• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The piezoelectric transformer element includes a piezoelectric plate made of a ceramic material and an input electrode and an output electrode formed on the piezoelectric plate to output a voltage from the output electrode when a voltage is applied to the input electrode. The reinforcing layer is selectively disposed on the portion of the piezoelectric plate where the tensile stress is concentrated when the piezoelectric transformer element is driven. The reinforcing layer has the same composition as the ceramic material forming the piezoelectric plate, and is made of a ceramic material having a smaller particle size than the ceramic material after sintering. The method of manufacturing the piezoelectric transformer element comprises the steps of selectively disposing a reinforcing layer made of ceramic powder on the required portion of each ceramic sheet forming the piezoelectric plate of the piezoelectric transformer element, and forming and sintering the ceramic sheet and the ceramic powder. Manufacturing a piezoelectric plate. The ceramic powder has the same composition as the ceramic sheet of the piezoelectric plate and has a larger powder specific surface area than the piezoelectric plate.
    公开号:KR19990063075A
    申请号:KR1019980055150
    申请日:1998-12-15
    公开日:1999-07-26
    发明作者:스스무 사이또；다까유끼 이노이
    申请人:가네꼬 히사시；닛본덴기 가부시끼가이샤；
    IPC主号:
    专利说明:

    Piezoelectric transformer element and its manufacturing method
    BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to piezoelectric transformer elements made of ceramic materials, and more particularly, to a low profile piezoelectric transformer element and a method of manufacturing the same, which are compact, require high precision and generate high voltage.
    Conventionally, in the backlight inverter of a liquid crystal display, the inverter which lights a fluorescent tube, and the high voltage power supply circuit of a copy machine, the winding electromagnetic transformer etc. were used for the high voltage generation element. Piezoelectric transformers are attracting attention as they require reduction of electromagnetic noise, power consumption, height, and the like. Figure 1 shows the structure of a conventional symmetric Rosen tertiary stacked piezoelectric transformer. In the Rosen symmetric tertiary stacked piezoelectric transformer of a rectangular ceramic piezoelectric plate 1 having a laminated layer structure in which electrodes are formed on a surface, a drive unit in which two ends of the longitudinal piezoelectric plate 1 are used as an input portion of the piezoelectric transformer ( 21). In the drive part 21, planar input electrodes 2a, 2b and 3a, 3b are formed on the upper and lower surfaces of the piezoelectric plate 1, respectively. These two ends are polarized in the thickness direction. The electrodes 4a, 4b and 5a, 5b electrically connect the input electrodes 2a, 2b and 3a, 3b to an internal electrode (not shown) formed between the stacked layers of the piezoelectric plate 1. The center portion of the piezoelectric plate 1 forms a power generation section 22 used as an output section. In the power generator 22, output electrodes 6a and 6b are formed on the upper and lower surfaces of the piezoelectric plate 1, respectively. This central portion is polarized in the longitudinal direction of the piezoelectric element.
    Operation of a conventional piezoelectric transformer element is described below with reference to the accompanying Figures 2A-2C. FIG. 2A is a schematic cross-sectional view of the piezoelectric transformer, FIG. 2B is a graph showing the displacement of the distribution obtained in the piezoelectric transformer oscillating in the resonant mode of 3/2 wavelength in the longitudinal direction, and FIG. A graph showing the type of stress. When a voltage is applied from the external terminals 7a and 7b shown in FIG. 1 to the input electrodes 2a, 2b and 3a and 3b of the driver 21, an electric field is applied to the driver 21 in the polarization direction. As shown in Fig. 2B, the longitudinal vibration in the longitudinal direction is excited by the reverse piezoelectric effect in which the element is displaced in a direction perpendicular to the polarization direction, and the entire piezoelectric transformer vibrates. In the power generator 22 shown in Fig. 2C, mechanical deformation occurs in the polarization direction. Then, the voltage having the same frequency as the input voltage is output from the output electrodes 6a and 6b to the external terminals 8a and 8b due to the piezoelectric effect in which the potential difference occurs in the polarization direction. If the driving frequency is set equal to the resonance frequency of the piezoelectric plate 1, a very high output voltage can be obtained. The power available at the piezoelectric transformer element is proportional to the power of mechanical vibration and structurally proportional to the cross-sectional area of the piezoelectric plate 1.
