June 1, 2007 Material research scientists have made electroluminescent technology elastic and supple enough to be knitted and incorporated into canvas tent panels. An electric field is produced across the multi-layer structure which releases charged molecules into the panel, when a voltage is applied. Once plugged into A/C or battery power, the panels illuminate and give off visible white light.
Imagine setting up your camping tent, plugging it into a battery and voila!, the inside of your tent lights up. The best part is there are no heavy bulbs to break or carry because the fabric itself gives off the light.
Todd Oswald loves the camping life. He works hard all week and hits the campgrounds on weekends with the family. "It's a time for us to get away from the hustle and bustle," Oswald says. Camping for him could soon be lighter, thanks to electroluminescent, or EL, technology that gives off light from an electrical charge.
Materials research scientists have made EL technology flexible enough to be woven into tent panels. Once the tent is plugged-in to A/C or battery power, the charge releases molecules inside the panel creating light! Eric Bruton, Ph.D., a scientist in St. Louis, explains the system, "What we do is we generate an electric field across the phosphor, which causes the phosphor to emit light."
The military is funding the research hoping to get rid of heavy, breakable bulbs and speed up troop logistics. Workers here use a relatively inexpensive screen-printing process. Patrick Kinlen, Ph.D., the Chief Technology Officer at Crosslink in St. Louis, says, "What we do is build a multi-layer structure that emits light when we apply a voltage."
Once plugged in, the panels give off white light so you can see. The fabric is also crushable and bendable, making it easy to pack up and making it "light" on your load. Oswald thinks it will be a very good thing. He says, "As a backpacker, you're always trying to look for anything that's going to help you lighten your load."
In addition to giving off visible light, the tents can be made to produce infrared light which means that soldiers can use night vision goggles to work inside their tents without giving away their position. The future for this technology includes light-up panels on safety vests for highway workers and joggers, as well as bicycle helmets.
BACKGROUND: Materials scientists are developing camping tents that light up on the inside simply by plugging it into a battery. But there are no bulbs of any sort. The fabric itself emits light. Crosslink, a leader in electroactive polymer materials, is developing a crushable, durable, lightweight electroluminescent technology based on polythiophene, a plastic that conducts electricity. It can be made to emit either visible light or infrared light.
ADVANTAGES: The treated fabric panels serve two potential purposes. First, the panels can light the inside of the tent with visible light, replacing the need for traditional bulbs. Second, the technology can also give off infrared light, which is sensitive to heat and invisible to the human eye. The U.S. Army is interested in using the fabric for battlefield tents because soldiers could use their standard issue night vision goggles to read specially treated documents and maps without indicating their position to hostile forces. SuperFlex can also withstand being twisted, punctured, torn or scrunched-up without losing its ability to light up. The military could also use it, for instance, in a foldable map that emits its own infrared light so it can be read in complete darkness using night vision goggles.
ABOUT LEDS: LEDs are essentially tiny light bulbs that fit into an electrical circuit, but they are lit solely by the movement of electrons in a semiconducting material. A diode is the simplest semiconductor device. It is made by bonding a section of a positively-charged material to a section of a negatively-charged material with electrodes on each end so that it only conducts electricity (in the form of free-moving electrons) in one direction whenever a voltage is applied to the diode. Electrons move in a series of fixed orbits around the nuclei of atoms. Whenever an electron absorbs extra energy from the added voltage, it jumps to a higher orbital, and when it returns to a lower orbital, it emits the extra energy as a photon -- a particle of light. LEDs are specially constructed to emit a large number of photons, unlike ordinary diodes, in which the semiconductor material absorbs most of the light energy before it can be released. LEDs are also housed in a plastic bulb to concentrate the light in a particular direction. Polymer light-emitting diodes emit light when an electric current runs through them.
The Institute of Electrical and Electronics Engineers, Inc., and the Materials Research Society contributed to the information contained in the video portion of this report.