| 摘要 |
PROBLEM TO BE SOLVED: To surely perform alignment of an optical sheet in a planar lighting device without forming a tab in the optical sheet.SOLUTION: An optical sheet whose laminated steps counted from a light emitting surface 12a of a light guide plate 12 are upper steps among a plurality of optical sheets 18 is so formed that the positions of edge parts 181a, 182a, and 183a at an incident surface 12c side of the light guide plate 12 are more separated from the incident surface 12c of the light guide plate 12. In a manner of viewing the light emitting surface 12a of the light guide plate 12 in a plan view, the edge parts 181a, 182a, and 183a of each of the optical sheets 18, at the incident surface 12c side of the light guide plate 12 are exposed without being covered with the optical sheets aligned in each of the upper steps. A light shielding member 20 extends from the incident surface 12c side of the light guide plate 12 to the exposed edge parts 181a, 182a, and 183a of each of the optical sheets 18 so as to fasten the vicinity of each of the edge parts 181a, 182a, and 183a of all the optical sheets 181, 182 and 183 by the light shielding member 20.SELECTED DRAWING: Figure 1 |
