| 摘要 |
<p>PURPOSE:To ensure safety for workers and for passersby when a vehicle is running under normal conditions. CONSTITUTION:A transmission means 1 includes a PLD(pulse laser diode) to transmit pulse beams whose output level can be varied. A reception means 2 receives the pulse beam (reflected pulse beam) transmitted from the transmission means 1 and reflected by a reflector. A distance measuring means 3 measures the distance to the reflector according to the transmitted and reflected pulse beams. An output control means 4 comprises an arithmetic unit 5 and an emission circuit 6. The arithmetic unit 5 computes the output level of the pulse beam to be transmitted from the transmission means 1, according to the distance to the reflector which is measured by the distance measuring means 3. The output level of the transmitted pulse beam is preset to be proportional to the distance so that, when the distance is zero, the level is low. The emission circuit 6 drives the transmission means 1 according to the output level of the transmitted pulse beam which is computed by the arithmetic unit 5.</p> |
