Piezoelectric material composition, method of manufacturing same, piezoelectric device, and device including piezoelectric device

Abstract

A piezoelectric material composition may include a first material, a second material in the first material, and a third material between the first material and the second material. The first material, the second material, and the third material all do not include lead. The third material may be bonded to each of the first material and the second material and may act as a buffer between the first material and the second material. The present disclosure also proposes a method of manufacturing a piezoelectric material composition, a piezoelectric device, and an apparatus including such a piezoelectric device.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Korean Patent Application No. 10-2023-0173806, filed on December 4, 2023, which is hereby incorporated by reference as if fully set forth in this application. Technical Field

[0003] The present disclosure relates to a piezoelectric material composition, a method of manufacturing the composition, a piezoelectric device, and an apparatus including the piezoelectric device. Background Art

[0004] Piezoelectric materials are widely used as materials for components such as ultrasonic vibrators, transducers, and actuators used in many fields such as ultrasonic devices, imaging devices, sound devices, communication devices, and sensors. Summary of the invention

[0005] The inventors have recognized that the following problems may occur in practical applications of the developed piezoelectric materials.

[0006] Based on Pb(Zr,Ti)O 3 The material of zirconium tantalum (PZT) has high piezoelectric properties and is therefore used as a piezoelectric material. However, lead (Pb) is a highly toxic material and is highly volatile during the sintering process, thus causing serious environmental pollution.

[0007] Therefore, since PZT piezoelectric materials, which occupy the vast majority of piezoelectric materials, cause environmental pollution problems, it is necessary to develop a lead-free piezoelectric material. Compared with PZT piezoelectric materials, lead-free piezoelectric materials have lower piezoelectric properties, so high piezoelectric properties are required.

[0008] One embodiment of the present disclosure is to provide a piezoelectric material composition that may not contain lead and may have higher piezoelectric properties.

[0009] One embodiment of the present disclosure is directed to a method of manufacturing a piezoelectric material composition, which can orient grains of a piezoelectric material using a template to provide a piezoelectric material composition having high piezoelectric characteristics, thereby enhancing piezoelectric characteristics.

[0010] One embodiment of the present disclosure is to provide a method for manufacturing a piezoelectric material composition, which can coat or form a buffer material on the surface of a seed crystal used as a template, thereby minimizing inter-interface defects between a matrix material and the seed crystal.

[0011] One embodiment of the present disclosure is directed to providing a piezoelectric device having high piezoelectric characteristics and a device including the piezoelectric device.

[0012] Other features, advantages and embodiments of the present disclosure have been set forth in the present disclosure, will be apparent from the present disclosure, or can be learned by practicing the inventive concepts provided by the present disclosure. Other features, advantages and embodiments of the present disclosure can be realized and achieved by the description provided in the present disclosure, or the description derived therefrom, the claims of the present disclosure, and the accompanying drawings.

[0013] To achieve the above and other advantages and embodiments of the present disclosure, as embodied and broadly described herein, in one or more embodiments, a piezoelectric material composition may include a first material, a second material in the first material, and a third material between the first material and the second material. The first material, the second material, and the third material all do not contain lead. The third material may be bonded to each of the first material and the second material, and may function as a buffer between the first material and the second material.

[0014] According to a method for manufacturing a piezoelectric material composition according to an embodiment of the present disclosure, the method may include: a step of mixing a matrix material with a seed material to prepare a slurry, wherein a buffer material is formed on the seed material; a step of molding the slurry to prepare a green tape; and a step of sintering the green tape to prepare a sintered object. The sintered object may include a piezoelectric material composition. The piezoelectric material composition may include a first material, a second material in the first material, and a third material between the first material and the second material. The first material, the second material, and the third material all do not contain lead. The third material may be bonded to each of the first material and the second material, and may act as a buffer between the first material and the second material.

[0015] According to a piezoelectric device of one embodiment of the present disclosure, the piezoelectric device may include: a piezoelectric device layer; a first electrode portion disposed at a first surface of the piezoelectric device layer; and a second electrode portion disposed at a second surface of the piezoelectric device layer different from the first surface. The piezoelectric device layer may include a piezoelectric material composition. The piezoelectric material composition may include a first material, a second material in the first material, and a third material between the first material and the second material. The first material, the second material, and the third material all do not contain lead. The third material may be bonded to each of the first material and the second material, and may function as a buffer between the first material and the second material.

[0016] An apparatus according to one embodiment of the present disclosure may include a vibration member and a piezoelectric device. A piezoelectric device according to one embodiment of the present disclosure may include a piezoelectric device layer, a first electrode portion disposed at a first surface of the piezoelectric device layer, and a second electrode portion disposed at a second surface of the piezoelectric device layer different from the first surface. The piezoelectric device layer may include a piezoelectric material composition. The piezoelectric material composition may include a first material, a second material in the first material, and a third material between the first material and the second material. The first material, the second material, and the third material all do not contain lead. The third material may be bonded to each of the first material and the second material, and may act as a buffer between the first material and the second material.

[0017] According to one embodiment of the present disclosure, since a piezoelectric material composition does not include lead (Pb) and has high piezoelectric characteristics, a piezoelectric device and a display apparatus each including the piezoelectric material composition may be driven with a low driving voltage.

[0018] According to one embodiment of the present disclosure, a method of manufacturing a piezoelectric material composition can significantly reduce time and cost, thereby significantly improving productivity.

[0019] According to one embodiment of the present disclosure, productivity can be improved, thereby optimizing the production process.

[0020] According to one embodiment of the present disclosure, since the piezoelectric material composition does not include lead, production limiting materials can be reduced and replacement of harmful materials can be achieved, so that an environmentally friendly piezoelectric material composition can be provided.

[0021] According to an embodiment of the present disclosure, a buffer material may be coated on the surface of a seed crystal or form the surface of a seed crystal, thereby providing a piezoelectric material composition for minimizing interfacial defects between a matrix material and a seed crystal.

[0022] Other systems, methods, features and advantages will be or will become apparent to one skilled in the art upon review of the following figures and detailed description. All such additional systems, methods, features and advantages are intended to be included within this specification, fall within the scope of the present disclosure, and be protected by the appended claims. Nothing in this section shall be construed as limiting these claims. Other aspects and advantages are discussed below in conjunction with embodiments of the present disclosure.

[0023] It is to be understood that both the foregoing description and the following description of the present disclosure are exemplary and explanatory and are intended to provide further explanation of the disclosure as claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this application, illustrate embodiments of the disclosure and together with the description serve to explain the principle of the disclosure.

[0025] Figure 1 is a cross-sectional view showing a piezoelectric device according to one embodiment of the present disclosure;

[0026] Figure 2A and Figure 2B is a schematic diagram showing an interface between a seed crystal and a base material of a piezoelectric device according to a comparative example and an embodiment of the present disclosure;

[0027] Figure 3 is a schematic diagram illustrating a method of manufacturing a piezoelectric device according to an embodiment of the present disclosure;

[0028] Figure 4 is a schematic diagram showing a method for manufacturing a base material of a piezoelectric material composition according to one embodiment of the present disclosure;

[0029] Figure 5 is a schematic diagram showing a method for manufacturing a seed material of a piezoelectric material composition according to one embodiment of the present disclosure;

[0030] Figure 6 is a schematic diagram showing a vehicle-mounted sound device according to an embodiment of the present disclosure;

[0031] Figure 7 is a perspective view of a display device according to an embodiment of the present disclosure;

[0032] Figure 8 According to one embodiment of the present disclosure, Figure 7 A cross-sectional view taken along line II' of ; and

[0033] Fig. 9 is a diagram showing an embodiment according to the present disclosure Figure 7Schematic diagram of a piezoelectric device. DETAILED DESCRIPTION

[0034] Exemplary embodiments of the present disclosure are now described in detail, examples of which may be illustrated in the accompanying drawings. In the following description, if it is determined that a detailed description of related known functions or configurations would unnecessarily obscure the main points of the inventive concept, the detailed description of these known functions or configurations may be omitted, or may be briefly provided for the sake of brevity. The order of processing steps and / or operations described is only an example, and the order of steps and / or operations is not limited to the order set forth herein and may be changed in an order known in the art, except for steps and / or operations that must be performed in a specific order.

[0035] The exemplary embodiments described with reference to the accompanying drawings illustrate the advantages and features of the present disclosure and their implementation methods. However, the present disclosure can be embodied in different forms and should not be construed as being limited to the exemplary embodiments set forth herein. On the contrary, these embodiments can be provided so that the present disclosure can be thorough and complete, to help those skilled in the art fully understand the scope of the present disclosure.

[0036] The shapes, sizes, areas, ratios, angles, numbers, etc. shown in the accompanying drawings describe various exemplary embodiments of the present disclosure, but these are merely examples. Therefore, the present disclosure is not limited to the description in the accompanying drawings. Unless otherwise specified, the same reference numerals generally represent the same elements throughout the specification.

[0037] Where terms such as "including," "having," "comprising," "containing," "consisting of," "made of," or "formed of" are used, one or more other elements may be added unless more restrictive terms such as "only" are used. The terms and names used in the present disclosure are only used to describe specific embodiments and are not intended to limit the scope of the present disclosure. Elements described in the singular are intended to include plural elements, and vice versa, unless the context clearly indicates otherwise.

[0038] Unless otherwise specified, the word "exemplary" is used to mean serving as an example or illustration. The embodiments are example embodiments. The embodiments are example embodiments. Any implementation described herein as "exemplary" is not necessarily intended to be preferred or advantageous over other implementations.

[0039] In one or more embodiments, elements, features, or corresponding information (e.g., level, range, dimension, size, etc.) are interpreted as including an error or tolerance range, even if no explicit description of such error or tolerance range is provided. The error or tolerance range may be caused by various factors (e.g., process factors, internal or external influences, noise, etc.). In addition, the term "may" encompasses all meanings of the term "can".

[0040] When describing the positional relationship between two parts, for example, using "on", "above", "below", "above", "below", "on", "below", "near", "adjacent", "adjacent", "beside", "adjacent", etc., one or more other parts may be located between the two parts, unless more restrictive terms such as "immediately", "directly", or "closely" are used. For example, when a structure is described as being positioned "on", "above", "below", "above", "below", "below", "near", "adjacent", "adjacent", "beside", "adjacent", etc. to another structure, the description should be interpreted as including the case where the structures are in contact with each other and the case where one or more additional structures are arranged or inserted between them. In addition, unless otherwise expressly stated, the terms "front", "back", "back", "left", "right", "top", "bottom", "downward", "upward", "up", "down", "upward", "down", "column", "row", "vertical", "horizontal", etc. refer to an arbitrary reference system.

[0041] When describing temporal relationships, when the temporal order is described as, for example, "after", "subsequently", "next", "before", "previous", "preceding", etc., discontinuous or non-sequential situations may be included unless more restrictive terms such as "just", "immediately" or "directly" are used.

