OPTICAL PATH CONTROLLER, SURFACE LIGHT SOURCE DEVICE, POLARIZED LIGHT SOURCE DEVICE AND LIQUID CRYSTAL DISPLAY DEVICE

摘要

PROBLEM TO BE SOLVED: To form a liquid crystal display device which is capable of preventing the occurrence of moires among pixels when a light transmission plate forming stripe patterns of bright parts and dark parts by its exit light indicating directivity in a perpendicular direction is applied to a liquid crystal cell and has an excellent display grade and to approximate the exit light from the light transmission plate to the perpendicular direction effective to the visual recognition of the liquid crystal display device. SOLUTION: This output path control layer 1 has stripe grooves 11 consisting of gentle slopes 12 of 5 to 35 deg. in the angle of inclination to a plane and acute slopes 13 of >=60 deg. periodically and above all, at a period of 10 to 80 μm. This surface light source device has the optical path control layer on the light exit side of the light transmission plate which emits the incident light from the light source arranged on the flank as stripe patterns of the bright parts and dark parts from one of the front and lower surfaces. As a result, the grooves of the optical path control layer decreases the moires by finely dividing the bright lines based on the light transmission plate and the gentle slopes of the grooves change the optical path in a thickness direction by a wedge plate function with good directivity.