• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1067-1070
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• 2005

A large size flat panel LCD-TV must fulfill different requirements than a desktop LCD-monitor: The contrast must be much larger, the viewing angle should be as wide as possible and the switching times must be shorter to allow moving pictures to be displayed naturally. The "Vertically Aligned" technology is most promising to realize such a product. LC-material development for this technology began at Merck about 10 years ago. New materials based on the 1,1,6,7-tetrafluoroindane skeleton were recently synthesized via ortho-metallation and intramolecular Heck cyclization followed by an oxidative fluorination procedure. The materials offer improved properties over liquid crystals currently employed in flat panel LCD-TVs.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.664-667
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• 2003

Super In Plane Switching (S-IPS) technology is applied for large TFT-LCD panels used in TV applications. It has a lot of advantages in comparison to the alternative, VA technology. S-IPS shows excellent viewing angle properties and fast response time between intermediate gray levels. If the performance parameters which describe the actual visual performance are considered, S-IPS is much more advantageous.$^{1)}$ However, it shows relatively low contrast ratio in diagonal direction compared to viewing angle characteristic in upper/down direction in S-IPS. In order to compensate the relatively low diagonal contrast ratio, a newly designed optical film was applied and the truly wide view angle of a S-IPS TW(True Wide)-IPS) was achieved. Our newly developed 30-inch TFT-LCD panel reveals TW-IPS that is optimized for TV application

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.393-395
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• 2005

Super In Plane Switching (S-IPS) technology is applied for large TFT-LCD panels used in TV applications. It has a lot of advantages in comparison to the alternative, VA technology. S-IPS shows excellent viewing angle properties and fast response time between intermediate gray levels. If the performance parameters which describe the actual visual performance are considered, S-IPS is much more $advantageous.^{1)}$ However, it shows relatively low contrast ratio in diagonal direction compared to viewing angle characteristic in upper/down direction in S-IPS. In order to compensate the relatively low diagonal contrast ratio, Super-IPS applying for optical film developed, but Super-IPS still has the problem of color shift in black $pattern.^{2)}$ So we improved this problem by developing Enhanced Super-IPS.

• 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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• 2000.01a
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• pp.9-10
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• 2000

The wide viewing angle and fast response time characteristics of negative dielectric anisotropy nematic liquid crystal (NLC) using a novel vertical-alignment (VA) - 1/4 ${\pi}$ cell mode on a homeotropic alignment layer were investigated. Good voltage-transmittance curves and low driving voltage using the novel VA - 1/4 ${\pi}$ cell mode without a negative compensation film were obtained. The iso-viewing angle characteristics of NLC using the novel VA - 1/4 ${\pi}$ cell mode without a negative compensation film can be achieved. The fast response time of 24.4 ms in NLC was successfully measured. The iso-viewing angle, fast response time, and low driving voltage characteristics using the novel VA - 1/4 ${\pi}$ cell mode can be achieved.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.600-603
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• 2003

VA-LCDs is widely used for recent LCD productions owing to wide viewing angle characteristics with an unusually high contrast ratio. To apply for VA-LCDs, the novel homeotropic alignment materials were synthesized, which have the liquid crystal molecule as a side chain at aromatic diamine in a polyimide structure. These polyimides generated a high pretilt angle $90^{\circ}C$. In this paper, the synthesis and alignment properties of new homeotropic alignment materials will be discussed..

• Polymer(Korea)
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• v.35 no.4
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• pp.337-341
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• 2011

To expand the viewing angle of vertical alignment liquid crystal display (VA-LCD), a wide-band compensation film has been newly developed. VA-LCD needs a retardation film with improved oblique viewing property. The retardation film for VA-LCD has been fabricated by solvent casting and subsequent drawing triacetylcellulose (TAC) containing optical additives. Here, optical birefringence and wavelength dispersion of the retardation film strongly depend on the chemical structures of optical additives. Utilizing quantum mechanical computation, the polarizing anisotropy of retardation film was calculated with respect to additives. It is also realized that the wavelength dispersion of polarizing anisotropy depends on the type and location of substituent to the selected main isomer. When two propionates are substituted to the meta position of the selected main isomer, the wavelength dispersion of polarizing anisotropy shows the most gentle slop, which is well matched with the experimental results. The most gentle slop of wavelength dispersion means that the viewing angle characteristics of LCD are less influenced according to the wavelength of light source of LCD, and it's possible to make better image quality than the present level.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.05a
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• pp.109-112
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• 2004

최근들어, TFT LCD 업체들의 제품 대형화에 따라서 서서히 제품군이 중, 대형 TV를 중심으로 넓은 광시야각 기술 (FFS, IPS, VA)이 적용되고 있으며 고휘도, 고속응답, 고색순도 등 성능향상을 지속하는 가운데 LCD 백라이트로써 LCD TV에 적용하기 위해서는 무엇보다도 현재 기존 제품군보다 높은 휘도 특성의 개선이 요구되고 있다. TV 대응 LCD Panel 은 Monitor 대응 제품에 비해서 일반적으로 해상도가 낮으므로, 투과율면에서 장점은 있으나, 현재의 백라이트 구조로는 만족할만한 성능을 낼 수 없는 상황이다. 그러므로 고휘도 백라이트를 위해서 직하방식 백라이트에 대한 개발 검토가 활발히 이루어지고 있다. 따라서 본 연구에서는 백라이트에서 6500nits를 목표로 직하형 백라이트의 시뮬레이션을 실시하였으며, 램프간 거리, 리플렉터와 램프간 거리, 램프와 확산판간 거리등에 해한 최적화를 통하여 총두께에 따른 특성분석을 실시하였다. 특히, 램프의 수량에 따른 휘도 시뮬레이션을 통해서 백라이트별 기구치수를 결정할 수 있었다. 본 연구에서의 목적인 6500nits의 휘도는 프리즘시트의 적용을 통하여 달성하였다.

• Journal of Information Display
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• v.9 no.4
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• pp.1-5
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• 2008

This paper investigates the effect of the electrode edge of a patterned vertical alignment (PVA) liquid crystal (LC) device on the viewing angle characteristics. In general, a transmissive LCD applies an LC layer with half-wave retardation for a bright state and with zero retardation for a dark state. The retardation of the LC layer would be distorted in each point, however, when a voltage is applied because of the non-uniform voltage distribution in the electrode edge effect. In this paper, the feasibility of the full effect of the electrode edge on the viewing angle property is considered, and the optical viewing angles of the VA LCD with a uniform half-wave LC layer and the PVA LCD with a practical non-uniform LC layer are compared.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1597-1600
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• 2006

LCD business has grown up changing its strategy and main focus by the order of NBPC, MNT and TV for decades. The presence of PDP drives TV market more demanding. The performance of LCD is required to be improved to struggle against PDP. To strengthen the competitiveness in the market, IPS and VA have evolved in various structures such as H-IPS, AS-IPS, and S-PVA. The introduction of new structures which have multi domains requires the interpretation of disclination area. We developed a new simulation tool based on fast Q-tensor method. It enables us to predict the shape of disclinations and the resulting optical properties. We applied this simulation tool to the development of 26-inch wide monitor having H-IPS mode.