• 한국실내디자인학회논문집
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• 제23권6호
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• pp.78-86
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• 2014

Lighting in indoor space is being changed to system lighting converged with IT technology. Office space lighting with incandescent lamps and fluorescent lamps was completed through overall lighting plan by illumination in most cases, but convergence between LED lighting and IT technology enables the technology of responding to user requirements to be realized. Optical physical quantity suitable for humans and the lighting environment in accordance with user's sensibility, based on space function and user's behavior, would contribute to the improvement of service productivity, energy reduction, and enhancement of emotional satisfaction by providing user optimized lighting solution. Thus, user-customized system lighting guidelines to be applied with integration indicators of optics and sensibility are required. For the design elements required by users, environmental factors, product characteristics, optical characteristics, and sensibility factors are drawn from the design cases for office space and the survey, and the design check list and evaluation indicators are considered to reflect the requirements in the design and requirement indicators to give integrated satisfaction for optics and sensibility are developed. Purpose-centered design method from the user's viewpoint is applied to function-focused design through scenario, and it should be applied flexibly, as the new lightning design method solutions, to the concept design stage of space lighting design and device development. This paper, therefore, presents user-customized guidelines by pursuing the optics and sensibility evaluation and design method combining the requirement conditions and scenario, to be used for lighting content development and design.

• 한국ITS학회 논문지
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• 제9권2호
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• pp.60-67
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• 2010

최근에, LED를 사용한 WPAN 응용 기술에 많은 연구가 진행되고 있다. 하지만, LED를 이용한 가시광 통신은 통신을 수행하는데 약점을 가지고 있다. 시스템 성능을 저하시키는 요인으로 통신 환경에서 다른 물체에 의한 전파 지연으로 발생하는 다중 경로 페이딩을 들 수 있다. 따라서 본 논문에서 OFDM 기술은 다중 경로 페이딩과 분산을 줄이고, 고속 데이터 전송을 제공하기 위해서 적용하였다. 게다가, 광잡음에 의한 정보 손실을 줄이기 위해서 채널코딩으로써 터보 부호화 기술을 사용하였다. OFDM과 터보 부호화를 적용하므로써, 약 4 [dB] 정도의 성능향상을 보임을 알 수 있었다. 또한, 도플러 효과가 일어난다고 가정하였을 경우, 시스템 성능이 저하됨을 시뮬레이션을 통해 알 수 있었다.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 춘계학술대회 논문집
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• pp.141-144
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• 2007

BLUs are major component in LCD industry which occupies 90% or more of FPD market worldwide and BLU market is expected to be expanded continuously according to the trend of miniaturization, slimness, low power consumption and low weight. The larger the BLU market scale, the more important standardization of performance evaluation techniques to clearly prescribe the product specification. Currently the government is promoting the establishment of related laws and coincidence with international standards to cope with agreements such as WTO/TBT, but the nongovernmental standardization activities are not enough to be actualized. Furthermore, BLU related components such as CCFL, EEFL, inverter and reflector are already developed for localization to substitute imports with home products but collective standardization, national standardization, and international standardization are still not done. So, performance specifications and evaluation methods for normal fluorescent lamps or industrial lamps are being adopted and used as national standards and safety certification standards instead. Making these standards enables to prepare a chance to penetrate into global market and to promote world best products. Also, by making this collective standard, it provides chances to take part in international standardization activities, to protect domestic industries and technologies, to obtain the trend of advanced technologies, and to be predominant over other countries. That is to say, CCFL standardization helps raise 21st century national strategic technology policy and go ahead of globalization of core technologies.

