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Taiwanese AC-LED Alliance Eyes June Launch

LEDs feature a pair of active layers to provide better electrical efficiency than existing emitters.

Chipmakers Epistar and Forepi are participating in a Taiwanese collaboration looking to overcome the need to convert AC mains current to DC to power LED lighting.

Developed by Taiwan s Industrial Technological Research Institute (ITRI), the "AceLED" technology is now being commercialized by 22 of its compatriot companies, which will begin to sample products in 2009.

“All the members are now focusing on the measurement standard and the safety regulation issues of the AC LED," an ITRI spokesperson told

“The first edition of the standard and some products will be provided in June."

ITRI s AceLED technology is based on paired light-emitters that are produced on the same wafer but connected in parallel, and in opposite orientations. The technology institute filed its first US patents on this approach in 2006.

The paired arrangement allows each diode to operate in turn under alternating current, and protects them from damage by electrostatic discharge.

With conventional LEDs this would mean that only half of the devices would emit at any one time, but to get around this problem the ITRI team has patented the use of microdiodes containing two active layers.

Using this approach, one layer emits light during the positive half-cycle of an alternating-current supply, while the second emits during the negative half-cycle.

The AceLEDs also use numerous microdiodes connected in series and in parallel, protecting them from breakdown that would conventionally threaten LEDs under reverse bias.

Lamps produced using AceLEDs so far only boast luminous efficacy of 50 lm/W, less than the 80 lm/W in ITRI s examples of comparable luminaires using regular commercial LEDs.

However, at 95 percent the electrical efficiency of the AceLED luminaire is higher than the 80 percent figure shown by normal luminaires, which require conversion to a DC input.

With the help of its industrial partners, ITRI is now hoping to produce 80 lm/W AceLED luminaires next year.

“We expect that the total cost would be less than the energy saving light bulbs and DC LEDs in 2010," the institute's spokesman said.

The partners collaborating with ITRI are forming technology and product groups to bring AceLEDs to market in the shortest possible time. The research center will provide them with its technology, but the different partners will make their own decisions on whether to collaborate between themselves on production or not.

• The full list of ITRI s collaborators is: I-Chiun, China Electric, Kingbright, Lite-On, Elsa, Keepertech, Chroma, Intematix, Neo-Neon, Upkey, Liquidleds, Epistar, SCI, Lei Yueh, Tyntek, Forward, Lustrous, Everlight, Crystotech, Forepi, and Lastertech.

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