A color integrating optical device for integrating different color rays from a plurality of display devices each of which has a condenser lens in front thereof and emitting the integrated color rays to a non-telecentric projecting optical system, including a dichroic mirror plate having a dichroic film, the dichroic mirror integrating the color rays by the dichroic film in which a color rays from one of display devices reflects thereon and another color rays from the other of display devices transmits thereon, the dichroic film being formed an incident surface of a color rays to be reflected, and a dummy plate provided on an optical path of color rays to be reflected by the dichroic film so that an unnecessary rays caused by part of the color rays being reflected at the dummy plate does not emit to the non-telecentric projecting optical system.
Color integrating optical device and display optical system