| 摘要 |
PURPOSE:To impart self-diagnostic function, by providing a light emitting element for detecting the abnormality of an apparatus, to which light can be incident, in opposed relation to the light receiving element of a reflective type obstacle detecting apparatus, and automatically driving the light emitting element for detecting abnormality when the output of the light receiving element is lowered. CONSTITUTION:A light emitting diode LED1 for detecting an obstacle is provided to a light emitting part 10 and light L1 is allowed to project toward the outside through a window 11. When there is an obstacle in the radiation range of light L1, reflected light L3 is incident on a light receiving element, for example, a photodiode PD through the window of a light receiving part 20. LED2 for self-diagnosis is provided to the light emitting part 10 and an oscillator 12 applies modulation to output lights of LED1 and LED2 connected in series. LED2 is driven only for a period when a parallel switch SW is opened. The circuits of the light emitting part 10 and the light receiving part 20 are partially received in a chamber 30 and the windows 11, 21 are inclined to a mutually opposed direction so that direct light L2 of LED2 is easily incident on PD. When incident light of PD is reduced, the output (b) of a comparator 24 comes to L and the switch SW is opened to enable self-diagnosis. |
