Piezoelectric actuator and method for manufacturing same

Abstract

A piezoelectric actuator is provided. An piezoelectric actuator according to an embodiment of the present invention comprises: one or more piezoelectric layers in which piezoelectric ceramic powder is sintered; and an electrode layer disposed on one surface or both surfaces of the piezoelectric layer. The piezoelectric ceramic powder includes a grown seed processed through a seed growth step. For a piezoelectric actuator including seeds, the vibration acceleration and D33 of a piezoelectric element are increased and thus, at the same number of stacked layers, high electrical characteristics can be obtained.

Description

Piezoelectric actuator and method for manufacturing the same

[0001] The present invention relates to a PNN-PZT (Lead Nickel Niobate-Lead Zirconate Titanate) series piezoelectric ceramic element, and more specifically, to a piezoelectric element comprising a seed composition capable of improving the characteristics of a PNN-PZT (Lead Nickel Niobate-Lead Zirconate Titanate) series piezoelectric ceramic element and a method for manufacturing the same.

[0002] Recently, products applying haptic technology are rapidly expanding across various industries.

[0003] Meanwhile, PNN-PZT series piezoelectric ceramic elements have high piezoelectric coefficients and electromechanical coupling coefficients, and are used in various fields such as mobile phone side key haptics, ultra-long distance ultrasonic sensors, actuators for 3D haptics, and directional speakers.

[0004] In addition, as the application of haptic technology to mobile phones has recently increased, there is a growing demand from consumers for more sophisticated and intuitive piezoelectric actuator-related technologies.

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

[0006] The present invention is proposed in consideration of the aforementioned conventional circumstances, and aims to provide a piezoelectric actuator in which a piezoelectric element with improved piezoelectric properties is applied by adding a composition to a PNN-PZT piezoelectric ceramic element.

[0007] To achieve the above objectives, a piezoelectric actuator according to a preferred embodiment of the present invention may include one or more piezoelectric layers sintered with piezoelectric ceramic powder; and electrodes disposed on one or both sides of the piezoelectric layers, and the piezoelectric ceramic powder may include culture seeds processed through a seed culture step.

[0008] The culture seed may contain BaTiO3.

[0009] The concentration of culture seeds in the piezoelectric ceramic powder can be 1.5 wt% to 2.5 wt%.

[0010] The culture seed can have a plate-like structure.

[0011] Piezoelectric ceramic powder may include PNN-PZT-based ceramics.

[0012] The composition of PNN-PZT series ceramics is 0.5Pb(Ni (1-X) Nb (X) )O3- 0.5Pb(Zr (1-y) Ti (y) )O3, and X and Y values ​​may be greater than 0 and less than 1.

[0013] The culture seed may include at least one of PbTiO3, LaNiO3, and BiFeO3.

[0014] A method for manufacturing a piezoelectric actuator may include a powder manufacturing step for manufacturing a first ceramic powder, a slurry manufacturing step for manufacturing a slurry, a seed culture step for manufacturing a culture seed using a seed and a slurry, and a casting step for manufacturing a piezoelectric ceramic powder by casting the first ceramic powder manufactured in the powder manufacturing step and the culture seed manufactured in the seed culture step.

[0015] A seed culture step for generating a culture seed may include a step of separating raw seed to obtain a first seed composed of particles of a set size, a step of adding the first seed to a slurry and milling or mixing to obtain a second seed, and a step of milling or mixing the second seed to obtain a culture seed.

[0016] The culture seed may contain BaTiO3.

[0017] The concentration of culture seeds in the piezoelectric ceramic powder can be 1.5 wt% to 2.5 wt%.

[0018] The culture seed can have a plate-like structure.

[0019] Piezoelectric ceramic powder may include PNN-PZT-based ceramics.

[0020] The composition of PNN-PZT series ceramics is 0.5Pb(Ni (1-X) Nb (X) )O3- 0.5Pb(Zr (1-y) Ti (y) )O3, and X and Y values ​​may be greater than 0 and less than 1.

[0021] The culture seed may include at least one of PbTiO3, LaNiO3, and BiFeO3.

[0022] The piezoelectric actuator of the present invention and the method for manufacturing the same have the effect of being able to exhibit excellent vibration acceleration and piezoelectric constant characteristics compared to the same number of layers by adding a seed composition to a PNN-PZT series piezoelectric ceramic element.

[0023] As a result, the number of layers can be reduced compared to existing products, which provides an advantage in price competition.

