| 摘要 |
<p>PURPOSE:To constitute many detection lines and to detect a small body over a wide range by detecting continuous pulse light from plural light emitting elements and maintaining the detection state for a constant time by using a delay circuit. CONSTITUTION:When pulses generated by an oscillator 4 are frequency-divided by a frequency divider 5 and inputted to a counter 6, the counter 6 distributes its count output in order to make light emitting elements 3a - 3e emit light in order through AND gates 7... 7 and drivers 8... 8, thereby generating the continuous pulse emission state on the whole by the plural light emitting elements. Light receiving elements 9a - 9e installed opposite the elements 3a - 3e are positioned within the irradiation angle range of the respective light emitting elements to perform detection at all times, and receive continuous pulse light unless a body to be detected is present. Here, if the body to be detected cuts off one detection light and the element 9a is shielded by one constant pulses, its light reception signal is absent and the delay circuit 10 operates to turn off the output for the constant time. Then an output circuit 11 outputs the body detection state for the constant time.</p> |
