As the future gets dimmer for traditional incandescent light bulbs, and compact fluorescents (CFLs) fall out of favor due to their toxic mercury component, light-emitting diodes, or LEDs, are beginning to come on strong. LEDs, which are clusters of small bulbs that come in many shapes and sizes, last five times longer than CFLs and 40 times longer than incandescents and use much less energy. (Media credit/Geoffrey Landis)

Just a decade ago, incandescent bulbs were just about the only game in town, despite their inefficient use of electricity to generate light and their primitive technology that had not changed since being invented some 125 years ago. But now that is all changing fast, with phase-outs of incandescents going on in Australia, Brazil, Venezuela, Switzerland and the European Union, with Argentina, Russia, Canada and the U.S. following suit shortly. The U.S. passed legislation in 2007 to increase the efficiency of light bulbs sold in the U.S. by 25 percent or more by 2014, and then by as much as 60 percent more by 2020.

For decades, those concerned with energy savings have been touting the benefits of compact fluorescent lamps (CFLs) over incandescents. CFLs use only one-fifth of the electricity of incandescents to generate the same amount of light, and they can last six to 10 times longer. But CFLs’ cooler color and inability to be dimmed have made them less desirable. Another hindrance to the widespread adoption of CFLs has been their higher cost (though most consumers would save plenty in energy costs over the life of a bulb). Also, CFLs contain mercury, a dangerous neurotoxin that is released when the bulbs break. And once CFLs do burn out they must be disposed of properly to avoid releasing mercury into the environment.

Given the issues with CFLs, LEDs (short for light emitting diodes) are beginning to come on strong. These highly efficient bulbs don’t generate heat like incandescents (which helps to keep air conditioning costs down as well) and can last five times longer than CFLs and 40 times longer than incandescents. Tiny LED bulbs have been around for years in specialized applications (such as stadium scoreboards), but lighting engineers got the idea to cluster them and use reflective casings to harness and concentrate their light for residential use. In recognition of the LED’s potential, the U.S. Department of Energy (DOE) set up a special “solid-state” (LED) lighting R&D program to hasten the advance of the technology.

In comparing the total cost to run three different types of 60-watt equivalent bulbs for 50,000 hours (factoring in the cost of the both bulbs and electricity), the EarthEasy website found that LEDs would cost $95.95, CFLs $159.75 and incandescents $652.50. The 42 incandescent bulbs tested used up to 3,000 kilowatt hours of electricity compared to 700 and 300 for CFLs and LEDs respectively. However, despite the savings most consumers are loath to spend $35 and up for an LED bulb (even though it will save more than $500 in the long run) when a traditional incandescent bulb right next to it on the shelf costs $1.

There are other newer technologies in the works. Seattle-based Vu1 now sells highly efficient bulbs based on its Electron Stimulated Luminescence (ESL) technology, whereby accelerated electrons stimulate a phosphor coating on the inside of the bulb, making the surface glow. One of Vu1’s 65-watt equivalent bulbs retails for under $20 and uses a similar amount of energy as an equivalent CFL. And incandescents aren’t out of the efficient lighting race altogether just yet. Top bulb makers recently released new versions that use as much as a third less electricity to operate (complying with 2012’s new federal standards) and are promising newer models still that will run on even less energy.

CONTACTS: DOE Solid-State Lighting Program, www1.eere.energy.gov/buildings/ssl/; EarthEasy, www.eartheasy.com; Vu1 Corporation, www.vu1corporation.com.

There’s light, and there’s light. In the world of optical electronics, the difference between blue-green, red and yellow is equal to the beautiful variety that, say, Beethoven imagined in a symphony, or the stunning complexity that Einstein pictured shaping the Universe.

For Martin Schubert, a 25-year-old doctoral student at Rensselaer Polytechnic Institute, discovering a new way of looking at the LED, or Light-Emitting Diode, is going to change the way the world sees. That accomplishment earned him the $30,000 Lemelson-Rensselaer Prize for 2008.

