POLARIZATION CONVERSION SHEET AND SURFACE LIGHT SOURCE APPARATUS

摘要

PROBLEM TO BE SOLVED: To provide a polarization conversion sheet used in a liquid crystal display apparatus capable of carrying out bright display by improving the efficiency of using light emitted from a surface light source apparatus, while increasing a polarization component in a light beam transmission axis direction 8a of a polarizing plate by controlling a polarization state of light emitted from the surface light source apparatus, and further to provide the surface light source apparatus having the polarization conversion sheet.SOLUTION: The surface light source apparatus has a light guide plate 4 where light from a light source 3 is made incident and the polarization conversion sheet 6 which is made of a birefringence film and converts the polarization state of light emitted from the light guide plate 4 and then is made incident thereon. The polarization conversion sheet 6 raises light intensity of the polarization component in the same direction as the light beam transmission axis direction 8a of the polarizing plate 8 of a liquid crystal display unit 2 as to light emitted from the light guide plate 4.