Inclination monitoring system including reflection of collimated light

摘要

An inclination monitoring system for monitoring an inclination of a lens having a lens portion and a flange portion surrounding the lens portion with respect to a reference plane. The inclination monitoring system includes a light emitting system which emits a collimated light beam towards the lens. The light emitting system and the lens are arranged such that optical axes of the light emitting system and the lens form a first predetermined angle. The monitoring system is further provided with a light receiving system which receives light reflected by the lens. The light receiving system is arranged in a predetermined positional relationship with respect to the light emitting system and the lens. In particular, the collimated light beam illuminates an entire area of the flange portion.