ULTRASONIC WAVE CONVERTER

PURPOSE:To simplify the structure, to make the size small and to reduce the weight of the converter light by forming a vibrator only with a piezoelectric thin film and an electrode without use of a beam made of silicon or silicon oxide. CONSTITUTION:A vibrator 1 consists of a piezoelectric thin film 3 comprising 2-layer structure of a low resistance layer 2a whose electric resistance is small and a high resistance layer 2b whose electric resistance is large, on which 1st and 2nd electrode layers 4, 5 are formed, and the one end of the film 3 is supported to a substrate 6 as a cunti-lever. When an AC voltage is applied between upper and lower electrode layers 4, 5 of the piezoelectric thin film 3, since the electric field is concentrated onto only the high resistance layer 2b, expansion/contraction is caused in the high resistance layer, while no expansion/contraction is caused in the low resistance layer 2a, the vibrator 1 having a beam shape as a whole is vibrated vertically and then an ultrasonic wave is sent. Thus, the ultrasonic wave converter of simple structure, high performance and small size and light weight is obtained.