OPTICAL SHEET, SURFACE LIGHT SOURCE DEVICE AND LIQUID CRYSTAL DISPLAY DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a selective light scattering sheet functioning as an optical sheet capable of eliminating luminance irregularity when it is viewed from an oblique direction without lowering the front luminance of a backlight device.

SOLUTION: The selective light scattering sheet 6 has a lower surface on which light is made incident and an upper surface from which the light is emitted, and is composed of base material A and material B whose refractive indexes are different from each other. A refractive index boundary 8 between the base material A and the material B satisfies relation H≥3L when it is assumed that projection length in the thickness direction of the sheet 6 is H and a distance between the boundary 8 and the adjacent boundary 8 is L, and the material B has columnar shape or square pillar shape or truncated cone shape. The sheet 6 has structure obtained by embedding a plurality of members of material B in the base material A.

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