Tag Archives: LED

Firefly belly inspires way to enhance LED brightness by 55 per cent

firefly_LED-1024x671A fond memory of my family’s annual camping weekend at Sandbanks Provincial Park is the late-night walk to the comfort station just before hitting the tents.

With the sound of crickets haunting the evening and smell of campfire smoke on their hoodies, my daughters carefully scan the darkness in search of fireflies, or in their world fairies with magic dust.

We never grow bored of these amazing little creatures, which through an oxygen-induced chemical reaction that takes place in their lower abdomen can cause their bellies to light up. The process is called bioluminescence, and it has earned these small flying beetles the nickname “lightning bugs.”

Human observation of fireflies throughout history has led to some useful products, such as emergency glow sticks, which offer the benefit of not needing batteries. But researchers have struggled to achieve the kind of efficiencies studied in fireflies.

One answer to the puzzle, it seems, has nothing to do with chemical reactions. Earlier this month, in two research papers published in the journal Optics Express, scientists from Belgium, Canada and France revealed that the design of a firefly’s abdomen plays an important role in enhancing the bug’s trademark glow.

In fact, they were able to replicate the outside structure of the firefly’s “lanterns” — the organs within the insect’s abdomen — to create a coating that, when applied to the surface of a light-emitting diode (LED), boosted light efficiency by roughly 55 per cent.

It’s a classic example of biomimicry in action. “There are many things in nature that can be adapted for many fields,” said nanotechnology specialist Ali Belarouci, a senior research scientist at the University of Sherbrooke in Quebec. “With the equipment we have today we’re able to see phenomena (in nature) we couldn’t see before.”

Belarouci said Belgian researchers were studying firefly lanterns with an electron microscope when they noticed a pattern of irregular scales with sharp edges and protruding tips. Using computer simulations, they looked at how these scales might affect the transmission of light out of the abdomen.

What was interesting is that the scales, which they described as having the shape of a factory roof, could be viewed at the micrometer level — that is, each scale tip was positioned about 10 micrometres apart, or about one-tenth the width of a human hair.

Small to us, a micrometre is massive in the world that defines nanotechnology, and this is where previous research on fireflies and other insects had largely focused. But at that level, the structures were observed to have a small impact on efficiency — a few per cent increase at most.

The Belgian team was quite surprised to find much larger efficiency gains at the larger micro-level, and this encouraged them to take their research to the next level.

That’s when Belarouci and his research colleagues in Sherbrooke entered the picture. Their role in the collaboration was to replicate the jagged scale structure of a firefly’s lantern and adapt it to an LED device. They did this using a photolithographic process. It involved coating the top of an LED with a light-sensitive material, in this case a type of polymer, and using a laser to create the factory-roof profile.

“We can do this with most LEDs,” said Belarouci, emphasizing the simplicity of the process. “The advantage is that you can add the coating to an existing LED. You don’t have to redesign the whole thing.”

That they have demonstrated the ability to boost LED efficiency by more than 50 per cent has major implications for a market that’s just finding its stride and a technology already known for being 85 per cent more efficient than conventional incandescent bulbs.

Never mind that LED bulbs last more than 20 times longer and don’t contain mercury, one of the biggest criticisms of compact fluorescent bulbs.

As the New York Times reported this week, prices for LED lights are falling and growth is picking up. It cited the fact that LED technology, despite higher retail prices, accounted for 20 per cent of lighting revenues at Philips last year, and that LEDs are expected to outsell incandescent lights in Canada and the United States in 2014, according to technology research firm IMS Research.

By 2016, IMS predicts shipment of LED bulbs for use in standard residential sockets will hit 370 million units. That’s more than 10 times the shipments reported in 2012.

As for the firefly-inspired coating, the researchers figure that modifying existing LED manufacturing techniques to incorporate the light-boosting layer are achievable and could lead to even better energy savings from LED lights within the next few years.

Has the research caught the attention of industry? “So far we haven’t been contacted,” Belarouci said.

It’s only a matter of time.

And it’s not just LEDs that could benefit from this discovery. “You could use the same kind of concept to improve photovoltaic cells,” he said. In other words, solar cells with the coating could potentially absorb more sunlight and produce more electricity per cell.

