| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a passive infrared detector which is provided with a function to prevent an erroneous detection due to a background noise such as disturbance light or the like, whose detecting directivity is almost eliminated and by which an object moving to any direction can be detected surely. SOLUTION: Prescribed detecting areas 7a, 7b, 8a, 8b are allocated by an optical system 4 to one pair each of infrared detecting elements 2a, 2b, 3a, 3b with which a first detecting element pair 2 and a second detecting element pair 3 are provided and whose polarity is opposite. The detecting areas 7a, 7b by the pair of infrared detecting elements 2a, 2b in the first detecting element pair are arranged so as to be side by side along a first direction X. The detecting areas 8a, 8b by the pair of infrared detecting elements 3a, 3b in the second detecting element pair are arranged side by side along a second direction Y which is nearly at right angles to the first direction X. An object is detected on the basis of the logical sum of a detection signal from the first detecting element pair 2 and a detection signal from the second detecting element pair 3.</p> |
