LENS SHEET WITH HIGH UNIFORMITY AND LIGHTING PANEL FOR BACK LIGHT

摘要

PROBLEM TO BE SOLVED: To suppress a waving phenomenon due to local thermal expansion and to improve light and darkness of light due to the phenomenon and uniformity by making a cut in an end part of the lens sheet. SOLUTION: The cut for thermal expansion absorption and reduction is cut continuously or discontinuously in the end part of the lens sheet formed of a transparent synthetic resin sheet having a lens function surface as at least one surface. The back light for liquid crystal which has a light source at one end and emits light in plane through a light guide plate has the lens sheet arranged so that the cut is positioned nearby the light source side. This cut is preferably several millimeters inside from the lens sheet end part. When it is provided within the range of a frame for fixing the back light, it is not seen from outside and the outward show is preferably not spoiled. When the depth of the cut is shallow, the effect is small and the cut needs to be >=1/10 as thick as the lens sheet and is preferably <=2/3 as thick as the lens sheet.