| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a backlight unit capable of enhancing the utilization efficiency of light from a light source, controlling a field of view, and illuminating brightly. <P>SOLUTION: The backlight unit 10 has the light source 1, a light guide plate 2, and an illumination light extraction member 7. The light guide plate 2 has a light guide passage 8 guiding the light emitted from the light source 1 and a diffraction grating 6 arranged on the light guide passage 8 diffracting the light H guided by the light guide passage 8, and emitting it toward outside the light guide passage 8 through a light emission face 9. The illumination light extraction member 7 takes out only a light component having an emission angle within a prescribed angle to the light emission face 9 out of the light emitted from the light guide plate 2, and returns the light component excluding a taken-out light component to the light guide plate 2 side. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
