• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1153-1155
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• 2008

Color dimming technology has been developed for high color gamut and aggressive power saving. In our new algorithm, we proposed a new concept of 'color class', with which it is possible to control RGB color luminance effectively and exactly. We reached color gamut of 155% of NTSC 1976 and reduced power consumption under 100 watt for 46 inch LCD.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.10
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• pp.1513-1517
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• 2012

As demands for green industry increase, this paper proposes a power control technique that can substitute pre -existing CCFL(Cold Cathode Fluorescent Lamp) and optimize power consumption of LED BLU. This technique is designing LED driver circuit that make a DC-DC output voltage(VLED) to have a linear control function for a supply voltage of LED string. The proposed LED driver have an advantage that can increase or decrease a DC-DC output voltage compared with conventional LED driver. The designed LED driver circuit was designed using 0.35um CMOS technology. And its operation was verified through simulation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.3
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• pp.1308-1312
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• 2011

CCFL(Cold Cathode Fluorescent Lamp)for BLU of LCD and special lighting has been widely utilized. The removal of oxide film formed on electrode of CCFL in manufacturing process is required. In this pape Plasma treatment was carried out to remove the oxide film. To ensure the optimum process, the analysis of sheet resistance, XRD, AFM and solder test was conducted. A minimum sheet resistance and the maximum percentage of the solder coverage ratio were measured in optimal process conditions such as plasma power consumption 600W and processing time of 70 seconds. As the plasma treatment is confirmed to be due to removal of copper oxide, this process is expected to be used as a treatment of electrode for CCFL.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1499-1500
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• 2008

최근에 LCD의 후면광원으로 LED를 채용하는 경우가 증가하고 있다. 이러한 LED를 Back Light으로 사용할 경우 일정한 휘도의 유지와 색좌표의 보정은 고급제품의 경우 채용이 증가하고 있다. 본 연구에서는 LCD Monitor용 LED BLU의 CMS(Color Management System)을 개발하기 위하여 1.5W R,G,G,,B가 하나의 PKG에 들어있는 LED를 이용하여 Direct type의 Back Light Unit을 개발하였다. 방열 및 휘도 균일도를 고려하여 LED part를 설계, 개발하였고 LED를 PWM으로 구동하기 위하여 Switching circuit이 포함되는 구동회로 부분을 설계, 개발 하였다. 또한 Color Sensor와 CMS IC를 사용하여 Color를 Control하고 휘도도 컨트롤하는 제어회로 부분도 개발을 하였다. CMS 기능의 제어회로 부분을 개발하기 위하여 MicroController를 사용하였으며 CMS IC와의 통신을 위한 부분도 개발하였다. 이러한 구성을 개발하여 시제품을 직접 제작하였다. 평가를 위하여 성능시험을 실시하였고 광학적인 평가도 시행하였다. 제작된 시제품은 L558 x W359 x H30 으로 하였다. 휘도는 목표휘도를 이루었으며 균일도는 85% 이상이 되었다.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.277-280
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• 2007

Field emission-back light unit (FE-BLU) was fabricated using carbon nanotube (CNT) emitter. Local dimming and local brightening techniques were achieved, which results in very high contrast ratio. In addition, the motion blur phenomenon, one of the serious problems of liquid crystal display (LCD) with cold cathode fluorescent lamp (CCFL)-BLU, was removed from LCD-TV by using FE-BLU.

• Korean Journal of Optics and Photonics
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• v.18 no.6
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• pp.401-409
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• 2007

A new sheet of back light unit(BLU) to reduce the number of sheets and enhance the optical performances of direct back light unit(BLU) in a liquid crystal display is proposed and designed. In order to improve the straightness and spatial uniformity of brightness of the BLU, we design the new sheet with linear arrays of complicated bar prism by using the fusion of cylindrical lens and bar prism. Then, we investigate and analyze various optical performances of a BLU including the new sheet through an illumination optical system design program. From these results, we determine the optimum geometrical structure of the sheet. Under the optimum condition, the luminance efficiency and spatial uniformity of luminance of the BLU are 53.5% and 83.5% respectively. And the vertical and horizontal widths of the angular luminance distribution are $90^{\circ}$ and $112.5^{\circ}$ respectively. Finally we have fabricated a new BLU sheet according to this design shape by using an ordinary resins.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.61 no.2
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• pp.93-96
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• 2012

We have designed high performance prism light-guide plate (LGP) in 17 inch TFT-LCD. In test result to embody high brightness BLU in case of LGP of base and upper surface with 17 inch, thickness 8mm adding prism construct. Using optical simulation, we forecast the brightness and uniformity in LGP with prism structure. And we adopted novel injection mold method and Nickel stamper to make actual evolution sample. Novel injection mold process has steady heating time zone in heat cycle time of injection mold process. For this novel heat cycle control, we achieved above 90[%] height prism structure as our design. It is superior brightness improvement than previous that of printing form about some 20[%] and in this course to embody actual material it succeeded prism LGP production by 17 inch injection form process.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.5
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• pp.76-81
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• 2012

The continuing demand for increasingly slimmer and brighter liquid crystal display(LCD) panels has led to an increased focus on the role of the light guide panels(LGPs) or optical films that are used to obtain diffuse, uniform light from the backlight unit(BLU). And the most basic process in the production of such BLU components is the micromachining. LCD BLUs comprise various optical elements such as a LGP, diffuser sheet, prism sheet, and protector sheet with micro patterns. High aspect ratio patterns are required to reduce the number of sheets and enhance light efficiency, but there is a limit to the aspect ratio achievable for a given material and cutting tool. Therefore, this study comprised a series of experimental evaluations conducted to determine the machining feasibility in microcutting various aspect ratio patterns on electroless nickel plated die materials when using single-crystal diamond tools. Cutting performance was evaluated at various cutting speeds and depths of cut using different machining methods and machine tools.

• 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.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.71-71
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• 2009

Recently several LCD TV makers including Samsung, LG and Sony actively have released LED LCD TV models on market. LED LCD TV is just which applied LED BLUs so that its color contrast ratio fairly enhance up to 1 million:1 and its thickness minimize to a few mm. Even this aspect seems somewhat to be each panel maker's strategies for prior market occupations on whole TV market. Without regard to the reasons, we do obviously meet a new era of technically advanced LCD TV. However we have still lots of problems or issues which we must overcome technically including LED chip/packaging process, secondary optics treatment, heat managements and cost reduction issues. Here I would like to forecast market volume and trend of LED LCD TV first and then discuss above almost of technical issues and suggest their possible solutions. Even these solutions looks better technologies and if they may increase production cost significantly, we will not prefer to choice that technology since lower cost policy can open the market. Finally I'm trying to suggest how well LED, as future light source, can apply to future LCD TV technologies.