| 摘要 |
PURPOSE: A direct backlight is provided to keep the thickness thin and obtain high and uniform luminance by using a diffusion element formed with a reverse pyramid type 2D prism part. CONSTITUTION: A direct backlight includes a light source(110) having a fluorescent lamp for emitting light, and reflecting elements(120) mounted at a lower part and both side parts of the light source for emitting light toward an image display device. A diffusion element(130) has a reverse pyramid type 2D prism part(132) and a predetermined light scattering pattern part(134) formed on an opposite surface from the prism part. The light scattering pattern part faces the light source for making the light incident from the light source and the reflecting elements uniform primarily. The light scattering pattern is formed by corrosion or sandblast. A diffusion sheet(140) contacts the diffusion element for improving the light uniformity additionally. The pyramid part is depressed toward the light scattering pattern part. |
