| 摘要 |
A light scattering type smoke sensor has a plurality of labyrinth members 9 for facilitating an inflow of smoke entering from the outside, and for cutting off light entering from the outside; a smoke detecting chamber which is formed in a center portion by the labyrinth members; light emitting device 12 for radiating light toward the smoke detecting chamber; and light receiving device 13 for detecting light which is scattered by the smoke in the smoke detecting chamber, the light receiving device having an optical axis which intersects the optical axis of the light emitting device at a scattering angle in the range of 60 to 80 DEG , wherein one of the labyrinth members 91 intersects the optical axis of the light emitting device, and has a reflecting face 91b for reflecting light radiated from the light emitting device, in a direction opposite to the light receiving device. Preferably the member 91 is at 45 DEG to the optical axis of the light emitting means and the projecting area of the emitting means is within a height of the member 91. <IMAGE> |
