| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical element condensing and collimating incident light from a light source by arranging the layer of phase difference between polarizing elements and suppressing the transmission of the light made incident at a large angle with respect to a normal direction. <P>SOLUTION: In the optical element, there are arranged, with a 1/2 wavelength plate (B) held in-between, a polarizing element (A) that polarizes/separates the incident light to emit it and that is formed of cholesteric liquid crystal (A), and a polarizing element (A') that has a spiral direction reverse to that of the polarizing element (A) and that is formed of the cholesteric liquid crystal. Further, on the polarizing element (A') side, the polarizing element (A) is also arranged with a 1/2 wavelength plate (B) held in-between. In the polarizing elements (A), (A'), the outgoing light to the incident light in the normal direction has a distortion ratio of 0.5 or higher, and the outgoing light with respect to the incident light made incident with an inclination ≥60° from the normal direction has a distortion ratio of 0.2 or lower, and the linearly polarized component of the outgoing light increases as the angle of incidence becomes larger. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
