Projection type image display apparatus
View Patent ↗A projection type image display apparatus includes an image display element, and a projection optical unit, which is configured to project an image displayed on the image display element, enlargedly, upon a screen. The projection optical unit includes a lens group, which is configured to compensate an distortion on an image surface on the screen, a mirror for compensating a trapezoidal distortion on the screen. The mirror reflects lights emitted from the lens group, so as to project upon the screen obliquely.
1. A projection type image display apparatus, comprising:
an image display element;
a first lens group, being disposed in a light direction with respect to said image display element, which is configured to include a plural number of lenses;
a second lens group, being disposed in a light direction with respect to said first lens group, which is configured to include a plural number of lenses; and
a reflection mirror, which is configured to reflect lights emitted from said second lens group, so as to project upon a screen obliquely;
wherein between a plural number of lenses making up said second lens group, at least one outer shape configuration thereof is an asymmetric circle configuration with respect to an optical axis of a lens;
wherein said first lens group, is disposed beside said image display element, and said second lens group is disposed between said first lens group and said reflection mirror;
wherein an optical path length starting from a final surface of said first lens group and reaching to a reflection surface of said reflection mirror, on a path, along which a central light beam of a projection optical unit including said first lens group and said second lens group propagate directing to said screen, is at least five times a length of a focus distance of said first lens group; and
wherein said second lens group includes a refractive lens having a negative power, which has a rotationally symmetric surface configuration, and further comprising a rod, which is configured to move in the optical direction, with respect to said first lens group.
2. The projection type image display apparatus, according to claim 1 , wherein an optical axis of at least said first lens group is included to a normal line at a center of a surface of said display element.
3. The projection type image display apparatus, according to claim 1 , wherein the following equation is satisfied:
| L 1 −L 2 |<1. 2*sin ⊖ s*Dv;
wherein L1 is distance of a path of a light beam entering from an upper end portion of a reflection surface of said mirror into an upper end portion of said screen, L2 is distance of a path of a light beam entering from a lower end portion of the reflection surface of said reflection mirror into a lower end portion of said screen Dv is distance from the upper end portion of said screen to the lower end thereof, and ⊖s is an angle defined by a central portion of said reflection mirror and the normal line on the screen.
4. The projection type image display apparatus, according to claim 1 , wherein said rod is operable from an outside of said projection type image display apparatus.