| 摘要 |
PURPOSE:To obtain ultrasonic wave transducers in liquid or air increasing the electroacoustic conversion efficiency with multiplex construction in phase arrangement of a plurality of curved type macromolecular piezoelectric films. CONSTITUTION:Constitution is made that a plurality of curved type conversion elements 1a...1n are located with a certain distance and input and output electrode terminals 6, 6' are provided. When the polarization of the conversion elements is oriented to the same direction, the distances 7a, 7b... of the conversion elements are taken as a half wave length, the polarity of front and back electrodes of each piezoelectric film is alternately inverted and connected parallelly and the ultrasonic waves independently radiated from the conversion elements are satisfied for the phase matching conditions, allowing the superposition of output sound pressure at the sound reception point axially apart sufficiently from the transducers. Accordingly, the increase in the output sound pressure proportional to the number of conversion elements is obtained to the same input voltage. Further, if the direction of polarization of each conversion element is not arranged, electrical connection is made so that the phase matching conditions can be satisfied. |
