| 摘要 |
White points (point-like abnormal emission) are made scare even if prismatic projection rows of a prism sheet are pressed against an emission face of a light guide plate. A plurality of prismatic projections are formed side by side on an inner face of a prism sheet. Each prismatic projection row has a steep slope for light input and a gentle slope for inner-reflection, the gentle slope being provided with a plurality of fine projections in a predetermined range near to the tip of the prismatic projection row. Fine projections may be ridge-like or dome-like projections. The tips of prismatic projection rows may be diverge to form a plurality of top portions having cross sections like triangles. Even if LCD panel or the like presses the prism sheet partially hard against the emission face of the light guide plate and causes tip portions of the prismatic projection rows to be subject to yield-deformation, conspicuous white points are avoided from appearing because contacting occur at a plurality of scattered parts.
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