    Therefore, to obtain a high output in the piezoelectric transformer element, the size of the element must be large or the vibration speed of the piezoelectric transformer element must be increased. It is not practical to increase the size because the device to be powered must be small. Therefore, the output of the piezoelectric transformer can be increased by increasing the vibration speed. However, increasing vibration speeds can exceed the mechanical strength of the device. Then, only the machine is broken and the expected output is not obtained. To increase the strength of the device while avoiding breakage of the device, fine powder must be used as the piezoelectric ceramic material and the actual size must be reduced to densify the ceramic material after firing the ceramic material. However, even if there are techniques for improving device strength by using fine powder, the finer the powder, the more difficult it is to handle. In the green sheet process, the powder is not easily dispersed, and thus the compressive density cannot be stabilized, thereby making it difficult to sufficiently strengthen the strength of the device. If the size of the ceramic particles of the driving section or the power generating section is reduced, the same piezoelectric properties that were conventionally obtained cannot be obtained even using the same applied voltage as in the prior art. To avoid degrading the efficiency of the transformer, the design must be changed to account for polarization conditions.
    It is proposed to use a technique in which the strength of the device is increased by improving the structure of the ceramic material constituting the device. For example, Japanese Unexamined Patent Publication Nos. 8-10724 and 2-100306, which disclose multilayer ceramic components, are generated by the thickness of internal electrodes and are broken or separated from multilayer ceramic components such as piezoelectric transformers or ceramic capacitors. Each spacer having a thickness substantially the same as that of the inner electrode is formed in a portion except for the inner electrode portion, so as to eliminate the step that generates. More specifically, FIGS. 3A to 3E are exploded perspective views of the piezoelectric transformer element disclosed in Japanese Unexamined Patent Publication No. 8-107241. In order to avoid rupture and separation when pressure is applied, the spacers 112a to 112e together with the internal electrodes 110a to 110e are formed at different planar positions of the laminated ceramic sheets 111a to 111e. Similarly, in Japanese Unexamined Patent Publication No. 2-100316 shown in Figs. 4A and 4B, the internal electrode 210 is formed on one ceramic green sheet 211 which partially constitutes an electric component in which parts are laminated. Is formed. The spacer 212 is formed on another ceramic green sheet 211 laminated on one ceramic green sheet 211 and surrounds the internal electrode 210 of one ceramic green sheet 211. The spacer 212 prevents rupture and separation when pressure is applied.
    In the techniques described in these references, spacers are formed only in portions of laminated ceramic members, except for internal electrodes. While these techniques are effective in preventing rupture and separation caused by stress or stress generated during sintering, it is difficult to eliminate the breakage of the device caused by stress concentrations occurring while the piezoelectric transformer is being driven. In particular, in the symmetric Rosen tertiary piezoelectric transformer shown in Fig. 1, the concentration point of the tensile stress is located on the region of the central portion of the longitudinal direction of the element in which the external electrode is to be formed, so that the spacer described above is It does not function effectively and in most cases the device is destroyed at and near the external electrode.
    The present invention has been made in consideration of the above situation of the prior art, and a piezoelectric transformer device and a method of manufacturing the same, in which a part in which tension stress is concentrated during vibration is selectively strengthened so that the device does not easily crack during driving unless the device polarization state is changed. The purpose is to provide.
    In the piezoelectric transformer element according to the present invention which achieves the above object, a reinforcing layer made of a ceramic material having the same composition as the ceramic material forming the piezoelectric plate and having a smaller particle size after sintering is tensioned when the piezoelectric transformer element is driven. It is optionally disposed on a piezoelectric plate where stress is concentrated. The piezoelectric plate is formed of a ceramic material made of ceramic powder having a specific powder surface area of 2 m 2 / g, and the reinforcing layer is made of a ceramic material having ceramic powder having a powder specific surface area corresponding to a range of 3 m 2 / g to 5 m 2 / g. Is formed. The reinforcing layer is formed to have a width in the longitudinal direction of the piezoelectric plate in a range corresponding to 5% to 12% of the piezoelectric plate length.
