Electrical generator or motor structure – Non-dynamoelectric – Piezoelectric elements and devices
Patent
1991-12-18
1993-10-19
Stephan, Steven L.
Electrical generator or motor structure
Non-dynamoelectric
Piezoelectric elements and devices
310322, H01L 4108
Patent
active
052549003
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a broad beam ultrasonic transducer.
U.S. Pat. No. 4,677,377 discloses a piezoelectric transducer which is intended to be used as an emitting transducer or as a receiving transducer for ultrasonic waves propagating in air. The use of the transducer disclosed by this publication has solved substantial problems which are associated with the extreme difference between the acoustic wave impedance of the sound-transmitting medium of air and the acoustic wave impedance of a solid body emitting or receiving the ultrasonic waves. This acoustic wave impedance is also referred to as the acoustic characteristic impedance.
The ultrasonic transducer of the aforementioned publication has an acoustic characteristic impedance which in relative terms is substantially closer to the value thereof of air. This is achieved by a sandwich construction which consists of individual mutually spaced piezoelectric laminae disposed in planes parallel to one another, the intermediate spaces, corresponding to the spacings, between these laminae being filled with an inherently stable material which has a low acoustic characteristic impedance value. The material occupying the intermediate spaces forms at least one closed surface of this electroacoustic transducer enclosing the piezoelectric laminae, namely a surface for the emission and/or for the reception of acoustic radiation. In this case, for example, this material occupying the intermediate spaces may extend beyond at least a respective one of the edge surfaces of the individual laminae, so that these edge surfaces of the laminae are covered in relation to the external environment by this material occupying the intermediate spaces.
Such a known transducer may be designed so that this surface of the same which is provided for emission and/or reception has relatively large dimensions as compared with the wavelength, in air, of the emitted or received acoustic radiation. If the individual piezoelectric laminae are excited to execute co-phase oscillation, then, originating from this surface of the transducer, an acoustic wave with a substantially plane phase front is emitted.
The material employed for the laminae is piezoelectric ceramic, e.g. lead zirconate titanate, lead titanate, barium titanate and the like, it being possible for these materials to include dopings and/or substitutions, of, inter alia, manganese, niobium, neodymium etc. to improve their respective properties. The material intended to occupy the intermediate spaces between the laminae is, in this known transducer, for example a thermoplastic material. By way of example, the entire body consisting of this material and the piezoelectric laminae is adhesively bonded together while hot. However, the intermediate spaces in this body may also be filled with a sealing compound consisting of silicon rubber.
With regard to further details with respect to the structural configuration and the production of such a known transducer, reference is made to the aforementioned publication.
SUMMARY OF THE INVENTION
The object of the present invention is to provide an electroacoustic transducer with favorable matching of the acoustic characteristic impedance to the medium of air, which transducer has as its acoustic radiation lobe one which has a relatively small width in the x coordinate direction perpendicular to the direction z of the axis of the acoustic radiation, i.e. a small beam width, and which has a broad beam in the coordinate direction y which is respectively perpendicular to this direction x and to the axial direction z, i.e. possesses a broad beam width in this direction. The structural configuration of the transducer to be provided is intended to be such that, proceeding from a basic type, individual types with beam widths in the y direction which differ from one another in a predeterminable manner can be obtained by the selection of individual dimensions. In particular, it is intended that the broad beam width can be selectable within the range from 50.degree
REFERENCES:
patent: 2814575 (1957-11-01), Lange, Jr.
patent: 2901644 (1959-08-01), Tibbetts et al.
patent: 3674945 (1972-07-01), Hands
patent: 4166967 (1979-09-01), Benes et al.
patent: 4360562 (1982-11-01), Endo et al.
patent: 4523122 (1985-06-01), Tone et al.
patent: 4656384 (1987-04-01), Magori
patent: 4677337 (1987-06-01), Kleinschmidt et al.
patent: 4756808 (1988-07-01), Utsumi et al.
patent: 4771205 (1988-09-01), Mequio
Magori Valentin
Mockl Thomas
LaBalle C.
Siemens Aktiengesellschaft
Stephan Steven L.
LandOfFree
Broad beam ultrasonic transducer does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Broad beam ultrasonic transducer, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Broad beam ultrasonic transducer will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1354432