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.