A compact optical scanning apparatus includes a motor driven hollow drive shaft through which scanning light beams are projected. A mirror mounted on one end of the drive member deflects the light beams to the side of the drive member, said light beams impinge on the interior surfaces of a conically...http://www.google.com/patents/US5149949?utm_source=gb-gplus-sharePatent US5149949 - Optical scanner with counterrotating reflector elements
