LEDs could fulfill everyday lighting functions by 2010, says iSuppli report

El Segundo (CA) - Light-emitting diodes (LEDs) are gaining ground as everyday illumination tools, supplanting costly, heat-generating bulbs in handheld devices, especially for backlighting LCD displays in cell phones and PDAs. According to a new report from market research firm iSuppli, as advances in technology enable LED light capacity to increase, and as manufacturing costs become competitive with incandescent and fluorescent lighting, LEDs could provide a new and cost-effective alternative for everyday spot lighting.

According to Jagdish Rebello Ph. D., principal analyst at iSuppli and author of the report, LEDs constituted a $12 billion market in 2004. The portion of the LED market devoted to general illumination last year was estimated to be $94 million, though Dr. Rebello predicted a 52.3% compound rate of annual growth in that market, to as much as $875 million by 2010.

"While LEDs will not aggressively penetrate the home and general illumination markets before 2010," writes Dr. Rebello, "clearly the future of most lighting applications belongs to LEDs."

Six-year projection of general-illumination LED market (source : iSuppli)

Dr. Rebello did point out tremendous gains would need to be achieved, not only in mechanical efficiency but also in marketing and packaging an "LED bulb," before it could become practical for use in general illumination. "If you went to Home Depot, you would have to spend $70 on LEDs that put out the same light as a one-dollar incandescent bulb," writes Dr. Rebello.

Currently, there are no LEDs in production that can emit pure white light, Dr. Rebello points out in his study, since white is comprised of all color frequencies in the optical spectrum. As of now, there are three creative ways of coaxing LEDs to produce something approaching "white :" A phosphor placed in front of a blue LED will convert some of the blue light into red and yellow, thus making the resulting glow appear white. The second method clusters red, green and blue LEDs into the same package, letting optics perform the miracle for itself. And the third method - which is not too popular - involves putting a filter in front of an ultraviolet LED.

In May 2005, Osram Opto Semiconductors announced its newest so-called "white LED," producing an amazing 200 lumens - roughly the output of a 25watt incandescent bulb. Theoretically, you could make a wall of these and flood your living room with light, but it doesnt make sense at current prices of at least $35 per LED (fixture and housing not included). The initial cost obviously far outweighs the savings in electricity.

Increasing the output and efficiency of these "white" LEDs while lowering costs is what could cause consumers to migrate to LEDs for household lighting, according to iSuppli. Currently, white LEDs produce 60 lumens/watt, but you would need 80 to 100 lm/W to become cost competitive with the 65 lm/W of fluorescent tubes and 17 lm/W of incandescents, according to US Department of Energy figures. Dr. Rebello considers these DOE benchmarks the "holy grail" of LEDs, which could be achieved around 2010.

Finally, what about the so-called "organic LEDs" (OLED) that received so much press in the last few years ? According to iSuppli, OLED hasn’t caught on in the market, due to its fragility and short lifespan. Environmental factors such as humidity and oxygen break down the material, reducing its light output dramatically. While regular LEDs will lose about 10% of their brightness over 50,000 to 100,000 service hours, OLEDs will rapidly lose 50% of their brightness over 10,000 hours. Dr. Rebello remarks that technology is in the works for extending the lifespan of OLEDs.