[0024] FIG. 1 is a conceptual diagram of a piezoelectric element according to one embodiment of the present invention.

[0025] FIG. 2 is a conceptual diagram of a piezoelectric layer having an internal electrode formed (arranged) according to one embodiment of the present invention.

[0026] Figure 3 is a conceptual diagram of an external electrode formed on the outside of a piezoelectric element.

[0027] FIG. 4 is a process flow diagram according to one embodiment of the present invention.

[0028] FIG. 5 is an SEM image of a raw material seed according to one embodiment of the present invention.

[0029] FIG. 6 is an SEM image of a basic specimen containing a culture seed according to one embodiment of the present invention.

[0030] FIG. 7 is an SEM image of a stacked piezoelectric element containing a culture seed according to one embodiment of the present invention.

[0031] FIG. 8 is a BBO profile graph according to one embodiment of the present invention.

[0032] FIG. 9 is a sintering profile graph according to one embodiment of the present invention.

[0033] FIG. 10 is a block diagram of a piezoelectric element according to one embodiment of the present invention.

[0034] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

[0035] The embodiments are provided to more fully explain the invention to those skilled in the art, and the following embodiments may be modified in various different forms, and the scope of the invention is not limited to the following embodiments. Rather, these embodiments are provided to make the disclosure more faithful and complete and to fully convey the spirit of the invention.

[0036] The terms used herein are for describing specific embodiments and are not intended to limit the invention. Additionally, the singular form in this specification may include the plural form unless the context clearly indicates otherwise. Terms such as “comprising,” “having,” and “having” in this application are intended to specify the presence of features, numbers, steps, actions, components, parts, or combinations thereof of the invention, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0037] In the description of the embodiments, where each layer (film), region, pattern, or structure is described as being formed "on" or "under" the substrate, each layer (film), region, pad, or pattern, "on" and "under" include both being formed "directly" and "indirectly" through another layer. In addition, the reference for the top or bottom of each layer is, in principle, based on the drawings.

[0038] The drawings are intended solely to facilitate an understanding of the concept of the present invention and should not be interpreted as limiting the scope of the invention. Additionally, relative thicknesses, lengths, or sizes in the drawings may be exaggerated for convenience and clarity of explanation.

[0039] A piezoelectric actuator according to one embodiment of the present invention can be applied to various fields such as mobile phone side key haptics, ultra-long distance ultrasonic sensors, actuators for 3D haptics, and directional speakers.

[0040] A piezoelectric actuator according to one embodiment of the present invention is composed of a bimorph type piezoelectric element, but is not limited thereto, and various types of piezoelectric elements such as unimorphs may be applied.

[0041] A piezoelectric actuator according to one embodiment of the present invention may include one or more piezoelectric layers (130) sintered with piezoelectric ceramic powder and electrodes disposed on one or both sides (upper and lower surfaces) of the piezoelectric layers (130), and the piezoelectric ceramic powder may include a culture seed (210) processed through a seed culture step (S3).

[0042] The piezoelectric actuator may be composed of a stacked piezoelectric element (100) in which a piezoelectric layer (130) is stacked.

[0043] The piezoelectric ceramic powder may include a first ceramic powder manufactured by processing the ceramic powder in the powder manufacturing step (S1) and a culture seed (210) processed through the seed culture step (S3).

[0044] The piezoelectric ceramic powder may include at least one of PMN-based ceramics, PNN-based ceramics, PNN-PZT-based ceramics, and PMN-PNN-PZT ceramics. Preferably, it may be a PNN-PZT-based ceramic, but the composition is not limited to the above ceramics.

[0045] The culture seed may include at least one of BaTIO3, PbTIO3, LaNiO3, and BiFeO3. Preferably, it may be BaTIO3, but the composition is not limited to the above compositions, and any seed composition capable of improving the vibration acceleration (G) characteristics of the piezoelectric ceramic element may be included.

[0046] The piezoelectric element (100) may include piezoelectric ceramic powder.

[0047] FIG. 1 is a conceptual diagram of a piezoelectric element (100) according to one embodiment of the present invention. FIG. 2 is a conceptual diagram of a piezoelectric layer (130) in which an internal electrode (110) is formed (arranged) according to one embodiment of the present invention. FIG. 3 is a conceptual diagram of an external electrode (120) formed on the outside of the piezoelectric element (100).

