Abstract: A film bulk acoustic wave resonator including a piezoelectric body 1, and a first electrode 2 and a second electrode 3 that are provided respectively on the main surfaces of the piezoelectric body, the piezoelectric body being applied an electric field through the first and the second electrodes so as to generate a resonant vibration. A first mass load material portion 4 having an annular shape is provided outside the planar region of the first electrode on the main surface of the piezoelectric body, a mass load effect thereof being larger than that of the first electrode. The outer periphery of the first electrode and the inner periphery of the first mass load material portion are spaced apart from each other, whereby the first electrode and the first mass load material portion are electrically insulated from each other. The first mass load material portion has a laminated structure including a first auxiliary electrode layer 2a and a load material layer 4a formed on the auxiliary electrode layer.

Abstract: A piezoelectric filter comprises a substrate and a plurality of piezoelectric resonators provided on the same substrate. Each piezoelectric resonator comprises a cavity formed in the substrate, a lower electrode formed on the substrate, covering the cavity, a piezoelectric material layer formed on the lower electrode, and an upper electrode formed on the piezoelectric material layer. At least one of the piezoelectric resonators has a cavity formed of a plurality of cells.

Abstract: A piezoelectric resonator filter for allowing a high-frequency signal in a desired frequency band to pass therethrough. The piezoelectric resonator filter presents a low insertion loss while securing satisfactory characteristics in a stop band. The piezoelectric resonator includes two or more reactance elements in serial connection between input and output terminals, at least three or more piezoelectric resonators in parallel connection between the input and output terminals, and an inductor having a grounded end. The reactive elements and resonators of the piezoelectric resonator are arranged in a ladder connection. Among the three or more piezoelectric resonators, only those piezoelectric resonators which do not adjoin each other are connected in common to the inductor.

Abstract: An electronic device according to the present invention includes a functional element acting as a predetermined circuit packaged using a resin member. The electronic device comprises a wiring substrate having a wiring member for electric connection with an external circuit; the functional element mounted on one main surface of the wiring substrate so as to be electrically connected to the wiring member; and the resin member provided on the one main surface of the wiring substrate having the functional element, so as to package the functional element. The resin member includes a filler formed of a magnetic material.

Abstract: A piezoelectric resonator of the present invention is structured such that on a substrate 5 having a cavity 4 formed therein, a lower electrode 3, a piezoelectric body 1, a spurious component control layer 16, and an upper electrode 2 are formed in this order from bottom up. The spurious component control layer 16 is a layer for controlling a spurious frequency, and composed of, for example, a metallic material, a dielectric material, or a piezo electric material. By additionally providing the spurious component control layer 16, it is made possible to cause variation of the spurious frequency due to unwanted variation to become greater than variation in resonance frequency of the main resonance of the piezoelectric resonator. Thus, it is possible to realize a piezoelectric resonator having an admittance frequency response where no spurious component occurs between resonance frequency fr and antiresonance frequency fa.

Abstract: A piezoelectric device of the present invention includes first and second piezoelectric resonators. The first piezoelectric resonator has a structure in which a cavity, a lower electrode, a piezoelectric layer, and an upper electrode are formed on a substrate. The second piezoelectric resonator has a structure in which a cavity, a lower electrode, a piezoelectric layer, and an upper electrode are formed on the substrate. A feature of the above-structure piezoelectric device is that the piezoelectric layers, have the same film thickness, and the depth of the cavity of the first piezoelectric resonator is different from the depth of the cavity of the second piezoelectric resonator.

Abstract: An acoustic resonator device includes a substrate, a first acoustic resonator and a second acoustic resonator. The first acoustic resonator is formed on the substrate, and has a first upper electrode, a first piezoelectric layer, and a first lower electrode layer, and resonates in a ?/4 mode at a first resonant frequency. The second acoustic resonator is formed on the substrate, and has a second upper electrode layer, a second piezoelectric layer, and a second lower electrode layer, and resonates in a ?/2 mode at a second resonant frequency different from the first frequency. In the acoustic resonator device, materials and thicknesses of the first lower electrode layer and the second lower electrode layer are common and substantially equal, and materials and thicknesses of the first piezoelectric layer and the second piezoelectric layer are common and substantially equal.

