Oblique projection optical system and projection type display apparatus using the same

摘要

A projection type display apparatus including an oblique projection optical system having a plurality of lenses is disclosed. A lens nearest to a projection screen has a vertical effective image area through which a light flux (3) passes. The lens is arranged at a position not including an optical axis (11) shared by the largest number of lenses among the plurality of lenses. A flat mirror (14) for returning the optical path is arranged between the particular lens and the projection screen at a predetermined angle to the optical axis (11). An enlarged image obtained by the light flux (3) returned by the flat mirror (14) is formed toward a display screen.