| 摘要 |
PROBLEM TO BE SOLVED: To provide a uniform, thin and large area light transmissive body capable of efficiently emitting primary light made incident upon its inside from an outgoing face and preventing the generation of local unenveness in luminance or uneven luminance on the whole light emitting face. SOLUTION: This light transmissive body 3 is constituted so as to guide light at least from one side end face. In this case, many projecting patterns 3a with an approximately trapezoidal shape in which a projecting top side on a cross section orthogonal to the axis of a linear primary light source 1 has a partially straight part are arranged on the rear face being the opposite side of a light outgoing face 3c like dots, solid lines or broken lines at low density on the part close to the light source 1 and high density on the part far from the light source 1 so that the luminance distribution of outgoing light from the outgoing face 3c is approximately uniform. It is preferable that the pattern 3a has an approximately trapezoidal shape in which two corners corresponding to both ends of the projecting top side on the cross section orthogonal to the axis of the light source 1 are rounded and the surface roughness of a surface constituting the projecting top side of the pattern 3a and the surface roughness of a surface on which the patterns 3a are not formed on the forming face of the patterns 3a are <=0.2μm.
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