound and / or haptic feedback based on the vibration of the display panel 100 to a user (or a viewer). The piezoelectric device 200 may be implemented at the rear surface of the display panel 100 in such a way as to directly vibrate the display panel 100.

[0234] As an aspect of the present disclosure, the piezoelectric device 200 may vibrate according to a voice signal synchronized with the image displayed on the display panel 100 to vibrate the display panel 100. As another aspect of the present disclosure, the piezoelectric device 200 may be disposed at the display panel 100, or may vibrate according to a haptic feedback signal (or a haptic feedback signal) synchronized with a user touch applied to a touch panel (or a touch sensor layer) embedded in the display panel 100 to vibrate the display panel 100. Accordingly, the display panel 100 may vibrate based on the vibration of the piezoelectric device 200 to provide at least one of sound and haptic feedback to a user (or a viewer).

[0235] A piezoelectric device 200 according to an aspect of the present disclosure may be implemented to have a size corresponding to a display area AA of a display panel 100. The size of the piezoelectric device 200 may be 0.9 times to 1.1 times the size of the display area AA, but the aspect of the present disclosure is not limited thereto. For example, the size of the piezoelectric device 200 may be the same as or smaller than the size of the display area AA. For example, the size of the piezoelectric device 200 may be the same as or approximately the same as the display area AA of the display panel 100. Thus, the piezoelectric device 200 may cover most of the display panel 100 and vibrations generated by the piezoelectric device 200 may vibrate the entire portion of the display panel 100. Thus, sound localization may be high and user satisfaction may be improved. In addition, the contact area (or panel coverage rate) between the display panel 100 and the piezoelectric device 200 may increase, and thus, the vibration area of the display panel 100 may increase, thereby improving sound in the mid- and low-audio bands generated based on the vibration of the display panel 100. Also, the piezoelectric device 200 applied to a large-size display device may vibrate the entire display panel 100 having a large size (or large area), and thus, sound localization based on the vibration of the display panel 100 may be further enhanced, thereby achieving an improved sound effect. Accordingly, a piezoelectric device 200 according to an aspect of the present disclosure may be disposed at the rear surface of the display panel 100 to vibrate the display panel 100 sufficiently in the vertical (or front-rear) direction, thereby outputting desired sound to a front area in front of a vibration driving device or a display device.

[0236] The piezoelectric device 200 according to one aspect of the present disclosure can be implemented as a film type. Since the piezoelectric device 200 can be implemented as a film type, it can have a thickness thinner than that of the display panel 100. Therefore, the thickness of the display device does not increase due to the arrangement of the piezoelectric device 200. For example, the piezoelectric device 200 can use the display panel 100 as a sound diaphragm. For example, the piezoelectric device 200 can be referred to as a sound generation module, a vibration generation device, a film actuator, a film type piezoelectric composite actuator, a film speaker, a film type piezoelectric speaker, or a film type piezoelectric composite speaker, which uses the display panel 100 as a diaphragm, but the aspects of the present disclosure are not limited thereto. As another aspect of the present disclosure, the piezoelectric device 200 may not be disposed at the rear surface of the display panel 100 and may be applied to a vibrating object instead of the display panel. For example, the vibrating object can be one or more of a non-display panel, wood, metal, plastic, glass, cloth, paper, mirror, fiber, rubber, leather, vehicle interior material, vehicle glass window, building interior ceiling, building glass window, building interior material, aircraft interior material, and aircraft glass window, etc., but the aspects of the present disclosure are not limited thereto. For example, the non-display panel can be a light-emitting diode lighting panel (or device), an organic light-emitting lighting panel (or device), or an inorganic light-emitting lighting panel (or device), etc., but the aspects of the present disclosure are not limited thereto. In this case, the vibrating object can be applied as a diaphragm, and the piezoelectric device 200 can vibrate the vibrating object to output sound.

[0237] The piezoelectric device 200 according to one aspect of the present disclosure may further include a vibration structure 230 and a connection member 210 disposed between the vibration structure 230 and the display panel 100. The piezoelectric device 200 according to one aspect of the present disclosure can be the vibration device described with reference to Figures 1 to 3 and the vibration structure 230 can be the vibration generation unit described with reference to Figures 1 to 3 description.

[0238] According to one aspect of the present disclosure, the connection member 210 may include at least one substrate and may include an adhesive layer attached to one surface or both surfaces of the substrate, or may be configured as a single layer of an adhesive layer.

[0239] For example, the connection member 210 may include a foam pad, a double-sided foam pad, a double-sided tape, a double-sided foam tape, a double-sided adhesive, or an adhesive, etc., but the aspects of the present disclosure are not limited thereto. For example, the adhesive layer of the connection member 210 may include an epoxy-based polymer, an acrylic-based polymer, a silicone-based polymer, or a urethane-based polymer, but the aspects of the present disclosure are not limited thereto.

[0240] The display panel 100 according to one aspect of the present disclosure may further include a support member 300 disposed at the rear surface of the display panel 100.

