| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an optical path switching element, a spatial optical modulator, and an image display device which have simple structures, high durability and light use efficiency, and fast response speeds. <P>SOLUTION: The direction of an applied electric field is controlled to the normal direction and tangential direction of a light incidence part 3 by varying voltages applied to two substrate electrodes 7 and one transparent electrode 10 to change the alignment direction of liquid crystal molecules 12. In Fig. 1 (A), the refractive index n<SB>2</SB>of a variable refractive index substance 5 becomes smaller than the refractive index n<SB>1</SB>of a light guide member and incident light is totally reflected by the interface between the transparent electrode 10 and variable refractive index substance 5 to exit to the right of the optical path switching element. In Fig. 1 (B), n<SB>2</SB>is larger than n<SB>1</SB>and when the angleαbetween the normal of a surface constituting a reflection part 15 and the normal of a surface constituting the light incidence part 3 is set toθ<SB>2</SB>/2, the reflected light exits at right angle to the light incidence part 3. In this constitution, optical switching is performed by optical path switching and a force by an electric field is always applied at this time, thereby realizing high-speed driving. <P>COPYRIGHT: (C)2004,JPO</p> |
