• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 춘계학술발표대회
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• pp.17.1-17.1
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• 2011

Inorganic III-V light emitting diodes (LEDs) have superior characteristics, such as long-term stability, high efficiency, and strong brightness compared to conventional incandescent lamps and OLED. However, due to the brittle property of bulk inorganic semiconductor materials, III-V LED limits its applications in the field of high performance flexible electronics. This seminar introduces the first flexible and implantable GaN LED on plastic substrates that is transferred from bulk GaN on Si substrates. The superb properties of the flexible GaN thin film in terms of its wide band gap and high efficiency enable the dramatic extension of not only consumer electronic applications but also the biosensing scale. The flexible white LEDs are demonstrated for the feasibility of using a white light source for future flexible BLU devices. Finally a water-resist and a biocompatible PTFE-coated flexible LED biosensor can detect PSA at a detection limit of 1 ng/mL. These results show that the nitride-based flexible LED can be used as a type of implantable LED biosensor and as a therapy tool.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.443-445
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• 2008

We have fabricated vertical type organic thin film transistor using $C_{60}$ as a n-type active material to improve the problems of conventional OTFTs. In general, it can be argued that the characteristics of organic transistor were influenced by carrier mobility and density. We have used several kinds of metals as source and gate electrodes to optimize the device characteristics using $C_{60}$. In addition, we have examined the feasibility of fabrication of organic light-emitting transistor (OLET) using MEH-PPV as an emission layer.

• Journal of the Optical Society of Korea
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• 제12권4호
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• pp.326-336
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• 2008

A WDM-PON has been considered as an ultimate solution for access networks. However, there were many technical and practical issues for commercial deployment. These issues were solved with wavelength locked F-P LD and the WDM-PONs employing this optical source were commercialized. These WDM-PON systems have been deployed in Korea, Europe, and US. We reviewed wavelength locking technology and WDM-PON achievements. When we inject spectrum sliced broadband light into an F-P LD, the multimode output is changed to a quasi single mode. Then, we can use the single mode light for WDM signal transmission. The broad spectral gain of the semiconductor gain medium enables a color-free operation of WDM-PON, i.e., an identical ONT can be used for each user. The wavelength locking properties depend on many parameters, especially alignment of injection wavelength to a lasing mode, passband profile of AWG and front facet reflectivity of F-P LD. However, these dependencies can be reduced by proper design of the laser and the injection bandwidth. Thus, WDM-PON systems have been achieved with color-free operation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부A
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• pp.125-127
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• 1998

The widely used power supply (Switched Mode Power Supply : SMPS) as a source in order to stabilize direct current for electronics or communication systems has merits, when it is compared to the existing source for stability, such as high efficiency, small size, light weight by means of switching process of the semiconductor device which controls the flow of power. However, due to existence of inductors and capacitors used for charging energy, the source part in electronic or communication systems hasn't reached the speed, that is supposed to get, for achieving smaller size and lighter weight. In order to got smallness in size, it is necessary to increase switching frequency. And that makes devices for measuring energy smaller. Nevertheless, the rise switching frequency brings increases in switching loss, inductor loss, and power loss. Also, the occurrence of surge and noise caused by high frequency switching is setting higher. The resonant converter has been considered as one of methods that give solutions for the problems of SMPS and that method has been paid attention as a source technology in electronics and communication.

• 반도체디스플레이기술학회지
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• 제15권2호
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• pp.26-31
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• 2016

The Townsend to glow discharge mode transition was investigated in the dielectric barrier discharge (DBD) helium plasma source which was powered by 20 kHz / $4.5 kV_{rms}$ high voltage at atmospheric pressure. The spatial profile of the electric field strength at each modes was measured by using the intensity ratio method of two helium emission lines (667.8 nm ($3^1D{\rightarrow}2^1P$) and 728.1 nm ($3^1S{\rightarrow}2^1P$)) and the Stark effect. ICCD images were analyzed with consideration for the electric field property. The Townsend discharge (TD) mode at the initial stage of breakdown has the light emission region located in the vicinity of the anode. The electric field of the light emitting region is close to the applied field in the system. Immediately, the light emitting region moves to the cathode and the discharge transits to the glow discharge (GD) mode. This mode transition can be understood with the ionization wave propagation. The electric field of the emitting region of GD near cathode is higher than that of TD near anode because of the cathode fall formation. This observation may apply to designing a DBD process system and to analysis of the process treatment results.

