| 摘要 |
The optical presence detector sender and receiver lobes overlap each other within an area. The level of the signal from the receiver is used to ascertain whether an object is detected or not. The receiver sensitivity is suitable for detecting a dark object within the whole detection area. The sender and receiver lobes emerge from points at a specific distance from each other. The area within which the object is detected coincides with the area where the sender lobe coincides with the receiver lobe, and is defined in an angle direction, relatively to a plane which includes the receiver lobe centre line and the sender. The lobes are limited to a level taken up by the receiver output signal to at most a twentieth part when the object is moved in a direction away from the receiver. |
