| 摘要 |
PURPOSE: To provide an isotropic lens sheet with a properly wide diffusion angle in which a high luminance can be provided, the light diffusion pattern on the reverse surface of a light guide plate can be made invisible, and the attenuation of output light and generation of equal thickness interference fringe by the distance from a light source can be prevented. CONSTITUTION: In a lens sheet having a base sheet 11, a light transmitting diffusing layer 12, and a lens arrangement layer 13, the base sheet 11 has a smooth reverse surface in which the average roughnessΔz1 and average space S1 of irregularities are less than the maximum wavelength of a light source spectrum, the light transmitting diffusing layer 13 is differed in the index of refraction from the lens arrangement layer, and has fine irregular groups in which the average roughnessΔz2 and average space S2 of irregularities are not less than the maximum wavelength of the light source light spectrum on the surface.
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