Precisely, Schubert discovered that ordinary LEDs produce polarized light – a lot of it. That means more energy-efficient, compact displays for everyday tech objects. Before Schubert’s find, normal LEDs had never been known to produce polarized light. Schubert, on a hunch, decided to take readings from the sides of diodes, as all other readings were done from the top, and found the previously undetected polarized light literally pouring out. Even senior experts in his field didn’t anticipate that development.

Schubert then created a reflector that directed the light vertically; creating a truly and potentially cheap source of polarized LED.

“Discovering that normal LEDs emitted polarized light at a ratio of 7:1 from the side, that was big moment,” said Schubert. “Shortly afterwards we made a reflector in a certain way so we could use that light. Those were two big moments.”

Why is accessible polarized light with the possibility of cheap manufacture a big deal?
In order to put Schubert’s accomplishment in perspective, an explanation of the way current lighting technology works in such things as laptops is beneficial. In most laptops, the LCD, or Liquid Crystal Display, is sandwiched in, “a stack of thin films,” said Schubert.

First, there’s the source light, which is generally fluorescent and not polarized. From there it goes through a liquid crystal polarizing filter. After that, it goes through a second polarizer, and then the light hits your eyes.

Some of the drawbacks to this method have to do with the lighting source itself, fluorescence, which utilizes highly toxic mercury. Another is that a significant amount of energy is needed to create light that is sufficiently bright to penetrate the polarizing filters.

While the some recent LCD displays have utilized LED as source lights, such as the extremely thin LCD on the MacAir and some high definition televisions, a polarizing filter is still required, adding not only to the overall thickness, but energy consumption.

In creating an LED that’s polarized at the source, the filtering layers are bypassed, leading to greater energy efficiency and a potentially razor-thin display.

“You lose at least 50% intensity starting with unpolarized light,” said Schubert. “Basically, that’s what motivated me to create a polarized LED. I decided a it would be a great thing to have in LCDs.”

While Schubert’s method isn’t the only way of creating a polarized LED light, it is the cheapest and least labor intensive. The reason has to do with two fundamentally different manufacturing methods.

In order to create a single LED, special crystals are first grown using one of two methods, C-PLANE or M-PLANE.

C-PLANE is currently the industry standard, as growing crystals using the C-PLANE method is faster and lower cost. In order for polarized LEDs using the M-PLANE method to become a reality, the entire manufacturing industry would have to convert to that method – an unlikely possibility, according to Schubert.

“One of my limitations when I first started out was that I couldn’t use that sort of esoteric growth technique. That was a self-imposed limitation,” said Schubert. “I would consider this the first practical way to make polarized LED lighting. You can take what’s being made on assembly line today and just change the chipset.”

And the benefits of readily available polarized LED lighting extend beyond LCD displays.

Schubert cited robotic applications as one example. In trying to teach machines to translate visual data in a way similar to the human eye, polarized light is the holy grail, as it is far easier for robots to interpret. Widely available polarized light could lead to cheaply manufactured robots that have high visual acuity, roaming the halls of, say, a hospital carrying medications or charts.

Schubert’s plans don’t stop with polarized LEDs, either. His plans for the future include researching ways to create LED lights capable of enough power for standard home lighting applications. Currently that is not possible, due to what’s known as, “efficiency droop.”

One of the limitations with LED lighting is that after achieving certain brightness, the power needed to increase the level of light increases by orders of magnitude. So, more power can be given to the LED, but the return in brightness drops quickly to levels that make the power input impractical.

He is also interested in developing more efficient Ultra Violet LEDs, as currently UV LEDs burn out at a rate that hinders their use in widespread applications. Long-life UV LEDs would be beneficial in a plethora of applications, from water sanitation, hospital sterilization, to tanning beds.

If Schubert or other scientists solved the efficiency droop issue and created LEDs for standard household lighting, the power savings are potentially enormous: LEDs use 10 percent of the energy of a standard bulb.

“I saw a statistic that 20 percent of all energy consumed in this country is for lighting. If you increase efficiency by switching over to LEDs, you could shut down hundreds of power plants,” said Schubert. “LEDs are also very long lifetime. They almost never burn out.”

And if Schubert has anything to say about it, you’ll never have to change a light bulb again.