An ultrasound probe including: a circuit substrate (23) having a recess in a first region on the lower surface side; a buffer layer (400) composed of an insulating material on a second region different from the first region of circuit substrate (23); and an element array layer (22) including a first piezoelectric element (100) for ultrasound transmission formed in the first region of the circuit substrate (23) without the buffer layer (400), and a second piezoelectric element (200) for ultrasound reception formed in the second region of the circuit substrate (23) on the buffer layer (400). The first piezoelectric element (100) vibrates in a flexural vibration mode on the circuit substrate (23), and the second piezoelectric element (200) vibrates in a thickness vibration mode on the circuit substrate (23).

A capacitive device includes a unit cell including a CMUT, and a transmission/reception plate for impedance matching which is provided above the unit cell via a connection portion, in which a membrane of the CMUT constituting the unit cell is connected to the transmission/reception plate via the connection portion having an area smaller than that of the transmission/reception plate. The area of the transmission/reception plate is desirably larger than the area of a hollow portion of the CMUT.

Pressure vessels that operate at elevated temperatures and pressures (e.g., 600° F./316° C., 20000 psig), and ultrasonic transducers and signal connectors for use therein, are described. The pressure vessels include a housing defining a cavity. The housing includes a cylindrical body with plugs positioned within openings of the cylindrical body. Each plug has a recess extending from an external surface to a location ultrasonically adjacent the cavity. The pressure vessels additionally include transducer assemblies positioned within respective plug recesses. Each transducer assembly includes a signal connector positioned within the recess adjacent the external surface, a transducer having a piezoceramic element positioned within the recess at the location ultrasonically adjacent the cavity, and a metallic interconnection spring interconnecting the transducer to the signal connector.

In described examples of a CMOS IC, an ultrasonic transducer having terminals is formed on a substrate of the IC. CMOS circuitry having ultrasonic signal terminals is formed on the substrate. At least one metal interconnect layer overlies the ultrasonic transducer and the CMOS circuitry. The at least one metal interconnect layer connects the CMOS circuitry ultrasonic signal terminals to the terminals of the ultrasonic transducer.

In the system, two ultrasonic transducers, which form a pair and each have a piezoelectric ceramic plate-shaped element with a rectangular geometry, can be fastened to a surface of a component. The two ultrasonic transducers are arranged at a distance from one another such that there is no direct mechanical contact and they are arranged beside one another with a parallel orientation of their central longitudinal axes. The two elements have a different polarization along their width and are connected with the same polarity to an electrical voltage source. The two plate-shaped elements can also have an identical polarization along their width and can be connected in this case with opposite polarity to an electrical voltage source. At least one ultrasonic transducer and/or at least one further ultrasonic transducer is/are designed to detect ultrasonic waves reflected by defects and/or shear waves simultaneously emitted by the two ultrasonic transducers.

A sensor for ultrasonically measuring a portion of a structure having a temperature significantly above room-temperature, the sensor comprising: a high-temperature portion for intimate contact with the structure, the high-temperature portion comprising at least: at least one transducer for converting a first signal to an ultrasonic transmit signal, and for converting an ultrasonic reflected signal to a second signal; a low-temperature portion comprising at least: at least one digital sensor interface (DSI) to which the transducer is electrically connected, the DSI being configured to transmit the first electrical signal and receive the second electrical signal, and to generate an A-scan signal based on the first and second electrical signals; a wireless interface for transmitting a digital signal based directly or indirectly on at least said A-scan signal; and a battery for powering the DSI and the wireless interface; and an elongated member containing one or more electrical conductors for conducting the first and second signals between the transducer and the DSI, the elongated member being configured to offset the low-temperature portion a sufficient distance away from the high-temperature portion such that the low-temperature portion is subjected to significantly less heat from the structure compared to the high-temperature portion.

An acoustic sensor for sensing environmental attributes within an enclosure is disclosed. The acoustic sensor may include a bulk acoustic wave (BAW) transducer configured to be installed outside the enclosure. The BAW transducer may generate an acoustic wave pulse and receive a reflected acoustic wave pulse. The acoustic sensor may further a waveguide assembly configured to be installed inside the enclosure. The waveguide assembly configured to receive the acoustic wave pulse from the BAW transducer. The acoustic sensor may further include a sensing device, wherein the sensing device may determine a change in one or more acoustic wave propagation parameters, based on the generated acoustic wave pulse and the reflected acoustic wave pulse. The sensing device may further determine one or more environmental attributes within the enclosure, based on the change in the one or more acoustic wave propagation parameters.

Provided is a sensor and method for weld defect detection. The sensor includes several piezoelectric elements which form a matrix arranged on a flexible substrate. Each piezoelectric element is covered with a damping block and surrounded by sound absorbing material, within a flexible protective film. The sensor is simple, highly adaptable and high detection efficiency, which is especially suitable for the quick in-service inspection of long distance welds in large equipment, it has high degree of automation.

The present invention relates to a sensor for continuous detection of minute changes of density in fluids and biological fluids, solids and semisolid bodies by use of a transducer. The invention also relates to a method for continuous detection of changes of density of fluids or solids as well as use of the device.

To provide a vibrator made of a piezoelectric crystal having a larger electromechanical coupling coefficient and a more satisfactory frequency-temperature characteristic than those of quartz, a vibrating piece (101) is made of a Ca.sub.3Ta(Ga.sub.1-xAl.sub.x).sub.3Si.sub.2O.sub.14 single crystal (0<x≤1). In the single crystal, letting θ be a rotation angle from an X-Z plane about an X-axis serving as a rotation axis, 18x+17.5≤θ≤24x+24.5 is set. In addition, the vibrating piece (101) is made of a Ca.sub.3Nb(Ga.sub.1-xAl.sub.x).sub.3Si.sub.2O.sub.14 single crystal (0<x≤1). In the single crystal of this arrangement, letting θ be a rotation angle from an X-Z plane about an X-axis serving as a rotation axis, 25x+23.083≤θ≤32x+26.167 is set.