• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.585-588
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• 2003

We have studied how rubbing direction affects generation of disclination line in transmissive microdisplay for $90^{\circ}$ twisted nematic (TN) mode with pixel size of $22.2{\mu}m$. The rubbing direction of bottom substrate is changed from $0^{\circ}$ to $-135^{\circ}$ with a decrease step of $45^{\circ}$, and the results show that the generation regions of the disclination line are of a smallest size in $-135^{\circ}$ direction. The results were the same although the pixel size decreased. Consequently, the use of proper rubbing direction of liquid crystal can help overcome the problems of low aperture ratio and low contrast ratio in transmissive-type microdisplays. In addition, the pretilt angle of initial liquid crystal is found to make an important contribution to generation of the disclination line.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 디스플레이 광소자분야
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• pp.153-156
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• 2004

We have studied electro-optic characteristics of transflective liquid crystal display (LCD) using in-plane switching mode. Unlike previous transflective LCD using a dual gap structure and multi driving circuit, this transflective LCD has a single gap structure and a single driving circuit. In the voltage on state, the electric field is applied horizontally to the LC directors, and then homogeneously aligned LC directors at initial state is rotated to with the electric field. But the twist angle of the LC directors in reflective area is lower than transmissive area. As a result, it is possible to design the transflective LCD with a single gap and a single driving circuit. The transflective display associated with this LC cell exhibits a wide viewing angle in both reflective and transmissive areas.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 춘계학술대회 논문집 디스플레이 광소자 분야
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• pp.54-57
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• 2005

We have designed a single gap transflective liquid crystal display (LCD) driven by a fringe electric field, in which the +LC (${\Delta}{\varepsilon}$=7.4, rubbing angle= $80^{\circ}$) is homogeneously aligned in the initial state. This device is a problem that the voltage-dependent transmittance and reflectance curves do not match each other. Thus a dual driving circuit is required. This study shows that optimization of the rubbing angle in the transmissive and reflective regions solves this problem so that the transflective display with a single cell gap and single gamma curve for reflective and transmissive region is possible.

• 한국전기전자재료학회논문지
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• 제16권6호
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• pp.501-509
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• 2003

We have designed transflective liquid crystal display(LCD) associated with in-plane switching of a LC director driven by fringe-field, unlike other LCD mode. Reflective area consists of a λ/2 compensation film and a LC cell with retardation value(dΔn) of λ/4 with their optic axes making an angle of 15$^{\circ}$ and 75$^{\circ}$ against polarizer, respectively. In the transmissive area, top and bottom polarizers are parallel each other, an LC has a dΔn of λ/2, and another λ/2 compensation film is inserted between the LC cell and bottom polarizer. With the configuration, both devices show dark state initially. When an incident light is 550nm, the device shows wide-viewing-angle characteristics such that in the reflective area the contrast ratio target than 5 exists up to 55$^{\circ}$ of polar angle in all directions and in transmissive area it exists about 100$^{\circ}$ in vortical direction and 110$^{\circ}$ in horizontal direction.

• Journal of the Optical Society of Korea
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• 제14권3호
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• pp.260-265
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• 2010

This paper proposes a transflective configuration of the dual operating mode liquid crystal display, which has transmissive dynamic and reflective memory parts in its pixel. By employing a wideband structure and optimizing the cell-gap of the liquid crystal layer, the reflective memory part shows a very low reflectance in the dark state, good dispersion properties for the entire visible range, as well as high reflectance in the bright state. The transmissive dynamic part is designed to have the same cell-gap and rubbing direction as those of the reflective part. The driving voltage of the dynamic part and transmittance of the bright state can also be controlled by using compensation film with a positive a-plate, which can compensate the reflective part. Experimental results in the memory part operation demonstrate that the contrast ratio is over 50:1 and the reflectance in the dark state is reduced to 56% on average of that of the conventional dual mode configuration for the entire visible range. The contrast ratio of the dynamic part is 300:1.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.421-422
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• 2007

The fringe electric field driven transflective liquid crystal display with dual orientation has a problem that the voltage-dependent transmittance and reflectance curves do not match each other, requiring a dual driving circuit to achieve a high electro-optic performance. Optimizations of the electrode structure in the array substrate and rubbing direction solve this problem so that the transflective display with a single gap and a single gamma curve for reflective and transmissive region is possible.

• Journal of Information Display
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• 제10권2호
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• pp.68-71
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• 2009

A replica-molding method of fabricating a dual-gap substrate for transflective liquid crystal (LC) displays is demonstrated. The dual-gap substrate provides homeotropic alignment for the LC molecules without any surface treatment and embedded bilevel microstructure on one of the two surfaces to maintain different cell gaps between the transmissive and reflective subpixels. The proposed transflective LC cell shows no electro-optic disparity between two subpixels and reduces the panel thickness and weight by 30% compared to the conventional transflective LC cell, which has two glass substrates.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.284-287
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• 2008

In this paper, a new Twisted Nematic (TN) transflective liquid crystal display configuration with single cell gap for both transmissive and reflective mode and without sub-pixel separation is proposed. The Transmittance vs. Voltage Curve (TVC) and Reflectance vs. Voltage Curve (RVC) are matched.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.895-898
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• 2004

We propose configurations for a transflective in-plane switching (IPS) cell using muti-domain structures. Usually, the cell configurations for a transflective liquid crystal(LC) cell have a complicated structure, because retardation change of transmissive part and reflective part are not same. The transflective LC cell should have two configurations for each part, such as a multi-cell gap structure. With the ion-beam alignment and the horizontal switching LC cell, a simple structure for a transflective LC cell is proposed. The configuration only adopts one cell gap structure, which may help the enhancement of a yield. Their original optical properties in conventional transmissive and reflective type IPS liquid crystal dispaly(LCD) are kept, it shows the wide-viewing angle and the good wavelength dispersion characteristics.

• Journal of Information Display
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• 제12권1호
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• pp.11-15
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• 2011

An inverse-twisted-nematic (ITN) transflective (TRF) liquid crystal (LC) display, where two imprinted optical films (IOFs) with surface microstructures are embedded was developed. One of the IOFs serves as an in-cell patterned retarder with multioptic axes, and the other behaves as a viewing-angle enhancement film. In the presence of an applied voltage, the surface microstructures on the IOFs provide the spontaneous twist of the LC from a vertically aligned state to a $90^{\circ}$ twisted-nematic (TN) state in the transmissive part, and to a $45^{\circ}$ TN state in the reflective part. The developed ITN TRF LC display exhibits high transmission and reflectance, fast response, and wide-viewing characteristics, along with achromaticity.