• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.469-470
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• 2008

We have studied electro-optic characteristics as a function of splay elastic constants ($K_{11}$) in the fringe-field switching (FFS) mode using the LC with positive dielectric anisotropy. When $K_{11}$ is increased from 7.7pN to 11.7pN, a maximum transmittance is slightly increased and rising time become a little bit fast. However, operating voltage and threshold voltage is independent. In opposition to rising time, decay time is not affected by $K_{11}$. We already know that $K_{11}$ affects tilt angle of liquid crystals. Therefore, on the occasion of high $K_{11}$, liquid crystals are mainly affected by twist deformation because the higher $K_{11}$, the less tilt angle. In the FFS device, high $K_{11}$ is favorable to reduce tilt angle in on state and thus improve rising response time.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 춘계학술대회 및 기술 세미나 논문집 디스플레이 광소자
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• pp.53-54
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• 2008

We have studied electro-optic characteristics as a function of passivation thickness$(t_p)$ in the fringe-field swiching (FFS) mode using the LC with positive dielectric anisotropy. When $t_p$ is increased from $0.29{\mu}m$ to $3.0{\mu}m$, a maximum transmittance is slightly increased to $2{\mu}m$. However, operating voltage is continuously increased up to above 11v. We found that the tilt angle is decreased between the edge of pixel electrode and the center of each pixel electrode. In the FFS mode using the liquid crystal with positive dielectric anisotropy, transmittance is affected by the tilt angle. When tilt angle is increased, transmittance become decrease. Therefore, in the FFS device, a low tilt angle is favored for high transmittance. It is demonstrated that the suitable passivation thickness make a tilt angle decreased.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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• pp.439-442
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• 2005

In this paper, we propose a cell structure to improve transmittance and aperture ratio with FFS(Fringe Field Switching) mode. As an exemplary cell, we selected conventional FFS cell with dual domain. Optical transmittance and aperture ratio were calculated with 3DFEM numerical solver, TechWiz LCD. The simulation results revealed that transmission increases by more than 10% while aperture ratio increases by more than 4% when compared to conventional FFS mode.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.1386-1389
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• 2008

Conventional viewing angle switching electrode requires pixel division and additional liquid crystal panel. Hence the conventional viewing angle switching has low aperture ratio and high thickness. In this paper we proposed new viewing angle switching using hybrid aligned nematic mode by fringe-field electrode field (named HAN-FFS) with single liquid crystal panel. The fringe-field switching electrode is located at the bottom, and the additional common electrode is located at the top of the cell to control viewing angle. The proposed device is free from additional liquid crystal panel and pixel division. Consequently, the suggested structure has not only high aperture ratio but also show an excellent potential for viewing angle switching.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.2
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• pp.1054-1057
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• 2003

We have studied $90^{\circ}$ twisted nematic (TN) mode driven by fringe electric field, where two polarizers are parallel each other such that the cell shows a black state before a voltage is applied. According to the studies by computer simulation for a LC with negative dielectric anisotropy, the LC twists perpendicular to the horizontal field direction of fringe electric field and the degree of tilt angle is very low, when a voltage is applied. Therefore, the new device exhibits wide viewing angle characteristic due to in-plane switching and high transmittance since the LC director aligns parallel to the polarizer axis.

• Transactions on Electrical and Electronic Materials
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• 제8권3호
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• pp.135-138
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• 2007

In this study, we investigated the electro-optical (EO) characteristic of fringe-field switching (FFS) mode cell by the two kinds of ultraviolet (UV) alignment method on the organic thin film (polyimide: PI). The suitable organic layers for FFS cell and the aligning capabilities of nematic liquid crystal (NLC) using the in-situ photoalignment method were studied; Disclination is observed after conventional photoalignment method for 1h, and in-situ photoalignment method for 1h. Monodomain alignment of the NLC can be observed via insitu photo alignment method for 2 h and 3 h. It is considered that NLC alignment is due to photo-depolymerization of the polymer with oblique non-polarized UV irradiation on PI surface. An unstable V-T curve of UV-aligned FFS-LCD with conventional photoalignment method can be achieved. However, a stable V-T curve of UV-aligned FFS-LCD with in-situ photoalignment method (1 h), and V-T curve of UV-aligned FFS-LCD with in-situ photo alignment method was much stable comparing with that of other UV-aligned FFSLCD's. As a result, more stable EO performance of UV-aligned FFS-LCD with in-situ photoalignment method for 3h is obtained than that of the other UV-aligned FFS-LCD's.

