| 摘要 |
PROBLEM TO BE SOLVED: To improve deterioration of brightness caused by variation of polarization component due to the aeolotropy of refraction factor of a diffusion sheet and to suppress emergence of unevenness caused by the non-uniform contact of each sheet. SOLUTION: Out of light from a light source 101 incident on a reflection type polarization plate 104 by way of a reflector 102 or the like, only P-polarized light is transmitted through and S-polarized light is used again by being reflected back to a light guide plate. The light is then outputted after being diffused by a diffusion sheet 105 and P-polarized light is modulated by the aeolotropy of refraction factor of the diffusion sheet 105. Because of this, phase difference of a phase plate 106, set after the diffusion sheet, is controlled so that the component of the polarized light modulated by the diffusion sheet is compensated to linear polarized light. Therefore, the light passed through the phase plate 106 becomes P-polarization component again, converged by a prism sheet 107 and comes into an incident side polarization plate 108 whose axis is adapted to P-polarization light. With this configuration, improvement of the incidence efficiency of the light to a liquid crystal panel 109 and high-luminance display is realized. |
