| 摘要 |
PROBLEM TO BE SOLVED: To provide a fire alarm that can increase the quantity of detection light radiated to a predetermined radiation area in a smoke detection space without increasing the radiation area. SOLUTION: The fire alarm 1, which has the smoke detection space 32 into which external smoke flows and a light emission part 33 for emitting detection light to the smoke detection space 32, is provided with a radiation area restriction structure 35 for restricting the radiation area of the detection light in the smoke detection space 32 which has an opening 350 through which the detection light passes from the light emission part 33 to the smoke detection space 32 and a light guide space 351 through which the detection light emitted from the light emission part 33 passes to the opening 350. The light guide space 351 is open such that all the detection light emitted from an outer surface of the light emission part 33 to the opening 350 reaches the opening 350 without interruption. COPYRIGHT: (C)2009,JPO&INPIT
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