Abstract: An illumination unit with an improved color synthesis prism, which can synthesize light beams emitted from compact light sources, and a projection type image display apparatus employing the illumination unit.

Abstract: An illuminating unit includes a reflector including a parabolic reflecting surface and an incident portion and an exit portion intersecting with each other a light source to emit a beam onto the reflecting surface through the incident portion, a light source deviation compensator disposed between the reflector and the light source to focus an image of the light source is focused to a focal point of the reflecting surface, and a light path changer to direct at least a portion of a beam with a radiation angle less than an angle of the exit portion toward the reflecting surface.

Abstract: A side light-emitting device, a backlight unit using the side light-emitting device as a light source, and a liquid crystal display (LCD) apparatus employing the backlight unit. The side light-emitting device includes a light-emitting device to generate light and a side emitter disposed adjacent to the light-emitting device to emit the light incident from the light-emitting device in a lateral direction. The side emitter includes a reflecting surface to reflect incident light, and a reflecting/refracting surface to totally internally reflect light incident directly from the light-emitting device to the reflecting surface and to refract the light incident from the reflecting surface so that the refracted light propagates in the lateral direction. Since the side light-emitting device emits most the light in the lateral direction, using the side light-emitting device as a light source in a backlight unit allows light to be mixed evenly.

Abstract: A backlight unit and a liquid crystal display (LCD) apparatus employing the backlight unit. The backlight unit includes a plurality of light-emitting device units disposed on a base plate in an array, each light-emitting device unit including a collimator to collimate light emitted by a light-emitting device so that the light propagates in a principal propagation direction of light emitted from light-emitting device, a plurality of side reflectors disposed in an array above the array of corresponding light-emitting device units and to reflect lateral light incident from the corresponding light-emitting device units, a reflective diffusion plate to reflect and diffuse light incident from the side reflectors, and a transmissive diffusion plate that is disposed above the light-emitting device units, to transmit and diffuse the incident and reflected light.

Abstract: An illumination unit is provided which includes a glass rod including a parabolic reflection surface, a light incident surface facing the parabolic reflection surface, a concave portion formed inwardly in the light incident surface at a position of a focal point of the parabolic reflection surface, and a light guide portion facing the parabolic reflection surface and having a rectangular section. An LED module is disposed at the focal point of the parabolic reflection surface and emitting light to the parabolic reflection surface through the concave portion. A surface of the light guide portion parallel to the light incident surface is stepped from the light incident surface in a direction in which the rectangular section of the light guide portion decreases.

Abstract: A color prism capable of separating incident light into four color beams and synthesizing incident four-color beams, and a projection-type image display apparatus employing the color prism. The color prism includes: first through third triangular prisms each having two boundary surfaces which face the other two triangular prisms, and an outer surface which transmits or reflects incident light according to an incidence angle of the light; and first through third dichroic filters respectively interposed among the first through third triangular prisms and selectively transmits or reflects incident light according to wavelength so as to separate incident light into first through fourth light beams according to wavelength ranges and synthesize incident first through fourth light beams.

Abstract: A projection-type image display apparatus using a light emitting diode light source including a compact optical arrangement. The projection-type image display apparatus includes an illumination optical system including a light emitting diode light source to produce light and emit the light produced in one direction, a uniform light illumination unit disposed along a first optical path to change a propagation direction of the light emitted from the illumination optical system and to emit uniform light, a display device to form an image from the light emitted from the uniform light illumination unit, and a projection optical system disposed along a second optical path to enlarge and project the image formed by the display device onto a screen, wherein the first optical path along which the uniform light illumination unit is disposed and the second optical path along which the projection optical system is disposed are parallel or substantially parallel to each other.

Abstract: An illumination unit includes a plurality of light source units to emit light beams having different wavelengths, and a synthesizing prism to synthesize the light beams emitted from the light source units to proceed on the same path.

Abstract: An illuminating unit with a compact design which is capable of improving collimating characteristics of beams emitted from a plurality of light sources positioned at different locations, and a projection-type image display apparatus employing the illuminating unit. The illuminating unit includes a base, a plurality of light sources that are positioned at different locations on the base to emit beams of different wavelength bands, and at least one color filter with a predetermined curvature to reflect one or more beams of predetermined wavelengths from among the beams emitted by the plurality of light sources such that the reflected one or more beams propagate in a first direction and to pass one or more remaining beams of other wavelength bands. In the illuminating unit, the beams of different wavelength bands emitted by the plurality of light sources are combined to emit a combination of these beams in the first direction.

Abstract: An image display method of improving brightness of an output image in an image display device using a sequential driving method and a plurality of single-color light sources. The image display method includes extracting a white color component from the primary color image signals, calculating a period to display the white color component, converting the primary color image signals into shortened primary color image signals and a white color image signal based on the period to display the white color component, and driving the single-color light sources together during a period to display the white color image signal and sequentially driving the single-color light sources during a period to display the shortened primary color image signals. The brightness of output images is improved by displaying the white color image signal by simultaneously driving the single-color light sources based on a ratio of a lowest gradient to a highest gradient of the primary color signals.

Abstract: A projection display including first through third light source units to radiate first through third light beams having different colors, respectively, a light path combining unit to combine paths of the first through third light beams, an optical modulator to sequentially modulate the first through third light beams according to image information, and a projection lens unit to magnify and project the modulated light beams onto a screen. The light path combining unit includes first and second prisms. The first prism includes first and second incidence surfaces, through which the first and second light beams are incident, respectively, a first emission surface, and a first selective reflection surface to transmit the second light beam toward the first emission surface.

Abstract: A projection display includes first through third light source units to radiate first through third light beams, respectively, having different colors, an X-cube prism to combine paths of the first through third light beams, an optical modulator to sequentially modulate the first through third light beams according to image information, and a projection lens unit to magnify and project the modulated light beams onto a screen. Each of the first through third light source units includes at least one optical module. The optical module includes a collimator having a first reflective surface in a parabolic shape, and a compact light source located in the vicinity of a focal point of the first reflective surface.