APPARATUS AND METHODS UTILIZING BREWSTER ANGLE FOR DETERMINING ANGULAR VELOCITY AND LIGHT BEAM INCIDENCE ANGLES

摘要

A light beam linearly polarized in its plane of incidence is projected onto the peripheral surface of a rotatable refracting disc at an angle that effects absorption of all the incident light. Means for detecting reflected light are positioned proximate to the point of incidence. Angular velocity of the disc is determined by the amount of change in angle of incidence of the light beam required to eliminate any light reflected due to disc movement. Change in angle of incidence of the light beam is measured by rotating the disc to a speed that eliminates any light reflected due to such change in angle of incidence.