Abstract: A method for producing an energy trap piezoelectric resonator which operates in a thickness longitudinal vibration mode and which includes a piezoelectric member and first and second vibrating electrodes disposed on respective major surfaces of the piezoelectric member, involves the use of a piezoelectric material having an R value and an A value which are selected such that Qe=C/(R×A), where R and A are the average pore size in micrometers and the porosity in percent of the piezoelectric member, respectively. Here, Qe is a value at a frequency to be used and C is a constant that is determined by the piezoelectric material of the piezoelectric member. An energy trap, thickness longitudinal piezoelectric resonator produced by this method has a sufficiently high response to a vibration mode to be used, without any limitation on the type of piezoelectric material and size of the piezoelectric member and the frequency to be used.

Abstract: A piezoelectric ceramic composition is provided, which includes a ceramic composition expressed by a general formula: Sr1-x-yM1xM2yBi2(Nb1-aTaa)2-zTizO9, wherein M1 is at least one element selected from the group consisting of Ca and Ba, M2 is at least one element selected from the group consisting of La, Y, Dy, Er, Yb, Pr, Nd, Sm, Eu and Gd, and x, y, z and a in the general formula respectively are in the range of 0.0≦x<0.9, 0.0<y<0.3, 0.0≦z<0.3, and 0.0≦a≦1.0. This makes it possible to provide a piezoelectric ceramic composition that is free of lead and has a larger electromechanical coupling factor than a conventional bismuth layered compound, and a piezoelectric element using the same.

Abstract: A valve system having a valve operated by a piezoelectric device to control the flow of fluid through the valve system. Movement of the valve is controlled by a pre-stressed bender actuator that changes its shape by deforming in opposite axial directions in response to a control signal applied by an actuator control system. The valve system may comprise a common rail fuel injector, electrohydraulic actuator system, electronically-controlled fuel injector, gasoline port injector, fluid metering valve, relief valve, reducing valve, direct valve or direct-injection gasoline injector.

Abstract: 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≦b/c≦1; 0<x/c≦0.175; and 0.5<(a+3x/2)/c≦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 Qmax-factor sufficient for practical use can be achieved.

Abstract: A valve system having a valve operated by a piezoelectric device to control the flow of fluid through the valve system. Movement of the valve is controlled by a pre-stressed bender actuator that changes its shape by deforming in opposite axial directions in response to a control signal applied by an actuator control system. The valve system may comprise a common rail fuel injector, electrohydraulic actuator system, electronically-controlled fuel injector, gasoline port injector, fluid metering valve, relief valve, reducing valve, direct valve or direct-injection gasoline injector.

Abstract: The invention relates to a micro-reactor, which is preferably configured as a plate and preferably consists of silicon. The aim of the invention is to improve the blending of the substances that are to react. To achieve this, the reactor is provided with a mechanic coupling, comprising at least one generator of mechanical oscillations (24). The invention also relates to a device (25) for controlling the temperature of the micro-reactor.

Abstract: A piezoelectric resonator is constructed to be vibrated in a square type vibration mode and to minimize the variations in the resonant frequency caused by the manufacturing process. The resonator includes a piezoelectric substrate having a pair of main surfaces, electrodes disposed on the pair of main surfaces and grooves provided on one of the main surfaces of the piezoelectric substrate. The grooves divide at least one of the electrodes into a plurality of divided electrodes. One of the plurality of divided electrodes defines an input/output electrode. A maximum distance between the outer edges of two of the grooves disposed opposite to each other across the input/output electrode is about 0.5 to about 0.55 times the length of one side edge of the piezoelectric substrate.

Abstract: A valve system having a valve operated by a piezoelectric device to control the flow of fluid through the valve system. Movement of the valve is controlled by a pre-stressed bender actuator that changes its shape by deforming in opposite axial directions in response to a control signal applied by an actuator control system. The valve system may comprise a common rail fuel injector, electrohydraulic actuator system, electronically-controlled fuel injector, gasoline port injector, fluid metering valve, relief valve, reducing valve, direct valve or direct-injection gasoline injector.

Abstract: A valve system having a valve operated by a piezoelectric device to control the flow of fluid through the valve system. Movement of the valve is controlled by a pre-stressed bender actuator that changes its shape by deforming in opposite axial directions in response to a control signal applied by an actuator control system. The valve system may comprise a common rail fuel injector, electrohydraulic actuator system, electronically-controlled fuel injector, gasoline port injector, fluid metering valve, relief valve, reducing valve, direct valve or direct-injection gasoline injector.

