DEVICE BUILT AROUND LASER FOR METERING DISTANCE TO COMPOUND TARGET AND/OR LIQUID LEVEL Russian patent published in 1998 - IPC

FIELD: metering distance to compound target and/or liquid level. SUBSTANCE: device built around laser diode has laser-diode unit 10 incorporating laser diode and photodiode that emits light 17 onto lens 19 forming collimated beam 20 incident onto float 22 which is coated with reflecting tape on its top surface 24. Beam 20 is reflected from float 22 back to unit 10 and forces the latter to transmit signal incorporating pulses of value corresponding to distance L to float 22 on line 15 to liquid-level metering circuit 14. Optical intensity feedback is formed in the action. Laser-diode unit 10 is excited by sawtooth signal. Distance metering circuit 14 cuts off feedback signal during intervals in laser diode excitation signal. Float may be eliminated and replaced by tube 11 of rather small size to form curvature on liquid surface 250 to attain meniscus effect which forms curved reflecting surface for permanent reflection of incident beam 20 back to unit 10. EFFECT: reduced interference in the form of stains; reduced hardware requirement for signal processing; reduced distortions in metering distance due to noise. 12 cl, 9 dwg