Evolution of Light Emitting Diodes (LED)
Evolution of Light Emitting Diode (LED)
Light Emitting Diode (LED) technology is impacting every facet of our daily lives. From opening our eyes in the morning as we turn off the digital light alarm clock to closing our eyes at night to the glow of street lights illuminating the road or parking lot. LED lighting is now the new standard in illumination. The electroluminescence phenomenon discovered by British experimenter H. J. Round in 1907, advanced into the first LED by Oleg Losev in 1927, evolved into the first visible-spectrum (red) LED in 1962 by Nick Holonyak, Jr. and progressed by T. P Pearsall into the first high-brightness LED in 1976 continues to evolve at an incredible rate. The contribution of these scientist and thousands more are impacting our planet in ways that go well beyond illumination.
Benefits of LED Technology
The transition to LED technology is supported by the many benefits LED lighting provides. As global energy consumption continues to increase and the cost of delivering energy to consumers also increases the value add provided by LED technology is enormous. Advantages LEDs have over other forms of lighting such as incandescent, fluorescent and sodium lights are numerous and include:
• Lower energy consumption – saving money and reducing environmental pollution
• Longer lifetime – reducing replacement and maintenance cost
• More robust structure – allows operation in environments where harsh conditions exist
• Smaller size – opportunities to install lighting in locations previously unavailable
• Faster switching -delivering instant light once the switch is turned on.
What New Developments are on the Horizon?
Materials technologies are constantly evolving. The application of quantum dots is being introduced that allow LEDs to create almost any color on the CIE diagram providing more color options and better rendering compared to white light LEDs. Someday quantum dot applications may be available in LED televisions but before that occurs challenges associated with quantum dots stability which under prolonged radiation must be resolved.
Further developments in miniaturization continue! How small is small? Researchers at the University of Washington synthesized a LED that is three atoms thick, 10,000 times smaller than a human hair. The proposed purpose is to improve the capabilities of optical communication and nano lasers.
At the other end of the spectrum is LED lighting that is bigger and brighter. Super sizing has its own issues most notably dealing with the generation of significant amounts of heat. To overcome the heat issue, which degrades and destroys the diodes, sophisticated heat sinks are used. Today, high powered LEDs (HPLEDs) are incorporated into floodlights and drop lights that produce light output measured in thousands of lumens making it possible to light large space locations including bridges, warehouses, commercial properties and industrial operations.
Where LED technology will be in twenty years requires a crystal ball but according to Haitz’s law, which states that every decade, the cost per lumen (unit of useful light emitted) falls by a factor of 10, and the amount of light generated per LED package increases by a factor of 20, for a given wavelength (color) of light, the future is very bright.