Rotating beam deflector having an integral wave front correction element

摘要

An inclined mirror (22) is provided in a cylindrical housing (16) which has an open end (30) and a closed end (18). An optical planar glass plate (34) or window is mounted at the open end of the cylindrical housing. A laser beam (26) enters the housing through the window and is reflected off the inclined mirror. The reflected beam (32) leaves the housing through a side aperture (28) in the housing. The cylindrical housing is rotated to scan the beam through a range of angles. Rotation of this optical system induces astigmatism in the beam due to the deformation of the inclined mirror at high rotational speed. If the window is tilted so that the entering laser beam is no longer normal to the window surface, then the window will induce a degree of astigmatism in the laser beam. The angular position of the window can be adjusted relative to the inclined mirror, thus compensating for the dynamic astigmatism due to rotation. <IMAGE>