Samsung Electronics Co., Ltd.

Su-mi Lee

Jin-seung Choi

Jee-hong Min

Hwan-young Choi

Moon-gyu Lee

Jin-hwan Kim

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.

Backlight unit

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.

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.

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. Therefore, areas not reached by light, between adjacent dot light sources, are eliminated, and light is uniformly incident upon a hologram so that the luminance and intensity of light emitted from the light guide plate are uniformly distributed.

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Suwon, South Korea

Su-mi Lee