Optical enclosure for high speed rotating beam deflector

摘要

A non-rotating optical shield is generally cylindrical in shape and surrounds a rotating optical deflector to reduce airflow and optical distortion, as well as acoustic noise. A beam entrance aperture is provided in an end of the shield allowing an input beam to project onto the rotating deflector along the deflector's spin axis. The entrance aperture is sealed by a window to prevent air from being drawn into the shield by the action of the rotating optical deflector. The deflected beam exits the shield through a beam exit aperture in the side of the shield which is enclosed by an optical element. Clearances between the shield and the rotating deflector are minimal. The shield reduces temperature gradients in the surrounding air thus reducing optical distortions caused by changes in refractive indices of the deflector and surrounding air. An additional feature of the shield is a fan-like portion which extends radially outward from the cylindrical body portion of the shield at the beam exit aperture, to enclose the exit beam as it scans through as range of angles. The fan-like portion extends as far along the exit beam path as desired and advantageously reduces acoustical noise generated by the rotating optical deflector.