• 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.

• Journal of the Optical Society of Korea
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• v.18 no.6
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• pp.777-782
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• 2014

This paper proposes an RGB to RGBY color conversion algorithm for liquid crystal display (LCD) using RGW pixel structure with two-field (yellow and blue) sequential driving method. The proposed algorithm preserves the hue and saturation of the original color by maintaining the RGB ratio, and it increases the luminance. The performance of the proposed RGBY conversion algorithm is verified using the MATLAB simulation with 24 images of Kodak lossless true color image suite. The simulation results of average color difference CIEDE2000 (${\delta}E^*_{00}$) and scaling factor are 0.99 and 1.89, respectively. These results indicate that the average brightness is increased 1.89 times compared to LCD using conventional RGB pixel structure, without increasing the power consumption and degrading the image quality.

• Fibers and Polymers
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• v.1 no.1
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• pp.25-31
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• 2000

Poly(3-hexyl thiophene)(P3HT) and poly(3-dodecyl thiophene)(P3DT) were polymerized by oxidative coupling with ferric chloride. The P3HT light-emitting device emitted red light and it could be observable in the ordinary indoor light. The device had the turn-on electric field of about 3$\times$$10^7$ V/m. The maximum electroluminescene (EL) intensity was obtained when the thickness of polymer layer was about 130 nm in IT0/P3HT/Al device. The maximum external quantum yield was 0.002%. The maximum luminance was 21 cd/$m^2$. The EL intensity decreases with increasing the crystallinity of the polymer layer. By using the oriented poly(3-alkyl thiophene)(PAT) layer as an electroluminescent layer in the ITO/polymer/Al light-emitting devices, the polarized EL light emission was observed. The EL intensity ratio of parallel to perpendicular direction to the stretch direction for P3HT was about 1.40.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.143-146
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• 2008

Dynamic range of LCD panel can be dramatically improved by adaptive dimming technique. Adaptive control of LED backlight by input signal can reduce the light leakage of LCD panel and achieve high contrast ratio. An algorithm is proposed to distinguish the input signal and get proper luminance level. For lower cost of LCD panel, white light LED is used to accomplish 2D dimming and get better image performance of LCD.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1056-1058
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• 2005

Electrical and optical characteristics of MEH-PPV-based PLEDs with the LiF anode interfacial layer were investigated. The maximum luminance efficiency of the device with a LiF anode interfacial layer of 1-nm-thick was 3.0 lm/W, which is higher than 1.97 lm/W of the device without a LiF layer. By inserting LiF, excess injected holes from ITO anode can be blocked and hence the recombination ratio of electrons and holes can be increased in the emitting layer to improve device efficiency.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.863-864
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• 2005

In recent years, we use overdriving scheme to improve the response time of the liquid crystal. Since conventional overdriving scheme uses memory to perform ideal processing, it is desired to reduce system cost by decreasing the data stored in these SDRAMs. As a general compression method, quantization, sub-sampling and Block Truncation Coding ( BTC ) are used, which process data in block base and cause block effect. So we proposed new data compression method by color space conversion. Because this method compresses luminance and chrominance signal by different ratio, it can efficiently reduce error of block effect in decompression image.

• Journal of the Korean Institute of Educational Facilities
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• v.9 no.5
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• pp.13-21
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• 2002

Daylighting in educational environment is very important as it has an effect on students' performance as well as in their visual health. It is regarded as a good energy conservation method in saving energy used for lighting. This study conducted initial daylight measurements to analyze luminous environment in classrooms of Korean elementary school. The results indicated that the typical classroom had a reasonable level of daylight. However, it also found that the classroom had some problems of the uniformity of illuminance and the contrast of brightness of surfaces in the classroom. It is argued that daylighting design for school classroom should consider these aspects to make daylit classrooms ideal so as to provide comfortable visual environment.

• Journal of the Korean Solar Energy Society
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• v.24 no.4
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• pp.77-87
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• 2004

BIPV or double skin applied to the surface of the building, power and thermal load cannot both be increased. In the case of BIPV, because it is applied to the facade, incident solar energy decreases and efficiency drops off. The system in this paper complements these disadvantages and aims to decrease the heating & cooling load by transforming solar energy to electronic and thermal energy. The research in this paper is about the applicability of the clear PV attached double-skin system. And the PV electronic generation and the factors that affect the heating & cooling load such as the daily radiation, sun shading ratio, heating & cooling load, daylight luminance and glare distributions in the building are simulated.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.233-233
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• 1999

본 연구에서는 2성분계 gas(Ne+Xe)를 사용하여 기체압력(p), 진동수(f)에 따라 VUV(Vacuum Ultra Violet) spectrum 147, 173nm 파장과 IR(Infrared) spectrum 823nm, 828nm을 Vacuum Monochromator(Acton-VM 507)를 통해 측정하였다. 휘도(Luminance)와 전력(Power)측면에서 Ne+ Xe 최적의 가스 조성비를 찾기 위해서 Xe의 혼합비에 따른 IR영역인 823nm, 828nm을 측정결과, Xe 4%일 때 좋은 효율을 나타냈다. 기체압력이 200Torr에서는 Xe(3P1)에 기인하는 147nm가 주요한 파장이며, 기체압력이 400Torr, 600Torr일때는 Xe(3P2)에 기인하는 173nm 파장이 주요함을 알 수 있었다. 또한 공간 방전 이미지를 전압 pulse 인가후 ICCD Camera(V-Tek)의 Ready time, On Time을 조절하면서 50ns delay로 관측하였다. 향후 실험계획은 실제 상용화되고 있는 혼합가스 He+Ne+Xe의 조성비에 따른 자세한 실험을 할 것이다.

• Proceedings of the IEEK Conference
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• 2000.06e
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• pp.65-68
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• 2000

We design a new driving system of 5" true color FED using current controlled PWM method. Further more, we successfully developed a 5" FED panel, which resolution is 320$\times$240(Color). When we design a 5" FED driving circuit, FED tips are modeled as R-C for circuit simulator of FED driving circuit. In Video data processing, parallel R, G, B input signals is processed independently, so duty ratio increase and no noise, high quality performance is achieved in display of 5" FED. The luminance is about 100cd/$m^2$, the anode power consumption Is 2.1W and total power of the driving system is 21.54W