Nowadays, the common method to make an alignment layer of liquid crystal display is rubbing Polyimide (P.I.) thin film, Unfortunately, the rubbing method will reduce the yield of LCDs because of the particles, electrons, etc. created during rubbing on the surface of PI film. therefore many effort have been made to develop the non-contacting method such as photo alignment, plasma alignment, etc. This research focus on the non-contacting method, we hope it will reduce many pollution compared to rubbing alignment. Comparing with PI, polydimethylsiloxane (PDMS) possess higher transparency, batter stability in thermal and chemical, and lower surface free energy about 19 mJ/m^2. Due to the low surface free energy, PDMS can be used as a vertical alignment layer without any surface treatment. Methyl Red (MR) PDMS mixed with PDMS will be used as an alignment layer in this experiment. And the rod-like azo-dye will change its molecular to rotate because the absorption of linear polarized light. By changing the s MR to rotate, we can obtain a micro groove structure on PDMS surface and control the direction of liquid crystals further. Xenon lamp(100nm-1200nm) and the ultraviolet ray lamp (300-500nm) were used in this experiment for thin film. Samples were exposure with different incident angle and intensity of light, respectively, and discussed with different temperature as a factor. According to atomic force microscope ( AFM ) result, we can obtain a PDMS surface with micro groove structure by using Xe lamp and ultraviolet ray, and we can observe the changing tilt angle of liquid crystals by polarized optical microscope (POM).

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