Murata Manufacturing Co., Ltd.

Koichi Hayashi

Akira Ando

Masahiko Kimura

Takuya Sawada

Atsushi Yamamoto

Shozo Kobayashi

Hiroshi Takagi

Akira Nagai

Kiyoshi Hase

Koji Ogiso

Yu Tokuda

Shinji Omura

Yoichi Deguchi

Akihiro Nakamichi

Shigeharu Kasai

Hidekiyo Takaoka

Shizuharu Watanabe

Katsuhiro Horikawa

Hirozumi Ogawa

Hiromitsu Hongo

Toshikatsu Hisaki

Isamu Yoshizawa

Junichi Nomura

Shodo Takei

Seishiro Goto

Masanori Kimura

Satoshi Shindo

Satoshi Shindou

Megumi Otsuka

Yuji Yoshikawa

Yasuhiro Morimoto

A driving device that causes a movable body to move stably with minimal backward movement. The driving device includes a plate-shaped driving unit with an elastic body and a piezoelectric element joined to a main surface of the elastic body. Moreover, the movable body is disposed into a cavity of the elastic body and is moved by being pitch fed when the driving unit is driven. The driving unit vibrates with flexural vibration and one more other vibration modes or with vibration of a coupled mode in which the flexural vibration and the other vibration mode are coupled with each other.

Driving device

In a multilayer piezoelectric actuator, external electrodes are formed on external surfaces of a multilayer piezoelectric body in which a plurality of internal electrodes and a plurality of piezoelectric layers are stacked on top of one another. Each of the external electrodes includes a base electrode and a stress-absorbing external-electrode member formed on the base electrode. The stress-absorbing external-electrode member is provided with an elastically deformable elastic structure, and a planar portion, which is continuous with the elastic structure and has at least an area sufficient for bonding a feeder terminal such as a lead line thereto.

Multilayer peiezoelectric actuator having a stress-absorbing external-electrode member with portions thereof not bonded to a base electrode

A monolithic piezoelectric element includes an element assembly in which internal electrode layers and piezoelectric ceramic layers are laminated alternately. The internal electrode layers contain an Ag&#x2014;Pd alloy, which has an Ag content of 85 percent by weight or more as a primary component, a metal element having a valence of at least one of pentavalence or hexavalence. The piezoelectric ceramic layers contain a composite oxide represented by Pb(Ti,Zr)Oas a primary component, a part of Ag contained in the internal electrode layers is almost uniformly diffused therein and, the metal element is diffused in the form of a metal oxide in such a way that the concentration is reduced with decreasing proximity to the internal electrode layers. In this manner, a monolithic piezoelectric element having a desired large piezoelectric constant can be obtained without inviting an increase in cost even when a firing treatment is conducted at low temperatures.

Monolithic piezoelectric element

A piezoelectric actuator includes external conductors formed on an outer surface of a piezoelectric component. The external conductors each include a thick-film conductor and a conductive reinforcer. The thick-film conductor is provided with a first thick-film conductor formed on the outer surface of the piezoelectric component, second thick-film conductors which are formed on part of an outer surface of the first thick-film conductor and which are in surface-contact with the outer surface of the first thick-film conductor. The conductive reinforcer is attached to outer surfaces of the second thick-film conductors.

Piezoelectric actuator

In a method for manufacturing a piezoelectric actuator, a ceramic sintered body is prepared and a size of the ceramic sintered body is adjusted in a thickness direction defined below by grinding piezoelectric ceramic layers, included in the ceramic sintered body, located outermost in the thickness direction. In the ceramic sintered body, internal electrodes are each disposed between piezoelectric ceramic layers. The thickness direction is defined as the direction along the thickness of the piezoelectric ceramic layer. Each of the inert sections are disposed on at least one side of the active section, for driving the piezoelectric actuator, in the thickness direction. Dummy internal electrodes are arranged in the inert sections such that each of the dummy internal electrodes are each located between ceramic layers. The thickness of the piezoelectric ceramic layers disposed between the dummy internal electrodes increases with distance from the active section.

Piezoelectric actuator and method for manufacturing piezoelectric actuator

A multilayer piezoelectric device including a body having internal electrode layers and piezoelectric ceramic layers alternately stacked. The internal electrode layers contain Cu as a major component, the piezoelectric ceramic layers contain a compound oxide represented by Pb(Ti, Zr)Oas a major component, and a metal oxide (NbO, SbO, TaO, or WO) containing Nb, Sb, Ta, or W, which is at least one of a pentavalent metal element and a hexavalent metal element, is incorporated in the piezoelectric ceramic layers such that the concentration of the metal oxide decreases with distance from the internal electrode layers. Thereby, even in a case where internal electrodes contain Cu as a major component, it is possible to provide a multilayer piezoelectric device which can be obtained by low-temperature firing while ensuring a sufficient piezoelectric constant.

