| 摘要 |
PURPOSE:To obtain a focusing plate which has the light diffusibility uniform within the surface and is variable in the light diffusibility, i.e., light distribution characteristic by an electric field by packing a liquid crystal material between two sheets of transparent substrates formed with rugged faces on the surfaces thereby forming a liquid crystal cell. CONSTITUTION:The rugged face 7 is formed on the surface of the transparent substrate 3a and the transparent electrode 4a on the face 7 is made rugged as well. The respective molecules of the liquid crystal in the static state faces random directions and therefore the liquid crystal exhibits the random refractive index distribution for incident light. The incident light diffuses as the refractive indices vary with both sides of the diffusion surface-shaped boundary. The liquid crystal is not regularly oriented at the boundary and therefore the orientation of the molecules is disturbed over the entire part of the liquid crystal layer and the liquid crystal layer itself is the diffuser of light. On the other hand, the respective molecules of the liquid crystal are regularly oriented in the electric field direction and exhibit the specified refractive index for the incident light while the electric field is impressed between the electrodes. The refractive index matching arises on both sides of the diffusion surface- shaped boundary and the incident light transmits the liquid crystal layer if the refractive indices are made coincident with the refractive index of the substrates on the diffusion surfaces.
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