Abstract: The present invention provides a megasonic cleaning apparatus configured to provide effective cleaning of a substrate without causing damage to the substrate. The apparatus includes a probe having one of a variety of cross-sections configured to decrease the ratio of normal-incident waves to shallow-angle waves. One such cross-section includes a channel running along a portion of the lower edge of the probe. Another cross-section includes a narrow lower edge of the probe. Another cross-section is elliptical. Another cross-section includes transverse bores originating in the lower edge of the probe. As an alternative to, or in addition to, providing a probe having a cross-section other than circular, the present invention may also provide a probe having a roughened lower surface.

Abstract: A valve system having a valve operated by a piezoelectric device to control the flow of fluid through the valve system. Movement of the valve is controlled by a pre-stressed bender actuator that changes its shape by deforming in opposite axial directions in response to a control signal applied by an actuator control system. The valve system may comprise a common rail fuel injector, electrohydraulic actuator system, electronically-controlled fuel injector, gasoline port injector, fluid metering valve, relief valve, reducing valve, direct valve or direct-injection gasoline injector.

Abstract: A piezoelectric/electrostrictive device includes a pair of mutually opposing thin plate sections made of metal and a fixation section for supporting the thin plate sections. One or more piezoelectric/electrostrictive elements are arranged on at least one thin plate section of the pair of thin plate sections. An object is attached to forward end portions of the pair of thin plate sections. An areal size of a surface of the object interposed between the thin plate sections is larger than an areal size of an object attachment surface of the thin plate sections.

Abstract: The present invention provides a composite vibrator that can maintain high sensitivity even when miniaturized. The composite vibrator includes tuning bar vibrators having the same length and support members for supporting the tuning bar vibrators. The tuning bar vibrators are arranged in a direction orthogonal to the longitudinal direction to be coupled with each other near nodes of bending vibrations occurring at both free ends of the tuning bar vibrators. In this arrangement, since the tuning bar vibrators are coupled with each other, the mass of the composite vibrator increases. Thus, even when the length of the longitudinal direction of the tuning bar vibrator is reduced, due to the increased mass, higher sensitivity for the detection of an angular velocity can be obtained.

Abstract: A piezoelectric element includes a piezoelectric substrate formed of a piezoelectric material and a pair of electrodes formed on a first principal plane and a second principal plane of the piezoelectric substrate, wherein thickness shear vibration occurs, and the vibration direction of the thickness shear vibration is nonparallel to the side walls of the piezoelectric substrate.

Abstract: The present invention provides a piezoelectric vibrator, in which there is no significant change in the characteristics even when depole occurs due to heat shock and the like. The piezoelectric vibrator includes a first piezoelectric substrate having split electrodes formed on one main surface thereof and a second piezoelectric substrate having a common electrode formed on one main surface thereof. The remaining main surfaces of both piezoelectric substrates are bonded to each other via an intermediate electrode. The material of the first piezoelectric substrate differs from the material of the second piezoelectric substrate. As a result, the difference (longitudinal DF) between a resonant frequency and an anti-resonant frequency in a longitudinal vibration of the piezoelectric vibrator substantially coincides with the difference (transverse DF) between a resonant frequency and an anti-resonant frequency in a transverse vibration thereof.

Abstract: A ladder-type piezoelectric filter includes two parallel resonators adapted to vibrate in a square type vibration mode, each of which has a substantially square shape, and two series resonators adapted to vibrate in a square type vibration mode, each of which has a substantially square shape and has a corner cut portion located at each of four corners. The parallel and series resonators have substantially equal distances between respective opposite side edges thereof and are made from materials having the same frequency constant. The parallel and series resonators are housed within a housing and are aligned at approximate centers thereof.

Abstract: An object of the present invention is to provide a quartz resonator unit and a quartz oscillator having a small size and a light weight and having the capability of oscillating in the overtone mode, and also to provide a quartz element for use in the quartz resonator unit and quartz oscillator. Thus, a further object is to determine the optimum width-to-thickness ratio of the quartz element at which the quartz element having a width less than 1.5 mm and a length less than 4.7 mm does not show coupling with spurious vibrations over the entire range of operation temperature. From the experiments and evaluation performed repeatedly, it has been concluded that an AT-cut rectangular quartz element having the width-to-thickness ratio w/t in a range selected from the group consisting of 8.48 0.05, 12.18+/−0.05, 13.22+/−0.07, 14.78+/−0.07, and 15.57 0.07 is suitable as a small-sized quartz element that can oscillate at a high frequency and has excellent temperature characteristics.

