Abstract: A ceramic composition (sample) includes CaBi4Ti4O15 or another compound having a layered perovskite crystal structures and exhibiting ferroelectricity at ordinary temperature. The ceramic composition (sample) is then heated to a temperature higher than the melting point of the ceramic composition to make the ceramic composition molten or semi-molten. The ceramic composition is then annealed and solidified to yield a grain oriented ceramic (porcelain). This process can produce grain oriented ceramics from ceramic compositions mainly containing a compound having a layered perovskite crystal structure, and can improve electromechanical coefficients of piezoelectric ceramics containing a compound having a layered perovskite crystal structure.

Abstract: 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.

Abstract: 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 WO3 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.

Abstract: A lead-free piezoelectric ceramic composition is composed of a main component represented by the general formula (Sr1−xM1x)Bi2(Nb1−yWy)2O9, wherein M1 is one of divalent metals other than Sr and trivalent metals other than Bi, 0<x≦0.3, and 0<y≦0.3. Examples of the divalent metals and trivalent metals include Ca, Ba, Mg, La, Ce, Pr, Nd, Sm, Gd, Dy, Er, Yb, Sc and Y. The piezoelectric ceramic composition can be sintered at a relatively low temperature of 1,100° C. or less, and has an electromechanical coupling coefficient kt which is at a practical level. The piezoelectric ceramic composition may be used in piezoelectric ceramic filters, piezoelectric ceramic oscillators and piezoelectric ceramic vibrators.

Abstract: A piezoelectric ceramic composition is composed of a main component represented by the general formula (Ca1-xM1x)Bi4Ti4O15 wherein M1 is one of divalent metals other than Ca and trivalent metals other than Bi, and 0<x≦0.45, and manganese as an auxiliary component in an amount of more than 0 to not more than about 1.5 percent by weight as MnCO3. Examples of the divalent metals and trivalent metals include Sr, Ba, Mg, La, Ce, Pr, Nd, Sm, Gd, Dy, Er, Yb, Sc and Y. The piezoelectric ceramic composition has an electromechanical coupling coefficient kt of at least 10%, which a practical level. The piezoelectric ceramic composition may be used in piezoelectric ceramic filters, piezoelectric ceramic oscillators and piezoelectric ceramic vibrators.

Abstract: The semiconducting ceramic material of the present invention containing BaTiO3 and having a positive temperature coefficient of resistance is endowed with high withstand voltage. In the semiconducting ceramic material, a boundary temperature defined at the boundary between a first temperature range and a second temperature range is 180° C. or more (e.g., 370° C.) higher than the Curie temperature, wherein the first temperature range is higher than the Curie temperature and the ceramic material has a positive temperature coefficient of resistance in the range, and the second temperature range is higher than the first temperature range and the ceramic material has a negative temperature coefficient of resistance in the range.

Abstract: A piezoelectric element has a very small size, has a high coefficient of electromechanical coupling, and can easily be impedance-matched to a circuit. An interdigital electrode, including two comb-shaped electrodes, is provided on one surface of a plate-like piezoelectric member, and similarly, an interdigital electrode, including two comb-shaped electrodes, is provided on another surface of the plate-like piezoelectric member. The piezoelectric member is polarized by applying electrical fields between the two respective pairs of comb-shaped electrodes; and in addition, by applying an electrical field for excitation between a terminal connecting one of the comb-shaped electrodes to each interdigital electrode, and another terminal connecting the other comb-shaped electrodes to each interdigital electrode, longitudinal vibrations in a stiffened mode are excited, whereby the piezoelectric member expands and contracts in the longitudinal direction thereof.

Abstract: A surface acoustic wave device includes a piezoelectric substrate, and an interdigital transducer provided on the piezoelectric substrate, wherein the piezoelectric substrate includes at least two piezoelectric ceramic layers made of a polycrystalline material. The at least two piezoelectric ceramic layers are stacked so that electrical characteristics and mechanical characteristics thereof vary in a direction that is substantially perpendicular a surface of the piezoelectric substrate upon which the at least two ceramic piezoelectric layers are stacked.

