• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.12a
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• pp.35-38
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• 2006

As a display becomes large recently, Acquisition of high luminance and Luminance uniformity is becoming difficult in the existing CCFL or EEFL backlight system. So, study for a performance enhancement has enforced. but lamp development of flat type is asked for high luminance and a luminance uniformity security in of LCD and area anger trend ultimately. In this paper, we changed a tip shape of an electrode for production by the most suitable LCD backlight surface light source, and confirmed discharge characteristic along discharge gas pressure and voltage, and confirmed electric field distribution and discharge energy characteristic through a Maxwell 2D simulation. Therefore the discharge firing voltage characteristic showed a low characteristic than a rectangular type and round type in case of electrode which used tip of a triangle type, and displayed a discharge electric current as a same voltage was low.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.1058-1061
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• 2004

Recently, According to companies of TFT LCD are making large sized products more and more. In the vortex of Products with a monitor and LCD TV is applied in a technique of a high viewing angle(FFS, IPS, VA). Also, as a high luminance, high speed response time, high degree of a color purity, and so on are continuing to develop a high performance, it is necessary to improve a specific character of high luminance that apply to LCD TV as a LCD BLU. Because a LCD panel for TV usually has a lower resolution that compare to a monitor, the structure of present backlight system can't put out its power even though it has a merit in transmission. Therefore, the examination of improvement about the high luminance direct typed BLU for LCD TV that presupposes several uses of CCFL(Cold Cathode Fluorescent Lamp) or EEFL(External Electrode Fluorescent Lamp)is actively being progressed. Although it is necessary to increase the number of lamps for applying high performance by the direct type, in this case, because we can design the character of luminance for adoption of high performance. We can satisfy with a level of luminance for LCD TV. Accordingly, we analyzed a change of the number of CCFL, mechanical and optical character to produce the direct typed backlight in 32inches spec. Consequently, we achieved luminance of 6597nit,which was including polarization film, and secured the standard for LCD TV.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.05a
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• pp.141-144
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• 2007

BLUs are major component in LCD industry which occupies 90% or more of FPD market worldwide and BLU market is expected to be expanded continuously according to the trend of miniaturization, slimness, low power consumption and low weight. The larger the BLU market scale, the more important standardization of performance evaluation techniques to clearly prescribe the product specification. Currently the government is promoting the establishment of related laws and coincidence with international standards to cope with agreements such as WTO/TBT, but the nongovernmental standardization activities are not enough to be actualized. Furthermore, BLU related components such as CCFL, EEFL, inverter and reflector are already developed for localization to substitute imports with home products but collective standardization, national standardization, and international standardization are still not done. So, performance specifications and evaluation methods for normal fluorescent lamps or industrial lamps are being adopted and used as national standards and safety certification standards instead. Making these standards enables to prepare a chance to penetrate into global market and to promote world best products. Also, by making this collective standard, it provides chances to take part in international standardization activities, to protect domestic industries and technologies, to obtain the trend of advanced technologies, and to be predominant over other countries. That is to say, CCFL standardization helps raise 21st century national strategic technology policy and go ahead of globalization of core technologies.

• Journal of the Korean Vacuum Society
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• v.15 no.3
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• pp.266-272
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• 2006

Application of power higher than the optimum operation value to an external electrode fluorescent lamps(EEFL) leads to the formation of small holes, called pinholes, which subsequently leads to lamp failure. The pinholes come from the insulating breakdown of the capacitor which is the dielectric layer between an external electrode and glass tube. The power of insulation breakdown is proportional to the electric power applied to the lamp. When a lamp current is low in the glass tube of dielectric constant K, the dielectric field strength of pinholes is about 3K kV/mm. The field strength of insulation breakdown decreases as the lamp current increases.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.878-881
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• 2006

In this paper, the luminance and resistance from different electrode materials of external electrode fluorescent lamp are measured and analyzed. New materials and process technology of external electrode are very important for the developed characteristics in lamp fabrication. In this experiments, three different types for the forming of external electrode are Cu and Al taping, silver paste, Ni and Cu electrode-less plating methods. In the measurements of luminance, the results of brightness by Ni and Au plating methods for the external electrode on lamp glass are presented and also compared with the results by the methods using different electrode materials. The measured resistance values of Ni and Au plating process showed a little bit higher than that of silver paste process in spite of developed results of brightness. But the Ni and Ni/Au plating processes are demonstrated best results and are also showed a little bit different brightness due to different previous sulfate etching treatments.