[0042] It should be understood that although the terms "first", "second", "A", "B", "(a)", "(b)", etc. can be used to describe various elements in this article, these elements should not be limited by these terms, for example, should not be limited to a specific order, priority or number of elements. These terms are only used to distinguish one element from another element. For example, without departing from the scope of this disclosure, the first element can be referred to as the second element, and similarly, the second element can be referred to as the first element. In addition, the first element, the second element, etc. can be arbitrarily named according to the convenience of those skilled in the art without departing from the scope of this disclosure. The terms "first", "second", "A", "B", "(a), "(b)", etc. can be used to distinguish and distinguish parts from each other, but the function or structure of the parts is not limited by the ordinal number or the name of the parts in front of the parts, and the terms "first", "second", "A", "B", "(a), "(b)", etc. are not used to define the essence, sequence, basis, order or quantity of the elements.

[0043] When an element or layer is described as being “connected,” “coupled,” or “attached” to another element or layer, unless otherwise specified, the element or layer may be not only directly connected, coupled, or attached to the other element or layer, but may also be indirectly connected, coupled, or attached to the other element or layer with one or more intermediate elements or layers disposed or interposed therebetween.

[0044] When an element or layer is described as “contacting,” “overlapping,” etc., another element or layer, unless otherwise specified, the element or layer may not only be directly in contact with, overlap, etc., but may also be indirectly in contact with, overlap, etc., with another element or layer, with one or more intermediate elements or layers disposed or interposed between the elements or layers.

[0045] The term "at least one" should be understood to include any and all combinations of one or more associated listed items. For example, the meaning of "at least one of the first, second, or third item" covers the three listed items, the combination of any two of the three items, and each individual item, the first, second, or third item.

[0046] The expression of the first element, the second element "and / or" the third element should be understood to cover one of the first element, the second element, and the third element and any and all combinations of the first element, the second element, and the third element. For example, A, B, and / or C may mean: only A; only B; only C; any one or some combination of A, B, and C; or all of A, B, and C. In addition, the expression "element A / element B" may be understood as element A and / or element B.

[0047] In one or more embodiments, unless otherwise stated, for convenience, the terms "between" and "among" may be simply used interchangeably. For example, the expression "between a plurality of elements" may be understood as among a plurality of elements. In another example, the expression "among a plurality of elements" may be understood as between a plurality of elements. In one or more examples, the number of elements may be two. In one or more examples, the number of elements may be more than two.

[0048] In one or more embodiments, unless otherwise specified, for convenience, the phrases "each other" and "mutually" may be used interchangeably. For example, the expression "different from each other" may be understood as different from each other. In another example, the expression "different from each other" may be understood as different from each other. In one or more examples, the number of elements involved in the foregoing statements may be two. In one or more examples, the number of elements involved in the foregoing statements may be more than two.

[0049] The features of the various embodiments of the present disclosure may be partially or entirely connected or combined with each other, and may be technically operated, linked or driven together in various ways. The embodiments of the present disclosure may be implemented or executed independently of each other, or may be implemented or executed together in a mutually dependent or related relationship. In one or more embodiments, the components of each device according to the various embodiments of the present disclosure may be operably connected and configured.

[0050] Unless otherwise defined, the terms (including technical and scientific terms) used herein have the same meaning as those commonly understood by ordinary technicians in the field to which the embodiments belong. It should also be understood that terms such as those defined in general dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant field, for example, and should not be interpreted in an idealized or overly formal sense, unless otherwise explicitly defined herein.

[0051] In the following description, various exemplary embodiments of the present disclosure are described in detail with reference to the accompanying drawings. With respect to the reference numerals of the elements of each drawing, the same elements may be shown in other drawings, and the same reference numerals may refer to the same elements, unless otherwise specified. In addition, for the convenience of description, the scale, size, size and thickness of each element shown in the drawings may be different from the actual scale, size, size and thickness, and therefore, the embodiments of the present disclosure are not limited to the scale, size, size and thickness shown in the drawings.

[0052] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0053] The inventors of the present disclosure have developed a piezoelectric material, and have recognized that the following problems may occur when the developed piezoelectric material is actually applied.

[0054] Since PZT piezoelectric materials, which account for the vast majority of piezoelectric materials, cause environmental pollution problems, it is necessary to develop a lead-free piezoelectric material. Compared with PZT piezoelectric materials, lead-free piezoelectric materials have lower piezoelectric properties, so it is necessary to develop materials with high piezoelectric properties.

[0055] To solve this problem, the inventors have developed a piezoelectric material composition that is formed on the surface of a seed crystal by using a buffer material.

[0056] Figure 1 is a cross-sectional view showing a piezoelectric device according to one embodiment of the present disclosure. The cross-sectional view shows a piezoelectric device including a piezoelectric material composition manufactured by a TGG process. A template grain growth (TGG) process may be one such sintering method that adds a seed to a base material to perform a TGG process.

[0057] refer to Figure 1The piezoelectric device 20 according to one embodiment of the present disclosure may include a piezoelectric material composition 21 , a first electrode layer 22 , and a second electrode layer 23 .

[0058] The piezoelectric material composition 21 may be disposed between the first electrode layer 22 and the second electrode layer 23. The piezoelectric material composition 21 may include a plurality of crystal grains configured with the first material 21a, the second material 21b, and the third material 21c. Each of the plurality of crystal grains configured with the first material 21a, the second material 21b, and the third material 21c may be divided by a grain boundary GB.

[0059] For example, the piezoelectric material composition 21 may be expressed as the following Formula 1. It should be understood that the embodiments of the present application are not limited thereto.

[0060] [Formula 1]

[0061] 0.96(Na a K 1-a )(Nb b (T 1-b ))O 3 -(0.04-x)M A M B O 3 –x(Bi c Ag 1-c )M B O 3 +d mol%A+Y+Z,

[0062] Where, T is Sb, Ta or V, M A is Sr, Ba or Ca, M B is Zr, Hf, Ti or Sn, A is Fe 2 O 3 、Co 2 O 3 , Mn 2 O 3 、ZnO、GeO 2 , CuO or NiO, and 0.40≤a≤0.60, 0.90≤b≤1.00, 0.30≤c≤0.70, 0.00≤x≤0.04 and 0.00 <d≤1.00。

[0063] For example, the first material 21a may be a base material. For example, the first material 21a may be a material that does not include Y and Z in Formula 1. For example, the first material 21a may be expressed as Formula 2 below.

[0064] [Formula 2]

[0065] 0.96(Na a K 1-a )(Nbb (T 1-b ))O 3 -(0.04-x)M A M B O 3 –x(Bi c Ag 1-c )M B O 3 +d mol%A,

[0066] Where, T is Sb, Ta or V, M A is Sr, Ba or Ca, M B is Zr, Hf, Ti or Sn, A is Fe 2 O 3 、Co 2 O 3 , Mn 2 O 3 、ZnO、GeO 2 , CuO or NiO, and 0.40≤a≤0.60, 0.90≤b≤1.00, 0.30≤c≤0.70, 0.00≤x≤0.04 and 0.00 <d≤1.00。

[0067] The piezoelectric material composition 21 may include a plurality of crystal grains. Each of the plurality of crystal grains may be divided by a grain boundary GB. The piezoelectric material composition 21 may include Fe 2 O 3 、Co 2 O 3 , Mn 2 O 3 、ZnO、GeO 2 , CuO and NiO. For example, when the piezoelectric material composition 21 contains iron oxide (Fe 2 O 3 ),Fe 2 O 3 can be added to the piezoelectric material composition of Formula 1 at 0 mol% (mole percent) to 1 mol%. For example, Fe 2 O 3 may be added at 0.5 mol % to the piezoelectric material composition of Formula 1. Therefore, according to one embodiment of the present disclosure, sinterability may be further improved.

[0068] The piezoelectric material composition 21 may have a (001) crystal orientation and may have a random orientation direction. For example, the piezoelectric material composition 21 according to one embodiment of the present disclosure may include a plurality of first materials 21a. For example, the TGG process may adjust or control the growth orientation of the grains by adding seed crystals, so that the orientation direction of the randomly distributed grains is aligned with the orientation direction of the grains along one direction.

[0069] The grains of the first material 21a may be grown based on the crystal orientation of the second material 21b. For example, the aspect ratio of the second material 21b may be 5 to 20. For example, multiple first materials 21a may have the same or substantially the same crystal orientation. For example, multiple first materials 21a may have a (001) crystal orientation. For example, multiple first materials 21a may have a crystal structure grown in a (001) orientation. For example, the first material 21a according to one embodiment of the present disclosure may be configured to surround the second material 21b and the third material 21c. For example, the second material 21b and the third material 21c may have the same or substantially the same crystal orientation. The first material 21a according to one embodiment of the present disclosure may be obtained by referring to the following Figure 3 and Figure 4 The method for preparing the base material is described.

[0070] The second material 21b may be formed in the first material 21a. The second material 21b may be surrounded by the first material 21a. For example, the second material 21b may be surrounded by the first material 21a so that the third material 21c is interposed between the second material 21b and the first material 21a. For example, the second material 21b may be surrounded by the third material 21c, and the third material 21c may be surrounded by the first material 21a.

[0071] The second material 21b may be disposed at the central portion of the first material 21a. In other words, the second material 21b is disposed in the central portion of each of the plurality of grains. For example, the central portion may not correspond mathematically exactly to the center (or middle) of the first material 21a having a certain volume, but may be a certain area including the center (or middle) of the first material 21a having a certain volume. For example, the central portion may be an area extending from the center of the first material 21a in the first material 21a having a certain volume. Therefore, in one embodiment of the present disclosure, even if the second material 21b is disposed at a position deviating from the center (or middle) of the first material 21a, this may also be within the scope of the present disclosure. For example, the second material 21b may be disposed in each of the plurality of first materials 21a, and in grain orientation growth, the second material 21b may be disposed close to the grain boundary GB which is the boundary between the plurality of first materials 21a.

[0072] The second material 21b according to one embodiment of the present disclosure may be a seed material. For example, the second material 21b may be Y in Formula 1. For example, Y as the second material 21b may include NaNbO 3 、BaTiO 3 、SrTiO 3 and(Bi 0.5 Na 0.5)TiO 3 One of, but the embodiments of the present disclosure are not limited thereto. For example, the second material 21b may be added to the piezoelectric material composition of Formula 1 at 2 mol% to 4 mol%. For example, the second material 21b may be used as a template so that the first material 21a grows on the crystal orientation of the second material 21b during the sintering process. For example, the first material 21a may be sintered based on the crystal orientation of the second material 21b. Therefore, the crystal orientations of the plurality of first materials 21a may be oriented to be the same or substantially the same orientation. The second material 21b according to one embodiment of the present disclosure may be obtained by referring to the following Figure 3 and Figure 5 The method for preparing the seed material is described.

[0073] The third material 21c may be formed in the first material 21a. The third material 21c may be surrounded by the first material 21a. The third material 21c may surround the second material 21b, and the first material 21a may surround the third material 21c. The third material 21c may surround all surfaces of the second material 21b. The third material 21c may cover the entire surface of the second material 21b. The third material 21c may be configured between the first material 21a and the second material 21b. For example, the third material 21c may be provided at each of the plurality of first materials 21a together with the second material 21b, and in the crystal orientation growth, the third material 21c may be configured to be adjacent to the grain boundary GB which is the boundary between the plurality of first materials 21a.

[0074] For example, the third material 21c may be Z in Formula 1. For example, Z as the third material 21c may include NaNbO 3 、BaTiO 3 and BiFeO 3 For example, the third material 21c may be added to the second material 21b in a range of 4 vol% to 8 vol%. For example, the thickness of the third material 21c may be in a range of 50 nm to 150 nm, but the embodiments of the present disclosure are not limited thereto.

