Abstract: A backlight unit including at least one light source that emits light, a light guide panel guiding light that is incident to a side surface thereof, a light incident portion, which protrudes to be inclined with respect to the side surface of the light guide panel, and which has third and fourth light incident surfaces on which light is incident, and first and second guide members which are arranged to face the third and fourth light incident surfaces, respectively, and which guide the light that is emitted from the light source to be incident on each of the third and fourth light incident surfaces, wherein an air gap is formed between each of the third and fourth light incident surfaces and each of the first and second guide members.

Abstract: A backlight unit includes a point light source emitting light and a light guide panel including a holographic pattern formed to have a concentric circle shape having a center at the point light center. Thus, since the incident azimuth angle of light incident on the holographic pattern can be made constant, an efficiency of light exhausted through the light exhaust surface can be improved. Also, since the distribution of the exhaust azimuth angle of the exhaust light can be made uniform, a uniform brightness can be obtained from the exhaust surface.

Abstract: A backlight unit includes a light guide panel where a holographic pattern is formed. A point light source emits light to an edge of the light guide panel. A refractive member is provided between the point light source and the light guide panel and reduces an azimuth angle of light incident on the light guide panel. The refractive member includes, from an optical axis of the point light source, a light transmission zone transmitting light as it is, a blaze zone where a blaze pattern having a saw-toothed shape in which one surface near the optical axis and substantially parallel to the optical axis is formed, and a prism zone where a triangular prism pattern is formed. The backlight unit may further include a diffusive member diffusing light emitted from the point light source to be incident on the refractive member.

Abstract: An illumination apparatus for planar display devices, including an optical element for making light travel parallel to an optical axis, is provided. The illumination apparatus includes a dot light source for radiating light, and a light guide plate having the optical element. The optical element is composed of a first refraction facet, which is adjacent to the dot light source and increases the emission angle of the light, and a second refraction facet, which is isolated a predetermined distance from the first refraction facet while facing the first refraction facet and reduces the emission angle of the light. In this structure, the light travels parallel to the optical axis. In the illumination apparatus, the emission angle of incident light is reduced, preferably, the light travels parallel to the optical axis.

Abstract: A luminous backlight unit designed to compensate for a difference in distribution of light output on an output surface of a light guiding panel, and a method of manufacturing a diffuser employed in the backlight unit. The backlight unit includes: one or more light sources that emit light; a light guide panel which guides the propagation of light incident through a side edge thereof and has a light-emission surface; a holographic pattern provided on a surface of the light guide panel, for converting the incident light into a surface light and outputting the converted surface light to the light-emission surface; and a diffuser disposed facing the light-emission surface, for diffusing the emitted light from the light-emission surface and is characterized in that distribution of diffusion angles is varied as it goes from a point close to the light source to a point distant from the light source.

Abstract: An edge-light type backlight system including a light guide panel which includes a light incident surface, a light emitting surface, and an optical deflector. The optical deflector is disposed on at least one of the light emitting surface of the light guide panel and a surface opposite to the light emitting surface. The optical deflector includes a first surface and a second surface on opposite sides of a normal line orthogonal to the light incident surface and become farther apart as distance from the light incident surface increases, the first surface and the second surface being perpendicular to the light emitting surface.

Abstract: The backlight for a flat display device including a light source, a light guide plate and a surface hologram is provided. The light guide plate is installed at one side of the light source, and light from the light source travels in the light guide plate while being totally reflected. The surface hologram is formed on at least one surface of the light guide plate. The surface hologram has a pattern of a predetermined grating interval and a predetermined grating depth in order to diffract light at a predetermined angle toward the light guide plate.

Abstract: An edge-light type backlight system including a point light source, a light guide panel including a light incident part into which light enters from the point light source and a light emitting surface from which light is emitted, and an optical path-changing unit which changes a propagation path of light traveling inside the light guide panel. The light incident part includes a light incident surface on which a prism pattern is formed, the light incident surface facing the point light source, and first and second surfaces extending from the light incident surface in a direction in which light travels inside the light guide panel and adapted to reflect light passing through the light incident surface to reduce a direction angle, the first and second surfaces being opposite to each other with respect to an optical axis.

Abstract: A backlight unit is provided including a light guide panel (LGP), a point light source emitting light at an edge of the LGP; and a refraction member being positioned between the point light source and the LGP and refracting the light emitted from the point light source toward the optical axis of the point light source in order to reduce the azimuth angle of the light that is incident upon the LGP. The refraction member includes a prism array in which a V-shaped prism pattern is repeatedly arrayed, the apex of the prism pattern facing the edge of the LGP, and a transparent portion that prevents the light from being totally reflected by the prism pattern in a region along an optical axis of the light source.

Abstract: A liquid crystal display device for displaying an image by changing orientation of a liquid crystal layer sealed between two substrates includes a lower substrate having a microstructure which outputs light incident on a side surface of the lower substrate to an upper surface of the lower substrate, a light source emitting light to the side surface of the lower substrate, a selective reflection panel provided on the upper surface of the lower substrate to reflect light having a predetermined incident angle or more and transmit the remaining light, and a reflection panel provided under the lower substrate.

