To provide a backlight unit and a liquid crystal display device in which a polarized light separation function to contribute to realization of low power consumption and high luminance is arranged into a simplified structure so that cost reduction is possible.
The backlight unit 10 has a reflecting type polarized light separation function, in which an outgoing ray Lo is obtained that has an increased ratio of P polarized light component Ep having a polarized light direction in parallel with the light incident face by arranging that a light source 1, collimator lens 2, and a prismatic linear alignment 3 of prismatic surfaces having one flat face and other faces in which a plurality of triangular prismatic unit-prisms aligned with respective edge lines in parallel are arranged in this order with the prismatic surfaces facing the direction of a light-outgoing face or a light incident face. An incident angle to a prism slope of the unit-prism with an isosceles triangle is preferably to have a Brewster angle B, while the vertical angle T of the prism is preferably made two-fold of the complementary angle of B. This backlight unit is used as the light source of a liquid crystal cell 6 including a first polarized light plate 4a, the liquid crystal cell 5, and a first polarized light plate 4b to obtain the liquid crystal display device 20.
| JP2000098132A | 2000-04-07 |
Keiko Fukamachi
Hideo Ito
Hiromi Fujimasu
Naoki Goto
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