| 摘要 |
<p>PURPOSE:To provide a pyroelectric infrared detector in which a signal due to a human body can be distinguished definitely from a signal based on disturbance by producing output from two paris of dual elements while reversing the polarity with respect to the motion detecting direction. CONSTITUTION:Light receiving elements (a), (b) and (c), (d) having identical shape and light receiving area are arranged symmetrically and closely each other to form a pair of dual elements I (II) of elements (a), (b) and (c), (d). The dual elements I, II are arranged to produce outputs with reverse polarity with respect to the motion detecting direction and an FET is wired simultaneously. For example, the minus electrodes of the elements (a), (b) are interconnected and the plus electrodes thereof are connected, respectively, with an FET F1 gate and the earth terminal G. On the other hands, the plus electrodes of the elements (c), (d) are interconnected and the minus electrodes thereof are connected, respectively, with an FET F2 gate and the terminal G. Since the signals S1, S2 from the dual elements I, II exhibit reverse polarity for the motion of a human body and the same polarity for high frequency disturbance, they can be distinguished definitely.</p> |
