| 摘要 |
PURPOSE:To obtain high diffraction efficiency by providing the titled element with a back electrode formed on the back of an ultrasonic transducer which is opposed to its combined face and an ultrasonic wave control layer formed on the back electrode and consisting of a metallic material using copper as a main component and having thickness distribution. CONSTITUTION:Electric energy outputted from a driving power supply 18 is impressed to a common electrode 13 and the back electrode 14 formed on both the sides of the ultrasonic wave transducer through lead wires 22, 23 and converted into mechanical vibration. A part of the converted mechanical vibration is projected to the AO medium 11 side as ultrasonic waves and the residual is transmitted to the ultrasonic wave control layer 17. The ultrasonic waves transmitted into the ultrasonic wave control layer 17 formed on the back electrode 14 and consisting of the metallic material having thickness distribution and using copper as a main component are reflected on the opposite face, transmitted again into the transducer 12, made incident upon the AO medium 11, and then superposed to the ultrasonic waves directly projected from the transducer 12 to the AO medium 12. Consequently, the intensity distribution of the ultrasonic wave bundle can be improved and the diffraction efficiency can be sharply improved.
|
