| 摘要 |
<p>PURPOSE:To speedily and accurately adjust the operation point of the detection sensor without any operator's intervention by using a voltage, at which a decision result is inverted while the quantity of light emission of a light emission device is made less than usual, as the threshold voltage of a comparator. CONSTITUTION:The light emitting diode 1 of an inspection sensor is supplied with a necessary current from a light emission quantity control means and the light emitted by the diode turns on a phototransistor 2. The voltage which is generated as a result is applied to one input terminal of a comparing means 3 and the variable voltage Vs which is generated by a voltage control means 5 is supplied as the threshold voltage (reference voltage). The comparing means 3 compares them with each other and supplies its comparison result signal to a decision means 4. A control part 6 sends commands to a variable source voltage control means 5 and the light emission quantity control means 7 respectively according to the decision result of the decision means 4.</p> |
