• 한국전자통신학회논문지
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• 제10권5호
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• pp.587-592
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• 2015

LED의 사용이 증가됨에 따라, LED 디스플레이의 저전력 설계에 대한 요구가 증가하고 있다. 본 논문에서는 디지털 신호로 제어하는 정전류원 회로에 단열회로 동작을 유도하는 전원소스 공급을 통하여, 저전력화가 가능한 LED 컨트롤러부를 설계하였다. 설계한 회로는 0.35um CMOS Process로 구현하였으며 회로의 선형 동작을 확인하였다. 시뮬레이션 결과 기존의 LED 컨트롤러부에 대비하여 약 82% 소비전력 절감효과를 확인하였다. 본 연구는 LED 디스플레이 동작의 발열 대책 및 저전력화에 유용할 것으로 기대된다.

• Current Optics and Photonics
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• 제3권6호
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• pp.485-495
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• 2019

Photobiomodulation (PBM) using organic light emitting diodes (OLEDs) surface light sources have recently been claimed to be the next generation of PBM light sources. However, the differences between light emitting diodes (LEDs) and OLED mechanisms in vitro and in vivo have not been well studied. In vivo mouse models were used to investigate the effects of OLED irradiation on cellular function and cutaneous wound healing compared to LED irradiation. Mice in the LED- and OLED-irradiated groups were subjected to irradiation with 6 J/㎠ LED and OLED (630 nm), respectively, for 14 days after wounding, and some mice were sacrificed for the experiments on days 3, 7, 10, and 14. To evaluate wound healing, we performed hematoxylin-eosin and Masson's trichrome staining and quantified collagen density by computerized image analysis. The results showed that the size of the wound, collagen density, neo-epidermis thickness, number of new blood vessels, and number of fibroblasts and neutrophils was significantly influenced by LED and OLED irradiation. The tissue levels of interleukin (IL)-β, IL-6 and tumor necrosis factor (TNF)-α were investigated by immunohistochemical staining. LED and OLED irradiation resulted in a significant increase in the tissue IL-β and IL-6 levels at the early stage of wound healing (P < 0.01), and a decrease in the tissue TNF-α level at all stages of wound healing (P < 0.05), compared to the no-treatment group. The expression levels of the genes encoding vascular endothelial growth factor and transforming growth factor-beta 1 were significantly increased in LED and OLED-irradiated wound tissue at the early stage of wound healing (P < 0.01) compared to the no-treatment group. Thus, OLED as well as LED irradiation accelerated wound healing by modulating the synthesis of anti-inflammatory cytokines and the expression levels of genes encoding growth factors, promoting collagen regeneration and reducing scarring. In conclusion, this suggests the possibility of OLED as a new light source to overcome the limitations of existing PBMs.

• 패션비즈니스
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• 제25권1호
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• pp.51-64
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• 2021

The purpose of this study was to develop smart bags that combining fashion-specific trends and smart information technologies such as light-emitting diodes(LED) and optic fibers by grafting marquage techniques that have recently become popular as part of eco-fashion. We applied e-textiles by designing leather tote bags that could show off LED luminescence. A total of two tote bags, a white-colored peacock design and a black-colored paisley design, divided the LED's light-emitting method into two types, incremental lighting and random light-emission to suit each design, and the locations of the optical fibers were also reversed depending upon the design. The production of circuits for the LEDs and optical fibers was based on the design, and a flexible conductive fabric was laser-cut instead of wire line and attached to the circuit-line location. A separate connector was underwent three-dimensional(3D)-modeling and was connected to high-luminosity LEDs and optic fiber bundles. The optical fiber logo part expressed a subtle image using a white-colored LED, which did not offset the LED's sharp luminous effects, suggesting that using LEDs with fiber optics allowed for the expression of each in harmony without being heterogeneous. Overall, the LEDs and fiber optic fabric were well-harmonized in the fashion bag using marquage techniques, and there was no sense of it being a mechanical device. Also, the circuit part was made of conductive fabric, which is an e-textile product that feels the same as a thin, flexible fabric. The study confirmed that the bag was developed as a smart wearable product that could be used in everyday life.