[0075] According to an embodiment of the present disclosure, the third material 21c can act as a buffer between the first material 21a and the second material 21b. For example, during the sintering process of the piezoelectric material composition, the third material 21c can act as a buffer, making it easy for the first material 21a to bond to the second material 21b.

[0076] Therefore, in the embodiment of the present disclosure, since the third material 21c is disposed between the first material 21a and the second material 21b, stress and defects between the first material 21a and the second material 21b can be alleviated, and the reliability of the piezoelectric material composition can be improved. Figure 5 In the described method of preparing the seed material, the third material 21 c according to the embodiment of the present disclosure may be prepared by the steps of weighing the third material 21 c and coating (or forming) the third material 21 c.

[0077] The first electrode layer 22 and the second electrode layer 23 may be disposed facing each other so that the piezoelectric material composition 21 is located therebetween. For example, the first electrode layer 22 may be disposed at the first surface (or lower surface) of the piezoelectric material composition 21, and the second electrode layer 23 may be disposed at the second surface (or upper surface) of the piezoelectric material composition 21. The piezoelectric material composition 21 according to one embodiment of the present disclosure may be configured as a piezoelectric device 20 by disposing the first electrode layer 22 and the second electrode layer 23 at the first surface (or lower surface) and the second surface (or upper surface), respectively.

[0078] According to one embodiment of the present disclosure, since a piezoelectric material composition does not include lead (Pb) and has high piezoelectric characteristics, a piezoelectric device and a display apparatus each including the piezoelectric material composition may be driven with a low driving voltage.

[0079] In addition, according to the embodiments of the present disclosure, since the piezoelectric material composition does not contain lead, production limiting materials can be reduced and replacement of harmful materials can be achieved, so that an environmentally friendly piezoelectric material composition and a piezoelectric device including the same can be provided.

[0080] Furthermore, according to the embodiments of the present disclosure, since the buffer material is coated on the surface of the seed crystal or forms the surface of the seed crystal, a piezoelectric material composition can be provided for minimizing the interfacial defects between the base material and the seed crystal.

[0081] Figure 2A and Figure 2B Schematic diagram showing an interface between a seed crystal and a base material of a piezoelectric device according to a comparative example and an embodiment of the present disclosure. Figure 2A An interface between a seed crystal and a base material of a piezoelectric device according to a comparative example is shown, and relates to a piezoelectric device that does not include a third material. Figure 2B According to the reference Figure 1The present invention relates to an interface between a seed crystal and a base material of a piezoelectric device of an embodiment of the present disclosure, and relates to a piezoelectric device configured with a third material surrounding a second material. Therefore, hereinafter, the same reference numerals refer to the same elements, and the same elements will be briefly described or omitted.

[0082] refer to Figure 2A , the piezoelectric device according to the comparative example may include a piezoelectric material composition 11, and the piezoelectric material composition 11 may include a first material 11a and a second material 11b. In order to perform the TGG process, in the case where the piezoelectric material composition is configured with a second material 11b that does not react with the first material 11a, there may be a difference between the lattice constant of the matrix material of the piezoelectric material composition and the lattice constant of the seed crystal, and therefore, during the execution of the TGG process, dangling bonds may appear between the interface of the matrix material and the seed crystal. A dangling bond may be a state in which part of the bonds in the atoms or bonding parts of a crystal plane are cut off due to coordination unsaturation. For example, lattice stress may occur in the C region where dangling bonds occur. Lattice stress may be stress generated due to the difference in lattice size of each of the first material 11a and the second material 11b at the atomic bonding layer interface between the first material 11a and the second material 11b.

[0083] Therefore, in the piezoelectric material composition according to the comparative example, since lattice stress is concentrated at the interface between the base material and the seed crystal, bonding force is reduced and interface defects occur between the base material and the seed crystal, and thus piezoelectric characteristics of the piezoelectric material composition are deteriorated.

[0084] refer to Figure 2B , a piezoelectric device according to an embodiment of the present disclosure may include a piezoelectric material composition 21, and the piezoelectric material composition 21 may include a first material 21a, a second material 21b, and a third material 21c. For example, the second material 21b may include a seed material. For example, the third material 21c may include a buffer material. For example, the third material 21c may be coated (or formed) on the surface of the seed including the second material 21b. For example, the third material 21c may surround the second material 21b. For example, the third material 21c may surround the entire surface of the second material 21b.

[0085] According to one embodiment of the present disclosure, the third material 21c may be configured between the first material 21a and the second material 21b, and may function as a buffer. For example, the second material 21b and the third material 21c may be bonded to each other by atom units in region A. For example, the first material 21a and the third material 21c may be bonded to each other by atom units in region B. For example, the third material 21c may be bonded to each of the first material 21a and the second material 21b by atom units, and may function as a buffer that reduces the lattice stress of the first material 21a and the second material 21b.

[0086] According to an embodiment of the present disclosure, the third material 21c can alleviate the stress generation caused by the size difference between the first material 21a and the second material 21b at the atomic bonding layer interface between the first material 21a and the second material 21b. The third material 21c can alleviate the generation of stress, so the orientation characteristics of the piezoelectric material composition can be enhanced, and the degradation of the piezoelectric material composition can be alleviated.

[0087] Therefore, in the embodiment of the present disclosure, since the third material 21c is disposed between the first material 21a and the second material 21b, the lattice stress and defects of the piezoelectric material composition can be reduced. Therefore, the embodiment of the present disclosure can enhance the orientation characteristics, piezoelectric characteristics and reliability of the piezoelectric material composition.

[0088] According to an embodiment of the present disclosure, the second material 21b and the third material 21c may include different materials. For example, in the process of sintering the piezoelectric material composition, a plurality of second materials 21b may be respectively arranged at a plurality of first materials 21a. For example, a first material 21a and a second material 21b may form a grain having the same or substantially the same crystal orientation. In this case, the grains of the piezoelectric material composition may grow directionally, and therefore, each of the plurality of second materials 21b may be configured adjacent to a grain boundary GB as a boundary between the plurality of first materials 21a. For example, in the process of sintering the piezoelectric material composition, the second material 21b may be moved adjacent to the grain boundary GB, and therefore, a void may be formed at a position where the second material 21b was previously arranged. For example, the voids appearing in the piezoelectric material composition may cause the inhomogeneity of the composition and may reduce the relative density of the piezoelectric material composition. Therefore, the piezoelectric properties and reliability of the piezoelectric material composition may be reduced.

[0089] According to an embodiment of the present disclosure, since the second material 21b and the third material 21c include different materials, during the sintering process of the piezoelectric material composition, the voids in the piezoelectric material composition can be minimized by limiting the movement of the second material 21b. For example, since the second material 21b and the third material 21c include different materials and the third material 21c surrounds the second material 21b, a portion of the second material 21b can remain stationary during the sintering process.

[0090] Therefore, the embodiments of the present disclosure can reduce voids of the piezoelectric material composition and can increase relative density. Therefore, in the embodiments of the present disclosure, the piezoelectric characteristics and reliability of the piezoelectric material composition can be enhanced.

[0091] According to the embodiments of the present disclosure, although the RTGG process (reactive TGG process) is adopted, the formation of voids can be reduced, and the piezoelectric characteristics and orientation characteristics of the piezoelectric material composition can be enhanced.

[0092] Figure 3 Schematic diagram showing a method for manufacturing a piezoelectric device according to an embodiment of the present disclosure. Figure 1 and the method of the piezoelectric material composition described in FIG. 2 .

[0093] See also Figure 3 According to an embodiment of the present disclosure, a method for manufacturing a piezoelectric device S100 may include a step S110 of preparing a seed material and a matrix material of a piezoelectric material composition, a step S120 of mixing the matrix material with the seed material to prepare a slurry, a step S130 of molding the slurry to prepare a molded element, a step S140 of sintering the molded element to prepare a sintered material, and a step S150 of forming an electrode in the sintered piezoelectric material composition. The sintered piezoelectric material composition may be represented as described above with reference to Figure 1 Described in the following formula 1.

[0094] [Formula 1]

[0095] 0.96(Na a K 1-a )(Nb b (T 1-b ))O 3 -(0.04-x)M A M B O 3 –x(Bi c Ag 1-c )M B O 3 +d mol%A+Y+Z,

[0096] Where, T is Sb, Ta or V, M A is Sr, Ba or Ca, M B is Zr, Hf, Ti or Sn, A is Fe 2 O 3 、Co 2 O 3 , Mn 2 O 3 、ZnO、GeO 2 , CuO or NiO, and 0.40≤a≤0.60, 0.90≤b≤1.00, 0.30≤c≤0.70, 0.00≤x≤0.04, and 0.00 <d≤1.00。

[0097] For example, in Formula 1, Y may be a seed material, and Z may be a buffer material. For example, the base material may be a material other than the seed material and the buffer material in Formula 1, and may be prepared by the method S10 for preparing a base material described below. The composition of the seed material may be NaNbO 3 、BaTiO 3 、SrTiO 3 or(Bi 0.5 Na 0.5 )TiO 3 , and the size of the seed material may be 5 μm or more, but the embodiments of the present disclosure are not limited thereto. The aspect ratio of the seed material may be in the range of 5 to 20 or 10 to 15, but the embodiments of the present disclosure are not limited thereto. The seed may be prepared by the method S20 for manufacturing the seed described below. For example, the seed may be added to the entire material composition of Formula 1 at 2 mol% to 4 mol%, but the embodiments of the present disclosure are not limited thereto.

[0098] For example, the composition of the buffer material may be NaNbO 3 、BaTiO 3 or BiFeO 3 composition, and the buffer material may surround the surface of the seed crystal. For example, the buffer material may surround the surface of the seed crystal and may be used as a buffer portion to reduce defects between the base material and the seed crystal. For example, the thickness of the buffer portion configured by the buffer material may be in the range of 50nm to 150nm, but the embodiments of the present disclosure are not limited thereto. For example, the buffer material may be added to the seed crystal material of Formula 1 at 4vol% to 8vol%, but the embodiments of the present disclosure are not limited thereto. For example, the buffer material may be prepared by the steps of weighing the buffer material in the method S20 for manufacturing the seed crystal described below and coating (or forming) the buffer material on the seed crystal. Therefore, the step S110 of preparing the base material and the seed crystal material of the piezoelectric material composition may be completed.

[0099] Subsequently, method S100 may include mixing the base material with the seed material to prepare slurry S120. Mixing the base material with the seed material to prepare slurry S120 may include preparing slurry including the base material and mixing the seed material coated (or formed) with the buffer material on the base material.

[0100] The step of preparing a slurry comprising a matrix material may be similar to the step described above with reference to Figure 1 The base material of the composition of Formula 2 described above is added with a suitable amount of dispersant and solvent. For example, the solvent may include one or more of ethanol, methanol, isopropanol, MEK, toluene and distilled water, but the embodiments of the present disclosure are not limited thereto. By adding a suitable amount of dispersant and solvent to the base material, a slurry can be prepared in which the base material is fully dispersed in the solvent.

[0101] According to one embodiment of the present disclosure, the dispersant can reduce the viscosity of the slurry containing the matrix material and can be used to disperse the first material 21a and the second material 21b in the solvent. For example, the step of preparing the slurry can be prepared by performing the grinding step four times, but the embodiment of the present disclosure is not limited to the number of grinding steps.

