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LED2011_Abs - Alex Grozdic Connor Mattheyvs Sarah Quirk...

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Unformatted text preview: Alex Grozdic Connor Mattheyvs Sarah Quirk Light-Emitting Diodes Across the globe, many people have a growing concern about energy usage and green technology. LEDS, light-emitting diodes, are on the fast track to becoming to worlds most efficient lighting source available. LEDs use less energy and have a lifespan that far g exceeds the traditional incandescent light bulb. Other advantages include dimming, » speed, slow failure, and shock resistance. LEDs can be found in stadium displays, traffic lights, emergency lighting, automobile lighting, digital clock displays, and electronic “ displays. Also, due to the relatively low cost of manufacturing, LEDs can provide temporary light and be used in glow sticks and other such devices. These are LED : technologies that are familiar and already in-place today, yet the industry IS still growmg at a rapid rate and improvements will continue to be made. To explain how an LED works, one must first understand diodes. A diode is a very , simple semiconductor device. It is used to allow electric current to pass through in one direction, but not the other LEDs work by creating a p—n junction, where current flowsE from anodes to cathodes. When an electron reaches a hole it transitions to a lower energy level. This transition causes energy to be released 1n the form of a photon. The photon’ s wavelength, and therefore color, depends on the size of the band gap in the p—n junction. Nick Holonyak Jr. developed the first practical LED in 1962. The first LEDs emitted only visual red light and were used as indicator lights in electronic devices. Today’s LEDS, however, can emit any color of visual light, they can also be flashing, bi-color, tri—color, or RGB. In addition, LEDs can also be used for ultraviolet and infrared lights depending on the application. Future outlooks hope to broaden the use of LEDs as a regular lighting source. LED light bulbs consist of a cluster of up to 180 LEDs per encased bulb. The cost of LED light E blubs is steadily declining which should provide a higher usage rate. Many manufacturing improvements have resulted in less failures and a decreased learning curve. As seen above, LED technology consists of a broad range of material. We will limit our presentation to three main focus areas: LED applications, microfabrication of LEDS, and future LED technology. Several current LED applications are listed above, but our , presentation will cover these more in-depth. Microfabrication Is a process that E miniaturizes structures. Recently, this process has been applied to creating LEDs. Finally, research 1n creating better and more efficient LEDs IS happening all round us. The future for LEDs may be unknown, but our presentation will provide insight to current LED ‘ technology. ...
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