Development of a software for analyzing thin film flow of liquid crystals for the purpose of high efficiency of liwuid crystal display manufactureing

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Injection process is one of the most important processes for manufacturing liquid crystal displays (LCD). The purpose of this research project is to develop a widely usedsoftware which can predict numerically the injection process. Such the software makes possible to reduce greatly the injection time for LCD with arbitrary size and shape, leading to high productivity and to a decrease in cost.The Leslie Ericksen equation is selected as a constitutive equation for liquid crystalline flow, and the Hele Shaw approximation was made for both the equation of motion and the constitutive equation. Finite difference method was employed to discretize the governing differential equations. Liquid crystals have three kinds of viscosities depending on molecular orientation. We have measured the viscosities by using a rheometer under conditions that molecules were forced to orient to required directions by an external field. Surface tensions of liquid crystals were also measured. Vie did injection experiments and measured the injection time as well as a time series of free surface locations.We used the software to simulate injection of liquid crystals into liquid crystal cells under some typical computation conditions. As a result, the software could predict smooth flow of liquid crystals in the cells, and effects of injection hole size, a cell gap, and injection pressure on the injection time were clarified. It is also found that the injection time for a liquid crystal cell with two injection holes becomes short compared to that for a cell with single but twice area injection hole. However, the predictions did not agree with experiments. This stems from the fact that the cell gap during injection becomes smaller than the initial cell gap because of the pressure difference between in and out of the cell.