| 摘要 |
<p>PURPOSE:To decrease faults which are caused by an electrolyte by applying a voltage which is lower than an operating voltage to a light source or photoelectric converting element in the off period of a sensor and covering the surface of the sensor with a transparent coating material. CONSTITUTION:When a specific current flows from a power source 33, the LED 31 of the photosensor 21 illuminates. The collector of the phototransistor(PT) 32 of the sensor 21 is connected to the base of a transistor(TR) 35 and the emitters of the PT 32 and TR 35 are grounded to obtain an output corresponding to the quantity of photodetection at the collector of the PT 32 and the inverted output at the collector of the TR 35. Consequently, even when the PT 32 is off, the base-emitter voltage of the TR 35 is applied between the collector and emitter of the PT 32 and this voltage is lower than the operating voltage, so even if the electrolyte enters the gap between a mold part and the PT 32, its electrolytic reaction is not active; and the surface of the sensor 21 is covered with the transparent coating film to make the electrolyte hard to enter the sensor, thereby reducing trouble.</p> |
