This article was published in the February 2013 issue of LEDs Magazine.

View the Table of Contents and download the PDF file of the complete February 2013 issue, or view the E-zine version in your browser.

+++++

Many companies in the lighting industry are struggling with profitability in the transition to LED-based lighting. Luminaire manufacturers are seeing their R&D costs and stock levels increasing. They are writing off increasing quantities of obsolete stock, and are facing increasing risk of quality problems in the field. Zhaga standards can help with these issues and accelerate the adoption of solid-state lighting (SSL).

I spoke with a number of lighting manufacturers who had increased their R&D spending from around 3% of sales in 2006, when they were designing luminaires with conventional light sources only, to 6% of sales last year, when 80% of the total went on developing LED luminaires.

Such a high level of R&D spending does not look sustainable for luminaire manufacturers. Costs will have to go down - not just R&D costs, but also the cost of stock, stock obsolescence, and the cost of quality. Why has the R&D cost increased so much? Partly because LEDs change faster than luminaires, and partly because it is challenging to make reliable luminaires that deliver the expected long lifetime.

Modular design helps. In a modular luminaire architecture, the LED technology is separated from the optical and mechanical parts of the luminaire. The R&D effort can then be focused on maintaining the LED module, a term that is used here loosely to define the part of the luminaire that contains the LED technology.

Most luminaire companies already use modular architectures – this is the only way to develop and maintain a broad portfolio of luminaires. While it may be obvious to separate the LED technology, the choice of make vs buy is less straightforward. Making your own PCB with LEDs is attractive, and the cost is lower than buying the equivalent off-the-shelf module. This will get you luminaires with minimum bill-of-materials (BOM) cost. On the other hand, proprietary LED modules are a burden for the R&D department, and the design and maintenance of the modules will increase your R&D cost.

Designing your own LED modules has other pitfalls. It is easy to get started, but soon you will need variants for other color temperatures, light levels and CRI values. Before you know it the R&D department has doubled its number of engineers.

Are you better off buying LED modules? Not necessarily. They are more expensive, and their integration into the luminaire still needs careful engineering to make the luminaire reliable. Furthermore, a module that is competitive today may be outdated, or even unavailable, a year from now. The dilemma seems to be whether you should reduce the R&D cost or the BOM cost. And what is the effect on your stock levels, the risk of obsolete stock, and the diversity of your luminaire product portfolio?

Zhaga offers a way out of this dilemma. By specifying the interfaces of a series of different LED modules, which Zhaga terms “LED light engines,” Zhaga makes it possible for module manufacturers to supply interchangeable LED light sources. In the context of Zhaga, two LED light engines are said to be interchangeable when the luminaire manufacturer can use either LED light engine without making any change in the design (mechanical, optical, thermal, or electrical) of the luminaire.

Luminaire manufacturers benefit from interchangeability because they can more easily switch from one supplier to another. The availability of a second-source supplier reduces risk. Not only will interchangeable LED light engines be more competitive, they are less vulnerable to supply issues, and that helps reduce stock levels and the risk of obsolescence. A subtle benefit is that interchangeable LED light engines will offer more choice in terms of CRI, CCT, lumen levels, lifetime, color stability, etc. This offers luminaire manufacturers the possibility to play with different performance/price levels in their luminaire portfolio without increasing their R&D costs.

The impact of Zhaga is already visible. For example, suppliers of linear indoor modules have started to offer products with the mechanical dimensions and fixation specified in Zhaga Book 7, even though that specification has not been published yet. Even if you choose to design and manufacture your own linear modules, it now makes sense to make them compatible with Zhaga Book 7. You may want to purchase these modules later from an external supplier.