[0102] For example, primary slurry grinding can be performed by adding an appropriate amount of solvent and dispersant to the prepared matrix material slurry. Primary slurry grinding can be to disperse the matrix powder. Primary slurry grinding can be ball milling, but the embodiments of the present disclosure are not limited thereto. For example, primary slurry grinding can be performed at a range of 100rpm to 150rpm for 24 hours to 72 hours, but the embodiments of the present disclosure are not limited thereto. For example, primary slurry grinding can be performed at a range of 100rpm to 150rpm for 12 hours to 16 hours, but the embodiments of the present disclosure are not limited thereto. For example, primary slurry grinding can be wet grinding, but the embodiments of the present disclosure are not limited thereto. For example, when the matrix powder, solvent and dispersant are mixed with nylon or high-density polyethylene (HDPE) and ZrO 2 After the balls (eg, YSZ balls) are loaded together into a Nalgene bottle, the primary slurry grinding may be performed at a range of 100 rpm to 150 rpm for 12 to 16 hours, but embodiments of the present disclosure are not limited thereto.

[0103] 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 embodiments of the present disclosure are not limited thereto. For example, the secondary slurry grinding may be performed at a range of 100 rpm to 150 rpm for 6 hours to 24 hours, but the embodiments of the present disclosure are not limited thereto. For example, the secondary slurry grinding may be wet grinding, but the embodiments of the present disclosure are not limited thereto. For example, after the binder and the plasticizer are added to the primary slurry grinding, the secondary slurry grinding may be performed with ZrO 2 The balls (eg, YSZ balls) are performed together at a range of 100 rpm to 150 rpm for 6 hours to 25 hours, but the embodiments of the present disclosure are not limited thereto.

[0104] The adhesive (or bonding agent) can provide stiffness, flexibility, ductility, durability, toughness and smoothness of the molding element. The adhesive can include at least one of PVB resin, PVA and PEG, but the embodiments of the present disclosure are not limited thereto, and adhesives known to those skilled in the art of piezoelectric material compositions can be used.

[0105] A plasticizer may be added to provide elasticity and plasticity to the molded element. The plasticizer may include at least one of phthalate plasticizers, adipate plasticizers, phosphate plasticizers, polyether plasticizers, and polyester plasticizers, and plasticizer materials known to those skilled in the art of piezoelectric material compositions may be used.

[0106] The step of mixing the seed material coated with the buffer material on the base material may be mixing the seed material coated with the buffer material on the slurry containing the base material prepared in the previous step, and may be performed by tertiary slurry grinding and quaternary slurry grinding. For example, tertiary slurry grinding may separate and discharge the slurry from the balls, add seed crystals according to the proportion of the base powder contained in the discharged slurry at dmol%, and fill the slurry into a Nalgene bottle without balls, and thus, tertiary slurry grinding may be performed at a range of 20 rpm to 30 rpm for 3 hours to 6 hours, but the embodiments of the present disclosure are not limited thereto. For example, the grinding process may be performed for a shorter time at a speed lower than that of primary slurry grinding and secondary slurry grinding. For example, tertiary slurry grinding may be performed by removing ZrO 2 The balls are then seeded and the rotation is performed at a range of 20 rpm to 30 rpm for 3 to 6 hours, but the embodiments of the present disclosure are not limited thereto.

[0107] For example, four-stage slurry grinding can be performed after three-stage slurry grinding. Four-stage slurry grinding can be performed by performing three planetary millings in the range of 500rpm to 2,000rpm, each for 10 minutes, but the embodiments of the present disclosure are not limited thereto. For example, four-stage slurry grinding can be to uniformly disperse the seed material. Therefore, according to a method for manufacturing a piezoelectric material composition of an embodiment of the present disclosure, the seed material coated (or formed) with a buffer material can be mixed on the base material so as to be uniformly distributed.

[0108] One embodiment of the present disclosure may further include an aging step after the four-stage slurry grinding and a degassing step of removing bubbles and gas.

[0109] The degassing step may be to adjust the slurry to have a suitable viscosity for the molding process and to remove bubbles remaining in the slurry in the step of molding the piezoelectric material described below. For example, the degassing step may be to adjust the slurry to have a viscosity of 1,000 cPs to 3,000 cPs (centipoise), 1,500 cPs to 2,500 cPs or 3,000 cPs at room temperature by a vacuum agitator, but the embodiments of the present disclosure are not limited thereto. For example, the degassing step may be to adjust the slurry to have a viscosity of 1,700 cPs to 2,400 cPs or 2,000 cPs (centipoise) by a vacuum agitator at room temperature, but the embodiments of the present disclosure are not limited thereto. Therefore, bubbles in the slurry can be removed, and the viscosity can be adjusted by volatilizing the solvent.

[0110] The aging step may be to adjust the temperature to room temperature again because the slurry is cooled when the solvent evaporates in the degassing step. For example, in the aging step, a short-time stirring may be performed by a stirrer at a low speed of about 10 rpm, but the embodiments of the present disclosure are not limited thereto. Therefore, the piezoelectric material in the form of a slurry may be configured.

[0111] Subsequently, step S130 of molding (or compression molding) the slurry to prepare a molded element may include manufacturing a molded element having a certain volume and shape through the slurry (or piezoelectric material), wherein the matrix material and the seed material prepared in step S120 are mixed with each other in the slurry (or piezoelectric material).

[0112] For example, the step of molding the slurry (or piezoelectric material) to prepare a molded element may include casting the piezoelectric material, performing primary molding on the cast piezoelectric material, and performing secondary molding on the primary molded piezoelectric material.

[0113] The casting step may be casting the slurry, wherein the base material prepared in the previous step is mixed with the seed material by a casting device (or scraper). For example, when casting is performed at a temperature of 90°C or higher, the manufactured sheet may crack or defects such as voids may occur due to the rapid evaporation rate of the solvent. Therefore, the temperature condition of each stage of the casting device may be 30°C to below 90°C. For example, the casting step may be a process in which the degassed secondary slurry is placed in a slurry chamber, passed through a doctor blade (or comma blade) adjusted to a certain height at a certain speed (e.g., a speed of 0.5 mm / min), and formed into a green sheet (or molded sheet) via a temperature cycle. The temperature cycle may include 40°C, 60°C, and 80°C, but embodiments of the present disclosure are not limited thereto.

[0114] The cast piezoelectric materials (or sheets) may be stacked (or laminated) and then heated at 55° C. to 75° C. at 2,500 psi / cm 2 Up to 4,000psi / cm 2 For example, the cast piezoelectric material (or sheet) may be stacked and then pressed at 60°C at 3,000 psi / cm 2 For example, lamination (or stacking) can be stacking the prepared green sheets, and the green sheets can be pressed at a pressure of 100 MPa / cm 2 pressure stack, but the embodiments of the present disclosure are not limited thereto.

[0115] The step of primary molding of the cast piezoelectric material can be performed by WIP, and the step of secondary molding of the cast piezoelectric material can be performed by cold isostatic pressing (CIP), and the step of secondary molding of the cast piezoelectric material can be used to increase the density of the sintered material in the sintering step described below. In the piezoelectric material composition according to one embodiment of the present disclosure, WIP can be performed in the case of a molded element prepared based on stacking and lamination such as casting. For example, by WIP, the stacked piezoelectric material can be 3,000 psi / cm at 60°C. 2 The pressure of 1000 ℃ or higher is maintained and pressed for 10 minutes, but the embodiments of the present disclosure are not limited thereto. The WIP may be hot isostatic pressing, but the embodiments of the present disclosure are not limited thereto.

[0116] The step S130 of molding the piezoelectric material may further include a degreasing step after the primary molding. The degreasing step may be to bake an organic solvent such as a binder, a plasticizer or a dispersant before sintering the stacked molded sheets that complete the WIP. The degreasing step may be to remove the solvent or the organic material. The degreasing step may maintain the molded element in a furnace at a temperature range of 250° C. to 600° C. for 24 to 72 hours, and then the molded element may be cooled to room temperature. For example, in the degreasing step, the temperature and holding time of the furnace may be set according to the type of dispersant, binder and plasticizer used.

[0117] The step S130 of molding the piezoelectric material may include performing secondary molding after the degreasing step. For example, the secondary molding step may be performed by CIP. For example, the secondary molding step may be performed at room temperature, and the piezoelectric material may be kept at 28,000 psi to 30,000 psi for 8 minutes to 12 minutes, but the embodiments of the present disclosure are not limited thereto. For example, the secondary molding step may be performed at room temperature, and the piezoelectric material may be kept at 29,000 psi for 10 minutes, but the embodiments of the present disclosure are not limited thereto.

[0118] Subsequently, the step S140 of sintering the molded element to prepare a sintered material may be performed in a temperature cycle, and then may be cooled. For example, the sintering temperature may be in the range of 1,010° C. to 1,110° C., but the embodiments of the present disclosure are not limited thereto. For example, the sintering maintenance time may be 2 hours to 8 hours, but the embodiments of the present disclosure are not limited thereto.

[0119] Subsequently, the step S150 of forming an electrode in the sintered material may form an electrode on a first surface of the sintered material of the piezoelectric material and a second surface of the sintered material of the piezoelectric material, the sintered material of the piezoelectric material being prepared in the previous step, the second surface being opposite to the first surface. For example, the second surface of the sintered material of the piezoelectric material may be different from the first surface, or may be opposite to the first surface of the sintered material of the piezoelectric material. For example, the electrode may contain a metal, for example, may be formed by coating a metal (e.g., Ag), but the embodiments of the present disclosure are not limited thereto, and the use of the electrode may not be limited to a general electrode. For example, an electrode may be formed in the sintered material, the temperature may be increased at a heating rate of 5°C / min, the electrode may be maintained at 600°C for 10 minutes, then cooled naturally at room temperature, and an electric field of 3kV / mm may be applied at a temperature of 20°C to 40°C for about 20 minutes, thereby performing a polarization (or polarization) process on the electrode. The step S350 of forming an electrode in the sintered material may include printing an electrode in a cast green sheet.

[0120] For example, a sintering process includes a step of performing sintering at a second sintering temperature of 1,090° C. for a long time (e.g., 10 hours) after reaching a very high first sintering temperature of 1,190° C. The sintering curve of such a sintering process may be relatively complex and may require a high first sintering temperature of 1,190° C. In contrast, a sintering method according to an embodiment of the present disclosure may include a primary sintering process of increasing the temperature to 400° C. and then maintaining the increased temperature for 30 minutes, and a secondary sintering process of increasing the temperature to 1,090° C. and then maintaining the increased temperature for 3 to 6 hours, and therefore, the sintering curve may be relatively simple, and based on increasing the temperature to 1,090° C. after performing sintering at 400° C., it may not be necessary to increase the sintering temperature each time.

[0121] Figure 4 Schematic diagram showing a method for manufacturing a base material of a piezoelectric material composition according to an embodiment of the present disclosure. Figure 3 A method for manufacturing a base material in a method for manufacturing a piezoelectric material composition is described.

