scholarly journals Photobiocatalytic alcohol oxidation using LED light sources

2017 ◽  
Vol 19 (2) ◽  
pp. 376-379 ◽  
Author(s):  
M. Rauch ◽  
S. Schmidt ◽  
I. W. C. E. Arends ◽  
K. Oppelt ◽  
S. Kara ◽  
...  
Keyword(s):  
Light Source ◽  
Photocatalytic Oxidation ◽  
Alcohol Oxidation ◽  
Light Sources ◽  
Blue Led ◽  
Led Light

The photocatalytic oxidation of NADH using a flavin photocatalyst and a simple blue LED light source is reported.

scholarly journals Analysis on High-Power Seaport LED Luminaire with Uniform Light Distribution Based on Optimized Lens and Heatsink

2021 ◽  
Vol 11 (9) ◽  
pp. 4035
Author(s):  
Jinsheon Kim ◽  
Jeungmo Kang ◽  
Woojin Jang
Keyword(s):  
Light Source ◽  
High Power ◽  
Heat Dissipation ◽  
Light Emitting Diode ◽  
Light Distribution ◽  
Light Sources ◽  
Led Light ◽  
High Power Led ◽  
Distribution Requirement ◽  
Lighting Application

In the case of light-emitting diode (LED) seaport luminaires, they should be designed in consideration of glare, average illuminance, and overall uniformity. Although it is possible to implement light distribution through auxiliary devices such as reflectors, it means increasing the weight and size of the luminaire, which reduces the feasibility. Considering the special environment of seaport luminaires, which are installed at a height of 30 m or more, it is necessary to reduce the weight of the device, facilitate replacement, and secure a light source with a long life. In this paper, an optimized lens design was investigated to provide uniform light distribution to meet the requirement in the seaport lighting application. Four types of lens were designed and fabricated to verify the uniform light distribution requirement for the seaport lighting application. Using numerical analysis, we optimized the lens that provides the required minimum overall uniformity for the seaport lighting application. A theoretical analysis for the heatsink structure and shape were conducted to reduce the heat from the high-power LED light sources up to 250 W. As a result of these analyses on the heat dissipation characteristics of the high-power LED light source used in the LED seaport luminaire, the heatsink with hexagonal-shape fins shows the best heat dissipation effect. Finally, a prototype LED seaport luminaire with an optimized lens and heat sink was fabricated and tested in a real seaport environment. The light distribution characteristics of this prototype LED seaport luminaire were compared with a commercial high-pressure sodium luminaire and metal halide luminaire.

scholarly journals Investigation on optical integration between LED Mid-IR light sources and Si-based waveguides for sensing applications

2021 ◽  
Vol 2145 (1) ◽  
pp. 012056
Author(s):  
Pawaphat Jaturaphagorn ◽  
Papichaya Chaisakul ◽  
Nattaporn Chattham ◽  
Pichet Limsuwan
Keyword(s):  
Integrated Circuits ◽  
Light Source ◽  
Light Emitting Diode ◽  
Coupling Scheme ◽  
Light Sources ◽  
Optical Coupling ◽  
Led Light ◽  
Carbon Dioxide Gas ◽  
Sensing Applications ◽  
Ir Light

Abstract Research on mid-IR silicon-based waveguides has recently received strong interest. Particularly, this paper focuses on one of the critical issues in micron-scale photonic integrated circuits, which is to efficiently couple a mid-IR LED (light emitting diode) light source to an external micron-scale waveguide. The optical coupling scheme is crucial for the exploitation of LED light sources in waveguide-based spectroscopic sensing applications. This paper reports optical coupling scheme between an LED mid-IR light source and a silicon rich silicon nitride (SiN) waveguide that could enable the use of LED-based light sources. Finally, the detection limit of the investigated device for carbon dioxide gas detection is calculated.

scholarly journals Light Emitted Diode on Detecting Thin-Film Transistor through Line-Scan Photosensor

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 434
Author(s):  
Fu-Ming Tzu ◽  
Jung-Shun Chen ◽  
Shih-Hsien Hsu
Keyword(s):  
Thin Film ◽  
Light Source ◽  
High Spatial Resolution ◽  
Thin Film Transistor ◽  
Light Sources ◽  
Charge Coupled Device ◽  
Blue Led ◽  
The Third ◽  
Optical Inspection ◽  
Via Hole

This paper explores the effectiveness of the white, red, green, and blue light emitted diodes (LEDs) light sources to detect the third layer of the electrode pixel and the fourth layer of the via-hole passivation on thin-film transistors. The time-delay-integration charge-coupled device and a reflective spectrometer were implemented in this experiment. The optical conditions are the same, as each light source and the digital image’s binary method also recognize the sharpness and contrast in the task. Consequently, the white and the blue LED light sources can be candidates for the light source for the optical inspection, especially for monochromic blue LED’s outperformance among the light sources. The blue LED demonstrates the high spatial resolution and short wavelength’s greater energy to trigger the photosensor. Additionally, the metal material has shown a tremendous responsibility in the photosensor with 150 Dn/nj/cm2 over the sensibility. The mercury 198Hg-pencil discharge lamp emits the stable spectral wavelength to significantly calibrate the spectrometer’s measurement.

scholarly journals New LED lamp design with heat pipes

2019 ◽  
pp. 34-42 ◽  
Author(s):  
D. V. Pekur ◽  
Yu. E. Nikolaenko ◽  
V. M. Sorokin
Keyword(s):  
Heat Exchanger ◽  
Thermal Resistance ◽  
Light Source ◽  
Cooling System ◽  
Heat Pipes ◽  
Ambient Air ◽  
Light Sources ◽  
Heat Conducting ◽  
Led Light ◽  
Semiconductor Crystals

