Solid state lighting (SSL) is recognized as the second revolution in the history of lighting. The primary reason is the annual global energy bill saving of€ 300 billion and a reduction of 1,000 MT of CO2 emission. As such, the SSL industry is expected to exceed€ 80 billion by 2020, which will in turn create new employment opportunities and revenues. A second reason is the promise of a long useful lifetime, with claims up to 80,000 h. As with any products, the consistency and reliability of SSL systems need to be ensured before they can be adopted in any applications. To add to the complexity, there is also a need to ensure that the cost of this technology needs to be comparable or even lower than the current technology. Although SSL systems with low reliability requirements have already been developed, they can only be used in applications that operate in modest environments or in noncritical applications. For demanding applications in terms of environmental conditions, such as automotive application, or where strict consistency is needed, such as healthcare applications and horticulture applications, the conventional lighting sources are currently still preferred until the reliability of SSL is proven in these applications. Therefore, the knowledge of reliability is crucial for the business success of SSL, but it is also a very scientific challenge. In principle, all components (LEDs, optics, drive electronics, controls, and thermal design) as well as the integrated system must live equally long and be highly efficient in order to fully utilize the product lifetime, compete with conventional light sources, and save energy.

It is currently not possible to qualify the SSL lifetime (10 years and beyond) before these products are available in the commercial market. This is a rather new challenge, since typical consumer electronics devices are expected to function for only 2–3 years. Predicting the reliability of traditional electronics devices is already very challenging due to their multidisciplinary issues, as well as their strong dependence on materials, design, manufacturing, and application. Predicting SSL reliability will be even more challenging since they are comprised of several levels and length scales of different failure modes. The tendency towards system integration, via advanced luminaries, System-in-Package approaches, and even heterogeneous 3D integrations poses an additional challenge on SSL reliability.