At the International Symposium on Automotive Lighting (ISAL 2011) in Darmstadt (26-28 September), Osram Opto Semiconductors GmbH of Regensburg, Germany showcased two new LED prototypes that combine new chip and package technologies to provide high light output (even at high currents), a uniform light pattern, thermal stability and good contrast ratio. The OSLON Black Flat and OSTAR Headlamp Pro are matched to the requirements of headlight systems and are designed to provide headlight manufacturers with superior performance and optimized cost.

More and more flexibility is needed for the light sources used in headlights, says Osram. Not only do they have to be reliable and provide the appropriate amount of light in all visibility and driving conditions, they have to perform various functions and adjust to changing ambient conditions, including high temperatures in the headlight itself. Osram says that it has developed the new LEDs to meet all of these requirements.

OSLON Black Flat is the latest addition to the OSLON Black Series and is equipped with a ceramic converter and a QFN package (quad flat no leads). Its typical thermal resistance of 5K/W is 20% better than the traditional OSLON Black Series. The black package represents high stability because the coefficient of thermal expansion of the LED matches the coefficient of expansion of the metal core board. The flat top, lens-free design suits the close coupling needed for light guide designs and maximizes the in-coupling of light, says the firm. The solder pad is identical to the other members of the OSLON family (OSLON Black, OSLON MX and OSLON SX), which enables a wide range of light output from a largely identical board design. With a power draw of 2.3W and an operating current of 700mA, the new OSLON Black Flat achieves a typical luminous flux of 190lm.

The OSTAR Headlamp Pro is able to meet a wide range of requirements in terms of output and adaptability to ambient conditions. It offers a more uniform light pattern, better thermal stability (more usable warm lumens) and greater brightness than its OSTAR Headlamp predecessor. The new 20mm x 20mm high-flux LED is available in two- to five-chip configurations. The new OSTAR LED offers headlight makers better performance at lower costs, claims the firm. AFS (Adaptive Frontlighting System) functionality can now be achieved with chips that can be controlled individually or in series. This leads to configurations that allow matrix chip solutions. Typical luminous flux values are about 250lm for a single chip (1A operating current), equating to 1250lm for the 5-chip version. The thermal resistance of the 5-chip version has been reduced to 2.1K/W, which is 0.5K less (a 20% improvement) compared with its predecessor.

“The two new prototypes combine new technologies with new functionality and are perfectly matched to the demanding automotive requirements of headlight systems,” claims Peter Knittl, Osram’s director of Automotive LED. “This makes them particularly attractive for widespread use in all vehicle classes,” he adds. The design of the prototypes uses Osram’s new UX:3 chip technology (which produces high light output even at high currents) and a ceramic converter (which provides a uniform light pattern). Additionally, encapsulation of the chips directly in the reflector produces a defined light/dark boundary in the light pattern, providing a particularly good contrast ratio for simpler and improved optical designs. Such properties make the LEDs suitable for efficient use in headlights, claims Osram Opto.