| 摘要 |
PROBLEM TO BE SOLVED: To provide a diffusion sheet that enables an observer to observe an easy-to-see picture even when the observer horizontally moves or stands still and a transmission type screen using the same. SOLUTION: The diffusion sheet 100 is constituted by arraying a plurality of unit lens parts 11 formed of nearly trapezoidal columns so that their long-axis directions are parallel to one another and surfaces of long bases 112 of nearly trapezoidal shapes of cut surfaces perpendicular to the long-axis directions of the nearly trapezoidal columns of the unit lens parts 11 are all on one plane on a light incidence surface side and forming light absorption parts 12 which absorb or/and block external light from a light projection surface side in grooves between adjacent unit lens parts 11, and totally reflects light on sides 111 of the unit lens parts 11. Further, the unit lens parts of the diffusion sheet are characterized in that the distance (h) between both the bases (112 and 113) of the nearly trapezoidal shape in the cut surface is 120 to 400% of the length (p) of the long base 112 (h/p=1.20 to 4.00). The transmission type screen uses such a diffusion sheet. COPYRIGHT: (C)2005,JPO&NCIPI
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