• Journal of KIISE
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• v.43 no.11
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• pp.1298-1306
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• 2016

Backlight has a major factor in power consumption of TFT-LCDs which are most popular in portable devices. There have been a lot of attempts to achieve power savings by backlight dimming. At the same time, the researches have shown image compensation due to decreased brightness of a displayed image. However, existing image compensation methods such as histogram equalization have some limits in completely satisfying the human visual system (HVS)-awareness. This paper proposes an enhanced dimming technique to obtain both power saving and HVS-awareness by combining pixel compensation and histogram specification for TFT-LCDs. This method executes a search algorithm and an automation algorithm employing simplified calculations for fast image processing. Experimental results showed that the proposed method achieved significant improvement in visual satisfaction per power saving over existing backlight dimming.

• Polymer(Korea)
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• v.33 no.5
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• pp.413-419
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• 2009

As the refractive index of the prism layer becomes higher, the optical performance of the prism sheet gets better and the efficiency of the LCD backlight unit is improved. In order to increase the refractive index of the prism layer, the ultraviolet curing type resins were prepared by mixing high refractive index materials containing aromatic groups and the multi-functional reactive diluents. By using 9,9-bis [4-(2-acryloyloxyethoxy)phenyl] fluorene, the refractive index of the prism layer was increased up to 1.58 and the brightness of the backlight unit was improved. Since the light source used in the backlight unit caused the yellowing in the prism sheet and deteriorated the brightness accordingly, the hindered amine light stabilizer was used to improve the yellowing resistance successfully.

• 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.

• Journal of the Korean association of regional geographers
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• v.23 no.2
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• pp.366-375
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• 2017

Researching Stromatolites spread all over Gyeong-San, province Gyeongsangbukdo, it raise an objection for preservation of original state caused by natural weathering, artificial destruction, illegal emission and enviromental pollution. Stromatolites in Gyeong-San was formed on lake Meszoic era cretaceous. So it is representative rock of geological feature of sediment formed in water and landscape. It could be used as educational data on mesozoic stratum and earth surface, and resources of observation and experience program. It could apply as educational venue place in terms of Mesozoic era cretaceous motif. And it is managed various programs appling 4H (Healing, Hiking, Hand, History) experience program based on local community. And it is concerned software program introducing augumented reality, furthermore discuss with related field.

• 전자공학회논문지 IE
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• v.46 no.4
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• pp.57-65
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• 2009

This paper presents the image contrast enhancement technique suitable for local dimming backlight of small-sized mobile display while achieving the reduction of the power consumption. In addition to the large-sized TFT-LCD, small-sized one has adopted LED for backlight. Since, conventionally, LED was mounted on the side edge of a display panel, global dimming method has been widely used. However, recently, new advanced method of local dimming by placing the LED to the backside of the display panel and it raised the necessity of sub-blocked processing after partitioning the target image. When the sub-blocked image has low brightness, the supply current of a backlight LED is reduced, which gives both enhancement of contrast ratio and power consumption reduction. In this paper, we propose simple and improved image enhancement algorithm suitable for the small-sized mobile display. After partitioning the input image by equal sized blocks and analyzing the pixel information in each block, we realize the primary contrast enhancement by independently processing the sub-blocks using the information such as histogram, mean, and standard deviation values of luminance(Y) component. And then resulting information is transferred to each backlight control unit for local dimming to realize the secondary contrast enhancement as well as reduction of power consumption.

• Proceedings of the Korean Vacuum Society Conference
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• 2005.02a
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• pp.73-73
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• 2005

• Proceedings of the Korean Vacuum Society Conference
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• 2006.02a
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• pp.102-102
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• 2006

• Korean Journal of Optics and Photonics
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• v.28 no.6
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• pp.314-326
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• 2017

The display, which is closely related to modern life, is being developed as a window on a network connecting individuals, devices, and even other individuals from simple display devices, as the IT industry develops. To achieve a thinner, brighter unit with less consumption for backlighting, the LED light source has applied, and the study of complex light-guiding plates to improve luminance, uniformity, and viewing angle has been initiated. In this paper, we summarize the research results for the scatterers' pattern formation of the light-guiding plate and the arrangement and composition of the light source, which have enabled remarkable development of the LED backlight unit over the last 10 years. In addition, a large-area flat-screen illumination system, applying the light-guiding-plate technology to a currently noteworthy LED light-fixture design, is outlined. Finally, we discuss the direction and way to develop the current technology more progressively.

• Korean Journal of Optics and Photonics
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• v.22 no.6
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• pp.247-255
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• 2011

The optical performance of LLF(Lenticular Lens Film)-based backlight was studied by using optical simulation as functions of the aspect ratio and the refractive index of lenticular lenses. In order to perform reliable simulation, the BSDF(bi-directional scattering distribution function) of the scattering dots on the bottom surface of the light guide plate was obtained as a superposition of the Lambertian and the elliptic Gaussian distribution components by comparing the experimental results and the simulation for the luminance distribution on the light guide. Based on this approach, an appropriate BSDF of the scattering dots of the light guide was constructed. The resultant values of the optimized aspect ratio and the refractive were found to be 1.25 and 1.65, respectively. In spite of the hybrid aspects of LLF incorporating both diffusing and collimating functions, the optical performance, in particular the on-axis luminance of LLF-based backlight was inferior by about 20% compared to that of conventional backlights adopting one prism film. However, the combination of two lenticular lens films resulted in comparable luminance gain as well as smooth decrease in the luminance with the viewing angle without exhibiting any side lobes.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.05a
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• pp.161-164
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• 2004

본 연구에서는 고휘도 백라이트에 있어서 일반적으로 휘도 향상을 위해서 사용하는 프리즘 혹은 편광프리즘 등의 고가의 기능성 광학시트를 사용하지 않고, 확산시트만을 사용하여 고성능의 BLU 를 제조할 수 있는 핵심부품으로서 프리즘 도광판에 대해서 연구하였다. 고휘도 프리즘 도광판을 구현하는 방법으로 먼저, 광학적으로 시뮬레이션을 통해서 가능성을 검증하고, 기본적인 광학구조의 설계를 수행한 후, 이를 stamper 방식의 사출성형으로 실물을 구현하여 설계의 재현성을 확인하는데 역정을 두었다. 실험결과, 17 inch, 두께 8 mm 사양의 모니터용 도광판에 있어서, 고휘도 BLU를 구현하기 위해서 도광판 밑면과 윗면에 프리즘 구조를 부가한 도광판의 경우에 기존의 인쇄형 도광판보다 약 20%의 휘도향상 효과를 확인할 수 있었으며, 향후 확산시트만을 사용한 고휘도 백라이트로의 응용가능성을 검증할 수 있었다.