The problem of climate change poses a challenge for humanity: it is necessary to reduce harmful emissions into the atmosphere, caused mainly by the burning of coal in thermal power plants. Partially, this problem can be solved by the use of energy-saving devices and equipment, including the replacement of traditional light sources with more efficient LEDs. This, however, causes the problem of ensuring normal thermal modes of the LEDs, since the more powerfull the LED is, the more heat is released in their semiconductor crystals, which leads to an increase in the temperature of the crystals and a decrease in the reliability of the device. This problem becomes especially urgent when using powerful multi-chip LED light sources, the so-called SOB matrices, whose power even now exceeds 500 W. This article presents a new design of a powerful LED lamp for indoor illumination of rooms with low ceilings. The heat from the LED is transferred via heat pipes to the heat exchanger rings looped around the light source. The heat exchanger rings are cooled by the natural convection of the surrounding air (at an ambient air temperature of 20°C). Computer simulation allowed evaluating the ability of the proposed cooling system to provide a normal thermal mode of the LED light source. The results on the computer simulations of the temperature field of light source`s cooling system showed that when the LED power is 300 W, the temperature of the light source`s base at the point where it is connected to the light source does not exceed 67.6°C. When the contact zone is covered with a 0.1 mm layer of heat-conducting paste (Arctiс Silver 5 type) with a thermal conductivity coefficient of 8.7 W/(m•°C), the temperature of the LED case reaches 70°C. If the thermal resistance of the LED light source is 0.1°C/W, then the temperature of its semiconductor crystals will be 100°C, well below the allowable temperature value of 150°C. The total thermal resistance of the cooling system is 0.159°C/W.

scholarly journals Lifetime Prediction method of LED Light-emitting Device Based on Approximate Analysis

2021 ◽  
Vol 271 ◽  
pp. 01031
Author(s):  
Cai Wenting ◽  
Li Sheng ◽  
Meng Qinghui ◽  
Huang Haisong
Keyword(s):  
Approximate Method ◽  
Light Source ◽  
High Efficiency ◽  
Light Flux ◽  
Prediction Method ◽  
Light Sources ◽  
Light Emitting ◽  
Led Light ◽  
Long Life ◽  
Application Requirements

Compared with other light sources, LED light source has a longer service life and will not suddenly fail. Due to its high efficiency, energy saving and long life, LED has become the most popular light source at present. However, it is no longer considered to meet the application requirements, and the time that the light flux decays to this level is considered to be the life of the LED. This paper introduces the approximate method used to predict the lumen maintenance life of LED lamps. The experimental results obtained by the approximate method are compared with the TM-21 standard. Eventually, it is concluded that the approximate method provides more reliability information than the original TM-21 standard, and the obtained results are more reference, more accurate and more reliable.

scholarly journals Discomfort Glare Caused by White LED Light Sources-Effect of Light Source Position-

2006 ◽  
Vol 90 (11) ◽  
pp. 822-827 ◽  
Author(s):  
Hiroshi Takahashi ◽  
Takashi Irikura ◽  
Masahiro Toda ◽  
Takayoshi Moriyama
Keyword(s):  
Light Source ◽  
Light Sources ◽  
White Led ◽  
Source Position ◽  
Led Light ◽  
Discomfort Glare ◽  
Effect Of Light

scholarly journals Lifespan Characteristics of SMD-Type LED Exit Lights

2021 ◽  
Vol 21 (2) ◽  
pp. 59-64
Author(s):  
Jongjin Jung
Keyword(s):  
Light Source ◽  
Heat Dissipation ◽  
Light Sources ◽  
Improve Product Quality ◽  
Electrical Characteristics ◽  
Led Light ◽  
Source Current ◽  
The Relationship ◽  
Top View ◽  
Future Management

In this study, the electrical characteristics of SMD-type LED light sources, which have been used for most exit lights since 2007, were analyzed. The relationship between the electrical characteristics of the LED light source and the life of the light source was analyzed. An LED exit light that used a top-view LED and a power LED was used for this experiment. The sizes of the exit lights were medium and small. In addition, the electrical characteristics of the LED light source were analyzed by measuring the input current, light source current, and power values related to the life of the LED. As a result, when the exit lights were of the same size, the top-view LED exit light required less power and lower current than the power LED exit light, and the current and power waveforms were also good. It was also confirmed that the power LED exit light was out of the range of rated power for some samples. Therefore, when developing an LED exit light, checking the voltage, current, power, and heat dissipation of the light source together will improve product quality and future management.

scholarly journals Effectiveness of Light Source on Detecting Thin Film Transistor

Crystals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 394 ◽  
Author(s):  
Fu-Ming Tzu ◽  
Jung-Hua Chou
Keyword(s):  
Thin Film ◽  
Light Source ◽  
Thin Film Transistor ◽  
Metal Halide ◽  
Light Sources ◽  
Blue Led ◽  
Optical Inspection ◽  
Metal Halide Lamps ◽  
Better Than ◽  
Halogen Lamps

Light sources tend to affect images captured in any automatic optical inspection (AOI) system. In this study, the effectiveness of metal-halide lamps, quartz-halogen lamps, and LEDs as the light sources in AOI systems for the detection of the third and fourth layers electrodes of thin-film-transistor liquid crystal displays (TFT-LCDs) is examined experimentally. The results show that the performance of LEDs is generally comparable or better than that of metal-halide and quartz-halogen lamps. The best optical performance is by the blue LED due to its spectrum compatibility with the time-delay-integration charged-coupled device (TDI CCD) sensor and its better spatial resolution. The images revealed by the blue LED are sharper and more distinctive. Since current LEDs are more energy efficient and environmentally friendly, using LEDs as the light source for AOI is very beneficial. As the blue LED performs the best, it should be adopted for AOI using TDI CCD sensors.

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