Seeing the light: LEDs are no longer just for the "on" switch.

Author:Waddell, Pete
Position:DATABASE
 
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EVERY MONTH BETWEEN publication cycles, I try to reach out to designers to find out how things are going, what they working on, and of course, to find out if anybody has acquired any cool new guitars. Last week I talked to a friend (my twin brother of a different mother) many readers may know: Kelly Dack. Kelly works for IGT in Reno, NV. Not only does Kelly get to enjoy working and living in one of the most fantastic areas of the US, he and his colleagues at ITG get to work on some interesting boards. Those colorful and musical machines you see at any casino? ITG designs and builds them. If you've been to a casino lately, you may have noticed the flashing and pulsing lights that accompany the siren songs are changing. They are migrating to LED technology. According to Kelly, even the enticing sign that welcomes people to Reno is now lit by LEDs.

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To people like me who have retired from daily board designing, LEDs were always a small part of our designs. They were employed to alert you whether the computer was on, or the car engine needed an oil change or something like that. Today, LEDs are at the heart of a dramatic change in energy conservation. They are no longer the little "ON" lights: They are the illumination for everything. Kelly and others have told me about boards chock full of LEDs. But there are issues with these boards with which more designers are going to have to contend and find answers.

From what I hear, a big issue right now is thermal management. When you put a bunch of LEDs on a single board, the heat buildup can be so significant as to cause failures. Some people are using heat sinks, bus bars and fans, of course. But going forward there will have to be better solutions. Metal core boards may be one answer, but other creative solutions are going to be required. I've heard that people are experimenting with cutouts in the substrate to get more direct contact with a metal core.

Another problem is one of capability and capacity on the manufacturing side. As reported by Mike Buetow, our manufacturing and business guru, only 15% to 20% of the EMS companies have production experience with metal core boards. As we all know, it does no good to design "it" if "it" can't be manufactured at a reasonable cost and delivery. And then there is the issue of component traceability. Different LEDs have different light-emitting properties that are denoted by a "bin" code. Bin codes...

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