| 摘要 |
PROBLEM TO BE SOLVED: To add water-proof and dust-proof functions to a fire sensor while suppressing a cost increase and degradation of appearance of a light emission part of the fire sensor.SOLUTION: A fire sensor 10 is provided with: a dome-shaped main body case 11 having an opening at a center of a housing; a back surface cover member 12 mounted on the main body case 11; and a light transmission window member 14 that blocks the opening. A light emission part 15 is provided with: an annular light emission part 15a disposed along an edge of the opening; a light introduction part 15c provided so as to extend in a tangential direction of the annular light emission part 15a; a rod-formed light incidence part 15b that makes light from a light source enter into the light introduction part 15c; and a reflection part 15d provided at a joining part between the light introduction part 15c and the light incidence part 15b and capable of reflecting the light from the light incidence part 15b toward the light introduction part 15c. A through hole, in which the light incidence part 15b is inserted, is formed in the main body case 11. An O-ring 20, which is capable of sealing a gap between the through hole and the light incidence part 15b, is insertion-fitted around the light incidence part 15b.SELECTED DRAWING: Figure 1 |
