Abstract: A projection display apparatus, which projects a magnified image onto a screen, comprises an image forming system, such as a display panel, a projector including a plurality of lenses for projecting the image onto the screen, and a decentering mechanism for decentering some lenses in the projector with respect to the optical axis. Even if the image is distorted by arrangement of the screen and the optical axis and so on, the distortion is compensated by decentering the lenses and producing a decentering distortion.

Abstract: Mobile refractive optical members are placed in a device between the film and stereoscopic direct viewing windows. A drive is provided for driving the film strip bearing stereoscopic images and the mobile refractive optical members at a uniformly constant speed and in synchronism across the fields of view of the viewing windows to provide a fixed image in each window despite the motion of the film; the film strip has a sound track which may be reproduced by conventional reproduction equipment since the film strip is driven at a constant speed.