• Korean Journal of Plant Tissue Culture
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• v.27 no.1
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• pp.71-75
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• 2000

To clarify the possibility of plant production under red, green. blue, and red+blue using light emitting diodes (LEDs) and fluorescent lamps (control), the effects of light quality on the growth and morphogenesis of in vitro seedlings in Piatycodon grandiflorum were examined. The plantlets grown under the LEDs resulted in taller plants with greater stem than fluorescent lamps. The shortest shoot length, 3.8 cm, was observed in the control and the longest one, 13.4 cm, in the red light. But the shoot length was 5.6 cm under red LED with supplemental blue(red+blue light). This results indicate that red LED may be suitable, in proper combination with other wavelengths of light. The root length under red light was significantly smaller among the treatments. The plantlets grown under red+blue light had lower shoot dry weight, higher dry matter than other lights-grown plantlets. Among the various growth parameters measered, there was an indication that leaf area was controlled by the LEDs. Leaf area of a plantlets developing under green light was about 2.4 times wider than that of plantlets grown under red LED (10.1 $\textrm{cm}^2$ in area). The dry matter rate per plantlet among the treatments was greater in plantlets grown under the red/blue LEDs in comparison with that grown under other LEDs. Chlorophyll contents in plantlets grown under the red, green, blue and red/blue LEDs were 2%, 7% 20% and 10% lower, respectively, than those in plant grown under fluorescent lamps.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.1068-1071
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• 2004

We report the techniques to obtain the high uniformity of the phosphor film thickness in the cold cathode fluorescent lamps, which are widely used as a back-light for the liquid crystal display. The thickness variation of the phosphor layer was sensitive to blowing conditions. The optimum conditions were obtained at flow rate of 15 sccm for 30 min at 40 $^{\circ}C$. The optimum and uniform thickness of a phosphor layer gives good luminous output.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.434-436
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• 1996

This paper investigates the optimal design of an electronic ballast of half bridge inverter type in consideration of the variation of ambient temperatures for a 15[W] triple-type compact fluorescent lamp. The performances of electronic ballasts under different values or the capacitance ratio in the resonant tank circuit are compared with each other in the practical temperature range between 15[$^{\circ}C$] and 35[$^{\circ}C$] to determine its optimum value. As a result, the optimum value is found to be such that $C_1/C_2=10$ at which value starting of the lamp is most stable and light output reaches its maximum value with lowest variation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.7
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• pp.1275-1281
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• 2007

The discharge phenomena in a flat fluorescent lamp for the backlight unit of liquid crystal displays are simulated by sung a two-dimensional fluid model. The numerical methods for the calculation of plasma dynamics and the radiation transport are introduced for the discharge simulation and for the transmission of the vacuum ultraviolet lights. The simulation results are presented to compare the luminance and the luminance efficacy with the variation of gas pressure, gas mixture ratio, driving voltage, and frequency.

• Journal of the Korean Professional Engineers Association
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• v.42 no.5
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• pp.41-45
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• 2009

The last century of lighting has been dominated by incandescent, fluorescent and high-intensity discharge(HID)light sources. In the late 1970's, after green LEDs were invented, Dr. Ching Tang at Eastman Kodak discovered that sending an electrical impulse through carbon compound caused such material glow. Present day LED commercial packages have reached 100 lm/W, comparable to the efficacies of fluorescent and certain HID lamps. LED products available today are market as "Green-Industry" but actually low light output compared to typical light sources. The combination of high price and low light output make them a poor replacement for current technology. It is very important to compare new LED products to the most efficient conventional technology that could be used for any specific application. As LED technology advances, costs decrease, and efficiency improves, LEDs will build market share in the general illumination market.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1189-1192
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• 2008

A new mercury-free flat fluorescent lamp with a single cell having dimension 2.2inches across the diagonal, had been developed which shows a wide, stable operating voltage margin, high luminance and luminous efficacy by adopting the bipolar pulse drive scheme. In this paper, the single cell is expanded into a multi-structured configuration to realize a 32inch sized panel across the diagonal by a simple repetition of the single cells. A driving scheme is proposed for a 2-bit areal selective dimming using dual auxiliary electrodes and bipolar drive scheme.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1412-1414
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• 2006

We study on the Electro Optical Properties of the EEFL (External Electrode Fluorescent Lamp) Backlight system is based on the lamp type characteristics and diameter of the lamp tube under the equal manufacturing of the lamps. In this contribution, through the analysis of the different lamp type and diameter of the lamp tube gain the effective luminance and reduce the lamp voltage from aspect in the electro optical properties with EEFL and LCD backlight system.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1374-1377
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• 2006

The voltage distribution of an external electrode fluorescent lamp(EEFL) having a gas pressure of 50 torr and a gas composition of Ne:Ar with a ratio of 90:10 has been estimated by varying the distance between the two external electrodes and monitoring the change of the lamp voltage. The estimated voltage gradient, which represents the electric field in the positive column of the EEFL, was very sensitive to the electrode area of EEFL and was in the range of $13\;{\sim}\;27\;V/cm$ at the electrode length of $15\;{\sim}\;31\;mm$. Changing the lamp current in the range $3\;{\sim}\;5\;mA$ did not make noticeable difference in the electric field of the positive column. Theses results may serve as basic data for the optimization of electric and optic characteristics of EEFL.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1386-1389
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• 2006

In this study, a plasma flat fluorescent lamp having a new structure was fabricated by screen printing technique. Coplanar types of silver electrodes with a dielectric layer were screen-printed on a rear glass plate, and then fired at $550^{\circ}C$ and $580^{\circ}C$, respectively. Phosphor was spin-coated on the dielectric layer with firing at $490^{\circ}C$. Several types of lamps were designed and its properties wee investigated with electrode shape, gas pressure, etc.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.533-535
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• 2002

Electrode formation methods such as a metal-taping, a electrolytic plating, and a metal-paste melt-bonding, are introduced for an external electrode fluorescent lamp. The characteristics of luminance and efficiency for various external electrode types have been investigated.