• 한국실내디자인학회:학술대회논문집
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• 한국실내디자인학회 2006년도 춘계학술발표대회 논문집
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• pp.189-192
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• 2006

The development of digital technology makes our life more convenient in our lives and its calmness promotes the qualify of our life. Digital-home-automation system lets indoor-living more free, safe and clear so that it really has come true our life style that considers our mind and healthy to be important. Moreover, LED light source that combines the semiconductor with the digital technology has been tried as a current indoor illumination. Also the introduction of the light which has a high technology, like LED light, has been required in living space. It shows that it is very important to have an illuminated- plan which is accepted as well-developed technology. This study deals with the investigation into the user satisfaction of the existing residential area illumination and the investigation into the user satisfaction of the LED illumination being supplied for commercial area now. In the result, the fact is investigated that the user wants the introduction of the digital technology In the illumination because of a backward the residental area illumination in the circumstances being digital gradually. The inconvenience of the illumination used now should be minimized and the development of the LED illumination is a way satisfying the desire. The intended illumination project of the residential area should be accomplished according to the lifestyle of a changing residence.

• 한국실내디자인학회논문집
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• 제14권6호
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• pp.220-227
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• 2005

The development of digital technology makes our life more convenient in our lives and its calmness promotes the qualify of our life. Digital-home-automation system lets indoor-living more free, safe and clear so that it really has come true our life style that considers our mind and healthy to be important. Moreover, LED light source that combines the semiconductor with the digital technology has been tried as a current indoor illumination. Also the Introduction of the light which has a high technology, like LED light, has been required in living space. It shows that it is very important to have an illuminated-plan which is accepted as well-developed technology This study deals with the investigation into the user satisfaction of the existing residential area illumination and the investigation Into the user satisfaction of the LED illumination being supplied for commercial area now. In the result, the fact is investigated that the user wants the introduction of the digital technology in the illumination because of a backward the residental area illumination in the circumstances being digital gradually. The inconvenience of the illumination used now should be minimized and the development of the LED illumination is a way satisfying the desire. The intended illumination project of the residential area should be accomplished according to the lifestyle of a changing residence.

• International Journal of Precision Engineering and Manufacturing
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• 제7권4호
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• pp.14-17
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• 2006

A thin GaN semiconducting film that grows on sapphires due to metalorganic chemical vapor deposition was machined for nanophotonic applications. The thin film had multilayered superlattice structures, including nanoscaled InGaN layers. Eight alternating InGaN/GaN multilayers provided a blue light emission source. Nanoscaled holes, 150 nm in diameter, were patterned on polymethylmethacrylate (PMMA) film using an electron beam lithography system. The PMMA film blocked the etching species. Air holes, 75 nm in diameter, which acted as blue light diffraction sources, were etched on the top GaN layer by an inductively coupled plasma etcher. Hexagonal lattice photonic crystals were fabricated with 230-, 460-, 690-, and 920-nm pitches. The 450-nm wavelength blue light provided the nanodiffraction destructive and constructive interferences phenomena, which were dependent on the pitch of the holes.

• 한국광학회지
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• 제35권3호
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• pp.95-106
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• 2024

일반 백색 LED의 연색성을 보완하기 위해 적색 양자점을 선택적으로 활용함으로써 고연색성 조명을 구현하는 연구가 최근 활발하다. 본 논문에서는 최근 이루어지고 있는 원격 양자점 부품 연구 및 이를 활용한 고연색성 조명 개발의 현황에 대해 소개한다. 특히 양자점 부품이 배치되는 조명의 광구조 최적화에 있어서 중요하게 고려해야 할 다양한 요소를 집중적으로 논의함으로써 향후 고연색성 조명 연구의 방향 및 전망까지 다루고자 했다.

• 전력전자학회논문지
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• 제16권4호
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• pp.358-365
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• 2011

LED는 친환경적 특성, 긴 수명, 우수한 효율 등의 장점이 있어 최근 기존의 백열전등 및 형광등을 대체하는 조명 수단으로 각광받고 있다. 또한, LED는 전기를 빛으로 변환하는 속도가 굉장히 빠른 반도체로 정보의 변조 및 인코딩이 용이하기 때문에 통신 소자로서 활용이 가능하다. 이를 이용하여 기존의 조명 기능을 수행함과 동시에 부가적으로 근거리 무선 통신을 수행하는 것을 가시광 통신 시스템이라 한다. 기존의 전압원 구동 가시광 통신 시스템의 경우, 스위치의 선형 영역 구동으로 인해 전력 변환 효율의 저하 및 발열이 심각하였다. 본 논문에서는 스위치를 스위칭 영역에서 구동시킴으로써 전력 변환 효율과 발열의 획기적인 개선이 가능한 고효율 스위칭 방식의 LED 드라이버를 제안한다. 또한 3MHz 무선 오디오 통신 시스템에 제안된 20W급 LED 드라이버를 적용하여 그 타당성을 검증한다.