Lighting unit and liquid crystal display device using the lighting unit

#1. Field of the Invention

#The present invention relates to a lighting unit and a liquid crystal display device using the lighting unit, and more particularly relates to a structure of a light guide plate used in the lighting unit.

#2. Description of Related Art

#These and other objects and advantages and further description of the invention will be more apparent to those skilled in the art by reference to the following description of various preferred embodiments, taken in connection with the accompanying drawings, in which:

#FIG. 1 is a perspective view schematically showing a configuration of a LCD device using a lighting unit according to a first embodiment of the present invention;

#FIG. 2 is a vertical cross-sectional view showing the configuration of the LCD device according to the first embodiment of the present invention;

#Hereinafter, descriptions will be provided for specific configurations of the LCD device with reference to FIGS. 1 to 7.

#Descriptions will be provided for a lighting unit and a LCD device using the lighting unit according to the first embodiment of the present invention with reference to FIGS. 1 to 4. As shown in FIGS. 1 and 2, the LCD device according to the embodiment are mainly composed of LED light sources 1 for red (R), green (G) and blue (B) colors, controlling means 7, a LCD panel 2, a light guide plate 4, a reflection plate 5, an optical sheet 6 and a reflector 10. The controlling means 7 controls brightness of each of the LED light sources 1. The reflector 10 makes the light emitted from each of the LED light sources 1 incident on the light guide plate 4. The light guide plate 4 mixes the three colors emitted from the LED light sources 1 and guides mixed light to the LCD panel 2. Reflection patterns 9 are arranged on a surface of the light guide plate 4, the surface being closer to the reflection plate 5. The reflection plate 5 reduces loss of light and increase light transmitted to the LCD panel 2. The reflection plate 5 is made of a metallic plate or the like. The LCD panel 2 is that on which images are displayed. The optical sheet 6 located between the light guide plate 4 and the LCD panel 2 makes uniform the light transmission to the LCD panel 2. The optical sheet 6 is made of a diffusion sheet. In addition, in case of this embodiment, diffusion materials 8 are dispersed inside the light guide plate 4. Optical characteristics of the diffusion materials 8 are different from those of the base material of the light guide plate 4.

#It should be noted that it suffices that the diffusion materials 8 are made of a material whose optical characteristics are different from those of the base material of the light guide plate 4. It is possible that diffusion materials 8 of more than one type, each of which has a refractive index different from that of the base material, be dispersed in the base material. It is also possible to use metallic particles of more than one type, each of which has a reflectance larger than that of the base material, are dispersed in the base material. It is furthermore possible to use the former diffusion materials 8 and the latter diffusion materials 8 made of the metallic particles are dispersed in mixture inside the light guide plate 4.