| 摘要 |
PURPOSE:To shorten and reduce the reverberation of an ultrasonic wave oscillated from a microphone by forming a circular opening in the base part of the horn, and forming the tip in an ellipse shape. CONSTITUTION:The cylindrical horn 1 has the circular base and the longitudinally ellipse tip part, and varies continuously from the circular shape to the ellipse shape. The internal diameter of the right cylindrical part of the base part is nearly equal to the diameter of the microphone 2 for ultrasonic oscillation. The microphone 2 covered with a vibration-proof rubber cap 5 is stored in a box body 4 and the microphone 2 is exposed directly. Consequently, a detection area of an ultrasonic wave is made long in one direction and short in the other direction to obtain directivity, and the wave front of said ultrasonic wave from the microphone is never disordered. |
