| 摘要 |
PURPOSE:To simplify a circuit structure and obtain a low-cost displacement switch by providing two halved photodiodes for receiving light from an object to be measured and for outputting electric signals in accordance with the displacement of the object. CONSTITUTION:A displacement switch is composed of a light source 2 for emitting a light beam L, a light source driving circuit 1 for pulse-driving the light source 2, divided photodiodes 15 and 16 for receiving reflected light L2 and L3 from an object 4 to be measured that is irradiated with the light beam L and for outputting electric signals in accordance with the displacement of the object 4, and the like. The reflected light L3 is irradiated on a region sandwiched by the dividing points 15c and 16c of the photodiodes 15 and 16, respectively, to form a light spot 29 on the region. Photodiodes 15a and 15b and photodiodes 16a and 16b generate voltage signals (current) V1 and V2 and voltage signals (current) V3 and V4 in correspondence with the light receiving positions of the light spot 29 and those voltage signals are compared with each other in comparators 25 and 26, respectively. When the object 4 moves in either direction shown by an arrow A or B and the light spot 29 moves to the dividing points 15c and 16c, the output of a detecting circuit is inverted and it is detected that the object 4 reaches a prescribed displacement range or gets out of it. |
