| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a small size smoke sensor capable of reducing erroneous detection due to insects and/or dust. <P>SOLUTION: A smoke sensor 1 includes: a smoke detection chamber 2 that prevents outside light from coming therein while allowing smoke to come therein/go out therefrom; light emitting parts 3a and 3b each of which projects a light beam to each of plural detection areas A1 and A2 in the smoke detection chamber 2; a light receiving part 4 in which direct light from the light emitting part 3a or 3b does not enter but which is sensible to scattered light due to smoke entered into the detection areas A1 and A2; and a determination part 5 that determines existence/absence of smoke on the basis of the output from the light receiving part 4 when only the light emitting part 3a is turned on and the output from the light receiving part 4 when only the light emitting part 3b is turned on. Each of the light emitting parts 3a and 3b has a light restriction member 11 formed integrally therewith for restricting each of irradiation ranges S1 and S2 of the emitted light so that detection areas A1 and A2 do not overlap with each other. The light receiving part 4 has a light restriction member 12 formed integrally therewith for restricting an irradiation range S3 of the reception light so that the detection areas A1 and A2 do not overlap with each other. <P>COPYRIGHT: (C)2013,JPO&INPIT |
