ILLUMINATION DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an illumination device which illuminates a wide range along an arbitrary direction uniformly in a state where illumination efficiency is enhanced by reducing light that does not contribute to illumination.SOLUTION: An illumination device 100 includes: a plurality of light source elements 110 each of which is configured by a light emitting diode 111 and a condenser lens 112 for condensing and emitting the light of the light emitting diode 111; and an anisotropic light diffusion sheet 120 arranged on the light emission side of the condenser lens 112. The anisotropic light diffusion sheet 120 has a wave-like irregular pattern 121 extending in one direction and opposing to the condenser lens 112 on one surface. The irregular pattern 121 meanders in a wave-like form along one direction, and a ratio (B/G) of average depth B of the irregular patterns to a most frequent pitch G of the irregular patterns is 0.4-1.0. An irregular pattern forming surface of the anisotropic light diffusion sheet 120 is oppositely disposed to the light source elements 110, and light from the condenser lens 112 enters the irregular pattern forming surface.SELECTED DRAWING: Figure 1