• Journal of Information Display
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• 제10권4호
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• pp.175-179
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• 2009

As the physical properties of nematic liquid crystals vary with respect to temperature, the performances of liquid crystal displays (LCDs) are highly dependent on temperature. Additionally, it is well known that the electro-optic characteristics of LCDs, such as transmittance and threshold voltage, also rely on the LCD switching modes. The temperature dependence of the electro-optic characteristics of the wide-viewing-angle LCD modes, such as in-plane switching (IPS), multidomain vertical alignment by patterned electrode (PVA), and fringe-field switching (FFS), have been studied, and the results showed that the FFS mode has lower temperature dependence compared to the IPS and PVA modes. Since the liquid crystal (LC) reorients in different ways in each mode, this result is associated with the temperature dependence of LC's bend and twist elastic constants, and also with the position of the main reorientation, either in the middle or on the surface of the LC layer.

• 전기학회논문지P
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• 제62권4호
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• pp.223-226
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• 2013

In this study, we investigated the electro-optical(EO) characteristic of fringe-field switching(FFS) mode cell by the two kinds of ultraviolet(UV) alignment method on the organic thin film(polyimide: PI). The suitable organic layersfor FFS cell and the aligning capabilities of nematic liquid crystal(NLC) using the in-situ photoalignment method were studied Disclination is observed after conventional photoalignment method for 1h, and in-situ photoalignment method for 1h. Monodomain alignment of the NLC can be observed via in-situ photoalignment method for 2h and 3h. It is considered that NLC alignment is due to photo-depolymerization of the polymer with oblique non-polarized UV irradiation on PI surface. An unstable V-T curve of UV-aligned FFS-LCD with conventional photoalignment method can be achieved. However, a stable V-T curve of UV-aligned FFS-LCD with in-situ photoalignment method(1h), and V-T curve of UV-aligned FFS-LCD with in-situphotoalignment method was much stable comparing with that of other UV-aligned FFS-LCD's. As a result, more stable EO performanceof UV-aligned FFS-LCD with in-situphotoalignment method for 3h is obtained than that of the other UV-aligned FFS-LCD's.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.780-783
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• 2006

In this paper, we confirmed the yellowish gravity-mura phenomenon in Fringe-Field Switching (FFS) mode using 2-D simulation. As the cell gap increases, while the LC efficiency of blue wavelength remains almost same, that of red and green wavelength increases continuously. As a result, yellowish phenomenon occurs.

• 한국위성정보통신학회논문지
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• 제10권2호
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• pp.75-79
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• 2015

본 연구에서는 폴리이미드 박막위에서의 수직 및 수평배향에서 혼합액정의 배향 특성에 대해서 연구하였다. 혼합액정은 러빙을 이용하여 배향처리하였으며, 러빙에 사용된 폴리이미드 박막은 알킬기를 Side Chain으로 가진 수직배향용 배향막과 그렇지 배향막으로 나누어서 프리틸트각 특성을 측정하였다. 실험결과 혼합액정을 사용하여 양호한 배향상태를 얻을 수 있었으며, 고온에서의 열 안정성에서도 우수한 특성을 보이는 것을 알 수 있었다. 또한 프리틸트각의 발생 원리를 이해하기 위해서 접촉각 측정을 실시하였으며, 이 둘이 밀접한 상관관계를 갖고 있음을 알 수 있었다