[0048] Referring to FIGS. 1 to 3, the piezoelectric element (100) may be composed of an internal electrode (110), an external electrode (120), and a piezoelectric layer (130).

[0049] The internal electrode (110) may be composed of a first internal electrode (111), a second internal electrode (112), a third internal electrode (113), and a fourth internal electrode (114).

[0050] The external electrode (120) may be composed of a first external electrode (121) and a second external electrode (122).

[0051] The piezoelectric layer (130) may be composed of a first piezoelectric layer (131) and a second piezoelectric layer (132).

[0052] The internal electrode (110) is formed on one or both sides of the piezoelectric layer (130).

[0053] For example, a first internal electrode (111) and a second internal electrode (112) are formed on one or both sides of the first piezoelectric layer (131).

[0054] A third internal electrode (113) and a fourth internal electrode (114) are formed on one or both sides of the second piezoelectric layer (132).

[0055] The internal electrode (110) and the external electrode (120) may be composed of various printing electrodes containing conductors such as Ag, Au, Pt, Pd, Cu, Ni, etc.

[0056] The first internal electrode (111) extends in the opposite direction to the second internal electrode (112). The third internal electrode (113) extends in the opposite direction to the fourth internal electrode (114).

[0057] The external electrode (120) can be electrically connected to the internal electrode (110) in the form of a termination. Additionally, vias of a predetermined diameter can be formed in the piezoelectric element (100) or the piezoelectric layer (130), and a conductive material can be filled inside the vias. As a result, the internal and external electrodes (110, 120) can be electrically connected to each other.

[0058] The first internal electrode (111) can be electrically connected to the first external electrode (121), the second internal electrode (112) can be electrically connected to the second external electrode (122), the third internal electrode (113) can be connected to the third external electrode (123), and the fourth internal electrode (114) can be electrically connected to the fourth external electrode (124).

[0059] The piezoelectric layer (130) can be formed into a thin single-layer film by performing a polishing process on a thick-film type piezoelectric ceramic.

[0060] The piezoelectric layer (130) includes a form in which the first piezoelectric layer (131) and the second piezoelectric layer (132) are sequentially stacked.

[0061] The piezoelectric layer (130) may include piezoelectric ceramic powder (133), such as PNN-PZT ceramic, PMN ceramic, PNN ceramic, and PMN-PNN-PZT ceramic, and preferably may include PNN-PZT ceramic powder.

[0062] Additionally, the piezoelectric layer (130) may include not only polycrystalline ceramics such as PZT, but also single-crystal piezoelectric materials such as PMN-PT, PZN-PT, PIN-PT, and PYN-PT, flexible piezoelectric polymer materials such as PVDF and PVDF-TrFE, and lead-free piezoelectric novel materials such as BNT (BaNiTiO3) and BZT-BCT.

[0063] Meanwhile, FIG. 2 according to one embodiment of the present invention is a drawing in which the shape of the electrodes (111, 112, 113, 114) formed in FIG. 1 is omitted, in the form of the electrodes (111, 112, 113, 114) formed by extending from the side to the center of the piezoelectric layer (130) and intersecting as in FIG. 1.

[0064] FIG. 4 is a process flow diagram according to one embodiment of the present invention.

[0065] Referring to FIG. 4, a process for manufacturing a piezoelectric element according to one embodiment of the present invention includes a powder manufacturing step (S1), a slurry manufacturing step (S2), a seed culture step (S3), a casting step (S4), and a post-casting step (S5).

[0066] Additionally, a via punching step for creating vias in the piezoelectric element (100) may be included depending on the type / shape of the piezoelectric element (100) or the user's needs.

[0067] The numerical values ​​applied to the above steps are representative values, and nearby values ​​may fall within the scope of the invention.

[0068] The powder manufacturing step (S1) may include the following three steps (1st, calcination / siev, 2nd).

[0069] 1st step: Weigh yttria-stabilized zirconia balls (10Φ) and solvent into a 10L pot, mill (or mix) them in the equipment for 24 hours, and then dry them in a constant temperature bath at 75℃ for 20 hours.

[0070] Calcination and Sieving: Dry powder is sieved to 140 mesh and then calcined at 850°C.

[0071] 2nd step: After calcining the powder, sift it again through 200 mesh to remove large particles, then mill (or mix) and dry it for 48 hours in the same manner as the 1st step.

[0072] The slurry manufacturing step may include the following three steps (first, binder combination, second).

