In  my early days as a reverse engineer at Chipworks, one of my most interesting (and challenging) projects involved materials identification and recreation of the processing sequence for a blue emitting LED. That was way back in 1998, so the idea of broad spectrum solid-state lighting was really new and the materials to create them - GaN for my particular device of interest - were truly exotic.

A lot of time along with product and market development have passed since I first got involved with these devices. Nowadays, the green movement has taken hold to the point that most of the general public has heard about the merits of LED lighting whether it’s for traffic lights, home lighting fixtures, or to supply the backlighting in LCD displays . In fact even my own  trailing edge household has switched to LED bulbs for our Christmas lights.

It was neither a trip down memory lane nor looking ahead to Christmas that got me thinking about LEDs today. It was a combination of a visit to a local failure analysis lab and the arrival of the Embedded.com newsletter today. Andreas Pohl, FAE at Avago, posted a good “Product How-to” article called, Build multicolor sign and video wall apps with RGB LEDs.

I imagine there are more than a few challenges to creating these massive electronic billboards out of millions of discrete RGB LED packages. Since these displays need to be viewed by many tens of thousands of spectators, viewing angle considerations are obviously a big issue. Andreas discusses thermal management to enhance performance and stability, so it seems natural to start thinking about device reliability.

LED lifetime is exactly what I discussed on a recent tour of the failure analysis labs of MuAnalysis. Martine Simard-Normandin is the founder and chief scientist along with the many other hats she wears at her company which she spun out of the former Nortel fab many years ago. Martine and I discussed LED reliability issues and the concerns many customers of the devices would have.  If a few of my decorative bulbs burn out on my Christmas tree, I’m not likely to get too upset. After all, Home Depot did give me a few bucks off for trading in my old energy-hogging incandescent light strings. But the purchaser of a multi-million dollar stadium scoreboard might take a different approach.

The MuAnalysis staff have taken a keen interest in LED technology especially getting a better understanding of their reliability. This is quite evident from looking at the long list of teardown reports they currently offer. Whether or not you need this type of information badly enough to buy one of their reports, the MuAnalysis website offers a limited but useful amount of free information for each of its published reports. There is even a complete MuAnalysis sample teardown report available for download that is an excellent place to start if you really want to learn more about LED technology.

Another free web resource for learning about LEDs is Bill Schweber’s Fundamentals of LED Dimming available with registration at TechOnline. Bill provides a lot of background on the use of LEDs for lighting and also identifies packaging, thermal management, and ultimately LED failure in arrays as major design considerations.

If you actually do need to know more and have the budget to buy a full report, I can definitely recommend the MuAnalysis teardowns. My former employer is a MuAnalysis partner and once asked me to read through their LED teardowns and write marketing materials for them. The MuAnalysis LED teardowns are comprehensive, well-written, very high quality reports. If better ones exist, I have not seen them.