• 전력전자학회논문지
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• 제19권1호
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• pp.91-97
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• 2014

Recently, the LED(Light Emitting Diode) is expected to replace conventional lamps including incandescent, halogen and fluorescent lamps for some general illumination application, due to some obvious features such as high luminous efficiency, safety, long life, environment-friendly characteristics and so on. To drive the LED, a single stage PFC(Power Factor Correction) flyback converter has been adopted to satisfy the isolation, PFC and low cost. The conventional flyback LED driver has the serious disadvantage of high 120Hz output current ripple caused by the PFC operation. To overcome this drawback, a new PFC flyback with low 120Hz output current ripple is proposed in this paper. It is composed of 2 power stages, the DCM(Discontinuous Conduction Mode) flyback converter for PFC and BCM(Boundary Conduction Mode) boost converter for tightly regulated LED current. Since the link capacitor is located in the secondary side, its voltage stress is small. Moreover, since the driver is composed of 2 power stages, small output filter and link capacitor can be used. Especially, since the flyback is operated at DCM, the PFC can be automatically obtained and thus, an additional PFC IC is not necessary. Therefore, only one control IC for BCM boost converter is required. To confirm the validity of the proposed converter, theoretical analysis and experimental results from a prototype of 24W LED driver are presented.

• 박물관보존과학
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• 제18권
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• pp.65-76
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• 2017

기술의 발달과 친환경 에너지 필요성 증가로 인하여 박물관의 조명은 퇴색방지 형광등과 할로겐 등에서 LED 등으로 교체되고 있다. 본 논문에서는 LED 조명뿐 아니라 향후 박물관에 도입될 다양한 조명 검토 기준 설정에 관한 연구를 진행하였다. LED는 기존 알려진 것처럼 자외선은 거의 방출되지 않았으나 가시광선으로도 적산조도에 따라 변색이 발생하는 것이 확인되었다. 또한 전구색이라는 색온도 2800K의 LED와 백색의 색온도 5500K LED의 변색을 비교 실험하였다. 분광분포 스펙트럼에서 확인 결과 LED는 색온도가 높을수록 블루스파이크가 증가하는데 이에 따라 변색도 더 많이 발생함이 확인되었다. 따라서 앞으로 박물관에서 조명 환경 기준에 대하여 기존 조도와 더불어 색온도 등을 분광분포 스펙트럼을 활용하여 같이 검토할 필요가 있다.

• 한국산학기술학회논문지
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• 제20권1호
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• pp.170-178
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• 2019

최근 에너지 절감에 대한 관심도가 높아짐에 따라 에너지 소비가 높은 형광등과 백열등을 대체하는 친환경소재인 LED의 조명을 활용하는 움직임이 활발하다. 그러나, 고출력 LED의 경우 발열에 의한 열화현상 때문에 수명이 단축되는 현상이 발생하게 된다. 이에 대한, 해결방안으로 본 논문은 LED Packing중 방열판표면의 거칠기 처리를 통하여 열전달 계수를 증대시킴으로서 LED 수명연장 효과를 평가하였다. 거칠기 공정은 사포 및 샌드블라스트를 이용하여 진행하였다. 각 표면처리 공정에 따른 거칠기 및 표면적 변화를 정량적으로 평가하였으며, 열전달 계수를 측정하였다. 샌드블라스트, 사포를 이용하여 알루미늄 표면에 거칠기처리를 진행했을 경우 미 처리 시 보다 높은 대류 열전달 계수를 얻을 수 있었고, 샌드블라스트 처리 시 약 82.76%의 높은 방열 효율 향상을 얻을 수 있어, 이를 방열판에 적용할 시 큰 경제적 부담 없이 기존대비 더 높은 방열효율 증대를 통해 LED 수명을 대폭 연장 시킬 것으로 기대된다.

• 한국전기전자재료학회논문지
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• 제37권5호
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• pp.486-493
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• 2024

Lighting has been used for a long time as a medium to convey brightness from darkness, and through incandescent lamps and fluorescent lamps, LED light sources have now become the standard in the lighting industry. Recently, the lighting equipment industry has been undergoing rapid digital transformation, starting with smart lighting, and is evolving into smart lighting customized for individuals and spaces through the development of IoT technology, cloud-based services, and data analysis. However, the blue light emitted from digital devices (computers, smartphones, tablets, etc.) or LED lights stimulates the melanopsin in the optic ganglion cells in the retina of the eye, which in turn stimulates the secretion of melatonin through the pineal gland, which regulates the secretion of melatonin. This can reduce sleep quality or disrupt biological rhythms. This interaction between blue light and melatonin has such a significant impact on human sleep patterns and overall health that it is essential to reduce exposure to blue light, especially in the evening. Human-centered lighting refers to lighting that takes into account the effects of light on the physical and mental areas, such as human activity and awakening, improvement of sleep quality, and health management. Many research institutes study the effects in the visible area and the non-visible area. By studying the impact, it is expected to improve the quality of human life. In this study, we plan to study ways to implement human-centered lighting by collecting sunrise and sunset data and linking commercialized LED packages and control devices with open-source hardware.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.1058-1061
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• 2004

