US Patent 7281805 Projection-type display apparatus

A thin-shaped projection-type display apparatus capable of displaying a high-quality image without causing any ghost image is provided. The projection-type display apparatus includes a screen having a prism, and a projection optical system for guiding image light to the screen. The projection optical system includes a plurality of optical elements. An optical element disposed nearest to the screen on an optical path of the image light among the plurality of optical elements is a mirror. An angle made by the normal to a surface of the mirror approximately at the center of the mirror and the normal to a surface of the screen is between 75 degrees and 87.5 degrees inclusive.