HYDRODYNAMIC AIR BEARING TYPE OPTICAL DEFLECTOR

摘要

PROBLEM TO BE SOLVED: To provide a hydrodynamic air bearing type optical deflector which keeps stable rotary condition without lowering of bearing performance even when thermal deviation occurs on the whole bearing, or by suppressing thermal deviation over all the bearing. SOLUTION: In the hydrodynamic air bearing type optical deflector, a gap between a fixed shaft and a rotary shaft of a pump mechanism located near a fixed shaft which is exposed to the outside of a case, is designed wider than a gap between a fixed shaft and a rotary shaft of a radial hydrodynamic air bearing. Besides an axial flow generation mechanism for generating axial flow is provided on or near the radial hydrodynamic air bearing in order to cool the air supplied to the axial flow generation mechanism through an exhaust hole which is used to exhaust the air in the case to the outside with a pump mechanism.