| 摘要 |
PROBLEM TO BE SOLVED: To provide a photoelectric smoke detector capable of suppressing erroneous detection due to stray light such as scattering light.SOLUTION: A photoelectric smoke detector includes: a housing 21 having a plurality of labyrinth form wall parts 23 arranged side by side via a gap which allows a smoke to inflow from the outside and blocks light from the outside; a light emission part 25 for emitting light to the interior of the housing 21; a light receiving part 26 for detecting scattering light due to the smoke that inflows to the interior; and a reflection part 27 for reflecting the light emitted from the light emission part 25. The reflection part 27 includes: a first reflection surface 27a inclined to an optical axis A1 of the light emission part 25; and a second reflection surface 27b for receiving reflection light reflected by the first reflection surface 27a. The side of the light emission part 25 in the second reflection surface 27b is inclined to the side of the optical axis A1, and an end part of the side of the light emission part 25 in the second reflection surface 27a is equal to the distance up to the light emission part 25 or placed in a near distance when compared to the end part of the side of the light emission part 25 in the first reflection surface 27a.SELECTED DRAWING: Figure 2 |
