| 主权项 |
1. An illumination unit comprising:
a first transparent substrate and a second transparent substrate disposed to be separated from and to face each other; a light source configured to emit light to an end surface of the first transparent substrate; and a light modulation layer disposed in a gap between the first transparent substrate and the second transparent substrate and configured to exhibit a scattering property or transparency with respect to light from the light source, depending on magnitude of an electric field, wherein the light modulation layer includes a first region and a second region, the first region having optical anisotropy and relatively high responsivity with respect to the electric field, and the second region having optical anisotropy and relatively low responsivity with respect to the electric field, and the light modulation layer is configured to satisfy following expressions when the light modulation layer exhibits the scattering property:
A>B>C A1/C1<A2/C2 where A is a magnitude of first scattering of light propagating in a first direction perpendicular to a light incident surface, B is a magnitude of second scattering of light propagating in a second direction perpendicular to the first transparent substrate, C is a magnitude of third scattering of light propagating in a third direction parallel to the light incident surface and parallel to a surface of the first transparent substrate, A1 is a magnitude of the first scattering in a third region, C1 is a magnitude of the third scattering in the third region, A2 is a magnitude of the first scattering in a fourth region farther from the light source of the light modulation layer than the third region, and C2 is a magnitude of the third scattering in the fourth region, and wherein a ratio of the second region to the first region in the light modulation layer is lower in the third region than in the fourth region, and the ratio of the second region to the first region in the fourth region is constant. |
