LIGHT GUIDE FILM FOR ULTRA-SLIM LIQUID CRYSTAL BACKLIGHT, ULTRA-SLIM LIQUID CRYSTAL BACKLIGHT UNIT, AND PORTABLE COMPUTER

摘要

PROBLEM TO BE SOLVED: To provide a light guide film for an ultra-slim liquid crystal backlight capable of achieving reduction in thickness and suppressing reduction in luminance and its unevenness, and to provide an ultra-slim liquid crystal backlight unit in which luminance unevenness hardly occurs, due to the suppression of reduction in luminance and its unevenness of light rays emitted from the light guide film, and reduction in thickness is achieved, and a portable computer.SOLUTION: A light guide film according to the present invention is a light guide film for an ultra-slim liquid crystal backlight that substantially uniformly emits light rays incident from an edge face from a front face and has the average thickness of 600 m or less. The light guide film has a retardation value (Re) that is 50 nm or less and has an average residual stress that is 8×10Pa or less.