Searched for: subject:"Light%5C+emitting%5C+diodes"
(1 - 18 of 18)
document
Lu, G. (author)
Luminous flux maintenance and color stability are two important factors to evaluate the lighting quality. Where a significant amount of research efforts are performed on the former and even some standards have been generated for lumen decay acceleration, research activities and achievements on the latter are lagging behind. DOE Energy Star...
doctoral thesis 2017
document
Kolahdouz Esfahani, Zahra (author), Tohidian, M. (author), van Zeijl, H.W. (author), Kolahdouz, Mohammadreza (author), Zhang, G.Q. (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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Cai, Miao (author), Yang, Daoguo (author), Huang, J. (author), Zhang, Maofen (author), Chen, Xianping (author), Liang, Caihang (author), Koh, S.W. (author), Zhang, G.Q. (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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Yazdan Mehr, M. (author), Volgbert, S. (author), van Driel, W.D. (author), Zhang, G.Q. (author)

A graphene monolayer has been successfully coated on one side of a bisphenol-A-polycarbonate (BPA-PC) plate, used as a substrate for remote phosphor applications in light-emitting diode (LED)-based products. Using a photoresist transferring method, graphene sheet has been coated on BPA-PC plates. The results show that this graphene monolayer...

journal article 2017
document
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
document
Yazdan Mehr, M. (author), van Driel, W.D. (author), Zhang, G.Q. (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
document
Ye, H. (author)
Solid-State Lighting (SSL), powered by Light-Emitting Diodes (LEDs), is an energy-efficient technology for lighting systems. In contrast to incandescent lights which obtain high efficiency at high temperatures, the highest efficiency of LEDs is reached at low temperatures. The thermal management in LED product is then a key design parameter as...
doctoral thesis 2014
document
Thomas, W. (author)
The growing energy consumption of lighting as well as rising luminous efficacies and -fluxes of high-power Light Emitting Diodes (LEDs) have contributed to the widespread use of LEDs in modern lighting systems. One of the most prominent users of the LED-technology is automotive (exterior) lighting. It benefits from LEDs’ high efficiencies and...
doctoral thesis 2014
document
Ten Kate, O.M. (author), De Jong, M. (author), Hintzen, H.T. (author), Van der Kolk, E. (author)
Solar cells of which the efficiency is not limited by the Shockley-Queisser limit can be obtained by integrating a luminescent spectral conversion layer into the cell structure. We have calculated the maximum efficiency of state-of-the-art c-Si, pc-Si, a-Si, CdTe, GaAs, CIS, CIGS, CGS, GaSb, and Ge solar cells with and without an integrated...
journal article 2013
document
Oostra, A.J. (author), Van den Bos, K.H.W. (author), Michels, J.J. (author), Blom, P.W.M. (author)
Organic materials open the way for large-scale applications of Organic Light-Emitting Diodes (OLED) and solar cells (OPV). These materials can be large-scale processed using printing and coating on rigid and flexible substrates. The resulting devices can therefore be fabricated at low cost for various applications. Production yields suffer,...
conference paper 2013
document
Rooijakkers, M.S. (author)
This graduation project has been executed in cooperation with Philips Research and Holst Centre, within the Platform for Large Area Conformable Electronics by InTegration (PLACE-it) project. The scope of the project is to identify required developments for OLED textile, to fulfill the needs of future users and minimise the environmental impact....
master thesis 2011
document
Roscam Abbing, F.D. (author)
Given the temperature dependence of various aspects of light-emitting diode (LED) performance, LED temperature sensing is becoming increasingly important in solid-state lighting applications. This thesis presents an electrical technique for junction-temperature sensing based on the measurement of the forward voltage and current of an LED at two...
master thesis 2011
document
Lafont, U. (author), Van Zeijl, H.W. (author), Van der Zwaag, S. (author)
conference paper 2011
document
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
document
Dong, J. (author), Van Driel, W. (author), Zhnag, G. (author)
This paper describes a new design concept of automatically diagnosing and compensating LED degradations in distributed solid state lighting (SSL) systems. A failed LED may significantly reduce the overall illumination level, and destroy the uniform illumination distribution achieved by a nominal system. To our knowledge, an automatic scheme to...
journal article 2011
document
Naeimi, A. (author)
OLED is a current based device, which emitted amount of light depends on the current supplied to the device so steady current flow is needed. In Active Matrix Organic Light Emitting Diode (AMOLED) Display. TFTs are used as driving transistors for OLED. Because of the non uniformity of the TFTs, variation in threshold voltage and mobility has a...
master thesis 2011
document
Janssen, O.T.A. (author), Wachters, A.J.H. (author), Urbach, H.P. (author)
The incoherent emission of periodically structured Light Emitting Diodes (LEDs) can be computed at relatively low computational cost by applying the reciprocity method. We show that by another application of the reciprocity principle, the structure of the LED can be optimized to obtain a high emission. We demonstrate the method by optimizing one...
journal article 2010
document
Young, I.T. (author), Garini, Y. (author), Dietrich, H.R.C. (author), Van Oel, W. (author), Liqui Lung, G. (author)
Traditional light sources for fluorescence microscopy have been mercury lamps, xenon lamps, and lasers. These sources have been essential in the development of fluorescence microscopy but each can have serious disadvantages: lack of near monochromaticity, heat generation, cost, lifetime of the light source, and possible distortions due to...
conference paper 2004
Searched for: subject:"Light%5C+emitting%5C+diodes"
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