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The Technical and Cost Challenges Facing LED Bulbs

By Wesley Fenlon

A new 3M LED bulb design comes up with a way to dissipate heat without a chunky heatsink.

Compact fluorescent bulbs were supposed to wipe cheap, hot, inefficient incandescents off the map. They were the lightbulbs of the future. Until, well, we got a taste of the downsides: longer warm-ups, higher prices, and dangerous mercury. It's all well and good to make a more energy efficient light, but when it's a landfill hazard and not great for our skin, it's time to look for a new technology. Light-emitting diodes are expected to be that technology, but LED bulbs have issues of their own, too.

Instapaper creator Marco Arment has written about the downsides of LEDs (brightness, price, light distribution) but also the advantages (efficiency, durability, eco-friendliness). His most recent blog post about the bulbs recommended the Lighting Science and $50 Philips L-Prize, which is a crazy-expensive but very efficient, very bright LED bulb.

Very bright for a 60 watt-equivalent bulb, anyway. One of the reasons we haven't seen LEDs sweep incandescents off Wal-Mart shelves is their overall brightness. The Philips draws less than 10 watts of power to output as much light as a regular 60 watt incandescent, which makes it similar to most LED bulbs on the market. The technology for 100 watt-equivalent bulbs hasn't quite proven itself yet, and before they do, bulb designers are going to have to get creative with heat dissipation.

A Kickstarter project for an LED bulb called LIFX has come under fire for making questionably realistic promises. In addition to the business headaches of releasing this kind of product, the specifications sound too good to be true: it's a multi-color LED bulb with a built-in wireless chip that enables remote control from a smartphone. Can the bulb actually deliver quality light, for about $50, without overheating? The mockup design is more heatsink than bulb. For LEDs to really take off, we'll need dramatically cooler components or a smarter way to dissipate heat.

The latter seems more likely. 3M, for example, has developed a bulb that looks more like a classic incandescent than most LED bulbs. Vents in the bulb emit heat, while "light guide" technology, something like LED TV edge lighting, evenly distributes the produced light around the entire face of the bulb. Theoretically this will produce even, omnidirectional light with no heatsink, though it's still a 60W replacement. And apparently it's completely cool to the touch.

At $25, it's a much more practical replacement than a number of other LED bulbs on the market. If heat is the bottleneck holding back a flood of cheap LED bulbs and more powerful 100 watt equivalents, 3M's design might be the breakthrough solution.