| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical element capable of condensing light incident from a light source and collimating the light, and also, capable of suppressing the light in an optional direction from being transmitted. <P>SOLUTION: Regarding the polarizing element (A) for polarizing/separating the incident light, and emitting the light, and formed of cholesteric crystal liquid, the distortion ratio of the exit light after being made incident on the element in a normal direction is ≥0.5, and the distortion ratio of the exit light after being made incident on the element with an inclination of ≥60° from a normal direction is ≤0.2, and as the incident angle becomes larger, the linear polarization components of the exit light are more increased, and the optical element is constituted as follows; the polarizing element (A), a 1/2 wavelength plate (B), a layer (C) whose front phase difference (normal direction) is nearly zero, and generating a phase difference with reference to the incident light inclined in the normal direction, and a 1/4 wavelength plate (D) are arranged in this order, besides, a linearly polarized light reflection type polarizer (E) for transmitting one of linearly polarized light beams crossing each other and selectively reflecting the other is arranged on the 1/4 wavelength plate (D) so that the direction of the transmission axis of the polarizer (E) may be in the same direction as that of the axis of the transmitted light transmitted from the polarizing element (A) to the 1/4 wavelength plate (D) in this order. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