Abstract: A piezoelectric ceramic composition which contains a ceramic compound and manganese. The ceramic compound serves as a primary component and is represented by formula (Sr.sub.1-x M.sub.x)Bi.sub.2 Nb.sub.2 O.sub.9. In the formula, M represents a divalent metal element and x satisfies 0.ltoreq.x.ltoreq.0.3. Manganese is contained in an amount of 1.0 wt. % or less (0 being excluded) as MnCO.sub.3.

Abstract: Provided is a piezoelectric ceramic composition containing a lead titanate which has excellent temperature stability of the resonance frequency, and is suitable for application in a filter, a vibrator or the like, and a piezoelectric element using the piezoelectric ceramic composition. A piezoelectric substrate comprising a ceramic material containing PbTiO.sub.3 is provided with vibrating electrodes on the front and rear surfaces. The ceramic material containing PbTiO.sub.3 contains not less than about 0.1% by weight or more than about 3.0% by weight of Mn based on MnCO.sub.3 as the subcomponent in the main component having a composition satisfying 0.02.ltoreq.x.ltoreq.0.16 and 0.15.ltoreq.y.ltoreq.0.50 of the general formula Pb.sub.1-1.5x Nd.sub.x [(In.sub.1/2 Nb.sub.1/2).sub.y Ti.sub.1-y ]O.sub.3.

Abstract: The present invention provides a piezoelectric ceramic composition which predominantly comprises a composition represented by the following formula :(1-n)(K.sub.1-x-y Na.sub.x Li.sub.y).sub.m (Nb.sub.1-z Ta.sub.z)O.sub.3 -nM1M2O.sub.3wherein M1 represents a divalent metal element such as Mg, Ca, Sr or Ba; M2 represents a tetravalent metal element such as Ti, Zr, Sn or Hf; and x, y, z, m, and n satisfy the following conditions: 0.9.ltoreq.X; y.ltoreq.0.3; x+y<0.75; 0.ltoreq.z.ltoreq.0.3; 0.98.ltoreq.m.ltoreq.1.0; and 0<n<0.1.

Abstract: The present invention provides a piezoelectric ceramic composition which predominantly comprises a composition represented by the following formula :(1-n)(K.sub.1-x-y Na.sub.x Li.sub.y) .sub.m (Nb.sub.1-z Ta.sub.z)O.sub.3 -nM1M2M3O.sub.3wherein M1 represents a trivalent metal element such as Bi; M2 represents a monovalent metal element such as K, Na or Li; M3 represents a tetravalent metal element such as Ti, Zr, Sn or Hf; and x, y, z, m, and n satisfy the following conditions: 0.9.ltoreq.x; y.ltoreq.0.3; x+y<0.75; 0.ltoreq.z.ltoreq.0.3; 0.98.ltoreq.m.ltoreq.1.0; and 0<n<0.1.

Abstract: A piezoelectric transformer has a plate shaped piezoelectric member including a driving section disposed at one portion of the piezoelectric member including one end thereof and a power-generating section at the other portion of the piezoelectric member including the other end thereof. The driving section includes driving electrodes and a portion of the piezoelectric member which is polarized in the thickness direction. The power-generating section includes a power-generating electrode and a portion of the piezoelectric member polarized in the longitudinal direction. At least one polarization electrode which is exposed in part on a surface of the piezoelectric member is provided between the driving section and the power-generating electrode.

Abstract: The present invention provides a piezoelectric ceramic having a low mechanical quality coefficient Qm and excellent heat resistance, for example, a piezoelectric ceramic for a filter element which can be applied to surface mounting. The piezoelectric ceramic contains at least a composite oxide of lead, zirconium and titanium, and oxides of manganese, silicon and boron, the concentration of the manganese oxide present in the crystal gain boundary being higher than that in crystal grains of the piezoelectric ceramic.

Abstract: There is provided a piezoelectric ceramic having a small mechanical factor of merit Qm and excellent heat-resisting properties, e.g., a piezoelectric ceramic for filter elements which is compatible with surface mounting and a method of manufacturing the same in a large amount and in a stable manner. There is provided a piezoelectric ceramic which is a composite oxide of at least lead, zirconium and titanium, wherein an oxide of manganese exists in a grain boundary layer in a density higher than that in a crystal grain of the piezoelectric ceramic and a glass phase exists in the grain boundary layer. It is manufactured by depositing a manganese compound and a glass material on the surface of a piezoelectric ceramic comprising a composite oxide of at least lead, zirconium and titanium and by performing thermal processing thereafter to diffuse the deposited substance in a grain boundary portion of the piezoelectric ceramic.

