PROJECTION SYSTEM AND PROJECTION-TYPE IMAGE DISPLAY APPARATUS

A projection system is formed of a first optical system and a second optical system sequentially arranged from the demagnifying side and forms an intermediate image in a position between a demagnifying-side image formation plane and a magnifying-side image formation plane of the projection system. The second optical system is a lens. The lens has a first transmissive surface, a reflective surface, and a second transmissive surface sequentially arranged from the demagnifying side toward the magnifying side. The reflective surface has a concave shape, and the second transmissive surface has a convex shape protruding toward the magnifying side. An imaginary line specified in the lens inclines with respect to an imaginary vertical line perpendicular to the imaginary axis in a plane YZ, and the intermediate image is located in the lens between the first transmissive surface and the reflective surface.