    In the method of manufacturing a piezoelectric transformer element, which achieves the above object, the required portion of each ceramic sheet forming the piezoelectric plate of the piezoelectric transformer element has the same composition as the ceramic sheet of the piezoelectric plate and has a powder specific surface area than that of the piezoelectric plate. Selectively disposing a reinforcing layer made of the larger ceramic powder, and forming and sintering the ceramic sheet and the ceramic powder to produce a piezoelectric plate. A ceramic material having a powder specific surface area of 2 m 2 / g is used to form the ceramic sheet of the piezoelectric plate, and ceramic powder having a powder specific surface area of 3 m 2 / g to 5 m 2 / g is used to form the reinforcing layer. do. The reinforcing layer is formed by applying a ceramic paste coating the surface of the ceramic sheet forming the piezoelectric plate.
    In the piezoelectric transformer element according to the present invention, a reinforcing layer made of a ceramic material having the same composition as the ceramic sheet forming the piezoelectric plate and having a smaller particle size than the ceramic sheet, concentrates tensile stress when the piezoelectric transformer element is driven. Is selectively disposed on the piezoelectric plate. Therefore, this part of the piezoelectric plate has a small size of particles to form a dense structure, thereby partially strengthening the strength. Therefore, the separation or rupture of the piezoelectric transformer element caused by the tensile stress generated in the piezoelectric transformer element is also prevented. In the symmetric Rosen tertiary piezoelectric transformer element, only the stress concentration unit is selectively strengthened by fine powder, and the size of the ceramic particles is the same in the driving unit or the power generating unit. Thus, the polarization conditions do not need to change
    In the manufacturing method according to the present invention, when screen printing using a ceramic paste is used in the manufacturing method of the reinforcing layer, it can be formed in a dense and stable state. Since the reinforcing layer has the same composition as the piezoelectric plate, no internal defects such as voids or separation occur during the sintering of the ceramic material.
    Other objects, features and advantages, including the above object of the present invention, will become apparent to those skilled in the art with reference to the following detailed description and accompanying drawings, which illustratively illustrate preferred embodiments that incorporate the principles of the present invention.
    1 is a perspective view showing a conventional symmetric Rosen tertiary piezoelectric transformer;
    2A-2C show the principle of operation of a conventional symmetric Rosen tertiary piezoelectric transformer;
    3A to 3E are exploded perspective views showing patterns of ceramic sheets forming conventional piezoelectric transformer elements, respectively.
    4A and 4B are exploded perspective views each showing a pattern of a ceramic sheet forming a conventional laminated electronic component.
    5 is a perspective view of a first embodiment of a piezoelectric transformer element according to the present invention applied to a symmetric Rosen tertiary piezoelectric transformer;
    FIG. 6 is a partially exploded perspective view illustrating a method of manufacturing the piezoelectric transformer element shown in FIG. 5. FIG.
    7 is a graph showing the relationship between the powder specific surface area of the reinforcing layer, the number of ruptured elements, and the efficiency of the second embodiment of the present invention in the second embodiment of the present invention.
    Fig. 8 is a graph showing the relationship between the width of the reinforcing layer, the number of ruptured elements, and the efficiency in the third embodiment of the present invention.
    Explanation of symbols for the main parts of the drawings
    1: piezoelectric plate
    2a, 2b, 3a, 3b: input electrode
    4a, 4b, 5a, 5b: side electrode
    6a, 6b: output electrode
    7a, 7b, 8a, 8b: external terminal
    9a to 9d: reinforcing layer
    10a to 10d: ceramic sheet
    11a to 11d: internal electrode
    12a to 12d: internal electrode
    21: drive unit
    22: power generating unit
    Some preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 5 is a perspective view showing the configuration of the first embodiment of the present invention, and FIG. 6 is an exploded perspective view for explaining the manufacturing method of the first embodiment. In the first embodiment, the present invention is applied to a symmetric Rosen tertiary piezoelectric transformer having a stacked layer structure. The two end portions of the rectangular piezoelectric plate 1 formed by laminating a plurality of ceramic layers form a driving portion 21 used as an input portion of the piezoelectric transformer element. Planar input electrodes 2a, 2b and 3a, 3b are formed on the upper and lower surfaces of the piezoelectric plate 1, respectively. These two ends are polarized in the thickness direction. The center part of the piezoelectric plate 1 forms the electric power generation part used as an output part. In the power generating section 22, output electrodes 6a and 6b are formed on the upper and lower surfaces of the piezoelectric plate 1, respectively. The central portion is polarized in the longitudinal direction of the piezoelectric plate 1.
