| 摘要 |
PURPOSE:To improve S/N by simple constitution, by arranging a multiple, mountain-like, uneven portion, which top portions are acute angles, to a base of a smoke sensing chamber. CONSTITUTION:A mountain-like, uneven portion 1C, which top portions are acure angles, is mounted in a multiple streak shape to a portion where effective beams from a luminous element 4 are irradiated and a portion where scattered lights are irradiated on a base of a cover 1. The effective beams and the scattered lights are approximately attenuated by means of the mountain-like, uneven portion, and the advance of the beams and lights toward a light receiving element 5 is directly obstructed. When smoke enters, the beams from the luminous element 4 are scattered by smoke, and the scattered lights are projected to the light receiving element 5. |
