Shedding light on LEDs

Posted 17 March 2016 1:54 PM by admin

Did you know that the incandescent light bulb invented by Thomas Edison in the late 19th century and patented in its current form by General Electric in 1906, loses 90 percent of its energy in heat? In other words, only 10 percent of the electricity is used to create visible light.

In 2007 Congress passed legislation to effectively ban the incandescent bulb by raising the standards of efficiency. In doing so, they created a race to innovate, as well as a political firestorm. Europe and other countries around the world are also taking similar steps to phase out the outdated and inefficient bulbs.

Before LED’s

We are all familiar with the first attempt at replacing the traditional light bulb known as the Compact Fluorescent Lamp or CFL. Those twisted crazy looking bulbs use up to one third less energy than an incandescent bulb and can save more than five times their purchase price in electricity costs over the life of a single bulb. Invented in 1976 and initially expensive, the costs of these bulbs has dropped significantly since they became commercially available in the 1990’s. Unfortunately the quality of the light from CFL’s, their failure to mimic the warm full range spectrum of incandescents, the fact that they take time to warm up and are not dimable, has left many consumers unimpressed. Add to this recycling problems due to mercury present in the product, inconsistency of performance over time - bulbs have been known to grow dimmer with added use - and you have a light solution that is transitional at best.

Innovate and Illuminate

The real solution appears to be the LED. Light Emitting Diodes use semiconductor chips like those found in your computer. But, instead of turning electricity into information, LED’s turn energy into photons or light. The first visible LED’s developed by GE in the early 60’s emitted low intensity red light. Their initial application was in clock radios and as replacements for indicator bulbs on remote controls and other consumer electronic products. Just as Moore’s law predicted that the number of transistors on a single chip would double every 18 to 24 months resulting in more powerful computers with increased memory capacity at less cost, Dr. Roland Haitz, a scientist with Agilent Technologies, forecast an increase by a factor of 20 in the amount of light produced by LED’s, while the cost per lumen, or useful light, would fall by a factor of 10 every 36 months. In both these cases efficiencies were realized through iterative improvements in the manufacturing process and supporting technologies. As LED’s improved they have been employed in any number of products from airplane lighting to traffic lights, to computer and smartphone displays. But the true promise of Dr. Haitz prediction of LED efficiency and light output would start a race to create an affordable product that could match the light of the inefficient but very popular incandescent bulb.

Companies who make conventional light bulbs, such as Sylvania, Phillips, General Electric, as well as start ups like Cree,  SunSun Lighting and Switch, have spent millions on the research and development of LED’s that will avoid the disastrous fate of the CFL. Phillips and Cree, who appear to have the lead currently, had to overcome a number of complex technical hurtles. Of course the two big issues for consumers are cost and the quality of the light itself. What these companies found was that by combining diodes of different colors across the light spectrum, LED bulbs can produce light equal to or better than incandescent bulbs. These bulbs can also be programmed to alter the light in a room as the natural light changes. As for cost, the very first LED’s developed cost nearly $200. When these bulbs first became available in hardware stores in the early 2000’s they were priced in the $30 to $40 range and available in wattages equivalent to less than the popular 60, 75 and 100 watt bulbs. But, over the last two years things have changed and prices have dropped precipitously. In 2013 Cree introduced both a 40 and 60 watt equivalent LED bulb for under $10. While this is considered the sweet spot for luring potential customers, it is still more expensive than traditional bulbs. The price should continue to drop as more companies, including several in China, introduce their own products. Early adoption of the LED bulbs are expected in the US and Europe with the far east and China to follow.

Bottom line

Thomas Edison’s lightbulb is in decline. LED’s are more efficient, radiating very little heat, and will last anywhere from 35,000, to 50,000 hours compared with the 1,000 to 2,000 hours of light generated by an incandescent bulb. Standard bulbs as we have known them now for more than 100 years are being phased out. This despite a libertarian groundswell to keep the old product on store shelves, due to the greater up-front cost to consumers. However, It should be remembered that when Edison’s bulbs first appeared on the market a single bulb cost 44 cents. That’s more than $10 adjusted for inflation. Now that LED’s are under $10 consumers may finally be able to see the return on their investment, not just on the cost of the bulb, but on the benefits to the environment. After all, it is estimated that the amount of energy used world wide for lighting would be cut in half using LED’s, eliminating more that 200 million tons of carbon emissions per year.  Now, that’s innovation!

         

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