Issue link: https://iconnect007.uberflip.com/i/1007258
54 FLEX007 MAGAZINE I JULY 2018 ity. It was initially used on weapons guidance systems, military avionics, missiles, satellites, detonation hardware and other applications where the electronics must survive extreme shock—sometimes tens of thousands of g's— and not fail. Traditional connectors and flex cables just can't do that. Because the flex part of the board extends all the way through the rigid sections of the board, rigid-flex boards can take enormous punishment and still remain functional. It is the preferred packaging method for missiles, jet fighters, ruggedized military cameras, and all method of weapons systems, includ- ing optics for conventional rifles and mortar launchers. More recently, rigid-flex is being applied to unmanned vehicles/war fighters, drones, underwater vehicles, remote/unat- tended ground sen- sors dropped from aircraft, and other creative uses. It's easy to over- look rigid-flex if you don't think your product is subjected to high g-forces. But everyday items can have pretty tough duty cycles as well. We had a commercial application a few years ago for a camera module— a very simple rigid-flex board. One of the customer's key test vehicles operated akin to tumbling the device in a clothes dryer until it failed. The rigid-flex boards never failed, but the traditional connectors with flex cables eventually did. The difference was signif - icant enough that the mean time between fail- ure on their products had a dramatic reduction, sa ving the company much more than the initial outlay for the rigid-flex boards. High-vibration environments also prove the worth of rigid-flex packaging, again finding wide use in missiles, space systems, and weapons that have to endure high shock and high vibration. But they have also been commonly used in elec - tronics for helicopters, aircraft anti-lock brake systems, ruggedized cameras/infrared cameras, displays, aircraft autopilots, avionics and other electronics. Some of the more unusual applica - tions we have worked on include a dog collar, a bicycle computer, a ruggedized solid-state hard drive, and a very thin, lightweight 12-layer board for a robot that climbs into volcanoes and reports until it expires. Rigid-flex for high-density applications fall into two general categories. The first is when there simply is no more room for connectors, and when every precious square inch is nec- essary for components. We see this a lot in implantable pacemakers/defibrillators, diabe- tes pumps, hearing aids, cameras, video cam- eras, military heads-up displays, goggles and vision systems. One of the more creative uses of rigid-flex boards is the Medtronic Pill Cam, a camera that is swallowed like a pill to allow physi- cians to diagnose Crohn's disease and other intestinal ail- ments. The second use of rigid-flex in high-den- sity applications occurs when there still may be enough room for connec- tors and flex cables, but the designer is trying to get the Figure 1: Rigid-flex boards allow the electronics to fit to the form of the device. Because the flex part of the board extends all the way through the rigid sections of the board, rigid-flex boards can take enormous punishment and still remain functional.