Wednesday July 13, 2016
Thanks to their various benefits, LEDs have become an integral part of general lighting applications as semiconductor light sources. For some time, LED efficiency has been significantly higher than that of conventional lighting technologies. But how do we define efficiency in a solid-state lighting (SSL) system? In ordinary everyday language, when we talk about the efficiency of light sources, we generally mean their luminous efficacy, which is measured in lumens per watt (lm/W), a metric that takes into account the sensitivity of the human eye. Another measure is efficiency characterized by radiometric power. Let's consider the impacts of efficacy and efficiency, and discuss the decision-making process product developers must follow, which impacts overall system efficiency.
Establishing an efficacy metric involves determining the photometric luminous flux of the light source (lm) in relation to the electrical input power (W). The alternative photometric radiation equivalent, conversely, does not consider the sensitivity of the human eye but is a pure efficiency measure. The optical radiometric output power (W) is divided by the electrical input power (W) to yield a percent efficiency. The efficiency of LEDs depends on many different factors. We will look at some of these in detail in this article.
Read the entire article here: http://www.ledsmagazine.com/articles/print/volume-13/issue-5/features/developer-forum/understand-the-factors-and-adaptations-that-impact-led-efficiency.html