Optical system and projection-type image display device

摘要

In an optical system includes a first prism having a first surface and a second surface forming mutually acute angles, and a second prism having a third surface. The first prism and the second prism forms an air gap between the second surface and the third surface. The air gap formed by the second surface and the third surface is a cross section perpendicular to the first surface and the second surface having a wedge shape which widens at a part near the first surface and narrows at a part distant from the first surface.