[0241] The support member 300 may cover the rear surface of the display panel 100. For example, the support member 300 may cover the entire rear surface of the display panel 100 with a gap space GS therebetween. For example, the support member 300 may include at least one or more of a glass material, a metal material, and a plastic material. For example, the support member 300 may be a rear structure or an assembly structure. For example, the support member 300 may be a cover bottom, a plate bottom, a rear cover, a base frame, a metal frame, a metal chassis, a chassis base, or an m-chassis, etc., but the aspects of the present disclosure are not limited thereto. Accordingly, the support member 300 may be implemented as any type of frame or plate-like structure provided at the rear surface of the display panel 100.

[0242] The device according to an aspect of the present disclosure may further include an intermediate frame 400.

[0243] The intermediate frame 400 may be disposed between the rear periphery of the display panel 100 and the front periphery of the support member 300. The intermediate frame 400 may support at least one or more of the rear periphery of the display panel 100 and the front periphery of the support member 300, and may surround one or more of the side surfaces of each of the display panel 100 and the support member 300. The intermediate frame 400 may form a gap space GS between the display panel 100 and the support member 300. The intermediate frame 400 may be referred to as an intermediate cabinet, an intermediate cover, an intermediate chassis, etc., but the aspects of the present disclosure are not limited thereto.

[0244] The intermediate frame 400 according to an aspect of the present disclosure may include a first support portion 410 and a second support portion 430.

[0245] The first support portion 410 may be disposed between the rear periphery of the display panel 100 and the front periphery of the support member 300, and thus, may form a gap space GS between the display panel 100 and the support member 300. The front surface of the first support portion 410 may be coupled or connected to the rear periphery of the display panel 100 through a first frame connection member 401. The rear surface of the first support portion 410 may be coupled or connected to the front periphery of the support member 300 through a second frame connection member 403. For example, the first support portion 410 may include a single picture frame structure having a square shape or a frame structure having a plurality of dividing bar shapes, but the aspects of the present disclosure are not limited thereto.

[0246] The second support part 430 may be perpendicularly coupled to the outer surface of the first support part 410 parallel to the thickness direction Z of the vibration driving device. The second support part 430 may surround one or more of the outer surface of the display panel 100 and the outer surface of the support member 300, thereby protecting the outer surfaces of each of the display panel 100 and the support member 300. The first support part 410 may protrude from the inner surface of the second support part 430 toward the gap space GS between the display panel 100 and the support member 300.

[0247] The device according to one aspect of the present disclosure may be applied to a mobile device, a video phone, a smart watch, a watch phone, a wearable device, a foldable device, a rollable device, a bendable device, a flexible device, a curved device, a sliding device, a variable device, an electronic notepad, an e-book, a portable multimedia player (PMP), a personal digital assistant (PDA), an MP3 player, a mobile medical device, a desktop personal computer (PC), a laptop PC, a netbook computer, a workstation, a navigation device, an in-vehicle navigation device, an automatic display device, an in-vehicle device, a theater device, a theater display device, a television, a wallpaper display device, a signage device, a gaming device, a laptop, a monitor, a camera, a video camera, a household appliance, etc. In addition, the vibration device according to some aspects of the present disclosure may be applied to (or included in) an organic light-emitting lighting device or an inorganic light-emitting lighting device. When the vibration device is applied to (or included in) a lighting device, the lighting device may act as both lighting and a speaker. Additionally, when the vibration device of the present disclosure is applied to (or included in) a mobile device or the like, the vibration device may act as one or more of a speaker, a receiver, and a haptic device, but the aspects of the present disclosure are not limited thereto.

[0248] The vibration driving device according to one or more aspects of the present disclosure may be described as follows.

[0249] The vibration driving device according to one or more aspects of the present disclosure may include a vibration member, and a vibration device disposed at the rear surface of the vibration member and configured to vibrate the vibration member according to a driving signal. The driving signal is an alternating current (AC) signal of 0 V or more.

[0250] According to one or more aspects of the present disclosure, the vibration driving device may further include a driving circuit configured to supply the driving signal to the vibration device. The vibration device may include a vibration generating part including a piezoelectric material, and the driving circuit may include an amplifier configured to output an AC signal to the vibration generating part.

[0251] According to one or more aspects of the present disclosure, the vibration generating part may include a vibration layer including a piezoelectric material, a first electrode layer disposed at a first surface of the vibration layer, and a second electrode layer disposed at a second surface of the vibration layer different from the first surface.

[0252] According to one or more aspects of the present disclosure, a piezoelectric material can be represented by Formula 1.

[0253] [Formula 1]

[0254] aBa(Ti 1-y ,Zr y )O 3-b (Ba 1-x ,Ca x )TiO3 + c mol% A

[0255] Wherein, A can be TiO2, CuO, KF, FeO3 or NiO, 0.40 ≤ a ≤ 0.60, 0.40 ≤ b ≤ 0.60, 0.00 < c ≤ 1.00, 0.05 ≤ x ≤ 0.30, 0.10 ≤ y ≤ 0.20.

[0256] According to one or more aspects of the present disclosure, the coercive field of the piezoelectric material can have a range of 1.8 kV / cm to 2.3 kV / cm.

