| 摘要 |
<p>A passive movement indicator, for the surveillance of an area, comprises at least one sensor (21) of pyroelectric material which receives the radiation (4) from the surveillance area. On the side facing the radiation (4), the sensor is covered with an electrode (215) of a first kind, whereas it is covered with a second electrode (216) of a second kind on the side opposite to the radiation (4). The contact surfaces between the sensor and a substrate (110) are nothing but a fraction of the whole surface. The arrangement of the electrodes of the first and the second kinds as well as the electric connection thereof with resistances (3), are such that there are formed propagation time elements for the displacement of the load, the latter being produced by the radiation (4). A logic circuit (14) calculates the impact point of the radiation (4) to the sensor (21) by means of the propagation time differences and/or the amplitude values of the load displacement produced by the radiation.</p> |
