| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical film including a nonglaring layer which controls the direction of light illuminating a display from outside to improve the visibility of characters and images displayed on the display and an image display device using the optical film. SOLUTION: The optical film includes the nonglaring layer having on its surface such an array of projection or recessed upheaval that a value NN found by methods (1) to (4) mentioned below is <=1,000. Namely, (1) the upheaval surface of the optical film is divided longitudinally and laterally into 100×100, i.e., 10,000 parts, (2) standard deviations D in the interval between positions where adjacent projections or recesses have peaks of each divided surface are calculated, and (3) the mean value M of values of the standard deviations D of the respective 10,000 divided surfaces is found to (4) find the number NN of divided surfaces whose standard deviations D are less than 50% of the mean value M. Further, the optical film including the nonglaring layer is characterized in that the ratio that a tilt angle to a regular reflection surface which is measured in aperture 2 square micron order is <=0.5 deg. is <=2%. |