Laminated piezoelectric element and process for producing the same

A piezoelectric device is formed by simultaneously firing a piezoelectric ceramic mainly composed of a perovskite complex oxide represented by general formula ABOand electrodes mainly composed of copper. The piezoelectric ceramic is represented by PbMe[(MM)TiZr]O(wherein Me represe element, Mis an acceptor element which is a divalent metal element, and Mis a donor element which is a pentavalent metal element), and satisfies equations 0.05&#x2266;z&#x2266;0.40, 0&#x3c;bz/3&#x2266;0.035, 0.345&#x2266;x&#x2266;0.480, 0.965&#x2266;&#x3b1;&#x2266;1.020, and 0&#x2266;a&#x2266;0.05. In other words, the B sites contain excessive donors, and thus a piezoelectric device having good piezoelectric characteristics can be obtained even in the cases where a base metal material mainly composed of inexpensive copper is used as the internal electrode material.

Piezoelectric device

A monolithic piezoelectric element includes a stack, and the stack includes a crack-forming conductive layer arranged to intentionally form a small crack in the stack. The small crack alleviates stress, thereby preventing the occurrence of a large crack that may extend to the piezoelectrically active region.

Method for manufacturing piezoelectric actuator

A piezoelectric ceramic composition has the composition formula (PbMe){(NiZnNb)TiZr}O, wherein Me represents at least one element selected from the group consisting of Ba, Sr and Ca; a, b, d, and x satisfy the inequalities 0.975&#x2266;a&#x2266;0.998, 0&#x2266;b&#x2266;0.05, 1&#x3c;d&#x2266;1.3, and 0.39&#x2266;x&#x2266;0.47; and c and z are located in a region surrounded by lines connecting Point A (z=0.25, c=0.1), Point B (z=0.25, c=0.85), Point C (z=0.1, c=0.6), Point D (z=0.075, c=0.5), Point E (z=0.05, c=0.2), and Point F (z=0.05, c=0.1) or located on the lines in the z-c plane. Therefore, the piezoelectric ceramic composition is effective in achieving a large piezoelectric constant, a small dielectric constant, and a high Curie point. A piezoelectric actuator contains the piezoelectric ceramic composition.

Piezoelectric ceramic composition and piezoelectric actuator

A piezoelectric element contains a piezoelectric ceramic body having a layered perovskite structure, and has the C axis selected and oriented in the thickness direction. In the piezoelectric ceramic body, line shaped electrodes are formed perpendicular to the C axis selected and oriented. The electrodes exposed at both of the end faces of the piezoelectric ceramic body are covered with conductive materials and insulation materials. The piezoelectric ceramic body is polarized in the opposite directions on both of the sides of electrodes arranged in the width direction. Moreover, external electrodes are formed on the faces where the conductive materials and the insulation materials are formed, whereby two groups of the electrodes are arranged in an interdigital electrode form.

Method of producing a piezoelectric element

A laminate type piezoelectric element having an improved piezoelectric property is provided. Vibration electrodes are arranged in a piezoelectric body, and high-order vibration of the thickness vibration is excited. The piezoelectric ceramic includes two ceramic piezoelectric layers which are laminated, and are integrally formed. Each of the ceramic piezoelectric layers contains ceramic crystal grains having shape anisotropy and spontaneous polarization preferentially oriented in one plane. The in-plane direction of this plane is perpendicular to the principal surfaces of the ceramic piezoelectric layers. The ceramic piezoelectric layers are polarized in the same thickness direction.

Piezoelectric element and method for manufacturing the same

A feedback circuit and amplifiers using a vibrator comprising a piezoelectric body having a bismuth layered compound as the main ingredient thereof are provided so as to generate oscillation. Load capacitors comprising the feedback circuit together with the vibrator are formed. These load capacitors each have, as the main ingredient thereof, a dielectric body which decreases in the relative dielectric constant with the increase in temperature in the region not less than one half the temperature range from &minus;20 to 80&deg; C., and in which the &egr;-TC is not less than 5000 ppm/&deg; C., wherein the &egr;-TC is an average change rate of the relative dielectric constant in the above-described temperature range and is represented by (Cmax&minus;Cmin)/(C &middot;100), where Cmax is the maximum value of capacitance in the above-described temperature range, Cmin is the minimum value of capacitance in the above-described temperature range, and C is the capacitance at 20&deg; C.

Oscillator and production method therefor

A piezoelectric ceramic for producing a piezoelectric element having sufficient strength and hardness in spite of compactness is provided. The piezoelectric ceramic contains lead titanate as a primary component and about 0.1 to 5% by weight of tungsten in terms of WO relative to the primary component, and about 75% or more of crystal particles constituting the piezoelectric ceramic have particle diameters distributed in the range of about 0.2 &mgr;m to 0.8 &mgr;m.

Piezoelectric ceramic and manufacturing method therefor

A piezoelectric ceramic composition capable of obtaining a piezoelectric member that can provide a sufficient sintering density even by firing at a low temperature besides only allowing small amount of Pb to be evaporated by firing to reduce deterioration of electrical characteristics, wherein the piezoelectric member comprises a perovskite structure oxide of the piezoelectric ceramic composition containing Pb, Ti, Zr, Ma (Ma represents at least one of Cr, Mn, Fe and Co) and Md (Md represents at least one of Nb, Sb, Ta and W), and wherein a represents the total content (in mole) of Ma, and b, c, d and e (in mole) represent the contents of Sb, Nb, Ta and W, respectively, and 0.50<a/(b&plus;c&plus;d&plus;2e).

Method for manufacturing piezoelectric ceramic composition, piezoelectric resonator, piezoelectric transformer and piezoelectric actuator, and piezoelectric laminated sintered body

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Koichi Hayashi