[0073] 1st step: Yttria-stabilized zirconia balls (10Φ), solvent (toluene, ethanol), and dispersant are added to a 10L pot and milled (or mixed) at 160 rpm for 24 hours.

[0074] Binder combination: Combine a solvent (toluene, ethanol), PVB, and a plasticizer, and melt at 300 rpm for 24 hours.

[0075] Second: Add the combined binder to the prepared first slurry and mill (or mix) at 160 rpm for 24 hours.

[0076] The seed culture step (S3) may include the process of the following steps.

[0077] In the slurry manufacturing stage, the slurry and balls are separated after secondary milling (or / mixing) is completed.

[0078] Step to obtain the first seed: To leave only plate-shaped and large particles (larger than a set size) from the raw seed, the material is separated in an ultrasonic cleaner for 30 minutes and the small particles are discarded to obtain the first seed.

[0079] Step to obtain the second seed: The first seed is added to the separated slurry, the slurry with the added first seed is placed in a high-speed air-rotating stirrer and milled (or mixed) for 15 minutes to obtain the second seed.

[0080] Step to obtain culture seed: A second seed, which has completed milling in a high-speed stirrer, is milled (or mixed) in the facility at a medium speed of 100 rpm for 24 hours to obtain a culture seed (210).

[0081] In the seed culture step (S3), the standard for large particles may vary depending on the example. Additionally, the time values ​​in the above step are representative values, and if they are nearby values, they may fall within the scope of the invention.

[0082] The casting step (S4) may include a process of casting the components prepared in the powder manufacturing step and the seed culture step (S3).

[0083] The post-casting step (S5) includes a printing / lamination step, a BBO / sintering step, a polarization step, and a characteristic verification step.

[0084] The printing / stacking step may include printing internal electrodes (110) on one or both sides of the piezoelectric layer (130) and stacking the piezoelectric layer (130) for a multilayer structure.

[0085] The BBO / Binder Burn-Out and Sintering step may include a process of removing the binder (binder agent) within the molded body by heating at a temperature of 310°C or higher and 330°C or lower for a period of 1 hour 30 minutes or more and 2 hours 30 minutes or less in the BBO (Binder Burn-Out) step, and then sintering by heating at a temperature of 900°C or higher and 920°C or lower for a period of 5 hours or more and 7 hours or less in the Sintering step.

[0086] The polarization formation step may include a process of applying an external electric field to the element to align internal electric dipoles so that a piezoelectric effect is manifested.

[0087] The characteristic verification step involves testing the physical and electrical properties of the finally completed device to confirm whether it possesses the desired piezoelectric performance, and may include a process of evaluating various characteristics such as the piezoelectric coefficient, mechanical strength, and electrical responsiveness.

[0088] Meanwhile, in order to leave only plate-shaped and large particles from the raw material seed, the device used for particle separation is not limited to an ultrasonic cleaner, and any device capable of particle separation can be used as an alternative.

[0089] In addition, the device used to mill (or mix) the slurry with the first seed added is not limited to a high-speed stirrer, and any device that can be used for milling (or mixing) may be used as an alternative.

[0090] Meanwhile, if the particle size is too large or lumpy, the culture seed (210) may not react, so the seed culture step (S3) may include a process of breaking, grinding, and mixing the raw seed (200) particles through milling (or mixing).

[0091] The culture seed (210) exhibits higher piezoelectric properties and effects when the arrangement is a uniformly laid structure (e.g., a plate-like structure).

[0092] If the culture seed (210) is added from the powder manufacturing step (S1) or the slurry manufacturing step (S2), the plate-like structure is broken and the characteristic effect of the culture seed (210) can be reduced.

[0093] The culture seed (210) particles can be formed to a size of about 20 μm, and can be formed to a size of 10 μm to 30 μm.

[0094] The culture seed (210) may include at least one of BaTiO3, PbTiO3 and LaNiO3, and preferably may be composed of BaTiO3.

[0095] A piezoelectric ceramic powder according to one embodiment of the present invention has a composition of 0.5Pb(Ni (1-X) Nb (X) )O3- 0.5Pb(Zr (1-y) Ti (y) It can be composed by adding a culture seed (BaTiO3 1.5wt% to 2.5wt%) to a PNN-PZT series ceramic of )O3. (The above X and Y values ​​may be greater than 0 and less than 1.)

[0096] Meanwhile, the present invention differs from conventional inventions for manufacturing piezoelectric elements in that a seed is added to a manufactured slurry and then cast after milling or mixing.

