Patent ID: 8182101
Filing Date: 2012-05-22
Classification: G02B,G03B,H04N

Abstract:
1. An illumination optical system comprising: an integrator configured to divide light from a light source into plural light fluxes; and a collection optical system configured to collect the plural light fluxes from the integrator toward an illumination surface, the collection optical system comprising a first optical unit having a positive optical power and a second optical unit disposed closer to the illumination surface than the first optical unit and having a positive optical power, the distance between the first optical unit and the second optical unit is the longest air interspace distance in the collection optical system, wherein a rear principal point of the collection optical system is located closer to the light source than a front principal point of the collection optical system, and wherein the following condition is satisfied: where Fc represents a focal length of the collection optical system, and F