An off-axis image projecting system at least has an illumination source, a reflective displaying device, a projecting lens set, and a first plate. The illumination source emits an illuminating beam. The reflective displaying device can modulate the illuminating beam to form a reflected image-formation beam. The projection lens set has a light path. The reflected image-formation beam enters the projecting lens set, and the first plate is disposed on the light path between the projecting lens set and the reflective displaying device. The illuminating beam from the illuminating source is incident onto the first plate, and then the first plate reflects the illuminating beam to the reflective displaying device by a non-zero incident angle. The reflected image-formation beam can travel through first plate and enter the projection lens set.

A projection type image display apparatus using a small light valve, particularly a liquid crystal light valve, to achieve high brightness, a sharp contrast and excellent uniformity in image displaying. The apparatus includes a light source with a light emitting area, an oval mirror to reflect the light from the light source and a light valve to control the reflected light. The oval mirror possesses two focal points, a first focal point located on one side of the light valve near the oval mirror and a second focal point located on the opposite side of the light valve. The light emitting area is situated at a position so as to include the first focal point of the oval mirror. When the distance, from the first focal point to the light valve which governs the effective light flux area of the light valve is defined as `L` and the distance from the first focal point to the second focal point is defined as `2C`, the relationship between `L` and `C` satisfies the following inequality:

Multimedia projectors (90, 120) include a light source (32) for propagating illumination through a color modulator (42) and a light integrating tunnel (94). Lenses (100, 106) image the integrated light through a patterned-silvered mirror (104, 126) and onto a micromirror display device (MDD) (76, 122). Micromirrors in the MDD that are tilted to an image-forming angle, reflect the image-forming light back toward the patterned-silvered mirror, which propagates the image-forming light toward a projection lens (110). The patterned-silvered mirror includes an accurately positioned boundary separating transparent (102, 116, 128) and reflective (108, 124) portions, resulting in improved contrast of the projected image.

An optical projection system includes a non-point white light source for emanating a white light, a source lens for focusing the white light, a source stopper having a source aperture for shaping the white light into a predetermined configuration, an optical means having a reflection surface for reflecting the white light, a field lens for collimating the white light, an array of M.times.N thin film actuated mirrors for changing the optical path of the white light reflected therefrom, a projection stopper having a projection aperture for passing a predetermined amount of the white light, a relay lens system having a plurality of lenses for modulating the size of the predetermined configuration of the white light, a RGB pixel filter for dividing the white light into the primary light beams, a projection lens for projecting the primary light beams and a projection screen for displaying an image made up of M.times.N number of pixels thereon. In the optical projection system, the RGB pixel filter is disposed between the projection stopper and the projection lens, and hence the white light only has to pass through the RGB pixel filter once, which will, in turn, prevent the lowering of the intensity of the white light and hence the optical efficiency of the system, and it will also cut down the amount of the white light that is reflected away, thereby reducing noises at the projection screen.

This invention provide an image display apparatus having an illumination optical system for effectively illuminating a plurality of areas on a single common plane uniformly by shortening optical paths of the optical system and a new projection optical system capable of reducing the overall size of the optical system and a production cost thereof. The illumination optical system has an ellipse mirror for collecting light beams generated from a light source, a first lens group for suppressing divergence of the light beams reflected from a light collecting area of the ellipse mirror, a plural color filters for separating the light beams into three color light beams and altering a path of each of the three color light beams, and a second lens group for illuminating objects disposed on the single common plane by focusing the separated three color light beams thereon.