Bichromatic to polychromatic photo-conversion LEDs

Abstract

Understanding of white light, the surrounding definitions that define it, and how these techniques are applied to traditional white light sources and solid-state light (SSL) sources, is challenging. As these definitions were developed for and are directly relational to the various forms of traditional incandescent and fluorescent lighting technologies, they can affect true understanding of newer SSL sources, such as LEDs. Additionally, this body of characterization techniques and their underlining calculus, that was defined and developed for traditional sources years ago, presents a challenging body of work to first understand and then be used to comprehend data obtained via these techniques from the testing of LEDs. As LEDs are used more and more in the replacement of traditional light sources, their definition from manufacturers, the very testing techniques used in their characterization, and the resulting data that is used to specify them, may be somewhat problematic in the accuracy and/or the understanding of the outcome. This paper looks at the underlining structure that currently defines lighting and then discusses and concludes that LEDs are a truly different kind of white light source that needs some differentiation in terms of the comprehension and standards used for their development, specification and use.