Murata Manufacturing Co., Ltd.

Hirozumi Ogawa

Masahiko Kimura

Akira Ando

Takuya Sawada

Kosuke Shiratsuyu

Koichi Hayashi

Shinichiro Kawada

Hiroyuki Hayashi

Yasunari Miwa

Tatsuya Yamaguchi

Hiroyuki Sumioka

A piezoelectric ceramic electronic component that includes a piezoelectric ceramic body including at least one piezoelectric ceramic layer; and a plurality of electrodes on a surface or inside of the piezoelectric ceramic body and arranged so that the at least one piezoelectric ceramic layer is sandwiched between adjacent electrodes of the plurality of electrodes. The at least one piezoelectric ceramic layer is a ceramic sintered body containing a potassium sodium niobate-based compound and Mn. When the at least one piezoelectric ceramic layer sandwiched between the adjacent electrodes is divided into three equal parts in a thickness direction to sequentially define a first region, a second region, and a third region between the adjacent electrodes, a second Mn concentration in the second region is higher than a first Mn concentration in the first region and a third Mn concentration in the third region.

Piezoelectric ceramic electronic component

A piezoelectric component that has a piezoelectric element including a piezoelectric ceramic layer and a sintered metal layer on at least a first main surface of the piezoelectric ceramic layer and containing a non-precious metal, and a protective layer containing an elastic body covering first and second opposed main surfaces of the piezoelectric element. The piezoelectric ceramic layer contains 90 mol % or more of a perovskite compound that contains niobium, an alkali metal, and oxygen. A thickness of the piezoelectric element is 100 &#x3bc;m or less.

Piezoelectric component, sensor, and actuator

A piezoelectric ceramic base member is formed of a bar shaped bismuth layer compound, and has main electrodes on two end surfaces in an oscillation direction, with connection electrodes at side-surface central portions of the piezoelectric ceramic base member electrically connected to the main electrodes through extraction conductors interposed therebetween, respectively. The oscillation and polarization directions are set in the same direction, and the piezoelectric ceramic base member is driven at a resonant frequency or at a frequency in the vicinity thereof. The crystal c axis is preferably oriented in a direction orthogonal to the polarization direction. The resonant actuator is able to obtain a high oscillation speed as it has a large mechanical quality factor Qm, and the oscillation is not disturbed by mechanical factors.

Resonant actuator

A piezoelectric ceramic whose resonance frequency temperature characteristic can be easily adjusted is provided. It contains first and second parts (and) which can be alternately stacked layers. The first and second parts (and) are each composed of a compound having a bismuth layer structure, such as a complex oxide containing at least Sr, Bi, and Nb, and have degrees of c-axis orientation different from each other. Since the resonance frequency temperature characteristics change according to the degree of orientation, the first and second parts (and) having different degrees of orientation are appropriately combined so that the resonance frequency temperature characteristics of the piezoelectric ceramic () as a whole is easily adjusted.

Piezoelectric ceramic and method for making the same, and piezoelectric resonator and method for making the same

A piezoelectric ceramic composition includes a bismuth layer compound containing at least Sr, Bi and Nb, e.g., (SrNd)BiNbO, as a main component and 2 parts by weight or less (excluding 0 part by weight), preferably 0.04 part by weight to 0.5 part by weight, of Cu in terms of CuO relative to 100 parts by weight of the main component. From the viewpoint of improvement in sinterability, 0.1 part by weight to 2 parts by weight of Mn in terms of MnCOrelative to 100 parts by weight of the main component is preferably contained. As a result, it is possible to obtain a piezoelectric ceramic composition resisting no deterioration in piezoelectricity even when a rapid temperature change occurs, and an advantageous piezoelectric component, such as a piezoelectric actuator or a piezoelectric resonator, manufactured using the piezoelectric ceramic composition.

Piezoelectric ceramic composition and piezoelectric component

A piezoelectric ceramic composition that is based on a layered bismuth compound composed of Sr, Bi, Nb, oxygen, contains an additional monovalent metallic element. The piezoelectric ceramic composition has an elevated Curie point, is highly reliable at higher temperatures, that is, minimizes the reduction in the piezoelectric effect, and is useful as a material for piezoelectric ceramic devices that contain little or no lead or lead compounds. The layered bismuth compound contains not more than about 0.125 mol and more than 0 mol of the monovalent metallic element for 1 mol of Nb.

Piezoelectric ceramic composition and piezoelectric ceramic device composed of same

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 ceramic powder of grains having a shape-anisotropy is mixed with a calcined or uncalcined (or both) powder of a ceramic raw material. A ceramic slurry containing the produced mixed powder, a solvent and a binder is prepared and the ceramic slurry is formed into a sheet. A laminate comprised of a plurality of the sheets laminated to each other is uniaxially pressed to form an oriented product in such a manner that the length of the laminate in the direction parallel to the pressing axis becomes larger than that before the pressing, and the area of a plane perpendicular to the pressing axis of the laminate becomes larger than that before the pressing. The oriented formed product is fired and sintered.

Method of producing ceramic

In a piezoelectric ceramic containing a bismuth layer compound containing Ca, Bi, Ti, and O, as a main component, the molar ratio of Ca to Bi to Ti in the bismuth layer compound, which is the main component, is represented by a:b:c and formulas 0.15&lE;a/c<0.25 and 3.5&lE;(2a&plus;3b)/c&lE;3.88 are satisfied.

Piezoelectric ceramic and piezoelectric ceramic element including the same

A piezoelectric ceramic composition includes a bismuth layered compound containing Sr, Bi, Nb and a metal element other than Bi having a valence of 3. The bismuth layered compound satisfies the relational expressions: 0.275<a/c<0.5; 0.9&lE;b/c&lE;1; 0<x/c&lE;0.175; and 0.5<(a&plus;3x/2)/c&lE;0.7, where a, b, c and x represent the molar fractions of Sr, Bi, Nb, and the metal element other than Bi having a valence of 3, respectively. Thus, a piezoelectric ceramic composition mainly containing a bismuth layered compound whose bismuth content is equal to or less than the stoichiometric value and not substantially containing lead and which can be advantageously used for piezoelectric ceramic elements exhibiting a Q -factor sufficient for practical use can be achieved.

Piezoelectric ceramic composition and piezoelectric ceramic element using the same

A piezoelectric device having an electromechanical coefficient, which can be applied to practical uses, is obtained by an energy-trapping effect using a piezoelectric ceramic having a layered perovskite structure provided with high-temperature resistance and little high-frequency loss. The piezoelectric device has a substrate formed of a piezoelectric ceramic having a layered perovskite structure. The c-axis in the substrate is preferentially oriented in the width direction thereof, and the substrate is polarized in the longitudinal direction. Two electrodes are formed on both main surfaces of the substrate so as to oppose each other in the vicinity of the central part thereof. As a material used for the substrate, a piezoelectric ceramic composition primarily composed of a ceramic composition represented by the general formula CaBi Ti O is preferably used.

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Yasu, Japan

Hirozumi Ogawa