WO2008126946A1 - Transformateur piézoélectrique du type à surface incurvée tridimensionnelle et son procédé de fabrication - Google Patents

Transformateur piézoélectrique du type à surface incurvée tridimensionnelle et son procédé de fabrication Download PDF

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Publication number
WO2008126946A1
WO2008126946A1 PCT/KR2007/001762 KR2007001762W WO2008126946A1 WO 2008126946 A1 WO2008126946 A1 WO 2008126946A1 KR 2007001762 W KR2007001762 W KR 2007001762W WO 2008126946 A1 WO2008126946 A1 WO 2008126946A1
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Prior art keywords
electrode
piezoelectric
piezoelectric transformer
curved surface
injection molding
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PCT/KR2007/001762
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English (en)
Inventor
Tae-Shik Yoon
Man-Sun Yun
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Tae-Shik Yoon
Man-Sun Yun
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Application filed by Tae-Shik Yoon, Man-Sun Yun filed Critical Tae-Shik Yoon
Priority to PCT/KR2007/001762 priority Critical patent/WO2008126946A1/fr
Publication of WO2008126946A1 publication Critical patent/WO2008126946A1/fr

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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/40—Piezoelectric or electrostrictive devices with electrical input and electrical output, e.g. functioning as transformers

Definitions

  • the present invention relates, generally, to a high-power piezoelectric transformer having a 3-dimensional (3D) curved surface shape and a method of manufacturing the same, and more particularly, to a 3D curved surface type piezoelectric transformer, which includes a piezoelectric body, formed of piezoelectric material, and electrode parts formed on a first upper curved surface and a second lower curved surface of the piezoelectric body, respectively, to thus enable the simultaneous generation of normal strain and shear strain.
  • 3D curved surface type piezoelectric transformer which includes a piezoelectric body, formed of piezoelectric material, and electrode parts formed on a first upper curved surface and a second lower curved surface of the piezoelectric body, respectively, to thus enable the simultaneous generation of normal strain and shear strain.
  • piezoelectric transformers functioning as devices for converting mechanical energy into electrical energy
  • C. E. Rosen et. al. of the GE Company, USA in 1957.
  • barium titanate which has a voltage step-up range of only about 50-60 times under no load conditions, and thus had limitations in the practical applicability thereof.
  • novel piezoelectric material composed mainly of Pb (Zr, Ti) O 3 , has been discovered, making it possible to realize the step-up of higher voltages, therefore leading to full-scale research for practical applications .
  • Such a piezoelectric transformer has the following advantages, compared to electromagnetic wound-type transformers.
  • the piezoelectric transformer may be manufactured to be smaller, slimmer and lighter because a winding process is not needed. Further, productivity may be increased upon mass production, and, upon high-frequency operation, it is possible to achieve high efficiency because magnetic loss, such as eddy current loss or hysteresis loss, which has occurred in the wound-type transformer, is not caused. Furthermore, in the course of the change of energy using the piezoelectric transformer, the conversion into magnetic energy, as in the wound-type transformer, does not occur, desirably minimizing electromagnetic induction interference. Although the wound- type transformer may cause fires when it shorts and fails, the piezoelectric transformer is in an open state when it fails, and thus the failure does not exacerbate the situation.
  • the voltage step-up ratio of the wound-type transformer is determined by the winding factor, but the piezoelectric transformer has a voltage step-up ratio varying depending on the material properties, electrode structures, dimensions, and load properties. From the point of view of output power for changing the secondary side so that it has high voltage and low current, as the wound-type transformer should increase the winding factor, a leakage component is increased.
  • the piezoelectric transformer adopts electrical-mechanical (primary side) -mechanical-electrical (secondary side) combination, and thus efficiency of 90% or more may be realized. In the case where this transformer is applied as a stabilizer, energy may be greatly saved compared to electronic stabilizers used in conventional discharge lamps.
  • the Rosen type transformer having a planar structure, has a driving part and an output part, which are polarized in directions which are perpendicular to each other, and the stress convergence at the boundary thereof is very intense. Moreover, since the output part is polarized through the application of a high electric field (3 kV/rran) , such polarization is difficult to realize, and high current is also difficult to obtain due to the small electrode area of the output terminal. Hence, this type is unsuitable for lighting a high-current lamp, such as a fluorescent lamp.
