| 摘要 |
1. Reflexion light barrier comprising a light source assembly (13) and optical elements (15, 33, 35) to generate two light beams directed along separate optical axes (29, 30), and a photodetector to receive light reflected by a reflecting object, the axis of one light beam extending substantially parallel to the direction of reception (27) of the photodetector, characterized in that the optical elements (15, 33, 35) are designed and located in such way that the axis (30) of the other light beam is at an acute angle to the axis of the first light beam (29). |
