Patent ID: 7535648

Claim:
A projection type image display for projecting, in enlarged form onto a projection screen, an image displayed on a display screen of an image display element, the display comprising: a first optical system including a plurality of lenses for enlarging the image displayed on the display screen; and a second optical system that causes image light of the image from the first optical system to reflect and then enter the projection screen at a required angle with respect to a normal of the projection screen; wherein the first optical system includes at least one asymmetric lens whose surface shape is concave in an emission direction of the light and rotationally asymmetric with respect to an optical axis, the asymmetric lens being installed in a lens barrel such that among the edges of the lens in the vertical direction of the lens, one edge from which the image light is emitted to the second optical system at a large angle is used as a reference edge, and such that the other edge from which the image light is emitted to the second optical system at a small angle is used as a movable edge; wherein the second optical system includes at least one convex mirror whose reflection surface has at least one portion forming a convex shape in a direction of the reflection; and wherein the first optical system includes a projection lens formed of a plurality of lenses including the asymmetric lens, the projection lens being adapted to include not only a front group that includes a lens of a surface shape symmetric to an optical axis, but also a rear group that includes the asymmetric lens.