  • an object of the present invention is to provide a piezoelectric transformer, which is of a single-plate type but enables the step-up of voltage in the same level as a multilayer type, to increase the low output current and output voltage, which are disadvantages of a low-power piezoelectric transformer.
  • Another object of the present invention is to provide a piezoelectric transformer, which has various electrode structures and polarization direction arrangements using a piezoelectric element manufactured to have a new shape through power injection molding.
  • a further object of the present invention is to provide a high-efficiency piezoelectric inverter using the above piezoelectric transformer, which may stably light a general fluorescent lamp or three-wavelength lamp of high-voltage and high-current, which has been unable to drive using a conventional piezoelectric transformer, at a domestic input voltage (220 V/110 V) , even without the use of a wound-type transformer in the driving circuit.
  • the present invention provides a 3D curved surface type high-power piezoelectric transformer, which includes a piezoelectric body, formed of a piezoelectric material, and electrode parts formed on a first upper curved surface and a second lower curved surface of the piezoelectric body, respectively, to thus simultaneously generate normal strain and shear strain.
  • the piezoelectric transformer of the present invention includes a piezoelectric body formed through powder injection molding, an upper electrode part having an input electrode and an output electrode separately formed on the upper curved surface of the body, and a lower electrode part formed on the entire lower curved surface of the body, wherein, when the piezoelectric transformer is oscillated through the application of voltage, the displacement occurring upon contraction and expansion of the surfaces of the body is maximized at the peripheral region and the central region of the body.
  • FIGS. 1 and 2 are perspective views illustrating the piezoelectric transformer according to the present invention
  • FIG. 3 is a cross-sectional perspective view illustrating the hemispherical piezoelectric transformer of the present invention
  • FIG. 4 is a top plan view illustrating the transformer, in which predetermined electrodes are formed, according to the present invention
  • FIG. 5 is a bottom plan view illustrating the transformer in which a predetermined electrode is formed, according to the present invention
  • FIGS. 6 to 9 are cross-sectional views illustrating the mold for use in manufacturing the piezoelectric transformer of the present invention
  • FIG. 10 illustrates the polarization direction formed in the cross-section of the 3D curved surface type piezoelectric transformer according to the present invention
  • FIG. 11 illustrates the resonant frequency determined from the piezoelectric transformer, polarized as in FIG. 6;
  • FIGS. 12 and 13 illustrate the vibration displacement of each cross-section upon contraction vibration and expansion vibration
  • FIGS. 14 and 15 illustrate the results of 3D display of the vibration displacement on the surface of the 3D hemispherical piezoelectric transformer
  • FIGS. 16 and 17 illustrate the results of quantitative analysis for the maximum strain of the output side of each of the piezoelectric transformer of the present invention and a conventional Rosen type piezoelectric transformer;
  • FIGS. 18 and 19 illustrate the actual upper and lower shapes of an injection molded body, produced according to the present invention
  • FIGS. 20 and 21 illustrate the electrode structure formed after a sintering process, according to the present invention
  • FIG. 22 illustrates a scanning electron micrograph showing the fine texture of an internal fractured surface of the sintered sample
  • FIG. 23 illustrates the results of measurement of the resonance/anti-resonance impedance curve of a primary side electrode (oscillation part) ;
  • FIGS. 24 and 25 illustrate the construction of measurement apparatuses for comparing the voltage step-up ratios
  • FIG. 26 illustrates the results of input and output voltages, measured using the apparatus of FIG. 24;
  • FIG. 27 illustrates the output waveform, measured at standard resistance R ⁇ using the apparatus of FIG. 25;
  • FIG. 28 illustrates the final results of measurement of the voltage step-up ratio
  • FIGS. 29 and 30 illustrate the electrode configuration according to one embodiment of the present invention
  • FIGS. 31 and 32 illustrate the electrode configuration according to another embodiment of the present invention
  • FIG. 33 illustrates the polarization direction arrangement
  • FIGS. 34 and 35 illustrate the electrode configuration according to a further embodiment of the present invention.
  • FIG. 1 is a perspective view of the piezoelectric transformer of the present invention
  • FIG. 3 is a cross- sectional view of the piezoelectric transformer of FIG. 1.
