| 摘要 |
PURPOSE:To prevent the surface luminance of a prism from being lowered caused by the damage thereof and to make the flaw and the stain of a condensing plate itself inconspicuous by providing the light emitting surface of the condensing plate with a visual field control member controlling a visual field toward the condensing plate to be transparent or opaque. CONSTITUTION:Light emitted from a cathode tube 1 becomes the light condensed in a normal direction by a condensing control plate 8 laminated on a diffusion resin sheet 7 and a liquid crystal display panel 10 is irradiated with it through the visual field control plate 9. Since the light condensed by the triangular prism on the plate 8 is hardly spoiled by the control plate 9, the panel 10 is efficiently irradiated with it. Besides, since the control plate 9 is opaque in an oblique direction with respect to the normal line, so-called from the outside of the visual field, the irregularity, the stain and the flaw of the control plate 8 itself are made inconspicuous and display quality of an illumination device is improved. Moreover, since the control plate 8 is protected by the control plate 9, it is not damaged and stained. |
