| 摘要 |
PURPOSE:To obtain a small and light sound wave transmitter-receiver with high acoustic emission area ratio by applying a compressed bias stress to a cylindrical vibrating element placed in the ball-shaped or spheroidal shell and by giving an absorption vibration towards the radius direction. CONSTITUTION:An annular piezo-electric vibrating element 12 is fitted with an annular supporting material 13 placed around it, and vibrating shells 11, 11' having a part of spherical shell or an ellipsoid of revolution structure the both side of the annulus. Then, the supporting member 13 is tighten in the circumferential direction and compressed bias stress is applied to the piezo-electric vibrating element 12 and shells 11, 11'. In this situation, if the piezo-electric vibrating element 12 vibrates like breathing vibration, the shells 11, 11' generate a vibration of vibration amplitude displacement in the direction of arrows, and the amplitude at around the center is increased larger than that of the radius r direction. If one side of shells 11, 11' is flat, an output to the flat side is removed. This process constitutes a small sound wave transmitter-receiver of high acoustic emission area ratio. |
