What Lies Beyond the Current LED Race?

As president of LED Lighting Technologies, Dr. M. Nisa Khan consults in the solid-state lighting industry and educates consumers about LED lighting. She has a bachelor’s degree in physics and mathematics, and master’s and Ph.D. degrees in electrical engineering. Email her at nisa.khan@iem-asset.com

Over the last four years, I’ve written ST columns on LED lamps’ technologies, challenges, safety, trends and markets. In addition to investigations and analysis, I’ve also compared LEDs to other, existing lighting systems, and discussed sign-industry applications. Interestingly, some my analytics may have been ahead of their time and, consequently, perceived as pessimistic by some readers.

However, because the science of light has been my interest and a branch of my profession for more than 25 years, I’ve periodically presented my scientific findings — some of which are still ongoing — to the various, related industries and, also, emphasized better ways to bring LED lighting in our lives.

Particularly, I’ve discussed and analyzed such LED-technology challenges as electrical requirements, omni-directionality, yield and thermal or lifespan complexities. These issues, today, more ubiquitously discussed, are familiar topics – or, in some instances, applied to real and pertinent applications.

Because of the industry’s current acknowledgment of existing (and past) complexities, I envision the solid-state-lighting (SSL) manufacturing field will move faster to resolve its challenges. The resulting advancements will cause LED lighting markets to substantially escalate over the next several years.

But what can we expect, say, beyond 2014? What does LED lighting’s long-term future look like?

Advertisement

As recently as the 2007 Lightfair tradeshow, many lighting companies, especially those lacking LED technology R&D programs, didn’t foresee LEDs as solutions for next-generation lighting.

At this year’s show, the same lighting companies proudly displayed LED-lamp prototypes — linear, tubular and compact – designed for various commercial and residential applications. Further, and accompanied by positive proclamations of LEDs’ future, these companies now tout new lamp configurations that, they say, illuminate living spaces in novel ways. Predictably, their marketing text claims LED technology offers greater advantages over incandescent and fluorescent lights.

Interestingly, such companies as Osram Sylvania, Philips and GE Lighting Solutions have, for some time, confidently developed LED technologies.

On the flip side, however, measurement results and analyses from the Dept. of Energy’s (DOE) recent, Round 11 CALiPER program tells a different story – at least for now. The Round 11 team used lamp samples available in August 2010, and their published reports (February and April 2011) indicate that fluorescent and incandescent lights still outperform LED equivalents, on average.

Further, although LED lamps and luminaires have higher efficacies than their incandescent counterparts, they still underperform in light output and other metrics. (You can review Round 11 details and other reports at www1.eere.energy.gov/buildings/ssl/reports.html.)

DOE findings
Lamp manufacturers who believe their T8-replacement LED products may outperform the DOE samples should recognize that, although LED counterparts may look brighter, the illusion stems from directly viewing the light source. LED lamp light generally seeds from a small (and often directional) source, but source brightness doesn’t translate to higher ambient light output, especially when compared to general light sources.

Advertisement

Further, higher efficacy measures don’t always translate to higher overall lamp efficiencies, because testers should only compare efficiencies when both lamp types’ light present equivalent output. And, even when equivalent, total-light output occurs for both LEDs and other lamps, their light distribution may be dissimilar. Thus, for particular applications, users and specifiers, including signmakers, might prefer (or need) one type of distribution over the others.

Although new DOE findings show notable improvements in LED lamps, similar conclusions for the LED T8’s were found in last year’s round-analysis (see ST, August 2010 LED Update, page 20). Regardless of the dynamics, the DOE tests and conclusions provide valuable information for retailers, manufacturers and buyers of LEDs for replacement lamps. However, due to today’s development speeds, many companies may now offer better products than those tested in Round 11.

Further, and despite the DOE’s findings (that LED replacement lamps currently underperform the incumbents), one shouldn’t assume their capabilities are under par when compared to tubular-fluorescent and compact, household-incandescent and fluorescent lamps.

Why? Market-available, LED-replacement lamps still use the fixtures and electrical-input configurations of incumbent lamps, and this prohibits LED engineers from utilizing their best light-source designs. In a perfect world, LED engineers would build components that provide the most desirable lighting functions with the highest efficiency at the lowest cost.

The DOE’s CALiPER staff didn’t analyze LED replacement lamps that specifically featured the technology’s best strengths.

At Lightfair, I learned that several manufacturing labs have various sophisticated and integrated LED luminaires under R&D that closely approximate fluorescent-T8 performance levels in light output, efficacy, distribution and color. I anticipate that selected versions will soon exceed both the current T5 and T8 performances.

Advertisement

However, such high-performance LED lamp technology only becomes a reality if significant capital, resources and commitments are directed toward it. First, investors and manufacturers must develop an understandings of the challenges, and, finally, decide whether it makes sense to pursue LED solutions for all lighting applications – and if not, which applications specifically.

R&D Funding
In recent times, the U.S. government and venture-capitalist funding for SSL development has increased. However, it’s insignificant compared to the funding supplied by Chinese, Japanese and South Korean governments and industry.

Note, also, that such companies as Mitsubishi, Panasonic and Toshiba are returning to the semiconductor-optoelectronics industry — the heart of laser and LED industries. These companies led the high-performance laser industry in the 90’s – but, and perhaps due to the ’90s tech-bubble burst — pulled out of the optoelectronics industry.

Now, with the promise of gains from commercial, residential and digital-gadget LED applications, these companies have re-entered the field with enormous capital and resource commitments.

Korean Samsung’s increasing dominance in electronics and optoelectronics products – especially LED technologies — is indeed remarkable.

China demonstrated its LED enthusiasm at the 2008 Beijing Olympics and the 2010 World Expo in Shanghai. Its government provides the world’s highest support for LED technology, product development and domestic adoption. Chinese manufacturers regularly produce inexpensive lamps for toys, indicators and night lights; they also make high-power lamps for general lighting via partnerships with foreign LED companies. In both cases, China customarily uses chips from foreign suppliers – although the government has plans to expand its in-country SSL development centers.

According to the June issue of Compound Semiconductors magazine, the Chinese government subsidizes up to 75% of new epitaxial reactor (MOCVD) costs. (MOCVD stands for Metal-Organic Chemical Vapor Deposition, a technique for depositing thin layers of atoms onto a semiconductor wafer.)

China also provides low-interest loans, tax breaks and free, fundamental real estate for LED manufacturers. Additionally, it recognizes that manufacturing LED chips is a economic source, and its import dependency cuts into profits and also provides other country’s with tools and resource controls that could become more costly in the future.

The magazine says high growth and incentives have already drawn nearly 60 Chinese LED manufacturers into LED chip production; some have joint-venture agreements with foreign chipmakers. In contrast, the U.S. has only a few commercial LED chipmakers, and many of these already have established packaging/manufacturing facilities in China.

Future market dynamics
LED market dynamics may change over the next five years due to slowing LCD-screen backlight demand and increasing needs in other sectors, such as street- and general-purpose lamps for commercial and residential usage. Such action will surely increase the overall LED market into 10’s of billions. Still, LEDs will unlikely replace many other lighting technologies, including fluorescent, incandescent and others, because the lighting industry is too big and diverse to truly be affected.

Although street lights, signs and screen backlights all benefit from LEDs’ directional, flat and discrete scaling features, general-purpose lighting demands additional performances that LED manufacturers are challenged to produce, such as broader and more uniform light distribution and color quality. The SSL industry race must soon turn toward higher and more sophisticated technologies to solve these challenges – but will first need to churn low-cost solutions.