LEDs become a brighter prospect but will more consumers see the light?

Too expensive, cold looking and not as durable as some of the sales hype would have you believe. These are still doubts that keep consumers dithering over whether to invest in LED lighting systems. But are they right to be cautious? Not anymore. Recent advances in LED technology now mean there are no excuses left for consumers reticence, except maybe some environmental doubts. But as recycling strategies improve even these are dwindling.

Before looking at a recent technological breakthrough in LEDs that will boost consumer confidence lets do the maths.

LEDs last between 40,000 and 95,000 hours, and if an LED operates for 12 hours daily this would potentially give a life span of approx 20 years.

An LEDs longevity all comes down to the question of lumen depreciation. Some experts reckon that once an LED reaches 30% depreciation its lifespan is pretty much over, although in fairness it will continue to work but with reduced light output.

Not surprisingly one of the key operating factors impacting LED lifetime performance relates to the temperature at the junction where the diode connects to its base. The theory is simple enough. Keep junction temperatures low and the rate of lumen depreciation decreases. What's needed here is effective heat dissipation designs and there are plenty of those around. The real design challenge is that most LEDs are contained within a resin that is just not that good at letting heat go.

The heat that LEDs generate stems from the P-N junction that is created in semiconductor–based devices.

As electrons travel in the structure of the semiconductor they fill electron holes and emit photons, a form of light. The heat developed at the P-N junction is actually electrical energy that has not been converted into light. It is imperative that this heat be conducted away via conduction, convection or radiation methods.

So LEDs must efficiently transfer as much heat as possible away from the P-N junction because a heat-stressed LED will lose efficiency and light output will diminish and could possible fail altogether. So what is the recent breakthrough that will add to consumer confidence? Well, it involves a claim that LED system costs can be cut by 40% which is no mean feat.

American technology company Cree has developed XLamp Extreme High Power (XHP) LEDs, which it proudly proclaims is a new class of LEDs that enable a system cost reduction of up to 40%. These LEDs are powered by Cree’s SC5 technology platform called XLamp XHP50. This, claims the company, means XHP LEDs provide twice the lumen output and improved reliability compared to previous LEDs of the same size.

So just how are these big cost savings achieved? Apparently, XHP LEDs will allow lighting manufacturers to reduce the size and cost of their lighting system design by using fewer, more reliable LEDs to achieve the same brightness. XHP LEDs enable new lighting designs that require fewer optics, smaller PCBs and a smaller housing. The designers of XHP LEDs also believe the technology will achieve longer lifetimes even at higher operating temperatures and currents than previous LED technology, Technically this will allow lighting manufacturers to reduce heat sink size and cost without jeopardising lifetime rates.

These LEDs also go beyond the previously perceived operational limit of lumen density by delivering up to 2546 lumens at 19 watts from a 5.0 x 5.0 mm package and up to 4022 lumens at 32 watts from a 7.0 x 7.0 mm package, respectively.

So increased performance while cutting costs adds more grist to the LED mill. And don't forget some of the other operational advantages LEDs have. They don’t emit ultraviolet (UV) radiation, they don’t attract insects and migraine sufferers like the fact they don't flicker.

So I believe that consumer attitudes to LED lighting will change and recent figures from analysts Lux Research agree with that. It reckons that in eight years time the global market for that technology will be worth a radiant €28 billion.