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.

Disclosed is an ultrasonic transducer including: at least one piezoelectric wafer having two parallel planar main faces: a front face and a posterior face; at least one posterior plate having two parallel planar main faces: an anterior face and a rear face, the anterior face of the posterior plate extending facing, and in contact with, the posterior face of the piezoelectric wafer. The posterior plate has a thickness between three and seven times the thickness of the piezoelectric wafer. The posterior plate has an acoustic impedance between 10 MPa.Math.s.Math.m−1 and 35 MPa.Math.s.Math.m−1. Also disclosed is a method for assembling such a transducer as well as a flowmeter including at least one such transducer.

A sound generator includes a housing (20), a stand (90) supporting the housing (20), a piezoelectric vibrator (60) including a piezoelectric element (61), and an anchor applying a load to the piezoelectric vibrator (60). While the load from the anchor is being applied to the piezoelectric vibrator (60), the piezoelectric vibrator (60) deforms in response to a sound signal, and deformation of the piezoelectric vibrator (60) vibrates a mounting surface (150) on which the sound generator is mounted, causing sound to be emitted from the mounting surface (150).

An ultrasonic transducer, including a piezoelectric element with physical characteristics of radial resonant frequencies and thickness resonant frequencies, and with an upper surface and a lower surface opposite to each other through the piezoelectric element and a lateral surface connecting the upper surface and the lower surface, and an acoustic matching layer set on the upper surface of the piezoelectric element and having a first resonant matching part and a second resonant matching part, wherein a thickness of the first resonant matching part in a direction perpendicular to the upper surface is greater than a thickness of the second resonant matching part in the direction, and the thickness of the first resonant matching part matches one radial resonant frequency of the piezoelectric element and the thickness of the second resonant matching part matches another radial resonant frequency or one of the thickness resonant frequency of the piezoelectric element.

A Piezoelectric Micromachined Ultrasonic Transducer (PMUT) device is provided. The PMUT includes a substrate and an edge support structure connected to the substrate. A membrane is connected to the edge support structure such that a cavity is defined between the membrane and the substrate, where the membrane is configured to allow movement at ultrasonic frequencies. The membrane includes a piezoelectric layer and first and second electrodes coupled to opposing sides of the piezoelectric layer. The PMUT is also configured to operate in a Surface Acoustic Wave (SAW) mode. Also provided are an integrated MEMS array, a method for operating an array of PMUT/SAW dual-mode devices, and a PMUT/SAW dual-mode device.

A Piezoelectric Micromachined Ultrasonic Transducer (PMUT) device is provided. The PMUT includes a substrate and an edge support structure connected to the substrate. A membrane is connected to the edge support structure such that a cavity is defined between the membrane and the substrate, where the membrane is configured to allow movement at ultrasonic frequencies. The membrane includes a piezoelectric layer and first and second electrodes coupled to opposing sides of the piezoelectric layer. The PMUT is also configured to operate in a Surface Acoustic Wave (SAW) mode. Also provided are an integrated MEMS array, a method for operating an array of PMUT/SAW dual-mode devices, and a PMUT/SAW dual-mode device.

An acoustic logging tool includes a first acoustic transducer and a second acoustic transducer. At least a portion of the first transducer is parallel with the second transducer. The first and second acoustic transducers are configured to propagate an acoustic signal in the same direction. The first acoustic transducer is configured to generate an acoustic output having a different frequency than the second acoustic transducer.

An apparatus may include one or more segmented piezoelectric micromechanical ultrasonic transducer (PMUT) elements. Each segmented PMUT element may include a substrate, an anchor structure disposed on the substrate and a membrane disposed proximate the anchor structure. The membrane may include a piezoelectric layer stack and a mechanical layer. The anchor structure may include boundary portions that divide the segmented PMUT element into segments. Each segment may have a corresponding segment cavity. The boundary portions may correspond to nodal lines of the entire membrane. The membrane may include a membrane segment disposed proximate each segment cavity. The membrane may be configured to undergo one or both of flexural motion and vibration when the segmented PMUT element receives or transmits signals.

The vibration device includes a base, a movable bench, a first horizontal excitation unit, a second horizontal excitation unit, and a vertical excitation unit. The vibration device includes a first middle bench and a second middle bench between the base and the movable bench. The vibration device includes first horizontal elastic support units, second horizontal elastic support units, and vertical elastic support units that elastically connect the base, the first middle bench, the second middle bench, and the movable bench sequentially in the first horizontal direction, the second horizontal direction, and the vertical direction. If overall device is supposed as a first mass body, a second mass body, and a third mass body with the first horizontal elastic support units and the second horizontal elastic support units as boundaries, respective barycentric positions of these mass bodies are almost the same in the vertical direction and horizontal direction.

The piezoelectric vibrator element is miniaturized, and at the same time, the vibration leakage is suppressed. The piezoelectric vibrator element is formed so that the total length L1 of the piezoelectric vibrator element, the length L2 of the base, the width L3 of the connection part, the length L4 of the support arm part fulfill all of the following conditions A through C, Condition A: 0.1≦L2/L1≦0.2, Condition B: 0.4≦L3/L2≦0.6, Condition C: L4/L1≧0.7. While the miniaturization is realized by shortening the base due to the condition A, the distance via the base can be elongated due to the condition B. Further, by increasing the length of the support arm parts due to the condition C, it is possible to increase the total mass of the path transmitting the vibration to absorb the vibration to thereby further suppress the vibration leakage.