[0097] FIG. 5 is an SEM image of a raw material seed (200) according to one embodiment of the present invention.

[0098] Referring to FIG. 5, the raw material seed (200) may include a plate-like structure.

[0099] The particles of the raw material seed (200) can be formed with a size of approximately 20 μm, and can be formed with a size of 10 μm to 30 μm.

[0100] The raw material seed (200) particles may include at least one of BaTiO3, PbTiO3, LaNiO3 and BiFeO3, and preferably may be composed of BaTiO3, but are not limited to the above compositions and may include a composition capable of improving the vibration acceleration characteristics of the piezoelectric ceramic element.

[0101] FIG. 6 is an SEM image of a basic specimen containing a culture seed according to one embodiment of the present invention.

[0102] FIG. 7 is an SEM image of a stacked piezoelectric element containing a culture seed according to one embodiment of the present invention.

[0103] FIG. 6 is an SEM image (scale bar 20 μm) of a base specimen to which a culture seed (210) obtained in the seed culture step (S3) is added to a PNN-PZT series ceramic, and FIG. 6 is an SEM image (scale bar 20 μm) of a stacked piezoelectric element to which a culture seed (210) obtained in the seed culture step (S3) is added to a PNN-PZT series ceramic. The base specimen has specifications of 10*10*1T (width 10 mm, height 10 mm, thickness 1 mm).

[0104] Referring to FIGS. 6 and 7, it can be seen that grains (220), formed by sintering ceramic powder, slurry, etc., are distributed around a culture seed (210). When comparing the images of the base specimen FIG. 6 and the stacked element FIG. 7, it can be seen that the culture seed (210) and grains (220) have grown compared to the base specimen. This is because the growth of the grains (220) around the culture seed (210) is accelerated as the seed is sintered and grows on the piezoelectric element, and as the size of the grains (220) increases, the piezoelectric properties (e.g., vibration acceleration) of the piezoelectric element can be improved.

[0105] That is, according to FIGS. 6 and 7, when a culture seed (210) is added to a piezoelectric element, the growth of surrounding grains (220) can also be accelerated as the seed grows.

[0106] Meanwhile, the piezoelectric element to which the culture seed (210) of FIGS. 6 and 7 is added includes a PNN-PZT series ceramic, but is not limited thereto, and may include various ceramic series such as PMN series ceramic, PNN series ceramic, and PMN-PNN-PZT.

[0107] Additionally, the culture seed (210) included in the piezoelectric ceramic powder of FIGS. 6 and 7 may be composed of at least one of BaTiO3, PbTiO3, LaNiO3 and BiFeO3, and preferably may include BaTiO3, but is not limited thereto.

[0108] In addition, the concentration of the culture seed (210) in the piezoelectric ceramic powder may be 1.5 wt% to 2.5 wt%, but is not limited thereto.

[0109] FIG. 8 is a BBO profile graph according to one embodiment of the present invention.

[0110] Referring to FIG. 8, the BBO (Binder Burn-Out) step may include a process of removing the binder (binder) within the molded body by heating at a temperature of 310°C or higher and 330°C or lower for a period of 1 hour 30 minutes or longer and 2 hours 30 minutes or shorter.

[0111] FIG. 9 is a sintering profile graph according to one embodiment of the present invention.

[0112] The sintering step may include a process of sintering by heating at a temperature of 900°C or higher and 920°C or lower for a period of 5 hours or more and 7 hours or less.

[0113] FIG. 10 is a block diagram of a piezoelectric element according to one embodiment of the present invention.

[0114] Referring to FIG. 10, the piezoelectric element (100) is composed of an internal electrode (110), an external electrode (120), and a piezoelectric layer (130).

[0115] The internal electrode (110) includes a first internal electrode (111), a second internal electrode (112), a third internal electrode (113), and a fourth internal electrode (114).

[0116] The external electrode (120) includes a first external electrode (121), a second external electrode (122), a third external electrode (123), and a fourth external electrode (124).

[0117] The piezoelectric layer (130) includes a first piezoelectric layer (131) and a second piezoelectric layer (132).

[0118] The piezoelectric layer (130) may include piezoelectric ceramic powder to which a culture seed (210) is added.

[0119] The present invention will be explained in more detail through the following test examples, but the following test examples are not intended to limit the scope of the invention and should be interpreted as being for the purpose of aiding understanding of the invention.

