• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.390-392
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• 2005

The digital radiation detectors are used clinically by diagnostic apparatus. However the digital radiation detector are some problem like high operating voltage, light blurring, low conversion efficiency, low fill factor, etc. Thus we propose a new radiation detector that the photoconductor layer and liquid crystal layer are coupled in sandwich structure. X-ray absorption in the photoconductor layer controls the state of the liquid crystal via creation of charge carrier and the light modulation of liquid crystal make image formation. The advantage of the new radiation detector is that high resolution image is acquired and the signal amplification is possible by external visible light source. In this study, we study the optical properties and electrical properties of the new radiation detector to irradiate X-ray. The Mercury Iodide($HgI_2$) was used by photoconductor material, and the aluminum is used by reflective layer. The thickness of Mercury Iodide is about $200{\mu}m$, the operating voltage of the liquid crystal is 1.5~5V. The electrical properties of Mercury Iodide was measured, and the transmission efficiency of liquid crystal was measured by modulation potential.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.293-294
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• 2009

We proposed a novel single gap transflective liquid crystal display (LCD) using liquid crystal with negative dielectric anisotropy. We designed cell structure driven by fringe electric field in the transmissive (T) part and vertical electric field in the reflective (R) part. In the device, high surface pretilt angle of the LC in the R-part is achieved through polymerization of an UV curable reactive mesogen (RM) monomer at surfaces. By optimizing the parameters, a newly developed transflective display has characteristics such as single gap and single gamma curve.

• Korean Journal of Optics and Photonics
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• v.26 no.2
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• pp.110-114
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• 2015

We propose a reflective cholesteric liquid crystal cell with reduced color shift, using dichroic dyes. Color-shifted light is absorbed by dye molecules in the proposed dye-doped cholesteric liquid crystal (DDCLC) cell. We have shown that the color shift can be reduced by increasing the concentration of dye molecules in the proposed DDCLC cell.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1377-1380
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• 2008

A development of low power display is an important problem from a point of reduction in worldwide energy consumption. In this research, we aimed to achieve a high quality and low power paper-like reflective full-color display and investigated the design rules for the light diffusing film, LC-cell structure, front lighting systems based on the diffused light control technology. As a result, we successfully obtained the high quality reflective liquid crystal display with a high reflectivity, a wide color gamut and a high motion picture quality.

• Journal of Information Display
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• v.10 no.1
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• pp.28-32
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• 2009

The correlation between the optical performance of the reflective polarizer, which is a key optical component for the brightness enhancement of the liquid crystal display (LCD), and the configuration of optical sheets was investigated in a direct-lit CCFL (cold-cathode fluorescent lamp) backlight. The optical gain of the reflective polarizer, the polarization state of the light emitted from each film, and the loss factor for the polarization conversion process occurring in the lower part of the backlight were determined using a phenomenological approach for the polarization recycling process. The present study suggests that the correlation between the optical performance of the brightness enhancement films and the backlight configuration should be carefully considered in the optimization of the backlight structure.

• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.112-113
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• 2000

주변의 광원을 이용하는 단일 편광판 반사형 액정 표시장치는 전력 소모의 70%이상을 차지하는 배면조명이 필요 없으므로 가볍고 얇으며, 소비전력이 적고, 큰 반사효율을 얻을 수 있는 장점으로 인해 큰 주목을 받고 있다. 현재 단일 편광판 반사형 액정 표시장치는 reflective TN(RTN)$^{(1)}$ 과 mixed-mode TN(MTN)$^{(2)}$ 과 같은 TN액정 모드를 기본적으로 사용하고 있다. 하지만 TN액정 모드를 사용한 반사형 액정 표시장치는 좁은 시야각과 느린 응답 특성 등의 문제점이 있다. 이러한 문제점들을 해결하기 위해 reflective-optically compensated bend(R-OCB)$^{(3)}$ 및 reflective homeotropic TN mode$^{(4)}$ , 반사형 BTN$^{(5)}$ 등을 이용한 반사형 액정 표시장치 등이 보고된 바 있다. (중략)

• Korean Journal of Optics and Photonics
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• v.11 no.2
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• pp.130-134
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• 2000

In this paper, the configuration of a reflectIve bistable tWIsted nematic (BTN) liquid crystal cell is optmnzed for high contrast and high brightness operation. We searched for the optimum opncal parameters of a reflective BTN cell by calculating its optical performances at 3 wavelengths; red, green, and blue. By studying the effect of each optical parameter on the optical performances, we found that the angle of !he polmlzer IS more important than any other opnea! parmlleters iu the deSIgn of a reflective BTN cell. We fablicated a reflective BTN cell with a wide-band retardation Him, whose measmed contrast ratio is 10.6: 1. .6: 1.

• 한국정보디스플레이학회:학술대회논문집
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• 2000.01a
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• pp.19-20
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• 2000

We have developed the 12.1" SVGA reflective type color TFT-LCD(Thin Film Transistor - Liquid Crystal Display) with the high aperture ratio and well designed reflector for the applications such as mini note PC, Note PC and electronic book. The panel shows the high reflectance(30%) and contrast ratio(20:1) resulted from optimizing the optical films and designing the embossing shaped reflector. By improving the chromacity, the color reproducibility was increased up to 20%. As removing the backlight unit, we reduced the power consumption, thickness and weight of the panel to 0.8W, 2.2mm, and 250gram, respectively. According to the above performances, we have obtained fabrication process for mass production, and furthermore, could have access to fast market launching.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.461-462
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• 2006

A single-gap and single-gamma transflective liquid-crystal (LC) display using patterned vertical alignment (PVA) mode was designed. In the device, a vertical electric field drives a vertically aligned LC to tilt down to optimize polarization efficiency. Electrodes of transmissive and reflective area were patterned $22.5^{\circ}$ and $45^{\circ}$ with respect to the polarizer so that a tilt-down direction of the LC director was $22.5^{\circ}$ and $45^{\circ}$ in the reflective and transmissive regions, respectively. In the device, the cell gap was the same for both regions, and the gamma curve matched each other in both regions because tilt angle of LC director was the same according to the applied voltage. Moreover, the dark state was irrespective of the cell retardation value at normal direction, which was highly important in massive fabrications. The switching principle and electro-optic characteristics of the device are reported herein.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.209-214
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• 2006

Adjustable reflective color gamut RGBW transflective liquid crystal display (ARC RGBW TRLCD) applied simple manufacture process and image processing algorithm to achieve high brightness and good color performance both in transmissive and reflective mode. With appropriate modification higher transmittance but no color distortion happens in transmissive mode. Moreover, base on superior reflectance total brightness and color gamut also can be modified under different ambience. It provides the flexibility not only for any environments but also for variant personal hobbies. It is the best technique used both at indoor and outdoor.