scholarly journals Development of low power consumption LED light source for visible light spectrophotometry

2011 ◽  
Vol 12 ◽  
pp. 53-60
Author(s):  
Yoshiyuki Nakano ◽  
Yuzo Hosoe ◽  
Tetsuichi Fujiki ◽  
Yasushi Yoshikawa ◽  
Shuichi Watanabe
2021 ◽  
Vol 338 ◽  
pp. 01015
Author(s):  
Marek Markowicz ◽  
Emil Smyk ◽  
Robert Smusz

LEDs are widely used light sources. Their main advantages are low power consumption, mechanical strength, high luminous efficacy, and a lifetime exceeding 50 000 hours. However, compared to other light sources, they are more sensitive to high temperatures. Heat is generated by converting electrical energy into radiant energy. The share of heat in this transformation describes the efficiency, but in the case of light sources, efficiency is not one of the basic parameters because only a part of the radiation produced is visible light, which interests the recipients. However, the temperature has a big influence on the properties and lifetime of LEDs. This article presents the results of temperature measurements of the LED lamp.


2020 ◽  
Vol 10 (20) ◽  
pp. 7384
Author(s):  
Konthoujam James Singh ◽  
Yu-Ming Huang ◽  
Tanveer Ahmed ◽  
An-Chen Liu ◽  
Sung-Wen Huang Chen ◽  
...  

Visible Light Communication (VLC) technology is an emerging technology using visible light modulation that, in the modern world, will mainly facilitate high-speed internet connectivity. VLC provides tremendous advantages compared to conventional radio frequency, such as a higher transmission rate, high bandwidth, low-power consumption, no health hazards, less interference, etc., which make it more prominent in recent days. Due to their outstanding features, including low cost, low power consumption, etc., µ-light-emitting diodes (LEDs) have gained considerable attention for VLC implementation, but mostly for the ability to be used for lighting as well as communications. In this review paper, we will focus mainly on recent developments in VLC applications and various factors affecting the modulation bandwidth of VLC devices. Numerous factors, such as quantum confined stark effect (QCSE), carrier lifetime, carrier recombination time, crystal orientation, etc. affect the modulation bandwidth of LEDs, and more information will be discussed in the following sections. This paper will focus on VLC applications based on LEDs but mainly on semipolar μ-LEDs and μ-LED-based arrays with high bandwidths. Another important application of VLC is underwater optical wireless communication (UOWC), which has drawn a huge interest in marine exploration and underwater connectivity, but still faces some challenges because visible light is being used. In addition, this paper will focus on how the current VLC system modulation bandwidth can be enhanced. Many methods have been introduced, such as decreasing the active layer thickness or effective active area or using doping, but the bandwidth is restricted by the recombination time when the system configuration reaches its limit. Therefore, it is important to find alternative ways such as optimizing the system, using the blue filter or using the equalization technology, which will be addressed later. Overall, this review paper provides a brief overview of the VLC-based system performance and some of its potential prospects.


2020 ◽  
Vol 64 (1-4) ◽  
pp. 165-172
Author(s):  
Dongge Deng ◽  
Mingzhi Zhu ◽  
Qiang Shu ◽  
Baoxu Wang ◽  
Fei Yang

It is necessary to develop a high homogeneous, low power consumption, high frequency and small-size shim coil for high precision and low-cost atomic spin gyroscope (ASG). To provide the shim coil, a multi-objective optimization design method is proposed. All structural parameters including the wire diameter are optimized. In addition to the homogeneity, the size of optimized coil, especially the axial position and winding number, is restricted to develop the small-size shim coil with low power consumption. The 0-1 linear programming is adopted in the optimal model to conveniently describe winding distributions. The branch and bound algorithm is used to solve this model. Theoretical optimization results show that the homogeneity of the optimized shim coil is several orders of magnitudes better than the same-size solenoid. A simulation experiment is also conducted. Experimental results show that optimization results are verified, and power consumption of the optimized coil is about half of the solenoid when providing the same uniform magnetic field. This indicates that the proposed optimal method is feasible to develop shim coil for ASG.


2016 ◽  
Vol 136 (11) ◽  
pp. 1555-1566 ◽  
Author(s):  
Jun Fujiwara ◽  
Hiroshi Harada ◽  
Takuya Kawata ◽  
Kentaro Sakamoto ◽  
Sota Tsuchiya ◽  
...  

Nano Letters ◽  
2013 ◽  
Vol 13 (4) ◽  
pp. 1451-1456 ◽  
Author(s):  
T. Barois ◽  
A. Ayari ◽  
P. Vincent ◽  
S. Perisanu ◽  
P. Poncharal ◽  
...  

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