[0120] [Test Example]

[0121] The piezoelectric element of the test example is composed of component A (PNN-PZT+seed), component B (PNN-PZT), and component C (PMW-PZT-PNN) according to composition.

[0122] The A component (PNN-PZT + seed) piezoelectric element is a piezoelectric element manufactured according to one embodiment of the present invention, comprising a PNN-PZT series ceramic powder (composition: 0.5Pb(Ni (1-X) Nb (X) )O3- 0.5Pb(Zr (1-y) Ti (y) It is a piezoelectric element prepared by adding a culture seed (composition: BaTiO3 1.5wt% to 2.5wt%) obtained in a seed culture step (S3) to )O3). (The above X and Y values ​​are greater than 0 and less than 1)

[0123] The B component (PNN-PZT) piezoelectric element is a composition in which no culture seed is added to the above PNN-PZT+seed, and is a PNN-PZT series ceramic powder (Composition: 0.5[Pb(Ni (1-X) Nb (X) ) - 0.5Pb(Zr (1-y) Ti (y) It is a piezoelectric element manufactured from O3. (The above X and Y values ​​are greater than 0 and less than 1)

[0124] The C component (PMW-PNN-PZT) piezoelectric element is a composition in which PWM is added instead of a seed to the above PNN-PZT+seed, and is a PMW-PNN-PZT series ceramic powder (Composition: P0.99[Pb(Mg (1-X) W (X) ) 0.03 (Ni (1-y) Nb (y) ) 0.07~0.09 (Zr 0.5 Ti 0.5) 0.86~0.94 It is a piezoelectric element manufactured from O3. (The above X and Y values ​​are greater than 0 and less than 1)

[0125] The piezoelectric element used in the test example has a shape of 16 mm in width, 4 mm in height, and 0.6 mm in thickness, and is a bimorphic element containing 11 layers of piezoelectric layers each.

[0126] <Test Example>

[0127] 1. Measurement of vibration acceleration

[0128] For piezoelectric elements A to C, vibration acceleration (G) values ​​according to frequency (Hz) and weight (g) were measured and are shown in Table 1 below.

[0129] Test No. Frequency (Hz) Weight (g) A (PNN-PZT+Seed) B (PNN-PZT) C (PMW-PNN-PZT) 1 2000 3.87 3.44 2.56 22500 5.72 5.31 4.15 33000 8.64 7.96 6.16 4200 208.33 7.41 5.51 5250 2019.38 17.77 13.58 6300 2018.11 16.76 12.48

[0130] As can be seen from Table 1 above, by examining the test results of Tests 1 to 6 according to the composition of the present invention, it can be confirmed that the piezoelectric element A of the present invention exhibited the highest vibration acceleration (G) value under the same frequency and weight conditions. 2. Measurement of D33 (piezoelectric constant) value

[0131] For the piezoelectric elements A to C, the piezoelectric constant D33 was measured using a measuring device and is shown in Table 2 below.

[0132] Component Test No. Capacitance (nF) Dielectric Loss (%) Resonant Frequency (fr) Resonant Resistance (Zr) Anti-Resonant Frequency (fa) KpQmD33A7 4.96 2.15 160.94 12.06 195.6 0.64 44 51.2 11052A8 4.91 2.13 161.45 12.22 196.7 0.64 785 0.38 1035A9 5.02 2.17 160.58 11.94 195.6 0.64 74 50.77 1043B10 4.90 2.21 62.40 12.24 197.00.64 185 1.01 947B11 4.872 .3162.8012.48197.00.638350.74967B124.932.2162.6012.56197.00.640049.60973C131.9462.23159.5028.88191.7 50.629057.66647C141.9392.30159.5028.78191.750.629058.07635C152.0112.25158.7528.09191.750.635756.45671

[0133] As can be seen from Table 2 above, when examining the test results of tests 7 to 15 according to the composition of the present invention, it can be confirmed that the A piezoelectric element of the present invention exhibited the highest D33 value. (Capacitance: capacitance, Dielectric loss: dielectric loss, Kp: electromechanical coupling factor, Qm: mechanical quality factor, D33: piezoelectric constant) When combining the results of Tables 1 and 2, the PNN-PZT ceramic series piezoelectric element with added culture seed according to one embodiment of the present invention exhibits higher vibration acceleration (G) and D33 than conventional PNN-PZT ceramic and PMW-PNN-PZT ceramic series piezoelectric elements.

