• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.11
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• pp.1650-1655
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• 2012

AC-PDPs have recently achieved good performance and their image quality can sufficiently compete with the LCD TV. However, it is necessary more effort to improve the luminance and luminous efficacy in the PDP technology. The gas mixture ratio plays a very important role in discharge characteristics, but the mechanism of gas discharge is complex and complicated. In this paper, we investigate the mechanism of gas discharge with Ne+Xe miture ratio through zero and two dimensional fluid simulation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.9
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• pp.1579-1583
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• 2008

We proposed the new structure of ac plasma display panel(PDP) to improve the luminous efficacy and driving voltage characteristics. Through two-dimensional numerical simulations, we analyzed the effects of new counter discharge type, which consists of counter sustain electrodes and auxiliary electrodes. Generally, an advantage of AC PDP with the counter sustain electrodes has been known for the driving characteristics of the low voltage. In this work, the new counter structure using the ignition discharge by the auxiliary pulse applied to the address electrode showed the result of the increased luminous efficacy. The short gap discharge between two auxiliary electrodes on the front plate could intensity the long gap discharge between counter electrodes. The reliability of simulation result could be confirmed by the experimental result in the test panel.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.711-712
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• 2009

The fabrication of micro-scale irregular holes by using PMMA (Poly Methyl Methacrylate) beads in the front dielectric layer was proposed to improve luminous efficacy of an ac plasma display panel. Through the firing process of front dielectric layer, bowl shaped holes with a depth of $2.5{\mu}m$, a top diameter of $8-12{\mu}m$, and a bottom diameter of $4-7{\mu}m$ were fabricated. The proposed ac plasma display panel with the irregular micro-scale holes improved the luminous efficacy by 18 % due to the decrease in the minimum sustain voltage.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.173-176
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• 2009

We suggest a new protective layer for PDP consists of SrO and MgO double layer. This double layer structure protects SrO layer from the contamination by $H_2O$ or $CO_2$ in the air and enable SrO to play as the main cathode material. It was confirmed that the high secondary electron emission characteristics of SrO by Xe ion can bring considerable driving voltage reduction and improvement of luminance and luminous efficacy in PDP.

• Proceedings of the KIEE Conference
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• 2007.11a
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• pp.171-172
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• 2007

PDP의 luminous efficacy의 향상을 위해서는 동작가스의 연구가 매우 중요하다. 본 논문에서는 bolsig simulator를 사용하여 여러 비율의 Xe+Kr+Ne 3원가스 시뮬레이션을 통하여 각 가스입자들에 전달되는 이온화에너지, 여기에너지를 조사하였다. 실험에서 short discharge gap과 long discharge gap을 가진 7인치 테스트 패널 2개를 사용하여 가스압력과 Xe+Kr+Ne 혼합비를 변화시켜가며 discharge voltage, luminance, luminous efficacy를 측정하여, 방전특성을 연구하였다.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.20-23
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• 2009

The efficacy improvement issues in a unit discharge cell have been approached from the structural considerations. The tested cell designs include (a) a coplanar type with annular auxiliary electrode buried in barrier ribs, (b) a coplanar type with split auxiliary electrodes also burred in barrier ribs and (c) a coaxial type with a floating electrode stacked on the base electrode. From spatiotemporally resolved optical images of near-IR emission taken by a gated-ICCD camera and relative VUV emission intensity estimated by laser absorption spectroscopy, the differences in the discharge and light emission performances of those three cell types have been compared and discussed.

• Korean Journal of Optics and Photonics
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• v.24 no.2
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• pp.64-70
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• 2013

In this paper, two white light emitting diodes(LEDs) were manufactured by using two kinds of yellow phosphor, YAG:Ce and $(Sr,Ba)_2SiO_4:Eu$, and their spectroscopic properties were compared and analyzed. We found that the asymmetric double sigmoidal function can be applied to both white LEDs to obtain the center wavelength, the half width, and the skewness parameters. According to this analysis, the half width of the emitting spectrum of silicate phosphor was smaller than that of YAG phosphor, indicating smaller color rendering index. However, the silicate phosphor exhibited better color stability depending on the driving current than the YAG phosphor. The current dependence of the luminous efficacy of both white LEDs was investigated, which showed that efficacy decreased monotonically with current. The efficacy of the silicate-based white LED was lower than that of the YAG-based LED by about 10~12 lm/W.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.12
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• pp.23-30
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• 2009

LEDs are increasingly used for many applications including automotive, aviation, display, transportation and special lighting applications. Generally, the RGB multichip LED luminaire applied to signboard, emotional lighting system and display device and the white LED luminaire applied to general lighting system. white LED spectra for general lighting should be designed for high luminous efficacy as well as good color rendering. This paper describes characteristics of LED luminaire white LED and RGB multichip LED. Two type of LED luminaire prototype used experiment physical, electrical and optic test and performance analyzed. RGB multi-chip and phosphor-type white LED luminaire were analyzed by experiment on their color characteristics and luminous efficacy of radiation, distribution curve, and electrical characteristics. Research work is in progress to develop an improved performance for optic and electrical works well for two type of LED luminaires.

• Journal of Electrical Engineering and Technology
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• v.6 no.1
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• pp.123-127
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• 2011

To clarify the relations of optical properties to the main factors responsible for the loss and damage of luminous efficacy, a 20 min turn-on/turn-off test for 2,000 h for a ceramic metal halide lamp is conducted. The corrosion rates of the arc tube wall and electrode are estimated based on thermal stress. Wall blackening is attributed to the tungsten being transported from the hot electrode tips to the relatively cold arc tube wall. Furthermore, the grain boundaries of the arc tube are changed by the degradation. Distortion of the electrode is observed, and the ignition and the driving voltage of the load both increase. Finally, the color rendering index and the color coordinates are changed after the degradation. The luminous flux and the intensity of the luminous distribution are decreased significantly.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.14-18
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• 2005

It is important to select light sources and luminaires in the process of lighting design. Therefore, development of light sources has been constantly grown for a high efficacy and long life. And, the design of luminaires has been developed for the reflection of light mechanism. But it has been not enough to study for the refraction of light mechanism Therefore, the propose of this study is to study for the refraction of light mechanism. In addition, this study is modeling for the luminous intensity distribution of planar prism to use the results of photometric data that is able to obtain various luminous intensity distribution.