• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.1
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• pp.47-58
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• 1996

An object color can be seen differently under the various outer illuminants. However, human visual system has color constnacy that the object color can be seen constantly under the different outer illuminants. When the viewer watches TV under specific that the object color can be seen constantly under the different outer illuminants. When the viewer bathes TV under specific outer illuminants, he perceives distortes color due to the emitting specturm of outer illuminants as well as the radiation of CPT itself. Namely, when the outer illuminants such as fluorescent and incandescent lamps incident on CPT, brightness, saturation, hue, itself. Namely, when the outer iluminants such as fluorescent and incandescent lamps incident on CPT, brightness, saturation, hue, and contrast on color pictures are changend, he perceives distortedcolr fromthe original color. In this paper color enhancement algorithm based on light intensity and outer light decision funtion using RGB sensor was proposed. The implemented TV of proposed algorithm has higher visual quality at the view point of human visual system and more vivid than that ofcoventional color TV.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.165-168
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• 2007

Electrooptic characteristics of Xe-type flat fluorescent lamps (FFL) have been investigated by using a Q-V Lissajous method. It was found that the luminance of the Mgo-coated FFL became more than doubled compared to normal FFLs operated at the same driving voltage, indicating the possibility of the efficacy improvement in the MgO-coated FFLs. Change in the driving condition, in particular, the duty ratio had effects on the electrooptic properties, and it was found that the duty ratio of 50% was the optimum condition from the viewpoints of the efficacy and the lamp voltage.

• Proceedings of the KIEE Conference
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• 2007.10c
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• pp.166-168
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• 2007

A dimmable ballast system for the electrodeless fluorescent lamp is proposed. The proposed scheme is composed of the electronic ballast and the wireless communication part. They both are realized with one EPLD (Erasable Programmable Logic Device). The dimming levels of each lamps can be controlled by a management system through wireless communication technology. 10 ballasts are used for the group lighting system and the experiment results show the system works well.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.05a
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• pp.105-108
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• 2007

Because of energy efficiency and environment-friendly characteristics, demands of white LED are being increased in various fields. White LED is being observed as next-generation light sources to alternate incandescent and fluorescent lamps so that the studies on white LED are being processed continuously. This study investigates technical developments and market movements of white LED to evaluate technical characteristics and to analyze performances data by comparing prototypes of white LEDs. And comparing efficiency of white LED with that of incandescent and fluorescent lamps, this study aimed at presentation of compatible standards for future LEDs.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.1126-1128
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• 2001

A single-stage high-power-factor electron ic ballast operating in critical conduction mode is presented in this paper. The proposed topology is based on integration of a boost-like converter and a LCC Type half-bridge serial resonant inverter. The power-factor-correction(PFC) stage is a boost-like converter operating in critical conduction mode for positive and negative half cycle voltage respectively at line frequency (60Hz) so that a high power factor is achieved naturally. The simulated and experimental results for 100w fluorescent lamps operating at 42kHz switching frequency and 220V line voltage have been obtained.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.1135-1138
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• 2003

A direct light type backlight for large-area LCD-TVs using External Electrode Fluorescent Lamps (EEFLs) has been developed. The brightness was $450cd/m^{2}$(nit) and the luminous uniformity (max/min) was 1.3. The mechanical design of backlight was optimized and the reliability of lamps was secured. As a result, the possibility of backlight with EEFLs for large area LCD-TVs was sufficiently proved.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.908-909
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• 2008

A kind of fluorescent lamps CCFL(Cold Cathod Fluorescent Lamp) is used for backlight of LCD and the demand of backlight for TV is getting more. CCFL is also used in a backlight for TFT-LCD panel. BLU(Backlight Unit) has lots of components so it looks a electrical product. As the size of LCD display is larger with increasing of the demand, to drive CCFL inverter is more important. Therefore, a sort of modeling to drive 4 lamps with a transformer is used and we have a simulation test with proposed modeling so we can take some data from the test. The utility of the proposed modeling is verified through using for 30-inch LCD backlight with the data.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.2085-2087
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• 1998

This paper presents the design method of a dimming electronic ballast for fluorescent lamps using a frequency control IC, and investigates the effects of circuit variables on its dimming characteristics. It is shown that effective dimming is possible with IC IR2151 for frequency control, and this leads to a feasible design of more smaller and cheaper dimming ballast. Five ballasts different in the values of the series inductance and capactance are designed, and their dimming characteristics are compared. As the result, the dimming range becomes more broader as the series inductance gets smaller and the capacitance larger. Thus appropriate selection of the values of L and C should be made according to the types of application site.

• Journal of Industrial Technology
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• v.23 no.A
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• pp.35-39
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• 2003

There are many kinds of electronic ballast for various kinks of fluorescent lamps. The PFC(Power Factor Correction) circuit in electronic ballast is classified in two types. One is the active PFC and the other is the passive PFC circuit. The active type PFC is higher than the passive type, but the cost of the passive type is cheaper than the active type. In this study, we introduced the modified passive PFC method which is called semi-boost PFC, and then we analyzed and experimented the electronic ballast which is composed of the semi-boost PFC, half-bridge, and LCC resonant tank. Experimental results showed that the $$PF{\geq_-}0.98$$, $$CF{\leq_-}1.4$$ and input current $THD{\approx}15%$.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.12 no.4
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• pp.1-5
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• 1998

This paper reports the developement of the protection circuit of electronic starter for fluorescent lamps of end-of-life. The key point of this paper is to protect for lamp of end-of-life by four operational amplifiers (OP AMP) and one solid state relay (SSR). In this paper we simulated the circuit by PSpice and compared with experimental results.