Optimized Slit Pattern with Defect Trap for The Patterned Vertical Alignment Liquid Crystal Cell
Wan Seok Kang1), Seung Hee Lee,2) and Gi-Dong Lee,1)
1Department of Electronics Engineering, Dong-A University, Pusan 604-714, Korea
2School of Advanced Materials Engineering, Chonbuk National University, Chonju-si Chonbuk 561-756, Korea
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The patterned vertical alignment (PVA) technology[1], developed by Samsumg Electronics as a practical and wide-viewing mode, is one of the most useful modes for large-sized application. Dynamical behaviors of the liquid crystal director on the slit of the patterned vertical alignment liquid crystal cellare very unstable because there is a strong competition of strain energy of liquid crystal (LC) director around active area and edge of the wing pattern. In the previous paper [2], we applied the defect trap to the edge of the slit pattern in order to remove the generated defect from an active area of the patterned vertical alignment (PVA) LC cell. In this paper we optimized the slit pattern of the PVA LC cell using the defect trap, which can prevent the generation of the defect on the slit. Experimental result verifies the effect of the defect trap on the slit pattern. Figure 1 shows the compared microphotographs of the generated defects on the slit in the active area of the PVA LCD. In the figure, we can confirm that the proposed slit obviously disturbs the generation of the defect on the slit of the PVA LCD. We also calculated the liquid crystal director field with defect as a function of the slit pattern with defect trap, so that we could optimize the slit pattern with defect trap.
(a) (b)
Fig 1. Experimental comparison of the generated defect on the slit :
(a) conventional structure, (b) proposed structure
References
[1]S. S. Kim, SID Int. Symp. Digest Tech. Papers 35, 760 (2004).
[2] G. D. Lee, J. H. Son, Y. H. Choi, J. J. Lju, K. H. Kim, S. H. Lee, Appl. Phys. Lett. 90, 033509 (2007).