• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.428-428
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• 2007

In this study, It was studied about the luminance characteristics of 17inch direct-type back light using EEFL(External Electrode Fluorescent Lamp). EEFI has a long life time because the electrode is installed outside of lamp. And it is produced low price than conventional CCFL. It does not need process of installing internal electrode. But EEFL technology has several problems such as difficulty of design driving inverter, and prevents leckage current along the skin of lamps. Therefore, by the optimizing of inverter properties, 7525 nit center luminance was acquired in almost same power consumption condition. It was almost same luminance in CCFL backlight unit. And it was operated stably in low operating temperature such as the value of $40^{\circ}C$, so that it was adopted in conventional LCD-TV application.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.441-442
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• 2009

A wavelength multiplexing based stereoscopic 3D-LCD will be introduced. A new 120 Hz scanning RGB-backlight unit was developed. This backlight module was combined with a standard 120Hz LCD. The 3D-LCD based on interference filter glasses offers an outstanding channel separation and a wide viewing angl.

• Proceedings of the KIPE Conference
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• 2007.11a
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• pp.53-55
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• 2007

This paper describes an implementation of a wide-range dimming controller of a LED backlight for Avionics applications such as the control data unit(CDU) and multi-function display(MFD). A feedback controller using a light sensor is proposed to control the brightness in the low dimming range. The proposed controller provides an improved control performance in the wide dimming range of 1:3000 even under the temperature variations. The experimental results are provided to show the effectiveness of the proposed control system.

• Journal of the Optical Society of Korea
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• v.13 no.2
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• pp.256-260
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• 2009

The optical performance of the reflective polarizer was investigated over three kinds of direct-lit backlights and/or different configurations of the optical sheets. The optical gain factor achieved by using the reflective polarizer increased as the diffuse nature of the optical sheet was enhanced, because of the more efficient polarization conversion. In addition, the gain factor decreased substantially in flat-lamp backlights compared to tubular-lamp backlights, which was ascribed to the high loss factor during the polarization recycling process due to the complex structure and large area of flat lamps. All these results suggested that reducing the loss factor of the backlight is very important for efficient polarization conversion and thus high optical gain of the reflective polarizer.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.1045-1048
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• 2007

We mainly report recent progress in backlight unit (BLU) for liquid crystal display (LCD) using printed carbon nanotubes (CNTs) including top-gate and lateral gate structures. Lighting performances of CNTBLU and longevity of printed CNT emitters are intensively discussed. Selected issues related with field emission display (FED) using the same emitters also are presented.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.221-224
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• 2003

Recently, the market share of the thin-film-transistor liquid-crystalline-display (TFT-LCD) is growing rapidly in display device market. The backlight unit is used as a light source of TFT-LCD module. A light-guide is one of several important components of backlight unit. The manufacturing technology and optical system design of the light guide is very sensitive to quality and cost of the TFT-LCD module. In the present study a new manufacturing method which is called as direct surface forming(DSF) has been tested under various conditions. The result of this test, V-groove pattern shows different shapes depends on the temperature of mold surface, contact time of mold and depth of V-groove.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.4
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• pp.495-498
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• 2009

To improve the efficiency of the high voltage cable for BLU(backlight unit) of TFT-LCD(Thin Film Transistor-Liquid Crystal Display), the analysis for the trial products(UL3239, UL3633) is conducted by using SEM(scanning electron microscope) and EDX(Energy Dispersive X-ray Spectroscopy). The result that it is possible to accumulate the know-how to about stranding pitch through effective improvement of stranding process. The troubles which are the badness of withstanding voltage and tensile strength etc. are solved by development of excellent material. Furthermore, phenomenon of conductor unfasten in the harness work is solved by improvement of the stranding wire process.

• Journal of Information Display
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• v.7 no.4
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• pp.1-4
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• 2006

The optical performances of rounded prism films were investigated using a ray tracing technique. The angular distribution of the luminous intensity was obtained as functions of the prism pitch and the curvature of rounded apex and valley of prism arrays. The gain of the on-axis luminance decreased with decreasing curvature (increasing diameter) and pitch. The existence of the curved area on the prism film decreased the recycling efficiency of the prism film, i.e., the rays which would otherwise have been recycled through total internal reflections via the prism surfaces were refracted on the curved regions and redirected toward directions other than the on-axis direction. Quantitative correlation between the luminance gain and the curvature in addition to the prism pitch was obtained, which might serve as basic data for the optimization of prism films and the manufacturing processes.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1343-1346
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• 2006

Optical performances of micro-pyramid arrays were simulated by ray tracing technique for the application of backlight unit of LCD. The angular distribution of the luminance and the on-axis luminance gain depended on the apex angle, the refractive index, and the density of micro-pyramids. The on-axis luminance reached a maximum when the apex angle was $90^{\circ}$. It also increased as the density and the refractive index of micro-pyramids increased. The present result showed that highly-efficient optical sheet might become realized by adopting micropyramid array and corresponding development of manufacturing processes.

• Journal of Information Display
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• v.10 no.2
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• pp.49-53
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• 2009

In this study, a very small LED packaging lead frame with a low thermal resistance was developed. The cost of the package process was reduced by the use of many small LED lamps, which increased the light emission efficiency. Compared to the large lead frame lamp, however, the optical property of the small LED packaging lead frame lamp was not sufficiently improved because its reflection structure was changed and its reflection area was reduced. The luminous efficiency of the LED lamp reaches 58 lm/W at the current density of 0.16 A/$cm^2$. Using the LED lamps, 46-inch LCD BLU was manufactured. The BLU-made LED lamps have a low power consumption of 146 W and have a slim (10-mm-thick) BLU, keeping good uniformity in terms of brightness, and maintaining good thermal properties.