| 摘要 |
PURPOSE: To enhance luminance and to widen a half-power angles by forming projections or grooves of plural shapes varying in the luminance and half-power angles so as to coexist locally. CONSTITUTION: The one surface of a light transmission plate 12 for guiding the light from a light source 11 is defined as a transparent surface 3, the other surface as a reflection plate 14 and the surface on which the light of the light source 11 is made incident as an incident surface 15. The micro-projections 16 having triangular sectional shapes are then formed on the transparent surface 13. These projections 16 are so disposed as to intersect with the light source 11 and are so formed as to intersect with the direction of the liquid crystal display element 19 where liquid crystal pixels are arranged. Further, the projections 16 vary in the heights of the projections 16 in the transverse direction of the light transmission plate. Further, the projections 16 consist of two kinds of the projections; projections A16' and projections B16" varying in the shapes. The projections A16' and projections B16" formed on the transparent surface 13 of the light transmission plate 12 coexist locally and further, the ratios of the respective projections A16', B16" are changed according to distances from the light source 11. Then, the exit characteristics intrinsic to the respective projections A16', B16" are synthesized as well as the exit characteristics from the light transmission plate 12. |
