Showing papers on "Piezoelectric motor published in 1972"

Piezoelectric transducer and noise making device utilizing same

Abstract: A noise making device, using a piezoelectric transducer, includes a piezoelectric element mechanically coupled to a substrate and an electrical circuit for energizing the transducer. The piezoelectric element includes a piezoelectric crystal, first and second electrode means carried by the crystal, and means dividing one of the electrode means into electrically isolated areas so as to provide a third electrode means.

Linear transducer array for ultrasonic image conversion

Abstract: An ultrasonic transducer comprising a linear array of piezoelectric elements for converting a single line from a compressional acoustic image field to electrical impulses which, in turn, provide a means for converting the incident compressional image field to a visual representation. In order to match the configuration of the acoustic image field, the array of piezoelectric elements, in a preferred embodiment, has the configuration of an arc, that is, the array is arranged in a straight line in one plane and in an arc in a plane orthogonal to the first. The transducer is made up of a plurality of assemblies each of which is composed of segments of piezoelectric material each held in a supporting slot in a length of metal plate which slot is filled with a material selected to provide impedance matching between the piezoelectric material and the transmission medium. The array of piezoelectric elements is made from the piezoelectric segments by making fine cuts therein perpendicular to the supporting slot to form a plurality of piezoelectric "islands" and each island is electrically connected to utilization circuitry. In a preferred embodiment, an ultrasonic cylindrical lens is affixed to the supporting structure along the supporting slot and intermediate the piezoelectric array and the compressional acoustic image field to broaden the angular sensitivity pattern in the direction to compensate for the disparity between length and width (greater length) of piezoelectric elements or islands.

Piezoelectric oscillator system

Abstract: A piezoelectric oscillator system includes a coupling oscillator having a piezoelectric transducer and a plate for vibration in a bending mode. The coupling oscillator is mechanically connected to a second plate which is also caused to vibrate in a bending mode upon energization of the piezoelectric transducer by an AC voltage. The second-mentioned plate may carry a second piezoelectric transducer for generating an electrical output signal. The system includes means for effecting self generation of the AC voltage through the provision of a tap electrode associated with the piezoelectric transducer for taking off a feedback control signal for a transistor switching circuit which may be constructed to provide an AC rectangular waveform.

Depolarization protection for ceramic piezoelectric motor

Abstract: A piezoelectric motor employs a bending strip or several bending strips having piezoelectric ceramic elements which are mechanically connected in parallel in a single or several packages wherein each bending strip undergoes bending or torsional deformation upon the application of an alternating electrical voltage applied to one or several electrode pairs carried by the ceramic bending strip. The direction of the voltage reverses from between the same direction and the direction opposite to that of the permanent polarization of the ceramic material between the pair of electrodes and the motor includes a circuit comprising parallel connected rectifier and resistor elements connected in series with pairs of electrodes and having the rectifier poled with its forward direction opposite to that of the permanent polarization of the ceramic material and the resistor is dimensioned such that the peak voltage across a pair of electrodes does not exceed a predetermined fraction of the peak value of the applied alternating voltage during the non-conducting phase of the rectifier.

An ultrasonic convolver having piezoelectric and semiconductor properties

Abstract: A device for performing the function of convolution comprises either a properly oriented piezoelectric semiconductor or a properly oriented piezoelectric insulator with an adjacent semiconductor and means for launching ultrasonic waves into or on the piezoelectric crystal. When one launches ultrasonic waves from the opposite ends of a piezoelectric crystal so that the two waves travel toward each other, when the two waves meet, a rf signal of large amplitude, at the sum frequency of the ultrasonic waves, will be detected by the semiconductor and the envelope (time function) of the sum-frequency rf signal represents the convolution integral between the two envelopes of the ultrasonic waves which were launched into the crystal is d-c biased to enhance the signal and in other configurations the semiconductor is not d-c biased.

Piezoelectric gas lighter

Abstract: A piezoelectric gas lighter having a casing; a fuel reservoir disposed within said casing; a burner valve associated with the fuel reservoir for permitting the egress of fuel therefrom; a piezoelectric generator housed in the casing and having a piezoelectric element for generating a high voltage in response to a compressive force and force means arranged in alignment with the piezoelectric element to exert the compressive force thereon; a block member disposed on the fuel reservoir; a thumb piece pivotally supported on the block member and rotatable in perpendicular relation to the movement of the force means of the piezoelectric generator; and a cam lever operatively associated with the thumb piece to transmit the movement of the thumb piece to the force means of the piezoelectric generator; and spark means connected to the piezoelectric element for igniting the fuel emitted by the burner valve in response to the high voltage whereby the rotation of the thumb piece causes the piezoelectric element to be applied with the compressive force in a direction perpendicular to the rotation through the cam lever to generate a high voltage in the piezoelectric element which actuates the spark means to ignite the fuel.

On mechanical response of a non-uniform piezoelectric transducer under the influence of a body-force

Abstract: The mechanical response of a non-uniform piezoelectric transducer when there is a body force acting on it has been evaluated using the methods of transform calculus.