| 摘要 |
The detector (2) has a transmitter (4) transmitting light beams, and a receiver (8) e.g. photodiode, receiving the beams reflected by a reflector (6) e.g. retro-reflector. An exploitation circuit (11) receives characteristic signals of the transmitted and received beams, and generates a smoke detection signal based on the signals. A mask (12) is placed adjacent to the reflector and selects the beams having a transmission direction (E) belonging to a predefined angular range in a given axial plane. The mask is made of opaque plastic material, and has an absorption unit and tubes (14). |