  • FIGS. 3 and 4 are a top plan view and a bottom plan view, respectively, of the piezoelectric transformer having electrodes.
  • the piezoelectric transformer of the present invention includes a 3D curved surface type piezoelectric body 100 formed of a piezoelectric material, and electrode parts 200, 300 formed on a first upper curved surface and a second lower curved surface of the piezoelectric body 100, respectively.
  • the 3D curved surface type is preferably provided in the form of a hemispherical shape, any shape may be used, as long as it is a 3D curved surface enabling the presence of a shear strain component mentioned below.
  • the piezoelectric transformer of the present invention is classified into two types, depending on the polarization direction of the input and output sides.
  • the piezoelectric transformer is in the form of the electrode structure, in which the input and output sides are polarized in the upper and lower directions, the lower electrode part, printed on the entire lower curved surface of the body, is used as a common ground of the input and output parts, one of the divided upper electrode regions is set as an input side, and the other electrode thereof serves as the output side.
  • the electrode structure may be formed into various configurations in a manner such that the input side electrode is polarized in the upper and lower directions and the output side electrode is set to be in a circumferential direction after the shapes of upper and lower electrode parts are set to be the same, thus making it possible to provide a piezoelectric transformer, which may undergo optional designs suitable for corresponding uses, for example, various designs for electrode shapes, electrode structures, and polarization directions, if needed.
  • a piezoelectric transformer which may undergo optional designs suitable for corresponding uses, for example, various designs for electrode shapes, electrode structures, and polarization directions, if needed.
  • the piezoelectric transformer of the present invention may have a relatively higher voltage step-up ratio than conventional Rosen type planar piezoelectric transformers.
  • Powder injection molding is a combined technique of plastic injection molding, which can be used to accurately manufacture products having 3D complicated shapes in large quantities, and powder metallurgy, and includes a mixture preparation step of mixing powder with a binder at a predetermined ratio to thus prepare a pellet for injection molding (1 st step) , an injection molding step of subjecting the pellet to injection molding using a mold to have a predetermined shape to thus produce an injection molded body (2 nd step) , a binder removal step of removing the binder from the injection molded body to thus obtain a degreased body (3 rd step) , and a sintering step of sintering the degreased body at a high temperature, thus manufacturing a final product (4 th step) .
  • material powder is composed mainly of Pb (Zr, Ti) O 3 , and each element (Pb, Zr, Ti) powder is uniformly dispersed and ground through high-energy ball- milling to an average particle size of 2.0 ⁇ m or less.
  • a binder polybutyl methacrylate (PBMA) and paraffin wax (PW) are added at a predetermined ratio within the range of 90:10-10:90.
  • the amount of PBMA and PW, contained in the predetermined ratio, is set to be 60-95 wt% based on the total wt%, the balance being ethylenevinylacetate (EVA) , dissolved in a petroleum solvent.
  • PBMA polybutyl methacrylate
  • PW paraffin wax
  • the material powder and the binder are weighed to be about 45-55% by volume, mixed at 150 0 C for about 1 hour using a pressure kneader having two banbury type blades for rotation, cooled, ground into pellets for injection molding, and granulated.
  • 2 nd Step Injection Molding and Design of Mold Therefor
  • FIGS. 6 to 9 Using any mold of FIGS. 6 to 9 in a molding machine having the same structure as a general plastic injection molding machine, an injection molded body is produced.
  • the mold for injection molding typically adopts a cold runner system or a hot runner system. In the two systems, the powder mixture is filled into a cavity via a sprue, a runner, and a gate, thus forming the injection molded body.
  • FIG. 6 illustrates the mold, ' in which the gate 14 is positioned at the top of the piezoelectric transformer.
  • the reason why the gate is positioned at the top of the piezoelectric transformer is that the entire surface of the piezoelectric transformer, except for the top thereof, functions in a normal piezoelectric mode and a shear piezoelectric mode at the same time. If a gate mark or fine scratches exist after the injection molding, cracking may be caused. Thus, when the gate is disposed at the top of the piezoelectric transformer, where only the normal piezoelectric mode is present, it is possible to increase the lifetime of the product somewhat even when the gate mark is present at the top after molding.
