• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.527-530
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• 2007

Film compensation to suppress a light leakage in the dark state of fringe-field switching (FFS) at off normal direction was performed by optimizing retardation value of discotic (negative A) and TAC films including in-plane switching (IPS). The normal FFS mode shows wide viewing angle characteristics that region of CR 10:1 is over $70^{\circ}$ of polar angle in all directions. The optimized FFS cell exhibits much better performances than other methods do in terms of CR and color uniformity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.312-313
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• 2008

A transflective liquid crystal displays associated with fringe field switching (FFS) mode of new concept is proposed. The device utilizes unique characteristic of the FFS mode in which the rotation angle of LC director is strongly dependent on electrode position in on state. We use the liquid crystal with negative dielectric anisotropy. Also we are look for optimized electrode size and the optimization of pixel electrode width and distance between them, the LC director could rotate about $22.5^{\circ}$ and $45^{\circ}$ depending on electrode positions. Consequently, we get high transmittance and high reflection on the optimized electrode condition. Respectively, a high image quality transflective display with single gap and single gamma characteristics realized.

• Journal of the Optical Society of Korea
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• v.20 no.1
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• pp.156-164
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• 2016

We demonstrated the pretilt angle effect on the viewing angle properties of a single-domain fringe-field switching (FFS) liquid crystal (LC) mode. By performing the Póincare sphere analysis, we investigated, in detail, the origin of the viewing angle asymmetry that exists in the single-domain FFS LC mode both in the field-on and field-off states. Using this analysis, we confirmed that the pretilt angle reduces the viewing angle symmetry in the single-domain FFS LC mode. Finally, we examined the effect of a zero pretilt angle on the viewing angle symmetry by evaluating real single-domain FFS LC cells.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.3
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• pp.305-310
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• 2004

We have studied the optimal phase retardation value of a homogeneously aligned liquid crystal (LC) driven by fringe-field when using the LC with positive dielectric anisotropy. In general, the transmittance of a homogeneous aligned LC cell under crossed polarizer is maximum when a twist angle of LC by in-plane rotation is 45$^{\circ}$ with polarizer and the cell retardation becomes λ/2. However, the device using the LC with positive dielectric anisotropy does not follow this since the degree of rotation of the LC is dependent on electrode position and in addition the LCs tilt up along the fringe-field. At the center of common and pixel electrode, the LC is most twisted around a middle position of a cell whereas at the edge position of pixel electrode, the LC is most twisted near bottom surface of a cell. Consequently, the optimal phase retardation of the device becomes much larger than λ/2 and the transmittance can be described using the combination of the in-plane switching and twisted nematic mode.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.162-162
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• 2009

Optical bounce which occurs by over twist of the liquid crystal (LC) director has a problem of response time in fringe-field switching (FFS) modes. After removing the electric field, effective birefringence ($d{\Delta}n_{eff}$) at the edge of pixel electrode meets the $\lambda/2$ phase instantly, since tilt angle of LC directors at that position suddenly decreases compared to twist angle. In this paper, based on the careful analysis, origin of optical bounce has been explained.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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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.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.320-323
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• 2008

In this paper, electro-optical characteristic of Nematic Liquid crystal (LC) with varying temperature in different LCD modes, namely Fringe Field Switching (FFS), In-plane switching (IPS), and Patterned Vertical Alignment (PVA) modes are investigated and compared. Electro optic me asurements suggest that rate of change of transmission with temperature in FFS mode was lowest and much more thermally stable as compared to IPS and PVA m odes. However the electro-optical characteristic of patterned vertical alignment (PVA) mode was most affected by changing temperature. The measured threshold voltage was found to be much more thermally stable in FFS and IPS modes than that of PVA mode.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.7
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• pp.647-651
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• 2005

We studied the external pressure-stable advanced frnge field switching (FFS) pixel design with 3 slit sructue. In this mode, a patterned pixel slit is partitioned into 3 areas, namely, two edges and a center, where the edge slit angle is larger than the center slit angle. Thus the reverse twist region in the pixel edge is reduced comparing to the conventional FFS mode so that the LC dynamics in this region becomes very stable. And also, when the external pressure is applied to the panel at the high voltage, the disclination lines (DLs) were barely intruded into active area. Therefore, the structure is use for the pen based system such as the tablet personal computer (PC), personal digital asistant (PDA).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.163-163
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• 2009

Viewing angle controllable liquid crystal display (LCD) associated with fringe-field switching (FFS) mode with high image quality is proposed. In the device, one pixel is composed of main and sub pixels, in which adjacent sub pixel is patterned with pixel electrodes direction orthogonal to the adjacent one. In this way, light leakage can be generated in the all viewing angle directions except the normal direction, realizing view angle controllable LCD in both horizontal and vertical directions.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.1266-1269
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• 2004

This study focuses on the color characteristics of FFS (Fringe Field Switching). We use various methods to prove the high performance of color characteristics in the Fringe Field Switching mode. We have described a color performance of 15" XGA product by the viewing angle range using x, y parameters of CIE chromaticity diagram. And so we used the 2 dimensional analyzing to prove the color shift distribution by viewing angle.