Abstract: A piezoelectric resonator includes a substrate, a lower electrode provided on or above the substrate, a piezoelectric member provided on or above the lower electrode, an upper electrode provided on or above the piezoelectric member, and a cavity provided below a vibration member including the lower electrode, the piezoelectric member, and the upper electrode. In a case where a resonance frequency of vibration with a thickness of the vibration member being a half of a wavelength is taken as fr1, an average of ultrasonic velocity in a material forming the cavity is taken as Vc2, and a value determined based on the resonance frequency fr1 and the average of ultrasonic velocity Vc2 is ?c (=Vc2/fr1), a depth t2 of the cavity is set as, ( 2 ? n - 1 ) × ? ? ? c 4 - ?c 8 ? t2 ? ( 2 ? n - 1 ) × ? ? ? c 4 + ? ? ? c 8 , where n is an arbitrary natural number.

Abstract: A thin film bulk acoustic resonator includes a piezoelectric film, and a pair of electrodes between which the piezoelectric film is interposed. The piezoelectric film includes an outer region extending outwards from at least a portion of the periphery of a resonator portion composed of the pair of electrodes and the piezoelectric film. The outer region includes, in at least a portion thereof, an acoustic damping region for damping acoustic waves.

Abstract: A piezoelectric element of the present invention includes a substrate, a lower electrode layer, a piezoelectric layer, an upper electrode layer, a cavity portion formed below a piezoelectric vibrating portion, and at least two bridging portions. The at least two bridging portions are formed so as not to be line-symmetric with respect to any line segment traversing the piezoelectric vibrating portion and/or so as not to be point-symmetric with respect to any point in the piezoelectric vibrating portion in a projection of the piezoelectric vibrating portion in the laminating direction.

Abstract: A series piezoelectric resonator 11 is connected in series between an input terminal 15a and an output terminal 15b. A first electrode of a parallel piezoelectric resonator 12a is connected to a connection point between the input terminal 15a and the series piezoelectric resonator 11, and a second electrode of the parallel piezoelectric resonator 12a is connected to a first terminal of an inductor 13a. A first electrode of a parallel piezoelectric resonator 12b is connected to a connection point between the series piezoelectric resonator 11 and the output terminal 15b, and a second electrode of the parallel piezoelectric resonator 12b is connected to a first terminal of an inductor 13b. Second terminals of the inductors 13a and 13b are grounded. An additional piezoelectric resonator 14 is connected between the second electrode of the parallel piezoelectric resonator 12a and the second electrode of the parallel piezoelectric resonator 12b.

Abstract: A complex RF device is provided which is composed of two RF circuits stacked vertically. The complex RF device comprises a substrate, a second RF circuit provided on the substrate, and a first RF circuit which is provided on the second RF circuit and does not require a substrate. The first RF circuit is formed on another substrate before being transferred onto the second RF circuit.

Abstract: An upper electrode 103 is provided on one main surface of a piezoelectric layer 101, and a lower electrode 102 is provided on the other main surface thereof. A vibration section 104 is an area in which the lower electrode 102, the piezoelectric layer 101 and the upper electrode 103 overlap in a vertical projection direction. Line electrodes 108 for respectively connecting the lower electrode 102 and the upper electrode 103 to input/output electrodes 107 are provided on the one main surface and the other main surface of the piezoelectric layer 101. The vibration section 104 is placed on (connected to) the substrate 105 via the support section 109. The support section 109 is provided on an area of the piezoelectric layer 101 excluding the area on which the vibration section 104 is provided and the area on which the input/output electrodes 107 and the line electrodes 108 are provided.

Abstract: An acoustic resonator according to the present invention includes a substrate 105, a support section 104 provided on the substrate 105, a lower electrode 103 provided on the support section 104, a piezoelectric body 101 provided on the lower electrode 103, and an upper electrode 102 provided on the piezoelectric body 101. The lower electrode 103, the piezoelectric body 101 and the upper electrode 102 form a vibration section 107. The support section 104 for supporting the vibration section 107 is shaped such that at least one portion of a vertical cross-section thereof has a curvature.