  • the mold 400 includes a fixed body 411 and a movable body 412.
  • FIG. 7 illustrates another mold, which is an improvement of the structure of FIG. 6.
  • the mold of FIG. 7 includes a protrusion 425 formed at the top of a cavity 426.
  • a piezoelectric transformer comprising the cavity 426 and the protrusion 425, may be obtained.
  • the gate mark is not formed on the surface of the injection molded body but is formed on the protrusion 425.
  • a runner 433 and a gate 434 are formed at the parting surface between a fixed body 431 and a movable body 432, such that a gate mark is formed on the side surface of a product.
  • the electrode is not formed near the gate mark, and thus the generation of defects, including cracking, may be advantageously minimized upon the operation of the piezoelectric transformer.
  • the mold of FIG. 9 has a structure similar to the mold of FIG. 8, with the exception that a gate 444 is formed at the straight portion 446 of the lower end of a product, therefore making it possible to form more electrode parts on the entire surface of a cavity 45.
  • the injection molding is conducted at a pressure of 300 MPa or less.
  • the binder used in the powder injection molding functions to impart the powder with flexibility upon injection molding to thus enable it to be loaded into the mold and to retain the molded shape after a cooling process.
  • the binder remains after degreasing, it is mainly present in the form of a carbon component, which incurs poor piezoelectric properties and abnormal crystalline grain growth, resulting in greatly- worsened properties of piezoelectric ceramic products.
  • the binder must be completely removed.
  • the removal of the binder is a process of completely removing the binder, which is present in a large amount in the injection molded body, without generating defects, including distortion or cracking. This process is recognized to be the most important in the total process, and takes a long time.
  • the removal of the binder is conducted using so-called pyrolysis or solvent extraction.
  • the removal of the binder through pyrolysis includes a removal method using evaporation. According to this method, when the injection molded body is placed on a porous substrate in a furnace and then heated to a temperature not lower than the melting point of the binder, fast gas flow is caused around the injection molded body to thus form eddy currents at the binder evaporation interface of the surface of the injection molded body, thereby removing the binder using such eddy currents without the formation of a boundary layer.
  • the injection molded body is placed on an alumina substrate so that the gate faces upward, and then the temperature is slowly increased.
  • the temperature is increased to 130 0 C, which is lower than 140 0 C, the softening temperature of the mixture, and should be maintained there for at least 20 hours. This is because the shape of the injection molded body may be distorted when maintained at a high temperature exceeding the above temperature.
  • the molded body is heated at 13O 0 C for about 20 hours, after which the temperature of the furnace is increased to 500 0 C at a rate of 0.5 ⁇ 3 °C/min and then maintained for 1 hour or longer, thereby removing 99% or more of the added binder.
  • the amount of carbon residue is reduced to 0.1% or less.
  • the temperature of the furnace is increased to 700 0 C and that temperature is maintained for 1 hour or longer, the carbon residue is reduced to 0.01% or less.
  • the heating rate may be increased to 5 °C/min.
  • the solvent extraction method is conducted by extracting only a specific material of the binder with a solvent and removing the remaining binder using heat.
  • the 3D curved surface type piezoelectric body thus degreased is sintered at 1300 0 C for 1-2 hours in a closed alumina crucible in an atmosphere containing oxygen, thus producing a 3D curved surface type piezoelectric body having a dense structure.
  • the 3D hemispherical piezoelectric body, manufactured through powder injection molding, and the disk type piezoelectric body, manufactured through powder pressing, are measured for piezoelectric properties according to the EMAS6001 standard. The results are shown in Table 1 below.
  • the resonant frequency analyzed for the polarized piezoelectric transformer is shown in FIG. 11.
  • the arrow direction shown in FIG. 10 corresponds to the polarization direction of the 3D hemispherical piezoelectric transformer of the present invention.
  • the vibration displacement, occurring at the cross-section includes contraction vibration and expansion vibration, which are illustrated in FIGS. 12 and 13, respectively.
  • FIGS. 14 and 15 illustrate the vibration displacement vector generated on the upper curved surface of the 3D hemispherical piezoelectric transformer, upon resonance expansion
  • FIG. 15 illustrates the vibration displacement vector generated in the contraction direction on the lower curved surface thereof.