Abstract: A surface mounting quartz-crystal oscillator having a container body formed with a recess of which a pair of opposite sidewalls are provided with steps, a quartz blank, an IC (integrated circuit) chip constituting an oscillating circuit including a quartz crystal member made of the quartz blank, and a cover closing the container body for sealing the quartz blank and the IC chip within the container body. At least one of the both ends of the quartz blank is bonded to the bottom face of the recess, and the opposite ends of the IC chip are held to the steps. A space is defined between the IC chip and the bottom face of the recess for permitting at least a part of the quartz blank to be disposed in the space.

Abstract: A laminated piezoelectric transformer according to the present invention comprises (a) a laminated body formed by laminating a plurality of ceramic layers and a plurality of internal electrodes and (b) a plurality of external electrodes electrically connected with the internal electrodes and disposed on the surface of the laminated body. Further, the internal electrodes of the laminated piezoelectric transformer of the invention are characterized by having a plurality of primary internal electrodes positioned at the middle portion along the longitudinal direction of the laminated body and a plurality of secondary internal electrodes positioned at both end portions of the laminated body. By virtue of this configuration of the invention, the polarization volume on the secondary side can be enlarged and, therefore, the laminated piezoelectric transformer of the invention can step up voltages at high energy conversion efficiency.

Abstract: An electroacoustic transducer includes a diaphragm including a substantially rectangular metal plate and a substantially rectangular piezoelectric plate having electrodes on an upper surface and a lower surface thereof, with one of the electrodes being connected to the metal plate. A support medium including retaining parts for retaining two shorter sides of the diaphragm is provided. The shorter sides of the diaphragm are fixed to the retaining parts by an adhesive having a Young's Modulus after curing that is between about 4.0×104 N/m2 and about 5.0×106 N/m2. Gaps between the two longer sides of the diaphragm and the support member are sealed by an elastic sealant. The diaphragm is arranged to undergo bending vibration in a longitudinal bending mode by applying a predetermined electrical signal between the metal plate and the opposing electrode provided on the piezoelectric plate.

Abstract: A piezoelectric substrate is constituted by a piezoelectric material of an effective Poisson's ratio being less than 1/3. The substrate has a pair of opposite faces and the opposite faces are provide with a pair of vibrating electrodes in correspondence. The opposite faces of the piezoelectric substrate are rectangular respectively. The sum of the lengths Lc of the one faces in the opposite faces 1a, 1b and the length Wc of the other side of the same is limited within range 2.22 mm≦≦2.24 mm or 2.34 mm≦≦2.48 mm, said one faces being vertical each other. The areas Sc of the opposite faces are 1.22 mm2≦Sc≦1.26 mm2 or 1.35 mm2≦Sc≦1.538 mm2. Accordingly, though using the piezoelectric material of the effective Poisson's ratio being less than 1/3, vibration in the thickness extensional fundamental waves can be steadily utilized.

Abstract: A piezoelectric ceramic material which can suppress segregation of a W compound or a W oxide in W-containing sintered PbTiO3 and a piezoelectric transducer employing the ceramic material. The ceramic material contains lead titanate as a primary component; an Mn-containing oxide or an Mn-containing compound and a W-containing compound or a W-containing oxide as secondary components; and an Si-containing oxide or an Si-containing compound as an additional component. Alternatively, the piezoelectric ceramic material contains a primary component containing PbTiO3 and Pb(MnyW(1−y))O3 and additionally SiO2 or PbSiO3.

Abstract: A piezoelectric device operable to excite a thickness extensional third harmonic vibration is provided, which can realize a high performance oscillator with an excellent thermal stability. The piezoelectric device includes a piezoelectric substrate. The piezoelectric substrate is formed from a piezoelectric material containing as major components Sr, Bi, Nb, and O. Vibration electrodes are formed on both of the surfaces of the piezoelectric substrate. The range lying between the vibration electrodes and defined by the overlapped vibration electrodes constitutes an energy trapping range. The value L/t is set to be less than 9, in which L represents the length of the longest secant extending between intersections on the periphery of the energy confining region and t represents the distance between the vibration electrodes.

