Patent ID: 6366398
Filing Date: 2002-04-02
Classification: G02B

Abstract:
An observation apparatus having an objective system with an interchangeable objective unit and a tube lens unit set at a position to which a light beam is guided from said objective unit, thereby forming an observation image of an object at a predetermined magnification via said objective and tube lens units, comprising:a stage capable of allowing said object to be held on a major surface thereof; a revolver to which a partial objective unit constituting part of said objective unit can be attached, said revolver setting said partial objective unit attached to said revolver at a first position on an optical axis of said objective system between said stage and said revolver; an auxiliary lens unit constituting said objective unit together with said partial objective unit set at the first position when said auxiliary lens unit is positioned at a second position on the optical axis of said objective system between said revolver and said tube lens unit positioned on an opposite side of said stage with respect to said revolver, wherein, when said objective system is constituted by said partial objective unit set at the first position, said auxiliary lens unit set at the second position, and said tube lens unit, a composite lateral magnification &bgr;a of said objective system satisfies the following condition: |&bgr;a|&lE;1.5; anda driving mechanism for changing a position of said auxiliary lens unit, said driving mechanism setting said auxiliary lens unit to at least one of the second position and a third position offset from the optical axis of said objective system.