Piezoelectric sensor

About: Piezoelectric sensor is a research topic. Over the lifetime, 7127 publications have been published within this topic receiving 115903 citations.

Piezoelectric element drive circuit

Abstract: Disclosed is a piezoelectric element drive circuit which comprises a charge circuit for charging the piezolectric element in response to an external signal, and a switching circuit connected between the terminals of the piezoelectric element via reactor means to allow a current flow in one direction selected in response to an external signal for transferring the charges supplied from the charge circuit and stored in the piezoelectric element from its high-potential side to its low-potential side whereby the piezoelectric element is charged to be in the opposite polarity. Optionally, the power stored in the piezoelectric element is regenerated at the power source instead of charging the piezoelectric element in the opposite polarity. With the above drive circuit, the power once supplied to the piezoelectric element from the power source is cyclically used for improved power efficiency.

A lateral-field-excited LiTaO 3 high-frequency bulk acoustic wave sensor

Abstract: The most popular bulk acoustic wave (BAW) sensor is the quartz crystal microbalance (QCM), which has electrodes on both the top and bottom surfaces of an AT-cut quartz wafer. In the QCM, the exciting electric field is primarily perpendicular to the crystal surface, resulting in a thickness field excitation (TFE) of a resonant temperature compensated transverse shear mode (TSM). The TSM, however, can also be excited by lateral field excitation (LFE) in which electrodes are placed on one side of the wafer leaving a bare sensing surface exposed directly to a liquid or a chemi/bio selective layer allowing the detection of both mechanical and electrical property changes caused by a target analyte. The use of LFE sensors has motivated an investigation to identify other piezoelectric crystal orientations that can support temperature-compensated TSMs and operate efficiently at high frequencies resulting in increased sensitivity. In this work, theoretical search and experimental measurements are performed to identify the existence of high-frequency temperature-compensated TSMs in LiTaO3. Prototype LFE LiTaO3 sensors were fabricated and found to operate at frequencies in excess of 1 GHz and sensitively detect viscosity, conductivity, and dielectric constant changes in liquids.

Feasibility study of a self-powered piezoelectric sensor

Abstract: Sensors play a crucial role in structural systems with the concern of reliability/failure issues. The development of wireless monitoring systems has been of great interest because wireless transmission has been proven as a convenient means to transmit signals while minimizing the use of many long wires. However, the wireless transmission systems need sufficient power to function properly. Conventionally, batteries are used as the power sources of the remote sensing systems. However, due to their limited lifetime, replacement of batteries has to be carried out periodically, which is inconvenient. In recent years, piezoelectric materials have been developed as sensing and actuating devices mostly, and power generators in some cases. In this paper, a self-powered piezoelectric sensor is studied, in which one piece of piezoelectric material will be simultaneously used as a sensor and a power generator under vibration environment. Concurrent design with piezoelectric materials in sensor and power generator is integrated with energy storage device. We evaluate sensing and power generating abilities individually, and then their concurrent sensing and energy harvesting performances. The possibilities of the piezoelectric sensor to power wireless transmission systems are discussed. Experimental efforts are carried out to study the feasibility of the self-powered piezoelectric sensor system.

Piezoelectric bimorph microphone built on micromachined parylene diaphragm

Abstract: This paper describes a novel bimorph piezoelectric microphone built on a micromachined parylene diaphragm with two ZnO films of opposite c-axis orientations. Both the sensitivity and signal-to-noise ratio (SNR) of the bimorph parylene-diaphragm microphone have been demonstrated to be much higher than those of a conventional unimorph silicon-nitride-diaphragm microphone.

Apparatus for passive damping of a structure

Abstract: An apparatus for controlling the motion of a structural member on a space platform truss structure, launch vehicle, automobile, building, or the like is comprised of a first driving piezoelectric element and a second constraining piezoelectric element. The first piezoelectric element is embedded in or bonded onto the structural member. The second piezoelectric element is bonded onto the structural member, with a viscoelastic material (VEM) layer sandwiched between the structural member and the second piezoelectric element. The first and second piezoelectric elements are electrically connected in opposite phase. When the structural member is deformed by an applied force, the first driving piezoelectric element is correspondingly deformed, generating an electrical field. The electrical field is then applied in an opposite sense to the second piezoelectric element through the electrical connections, thereby oppositely deforming the second piezoelectric element with respect to the first piezoelectric element. This opposite deformation induces a large shear strain in the VEM layer, giving the apparatus a large damping capacity. Because the system is passive, it has great advantages over prior art systems, because of its greater simplicity, lower cost, easier maintainability, and lower weight.