| 摘要 |
A smoke detector, in which there is provided a light emitting portion (2) for throwing a beam of light onto smoke entering into the detector, and a light detecting portion (3) arranged to receive light having been scattered from particles of the smoke. The light emitting portion comprises a light source (5) and a light pervious sphere element (6a) permitting passage of a beam of light from the light source toward the smoke, while the light detecting portion comprises a light sensitive element (9), generating a smoke detection signal in response to the detection of the scattered light and a light pervious sphere element (6b) permitting passage of the scattered light toward the light sensitive element. In the case where invisible light, such as infrared rays, is employed, the light detecting means comprises a light selecting member. |
