Murata Manufacturing Co., Ltd.

Akihiro Mitani

Hiroaki Kaida

Hironari Yamamoto

Jiro Inoue

Toshio Nishimura

Eitaro Kameda

Toru Kizu

Yasuhiro Shimizu

An ultrasonic wave generation apparatus that includes an ultrasonic wave generation element having an inner space formed by bonding first and second vibrators so as to close off a through-hole or a groove provided in a frame body, and a connecting member that is bonded to the second vibrator supports the ultrasonic wave generation element and is electrically connected to at least one of the first and second vibrators. A ventilation hole that opens into a first side surface of the frame body and that allows the inner space to communicate with the exterior is provided in the frame body. When a direction parallel to the first main surface or the second main surface is a lengthwise direction, an outer side end portion of the ventilation hole in the lengthwise direction and an inner side end portion in the lengthwise direction of the connecting member do not match.

Ultrasonic wave generation apparatus

An ultrasonic generator that is capable of increasing output sound pressure is provided. An ultrasonic generating element is accommodated in an accommodation space that is formed by a first case member and a second case member. The ultrasonic generating element is secured to the first case member via a plurality of first supporting members. The first supporting members are provided so that, in a first acoustic path that includes a space formed between a bottom surface of the ultrasonic generating element and a top surface of the first case member and that extends to sound-wave emission holes, a transverse section of the acoustic path has a portion that becomes smaller than another portion thereof.

Ultrasonic generator

An ultrasonic transducer is provided that includes an ultrasonic wave generator having piezoelectric vibrators, and cases having ultrasonic wave emission holes and accommodating the ultrasonic wave generator. Acoustic paths in which air serves as a medium are formed by the ultrasonic wave generator and the and extend from the piezoelectric vibrators to the ultrasonic wave emission holes. Resonance of air is generated in the acoustic paths by ultrasonic waves generated by the piezoelectric vibrators in which the ultrasonic wave emission holes are open ends of the resonance. The piezoelectric vibrators are driven at a driving frequency at which the temperature-sound pressure characteristic for the resonance of air and the temperature-amplitude characteristic at the driving frequency of the piezoelectric vibrators have opposite tendencies.

Ultrasonic transducer

An ultrasonic generation device including an ultrasonic generation element having a frame, a first piezoelectric vibrator, and a second piezoelectric vibrator and configured to emit ultrasonic waves in a buckling tuning-fork vibration mode in which the first piezoelectric vibrator and the second piezoelectric vibrator vibrate in mutually opposite phases at the same frequency. Further, a housing receives the ultrasonic generation element and has ultrasonic emission ports, a first acoustic path extending from a vicinity of a vibration surface of the first piezoelectric vibrator to a vicinity of the ultrasonic emission ports, and a second acoustic path extending from a vicinity of a vibration surface of the second piezoelectric vibrator to the vicinity of the ultrasonic emission ports.

Ultrasonic generation device

An ultrasonic generator that includes an ultrasonic generating element and a first acoustic path. The ultrasonic generating element includes a frame including a through hole in its central portion, a first transducer being flat-shaped and bonded to a first principal surface of the frame, and a second transducer being flat-shaped and bonded to a second principal surface of the frame and is configured to generate ultrasonic waves in a buckling tuning-fork vibration mode where the first transducer and the second transducer vibrate in mutually opposite phases. The first acoustic path is disposed so as to be adjacent to at least one of both principal surfaces of the ultrasonic generating element and configured to compress the ultrasonic waves generated from the ultrasonic generating element and to allow the ultrasonic waves to propagate therethrough in a direction along the principal surface of the ultrasonic generating element.

To obtain an inexpensive piezoelectric vibration component having vibration characteristics whose degradation resulting from deposition of moisture due to a temperature change is less likely to occur without increasing the cost of a sealing structure and the number of parts, a piezoelectric vibration component includes a piezoelectric vibrating element accommodated in a package being sealed, and when the volume of the piezoelectric vibrating element is Ve and the volume within the package obtained by subtraction of the volume Ve of the piezoelectric vibrator from the volume of the space of the package is Vp&#x3e;()/{()&#xd7;2.72}where Se is the surface area of the piezoelectric vibrating element, Sp is the surface area of the space inside the package when the piezoelectric vibrating element inside the package is absent, and M is the maximum mass of moisture per unit volume [&#x3bc;g/mm] at the use temperature and 100% relative humidity.

Piezoelectric vibration component

A piezoelectric oscillator part capable of suppressing oscillation that leaks from a piezoelectric oscillator to a substrate side is obtained. The piezoelectric oscillator part has a piezoelectric oscillator held on a substrate by first and second conductive holding members. The first conductive holding member is arranged proximal to a first end of the substrate. A terminal electrode connected to the first conductive holding member is arranged proximal to a second end of the substrate opposite the first end. The first conductive holding member and the terminal electrode are electrically connected by a wiring electrode.

Piezoelectric oscillator part

A piezoelectric shear resonator has a substantially rectangular-column piezoelectric element that excites a shear-vibration mode and that has opposing substantially rectangular shear strain surfaces. The shear strain surfaces each have an aspect ratio at which the electromechanical coupling factor reaches substantially a maximum value. When the vertical dimension of the shear strain surfaces is D and the horizontal dimension thereof is Le, the aspect ratio Le/D is expressed by Le/D={&#x3b1;&#xb7;(S/S)+&#x3b2;}&#xb1;0.3, where Sand Sare elastic compliances, &#x3b1;=0.27&#xb7;n+0.45, &#x3b2;=1.09&#xb7;n+0.31, and n is a positive integer.

Piezoelectric shear resonator, composite piezoelectric shear resonator, and piezoelectric resonator component

A longitudinally-coupled multi-mode piezoelectric bulk wave filter using the piezoelectric longitudinal effect includes a plurality of excitation electrodes extending substantially parallel to each other, a laminated piezoelectric body including a plurality of piezoelectric layers arranged between the excitation electrodes and polarized in a predetermined direction, an input electrode and output electrode disposed on a first side surface of the laminated piezoelectric body, and a ground electrode disposed on a second side surface of the laminated piezoelectric body. When an input signal is applied between the input electrode and the ground electrode, vibration modes of different orders of harmonic waves are excited and coupled so that an output signal is output between the output terminal and the ground terminal. Let T represent the dimension of the width between the opposed first and second side surfaces of the laminated piezoelectric body and D represent the distance between the adjacent excitation electrodes, and T/D is equal to or smaller than about 0.9. As a result, a longitudinally-coupled multi-mode piezoelectric bulk wave filter presenting a large out-of-band attenuation is provided.

Longitudinally-coupled multi-mode piezoelectric bulk wave filter and electronic component

A composite vibration device includes a piezoelectric element defining a vibrating member, which is made of a material having a first acoustical impedance, first and second reflecting layers are connected to respective end surfaces of the piezoelectric element, each of the layers are made of a material having a second acoustical impedance lower than the first acoustical impedance, and first and second supporting members. Each of the first and second supporting members is made of a material having an acoustical impedance higher than the second acoustical impedance and is connected to the outer surface of each of the first and second reflecting layers. Vibrations propagated from the piezoelectric element are reflected at the interfaces between the reflecting layers and the supporting members.

Growing community of inventors

Nagaokakyo, Japan

Akihiro Mitani