The Electronics Research & Service Organization (ERSO) of the government-backed Industrial Technology Research Institute (ITRI) inaugurated a program early this year to ease the entry of Taiwan`s LED makers into high-end markets.



The program is dubbed the "Houyi Plan" after a mythical hero who shot down nine of the 10 suns that were scorching China in ancient times. "We christened the program in his name," explains Dr. Chan Yijen, ERSO`s deputy general director, "because we believe that LEDs will get rid of most existing light sources, just like Houyi brought down those nine suns."

Chan reports that the ultimate goal of the program is to develop white-light LED lamps that give off 100-120 lumens per watt while keeping the cost below US$5 per 1,000 lumens. This is necessary, he explains, because "Only with such efficiency can the lamps be competitive."

ITRI statistics show that Taiwan is the world`s No. 2 exporter of LEDs. The domestic industry is now suffering sluggish growth, however, because the number of new LED applications have declined and because its products are not very competitive with those from the United States and Japan in high-end markets.

LEDs have become a target for development in the industrially advanced countries because of their energy-saving and toxicity-free properties. Insiders in mainland China estimate that by 2025, solid lighting (mostly LEDs) will account for sales of US$50 billion and save as much as US$35 billion worth of electricity worldwide each year.

Huge Growth

Strategies Unlimited, an American market-research organization, estimates the compound annual growth rate of the global LED market for the 2002-2008 period at 40%.

"In the face of such lucrative opportunities," Chan stresses, "there is no reason for Taiwanese LED-lighting manufacturers to absent themselves from the market."

The Houyi plan will help them to continue growing in the market. The program focuses on ultra-bright white LED technology and will encompass wafer, chip, packaging, and application systems.

"To get around patent issues," he says, "our white LED technology will be based on ultraviolet chips that use red, green, and blue phosphor powders. Leaving the patent issue aside, white light beamed from UV chips delivers much better color rendition quality than does the light emitted from blue chips."

Once the white-light technology is developed, Chan and his team will apply it first to surgical lamps and high-intensity outdoor lamps. "Surgical lamps demand good color rendition," he explains, "while high-intensity outdoor lamps require extra-strong illumination ranging from 8,000 to 10,000 lumens."

One of the Houyi plan`s key sub-projects concentrates on thermal dissipation, which is intimately related to how soon an LED lamp will deteriorate in the amount of light emitted. ERSO has unveiled a unique packaging methodology to address this issue, and has transferred it to Forward Electronics, an LED packager belonging to the Tatung Group. Forward Electronics plans to use the methodology for packaging LED chips for lighting purposes.

Dr. Sun Chienjen, deputy director of ERSO`s Optoelectronics Device and System Application Division, claims that the new methodology is able to keep heat resistance inside the packaged body to under 0.3 degrees Celsius for each watt of electricity consumed.

Irregular Surface Dissipates Heat Better

"We`ve named this the `cubic packaging` methodology," Sun reports. "It increases the surface area of packaged LEDs by creating irregular segments on the surface. When the surface area increases, the heat emitted from the core soon dissipates." By contrast, he notes, most packagers use "flat packaging methodology," keeping the surface smooth, and this results in inferior heat dissipation.

"Another advantage of cubic packaging methodology," Sun goes on, "is that it has fewer resistance interface layers. We employ unique technology to eliminate packaging for some individual devices like circuits, substrates, and the wires inside the packaged body to reduce the number of layers. That`s how we can keep the heat resistance inside a 3-cubic-centimeter packaged body to under 0.3 degrees." This new technology has been patented.

The improved methodology is a blessing for all in the industry. "For a long time," Sun comments, "thermal problems were a major issue that caused midstream and downstream manufacturers to blame each other. We hope that our effective packaging methodology will do away with this issue."

The 3-cubic-centimeter package was designed especially so that lighting manufacturers will be able to build lighting modules of different sizes by combining these cubic units together.

Sun notes that Taiwanese LED makers have been able to cut the prices of diodes since they began mass production in 2000. However, he emphasizes, "It was almost impossible for them to break into the lighting market so long as the thermal problem was not fixed."

With the problem now fixed, Forward Electronics is using the new packaging methodology to develop lighting modules that consume five to 10 watts of electricity to provide illumination for general lighting, automobile lighting, and billboard lighting.
(by Ken Liu)