| 摘要 |
<p>In an installation for transmitting and receiving focused ultrasonic waves a disc-shaped planar oscillator (3) is coupled to a liquid chamber (1). In the liquid chamber (1) there is provided a liquid lens (2) which contains a second liquid. The focal distance of the liquid lens (2) may be varied by acting on the volume of the liquid that it contains. Further, the focus is displaceable in the focal plan for example by regulating the angle of the planar oscillator (3) with respect to the optical axis of the liquid lens (2) or by excentric rotation of the liquid lens (2) with the planar oscillator (3).</p> |
