BridgeLux, Inc, a US-based supplier of high-power LED chips has introduced the KO family of LEDs, including what the company describes as the only 60-mil (1.5 mm) chip available in production volumes today.
High-power LEDs are usually classified as devices operating from a power level of more than 0.5 W, with a drive current of more than 150 mA. Typical one-watt class LEDs operate at 350 mA and the chip size is generally of the order of 1 mm square.
|KO blue chip|
The KO family of blue LED chips is available in 60, 40, 30 and 24-mil chip sizes (1.5mm to 0.6mm). Color choices for the1.5mm KO are 445 to 475-nm blue, as well as high efficiency cyan and green. Die bonding options include traditional silver epoxy as well as the newer eutectic techniques.
BridgeLux says that the 60-mil KO chip can support up to 1.2A drive current. When combined with phosphors to generate white light, the chip enables a targeted white output of 140 lumens, depending upon packaging design. The entire family is designed to stand up to 150oC junction temperatures and 40% higher drive currents than is commonly found for similarly sized devices.
"The development objective with the KO series was to reduce the input voltage while increasing the overall light extraction," said BridgeLux CEO Robert Walker. "The net result is a fully scalable family of LED chips that yields a 10-30% increase in light output efficiency."
Decreasing the forward voltage required for a given drive current results in a device with lower overall power consumption and lower heat generation for a given amount of light, all of which contribute to producing more lumens-per-watt.
"These chips are designed for brightness," continued Walker. "Combining 6 of these devices produces roughly the light output of your typical 60-watt incandescent bulb, but requires less than one-third the power. We’ve nicknamed the 60-mil KO the 'bulb buster' since we have something here that can really begin to challenge traditional lighting solutions in general purpose illumination."