| 摘要 |
PURPOSE:To simplify constitution and to enable fine space division so that a small moving object can be detected by providing the 1st pyroelectric element, which is narrower than the width of the opening provided to a support and longer than the length of said opening, in the shape of a bridge, on the broader opening side of the through-hole provided to the support, and providing the 2nd pyroelectric element so as to cover nearly the narrow opening on the narrow opening side. CONSTITUTION:A pyroelectric element 4, with its photodetection surface positioned on a support 5 side, is attached to the narrowed port side of a supporting plate 5 punched with a graded through-hole 8. A pyroelectric element 3 formed with photoelectric electrodes on both surfaces is attached on the broad port side of the support 5 by adhering both ends of the element 3 like a bridge to the plate 5. The element 3 is formed narrower in width than the opening on the broad port side of the hole 8 and longer in length than the opening. If an incident IR ray 6 is parallel, the IT ray made incident from regions A, E is made incident from to the rear side of the element 3, and the IR ray made incident from a region C is made incident to the surface of the element 3. The IF ray made incident from the regions B, D is made incident to the element 4. The detection element itself has a zone dividing function in the above-mentioned way, whereby the constitution is made simple. The fine space division is made possible and a small moving object is detected. |
