• 전기학회논문지
• /
• 제57권5호
• /
• pp.833-838
• /
• 2008

Generally Lighting system consists of lamp and luminaire. When a fluorescent lamp is installed in luminaire, power and light output is changed by ambient temperature. Particularly electrodeless lamp depends on the changes that are mercury pressure with amalgam temperature and magnetic properties with ferrite temperature. It has finally influence on optical efficiency. In this study, the temperature change of ferrite and cold spot, vessel are measured at transitional state and then same characteristics are measured with increase of ambient temperature. At transitional state, luminous flux is related to temperature change of cold spot that compare with behavior of mercury pressure and light output. At increase of ambient temperature, we analyzed change that efficiency and electrical, optical characteristics of elecrodeless lamp are related to ferrite core and cold spot temperature. Additionally, spectrum, color temperature and coordination are measured to check that is relation with ambient temperature.

• 수산해양기술연구
• /
• 제51권2호
• /
• pp.163-170
• /
• 2015

Recently LED fish-attracting lamps have been more widely used in fisheries as low-cost and high-efficiency fishing gear, and development of long-life high-efficiency lamps is required through the design of LED packages to optimize heat resistance. This study developed an improved LED fish-attracting lamp with excellent heat performance, which was verified using a numerical model. Heat-resistance design factors such as the heat-radiation fin shape, PCB type, and LED chip count were investigated and optimized. Comparison with a commercial 180-W LED fishing lamp showed that the increase in initial temperature was 40% higher than that of the surrounding LED chip because of design errors in contact thermal resistance. The 250-W LED lamp developed in this study has a characteristic with thermal rising in linearly stable according to the heat source. In addition, luminance efficiency was improved by 20-65% by using flow-visualization simulation. A decrease of 45% in total power consumption with a fuel-cost reduction of over 55% can be expected when using these optimized heat release design factors.

• Bulletin of the Korean Chemical Society
• /
• 제34권1호
• /
• pp.107-111
• /
• 2013

A new green-emitting material with donor-acceptor architecture, 3,7-bis(1'-phenylbenzimidazole-2'-yl)-10-phenylphenothiazine (BBPP) was synthesized and its thermal, optical, and electroluminescent characteristics were investigated. Organic light-emitting diodes (OLEDs) with four different multilayer structures were prepared using BBPP as an emitting layer. The optimized device with the structure of [ITO/2-TNATA (40 nm)/BBPP (30 nm)/TPBi (30 nm)/Alq3 (10 nm)/LiF (1 nm)/Al (100 nm)] exhibited efficient green emission. Enhanced charge carrier balance and electron mobility in the organic layers enabled the device to demonstrate a maximum luminance of 31,300 cd/$m^2$, a luminous efficiency of 6.83 cd/A, and an external quantum efficiency of 1.62% with the CIE 1931 chromaticity coordinates of (0.21, 0.53) at a current density of 100 mA/$cm^2$.

• 정보저장시스템학회논문집
• /
• 제9권1호
• /
• pp.10-16
• /
• 2013

Through the rapid development of LED TV, a large-area edge-lit backlight unit is widely researched in the display industry for enhancing the optical efficiency, luminous uniformity and slim design. In addition, an edge-lit backlight unit includes many optical sheets such as reflection sheet, prism sheet and diffuser sheet. However the function can be replaced by the carefully patterned light guide plate (LGP). Micro patterns which located on the top and bottom surface of light guide plate was designed by ray-tracing optical simulation. The designed patterns improved the light characteristics of LGP, including optical extraction efficiency and intensity distribution uniformity. These results suggest that it is very effective method to design edge-lit LGP with micro-patterns on both sides for large-area display and to reduce the fabrication cost.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
• /
• pp.392-393
• /
• 2007

In this paper, we report the characteristics inorganic EL device with high dielectric constant materials of PMN, PZT. Fabricated EL device shows stable light emission even at 20kHz -400Volt without any break down failure. Brightness voltage curve of EL device is same with typical EL. As increasing applied voltage, the brightness increased linearly. From the results of Frequency and duty ratio variation, over 50% of brightness increment was seen. Luminous efficiency was increased upto 200V range and saturated over 200V by slow increasement of light emission. We got e bright stable emission of 1733 cd/m2 at the condition of Frequency 35 KHz, Duty 10%, 400V.

• KIEAE Journal
• /
• 제7권6호
• /
• pp.29-36
• /
• 2007

Recently, rapid development of technique and change of lifestyle during nighttime has activated the urban outdoor lighting and renovated consideration of nightscape. As the interest of nightscape increases more widely, outdoor lighting has been installed more and more in the cities. Nightscape comes in diverse forms. So, there is no absolute standard for outdoor lighting. But only bright outdoor lighting is not necessarily a good nightscape. Installation lighting without master plan or excessive outdoor lighting may cause a inharmony. This study aims to analyze the luminous characteristics of facade in shopping complexes. For the purpose, four large-scale shopping complexes located in Dongdaemun area were selected. Building facade composition, outdoor lighting composition, and lighting equipment of each shopping complexes are surveyed, and luminance of building facade were measured with Prometric 1400. The result of the study are as follows; (1) Horizontally large-scale shopping complexes emphasize the building entrance and shape of the building at night by outdoor lighting. (2) Non cut-off luminaries installed in building entrance and shop front caused the potential of light pollution.

