| 摘要 |
A fluorescent lamp 6 emits illumination light (primary light), which is deflected by means of a light guide plate 4 to be converted into a light flux having an enlarged cross section. A liquid crystal display panel 3 is supplied with the light flux via a prism sheet (light control sheet) 12 . The prism sheet 12 or an alternative light control sheet to be employed is capable of rotating polarization involved by the light toward a direction of light transmission axis of a polarization plate 14 . An effective light input to the liquid crystal display panel 3 is achieved by light transmission through the polarization plate 14 at a high transmission rate. The liquid crystal display panel 3 controls polarization state of the inputted light and, according to the state, causes the light to pass through another polarization plate (analyser) 15 . Emission occurs, under intensity control depending on positions, via the polarization plate (analyzer) 15 , to provide an image. Polarization rotation function for modifying the emission of the light guide plate 4 can be obtained through manufacturing of a mother material of the prism sheet 12 by means of one-axle drawing process or two-axle drawing process. Prism cuts may be formed on a back face 8 or emission face 11 of the light guide plate 4 . A polarization-rotating sheet may be alternatively interposed between a prism sheet provided with no polarization-rotating ability and the polarization plate 14.
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