Date

Place

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

[P1-87]
14:00 ~ 15:30
Title:The Study of Order Parameter in PS-VA Mode
Nakcho Choi, Minjung Oh, Yeogeon Yoon, and Namseok Roh (Samsung Display Co., Ltd., Korea)
Abstract: The polymer stablized vetical alignment mode (PS-VA) is the typical liquid crystal mode in TV products.[1,2] The PS-VA mode is the technology to align liquid crystals with reactive megens by the UV exposure process. Aftet the process, liquid crystals have a pretilt angle about 85~89 degrees.The factor to control the pretilt angle is UV exposure dose and appling voltage. When liquid crystals have the pretilt angle, the response time is faster and the transmitance is improved but the Contrast ratio(White luminace/Black luminace) is reduced. The pretilt angle is the polar angle but the azimuthal angle is also important. In the PS-VA mode, when all liquid crystals are aligned to the direction of the micro slit electrod in the white state, the transmittance is the highest. So we investigated the degree of orientation of liquid crystals in the white state in various pretilt conditions. We defined SOI as SVA order parameter in the equation (1). Then we found that there was a relastion between the pretilt angle and the degree of oritentation as shown Fig.1. We could meausure the direction of liquid crystals in the sub micrometer area with Axostep machine and draw the degree of order parameter as shown in Fig.2. When the SOI was not higher over 0.8, liquid crystals were not aligned uniformely. This SOI would be useful tool to develop the PS-VA panel.
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