[0122] refer to Figure 4 , a method S10 for manufacturing a matrix material of a TGG piezoelectric material composition according to an embodiment of the present disclosure may include a step S11 of weighing raw materials, a step S12 of mixing the weighed raw materials, a step S13 of calcining and synthesizing the mixed raw materials, and a step S14 of grinding the synthesized matrix material. The step S11 of weighing the raw materials may be performed independently of the manufacturing method, or may be omitted. For example, the method for manufacturing a matrix material according to one or more embodiments of the present disclosure may start with mixing raw materials having Formula 2. In the following description, the conditions (e.g., temperature, pressure, and time) based on the method for manufacturing a piezoelectric material composition may not limit the details of the present disclosure.

[0123] First, the step S11 of weighing the raw materials may weigh the raw materials based on a molar ratio to add an appropriate amount of solvent.

[0124] The base material according to one embodiment of the present disclosure may be expressed as Formula 2 below.

[0125] [Formula 2]

[0126] 0.96(Na a K 1-a )(Nb b (T 1-b ))O 3 -(0.04-x)M A M B O 3 –x(Bi c Ag1-c ) M B O 3 + d mol% A,

[0127] wherein T is Sb, Ta or V, M A is Sr, Ba or Ca, M B is Zr, Hf, Ti or Sn, and A is Fe 2 O 3 , Co 2 O 3 , Mn 2 O 3 , ZnO, GeO 2 , CuO or NiO, and 0.40 ≤ a ≤ 0.60, 0.90 ≤ b ≤ 1.00, 0.30 ≤ c ≤ 0.70, 0.00 ≤ x ≤ 0.04, and 0.00 < d ≤ 1.00. According to one embodiment of the present specification, the parent material satisfying Formula 2 may be (Na, K, Sr, Bi, Ag)(Nb, Sb, Zr)O 3 .

[0128] The raw materials for the matrix material satisfying Formula 2 may include sodium carbonate (Na 2 CO 3 ), potassium carbonate (K 2 CO 3 ), niobium oxide (Nb 2 O 5 ), antimony oxide (Sb 2 O 3 ), strontium carbonate (SrCO 3 ), zirconium oxide (ZrO 2 ), calcium carbonate (CaCO 3 ), barium carbonate (BaCO 3 ), hafnium oxide (HfO 2 ), titanium oxide (TiO 2 ), tin oxide (SnO 2 ), bismuth oxide (Bi 2 O 3 ), silver oxide (Ag 2 O) and iron oxide (Fe 2 O 3 ). However, the embodiments of the present disclosure are not limited thereto. For example, the raw materials may include oxides other than carbonates, including the corresponding positive ions (e.g., Na + , K + , Nb +5 , Sb +3 , Ca +2 , Sr +2 and Zr +4). For example, the step S11 of weighing the raw materials may be a process of weighing the raw materials based on the molar ratio of the composition to be synthesized, placing the weighed raw materials into a nylon jar, and then adding an appropriate amount of solvent (e.g., ethanol), but the embodiments of the present disclosure are not limited thereto.

[0129] The matrix material according to one embodiment of the present disclosure may include Fe 2 O 3 For example, Fe 2 O 3 It can be added in an amount of 1 mol% or less. For example, Fe 2 O 3 It can be added at 0.5 mol%. Therefore, according to one embodiment of the present disclosure, Fe 2 O 3 , thereby further improving the sintering properties of the piezoelectric material.

[0130] Subsequently, the step S12 of mixing the raw materials may be to mix and grind the weighed raw materials and a solvent (e.g., ethanol) by a ball milling process. For example, the ball milling process may put the weighed raw materials into a Nalgene bottle together with a YSZ ball and a solvent, and then the ball milling process may be performed at a range of 100 rpm to 150 rpm for 12 to 36 hours, but the embodiments of the present disclosure are not limited thereto.

[0131] One embodiment of the present disclosure may further include a drying step of separating the powder mixed with the solvent after the grinding step. Here, the drying step may separate and discharge the ground raw material from the ball, and then the ground base material may be placed in a tray, and the ground base material may be dried at a temperature of 90° C. to 100° C. For example, the drying may be performed for 3 hours, but the embodiments of the present disclosure are not limited thereto. Therefore, the ethanol mixed with the raw material may be removed.

[0132] Subsequently, one embodiment of the present disclosure may include a step S13 of calcining the raw materials. The step S13 of calcining the raw materials may be phase-synthesizing the raw materials that have been primarily mixed. The calcining step S13 may be finely grinding the dried compound with a mortar after the mixing is completed, placing the ground compound in an alumina crucible, increasing the temperature of the ground compound at a heating rate of 5°C / min in an electric furnace, calcining the compound at a temperature of 750°C to 850°C for 3 to 6 hours, and cooling or naturally cooling the calcined compound at room temperature (or normal temperature). For example, the calcination temperature may be 700°C to 900°C, and the holding time may be 1 to 6 hours, but the embodiments of the present disclosure are not limited thereto. Therefore, in one embodiment of the present disclosure, carbonates in the raw materials may be removed, and the raw materials may react uniformly to form a uniform perovskite phase.

[0133] Subsequently, the step S140 of grinding the calcined base material may be to pack the base material together with YSZ balls and a solvent (ethanol) into a Nalgene bottle and grind the base material into small particles through a ball milling process, but the embodiments of the present disclosure are not limited thereto.

[0134] In addition, the grinding step may further include a drying step of separating the powder mixed with the solvent after the grinding step. Here, the drying step may put the ground base material into a tray, and may fully dry the ground base material at a temperature of 100° C. For example, the drying may be performed for 3 hours, but the embodiments of the present disclosure are not limited thereto.

[0135] In addition, according to an embodiment of the present disclosure, the step S14 of grinding the synthesized matrix material may further include screening the material.

[0136] The screening step may be filtering out the dry powder finely ground by the mortar with a 40-mesh screen to produce a powder including particles of a certain size or smaller. The size of the powder passing through the 40-mesh screen may be 400 μm or smaller, but the embodiments of the present disclosure are not limited thereto.

[0137] Figure 5 Schematic diagram showing a method for manufacturing a seed material of a piezoelectric material composition according to an embodiment of the present disclosure. The schematic diagram may be represented in the above reference Figure 3 In the method for manufacturing a piezoelectric material composition described in the present invention, a method for manufacturing a seed crystal coated (or formed) with a buffer material is described. 3 Seed crystal) method.

[0138] refer to Figure 5 According to an embodiment of the present disclosure, the method S20 for manufacturing a seed material of a piezoelectric material composition may include a step S21 of primary weighing the seed material (or a second material), a step S22 of preparing a primary seed, a step S23 of performing a secondary weighing, a step S24 of preparing a secondary seed, a step S25 of weighing a buffer material (or a third material), and a step S26 of coating (or forming) a third material on the secondary seed.

[0139] First, the step S21 of initially weighing the seed material may be to weigh the primary seed material based on a molar ratio to add an appropriate amount of solvent.

[0140] Here, the molar ratio of the components to be synthesized in the primary seed crystal may be (Bi 2.5 Na 3.5 )Nb 5 O 16 Therefore, the primary seed crystal may be referred to as a "BNN seed crystal" hereinafter.

[0141] For example, in the step S21 of initially weighing the seed material, Na can be weighed according to the molar ratio of the components to be synthesized. 2 CO 3 , Nb 2 O 5 、Bi 2 O 3 and NaCl, and can be placed in a nylon tank, to which a suitable amount of solvent can then be added. For example, the solvent can be ethanol, but the embodiments of the present disclosure are not limited thereto.

[0142] In addition, during the primary weighing step, the Na 2 CO 3 , Nb 2 O 5 、Bi 2 O 3 and NaCl. For example, NaCl and Na 2 CO 3 , Nb 2 O 5 、Bi 2 O 3 The ratio of the oxides may be 1:1.5, but the embodiments of the present disclosure are not limited thereto.

[0143] The step S22 of preparing primary seed crystals may further include mixing the materials weighed out in the previous step, and performing phase synthesis on the mixed primary seed crystal materials.

[0144] For example, the mixed primary seed material may be mixed with a solvent, and the mixing and grinding may be continued for 12 hours by a ball milling process. Also, the step of mixing the primary seed may further include a drying step of separating the powder mixed with the solvent after the mixing and grinding steps. Here, the drying step may place the primary mixed base material in a tray, and the mixed base material may be fully dried at a temperature of 90° C. to 100° C., but the embodiments of the present disclosure are not limited thereto. For example, the drying may be performed for 3 hours, but the embodiments of the present disclosure are not limited thereto.

[0145] For example, the phase synthesis step may be to finely grind the compound with a mortar after mixing and drying the primary seed material, put the ground compound into an alumina crucible, increase the temperature of the ground compound at a heating rate of 5°C / min in an electric furnace, calcine the compound at 1,100°C to 1,175°C for 6 hours, and cool or naturally cool the calcined compound at room temperature. The BNN seed crystals that have completed calcination may have plate-like particles. Here, the step of phase synthesis of the primary seed material may be referred to as primary calcination. The phase synthesis step may be to synthesize BNN seeds as a precursor.

[0146] The step S22 of preparing primary seed crystals may further include washing the primary seed crystals that have completed calcination.

[0147] For example, the step of washing the primary seed crystals may be to wash and filter the primary seed crystals 2 to 10 times with distilled water at 80° C. or higher to remove NaCl on the primary seed crystal powder, but the embodiments of the present disclosure are not limited thereto. Drying may be performed in an oven at 90° C. for 3 hours after filtering, but the embodiments of the present disclosure are not limited thereto.

[0148] Subsequently, the secondary weighing step S23 may be to put in appropriate amounts of a solvent and a material containing Na for replacing Bi of the primary seed powder, and weigh out the solvent and the material based on a molar ratio of the composition.

[0149] Here, the molar ratio of the components of the secondary seed crystal may correspond to NaNbO 3 Therefore, hereinafter, the secondary seed crystal may be referred to as a "NN seed crystal".

[0150] For example, in the secondary weighing step, Na can be weighed out based on the molar ratio of the components to be synthesized. 2 CO 3 and NaCl, and can be placed in a beaker, and then a suitable amount of solvent can be added thereto. For example, the solvent can be ethanol, but the embodiments of the present disclosure are not limited thereto.

[0151] Subsequently, the step S24 of preparing the secondary seed crystals may include mixing the secondary weighed materials and performing a topochemical reaction.

[0152] For example, the step of mixing the secondary weighed materials may be performed through a stirring process, and may be performed at 80 rpm for 6 hours in a state where a magnetic bar is placed in a beaker, but the embodiments of the present disclosure are not limited thereto.

[0153] In addition, the step of preparing the secondary seed crystals may further include drying the mixed secondary weighed materials. Here, the drying step may place the compound in a tray and dry the compound at a temperature of 80° C. to 100° C. for 3 to 6 hours, but the embodiments of the present disclosure are not limited thereto.

[0154] In addition, the temperature may be increased from room temperature to 975° C. at a heating rate of 10° C. / min and may then be maintained for 6 hours, and then the mixed powder that has completed drying may be naturally cooled, but the embodiments of the present disclosure are not limited thereto.

[0155] For example, the step of performing a topochemical reaction may place the dried secondary seed material into a crucible and may be performed at 975° C. for 6 hours, but the embodiments of the present disclosure are not limited thereto. By performing a topochemical reaction, Bi in the primary seed may be replaced with Na. Here, the step of performing a topochemical reaction may be referred to as secondary calcination.

