Patent ID: 6774540
Filing Date: 2004-08-10
Classification: B06B

Abstract:
Sound converting apparatus for performing conversion between electric signals and ultrasonic waves, comprising:a plurality of oscillation bodies for emitting ultrasonic waves converted from said electric signals along a wave propagating direction; and a plurality of electrically conductive bodies each for electrically connecting said oscillation bodies; a plurality of signal lines for inputting electric signals to be applied to respective oscillation bodies; each of said oscillation bodies including a pair of piezoelectric layers respectively having inner surfaces and outer surfaces, extending substantially parallel to said wave propagating direction, said inner surfaces of respective piezoelectric layers opposing to each other; a pair of external electrodes respectively held in contact with said outer surfaces of respective piezoelectric layers and electrically connected with said electrically conductive bodies; and a dividing electrode sandwiched by and held in contact with said inner surfaces of said piezoelectric layers and electrically connected with said signal line, whereby said piezoelectric layers respectively generate electric polarizations, directions of which are opposing to each other and extending substantially parallel to an azimuthal direction perpendicular to said wave propagating direction, and emit ultrasonic waves converted from said electric signals along said wave propagating direction when electrical fields are applied between said external electrodes and said dividing electrode in response to said electric signals, and each of said oscillation bodies has a width with respect to said azimuthal direction and a thickness with respect to said wave propagating direction, and the ratio of said width to said thickness is within a range of from 0.1 to 0.8.