At the frontiers of LED technology
there’s a race being run between
the leading semiconductor makers.
A huge amount of research and development expenditure is dedicated to bringing about higher luminous efficacy in light emitters. That means increasing the ratio of light produced to the amount of power the LED uses, measured in lumens per Watt (lm/W). This is a founding principle of energy efficient lighting.
It’s an understatement to say that Cree, Inc. is quite good at being the forerunner in this race.
Towards the end of March this year the North Carolina LED chip manufacturer smashed its own previous record when they announced a new benchmark of 303lm/W.
From the Cree press release comes this praise by a genuine lighting boffin which sums up the achievement nicely:
“This is truly an impressive accomplishment. Achieving this level of LED efficacy amplifies the potential for the solid-state-lighting industry to deliver smaller, lower-cost lighting solutions, and even larger-than-expected energy savings.”
- Steven DenBaars, Professor and Co-Director, Solid State Lighting and Energy Center, University of California, Santa Barbara.
So, what’s next?
"Well, there’s a theoretical limit 683lm/W for white light produced from solid state emitters. However, a lot of that light is occurring in the UV and infrared parts of the spectrum, leaving a supposed visible limit of somewhere between 250-370lm/W."
- Murphy, T W, “Spectral Luminous Efficacy of White Light”, Applied Physics, 111, 104909, (2013)
If we knew the ratio of invisible-to-visible light in this Cree laboratory wonder-chip, we’d better understand just how close they are to the limit. Alas.
To give an idea of where the commercial market is at the moment, here at Lighting Matters the most efficient residential fitting we stock is putting out 70-80lm/W.
So it seems it’s a long road that leads from the RnD laboratory to your ceiling.