As Costs Plummet, LED Use Soars

WayneYamaguchi never planned to start his own light emitting diode (LED)-basedbusiness. A former Hewlett-Packard engineer, Yamaguchi says LEDs were alwaysmore of a diversion than a long-range goal. But that was before he beganpestering sales reps to discuss new LED technologies, before he began packinghis desk drawers full of LED samples, and before he began staying up all nightwriting LED drivers for flashlights.

"Itwas 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."

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

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

Low Power Draw Is Key

Design News' survey provides someinsight as to why engineers are moving so fast into the LED arena. And whilerespondents were strong in their support of this emerging technology, they werevaried in their reasons.

"There'sa combination of factors that are coming together to make LEDs appealing," saysMichael Bandel, an electrical engineer with Heatron Corp. who responded to thesurvey. "The government ispushing it, the technology is getting better and cheaper, and energy efficiencyis becoming more important."

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

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

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

"Thebig 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 tickof the clock, they're getting better."

Still,Design News readers said theprice/performance curve pales in comparison to the importance of suchparameters as longer life and lower power draw. Several who spoke to Design News cited LED life expectancies of as much as60,000 hours, which translates to almost seven consecutive years of use. Otherscited the high
lumen/Watt ratios as a primary reason for consideration.

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

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

Heat, Drivers Top List of Concerns

Surveyrespondents, however, universally indicated that it wasn't always easy tointegrate LEDs into their products. Many cited concerns with heat and softwaredrivers. Others said that costs haven't dropped enough yet. A few said theyworried about design complexity and about their own lack of understanding ofthis emerging technology.

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

Yamaguchi,who specializes in creating drivers for LED flashlights, says that drivers havea 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 themon the high setting," Yamaguchi explains."That way, they don't always gethot."

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

"Heatis always a major factor," Yamaguchisays. "LEDs radiate all their heat into a heat sink, whereas incandescents
radiate it out as infrared."

Amongthose who considered heat to be an important issue, most plan to opt for a heatsink 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 wayto dissipate heat.

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

Applications Abound

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

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

Respondents who want dimming tended to be more in thelighting or construction businesses. Engineers pointed out that dimming isparticularly important in construction of new buildings and offices, wherebuilders typically keep an eye on future trends.

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

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

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