Abstract: An energy-trapping piezoelectric vibration device generates a thickness shear mode and includes an elongated piezoelectric element having first and second longitudinally opposed ends, top and bottom surfaces provided between the first and second ends such that the top and bottom surfaces oppose each other, and beveled surfaces disposed at a vicinity of the first and second ends such that the thickness of the piezoelectric element gradually decreases towards the first and second ends, respectively. First and second vibration electrodes are disposed on the top surface and the bottom surface of the piezoelectric element, respectively. The first and second vibration electrodes are located at an approximate middle portion of the piezoelectric element so as to oppose each other with the piezoelectric element disposed therebetween, to define opposing portions which constitute a vibrator.

Abstract: A piezoelectric/electrostrictive device includes: a driving portion which is driven by displacement of a piezo-electric/electrostrictive element, a movable portion which operates on the basis of a drive of the driving portion, and a fixed portion for supporting the above driving portion and movable portion. It has a driving portion including thin plates facing each other and a thin film piezoelectric/electrostrictive element formed on the surface of at least one of the thin plates, and the above fixed portion and the above movable portion are joined by the driving portion. In this piezoelectric/electrostrictive element, the movable portion can largely be displaced, and it is not easily affected by a harmful vibration in operation, and it is excellent in mechanical strength, handling efficiency, impact resistance, and moisture resistance.

Abstract: A piezoelectric resonator is constructed to be vibrated in a square type vibration mode and to minimize the variations in the resonant frequency caused by the manufacturing process. The resonator includes a piezoelectric substrate having a pair of main surfaces, electrodes disposed on the pair of main surfaces and grooves provided on one of the main surfaces of the piezoelectric substrate. The grooves divide at least one of the electrodes into a plurality of divided electrodes. One of the plurality of divided electrodes defines an input/output electrode. A maximum distance between the outer edges of two of the grooves disposed opposite to each other across the input/output electrode is about 0.5 to about 0.55 times the length of one side edge of the piezoelectric substrate.

Abstract: A piezoelectric element vibrating in a longitudinal vibration mode includes external electrodes which are provided on front and back major surfaces of a piezoelectric substrate. Conductive sections are fixed onto nodal portions of the piezoelectric element on one of the major surfaces of the piezoelectric substrate. The piezoelectric element is constructed such that a relationship T1/T is set at about 0.5 or less and a relationship L1/L is set at about 0.2 or less, where a thickness and a length of the piezoelectric element are T and L, respectively, and a thickness and a length of the support sections are T1 and L1, respectively.

Abstract: A piezoelectric resonator vibrates in a square vibration mode and includes a piezoelectric substrate having a first major surface and a second major surface, electrodes provided on the first major surface and the second major surface of the piezoelectric substrate and a groove provided in at least one of the first major surface and the second major surface of the piezoelectric substrate. The groove divides at least one of the electrodes into a plurality of areas such that the electrostatic capacitance of the resonator is changed by varying the position, the width and the depth of the groove provided on the piezoelectric substrate.

Abstract: An ultrasonic transducer comprising, a piezoelectric block which is formed into a plurality of piezoelectric segments by way of one or more slots, spaced apart, on one main surface of the block, the segments being connected with each other at one and the other of the opposed main surfaces of the block, an organic filler filled at least partially in the slots, a first and a second electrodes formed respectively on the one and the other of the continuous main surfaces of the segments, an acoustic matching layer formed on the one main surface of the piezoelectric block, and a backing material formed on the other main surface of the piezoelectric block.

Abstract: A piezoelectric resonator includes a substantially rectangular shaped piezoelectric substrate having a pair of major surfaces and polarized in the thickness direction thereof and a pair of electrodes respectively disposed on the pair of major surfaces of the piezoelectric substrate. One of the electrodes is multiply divided along a dividing line which extends along the longitudinal direction of the piezoelectric substrate. The piezoelectric substrate is polarized such that two portions of the piezoelectric substrate sandwiching the dividing line are polarized in opposite directions.

Abstract: An actuator, comprising a plurality of stacks of unit blocks of an active material of the piezoelectric, electrostrictive, or magnetostrictive type, which blocks are distributed so as to form a tubular structure, together with means enabling an electric or magnetic field to be applied to said unit blocks to cause said unit blocks to deform in such a manner that the tubular structure twists.