It’s something to think about the next time you spot a firefly, or, if you prefer, fairies with magic dust.

Tyler Hamilton, author of Mad Like Tesla, writes weekly about green energy and clean technologies.

100-watt LED bulbs occupy the spotlight (get it, spotlight?) at LightFair show

LightFair International kicks off today so expect a slew of announcements around advances in solid-state lighting and lighting automation technologies, particularly an LED replacement for the coveted 100-watt incandescent light bulb. This morning, San Jose-based Switch Lighting has announced a soon-to-be-available (late 2012) LED light bulb that is, in fact, equivalent in light output to a 100-watt incandescent bulb. Now, it will likely cost you about $50 — for now — but that price will come down. In two years, expect your local Home Depot to be heavily stocked with these babies, or some other version. Already, your local HD is likely carrying Philips’ 60-watt equivalent LED — the one with the yellow, space-age casing. I’ve been testing one out in my house and I have to tell you, I love the light. It’s warm, bright, and like all LEDs can be dimmed with no problems.

These bulbs are also getting smarter. Check out Katie Fehrenbacher’s story on Earth2Tech for an idea of what will be on display at the show, such as “networked light bulbs” and remotely controlled Wi-Fi-enabled bulbs.

Now, I do have some concerns — well, not concerns, but let’s call them queries — regarding these bulbs. First, they’re really heavy, so I wonder from a lifecycle perspective how much the added weight affects the carbon footprint of transporting these devices and how that balances off against the gains in light efficiency and bulb longevity. Also, I wonder about the economics of making and supplying these devices, and how that will prevent the bulbs from becoming as affordable as existing incandescents. One of the things that really killed telecommunications suppliers such as Nortel back in the early 2000s was that their product was getting so good they were running harder just to keep up. A new product would effectively replace 10 previous products, so unless you could charge 10 times more for that product you were losing revenues unless you gained more market share. Makers of incandescent bulbs counted on volume to squeeze out a small profit. They counted on bulbs dying out quickly and being replaced to keep the demand continually strong. LEDs, because of their long life (and I mean true long life, compared to those frauds called CFLs that don’t last nearly as long as manufacturer’s claim) really disrupt the business model. So it will be interesting to see how this all turns out.

IKEA to phase out incandescent light bulbs in Canada by Jan. 1, 2011

Swedish furniture goliath IKEA has become the first major retailer in Canada to commit to an all-out phaseout of incandescent light bulbs in 2011, a year ahead of a federal ban on the sale of low-efficiency light bulbs. In fact, IKEA said it will stop selling the bulbs by Jan. 1, 2011, about half a year from now. The retailer will focus sales on compact fluorescent, halogen and increasingly LED lighting options. “Clearly, Thomas Edison’s incandescent light bulb discovery was a landmark 19th century invention,” the company’s press release states. “But times have changed. New discoveries prevail.”


When new energy-efficient technology merely encourages waste

Got an interesting package in the mail yesterday from lighting giant Sylvania, which is introducing a new line of LED-lit products. One is a bottle stopper — you know, those plastic corks you use to store an opened a bottle of wine? But this isn’t just any bottle stopper. Moulded within are two watch batteries that power an LED light that changes colors. The idea is that when you have guests over, you can impress them by lighting up the bottle of wine at the centre of the table. They also have drink coasters and place mats that do the same, creating a light show on the dining room table.

This wouldn’t be possible without LED efficiency. But it also shouldn’t be possible. It’s pointless. It merely encourages more waste. The batteries in most cases can’t be replaced. The batteries run out after 60 hours of use, after which most people will be inclined to chuck the item in the garbage.

This is a prime example of new energy-efficient technology enabling more consumption, more waste. “While seemingly perverse, improvements in energy efficiency result in more of the good being consumed – not less,” said Jeff Rubin in 2007 when he was chief economist at CIBC World Markets. He cited the Khazzoom-Brookes postulate, which argues that “as improvements in energy efficiency lower the cost effective cost of energy relative to what otherwise would have prevailed, the resulting substitution and income effects that flow from any price change result in more of the good being consumed.”

The battery-powered LED bottle stopper and coasters may be small examples of the Khazzoom-Brookes postulate in action, but they all add up. It warns us that technology alone won’t save the day, and in some cases can set us back.