| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical path switching device which allows a liquid crystal material used for a polarization switching element to be widely selected, and which has improved temperature characteristic of optical performance while attaining high speed switching time, by preventing degradation in optical performance, even if a cone angle 2θof the liquid crystal material used for polarization switching element is not 45 degrees. SOLUTION: The optical path switching device 4 is composed of the polarization switching element 20 for switching a polarization direction of incident light, and a polarization separation element 30 for separating crossing polarization directions into paths different from each other. In the optical path switching device, the polarization switching element 20 is a surface stable type ferroelectric liquid crystal (SSFLC) element composed of a pair of flat transparent substrates 21, a transparent electrode film and an alignment film which are provided in the transparent substrate and a ferroelectric liquid crystal layer 24 which is held between the transparent substrates and has two stable alignment states by electric fields of different polarity, and in which the angle (cone angle) 2θmade by two alignment axes of the stable states is not 45 degrees. The liquid crystal layer 24 of the SSFLC element is arranged tilting to an incident light axis which is perpendicular to the polarization separation element 30. COPYRIGHT: (C)2010,JPO&INPIT |
