| 摘要 |
PROBLEM TO BE SOLVED: To increase luminance and to prevent ocurrence of an unclear image formed due to parallax by providing a diffusion film with characteristics such as the low rear diffusion, low polarization cancel and no phase difference of light and allowing a polarizing plate to absorbe rear reflection and increase the contrast. SOLUTION: A beam 21 parallel with a polarizing plate light transmission direction out of incident light is passed through a polarizing plate 201 and converted into a circularly polarized light 21a by linear polarization and a transmitted beam 21b is still circularly polarized light by the characteristics of low rear diffusion, low polarization cancel, and no phase difference included in a diffusion film 203. Since the polarization state is not changed when a beam 21d reflected by a reflection layer is passed through the film 203, the circular polarization direction of beams 21e, 21a are mutually reversed. The beam 21e and rear diffusion light 21c are passed through a 1/4 wavelength phase difference film 202 and converted into linearly polarized light 21f, the polarizing direction of the light 21f becomes rectangular to that of the incident light 21, so that the beams 21c, 21e can not be passed through the polarizing plate 201, rear diffusion is almost removed and a contrast value can be sharply improved. |