[0134] That is, when a piezoelectric element is manufactured by adding a culture seed (210) to piezoelectric ceramic powder, a higher value of vibration acceleration (G) and piezoelectric constant can be obtained compared to conventional piezoelectric elements, and high electrical characteristics can be exhibited compared to the same number of layers, so the number of layers can be reduced compared to existing ones, which is advantageous in price competition.

[0135] In addition, since it is manufactured using existing PNN-PZT series ceramics capable of high piezoelectric properties and low-temperature sintering, it is possible to achieve savings in time and cost.

[0136] The foregoing description is merely an illustrative explanation of the technical concept of the present invention, and those skilled in the art to which the present invention pertains will be able to make various modifications and variations within the scope of the essential characteristics of the present invention. Accordingly, the embodiments disclosed in the present invention are intended to explain, not limit, the technical concept of the present invention, and the scope of the technical concept of the present invention is not limited by these embodiments. The scope of protection of the present invention shall be interpreted by the claims below, and all technical concepts within an equivalent scope shall be interpreted as being included within the scope of rights of the present invention.

[0137] Although various embodiments have been described above, it should be understood that various modifications are possible. For example, suitable results may be achieved even if the described techniques are performed in a different order, and / or the elements of the described system, structure, device, circuit, etc. are combined in a different way, or are replaced or supplemented by other elements or equivalents. Accordingly, other embodiments fall within the scope of the claims set forth below.

Claims

1. One or more piezoelectric layers formed by sintering piezoelectric ceramic powder; and Electrodes disposed on one or both sides of the piezoelectric layer; comprising The above piezoelectric ceramic powder is, Containing culture seeds processed through a seed culture step, Piezoelectric actuator.

2. In Paragraph 1, The above culture seed contains BaTiO3, Piezoelectric actuator.

3. In Paragraph 2, A piezoelectric actuator in which the concentration of the culture seed in the above piezoelectric ceramic powder is 1.5 wt% to 2.5 wt%.

4. In Paragraph 2, The above culture seed has a plate-like structure. Piezoelectric actuator.

5. In Paragraph 1, The above piezoelectric ceramic powder includes PNN-PZT-based ceramics, and The composition of the above PNN-PZT-based ceramic is 0.5Pb(Ni (1-X) Nb (X) )O3- 0.5Pb(Zr (1-y) Ti (y) )O3, and the above X and Y values ​​are greater than 0 and less than 1, Piezoelectric actuator.

6. In Paragraph 1, The above culture seed comprises at least one of PbTiO3, LaNiO3, and BiFeO3, Piezoelectric actuator.

7. A method for manufacturing a piezoelectric actuator that produces a piezoelectric actuator, Powder manufacturing step for manufacturing the first ceramic powder; Slurry manufacturing step for manufacturing a slurry; A seed culture step for preparing a culture seed using a raw seed and the slurry; and A casting step for producing piezoelectric ceramic powder by casting the first ceramic powder produced in the powder manufacturing step and the culture seed produced in the seed culture step; comprising Method for manufacturing a piezoelectric actuator.

8. In Paragraph 7, The seed culture step for generating the above-mentioned culture seeds is, A step of obtaining a first seed by separating particles larger than a set size from the above raw material seed; A step of adding the first seed to the above slurry and milling or mixing to obtain a second seed; and A step of obtaining the culture seed by milling or mixing the second seed; comprising Method for manufacturing a piezoelectric actuator.

9. In Paragraph 7, The above culture seed contains BaTiO3, Method for manufacturing a piezoelectric actuator.

10. In Paragraph 9, The concentration of the culture seed in the above piezoelectric ceramic powder is 1.5 wt% to 2.5 wt%, Method for manufacturing a piezoelectric actuator.

11. In Paragraph 9, The above culture seed has a plate-like structure, Method for manufacturing a piezoelectric actuator.

12. In Paragraph 7, The above piezoelectric ceramic powder includes PNN-PZT-based ceramics, and The composition of the above PNN-PZT-based ceramic is 0.5Pb(Ni (1-X) Nb (X) )O3- 0.5Pb(Zr (1-y) Ti (y) )O3, and the above X and Y values ​​are greater than 0 and less than 1, Method for manufacturing a piezoelectric actuator.

13. In Paragraph 7, The above culture seed comprises at least one of PbTiO3, LaNiO3, and BiFeO3, Method for manufacturing a piezoelectric actuator.

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