• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.49-50
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• 2006

We have developed vertical alignment liquid crystal display (VA-LCD), of which the viewing angle can be controlled. The VA-LCD has the function of switching between the wide viewing mode and narrow viewing angle mode using one homogeneous aligned (HA) LC layer and one compensation film with a negative C-plate. The retardation of the HA layer at off axis can be controlled by applying an electric field while keeping the retardation value to be zero at normal direction. Consequently, the device exhibits a viewing mode over $170^{\circ}$ in terms of CR = 10 in wide viewing mode and about $60^{\circ}$ in terms of CR = 2 in narrow viewing angle mode m horizontal direction.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.545-548
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• 2007

This Viewing angle control of fringe-field switching (FFS)-LCD using only one panel has been investigated. Viewing angle switching cell is composed of main- and sub-pixel, in which the former has a role of image expression and the latter has a role of viewing angle switching.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.04a
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• pp.45-46
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• 2006

We have studied the viewing angle control using a twist nematic liquid crystal display (TN-LCDs). These TK-LCDs have the characteristics, of which is not good image quality, for examples low Contrast ratio and gray scale inversion problems at upper and down viewing direction. TN-LCDs have the function of switching between the wide viewing mode and narrow viewing angle mode using two tilted LC layers. Tilt angles of the two LC layers, $14^{\circ}$ and $60^{\circ}$ were required in both wide viewing angle and narrow viewing angle modes, respectively. Consequently, this device is compatible with two image performances of which the wide viewing angle mode and Narrow viewing angle mode.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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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.

• 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.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.173-173
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• 2010

We proposed viewing angle switchable liquid crystal display(LCD) associated with fringe-field switching (FFS) mode with high aperture ratio characteristic. In the device, single pixel is separated into two regions, named as main pixel for displaying images and sub pixel for viewing angle control. In sub pixel region, add the common electrode on the top substrate and the initial alignment of liquid crystal is Hybrid Alignment Nematic (HAN) state. In conclusion, we suggested that the device has high aperture ratio characteristic because the LC directors are rotated in which viewing angle control region are generated fringe electric field.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.32-33
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• 2009

We propose viewing angle switchable liquid crystal display(LCD) associated with fringe-field switching (FFS) mode with high aperture ratio characteristic. This device is composed of R(red), G(green), B(blue), pixel and W(white) pixel in which R,G,B pixel shows image and white pixel for both viewing angle control and image. Conventional viewing angle controllable liquid crystal display has not transmittance because the liquid crystal only tilts up without rotates in viewing angle control region. In this paper, we suggested that the device has high transmittance characteristic because the LC directors are rotated in which viewing angle control region are generated fringe electric field.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.629-632
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• 2009

We have proposed a novel viewing angle controllable display of in-plane switching (IPS) mode with single panel. One pixel of this device is divided to two regions, in which main pixel shows image and sub pixel for viewing angle control. In initial state, the liquid crystal of sub pixel is homogeneous aligned on substrate for wide viewing angle mode. On the other hand, after applying voltage, the liquid crystal of sub pixel tilts up for narrow viewing angle mode. The proposed device has advantage for the function for simple manufacturing process and good viewing angle control with single panel.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.699-702
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• 2006

We have developed twist nematic liquid crystal displays (TN-LCDs), of which the viewing angle can be controlled. The TN-LCDs have the function of switching between the wide viewing mode and narrow viewing angle mode using two tilted LC layers. Tilt angles of the two LC layers, $14^{\circ}$ and $60^{\circ}$ were required in both wide viewing angle and narrow viewing angle modes, respectively. In this way, the viewing angle range in terms of contrast ratio 5:1 can be switched from $120^{\circ}$ to $60^{\circ}$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.3
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• pp.311-318
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• 2004

We have studied electro-optic characteristics as a function of pretilt angle ($\theta$$_{p}$) in the fringe-field switching (FFS) mode using the LC with positive dielectric anisotropy. When $\theta$$_{p}$ is increased from 0$^{\circ}$ to 20$^{\circ}$, a maximum transmittance and an operating voltage are obviously decreased. In the viewing angle characteristics, the cell with low pretilt angle has a wide region for the contrast ratio greater than 5 and has a best luminance uniformity. Therefore, in the FFS device, a low pretilt angle is favored for high transmittance and wide viewing angle.gle.