Cree has announced another LED in its high-power XLamp family that is smaller than most mid-power LEDs yet delivers significantly more light output and includes primarily optics for beam control. The XB-H LEDs measure 2.45 mm per side yet can deliver more than 500 lm at 1.5 A and 25°C. Cree is positioning the LED as delivering the same level of output as the 3.45-mm XP-G2 or three times the light output of the XB-D family in the same small footprint.
The XB-H LED family is another step in Cree's recent push on increasing what it calls optical control factor (OCF). The company characterizes OCF as output divided by the area of emission and Cree is applying the metric from small discrete LEDs such as the XB-H to chip-on-board (COB) arrays. The point is that the smaller the light-emitting surface (LES) area, the better you can control the beam. Cree component product marketing manager Paul Scheidt said that high OCF is especially important in directional applications where the figure of merit for a solid-state lighting (SSL) product is often center beam candle power (CBCP) measured in cd.
Some SSL manufacturers are ready to take advantage of the performance of the new family. "With a high optical control factor, the XB-H LEDs enable new levels of brightness and optical control to improve design flexibility, increase performance, and lower system cost without sacrificing reliability,” said Roger Suen, supply chain management director at Light Engine Ltd. "Cree is the first LED manufacturer to bring this level of performance to such a small size."
Cree has characterized the XB-H LED primarily at the elevated drive current of 700 mA and 85°C temperature as those levels are more indicative to how the products are being used. At those conditions the flux output maxes out at 499 lm. The company did state maximum efficacy of 175 lm/W at 25°C, providing a comparison with the prior-generation products. Efficacy will drop slightly at higher temperature.
Cree will offer the LEDs over the range of 2700K to 8300K CCTs. CRI options will include 70, 80, 85, and 90 with the warmer CCTs getting the 90-CRI option and the cooler CCTs getting the 70-CRI option.
The new LED uses essentially the same die that Cree uses in the XP-G2 family with enhancements in the package architecture and optics. The fact that the XB-H is a follow-on product means that market transformation programs such as Energy Star will recognize products that use the LED after only 3000 hours of LM-80 testing, allowing quicker time to market for SSL manufacturers.
Cree has a number of other small LEDs in its portfolio as it has sought to deliver products in ceramic-based packages to compete with mid-power LEDs through better performance and reliability. Examples include the XH-G and XH-B LEDs that are 3 mm on a side, the XQ family that measures 1.6 mm on a side, and the previously mentioned XB-D family.