| 摘要 |
PURPOSE:To detect the existence of a detected body effectively by providing a fixed pair of transducers on a piezoelectric substrate and by detecting a reflected wave from the flank of the substrate. CONSTITUTION:On piezoelectric substrate 11, transducer 12 converting an electric signal into an elastic surface wave and transducer 13 converting this received elastic wave into an electric signal are arranged opposing each other at a fixed interval. Then, substrate 11 is held at 90 deg. accurately so as to improve a reflection coefficiency at its flank. For detection, signal supply 14 is connected to transducer 12 to supply a pulse signal; and output circuit 15 is connected to transducer 13 and elastic detected solid body 16 is made in contact with one flank of substrate 11. Since a surface wave propagating from transducer 12 to one terminal of substrate 11 is damped by this solid body 16, a reflected wave arriving at transducer 13 is displayed being damped, so that the existence of solid body 16 will be detected. |
