Date

Place

Room H (Room Hall 1, 1F)
P1. Poster Session I
August 20, 2015 (Thursday)
14:00 ~ 15:30

[P1-82]
14:00 ~ 15:30
Title:Improvement of Off-Axis Gamma Distortion in Vertical Alignment Liquid Crystal Mode Using Hybrid Pixel Electrode Structure
Jeong Min Bae, Min Kyu Park, Jin-Tae Kim, and Hak-Rin Kim (Kyungpook Nat'l Univ., Korea)
Abstract: In this study, we propose a new VA LC mode with hybrid electrode structures to reduce an off-axis color shift. In our LC mode, the main-region is formed like the micro-patterned vertical alignment (MPVA) mode and the sub-region is composed of the conventional patterned vertical alignment (PVA) mode, where the threshold voltage of the MPVA mode is 2.57V, and the CPVA mode is 2.22V. The difference of threshold voltage between two modes can be explained as the difference in the electric field strength caused by the area ratio of electrode each LC mode. For such a reason, the proposed electrode structure consist of two regions with different electric field leading to different LC director distribution in these two areas. The difference of these LC performance improves reducing color shift defined an off-axis Gamma Distortion Index (GDI) as Reference of MPVA mode has a GDI value of 0.6944 at (��,��)=(60��,0��), and the GDI value of our LC mode is 0.6234 at (��,��)=(60��,0��) viewing direction which is improved to 6.32% over the conventional four-domain MPVA LC mode. Also we designed pixel electrode with no disclination line and without decreasing maximum luminance. The hybrid electrode structure imposes different threshold voltage at two region divided by electrode area with no additional driving circuits and no decrease of contrast ratio. This indicates that a proposed LC mode with multi-domain alignment reduces the color shift at off-axis viewing angle. The GDI value can be further reduced by optimizing the area ratio of MPVA/PVA.
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