POLARIZING ELEMENT, POLARIZED LIGHT SOURCE DEVICE AND LIQUID CRYSTAL DISPLAY DEVICE

摘要

PROBLEM TO BE SOLVED: To obtain a polarized light source device and liquid crystal display device having excellent luminance and visibility by developing a polarizing element capable of obtaining linearly polarized light of a high degree of polarization exceeding 95% via circularly polarized light separating layers and a quarter-wave plate even if the thickness of cholesteric liquid crystal polymer layers is as thin as about 1 to 10 μm. SOLUTION: This polarizing element has the quarter-wave plate 3 via an adhesive layer 2 of n±0.2 in the refractive index to the average refractive index (n) of the cholesteric liquid crystal polymer layers on the circularly polarized light separating layers 1 consisting of one or >=2 layers of the cholesteric liquid crystal polymer layers, in which the liquid crystal polymers on the surface of the cholesteric liquid crystal polymer layer of the quarter-wave plate 3 side are in a non-oriented state at need. The polarized light source device has the polarizing element described above on the light exit side of a light transmission plate which emits the incident light from the flank fro m one of the upper and lower surface. The liquid crystal display device has a liquid crystal cell on the light exist side of the polarized light source device. As a result, the bright liquid crystal display device having the excellent visibility in a diagonal viewing direction is obtd.