News

16 March 2009

 

Epistar to ship AC-LED products in Q2/09

Courtesy of LEDs Magazine

Taiwan-based LED chip maker Epistar says it expects to be the first firm in the world to make volume shipments of alternate-current LED (AC-LED) chips to packaging houses, starting in second-quarter 2009 (shipping to clients in Taiwan, China and Malaysia). Lighting products using the chips are expected to be available on the market as early third-quarter 2009.

Epistar has been developing AC-LED chips since 2004 and has filed more than 10 patent applications in related fields. In February 2008, the firm also licensed a patent for AC-LED technology from Taiwan's government-funded Industrial Technology Research Institute (ITRI), which has established a patent portfolio that includes design, processing, packaging and applications for AC-LEDs. On 3 October, ITRI teamed with Taiwanese 19 firms (including Epistar, Lite-On Technology, and Formosa Epitaxy) to create an ‘AC LED Application Research Alliance’, with the aim to “expedite new product development and promote this burgeoning market”. Alliance members now number 22.

Epistar says that it is aware of the lighting industry’s desire for a ‘two-wire solution’, i.e. a light engine without complicated electronics. The AC-LED concept simplifies system design by making the AC-DC converter redundant. For a conventional DC-driven LED design, the AC-DC converter introduces a conversion loss typically of 15-30%. Any reliability issues with the converter are also eliminated.

Epistar acknowledges that the luminous efficacy of an AC-LED is lower than that of a DC-LED at the same chip size. However, based on the cost saving from eliminating the AC-DC converter, Epistar is working with a larger chip size, currently 55 mil per side, equivalent to about 1.4 mm. Many ‘1 Watt class’ DC-driven LEDs measure 1 mm (40 mil) per side.

Epistar says that its AC-LED chip, when driven at 1W, has an efficacy of up to 70lm/W at a color temperature of 5700K. This is equivalent to a DC-driven LED with 85lm/W efficacy and a converter with 15% conversion loss, claims the firm.

Epistar joins a small number of suppliers that have been at the forefront of AC-LED development including, most notably, Korea's Seoul Semiconductor (which makes power LEDs that can be connected directly to an AC source) and Lynk Labs (which make AC-driven modules and light engines).

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