  • the displacement vector which is present on the entire spherical surface, except for the center point, has the normal strain and shear strain generated at the same time, which means that d 33 and di 5 modes may be simultaneously used, thus resulting in higher voltage step-up ratios than general planar piezoelectric transformers.
  • the displacement generated at the output side has a relationship proportional to the output.
  • the maximum strain of the output side is quantitatively analyzed through simulation under the same electric field. The results are shown in FIG. 10. As seen in FIG. 16, in the longitudinal direction of the Rosen type piezoelectric transformer, the maximum total displacement is 2 x 5.385 x 10 ⁇ 8 mm, the total length is 25 mm, and the thickness is 2.5 mm,
  • Equation 1 (Strain of 3D Hemispherical Piezoelectric Transformer) / (Strain of Rosen type Piezoelectric Transformer)
  • the piezoelectric transformer of the present invention may easily assure higher output than a conventional Rosen type piezoelectric transformer.
  • FIGS. 18 and 19 The actual upper and lower shapes of the injection molded body thus produced are illustrated in FIGS. 18 and 19.
  • the electrode structure is as illustrated in FIGS. 20 and 21.
  • the scanning electron micrograph of the fine texture of the internal fractured surface of the sintered sample is shown in FIG. 22, which confirms the formation of a uniform and dense sintered body of 1.5 ⁇ 2 ⁇ m.
  • the Rosen type piezoelectric transformer has standard dimensions of 25 mm width x 7 mm length x 2.5 mm thickness.
  • the piezoelectric transformer thus manufactured is immersed in silicone oil at 150°C, and then a DC electric field of 2.5 kV/mm is applied thereto for 40 min, after which the transformer is removed from the oil, washed, and then subjected to aging at 150 0 C for 5 hours.
  • the secondary electrode of the obtained sample is short-circuited with the ground, after which the resonance/anti-resonance impedance curve of the primary side electrode (oscillation part) is measured using an HP4194 impedance/gain phase analyzer.
  • the results are shown in FIG. 23. As is apparent from these results, the primary resonant frequency is determined to be 93.9056 kHz, which is similar to the simulation results.
  • the measurement apparatus of FIG. 24 or 25 is constructed, after which a spherical wave is generated from a waveform generator, amplified to 5Vp-p using a power amplifier, and then input into the primary side electrode of the piezoelectric transformer. Thereafter, the voltage occurring at the secondary side electrode is measured using an oscilloscope.
  • a voltage probe is directly connected to the load resistor to thus measure the output voltage.
  • Equation 2 Equation 2
  • FIG. 26 shows the results of input and output voltages measured using the apparatus of FIG. 24 when the load resistance is 10 k ⁇
  • FIG. 27 shows the output waveform measured at the standard resistor of R s using the apparatus of FIG. 25 when the load resistance is 10 M ⁇ . The input and output waveforms thus measured are analyzed, and the output voltage is divided by the input voltage to thus determine the voltage step-up ratio. The final results are shown in FIG. 28. As shown in FIG.
  • the conventional Rosen type piezoelectric transformer has a maximum step-up ratio of 20 times at 10 M ⁇ , whereas the piezoelectric transformer of the present invention has a maximum step-up ratio of 290 times, which is increased by more than 14 times over the Rosen type piezoelectric transformer.
  • FIGS. 29 to 32 To use various vibration modes, occurring from the 3D curved surface type piezoelectric transformer, some upper electrode part examples are illustrated in FIGS. 29 to 32. As in FIGS. 29 and 30, while the upper and lower electrode parts have the same shapes, the electrode having a larger area (the central region of the spherical shape) is determined as a primary side electrode, and the electrode having a smaller area (the peripheral region of the spherical shape) is determined as a secondary side electrode. Thereafter, as in FIG. 33, the primary side electrode is polarized in the upper and lower directions, so that the primary electrode and the secondary electrode are polarized in a direction of a tangential line to the curved surface.
  • the primary side electrode is polarized in the upper and lower directions, so that the primary electrode and the secondary electrode are polarized in a direction of a tangential line to the curved surface.
  • electrodes may be provided in the forms shown in FIGS. 31 and 32 and may be arranged in the polarization direction seen in FIG. 33.