    As shown in FIG. 6, in the piezoelectric plate 1, a plurality of ceramic sheets (five sheets of FIGS. 6A to 10E) are laminated. In the ceramic sheets 10a to 10e, the upper surfaces of the four lower ceramic sheets 10a to 10d are formed in the regions of the corresponding driving portions 21 together with the internal electrodes 11a to 11d and 12a to 12d, respectively. Upper surface areas of the four ceramic sheets 10a to 10d corresponding to the electric power generating unit 22 are formed between the output electrodes 6a and 6b together with the reinforcing layers 9 (9a to 9d), respectively. Five ceramic sheets 10a to 10e are stacked, pressed and sintered to form the piezoelectric plate 1. As shown in FIG. 5, side electrodes 4a, 4b and 5a, 5b are formed on each side of the drive portion 21 of the piezoelectric plate 1. The side electrodes 4a, 4b and 5a, 5b electrically connect the inner electrodes 2a, 2b to the upper or lower surfaces 3a, 3b by alternately connecting the inner electrodes in the stacking direction, or corresponding drive parts 21. Connect to the upper or lower surface of the
    In order to form the reinforcing layer 9, a ceramic paste made of a powder having the same composition as that of the ceramic sheet constituting the piezoelectric plate 1 and having a smaller particle size than the ceramic sheet, as described above, that is, the power generating portion ( 22 is applied to the central portion in the longitudinal direction of each ceramic sheet on a region superimposed on an external electrode formed at the central portion of 22). Each ceramic sheet is laminated and formed according to the same method applied to form a regular piezoelectric plate. In this case, the ratio of the width of the reinforcing layer 9 in the longitudinal direction of the piezoelectric plate 1 to the longitudinal direction of the piezoelectric plate 1 is set to be within the required range. From the description of the embodiments to be described below, the size of the particles and the width of the reinforcing layer will be apparent.
    In the piezoelectric transformer element having the above configuration, when a voltage is applied across the electrodes 2a, 2b and 3a, 3b of the drive unit 21 from the external terminals 7a, 7b, the electric field is generated from the piezoelectric plate at the drive unit 21. It is applied in the polarization direction of (1). The vertical vibration in the longitudinal direction is excited by the reverse piezoelectric effect in which the element is displaced in the direction perpendicular to the polarization direction, so that the entire portion of the piezoelectric plate 1 vibrates as shown in FIG. 2B. Due to the piezoelectric effect in which mechanical strain is generated in the polarization direction in the power generating section 22 and a potential difference occurs in the polarization direction, a voltage having the same frequency as the input voltage is output from the external terminals 8a at the output electrodes 6a and 6b. , 8b). When the piezoelectric transformer is driven as shown in FIG. 2C, the stress is concentrated at the node of vibration. In particular, the tension strain is concentrated in the center of the device in the longitudinal direction. Ceramic materials resist compressive stress, but weak against tensile strain. Therefore, the central part of the device where stress is concentrated may rupture. Since there is a reinforcing layer in the center of the piezoelectric plate 1 element, the above-described tension stress is substantially reduced to 0 by the reinforcing layer, and the rupture and separation of the piezoelectric plate 1 are prevented.
    A second embodiment of the present invention will be described. As the piezoelectric transformer element according to the second embodiment of the present invention, five layers of piezoelectric transformer elements having the configuration shown in Figs. As the material of the piezoelectric ceramic sheets 10a and 10b, a ceramic material based on PZT (PbZrO 3 -PbTiO 3 ) having a fine powder surface area of 2 m 2 / g is used. The AgPb alloy is printed on the two ends of the piezoelectric ceramic sheets 10a and 10b by screen printing to form the driving internal electrodes 11a to 11d and 12a to 12d, and the ceramic powder having the same composition as the piezoelectric ceramic sheet It is printed by screen printing to form the reinforcing layers 9a to 9d. Four types of piezoelectric plates different from each other are formed according to the size of the powder particles forming the reinforcing layers 9a to 9d. In particular, fine ceramic powders having a powder specific surface area of 2 m 2 / g, 3 m 2. / g, 4 m 2 / g, and 5 m 2 / g are used. The coating thickness and width of the reinforcing layers 9a and 9b are fixed to 25 탆 and 5 mm, respectively. Ag paste is printed on each piezoelectric plate by screen printing, and the plate has piezoelectric transformer elements having input electrodes 2a, 2b and 3a, 3b, side electrodes 4a, 4b and 5a, 5b, and output electrode 6a. , 6b). The width of each output electrode is 1 mm. A voltage of 2 kV / mm is applied to the drive and power generating units as a result element so that polarization occurs in the insulating oil at 170 ° C. Finally, samples of four piezoelectric transformer elements were obtained for each width type.
