LED Lighting Technology By: Dan Kaser 9/17/2007

What Are LED’s? LED is an acronym for Light Emitting Diode Instead of a filament they use a semiconductor diode which emits narrow- spectrum light. Depending on the composition & condition of the semiconducting material used (Silicone, germanium), they come in either Infrared for sensing heat, Visible for every day use, or Near-Ultraviolet for spotting stains at a crime- scene. An LED consists of a chip of semiconducting material that has been “doped” with impurities in order to create a p-n junction. A p-n junction is basically a junction between an anode and a cathode. Current flows easily from the p-side to the n-side, but never in the reverse order. The wavelength and color of the LED depends on the band-gap energy of the materials forming the p-n junction.

Where do we see LED’s? Everywhere!!

Current uses of LED’s Status indicators on all sorts of equipment: your cell phone, computer, monitor, stereo Traffic lights Architectural lighting Exit signs Motorcycle and bicycle lights Railroad crossing signals Flashlights Emergency vehicle lighting Message displays at airports, railways, bus stations, trams, trolleys and ferries Military and Tactical missions utilize red and/or yellow lights to retain night vision. Movement sensors LCD backlighting in televisions Christmas Lights Lanterns

LED’s Vs. Incandescent’s Incandescent Positives Cheap to manufacture & buy Easier to come by Generally stronger light output Better for seeing through Fog and Smoke Negatives VERY breakable Horrible patterns in light Hot burning Heavy on battery consumption Short lifespan Yellowish color filters out anything with yellow in it, IE: White looks yellow, yellow doesn’t show, red looks brown, green looks black. LED Positives Virtually indestructible 100,000 hour lifespan Low energy consumption Symmetrical beam with little-to-no artifacts Cheap to manufacture Available in a multitude of colors without requiring a filter. Pure white light means no color will be filtered out. Low functioning temperature Negatives Less potential output (for now) Slightly more expensive to purchase

Potential uses in the future LED’s are already being used in tail-lights for cars, and some companies like Lexus are experimenting with LED headlights Home lighting: Imagine a “light-bulb” with 100,000 constant hours of use. In other words: 100,000 hours/24 hours a day = 4,166 days 4,166 days/365 days a year = 11.4 years. Not only will the light bulb last for 11.4 years, but it will also require much less current than a traditional light-bulb. If one LED-light bulb requires half the energy of one Incandescent light-bulb, we may not have to suffer through rolling blackouts ever again! LED’s are already getting brighter. Here is an example of one of the most recent LED’s to hit the market titled the “Luxeon Rebel”. It is both twice as bright, and uses half the current of it’s predecessor of only 2 years. Technology will eventually dictate that LED’s are the light source of the future.

How will this affect the business world? With the horizons of LED technology broadening, many light manufacturer’s are putting their top scientists to work: Maglite, for instance, always made Incandescent lights, but have recently begun creating drop-in LED modules for their incandescent torches. If one car company comes out with LED headlights that manage to function at a higher efficiency and also increase output, it is inevitable that all other car companies will follow. Nobody likes a burnt out headlight! Energy is an expensive commodity! The more money we can save on energy, the more money we can spend on more important business aspects. One office building that solely uses LED bulbs could save thousands a year in Energy use alone. When the sun explodes we won’t be able to make anymore energy and we will have to rely on LED’s and their efficiency to find food in the pitch black. Impact of LED’s on the world of Business

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