Abstract: A wafer with a reversed domain is prepared for two piezoelectric single crystal plates and of about the same thickness by using direct bonding without any adhesive. Driving electrodes are formed on two principal planes of the wafer with a reversed domain to provide a piezoelectric resonator. A piezoelectric resonator having the structure with a reversed polarization and using odd-order vibration modes vibrating with a fundamental wave has a wavelength of a thickness thereof and suppresses scattering of the thickness of the domains with a reversed polarization. In the direct bonding, the axes of the spontaneous polarization of the two piezoelectric single crystal plates are reverse to each other and crystalline axes other than the axes of polarization are shifted intentionally by an angle other than zero. Thus, spurious modes are suppressed in a simple way.

Abstract: A thickness extensional vibration piezoelectric resonator includes a strip-type, substantially rectangular plate-shaped piezoelectric body, first and second excitation electrodes disposed on both sides of the piezoelectric body, the back side and the front sides thereof being opposed to each other with the piezoelectric body disposed therebetween, and an internal electrode disposed in the piezoelectric body. The resonator portion where the first and second excitation electrodes and the internal electrode are opposed to each other define a resonance portion. In the longitudinal direction (a first direction) of the piezoelectric body, vibration-attenuating portions are provided on both sides of the resonance portion. The ratio L/D is within the range of about 9.0 to about 14.0, in which L is the length in the longitudinal direction of the piezoelectric body, T is the thickness, and wherein D=T/N.

Abstract: A piezoelectric component prevents development of a short circuit between separate electrodes of a piezoelectric element and provides a high level of connection reliability. The piezoelectric component includes a piezoelectric element utilizing a longitudinal oscillation mode and being mounted on a mounting substrate. The piezoelectric element has on one main surface thereof a first electrode and a second electrode formed by dividing electrode material via longitudinally extending linear grooves and, on the other main surface, a third electrode. Conductive support members are secured to node sections of the first and second electrodes so as to be spaced apart from each other with respect to the longitudinal dimension of the piezoelectric substrate. The support members are adhered to and secured to pattern electrodes of the mounting substrate by conductive adhesive.

Abstract: A composite structure (3) includes a piezoelectric element (1) sandwiched between fiber composite panels (2). The composite structure can be used as an actuator element. In a method for producing the composite structure, the fiber composite panels are pre-stressed and pre-strained by applying respective pre-stressing forces (F.sub.1, F.sub.2) in opposite directions along two substantially perpendicular axes in the plane of the panel. The pre-stressed and pre-strained condition of the fiber composite panels (2) is maintained, while the panels are adhesively bonded (5) surfacially onto the piezoelectric element (1). After the bonding is completed, the pre-stressing forces are removed from the fiber composite panels. As a result, in the finished composite structure (3), the fiber composite panels (2) are under internal tension, while the piezoelectric element (1) is under internal compression. The pre-stressing forces (F.sub.1, F.sub.

Abstract: A pressure and temperature transducer includes an elongate housing formed from double rotation cut crystal quartz, an elongate plate-like resonator formed from double rotation cut crystal quartz capable of vibrating under an applied electric field located within the housing, the resonator being formed in unitary construction with the housing. The long edges of the resonator are connected to the interior walls of the housing, and short edges of the resonator are free and extend across the interior of the housing in a substantially continuous curve. Electrodes are located on opposite faces of the resonator for applying an electric field which causes the resonator to vibrate. End caps, formed from double rotation cut crystal quartz, are provided at each end of the housing. A borehole tool includes a tool body which can be positioned in a borehole, a probe for sampling fluid in the borehole; and a pressure and/or temperature transducer, connected to the probe for making measurements on the fluid.

Abstract: An energy trap type piezoelectric resonator includes a plate-like piezoelectric resonator element constructed to vibrate in a third harmonic of a longitudinal vibration mode in a thickness direction thereof and such that both main surfaces of the resonator element are laminated with sealing substrates. Sealed spaces are provided so as to allow a vibrating portion of oppositely disposed vibrating electrodes to vibrate. Sealing portions, in which the piezoelectric resonator element and the sealing substrates are joined and connected around the sealed spaces, are constructed so that when the thickness of a piezoelectric substrate is represented by t and the shortest distance to the sealing portion from the vibrating electrodes is d, the sealed spaces satisfy the relationship 0<d/t<5.

