| 摘要 |
PURPOSE:To obtain a convergent beam with deep focal depth by fitting an acoustic lens having a curved surface to a surface of a linear array oscillator, or by phase-driving the linear array oscillator. CONSTITUTION:Impulses having numbers of successive wave surfaces are generated in such a way that focuses distributed successively on a center axis which crosses the array direction of a linear array oscillator 31 at right angles and is positioned in the center of the oscillator are multiplied through an acoustic lens 23 respectively, thus converging an acoustic wave beam. In another way, each oscillator of the linear array oscillator 31 is phase-driven with adequate delay time without using said acoustic lens 32, thereby generating impulsive wave surfaces. Consequently, the wave surfaces having focuses distributed within a certain range are generated, so a convergent beam with deep focal depth is obtained. |
