• Journal of the Society of Disaster Information
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• v.17 no.1
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• pp.184-193
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• 2021

Purpose: In this study, since the operation principle of the CCFL Exit light is the same as that of general lighting equipment, the characteristics of the CCFL Exit light were analyzed by deriving test items that can affect the characteristics of the light source from the KS standard, which is the standard for lamp ballast performance certification of general lighting equipment. Method: The samples used in the experiment were performed on products of two manufacturers for each size, such as large, medium, and small, and the test items were power factor, crest factor, and current harmonic distortion. Result: As a result of the experiment, the power factor showed a value between 0.4 and 0.6 in all samples, which was smaller than the 0.9 value set by KS. The crest factor ranged from 3.6 to 3.7 for large, 4.4 to 4.7 for medium, and 3.5 to 3.7 for small. It showed a value more than two times higher than the KS standard of 1.7. Current total harmonic distortion ranged from 81% to 110%, and considering that the KS standard was less than 20%, it could be confirmed that all samples had a value significantly exceeding the KS standard. Conclusion: The crest factor and current total harmonic distortion may affect the temperature rise of the light source and the burnout of the device. When developing an exit light, if this item is developed within the scope of the KS standard, the quality improvement and maintenance of the exit light will be greatly improved.

• The Transactions of the Korean Institute of Power Electronics
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• v.15 no.1
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• pp.52-59
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• 2010

The conventional CCFL (Cold Cathode Fluorescent Lamp) inverter used in the backlight unit for LCD-TV, composed of the three power stage, can degrade the whole power conversion efficiency. In this paper, a novel scheme to drive the CCFL, composed only of the two power stage without using a dc/dc power stage, is proposed to enhance the whole power conversion efficiency. By adopting the proposed "4-in-1 Transformer", the current balance and the simultaneous ignition among the four CCFL lamp are assured with the one inverter circuit. The proposed scheme features the simple circuit structure, which can save the volume and the cost in the LCD backlight unit. Design considerations are discussed and design procedures are derived. Experimental results of the proposed scheme for 40" LCD-TV are presented to confirm the theoretical analysis.

• 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.

• Korean Journal of Materials Research
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• v.19 no.3
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• pp.163-168
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• 2009

$Eu^{3+}$-doped $Y_2O_3$ red phosphor was synthesized in a flux method using the chemicals $Y_2O_3,\;Eu_2O_3,\;H_3BO_3$ and $BaCl_2{\cdot}2H_2O$. The effect of a flux addition on the preparation of $Y_2O_3:Eu_{3+}$ red phosphor used as a cold cathode fluorescence lamp was investigated. $H_3BO_3$ and $BaCl_2{\cdot}2H_2O$ fluxes were used due to their different melting points. The crystallinity, thermal properties, morphology, and emission characteristics were measured using XRD, TG-DTA, SEM, and a photo-excited spectrometer. Under UV excitation of 254 nm, $Eu_2O_3$ 3.7 mol% doped $Y_2O_3$ exhibited a strong narrow-band red emission, peaking at 612 nm. From this result, the phosphor synthesized by firing $Y_2O_3$ with 3.7 mol% of $Eu_2O_3$, 0.25 mol% of $H_3BO_3$ and 0.5 mol% of $BaCl_2{\cdot}2H_2O$ fluxes at $1400^{\circ}C$ for 2 hours had a larger particle size of $4{\mu}m$ on average compared to the phosphor of the $H_3BO_3$ flux alone. In addition, a phosphor synthesized by the two fluxes together had a rounder corner shape, which led to the maximum emission intensity.