PROJECTION LENS, PROJECTION DISPLAY EMPLOYING THAT PROJECTION LENS, AND REAR PROJECTION DISPLAY

摘要

A projection lens exhibiting a good aberration performance while employing a front projection and capable of realizing the specifications required for a projection display, i.e. a low F number, a wide angle, a long back focus and a high quantity ratio of peripheral light, through a rational arrangement. The projection lens (1), for projecting an optical image formed on a spatial light modulator element (located in the vicinity of an image plane (5)) while enlarging onto a screen (4), consists of a front lens group (2) and a rear lens group (3) located sequentially from the screen (4), side toward the image plane (5) side. The rear lens group (3) is provided with a diaphragm (6) decentering from an optical axis (7) common to the front lens group (2) and the rear lens group (3). Focus is adjusted by moving the rear lens group (3) in the direction of the optical axis (7) without turning it.