How FIPEL Bulbs Work

Dr. David Carroll, director of the Center for Nanotechnology and Molecular Materials at Wake Forest University, and graduate student Greg Smith (black shirt) look at FIPEL lighting.
Dr. David Carroll, director of the Center for Nanotechnology and Molecular Materials at Wake Forest University, and graduate student Greg Smith (black shirt) look at FIPEL lighting.

Companies sure love their fluorescent office lights; office workers, not as much. These lights may be more energy-efficient than conventional incandescent lights, but they tend to flicker, and give off a weird, unnatural yellow tint that some complain is hard on the eyes. Worse yet, they often emit a continuous buzzing sound, which can become so irksome and enervating that, at some point, you imagine yourself as the scientist who was accidentally transformed into a human-insect hybrid in the 1958 horror film "The Fly."

People have been putting up with the visual and aural shortcomings of fluorescent lights for more than 60 years, ever since fixtures using the technology started to become widespread after World War II. A 1947 article in Popular Mechanics magazine, for example, compared their sound to "a bee in flight in the quiet of a bedroom" and cautioned homeowners to install them in places such as attics and basements, where they wouldn't cause sleepers to toss and turn fitfully [source: Brown]. While more recent fluorescent tubes don't hum quite as much as their predecessors did, they still make enough noise to be bedeviling.

But there's a new bulb on the horizon, which lasts longer than a fluorescent light and is quiet; uses less energy than an incandescent bulb and or even a compact fluorescent light (CFL); and doesn't emit the bluish light of the CFL or the light emitting diode (LED) bulb. Researchers at Wake Forest University in North Carolina and Trinity College in Ireland have developed a new sort of light fixture based on field-induced polymer electroluminescent technology, also known as FIPEL. They're already working with a company called CeeLite to manufacture FIPEL lights and hope to have them on the consumer market by the end of 2013 [source: Neal, Spector]

In this article, we'll explain how FIPEL lighting works and why many are seeing it as a potentially enormous advance.

Why Fluorescent Lights Are So Annoying

General Electric first introduced fluorescent lamps at the 1939 New York World's Fair. They were immediately a hit with industries because the lamps had a long life and therefore cost less to install and maintain. But they weren't so popular with ordinary people because of that darn light buzz and the harsh light the lamps emitted [source: Adams]. Where does that come from?

Fluorescent lights basically are tubes filed with a mixture of an inert gas, such as argon, and some mercury. When electrical current is pumped into the tube, the electrons collide with the mercury atoms, exciting them and causing them to release ultraviolet light [source: Adams]. Material called phosphors, which lines the inside of the tube, converts the ultraviolet to visible light. The problem is that if left to its own devices, the current would keep rising in the tube to dangerous levels, until it tripped the circuit breaker in your house. A device called a ballast keeps that from happening, by creating a magnetic field that obstructs the flow of current just enough to keep you safe [source: Adams].

Particularly in older fluorescent light fixtures, the ballast's magnetic field has a tendency to cause an effect called magnetostriction. That means that the magnetic field actually squeezes the ballast's core, altering its shape slightly. That makes your fluorescent fixture squeak over and over, about 120 times per second [source: Adams]. You probably couldn't design an everyday technology to be more annoying. That's why it took a whole new technology to get around it.

A New Type of Light Bulb

Wake Forest University post-doctoral researcher Wanyi Nie with the FIPEL technology.
Wake Forest University post-doctoral researcher Wanyi Nie with the FIPEL technology.

Researchers at Wake Forest and Trinity didn't actually invent FIPEL technology-- the earliest paper on it seems to have been published by Austrian researchers in 1992 -- but their device is the first to turn it into a viable light source [source: Dillow, Grem, et al].

Instead of mercury or the filaments in old-fashioned incandescent bulbs, FIPEL lights contain multiple layers of polymers – plastic—imbued with an iridium compound and a small number of carbon nanotubes. The latter are cylindrical structures, built in laboratories that are as minuscule as 1/10,000th the diameter of a human hair! Compared to conventional materials, these nanomaterials have a lot of novel characteristics, such as increased strength, chemical reactivity and/or conductivity [source: European Commission]. When electrical current flows into the FIPEL tube, it stimulates it to produce light just as electrical current passing through mercury in a fluorescent tube does. That energy is filtered through the polymers to create light [sources: Dillow, Electronics Weekly].

Energywise, the FIPEL light is twice as energy-efficient as a CFL, about the same as a LED. But it doesn't have any caustic chemicals like the CFL which contains a small amount of mercury. And because it is plastic, the FIPEL is easy to recycle. The bulb has a lifetime of 25,000 to 50,000 hours, about the same as LED. Wake Forest physics professor David Carroll, who's the inventor, said he's had a bulb burning in his lab for a decade [source: Neal, Spector].

Why FIPEL Lights May Be the Future

Researchers say that FIPEL lights can be manufactured to produce just about any color of visible light in the solar spectrum. As Carroll told the BBC, FIPEL lights are vastly superior in that regard to CFLs. "[CFLs] have a bluish, harsh tint to them," Carroll explained. "It is not really accommodating to the human eye; people complain of headaches and the reason is the spectral content of that light doesn't match the Sun -- our device can match the solar spectrum perfectly.

"We are brighter than one of these curlicue bulbs and I can give you any tint to that white light that you want," Carroll added [source: McGrath].

Additionally, because they're made of plastic, FIPEL lights can be molded into a wide variety of shapes -- from bulbs that fit into the old sockets designed for incandescent bulbs to large sheets or panels that could fit into the spaces above ceiling tiles and behind walls, so that a soft, unobtrusive light can be evenly spread throughout a room [source: Dillow].

As for cost, a management consultant for CeeLite said the manufactured FIPEL bulbs should cost less than LEDs but a little more than CFLs [source: Spector].

One critic questioned whether in fact FIPEL was actually a breakthrough, since warm white LEDs are already available (without the bluish tint) and CFLs have only a minuscule amount of mercury, too little to be much of an environmental hazard [source: Holloway]. But most of the reaction has been positive. The Web site Engadget, for example, called FIPEL the "super-bulb" [source: Cooper].

Author's Note: How FIPEL Bulbs Work

Fluorescent light has a lot of strange associations for me. When I was a boy in the 1960s, I used to spend a lot of time in the pet department of Woolworth's five-and-ten store, admiring the colorful tropical fish and the variety of turtles, chameleons and other tiny reptilian creatures that spent their brief lives in tiny glass terrariums, surrounded by plastic plants and bathed in eerie, flickering fluorescent light. Years later, when I worked in a windowless corner of a newspaper office, I spent long days and nights bathed in the same sort of unnatural glow by the humming, flickering ceiling lights. I finally realized how those reptiles felt.

Related Articles


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  • Brown, Sam. "Light Up." Popular Mechanics. July 1947. (Feb. 3, 2013)
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