| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical member without change in luminance uniformity on an emission face due to change of relative positions of point light sources and a light guide plate, and that, capable of alleviating luminance unevenness even with an interval between adjacent light sources in a wide state, by making rectilinearity and diffusibility of light compatible. <P>SOLUTION: In the optical member having a ruggedness structure consisting of a plurality of grooves with ridgelines not crossing each other over a portion of or a whole of its surface, a surface profile curve of the ruggedness structure in an orthogonal direction crossing the ridgeline alternately repeats a minimal point and a maximal point, with a first pitch as a distance between adjacent two maximal points in the orthogonal direction of nearly a constant value within a range of 0.5 to 200 μm. A value obtained by dividing a difference between a maximum value and a minimum value on the optical member of heights of the grooves that is a difference between an average value of heights shown by the adjacent two minimal points and a value of height of a maximal point between the adjacent two minimal points by a sum of the maximal value and the minimal value is to be ≥0.05 and ≤1, and a value obtained by dividing a difference of heights between the adjacent two grooves by a sum of a maximum value and a minimal value of heights of the groove parts is to surpass 0.15 in ≤10% of a whole case. <P>COPYRIGHT: (C)2013,JPO&INPIT |
