LED lighting searching for balance between efficacy and efficiency

September 29, 2011 // By Christoph Hammerschmidt
There are many challenges for the fledgling LED lighting industry - but the chanced far outweigh limiting factors, several speakers at the LED Lighting Symposium LpS in Bregenz said. The challenges vary depending on the position of the respective speaker in the value chain.

One of the major challenges for the LED lighting industry is that the value chain currently is undergoing a reorganization process. Luminary manufactures need to acquire a number of new competencies, said Gerhard Kuhn, head of Osram Semiconductor's application team. "Luminary vendors need to add competencies in thermal management, electrical design and standards handling", he said in his keynote speech at the LpS. "A bad optical or thermal design or a poor driver can dramatically decrease the design of a LED lamp," Kuhn noted. As a consequence, the efficiency needs to be regarded not as a topic of the LED module alone, but of the entire product. "Efficiency needs to be optimized along the entire value chain", Kuhn demanded.

With LED lighting applications being field a wide open field where the designer's creativity can find ample chances to unfold, the differentiation at the market will be done by a new set of product features: Reliability, LED properties and power consumption, Kuhn predicted.

On a technical level, the indoor lighting application market is determined by the conflict between CCT (Correlated Color Temperature) versus CRI (Color Rendering Index). LED designers have to find the right trade-off between light quality and efficiency, between efficacy and efficiency.

In outdoor illumination applications, other factors are more in the foreground. In the first place, energy saving is the predominant driver for LED lighting success. But factors such as service lifetime, reliability and stability should not be underestimated either, Kuhn said. Reliability, in turn, is determined in the designers ability to master the influence of temperature, humidity and corrosive gases - after all, outdoor lighting in most cases is street lighting and as such exposed to the exhaust gases from cars. he provided an example, how this considerations influence LED lighting designers: "Silver corrodes very fast under these conditions, so designers should make sure they don't use silver in the reflectors of outdoor LEDs," Kuhn explained.