Laser optical proximity fuse detector for missile - uses AND=gate to trigger explosive charge when delayed direct and reflected signals are present

摘要

Short duration pulses at high frequency are emitted by a laser diode (12) driven from a high speed switching circuit (13). This laser is located in a nose cone directly behind a convergent meniscus lens to produce a slightly divergent beam. A photodiode (14), matched to the laser, is located behind a filter (15) to receive light reflected from an annular lens. A fraction of the transmitted light is directed by an optical fibre (18), acting as a delay line, to a second photodetector (19) which comprises a PIN diode. The diode output is applied to an amplifier which also provides waveform shaping. The outputs of this amplifier - and a similar amplifier at the the photodiode output - are applied to AND gate which drives a firing circuit for the explosive if three successive luminous pulses are received.