Device for measuring distances particularly aircraft door clearances measures intensity of light beam passing through polarizer, magneto-optical film and analyzer in presence of adjacent magnetic field

摘要

The separation (d) between two parts is measured by attaching magnet (1) to first part (2) and electro-optical unit (3) to other part (4). Diode (9) emits a beam (8) which passes through a polarizer (6) a magneto-optical film (5) and an analyzer (7) to a receiving photodiode (10) and processor (11). The effect of the magnetic field on the light intensity enables distance (d) to be determined.