Abstract: A ladder-type piezoelectric filter includes series resonators including substantially rectangular piezoelectric resonators adapted to vibrate in a longitudinal vibration mode, and parallel resonators including substantially square piezoelectric resonators adapted to vibrate in a square vibration mode. The series resonators and the parallel resonators are connected to each other via terminals so as to define a ladder circuit. A pair of grooves are respectively provided on one of the major surfaces of each series resonator at symmetrical positions with respect to the center-line which is substantially perpendicular to the longitudinal direction of the series resonator such that the pair of grooves extend in a direction that is substantially parallel to the center-line of the series resonator and divide the electrode on the one major surface to thereby adjust an electric capacitance between the pair of electrodes respectively disposed on the pair of major surfaces of the series resonator.

Abstract: A piezo-electric resonator includes terminal plates holding a piezo-electric substrate and which are stored in a case. The piezo-electric substrate can be formed from piezo-electric ceramics. The piezo-electric ceramic plate has projections at the non-vibrating sections of its cuter circumferential side surfaces. When the centers of the piezo-electric ceramic plate are held by the terminal plates, the projections do not contact the inner surfaces of the case. When the position of the piezo-electric ceramic plate is displaced due to external vibration, the projections may contact the inner surfaces of the case and the vibrating sections of the piezo-electric ceramic plate do not contact the inner surfaces of the case. Due to this fact, its electrical characteristics are not changed. in addition, since this configuration is set such that the piezo-electric ceramic plate can be slightly moved in the case, the piezo-electric ceramic plate is less likely to receive a high shock or stress through the case.

Abstract: An energy-trap thickness extensional vibration mode piezoelectric resonator utilizes a harmonic of a thickness extensional vibration mode achieves excellent resonant characteristics that are hardly affected by portions of the resonator which are physically supported. The energy-trap thickness extensional vibration mode piezoelectric resonator includes a piezoelectric strip, first and second excitation electrodes located on opposite surfaces of the piezoelectric strip, and an internal electrode disposed inside the piezoelectric strip. The first and second excitation electrodes are located on opposite ends of the piezoelectric strip in an overlapping arrangement. The internal electrode is located opposite to the first and second excitation electrodes. The resonator is designed so that a ratio L/d is not less than about 14, where L is the dimension of the piezoelectric strip 2 in the longitudinal direction, t is the thickness, and d=t/n.

Abstract: A piezoelectric component prevents development of a short circuit between separate electrodes of a piezoelectric element and provides a high level of connection reliability. The piezoelectric component includes a piezoelectric element utilizing a longitudinal oscillation mode and being mounted on a mounting substrate. The piezoelectric element has on one main surface thereof a first electrode and a second electrode formed by dividing electrode material via longitudinally extending linear grooves and, on the other main surface, a third electrode. Conductive support members are secured to node sections of the first and second electrodes so as to be spaced apart from each other with respect to the longitudinal dimension of the piezoelectric substrate. The support members are adhered to and secured to pattern electrodes of the mounting substrate by conductive adhesive.

Abstract: An energy trapping piezoelectric device trapping a thickness vibration into projections which suppress a reflection of a vibration from end portions of electrodes provided substantially on a piezoelectric plate, and which suppress unnecessary spurious vibrations, low impedance and higher frequency, and a method of easily producing such a piezoelectric device are provided. The piezoelectric device has an energy trapping projection provided over a piezoelectric plate, and a top electrode is divided into a exciting electrode and dummy electrode. A small gap is provided between the divided electrodes, and the electrodes are electrically insulated from each other. The thickness vibration is not generally reflected, and vibrating energies due to the thickness vibrations are substantially trapped into the projections provided on the piezoelectric plate.

Abstract: A piezoelectric resonator having a small spurious resonance, a large frequency difference .DELTA.F between the resonant frequency and the anti-resonant frequency, adjustable capacitance, and high design flexibility includes a base member formed by laminating, for example, a plurality of piezoelectric layers and internal electrodes. When the length, width, and thickness of the base member are indicated by L, W and T, respectively, the dimensions of the member are selected to satisfy the conditions of L.gtoreq.2W and L.gtoreq.2T. The base member is polarized at both ends of each internal electrode in opposite directions. A groove is preferably formed on one lateral surface of the base member, and at both sides of the groove, the internal electrodes are alternately covered with two insulating films. The two insulating films are respectively formed to cover the different internal electrodes. External electrodes are formed on both sides of the groove of the base member and are connected to the internal electrodes.

