Markus Hofmann

OSRAM Opto Semiconductors, Senior Key Expert

Markus Hofmann

OSRAM Opto Semiconductors, Senior Key Expert


Markus Hofmann is Senior Key Expert for Lighting Modules in the SSL application engineering department at OSRAM Opto Semiconductors in Regensburg. After graduating from the University of Applied Sciences in Regensburg with a diploma in Electrical Engineering, he joined OSRAM Opto Semiconductors in 2000. At this time he worked on LED technology and applications for automotive interior and exterior lighting. In 2008 he started to work for OSRAM GmbH as a technical project leader for LED retrofit lamps. Since 2015 he is at OSRAM Opto Semiconductors and works as Application Engineer for general lighting LEDs.

New Outdoor Stable LED Technology Enables Cost Efficient and Compact Luminaire Designs

In the last years, LEDs have succeeded to penetrate the general lighting market – they can be found in various applications, like street lighting, or LED retrofit bulbs. This success story was enabled by the improvement of LED efficacy, color quality, reliability and last but not least by the continuous reduction of prices. Although it seems that the progress of the LED technology has slowed down, the LED still can show significant improvements which help lighting engineers to improve their systems. With the introduction of the DURIS® P family, OSRAM Opto Semiconductors offers a series of LEDs with several benefits.

The DURIS® P LED family is based on a standard leadframe technology and thus has an improved lumen per Dollar ratio. Nevertheless it can fulfil the harsh requirements of an LED for use in outdoor luminaires. Robustness tests with Junction temperatures above the specified maximum limit show a stable lumen maintenance and the exposure to a Hydrogen Sulphide test does not harm the LED. Especially outdoor luminaires are exposed to large temperature variations over the year. These thermal cycles impose stress on the solder joint between LED and PCB. As the CTE (Coefficient of thermal expansion) mismatch between LED and PCB is small for the DURIS® P family, the risk of a catastrophic failure is decreased.

A low thermal resistance allows improvements on system level. This makes it possible to run the LED at higher currents, while keeping the junction temperature at a moderate level. This paper will also give an example of an optical evaluation for street lighting using an off-the shelf lens together with an LED from the DURIS® P family.

Lessons Learned

  • Overview of the DURIS® P family.
  • Insights in Robustness testing of the LED.
  • Detailed look on reliability of solder joints and robustness during thermal cycling.
  • Understand the advantage of a low thermal resistance and how to translate to system level benefits.
  • Example of an optical evaluation for street lighting.

All session by Markus Hofmann

Session 5

14:30 - 16:30
LED professional Symposium +Expo
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