Abstract: A piezoelectric transformer includes a plate-shaped piezoelectric member having a driving section located at a first portion of the piezoelectric member including a first end and a power-generating section located at a second portion of the piezoelectric member including a second end. The driving section is made by repeatedly and alternately laminating a driving electrode and a portion of the piezoelectric member which is polarized in the thickness direction. The power-generating section includes a power-generating electrode and a portion of the piezoelectric member which is polarized in the longitudinal direction. In the piezoelectric transformer, at least one of the driving section and the power-generating section has an area which is near a boundary between the driving section and the power-generating section which has a lower degree of polarization than the degree of polarization in areas spaced away from the boundary between the driving section and the power-generating section.

Abstract: Improved are the piezoelectric characteristics of conventional ceramics of (Ba.sub.1-x Sr.sub.x).sub.2 NaNb.sub.5 O.sub.15 where 0.ltoreq.x.ltoreq.1, and provided is a novel piezoelectric ceramic composition which does not contain lead and which can be practiced industrially as a material for piezoelectric ceramic devices such as piezoelectric ceramic filters, etc. The piezoelectric ceramic composition comprises, as the essential component, a ceramic component of the general formula, (1-y)(Ba.sub.1-x Sr.sub.x)Nb.sub.2 O.sub.6 --yNaNbO.sub.3 where 0.ltoreq.x.ltoreq.1 and 0.15.ltoreq.y<1/3. Preferably, the composition contains, as the side component, at least one oxides of Mn, Cr, W, Si, Mo, Ni, Co, Sn, Mg, Sb, Ti, Zr and Fe, in a total amount of not larger than about 5% by weight in terms of MnO.sub.2, Cr.sub.2 O.sub.3, WO.sub.3, SiO.sub.2, MoO.sub.3, NiO, Co.sub.2 O.sub.3, SnO.sub.2, MgO, Sb.sub.2 O.sub.3, TiO.sub.2, ZrO.sub.2 and Fe.sub.2 O.sub.3, respectively.

Abstract: A Mo side component is added to the essential component of a piezoelectric ceramic composition containing Pb, Zr, Ti and O, in an amount of from about 0.06% by weight to about 5.0% by weight, in terms of MoO.sub.3, relative to the amount of the essential component. Preferably, the side component is added to the calcined essential component, and the resulting mixture is fired to give a sintered piezoelectric ceramic composition. The addition of the side component improves the low-temperature sinterability of the piezoelectric ceramic composition without worsening the piezoelectric characteristics of the composition.

Abstract: Disclosed are piezoelectric ceramic compositions comprising, as the essential component, (Na.sub.0.5 Bi.sub.0.5)Bi.sub.4 Ti.sub.4 O.sub.15, or (Na.sub.0.5 Bi.sub.0.5).sub.1-x M.sub.x Bi.sub.4 Ti.sub.4 O.sub.15 where M is at least one divalent metal element or (A1.sub.0.5 A2.sub.0.5) and A1 is at least one monovalent metal element, A2 is at least one trivalent metal element, and 0<x.ltoreq.0.5, and, as the side component, manganese in an amount of from about 0.7 to 3.0% by weight, relative to the essential component and in terms of MnCO.sub.3. The compositions have a piezoelectric constant, d.sub.33, of not smaller than 25 pC/N at temperatures above 500.degree. C.

Abstract: A piezoelectric transformer has a plate shaped piezoelectric member including a driving section disposed at one portion of the piezoelectric member including one end thereof and a power-generating section at the other portion of the piezoelectric member including the other end thereof. The driving section includes driving electrodes and a portion of the piezoelectric member which is polarized in the thickness direction. The power-generating section includes a power-generating electrode and a portion of the piezoelectric member polarized in the longitudinal direction. At least one polarization electrode which is exposed in part on a surface of the piezoelectric member is provided between the driving section and the power-generating electrode.