• 한국전기전자재료학회논문지
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• 제18권10호
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• pp.945-949
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• 2005

We have grown GaN layers with in-situ SiN mask by metal organic chemical vapor deposition (MOCVD) and study the physical properties of the GaN layer. We have also fabricate PN junction light emitting diode (LED) to investigate the effect of the SiN mask on its optical property By inserting a SiN mask, (102) the full width at half maximum (FWHM) decreased from 480 arcsec to 409 arcsec and threading dislocation (TD) density decreased from $3.21{\times}10^9\;cm^{-2}$ to $9.7{\times}10^8\;cm^{-2}$. The output power of the LED with a SiN mask increased from 198 mcd to 392 mcd at 20 mA. We have thus shown that the SiN mask improved significantly the physical and optical properties of the GaN layer.

• 한국진공학회지
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• 제17권3호
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• pp.211-214
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• 2008

Metal organic chemical vapor deposition (MOCVD)를 이용하여 사파이어 기판 위에 405 nm의 파장을 갖는 GaN light-emitting diode (LED)를 제작하였다. LED의 InGaN 활성층에서 생성되어 칩의 후면으로 향하는 광자를 전면으로 반사시키기 위하여, 사파이어 기판 후면에 반사막을 증착하였다. 반사막으로는 Al을 사용하였으며, 사파이어 기판에 대한 Al 박막의 접착력을 개선하기 위하여 사파이어 기판 후면에 Ti를 먼저 증착한 후에 Al을 증착하였다. Ti-Al 반사막을 채용한 결과, 광추출 효율이 52 % 향상되었다.

• 패션비즈니스
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• 제23권1호
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• pp.103-115
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• 2019

In this study, we provided examples of light emitting diodes (LEDS) in everyday sportswear and confirmed their usefulness to provide functionality, aesthetics, and entertainment. One type of sports jacket and one set of sportswear were designed and manufactured using LEDs and made available to the general public for use in daily life to provide functionality, aesthetics, and entertainment. To generate digital images, a textural design of a circuit image was developed and applied, and the LEDs were placed on the developed textile in an attempt to merge the LEDs with the design. The product was equipped with a tilt sensor and produced a randomly lighted jacket with LEDs that adjusted according to movement. The LEDs turned on in the desired location by lifting the arm during night sports activities. The tricolor of NEO PIXEL LEDs lit randomly and its rhythmical design could be maximized when moving or exercising outdoors, and also for entertainment. The role of creating interest for lively and unexpected pleasures and the aesthetic beauty of LED lights were also obtained. There was no inconvenience or restriction of movement by LEDs or internal structures using the hot-melting technique, and the removable attachment of the device made it easier to wash.

• 반도체디스플레이기술학회지
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• 제22권2호
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• pp.1-5
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• 2023

In the past, display devices have undergone many changes, such as plasma TVs and LCDs, and have continued to develop. Recently, new display technologies, such as Organic Light Emitting Diode displays and Inorganic Light Emitting Diode displays, have been developed. Among them, Micro LED displays have the potential to improve performance more than LCDs and OLEDs, but a lot of effort and time are needed until the mass production technology (transfer and bonding) of Micro LED displays is developed. We have developed a new Micro LED display light source that can be produced using existing transfer and bonding process technologies to enable faster commercialization of Micro LED in the industry. This light source is TFT deposition on LED. TFT deposition on LED has the advantage of being able to produce displays using existing process technology, making early commercialization of display application products possible. In this study, we applied the Active Driving method to verify the performance of TFT deposition on LED as a display to determine its commercialization potential. Additionally, to facilitate faster application of Micro LED in the industry, we applied TFT deposition on LED to Optical Wireless Communication systems, which are widely used in application service areas such as safety/security and sensors, to verify its communication performance. The experimental results confirmed that TFT deposition on LED is not only capable of AM driving but can also be applied to OWC systems.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.97-97
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• 2010

