Research Development for Liquid-Crystal Optical-Wavefront-Control-Devices by using Molecular Orientation Effects

1.利用向列型液晶和在聚酰亚胺(PI)垂直取向层上光刻部分图案化平行取向层的衬底制备了液晶单元，其中液晶分子分别部分平行于衬底和垂直于衬底。测量了平行和垂直取向层边界区域的光学延迟特性，并解释了平行和垂直取向边界区域的液晶取向状态。利用取向处理后的衬底制作了具有多个取向区域的液晶盒，并测量和评估了液晶透镜的性能。研究了液晶层厚度与图案化面积比之间的关系，分析了有效的光学延迟性，并得到了定量的结果。用有限差分方法模拟了LC导向器的分布，估计了LC导向器在边界上的取向构型。建立了获得良好的光学器件折射率分布的设计准则。液晶盒采用具有多个小直径(~1μm)微图案区的玻璃基板，通过改变微图纹密度的有效面积比来控制其光学位相。根据这些结果，我们制作了折射率分布呈阶梯状或渐变状的液晶盒。然后，我们展示了具有偏转特性的新型液晶光学器件，并分析了它们的光学特性。这些器件的特性也可以通过向LC单元施加交流电压来改变。对这些结果进行了检验，并对研究工作进行了总结。

1. We fabricate the liquid crystal (LC) cells by using a nematic LC and the substrates on which photo-lithographically partly patterned parallel alignment layers on the polyimide (PI) perpendicular alignment layer, where LC molecules are partly aligned parallel and perpendicular to the substrate, respectively.2. The optical retardation properties at the boundary region of parallel and perpendicular alignment layers are measured, and the liquid crystal orientation states at the boundary region of parallel and perpendicular orientations can be explained. The LC cells with several sized alignment regions are fabricated by using the alignment-treated substrates, and LC lens properties are measured and evaluated. The relations between the thickness of LC layers and the ratio of the patterned area are studied and effective optical retardations are analyzed, and then the quantitative results are obtained.3. The LC director distribution is simulated by the finite different method and the configurations of the LC director orientations at the boundaries are estimated. Then the design rules to attain the favorable refractive index distribution for optical devices are established.4. The LC cells are prepared using the glass substrates with many micro-patterned areas of small diameter (〜1 μm), and their optical phase can be controlled by changing the effective area ratio of micro-pattern density.5. According to these results, we fabricate the LC cells where the distributions of the refractive indices change stepwise or graded. Then, we demonstrate new LC optical devices with deflection properties, and analyze their optical properties. The properties of these devices can also be varied by applying an ac voltage to the LC cell.6. These results are examined and the research work is summarized.