    On the input side of the piezoelectric transformer element, voltage was applied for 5 minutes in the absence of a rod having a vibration speed of 1 to 1.2 m / s. Fracture tests were performed on 10 sample pieces of each width form. 7 shows the results of the fracture test. An efficiency of 3W output is also observed when a 100Ω resistor is connected to the load. In the graph of FIG. 7, the abscissa represents the powder specific surface area of the reinforcing layer, the ordinate on the left represents the number of broken elements, and the ordinate on the right represents the conversion efficiency. As is apparent from Fig. 7, in the piezoelectric transformer according to the present invention, when the material of the reinforcing layer 9 has a powder specific surface area equal to or greater than 3 m 2 / g, the rupture of the center portion of the piezoelectric transformer element is prevented. When the powder specific surface area exceeds 5 m 2 / g, the powder mass hardens and a ceramic paste having a good dispersing capacity cannot be obtained. Therefore, the powder of the reinforcing layer 9 preferably has a powder specific surface area of 5 m 2 / g or less.
    Next, a third embodiment of the present invention will be described. In the piezoelectric transformer element according to the third embodiment of the present invention, five layers of piezoelectric transformer elements having the configuration shown in Figs. As the material of the piezoelectric ceramic sheets 10a to 10e, a ceramic material based on PZT (PbZrO 3 -PbTiO 3 ) having a powder specific surface area of about 2 m 2 / g is used. An AgPb alloy is formed on the two ends of the piezoelectric ceramic sheets 10a, 10b by screen printing to form driving internal electrodes 11a-11d and 12a-12d, has the same composition as the piezoelectric plates, and has a powder specific surface area of about Fine ceramic powder of 4 m 2 / g is printed by screen printing to form the reinforcing layers 9a to 9d. The coating thicknesses of the reinforcing layers 9a to 9d are fixed at 25 mu m, and four kinds of piezoelectric plates having different widths of 1 mm, 2 mm, 5 mm, and 7 mm are made. The resulting laminated piezoelectric plate was 42 mm long, 5 mm wide, and 1 mm thick. The ratio of the width of the reinforcing layer and the total length of the piezoelectric plates (elements) of the four types of piezoelectric plates is 2.4%, 4.8%, 11.9%, and 16.7%. The Ag paste is printed by screen printing on the piezoelectric plate and formed with the input electrodes 2a, 2b and 3a, 3b, side electrodes 4a, 4b and 5a and 5b, output electrodes 6a and 6b, and the like. The plate is calcined to obtain a transformer element. The width of each output electrode is 1 mm. A voltage of 2 kV / mm is then applied to the drive and power generating units as a result element so that polarization occurs in the insulating oil at 170 ° C. Finally, four piezoelectric transformer device samples were obtained for each width type.
    Voltage was applied for 5 minutes with no load on the input side of the piezoelectric transformer element with a vibration speed of 1 to 1.2 m / s. Fracture tests were performed on 10 sample pieces of each width form. 8 shows the results obtained in the fracture test. In all devices, rupture occurs at the center of the device. If a 100Ω resistor is connected to the load, an efficiency of 3W output is also observed. In the graph of FIG. 8, the yellow coordinate axis represents the thickness of the reinforcing layer, the left vertical coordinate represents the number of ruptured devices, and the right vertical coordinate represents the cohesive efficiency. As is apparent from Fig. 8, a ceramic paste made of powder and smaller particles having the same composition as the ceramic material forming the piezoelectric ceramic sheet is selectively applied to the portion of the piezoelectric ceramic sheet, and the tension strain is concentrated when the piezoelectric transformer is driven. When the width of the strength piezoelectric reinforcement layer is increased to be equal to or greater than 5% of the total length of the device to form the strength reinforcement layer, the rupture of the central portion of the device is stopped. In addition, when the width of the electrode is 12% or less, the piezoelectric transformer element maintains a high conversion efficiency equal to or greater than 90%.
