Corresponding to the precaution range adjustment mannered null

摘要

PPROBLEM TO BE SOLVED: To easily regulate a warning range without using a complicated configuration in a passive infrared sensor. PSOLUTION: The passive infrared sensor is provided with two condensing optical systems of a first optical system 31 and a second optical system. Each of the two condensing optical systems is composed of a plurality of Fresnel lenses. First and second elements 32 and 42 are arranged in response to the first and second optical systems 31 and 41 respectively. A detection optical path and a detection zone are arranged by the elements and the condensing optical systems as predetermined. A desired Fresnel lens of the first optical system 31 and/or a desired Fresnel lens of the second optical system 41 are masked by a masking member M. PCOPYRIGHT: (C)2006,JPO&NCIPI