| 摘要 |
PURPOSE:To make sound pressure on the center axis coincide between each different frequency, by controlling an aperture of plural ultrasonic vibrators. CONSTITUTION:When a spherical end edge whose radius of curvature is (r) divides a vibrator 1 of a circle, etc. by a concentric circle, a round vibrator 1A of a radius a2 which is placed adjacently and has the same focal distance, and a ring-like vibrator 1B whose outside diameter and inside diameter are a1 and a2 of the radius are obtained. When an aperture of the vibrators 1A, 1B is controlled so that center frequencies f1, f2 of transmitting ultrasonic waves of these vibrators 1A, 1B and the radiuses a1, a2 satisfy the condition of the expression, and the product of the frequencies f1, f2 and aperture areas of the vibrators 1A, 1B becomes constant, sound pressure on the center axis can be made to coincide between each different frequency, and a good frequency characteristic can be obtained with respect to attenuation, reflection, etc. of an object. |
