| Summary: | 碩士 === 國立東華大學 === 電機工程學系 === 94 === Liquid crystal (LC) alignment plays an important role for the wide-viewing technology in the flat panel display manufacture. The alignment mechanism is due to the interaction between the LC molecular the polyimide which can be modified by contacting rubbing method. However, this conventional process has particle, poor reputability, and electrostatic damage issues. Recently, some non-contacting alignment technologies have been proposed for the improvements of these issues and to enhance the pre-tilt angle of LC for the wide-viewing consideration, they are plasma beam alignment, photo alignment and ion beam alignment, in which, plasma alignment shows better performances in the life time, pre-tilt angle, and reliability, but with lower anchoring energy. Here, we propose a thermal treatment after plasma alignment to expect LC alignment have higher pre-tilt angle and good anchoring energy.
In this study, we prepare several LC boxes to do Taguchi experimental design L9(34), choose the parameters as time, incident angle, energy, and baking temperature, and measure pre-tilt angle as performance index. The purpose of this study is to find out the optimized conditions of the plasma alignment and try to describe the interaction between polyimide and LC molecular by the post thermal treatment.
We find the best pre-tilt angle is 3.99° with the condition of post thermal treatment. This is maybe due to LC molecular rearrange by thermal energy. By the way, we also find the existence of interaction among parameters based on the Taguchi experiments. Two optimized recipes for the different thermal treatments, one is 40 degree incident angle, 2 minutes thermal processing time, 500eV energy, and 150 degree baking temperature by post packed LC boxes thermal treatment, the other is 40 degree incident angle, 3 minutes thermal processing time, 600eV energy, and 150 degree baking temperature by thermal treatment on polyimide before LC packing. Pre-tilt angle is found strong dependence on high temperature treatment.
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