As Costs Plummet, LED Use Soars

Wayne Yamaguchi never planned to start his own light emitting diode (LED)-based business. A former Hewlett-Packard engineer, Yamaguchi says LEDs were always more of a diversion than a long-range goal. But that was before he began pestering sales reps to discuss new LED technologies, before he began packing his desk drawers full of LED samples, and before he began staying up all night writing LED drivers for flashlights.

"It was just a hobby," explains Yamaguchi, who now heads Yamaguchi Consulting, which specializes in the creation of software drivers for LED-based products. "I never made a decision to launch a business; it just turned out that way."

Yamaguchi isn't the only engineer who's been swept up in the prevailing LED-based winds. In Design News' recent reader survey of LED technology, approximately 92 percent of respondents said they have used, or plan to use, LEDs in their products. Moreover, their list of applications goes far beyond the traditional lighting industry. Respondents said they've used LEDs in automotive, aerospace, agriculture, defense, gaming, industrial and medical applications, among many others. They've used them in the design of bicycles, cameras and televisions. They've installed LED strips in pontoon boats for foot-level lighting. They've placed them in robots and traffic lights. They've even put them in refrigerators and food service equipment.

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"The ramp-up of LED commercialization is just starting," Yamaguchi says. "They're like calculators were a long time ago. ?When calculators first came out, they were $200 and had four functions. Now you can buy calculators that are far better for 99 cents. It's going to be the same with LEDs."

Low Power Draw Is Key

Design News' survey provides some insight as to why engineers are moving so fast into the LED arena. And while respondents were strong in their support of this emerging technology, they were varied in their reasons.

"There's a combination of factors that are coming together to make LEDs appealing," says Michael Bandel, an electrical engineer with Heatron Corp. who responded to the survey. "The government is pushing it, the technology is getting better and cheaper, and energy efficiency is becoming more important."

Clearly, declining costs play a big role in their decisions. The technology - which calls on semiconductor chips to release energy as photons of light - has been in existence for nearly 50 years but has only recently reached a price point that makes it viable for widespread use.

Design News' LED survey bears out the importance of the rapidly declining costs. One-third of those polled said that they are now using LEDs because "the cost came down."

Moreover, costs are expected to continue to decline, and many respondents who haven't yet used the technology said they're preparing to jump on board when the price drops to the right level. If prices follow an oft-quoted economic rule called Haitz's Law (which predicts that LED cost per lumen falls by a factor of 10 every decade, while light generated per package rises by a factor of 20), many expect to reach that decision point in the coming decade.

"The big appeal is the performance versus the price," Bandel says. "Ten years ago, the prices were very high and the performance was very low. But with each tick of the clock, they're getting better."

Still, Design News readers said the price/performance curve pales in comparison to the importance of such parameters as longer life and lower power draw. Several who spoke to Design News cited LED life expectancies of as much as 60,000 hours, which translates to almost seven consecutive years of use. Others cited the high
lumen/Watt ratios as a primary reason for consideration.

The Design News survey showed those advantages were critically important to the new breed of LED users. Asked, "What drew you to the technology," 79.6 percent cited longer life. At the same time, 77.7 percent said they wanted the lower power draw and 50 percent said they were attracted to the technology's environmental advantages (respondents were encouraged to cite more than one reason).

"I need the most efficient, state-of-the-art lighting system on the planet," says survey respondent Wayne Leonardi, founder of WTLS Services. "And that appears to be LEDs."

Heat, Drivers Top List of Concerns

Survey respondents, however, universally indicated that it wasn't always easy to integrate LEDs into their products. Many cited concerns with heat and software drivers. Others said that costs haven't dropped enough yet. A few said they worried about design complexity and about their own lack of understanding of this emerging technology.

Still, about 43 percent of respondents said they consider the choice of their LED driver to be "very important" and 32 percent described LED drivers as "important." Only 16 percent considered drivers to be unimportant, while about 9 percent said they simply don't understand LED drivers.

Yamaguchi, who specializes in creating drivers for LED flashlights, says that drivers have a variety of important roles, not the least of which is the prevention of heat. "A lot of LED flashlights have multi-levels and people don't always keep them on the high setting," Yamaguchi explains. "That way, they don't always get hot."

Still, heat came off as a big concern for the survey's respondents. Approximately 57 percent of them considered it an issue.

"Heat is always a major factor," Yamaguchi says. "LEDs radiate all their heat into a heat sink, whereas incandescents
radiate it out as infrared."

Among those who considered heat to be an important issue, most plan to opt for a heat sink to help deal with it. Forty-six percent said they will employ a heat sink, while 38 percent said they will deal with heat by selecting the right driver. Others said they've used, or plan to use, fans and synthetic air jets as a way to dissipate heat.

"People have rightly concluded that if LEDs are designed properly and heat-sinked properly, they can last 50,000 hours or longer," Bandel points out.

Applications Abound

One area where readers were split was dimming capability. About 46 percent of the respondents said dimming capability was unimportant. Among the remainder, 30 percent said it was important, while 24 percent cited it as very important.

"Everybody says they want dimming," Bandel says. "The problem is, nobody wants to pay for it."

Respondents who want dimming tended to be more in the lighting or construction businesses. Engineers pointed out that dimming is particularly important in construction of new buildings and offices, where builders typically keep an eye on future trends.

 While lighting (39%) was the most common application for future LEDs, however, uses for the technology varied broadly, with no single application standing out. Industrial controls and automation equipment (32%), consumer electronics (28%), and automotive (21%) were among the most common applications for LEDs. Readers also cited aerospace (12%), medical (12%), signage (12%), and defense (11%).

In general, however, Design News readers showed they are bullish on the future of LEDs, even if they don't use them today. "Their application and usage will take off ?for sure, just based on energy efficiency alone," Bandel says.

Yamaguchi, who started out making drivers for LED flashlights, adds that he has seen the trend spread to bicycle lights, helmet lights, aquarium lights and a multitude of other applications. "LEDs are still in their infancy," he concludes. "They're more expensive right now, but in 10 years they're going to be more cost competitive."