Patent ID: 8408717

Claim:
A projection type image display apparatus, comprising: a first lens group including a plural number of lenses being disposed in a direction of propagation light with respect to an image display element; a second lens group including a plural number of lenses being disposed in a direction of propagation light with respect to said first lens group; a reflection mirror, which is configured to reflect light emitted from at least one of said first and second lens groups, so as to project the light obliquely upon a screen; wherein a ratio (Lo/Lp) of a diagonal size (Lo) of said screen and a distance (Lp) from a center of said reflection mirror to said screen is at least 2; wherein said second lens group includes a refractive lens having a negative power and a rotationally symmetric surface configuration; wherein the second lens group is configured to enable movement of at least one lens of the second lens group with respect to the first lens group.