RANGE FINDING DEVICE UTILIZING PHOTODETECTION QUANTITY DETECTION SYSTEM

摘要

PURPOSE:To take a precise range measurement up to a distant point with small light projection energy by varying continuously the projection frequency of infrared light projected on a target body within a specific frequency band. CONSTITUTION:An oscillation circuit part 11 supplies a modulated signal whose frequency is varied continuously by a control circuit part 20 within a specific- width frequency band to a projection part 1 through a driving circuit 8 to project infrared light Y from an LED7 upon the target body X. Reflected light Z from the body X is photodetected by the photodetection sensor 31 of a photodetection part 3. Its photodetection signal output also corresponds to frequencies within the frequency band and part of the photodetection signal which varies in frequency within the specific frequency band resonates through a resonance circuit 4. Its output signal is amplified 34 and a range signal generating circuit 37 outputs a desired range signal through a peak holding circuit P. Consequently, resonance operation is utilized extremely effectively without complicate frequency matching between the projection and photodetection sides and stable range finding operation is performed.