In the beginning there was the candle. Then in 1880, Thomas Edison patented his cotton filament incandescent light bulb. He converted to longer lasting tungsten in 1911, and not much has changed since. 

The familiar 100-watt incandescent light bulb is being phased out under the Energy Independence and Security Act signed in 2007 by President Bush. The law does not ban incandescent bulbs, but it sets efficiency standards the old bulbs cannot meet. That has led to a plethora of new choices for light bulbs.

Baking bulbs for long life 

Engineers at GE’s Nela Park research center in East Cleveland are testing one lighting option. Jim Reginelli bakes a rack of LED lights in an oven the size of a fridge.

“This chamber here to the right is what we call our EHTOL, or extreme high temperature operating life condition,” says Reginelli. “So this is really stressing the component and this will really tell us when the end of life will occur for the LED.” 

Their stress tests are an important consideration for a bulb that retails at $27. They say it will easily glow for 25,000 hours, or 23 years of average use.

From commercial to consumer 

LEDs or Light Emitting Diodes are not new. They are the little red lights inside computers and old calculators. You might ask when will we see LEDs in other uses.

Reginelli says today, if you drive up Noble Road in front of Nela Park, the entire street is lit by GE’s cobra head LED streetlight. Beginning about 10 years ago, they have been used in everything from traffic signals to tail lights because of their long lifespan.

Lead engineer Glenn Kuenzler says developing LED technology for a fickle light bulb-buying public is more of a challenge. In the design, they needed a thermal solution that did not interfere with the optical solution.

Looks like a light bulb 

Edison’s light bulb had four basic elements. The GE team crammed 90 components into its new LED light bulb: nine diodes, circuits, even a transformer converting A/C to D/C. Fins help cool the electronics nestled in the bulb’s base. The egg-shaped glass diffuser spreads the light around evenly. 

Design engineer David Dudik’s job was making it look like an old fashioned light bulb.

“So as we added these heat fins,” says Dudik, “the shape of the diffuser changed to accommodate it, and then once we got to a design point where we felt the reliability was going to be acceptable, we started to try and shape the lamp to make it look as close to an incandescent shape as possible.” 

In other words, no spiraling tubes like you see with compact fluorescent bulbs. 

While their 40-watt replacement is already on store shelves, the five members of the LED team at GE’s Nela Park are working on higher watt LED light bulbs. Lead engineer Kuenzler feels his team is up to the challenge. The disciplines they work with are thermals, optics, electronics, and overall mechanical integration as well as aesthetics.

“There’s a lot of competing factors,” says Kuenzler. “How do we put a product on the market that meets everybody’s expectations and meets their cost expectations at the same time?” 

Changing light bulbs 

In accordance with the law going into effect this month, GE no longer makes standard 100 watt incandescent bulbs. 

Its new LEDs are just one of many choices in the lighting aisle, where you’ll see dozens of flavors of compact fluorescent and halogens from many brands.   

After 100 years, technology and the world-wide push for energy efficiency is truly changing the light bulb.