[0156] The step S24 of preparing the secondary seed crystal may further include cleaning the secondary seed crystal that has completed the topochemical reaction.

[0157] For example, the step of washing the secondary seed crystals may be performed by washing and filtering the secondary seed crystals 2 to 10 times with distilled water at 80° C. or higher to remove NaCl attached to the NN seed crystals, but the embodiments of the present disclosure are not limited thereto. The residual ions Na + and Cl-, and drying may be performed in an oven at 90° C. to 100° C. for 3 to 6 hours after filtering, but embodiments of the present disclosure are not limited thereto.

[0158] Furthermore, even after washing and filtering, acid treatment with nitric acid may be performed multiple times in order to remove Bi remaining in the NN seed crystals. 3+ Ions and Bi 2 O 3, followed by neutralization and washing with water. For example, nitric acid can be placed in a beaker, NN seed crystals can be placed, and shaking can be performed every 10 minutes. This can be repeated for 10 minutes to 2 hours, but the embodiments of the present disclosure are not limited thereto. For example, the residual bismuth material can be ionized by performing 2 to 3 acid treatments with nitric acid for 20 minutes each time, and then filtering can be performed.

[0159] In addition, in order to remove some residual nitric acid neutralization and Bi 3+ ions, can be washed once or twice with distilled water, and then filtered to remove residual ions Bi 3+ After filtering, drying may be performed in an oven at 90° C. to 100° C. for 3 to 6 hours. Thus, NN seed crystals may be prepared. In the embodiments of the present disclosure, for example, NaNbO 3 The seed crystal, however, the embodiments of the present disclosure are not limited thereto and may be BaTiO 3 、SrTiO 3 and(Bi 0.5 Na 0.5 )TiO 3 One of them.

[0160] One embodiment of the present disclosure may include a step S25 of weighing a buffer material (or a third material) and a step S26 of coating (or forming) the third material on a secondary seed. The step S25 of weighing the buffer material (or the third material) may be a step of weighing the raw material of the third material used as a buffer layer. The step S26 of coating (or forming) the third material on the secondary seed may be prepared by a liquid phase synthesis process. For example, the liquid phase synthesis process according to an embodiment of the present disclosure may be one of a hydrothermal synthesis process, a coprecipitation process, and a sol-gel process.

[0161] According to an embodiment of the present disclosure, the seed material (or the second material) may be different from the buffer material (or the third material). For example, the seed material according to an embodiment of the present disclosure may be NaNbO 3 or BaTiO 3 , and the buffer material can be NaNbO 3 、BaTiO 3 or BiFeO 3 Therefore, the seed crystal on which the buffer material according to the embodiment of the present disclosure is coated (or formed) may include a seed crystal on which BaTiO is coated (or formed). 3 NaNbO 3 Seed crystal, on which BaFeO is coated (or formed) 3NaNbO 3 Seed crystal, BaTiO coated (or formed) with NaNbO3 3 Seed crystal, and BiFeO coated (or formed) thereon 3 BaTiO 3 A type of seed crystal.

[0162] For example, when using NaNbO 3 In the case of a seed crystal, NaNbO is coated (or formed) thereon. 3 The buffer material of the seed can be BaTiO 3 or BiFeO 3 .

[0163] For example, 14.66 g of BaCl 2 ·2H 2 O, 3.78 g TiCl 4 , 4 mol KOH and 40 ml of deionized water were stirred at 200 rpm for 1 hour at room temperature in a 100 ml polytetrafluoroethylene reactor and can be mixed with 1.33 g of NaNbO 3 The seed crystals are mixed, and then the temperature is raised to 230°C at a heating rate of 2°C / min and maintained for 3 hours. The deionized water can be used for washing 3 to 5 times to prepare a BaTiO 3 NaNbO 3 Seed crystal. This process can be a hydrothermal synthesis process.

[0164] For example, Bi(NO 3 ) 3 ·5H 2 O and Fe(NO 3 ) 3 9H 2 O can be dissolved in deionized (DI) water at a concentration of 1:1, and then can be co-precipitated dropwise in a 4 molar KOH solution. 70 moles of the co-precipitated suspension and 2.33 g of NaNbO 3 The seed crystal is placed in a 100 ml polytetrafluoroethylene reactor, and then the temperature is raised to 210°C at a heating rate of 2°C / min, and the reaction is allowed to proceed for 5 hours, and the seed crystal can be washed 3 to 5 times with deionized water to prepare a BiFeO-coated (or formed) 3 NaNbO 3 Seed crystals. This process can be a co-precipitation process.

[0165] For example, in the use of BaTiO 3 In the case of a seed crystal, BaTiO is coated (or formed) thereon. 3The buffer material of the seed can be NaNbO 3 or BiFeO 3 .

[0166] For example, 8.4 mol of NaOH, 3 g of Nb 2 O 5 and 45 ml of deionized water were mixed in a 100 ml polytetrafluoroethylene reactor, and then stirred at 200 rpm for 1 hour at room temperature. 1.88 g of BaTiO 3 The seed crystal is then added, and the temperature is then raised to 210°C at a heating rate of 2°C / min, the reaction is performed for 24 hours, and the cleaning is performed 3 to 5 times with deionized water, thereby preparing a BaTiO 3 NaNbO 3 Seed crystal. This process can be a hydrothermal synthesis process.

[0167] For example, BiFeO is coated (or formed) thereon 3 NaNbO 3 The seed crystal can be obtained by 3 BaTiO is coated (or formed) on the seed crystal 3 Here, 3.0 g of NaNbO 3 Seed crystal.

[0168] As another example, the seed crystals on which the buffer material according to the embodiment of the present disclosure is coated (or formed) can be manufactured by a sol-gel process. For example, the sol-gel process can be a low-temperature synthesis process for manufacturing ceramic powders in a solution or a colloidal suspension. The sol-gel process can synthesize the desired material by hydrolyzing and condensing a metal salt or a metal oxide using an acid or a base. The sol-gel process can dry the gel generated by the reaction, and then the oxide with a hydroxyl group can be converted into the final oxide by calcining or sintering.

[0169] For example, according to the sol-gel process of an embodiment of the present disclosure, a precursor of a seed material may be added to an alcohol solvent at 2°C, heating may be performed at 50°C to 60°C for about 13 days, or heat treatment may be performed at 90°C to 100°C for about 6 hours to manufacture a nanostructure of the seed material, a buffer material may be added, and treatment may be performed at a temperature of 175°C to 200°C to manufacture a nanostructure of the seed material on which a buffer material is coated (or formed). However, the embodiments of the present disclosure are not limited thereto. Therefore, in an embodiment of the present disclosure, a seed on which a buffer material is coated (or formed) may be prepared.

[0170] Figure 6is a schematic diagram showing a vehicle-mounted sound device according to an embodiment of the present disclosure.

[0171] refer to Figure 6 The vehicle-mounted sound device according to one embodiment of the present disclosure may include a sound device 500. The sound device 500 may be provided or equipped in a vehicle so as to output a sound S toward an interior space IS of the vehicle 800.

[0172] The vehicle 800 may include an interior material (or interior material) 850. In the following description, for convenience of description, the "interior material 850" may be referred to as a "vehicle interior material 850".

[0173] The vehicle interior material 850 may include all parts configuring the interior of the vehicle 800, or may include all parts provided at the indoor space IS of the vehicle 800. For example, the vehicle interior material 850 may be an interior member or an interior trim member of the vehicle 800, but the embodiments of the present disclosure are not limited thereto.

[0174] The vehicle interior material 850 according to one embodiment of the present disclosure may be configured to be exposed at the interior or indoor space IS of the vehicle 800, in the interior or indoor space IS of the vehicle 800. For example, the vehicle interior material 850 may be configured to cover one surface (or inner surface) of at least one of the main frame (or vehicle body), the side frame (or side body), the door frame (or door body), the handle frame (or steering wheel hub), and the seat frame, the surface being exposed at the indoor space IS of the vehicle 800.

[0175] According to one embodiment of the present disclosure, the vehicle interior materials 850 may include an instrument panel, pillar interior materials (or pillar trim), floor interior materials (or floor carpet), roof interior materials (or ceiling), door interior materials (or door trim), handle interior materials (or steering wheel hub), seat interior materials, rear bag interior materials (or rear seat rack), overhead console (or interior lighting interior materials), rearview mirrors, glove boxes and sun visors, but the embodiments of the present disclosure are not limited thereto.

[0176] The vehicle interior material 850 according to one embodiment of the present disclosure may include one or more of metal, wood, rubber, plastic, glass, fiber, cloth, paper, mirror, leather and carbon, but the embodiment of the present disclosure is not limited thereto. The vehicle interior material 850 containing plastic material may be an injection molding material realized by an injection molding process using a thermosetting resin or a thermoplastic resin, but the embodiment of the present disclosure is not limited thereto. The vehicle interior material 850 containing fiber material may include one or more of synthetic fiber, carbon fiber (or aramid fiber) and natural fiber, but the embodiment of the present disclosure is not limited thereto. The vehicle interior material 850 containing fiber material may include a fabric sheet, a knitted sheet or a non-woven fabric, but the embodiment of the present disclosure is not limited thereto. For example, the vehicle interior material 850 containing fiber material or the outer surface member may be a fabric member, but the embodiment of the present disclosure is not limited thereto. For example, the paper may be cone paper. For example, the cone paper may be pulp or foam plastic, but the embodiment of the present disclosure is not limited thereto. The vehicle interior material 850 containing leather material may include natural leather or artificial leather, but the embodiment of the present disclosure is not limited thereto.

[0177] The vehicle interior material 850 according to an embodiment of the present disclosure may include one or more of a flat portion and a curved portion. For example, the structure of the vehicle interior material 850 may correspond to the structure of a corresponding vehicle structural material, or the structure of the vehicle interior material 850 may be different from the structure of the corresponding vehicle structural material.

[0178] According to one embodiment of the present disclosure, the sound device 500 may be provided at the vehicle interior material 850. The sound device 500 may vibrate the vehicle interior material 850 to generate the sound S based on the vibration of the vehicle interior material 850. For example, the sound device 500 may directly vibrate the vehicle interior material 850 to generate the sound S based on the vibration of the vehicle interior material 850.

[0179] For example, the sound device 500 may be configured to have the Figures 1 to 5 One of the piezoelectric devices of one or more embodiments of the present disclosure is described.

[0180] For example, the sound device 500 may be configured to vibrate the vehicle interior material 850 to output the sound S toward the interior or indoor space IS of the vehicle 800. Therefore, the vehicle interior material 850 may be used as a sound vibration plate. The vehicle interior material 850 may be a vibration plate, a sound vibration plate, or a sounding plate for outputting the sound S. For example, the size of the vehicle interior material 850 may be larger than the size of the sound device 500, but the embodiments of the present disclosure are not limited thereto.

[0181] For example, the sound device 500 can be set at one or more locations in the dashboard, pillar interior material, floor interior material, roof interior material, door interior material, handle interior material and seat interior material, or can be set at one or more locations in the rear bag interior material, overhead console, rearview mirror, glove box and sun visor.