  • the above-mentioned electrode configurations are more effective in preventing breakdown around the boundary of the primary electrode and the secondary electrode because the primary side and the secondary side are polarized in directions which are not perpendicular to each other, in making the polarization process feasible, and in assuring a high yield and a high voltage step-up ratio.
  • the upper electrode part and the lower electrode part may be provided in the forms shown in FIGS. 34 and 35, according to a further embodiment. Accordingly, a 3D hemispherical piezoelectric transformer, which has an electrode over its entire lower surface (FIG. 35) , as the lower electrode part, and is polarized in a thickness direction, as in FIG. 10, may be provided.
  • the piezoelectric transformer manufactured to have a 3D curved surface shape using a powder injection molding technique may have various vibration modes and large vibration displacement, unlike conventional planar piezoelectric transformers, thus greatly improving the limited properties of conventional planar piezoelectric ceramics.
  • the method of the present invention is advantageous because mass productivity and dimensional accuracy are superior, and because large displacement and power may be attained without the complexity of manufacture of a layered structure, compared to other methods.
  • the above method may be applied to material having no limitation in thickness and radius of curvature, is able to realize resonant operation, and also effectively enables mass production.

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Abstract

L'invention concerne un transformateur piézoélectrique du type à surface incurvée tridimensionnelle, comprenant un corps piézoélectrique en matériau piézoélectrique et des parties électrodes formées sur une première surface incurvée supérieure et une seconde surface incurvée supérieure du corps piézoélectrique, respectivement, de manière à générer simultanément une déformation normale et une déformation de cisaillement. Le transformateur piézoélectrique est fabriqué selon un procédé de moulage par injection de poudre comprenant: une étape de préparation du mélange dans laquelle un granulé est préparé pour le moulage par injection avec un liant avec un rapport de mélange prédéterminé (première étape); une étape de moulage par injection dans laquelle le granulé est soumis au moulage par injection dans un moule pour obtenir la forme prédéterminée et, par conséquent, un corps moulé par injection (deuxième étape); une étape d'extraction du liant dans laquelle le liant est extrait du corps moulé par injection pour obtenir un corps dégraissé (troisième étape); et une étape de frittage dans laquelle le corps dégraissé est fritté à une température élevée pour obtenir un produit final (quatrième étape).
PCT/KR2007/001762 2007-04-11 2007-04-11 Transformateur piézoélectrique du type à surface incurvée tridimensionnelle et son procédé de fabrication WO2008126946A1 (fr)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4088915A (en) * 1974-02-28 1978-05-09 Pioneer Electronic Corporation Curved polymeric piezoelectric electro-acoustic transducer
KR960004386B1 (ko) * 1993-05-04 1996-04-02 쌍용양회공업주식회사 고인성, 고절연성 지르코니아 드라이버 소결체의 제조방법
US5861704A (en) * 1996-05-30 1999-01-19 Nec Corporation Piezoelectric transformer
JP2000150982A (ja) * 1998-11-10 2000-05-30 Tokin Corp 圧電トランス
JP2005175244A (ja) * 2003-12-12 2005-06-30 Toko Inc 圧電トランス
KR20070040878A (ko) * 2005-10-13 2007-04-18 윤만순 3차원 곡면 타입의 입체형상을 갖는 고출력 압전 변압기 및그의 제조방법

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4088915A (en) * 1974-02-28 1978-05-09 Pioneer Electronic Corporation Curved polymeric piezoelectric electro-acoustic transducer
KR960004386B1 (ko) * 1993-05-04 1996-04-02 쌍용양회공업주식회사 고인성, 고절연성 지르코니아 드라이버 소결체의 제조방법
US5861704A (en) * 1996-05-30 1999-01-19 Nec Corporation Piezoelectric transformer
JP2000150982A (ja) * 1998-11-10 2000-05-30 Tokin Corp 圧電トランス
JP2005175244A (ja) * 2003-12-12 2005-06-30 Toko Inc 圧電トランス
KR20070040878A (ko) * 2005-10-13 2007-04-18 윤만순 3차원 곡면 타입의 입체형상을 갖는 고출력 압전 변압기 및그의 제조방법

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