A projector is provided wherein the shapes of rod integrators for the respective colors (i.e., the shapes of the output ports thereof) are made nearly the same as the shapes of the effective pixel regions and the sizes of the output ports of the rod integrators for the respective colors are made slightly larger than the sizes of the effective pixel regions of the liquid crystal light valves opposed thereto. As a result, uniform illumination light output from the output ports can be caused to enter the effective pixel regions with no loss or damage to uniformity.

An illumination system includes an illumination unit having at least one light emitting device which emits a light beam of a predetermined wavelength and at least one holographic optical element which reduces a cross section of the light beam emitted from the light emitting device, and an optical path changer which changes a proceeding path of an incident light passing through the holographic optical element. A projector includes at least one illumination unit having at least one light emitting device which emits a light beam of a predetermined wavelength and at least one holographic optical element which reduces a cross section of the light beam emitted from the light emitting device, an optical path changer which changes a proceeding path of an incident light input through the holographic optical element, a display device which forms an image by processing a light beam input from the optical path changer according to an image signal, and a projection lens unit which magnifies the image formed by the display device and projects the magnified image toward a screen.

In the rear of a liquid crystal display arranged with an inclination to a line of sight reflected by a concave mirror, a backlight and a focusing lens member are arranged in such a manner that the backlight and the focusing lens member are positioned on a plane perpendicular to the line of sight reflected by the concave mirror, and the focusing lens member focuses beams of illumination light from the backlight in such a manner that the beams of illumination light stays within a range of the liquid crystal display.

An illumination system includes at least one light emitting device to emit a light beam having different wavelengths, a focusing lens to condense the light beam emitted from the light emitting device, and a waveguide having an incident surface inclined at a predetermined angle upon which the light beam condensed by the focusing lens is incident. A projection system includes at least one light emitting device to emit a light beam having the different wavelengths, a focusing lens to condense the light beam emitted from the light emitting device, a waveguide having an incident surface inclined at a predetermined angle on which the light beam is condensed by the focusing lens, a display device to form an image by processing the light beam passing through the waveguide according to an input image signal, and a projection lens unit to magnify the image formed by the display device and to project the magnified image toward a screen.

An illumination apparatus comprises an illuminant which radiates diffused light from an outgoing plane and generates heat, a light guiding member configured to guide the diffused light from the illuminant while reflecting the diffused light at the internal surface thereof, and a holding member configured to integrally hold the illuminant and the light guiding member at a predetermined interval. The light guiding member includes an incident end which is close to the outgoing plane of the illuminant, and into which the diffused light is incident and which is larger than the outgoing plane of the illuminant, and an outgoing end which is larger than the incident end. The holding member includes a heat conducting portion configured to conduct the heat generated at the illuminant, and a heat radiating portion configured to radiate heat from the heat conducting portion.