• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
• /
• pp.419-422
• /
• 2005

We have studied transflective liquid crystal displays (LCDs) associated with fringe-field switching (FFS) mode to achieve high image quality. In the past, several cell structures were used to fabricate transflective FFS liquid crystal display s. Their structures and characteristics are carefully examined to find their merits and cons. Further, optimization of cell parameters to achieve a single driving circuit is performed.

• 한국전기전자재료학회논문지
• /
• 제20권12호
• /
• pp.1068-1071
• /
• 2007

When a dielectric layer, in-cell retarder (ICR) is formed between electrode and LC layer to get a single gap transflective fringe-field switching (FFS) display, the operating voltage ($V_{op}$) is highly increased due to the thickness of dielectric material. But, we also knew the phenomenon that the increasing rate of Vop is different whether the 1st common electrode was composed of plate type or slit type. In this paper, the common electrode in transmissive part was composed of slit type which had less steepness effect of the Vop and in reflective part was composed of plate type. The rubbing angle of reflective part can be adjusted properly to match the voltage dependent transmittance and reflectance.

• 한국전기전자재료학회논문지
• /
• 제19권2호
• /
• pp.185-188
• /
• 2006

We studied on the reverse twist near the pixel edge depending on the rubbing direction for the fringe field switching (FFS) mode. Liquid crystal (LC) dynamic and the transmittance near the pixel edge, where the various field directions are generated, depend on the initial rubbing direction because the position of reverse twist is decided by the angle between the electric direction and the LC director at a bias voltage. For example, when the rubbing angle is $7^{\circ}$, the reverse twist appears on the bottom position of the right sharp comer of the pixel edge so that the reverse region exists far away from main active region. But, when the rubbing angle is $-7^{\circ}$, the reverse twist appears on the top position of the right sharp comer of the pixel edge, resulting that the region becomes more close to the main active area and the unstable disclination lines (DLs) easily intrude into the active region. Therefore, it is necessary to keep the reverse twist region far from the active region and it is possible by controlling the rubbing direction in the design of a pixel electrode.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
• /
• pp.560-563
• /
• 2007

The light efficiency of fringe-field switching (FFS) mode was found to be dependent on the magnitude of dielectric anisotropy, indicating that the voltagedependent maximal effective cell retardation value in the on state is a function of magnitude of the dielectric anisotropy of the LC.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
• /
• pp.310-311
• /
• 2008

We have studied electro-optical characteristics of fringe-field switching (FFS) mode with high $d{\Delta}n$ according to the electrode position. In this device, the fringe-electric field drives the LCs to rotate so that the dielectric torque is electrode-positional dependent, which results in electrode-position dependency in the LC's rotating angle. We confirmed polarization microscope image and chromaticity diagram at the different electrode position with LC that have high $d{\Delta}n$. Since the FFS mode is influenced by horizontal and vertical electric field, the FFS mode modulates light using both phase retardation and polarization rotation effect, which had already been verified with previous studies. However, from another point of view, tight modulation of FFS mode has been demonstrated by performing experiment and calculated simulation at the high $d{\Delta}n$ LC cell.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
• /
• pp.1386-1389
• /
• 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
• /
• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
• /
• pp.469-470
• /
• 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
• /
• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
• /
• pp.399-400
• /
• 2008

The light efficiency of fringe-field switching (FFS) mode when using a liquid crystal (LC) with positive dielectric anisotropy was found to be dependent on the magnitude of dielectric anisotropy, such that the lower dielectric anisotropy, the higher. We studied out not only light efficiency but also response time according to dependence on the magnitude of dielectric anisotropy. Rising and decay time became fast and slow respectively according to decreasing the magnitude of dielectric anisotropy. This paper investigates electro-optical characteristic of FFS mode using LC with a positive dielectric anisotropy dependent on the magnitude of dielectric anisotropy of the LC.

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

• 인포메이션 디스플레이
• /
• 제5권5호
• /
• pp.4-9
• /
• 2004

최근 비오이 하이디스에서는 무제한의 광시야각과 시야각에 따른 색변화가 최소화된 선명한 색 특성을 갖는 Advanced FFS(Fringe Field Switching) 기술을 개발하였다. 이 기술은 resin 기술적용(평탄화에 의한 고개구율)없이 종래의 FFS 기술에서 액정의 전기 광특성을 최적화하는 새로운 디자인 룰을 찾아내어 실현하였다. 진보된 화소 개념은 전극의 모서리 구조, 전극 간격/폭, 칼라 필터의 블랙 마트릭스(BM)와 전극 간격등의 key parameters들의 최적화에 의해 달성되었고 액정 셀 내의 모서리와 전기장등이 액정을 미세하게 조정할 수 있도록 있게 된 것이다. 이러한 진보된 설계 개념은 모든 FFS 제품에 반영되어 개발되었다. 뿐만 아니라 12.1" XGA 제품에서 투과율이 22% 증가하고 흑백 대비비(Contrast Ratio)는 33% 증가한 600 : 1의 세계 최고 사양을 갖는 제품을 개발하게 되었다. 특히 태블릿과 노트북용 TFT- LCD 모듈에서 단일 도메인(Single Domain) 모드로도 White상태에서 시야각에 따른 색변화가 0.02 이하의 특성을 갖고 180도/180도의 무제한 시야각을 갖고 있다. Advanced FFS 기술의 브랜드 이름과 슬로건으로 'Viewiz'와 'Vision Magic'을 정하여 마케팅 중이며 세계적인 Top Tier 고객에 제품을 판매 중이고, 2004년 3분기에는 태블릿 시장에서 점유율 70%로 1위를 차지하였다.