Searched for: subject%3A%22light%255C-emitting%255C+diodes%255C+%255C%2528LEDs%255C%2529%22
(1 - 14 of 14)
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Wen, Minzhen (author), Ibrahim, Mesfin Seid (author), Meda, Abdulmelik Husen (author), Zhang, Kouchi (author), Fan, J. (author)
High-power white light-emitting diodes (LEDs) have demonstrated superior efficiency and reliability compared to traditional white light sources. However, ensuring maximum performance for a prolonged lifetime use presents a significant challenge for manufacturers and end users, especially in safety–critical applications. Thus, identifying...
journal article 2024
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Herzog, Alexander (author), Benkner, Simon (author), Zandi, Babak (author), Buffolo, Matteo (author), van Driel, W.D. (author), Meneghini, Matteo (author), Khanh, Tran Quoc (author)
We report on the degradation mechanisms and dynamics of silicone encapsulated ultraviolet A (UV-A) high-power light-emitting diodes (LEDs), with a peak wavelength of 365nm. The stress tests were carried out for a period of 8665 hours with forward currents between 350mA and 700mA and junction temperatures up to 132°C. Depending on stress...
journal article 2023
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Herzog, Alexander (author), Wagner, Max (author), Benkner, Simon (author), Zandi, Babak (author), van Driel, W.D. (author), Khanh, Tran Quoc (author)
We report on the degradation dynamics and mechanisms of the commercially available chip-on-board (COB) high-power light-emitting diode (LED) modules with an electrical power of 175 W. Due to the associated thermal load, the temperature dependence of the aging processes is additionally analyzed within the scope of this work. The aging tests...
journal article 2022
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Hueting, R. J.E. (author), De Vries, H. (author), Dutta, S. (author), Annema, A. J. (author)
The CMOS silicon avalanche-mode light-emitting diode (AMLED) has emerged as a potential light source for monolithic optical interconnects. Earlier we presented a superjunction light-emitting diode (SJLED) that offers a higher electroluminescent intensity compared to a conventional AMLED because of its more uniform field distribution. However,...
journal article 2021
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Ibrahim, Mesfin Seid (author), Fan, J. (author), Yung, Winco K.C. (author), Jing, Zhou (author), Fan, Xuejun (author), van Driel, W.D. (author), Zhang, Kouchi (author)
The increased system complexity in electronic products brings challenges in a system level reliability assessment and lifetime estimation. Traditionally, the graph model-based reliability block diagrams (RBD) and fault tree analysis (FTA) have been used to assess the reliability of products and systems. However, these methods are based on...
journal article 2021
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Yazdan Mehr, M. (author), Bahrami, A. (author), van Driel, W.D. (author), Fan, X.J. (author), Davis, J.L. (author), Zhang, Kouchi (author)
In this paper, degradation mechanisms of optical materials, used in the light emitting diode (LED)-based products, are reviewed. The LED lighting is one of the fastest technology shifts in human history. Lighting accounts for almost 20% of the global electrical energy use, inferring that replacement of traditional lighting sources with LEDs...
journal article 2020
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Ibrahim, Mesfin Seid (author), Fan, Jiajie (author), Yung, Winco K.C. (author), Prisacaru, Alexandru (author), van Driel, W.D. (author), Fan, X. (author), Zhang, Kouchi (author)
Light-emitting diodes (LEDs) are among the key innovations that have revolutionized the lighting industry, due to their versatility in applications, higher reliability, longer lifetime, and higher efficiency compared with other light sources. The demand for increased lifetime and higher reliability has attracted a significant number of...
review 2020
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Ibrahim, M.S. (author), Fan, J. (author), Yung, Winco K.C. (author), Wu, Zeyu (author), Sun, B. (author)
Nowadays, due to the advancement of design and manufacturing technology, there are many consumer products with high reliability. Similarly, the competition in the business sector influences the product development time to become shorter and that makes it difficult for manufacturers to evaluate the reliability of current products before new...
journal article 2019
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Cai, Miao (author), Yang, Daoguo (author), Huang, J. (author), Zhang, Maofen (author), Chen, Xianping (author), Liang, Caihang (author), Koh, S.W. (author), Zhang, Kouchi (author)
The color coordinate shift of light-emitting diode (LED) lamps is investigated by running three stress-loaded testing methods, namely step-up stress accelerated degradation testing, step-down stress accelerated degradation testing, and constant stress accelerated degradation testing. A power model is proposed as the statistical model of the...
journal article 2017
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Koladouz Esfahani, Z. (author), Tohidian, M. (author), van Zeijl, H.W. (author), Kolahdouz, Mohammadreza (author), Zhang, Kouchi (author)
Given the performance decay of high-power light-emitting diode (LED) chips over time and package condition changes, having a reliable output light for sensitive applications is a point of concern. In this study, a light feedback control circuit, including blue-selective photodiodes, for blue/ultraviolet (UV) LED, has been designed and...
journal article 2017
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Dong, J. (author), Zhang, Kouchi (author)
In lighting systems consisting light-emitting diodes (LEDs), excessive temperature is a main cause of degraded luminous efficacy, which leads to reduced average illuminance and distorted illumination rendering. Modeling the thermal dynamics of LEDs is hence essential in designing thermal dissipators and controllers for maintaining constant...
journal article 2017
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Li, Z. (author)
As a promising technology, photocatalysis shows its unique advantages and potential in many disciplines, from hydrogen production, indoor and outdoor air purification, remediation of non-biodegradable molecular in the factory, to the organic synthesis with high selectivity. In recent years, photocatalytic semiconductor process has shown a high...
master thesis 2016
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Yazdan Mehr, M. (author), van Driel, W.D. (author), Zhang, Kouchi (author)
In this paper, progresses of color maintenance, also known as color shift, in solid-state lighting (SSL) systems are thoroughly reviewed. First, color shift is introduced and a few examples are given from different real-life industrial conditions. Different degradation mechanisms in different parts of the system are also explained. Different...
review 2015
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Liu, S. (author)
The United Kingdom (UK) government policy is increasingly directed at transforming the built environment to an environmentally sustainable one. The government, for example, has set a target for a reduction in carbon emissions by 80% by 2050 compared to 1990 levels. A large number of new policies and regulations are being introduced to minimise...
conference paper 2011
Searched for: subject%3A%22light%255C-emitting%255C+diodes%255C+%255C%2528LEDs%255C%2529%22
(1 - 14 of 14)