• Journal of the Korean Vacuum Society
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• v.16 no.6
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• pp.424-432
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• 2007

Luminance properties of external electrode fluorescent lamps and optical components in backlight unit (BLU) and optical transmission rates of optical sheets, are investigated for LCD-TV of 32" in diagonal with WXGA level resolution (1366$\times$768). The luminance is measured in 12-lamps and 18-lamps of BLU. The luminance uniformity preserves about 85 % in the 12-lamps backlight, while the luminance of optical components and the efficiency of backlight in the 12-lamps are lower than those in the 18-lamps backlight. When the lamp luminance in BLU having 12-lamps and 18-lamps is normalized as 100 %, the relative luminance of a diffusion plate, a diffusion sheet, a prism sheet (BEF), a polarization sheet (DBEF), has a constant value without dependence on a lamp luminance. The relative luminance of optical components in 12-lamps BLU is lower than that in 18-lamps backlight. The light transmission rate, the relative luminance of liquid crystal display panel with the luminance 100 % of backlight, is 7.14 % in the use of DBEF and BEF, 6.12 % in the use of only DBEF, and 3.21 % in the use of only BEF. Those Data obtained in this experiment for the lamps and optical components, are the design parameters for the LCD backlight.

• Journal of the Korean Vacuum Society
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• v.19 no.1
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• pp.36-44
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• 2010

The ambipolar diffusion equation has been solved in a fine-tube lamp of a few mm in diameter. In the diffusion of radial direction, the plasma diffuses and vanishes away at the glass wall by recombination with the characteristic time of plasma loss is given by $\tau_r\;=\;(r_0/2.4)^2/D_a$. With the radius $r_0{\sim}1\;mm$ and the ambipolar diffusion coefficient $D_a{\sim}0.01\;m^2/s$, the vanishing time is calculated $\tau_r{\sim}10\;{\mu}s$ which corresponds to the least value of frequency 30 kHz for the sustaining the plasma in the operation of high voltage AC-power. In the diffusion of longitudinal z-direction, a high density plasma generated at the area of a high voltage electrode, diffuses into the positive column with the characteristic time $\tau_z{\sim}0.1\;s$. The plasma diffusion velocity at the boundary of high density plasma is $u_D{\sim}10^2\;m/s$ at the time $t{\sim}10^{-6}$ s and the diffusion velocity becomes slow as $u_D{\sim}1\;m/s$ at $t{\sim}10^{-3}\;s$. Therefore, for the long lamp of 1 m, it takes about several seconds for the high density plasma at the area of electrode to diffuse through the whole positive column space.

• Journal of the Korean Vacuum Society
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• v.16 no.5
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• pp.330-337
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• 2007

Influence of glass dielectric property (dielectric constant K, dielectric loss) on the external electrode fluorescent lamps of the dielectric barrier discharge has been investigated with 4-different glasses. Conventional borosilicate glass tubes with $K=5.6{\sim}5.9$ and tan ${\delta}=5.0{\times}10^{-3}{\sim}6.0{\times}10^{-3}$ and aluminosilicate glass tubes with high K=6.6 and low tan ${\delta}=1{\times}10^{-4}$ and soda-lime glass tribes with K=7.7 and tan ${\delta}=1.37{\times}10^{-2}$ have been compared. The high value of dielectric constant K makes the capacitance of external electrode fluorescent lamps intensity and enhances the discharge efficiency. The dielectric loss of tan ${\delta}$ shows the factor of power consumption in the external electrode to induce heats and to be weak in pinhole stability. The aluminosilicate glass tubes of high K and low tan ${\delta}$ have been enhanced by $14{\sim}18%$ in luminance and efficiency in comparison with the conventional borosilicate glass tubes and the aluminosilicate external electrode fluorescent lamps are strong against the pinhole formation. Soda-lime glass tubes with high K and high tan ${\delta}$ are a little favorable in luminance and efficiency and they are very weak in pinhole occurrence.