LED prototypes aim at automotive headlight applications

September 23, 2011 // By Christoph Hammerschmidt
At the upcoming International Symposium on Automotive Lighting (ISAL) in Darmstadt (Germany) Osram Opto Semiconductors will be showcasing two new LED prototypes for headlights with innovative chip and package technologies. Properties include high light output even at high currents, a uniform light pattern, thermal stability and a particularly good contrast ratio.

LED headlights have to perform various functions and cope with changing ambient conditions, including the high temperatures in the headlight itself. To meet these requirements Osram has developed the LED prototypes Oslon Black Flat and Osram Ostar Headlamp Pro.

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). With a typical thermal resistance of 5 K/W is it 20% better than the other member of the Black Series. The black package stands for high stability because the thermal coefficient of expansion of the special material matches the coefficient of expansion of the metal core board. The new LED does not require a lens so its light can be injected very close to the light guide. The solder pad is identical to the ones used in the entire range so the light output can be significantly increased from a largely identical board design. With a power draw of 2.3 W and an operating current of 700 mA, the new product achieves a typical luminous flux of 190 lm.

According to Osram, the Ostar Headlamp Pro meets a wide range of requirements in terms of output and adaptability to ambient conditions. It offers a more uniform light pattern, better thermal stability and greater brightness than its predecessor. The 20 x 20 mm high-flux LED is available with two to five chips.

AFS functionality (Adaptive Frontlighting System) can 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 around 250 lm for the single chip (1 A operating current) – and therefore 1250 lm for the 5-chip version. The thermal resistance of the 5-chip version is 2.1 K and is therefore 0.5 K less than for the predecessor model.

All new prototypes are based on Osram's UX:3 chip technology.