Scanning optical system

摘要

A scanning optical system is disclosed in which a beam once deflected by a first deflector is again scanned by a second deflector which is different from the first one. In the scanning optical system of the invention, the beam once deflected by the first deflector is scanned in a plane normal to the reference deflection plane which is formed by the normal of deflection surface of the second deflector when the latter rotates. This assures that the beam deflected by the second deflector is contained in a plane which forms always a definite angle relative to the reference deflection plane of the second deflector.