Abstract: A backlight unit includes a point light source emitting light and a light guide panel including a holographic pattern formed to have a concentric circle shape having a center at the point light center. Thus, since the incident azimuth angle of light incident on the holographic pattern can be made constant, an efficiency of light exhausted through the light exhaust surface can be improved. Also, since the distribution of the exhaust azimuth angle of the exhaust light can be made uniform, a uniform brightness can be obtained from the exhaust surface.

Abstract: A backlight unit includes a light guide panel where a holographic pattern is formed. A point light source emits light to an edge of the light guide panel. A refractive member is provided between the point light source and the light guide panel and reduces an azimuth angle of light incident on the light guide panel. The refractive member includes, from an optical axis of the point light source, a light transmission zone transmitting light as it is, a blaze zone where a blaze pattern having a saw-toothed shape in which one surface near the optical axis and substantially parallel to the optical axis is formed, and a prism zone where a triangular prism pattern is formed. The backlight unit may further include a diffusive member diffusing light emitted from the point light source to be incident on the refractive member.

Abstract: An illumination apparatus for planar display devices, including an optical element for making light travel parallel to an optical axis, is provided. The illumination apparatus includes a dot light source for radiating light, and a light guide plate having the optical element. The optical element is composed of a first refraction facet, which is adjacent to the dot light source and increases the emission angle of the light, and a second refraction facet, which is isolated a predetermined distance from the first refraction facet while facing the first refraction facet and reduces the emission angle of the light. In this structure, the light travels parallel to the optical axis In the illumination apparatus, the emission angle of incident light is reduced, preferably, the light travels parallel to the optical axis.

Abstract: An optical scanning unit with a rotatable hologram disc, including a light source, a rotatable hologram disc provided with a plurality of holograms, the holograms being formed concentrically along a radial direction to diffract a beam emitted from the light source by multiple steps, a reflecting member that reflects the beam emitted from the light source and diffracted by one of the holograms into another hologram, and a fixed hologram correcting the diffracted beam incident through the rotatable hologram disc to focus it on a scanning object. In the optical scanning unit, the light passes through the plurality of holograms formed along a radial direction of the rotatable hologram disc so that a scan width can be extended without reducing a scan speed of the optical scanning unit.

Abstract: A hologram scanner is constructed with a driving source for providing a rotational force, a deflection disk installed at the rotation shaft of the driving source for forming a scanning line, the deflection disk having a plurality of sectors where a hologram pattern for diffracting and deflecting incident light is formed, a TE polarized light emitting device, arranged to face one side of the deflection disk, for emitting TE polarized light so that major axis of an elliptical spot formed at a predetermined position on the deflection disk by the incident light is perpendicular to the radius vector of the deflection disk passing through the spot having an elliptical cross-section and a TE polarization mode, and an optical path altering device for altering the proceeding path of incident light, so that a scanning line formed by the rotation of the deflection disk proceeds to a photoreceptor medium.

Abstract: A stereoscopic display device for compositing and reproducing a plurality of images on a three-dimensional space. The stereoscopic display device includes one or more image sources, a beam splitter, and a holographic optical element, wherein the beam splitter and the holographic optical element are configured to project an image from each image source onto a different space.

Abstract: An optical scanning apparatus which is improved in color registration by reducing bow of a scan line which is formed on a photosensitive medium. A plate having a slit with a width appropriate for a spot size of a scan line and a length corresponding to a predetermined scanning length is interposed between the photosensitive medium and a spot forming apparatus. A light source emits a laser beam, a rotary polygonal mirror reflects light from the light source while being rotated, f-&thgr; lenses cause the light reflected from the rotary polygonal mirror to form a proper spot, and a reflecting mirror disposed on an optical path between the f-&thgr; lenses and the photosensitive medium directs the spot toward the photosensitive medium. The slit plate passes a portion of the spot to uniformly form the scan line.

Abstract: An optical scanning unit with a rotatable hologram disc, including a light source, a rotatable hologram disc provided with a plurality of holograms, the holograms being formed concentrically along a radial direction to diffract a beam emitted from the light source by multiple steps, a reflecting member that reflects the beam emitted from the light source and diffracted by one of the holograms into another hologram, and a fixed hologram correcting the diffracted beam incident through the rotatable hologram disc to focus it on a scanning object. In the optical scanning unit, the light passes through the plurality of holograms formed along a radial direction of the rotatable hologram disc so that a scan width can be extended without reducing a scan speed of the optical scanning unit.

Abstract: A beam scanning system including: a light source; a deflection disc rotatably installed over the light sources and having a hologram pattern on each of the upper and lower surfaces thereof, for diffracting beams emitted from the light source; and a plurality of mirrors for reflecting beams that have been diffracted by the deflection disc, to change the diffracted paths of the beams. Each of the upper and lower hologram patterns is formed with a low density relative to a one-sided hologram pattern.

Abstract: A diffractive deflection beam scanning system including: a plurality of light sources; a deflection disc rotatably mounted over the light sources, having patterns capable of diffracting and deflecting beams emitted from the light sources; a plurality of first reflecting mirrors for changing the traveling paths of beams diffracted and deflected by the deflection disc; a plurality of second reflecting mirrors for reflecting the beams reflected by the first reflecting mirrors in a beam scan direction, wherein the light sources are disposed in a straight line along a bisecting line of the deflection disc, perpendicular to the beam scan direction, and the second reflecting mirrors are arranged over the center of the deflection disc at different heights.