Abstract: An energy-trapping thickness-shear resonator includes a piezoelectric substrate, a first electrode extending from a first end to a central portion of a first surface of the piezoelectric substrate and a second electrode extending from a second end to the central portion of a second surface of the substrate. Thus, the resonator utilizes thickness shear vibrations generated in a portion of the piezoelectric substrate located between the first and second electrodes at the central portion of the substrate. The width W of the la substrate is set to be equal to or less than about 0.7 mm and also to satisfy both of the following expressions (1) and (3) or to satisfy both of the expressions (2) and (3):(1) 0<W<k T/(1-a)(2) k(2n-1)T/(1-a)<W<k(2n+1)T/(1-a)(3) 0 21 .alpha.<(fa-fr)/fawhere T indicates the thickness of the piezoelectric substrate; k is 1/2; f.sub.OSC equals fa (1-.alpha.); f.sub.

Abstract: A ladder type piezoelectric filter has a circuit configuration such that a group delay time characteristic of the filter can easily be improved. The piezoelectric filter includes six resonators, a pair of series resonators S1 and S2 connected in series between input and output terminals. A pair of parallel resonators P1 and P2 and another pair of parallel resonators P3 and P4 are respectively connected between the connection point of the series resonators S1 and S2 and a grounding terminal and between the connection point of the downstream series resonator S2 and the output terminal and the grounding terminal.

Abstract: A wafer with a reversed domain is prepared for two piezoelectric single crystal plates 11 and 12 having about the same thickness as each other by using direct bonding without any adhesive. Then, driving electrodes 13 are formed on two principal planes of the wafer with a reversed domain to provide a piezoelectric resonator. A piezoelectric resonator having the structure with a reverses polarization and using odd-order vibration modes vibrating with a fundamental wave has a wavelength of a thickness thereof suppresses scattering of the thickness of the domains with a reversed polarization. In the direct bonding, the axes of the spontaneous polarization of the two piezoelectric single crystal plates are reverse to each other and crystalline axes other than the axes of polarization are shifted intentionally by an angle other than zero. Thus, spurious modes are suppressed in a simple way.

Abstract: A piezoelectric transformer includes a piezoelectric plate in which a pair of cuts are formed in the piezoelectric plate at a position corresponding to a nodal point of the piezoelectric plate. The pair of cuts form a cut-out projection. Connection electrodes electrically connected to input electrodes are respectively formed on input-side cut-out projections. In this piezoelectric transformer, the desired support and electrical connection are made through the cut-out projections.

Abstract: A piezoelectric element prevents the development of a short circuit between separate electrodes and provides a high level of connection reliability. The piezoelectric element utilizing a longitudinal oscillation mode includes a piezoelectric substrate which has on one main surface thereof a first electrode and a second electrode separated by longitudinally extending linear grooves and, on the other main surface, a third electrode. Conductive support members are secured to node sections of the first and second electrodes so as to be spaced apart from each other with respect to the longitudinal dimension of the piezoelectric substrate.

Abstract: A piezoelectric resonator having a miniature size and being fabricated at a low cost is used in a ladder-type filter that has a substrate, on the front and back surfaces of which line electrodes are provided. A series resonator includes a substantially rectangular piezoelectric plate vibrating in a length vibration mode and has vibrating electrodes located on a pair of opposite side edge surfaces of the substantially rectangular piezoelectric substrate. A parallel resonator including a substantially rectangular piezoelectric plate vibrating in a length vibration mode has vibrating electrodes located on the front and back major surfaces of the substantially rectangular piezoelectric substrate. The series and parallel resonator are mounted on the substrate in such a manner as to be spaced apart from each other. The vibrating electrodes of the series resonator are connected with the line electrodes, respectively, by using a conductive adhesive agent.

Abstract: An improved composite ultrasonic transducer, and elements therefor, which may be made autoclavable, and a method of making these elements. A number of planar precursors comprising strips of piezoelectric ceramic material separated from one another by a polymer material are stacked one above another with the ceramic strips aligned with one another, and with electrical conductors disposed between each of the planar precursors. These precursors are then bonded to one another, to form a bonded assembly. The bonded assembly is then slit along parallel lines perpendicular to the direction of elongation of the ceramic strips, subdividing the strips into individual ceramic members and also subdividing the planar conductors, forming ribbon-like conductors extending between opposite sides of the array. The saw kerfs are filled with a hardening polymer material. The ribbon-like conductors reaching the edges of the assembly are then connected electrically in parallel, reducing the capacitance of the individual emitters.