Abstract: A piezoelectric transformer includes a piezoelectric ceramic disc having one face and the other face opposite to each other in a thickness direction. A pair of low-impedance portions acting as one of a driving portion and a generator portion are disposed in the piezoelectric ceramic disc symmetrically with respect to a central axis of the piezoelectric ceramic disc, while a pair of high-impedance portions acting as the other of the driving portion and the generator portion are disposed in the piezoelectric ceramic disc symmetrically with respect to the central axis so as to be electrically separated from the low-impedance portions such that the piezoelectric transformer is driven in a radial extensional vibration mode of the piezoelectric ceramic disc.

Abstract: A piezoelectric resonator comprises a piezoelectric material layer 101, a first electrode 102 formed on one major surface of the piezoelectric material layer 101, and having a cross-section in the shape of a trapezoid whose longer side contacts the piezoelectric material layer 101, and a second electrode 103 formed on the other major surface of the piezoelectric material layer 101, and having a cross-section in the shape of a trapezoid whose longer side contacts the piezoelectric material layer 101.

Abstract: A piezoeletric resonator includes: a substrate; a lower electrode formed on or above the substrate; a piezoeletric body formed on or above the lower electrode; an upper electrode formed on or above the piezoeletric body; and a cavity under a vibrating portion formed by the lower electrode, the piezoeletric body, and the upper electrode. Where a resonant frequency of vibration with a thickness of the vibrating portion being a half of a wavelength is taken as fr, an average of ultrasonic velocity in a material forming the cavity is taken as Vc, and a value determined based on the resonant frequency fr and the average of ultrasonic velocity Vc is taken as ?c (=Vc/fr), a depth of the cavity is set so as to be equal to or larger than n×?c/2??c/8 and equal to or smaller than n×?c/2+?c/8.

Abstract: In a balanced/unbalanced type coupled FBAR filter 100, an area size of a first lower electrode 102 is generally equal to a total area size of second and third lower electrodes 104 and 106 and an area for isolating the second and third lower electrodes 104 and 106. An area size of a first upper electrode 103 is generally equal to a total area size of second and third upper electrodes 105 and 107 and an area for isolating the second and third upper electrodes 105 and 107. The third lower electrode 106 and the second upper electrode 105 are located to face each other, and the third upper electrode 107 and the second lower electrode 104 are located to face each other. Apart of the second lower electrode 104 and a part of the second upper electrode 105 are located to face each other.

Abstract: A coupled FBAR filter 100 includes first and second input/output vibration portions110 and 111 respectively including first and second lower electrodes 104 and 106, first and second upper electrodes 105 and 107, and a piezoelectric thin film 103 interposed therebetween; and a cavity 102 for commonly guaranteeing vibrations of the first and second input/output vibration portions 110 and 111 so as to couple the vibrations. The first and second input/output vibration portions 110 and 111 are located adjacently in contact with each other with a step therebetween, such that the first and second lower electrodes 104 and 106 are not electrically connected to each other and such that the first and second upper electrodes 105 and 107 are not electrically connected to each other. Insulators 108 and 109 are provided in the vicinity of the step.

Abstract: A driving circuit for a piezoelectric transformer is provided, which ensures lighting of all the cold-cathode tubes connected to the piezoelectric transformer, and reduces the difference in brightness between the cathode tubes during steady lighting, thereby enhancing reliability and performance. A plurality of cold-cathode tubes connected to a secondary side of the piezoelectric transformer, and a cold-cathode tube output detector circuit connected in series to a plurality of cold-cathode tubes, for detecting an output state of the respective cold-cathode tubes are provided, and the driving of the piezoelectric transformer is controlled based on a detection signal from the cold-cathode tube output detector circuit. Because of this, the piezoelectric transformer performs the same operation as that with respect to one cold-cathode tube.