• 융합신호처리학회논문지
• /
• 제23권2호
• /
• pp.50-61
• /
• 2022

This work demonstrates the design and evaluation of Aqua-Aware, a lightweight miniaturized light emitting diode (LED) based underwater compact sensor node which is used to obtain different characteristics of the underwater environment. Two optical sensor nodes have been designed, developed, and evaluated for a short and medium link range called as Aqua-Aware short range (AASR) and Aqua-Aware medium range (AAMR), respectively. The hardware and software implementation of proposed sensor node, algorithms, and trade-offs have been discussed in this paper. The underwater environment is emulated by introducing different turbulence effects such as air bubbles, waves and turbidity in a 4-m water tank. In clear water, the Aqua-Aware achieved a data rate of 0.2 Mbps at communication link up to 2-m. The Aqua-Aware was able to achieve 0.2 Mbps in a turbid water of 64 NTU in the presence of moderate water waves and air bubbles within the communication link range of 1.7-m. We have evaluated the luminous intensity, packet success rate and bit error rate performance of the proposed system obtained by varying the various medium characteristics.

• 한국산학기술학회논문지
• /
• 제11권3호
• /
• pp.827-834
• /
• 2010

발광층에 도펀트가 도핑된 다층 유기발광다이오드 소자 구조에서의 발광 메카니즘을 검증하기 위해 전기적인 특성요인들을 수치해석 하였다. 본 논문에 적용한 유기발광다이오드 소자는 ITO/NPB/$Alq_3$:C545T(%)/$Alq_3$/LiF/Al으로 이루어져 있으며 도펀트인 C545T의 도핑 농도를 변화시킨 4종류의 소자 구조에 대해 특성 변화를 검토하였다. 그 결과 도펀트의 도핑 농도 변화에 따라서 전압-전류 특성이 변화되어짐을 확인하였고, 이는 참고 문헌에 제시되어 있는 전압-전류밀도 실험 데이터와 매우 잘 일치되었다. 또한 도펀트를 도핑시킨 소자 구조들에서 전압-휘도 특성이 대폭 향상되어 발광효율이 3배정도 향상되었다. 이와 같은 guest-host system이 적용된 유기발광다이오드 소자의 동작 메카니즘을 분석하기 위하여 소자 내부에서의 전계분포, 전하분포, 재결합율 등의 전기적인 항목들에 대한 특성의 변화를 관찰하였다.

• 한국인터넷방송통신학회논문지
• /
• 제22권2호
• /
• pp.15-20
• /
• 2022

색채는 크게 세 가지 속성인 색상, 명도, 채도로 구성되어 있으나 색채를 시감적으로 인지하는데 있어서 각 속성을 구분하여 독립적으로 인지하지 않는다. 채도와 밝기 관련 기존 선행된 연구들은 채도 속성의 순도 정도에 따라 밝기 속성이 다르게 느껴진다는 결과를 유의미하게 얻을 수 있었으나 정신물리학적 실험 대부분이 감산 혼합을 활용한 사례이기에 디스플레이 기반의 색채 인지 기초 연구가 필요하다. 본 연구에서는 자체 발광 시스템을 보유한 디스플레이 기반에서 채도와 밝기 관련 시각적 특성을 알아보고자 정신물리학적 실험을 진행하고 이를 분석하였다. 가산 혼합 형태의 디스플레이에서 일정한 밝기를 선정한 후 주요 색상의 채도를 조정하여 실험을 진행하였다. 본 연구에서는 진행된 실험 결과를 분석하여 감산 혼합과 동일한 결과가 산출되는지 알아보고 색채 인지 특성에 대한 연구 자료로써 유의미 여부를 정의한 후 향후 연구방향을 제시한다.

• 조명전기설비학회논문지
• /
• 제22권4호
• /
• pp.107-113
• /
• 2008

본 실험은 구동 온도와 방전관의 길이에 따라 변화하는 ICP 광원의 전기 광학적 특성에 대해서 알아보았다. 광원의 전기 광학적 특성이 정상상태에 놓이는 구동 조건을 확인하기 위하여 시간에 따른 전력 소모와 광속의 변화를 측정하였다. 전력소모와 광속의 시간에 따른 변화를 측정한 결과를 통해서 볼 때 최초구동에서 70분이 경과한 이후부터 전력소모는 초기값에 대해 1.45[%], 광속은 0.36[%]의 안정성을 나타냈다. 항온챔버 내에서 온도를 5구간으로 나뉘어 변화하면서 구동 온도에 따른 ICP 광원의 광학적 특성을 알아보았다. 휘도는 온도의 상승과 비례적으로 증가하였으나 $46.7[^{\circ}C]$ 이상에서는 오히려 감소하는 결과를 얻을 수 있었다. 파센법칙과 함께 보일-샤를의 법칙을 통해 0.02[Torr]의 압력이 변화함에 따라 더 높은 방전전압이 요구되지만 충분한 전압이 안정기에서 공급되지 못하기 때문이라 판단된다. 이와 더불어 방전관 길이에 따라 광원에 인가되는 전력과 전류을 측정하였다.