[0182] The sound device 500 according to one embodiment of the present disclosure can vibrate the corresponding vehicle interior material 850 by at least one of the one or more sound devices 500 set at the vehicle interior material 850 to output realistic sound S and / or stereo (including multi-channel) toward the interior space IS of the vehicle 800.

[0183] Figure 7 is a perspective view of a display device according to an embodiment of the present disclosure. Figure 8 According to one embodiment of the present disclosure, Figure 7 A cross-sectional view taken along line II'.

[0184] See also Figure 7 and Figure 8 , a device according to one embodiment of the present disclosure may include a vibration member 100 and a piezoelectric device 200 .

[0185] The vibration member 100 may be configured to display an image. The piezoelectric device 200 may be disposed at a rear surface (or back side) of the vibration member 100. For example, the piezoelectric device 200 may be configured to vibrate the vibration member 100.

[0186] 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 vibration object, a display panel, a vibration plate, or a front member, but the embodiments of the present disclosure are not limited thereto.

[0187] For example, the vibration member 100 or the vibration object may include one or more of the following items: a display panel including pixels configured to display an image, a screen panel onto which an image is projected from a display device, a lighting panel, a signage panel, a vehicle interior material, a vehicle glass window, a vehicle exterior material, a building ceiling material, a building interior material, a building glass window, an aircraft interior material, an aircraft glass window, wood, plastic, glass, metal, cloth, fiber, paper, rubber, leather, and a mirror, but the embodiments of the present disclosure are not limited thereto.

[0188] In the following description, the vibration member 100 will be described as the display panel 100 .

[0189] 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. 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 electrowetting display panel, a flexible micro-light-emitting diode display panel, or a flexible quantum dot light-emitting display panel, but the embodiments of the present disclosure are not limited thereto.

[0190] The display panel 100 according to one embodiment of the present disclosure may include a display area AA (or an active area) for displaying an image according to driving a plurality of pixels. Also, the display panel 100 may further include a non-display area IA surrounding the display area AA, but the embodiments of the present disclosure are not limited thereto.

[0191] The piezoelectric device 200 may vibrate the display panel 100 at the rear surface of the display panel 100, thereby providing sound and / or tactile feedback to the user (or viewer) based on the vibration of the display panel 100. The piezoelectric device 200 may be implemented at the rear surface of the display panel 100 to directly vibrate the display panel 100.

[0192] As one embodiment of the present disclosure, the piezoelectric device 200 may vibrate according to a voice signal synchronized with an image displayed through the display panel 100 to vibrate the display panel 100. As another embodiment of the present disclosure, the piezoelectric device 200 may be disposed at the display panel 100, or may vibrate according to a tactile feedback signal (or a tactile feedback signal) synchronized with a user's touch applied to a touch panel (or a touch sensor layer) embedded in the display panel 100 to vibrate the display panel 100. Therefore, the display panel 100 may vibrate according to the vibration of the piezoelectric device 200 to provide at least one of sound and tactile feedback to the user (or viewer).

[0193] The piezoelectric device 200 according to one embodiment of the present disclosure may be implemented to have a size corresponding to the display area AA of the display panel 100. The size of the piezoelectric device 200 may be 0.9 to 1.1 times the size of the display area AA, but the embodiments of the present disclosure are not limited thereto. For example, the size of the piezoelectric device 200 may be the same as the size of the display area AA, or may be smaller than the size of the display area AA. For example, the size of the piezoelectric device 200 may be the same or nearly the same as the display area AA of the display panel 100, so that the piezoelectric device 200 may cover most of the area of ​​the display panel 100, and the vibration generated by the piezoelectric device 200 may vibrate the entire part of the display panel 100, thereby making the localization of the sound higher and improving the user's satisfaction. In addition, the contact area (or panel coverage) between the display panel 100 and the piezoelectric device 200 may be increased, so that the vibration area of ​​the display panel 100 may be increased, thereby improving the sound effect of the mid-low pitch vocal cords generated according to the vibration of the display panel 100. Furthermore, the piezoelectric device 200 applied to a large-sized display device can vibrate the entire display panel 100 having a large size (or a large area), and thus the localization of the sound based on the vibration of the display panel 100 can be further enhanced, thereby achieving an improved sound effect. Therefore, the piezoelectric device 200 according to an embodiment of the present disclosure can be disposed at the rear surface of the display panel 100 so as to fully vibrate the display panel 100 in the vertical (or front-to-back) direction, thereby outputting the desired sound to the front area in front of the device or the display device.

[0194] The piezoelectric device 200 according to one embodiment of the present disclosure may be implemented as a film type. Since the piezoelectric device 200 may be implemented as a film type, its thickness may be thinner than the display panel 100, so the thickness of the display device will not increase due to the arrangement of the piezoelectric device 200. For example, the piezoelectric device 200 may use the display panel 100 as a sound vibration plate. For example, the piezoelectric device 200 may be referred to as a sound generating module, a vibration generating 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 vibration plate, but the embodiments of the present disclosure are not limited thereto. As another embodiment of the present disclosure, the piezoelectric device 200 may not be disposed at the rear surface of the display panel 100, but may be applied to a vibrating object instead of the display panel. For example, the vibration object may 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 embodiments of the present disclosure are not limited thereto. For example, the non-display panel may 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 embodiments of the present disclosure are not limited thereto. In this case, the vibrating object may be applied as a vibration plate, and the piezoelectric device 200 may vibrate the vibrating object to output sound.

[0195] The piezoelectric device 200 according to one embodiment 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 .

[0196] According to one embodiment 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 adhesive layer.

[0197] 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 embodiments of the present disclosure are not limited thereto. For example, the adhesive layer of the connection member 210 may include an epoxy group, an acrylic group, a silicone group, or a polyurethane group, but the embodiments of the present disclosure are not limited thereto.

[0198] The display panel 100 according to one embodiment of the present disclosure may further include a support member 300 disposed at a rear surface of the display panel 100 .

[0199] 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 so that there is 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 a set structure. For example, the support member 300 may be a cover bottom, a plate bottom, a back cover, a base frame, a metal frame, a metal chassis, a chassis base, or an m chassis, etc., but the embodiments of the present disclosure are not limited thereto. Therefore, the support member 300 may be implemented as any type of frame or plate-like structure disposed at the rear surface of the display panel 100.

[0200] The apparatus according to an embodiment of the present disclosure may further include a middle frame 400 .

[0201] The middle frame 400 may be disposed between the rear periphery of the display panel 100 and the front periphery of the support member 300. The middle 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, respectively, and may surround one or more of the side surfaces of each of the display panel 100 and the support member 300. The middle frame 400 may configure a gap space GS between the display panel 100 and the support member 300. The middle frame 400 may be referred to as a middle chassis, a middle cover, a middle chassis, etc., but the embodiments of the present disclosure are not limited thereto.

[0202] The middle frame 400 according to the embodiment of the present disclosure may include a first support portion 410 and a second support portion 430 .

[0203] 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, so that a gap space GS may be configured 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 the 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 the second frame connection member 403. For example, the first support portion 410 may have a single picture frame structure having a quadrilateral shape, or may include a frame structure having a plurality of partition bar shapes, but the embodiments of the present disclosure are not limited thereto.

[0204] The second support portion 430 may be vertically coupled to the outer surface of the first support portion 410 in parallel with the thickness direction Z of the device. The second support portion 430 may surround one or more of the outer surface of the display panel 100 and the outer surface of the support member 300, thus protecting the outer surface of each of the display panel 100 and the support member 300. The first support portion 410 may extend from the inner surface of the second support portion 430 toward the gap space GS between the display panel 100 and the support member 300.

[0205] Fig. 9 is a diagram showing an embodiment according to the present disclosure Figure 7 Schematic diagram of a piezoelectric device.

[0206] See also Fig. 9 , the piezoelectric device 200 according to one embodiment of the present disclosure may include a vibration structure 230 .

[0207] The vibration structure 230 may include a piezoelectric device layer 231 , a first electrode portion 233 , and a second electrode portion 235 .

[0208] The vibration structure 230 may include a first electrode portion 233 disposed at a first surface of the piezoelectric device layer 231 and a second electrode portion 235 disposed at a second surface of the piezoelectric device layer 231 , the second surface being opposite to (or different from) the first surface.

[0209] The piezoelectric device layer 231 may include a first material layer 231a, a second material layer 231b, and a third material layer 231c. According to one embodiment of the present disclosure, the first material layer 231a may be configured to surround the second material layer 231b and the third material layer 231c. For example, the third material layer 231c may surround the second material layer 231b and may be configured between the first material layer 231a and the second material layer 231b. For example, the second material layer 231b may be surrounded by the third material layer 231c, and the third material layer 231c may be surrounded by the first material layer 231a. The third material layer 231c may surround all surfaces of the second material layer 231b. The third material layer 231c may be coated (or formed) to cover the entire surface of the second material layer 231b.

[0210] According to one embodiment of the present disclosure, one first material layer 231a and one second material layer 231b may be configured to have one grain having the same or substantially the same crystal direction, and a grain boundary GB may be formed at a portion of another first material layer 231a and a second material layer 231b of another adjacent grain configured to contact each other. In one or more embodiments of the present disclosure, the crystal direction is the +Z axis direction defined in the figure. However, the embodiments of the present disclosure are not limited thereto, and the crystal direction may also be various applicable directions.

[0211] Therefore, the third material layer 231c according to one embodiment of the present specification may be disposed between the first material layer 231a and the second material layer 231b, thereby reducing stress and defects between the first material layer 231a and the second material layer 231b and improving the reliability of the piezoelectric material composition.

[0212] According to one embodiment of the present disclosure, the grains of the first material layer 231a can grow based on the crystal direction of the second material layer 231b, and therefore, multiple first material layers 231a can have the same or substantially the same crystal direction, for example, can have a (001) crystal direction, but the embodiments of the present disclosure are not limited thereto.

[0213] According to one embodiment of the present disclosure, the first electrode portion 233 may be disposed at a first surface of the piezoelectric device layer 231. The second electrode portion 235 may be disposed at a second surface of the piezoelectric device layer 231, the second surface being opposite to (or different from) the first surface.

[0214] The first electrode portion 233 and the second electrode portion 235 may use metal electrodes, for example, silver electrodes, but the embodiments of the present disclosure are not limited thereto.

[0215] In addition, Fig. 9 , the vibration structure 230 is shown as a single layer, but may be configured as a stack of two or more layers based on the desired performance of the piezoelectric device.

[0216] The above-described embodiments of the vibration structure 230 are described as examples only. The vibration structure 230 according to an embodiment of the present disclosure is not limited to a specific structure or configuration of material layers, such as the number and / or position of material layers.

[0217] The piezoelectric device according to one embodiment of the present disclosure can be applied to (or included in) a vibration device (or sound device) set at the device. The device according to the embodiment of the present disclosure can be applied to mobile devices, video phones, smart watches, watch phones, wearable devices, foldable devices, rollable devices, bendable devices, flexible devices, bending devices, sliding devices, variable devices, electronic organizers, e-books, portable multimedia players (PMP), personal digital assistants (PDA), MP3 players, mobile medical devices, desktop personal computers (PC), laptop PCs, netbook computers, workstations, navigation devices, car navigation devices, car display devices, car devices, theater equipment, theater display equipment, televisions (TV), wallpaper display devices, signage devices, game consoles, laptops, monitors, cameras, camcorders, household appliances, etc. In addition, the vibration device according to some embodiments of the present disclosure can be applied to (or included in) an organic light-emitting lighting device or an inorganic light-emitting lighting device. In the case where the vibration device is applied to (or included in) a lighting device, the lighting device can be used as lighting and a speaker. Furthermore, in the case where the vibration device according to an embodiment of the present disclosure is applied to (or included in) a mobile device or the like, the vibration device may be used as one or more of a speaker, a receiver, or a haptic device, but the embodiment of the present disclosure is not limited thereto.

