• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.12
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• pp.1105-1110
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• 2008

In this study, plasma flat fluorescent lamps (FFLs) having two electrode type structures of surface discharge was fabricated by screen printing and were characterized using spectra-radiometer and square pulse power supply. Two types of FFLs (cross-type and line-type electrode structure) were compared with variation of discharge shape and electrode distance.

• Korean Journal of Materials Research
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• v.13 no.4
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• pp.271-278
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• 2003

Conventional backlight for liquid crystal display (LCD) uses mercury which leads to environmental pollution. In this study, characteristics of AC coplanar type mercury-free plasma flat lamp have been studied. Pollution-free Xe-He is adopted as a discharge gas system. Since the Xe gas has a lower efficiency in generating vacuum ultraviolet (VUV) than mercury, the improvement of luminance and luminous efficiency in the Xe gas system is very important. The electrode, dielectric, and phosphor layers constituting lamp are formed on the bottom glass by the screen printing method. The effects of pulse shape, on-time, and pulse frequency on the luminance and luminous efficiency have been examined. For Xe(5%)-He gas, the lamp exhibits higher efficiency with sharper pulse shape, higher peak voltage, and shorter pulse on-time (up to 2 $\mu\textrm{s}$). Higher efficiency and lower consumption of power were obtained at 30 kHz than at 60 kHz. The collision of ion to bottom electrodes is a dominant factor to raise the lamp temperature. Therefore the high voltage and low current discharge system is necessary for reduction of the lamp temperature as well as for enhancement of the luminous efficiency.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1729-1732
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• 2006

We proposed a new Mercury-free Flat Fluorescent Lamp (MFFL) for LCD backlight which shows a wide, stable operating voltage margin, high luminance and efficiency. In this paper, we expanded the single cell with 4 inch diagonal size into the multi-cell for the large size LCD-TV backlight application, examined its operating characteristics and proposed a driving scheme for 2-bit areal selective dimming control.

• Transactions on Electrical and Electronic Materials
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• v.11 no.4
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• pp.186-189
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• 2010

Nano-sized MgO single crystal powders have recently been reported to emit ultraviolet by stimulation of electrons in a vacuum. In this study, nanocrystalline MgO powders were applied to a xenon plasma flat fluorescent lamp (FFL) for a liquid crystal display backlight to improve its emission efficiency through the extra ultraviolet from the nano-MgO crystals. For comparison, a MgO nano-thin film was applied directly on the phosphors inside a lamp panel through e-beam evaporation. Adding MgO nano-crystal powders to the phosphors improved the luminance and efficiency of FFLs by around 20% and MgO nano-crystal coverage of 40% of the phosphor provided the best FFL emission characteristics; however, application of MgO thin film to the phosphors degraded the emission characteristics, even compared to FFLs without MgO. This was due to insufficient ultraviolet stimulation of the phosphors and the crystallinity and low secondary electron coefficient of the MgO.

• Proceedings of the KIEE Conference
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• 2005.11a
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• pp.122-124
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• 2005

The flat panel lamp is used as back light. It is perceived the best type for the wide size LCD of back light system. However, the flat panel lamp has high value of heat. So it need to improve efficiency. Therefore, more researches are requested for the back light of the flat panel lamp. In this paper, the properties of spectrum is investigated according to change in frequency from 30kHz to 60kHz using power supplies voltage with changing from 500V to 700V. As a result, main spectrum peak of plasma showed in 450[nm], 630[nm], 750[nm] and spectrum peak of 750nm is the highest.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1569-1572
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• 2007

A two-dimensional fluid simulation code has been developed in order to investigate discharge phenomena and to improve plasma luminous efficiency in a Hg flat fluorescent lamp (FFL) for an LCD backlight unit. In this study, the method of a two-dimensional fluid simulation for FFL is explained and the simulation results of Hg-Ar-Ne mixture gas are presented for the enhancement of the luminance efficiency. The effects of various parameters, such as driving voltage, frequency, and gas mixture ratio, are investigated. The luminance efficiency increased with increasing fraction of mercury but the increasing fraction of argon did not affect the efficiency much.

• 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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• 2009.10a
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• pp.687-690
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• 2009

It has been recently reported that nano-sized MgO single crystal powders emit ultraviolet by stimulation of electrons under vacuum condition. Therefore, in this study, nano-crystalline MgO powders were applied to a xenon plasma flat fluorescent lamp for LCD backlight to improve emission efficiency of the lamp by help of extra ultraviolet from nano-MgO. For comparison with nano-crystalline MgO powders, MgO nano-thin film was applied directly on phosphors inside a lamp panel through e-beam evaporation The luminance and efficiency of FFL with an addition of MgO nano-crystal powders on phosphors were improved by around 20%. Application of MgO thin film to phosphors worsened the emission characteristics of FFLs, even rather than FFL without MgO. The reason came from insufficient stimulation of phosphors by UV, crystallinity of MgO, and low secondary electron coefficient.

• 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.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.05a
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• pp.82-85
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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.