Recently, According to companies of TFT LCD are making large sized products more and more. In the vortex of Products with a monitor and LCD TV is applied in a technique of a high viewing angle(FFS, IPS, VA). Also, as a high luminance, high speed response time, high degree of a color purity, and so on are continuing to develop a high performance, it is necessary to improve a specific character of high luminance that apply to LCD TV as a LCD BLU. Because a LCD panel for TV usually has a lower resolution that compare to a monitor, the structure of present backlight system can't put out its power even though it has a merit in transmission. Therefore, the examination of improvement about the high luminance direct typed BLU for LCD TV that presupposes several uses of CCFL(Cold Cathode Fluorescent Lamp) or EEFL(External Electrode Fluorescent Lamp)is actively being progressed. Although it is necessary to increase the number of lamps for applying high performance by the direct type, in this case, because we can design the character of luminance for adoption of high performance. We can satisfy with a level of luminance for LCD TV. Accordingly, we analyzed a change of the number of CCFL, mechanical and optical character to produce the direct typed backlight in 32inches spec. Consequently, we achieved luminance of 6597nit,which was including polarization film, and secured the standard for LCD TV.

• 원예과학기술지
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• 제31권4호
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• pp.400-406
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• 2013

This study was conducted to investigate the growth and flowering of African marigold (Tagetes erecta L.) and salvia (Salvia splendens F. Sello ex Ruem & Schult.) seedlings before and after storage under fluorescent lamps and green LED radiation conditions with different light intensities during storage. The both seedlings were kept under a storage room controlled at $8^{\circ}C$ air temperature and $40{\pm}10%$ relative humidity conditions. Light intensities were maintained at 15 and $30{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ during storage. In lighting treatments, dry weight of African marigold at 28 days after storage was not significantly different, and decreased approximately 29% compared to pre-storage under dark treatment. There was no significant difference in the leaf area of salvia seedlings stored under dark condition compared to before storage, but the leaf area under green light radiation with higher light intensity (treatment GH) was two times greater than before storage. The survival rate after transplanting of African marigold stored under dark condition was 10%, and days to flowering increased compared to those stored under fluorescent and green light with higher light intensity (treatment FLH, GH). Comparing to before storage, growth and flowering of the both seedlings after storage were significantly promoted by the light exposure during storage. The present experimental results show that the light intensity should be decided to maintain minimum growth during lighting storage and storage quality of the seedlings such as flowering promotion and extended blooming period after lighting treatment during storage period from the above results.

• 생물환경조절학회지
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• 제7권1호
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• pp.35-41
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• 1998

완전제어형 식물공장하에서 인공광원에 따른 결구상추의 생육, 잎끝마름증과 배양액속의 무기이온 변화를 검토하고자 본 실험을 수행하였다. 인공광원에 따른 지상부 생체중과 건물중간의 유의적인 차이는 없었으나 전반적인 생육은 형광등에서 가장 낮게 나타났다. 인공광원중 생육과 램프의 경제성을 고려해 볼때, 고압나트륨등을 사용하는 것이 좋을 것으로 생각된다. 인공광원에 따른 잎끝마름증 발생시기는 정식 후 14일에 처음 발생하였으며, 발생부위는 자엽으로 부터 9∼10번째 잎이었다. 발생원인으로는 빠른 생장율과 상추의 칼륨흡수로 추정되었다. 그리고 인공광원에 따라 배양액속의 무기 성분 변화를 보면, 세처리구 모두 칼슘. 마그네슘, 구리와 아연 함량 등은 축적되는 경향을 보였으며, 전질소, 인, 철과 망간 함량등은 안정적이었다.