| 摘要 |
PURPOSE: To improve utilization efficiency of light, and increase luminance, of the illumination panel as a back light that is arranged on the back face side of the liquid crystal panel. CONSTITUTION: The surface of the light guide plate 32 of the illumination panel is made a light-exit face 33 and the back face is made an optical face 35. The optical face 35 has a structure in which a set of optical elements that are provided with a curvature face 35a, a flat face 35b, and a slanted face 35c continuously in order from the light-entrance face side (left side in the figure 3) toward the opposite side is provided continuously in many sets. The flat face 35b is made in parallel with the light-exit face 35. The height H of the slanted face 35c to the flat face 35b within the same set becomes gradually taller from the light-entrance face 34 side toward the opposite side. And the lights that are shown by the arrow A, B and C as a representative are irradiated finally in the direction nearly perpendicular from the light-exit face 33 after reflected by either of the slanted faces 35c. |
