| 摘要 |
PROBLEM TO BE SOLVED: To overcome the problem that a difference is made in a detected distance in long-distance detection and short-distance detection, and it is necessary to largely provide segment area of Fresnel shape in order to condense much more radiated infrared rays from a detection object area on a pyroelectric element in the long-distance detection, and it is necessary to largely provide the segment area of the Fresnel shape similarly in a segment for short-distance detection, consequently, a projection detection area becomes small from the relationship of the detected distance, and segment arrangement in a dense state becomes difficult from the relationship of segment layout in the projection detection area, and then area of an insensitive band area between adjacent detection areas becomes large. SOLUTION: In order to decrease the insensitive band area during the short-distance detection, Fresnel shaped lenses are closely arranged in a segment for long-distance detection, and convex lenses are closely arranged in the segment for short-distance detection, and lenses having different shapes are integrally molded. COPYRIGHT: (C)2010,JPO&INPIT
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