| 摘要 |
PROBLEM TO BE SOLVED: To reduce the difference in brightness of a lamp image of a light source generated in a screen of a display device using a direct backlight unit. SOLUTION: A lens group comprising a plurality of convex unit lenses 11 is formed on at least one surface of a substrate 12 of an optical sheet and is constituted by arranging the plurality of convex unit lenses 11 so that their lengthwise directions are parallel. As for each unit lens, a contour of a cross-section obtained by cutting the unit lens 11 with a plane orthogonal to the lengthwise direction of the convex shape comprises at least 5 inflection points where inclination or curvature is changed, and at least 6 straight lines or curved lines between the inflection points. COPYRIGHT: (C)2010,JPO&INPIT |
