| 摘要 |
PURPOSE:To enhance reliability by preventing the emission of an erroneous signal, by a method wherein a piezoelectric body is held between a pair of electrodes and another one electrode is further provided in a side receiving pressure contact force and impact force from the outside so as to hold a definite distance from the surfaces of said electrodes. CONSTITUTION:When matter which has kinetic energy equal to or more than a definite level collides with an isolation electrode 3, a part of the isolation electrode 3 provided under tension is depressed to the side of an electrode 2 and, simultaneously with the contact of the surface of the isolation electrode 3 with the electrode 2, the surface of a piezoelectric body 1 is struck and piezoelectric charge is generated in the piezoelectric body 1. This piezoelectric charge transfers to the electrode 2 and the isolation electrode 3 and is detected from electrode terminals 5, 5' as voltage. This detected voltage is determined by the value of the piezoelectric charge. Therefore, the voltage corresponding to the magnitude of impact can be detected and, when a small quantity of sand is fallen, no voltage is generated. By this method, the emission of an erroneous signal is prevented to make it possible to enhance reliability. |
