Illumination with solid state lighting technology

Steigerwald, D. A.; Bhat, J.; Collins, D. M.; Fletcher, R. M.; Holcomb, M.O.; Ludowise, M. J.; Martin, P.; Rudaz, Serge

doi:10.1109/2944.999186

Cited by 1,042 publications

(442 citation statements)

References 16 publications

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“…LEDs are direct band-gap semiconductor p-n junction diodes. The band-gap of the semiconductor, controlled by mixing different proportion of Ill-V elements from the periodic table, defines the light color frequency of the diode [5]. The band-gap of the LED may therefore change from time to time during operation where the junction temperature changes with power dissipation and the ambient temperature as well as device aging.…”

Section: Introductionmentioning

confidence: 99%

Color Control System for RGB LED Light Sources Using Junction Temperature Measurement

Wong

Tse

2007

IECON 2007 - 33rd Annual Conference of the IEEE Industrial Electronics Society

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Abstract-The efficiency of LED lights is approaching that of fluorescent lamps. LED light sources are finding more applications than conventional light bulbs due to their compactness, lower heat dissipation, and most importantly, real-time color changing capability. Accurate control of colors for RGB LED lights is a challenging task, which includes optical color mixing, color light intensity control and color point maintenance due to LED junction temperature change and device aging. In this paper , we present a LED junction temperature measurement technique for a pulse width modulation (PWM) diode forward current controlled RGB LED lighting system. The technique can control the color effectively without the need for using expensive feedback systems involving light sensors. Performance of chromaticity and luminance stability for a temperature compensated RGB LED system will be presented.

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Section: Introductionmentioning

confidence: 99%

Color Control System for RGB LED Light Sources Using Junction Temperature Measurement

Wong

Tse

2007

IECON 2007 - 33rd Annual Conference of the IEEE Industrial Electronics Society

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“…Solid-state lighting technology employs the principle of injection electroluminescence in semiconductor junctions used directly or in conjunction with either partial or complete conversion in phosphors [2,8,9]. Such an approach suggests high versatility in composing the spectral power distribution (SPD) of a light source and thus in controlling colour quality of illumination [10].…”

Section: Introductionmentioning

confidence: 99%

Colour-rendition properties of solid-state lamps

Žukauskas¹,

Vaicekauskas²,

Shur³

2010

J. Phys. D: Appl. Phys.

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The applicability of colour quality metrics to solid-state light sources is validated and the results of the assessment of colour rendition characteristics of various lamps are presented. The standard colour rendering index metric (CRI) or a refined colour quality scale metric (CQS) fail to distinguish between two principle colour rendition properties of illumination: the ability to render object colours with high fidelity and the ability to increase chromatic contrast, especially when the spectra of light sources contain a few narrow-band electroluminescence components.Supplementing these metrics by the known figures of merit that measure the gamut area of a small number of test colour samples does not completely resolve this issue. In contrast, the statistical approach, which is based on sorting a very large number of test colour samples with respect of just perceivable colour distortions of several kinds, offers a comprehensive assessment of colour rendition properties of solid-state light sources. In particular, two statistical indices, colour fidelity index (CFI) and colour saturation index (CSI), which are the relative numbers of object colours rendered with high fidelity and increased saturation, respectively, are sufficient to reveal and assess three distinct types of solid state light sources. These are (i) high-fidelity lamps, which cover the entire spectrum with the spectral components present in the wavelength ranges of both 530-610 nm and beyond 610 nm (e.g. trichromatic warm white phosphor converted LEDs, red-amber-green-blue LED clusters, complementary clusters of white and coloured LEDs); (ii) colour-saturating lamps, which lack power in the 530-610 nm wavelength range (e.g. red-green-blue or red-cyan-blue LED clusters); and (iii) colour dulling lamps, which lack power for wavelengths longer than 610 nm (dichromatic daylight phosphor converted LEDs and amber-green-blue LED clusters). Owing to a single statistical format, CSI and CFI can be used for design and optimization of multiwavelength LED clusters providing "smart" illumination with a trade-off between different colour rendition characteristics.

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“…Exhibiting the dual function of illumination and data transmission, the advantages of LEDs are multi-fold, such as low heat generation [23], low power consumption [24], high energy conversion efficiency/luminous efficacy [25] as well as a potentially high bandwidth [26], etc. Diverse types of LEDs have been developed, which are available in commercial markets, including phosphor converted LEDs (PC-LEDs) [27], multi-chip LEDs (MC-LEDs) [28], organic LEDs (OLEDs) [29] and micro-LEDs [30].…”

Section: Vlc Linksmentioning

confidence: 99%

Optimization of Visible-Light Optical Wireless Systems: Network-Centric Versus User-Centric Designs

Zhang

Hanzo

2018

IEEE Commun. Surv. Tutorials

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Abstract-In order to counteract the explosive escalation of wireless tele-traffic, the communication spectrum has been gradually expanded from the conventional radio frequency (RF) band to the optical wireless (OW) domain. By integrating the classic RF band relying on diverse radio techniques and optical bands, the next-generation heterogeneous networks (HetNets) are expected to offer a potential solution for supporting the ever-increasing wireless tele-traffic. Owing to its abundant unlicensed spectral resources, visible light communications (VLC) combined with advanced illumination constitute a competent candidate for complementing the existing RF networks. Although the advantages of VLC are multi-fold, some challenges arise when incorporating VLC into the classic RF HetNet environments, which may require new system architectures. The user-centric (UC) design principle for VLC environments constitutes a novel and competitive design paradigm for the super dense multi-tier cell combinations of HetNets. The UC concept may be expected to become one of the disruptive techniques to be used in the forthcoming fifthgeneration era. This paper provides a comprehensive survey of visible-light-aided OW systems with special emphasis on the design and optimization of VLC networks, where the radically new UC design philosophy is reviewed. Finally, design guidelines are provided for VLC systems.

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Illumination with solid state lighting technology

Cited by 1,042 publications

References 16 publications

Color Control System for RGB LED Light Sources Using Junction Temperature Measurement

Color Control System for RGB LED Light Sources Using Junction Temperature Measurement

Colour-rendition properties of solid-state lamps

Optimization of Visible-Light Optical Wireless Systems: Network-Centric Versus User-Centric Designs

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