[0257] According to one or more aspects of the present disclosure, the peak voltage of the AC signal can have a value greater than or equal to the coercive field of the piezoelectric material.

[0258] According to one or more aspects of the present disclosure, the peak voltage of the AC signal can be 40 Vp to 60 Vp.

[0259] According to one or more aspects of the present disclosure, an amplifier can include a first output terminal configured to output a first vibration driving signal and a second output terminal configured to output a second vibration driving signal.

[0260] According to one or more aspects of the present disclosure, a vibration device can include a first cover member connected to a first surface of a vibration generating portion, a second cover member connected to a second surface of the vibration generating portion opposite to the first surface, and a signal cable including a first signal line and a second signal line electrically connected to the vibration generating portion.

[0261] According to one or more aspects of the present disclosure, the first output terminal can be electrically connected to a first electrode layer through the first signal line, and the second output terminal can be electrically connected to a second electrode layer through the second signal line.

[0262] According to one or more aspects of the present disclosure, the vibration member may include one or more of a display panel having a plurality of pixels for displaying an image, a screen panel onto which an image is projected from a display device, a light-emitting diode illumination panel, an organic light-emitting illumination panel, an inorganic light-emitting illumination panel, a sign panel, an interior material of a vehicle, an exterior material of a vehicle, a vehicle window glass, an interior material of a vehicle seat, a ceiling material of a building, an interior material of a building, a building window glass, an interior material of an aircraft, an aircraft window glass, wood, plastic, glass, metal, cloth, fiber, paper, rubber, leather, carbon, and a mirror.

[0263] The above-described features, structures, and effects of the present disclosure are included in at least one aspect of the present disclosure, but are not limited to only one aspect. In addition, the features, structures, and effects described in at least one aspect of the present disclosure may be achieved by those skilled in the art through combinations or modifications of other aspects. Therefore, the content associated with the combinations and modifications should be construed as being within the scope of the present disclosure.

[0264] It will be apparent to those skilled in the art that various modifications and variations can be made to the present disclosure without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure is intended to cover modifications and variations of the present disclosure as long as they fall within the scope of the appended claims and their equivalents.

Claims

1. A vibration driven device, comprising: Vibrating components; as well as a vibration device that is provided at a rear surface of the vibration member and vibrates the vibration member according to a driving signal, The driving signal is an alternating current signal above 0V, that is, an AC signal.

2. The vibration driven device according to claim 1, further comprising a drive circuit configured to supply the drive signal to the vibration device, in, The vibration device includes a vibration generating portion including a piezoelectric material, and The driving circuit includes an amplifier configured to output the AC signal to the vibration generating portion.

3. The vibration driven device according to claim 2, wherein: The vibration generating unit comprises: a vibration layer, the vibration layer comprising a piezoelectric material; a first electrode layer, the first electrode layer being located at a first surface of the vibration layer; and A second electrode layer is located at a second surface of the vibration layer different from the first surface.

4. The vibration driven device according to claim 3, wherein: The piezoelectric material is expressed as Formula 1, [Formula 1] aBa(Ti 1-y ,Zr y )YOU ARE 3-b (Ba 1-x ,Ca x )TiO3+c molsA Where A is TiO2, CuO, KF, FeO3 or NiO, 0.40 <a<0.60,0.40<b<0.60,0.00<c≤1.00,0.05<x<0.30,0.10≤y≤0.20。 5. The vibration driven device according to claim 3, wherein: The coercive field of the piezoelectric material has a range of 1.8 kV / cm to 2.3 kV / cm.

6. The vibration driven device according to claim 5, wherein: A peak voltage of the AC signal has a value greater than or equal to the coercive field of the piezoelectric material.

7. The vibration driven device according to claim 6, wherein: The peak voltage of the AC signal is 40Vp to 60Vp.

8. The vibration driven device according to claim 3, wherein: The amplifier comprises: a first output terminal configured to output a first vibration driving signal; and A second output terminal is configured to output a second vibration driving signal.

9. The vibration driven device according to claim 8, wherein: The vibration device comprises: a first cover member connected to a first surface of the vibration generating portion; a second cover member connected to a second surface of the vibration generating portion opposite to the first surface; and A signal cable includes a first signal line and a second signal line electrically connected to the vibration generating portion.

10. The vibration driven device according to claim 9, wherein: The first output terminal is electrically connected to the first electrode layer through the first signal line, and The second output terminal is electrically connected to the second electrode layer through the second signal line.

11. The vibration driven device according to claim 1, wherein: The vibration component includes a display panel having multiple pixels for displaying an image, a screen panel on which an image is projected from a display device, a light emitting diode lighting panel, an organic light emitting lighting panel, an inorganic light emitting lighting panel, a signage panel, an interior material of a vehicle, an exterior material of a vehicle, a glass window of a vehicle, an interior material of a seat of a vehicle, a ceiling material of a building, an interior material of a building, a glass window of a building, an interior material of an aircraft, a glass window of an aircraft, wood, plastic, glass, metal, cloth, fiber, paper, rubber, leather, carbon and one or more of a mirror.

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