[0218] Described below are a piezoelectric material composition, a method of manufacturing the same, a piezoelectric device, and an apparatus including the piezoelectric device according to one or more embodiments of the present disclosure.

[0219] According to one or more embodiments of the present disclosure, a piezoelectric material composition may include a first material, a second material in the first material, and a third material between the first material and the second material. The first material, the second material, and the third material all do not contain lead. The third material is bonded to each of the first material and the second material, and acts as a buffer between the first material and the second material.

[0220] According to one or more embodiments of the present disclosure, the first material may surround the second material and the third material.

[0221] According to one or more embodiments of the present disclosure, the third material may surround the second material.

[0222] According to one or more embodiments of the present disclosure, the third material may cover the entire surface of the second material.

[0223] According to one or more embodiments of the present disclosure, the thickness of the third material may be in the range of 50 nm to 150 nm.

[0224] According to one or more embodiments of the present disclosure, the second material may be a seed material, and the third material may be a buffer material.

[0225] According to one or more embodiments of the present disclosure, the first material may include a plurality of grains oriented in a single (001) orientation, and the second material surrounded by the third material may be provided in each of the plurality of grains, and the plurality of grains may grow based on the crystal orientation of the second material.

[0226] According to one or more embodiments of the present disclosure, each of the plurality of grains may be divided by a grain boundary, and the second material may be provided at a central portion of each of the plurality of grains.

[0227] According to one or more embodiments of the present disclosure, the piezoelectric material composition may be represented by Formula 1:

[0228] [Formula 1]

[0229] 0.96(Na a K 1-a )(Nb b (T 1-b ))O 3 -(0.04-x)M A M B O 3 –x(Bi c Ag 1-c )M B O 3 +d mol%A+Y+Z,

[0230] Where, T is Sb, Ta or V, M A is Sr, Ba or Ca, M B is Zr, Hf, Ti or Sn, and A is Fe 2 O 3 、Co 2 O 3 , Mn 2 O 3 、ZnO、GeO 2 , CuO or NiO, 0.40≤a≤0.60, 0.90≤b≤1.00, 0.30≤c≤0.70, 0.00≤x≤0.04, and 0.00 <d≤1.00。

[0231] According to one or more embodiments of the present disclosure, the first material may be 0.96 (Na a K 1-a )(Nb b (T 1-b ))O 3-(0.04-x)M A M B O 3 –x(Bi c Ag 1-c )M B O 3 +d mol%A.

[0232] According to one or more embodiments of the present disclosure, the Y may be the second material, and the second material may include NaNbO 3 、BaTiO 3 、SrTiO 3 or(Bi 0.5 Na 0.5 )TiO 3 , and the second material is added to the piezoelectric material composition of Formula 1 at 2 mol % to 4 mol %.

[0233] According to one or more embodiments of the present disclosure, Z may be the third material, and the third material may include NaNbO 3 、BaTiO 3 or BiFeO 3 , and the third material is added to the second material at 4 vol % to 8 vol %.

[0234] According to one or more embodiments of the present disclosure, the second material and the third material may be configured with different materials.

[0235] According to one or more embodiments of the present disclosure, a method for manufacturing a piezoelectric material composition may include: mixing a matrix material with a seed material to prepare a slurry, wherein a buffer material is formed on the seed material; molding the slurry to prepare a green tape; and sintering the green tape to prepare a sintered object. The sintered object may include a first material, a second material in the first material, and a third material between the first material and the second material.

[0236] According to one or more embodiments of the present disclosure, the seed material on which the buffer material is formed can be prepared by the steps including: a step of performing primary weighing of the raw material of the second material; a step of preparing primary seed crystals; a step of performing secondary weighing based on the primary seed crystals; a step of preparing secondary seed crystals; a step of weighing the raw material of the third material; and a step of forming the third material on the secondary seed crystals.

[0237] According to one or more embodiments of the present disclosure, the step of forming the third material on the secondary seed crystal is performed by one of a hydrothermal synthesis process, a co-precipitation process, and a sol-gel process.

[0238] According to one or more embodiments of the present disclosure, a piezoelectric device may include: a piezoelectric device layer; a first electrode portion disposed at a first surface of the piezoelectric device layer; and a second electrode portion disposed at a second surface of the piezoelectric device layer different from the first surface. The piezoelectric device layer may include a piezoelectric material composition. The piezoelectric material composition may include a first material, a second material in the first material, and a third material between the first material and the second material.

[0239] According to one or more embodiments of the present disclosure, an apparatus may include a vibration member and a piezoelectric device. The piezoelectric device may include: a piezoelectric device layer; a first electrode portion disposed at a first surface of the piezoelectric device layer; and a second electrode portion disposed at a second surface of the piezoelectric device layer different from the first surface. The piezoelectric device may include a piezoelectric material composition. The piezoelectric material composition may include a first material, a second material in the first material, and a third material between the first material and the second material.

[0240] According to one or more embodiments of the present disclosure, the vibration member can output vibration or sound based on the vibration of the piezoelectric device. The vibration member may include a display panel having a plurality of pixels displaying an image, a screen panel projecting an image from a display device, a light-emitting diode lighting panel, an organic light-emitting lighting panel, an inorganic light-emitting lighting panel, a sign panel, an interior material of a vehicle device, an exterior material of a vehicle device, a glass window of a vehicle device, an interior material of a seat of a vehicle device, a ceiling material of a building, an interior material of a building, a glass window of a building, an interior material of an aircraft, and a glass window of an aircraft, or the vibration member may include one or more of wood, plastic, glass, metal, cloth, fiber, paper, rubber, leather, carbon, and a mirror.

[0241] The above-mentioned features, structures and effects of the present disclosure are included in at least one embodiment of the present disclosure, but are not limited to one embodiment. In addition, those skilled in the art can realize the features, structures and effects described in at least one embodiment of the present disclosure by combining or modifying other embodiments. Therefore, the contents related to combination and modification should be understood to be within the scope of the present disclosure.

[0242] It will be apparent to those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the scope of the present disclosure. Therefore, the present disclosure is intended to cover modifications and variations of the present disclosure that fall within the scope of the appended claims and their equivalents.

Claims

1. A piezoelectric material composition comprising: First material; a second material in the first material; and a third material between the first material and the second material, in, The first material, the second material, and the third material all contain no lead; and The third material is bonded to each of the first material and the second material, and functions as a buffer between the first material and the second material.

2. The piezoelectric material composition according to claim 1, wherein The first material surrounds the second material and the third material.

3. The piezoelectric material composition according to claim 1, wherein The third material surrounds the second material.

4. The piezoelectric material composition according to claim 1, wherein The third material covers the entire surface of the second material.

5. The piezoelectric material composition according to claim 4, wherein The thickness of the third material is in the range of 50 nm to 150 nm.

6. The piezoelectric material composition according to claim 1, wherein The second material is a seed material, and the third material is a buffer material.

7. The piezoelectric material composition according to claim 1, wherein The first material includes a plurality of grains oriented in a single orientation of (001), and the second material surrounded by the third material is disposed in each of the plurality of grains, and The plurality of grains grow based on a crystal orientation of the second material.

8. The piezoelectric material composition according to claim 7, wherein: Each of the plurality of crystal grains is divided by a grain boundary, and the second material is provided at a central portion of each of the plurality of crystal grains.

9. The piezoelectric material composition according to claim 1, wherein The piezoelectric material composition is represented by Formula 1, [Formula 1] 0.96(Na a K 1-a )(Nb b (T 1-b ))O3-(0.04-x)M A M B O3–x(Bi c Ag 1-c )M B O3+d mol%A+Y+Z, Where, T is Sb, Ta or V, M A is Sr, Ba or Ca, M B is Zr, Hf, Ti or Sn, and A is Fe2O3, Co2O3, Mn2O3, ZnO, GeO2, CuO or NiO, and 0.40≤a≤0.60, 0.90≤b≤1.00, 0.30≤c≤0.70, 0.00≤x≤0.04, and 0.00 <d≤1.00。 10. The piezoelectric material composition according to claim 9, wherein The first material is 0.96 (Na a K 1-a )(Nb b (T 1-b ))O3-(0.04-x)M A M B O3–x(Bi c Ag 1-c )M B O3+d mol%A.

11. The piezoelectric material composition according to claim 9, wherein The Y is the second material, and the second material includes NaNbO3, BaTiO3, SrTiO3 or (Bi 0.5 Na 0.5 )TiO3, and the second material is added to the piezoelectric material composition of Formula 1 at 2 mol % to 4 mol %.

12. The piezoelectric material composition according to claim 11, wherein The Z is the third material, the third material includes NaNbO 3 , BaTiO 3 , or BiFeO 3 , and the third material is added to the second material at 4 vol % to 8 vol %.

13. The piezoelectric material composition according to claim 12, wherein: The second material and the third material are configured with different materials.

14. A method for manufacturing a piezoelectric material composition, the method comprising: The step of mixing a base material with a seed material to prepare a slurry, wherein a buffer material is formed on the seed material; The step of shaping the slurry to prepare a green tape; and The step of sintering the green tape to prepare a sintered product, Wherein, the sintered product comprises the piezoelectric material composition according to any one of claims 1 to 13.

15. The method according to claim 14, wherein: The seed material on which the buffer material is formed is prepared by the steps comprising: The step of performing preliminary weighing on the raw materials of the second material; The step of preparing primary seed crystals; The step of performing secondary weighing based on the primary seed crystal; The step of preparing secondary seed crystals; A step of weighing the raw material of the third material; as well as The step of forming the third material on the secondary seed crystal.

16. The method according to claim 15, wherein: The step of forming the third material on the secondary seed crystal is performed by one of a hydrothermal synthesis process, a co-precipitation process, and a sol-gel process.

17. A piezoelectric device, comprising: Piezoelectric device layer; a first electrode portion disposed on a first surface of the piezoelectric device layer; as well as a second electrode portion provided at a second surface of the piezoelectric device layer different from the first surface, Wherein, the piezoelectric device layer comprises the piezoelectric material composition according to any one of claims 1 to 13.

18. An apparatus comprising: Vibrating components; as well as The piezoelectric device according to claim 17, wherein the piezoelectric device is configured to vibrate the vibration member.

19. The device according to claim 18, wherein: The vibration member outputs vibration or sound based on the vibration of the piezoelectric device, and The vibration component includes one or more of a display panel having multiple pixels for displaying an image, a screen panel onto 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 device, an exterior material of a vehicle device, a glass window of a vehicle device, an interior material of a seat of a vehicle device, a ceiling material of a building, an interior material of a building, a glass window of a building, an interior material of an aircraft, and a glass window of an aircraft, or the vibration component includes one or more of wood, plastic, glass, metal, cloth, fiber, paper, rubber, leather, carbon, and a mirror.

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