Projection system and projector

Abstract

A projection system including seven lens groups sequentially arranged from an enlargement side, a first lens group having negative refractive power, a second lens group having positive refractive power, a third lens group having positive refractive power, a fourth lens group having negative refractive power, a fifth lens group having positive refractive power, a sixth lens group having positive refractive power, and a seventh lens group having positive refractive power, wherein νdR that is a dispersion value of a lens that forms the seventh lens group out of the seven lens groups and is closest to a reduction side and νdF that is a dispersion value of a lens that forms the first lens group out of the seven lens groups and is closest to the enlargement side satisfy a following conditional expression: 5<νdR−νdF<30.

Dependencies are inferred from the claim text.