We demonstrate the hybrid polymer-quantum dot based multi-functional device (Organic bistable devices, Light-emitting diode, and Photovoltaic cell) with a single active-layer structure consisting of CdSe/ZnS semiconductor quantum-dots (QDs) dispersed in a poly N-vinylcarbazole (PVK) and 1,3,5-tirs- (N-phenylbenzimidazol-2-yl) benzene (TPBi) fabricated on indium-tin-oxide (ITO)/glass substrate by using a simple spin coating technique. The multi-functionality of the device as Organic bistable device (OBD), Light Emitting Diode (LED), and Photovoltaic cell can be successfully achieved by adding an electron transport layer (ETL) TPBi to OBD for attaining the functions of LED and Photovoltaic cell in which the lowest unoccupied molecular orbital (LUMO) level of TPBi is positioned at the energy level between the conduction band of CdSe/ZnS and LiF/Al electrode (band-gap engineering). Through transmission electron microscopy (TEM) study, the active layer of the device has a p-i-n structure of a consolidated core-shell structure in which semiconductor QDs are uniformly and isotropically adsorbed on the surface of a p-type polymer core and the n-type small molecular organic materials surround the semiconductor QDs.

• 한국유기농업학회지
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• 제26권3호
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• pp.515-532
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• 2018

Light is an essential and powerful element to animals. A light-emitting diode (LED) is most efficient in terms of economic benefits. The aim of the present study was to evaluate the effects of LED lighting time on milk production, milk composition, and the immune response of Holstein cows. Forty lactating cows were assigned to four experimental groups: control; natural daylight, treatment; am3-6, pm6-12 and pm6-am6. We found that there was no significant effect on the decrease ratio in milk production among the groups. Milk urea nitrogen (MUN) was significantly decreased in pm6-am6 and pm6-12 than the control. With regard to the hemolytic biochemical analysis, GLU was significantly increased and CRE, T-BIL were significantly decreased in the pm6-12 than the control. IGF-1 levels were significantly increased in pm6-12 compared to other groups. Besides, cortisol was significantly lowered in the pm6-12 than the control, while prolactin, IgA and IgG were not significant among the groups. In addition, catalase and glutathione peroxidase were also significantly increased in pm6-12 than the control. However, antioxidant enzyme activity and superoxide dismutase were not significant among the experimental groups. Therefore, it was concluded that LED lighting time had some impact on blood parameters and immune responses in dairy cows without any changes in milk production.

• 한국의상디자인학회지
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• 제21권1호
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• pp.103-113
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• 2019

The purpose of this study was to develop an e-textile using LEDs that can enhance visual and functional effects, and to identify their applicability to sportswear. By applying the design elements of fashion design concretely with LEDs, an e-textile design module is developed and that module is applied to the product, so LED application design can be proposed for use in a practical product. E-textiles have been divided into five categories, and their usefulness were verified by applying e-textiles to men's and women's sportswear. The product beign considered has a built-in tilt sensor, which illuminates the LEDs according to the user's movements, and allows the LEDs to be turned on or off in accordance to the user's preference. E-tatoo is a type of LED application that enhances the appearance by placing LEDs on a small area, emphasizing origin points, just like an actual tattoo. Designed with LEDs arranged in a straight line and various curved forms, e-strips can provide a function that matches the characteristics of each section of clothing or fashion item. E-wappen uses about 7-10 LEDs to give motifs a strong sense of visibility, thus adding to their vibrancy. E-panels and e-clothes were able to produce creative and high-value textures. It is also expected to be used for special purposes or bags as it is possible to produce high value-added textures that are creative and aesthetically beautiful. For instance, a progressive LED string on the straight line of female leggings can further emphasize rhythmic movements during exercise, and e-wappen also serves the purpose of nighttime protection. It is also believed that the application of dance or dance-related sportswear will make the movement of the performance more intense and lively.