• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.779-782
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• 2004

Establishing and maintaining optimum lamp operating temperature is critically important in backlight systems for large area displays. The information presented in this paper is based upon work completed for a tiled 37.5" AM LCD, plus projections for a 37.5", 42" & 50" monolithic display. Due to the size of the units, a requirement for highly collimated light and a requirement for high brightness, >550 nits at the display surface, significant wattage is required which generates high heat levels in the backlight display assembly and potentially, at the display rear surface. Uniformity of illumination becomes an important element in the system design because of the large area involved.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1515-1518
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• 2007

We demonstrate a high color gamut liquid crystal display (LCD) system (>100 %) by using a precompensated tri-chromatic LED-backlight module over a temperature range of (25 to $70^{\circ}C$), whose pre-compensated optical characteristic balances the spectral redshift and intensity decrease due to the temperature rising during operation.

• Journal of Korea Society of Industrial Information Systems
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• v.12 no.3
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• pp.116-123
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• 2007

Despite the number of backlight manufacturer is increased as the market of flat panel display equipments and related development devices is enlarged, the inspection based on the human eye is still used in many backlight production lines. The defects such as particle, spot and scratch on the light emitting surface of the backlight prevent the LCD device from displaying the colors correctly. From that manual inspection it is difficult to maintain the quality of backlight consistently because the accuracy and the speed of the inspection may change with the physical condition of the operater. In this paper we studied on the development of automatic backlight surface defect inspection system. For this, we made up of the computer vision system and we developed the main program with various user interfaces to operate the inspection system effectively. And we developed the image processing module to extract the defect information. Furthermore, we presented the labeling process to reconstruct defect regions using the labeling table and the defect index. From the experimental results, we found that our system can detect all defect regions identified from human eye and it is sufficient to substitute for the conventional surface inspection.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1503-1506
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• 2008

A novel white-LED (light emitting diode) backlight system for 46"LCD TVs which involves the current controlled X-Y channel driving method is proposed in this paper. There are two problems related to the LED current in the conventional X-Y channel driving driven by a constant voltage source. To solve these problems, a real time current sensing system is applied to the conventional one and the time-division current sensing method is employed.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1326-1329
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• 2009

In large-area LCD displays, we have developed two new control technologies for high-power LED backlight. The Novel control technology called scanning control and local gray control. In addition, a conceptual display system power management was developed. We have implemented high power-LED module driving system which can achieve power saving and cost down. Finally, we designed LED light-bar module of the side type as a backlight source. It not only achieved light & thin but also reduced the quantity of LEDs.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04a
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• pp.173-176
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• 2000

we analyzed multiple ray tracing in the highly scattering optical transmission(HSOT) polymer plate by means of the Monte carlo simulation. Light transmission behavior in the light guide was simulated by a 3-dimensional ray tracing program considering scattering angle given by the Mie theory and mean free path. To improve the uniformity of the conventional HSOT backlight unit, We employed additionally dot patterns. For the proposed structure, we calculated the light transmission behavior and obtained a bright and uniform backlight unit for a large size LCD panel of more than 12 inch.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.363-366
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• 2007

A new current control technique called Amplitude Shift Modulation (ASM) for cold cathode fluorescent lamps (CCFL) has been developed. This new technique sets and continuously controls the current of each individual CCFL in an LCD backlight lamp array.

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.2
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• pp.96-102
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• 2008

In a large screen sized LCD-TV, a backlight system with only one cold cathode fluorescent lamp(CCFL) can not meet brightness specification. Thus, considerable numbers of CCFLs are used to meet brightness specification. In this paper, the design guide for the inverter transformer which can drive 4 CCFLs instantaneously is presented. With the presented design, the inverter transformer that guarantee identical lamp currents under the nonidentical lamp characteristic condition, can be implemented easily. The developed inverter transformer is adopted in a 42" LCD-TV backlight. The experimental results are presented to show the validity of the presented design guide.

• The Transactions of the Korean Institute of Power Electronics
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• v.15 no.4
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• pp.319-326
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• 2010

The power supply devices for reducing the size of the LCD TV are increasingly required for high efficiency and highe power density. Recently, the LED backlight of the LCD TV comes into the spotlight for LCD TV, because the conventional CCFL backlight has difficult to use constantly according to the mercury restrictions. And In this paper, the LLC resonant converter using the planar transformer for slim-type LED backlight of LCD TV is presented and verified through an experimental prototype for 47 inch LCD TVs with LED backlight system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.432-432
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• 2007

We studied optical simulation method for ultra slim backlight system. We designed 0.7mm thickness light guide plate and combined 48 white color LEDs for 12 inch wide size TFT-LCD. We designed flat shape PMMA light guide plate with both side patterned. It have vertical prism shape on upper side and ellipse dot pattern on the other side. We targeted 4500 nit brightness and uniform emission characteristic without hot spot or dark area. At first, we designed uniform emission area with more high brightness in center area and then, debugged light entering hot spot zone and direction of outgoing light flux. Although it was designing step, we obtained good result with reverse prism optical sheet and it had good repeatability because it was based on the stamper method in injection process without laser engraving or micro groove engraving method.