    In the above description, the present invention is applied to a stacked piezoelectric transformer element having a plurality of ceramic sheets laminated and having an internal electrode between the stacked layers. The invention is similarly applied to single paste piezoelectric transformer elements without internal electrodes. In this case, the reinforcing layer satisfying the powder specific surface area and width described above is integrally embedded in the central portion in the longitudinal direction of the ceramic green sheet forming the piezoelectric plate. The piezoelectric plate or piezoelectric transformer element can be made by the same manufacturing method as the conventional method.
    According to the present invention, the device does not easily crack during driving unless the polarization state of the device is changed.
    权利要求:
    Claims (8)
    [1" claim-type="Currently amended] A piezoelectric transformer element comprising a piezoelectric plate made of a ceramic material and an input electrode and an output electrode formed on the piezoelectric plate to output a voltage from the output electrode when a voltage is applied to the input electrode.
    A portion of the piezoelectric plate having the same composition as the ceramic material forming the piezoelectric plate, wherein a reinforcement layer made of a ceramic material having a smaller particle size than the ceramic material after sintering concentrates tensile stress when the piezoelectric transformer element is driven. A piezoelectric transformer element selectively disposed on the phase.
    [2" claim-type="Currently amended] The method of claim 1,
    The piezoelectric plate is made of a ceramic material made of ceramic powder having a powder specific surface area of 2 m 2 / g,
    The reinforcing layer is a piezoelectric transformer element made of a ceramic material made of a ceramic powder having a powder specific surface area in the range of 3m 2 / g to 5m 2 / g.
    [3" claim-type="Currently amended] The method of claim 1,
    And the reinforcing layer is formed such that the width thereof in the longitudinal direction of the piezoelectric plate is 5% to 12% of the length of the piezoelectric plate.
    [4" claim-type="Currently amended] The method of claim 1,
    The piezoelectric plate is formed by laminating a plurality of ceramic sheets,
    The reinforcing layer is a piezoelectric transformer element is inserted into each gap between the plurality of ceramic sheets.
    [5" claim-type="Currently amended] The method of claim 1,
    Input portions each having an input electrode are disposed in the longitudinal direction on both side portions of the piezoelectric plate
    An output portion having an output electrode is formed substantially in the center portion in the longitudinal direction of the piezoelectric plate,
    The reinforcement layer is a piezoelectric transformer element formed in the longitudinal region including the output electrode.
    [6" claim-type="Currently amended] In the method of manufacturing a piezoelectric transformer element,
    Selectively in the required portion of each ceramic sheet forming the piezoelectric plate of the piezoelectric transformer element a reinforcing layer made of ceramic powder having the same composition as the ceramic sheet of the piezoelectric plate and having a larger powder specific surface area than the piezoelectric plate. Deploying, and
    Forming and sintering the ceramic sheet and the ceramic powder to produce the piezoelectric plate.
    Piezoelectric transformer device manufacturing method comprising a.
    [7" claim-type="Currently amended] The method of claim 6,
    A ceramic material having a powder specific surface area of 2 m 2 / g is used to form the ceramic sheet of the ceramic plate,
    Wherein a ceramic powder having a powder specific surface area in the range of 3 m 2 / g to 5 m 2 / g is used to form the reinforcing layer.
    [8" claim-type="Currently amended] The method of claim 6,
    And the reinforcing layer is formed by coating a surface of the ceramic sheet forming the piezoelectric plate to apply a ceramic paste.
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    同族专利:
    公开号 | 公开日
    US6140747A|2000-10-31|
    JPH11177158A|1999-07-02|
    JP3137063B2|2001-02-19|
    TW393789B|2000-06-11|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    1997-12-16|Priority to JP34619397A
    1997-12-16|Priority to JP97-346193
    1998-12-15|Application filed by 가네꼬 히사시, 닛본덴기 가부시끼가이샤
    1999-07-26|Publication of KR19990063075A
    2002-02-19|Application granted
    2002-02-19|Publication of KR100317892B1
    优先权:
    申请号 | 申请日 | 专利标题
    JP34619397A|JP3137063B2|1997-12-16|1997-12-16|Piezoelectric transformer element and manufacturing method thereof|
    JP97-346193|1997-12-16|
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