Broad-band echo sounder

Abstract

An echo sounder includes front and rear masses and a layered product of piezoelectric ceramics sandwiched therebetween, and a hollow space is formed in the front mass for defining a bending vibratory plate portion; a ring-shaped piezoelectric vibrator is accommodated in the hollow space, and has flat major surface or an outer side surface held in contact with the front mass without being fixed to the bending vibratory plate; while the layered product of piezoelectric ceramics gives rise to bending vibrations in the bending vibratory plate, the ring-shaped piezoelectric vibrator is driven for vibrations at the resonant frequency so that an acoustic wave with a large amplitude is radiated from the echo sounder; the bending vibratory plate and ring-shaped piezoelectric vibrator are independently designed so that the echo sounder achieves a high acoustic radiation efficiency without sacrifice of high withstand water pressure.

Dependencies are inferred from the claim text.