| 摘要 |
<p>PURPOSE:To allow effective lighting of illuminator by switching and updating the OFF delay time such that it is lengthened when a human body enters into the coverage of detecting beam and a detection signal is outputted whereas it is shortened when the human body departs from the coverage of detecting beam and a detection signal is outputted. CONSTITUTION:When a human body traverses a detecting beam, a positive detection signal is outputted to produce an ON signal and a long OFF delay time is previously set but a negative detection signal is outputted immediately thereafter to produce an ON signal and the preset OFF delay time is reset to a short one. When the human body enters into the coverage of detecting beam and stays therein, a positive detection signal is outputted to produce an ON signal thus setting a long preset OFF delay time which is not updated thereafter. Consequently, control signal is not turned OFF so long as a person stays in the detection area but it is turned ON quickly upon retreat of the person from the detection area thus avoiding useless lighting of illumination.</p> |
