Electronic illumination systems are now available with multiple independently controllable LEDs of different spectral power distribution (SPD). These independent SPD can be combined in the proper proportions to replicate a target SPD. Generally at least four channels and sometimes eight or more channels are needed for a sufficiently broad tuning range with sufficiently high quality replication. As the number of independent channels rises above three, there are an infinite number of SPD that can achieve the same chromaticity. Algorithms employing a merit function are used to quickly sort to a good solution. In addition to spectrum, time is often an important quality of illumination such as with daylight and fire. A system that combines spectral tuning and time synchronization is referred to here as a light player. There are multiple optimization goals that may be of interest in determining the synthesized SPD. Examples include efficacy, color rendering, color saturation, high/low melanopic suppression, and smallest SPD error. One application of a light player is to replicate the time-varying SPD of daylight towards a healthier and more enjoyable indoor illuminated environment. Other applications include, retail appearance enhancement, medical diagnosis, horticulture, and standard illuminant synthesis such as D65. This talk will explore the general architecture of light players, the algorithms for synthesizing an SPD, summary information of daylight recordings, and a brief demonstration of a light player.
In recent years, there has been considerable press coverage about the promise of Solid State Lighting (SSL). Despite this
or perhaps because of the coverage, it can be difficult to separate hype from reality and set expectations for the near to
medium term. The short answer is there are good SSL products on the market now and some poor ones. The good ones
are getting better, more common, and more affordable. This paper will cover the basics of the key components that make
up a luminaire which are LEDs (light emitting diode), power supply, optics, and thermo/mechanical subsystems. Each
component will be reviewed with highlights as to what is important. These subsystems will then be considered as a
system. Several methodologies for designing both spot and area luminaires will be discussed focusing on non-residential
buildings. The topic of SSL lifetime will be discussed. Finally, trends will be explored to provide an understanding of the
kinds of improvements one can expect and the timeframe over which they may occur.
High-power Light Emitting Diodes (LEDs) were introduced in the market in 1998 by Lumileds. High-power LEDs have unique properties, very different from conventional light sources, creating never before possible solutions available to lighting designers. In this paper we will give an update on these devices and discuss the main benefits of LEDs compared to more traditional light sources. We will show that the benefits of high-power LEDs also relate to the organization of light they emit. Comparisons of more and less organized light sources as well as applications for highpower LEDs will be discussed.
KEYWORDS: Light emitting diodes, Visible radiation, Sun, Solid state lighting, Black bodies, Control systems, Light sources and illumination, Telecommunications, Blue light emitting diodes, LED lighting
The common approaches to solid state white lighting include phosphor conversion of blue or UV sources and combining red, green, and blue LEDs. However these methods only begin to address the reproduction of the complex, time-varying spectra humans call light. This paper will suggest a massive primary approach to solid state lighting and communication. LEDs allow an economic means to divide up the visible spectrum into many individually controllable slices, which can then be used in harmony to reproduce the desired illumination. It will also be suggested that the evolution and development of the radio frequency spectrum and high fidelity audio can provide guidance to exploiting the visible spectrum.
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