• 전력전자학회논문지
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• 제13권5호
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• pp.376-382
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• 2008

본 논문에서는 LCD(liquid crystal display)에서의 모션 블러 현상을 저감 시킬 수 있는 scanning backlight unit을 면광원을 사용하여 설계 및 제작 하였다. 면광원은 그 구조의 단순함과 BLU(backlight unit) 조립성과 구동의 간편성으로 인해 차세대 BLU의 신규 광원으로 각광 받고 있다. 램프 휘도를 제어하기 위하여 스캔 구동 시 램프의 on-time을 조절하였으며 실험결과 램프 휘도가 선형적으로 변화되고 넓은 범위의 휘도 제어가 가능함을 확인하였다.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2009년도 정보통신설비 학술대회
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• pp.86-87
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• 2009

LED backlight for LCD TV is a great alternative to CCFL backlight due to its low power consumption and flexible arrangement. Various LED backlight configurations are being used to control the backlight locally in order to achieve both power efficiency and high contrast. However, the relatively small spatial resolution of the backlight system results in showing artifacts of backlight control that is acknowledgeable to human vision. Moreover, such artifacts get worse between temporal frames. In this paper we present a method of decreasing such temporal artifacts with a Human Visual System(HVS) approach to minimize distortion caused by local backlight dimming.

• 대한전자공학회논문지SP
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• 제48권4호
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• pp.38-48
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• 2011

Backlight Profile과 Image Pixel의 Homogeneity 분석을 통한 Block 단위 LCD Backlight Nonideality 및 Crosstalk Compensation 방안이 제안되었다. Image에 따라 Block Size 및 연산에서 제외되는 Block 범위 그리고 연산에 고려되는 Backlight 범위를 최적화하여, 화질을 유지하면서 연산량을 최소화시켰다. 실제 영상을 바탕으로 하는 Simulation을 통해 제안된 Compensation 연산량과 화질이 평가되었다.

• Journal of the Optical Society of Korea
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• 제12권3호
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• pp.174-177
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• 2008

The luminance properties of FFL(Flat Fluorescent Lamp) backlights have been investigated in detail for the first time. The on-axis luminance gain as well as viewing-angle characteristics on various combinations of optical films were obtained from FFL backlight and compared to the results of conventional CCFL(cold-cathode fluorescent lamps) backlights. It was found that the on-axis luminance gains achieved by using optical films in the FFL backlight were lower than those in the CCFL backlight indicating that the recycling processes occurring between optical films and light sources/reflection sheet are not so effective in the FFL backlight due to the much larger area of, and thus higher absorption probability of the FFL. This result suggests that new optical films should be developed for FFL backlight and other flat-lamp backlight technologies.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.795-798
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• 2004

After showing 32 inch two-dimensionally integrated fluorescent lamp (TIFL) and its module at SID '04, 40 inch TIFL and its module of prototype have been developed at the first time. It is the biggest size in the world as well as has a backlight unit without BEF optical film. The luminance of TIFL is 14000 nit at 190 watt power consumption and its luminous efficacy is 51 lumen/watt. The use of TIFL simplifies backlight assembly process and removes high price optical sheets. As a result, LCD TV, used by TIFL, is rapidly going to expand its market share in the large size TV area.

• Journal of Information Display
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• 제11권4호
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• pp.173-181
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• 2010

In this paper, light-emitting-diode (LED) backlight driving circuits and dimming method for medium-sized and large liquid crystal displays (LCDs) are proposed. The double loop control method, the intelligent-phase-shifted PWM dimming method, the fast-switching current regulator, and the current matching techniques are proposed to improve not only the current regulation characteristics and the power efficiency but also the current matching characteristics and the transient response of the LED current. The brightness of the backlight using the proposed local dimming method was determined from the histogram of the local block to reduce the power consumption of the backlight without image distortion. The measured maximum power efficiency of the LED backlight driving circuit for medium-sized LCDs was 90%, and the simulation results showed an 88% maximum power efficiency of the LED backlight driving circuit for large LCDs. The maximum backlight power-saving ratio of the proposed dimming method was 41.7% in the simulation with a high-contrast image. The experiment and simulation results showed that the performance of LEDs as LCD backlight units (BLUs) improved with the proposed circuits and method.

• Transactions on Electrical and Electronic Materials
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• 제9권1호
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• pp.16-19
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• 2008

In this study, it was investigated about optical simulation in direct-type backlight design. Direct-type backlight has been used high-brightness backlight such as medical LCD application. The key parameter in designing direct-type backlight was consists of three geometrical dimension such as the distance of two lamps, the gap of lamp and reflection plate and the number of lamps. It has many of variations in optical design and it causes the different properties in backlight system. It shows the best values of above parameters; 26 mm of the distance of two lamps, 4.5 mm of the gap of lamp and reflection plate and 16 lamps. And we produced the specimen as above condition, and acquired good result in backlight such as the value of the brightness is 6423 nit in center of emission area and less than 5 % in brightness uniformity. It shows the effective ways of designing backlight system using optical simulation method for medical LCD application.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.415-415
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• 2007

In this study. it was investigated about optical simulation in direct-type backlight design. Direct-type backlight has been used high-brightness backlight such as LCD television application. The key parameter in designing direct-type backlight was consists of three geometrical dimension such as the distance of two lamps. the gap of lamp and reflection plate and the number of lamps. It has many variation in optical design and it causes the different properties in backlight system. It shows the best values of above parameters; 26mm of the distance of two lamps. 4.5mm of the gap of lamp and reflection plate and 16 lamps. And we produced the specimen as above condition. and acquired good result in backlight such as the value of the brightness is 6436 nit in center of emission area and less than 5% in brightness uniformity. It shows the effective ways of designing backlight system using optical simulation method.

• 조명전기설비학회논문지
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• 제26권9호
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• pp.8-17
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• 2012

This paper proposes high performance control of light emitting diode(LED) drive system for liquid crystal display(LCD) backlight. The CCFL(cold cathode fluorescent lamp)was used to a conventional LCD backlight. Due to improvement on luminous efficiency, long life and wide color gamut, LED has gradually substituted for CCFL as backlight. The backlight using LED is necessary to use many LED. For that reason, the LED backlight is using a lot of LED driving circuits. The many LED driving circuit is generated a current deviation between LED. Eventually, it is caused brightness deviation between LED. Therefore, this paper improves the current deviation using transformer and balancing capacitor to solve this problem. Also, for accurate and uniform brightness control, this paper is applied the artificial intelligent control to a dimming control. This paper is compared with conventional system, and validity of this paper proves through that result.

• 전력전자학회논문지
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• 제12권5호
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• pp.416-423
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• 2007

LCD backlight 인버터의 Cold Cathode Fluorescent Lamp(CCFL)를 구동하기 위해 승압 기능과 전류 평형 효과를 동시에 갖는 트랜스포머에서 부피 및 원가 저감 효과를 갖는 새로운 구조의 트랜스포머를 제안하였다. 제안된 트랜스포머의 타당성을 검증하기 위해 실제 40인치 LCD backlight 인버터에 적용하여 실험을 수행하였다.